Work vehicle control system and method for avoiding collisions with overhead objects

Abstract

A work vehicle control system includes at least one object proximity sensor 42 for determining an overhead object 44 configuration. At least one moveable member sensor 41 for determining an arm arrang

Description

TECHNICAL FIELD This disclosure is directed towards a control system for and method of controlling a work vehicle to avoid collisions with overhead objects. BACKGROUND Excavators and other work vehicles often have to operate near objects with which there is a risk of collision. As a result, various collision avoidance systems have been proposed and implemented to avoid or reduce the risk of collisions. US2023150358A1, for example, discloses a collision avoidance system for a work vehicle. A controller receives a signal indicative of the presence of an obstacle in a surrounding area of the work vehicle and determines a position of the obstacle relative to the work vehicle. The controller generates a first control signal to prevent a movement of the work vehicle, halt the movement of the work vehicle, or reduce a velocity of the work vehicle based on the determination of the position of the obstacle. The controller generates a second control signal for displaying an updated display view that provides a visual indication of the presence of the obstacle in the surrounding area of the work vehicle. Furthermore, US2024011244A1 discloses a collision avoidance system including determining a boundary zone and providing a notification and / or control command to prevent a collision with another object based on a relationship of an object to the boundary zone. However, improved systems are desirable, particularly for overhead object collision avoidance. Whilst on ground object collision avoidance needs the work vehicles to be effectively controlled in traveling, turning, and swinging in two-dimensional directions, overhead collision (such as with bridges or utility lines) requires significant additional accurate detection and motion control in the third dimension of elevation. SUMMARY An object of the present disclosure is to provide an improved collision avoidance system for work vehicles operating close to overhead objects. A problem with implementing existing collision avoidance systems for overhead objects is that the determination of elevation requires significant additional computational power on the work vehicle engine control module (“ECM”). As a result, utilising such existing collision avoidance systems for overhead objects may not be possible on work vehicles with an ECM with too low computational power. This can drive up the costs of retrofit, requiring a new ECM, and the development of new machines with sufficiently capable ECMs. The present disclosure is therefore directed at providing a simpler, lower cost overhead object collision avoidance system. Instead of analysing the entire configuration (e.g. shape, size, location, velocity, angular rotation etc) of the work machine and overhead object, in the present disclosure more limited profiles of the work machine and overhead object are determined and tracked. The profiles can, for example, just consist of a few points or surfaces of the work machine and overhead object, such as the points and surfaces thereof that are closest to one another. The potential for a collision can then be assessed based upon such profiles, avoiding full three dimensional tracking and the associated computational requirements. Furthermore, when assessing the response of the work machine after a potential collision is detected, different modes can be used in which the assessment of the motion response is limited, thereby further reducing computational requirements. The present disclosure therefore provides a control system for operating a work vehicle in proximity to an overhead object, a work vehicle and a method in accordance with the claims. The control system is for controlling a work vehicle, the control system being configured, by at least one controller, to perform a series of steps as set out below. The work vehicle comprises an arm arrangement and the control system. The control system comprises at least one overhead object sensor configured to generate overhead object data indicative of the overhead object configuration and at least one moveable member sensor configured to generate arm arrangement data indicative of the arm arrangement configuration. The controller is in communication with the at least one overhead object sensor and at least one moveable member sensor. The controller determines, based on overhead object data received from the at least one overhead object sensor, current and predicted overhead object profiles indicative of the current and future configurations of the overhead object. The controller also determines, based on arm arrangement data received from the at least one moveable member sensor, current and predicted arm arrangement profiles indicative of the current and future configurations of the arm arrangement. The controller operates the work vehicle in a potential collision control mode upon identifying, based on the predicted overhead object and arm arrangement profiles, a potential future collision between the overhead object and arm arrangement. By utilising the profiles of the object and arm arrangement, rather than requiring full, continuous, three-dimensional motion analysis of the object and arm arrangement, the system of the present disclosure has a significantly lower computational requirement. For example, the profiles may comprise position(s) of at least one point, line and / or surface of the object and arm arrangement, rather than all points, lines or surfaces thereof. The controller may operate the operator alert system to issue an alert to an operator of the work vehicle in the event of a possible collision. The controller may be configured to implement safe or productive modes in order to automatically control or restrain control of the work vehicle, based upon the pre-selection of the safe or productive modes. In each of the safe and productive modes, calculations and control steps are restricted in order to reduce the computational power required in implementing such modes. In the potential collision control mode the controller may be configured to operate the work vehicle in a safe mode by determining at least one safe motion control of the work vehicle and / or arm arrangement and subsequently automatically operating, or enabling by manual operation of, the arm arrangement in accordance with the at least one safe motion control. In the safe mode the controller is configured to determine a predicted safe motion control arm arrangement profile indicative of the configuration of the arm arrangement when the at least one safe motion control is implemented. The controller may identify, based on the predicted safe motion control arm arrangement profile and predicted overhead object profile, that a collision