Patent Application
20230286565
This invention relates to a robotic cart platform that converts a conventional manually pushed utility cart into an autonomous utility cart with manual and autonomous modes of operation, tracks the movements of the cart in both modes of operation, warns when unsafe loading conditions occur and is operable with or without a wireless communication system.
A wide variety of businesses rely on utility carts to move items around inside their buildings. The carts hold and transport tools, equipment, component parts and completed products, many of which are heavy, bulky or awkward to carry, and often include associated paperwork that needs to be kept with an item as it moves from station to station or room to room. The carts come in a wide variety of shapes, sizes and styles. The corners of the carts typically include vertical risers and multiple horizontal trays. The carts are typically made of plastic or metal, and their front and rear corners are typically supported by caster wheels. Plastic carts often have trays and risers made of molded foam plastic. Metal carts frequently have metal tubes for risers and meshed wire baskets for trays. Some carts have metal tube risers and reinforced plastic trays. The utility carts are often rated for 200 to 500 lbs (90 to 225 kg) load capacities. Examples of these utility carts are made by Rubbermaid Commercial Products, LLC of Winchester, VA and sold as Uline Model Nos. H-1053, H-2470, H-2471, H-2475 and H-2505, AMSA, Inc. of Boulder, CO and sold as Uline Model Nos. H2505 and H7435, and Suncast Technologies, LLC of Palm Beach Gardens, FL and sold as Model No. PUCPN1937. These and other utility carts are shown and described in U.S. Pat. Nos. D618,418 and D618,419 to Cotron, U.S. Pat. Nos. D798,018 and D855,275 to Walter and U.S. Pat. No. 10,377,403 to Lee, the contents of which are incorporated by reference.
Autonomous mobile robots for manufacturing, warehouse and distribution applications are well known. Examples include 6 River Systems’ CHUCK robot and U.S. Pat. Nos. 10,294,028 and D826,508, Amazon Robotics’ MARTI robot and U.S. Pat. Nos. 7,920,962, 8,280,547, 8,265,873 and 10,317,893, Aethon’s TUG robot and U.S. Pat. Nos. 7,100,725, 7,431,115, 8,204,624, 9,223,313, 9,563,206 and 9,679,270, GreyOrange’s BUTLER robot and U.S. Pat. Nos. 10,216,193 and 10,481,612, Clearpath Robotic’s manipulatable mobile robot and U.S. Pat. No. D812,663, Fetch Robotic’s mobile warehouse robot and U.S. Pat. No. 10,423,150, InVia Robotics’ autonomous warehouse robots and U.S. Pat. No. 9,731,896, Locus Robotics’ warehouse robot and U.S. Pat. No. 10,019,015, Canvas Technology’s robots, and MiR’s mobile industrial robots.
One problem with conventional autonomous mobile robots is their integral design. Many components form the autonomous navigation structures, such as environmental mapping and proximity sensors, a power supply, control and drive systems, warning systems and a wireless system. These components and their associated wiring are built into the overall robot design. Even when the robot takes the form of a cart, the components that form the autonomous navigation structures are built into the overall cart design. Determining the locations of the various sensors and their wiring so they can perform their intended function while keeping them safe from inadvertent damage and out of the way from interfering with the normal operation of the cart can be particularly challenging. Businesses must either buy manual carts or dramatically more expensive autonomous robotic carts. Due to their complexity, there is no presently known way to convert a manual cart into an autonomous cart. Existing navigation structures are not intended to convert an off-the-shelf, manually pushed cart into an autonomous mobile robotic cart.
Another problem with conventional autonomous vehicles is their dependency on wireless communication with an independent operating system. The robots do not operate independently. They require wireless communication with an off-board database or control system. The operator must interact with the operating system and database via a wireless communication system such as WiFi to control the movements of the robotic vehicle. The cost of installing a wireless communication system such as WiFi can be prohibitively expensive for many organizations. Moreover, even when a wireless communication system is installed, the system may include dead zones that can sever communication with an autonomous vehicle, or cause the vehicle to receive redundant signals when multiple communication cells or transceivers are transmitting a given signal. When the autonomous vehicle stops in a dead zone, the robot must be manual pushed out of the dead zone and reset to advise it of its current location.
A further problem with conventional robotic carts is they are not compatible with manual operation. First, many conventional robotic carts do not allow for manual movement. If a user attempts to push a robotic cart, the wheels drag or turn with a high amount of resistance. Second, robotic carts become disoriented when they are manually pushed to a different location than the location to which the cart last autonomously moved. They cannot determine their location when the robotic cart is turned off and manually moved. When power to the robot microprocessor and drive motor are turned off, the robot loses its ability to track its movements and determine its location. When the robotic vehicle is turned off, its motor encoder does not monitor drive shaft and wheel rotation. As a result, the robotic vehicle loses track of its location when it is turned off and manually pushed. When the robotic vehicle is turned back on, the new location coordinates for the robot must be entered or other means must be used to allow the robot to determine its current location.
A still further problem with conventional robotic vehicles is that unsafe loading conditions go undetected. There is no mechanism to determine the weight of the vehicle or the items placed on it. Similarly, there is no mechanism to determine if the load is unbalanced, which could cause the vehicle to tip over when making a turn. There is also no mechanism to determine if an object is extending outwardly from the vehicle to a point where that item could hit other objects when the vehicle is moving.
A still further problem with conventional robotic vehicles is their inability to determine the types and thicknesses of materials in their field of view (FOV), distance from the radar input device, stationary or moving relative to the radar input device, and angle of movement if the material is moving in relation to the cart.
A still further problem with conventional robotic vehicles is they have difficulty sensing information about the payload on platform carts. This is due to the limited locations for sensor placement that would allow for line of sight viewing of the payload. Available locations include the platform and the handle area. Sensors located on the platform are obstructed by the payload. Sensors mounted on the rear handle are obstructed from viewing the front of the payload by the payload itself. Without being able to view the payload, the cart does not know if the payload extends beyond the platform. If the payload does extend beyond the platform, the payload will collide with obstacles as the cart autonomously moves.
A still further problem with conventional robotic vehicles is that their inability to see through or around objects. They rely on-line-of-sight sensors that provide little or no time to adjust for collisions when passing through or by a doorway or around or by a corner. For example, when a cart travels around a corner, it view of a person or object moving in the opposite direction around that corner is optically obstructed, which greatly lessens the time and distance for the cart to sense and avoid collisions.
The present invention is intended to solve these and other problems.
This invention pertains to a robotic cart platform (RCP) with a navigation and movement system that integrates into a conventional utility cart to provide both manual and autonomous modes of operation. The platform includes a housing with a processor and memory and external motorized drive wheels with encoders that replace the front wheels of the cart. The system has work environment mapping sensor and a cabled array of depth cameras, proximity or radar sensors, weight sensors, lights, control panel, battery and on/off and emergency stop buttons secured throughout the cart. The encoders obtain drive shaft rotation data and an IMU obtains three axes of angular rate and acceleration data that a microcontroller periodically sends to the processor. When in autonomous mode, the system provides navigation, movement and location tracking with or without wireless connection to a server. Stored destinations are set using its location tracking to autonomously navigate the cart. When in manual mode, battery power is off, and back-up power is supplied to the encoders, IMU and microcontroller, which continue to obtain shaft rotation data and angular rate and acceleration data. When in autonomous mode, the shaft rotation, angular rate and acceleration data obtained during manual mode is used to determine the present cart location.
An advantage of the present robotic cart platform is its ability to integrate into conventional, manually moved, utility cart designs. The components forming the robotic cart platform (RCP) includes motorized drive wheels, an RCP housing and an autonomous mapping and navigation system, environmental mapping and obstacle avoidance sensor, input components and structures that are readily installed on a conventional cart. The housing is designed to fit under the cart, which is an area not utilized for payload transport. This area also offers a substantially unobstructed 360 degree view of the surrounding environment, which makes it desirable for mounting a LIDAR sensor. Proximity or radar sensors are positioned near the corners of the cart to give them an optimal view of where the cart is moving. The front caster wheels are removed and replaced by the drive wheels. A prefabricated array of electric cables that are harnessed together at one end near their terminal ports is plugged into the RCP housing. The individual cables for the proximity or radar sensors and input devices are routed through existing channels and openings in the conventional cart. Existing openings or areas in the risers and trays are also used to mount proximity or radar sensors and lights to convert the conventional utility cart into an autonomous robotic cart. Minimal modifications to the cart are required. Businesses that use conventional, off-the-shelf, manually pushed utility carts can inexpensively convert them into autonomous mobile robotic carts.
Another advantage of the present robotic cart platform is its independent operating system. The present cart platform design has an on-board operating system and database capable of operating independently, and does not require support from an off-board operating system or server. Workers interact directly with the robotic cart to control the movements of the cart. The cost of installing an off-board server and wireless support system is avoided, allowing the benefits of robotic carts to many companies that cannot practically install a WiFi system or otherwise cannot afford a more expensive robotic cart system. In addition, the independent operation of the autonomous cart avoids the problems associated with dead zones that occur in many robotic cart systems.
A further advantage of the present robotic cart platform its compatibility with both autonomous and manual movement of the cart. First, a cart installed with the robotic platform can be manually pushed or pulled. When the drive motors are not powered, the motors allow substantially free rotation of their drive shafts, so the wheels do not drag or turn with a high amount of resistance. Workers can finely move the cart to a precise position, or move the cart when it does not have power. Second, carts installed with the robotic cart platform keep track of their location when manually pushed to a new location. Both the manual mode and the autonomous mode allow the robotic cart to independently determine its location. When power to the robot drive motors and main processor are turned off, a separate power source is activated to run its motor encoder, IMU and microcontroller, which continue to track wheel rotations and the angular rotation and acceleration of the cart to determine the location of the robotic cart. When the robotic vehicle is turned back on, the microcontroller transmits wheel and shaft rotation data to the main onboard processor to determine the current location of the robotic cart. The robotic vehicle does not lose track of its location when it is manually moved. A worker does not need to enter the new location of the cart, or otherwise require the cart to determine its new location, such as through the use of RFID tags or an off-board WiFi type operating system.
