Grounds working vehicle employing performance enhancement functions

Abstract

A grounds working vehicle comprises a propulsion system, a positioning sensor, a navigation system operably coupled to the positioning sensor and the propulsion system, and a collision avoidance system. A controller is operably coupled to the propulsion system, the positioning sensor, the navigation system, and the collision avoidance system. The controller, when the vehicle is operating in an autonomous mode, is configured to limit a speed and a turn rate of the vehicle to specified operating ranges dependent on the collision avoidance system.

Description

GROUNDS WORKING VEHICLE EMPLOYINGPERFORMANCE ENHANCEMENT FUNCTIONS

[0001] The present application claims priority to and / or the benefit of U.S. Provisional Patent Application No. 63 / 540,551, filed September 26, 2023, which is incorporated herein by reference in its entirety.

[0002] The present disclosure relates to grounds working vehicles and, more particularly, to such vehicles operable in a manual mode and an autonomous mode.SUMMARY

[0003] Embodiments of the present disclosure relate to grounds working vehicles that employ performance enhancement functions when operating in a manual mode and an autonomous mode. Representative grounds working vehicles include grounds maintenance machines such as ride-on, stand-on, walk-behind, and tow-behind lawn mowers. The performance enhancement functions of the present disclosure ensure that a grounds working vehicle consistently operates within prescribed guidelines in both a manual mode and an autonomous mode.

[0004] In one aspect, the present disclosure relates to a method of operating a grounds working vehicle comprising enabling an autonomous mode of the vehicle and, while the vehicle is operating in the autonomous mode, limiting a speed and a turn rate of the vehicle to specified operating ranges dependent on a collision avoidance system of the vehicle.

[0005] In another aspect, the present disclosure relates to a grounds working vehicle comprising a propulsion system, a positioning sensor, a navigation system operably coupled to the positioning sensor and the propulsion system, and a collision avoidance system. A controller is operably coupled to the propulsion system, the positioning sensor, the navigation system, and the collision avoidance system. The controller, when the vehicle is operating in an autonomous mode, is configured to limit a speed and a turn rate of the vehicle to specified operating ranges dependent on the collision avoidance system.

[0006] In a further aspect, the present disclosure relates to a method of operating a grounds working vehicle comprising enabling a manual mode of the vehicle. While operating the vehicle in the manual mode, the method comprises determining whether a position of a speed control lever of the vehicle corresponds to a wheel motor speed that falls within a speed tolerance, and inhibiting movement of the vehicle in response to the wheel motor speed falling outside of the speed tolerance.

[0007] In another aspect, the present disclosure relates to a grounds working vehicle comprising a housing coupled to a working implement and a set of wheels including drive wheels supporting the housing and the working implement over a ground surface. A propulsion system is operably coupled to the drive wheels. The vehicle comprises a positioning sensor, a navigation system operably coupled to the positioning sensor and the propulsion system, a collision avoidance system, and a mode switch that facilitates selection between an autonomous mode and a manual mode. A controller is operably coupled to the propulsion system, the positioning sensor, the navigation system, the collision avoidance system, and the mode switch. The controller, when the vehicle is operating in the manual mode, is configured to determine whether a position of the speed control lever corresponds to a wheel motor speed that falls within a speed tolerance, and to inhibit movement of the vehicle in response to the wheel motor speed falling outside of the speed tolerance.

[0008] The summary is not intended to describe each embodiment or every implementation of the present disclosure. A more complete understanding will become apparent and appreciated by reference to the following detailed description and claims taken in view of the accompanying figures of the drawing.BRIEF DESCRIPTION OF THE DRAWINGS

[0009] Illustrative embodiments will be further described with reference to the figures of the drawing, wherein:

[0010] FIG. l is a perspective view of a grounds working vehicle in the form of a walk- behind / tow-behind lawn mower according to embodiments described herein.

[0011] FIG. 2A is a first portion of a block diagram showing a control system of a grounds working vehicle selectively operative in a manual mode and an autonomous mode according to embodiments described herein.

[0012] FIG. 2B is a second portion of a block diagram showing a control system of a grounds working vehicle selectively operative in a manual mode and an autonomous mode according to embodiments described herein.

[0013] FIG. 3 is a block diagram on a control system of a grounds working vehicle configured to implement a number of performance enhancement functions according to embodiments described herein.

[0014] FIG. 4 illustrates a method of controlling a grounds working vehicle configured to implement performance enhancement functions according to embodiments described herein.

[0015] FIG. 5 illustrates a grounds working vehicle configured with sensors for implementing performance enhancement functions according to embodiments described herein.

[0016] FIG. 6 illustrates a method of controlling a grounds working vehicle configured to implement performance enhancement functions according to embodiments described herein.

[0017] FIG. 7 illustrates a method of controlling a grounds working vehicle configured to implement performance enhancement functions according to embodiments described herein.

[0018] FIG. 8 illustrates a method of controlling a grounds working vehicle configured to implement performance enhancement functions according to embodiments described herein.

[0019] The figures are rendered primarily for clarity and, as a result, are not necessarily drawn to scale. Moreover, various structures / components may be shown diagrammatically or removed from some or all of the views to better illustrate aspects of the depicted embodiments, or where inclusion of such structures / components is not necessary to an understanding of the various illustrative embodiments described herein. The lack of illustration / description of such structure / components in a particular figure is, however, not to be interpreted as limiting the scope of the various embodiments in any way.DETAILED DESCRIPTION

[0020] In the following detailed description of illustrative embodiments, reference is made to the accompanying figures of the drawing which form a part hereof. It is to be understood that other embodiments, which may not be described and / or illustrated herein, are certainly contemplated.

[0021] All headings provided herein are for the convenience of the reader and should not be used to limit the meaning of any text that follows the heading, unless so specified.Moreover, unless otherwise indicated, all numbers expressing quantities, and all terms expressing direction / orientation (e.g., vertical, horizontal, parallel, perpendicular, etc.) in the specification and claims are to be understood as being modified in all instances by the term “about.” The term “and / or” (if used) means one or all of the listed elements or a combination of any two or more of the listed elements. The term “i.e.” is used as an abbreviation for the Latin phrase id est and means “that is.” The term “e.g.,” is used as an abbreviation for the Latin phrase exempli gratia and means “for example.”

[0022] It is noted that the terms “have,” “include,” “comprises,” and variations thereof, do not have a limiting meaning, and are used in their open-ended sense to generally mean “including, but not limited to,” where the terms appear in the accompanying description and claims. Further, “a,” “an,” “the,” “at least one,” and “one or more” are used interchangeably herein. Moreover, relative terms such as “left,” “right,” “front,” “fore,” “forward,” “rear,” “aft,” “rearward,” “top,” “bottom,” “side,” “upper,” “lower,” “above,” “below,” “horizontal,” “vertical,” and the like may be used herein and, if so, are from the perspective shown in the particular figure, or while the grounds working vehicle is in an operating configuration. These terms are used only to simplify the description, however, and not to limit the interpretation of any embodiment described.

[0023] While the construction of the actual grounds working vehicle is not necessarily central to an understanding of embodiments of this disclosure, FIG. 1 illustrates one example of a grounds working vehicle 100 in the form of a mower (referred to as mower 100). FIGS. 2A, 2B, and 3 are block diagrams showing various components of the mower 100 shown in FIG. 1. It is noted that the components shown in FIGS. 2A, 2B, and 3 can be incorporated in a grounds working vehicle that differs in construction and functionality from the representative mower 100 shown in FIG. 1.