between the object and arm arrangement will be avoided when the at least one safe motion control is implemented. The controller may then operate the work vehicle in accordance with the at least one safe motion control. In the potential collision control mode the controller may be configured to operate the work vehicle in a productive mode by determining the at least one safe motion control and at least one productive motion control of the work vehicle and / or arm arrangement and subsequently automatically operating, or enabling by manual operation of, the arm arrangement in accordance with the at least one productive motion control or at least one safe motion control. In the productive mode the controller may be configured to determine a predicted productive motion control arm arrangement profile indicative of the configuration of the arm arrangement when the at least one productive motion control is implemented. The controller may identify, based on the predicted productive motion control arm arrangement profile and predicted overhead object profile, that a collision between the object and arm arrangement will be avoided when the at least one productive motion control is implemented. The controller may operate the work vehicle in accordance with the at least one productive motion control. The controller may store a motion control map of all possible safe and / or productive motion controls and, in the safe mode and / or productive mode, the controller is configured to determine a risk of collision of the predicted safe and / or productive motion control arm arrangement profiles for fewer safe and / or product motion controls than those stored on the motion control map. The arm arrangement may comprise a boom and a stick. The at least one safe motion control may comprise lowering, stopping movement of and / or maintaining stationary the boom and / or stick. The at least one productive motion control may comprise raising the boom and / or stick. The work vehicle may comprise a driving system for moving the work vehicle across a terrain. The at least one safe motion control may comprise operating the driving system to move the work vehicle away from the object, stop movement of the work vehicle and / or maintaining the position of the work vehicle. The at least one productive motion control may comprise operating the driving system to move the work vehicle towards the object. The work vehicle may comprise a main body rotatably mounted to an undercarriage by a swing system, the arm arrangement being mounted to the main body. The at least one safe motion control may comprise operating the swing system to rotate the arm arrangement away from the object, stop movement of the main body relative to the undercarriage and / or maintaining the position of the main body relative to the undercarriage. The at least one productive motion control may comprise operating the swing system to move the arm arrangement towards the object. The present disclosure further provides a non-transitory computer-readable storage medium including program code which when executed by at least one processor causes operations comprising the method. The control system may comprise or be embodied as a machine electronic control module for controlling the work vehicle, the machine electronic control module comprising the controller. The present disclosure is directed towards any suitable type of work vehicle required to operate near overhead objects. The work vehicle comprises an arm arrangement, which may comprise a tool, configurable into different orientations by the control system and / or an operator and the method and control system is directed to avoiding contact between the arm arrangement and an overhead object. The work vehicle may further comprise, additionally or alternatively, an undercarriage to which a main body is rotatably mounted, such as via a swing system. The arm arrangement may comprise a boom mounted to the main body, a stick mounted to the boom and a tool mounted to the stick. The work vehicle may therefore comprise an excavator, backhoe, shovel, dragline, a drill and / or material handler or the like. The work vehicle may alternatively comprise a dozer, shovel, wheeled tractor scraper, motor grader or a hauling machine, such as a dump truck, off- highway truck, mining truck, on-highway truck or lorry / truck or articulated hauler or the like. The tool may be of any suitable type and may, for example, be a grapple, bucket, tiltable bucket, tilt rotator, hammer, handling arm, multi-processor, pulveriser, saw, shears, blower, grinder, tiller, trencher, winch, auger, broom, cutter, planer, delimber, felling head, mulcher, or rake. In the present disclosure, the term “overhead object” refers to an object extending above the terrain on which the work vehicle is located and with which the arm arrangement may collide. The overhead object may be located at least about 1m, about 2m or about 5m above the terrain. In preferred embodiments, the overhead object is located above the undercarriage and / or above the main body of the work vehicle. The overhead object may be located above the midway point of the height of the work vehicle, when from the terrain to the uppermost point of the main body (particularly the cab thereof). The overhead object may be located above the highest reach of the boom. The overhead object may be a power line, utilities line, bridge, building or the like. BRIEF DESCRIPTION OF THE DRAWINGS By way of example only, embodiments of the present disclosure are now described with reference to, and as shown in, the accompanying drawings, in which: Figure 1 is an illustration of a work vehicle in proximity to an overhead object in accordance with the present disclosure; Figure 2 is a schematic of a control system of the work vehicle of Figure 1; and Figure 3 is a schematic flowchart illustrating the operation of a controller of the control system of Figure 2 and a method in accordance with the present disclosure. DETAILED DESCRIPTION The ensuing description provides preferred exemplary embodiment(s) only, and is not intended to limit the scope, applicability, or configuration of the invention. Rather, the ensuing description of the preferred exemplary embodiment(s) will provide those skilled in the art with an enabling description for implementing a preferred exemplary embodiment of the invention, it being understood that various changes may be made in the function and arrangement of elements, including combinations of features from different embodiments, without departing from the scope of the invention. Specific details are given in the following description to provide a thorough understanding of the embodiments. However, it will be understood by one of ordinary skill in the art that embodiments may be practised without these specific details. For example, well-known circuits, processes, algorithms, structures, and techniques may be shown without unnecessary detail in order to avoid obscuring the