Patent Application
20190257923
The present disclosure is directed generally to unmanned movable apparatuses, and more specifically, to unmanned aerial vehicles with optoelectronic scanning modules, and associated components, systems and methods.
With their ever increasing performance and lowering cost, unmanned aerial vehicles (UAVs) are now extensively used in many fields. Representative missions include crop surveillance, real estate photography, inspection of buildings and other structures, fire and safety missions, border patrols, and product delivery, among others. To improve flight safety as well as the user's experience (e.g., by making flight controls easier), it is important for UAVs to be able to detect obstacles independently and/or to automatically engage in evasive maneuvers. Laser radar (LIDAR) is a reliable and stable detection technology because it is able to function under nearly all weather conditions. However, traditional LIDAR devices are typically expensive and heavy, making most traditional LIDAR devices unfit for UAV applications.
Accordingly, there remains a need for improved techniques and systems for implementing LIDAR scanning modules carried by UAVs and other objects.
The following summary is provided for the convenience of the reader and identifies several representative embodiments of the disclosed techniques. An unmanned aerial vehicle (UAV) apparatus in accordance with a representative embodiment includes a main body, a scanning element carried by the main body, and a motion mechanism coupled between the main body and the scanning element. The motion mechanism is operable to rotate the scanning element relative to the main body about a spin axis. The scanning element can include a light emitting module positioned to emit light. The scanning element can further include a light sensing module positioned to detect a reflected portion of the emitted light. The scanning element can further include an optical structure coupled to the light emitting module and positioned to increase a beam height of the emitted light while generally maintaining a beam width of the emitted light.
In some embodiments, the light sensing module includes a number of light sensors, and the number of light sensors in the light sensing module can be greater than a number of light emitters in the light emitting module. Some embodiments provide that a heightwise field of view of an individual light sensor included in the light sensing module can be narrower than the increased beam height of the emitted light.
Depending on the embodiment, the optical structure can include a plano concave cylindrical lens. The optical structure can further include a plano convex lens situated between the plano concave cylindrical lens and the light emitting module. In various implementations, a flat side of the plano convex lens can face toward the light emitting module. Additionally, a flat side of the plano concave cylindrical lens can also face toward the light emitting module. According to one or more embodiments disclosed herein, the plano convex lens, the plano concave cylindrical lens, and the light emitting module can be positioned to cause a virtual image point of the light emitting module, formed from the plano convex lens, to fall within a distance corresponding to a rear focal distance of the plano concave cylindrical lens.
In one or more embodiments, a heightwise beam angle of the emitted light is increased by the optical structure from about 1 to 2 degrees to more than 30 degrees. In a number of implementations, a heightwise beam angle of the emitted light is increased by the optical structure by 10 times, and in some examples, more than 30 times. In some variations, a heightwise beam angle of the emitted light is increased by the optical structure from about 1 degree to about 33 degrees, and the a widthwise beam angle of the emitted light is to remain about less than 2 degrees. According to certain embodiments, a heightwise field of view of an individual light sensor included in the light sensing module is about 10 degrees. The heightwise fields of view of multiple light sensors included in the light sensing module can be arranged so as not to overlap each other, for example.
In some examples, the scanning element is coupled to an actuator to spin continuously at a generally constant rate. For example, the scanning element can be coupled to an actuator to spin at approximately 10 to 20 revolutions per second. The scanning element includes a scanner, which can be a light detection and ranging (LIDAR) system. The LIDAR system can include, for example, a semiconductor laser diode configured to emit light at a pulse rate of approximately 1000 Hz or 3600 Hz. In some implementations, the LIDAR system includes a single-line laser emitter.
The scanning element can further include a scanning platform that carries the scanner. In various examples, the scanner is configured to perform a terrestrial survey, obstruction detection, or a combination thereof. Further, the UAV can include a controller with instructions that, when executed, maneuver the UAV in response to terrain or an obstacle detected by the scanner. The light emitting module, in certain embodiments, can include an infrared (IR) light emitting diode (LED), and the light sensing module can include a photodiode.
