AUTOMATIC MODE FOR OBJECT DETECTION RANGE SETTING

Methods and apparatus are provided for automatically changing an obstacle detection range setting of an obstacle detection system based at least in part on a determination of a change in work state of a self-propelled vehicle. The change in work state may be a change from a transport state in which the vehicle is moving across a ground surface, to a stationary operating state. Upon detecting a change to a stationary operating state the obstacle detection range may be automatically changed to a shorter range. Upon detecting a change to a transport state the obstacle detection range may be automatically changed to a longer range.

FIELD OF THE DISCLOSURE

The present disclosure relates to methods of detecting obstacles in a working area of a self-propelled work vehicle.

BACKGROUND

A work vehicle such as an excavator is known to include an imaging system providing a surround view (bird's eye view) that displays on a touchscreen display. The excavator includes an object or obstacle detection system that detects objects up to some distance from the machine. The object detection system sends the coordinates of an object to the display which visually shows the relative location of the object to the machine and generates an audible tone. A maximum detection range can be manually adjusted through the display. The detection range can be set for example to a long, a medium, or a short range.

During normal excavation operation when the machine is stationary the operator is aware of the general surroundings of the machine and may want the detection range to be just outside the machine's swing radius or swing angle. During repositioning of the machine when the excavator is moving across a ground surface the operator may want maximum detection coverage around the machine and may manually switch the detection range to the long range.

There is a need for improved control systems which may assist the operator in switching between detection ranges.

SUMMARY OF THE DISCLOSURE

In one embodiment a method of detecting obstacles in a working area of a self-propelled work vehicle comprises steps of:(a) receiving work state signals from one or more machine parameter sensors corresponding to a work state of the work vehicle, wherein different combinations of work state signal values correspond to different ones of a plurality of work states of the work vehicle;(b) determining a change in the work state based at least in part on the work state signals;(c) receiving obstacle signals from one or more obstacle sensors corresponding to a detected presence or absence of an obstacle within an object detection range relative to the work vehicle; and(d) automatically adjusting the object detection range based at least in part on the determined change in the work state.

In a further embodiment a self-propelled work vehicle may include a machine frame, a plurality of wheels or tracks supporting the machine frame from a ground surface, at least one of the wheels or tracks being powered to propel the work vehicle, and one or more work implements supported from the machine frame. The vehicle may further include one or more machine parameter sensors configured to generate work state signals corresponding to a work state of the work vehicle and one or more obstacle sensors configured to generate obstacle signals corresponding to a detected presence or absence of obstacles within an object detection range relative to the work vehicle. An imaging system may be configured to display an image of the working area at an operator's station of the work vehicle and to display a relative location of a detected object in the image of the working area. A controller may be communicatively linked to the one or more machine parameter sensors and the one or more obstacle sensors, and configured to:receive work state signals from the one or more machine parameter sensors corresponding to the work state of the work vehicle;determine a change in the work state based at least in part on the work state signals;receive obstacle signals from the one or more obstacle sensors corresponding to the detected presence or absence the obstacles within the object detection range relative to the work vehicle; andgenerate output signals to adjust the object detection range based at least in part on the determined change in the work state.

Numerous objects, features and advantages of the present invention will be readily apparent to those skilled in the art upon a review of following description in conjunction with the accompanying drawings.

DETAILED DESCRIPTION

Referring now to the drawings and particularly toFIG.1, a representative work vehicle is shown and generally designated by the number100.FIG.1shows a tracked excavator machine100. A second exemplary work vehicle in the form of a skid steer loader is shown inFIG.2and indicated by the number200.

The systems disclosed herein are applicable to similar or otherwise equivalent vehicles, excavator machines, loaders, and other working machines of the type having one or more working implements for modifying the proximate terrain. Work vehicles as discussed herein may typically have tracked or wheeled ground engaging units supporting the undercarriage from the ground surface.

The illustrated and exemplary work vehicle100ofFIG.1includes an undercarriage102which may also be referred as a machine frame102. Vehicle100includes two tracked ground engaging units104for supporting the machine frame102from a ground surface106. Each of the tracks is powered by a track drive to propel the vehicle102.