embodiments. Also, it is noted that the embodiments may be described as a process which is depicted as a flowchart, a flow diagram, a data flow diagram, a structure diagram, or a block diagram. Although a flowchart may describe the operations as a sequential process, many of the operations can be performed in parallel or concurrently. In addition, the order of the operations may be re-arranged. A process is terminated when its operations are completed but could have additional steps not included in the figure. A process may correspond to a method, a function, a procedure, a subroutine, a subprogram, etc. When a process corresponds to a function, its termination corresponds to a return of the function to the calling function or the main function. Moreover, as disclosed herein, the term "storage medium" may represent one or more devices for storing data, including read only memory (ROM), random access memory (RAM), magnetic RAM, core memory, magnetic disk storage mediums, optical storage mediums, flash memory devices and / or other machine readable mediums for storing information. The term "computer-readable medium" includes but is not limited to portable or fixed storage devices, optical storage devices, wireless channels, and various other mediums capable of storing, containing, or carrying instruction(s) and / or data. Furthermore, embodiments may be implemented by hardware, software, firmware, middleware, microcode, hardware description languages, or any combination thereof. When implemented in software, firmware, middleware or microcode, the program code or code segments to perform the necessary tasks may be stored in a machine readable medium such as storage medium. A processor(s) may perform the necessary tasks. A code segment may represent a procedure, a function, a subprogram, a program, a routine, a subroutine, a module, a software package, a class, or any combination of instructions, data structures, or program statements. A code segment may be coupled to another code segment or a hardware circuit by passing and / or receiving information, data, arguments, parameters, or memory contents. Information, arguments, parameters, data, etc. may be passed, forwarded, or transmitted via any suitable means including memory sharing, message passing, token passing, network transmission, etc. It is to be understood that the following disclosure provides many different embodiments, or examples, for implementing different features of various embodiments. Specific examples of components and arrangements are described below to simplify the present disclosure. These are, of course, merely examples and are not intended to be limiting. In addition, the present disclosure may repeat reference numerals and / or letters in the various examples. This repetition is for the purpose of simplicity and clarity and does not in itself dictate a relationship between the various embodiments and / or configurations discussed. Moreover, the formation of a first feature over or on a second feature in the description that follows may include embodiments in which the first and second features are formed in direct contact and may also include embodiments in which additional features may be formed interposing the first and second features, such that the first and second features may not be in direct contact. Figure 1 illustrates an embodiment of a work vehicle 10, in this case an excavator for excavating material from the ground, terrain and / or worksite, according to the present disclosure. The work vehicle 10 may comprise a main body 12 having a cab 8 for an operator and an arm arrangement 14 attached to the main body 12. The work vehicle 10 may comprise an undercarriage 30 to which the main body 12 is rotatably mounted, such as via a swing system 31. The work vehicle 10 comprises a driving system 46, comprising for example an internal combustion engine and / or electrical power system with at least one battery providing power to at least one motor, for driving at least one wheel and / or track 13 for driving the work vehicle 10 along a terrain 33. The driving system 46 may comprise a system brake for braking movement of the work vehicle 10. The arm arrangement 14 may comprise a boom 16, a stick 17 and a linkage arrangement 20 pivotally attached to one another. The arm arrangement 14 may comprise a tool 15 connected to the stick 17 and linkage arrangement 20 via a coupling arrangement 11. The arm arrangement 14 may comprise hydraulic actuators 18, 19, 21 for controlling the orientation and movement of the boom 16, stick 17 and linkage arrangement 20 and thereby the orientation and movement of the coupling arrangement 11 and tool 15. The undercarriage 30 may comprise a chassis 32 to which the at least one wheel and / or track 13 may be mounted. The swing system 31 may be mounted to a top of the chassis 32 and the at least one wheel and / or track 13 may be mounted to opposing sides of the chassis 32. The swing system 31 may comprise at least one swing motor for rotating the main body 12 relative to the undercarriage 30. The work vehicle 10 may comprise a hydraulic system 5 for operating the arm arrangement 14 and / or at least one tool 15 and around which fluid may be circulated. The hydraulic system 5 may comprise the first, second and third hydraulic actuators 18, 19, 21 for controlling the pivoting of the arm arrangement 14 and the tool 15. The work vehicle 10 may comprise a control system 40, illustrated further in Figure 2, for controlling the hydraulic system 5 automatically or based on inputs received from the user interface 6 and / or automatically. The user interface 6 may comprise an input device controllable by an operator in the main body 12, such as a joystick or at least one button, and may comprise at least one display for displaying information to a user, such as a screen or lighting. The control system 40 may be configured to perform the methods of the present disclosure. The control system 40 comprises a controller 49 configured to perform operations based on instructions. The controller 49 may comprise a memory 47, which may store instructions or algorithms in the form of data. The controller 49 may be of any suitable known type and may comprise an engine control unit (ECU), machine electronic control module or the like. The memory 47 may comprise any suitable computer-accessible or non-transitory storage medium for storing computer program instructions, such as RAM, SDRAM, DDR SDRAM, RDRAM, SRAM, ROM, magnetic media, optical media and the like. The controller 49 may comprise any suitable processor 48 capable of executing memory-stored instructions, such as a microprocessor, uniprocessor, a multiprocessor and the like. The controller 49 may further comprise a graphics processing unit for rendering objects for viewing on the display of the user interface 6, and / or a separate display of the control system 40. The controller 49 may also be in communication with an external computing system via a wired or