A method of operating a work vehicle according to a maximum allowable swing speed

Abstract

A method of operating a work vehicle is provided. The work vehicle comprises a swing apparatus rotatable about a swing axis, wherein the swing apparatus comprises an arm arrangement comprising a boom and a stick. The method comprises determining a speed profile of maximum allowable swing speed of the swing apparatus rotating about the swing axis by determining a maximum initial swing speed; determining a maximum safety swing speed for stopping the rotation of the swing apparatus within a predetermined maximum angular stopping displacement from a safety time and / or displacement; and determining a deceleration ramp of the maximum allowable swing speed. The deceleration ramp is for reducing the maximum initial swing speed to the maximum safety swing speed by the safety time and / or displacement. The method further comprises, by a control system, limiting a maximum operational swing speed of the swing apparatus to the speed profile.

Description

TECHNICAL FIELD

[0001] The present disclosure relates to a method of operating a work vehicle according to a maximum allowable swing speed, a controller configured to perform such a method and a work vehicle configured to be operated in accordance with such a method.BACKGROUND

[0002] Work vehicles or machines such as excavators or backhoe loaders have various degrees of freedom. One such degree of freedom is swing, which refers to the rotation of the main body relative to its undercarriage, or the rotation of an arm arrangement relative to the main body. Various features affect the swing characteristics, including the swing speed and swing acceleration of the work vehicle. For example, the position of its components, such as the position of an arm arrangement and / or tool, may alter a moment of inertia. This may affect the rate at which the swing speed can be increased or decreased. In addition, a configuration of the work vehicle, such as the type of tool attached, may affect the moment of inertia and therefore the rate at which the swing speed can be increased or decreased.

[0003] It is important that the swing speed can be reduced to zero within a certain distance or time to allow an operator to stop the swing quickly, such as when becoming aware of an obstruction or hazard within a safe distance.

[0004] In addition to this general requirement, European regulation EN 474 requires that a work vehicle, specifically an excavator, must be able to perform a 180-degree swing with a 100% control input and then subsequently stop within a predetermined distance. The regulation previously required that this be accomplished with the most common configuration of the work vehicle. The European regulation EN 474 has been updated to require that a work vehicle must be able to stop within the safe distance in every available configuration.SUMMARY

[0005] An object of the present disclosure may be to provide a method of limiting the maximum operational swing speed of a work vehicle for allowing the work vehicle to reduce its swing speed to zero in a safe distance. A further object is to ensure that such a method operates across the different authorised configurations of the work vehicle. In addition, a further object is to ensure that such a method does not overly reduce the swing speed of the work vehicle. If the swing speed is overly reduced, an operator may notice this during single function and some multi-function operations.

[0006] The present disclosure is generally directed towards limiting the maximum operational swing speed of a swing apparatus of a work vehicle, such as the main body of an excavator, so that it can stop within a safe distance and / or angle after performing a predetermined swing. A control system is configured to limit the swing speed to a speed profile where the speed profile is initially at a high value and then decreases to a safety speed close to the end of the predetermined swing. The safety speed may be a low enough value to ensure the swing apparatus can stop within the safe distance. The speed profile may vary in time, or against angle rotated, measured from the start of a swing.

[0007] The present disclosure provides a method of operating a work vehicle comprising a swing apparatus rotatable about a swing axis, wherein the swing apparatus comprises an arm arrangement comprising a boom and a stick. The method comprises determining a speed profile of maximum allowable swing speed of the swing apparatus rotating about the swing axis by determining a maximum initial swing speed; determining a maximum safety swing speed for stopping the rotation of the swing apparatus within a predetermined maximum angular stopping displacement from a safety time and / or displacement; and determining a deceleration ramp of the maximum allowable swing speed. The deceleration ramp is for reducing the maximum initial swing speed to the maximum safety swing speed by the safety time and / or displacement. The method further comprises, by a control system, limiting a maximum operational swing speed of the swing apparatus to the speed profile.

[0008] There is also provided a controller for controlling a work vehicle comprising a swing apparatus rotatable about a swing axis, wherein the swing apparatus comprises an arm arrangement comprising a boom and a stick. The controller is configured to limit a maximum operational swing speed of the swing apparatus to a speed profile of maximum allowable swing speed of the swing apparatus rotating about the swing axis. The speed profile comprises a maximum initial swing speed; a maximum safety swing speed for stopping the rotation of the swing apparatus within a predetermined maximum angular stopping displacement from a safety time and / or displacement; and a deceleration ramp of the maximum allowable swing speed. The deceleration ramp is for reducing the maximum initial swing speed to the maximum safety swing speed by the safety time and / or displacement.

