Patent Application
20220282460
The present disclosure relates generally to self-propelled work vehicles such as construction and forestry machines, and more particularly to systems and methods for control of certain movements and/or operations of such self-propelled work vehicles based on, e.g., underlying terrain.
Self-propelled work vehicles of this type may for example include excavator machines, forestry machines, front shovel machines, and others. These machines may typically have tracked ground engaging units supporting the undercarriage from the ground surface.
Exemplary work vehicles according to the present disclosure further include attachments comprising work implements that are movable with respect to the work vehicle by various actuators in order to accomplish tasks with the implement. Discussion herein may typically focus on an excavator machine as an exemplary work vehicle, with the corresponding application of moving implements configured as a boom, an arm, a bucket, and the like (collectively a boom assembly), with actuators for moving the implements generally configured as hydraulic cylinders.
When self-propelled work vehicles such as for example excavators travel on slopes, a substantial amount of operator skill may conventionally be required. The operator of an excavator needs to control the associated boom, arm, and bucket positions simultaneously along with the travel direction of the vehicle. For example, if the excavator is travelling uphill the various elements may be positioned to support the excavator body in the climbing steps by executing a ‘pull-up’ action, with attachments initially extended outward and low to the ground. If the excavator is travelling downhill the various elements may be positioned to support the excavator body by executing a ‘push-back’ action, with the attachments again initially extended outward and low to the ground. In any given type of terrain including even flat terrain, the various elements of the work vehicle, particularly working attachments such as the boom, arm, bucket, etc., may be positioned in accordance with the type of terrain to stabilize the work vehicle orientation as a whole and substantially prevent roll-over conditions.
It would be desirable to reliably automate certain coordinated operations based on the type of terrain upon or across which the work vehicle is travelling, including for example ramps and flat surfaces, thereby increasing vehicle stability and further reducing operator fatigue and/or mitigating the impact of operator inexperience when otherwise manually operating a large number of simultaneous controls.
The current disclosure in various embodiments provides an enhancement to conventional systems, at least in part by introducing a novel system and method for monitoring work vehicle orientation, including the positioning of various attachments relative to the work vehicle frame based at least in part on kinematic feedback, and accordingly implementing automation of certain vehicle operations and associated functions during for example uphill and downhill travel of varying degree and/or distance, and travel across relatively flat terrain.
Relating for example to an excavator as the work vehicle, a system and method as disclosed may be configured to automatically control implements such as the arm, bucket, and boom attachments using kinematic feedback further in view of a selected and/or determined travel mode. In the context of a steep uphill grade, the operator may initially place the bucket teeth in a specified manner on the ground surface, and then provide a travel command to a work vehicle controller or equivalent device, whereupon the arm may be automatically retracted as per the rate of travel command. In other exemplary travel modes the boom, arm, and bucket may be positioned automatically in other predetermined positions and/or moved in accordance with predetermined sequences of operation.
In one embodiment, a computer-implemented method as disclosed herein is provided for stability control for a self-propelled work vehicle comprising a plurality of ground engaging units and at least one work implement configured for controllably working terrain. The exemplary disclosed method includes retrieving from data storage at least respective predetermined target positions and/or operations of the at least one work implement, corresponding to a determined travel mode for the self-propelled work vehicle, receiving feedback signals from one or more sensors corresponding to respective current positions and/or operations of the at least one implement, and generating one or more control signals for automatically controlling the at least one work implement to the respective predetermined target positions and/or through the respective operations, responsive to the determined travel mode and the received feedback signals.
In one exemplary aspect of the above-referenced embodiment, the travel mode may be determined in accordance with manual user selection from among a plurality of travel modes via a user interface.
In another exemplary aspect of the above-referenced embodiment, the method may further include receiving feedback signals corresponding to a predicted work vehicle grade from one or more sensors linked to a grade control unit, wherein the determined travel mode is confirmed via the predicted work vehicle grade.
In another exemplary aspect of the above-referenced embodiment, the method may further include receiving feedback signals corresponding to a predicted work vehicle grade from one or more sensors linked to a grade control unit, wherein the travel mode is determined in accordance with the predicted work vehicle grade.
In another exemplary aspect of the above-referenced embodiment, the method may further include receiving feedback signals corresponding to travel direction and/or speed commands for the self-propelled work vehicle during the determined travel mode.