An upper frame108is supported by the undercarriage102via a swing bearing110such that the upper frame108is pivotable about a pivot axis112relative to the undercarriage. The pivot axis112is substantially vertical when the ground surface106engaged by the ground engaging units104is substantially horizontal. A swing motor (not shown) is configured to pivot the upper frame108on the swing bearing110about the pivot axis112relative to the undercarriage102.

The work vehicle as disclosed herein typically includes one or more working implements114which as illustrated for example inFIG.1may collectively define a boom assembly114including a boom116, an arm118pivotally connected to the boom116, and a working tool120. The boom116in the present example is pivotally attached to the upper frame108to pivot about a generally horizontal axis relative to the upper frame108. The working tool in this embodiment is an excavator shovel or bucket120which is pivotally connected to the arm118. The boom assembly114extends from the upper frame108along a working direction of the boom assembly. The working direction can also be described as a working direction of the boom.

A boom cylinder122controls pivotal movement of the boom116relative to the upper frame108. An arm cylinder124controls pivotal movement of the arm118relative to the boom116. A bucket cylinder126controls pivotal movement of the bucket120relative to the arm118.

An operator's cab128may be located on the upper frame108. The operator's cab128and the one or more working implements114may both be mounted on the upper frame108so that the operator's cab faces in the working direction of the working implements. A control station including a user interface130may be located in the operator's cab. A display132may be located in the operators cab128.

As shown inFIG.2ground engaging units for the skid steer loader200include a pair of front wheels202and a pair of rear wheels204. The work vehicle200may further include at least one drive unit (not shown) including for example a travel motor for driving the respective ground engaging units. In a conventional skid steer loader, the operator can manipulate controls to drive the left-side wheels and the right-side wheels at different speeds to thereby steer the work vehicle. While the left-side wheels and the right-side wheels in such a configuration are typically maintained in a longitudinal orientation with respect to the machine frame, the vehicle is nonetheless capable of rotation in substantially a zero-degree radius about a vertical axis.

A lift mechanism for the work vehicle200may typically include one or more work implements206such as a loader bucket pivotally coupled to a forward portion of an arm208on either side of the work vehicle, wherein the arms are themselves further connected to respective side portions210of a machine frame212and pivotable about at least one generally horizontal axis214relative to the main frame212.

An operator's cab216may be located on the main frame212. The operator's cab216and the one or more working implements206may both be mounted on the main frame212so that the operator's cab216faces in the working direction of the working implements206. A control station including a user interface218and a display220may be located in the operator's cab216.

Either of the work vehicles100or200may include an imaging system.FIG.3schematically represents a bird's eye imaging system300installed on the work vehicle200. A single Bird's Eye View may be stitched from images obtained from the several cameras302.

Referring toFIG.3, such an embodiment is implemented using four cameras302, but alternative configurations may be desirable for certain types of work vehicles and are fully considered within the scope of the present disclosure. The four cameras may include a first camera302amounted on a left side of the work vehicle and arranged to capture a first viewing area304, a second camera302bmounted on a front side of the work vehicle and arranged to capture a second viewing area306, a third camera302cmounted on a right side of the work vehicle and arranged to capture a third viewing area308, and a fourth camera302dmounted on a rear side of the work vehicle and arranged to capture a fourth viewing area310. The viewing areas304,306,308and310may collectively make up a working area311around the work vehicle200.

The position and size of the viewing area recorded by a respective camera302may typically depend on the arrangement and orientation of the camera on the machine frame and further on the camera lens system, in particular the focal length of the lens of the camera.

The positions and sizes of the viewing areas inFIG.3should accordingly only be considered as exemplary, as they will vary for any number of parameters in a particular implementation. In an embodiment, each camera may be fastened to the machine frame at a specific setting angle in relation to the plane of the machine frame, so that the viewing direction of the camera is inclined downwardly in a sloping manner to the ground surface when the machine frame is oriented parallel to the ground surface. Whereas each camera302a,302b,302c,302dwould record a substantially rectangular image detail of the ground surface if the viewing direction of the camera was orthogonal to the ground surface, in accordance with the above-referenced setting angles a trapezoidal image region of the ground surface is recorded by each camera. The course of the Bird's Eye View stitching may depend on the position and size of the overlapping trapezoidal image details312,314,316and318.