[0009] There is also provided a work vehicle comprising a swing apparatus rotatable about a swing axis, wherein the swing apparatus comprises an arm arrangement comprising a boom and a stick and a control system comprising the controller described above.

[0010] By way of example only, embodiments according to the present disclosure are now described with reference to, and as shown in, the accompanying drawings.BRIEF DESCRIPTION OF THE DRAWINGS

[0011] FIG. 1 is a side elevation of an embodiment of a system of the present disclosure;

[0012] FIG. 2 is a top elevation of the system of FIG. 1;

[0013] FIG. 3 is a schematic of a control system of the system of FIG. 1;

[0014] FIG. 4A is a graph showing a maximum speed profile varying against angular displacement in accordance with the present disclosure;

[0015] FIG. 4B is a graph showing a maximum speed profile varying in time in accordance with the present disclosure;

[0016] FIG. 5A is a graph showing respective maximum, high inertia configuration, and low inertia configuration speed profiles according to an embodiment of the present disclosure; and

[0017] FIG. 5B is a graph showing respective maximum, high inertia configuration, and low inertia configuration speed profiles according to another embodiment of the present disclosure;DETAILED DESCRIPTION

[0018] 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.

[0019] 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.

[0020] 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.

[0021] 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.

[0022] FIG. 1 illustrates an embodiment of a system 9 comprising a work vehicle 10, in this case an excavator. The work vehicle 10 may be any suitable type of work vehicle 10, including multi-purpose work vehicles, such as excavators, backhoes, loaders, dozers, shovels, fellers, harvesters, material handlers and other such work vehicles. The work vehicle 10 comprises a swing apparatus 11 and may comprise a swing base 13. The swing apparatus 11 comprises an arm arrangement 14. The swing apparatus 11 may comprise a main body 12. The swing base 13 may comprise an undercarriage 32 and / or a platform. The undercarriage 32 may comprise wheels or tracks 20. The main body 12 may comprise a cab 8 for an operator and a power unit (not shown) therein for providing power to the wheels or tracks 20.

[0023] The swing apparatus 11 may be attached to the swing base 13 via a swivel mount 31.

[0024] The swivel mount 31 may allow the swing apparatus 11 to rotate in relation to the swing base 13. The swivel mount 31 may comprise a slip ring or a slewing ring. Rotation of the swing apparatus 11 relative to the swing base 13 may be actuated using a swing actuator 30. The swing actuator 30 may comprise a hydraulic motor or a hydraulic swivel.

[0025] The swing apparatus 11 is rotatable about a swing axis 33. The swing apparatus 11 may be able to rotate by 360 degrees relative to the swing base 13 about the swivel mount 31 and / or swing axis 33. The swing axis 33 may be perpendicular to the swing base 13 and / or may be perpendicular to a horizontal plane or the ground when the work vehicle 10 is on a level surface. The swing axis 33 may be a central axis of the swivel mount 31 and may be the axis of rotation of the swing apparatus 11 relative to the swing base 13 at the swivel mount 31.

[0026] The arm arrangement 14 comprises a boom 16 and a stick 17. The boom 16 and the stick 17 may be pivotally attached to one another. The boom 16 may be pivotally attached to the main body 12 at a first end of the boom 16. The stick 17 may be pivotably attached to the boom 16 at a second end of the boom 16 and a first end of the stick 17. A tool 15 may be connected to the arm arrangement 14. The tool 15 may be pivotably attached to the stick 17 at a second end of the stick 17. The arm arrangement 14 may comprise at least one hydraulic actuator 18, 19, 21 for controlling the orientation thereof. In particular, the arm arrangement 14 may comprise a boom hydraulic actuator 18 for controlling the orientation and movement of the boom 16. The arm arrangement 14 may comprise a stick hydraulic actuator 19 for controlling the orientation and movement of the stick 17. The arm arrangement 14 may comprise a tool hydraulic actuator 21 for controlling the orientation and movement of the tool 15.