The one or more control signals in accordance with at least the preceding aspect may optionally be generated for controlling the at least one work implement to the respective predetermined target positions and/or through the respective operations, responsive to the determined travel mode, the received feedback signals corresponding to respective current positions and/or operations of the at least one implement, and the received feedback signals corresponding to the travel commands.
The one or more control signals in accordance with at least the preceding aspect may optionally be generated for controlling the work vehicle speed during the determined travel mode, responsive to at least the predetermined target positions and/or operations of the at least one work implement and the received feedback signals corresponding to respective current positions and/or operations of the at least one implement.
For example, the work vehicle may be directed to stop during at least one required operation of the at least one implement during a determined travel mode, and to move forward only while the at least one implement is maintained in a predetermined position during the determined travel mode.
In another exemplary aspect of the above-referenced embodiment, the method may further include enabling manual dismissal of the automatic control during the determined travel mode via a user interface.
In another exemplary aspect of the above-referenced embodiment, the determined travel mode may correspond to a direction and/or amount of slope for terrain upon which the work vehicle travels.
In another embodiment, an inventive self-propelled work vehicle as disclosed herein may include a plurality of ground engaging units supporting a vehicle chassis, at least one work implement supported by the vehicle chassis and configured for controllably working terrain, one or more sensors configured to provide feedback signals corresponding to respective current positions and/or operations of the at least one implement, and data storage having stored therein at least respective predetermined target positions and/or operations of the at least one work implement corresponding to each of a plurality of travel modes for the self-propelled work vehicle. A controller associated with the work vehicle is further configured to direct the performance of operations corresponding to steps of the above-referenced method embodiment and optionally one or more of the above-referenced exemplary aspects thereof.
Numerous objects, features and advantages of the embodiments set forth herein will be readily apparent to those skilled in the art upon reading of the following disclosure when taken in conjunction with the accompanying drawings.
Referring now to
A main frame 32 is supported from the undercarriage 22 by a swing bearing 34 such that the main frame 32 is pivotable about a pivot axis 36 relative to the undercarriage 22. The pivot axis 36 is substantially vertical when a ground surface 38 engaged by the ground engaging units 24 is substantially horizontal. A swing motor (not shown) is configured to pivot the main frame 32 on the swing bearing 34 about the pivot axis 36 relative to the undercarriage 22.
A work implement 42 in the context of the referenced work vehicle 20 includes a boom assembly 42 with a boom 44, an arm 46 pivotally connected to the boom 44, and a working tool 48. The term “implement” may be used herein to describe the boom assembly (or equivalent thereof) collectively, or individual elements of the boom assembly or equivalent thereof. The boom 44 is pivotally attached to the main frame 32 to pivot about a generally horizontal axis relative to the main frame 32. The working tool in this embodiment is an excavator shovel (or bucket) 48 which is pivotally connected to the arm 46. The boom assembly 42 extends from the main frame 32 along a working direction of the boom assembly 42. The working direction can also be described as a working direction of the boom 44. As described herein, control of the work implement 42 may relate to control of any one or more of the associated components (e.g., boom 44, arm 46, tool 48).
In the embodiment of
An operator's cab 60 may be located on the main frame 32. The operator's cab 60 and the boom assembly 42 may both be mounted on the main frame 32 so that the operator's cab 60 faces in the working direction 58 of the boom assembly. A control station 62 may be located in the operator's cab 60.
Also mounted on the main frame 32 is an engine 64 for powering the work vehicle 20. The engine 64 may be a diesel internal combustion engine. The engine 64 may drive a hydraulic pump to provide hydraulic power to the various operating systems of the work vehicle 20.
As schematically illustrated in
The controller 112 is configured to receive input signals from some or all of various sensors collectively defining a sensor system 104, individual examples of which may be described below. Various sensors in the sensor system 104 may typically be discrete in nature, but signals representative of more than one input parameter may be provided from the same sensor, and the sensor system 104 may further refer to signals provided from the machine control system.
The controller 112 may be configured to produce outputs, as further described below, to the user interface 114 for display to the human operator. For example, the controller 112 may be configured to communicate preferred positions of the work vehicle 20 and associated implements 42, 44, 46, 48 based on determined travel mode, slope of the terrain, and/or travelling direction. In the context of an excavator as the work vehicle 20, the preferred positions may relate to at least a position of the bucket 48 relative to the main frame, the ground surface, the travelling direction, or the like, in view of the various embodiments as further disclosed herein.