[0024] FIG. 1 shows a perspective view of the mower 100 and FIGS. 2 A, 2B, and 3 show various components of the mower 100 illustrated in block diagram form. The mower 100 may include a frame 102 that carries and / or encloses various components of the mower 100 as described below. The mower 100 further includes ground support members, such as wheels, rollers, or tracks. In the illustrated embodiment, ground support members shown include drive wheels 104 and front wheels 106 (e.g., caster wheels) that together support the frame 102 upon a ground (grass) surface. The drive wheels 104 and front wheels 106 also support an implement 110 (e.g., a cutting deck) upon the ground surface.

[0025] The mower 100 shown in FIG. 1 is referred to as a walk-behind mower, such that an operator can walk behind and control the mower 100 during mower operation. The mower 100 can include an optional rider platform 120 which allows the operator to ride behind the mower 100 and control the mower 100 during mower operation. The rider platform 120 is commonly referred to as a sulky. With the sulky 120 deployed as shown in FIG. 1, the mower 100 can be referred to as a tow-behind mower. The sulky 120 shown in FIG. 1 includes a single wheel that supports left and right foot platforms. In some implementations, the sulky 120 can include two wheels coupled to a common axle.

[0026] The mower 100 includes a propulsion system that causes the drive wheels 104 to rotate in a direction and rate dictated by command signals received from operator controls 209. The operator controls 209 include a left-hand (LH) control lever 225 and a right-hand (RH) control lever 229. The LH control lever 225 controls the speed of the left drive wheel in forward or reverse directions, and the RH control lever 229 controls the speed of the right drive wheel in forward or reverse directions. The LH control lever 225 supports a left-hand operator presence control (OPC) 224 and the RH control lever 229 supports a right-hand OPC 228. The LH OPC 224 and RH OPC 228 must be activated by the operator in order for command signals received from the LH and RH control levers 225, 229 to be acted on by a controller 203 of the mower 100 (see FIG. 2 A).

[0027] The propulsion system of the mower 100 can cause the drive wheels 104 to rotate in a direction and rate dictated by command signals received from the LH and RH control levers 225, 229. In some embodiments, the propulsion system includes an internal combustion engine 108 that powers a generator which is coupled to an electric traction drive comprising left and right electric wheel motors operatively coupled to the left and right drive wheels 104 (see FIG. 2B).

[0028] The mower 100 can be referred to as a zero-turn-radius (ZTR) mower. That is to say, the propulsion system may include a separate wheel motor for each of the left and right drive wheels 104 so that speed and direction of each drive wheel may be independently controlled. As such, the mower 100 can implement a zero-tum-radius pivot (e.g., a ZTR turn or spin), where one drive wheel rotates backwards and the other drive wheel rotates forward at the same speed, such that a midpoint between the two drive wheels 104 rotates above a fixed ground location.

[0029] An implement 110 (e.g., a cutting apparatus) may be connected to the frame 102 or a lift arm (generally longitudinally in front of, mid-mounted between the drive wheels 104).The implement 110 may be a cutting deck which includes one or more cutting blades. During operation, the cutting blades rotate at a speed sufficient to sever grass and other vegetation as the implement 110 passes over the ground surface. While illustrated as a cutting deck, the implement 110 may be any tool (e.g., aerator, spreader, sprayer etc.) that attaches to the frame 102.

[0030] Embodiments of the disclosure are defined in the claims. However, below there is provided a non-exhaustive listing of non-limiting examples. Any one or more of the features of these examples may be combined with any one or more features of another example, embodiment, or aspect described herein.

[0031] Example Exl . A method of operating a grounds working vehicle comprises enabling an autonomous mode of the vehicle and, while the vehicle is operating in the autonomous mode, limiting a speed and a turn rate of the vehicle to specified operating ranges dependent on a collision avoidance system of the vehicle.

[0032] Example Ex2. The method according to Exl, wherein limiting the turn rate of the vehicle comprises limiting a rate of a zero-tum-radius turn of the vehicle to a maximum turn rate.

[0033] Example Ex3. The method according to Exl or Ex2, comprising preventing travel of the vehicle in reverse but permitting the zero-tum-radius turn of the vehicle.

[0034] Example Ex4. The method according to any one of Exl-Ex3, wherein the turn rate of the vehicle is dependent on a difference in speed of left and right drive wheels of the vehicle.

[0035] Example Ex5. The method according to any one of Exl-Ex4, comprising preventing forward and reverse drive wheel speeds of the vehicle from exceeding maximum forward and reverse speeds, respectively.

[0036] Example Ex6. The method according to any one of Exl-Ex5, wherein the autonomous mode is enabled in response to selection of the autonomous mode and receiving an autonomous mode activation signal.

[0037] Example Ex7. The method according to any one of Exl-Ex6, wherein limiting the speed and the turn rate of the vehicle to the specified operating ranges allows the collision avoidance system to avoid a collision between the vehicle and an object in a path of the vehicle.

[0038] Example Ex8. The method according to any one of Exl-Ex7, wherein the vehicle is operable in the autonomous mode and a manual mode, and the method comprises inhibiting movement of the vehicle in response to detecting a mode change during movement of the vehicle.

[0039] Example Ex9. The method according to any one of Exl-Ex8, comprising inhibiting movement of the vehicle in response to detecting an obstacle in a path of the vehicle by collision avoidance system.

[0040] Example ExlO. The method according to any one of Exl-Ex9, comprising inhibiting movement of the vehicle in response to detecting a tilt of the vehicle in excess of a tilt threshold.

[0041] Example Exl 1. The method according to any one of Exl-ExlO, comprising disabling the autonomous mode of the vehicle in response to detecting deployment of a towable operator platform of the vehicle.

[0042] Example Exl2. The method according to any one of Exl-Exl 1, comprising moving the vehicle within a work region defined by one or more boundaries that are taught to the vehicle in a training mode initiated by an operator of the vehicle.

[0043] Example Exl3. The method according to any one of Exl-Exl2, comprising activating a cutting apparatus of the vehicle in response to a cutting apparatus activation signal.

[0044] Example Exl4. The method according to Exl3, comprising detecting a faulty component of the cutting apparatus and deactivating the cutting apparatus in response to detecting the faulty component.

[0045] Example Exl5. A grounds working vehicle comprises a propulsion system, a positioning sensor, a navigation system operably coupled to the positioning sensor and the propulsion system, and a collision avoidance system. A controller is operably coupled to the propulsion system, the positioning sensor, the navigation system, and the collision avoidance system. The controller, when the vehicle is operating in an autonomous mode, is configured to limit a speed and a turn rate of the vehicle to specified operating ranges dependent on the collision avoidance system.

[0046] Example Exl6. The vehicle according to Exl5, wherein the controller, in the autonomous mode, is configured to limit a rate of a zero-turn-radius turn of the vehicle to a maximum turn rate dependent on the speed of the vehicle.

[0047] Example Exl7. The vehicle according to Exl5 or Exl6, wherein the controller, in the autonomous mode, is configured to prevent travel of the vehicle in reverse but permit a zero-tum-radius turn of the vehicle.

[0048] Example Exl8. The vehicle according to any one of Exl5-Exl7, wherein the turn rate of the vehicle is dependent on a difference in speed of left and right drive wheels of the vehicle.

[0049] Example Exl9. The vehicle according to any one of Exl5-Exl8, wherein the controller, in the autonomous mode, is configured to prevent forward and reverse drive wheel speeds of the vehicle from exceeding maximum forward and reverse speeds, respectively.

[0050] Example Ex20. The vehicle according to any one of Exl5-Exl9, wherein the controller is configured to enable the autonomous mode in response to receiving an autonomous mode activation signal from a mode switch.

[0051] Example Ex21. The vehicle according to any one of Exl5-Ex20, wherein the controller, in the autonomous mode, is configured to limit the speed and the turn rate of the vehicle to the specified operating ranges to allow the collision avoidance system to avoid a collision between the vehicle and an object in a path of the vehicle.

[0052] Example Ex22. The vehicle according to any one of Exl5-Ex21, wherein the controller is configured to inhibit movement of the vehicle in response to detecting a mode change during movement of the vehicle.