[0027] The tool 15 may be of any suitable type. The tool 15 may, for example, be a bucket as illustrated or may be a grapple, 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. The tool 15 may comprise a spray head or the like for providing a water spray during operation of the work vehicle 10, for example for dust suppression. The fluid may be pressurised hydraulic fluid, water or the like.

[0028] The work vehicle 10 may be operable in, configurable in and / or comprise at least one configuration. The configuration may refer to one or more of a swing apparatus 11 measurement; a swing base 13 measurement; a boom 16 measurement; a stick 17 measurement; a main body 12 measurement; a cab 8 measurement; a tool 15 measurement; and / or a type of tool 15. The aforementioned measurements may be a dimension measurement and / or a weight measurement. The dimension measurement may be a length, a width, a depth, an area, and / or a volume. The weight measurement may be a weight or a mass.

[0029] The work vehicle 10 may be operable in, configurable in, and / or comprise a plurality of configurations with different inertias, including a configuration having the greatest moment of inertia. In the greatest inertia configuration, the type of tool 15 may be a tool with a greater mass than other available tools and / or the arm arrangement 14 may comprise components of a greater length, weight and / or mass.

[0030] The work vehicle 10 may be orientable in and / or comprise a component position. The component position may comprise a boom 16 position; a stick 17 position; and / or a tool 15 position. The position may be defined by a component angle. The position may be defined by a component cylinder extension. The component position may comprise an arm arrangement 14 position, or a linkage position. Each configuration of the work vehicle 10 may be capable of having a plurality of different component positions.

[0031] The boom 16 may comprise a boom axis 35. The boom axis 35 may be an axis parallel to the direction along which the boom 16 extends for a majority of its length. The stick 17 may comprise a stick axis 37. The stick axis 37 may be an axis parallel to the direction along which the stick 17 extends for a majority of its length. A boom angle 39 may be the angle between the boom axis 35 and the swing axis 33. A stick angle 41 may be the angle between the boom axis 35 and the stick axis 37. The boom angle 39 and / or stick angle 41 may be used to define the component position. Global angles wherein the various axes are measured relative to the horizontal may be used to define the component position.

[0032] The boom, stick and tool hydraulic actuators 18, 19, 21 may each comprise a hydraulic cylinder and a piston rod. Hydraulic fluid may be supplied to the actuators to displace the rod relative to the cylinder. The boom hydraulic actuator 18 may comprise a boom hydraulic piston rod (not shown). The stick hydraulic actuator 19 may comprise a stick hydraulic piston rod 5. As the stick hydraulic piston rod and / or the stick hydraulic piston rod 5 are extended, the component position may change. A boom hydraulic piston rod extension and / or a stick hydraulic piston rod extension may be used to define the component position.

[0033] FIG. 2 provides an illustration of the work vehicle 10 of FIG. 1 in plan view, in which the swing axis 33 is illustrated as a point. The work vehicle may comprise a reference travel axis 43. The reference travel axis 43 may be substantially horizontal to the ground 33, lie in the same plane as the horizontal, and may pass through and / or be perpendicular to the swing axis 33. The reference travel axis 43 may be parallel to the direction the work vehicle travels when the tracks 20 are actuated simultaneously with the same input. The reference travel axis 43 may be parallel to a direction the work vehicle 10 travels when a forward command is given.

[0034] The work vehicle 10 may comprise a swing apparatus axis 45. The swing apparatus axis 45 may lie in the same plane as the horizontal, and / or may lie in the same plane as the reference travel axis 43. The swing apparatus axis 45 may be parallel to a direction of extension of the arm arrangement 14 (as shown in FIG. 2) and may pass through and / or be perpendicular to the swing axis 33. The swing apparatus axis 45 may be parallel to a direction an operator faces while sitting in the cab 8.

[0035] The work vehicle 10 may comprise a swing angle θ . The swing angle θ may be defined as the angle measured between the reference travel axis 43 and the swing apparatus axis 45. When the swing angle θ is increased or decreased, the swing apparatus 11 may rotate around the swing axis 33 at a swing speed w. The swing apparatus 11 may rotate relative to the swing base 13 at a swing speed w. The swing apparatus 11 may rotate around the swing axis 33 in a swing direction (clockwise or anti clockwise). The swing speed ω may be a swing velocity comprising the swing direction.