In a number of embodiments, the light sensing module includes an array of light sensors. The vehicle can further include a controller configured to estimate a first distance between the vehicle and a detected obstacle based on output from a select one (e.g., the centermost) light sensor among the array of light sensors. Then, the controller can adjust a sensitivity of one or more light sensors based on the estimated first distance. In particular embodiments, a sensitivity for a light sensor located closer to an edge of the array of light sensors can be increased.
In one or more embodiments, the scanning element is weight balanced relative to the spin axis.
Several embodiments of the present disclosure also include a controller configured to maneuver the vehicle in response to the terrain or an obstacle detected by a sensor carried by the scanning element. Some of the embodiments disclosed herein can further include a plurality of thrusters carried by the main body and positioned to maneuver the vehicle in response to inputs from the controller. The plurality of thrusters can include airfoils, e.g., four propellers.
Further, in a number of examples, the vehicle includes a radio frequency module configured to receive scanning commands from a remote controlling device.
Still a further embodiment includes a method of manufacturing any and all combinations of the devices described above.
It is important for unmanned aerial vehicles (UAVs) to be able to independently detect obstacles and/or to automatically engage in evasive maneuvers. Laser radar (LIDAR) is a reliable and stable detection technology because LIDAR can remain functional under nearly all weather conditions. However, traditional LIDAR devices are typically expensive and heavy, making most traditional LIDAR devices unsuitable for UAV applications.
Accordingly, the present technology is directed to techniques for implementing an optoelectronic scanning module (e.g., a LIDAR module) that is lighter weight and less expensive than the traditional LIDAR modules, and yet can still produce the same or similar advantages (e.g., high precision, and all-weather operation) as the traditional LIDARs. Example embodiments of the various techniques introduced herein include an optoelectronic scanning module that can be carried by an unmanned movable object, such as a UAV. The scanning module can include a light emitting module positioned to emit light, and a light sensing module positioned to detect a reflected portion of the emitted light. The scanning module further includes an optical structure coupled to the light emitting module. The optical structure is positioned to increase a beam height of the emitted light while generally maintaining a beam width of the emitted light. Moreover, a motion mechanism can be located between the body of the UAV and the scanning module. The motion mechanism can be operable to rotate the scanning module relative to the airframe about a spin axis, so that the scanning module can perform 360 degree horizontal scans.
In the following description, the example of a UAV is used, for illustrative purposes only, to explain various techniques that can be implemented using a LIDAR scanning module that is cheaper and lighter than the traditional LIDARs. In other embodiments the techniques introduced here are applicable to other suitable scanning modules, vehicles, or both. For example, even though one or more figures introduced in connection with the techniques illustrate a UAV, in other embodiments, the techniques are applicable in a similar manner to other type of movable objects including, but not limited to, an unmanned vehicle, a hand-held device, or a robot. In another example, even though the techniques are particularly applicable to laser beams produced by laser diodes in a LIDAR system, other types of light sources (e.g., other types of lasers, or light emitting diodes (LEDs)) can be applicable in other embodiments.
In the following description, numerous specific details are set forth to provide a thorough understanding of the presently disclosed technology. In other embodiments, the techniques introduced here can be practiced without these specific details. In other instances, well-known features, such as specific fabrication techniques, are not described in detail in order to avoid unnecessarily obscuring the present disclosure. References in this description to “an embodiment,” “one embodiment,” or the like, mean that a particular feature, structure, material, or characteristic being described is included in at least one embodiment of the present disclosure. Thus, the appearances of such phrases in this specification do not necessarily all refer to the same embodiment. On the other hand, such references are not necessarily mutually exclusive either. Furthermore, the particular features, structures, materials, or characteristics can be combined in any suitable manner in one or more embodiments. Also, it is to be understood that the various embodiments shown in the figures are merely illustrative representations and are not necessarily drawn to scale.
Several details describing structures or processes that are well-known and often associated with UAVs and corresponding systems and subsystems, but that can unnecessarily obscure some significant aspects of the disclosed techniques, are not set forth in the following description for purposes of clarity. Moreover, although the following disclosure sets forth several embodiments of different aspects of the present disclosure, several other embodiments can have different configurations or different components than those described in this section. Accordingly, the introduced techniques can have other embodiments with additional elements or without several of the elements described below.