[0053] Example Ex23. The vehicle according to any one of Exl5-Ex22, wherein the controller, in the autonomous mode, is configured to inhibit movement of the vehicle in response to detection of an obstacle in a path of the vehicle by the collision avoidance system.

[0054] Example Ex24. The vehicle according to any one of Exl5-Ex23, comprising a tilt sensor operably coupled to the controller, wherein the controller, in the autonomous mode, is configured to inhibit movement of the vehicle in response to detecting a tilt of the vehicle in excess of a tilt threshold.

[0055] Example Ex25. The vehicle according to any one of Exl5-Ex24, comprising a towable operator platform, wherein the controller is configured to disable the autonomous mode in response to detecting deployment of the towable operator platform.

[0056] Example Ex26. The vehicle according to any one of Exl5-Ex25, wherein the controller, in the autonomous mode, is configured to move the vehicle within a work regiondefined by one or more boundaries that are taught to the vehicle in a training mode initiated by an operator of the vehicle.

[0057] Example Ex27. The vehicle according to any one of Exl5-Ex26, wherein the working implement comprises a cutting apparatus and the controller, in the autonomous mode, is configured to activate the cutting apparatus in response to a cutting apparatus activation signal.

[0058] Example Ex28. The vehicle according to Ex27, wherein the controller is configured to detect a faulty component of the cutting apparatus and deactivate the cutting apparatus in response to detecting the faulty component.

[0059] Example Ex29. A method of operating a grounds working vehicle comprises enabling a manual mode of the vehicle and, while operating the vehicle in the manual mode, determining whether a position of a speed control lever of the vehicle corresponds to a wheel motor speed that falls within a speed tolerance, and inhibiting movement of the vehicle in response to the wheel motor speed falling outside of the speed tolerance.

[0060] Example Ex30. The method according to Ex29, comprising preventing forward and reverse drive wheel speeds of the vehicle from exceeding maximum forward and reverse speeds, respectively.

[0061] Example Ex31. The method according to Ex29 or Ex30, wherein the manual mode is enabled in response to activation of an operator presence control of the vehicle.

[0062] Example Ex32. The method according to any one of Ex29-Ex31, wherein the vehicle is operable in the manual mode and an autonomous mode, and the method comprises inhibiting movement of the vehicle in response to detecting a mode change during movement of the vehicle.

[0063] Example Ex33. The method according to any one of Ex29-Ex32, comprising moving the vehicle within a work region defined by one or more boundaries that are taught to the vehicle in a training mode initiated by an operator of the vehicle.

[0064] Example Ex34. The method according to any one of Ex29-Ex33, comprising activating a cutting apparatus of the vehicle in response to a cutting apparatus activation signal.

[0065] Example Ex35. The method according to Ex34, comprising detecting a faulty component of the cutting apparatus and deactivating the cutting apparatus in response to detecting the faulty component.

[0066] Example Ex36. A grounds working vehicle comprises a housing coupled to a working implement, a set of wheels including drive wheels supporting the housing and the working implement over a ground surface, a propulsion system operably coupled to the drive wheels and a speed control lever, a positioning sensor, a navigation system operably coupled to the positioning sensor and the propulsion system, and a collision avoidance system. A controller is operably coupled to the propulsion system, the positioning sensor, the navigation system, and the collision avoidance system. The controller, when the vehicle is operating in a manual mode, is configured to determine whether a position of the speed control lever corresponds to a wheel motor speed that falls within a speed tolerance, and to inhibit movement of the vehicle in response to the wheel motor speed falling outside of the speed tolerance.

[0067] Example Ex37. The vehicle according to Ex36, wherein the controller, in the manual mode, is configured to prevent forward and reverse drive wheel speeds from exceeding maximum forward and reverse speeds, respectively.

[0068] Example Ex38. The vehicle according to Ex36 or Ex37, wherein the controller is configured to enable the manual mode in response to activation of an operator presence control of the vehicle.

[0069] Example Ex39. The vehicle according to any one of Ex36-Ex38, wherein the controller is configured to inhibit movement of the vehicle in response to detecting a mode change during movement of the vehicle.

[0070] Example Ex40. The vehicle according to any one of Ex36-Ex39, wherein the controller is configured to move the vehicle within a work region defined by one or more boundaries that are taught to the vehicle in a training mode initiated by an operator of the vehicle.

[0071] Example Ex41. The vehicle according to any one of Ex36-Ex40, wherein the controller is configured to activate a cutting apparatus of the vehicle in response to a cutting apparatus activation signal.

[0072] Example Ex42. The vehicle according to Ex41, wherein the controller is configured to detect a faulty component of the cutting apparatus and deactivate the cutting apparatus in response to detecting the faulty component.

[0073] Example Ex43. A method of operating a grounds working vehicle comprises enabling an autonomous mode of the vehicle, and, while the vehicle is operating in theautonomous mode, limiting a speed and a turn rate of the vehicle to specified operating ranges dependent on a collision avoidance system of the vehicle. The method also comprises enabling a manual mode of the vehicle, and, while operating the vehicle in the manual mode, determining whether a position of a speed control lever of the vehicle corresponds to a wheel motor speed that falls within a speed tolerance, and inhibiting movement of the vehicle in response to the wheel motor speed falling outside of the speed tolerance.

[0074] Example Ex44. A grounds working vehicle comprising a housing coupled to a working implement, a set of wheels including drive wheels supporting the housing and the working implement over a ground surface, a propulsion system operably coupled to the drive wheels, a positioning sensor, a navigation system operably coupled to the positioning sensor and the propulsion system, a collision avoidance system, and a mode switch that facilitates selection between an autonomous mode and a manual mode. A controller is operably coupled to the propulsion system, the positioning sensor, the navigation system, the obstacle detection system, and the mode switch. The controller, when the vehicle is operating in the autonomous mode, is configured to limit a speed and a turn rate of the vehicle to specified operating ranges dependent on the collision avoidance system. The controller, when the vehicle is operating in the manual mode, is configured to determine whether a position of the speed control lever corresponds to a wheel motor speed that falls within a speed tolerance, and to inhibit movement of the vehicle in response to the wheel motor speed falling outside of the speed tolerance.

[0075] FIGS. 2A and 2B are block diagrams that illustrate various components of a control system 200 of a grounds working vehicle 100, such as a mower, according to embodiments described herein. The control system 200 includes a number of subsystems each of which includes various components coupled to a controller 203 via a direct connection or a CAN (Controller Area Network) bus 211. The control system 200 includes a user interface subsystem 202, a sensor subsystem 222, and an autonomous subsystem 250, a traction drive subsystem 260, a power subsystem 282, and a cutting apparatus subsystem 292.

[0076] The controller 203 may include one or more processors 205 that receive various inputs and execute one or more computer programs or applications stored in memory 207. The memory 207 may store computer-readable instructions or applications that, when executed, e.g., by the one or more processors 205, cause the controller 203 to perform various calculations and / or issue commands. That is to say, the processor(s) 205 and memory 207 maytogether define a computing apparatus operable to process input data and generate the desired output to one or more components / devices.

[0077] The controller 203 may be implemented in any manner known to one skilled in the art. The processor(s) 205 may include any one or more of a microprocessor, a digital signal processor (DSP), an application specific integrated circuit (ASIC), a field-programmable gate array (FPGA), and / or equivalent discrete or integrated logic circuitry. In some implementations, the processor(s) 205 may include multiple components, such as any combination of one or more microprocessors, one or more DSPs, one or more ASICs, and / or one or more FPGAs, as well as other discrete or integrated logic circuitry. The functions attributed to the controller 203 and / or processor(s) 205 herein may be embodied as software, firmware, hardware, or any combination of these.