A still further advantage of the robotic cart platform is its harnessed array of cabled sensors, safety/status lights and input devices, such as the control panel, battery and on/off and emergency stop buttons. While the drive unit is located under the cart, these components are not. Cabled sensors and lights that need to be substantially unobstructed or highly visible are located in optimal locations on the cart. Input devices that would be awkward to reach and use if placed under the cart, are located at appropriate and easily accessed locations on the cart. Components such as the battery that might need to be periodically recharged or replaced are located at more easily accessible locations. The RCP drive unit circuitry has multiple power supply input terminals, so battery packs can be hot swapped while the RCP processor continues to run. There is no need to power off the RCP processor to charge the batteries. Once the particular off-the-shelf cart is selected, the appropriate harnessed array of cabled sensors is selected so that the necessary number of individual cables and cable lengths is available to hook up the appropriate components for that make and model of utility cart. The cabled sensors and input devices conform to the unique configuration of a particular cart, instead of the cart conforming to the sensors and input devices. Cable lengths are easily changed for varying carts without changing the size, configuration, mounting structures and internal components of the RCP platform.
A still further advantage of the robotic cart platform is serviceability. The cables and each of these components are replaced or upgraded without needing to replace or modify the main robotic cart platform. Each cable has ports at both its ends. To remove and replace an external component, such as a sensor, light, control panel, battery, etc., the appropriate cable simply has to be disconnected from the port of that particular external component. To replace the harnessed cable array, the ports at both ends of the cables are disconnected.
As still further advantage of the robotic cart platform is its ease of integration into a conventional cart. The cables are routed through existing channels and openings in conventional carts. The sensors and safety lights are mounted in or via existing openings in the carts. Speakers and WiFi unit are mounted inside compartments in the trays. Four external single board computers (SBCs) and two external universal serial bus (USB) hubs increase the ease of integrating the RCP into a conventional cart to produce an autonomous cart. One SBC is located in near each proximity or radar sensor and its accompanying set of LED lights to convert the communication protocols of the sensors and lights to a USB protocol. The external SBCs and USB hubs allow for easier cabling installation, reduces costs by replacing more expensive custom-made cables with USB cabling, and buffers data to reduce the real time processing burden on the internal SBC and digital board inside the RCP housing. The external SBC and USB hubs also improve manufacturability because the cabling in each post is assembled and tested as a sub-assembly, with the final assembly of the cart being performed later. Since the cart posts are the same for the larger sized and smaller sized carts, the cabling for each post can be manufactured independently of cart size. The external SBCs and USB hubs also improve reliability in that if the components in one post fail (i.e., sensors, lights, external SBC, or USB cabling), that failure will not cause the components in the other posts to fail. The external SBC and USB hubs also provide enhanced flexibility in that sensors and lights in one cart post are readily changed to other items (e.g., radar sensors) without needing to make other changes in the cart provided the software or programming of the RCP processors is capable of supporting the change.
A still further advantage of the robotic cart platform is the scanning area of its proximity. Each corner riser of the autonomous cart has four proximity sensors. Two sensors point sideward, and two sensors point forward or rearward. Two sensors are located higher up on the cart frame, and two sensors are located lower on the frame. The higher sensors are angled downwardly and the lower sensors are angled upwardly, so that the scanning cones of paired sensors intersect at about half of the cart height. Should one of the paired sensor fail, the other paired sensor will still cover the area where their scanning cones intersect. The upward angling sensors detect instances where an item placed on a cart extends out from the edge of the cart a significant distance, and a worker is alerted as this can lead to a collision of that overhanging item or an unbalanced payload. The downward angled proximity sensors more reliably detect lower height obstacles and drop offs such as stairwells, which help prevent the cart from falling into a stairwell or out of a shipping dock.
A still further advantage of the robotic cart platform is the location and scanning area of its LIDAR sensor. The sensor is located at a protected location between the drive unit and the lower tray. The LIDAR sensor peers out from between the drive unit and lower tray to scan in almost a full 360 degrees. Only the tops of the drive wheels, drive unit mounting posts and the front caster wheel assemblies obstruct the full 360 degree of view.
A still further advantage of the RCP is its weight sensors. Two weight sensors are located just above the rear caster wheel assemblies, and two sensors are located just above the RCP mounting assembly. These sensors measure the weight of the cart (not including the caster wheels or RCP). The weight measurements are used multiple ways. The cart uses the measurements to determine if an object has been placed onto or taken off of the cart. The cart also uses the weight measurements when the cart is planning its movements (e.g. will need more power for heavier payloads). The cart can also determine if the payload is exceeding a threshold and causing a safety issue, or if the payload is balanced or unbalanced. The cart will then warn a worker and use the weight information to take appropriate action, such as turn at a slow rate or stop altogether. Weight measurements and safety determinations can be performed when the cart is stationary or when it is moving. If there is a change from balanced to unbalanced while moving, the cart can act upon that to prevent the loss of the payload or to inform the user of the imbalance. Lastly, the cart detects when a person presses on the cart (like pressing a button), which is recognized as user input, such as an indication that the cart is empty.
A still further advantage of the RCP is the ability of the radar sensors to determine the type and thickness of materials in its field of view (FOV). By directing its radar devices towards the ground or floor, the RCP is not only able to better sense changes in elevation, but is also able to sense the material composition of the floor, layers of items or material on the floor surface and the ground or materials beneath the floor surface. Observing and knowing the composition of the floor surface provides information to the RCP that aids in its ability to provide better traction control. For example, when the cart moves from one surface to another, the RCP observes the change in surface, such as moving from an unfinished concrete surface to a laminated concrete surface, a tile surface or carpeting, which allows the RCP to adjust its speed and acceleration for better traction. In addition, the RCP detects liquids or discarded paper laying on the floor surface, which allows the RCP to adjust its speed and acceleration for better traction or to avoid the liquid or paper altogether.
A still further advantage of the RCP is that its radar sensors give the autonomous cart the ability to navigate through open areas that are void of obstacles by which it would otherwise triangulate its position. Moving autonomously requires the cart to be localized and to navigate the environment. Both requirements are aided by sensing obstacles in the environment from which to triangulate and determine its location. However, when the cart is in areas void of obstacles, the ability of the cart to successfully reach the destination could be hindered. The RCP uses its radar sensing devices to determine and map material patterns beneath the floor surface. The composition of the ground or materials beneath the floor surface provides landmarks and distinctive characteristics by which the cart can triangulate to determine its current location and better navigate through an allowed environment. For example, metal bolts driven into concrete flooring, embedded metal pipes or embedded metal rebarring commonly used to strengthen concrete floor slabs provide an excellent means to map the ground. Rebarring in concrete flooring is often constructed in a grid pattern. This grid pattern provides a very distinctive and regular pattern that can aid in the orientation and localization of the cart in respect to the environment. Localization enables the cart to determine its location in its internal map of the surrounding environment, and thus the ability to recognize its physical location in the actual surrounding environment. Underground wiring, conduits, piping, tunnels, and other subsurface items are also identified in the RCP map of the allowed or surrounding environment. The RCP uses its radar input device aimed downwards to sense ground and subsurface composition. The varying nature of the ground and subsurface are recorded to provide a map for the cart to localize with and then to navigate to destinations. The cart and RCP can either be manually pushed over or autonomously driven over a surface to create a map of the composition of the surface and subsurface materials. Rebarring, wiring, conduits, piping, tunnels, and other subsurface items are identified on the map.
A still further advantage of the RCP of the autonomous cart is its ability to determine the position of the payload in its trays. The radar input devices are orientated towards the trays or shelving areas where the cart’s payload is placed. This allows the RCP to determine the type of material and thickness of the payload. This information is used to calculate the mass and center of gravity of the payload along with the positioning of the payload on the cart. With this information, the cart is better able to determine how to move to avoid unwanted shifting of the payload or tipping of the cart. In addition, this information is recorded or communicated with other systems or to the user. Furthermore, calculations are done to count the number of objects as they are placed onto or removed from the cart. Radar input devices located underneath the tray or platform sense the entire payload, and allow the RCP to determine if any portion of the payload extends beyond the platform. Furthermore, when the radar input devices are aimed outward and upward from the edges of the platform, the radar input devices sense the areas of the payload which extend beyond the platform. When moving autonomously, the RCP cart can consider not only the boundaries of the cart but also the overhanging payload areas to ensure neither collide with any obstacles.
A still further advantage of the RCP of the autonomous cart is its ability to detect dynamic obstacles along with calculating their distance, direction, velocity and acceleration. While the LIDAR sensor and cameras gather and send data to the RCP processors and for calculating the velocity of moving people and objects, because the radar sensor send velocity data to the processors natively, the processors require less processing time to detect moving people and objects and the navigation and control system and autonomous cart are able to detect and respond to moving people and objects more quickly. The radar sensors calculate these measurements using what is commonly referred to as Doppler radar. The computing device or programmed processor of the RCP calculates the intersection of dynamic obstacles in relation to the cart. The RCP processors use the radar sensors to determine the distance between the cart and the stationary or moving obstacle, the angle of movement when the obstacle is moving in relation to the cart, and the speed of the cart relative to the obstacle. When an intersection is projected to occur, the cart makes navigational adjustments to avoid a collision such as altering its path, altering its speed, or applying its brakes.