Many embodiments of the present disclosure described below can take the form of computer- or controller-executable instructions, including routines executed by a programmable computer or controller. Those skilled in the relevant art will appreciate that the introduced techniques can be practiced on computer or controller systems other than those shown and described below. The techniques introduced herein can be embodied in a special-purpose computer or data processor that is specifically programmed, configured or constructed to perform one or more of the computer-executable instructions described below. Accordingly, the terms “computer” and “controller” as generally used herein refer to any data processor and can include Internet appliances and handheld devices (including palm-top computers, wearable computers, cellular or mobile phones, multi-processor systems, processor-based or programmable consumer electronics, network computers, mini computers and the like). Information handled by these computers and controllers can be presented at any suitable display medium, including a liquid crystal display (LCD). Instructions for performing computer- or controller-executable tasks can be stored in or on any suitable computer-readable medium, including hardware, firmware or a combination of hardware and firmware. Instructions can be contained in any suitable memory device, including, for example, a flash drive, USB device, and/or other suitable medium.
The terms “coupled” and “connected,” along with their derivatives, can be used herein to describe structural relationships between components. It should be understood that these terms are not intended as synonyms for each other. Rather, in particular embodiments, “connected” can be used to indicate that two or more elements are in direct contact with each other. Unless otherwise made apparent in the context, the term “coupled” can be used to indicate that two or more elements are in either direct or indirect (with other intervening elements between them) contact with each other, or that the two or more elements co-operate or interact with each other (e.g., as in a cause and effect relationship), or both.
For purposes of discussion herein, the terms “horizontal,” “horizontally,” “vertical,” or “vertically,” are used in a relative sense, and more specifically, in relation to the main body of the unmanned vehicle. For example, a “horizontal” scan means a scan having a scan plane that is generally parallel to the plane formed by the main body, while a “vertical” scan means a scan having a scan plane that is generally perpendicular to the plane formed by the main body.
The moveable object 110 can include a main body 111 (e.g., an airframe) that can carry a payload 120, for example, an imaging device or an optoelectronic scanning device (e.g., a LIDAR device). In particular embodiments, the payload 120 can be a camera, for example, a video camera and/or still camera. The camera can be sensitive to wavelengths in any of a variety of suitable bands, including visual, ultraviolet, infrared and/or other bands. In still further embodiments, the payload 120 can include other types of sensors and/or other types of cargo (e.g., packages or other deliverables). In many of these embodiments, the payload 120 is supported relative to the main body 111 with a carrying mechanism 125. The carrying mechanism 125, in some embodiments, can allow the payload 120 to be independently positioned relative to the main body 111. For instance, the carrying mechanism 125 can permit the payload 120 to rotate around one, two, three, or more axes. In other embodiments, the carrying mechanism 125 can permit the payload 120 to move linearly along one, two, three, or more axes. The axes for the rotational or translational movement may or may not be orthogonal to each other. In this way, when the payload 120 includes an imaging device, the imaging device can be moved relative to the main body 111 to photograph, video or track a target.
In some embodiments, the payload 120 can be rigidly coupled to or connected with the movable object 110 such that the payload 120 remains generally stationary relative to the movable object 110. For example, the carrying mechanism 125 that connects the movable object 110 and the payload 120 may not permit the payload 120 to move relative to the movable object 110. In other embodiments, the payload 120 can be coupled directly to the movable object 110 without requiring the carrying mechanism 125.
One or more propulsion units 130 can enable the movable object 110 to take off, land, hover, and move in the air with respect to up to three degrees of freedom of translation and up to three degrees of freedom of rotation. In some embodiments, the propulsion units 130 can include one or more rotors. The rotors can include one or more rotor blades coupled to a shaft. The rotor blades and shaft can be rotated by a suitable drive mechanism, such as a motor. Although the propulsion units 130 of the moveable object 110 are depicted as propeller-based and can have four rotors (as shown in
The movable object 110 is configured to receive control commands from the control system 140. In the embodiment shown in
The optoelectronic scanning module 150 can include a scanning platform 152 carrying a light emitting module 154 and a light sensing module 156. The light emitting module 154 is positioned to emit light, and the light sensing module 156 is positioned to detect a reflected portion of the emitted light. In many implementations, the optoelectronic scanning module 150 is a LIDAR module, and the light emitting module 154 includes a semiconductor laser diode (e.g., a P-I-N structured diode). The light sensing module 156 can include photodetectors, e.g., solid state photodetectors (including silicon (Si)), avalanche photodiodes (APD), photomultipliers, or combinations of the foregoing. In some implementations, the semiconductor laser diode can emit a laser light at a pulse rate of approximately 1000 Hz or 3600 Hz.