[0036] The work vehicle 10 may comprise a work vehicle fluid circuit (not shown) around which fluid may be circulated. The work vehicle 10 may comprise a controller 51 for controlling the work vehicle fluid circuit automatically or based upon inputs received from at least one input device 6 (shown in FIG. 1). The at least one input device 6 may comprise one or more of a joystick, a display 57, a touch screen, a button, or any suitable input device. The least one input device 6 may be used to operate the work vehicle 10. The work vehicle 10 may be operated to change the component position. The work vehicle fluid circuit may be connected to the at least one hydraulic actuator 18, 19, 21.

[0037] Changing the component position may comprise controlling the at least one hydraulic actuator 18, 19, 21 for pivoting of the arm arrangement 14 and the tool 15. The work vehicle 10 may be operated to increase or decrease the swing angle θ. The work vehicle fluid circuit may be connected to the swing actuator 30 and a swing brake 34 for controlling the swing of the swing apparatus 11 relative to the swing base 13.

[0038] The swing speed ω may be controlled and / or affected by the least one input device 6.

[0039] When an input to the least one input device 6 indicates an increase, the swing speed ω may increase. When the input to the input device 6 indicates a decrease, the swing speed ω may decrease. When an input of 100% speed is provided to the at least one input device 6, the swing speed ω may increase towards a maximum operational swing speed of the work vehicle. When an input of 0% speed is provided to the at least one input device, the swing speed ω may decrease towards a zero swing speed ω, or the swing speed ω may remain at zero.

[0040] In order to decrease the swing speed ω, the system 9 may apply the swing brake 34 and / or may stop the application of torque by the swing actuator 30. The system 9 may apply the swing brake 34 to the swivel mount 31 and / or the swing actuator 30. The swing brake 34 may apply a brake torque τb in the opposite direction to the swing direction. The swing brake 34 may cause the swing speed ω to decrease. The swing brake 34 may cause the swing speed ω to decrease to zero.

[0041] For reasons of safety, it may be beneficial that the system 9 is able to reduce the swing speed ω to zero within a predetermined maximum angular stopping displacement θs. In addition, there are regulatory requirements that the system 9 is able to reduce the swing speed ω to zero within the predetermined maximum angular stopping displacement es. The predetermined maximum angular stopping displacement θs may be a 90-degree angular displacement. It may be required that the system 9 is able to reduce the swing speed ω to zero from the maximum operational swing speed within a predetermined angular displacement. It may be required that the system 9 is able to reduce the swing speed ω to zero from the maximum operational swing speed within an angular displacement of 90 degrees. It may be required that the system 9 is able to reduce the swing speed ω to zero after performing a safety angular displacement θsafety. The safety angular displacement θsafety may be 180 degrees. A requirement that the system 9 is able to reduce the swing speed ω to zero after performing a safety angular displacement θsafety ensures that even in the configuration of the greatest inertia, which may only reach the maximum operational swing speed at the end of the safety angular displacement θsafety, must also stop within the predetermined maximum angular stopping displacement θs. It may be required that the system 9 is able to reduce the swing speed ω to zero within the predetermined maximum angular stopping displacement θs regardless of the configuration and / or component position of the work vehicle 10. Instead of the predetermined maximum angular stopping displacement θs, a different metric, such as a predetermined maximum stopping time, may be used.

[0042] The swing apparatus 11 comprises a moment of inertia J. The moment of inertia J is the physical quantity of a body which represents the body's resistance to a change in angular speed. The moment of inertia J affects the ability of the system 9 to reduce the swing speed ω to zero within the predetermined maximum angular stopping displacement θs. A larger moment of inertia J results in a larger angular displacement required to reduce the swing speed ω to zero and results in a lower swing speed being required to so that the swing speed ω can be reduced to zero within the predetermined maximum angular stopping displacement es.

[0043] The moment of inertia J may be linked to the brake torque τb and an angular deceleration experienced during braking by the following formula:τb=J⁢α

[0044] Where α is the angular deceleration and is the rate of change of swing speed ω.

[0045] The moment of inertia J around an axis, may be defined as the sum of the products obtained by multiplying the mass of each particle of matter in a given body by the square of its distance from the axis. The moment of inertia J of the swing apparatus 11 may be higher when a tool 15 with a larger mass is attached to the arm arrangement 14 and may be lower when a tool 15 with a smaller mass is attached to the arm arrangement 14. The moment of inertia J of the swing apparatus 11 may be higher when the component position is such that the arm arrangement 14 extends by a longer distance from the swing axis 33 and may be lower when the component position is such that the arm arrangement 14 extends by a shorter distance from the swing axis 33. The moment of inertia J may constantly change when the work vehicle 10 is in use and is therefore not a known design parameter of the work vehicle 10.