wireless network (such as Ethernet, fibre optic, satellite communication network, broadband communication network, cellular, Bluetooth). The external computing system may comprise computing systems, processors, servers, memories, databases, control systems and the like. Although the control system 40 is described herein as being part of the work vehicle 10, it will be appreciated that the control system 40 may be entirely or partially located on the external computing system such that the control steps and method disclosed herein are partially or entirely implemented on the external computing system. The controller 49 may be communicatively connected (via a wired or wireless connection) to the driving system 46 and hydraulic system 5 for providing control signals thereto and receiving sensor signals therefrom in order to control the operation of the work vehicle 10. The controller 49 may arranged to control the hydraulic actuators 18, 19, 21 of the work vehicle 10, driving system 46, system brake and / or the swing system 31. The controller 49 may therefore be able to control the swing, movement across terrain 33 and arm arrangement 14 orientation of the work vehicle 10. The controller 49 may communicate with the user interface 6, for receiving an input and controlling the work vehicle 10 and for displaying information to the operator. The control system 40 further comprises at least one moveable member sensor 41, 60, 61 configured to generate arm arrangement data indicative of the configuration of the arm arrangement 14. The at least one moveable member sensor 41, 60, 61 may comprise at least one arm arrangement sensor 41 capable of determining the orientation of the arm arrangement 14 relative to the rest of the work vehicle 10. For example, the at least one arm arrangement sensor 41 may comprise an inertial measurement unit (IMU) and may be mounted on the boom 16, stick 17 and tool 15. The at least one arm arrangement sensor 41 may comprise an IMU, gyroscopic device, camera or the like. Alternatively, the at least one arm arrangement sensor 41 may be in communication with and / or form the user interface 6, with the inputs from the operator being tracked such that the orientation of the arm arrangement 14 relative to the rest of the work vehicle 10 can be determined. Furthermore, the at least one moveable member sensor 41, 60, 61 may comprise a swing angle sensor 60 for determining the location of the main body 12 relative to the undercarriage - IQ- 30 and may comprise at least one driving system sensor 61 for determining the movement and location of the work vehicle 10 relative to the terrain 33. The at least one driving system sensor 61 may comprise one or more sensors for determining and tracking the operation of the driving system 46 and may comprise a vehicle navigation system, such as GPS or the like. The arm arrangement data may be indicative of the configuration of the arm arrangement 14 relative to the terrain 33. In particular, the at least one driving system sensor 61 may determine the location of the work vehicle 10 (particularly the undercarriage 30) relative to the terrain 33, the swing angle sensor 60 may determine the location of the main body 12 relative to the undercarriage 30 and the at least one arm arrangement sensor 41 may determine the orientation of the arm arrangement 14 relative to the main body 12. The arm arrangement data may comprise the identification and / or tracking of the arm arrangement 14. The arm arrangement data may comprise a time series sequence of distance and / or location of the arm arrangement 14 relative to the rest of the work vehicle 10, main body 12, undercarriage 30 and / or terrain 33. The arm arrangement data may comprise the trajectory of the arm arrangement 14. The work vehicle 10 also comprises at least one object proximity sensor 42. The at least one object proximity sensor 42 is configured to generate overhead object data indicative of a detection of an overhead object 44 in proximity to the work vehicle 10. The at least one object proximity sensor 42 may comprise radar; a radar sensor; lidar; a lidar sensor; an ultrasonic sensor; a camera and / or a stereo camera. The object proximity sensors 42 may comprise a selection of different object proximity sensor 42, for example, at least one camera and at least one lidar, and / or at least one camera and at least one radar. The object proximity sensors 42 may comprise any number of any of the above sensors 42 in combination, or other suitable sensors for generating object proximity data 43. The at least one object proximity sensor 42 may a detect an overhead object 44 within about 1 m, about 3 m, about 5 m, about 10 m, or about 20 m of the work vehicle 10. The at least one object proximity sensor 42 may comprise two, three, four, five, seven, ten or more object proximity sensors 42. The object proximity sensors 42 may be arranged at different locations around the work vehicle 10, may be arranged symmetrically around the work vehicle 10 and / or may be arranged to give a broad sensor coverage around the work vehicle 10. The at least one object proximity sensor 42 may be mounted to the undercarriage and / or the main body 36. The overhead object data may comprise radar data, lidar data, ultrasound data, image data, and / or stereo image data. The overhead object data may comprise the distance and / or location of the overhead object 44 relative to the at least one object proximity sensor 42 and / or to the work vehicle 10. The overhead object data may comprise data derived from a mixture of sources, and / or may comprise data derived from a combination of the radar data, lidar data, ultrasound data, image data, and / or stereo image data. This may enhance the accuracy and / or reliability of the overhead object data. The overhead object data may comprise the identification and / or tracking of the overhead object 44. When the overhead object data comprises image data, image recognition may be used to identify and track a specific overhead object 44. When the overhead object data comprises radar data, lidar data, or ultrasound data, a signal size may be used to identify and track a specific overhead object 44. The overhead object data may comprise a time series sequence of distance and / or location of the specific overhead object 44 relative to the at least one object proximity sensor 42 and / or to the work vehicle 10. The overhead object data may comprise the trajectory of the overhead object 44. The object proximity data and arm arrangement data may be stored on the memory 57 of the controller 49. The controller 49 may access and use the object proximity data and arm arrangement data from the memory 57 and / or from the sensors 41,42, 60, 61 according to the methods of this disclosure. The controller 49 comprises (such as by being stored on the memory 53) and / or is configured to operate in accordance with a collision avoidance protocol 69. The collision avoidance protocol 69 adapts