The controller 112 may further or in the alternative be configured to generate control signals for controlling the operation of respective actuators, or signals for indirect control via intermediate control units, associated with a machine steering control system 126, a machine implement control system 128, and an engine speed control system 130. The control systems 126, 128, 130 may be independent or otherwise integrated together or as part of a machine control unit in various manners as known in the art. The controller 112 may for example generate control signals for controlling the operation of various actuators, such as hydraulic motors or hydraulic piston-cylinder units (not shown), and electronic control signals from the controller 112 may actually be received by electro-hydraulic control valves associated with the actuators such that the electro-hydraulic control valves will control the flow of hydraulic fluid to and from the respective hydraulic actuators to control the actuation thereof in response to the control signal from the controller 112.
The controller 112 includes or may be associated with a processor 150, a computer readable medium 152, a communication unit 154, data storage 156 such as for example a database network, and the aforementioned user interface 114 or control panel 114 having a display 118. An input/output device 116, such as a keyboard, joystick or other user interface tool 116, is provided so that the human operator may input instructions to the controller. It is understood that the controller 112 described herein may be a single controller having some or all of the described functionality, or it may include multiple controllers wherein some or all of the described functionality is distributed among the multiple controllers.
Various operations, steps or algorithms as described in connection with the controller 112 can be embodied directly in hardware, in a computer program product such as a software module executed by the processor 150, or in a combination of the two. The computer program product can reside in RAM memory, flash memory, ROM memory, EPROM memory, EEPROM memory, registers, hard disk, a removable disk, or any other form of computer-readable medium 152 known in the art. An exemplary computer-readable medium 152 can be coupled to the processor 150 such that the processor 150 can read information from, and write information to, the memory/storage medium 152. In the alternative, the medium 152 can be integral to the processor 150. The processor 150 and the medium 152 can reside in an application specific integrated circuit (ASIC). The ASIC can reside in a user terminal. In the alternative, the processor 150 and the medium 152 can reside as discrete components in a user terminal.
The term “processor” 150 as used herein may refer to at least general-purpose or specific-purpose processing devices and/or logic as may be understood by one of skill in the art, including but not limited to a microprocessor, a microcontroller, a state machine, and the like. A processor 150 can also be implemented as a combination of computing devices, e.g., a combination of a DSP and a microprocessor, a plurality of microprocessors, one or more microprocessors in conjunction with a DSP core, or any other such configuration.
The communication unit 154 may support or provide communications between the controller 112 and external systems or devices, and/or support or provide communication interface with respect to internal components of the self-propelled work vehicle 20. The communications unit may include wireless communication system components (e.g., via cellular modem, WiFi, Bluetooth or the like) and/or may include one or more wired communications terminals such as universal serial bus ports.
The data storage 156 as further described below may, unless otherwise stated, generally encompass hardware such as volatile or non-volatile storage devices, drives, electronic memory, and optical or other storage media, as well as in certain embodiments one or more databases residing thereon.
Referring next to
The method 300 may include receiving one or more inputs corresponding to a determined travel mode for the work vehicle 20 (step 310). Certain inputs may take the form of operator commands, via for example the user interface 114, regarding a configuration of terrain to be traversed, and in some embodiments may encompass manually/directly provided parameters and/or operations, sequences of parameters and/or operations, etc., as associated with the travel mode.
Exemplary such inputs may include travel command output signals corresponding to manual engagement of interface tools such as for example a pedal or joystick in the operator's cab 60.
Further exemplary such inputs may include direct selection of a travel mode to be implemented via a user interface tool 116 such as a sealed switch module (SSM), push button, touch screen, or equivalent device. In an embodiment, a plurality of predetermined travel modes may be graphically presented or otherwise individually selectable by the operator or equivalent user. The user interface 114 for travel mode selection may be provided in the operator's cab 60 or in certain embodiments may be remotely positioned relative to the work vehicle 20, for example a graphical interface generated on a mobile computing device or the like.