A still further advantage of the RCP of the autonomous cart is its ability to sense objects that are obstructed from view. The penetrating radar of the RCP senses materials and objects behind other materials and objects. This radar allows for sensing of both static and dynamic obstacles that are hidden optically from the cart. For example, when the cart travels around a corner of a building, the radar devices sense objects moving around or past that corner, which greatly lessens the time and distance for the RCP to sense the object and avoid a collision. The penetrating radar senses through optical obstructions to detect moving objects or people near a corner or doorway to allow additional time and distance for the RCP to avoid a collision.
A still further advantage of the RCP of the autonomous cart is its ability to determine objects through which the cart can pass or go over. For example, the user can instruct the cart to travel through plastic strips hanging in a doorway, or drive over debris such as paper or liquid on the floor. By determining the material composition and thickness of obstacles, the RCP of the cart can calculate when it is expected to avoid an obstacle, or go through or over an obstacle.
A still further advantage of the RCP of the autonomous cart is its ability to classify human objects, such as a human body or body part, as different from non-human objects. The position and motion of a human body part is interpreted by the RCP as direct input by the human to the cart. This human input data is used to control the cart or to input data to the cart. For example, waving a hand signals the cart to start moving, holding up a hand signals the cart to stop moving, or holding up two fingers signals the cart to enter the number “2”, such as to start heading to the second set destination. Similarly, non-human objects can also be interpreted by the RCP computing device.
A still further advantage of the RCP of the autonomous cart is it detects when and how a worker is gripping the cart handle. Radar devices placed in the handle and orientated towards the natural grip positions detect when a person is gripping the handle. When the cart is moving autonomously and the RCP detects a worker has just gripped the handle, the RCP aborts autonomous motion. The RCP also detects the placement of the hand, fingers and thumb on the handle to allow for additional data input. For example, when a hand grips the handle, the placement of the thumb near the handle is interpreted to control the speed and direction of a drive wheel. Moving the thumb towards the front will reverse the direction of the drive wheel, while moving the thumb towards the rear causes the drive wheel move in a forward direction. The RCP interprets the placement of the thumb further away from a center point on the handle as direction to increase the speed of the drive wheel.
A still further advantage of the RCP of the autonomous cart is it allows human data input and control without direct contact with the cart. This contactless control greatly reduces the opportunity for an electrostatic discharge (ESD) event to occur. When carts travel, electrical charge can be built up on the cart. When the charge level becomes too high, an ESD will occur. When an ESD occurs, it can result in disruption of the electrical operation of the cart, which can result in permanent damage to the cart. The ESD event can also provide an unwanted shock to the human.
A still further advantage of the RCP of the autonomous cart is the location of its radar input devices. The radar input devices are installed inside or behind cart components, such as shelving, posts or handles. Depending upon the frequency, power output and receiver strength of the radar input device, proper selection of the material the device and the environment is critical. For example, 60 GHz radar passes through high-density polyethylene (HDPE) plastic with minimal signal loss and minimal degradation in signal quality. The RCP allows its radar input devices to be installed behind or inside of cart components made of HDPE plastic, so the sensing ability of the radar input devices are not significantly affected. Furthermore, the installation of the radar devices does not require the cart to be cut or modified. The non-visible interior placement of the radar input devices maintains the aesthetics of the cart. The placement of the radar sensors behind or inside of the cart components also facilitates the ease of sealing the RCP circuitry external to its housing so that these components remain water and dust proof.
Other aspects and advantages of the invention will become apparent upon making reference to the specification, claims and drawings.
While this invention is susceptible of embodiments in many different forms, the drawings show and the specification describes in detail preferred embodiments of the invention. It should be understood that the drawings and specification are to be considered an exemplification of the principles of the invention. They are not intended to limit the broad aspects of the invention to the embodiments illustrated.
Conventional manually pushed utility carts are widely used to move tools, equipment, component parts, partially or fully assembled products and associated paperwork from one room or work station to another throughout a building. An example of a conventional utility cart 2 is shown in
Conventional utility carts 2 typically have four caster wheel assemblies 14. Each caster wheel assembly 14 has a wheel 15 and a swiveling hub 16. Each hub 16 supports an axel 15a that rotatably holds its wheel 15 to allow the wheel to rotate and roll along the floor of the building. Each hub 16 also has a caster mounting structure 17 that swivelingly secures the wheel 15 and hub 16 to the cart mounting structure 8. The upper surface of the caster mounting structure 17 frequently has a central area 17c having a rounded crown 18 with an upwardly facing curved surface 18a as in
A plastic embodiment 20 of the conventional utility cart 2 is shown in
A metal embodiment 30 of the conventional cart 2 with its two front caster wheel assemblies 14 removed is shown in
The present invention pertains to a robotic cart platform system integrated into a conventional cart 2, 20, 30 to form an autonomous robotic cart or vehicle generally indicated by reference numbers 40 and 45 as shown in
The robotic cart platform or RCP 40 has a motor driven autonomous drive unit 50 shown in
The housing 51 is robustly designed to maintain its shape during use, and is formed by upper 58 and lower 59 metal portions best shown in
An adjustable mounting assembly 60 secures the autonomous drive unit 50 to the conventional utility cart 20, 30 as shown in
The cart has four weight sensor assemblies 70. Two weight sensor assemblies 70 are located directly above the mounting plates 66 of the mounting assembly 60 as shown in
The spacer plate 85 is located above the weight sensing plate 71. The spacer plate 85 has a perimeter portion 86 with fastener openings 86a, and a hollowed out center opening 88. The central opening 88 accommodates the upward flexing of the support tab 75, and provides a pathway for routing the sensor wires 82. The central weight focusing area 78 of the sensing plate 71 rides on top of and is in weight supporting engagement with mounting plate 17 (
The weight of the cart 20, 30 is supported by the central focusing areas 78 of the support tabs 75 of the four sensor plates 71. The sensor 80 is firmly secured to the semi-flexible portion or neck 77 of the sensor plate 71. The deformation of the support tab 75 by the weight of the cart 2, 20, 30 and its load causes a change in resistance in the sensors 80. The sensor 80 changes resistance when force is applied to the focal area 78 or dimple point 79 of plate 71. This change in resistance data or weight level data is sent to the visual display processor 90a or RCP processor 102 and automatically used by the processor to determine a digital weight measurement of the amount of weight carried by each sensing plate 71. The weight measurement data is then used by the higher-level functions of the visual display or RCP processor. For example, to compare the weight measurement data with a weight threshold value stored in the memory 90b, 103 to determine if the payload 29 is beyond a threshold or maximum supportable weight, or to determine if the load is balanced or unbalanced. For a balanced load, each sensor plate 71 carries a quarter of the load weight. For unbalanced loads, one or two sensors carry significantly more of the load weight than the other sensor plates. The processor then sends a digital warning message to the visual display 90 or control panel 170 (discussed below) to display a warning message via an icon on a key (such as “load capacity exceeded,” “unbalanced load” and lighting the key “red”). Although the weight sensor 80 is shown and described as being a strain gauge sensor, such as a piezoelectric sensor, it should be understood that other embodiments such as a force resistor may also be used.
The drive unit 50 has two drive motors 91 and 92 and two drive wheels 93 and 94 as shown in
The right and left motors 91 and 92 are mounted to the inside surface of the right and left sides 56 and 57 of the housing 51, respectively. The motors 91 and 92 are securely mounted by screw fasteners, so that their drive shaft or wheel axel 96 extends through the housing wheel openings 58b in side flaps 58a. The wheel axels 96 are colinear, and the drive wheels 93 and 94 are parallel to the sides 2c of the cart 2. The wheels 93 and 94 do not swivel to the right or left as do the rear caster wheels 15. Turns are taken by differing the rate of rotation or direction of rotation of the right and left drive wheels 93 and 94. The wheels 93 and 94 have a diameter of about six inches (15 cm) and are sized and positioned outside of housing 51 with their outer perimeters riding along the ground. There is preferably about 1.1 inch (2.8 cm) of clearance between the bottom 55 of the housing 51 and level ground so that the RCP 40 can traverse deviation in the ground surface. The drive wheels 93 and 94 are also sized in combination with the height of the base unit 50 and its mounting assembly 60 to ensure the cart 20, 30 is level.
When the RCP 40 is turned on or activated, the cart 20, 30, 45 is in its autonomous mode. Electric power is supplied to the motors 91 and 92, which turn their respective wheels 93 and 94 to propel the cart from one location to another along straight 47, 48 or curved 49 paths of travel. When the RCP 40 is turned off or deactivated, the cart 20, 30, 45 is in a manual mode, and power to the motors 91 and 92 is cut off. The deactivated motors 91 and 92 do not inhibit the free rotation of the drive wheels 93 and 94 so that workers can readily push or pull the cart 20, 30 from one location to another. The drive motors 91 and 92 are preferably brushless direct current (BLDC) motors with both clockwise and counterclockwise rotation connected to a planetary reduction gearbox. Each high torque electric motor 91, 92 has a length of about 6 inches (15 cm), diameter of about 3 inches (7.5 cm), rated voltage of about 24 volts, no-load speed of about 600 rotations per minute, rated torque of about 1.5 kilograms-centimeters, a reduction ratio of about ⅒ and output shaft diameter of about ¼ inch (6 mm). The output shaft 96 extends from the motor housing about 0.6 inch (15 mm), and the end of the shaft is notched to facilitate the rotationally locked securement of its associated wheel 93 or 94.