operation of the work vehicle 10 to account for an overhead object 44. The collision avoidance protocol 69 may prevent a collision of the work vehicle 10 with the overhead object 44, and / or may aid the operator in avoiding a collision of the work vehicle 10 with the overhead object 44. The collision avoidance protocol 69 may be activated based on the object proximity data 43 from the at least one object proximity sensor 42. The operation of the control system 40 and method of the present disclosure are now described with reference to Figure 3. At step 100, the controller 49 receives initial settings from an operator, either via the user interface 6 or from the external computing system. The initial settings may comprise whether to operate the work vehicle 10 in a safe mode or a productive mode, as described further hereinbelow. Step 101 illustrates the starting point To of the feedback loop shown in Figure 3. Generally, the left loop of the flowchart (Tn+i=Tn+Step 1) illustrates the sequence where there is no potential for a collision. The right loop of the flowchart (Tn+i=Tn+Step 2) illustrates the sequence when there is the potential for a collision. The controller 49 regularly performs the left loop according to a time monitor, such as every 0.5 s. If a potential collision is identified, the controller 49 performs the right loop according to a time monitor, such as every 0.5 s, until no potential collision is identified. The controller 49 then returns to the left loop. At step 102, the controller 49 communicates with and receives the object proximity data and arm arrangement data, for example as signals, from the at least one object proximity sensor 42 and at least one moveable member sensor 41,60, 61. For example, the arm arrangement data comprises the current position and velocity of the arm arrangement sensors 31 on the arm arrangement 14. For example, the object proximity data comprises an image of an area surrounding the work vehicle 10, potentially included the overhead object 42, as well as the location and velocity of the overhead object 42, which may be determined from multiple sequential images. At step 103, the controller 49 determines, based on the arm arrangement data, current and predicted arm arrangement profiles indicative of the current and future configurations of the arm arrangement 14. The current arm arrangement profile is the existing profile from the arm arrangement data, whilst the predicted arm arrangement profile indicates the predicted movement of the arm arrangement 14 in an upcoming time period. The predicted arm arrangement profile may be determined by the controller based upon the current arm arrangement profile and velocity data from the arm arrangement data. The velocity data may be determined from, for example, a sequence of signals from the at least one moveable member sensor 41, 60, 61 (e.g. from IMUs on the boom 16, stick 17 and tool 15). The arm arrangement profiles comprise position(s) of at least one point, line and / or surface of the arm arrangement 14, and preferably those in closest proximity to the overhead object 44. In other words, the arm arrangement profiles may comprise the closest or uppermost point(s), line(s) and / or surface(s) of the arm arrangement 14 to the overhead object 44. The arm arrangement profile may not contain information about the point(s), line(s) and / or surface(s) of the lower parts of the arm arrangement 14, main body 12 or undercarriage 30. The arm arrangement profiles may comprise a plurality of points, such as points A, B and C of the tool 15, stick 17 and boom 16 illustrated in Figure 1. In particular, the arm arrangement profile may be formed from one point A on the tool 15, such as being located at the point on the tool 15 furthest from the main body 12 when the arm arrangement 14 is fully extended, one point B on the stick 17, such as the point on the stick 17 furthest from the tool 15, and one point C on the boom 16. The at least one moveable member sensor 41,60, 61 need not be located at such points A, B, C, since the controller 49 may store the relative locations of the points A, B, C to the at least one moveable member sensor 41, 60, 61 so as to be able to determine the locations of the points A, B, C, such as relative to the terrain 33 or vehicle 10. The arm arrangement profile may comprise: fewer than 5, 10, 25, 50 or 100 points; fewer than 5, 10 or 25 lines; and / or fewer than 3, 5, 10 or 20 surfaces. Effectively the arm arrangement profile may contain significantly less data on the layout and configuration of the arm arrangement 14 than that contained in the arm arrangement data sent to the controller 49. At step 104, the controller 49 determines, based on the overhead object data, current and predicted overhead object profiles indicative of the current and future configurations of the overhead object 44. The configuration may comprise the shape, position and velocity of the object 44. The current overhead object profile is the existing profile from the overhead object data, whilst the predicted overhead object profile indicates the predicted movement of the overhead object 44 in an upcoming time period. The predicted overhead object profile may be determined by the controller based upon the current overhead object profile and velocity data from the overhead object data. The velocity data may be determined from, for example, a sequence of images of the overhead object 44. The predicted overhead object profile is the same as the current overhead object profile if the overhead object 44 is stationary. The overhead object profiles comprise position(s) of at least one point, line and / or surface of the overhead object 44, and preferably those in closest proximity to the arm arrangement 14. In other words, the overhead object profiles may comprise the closest or lowermost point(s), line(s) and / or surface(s) of the overhead object 44 to the arm arrangement 14. The overhead object profile may not contain information about the point(s), line(s) and / or surface(s) on the opposing side of the overhead object 44 to the arm arrangement 14, such as on the opposing 50% or 25% of the outer surface of the overhead object 44 to the arm arrangement 14. The overhead object profile may comprise a plurality of points, such as points X, Y and Z of the power line illustrated in Figure 1. The overhead object profile may comprise: fewer than 10, 25, 50 or 100 points; fewer than 5, 10 or 25 lines; and / or fewer than 3, 5, 10 or 20 surfaces. Effectively the overhead object profile contains significantly less data on the layout and configuration of the overhead object 44 than that contained in the overhead object data sent to the controller 49. By only defining the overhead object and arm arrangement profiles by such points, lines or surfaces, only the predicted movement of those points, lines or surfaces needs to be calculated by the controller 49 in order to determine the predicted overhead object and arm arrangement