Still further exemplary such inputs may include output signals corresponding to an upcoming slope as detected via a 3D grade control system associated with the work vehicle 20. Such grade control systems may be configured to detect or otherwise predict changes in the slope of a terrain to be traversed by the work vehicle 20, using corresponding sensors such as imaging sensors, ultrasonic sensors, optical sensors, or the like, wherein the slope inputs may be obtained or otherwise selectively provided for algorithms as disclosed herein.
One or more implement sensor inputs (step 312) may be received as feedback signals from respective sources in the sensor system 104, such as for example from a kinematic detection system configured to monitor the current positions and/or operations of the element(s) (e.g., boom 44, arm 46, and/or bucket 48) in respective coordinate space, such as for example in an independent coordinate frame respective to a global navigation frame of the work vehicle 20. An exemplary kinematic system may include inertial measurement units (IMUs) mounted or affixed to elements of the boom assembly and/or main frame 32 of the work vehicle 20, and which further include a number of sensors including, but not limited to: accelerometers, which measure (among other things) velocity and acceleration; gyroscopes, which measure (among other things) angular velocity and angular acceleration; and/or magnetometers, which measure (among other things) strength and direction of a magnetic field.
The sensor system 104 may in certain embodiments optionally include sensors for implementing a counter-weight balance feature to improve traction on steep grades, for example by measuring or determining load and/or traction of the ground engaging units 24 of the work vehicle 20 relative to the ground surface 38. Non-limiting examples may include load sensor, pressure sensor, and/or true ground speed sensor measurements for determining track slip, each being generally known to those of skill in the art.
In other embodiments, again without limitation of the scope of any disclosed invention herein unless otherwise specifically stated, the sensor system 104 may include one or more global positioning system (GPS) sensing units or an equivalent, integral with or otherwise independent of a grade control system and fixed relative to the main frame 32, which can detect an absolute position and orientation of the work vehicle 20 within an external reference system and can further detect changes in such position and orientation, and/or a camera based system which can observe surrounding structural features via image processing, and can respond to the orientation of the work vehicle 20 relative to those surrounding structural features.
Some or all of the preceding elements of a sensor system 104 may accordingly enable additional features that may be contemplated within the scope of a system as disclosed herein. For example, an operator of a self-propelled work vehicle 20 must sometimes manage a vertical position of an implement such as the bucket 48, or a downward pressure exerted thereby, to keep the tracks 24 engaged with the ground 38 for proper traction. The controller 112 may be configured to estimate down-force on the bucket 48 as a way to avoid excessive lifting of one end of the work vehicle, optionally utilizing sensor inputs as previously noted such as pressure values, track slip estimates (via a ground speed reference like GPS, camera, etc.) or the like. Alternatively, different operator inputs (e.g., boom commands) may be programmatically interpreted as vertical commands, further allowing the operator to adjust a downward force while automating the horizontal motion.
Still another example of features enabled by sensor system 104 inputs and associated controller 112 programming may include a tip-over warning feature, indicating when the work vehicle 20 is approaching an unsafe position or orientation, and in some embodiments indicating recommended mitigation actions, e.g., where to position the bucket 48 under the detected circumstances. In such an example, the work vehicle 20 may be configured to monitor slope and calculate the ideal pose as previously noted, but instead of automatically acting it may put bounds on that pose and slope and generate a warning output to the operator when those bounds are exceeded, and/or indicate to the operator a suggested action.
One or more steering control and/or speed control inputs (step 314) may also be received as feedback regarding travel commands from respective sources in the sensor system 104, and further processed along with the implement sensor inputs and travel mode inputs (step 320). In such embodiments control operations may accordingly be executed responsive to one or more of a determined (e.g., selected) travel mode, feedback signals corresponding to respective current positions and/or operations of the implements (e.g., boom 44, arm 46, and/or bucket 48 individually or collectively as a boom assembly 42), and the aforementioned feedback signals corresponding to travel commands.
Such processing, which may be carried out by the controller 112 as previously referenced, may further include stored target values 316 for each of one or more elements of the work vehicle 20 (e.g., boom assembly, steering, vehicle speed) in accordance with the selected or determined travel mode. The stored target values may be retrievable by the controller 112 from associated data storage 156 in view of a determined travel mode, and further may comprise for example respective predetermined target positions and/or operations of each relevant work implement or element thereof (e.g., relative positions and/or or movements of the excavator boom 44, arm 46, bucket 48, etc.).