[0046] The system 9 may comprise a control system 50, which may be configured to perform the methods of the present disclosure. As illustrated in FIG. 3, the control system 50 may comprise the controller 51, which may comprise a memory 53, which may store instructions or algorithms in the form of data, and a processing unit 55, which may be configured to perform operations based upon the instructions. The controller 51 may be of any suitable known type and may comprise an engine control unit (ECU) or the like. The memory 53 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 processing unit 55 may comprise any suitable processor capable of executing memory-stored instructions, such as a microprocessor, uniprocessor, a multiprocessor and the like. The controller 51 may further comprise a graphics processing unit for rendering objects for viewing on the display 57 of the control system 50. The controller 51 may also be in communication with least one work vehicle communication module 59 for transferring data with an external computing system 61 via a wired or wireless network 63 (such as Ethernet, fibre optic, satellite communication network, broadband communication network, cellular, Bluetooth). The external computing system 61 may comprise computing systems, processors, servers, memories, databases, control systems and the like.

[0047] As summarised in FIG. 3, the system 9 may comprise at least one system actuator 4. The at least one system actuator 4 may comprise one or more of the boom, stick and tool hydraulic actuators 18, 19, 21, the swing actuator 30 and the swing brake 34.

[0048] The system 9 may comprise at least one sensor 7. The at least one sensor 7 may comprise one or more of a swing angle sensor 71, at least one movement or acceleration sensor 73, at least one component position sensor 75, a boom pressure sensor 77, an inertial measurement unit (IMU), an accelerometer, a gyroscope, a magnetometer, and a pressure sensor. In order to reduce complexity of the work vehicle 10, it may be beneficial to reduce the number of sensors necessary. For example, it may be beneficial for the work vehicle 10 to not include the swing angle sensor 71 if possible.

[0049] The controller 51 may be communicatively connected (via a wired or wireless connection) to the power unit, and any of the at least one system actuator 4 and / or at least one sensor 7 for providing control signals thereto and receiving sensor signals therefrom in order to control the operation of the work vehicle 10. The controller 51 may communicate with the input device 6, for receiving an input and controlling the work vehicle 10. The input device 6 may be in communication with the controller 51 for controlling the actuation of the swing actuator 30 and / or swing brake 34 to adjust the swing speed ω and / or adjust the swing angle θ of the swing apparatus 11. The input device 6 may increase or decrease the swing speed ω of the swing apparatus 11 relative to the swing base 13.

[0050] The controller 51 may receive operating condition data indicative of at least one operating condition of the work vehicle 10 by being communicatively coupled with the at least one sensor 7 and the at least one system actuator 4. The controller 51 may process the received operating condition data to determine further operating condition data and may store the operating condition data on the memory 53. The at least one operating condition and operating condition data may comprise at least one of:

[0051] The swing angle θ of the work vehicle 10, relative to the reference travel axis 43 (as shown in FIG. 2). The control system 50 may comprise a swing angle sensor 71 for determining the swing angle θ of the work vehicle 10;

[0052] The swing speed ω of the work vehicle 10. The control system 50 may comprise at least one movement or acceleration sensor 73 for determining the swing speed ω of the work vehicle 10;

[0053] The component position of the work vehicle 10. The control system 50 may comprise at least one component position sensor 75 for determining the component position of the work vehicle 10. The at least one component position sensor 75 may be mounted to the swing apparatus 11. The at least one component position sensor 75 may comprise at least one inertial measurement unit (IMU);

[0054] The boom position; stick position; and / or tool position of the work vehicle 10.