profiles. This significantly reduces the computational requirements of determining the current and predicted configurations of the overhead object 44 and arm arrangement 14, as well as reduces the computational requirements of assessing their movement relative to one another in order to determine the likelihood of a collision. At step 105, the controller 49 determines, based on the predicted overhead object and arm arrangement profiles, whether there is a potential future collision between the overhead object 44 and arm arrangement 14. In particular, the controller 49 may assess vectors of the predicted overhead object and arm arrangement profiles and determine that they will collide with one another if they continue along their current trajectory. The potential future collision may be a predicted future collision with 100% risk of collision. Alternatively, if there are variables in the trajectory of the predicted overhead object and arm arrangement profiles, the controller 49 may determine the potential future collision where the risk of collision is above a certain threshold of certainty, such as by being 25% or 50% likely. Step 106 is implemented if the controller 49 determines that there is no potential future collision between the overhead object 44 and arm arrangement 14. In particular, no change is made to the operation of the work vehicle 10 and no restraints are placed on its movement. Instead, the controller 49 cycles back to performing the left loop of Figure 3, returning to step 102, thereby regularly checking at discrete time intervals whether there is a potential collision. At step 107, a potential collision control mode is implemented when the controller 49 identifies a potential future collision between the overhead object 44 and arm arrangement 14. The control system 40 may comprise an operator alert system, which may be embodied in the user interface 6, and at step 108 the controller 49 may operate the operator alert system or user interface 6 to issue an alert to an operator of the work vehicle 10, thereby ensuring that they are aware of a potential collision. In the potential collision control mode, the controller 49 may implement a safe mode or a productive mode based upon the settings received in step 100. The safe mode and productive mode define the possible motion controls available to the controller 49 (i.e. available motions of the vehicle 10 the controller 49 can operate in) when in the potential collision control mode. In the safe mode only the safest motion controls are allowed, whilst in the productive mode some additional motion controls are available, allowing the work vehicle 10 to still be operated productively. This means that at step 100, settings are entered so as to specify whether the safe mode or productive mode should be implemented, which an operator or site operator, for example, can specify depending upon the circumstances in which the work vehicle 10 is operated. For example, if the operator of the work vehicle 10 is relatively inexperienced, or there are many live power lines on the worksite, a site operator may specify the safe mode. However, if the operator is very experienced and the work requires operation close to overhead objects 44, such as bridges, the productive mode is specified. The controller 49 stores a motion control map of all possible safe and / or productive motion controls and, in the safe mode and / or productive mode, different motion controls are available. The following table illustrates an exemplary motion control map, in which A, B, C, D indicate the travel A of the work vehicle 10 across the terrain 33, the swing B of the main body 12 about the undercarriage 30, the movement of the boom C and the movement of the stick D. The - indicates movements away from the overhead object 44, the 0 indicates no movement and the + indicates movements towards the overhead object 44. Travel A Swing B Boom C Stick D A- B- C- D- A0 B0 CO DO A + B + c + D + The safe mode comprises motion controls A -, B -, C -, D -, A 0, B 0, C 0 and D 0. Therefore, the safe mode comprises at least one safe motion control comprising lowering and / or maintaining stationary the boom 16 and / or stick 17; operating the driving system 60 to move the work vehicle 10 away from the object 44 and / or maintaining the position of the work vehicle 10; and / or operating the swing system 31 to rotate the arm arrangement 14 away from the object 44 and / or maintaining the position of the main body 12 relative to the undercarriage 30. The productive mode comprises motion controls A -, B -, C -, D -, A 0, B 0, C 0, D 0, A +, B +, C + and D +. Therefore, the productive mode comprises the safe motion controls as discussed above, as well as: raising the boom 16 and / or stick 17; operating the driving system 60 to move the work vehicle 10 towards the object 44; and / or operating the swing system 31 to move the arm arrangement 14 towards the object 44. At step 109, in the safe mode, the controller 49 may determine all of the motion controls A -, B -, C -, D -, A 0, B 0, C 0 and D 0 available in the safe mode. Alternatively, at step 110, in the productive mode, the controller 49 may determine all of the motion controls A -, B -, C -, D -, A 0, B 0, C 0, D 0, A +, B +, C + and D + available in the productive mode. Furthermore, in steps 109 and 110, the controller 49 also determines all potential combined motion controls, i.e. A, B, C, D, AB, AB, AC, AD, BC, BD, CD, ABC, ABD, ACD, BCD, ABCD. In the safe mode all combinations with - and 0 are determined, whilst in the productive mode all combinations with -, 0 and + are determined. Effectively, a list of possible motion controls is generated, based upon which the subsequent analysis is performed, with the lists differing between the safe and productive modes. The list for the exemplary motion control map above would comprise 15 motion controls for the safe mode and 65 motions controls for the productive mode. This preselection of the available motion controls is subsequently used to determine the scope of the steps 111 to 116, in which the controller 49 determines the motions of the work vehicle 10 that can be implemented to avoid the collision and selects the appropriate motion. Thus, the method comprises, generally across steps 111 to 116, in the potential collision control mode the controller 49 operates the work vehicle 10 in the safe or productive modes by determining at least one safe and / or productive motion control of the work vehicle 10 and / or arm arrangement 14 and subsequently automatically operates, or enables by manual operation of, the arm arrangement 14 in accordance with the at least one safe and / or productive motion control. It will be appreciated that the at least one safe and / or productive motion control may comprise additional motion controls to those set out in the motion control map exemplified above. In particular, the motion control map may comprise a plurality of each of the - and + motions for each