The motors 91 and 92 are interfaced to an associated dual motor controller 97. The rotational speed and direction (clockwise or counterclockwise) of each output shaft 96 is controlled by the controller 97, which is in electrical communication with motor 91 or 92 and controls the electric power supplied to each motor. The controlled power supply to each motor 91 or 92 via the motor controller 97 controls the speed of drive shaft 96 of each motor, and thus the rotational speed of the drive wheels 93 and 94. The controller 97 is preferably a brushless direct current (BLDC) motor controller with a 6.5 to 50 volt input, 350 watt brushless DC motor speed regulator control module, a 12 volt, 24 volt, 36 volt and 48 volt high power BLDC speed motor controller driver board with heat sinks and 0 to 5 volt PWM duty ratio control with an FG pulse signal and 9 pulse/round.
Each motor 91 and 92 is interfaced to an associated “always-on” encoder 98 and 99. Each encoder 98 and 99 has a rotary disk and output cable. Each rotary disk is mounted to its respective motor 91 or 92 to optically view the rotational movements of its associated motor drive shaft 96, and thus the rotational movements of its associated wheel 93 or 94. The rotary disk transmits this shaft rotational movement data or information via its output cable to the microcontroller 106 and its memory 107, which is then periodically transmitted to the RCP processer 102 and its memory 103. This shaft rotation or wheel movement data is used by the RCP processor 102 to determine the distance of travel and path of travel taken by the RCP 40 and autonomous cart 45 from its start location or start location coordinates, and to determine the coordinates or coordinated data associated with the current physical location 100 of the RCP 40 and cart 45. The high impact resistance encoders 98 and 99 preferably have a power supply of about 5 volts DC, resolution of about 400 pulses per rotation, speed of about 2400 rotations per minute, optical disk with a thickness of about 0.05 inches (1 mm), diameter of about one inch (2.5 cm) and hole diameter of about 0.47 inches (12 mm), AB 2 phase output, and line driver with ABZA-B-Z channels.
The RCP navigation and movement system 42 and drive unit 50 have circuit boards including a single board computer 101, power board 104 and digital board 105 as shown in
Data processing by the navigation and movement system 42 is handled by the programmed RCP processor 102 and microcontroller 106. The microcontroller 106 runs low level firmware that provides very fast, real time processing. The RCP processor 102 provides higher level functionality such as planning a route 149 and motor movement instructions for the RCP 40 and communicating with workers via the safety lights, control panel, audio speakers and WiFi unit, as discussed below. RCP mapping data obtained by the LIDAR sensor 140 flows from the microcontroller 106 to the main RCP processor 102. The microcontroller 106 saves mapping data in its short-term memory or DRAM 107, and then periodically conveys that data to the RCP processor 102 for storage in its long-term hard drive memory 103. Both the processor 102 and microcontroller 106 do some processing of data. For example, the microcontroller 106 use the proximity sensors 150 to scan or detect an obstacle that is present for several seconds then goes away (someone walking by). As the microcontroller 106 passes this data to the RCP processor 102, the RCP processor filters out the temporary or passing obstacle data from long term storage 103 since the obstacle 262a was more momentary and not long term like a wall, pillar or the edge of a loading dock 262. The RCP processor 102 has both associated dynamic memory, such as DRAM that is deleted from storage when power is removed, and long term hard drive memory 103 that remains stored even when power is removed.
The RCP 40 includes a portable power supply or battery pack 120 mounted to the autonomous cart 45. The battery 120 has power and communication ports 122 and 123, and supplies electric power to all the internal and external components and devices of the RCP 40 via its drive unit circuitry 109 and terminals 110. The battery pack 120 is secured to the cart 45 at a location that avoids interfering with loading and unloading the cart or impairs other activities of the workers using the cart, and allows easy access for swapping out a first battery pack with a second replacement battery pack when the first battery pack needs recharging. The power source 120 is designed to provide sufficient power to the RCP 40 for a four hour work shift and propel the cart for 500 to 1,500 meters carrying a 50 to 100 kilogram payload at a walking speed of about one meter per second. The main power source 120 is preferably a multi-cell battery pack with multiple lithium ion batteries (about 50 cells) to produce about 129.5 Wh, with each cell having a rechargeable capacity of about 4.1 volt/ 2500 mAh, a 24 volt output port and an RS-485 (two wire) communication port. The battery pack 120 is secured to the cart 20, 45 via a mounting bracket assembly 125 that includes a support bracket 126 with a slide bar 127. The slide bar 127 allows the battery pack 120 to be quickly removed for recharging and allows a fully charged battery pack to be quickly secured.
The RCP circuitry 109 includes a backup power circuit 130 on the digital board 105 as shown in
The autonomous cart 45 includes a time-of-flight laser scanner 140 as shown in
The laser scanner 140 is preferably a triangulation type laser scanner such as a LIDAR (light detection and ranging) sensor with 2D imaging, three hundred and sixty degree (360°) omnidirectional laser range, scanning range of about 12 meters, power input of about 5 volts, sample rate of about 8,000, configurable scan rate from about 2 to 10 hertz, breakout of about 940 nm and is plug-and-play, such as an RPLIDAR A2 by Slamtec. The RCP 40 uses the LIDAR scanner 140 to obtain environmental mapping data that is stored in its memory 103. The RCP 40 uses this mapping data to identify open areas 261 in the building through which the RCP 40 and cart 45 can travel, and to identify fixed structures 262 in the building through which it cannot travel. The RCP 40 uses the mapping data and current location 100 data to determine a route 149 along which the cart 45 can travel to a selected destination 172 as discussed below. (
The LIDAR scanner 140 is preferably mounted on the RCP drive unit 50 below the cart structure 3 and lower tray 21, 31. The scanner 140 is secured to the autonomous cart 45 at a location providing a substantially unobstructed 360° view or substantially circumferential sensing range of the environment 260 around the cart, is protected from inadvertent contact by workers and objects, and does not interfere with the operation of the cart or workers. A particularly good location for the 360° scanner 140 is in the middle of the top surface 54 of the drive unit housing 51, although other locations on the RCP drive unit 50 or cart 45 are possible. The rotating scanner (not shown) of the LIDAR scanner 140 is located above the drive unit mounting bracket 62, so the bracket does not obstruct the view of the scanner. Only the drive unit mounts 65 and a small portion of the rear caster wheel assemblies 14 obstruct the 360° scanning area or plane 142 of the LIDAR scanner 140 as shown in
Proximity sensors 150 are mounted on the autonomous cart 45 shown in
Multiple proximity sensors 150 are mounted to the autonomous cart 45 as shown in
For the metal autonomous cart 30, 45 (
Warning or safety lights 160 are mounted to and around the autonomous cart 45. For the plastic autonomous cart 20, 45 the lights 160 are mounted inside the riser channel 26, with each light peering from or out of a riser opening 27. Two safety lights 160 are mounted in each L-shaped riser 25. One light 160 is mounted to peer from the middle opening 27 on each side 25a and 25b of each of the four risers 25. Each riser 25 has one light 160 facing sideward 2c, and one light facing forward 2a or rearward 2b. The lights 160 are preferably LED lights that consume a minimal amount of electric power. The LED lights 160 slowly blink on and off when the cart is moving, and change color (orange) and do not blink when and obstruction is detected. Different colors can flag different situations such as purple -proximity sensor not working, white - cart is moving in that direction (headlights), red - cart is moving away (taillights) and green - all actions completed and cart is ready for another command. Each light 160 has a connection terminal for receiving electric power, and is secured inside the riser openings 27 by a mounting clip 165.
A control panel 170 or suitable device to allow a worker to communicate with the navigation and movement system 42 is mounted on the autonomous cart 45 as shown in
The communication device or control panel 170 is preferably secured to the rear side 2b of the utility tray 28 by a mounting bracket and fasteners. The panel 170 has a connection that receives a USB cable to provide electric power from the battery as well as send and receive signals, or otherwise communicate with the navigation and movement system 42, processor 102 and memory 103. The RCP memory 103 is loaded with sets 173 and 174 of icon images to selectively display on the six control keys 171. One set of icons 173 or 174 is displayed at a time on the keys. (
The 6-key control panel 170 allows the navigation and movement system 42 to perform a wide range of functions. When the RCP 40 is turned on, the RCP processor 102 displays the set 173 of destination icons on the keys 171 as shown in
The autonomous cart or vehicle 45 is programmable to stop when it gets to a desired destination 172 and wait for a worker to enter further control panel instructions, or move in a looped manner from one predetermined destination location 172 to another. For the later, once the cart 45 reaches a first desired destination 172 (“1” icon) and waits a predetermined period of time, the cart 45 goes to the next numerical predetermined destination 172 (“2” icon). Workers can change the order of the loop by resetting the particular destination 172 associated with each destination icon. Workers can delete a predetermined destination 172, and if desired replace it with another destination location 172 as noted above.
The set of arrow or movement icons 174 (
A large visible on/off switch 175 is provided on or near the control panel 170. This switch or depressible button 175 is used to turn on or activate the RCP drive unit 50 by allowing electric power from the battery 120 to energize the internal and external RCP drive unit 50 components and devices that form the RCP 40, and place the RCP 40, navigation and movement system 42 and cart 45 in an autonomous mode of operation. The switch 175 is also used to turn off or deactivate the RCP 40 by disconnecting the flow of electric power from the battery 120 to the RCP, and place it and cart 45 in a manual mode of operation. The switch 175 is mounted through a hole drilled into the cart 20 and secured by a nut on the back side. Two wires on the back of the button 175 provide its electrical connection with the system circuitry 109. An emergency stop button 180 is located at the front 2a of the cart 45. This button 180 can also be used by a worker to turn off or deactivate the RCP 40, and place it and the cart 45 in a manual mode of operation. The button 180 has a rear connection 182 for receiving a USB cable to send and receive communication signals.