[0078] The memory 207 may include any volatile, non-volatile, magnetic, optical, and / or electrical media, such as a random-access memory (RAM), read-only memory (ROM), nonvolatile RAM (NVRAM), electrically-erasable programmable ROM (EEPROM), flash memory, and / or any other digital media. While shown as both being incorporated into the controller 203, the memory 207 and the processor(s) 205 could be contained in separate modules.

[0079] The user interface subsystem 202 includes a number of components which are mounted on the frame 102 of the vehicle 100 proximate the operator controls 209. A mode switch 204 allows an operator to select between a manual mode and an autonomous mode for operating the vehicle 100. The manual mode is a setting in which the operator manually controls the vehicle 100. For example, the operator may walk or ride behind the vehicle 100 and manipulate various controls and switches to control operation of the vehicle 100 in the manual mode. The autonomous mode is a setting in which the vehicle 100 operates autonomously. For example, the vehicle 100 can be controlled without manual intervention via an autonomous control system of the vehicle 100.

[0080] A key switch 206 allows the operator to control the state of the vehicle 100 between an ON state (key inserted and turned to ON position), in which operation of the vehicle 100 can commence, and an OFF state (key turned to OFF position or removed), in which operation of the vehicle 100 is prevented. A power take-off (PTO) switch 208 allows the operator to selectively activate and deactivate the cutting apparatus 296. A fault reset button 210 allows the operator to reset one or more performance enhancement functions that have been triggeredduring operation. For example, any of the performance enhancement functions 311 shown in FIG. 3, after being triggered, can be reset by operator use of the fault reset button 210.

[0081] An emergency stop (E-stop) button 214 can be activated by the operator to immediately halt operation of the vehicle 100 to avert an actual or impending emergency. Activation of the E-stop button 214 by the operator causes removal of tractive power from both drive wheels 104 and application of the wheel brakes, kills the engine 287, stops the cutting apparatus 296, and stops the generator 288. The emergency stop function implemented by the controller 203 is active in both manual mode and autonomous mode. Once triggered, the emergency stop function requires a reset input action by the operator using the fault reset button 210.

[0082] An auto start button 216 allows the operator to initiate autonomous operation of the vehicle 100. Initiating autonomous operation of the vehicle 100 involves setting the mode switch 204 to autonomous mode in addition to activation of the auto start button 216 by the operator. Autonomous operation of the vehicle 100 involves the autonomous subsystem 250 which includes autonomous control system 252. The controller 203 cooperates with the autonomous control system 252 and the GPS (Global Positioning System) sensor 240 to define a navigation system that controls the speed and direction of the vehicle 100 when operating in an autonomous mode.

[0083] A display 218 (e.g., LCD, OLED) can be situated on the frame 102 proximate the operator controls 209. Various types of information can be presented on the display 218 including visual alarms 212. Audible alarms 212 can be broadcast to the operator via a speaker situated proximate the operator controls 209. Other information, such as operating conditions / status of the vehicle 100 and instructions for implementing various functions of the vehicle 100, can be presented on the display 218.

[0084] For example, instructions for creating a working area boundary for autonomous operation of the vehicle 100 can be presented on the display 218. An alphanumeric keypad 217 can be used by the operator to respond to questions presented on the display 218. A message presented on the display 218 can query whether the operator wishes to create a working area boundary to define a working area for automated operations. The operator can enter an input (Y for yes) using the keypad 217 to answer in the affirmative. Another message can be presented on the display 218 to query whether the operator has moved the vehicle 100 to a starting location for creating the working area boundary. After responding in the affirmative using the keypad 217, the operator can maneuver the vehicle 100 along a path to define theworking area boundary. While traversing the path, geographic locations are recorded by the controller 203 using the GPS sensor 240.

[0085] A further message can be presented on the display 218 to query whether the operator has moved the vehicle 100 to a location which closes the working area boundary. In response to an affirmative input using the keypad 217, the geographic locations recorded by the controller 203 which define the working area boundary are stored in memory 207. A message can be presented on the display 218 to query whether the operator wishes to keep or discard the working area boundary data stored in memory 207. This process can be repeated for defining one or more exclusion zones within the working area. An exclusion zone is an area defined by the operator where the vehicle 100 is not permitted to perform automated operations, which overlaps in part or in whole with the working area.

[0086] The sensor subsystem 222 includes the LH OPC 224 and the RH OPC 228. A LH lever sensor 226 measures displacement of the LH control lever 225, and a RH lever sensor 230 measures displacement of the RH control lever 229. A tilt sensor 232 is situated on the frame 102 to measure the tilt of the vehicle relative to horizontal (a plane orthogonal to the direction of gravity). The tilt sensor 232 can include one or more of an accelerometer, gyroscope, magnetometer, and an inertial measurement unit (IMU). A sulky position sensor 234 (e.g., a proximity or contact sensor) detects when the sulky 120 is in a stowed position or moved away from the stowed position. When the sulky position sensor 234 detects that the sulky 120 has been moved away from the stowed position (e.g., moved to the deployed position), autonomous operation of the vehicle 100 is prevented by the controller 203.

[0087] The sensor subsystem 222 includes a radar control unit 236 coupled to a number of radar units 238. According to some embodiments, the radar control unit 236 is coupled to three radar units 238. A first radar unit is mounted on the frame 102 as a forward-looking radar. A second radar unit is mounted on the frame 102 as a left-side looking radar. A third radar unit is mounted on the frame 102 as a right-side looking radar. The radar units 238 are used by a collision avoidance system 308 of the vehicle 100 (see discussion below).

[0088] The vehicle 100 may further include one or more sensors to provide location data. For example, a GPS sensor 240 (or other position sensor that may provide similar data) may be used to estimate a position of the vehicle 100, such as a position within a work area, and provide such information to the controller 203. In some embodiments, the GPS data generated by the GPS sensor 240 may be augmented using a GPS-specific correction data, such as realtime kinematics (RTK) data. GPS-RTK data may provide a more accurate or precise locationthat corrects for anomalies in GPS timing compared to nominal GPS data. In some embodiments, one or both of the drive wheels 104 may include encoders that provide wheel rotation / speed information that may be used to estimate vehicle position (e.g., based upon an initial start position) within a given work region.

[0089] When the vehicle 100 is operating in an autonomous mode, for example, the processor(s) 205 may receive various input data including positional data from the GPS sensor 240 and / or wheel encoders and generate speed and steering angle commands to one or both drive wheel motors to cause the drive wheels 104 to rotate at a specified speed and direction. In other words, the controller 203 may control the steering angle and speed of the vehicle 100, as well as the speed and operation of the cutting apparatus 296.

[0090] As is shown in FIG. 2B, the traction drive subsystem 260 includes a LH wheel drive system 261 and a RH wheel drive system 271. The LH wheel drive system 261 includes a LH motor 262 coupled to a LH drive wheel 266 via a gearbox 264. A LH wheel speed sensor 267 is configured to measure a speed of the LH drive wheel 266. The LH motor 262 is monitored and controlled by an LH traction controller 270. The LH traction controller 270 also controls a brake relay 268 for activating and deactivating application of a brake to the LH motor 262. The LH traction controller 270 is coupled to the controller 203 via CAN bus 211.

[0091] The RH wheel drive system 271 includes a RH motor 272 coupled to a RH drive wheel 276 via gearbox 274. A RH wheel speed sensor 277 is configured to measure a speed of the RH drive wheel 276. The RH motor 272 is monitored and controlled by a RH traction controller 280. The RH traction controller 280 also controls a brake relay 278 for activating and deactivating application of a brake to the RH motor 272. The RH traction controller 280 is coupled to the controller 203 via CAN bus 211.