[0055] The control system 50 may comprise at least one component position sensor 75 attached to the boom 16; stick 17 and / or tool 15 for determining the boom 16; stick 17; and / or tool 15 position of the work vehicle 10. The at least one component position sensor 75 may comprise at least one inertial measurement unit (IMU) attached to the boom 16; stick 17 and / or tool 15;

[0056] A component movement and / or acceleration of the work vehicle 10. The control system 50 may comprise at least one movement or acceleration sensor 73 for determining the component movement and / or acceleration of the work vehicle 10. The at least one movement or acceleration sensor 73 may be mounted to the swing apparatus 11. The at least one movement or acceleration sensor 73 may be at least one accelerometer;

[0057] A boom movement and / or acceleration; stick movement and / or acceleration; and / or tool movement and / or acceleration. The control system 50 may comprise at least one movement or acceleration sensor 73 attached to the boom 16; stick 17 and / or tool 15 for determining the boom 16; stick 17; and / or tool 15 movement and / or acceleration. The at least one movement or acceleration sensor 73 may comprise at least one accelerometer attached to the boom 16; stick 17 and / or tool 15;

[0058] The boom and / or stick angle of the work vehicle 10. The control system 50 may comprise the component position sensor 75, such as the IMU for determining the boom and / or stick angle of the work vehicle 10;

[0059] The boom and / or stick hydraulic piston rod extension of the work vehicle 10. The control system 50 may comprise the component position sensor 75, such as the IMU for determining the boom and / or stick hydraulic piston rod extension of the work vehicle 10;

[0060] A boom head end pressure of the work vehicle 10. The boom head end pressure may be indicative of the mass of the arm arrangement 14. The boom head end pressure may be indicative of the moment of inertia J of the swing apparatus 11.

[0061] The control system 50 may comprise a boom pressure sensor 77, which may be within the boom hydraulic cylinder 18, for determining the boom head end pressure of the work vehicle 10;

[0062] The configuration of the work vehicle 10. The configuration of the work vehicle 10 may be input by an operator via the at least one input device 6; stored on the memory 53; and / or detected automatically using work vehicle sensors;

[0063] The brake torque τb of the swing brake 34 of the work vehicle 10. The brake torque τb may be input by an operator via at least one input device 6, stored on the memory 53 and / or estimated based upon a change in the component movement and / or acceleration upon application of the swing brake 34. The brake torque τb applied at any time may be based upon the input to the at least one input device 6. A 0% input to the at least one input device 6 may result in a maximum brake torque τb,max being applied by the swing brake 34;

[0064] An actuation torque ta of the swing actuator 30 of the work vehicle 10. The actuation torque τa may be input by an operator via at least one input device 6, stored on the memory 53 and / or estimated based upon a change in the component movement and / or acceleration upon application of the swing actuator 30. The actuation torque τa may be based upon the input to the at least one input device 6;

[0065] The maximum operational swing speed of the work vehicle. The maximum operational swing speed of the work vehicle may be determined according to the methods of this disclosure;

[0066] A maximum allowable swing speed ωmax of the work vehicle. The maximum allowable swing speed ωmax of the work vehicle may be determined according to the methods of this disclosure;

[0067] A maximum initial swing speed ωmax,init of the work vehicle 10. The maximum initial swing speed ωmax,init may be input by an operator via at least one input device 6 and / or stored on the memory 53. The maximum initial swing speed ωmax,init may be set by safety considerations and / or vehicle limits;

[0068] A maximum safety swing speed ωmax, safety of the work vehicle 10. The maximum safety swing speed ωmax, safety may be input by an operator via at least one input device 6 and / or stored on the memory 53. The maximum safety swing speed ωmax,safety may be determined according to the methods of this disclosure;

[0069] A speed profile 101 of the work vehicle 10. The speed profile 101 may be input by an operator via at least one input device 6 and / or stored on the memory 53. The speed profile 101 may be determined according to the methods of this disclosure;

[0070] The predetermined maximum angular stopping displacement θs. The predetermined maximum angular stopping displacement θs may be input by an operator via at least one input device 6 and / or stored on the memory 53. The predetermined maximum angular stopping displacement θs may be set by a regulatory and / or a safety requirement;

[0071] The safety angular displacement θsafety. The safety angular displacement θsafety may be input by an operator via at least one input device 6 and / or stored on the memory 53. The safety angular displacement θsafety may be set by a regulatory and / or a safety requirement;

[0072] A ramp down start displacement θramp. The ramp down start displacement θramp may be input by an operator via at least one input device 6 and / or stored on the memory 53. The ramp down start displacement θramp may be determined according to the methods of this disclosure;

[0073] A time t measured from the start of performing an angular displacement. The time t may be measured by the control system;

[0074] A safety time tsafety. The safety time tsafety may be input by an operator via at least one input device 6 and / or stored on the memory 53. The safety time tsafety may be determined according to the methods of this disclosure; and

[0075] A ramp down start time tramp. The ramp down start time tramp may be input by an operator via at least one input device 6 and / or stored on the memory 53. The ramp down start time tramp may be determined according to the methods of this disclosure.