The terms “left”, “right”, “front”, and “rear” as used herein may refer to the conventional use of the terms relative to a working direction of the work vehicle. In other words, for a skid-steer loader having a work implement as illustrated, the front side of the vehicle would correspond to a leading edge of the vehicle when traveling in a working direction. However, the terms are not intended as limiting on the scope of the disclosure, and alternative arrangements are reasonably contemplated.

FIG.4schematically shows the display132or220of the work vehicles100or200. This display may be located in the respective operator's cabins of the vehicles and may include a forward display screen400showing the view in the forward working direction from the operator's cabin, and a rearward display screen402showing the view in the rearward direction from the operator's cabin.

As schematically illustrated inFIG.5, the work vehicle100or200includes a control system500including a controller502. The controller502may be part of the machine control system of the work vehicle, or it may be a separate control module. The controller may include the user interface130or218and optionally be mounted in the operators cab128or216at a control panel.

The controller502is configured to receive input signals from some or all of various sensors collectively defining a sensor system504. The sensor system may include one or more machine parameter sensors506and one or more obstacle sensors508.

The machine parameter sensors506may be configured to detect machine operating conditions or positioning, including for example an orientation sensor, global positioning system (GPS) sensors, vehicle speed sensors, vehicle implement positioning sensors, and the like, and whereas one or more of these sensors may be discrete in nature the sensor system may further refer to signals provided from the machine control system.

Other sensors in the sensor system504more particularly refer to a group of sensors referred to herein as object sensors or obstacle sensors508for detecting the presence or absence of an obstacle within an obstacle detection range relative to the work vehicle. Various examples of obstacle sensors508are conventionally known and may include ultrasonic sensors, laser scanners, radar wave transmitters and receivers, thermal sensors, imaging devices, structured light sensors, and other optical sensors. The types and combinations of obstacle sensors may vary for a type of work vehicle, work area, and/or application, but generally are provided and configured to optimize recognition of obstacle proximate to, or otherwise in association with, a determined working area of the vehicle. In some embodiments the obstacle sensors, which hereinafter may be referred to for illustrative but non-limiting purposes as ultrasonic sensors, may include the ability to determine an obstacle position as well as an obstacle distance.

The obstacle sensors508and the associated signal processing system may be referred to as an obstacle detection system512. The obstacle detection system512may be adjustable so as to focus on objects within a shorter range, a medium range or a longer range from the work vehicle. The human operator may be provided with a manual detection range control514as part of the user interface130or218which allows the operator to select the focus of the obstacle detection system. For example, the shorter range may be within 1 m of the machine frame, the medium range may be withing 3 m of the machine frame, and the longer range may be within 5 m of the machine frame. Other ranges may be used.

The controller502may typically produce an output to the display132or220for display to the human operator regarding the determined positions of detected objects. For example, inFIG.4an exemplary obstacle510is shown superimposed on the image of the display.

In one embodiment the controller502may include an automatic mode for object detection range setting. When the work vehicle is operating in a transport mode where the work vehicle is moving across the ground surface it may be desired to operate the obstacle detection system512having a larger or longer object detection range extending well beyond the work implements so as to detect distant obstacles well ahead of time. But when the work vehicle stops and is in an operating mode where it is manipulating the work implement it may be desired to focus the obstacle detection in the immediate vicinity of the work vehicle and particularly in the immediate vicinity of the working implement.

The operation of the work vehicle in a transport mode or transport state where the work vehicle is moving across the ground surface may be referred to as a first work state. The operation of the work vehicle in a stationary operating mode where the work vehicle is not moving across the ground surface and the work implement is moving relative to the machine frame to perform a work function may be referred to as a second work state.

The machine parameter sensors506may provide signals or data to the controller502from which the controller502may determine the work state of the work vehicle. The controller502may then determine whether there has been a change in work state and may adjust the obstacle detection range of the obstacle detection system at least in part based on the determined change in work state.

The machine parameter sensors506may include vehicle movement sensors506awhich generate signals and data indicating whether the work vehicle is moving across the ground surface. Examples of such vehicle movement sensors506ainclude throttle position sensors, speedometers, rotary sensors on the wheels or tracks, and other sensors associated with the drive train of the work vehicle.