In various embodiments, the scanning module 150 can perform a three-dimensional (3D) scanning operation, covering both horizontal and vertical directions, in order to detect obstacles and/or to conduct terrestrial surveys. Objects that can be detected typically include any physical objects or structures such geographical landscapes (e.g., mountains, trees, or cliffs), buildings, vehicles (e.g., aircraft, ships, or cars), or indoor obstacles (e.g., walls, tables, or cubicles). Other objects include live subjects such as people or animals. The objects can be moving or stationary.
In the vertical plane, in order to cover potential obstacles at different altitudes, one approach is to use multiple laser beams, with each laser beam configured to cover obstacles at a different altitude.
Techniques introduced below implement an optoelectronic scanning module (e.g., a LIDAR module) that is lighter weight and less expensive than the traditional LIDAR modules, and yet still produces the same or similar advantages (e.g., high precision, and all-weather operation) as the traditional LIDARs.
More specifically, as will be described in more detail below, the techniques in accordance with the present technology can utilize a beam divergent property of a laser diode on different planes. Therefore, the disclosed embodiments can include an optical structure for controlling the shape of a laser beam in different axial directions, such that the laser beam can have a relatively large beam height while generally maintaining the beam's width. In some embodiments, the increased beam angle in the vertical (height) direction can exceed 30 degrees. For the horizontal direction, the same spinning device (e.g., the electric motor 226a) can be used to rotate the scanning module in order to complete a 360° scan in a horizontal plane. In this way, the need for a multi-line laser emitter (e.g., emitters 254a-254d) to achieve a 3D coverage is greatly reduced or even completely eliminated, thereby greatly reducing the cost, the weight, as well as the structural complexity for implementing a LIDAR scanning module on a UAV system. Embodiments of the presently disclosed LIDAR scanning modules are therefore more suitable for small to medium sized unmanned aerial vehicle applications than the traditional LIDAR scanners.
Furthermore, because the diode structure 300 typically has different dimensions in two mutually perpendicular directions (e.g., x and y directions, as shown in
To reduce the angles of divergence discussed above, a convex lens can be used to collimate the laser beam. Specifically, a laser diode placed at the rear focal point of a convex lens can collimate the resulting laser beam that is emitted from the laser diode, e.g., produce a beam with parallel rays. However, a convex lens typically has a central symmetry, and due to the existence of astigmatism, the laser beam would not be collimated both on the x-z plane and the y-z plane by the convex lens at the same time. A cylindrical lens can be placed behind the convex lens to adjust the astigmatism, because of the cylindrical lens can have different curvatures in the two axial directions (e.g., a finite curvature in one axis, and an infinite curvature in the other axis).
Embodiments of the present disclosure can increase the difference in the degree of collimation of the laser beam, and stretch the light spot size in a desired direction but not in others. Accordingly, some embodiments include an optical structure that further adds a cylindrical lens (e.g., the optical lens 500, shown as a plano concave cylindrical lens) behind the aforementioned convex lens. Further implementation details are described below.
In the structure 600 shown in
Due to the existence of astigmatism, however, the virtual image point (i.e., Vp1) in the x-z plane of
Further, the plano concave cylindrical lens 602 in the optical structure 600, in one or more embodiments, is placed behind the plano convex lens 604 at a suitable distance L, for example, L=120 mm. In some embodiments, the aperture diameter of the plano concave lens 602 is ϕ2=35 mm. The curvature of the concave cylindrical side that is parallel to the x-z plane (as shown in
Referring back to
With simultaneous reference to
As described above, in accordance with embodiments of the present technology, the optical structures can change the size of a laser beam in a single dimension such that it can illuminate obstacles over a wider range of altitudes than without the optical structure. With the techniques introduced here, the need for a multi-line laser emitter (e.g., emitters 254a-254d shown in
Referring to
An embodiment of the LIDAR system 950 shown in
The scanner can be utilized to perform a terrestrial survey, obstruction detection, or a combination thereof. In some embodiments, the controller on the UAV can be programed to maneuver the vehicle in response to terrain or an obstacle detected by the scanner. This can greatly improve flight safety as well the user's experience (e.g., by reducing the difficulty of controlling the flight) of the UAV system.