[0092] The power subsystem 282 includes a gas engine 287 coupled to a low voltage (e.g., 12V) battery via a start relay 285, a run relay 286, and a disconnect switch 290. The gas engine 287 is coupled to a generator 288. The generator 288 is coupled to a contactor 289 and communicatively coupled to the controller 203 via CAN bus 211. The contactor 289 is coupled to the LH and RH traction controllers 270, 280. A high voltage (e.g., 48V) battery is coupled to the contactor 289 via the disconnect switch 290. The disconnect switch 290 can be controlled by the controller 203 to disconnect the LV battery 284 from the gas engine 287 and the HV battery 283 from the contactor 289, thereby removing power from the gas engine 287 (and therefore the generator 288), traction drive subsystem 260, and cutting apparatus 296.

[0093] The cutting apparatus subsystem 292 includes a PTO clutch 294 coupled to the gas engine 287 and the RH traction controller 280. The PTO clutch 294 controls activation and deactivation of the cutting apparatus 296 (e.g., cutting blades). A cutting apparatus speed sensor 298 is configured to measure a speed of the cutting apparatus 296 (e.g., cutting blade speed).

[0094] FIG. 3 illustrates a number of performance enhancement functions 311 which can be implemented by a controller 203 of a grounds working vehicle 100 in accordance with various embodiments. The controller 203 is shown coupled to various components 301 of the vehicle 100, such that particular components 301 are used by the controller 203 when implementing particular ones of the performance enhancement functions 311.

[0095] The controller 203 is coupled to a propulsion system 303, which includes the traction drive subsystem 260 and the power subsystem 282 shown in FIG. 2B. The controller 302 is also coupled to a positioning sensor 304, which includes GPS sensor 240 shown in FIG. 2A. The controller 302 is further coupled to a navigation system 306, which includes the autonomous control system 252 and the positioning sensor 304. A collision avoidance system 308 of the vehicle 100 is implemented by the controller 203 in cooperation with radar units 238 and the radar control unit 236. The cutting apparatus 296 of the cutting apparatus subsystem 292 is also controlled by the controller 203. The controller 203 is further coupled to mode switch 204, sulky position sensor 234, tilt sensor 232, and PTO switch 208.

[0096] The controller 203 can be configured to implement a drive monitoring function 310 during manual operation of the grounds working vehicle 100. In general terms, the drive monitoring function 310 is implemented by the controller 203 to ensure that the vehicle 100 is moving in the way the operator intends. While in manual mode, and the operator presence control devices (LH OPC 224, RH OPC 228) are active, the drive monitoring function 310 ensures that the motor speed of each drive wheel, as measured by the LH and RH wheel speed sensors 267, 277, is within a specified tolerance of the speed commanded by the operator via a control lever (LH control lever 225, RH control lever 229). For example, the specified tolerance can be a wheel motor speed that is within 25% of the speed commanded by the operator or 0.25 mph, whichever is greater. The drive monitoring function 310 is implemented by the controller 203 to remove power to the drive wheels and engage wheel brakes to inhibit vehicle movement in response to the wheel motor speed falling outside of the speed tolerance.

[0097] The drive monitoring function 310 can be implemented by the controller 203 to limit the acceleration and deceleration of the vehicle 100 while operating in the manual mode.For example, the controller 203 can limit the acceleration of the vehicle 100 to 2.2 m / s (5.0 mph / s) and limit the deceleration of the vehicle 100 by 2.2 m / s (5.0 mph / s).

[0098] If a violation of the drive monitoring function 310 is triggered, the drive monitoring function 310 initiates stoppage of the traction drive subsystem 260 by the controller 203 (e.g., removing power to the drive wheels and engaging wheel brakes to inhibit vehicle movement). A visual indication that the drive monitoring function has been triggered can be provided to the operator via the display 218. The drive monitoring function 310 can be reactivated by a manual reset input action using the fault reset button 210 of the user interface subsystem 202.

[0099] The controller 203 can be configured to implement a speed limiting function 312 during manual and autonomous operation of the grounds working vehicle 100. In general terms, the speed limiting function 312 is implemented by the controller 203 to ensure that the vehicle 100 does not exceed a maximum safe traveling speed in either the forward direction or the rearward direction. In the autonomous mode, the speed limiting function 312 ensures that the speed and the turn (yaw) rate of the vehicle 100 is limited to be within operating ranges that are protected by the collision avoidance function 322 (see, e.g., FIGS. 4 and 5). In other words, the speed limiting function 312 in autonomous mode limits the speed and the turn rate of the vehicle 100 to specified operating ranges that allow the collision avoidance system 308 to avoid a collision between the vehicle 100 and an object in the path of the vehicle 100. As discussed below, the collision avoidance system 308 includes sensors (e.g., radar units) that can detect an object ahead and lateral of the vehicle 100. In response to detecting an object ahead or lateral of the vehicle 100, the collision avoidance system 308 causes the vehicle 100 to reduce speed and / or immediately stop (depending on the distance between the object and the vehicle 100) prior to contacting the object.

[0100] While operating the vehicle 100 in a manual mode, the speed limiting function 312 is implemented by the controller 203 to ensure that the forward wheel speed does not exceed a specified speed, such as 3.35 m / s (7.5 mph). In addition, the controller 203 implements the speed limiting function 312 to ensure that the rearward wheel speed does not exceed a specified speed, such as 1.34 m / s (3 mph) while operating the vehicle 100 in manual mode.

[0101] While the vehicle 100 is operating in an autonomous mode, the speed limiting function 312 is implemented by the controller 203 to ensure that the vehicle 100 does not travel in the reverse direction, such that an average of the two drive wheel speeds is never in the reverse direction (since vehicle travel in the reverse direction is considered unnecessary for automated operations). Although travel in the reverse direction is prevented by the speedlimiting function 312 while operating the vehicle 100 in autonomous mode, this function allows the vehicle 100 to implement a zero-turn-radius pivot, where one drive wheel rotates backwards and the other drive wheel rotates forward at the same speed, such that a midpoint between the two drive wheels rotates above a fixed ground location. The speed limiting function 312 can also allow for the forward turning wheel to exceed the rearward turning wheel such that the turn center may be at some point (e.g., anywhere) between the drive wheels (e.g., not necessarily a midpoint) and dynamic (e.g., a moving ground location or generally fixed location).

[0102] While the vehicle 100 is operating in an autonomous mode, the speed limiting function 312 is implemented by the controller 203 to ensure that the average travel speed of the vehicle 100 in the forward direction does not exceed a specified speed, such as 2.25 m / s (5 mph). It is noted that the average travel speed of the vehicle 100 is defined as the average of the two drive wheel speeds.

[0103] The controller 203 can be configured to implement a travel prevention function 314 during manual and autonomous operation of the grounds working vehicle 100. In general terms, the travel prevention function 314 is implemented by the controller 203 to ensure that the grounds working vehicle 100 does not move unless the operator has shown a deliberate intention to move the vehicle 100 manually or initiate autonomous operation of the vehicle 100.

[0104] In order to operate the vehicle 100 in manual mode, the travel prevention function 314 requires activation of the operator presence control devices (LH OPC 224, RH OPC 228) before the traction drive subsystem 260 of the vehicle 100 can be activated. While in manual mode, the travel prevention function 314 automatically activates stoppage of the traction drive subsystem 260 when the operator releases the operator presence control devices.

[0105] The travel prevention function 314 implemented by the controller 203 only allows automated motion control of the vehicle 100 in response to the mode switch 204 being set to autonomous mode. The travel prevention function 314 only allows automated motion control of the vehicle 100 if the operator presence control devices are not being activated by an operator. Also, the travel prevention function 314 activates stoppage of the traction drive subsystem 260 if the mode, as determined by the setting of the mode switch 204, is changed while the vehicle 100 is in motion.

[0106] The controller 203, when implementing the travel prevention function 314, ensures that starting of the engine 287 does not cause the vehicle 100 to move. Also, the travelprevention function 314 ensures that the vehicle 100 does not move while the engine 287 is not running.