The machine parameter sensors506may further include work implement movement sensors506bwhich generate signals and data corresponding to movement of the work implements114,206relative to the machine frames of the respective work vehicles. For example, on the excavator100, one work implement movement sensor506bmay be a boom angle sensor for measuring a swing angle of the excavator boom116about the axis112relative to the machine frame102.

The controller502includes or may be associated with a processor516, a computer readable medium518, a communication unit520, a data storage522such as for example a database network, and the aforementioned user interface130or218having a display132or220. An input/output device514, such as a keyboard, joystick or other user interface tool, which may be the previously mentioned manual detection range control514, is provided so that the human operator may input instructions to the controller. It is understood that the controller described herein may be a single controller having all of the described functionality, or it may include multiple controllers wherein the described functionality is distributed among the multiple controllers.

Various operations, steps or algorithms as described in connection with the controller502can be embodied directly in hardware, in a computer program product519such as a software module executed by the processor516, or in a combination of the two. The computer program product519can 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 medium518known in the art. An exemplary computer-readable medium can be coupled to the processor such that the processor can read information from, and write information to, the memory/storage medium. In the alternative, the medium can be integral to the processor. The processor and the medium can reside in an application specific integrated circuit (ASIC). The ASIC can reside in a user terminal. In the alternative, the processor and the medium can reside as discrete components in a user terminal.

The term “processor” 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 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 unit520may support or provide communications between the controller and external systems or devices, and/or support or provide communication interface with respect to internal components of the working machine. 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.

Data storage as discussed herein may, unless otherwise stated, generally encompass hardware such as volatile or non-volatile storage devices, drives, memory, or other storage media, as well as one or more databases residing thereon.

Automatic Mode for Object Detection Range Setting:

The controller502may be provided with an automatic mode for object detection range setting via appropriate software programming519. Such an automatic mode for object detection range setting may provide for automatic implementation of a method of detecting obstacles514in a working area surrounding the work vehicle100or200.

For example, when the work vehicle is in a transport state in which it is moving from one location to another it may be desired to detect obstacles within a first larger range so as to warn the operator of obstacles that may collide with the moving vehicle. But when the vehicle has stopped and is in a stationary operating state it may be desired to reduce the detection range to the immediate area in which the working implement may be operated, so as to focus on obstacles that may be impacted by the working implement.

FIG.6schematically shows this concept for the excavator100, in which the first longer detection range is designated by the circular boundary600, and the second shorter detection range is designated by the circular boundary602.

The controller502may examine work state signals from one or more of the machine parameter sensors506corresponding to a work state of the excavator100, wherein different combinations of work state signal values correspond to different ones of a plurality of work states of the machine.

For example, a transport work state of the excavator100may be indicated by receipt of vehicle movement signals from the vehicle movement sensors506aindicating that the excavator100is moving across the ground surface106. Vehicle movement sensors506amay include direct movement sensors such as a rotational sensor on the tracks104or a GPS sensor mounted on the vehicle100. Vehicle movement sensors506amay also include indirect indicators of vehicle movement such as a pedal command sensor, or a valve position sensor detecting the input of a vehicle movement command by the operator of the vehicle. Such an indirect vehicle movement sensor may include the detection of pedal command signals or valve command signals already present within the vehicle control system.

A stationary operating work state of the excavator100, on the other hand, may be indicated by the receipt of signals from the vehicle movement sensors506aindicating that the excavator100is not moving across the ground surface106, in combination with signals from the work implement movement sensors506bindicating that the boom assembly114and working tool120are moving relative to the machine frame102to perform working operations.

For example, the work implement movement sensors506bfor excavator100may include a boom angle detection sensor detecting rotational movement of the upper frame108relative to the machine frame102about pivot axis112. Further work implement movement sensors506bmay include position sensors detecting the extension or retraction of each of the boom cylinder122, arm cylinder124and bucket cylinder126. The boom cylinder122, arm cylinder124and bucket cylinder126may each be implemented as “smart” hydraulic cylinders having integrated positions sensors which function as the associated work implement movement sensors506b.

The controller502may receive the vehicle movement signals from the vehicle movement sensors506aand the work implement movement signals from the work implement movement sensors506b, and determine when a change in work state has occurred.