of the machine movements A, B, C, D indicating different accelerations and / or velocities. For example, there may be three A- motions indicating slow, medium and fast acceleration of the vehicle away from the overhead object 44. In step 111, the controller 49 is configured to determine a predicted safe or productive motion control arm arrangement profile indicative of the configuration of the arm arrangement 14 when the at least one safe or productive motion control is implemented, depending upon whether the safe or productive mode is being implemented. Therefore, the predicted arm arrangement profiles are determined for all possible motion controls in the list, according to whether the safe or productive mode is being implemented, as determined in steps 109 or 110. In step 112, the predicted overhead object profile may be recalculated in a similar manner to step 104. At step 113a, 113b, the controller 49 is configured to identify, based on the predicted safe or productive motion control arm arrangement profile and predicted overhead object profile, that a collision between the object 44 and arm arrangement 14 will be avoided when the at least one safe or productive motion control is implemented. The controller 49 may, in a similar manner to step 105, determine, based on the predicted overhead object and safe or productive arm arrangement profiles, whether there is a potential future collision between the overhead object 44 and arm arrangement 14 for each of the predicted overhead object and safe or productive arm arrangement profiles. In particular, the controller 49 may assess vectors of the predicted overhead object and safe or productive arm arrangement profiles and determine the risk of collision if the arm arrangement 14 and overhead object 44 continue along their current trajectory. In a particularly beneficial arrangement, the controller 49 may determine the risk of collision of predicted safe and / or productive motion control arm arrangement profiles for fewer safe and / or product motion controls than those stored on the motion control map. In other words, in step 113a, 113b, the controller 49 does not determine the risk of collision for every predicted safe and / or productive motion control arm arrangement profile as determined in step 111. This can be achieved by making assumptions of the risk of collision based upon prior determinations. For example, if the predicted arm arrangement profile for A will effectively avoid a collision, the controller 49 does not check predicted arm arrangement profile AB, AC, AD, ABC etc. because they all should avoid a collision. For example, if predicted arm arrangement profile A-B+C0D0 avoids a collision, the controller 49 does not check predicted arm arrangement profile A-B0C0D0, A-B-C0D0, A-B-C-DO because they should also avoid a collision. Alternatively, for example, if predicted arm arrangement profile A-B0C0D0 will not avoid the collision, the controller 49 does not check predicted arm arrangement profile A-combined with any other riskier control because they will also not avoid the collision. The method of the present disclosure further anticipates multiple overhead objects 44 being detected, by, at steps 113a, 113b, 113n determining the motion controls that can avoid the collision for each overhead object 44 detected. The controller 49 may therefore have determined at least one predicted safe and / or productive motion control arm arrangement profile that avoids a collision and in step 114 the controller 49 may summarise all of the safe and / or productive motion controls available to avoid a collision, depending on whether the safe or productive mode is in force. At step 115, the controller 49 may select the most suitable safe or productive motion control for implementing by the work vehicle 10 to avoid the collision, or may determine a range of safe or productive motion controls to avoid the collision. The controller 49 may select the most suitable motion control based upon a predetermined job priority, which may be received from an operator or administrator from the external computing system or via the user interface 6 at step 100. The predetermined job priority may comprise a prioritised list of machine motion controls (e.g. ABCD) and the controller 49 may determine the most suitable safe or production motion control as that involving movement of the lowest priority on the predetermined job priority list. In an example, there are two movement solutions to avoid the collision identified through the computation process: either A- (stop traveling) or B- (lowering boom). If the predetermined job priority defined by an operator or administrator is ABCD, such as being based on the job site requirements and / or work vehicle requirements, then motion control B- will be selected and implemented at step 115. If C- is a third movement solution, then motion control C- will be selected at step 115, being lower priority than the solutions involvement movements A and B. In addition, a safety margin may be set at step 100, and this may determine the level of collision risk acceptable, with the safe or productive motion control being selected at step 115 accordingly. At step 116, the controller 49 may then operate the work vehicle in accordance with the at least one safe or productive motion control to avoid the collision. The controller 49 may automatically operate the work vehicle 10 in accordance with the selected motion control. Alternatively, the controller 49 may restrain manual control of the work vehicle 10 to only the selected safe or productive motion control, or range thereof, determined in step 115. The controller 49 then returns to step 102 and continues to monitor for overhead objects 44 and the risk of collision. INDUSTRIAL APPLICABILITY The controller 49 continues to operate in accordance with the right loop (102, 103, 104, 105, 107, 109, 110, 111, 112, 113, 114, 115, 116, 102 etc) until there is no more risk of collision between the overhead object(s) and the arm arrangement 14. If there is no risk of collision, the controller 49 continues to operate in accordance with left loop (102, 103, 104, 105, 106, 102 etc) until a risk of collision is determined. As will be appreciated, computational requirements are reduced in numerous ways. Limiting determination of the risk of collision to only the profiles avoids having to compute the trajectory of all parts of the overhead object 44 and work vehicle 10. Limiting the motion controls assessed for risk of collision in the safe mode ensures that unnecessary motion controls are not analysed. By preventing analysing the risk of collision for every possible motion control / predicted arm arrangement profile, by making assumptions on the risk of collision for associated motion controls / predicted arm arrangement profiles, the number of determinations of risk of collision between the motion controls / predicted arm arrangement profiles and overhead object profile can be significantly reduced.