[0107] The travel prevention function 314 is triggered if any of the functional requirements listed above are not met. When triggered, the travel prevention function 314 activates stoppage of the traction drive subsystem 260, such that tractive power is removed from both drive wheels and wheel brakes are applied to inhibit vehicle movement. Once triggered, the travel prevention function 314 requires a manual reset input action, via the fault reset button 210 of the user interface subsystem 202.

[0108] A power take-off control function 316 can be implemented by the controller 203 to ensure that the PTO facility of the vehicle 100 has not been engaged unless the operator has shown deliberate intention to engage the PTO facility or initiate automatic operations. As previously discussed with reference to FIG. 2B, the engine 287 of the vehicle 100 can transmit power to the cutting apparatus 296 via PTO clutch 294. If the PTO facility is engaged, power is transmitted to the cutting apparatus 296. If the PTO facility is disengaged, no power is transmitted to the cutting apparatus 296 and a brake is applied, stopping the cutting apparatus 296. The operator demonstrates the intent to engage the PTO facility using the PTO switch 208 of the user interface subsystem 202 which includes two positions, OFF and ON.

[0109] When in manual mode, the controller 203 ensures that the operator presence controls are activated by the operator before the cutting apparatus 296 can be activated. Movement of the cutting apparatus 296 is halted within a specified time period (e.g., within 5 seconds) upon deactivation of the PTO switch 208 (setting the PTO switch 208 to the OFF position). Also, movement of the cutting apparatus 296 is halted within a specified time period (e.g., within 5 seconds) when the operator releases an operator presence control.

[0110] When operating the vehicle 100 in an autonomous mode, the cutting apparatus 296 is activated following the operator switching the mode switch 204 to autonomous mode. When in an autonomous mode, movement of the cutting apparatus 296 is halted within a specified time period (e.g., within 5 seconds) when the operator activates an operator presence control or moves the PTO switch 208 to ON. When the mode switch 204 is changed from autonomous mode to manual mode or vice versa, the power take-off control function 316 halts movement of the cutting apparatus 296 within a specified time period (e.g., within 5 seconds).[OHl] When the power take-off control function 316 is triggered, a manual reset of the PTO control function 316 is required by activation of the fault reset button 210 of the user interface subsystem 202. It is noted that the cutting apparatus 296 is not reactivated uponmanually resetting the PTO control function 316, but requires the operator to switch the PTO switch 208 to ON or initiate automatic operation of the vehicle 100.

[0112] The controller 203 can be configured to implement an excessive tilt function 318 during autonomous operation of the grounds working vehicle 100. In general terms, the excessive tilt function 318 ensures that the grounds working vehicle 100 does not continue to operate in an autonomous mode once the tilt of the vehicle 100 exceeds a specified tilt threshold (e.g., a tilt of 3 degrees or greater relative to horizontal). When the specified tilt threshold is exceeded during autonomous operation of the vehicle 100, power is removed from the drive wheels and wheel brakes are applied to inhibit vehicle movement. After the excessive tilt function 318 is triggered, continued operation of the vehicle 100 requires a manual reset, via the fault reset button 210 of the user interface subsystem 202, or a mode change, via mode switch 204.

[0113] The controller 203 can be configured to implement a sulky rider prevention function 322 which prevents autonomous operation of a grounds working vehicle 100 if the sulky 120, coupled to the vehicle 100, is in a position where an operator can ride on it. As is shown in FIG. 1, the vehicle 100 can include optional sulky 120 which is coupled to a rear portion of the frame 102. The sulky 120 can be moved between a stowed position and a deployed position. When deployed, the sulky allows the operator to ride behind the vehicle 100 while operating the vehicle 100 in manual mode. To stow the sulky 120, the sulky 120 is rotated upwardly towards the rear portion of the frame 102 and captured by a retention arrangement which holds the sulky 120 against the frame 102. The operator is unable to ride the sulky 120 when stowed. A sulky position sensor 234 (e.g., a proximity or contact sensor), coupled to the controller 203, detects when the sulky 120 is in the stowed position or moved away from the stowed position.

[0114] The sulky rider prevention function 322 ensures that the vehicle 100 does not operate in autonomous mode when the sulky 120 is deployed. If the sulky 120 is deployed from its stowed position and autonomous mode is selected via the mode switch 204, the sulky rider prevention function 322 is triggered and the vehicle 100 is prevented from moving (e.g., the traction drive subsystem 260 is deactivated and drive wheel brakes are engaged to inhibit vehicle movement). A visual indicator to the operator is presented on the display 218 when the sulky rider prevention function 322 is triggered. Triggering of the sulky rider prevention function 322 can be cleared by a manual reset via the fault reset button 210 of the user interface subsystem 202.

[0115] The controller 203 can be configured to implement a collision avoidance function 322 during autonomous or manual operation of a grounds working vehicle 100. For example, the collision avoidance function 322 may be active when operating the vehicle 100 in an autonomous mode. The primary purpose of the collision avoidance function 322 is to mitigate the risks associated with a person or object being too close to the vehicle 100 (e.g., during automated operations), which necessarily involves the vehicle 100 travelling in a predetermined work area and operation of the cutting apparatus 296 in the case of a vehicle 100 equipped with a cutting deck. The collision avoidance function 322 monitors the travel motion of the vehicle 100 and detects persons or objects close to the vehicle 100. The collision avoidance function 322 prevents harmful contact by restricting or ceasing hazardous vehicle motion if a person or object is detected close enough, based on current vehicle operations, to be at risk of harmful contact.

[0116] The vehicle 100 can be described as having a collision hazard zone, which can be defined as the area around the vehicle 100 where a person or stationary object is at risk of contact with the moving vehicle 100, assuming the vehicle 100 immediately initiates a protective stopping action to avoid such a collision or contact. In other words, the collision hazard zone includes the entire travel area that would be traversed before the vehicle’s hazardous movement ceases.

[0117] The size of the collision hazard zone is a characteristic of the vehicle’s stopping capabilities and is based on several factors. A first factor is the maximum distance the vehicle 100 will travel during a stopping action over the range of operating speeds, taking into account the operating environment, such as strain slope, load variations, irrigation conditions, etc. A second factor is the current speed and direction of vehicle travel, which, when combined with stopping distance information, determines the expected track the vehicle 100 will traverse during the stopping action. A third factor is the activation time required for the collision avoidance function’s logic and signaling to issue a stop command and begin the stopping action.

[0118] The collision hazard zone of the vehicle 100 can include an outer hazard zone and an inner hazard zone. If the collision avoidance system 308 detects a person or object within the outer hazard zone, the controller 203 causes the vehicle 100 to decelerate to a reduced speed, which results in a new smaller collision hazard zone commensurate with the reduced speed target. For example, the collision avoidance function 322 can slow the vehicle 100 to 0.75 m / s (1.67 mph) at a rate of 1 mph / s. If the collision avoidance system 308 detects a personor object within the inner hazard zone, the controller 203 brings the vehicle 100 to a standstill and also stops movement of the cutting apparatus 296.

[0119] FIG. 5 shows the vehicle 100 equipped with three radar units 238a, 238b, 238c, which are sensors used by the collision avoidance system 308. Radar unit 238a is oriented along a front direction of the vehicle 100. Radar unit 238b is oriented along a left side direction of the vehicle 100, while radar unit 238c is oriented along a right side direction of the vehicle 100. The radar units 238a, 238b, 238c are used to detect objects in their fields of view (FOV). The FOVs can be divided into user-defined zones of operation. It is noted that the vehicle 100 shown in FIG. 5 does not include a rear radar unit, since travel in reverse during autonomous operation is prevented by the speed limiting function 312. In some embodiments, a LIDAR sensor can be included which provides a 360 degree coverage in azimuth.