The control panel 170 has a “GO” button 185. For the plastic cart 20, 45 (
The RCP 40 is equipped with an audio speaker 190 for communicating with workers. For a plastic cart 20, 45, the speaker 190 is secured in a webbing compartment 24 on the underside of the upper tray 22 (
The RCP 40, navigation and movement system 42 and autonomous cart 45 are optionally equipped with a WiFi unit 195. The WiFi unit 195 is mounted inside a webbing compartment 24 on the upper tray 22 as shown in
A cable array 200 shown in
The right 201 and left 202 lines each include multiple and separate wire lines 205 for powering and communicating with two weight sensors 80, eight proximity sensors 150 and four safety lights 160. The right line 201 also includes separate wiring lines 205 for powering and communicating with the control panel 170, On/Off switch 175, emergency stop 180 button, “GO” button 185, audio speakers 190 and WiFi unit 195. The individual wires 206 at one end of each power and communication wiring line 205 for a specific external component are connected to a component-specific connection 210 that electrically connect its wires 206 to the terminal for that external component. The individual wires 206 at the other end of each wiring line 205 are connected to an input/output connector 215 that plugs into and electrically connects the wiring line with its appropriate input/output port 111-119 of the drive unit 50. The wiring lines 205 for the proximity sensors 150 in one line 201 or 202 share a common input/output connector 215. The individual wires 205 in the two lines 201 and 202 of the cabled array 200 are harnessed 209 together near the input/output ports 111-119 and joined to their appropriate terminal 215. The appropriate terminals 215 are then plugged into their appropriate input/output port 111-119. It should be understood that the lines of the cabled array 200 can be divided into four line 201-204 as shown in
When the RCP 40 is turned on via switch 175, electric power from the battery 120 is supplied to the RCP 40 and navigation and movement system 42, which includes circuit boards and internal components 91, 92, 97-99, 101-109 and 135 as well as external components 80, 140, 150, 160, 170, 175, 180, 185, 190 and 195 via cabled array 200. When the RCP 40 is turned off, electric power from the battery 120 to the RCP 40 and its navigation and movement system 42 are turned off, except for the encoders 91 and 92, MCU 106 and DRAM 107 which remain powered by the backup circuit 130 as discussed above. When the RCP processor 102 detects that the power or charge remaining in the battery 120 is running low or meets a predetermined charge threshold value, the processor plans a route to a recharging station 259 (
Modifications are made to the conventional carts 20, 30 to integrate the RCP 40 and form the autonomous cart 45. The front caster wheel assemblies 14 are removed and replaced with the RCP drive unit 50. For the conventional plastic cart 20, four riser channel cover plates 241 are secured inside each riser 25 to enclose the inner channel 26 and house and protect the proximity sensors 150, lights 160 and cable lines 201 and 202 inside these channels. A tray cover plate 242 is secured to the bottom of the upper tray 22 to house and protect the audio speaker 190, WiFi device 195 inside the webbing chambers 24 of the upper tray, as well as the cable lines 201 and 202 extending through the walls forming it matrix of webbing chambers. Cabling holes 243 are formed in the corners of the flat tray surface 6 of the lower tray 21. A first line of web holes 244 is formed in the structural webbing 23 of the lower tray 21 to route the cables 201 and 202 in a supported manner from the rear of the RCP drive unit 50 to the front of the lower tray, as best shown in
The right and left lines 201 and 202 diverge and passes through a second line of web holes 244 along the front 2a of the lower tray 21 to the front corners 4 of the tray. The lines 201 and 202 pass through their respective holes 243 in the lower tray 21 and extend up their respective riser channel 26. Third and fourth lines of web holes 244 are formed along the sides 2c of the in the upper tray 22 to allow the right and left lines 201 and 202 to extend in a supported manner along the right and left tray sides to the rear 2b of the tray just above the rear riser channels 26. The lines 201 and 202 extend downward through these channels and pass through the tray holes to reach the two weight sensors 80 at the rear of the cart. Web holes 244 are also formed along the front of the of the upper tray 22 to allow one cable 201 to reach the emergency stop button 180 mounted in an emergency stop button opening 245 formed in the center of the front of the upper tray. Web holes 244 are also formed along the rear of the upper tray 22 to allow a cable line 201 to reach the battery 120, control panel 170, On/Off switch 175 and “Go” button 185, mounted in a GO button opening 249 formed in the center of the utility tray 28. For the conventional metal cart 30 with wire baskets 31-33, riser holes 249 are formed proximal the top and bottom ends of the tubular risers 35 to allow cable wiring to extend from the lower tray to the upper tray in a protected manner.
The RCP 40 uses its WiFi unit 195 to communicate with a separate work station 250 shown in
The computer screen of the monitor 255 also shows a list of the coordinates 265 for each listed destination. The screen provides touch screen buttons 266 and 267 to add destinations to or delete destinations from the RCP memory 103. New destination coordinates are entered via the keyboard 254. The SRCP 250 and its touch screen buttons are operable to remotely select a specific destination for the cart 45 to travel next. Then a visually displayed “GO” button 268 on the screen of the SRCP monitor 255 is pressed to remotely control the RCP 40 and send the cart 45 to that selected destination. The SRCP monitor 255 screen also visually displays a touchable joystick 269 to remotely control the operation of the RCP 40 and movement of the cart 45.
When multiple autonomous carts 45 are used, the SRCP 250 communicates with each of them. Mapping data from various carts 45 is combined to form a global map 260′ of the working environment 260 in the SRCP memories 103, which is displayed on the SRCP monitor 255 along with the current locations 100 of each cart. Data containing the master or global map of the SRCP 250 is transmitted to the memory 103 of each RCP cart 45, so that each cart learns from the other carts.
An alternate embodiment of the mounting assembly 60 is shown in
Each block 361 and 362 also has two rearward fasteners 365b to help secure the mounting plate 366 to its mounting block 361 or 362. The heads of these rearward fasteners 365b are received in recesses 368 in the bottom surface of the blocks 361 and 362. These rearward fasteners 365b also pass through holes in the base portions 363 and rear columns 364 of the blocks 361 and 362, and are received by and secured to threaded holes 367b in its mounting plate 366 to help secure the mounting plates to the drive unit 50. As with mounting assembly 60, threaded fasteners 19 are used to secure the mounting plates 366 to the support structure 8, 8a of the cart 20. The shafts 19a of these fasteners 19 pass through holes or fastener openings around the perimeter portion of the mounting plates 366, which are aligned with the fastener holes 8a of the cart mounting structure 8. Again, as with mounting assembly 60 shown in
A second embodiment of the robotic cart platform 440, navigation and movement system 442 and autonomous cart 445 are shown in
The low-profile housing 451 is robustly designed to maintain its shape during use, and has a generally rectangular box shape construction that is wider than it is tall as seen in
The housing mounting assembly 460 selectively and slidingly receives, positions and secures the housing 451 to the underside of the lower tray 21. The assembly 460 includes two metal slide rails 461 that are bolted, screwed or otherwise rigidly secured to the housing top 454 as best shown in
The housing mounting assembly 460 includes four mounting plates 462 rigidly secured to the webbing 23 on the underside of the lower tray 21 as shown in
The four flat inner sections 465 are in planar alignment and are generally parallel to and spaced from the underside of the lower cart tray 21. Each inner section 465 is located at the inner portion of its quadrant, so that the sections 465 are positioned at or proximal the middle of the lower tray 21. Each section 465 has a downwardly extending securement bar 466 shaped to selectively and slidingly receive, and firmly hold one of the slide rails 461 secured to the housing 451. The forward slide rail 461 is slidingly held by the two forward 2a housing mounting plate assemblies 460. The rearward slide rail 461 is held by the two rearward 2b housing mounting plates 462. Mounting the RCP housing 451 on rails 461 allows for quicker and easier servicing of the RCP 440. When the external components are disconnected from the RCP housing ports 110, the components and circuitry in the housing 451 are easily removed and swapped out with a replacement RPC housing and its internal components and circuitry.
The two conventional caster wheel assemblies 14 mounted at the front 2a of the cart 445 secure the two forward mounting plates 462 to the cart 20 as shown in
The drive wheel assemblies 490 are mounted external to the housing 451. The right drive wheel assembly 490a is mounted at the front 2a right corner 4 of the cart 445, and the left drive wheel assembly 490b is mounted at the front left corner of the cart. Similar to the first embodiment, the right assembly 490a includes a drive motor 491, drive wheel 493 and encoder 498, and the left assembly 490b includes a drive motor 492, drive wheel 494 and encoder 499 as shown in
Similar to the first embodiment, each motor 491 and 492 is interfaced to its associated “always-on” encoder 498 and 499. Each encoder 498 and 499 has a rotary disk and an output cable 497a. Each rotary disk is mounted to its respective motor 491 or 492 to optically view the rotational movements of its associated motor drive shaft 496, and thus the rotational movements of its associated wheel 493 or 494. The rotary disk transmits this shaft rotational movement data or information via its output cable 497a to the microcontroller 106 and its short-term memory 107, which is then periodically transmitted to the RCP processer 102 and its long-term memory 103. As with the first embodiment, this shaft rotation or wheel movement data is used by the RCP processor 102 to determine the distance of travel and path of travel taken by the RCP 440 and autonomous cart 445 from its start location or start location coordinates, and to determine the coordinates or coordinated data associated with the current physical location 100 of the RCP 440 and cart 445. The motors 491, 492 are interfaced to the associated dual motor controller 97 located inside the housing 451. The rotational speed and direction (clockwise or counterclockwise) of each output shaft 496 is controlled by the controller 97, which is in electrical communication with motor 491 or 492 and controls the electric power supplied to each motor. The controlled power supply to each motor 491 or 492 via the motor controller 97 controls the speed of drive shaft 496 of each motor, and thus the rotational speed of the drive wheels 493 and 494.