Control signals may then be generated (step 320) regarding one or more parameters or operations (or sequences of parameters or operations) for automation in conjunction with the selected or determined travel mode, and may be provided to any one or more of the steering control system 126 (step 330), the implement control system 128 (step 332), and the engine speed control system 130 (step 334) depending on the relevant application. The control signals, and the relevant control systems for which automation is selectively utilized, may be dependent on any or all of various conditions including for example a determined travel mode, a grade/slope of the terrain across which the work vehicle travels, an angle at which the work vehicle travels up or down a sloped terrain, a load carried by the work vehicle, a condition of the ground surface, etc.
Various exemplary travel modes and corresponding implement positions, operations, and/or sequences of operations may be further described by reference to
In a first travel mode as represented in
For extended or repeated periods of uphill operation, it may be contemplated that the operator will need to stop the work vehicle 20 and extend the boom assembly 42 to re-position the teeth of the bucket 48 in the ground surface 38 several times, i.e., every time the excavator 20 approaches the bucket 48 as it travels uphill.
It may further be contemplated and accordingly programmed in the controller 112 that the work vehicle 20 is directed to stop during at least one required operation of the boom 44, arm 46, and/or bucket 48 during a determined travel mode, and to move forward only while the respective implement 42, 44, 46, 48 is maintained in a predetermined position during the determined travel mode.
In a second travel mode as represented in
For extended or repeated periods of downhill operation, it may be contemplated that once the excavator is properly positioned on the slope, it may utilize the drag generated by the parallel bucket position for stable movement throughout the duration.
In a third travel mode as represented in
In a fourth travel mode as represented in
In a fifth travel mode as represented in
In some embodiments, the positions or operations for a given implement or collection of implements 42, 44, 46, 48 may be determined not only in view of a travel mode but further taking into account other conditions such as for example a work state and/or load. For example, inputs from a payload weighing system associated with the work vehicle 20 may influence how the various implement elements can be safely positioned for a given slope or degree thereof. In association with a given travel mode, the positions and/or operations of various implements 42, 44, 46, 48 may be further dependent on work vehicle travel commands (forward movement and/or steering) as well as ground surface conditions, wherein a bucket 48 may for example be positioned and thereby utilized to help stabilize the main frame 32 of the work vehicle 20 during turning movements of the ground engaging units 24 on a sloped ground surface 38, etc.
The user interface 114 as disclosed herein may be configured for enabling or overriding the automated control functions via any manual hydraulic command, such as via a button or equivalent on/off actuator. Alternatively, such an override may be implemented by the operator simply carrying out the functions manually according to the conventional techniques, such as for example manual boom 44, arm 46, or bucket 48 commands using the relevant joysticks. In various embodiments, manual interaction by the operator may not disable or interrupt the automated controls for a determined travel mode, but rather take the form of travel commands as further (e.g., additive) inputs to the controller for augmenting and/or modifying the associated control signals. The operator may accordingly adjust the motion of the work vehicle 20 without explicitly interrupting an overall automated coordination with the ground engaging units 24.
In a particular embodiment, the user interface 114 may include tools corresponding to a selective disable (automation off) feature, a selective enable (automation on) feature, and an indication feature wherein the controller 112 provides signals to indicate and/or recommend positions and/or operations of the work vehicle 20 and associated implements 42, 44, 46, 48 based on the travel mode. For example, it may be desirable to restrict automation features to steep slopes or other treacherous conditions of the ground surface, whereas only visual and/or audible indications may be sufficient for travel modes associated with flat ground surfaces or ground surfaces having a moderate slope and otherwise normal operating conditions.
As used herein, the phrase “one or more of,” when used with a list of items, means that different combinations of one or more of the items may be used and only one of each item in the list may be needed. For example, “one or more of” item A, item B, and item C may include, for example, without limitation, item A or item A and item B. This example also may include item A, item B, and item C, or item B and item C.
Thus, it is seen that the apparatus and methods of the present disclosure readily achieve the ends and advantages mentioned as well as those inherent therein. While certain preferred embodiments of the disclosure have been illustrated and described for present purposes, numerous changes in the arrangement and construction of parts and steps may be made by those skilled in the art, which changes are encompassed within the scope and spirit of the present disclosure as defined by the appended claims. Each disclosed feature or embodiment may be combined with any of the other disclosed features or embodiments.