The controller502may also receive obstacle signals from the one or more obstacle sensors508corresponding to a detected presence or absence of an obstacle510within an object detection range600,602relative to the excavator100. The controller502may automatically adjust the detection range600,602based at least in part on the determined change in the work state. For example, when the controller502determines that the excavator100is in the transport state moving across the ground surface106the controller may send command signals causing the obstacle sensors508to be operative in the longer detection range600so as to maximize the information available to the operator about potential dangers to the moving vehicle. And when the controller determines that the excavator has stopped and is in a stationary operating state, the controller may send command signals causing the obstacle sensors508to be focused in the shorter detection range602in which the work implement120may move relative to the stationary machine frame102.

The basic method of detecting obstacles510in the working area of the excavator100may be described as including steps of:(a) receiving work state signals from one or more machine parameter sensors506corresponding to a work state of the work vehicle100, wherein different combinations of work state signal values correspond to different ones of a plurality of work states of the work vehicle;(b) determining a change in the work state based at least in part on the work state signals;(c) receiving obstacle signals from one or more obstacle sensors508corresponding to a detected presence or absence of an obstacle510within an object detection range relative to the work vehicle100; and(d) automatically adjusting the object detection range600,602based at least in part on the determined change in the work state.

In the method described above, the work state signals in step (a) may include vehicle movement signals from vehicle movement sensors506aindicating whether the work vehicle100is moving across a ground surface106, and work implement movement signals from work implement movement sensors506bcorresponding to movement of the work implement114,120of the excavator100relative to the machine frame102.

In the method described above step (b) may further include determining that the excavator100has changed from a transport state to a stationary operating state by determining that the excavator100is not moving across the ground surface106, and by determining that the work implement114,120has moved greater than a threshold value relative to the machine frame102within a predetermined time interval. For example, the controller502may determine whether the boom assembly114has rotated through an angle about axis112of greater than 20 degrees within a time interval of 30 seconds. A lesser angle of at least 5 degrees, or at least 10 degrees or at least 15 degrees could be used.

Another example of how the controller502may detect an operating state is to determine that repetitive cycles of movement of the working implement114,120have occurred while the machine is stationary. Operating states may also be indicated by higher engine speeds and/or known operational patterns of an operator input such as a joystick. Operating states may be determined by observing movement of the bucket120, such as detecting a sequence of bucket movement indicating a bucket boom curl when the boom is down, followed by a dumping operation to an outer location.

Upon determining that the excavator100has changed from a transport state to a stationary operating state, the controller502may generate output signals to adjust the object detection range from the longer range600to the shorter range602. The controller may also be programed such that the change from the longer range600to the shorter range602is delayed until a predetermined time interval or delay has occurred, so as to insure that the excavator100is truly in a stationary mode. For example, the controller may wait until the excavator100has been stationary for at least 10 seconds, or preferably at least 20 seconds, before reducing the object detection range setting. A lesser stationary time of at least 1 second or at least 5 seconds could also be used.

After determining that the excavator100is again moving across the ground surface106, the controller502may automatically return the object detection range to the longer range600.

As previously noted, the vehicle movement sensors506amay include direct movement sensors such as a rotational sensor on the tracks104or a GPS sensor mounted on the vehicle100, or indirect indicators of vehicle movement such as a throttle input, a pedal command sensor, or a valve position sensor detecting the input of a vehicle movement command by the operator of the vehicle.

Determination of vehicle movement from direct movement sensors may be described as detecting an actual change in the work state based at least in part on the work state signals. Determination of vehicle movement from indirect movement sensors may be described as predicting a future change in the work stated based at least in part on the work state signals from the indirect movement sensors.

The controller502may display an image of the working area surrounding the vehicle100,200on the display132,220at the operator station128,216of the work vehicle100,200as seen inFIG.4. The controller502may display a relative location510of the detected object in the image of the working area as also schematically shown inFIG.4.

The controller502may also take into consideration other information in determining whether to place the obstacle detection range setting in a longer or shorter range. The controller may receive GPS data from which it can determine when the vehicle is in a known working area. The controller may consider known obstacles in the work area, which may for example be in the form of a “virtual fence” in which boundaries have been established beyond which the machine or its working implement should not go.

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.