Each drive wheel assembly 490 is rigidly secured to the cart 445 by a drive wheel mount 501. Each drive wheel mount 501 has two opposed downwardly extending legs 502 that straddle the drive wheel 493 or 494. Each leg 502 has an opening 502a at its lower end to receive and firmly secure the drive shaft 496 (
The two drive wheel assemblies 490a and 490b at the front 2a of the cart 445 secure the two forward mounting plates 462 to the cart 20. The wheel mount 501 engages its respective flat corner section 463 as shown in
As noted above, the first and second embodiments of the RCPs 40, 440, navigation and control system 42, 442 and autonomous carts 45, 445 have circuit boards 97, 101, 104, 105, processors 102 and 106, memory 103 and 107 and circuitry 109. (See
The cart 445 has two conventional high resolution, 3D depth or digital cameras 550 for viewing or sensing the working environment 260 as shown in
Each camera 550 has right and left imagers, an IR projector and an RBG module. They are lightweight and suitable for indoor and outdoor use. Each camera 550 has length, depth and height dimensions of 90 mm, 25 mm and 25 mm, respectively. The cameras 550 have a wide field of view (FOV) and global shutter sensor for robotic navigation and object recognition. The global shutter sensors provide great low-light sensitivity to allow cart 445 to navigate spaces with the lights off. The cameras 550 have stereoscopic depth technology, global shutter image sensor technology, an ideal range of one to ten feet, depth FOV of 87° x 58°, depth output resolution of 1280 × 720, depth accuracy of less than 2%, RBG frame resolution of 1920 × 1080, frame rate of 30 fps, sensor FOV (H × V) of 69° × 42° and sensor resolution of 2 MP and USB-C 3.1 Gen 1 connectors. The environmental mapping data from the cameras 550 combine with the data from the LIDAR sensor 140 in the RCP processors 102 and 104 to produce a three hundred and sixty degree (360°) map 260′ of the surrounding environment 260. (See
The EZ Go Navigation control panel 570 is shown in
The control panel or communication device 570 is secured to the utility tray 28 similar to panel 170, and has a connection that receives a USB cable to provide electric power from the battery as well as send and receive signals, or otherwise communicate with RPC 440, navigation and movement system 442, processors 102, 106 and memory 103, 107. The RCP memory 103 is loaded with sets of icons 173 and 174 to selectively display on the fifteen control keys 171. As with panel 170, one set of icons 173 or 174 is displayed at a time on the keys 171 for panel 570. (
The control panel 570 has thirteen destination keys 171a to store destination coordinates 265 (e.g., X, Y coordinates 264-1, 264-2, 264-3, etc.) for up to thirteen physical destinations 172. Eleven destination keys 171a are shown in the first set of icons 173 (
Cart destinations 172 are easily set using the destination keys 171a. When the cart 445 is pushed to a specific location or destination 172 (e.g., location 172 number “2” or 172-2, see
The 15-key panel 570 also has several specialty or function keys, such as a Battery key 171b, Looping key 171c, Set Map key 171d, Home key 171h, Boomerang key 171bg and Check Engine key 171ce. The Battery key 171b displays the battery status (e.g., charge level). The Check Engine key 171ce notifies the worker of any cart running abnormalities, and will flash a code to identify the specific cart operating abnormality detected by the RCP 440, such as code “1060” to indicate that the cart is tilted. Other codes indicate the payload or items 29 exceeds the cart payload capacity, the payload is not properly balanced, the payload extends too far out from the side of the cart, etc. The individual icon images 171i shown in the individual keys 171 and their accompanying text messages or codes can and do change depending on various events and changes in operation. For example, as discussed below, once you have pressed the Save Map key 171d to save the map 260′ to the RCP memory 103, the background of the function keys 171a, 171c, 171h and 171d change from gray to green, and the text of the Save Map key 171d changes from “Active Mode” to “Fixed Mode.” (
The Looping mode key 171c enables or disables a looping function or mode of the RCP 440 and cart 445. When the looping key 171c is pressed and the background of the looping key 171c turns gray (e.g., is not illuminate), the looping mode is disabled. When looping key 171c is pressed and the background turns green (e.g., is illuminated to appear green), the looping mode is enabled. When the looping mode is enabled, the destination keys 171a that are set (e.g., 171a-1, 171a-2, 171a3, etc.) are illuminated to appear blue. Keys 171a that are not set remain grey. Then, when the user presses or selects a set (blue) destination key 171a (e.g., key 171a-2), the autonomous cart 445 uses its stored mapped location coordinates (e.g., 264-2) for that destination (e.g., 172-2) along with its current map location 263 and its environmental map 260′ to determine or plan a route 149 to navigate and travel to that set and selected destination (e.g., 172-2) as it would normally. During the time the cart 445 is determining its route 149 to a selected destination 172 (e.g., 172-2, 264-2), the cart does not move, and the selected destination key 171a (e.g., 171a-2) displays a rotating circular gif to let the user know it is determining its route. Once the route 149 is determined, the cart 445 will begin to navigate and move along its selected route 149, and the background for that destination key 171a (e.g., 171a-2) blink or flash blue. After reaching that destination 172 (e.g., 172-2, 264-2), the cart 445 waits for a predetermined or specified amount of time while determining its route 149 to the coordinates (e.g., 264-3) for the next sequential destination (e.g., 172-3), and the destination key (171a-3) for that next destination displays the rotating circle gif. The cart 445 uses its current location 100, 263 at or near (e.g., within about one meter of) its current destination (e.g., 172-2, 264-2), its environmental map 260′ and its stored mapped location coordinates 265 (e.g., 264-3) for that next sequential destination (e.g., 172-3) to plan its route 149, and navigate and travel to the next sequential destination (e.g., 172-3). While the cart 445 is traveling to the next destination 172 (e.g., 172-4) the background of the next sequential destination key (e.g., 171a-4) blinks blue. The cart 445 will skip destinations that are not set (e.g., not illuminated blue), and after the last set numerical destination is reached, the cart will go back to the first numerical destination (i.e., location “1” or 172-1). The cart 445 will continue to navigate and travel to each next set destination (e.g., in a set sequence of destinations e.g., 172-1, 172-2, ... 172-5, 172-6, ... 172-11), wait the predetermined amount of time, and then proceed to the next sequential set destination in a looping manner until the user either presses any key 171 or moves the cart (e.g., more than one meter while it is waiting at a set destination 172). This Looping mode feature allows the cart 445 to move autonomously from set destination-to-set destination all day long like a city bus would do.
The Save Map key 171d saves the data for the environmental map 260′ (i.e., environmental mapping data) to the RCP memory 103. When the autonomous cart 445 is initially brought to a facility or environment 260 (
The Home key 171h is used to localize or orient the cart 445 relative to its map 260′ of the actual environment 260. Localization enables the cart 445 to determine its location (i.e., current location data) 263 in its internal map of the surrounding environment 260′, and thus the ability to recognize its physical location 100 in the actual surrounding environment 260. Once the map 260′ has been saved to the RCP long-term memory 103, the cart 445 can occasionally become mis-localized or disoriented so that the RCP 440 cannot determine or recognize its current location 100, 263. For example, while the cart 445 is powered off with the map 260′ being previously saved, the user can move the cart. Then, when the cart 445 is powered back on (activated), the RCP 440 may not be able localize or orient itself (determine current location 100, 263 of cart 445) on its previously saved map 260′, notwithstanding encoders 498 and 499, IMU 545 and backup power circuit 130. Should this occur, the user positions the cart 445 in a designated “Home” position 172h, 264h (
As noted above, the RCP 440 uses its weight sensors 70 to determine when an object is placed on or taken off the cart 445. The RCP 440 uses these weight measurements to plan the movements of the cart 445, such as traveling in a looped manner between selected destinations 172. For example, a first worker often places items onto a cart 445 at a first location 172-1, and then sends the cart to a second location 172-2 for the items to be removed by a second worker. The second worker will then return the cart 445 back to where it came from (i.e., the first location 172-1). However, the second worker may not know where the first or starting location 172-1 is located. And, even if the second worker knows where the first or starting location 172 is located, the second worker would have to make an active choice to where to return the cart. The robotic cart platform 440 uses its navigation and movement system 442 and its weight sensors 70 to allow the autonomous cart 445 to function in a boomerang mode to resolve this problem.
The boomerang mode programming operates with or without destination keys 171a set to desired destinations 172. Table 1 below describes an example of the boomerang mode in which boomerang method 580 where destination keys 171a (e.g., 171a-1, 171a-2, 171a-3, etc.) are bound or programed to first, second, third and job activity locations 172 (e.g., 172-1, 172-2, 172-3, etc.). Table 2 below describes an alternate example of the boomerang method 590 where the control panel 570 does not have destination keys 171a, or the destination keys 171a are not programmed to set destinations (e.g., 172-1, 172-2, 172-3, etc.) or are not used to perform the method.