Claims

1. A control system for operating a work vehicle in proximity to an overhead object, the work vehicle comprising an arm arrangement, wherein the control system comprises:at least one object proximity sensor configured to generate overhead object data indicative of the overhead object configuration;at least one moveable member sensor configured to generate arm arrangement data indicative of the arm arrangement configuration; anda controller in communication with the at least one overhead object sensor and at least one moveable member sensor, the controller being configured to:determine, based on overhead object data received from the at least one object proximity sensor, current and predicted overhead object profiles indicative of the current and future configurations of the overhead object;determine, based on arm arrangement data received from the at least one moveable member sensor, current and predicted arm arrangement profiles indicative of the current and future configurations of the arm arrangement; andoperate the work vehicle in a potential collision control mode upon identifying, based on the predicted overhead object and arm arrangement profiles, a potential future collision between the overhead object and arm arrangement.

2. The control system of claim 1 wherein the current and predicted overhead object profiles comprise current and predicted position(s) of at least one point, line and / or surface of the overhead object in closest proximity to the arm arrangement.

3. The control system of claim 1 or claim 2 wherein the current and predicted arm arrangement profiles comprise current and predicted position(s) of at least one outermost point, line and / or surface of the arm arrangement.

4. The control system of any preceding claim wherein in the control system comprises an operator alert system and in the potential collision control mode the controller operates the operator alert system to issue an alert to an operator of the work vehicle.

5. The control system of any preceding claim wherein in the potential collision control mode the controller is configured to operate the work vehicle in a safe mode by determining at least one safe motion control of the work vehicle and / or arm arrangement and subsequently automatically operating, or enabling by manual operation of, the arm arrangement in accordance with the at least one safe motion control.

6. The control system of claim 5 wherein in the safe mode the controller is configured to: determine a predicted safe motion control arm arrangement profile indicative of the configuration of the arm arrangement when the at least one safe motion control is implemented;identify, based on the predicted safe motion control arm arrangement profile and predicted overhead object profile, that a collision between the object and arm arrangement will be avoided when the at least one safe motion control is implemented; andoperate the work vehicle in accordance with the at least one safe motion control.

7. The control system of claim 5 or claim 6 wherein in the potential collision control mode the controller is configured to operate the work vehicle in a productive mode by determining and at least one productive motion control of the work vehicle and / or arm arrangement and subsequently automatically operating, or enabling by manual operation of, the arm arrangement in accordance with the at least one productive motion control.

8. The control system of claim 7 wherein in the productive mode the controller is configured to:determine a predicted productive motion control arm arrangement profile indicative of the configuration of the arm arrangement when the at least one productive motion control is implemented;identify, based on the predicted productive motion control arm arrangement profile and predicted overhead object profile, that a collision between the object and arm arrangement will be avoided when the at least one productive motion control is implemented; andoperate the work vehicle in accordance with the at least one productive motion control.

9. The control system of any one of claims 5 to 8 wherein the controller stores a motion control map of all possible safe and / or productive motion controls and, in the safe mode and / or productive mode, the controller is configured to determine a risk of collision of the predicted safe and / or productive motion control arm arrangement profiles for fewer safe and / or product motion controls than those stored on the motion control map.

10. The control system of any one of claims 5 to 9 wherein the arm arrangement comprises a boom and a stick, further wherein:the at least one safe motion control comprises lowering, stopping movement of and / or maintaining stationary the boom and / or stick; and / orthe at least one productive motion control comprises raising the boom and / or stick.

11. The control system of any one of claims 5 to 10 wherein the work vehicle comprises a driving system for moving the work vehicle across a terrain, further wherein:the at least one safe motion control comprises operating the driving system to move the work vehicle away from the object, stop movement of the work vehicle and / or maintaining the position of the work vehicle; and / orthe at least one productive motion control comprises operating the driving system to move the work vehicle towards the object.

12. The control system of any one of claims 5 to 11 wherein the work vehicle comprises a main body rotatably mounted to an undercarriage by a swing system, the arm arrangement being mounted to the main body, further wherein:the at least one safe motion control comprises operating the swing system to rotate the arm arrangement away from the object, stop movement of the main body relative to the undercarriage and / or maintaining the position of the main body relative to the undercarriage; and / orthe at least one productive motion control comprises operating the swing system to move the arm arrangement towards the object.

13. A work vehicle comprising the control system of any preceding claim.

14. A method of operating a work vehicle in proximity to an overhead object, the work vehicle comprising an arm arrangement and a control system comprising:at least one object proximity sensor configured to generate overhead object data indicative of the overhead object configuration;at least one moveable member sensor configured to generate arm arrangement data indicative of the arm arrangement configuration; anda controller in communication with the at least one overhead object sensor and at least one moveable member sensor,wherein the method comprises, by the controller:determining, based on overhead object data received from the at least one object proximity sensor, current and predicted overhead object profiles indicative of the current and future configurations of the overhead object;determining, based on arm arrangement data received from the at least one moveable member sensor, current and predicted arm arrangement profiles indicative of the current and future configurations of the arm arrangement; andoperating the work vehicle in a potential collision control mode upon5 identifying, based on the predicted overhead object and arm arrangement profiles, a potential future collision between the overhead object and arm arrangement.

15. A non-transitory computer-readable storage medium including program code which when executed by at least one processor causes operations comprising the method of 10 claim 14.

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