[0120] One or more of the radar zones can be arranged in the form of inner and outer hazard zones. The location and shape of these zones can be designed to cover specific viewing areas at the front and sides of the vehicle 100. In the illustrative example shown in FIG. 5, the FOV of the front radar 238a includes an inner hazard zone 502 and an outer hazard zone 503. The FOV of the left side radar unit 238b includes a single zone, namely inner hazard zone 505. The FOV of the right side radar unit 238c includes a single zone, namely inner hazard zone 507. It is understood the FOVs of the left side and right side radar units 238c, 238c can include inner and outer hazard zones.

[0121] The individual zone geometries and detection parameters (such as sensitivity and coverage angles) of the radar units 238a, 238b, 238c can be tailored for the particular mode that the vehicle 100 is operating in. The parameters of the zones 502, 503, 505, 507 can be changed dynamically as the vehicle changes operating modes. For example, when travelling at high speeds along straight paths, forward-looking zones 502, 503 can be made larger than when travelling at low speed. Detection of an object in an outer hazard zone (e.g., zone 503) results in a reduction of vehicle speed commanded by the controller 203. Detection of an object in an inner hazard zone (e.g., zones 502, 505, 507) results in a command initiated by the controller 203 that immediately stops the vehicle 100.

[0122] Referring again to FIG. 3, the controller 203 can be configured to implement a working area function 324 to restrict the area in which the grounds working vehicle 100 conducts automated operations to the area specified by the operator. The working area is defined as the fully-enclosed geographical area defined by an operator where the vehicle 100 can perform automated operations, with the exception of areas defined by an operator as 1exclusion zones that are not suitable for the vehicle 100 to perform automated operations due to potential hazards.

[0123] The working area is delineated by a boundary, which is defined by the outer edges of the working area that separate the operator-defined working area from areas outside of the working area. By definition, the working area boundary fully encloses the working area. A working area exclusion zone is an operator-defined area where the vehicle 100 cannot or should not perform automated operations, which overlaps in part or in whole with the working area.

[0124] Using the GPS sensor 240 during autonomous operation of the vehicle 100 within the working area, the controller 203 compares the position of the vehicle 100 to the working area boundary stored in memory 207. As discussed previously, the operator can create the working area boundary during a training mode in which the vehicle 100 is manually moved along a path while recording geographical location data. When the vehicle 100 returns to a location at or near the origin of the path (so as to close the path), the recorded geographical location data for the closed path defines the working area boundary. The working area function 324 is triggered when the controller 203 detects that the vehicle 100 moves outside of the working area (moves beyond the working area boundary).

[0125] When triggered, the working area function 324 initiates a protective stop of the vehicle 100. If the controller 203 determines that the protective stop monitoring requirements for stopping the traction drive system are not satisfied, the working area function 324 isolates power from the traction drives, brakes are applied to the drive wheels 104, and a fault condition is entered. If the protective stop monitoring requirements for stopping the cutting apparatus 296 are not satisfied, the working area function 324 isolates power from the cutting apparatus 296 (e.g., by disabling the engine 287) and a fault condition is entered.

[0126] If the position of the vehicle 100 with respect to the working area is unknown or the uncertainty in the vehicle’s position extends outside the working area, the controller 203 causes the vehicle 100 to stop and remain stationary such that movement of the vehicle 100 causes triggering of the working area function 324.

[0127] After the working area function 324 is triggered, the function 324 remains latched in the active state until the fault reset button 210 is activated by the operator or the mode switch 204 is switched to manual mode. If the working area function 324 is triggered and the vehicle 100 remains in autonomous mode, the function 324 ignores a manual reset via the fault reset button 210 until the trigger conditions are no longer present.

[0128] FIG. 4 illustrates a method 400 of operating a grounds working vehicle 100 in an autonomous mode in accordance with embodiments disclosed herein. The method 400 is directed to a grounds working vehicle 100 configured to implement a combination of performance enhancement functions, namely a speed limiting function 312 in combination with a collision avoidance function 322 (see FIG. 3). The method 400 involves enabling 402 an autonomous mode of the vehicle 100. The autonomous mode of the vehicle 100 may be enabled in response to selection of the autonomous mode by the operator via the mode switch 204 and receiving an autonomous mode activation signal by the controller 203.

[0129] The method 400 also involves limiting 404, while the vehicle 100 is operating in the autonomous mode, a speed and a turn rate of the vehicle 100 to specified operating ranges dependent on the collision avoidance system 308 of the vehicle 100. It is noted that the turn rate of the vehicle is dependent on the difference in speed of the left and right drive wheels, each of which is independently controllable by the controller 203.

[0130] The collision avoidance function 322 is active when operating the vehicle 100 in the autonomous mode, and cooperates with the speed limiting function 312 to limit the speed and turn rate to be withing operating ranges that are protected by the collision avoidance system 308 of the vehicle 100. In other words, the speed limiting function 312 ensures that the average travel speed and rotation rate of the vehicle 100 is limited to match the detection capabilities of the collision avoidance function 322.

[0131] FIG. 6 illustrates a method 600 of operating a grounds working vehicle 100 in a manual mode in accordance with embodiments disclosed herein. The method 600 is directed to a grounds working vehicle 100 configured to implement a drive monitoring function 310 (see FIG. 3). The method 600 involves enabling 602 manual mode of the vehicle 100. Manual mode of the vehicle 100 may be enabled in response to selection of manual mode by the operator via the mode switch 204.

[0132] The method 600 also involves determining 604 whether a position of a speed control lever of the vehicle 100 corresponds to a wheel motor speed that falls within a speed tolerance. The method 600 also involves removing 606 power to the drive wheels and engaging a wheel brake of the vehicle 100 to inhibit vehicle movement in response to the wheel motor speed falling outside of the speed tolerance.

[0133] FIG. 7 illustrates a method 700 of operating a grounds working vehicle 100 in an autonomous mode and a manual mode in accordance with embodiments disclosed herein. The method 700 is directed to a grounds working vehicle 100 configured to implement acombination of performance enhancement functions, namely a speed limiting function 312 in combination with a drive monitoring function 310 (see FIG. 3).

[0134] The method 700 involves enabling 702 an autonomous mode of the vehicle 100, which may be enabled in response to selection of the autonomous mode by the operator via the mode switch 204 and receiving an autonomous mode activation signal by the controller 203. When the autonomous mode is enabled 702, the speed limiting function 312 is active. The method 700 involves limiting 704, while the vehicle 100 is operating in the autonomous mode, a speed and a turn rate of the vehicle 100 to specified operating ranges dependent on the collision avoidance system 308 of the vehicle 100.

[0135] The method 700 also involves enabling 706 manual mode of the vehicle 100, which may be enabled in response to selection of manual mode by the operator via the mode switch 204. When manual mode is enabled 706, the drive monitoring function 310 is active. The method 700 involves determining 708, while the vehicle is operating in manual mode, whether a position of a speed control lever of the vehicle 100 corresponds to a wheel motor speed that falls within a speed tolerance. The method 700 also involves removing 710 power to the drive wheels and engaging a wheel brake of the vehicle 100 to inhibit vehicle movement in response to the wheel motor speed falling outside of the speed tolerance.

[0136] FIG. 8 illustrates a method 800 of operating a grounds working vehicle 100 in an autonomous mode and a manual mode in accordance with embodiments disclosed herein. The method 800 is directed to a grounds working vehicle 100 configured to implement a combination of performance enhancement functions, namely a speed limiting function 312 in combination with a drive monitoring function 310 (see FIG. 3).