Boomerang method 580 uses two or more set destination keys 171a. The boomerang mode programming for processors 102, 106 is enabled 583 by pressing or touching a boomerang mode key 171bg on the control panel 570. When enabled, the cart 445 starts to record the weight of the item or items 29 placed on or taken off the cart 445 at designated destinations. A first worker adds 584 an item or items 29 to the cart 445 at the start or first job activity location 172 (e.g., 172-1) within a first designated area 172-A1. The worker can push or otherwise move the cart to a more convenient location 172-1a within the first designated area 172-A1 for placing the selected item on the cart. The cart 445 weighs the selected item(s) 29 and stores the corresponding item weight data in its memory 103, 107. The worker then presses 585 a second desired destination key 171a (e.g., 171a-2) to send 586 the cart to a second job activity location 172 (e.g., 172-2) within a second designated area 172-A2. The worker can push or otherwise move the cart to a more convenient location 172-2a within the second designated area to facilitate removing the selected item from the cart. At the second job activity location 172 or 172-A2 (e.g., 172-2 or 172-A2), a second worker removes 587 item(s) 29 from the cart 445. When the item(s) 29 is removed, the cart 445 will sense the removal of the item(s) by the weight of the cart payload via its weight sensors 70, and determine if the removed item weight data corresponds to the added item weight data, and after confirming the added and removed weight data correspond (e.g., are substantially equal) and waiting a set amount of time (e.g. 30 seconds) the cart will automatically determine and navigate 588 along a return path 149b to the previous designated location where the payload weight was increased (e.g., 172-1). When the cart 445 is in boomerang mode, the worker can also press 589 the looping key 171c to enable the looping mode programming, so that the cart will continue to go back-and-forth in a looped manner between the original boomerang location 172-1bg and set destination 172-2.
581
581
a
581
b
581
c
582
583
584
584
a
584
b
585
586
586
a
587
587
a
587
b
588
589
The alternate boomerang method 590 does not require or use set destination keys 171a bound to set destinations 172 (e.g., 172-1, 172-2, 172-3, etc.). Two examples demonstrate the usefulness of boomerang method 590. In the first example, the cart 445 is brought to a storage location for the cart in a storage area of the warehouse 260 and activated via switch 175 and the boomerang mode programming is enabled by pressing the boomerang key 171bg. An item(s) 29 is then removed from a storage area, and added to the cart, which uses its weight sensors 70 to determine the weight of the item and that the item was added at this storage location, which becomes the first boomerang location (e.g., 172-1bg) saved in the cart memory 103, 107. The cart 445 is then pushed to a packing location, where the item(s) 29 is removed from the cart, which uses its weight sensors 70 to determine the weight of the removed item at this packaging location, which becomes the second boomerang location (e.g., 172-2bg). Then, the RCP 440 automatically sends the cart 445 for obtaining another item(s) 29 from storage. In the second example, the cart is pushed to and items 29 (e.g., tools and test fixtures) are taken from several storage areas (e.g., 172-1bg and 172-2bg) and placed on the cart 445. The cart 445 is then pushed to a subsequent location where a certain job using the tools and test fixtures is performed (e.g., 172-3bg). Once the job has been completed, the tools and fixtures need to be returned to their proper storage locations (e.g., 172-1bg and 172-2bg). In both of these examples, the worker at the second or later location may not know where to send the cart 445 for more items or where to return the items. When boomerang mode programming is enabled via boomerang key 171bg, the RCP 440 automatically sends the cart 445 for more items from storage, or returns the tools to their storage locations.
Table 2 below describes the alternate boomerang method 590 in which the cart 445 does not have or does not use set destinations 172 (e.g., 172-1, 172-2, 172-3, etc.) stored in its memory 103. Again, the boomerang mode programming for processers 102, 106 is enabled by pressing or touching 593 the boomerang mode key 171bg on the control panel 570. When the boomerang mode 590 is enabled, the cart 445 records the locations 172 to which it goes while the boomerang mode is enabled, and also records the weight of the item(s) 29 added to (i.e., placed on) or taken off the cart 445 at these locations 172 (e.g., first and second boomerang locations). An item 29 is added 594 to the payload of the cart 445 at the start or first boomerang location 172-1bg, and the cart senses the addition of the item in the weight of the cart payload 29 via its weight sensors 70, and stores the second boomerang location (e.g., 264-2bg) and the item weight data corresponding to the second boomerang location. The cart 445 is then pushed 595 to a second boomerang location where the item is removed 596 from the cart. After a set amount of time (e.g. 30 seconds), the cart 445 will automatically return 597 to the first boomerang location (e.g., 172-1bg) where the payload weight was last increased or decreased. When the cart 445 is in boomerang mode, the worker can also press 599a the looping key 171c to enable the looping mode programming, so that the cart will continue to go back-and-forth in a looped manner between the original boomerang location and subsequent locations (e.g., 172-1bg, then 172-2bg, then 172-1bg, then 172-2bg, etc.).
591
591
a
591
b
592
593
594
594
a
594
b
595
596
596
a
596
b
596
c
597
598
599
599
a
While not shown in a table, it should be understood that the boomerang mode programming can include first second and subsequent boomerang locations (e.g., 172-1, 172-2, 172-3, etc., or 172-1bg, 172-2bg, 172-3bg, etc.). At the subsequent or job activity location 172 (e.g., 172-3, 172-4, etc., or 172-3bg, 172-4bg, etc.) when another item(s) 29 is added to or removed from the cart 445, the cart senses the addition or removal of the item(s) in the weight of the cart payload 29 via its weight sensors 70, stores each subsequent location (e.g., 264-1bg, 264-2bg, 264-3bg, etc.) and the item weight data corresponding to each subsequent location. After the cart reaches a final destination location while in boomerang mode, and after waiting a set amount of time (e.g. 30 seconds), the cart 445 will automatically return in reverse order to the subsequent locations, second location and start location (e.g., 172-3bg, then 172-2bg, then 172-1bg) where the payload weight was last increased or decreased. Again, when the cart 445 is in boomerang mode, the worker can press the looping key 171c to enable the looping mode programming, so that the cart will continue to go back-and-forth in a looped manner between the original boomerang location and subsequent locations (e.g., 172-1bg, then 172-2bg, then 172-3bg, then 172-2bg, then 172-1bg, then 172-2bg, etc.).
The external SBCs 611 and USB hubs 615 allow for easier cabling 610 installation, reduce costs by replacing more expensive custom-made cables with USB cabling, and buffers data to reduce the real time processing burden on the internal SBC 101 and digital board 105. The external SBCs 611 and USB hubs 615 also improve manufacturability because the cabling 610 in each line or post 25 is assembled and tested as a sub-assembly, with the final assembly of the cart 445 being performed later. Since the cart posts 25 are the same for the larger sized and smaller sized carts 445, the cabling 610 for each post is manufactured independently of cart size. The external SBCs 611 and USB hubs 615 also improve reliability because should the components in one line or post 25 (i.e., sensors 150, lights 160, SBC 611, or USB cabling 610) fail for any reason, that failure will not cause the components in the other lines or posts to fail. The external SBCs 611 and USB hubs 615 also provide enhanced flexibility in that sensors 150 and lights 160 in one line or cart post 25 are readily changed to other items (e.g., radar sensors 640) without needing to make other changes in the cart 445 provided the software or programming of the RCP 440 is capable of supporting the change.
The radar version of the RCP 440 and autonomous cart 445 preferably has several conventional radar sensors or radar input devices 651-656. Each radar sensor or device 651-656 is mounted to point in a specific aimed direction 658 so that its scanning cone 659 faces that specific desired direction as shown in
Each radar sensor 640 transmits radio waves at certain frequencies to penetrate, reflect and refract through and off of material objects (e.g., walls, floor surfaces, curtains, payload items, etc.) and back to that radar sensor. Each device 640 senses the global environment 260 (via working environment data) surrounding the cart 445 including various materials and humans in proximity 260a (local environment data) to the cart. In the present version, each radar input device 640 has a preferred vertical and horizontal FOV of one hundred and twenty degrees (120°). While the present version includes multiple radar sensors 640, each having a FOV facing a particular direction, it should be understood that the broad aspect of the invention would include a single radar input device having a wider FOV such as 360°.
Each radar input device 640 has a preferred radar frequency of 60-64 gigahertz (GHz), to allow the radar to penetrate or see through various materials commonly found in manufacturing, office, restaurant, or other workplace settings, such as plastic, cloth fabric, plaster, drywall wood, metal, concrete, brick, wiring conduit, liquids such as water, humans, etc. Each radar device 640 has a resolution of 3.75 centimeters, and a range of 20 centimeters to a maximum distance of 100 to 400 meters. The radar devices 640 sense or pick up moving items natively so that sensing and determining the speed of a walking or running person or a fast or slow moving forklift is highly detectable. While the LIDAR sensor 140 and cameras 550 gather and send data to the processors 102 and 106 for calculating the velocity of moving people and objects 262a, because the radar sensors 640 send velocity or moving object data regarding moving objects 262m (e.g., walking person, other moving carts 445, etc.) to the processors natively, the processors require less processing time to detect moving objects 262m and moving people 262p and the navigation and control system 442 and cart 445 are able to detect and respond to moving objects and people more quickly.
Each radar sensor 640 is mounted to a specific location on the cart 445 and is oriented to sense a desired FOV direction and region (e.g., volume) of the sensing environment 260. Each device 640 gathers a stream of radar input data from the environment 260 in its FOV region. The RCP computing device (e.g., programmed processors 102, 106) processes the stream of radar input data from the devices 640 to characterize voxels (i.e., cubic portions of space) by material type, material thickness, distance from the radar input device, stationary or moving relative to the radar input device, and angle of movement when the material is moving in relation to the cart 445. From this characterized data or radar sensor data (e.g., working environment data, local environment data, moving object data) further calculations are done by the computing device 102, 106 to create a three-dimensional map 260′ of the surrounding environment 260. Some of the voxels in the map 260′ are open and do not contain any objects or materials, and other voxels are occupied with objects or materials.