Depending on the embodiment, some of the optical structures disclosed herein can create a distribution of light intensity across the laser beam height (e.g., as shown in
Embodiments of the present disclosure also include methods of manufacturing unmanned aerial vehicles. A representative method includes installing a scanning element on an airframe. The scanning element includes a light emitting module positioned to emit light, a light sensing module positioned to detect a reflected portion of the emitted light, and an optical structure coupled to the light emitting module and positioned to increase a beam height of the emitted light while generally maintaining a beam width of the emitted light. The step of installing the scanning element can include coupling a motion mechanism between the airframe and the scanning element. In certain embodiments, the motion mechanism is operable to rotate the scanning element relative to the airframe about a spin axis.
In some embodiments, the method can further include placing a number of light sensors in the light sensing module, and placing a number of light emitters in the light emitting module. The number of light sensors in the light sensing module can be greater than the number of light emitters in the light emitting module. The method can further include placing a plano concave cylindrical lens in the optical structure. Some embodiments of the method further include placing a plano convex lens in the optical structure. The plano convex lens can be situated between the plano concave cylindrical lens and the light emitting module. Both a flat side of the plano convex lens and a flat side of the plano concave cylindrical lens can be facing toward the light emitting module. The plano convex lens, the plano concave cylindrical lens, and the light emitting module can be positioned to cause a virtual image point of the light emitting module, formed from the plano convex lens, to fall within a distance corresponding to a rear focal distance of the plano concave cylindrical lens.
In a number of embodiments, a heightwise beam angle of the emitted light is increased by the optical structure by at least 30 times. In some implementations, a heightwise field of view of an individual light sensor included in the light sensing module is about 10 degrees. In other examples, the heightwise fields of view of multiple light sensors included in the light sensing module are arranged so as not to overlap each other.
The method can further include coupling the scanning element to an actuator operable to spin the scanning element continuously at a generally constant rate. the scanning element can include a scanning platform that carries a scanner. The scanning element can be a light detection and ranging (LIDAR) system.
Methods accordance with various embodiments, can include installing a controller carrying instructions that maneuver the vehicle in response to an input corresponding to terrain or an obstacle detected by the scanning element. In various implementations, the method includes installing a plurality of thrusters on the airframe, the plurality of thrusters positioned to maneuver the vehicle in response to inputs from the controller. In some embodiments, the controller is further configured to estimate a first distance between the vehicle and a detected object based on output from a centermost light sensor among the array of light sensors, and adjust a sensitivity of one or more light sensors based on the estimated first distance. The adjustment can include, for example, increasing a sensitivity for a light sensor located closer to an edge of an array of light sensors. The method can further include performing weight balancing of the scanning element, relative to the spin axis. In addition, the method can include installing a radio frequency module to receive scanning commands from a remote controlling device.
From the foregoing, it will be appreciated that specific embodiments of the technology have been described herein for purposes of illustration, but that various modifications can be made without deviating from the technology. In representative embodiments, the LIDAR devices can have configurations other than those specifically shown and described herein, including other semiconductor constructions. The optical devices described herein may have other configurations in other embodiments, which also produce the desired beam shapes and characteristics described herein.
Certain aspects of the technology described in the context of particular embodiments may be combined or eliminated in other embodiments. For example, aspects of the optical structure described in the context of
To the extent any materials incorporated herein conflict with the present disclosure, the present disclosure controls.
At least a portion of the disclosure of this patent document contains material which is subject to copyright protection. The copyright owner has no objection to the facsimile reproduction by anyone of the patent document or the patent disclosure, as it appears in the Patent and Trademark Office patent file or records, but otherwise reserves all copyright rights whatsoever.
| Number | Date | Country | |
|---|---|---|---|
| Parent | PCT/CN2016/096970 | Aug 2016 | US |
| Child | 16285079 | US |