[0137] The method 800 involves selectively enabling 802 the autonomous mode or manual mode of operating a grounds working vehicle 100 in response to selection of the autonomous mode or manual mode by the operator via the mode switch 204. When the autonomous mode is enabled 804, the speed limiting function 312 is active. The speed limiting function 312 operates to limit 806 a speed and a turn rate of the vehicle to specified operating ranges dependent on a collision avoidance system 308 of the vehicle 100. The speed limiting function 312 also prevents 808 travel of the vehicle 100 in reverse but permits a zero-turn-radius pivot of the vehicle 100.

[0138] When manual mode is enabled 810, the speed limiting function 312 operates to prevent 812 forward and reverse drive wheel speeds of the vehicle 100 from exceeding maximum forward and reverse speeds, respectively. The drive monitoring function 310determines 814 whether a position of a speed control lever of the vehicle corresponds to a wheel motor speed that falls within a speed tolerance. The drive monitoring function 310 also removes 816 power to the drive wheels and engages a wheel brake to inhibit vehicle movement in response to the wheel motor speed falling outside of the speed tolerance.

[0139] In some embodiments, a grounds working vehicle 100 may include a communication system that permits the vehicle 100 / controller 203 to operatively communicate (e.g., via a wireless radio) with a communication network such as a wireless network, thereby allowing communication (e.g., bidirectional communication) between the vehicle 100 and other devices. For example, the wireless network may be a cellular or other wide area network, a local area network (e.g., an IEEE 802.11 local “Wi-Fi” network), or a personal area or peer- to-peer network (“P2P,” e.g., “Bluetooth” network). Other devices may communicate over the wireless network with the vehicle 100, including, for example, a remote computer, which may be configured as a mobile / cellular phone, tablet, desktop computer or notebook computer. Preferably, the wireless network is connected to the Internet so that the operator / remote computer may interact with the communication system of the vehicle 100 regardless of the operator’s location. Moreover, connection of the wireless network to the Internet allows communication with most any other remote computer including, for example, an Internet (cloud)-based server.

[0140] While the present disclosure is not so limited, an appreciation of various aspects of the disclosure will be gained through a discussion of the specific illustrative aspects provided herein. Various modifications of the illustrative aspects, as well as additional aspects of the disclosure, will become apparent herein.

[0141] Although reference is made herein to the accompanying set of drawings that form part of this disclosure, one of at least ordinary skill in the art will appreciate that various adaptations and modifications of the embodiments described herein are within, or do not depart from, the scope of this disclosure. For example, aspects of the embodiments described herein may be combined in a variety of ways with each other. Therefore, it is to be understood that, within the scope of the appended claims, the claimed embodiments may be practiced other than as explicitly described herein.

[0142] All scientific and technical terms used herein have meanings commonly used in the art unless otherwise specified. The definitions provided herein are to facilitate understanding of certain terms used frequently herein and are not meant to limit the scope of the present disclosure.

[0143] The recitation of numerical ranges by endpoints includes all numbers subsumed within that range (e.g., 1 to 5 includes 1, 1.5, 2, 2.75, 3, 3.80, 4, and 5) and any range within that range. Herein, the terms “up to” or “no greater than” a number (e.g., up to 50) includes the number (e.g., 50), and the term “no less than” a number (e.g., no less than 5) includes the number (e.g., 5).

[0144] The terms “coupled” or “connected” refer to elements being attached to each other either directly (in direct contact with each other) or indirectly (having one or more elements between and attaching the two elements). Either term may be modified by “operatively” and “operably,” which may be used interchangeably, to describe that the coupling or connection is configured to allow the components to interact to carry out at least some functionality.

[0145] Reference to “one embodiment,” “an embodiment,” “certain embodiments,” or “some embodiments,” etc., means that a particular feature, configuration, composition, or characteristic described in connection with the embodiment is included in at least one embodiment of the disclosure. Thus, the appearances of such phrases in various places throughout are not necessarily referring to the same embodiment of the disclosure.Furthermore, the particular features, configurations, compositions, or characteristics may be combined in any suitable manner in one or more embodiments.

[0146] As used in this specification and the appended claims, the singular forms “a,” “an,” and “the” encompass embodiments having plural referents, unless the content clearly dictates otherwise. As used in this specification and the appended claims, the term “or” is generally employed in its sense including “and / or” unless the content clearly dictates otherwise.

Claims

CLAIMSWhat is claimed is:

1. A method of operating a grounds working vehicle, comprising: enabling an autonomous mode of the vehicle; and while the vehicle is operating in the autonomous mode, limiting a speed and a turn rate of the vehicle to specified operating ranges dependent on a collision avoidance system of the vehicle.

2. The method according to claim 1, wherein limiting the turn rate of the vehicle comprises limiting a rate of a zero-turn-radius turn of the vehicle to a maximum turn rate.

3. The method according to claim 2, comprising preventing travel of the vehicle in reverse but permitting the zero-tum-radius turn of the vehicle.

4. The method according to any one of claims 1-3, wherein the turn rate of the vehicle is dependent on a difference in speed of left and right drive wheels of the vehicle.

5. The method according to any one of claims 1-4, comprising preventing forward and reverse drive wheel speeds of the vehicle from exceeding maximum forward and reverse speeds, respectively.

6. The method according to any one of claims 1-5, wherein the autonomous mode is enabled in response to selection of the autonomous mode and receiving an autonomous mode activation signal.

7. The method according to any one of claims 1-6, wherein limiting the speed and the turn rate of the vehicle to the specified operating ranges allows the collision avoidance system to avoid a collision between the vehicle and an object in a path of the vehicle.

8. The method according to any one of claims 1-7, comprising disabling the autonomous mode of the vehicle in response to detecting presence of an operator at an operator position of the vehicle.

9. The method according to any one of claims 1-8, comprising disabling the autonomous mode of the vehicle in response to detecting deployment of a towable operator platform of the vehicle.

10. The method according to any one of claims 1-9, wherein the collision avoidance system senses regions ahead and lateral of the vehicle using one or more sensors.

11. A grounds working vehicle, comprising: a propulsion system; a positioning sensor; a navigation system operably coupled to the positioning sensor and the propulsion system; a collision avoidance system; a controller operably coupled to the propulsion system, the positioning sensor, the navigation system, and the collision avoidance system; and the controller, when the vehicle is operating in an autonomous mode, is configured to limit a speed and a turn rate of the vehicle to specified operating ranges dependent on the collision avoidance system.

12. The vehicle according to claim 11, wherein the controller, in the autonomous mode, is configured to limit a rate of a zero-turn-radius turn of the vehicle to a maximum turn rate dependent on the speed of the vehicle.

13. The vehicle according to claim 12, wherein the controller, in the autonomous mode, is configured to prevent travel of the vehicle in reverse but permit the zero-tum-radius turn of the vehicle.

14. The vehicle according to any one of claims 11-13, wherein the turn rate of the vehicle is dependent on a difference in speed of left and right drive wheels of the vehicle.

15. The vehicle according to any one of claims 11-14, comprising a mode switch that facilitates selection between an autonomous mode and a manual mode of operating the vehicle.

16. The vehicle according to any one of claims 11-15, wherein the controller, in the autonomous mode, is configured to prevent forward and reverse drive wheel speeds of the vehicle from exceeding maximum forward and reverse speeds, respectively.

17. The vehicle according to any one of claims 11-16, wherein the controller, in the autonomous mode, is configured to limit the speed and the turn rate of the vehicle to the specified operating ranges to allow the collision avoidance system to avoid a collision between the vehicle and an object in a path of the vehicle.

18. The vehicle according to any one of claims 11-17, wherein the controller is configured to disable the autonomous mode in response to detecting presence of an operator at an operator position of the vehicle.

19. The vehicle according to any one of claims 11-18, comprising a towable operator platform, wherein the controller is configured to disable the autonomous mode in response to detecting deployment of the towable operator platform.

20. The vehicle of any one of claims 11-19, wherein the collision avoidance system is configured to sense regions ahead and lateral of the vehicle using one or more sensors.

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