The radar sensors 651-654 directed towards the ground 1 sense changes in elevation and the material composition of the surface 1a and ground or subsurface 1b beneath the cart 445. The RCP 440 uses the surface 1a composition beneath the cart 445 to aid in traction control for the cart 445. One or more downwardly directed radar sensors 651-654 determine the flooring 1 material type and possibly if its surface 1a has a coating (e.g., epoxy, oil, water, etc.). The RCP 440 uses flooring type and coating data to slightly adjusts how the cart 445 accelerates or decelerates. The radar sensor data also includes the composition of the ground surface 1a (ground surface data) and subsurface 1b (subsurface data) to provide landmarks and distinctive characteristics 1c (e.g., metal bolts driven into concrete flooring, embedded pipes, embedded metal rebaring grid patters, etc.) to obtain current location data by which the cart 445 localizes and navigates, and aid in the orientation and localization of the cart 445 with respect to the environment 260. (See
When the cart 445 is pushed or autonomously driven over the ground or floor surface 1a, the environmental mapping data from the radar sensors 640 (and preferably the LIDAR sensor 140 and cameras 550) is used by the programmed processors 102, 106 to create an internal map 260′ of the surrounding environment 260. The environmental map 260′ includes working environment data from radar sensors 651-654 regarding the composition of the surface 1a, subsurface materials 1b and subsurface items, patterns or anomalies 1c. (see
Moving autonomously requires the RCP 440 and cart 445 to be localized 100, 263 to navigate the environment 260, 260′. Both localization 100, 263 and navigation are aided by sensing fixed structures 262 or obstacles 262a in the environment 260 from which the RCP 440 will triangulate the real-time physical and mapped location 100, 263 (current location data) of the cart 445. This is easily achieved when the cart 445 is in open areas 261 near (in sensor range) 261a of fixed obstacles 262 that its line-of sight or visual sensors 140, 150 or 550 can detect. When the cart 445 is in open areas 261 void of (out of visual sensor range) 261b fixed obstacles 262, the RCP 440 uses the downwardly aimed radar sensors 651-654 to sense ground surface 1a and subsurface 1b composition (e.g., surface and subsurface data), including any subsurface patterns, structural anomalies or markers (e.g., rebaring, pipes, metal markers, etc.) 1c. The varying nature of the ground surface 1a (including grooves, surface markers, undulation patterns in or on the surface), subsurface 1b composition and subsurface patterns or structural anomalies 1c are recorded in the RCP long term memory 103 to provide a map 260′ from which the RCP 440 of the cart 445 will obtain current location data to localize 100, 263 and then navigate to a desired destinations 172, 264.
In addition to sensing the surrounding environment 260 of the cart 445, two radar sensors 655 and 656 are orientated towards the shelving or trays 21, 22 that support the payload items 29, as well as towards the payload areas or regions 21a and 22a above the trays where the payload items are placed. These radar devices 655 and 656 scan the shelving and payload areas, and send material type and dimension information (i.e., radar sensor item data) to the RCP 440 so it can determine the type of material and thickness of the payload items 29. This material and thickness information is used by the RCP 440 processor 102 to calculate the mass, weight and center of gravity of the payload 29 along with the position of the payload items on the shelving 21, 22 of the cart 445. The RCP 440 uses the center of gravity and payload 29 position information to better determine its navigation movements to avoid unwanted shifting of the payload 29 or tipping of the cart 445. The RCP 440 also records this radar voxel information in its long or short term memory 103, 107 or communicates this information via other systems (e.g., SBC 101. SRCP 250, etc.) or to the user via its control panel keys 171, audio speakers 190. wifi 195, etc.). The RCP 440 also uses the radar voxel information from these radar input devices 655 and 656 to perform calculations that count the number of payload objects 29 as they are placed onto or removed from the cart 445.
The radar sensors 655 and 656 located under the upper and lower trays 21 or 22 sense the entire payload 29, and when any portion of the payload extends beyond the lip or perimeter 7 of the tray. By viewing the payload 29, the RCP 440 determines if the payload extends beyond the perimeter 7 of the tray 21 or 22, and if the payload will collide with stationary or moving obstacles 262, 262a, 262m, 262p (e.g., walls, shelving, furniture, doorways, other carts, people, etc) as the cart 445 autonomously moves. The radar input devices 651-654 are aimed outward and upward from the outer edges or perimeter 7 of the tray or supporting platform 22, so that they sense the areas of the payload 29 extending outwardly and upwardly from the tray. When moving autonomously, the RCP 440 considers not only the dimensions of the cart 445, but also the portions of the payload 29 hanging outwardly from or extending upwardly from the cart to ensure neither collide with any obstacles 262, 262a, 262m, 262p.
The RCP 440 detects dynamic obstacles 262a, 262m, 262p (e.g., moving forklifts, moving people, other moving carts, etc.), and calculates their distance, direction, velocity, and acceleration (distance, direction, velocity and acceleration data). The radar devices 640 of the RCP 440 are capable of gathering Doppler radar information or moving object data to calculate these measurements. The RCP processor 102, 106 calculates the intersection of dynamic obstacles 262a, 262m, 262p in relation to the navigation path 149 of the cart 445. When the RCP 440 uses the radar moving object data to calculate that a projected intersection or collision will occur along its navigation path 149, the RCP 440 takes measures to avoid that collision, such as by altering the navigation path 149a of the cart 445, altering the speed of the cart, stopping the cart for a predetermined time, or applying a cart braking force by energizing the hub wheel motors 491, 492 to hold the drive wheel 493, 494 stationary.
The radar devices 640 sense materials and objects behind other materials and objects. This allows the RCP 440 to sense both static 262 and dynamic 262a, 262m, 262p obstacles that are otherwise optically hidden from the cart 445 (i.e., not sensed by its line-of-sight sensors). For example, when the cart 445 travels by or around a corner 262c or through or past a doorway 262dw, as shown in
The radar sensors 640 also allow the cart 445 to go through or over certain obstacles along the navigation path 149 of the cart. For example, the radar sensors 640 can detect a thin flexible lightweight material, such as thin one-eighth inch (⅛”) transparent plastic strips 262ps hanging in a doorway 262dw (
The RCP 440 classifies human and human body part 262p (via human body part data for faces, hands, fingers, etc.) as being different from non-human objects (via non-human body part data for objects such as walls, furniture, shelving, etc). The positioning and motion of human body parts are then interpreted as direct input (human body part positioning and motion data) to the cart 445 from a human. The RCP 440 can also be programmed to identify and respond to the shape or movement of certain non-human objects (non-human object shape and movement data). The RCP 440 is programmed or set to use human body input data (e.g., hand input data, finger input data, etc.) to control the cart 445 or to input a series of data to the cart. For example, the RCP 440 is programmable to direct the cart 445 to identify and move or otherwise respond to a person waving his or her hand, holding up a hand to stop the cart from moving, or entering a number by a person holding up a finger or fingers.
Another aspect of the RCP 440 is that one or more radar device 651 is placed in the handle 12 of the cart 445 and orientated towards the natural hand positions by a user when gripping the handle to detect when a person has gripped the handle. When the RCP 440 of an autonomously moving cart 445 determines a person 262p is gripping its handle 12, the RCP aborts any autonomous motion such as movement of the cart along a navigation path 149. Furthermore, the RCP 440 uses the radar devices 651 to detect the placement of the hand, fingers and thumb on the handle 12 to allow for additional data input. For example, when a human hand grips the handle 12, the placement of the thumb near the handle is interpreted to control the speed and direction of a drive wheel 93, 94. Extending the thumb forward, towards the front 2a of the cart 445, instructs the cart 445 to move forward by having drive wheels 93, 94,493, 494 rotate in a forward or clockwise rotation. Extending the thumb rearward away from cart (toward human) instructs the cart 445 to move backward by reversing the rotation (counterclockwise) of the drive wheels. The RCP 440 is programmed to determine how far away the thumb is from a center point (i.e., axis of grip area of handle), and interprets a greater distance from this center point as an instruction to increase the speed of the drive wheels 93, 94, 493, 494.
The RCP 440 also allows a user to control the cart 445 via human data input without direct contact by the human with the cart, which reduces the opportunity for electrostatic discharge (ESD) events to occur. When the cart 445 travels, electrical charge will build up on the cart. When the level of this charge becomes sufficiently high, an ESD can occur. When an ESD occurs, it can result in disruption of the electrical operation of the RCP 440 and cart 445, which can result in permanent damage to the cart, and provide an unwanted shock to the human.
Radar input devices 640 are installed behind or inside of cart 445 components, such as its shelving 21, 22, riser posts 25, or handles 12. The frequency, power output and receiver strength of the radar input device 640 are selected based on the cart component material residing between the environment 260 and the radar input device. For example, many components of conventional carts 20 are made of high density polyethylene (HDPE) plastic, and 60 GHz radar passes through HDPE plastic with minimal signal loss and minimal degradation in signal quality. The radar input devices 640 are installed behind or inside these HDPE components without affecting the sensing abilities of the radar input devices. Furthermore, secondary installation operations to the conventional cart 20 (e.g., cutting or modifying the cart) are not needed, which maintains the intended aesthetics of the cart.
When a radar input device 640 is mounted to the cart 445 near any material that covers the radar input device, the distance between the device and material is important. The ideal distance is one half of the wavelength of the operating frequency for the radar device 640. For example, for a 60 GHz radar input device 640, the wavelength is approximately 5 millimeters. Thus, one half of this wavelength is 2.5 millimeters. The radar input device 640 are located 2.5 millimeters away from the covering material of the cart 445. The shape of the covering material is also selected to minimize the reflection and refraction of the radar signal. When performing calculations utilizing the radar input device 640 data, these characteristics are considered.
While the invention has been described with reference to preferred embodiments, it will be understood by those skilled in the art that various changes may be made and equivalents may be substituted without departing from the broader aspects of the invention.
| Number | Date | Country | |
|---|---|---|---|
| 63474480 | Aug 2022 | US | |
| 62921504 | Jun 2019 | US |
| Number | Date | Country | |
|---|---|---|---|
| Parent | 16807032 | Mar 2020 | US |
| Child | 18113758 | US |