[0076] The operating condition data collected by the control system 50 may be transferred to the external computing system 61, which may perform the method of the present disclosure. Thus, the control system 50 may be considered in the present disclosure to comprise the external computing system 61, which may have instructions stored thereon for performing the methods disclosed herein in a similar manner to the controller 51.

[0077] A method of operating the work vehicle 10 comprises determining the speed profile 101 of maximum allowable swing speed ωmax of the swing apparatus 11 rotating about the swing axis 33 and, by the control system 50, limiting the maximum operational swing speed of the swing apparatus 11 to the speed profile 101.

[0078] Generally, the speed profile 101 indicates the maximum allowable swing speed wmax Of the swing apparatus 11 over a certain displacement or time and the swing apparatus 11 operates at or below this maximum allowable swing speed ωmax.

[0079] As shown in FIGS. 4A and 4B, the speed profile 101 comprises, and is determined by determining, the maximum initial swing speed ωmax,init; the maximum safety swing speed ωmax,safety; and a deceleration ramp 103 of the maximum allowable swing speed ωmax. The maximum safety swing speed ωmax,safety is for stopping the rotation of the swing apparatus 11 within the predetermined maximum angular stopping displacement θs from the safety angular displacement θsafety and / or the safety time tsafety. The deceleration ramp 103 is for reducing the maximum initial swing speed ωmax,init to the maximum safety swing speed ωmax,safety by the safety angular displacement 0θsafety and / or the safety time tsafety.

[0080] The maximum safety swing speed ωmax,safety may be determined in a variety of ways. If the work vehicle 11 is configurable in a plurality of configurations including a greatest inertia configuration, the maximum safety swing speed ωmax,safety may be based upon a rate of deceleration of the swing apparatus 11 in the greatest inertia configuration, and the predetermined maximum angular stopping displacement θs. The maximum safety swing speed ωmax,safety may be calculated as the swing speed ω from which the swing apparatus 11 will slow to zero within the predetermined maximum angular stopping displacement θs given the rate of deceleration of the swing apparatus 11 in the greatest inertia configuration. The rate of deceleration of the swing apparatus 11 in the greatest inertia configuration may be determined by inputting data regarding the greatest inertia configuration into a simulation, computational model and / or digital twin of the work vehicle 10 and then calculating and / or modelling the rate of deceleration of the swing apparatus 11 of the simulation, computational model and / or digital twin. The rate of deceleration of the swing apparatus 11 in the greatest inertia configuration may be calculated based upon a determined moment of inertia of the greatest inertia configuration. The rate of deceleration may be determined by experimentation and / or empirical methods.

[0081] If the work vehicle 11 comprises at least one component position sensor 75 mounted to the swing apparatus 11, the maximum safety swing speed ωmax,safety may be based upon work vehicle component position data from the at least one component position sensor 75. The maximum safety swing speed ωmax,safety may be determined as the swing speed ω from which the swing apparatus 11 will slow to zero within the predetermined maximum angular stopping displacement θs given the work vehicle component position data. The maximum safety swing speed ωmax,safety may be determined by comparing the component position data and the predetermined maximum angular stopping displacement θs to a look up table or map to find the appropriate maximum safety swing speed ωmax,safety. The look up table or map may be prepared via experimentation and / or empirical methods to find the appropriate maximum safety swing speed ωmax,safety for a given component position and the predetermined maximum angular stopping displacement θs.

[0082] If the work vehicle 11 comprises a boom 16; a boom actuator 18; and at least one boom head pressure sensor 77 mounted to the boom actuator 18, the maximum safety swing speed ωmax,safety may be based upon boom head pressure data from the at least one boom head pressure sensor 77. The maximum safety swing speed ωmax,safety may be determined as the swing speed ω from which the swing apparatus 11 will slow to zero within the predetermined maximum angular stopping displacement θs given the boom head pressure data. The maximum safety swing speed ωmax,safety may be determined by comparing the boom head pressure data and the predetermined maximum angular stopping displacement θs to a look up table or map to find the appropriate maximum safety swing speed ωmax,safety. The look up table or map may be prepared via experimentation and / or empirical methods to find the appropriate maximum safety swing speed ωmax,safety for a given boom head pressure and the predetermined maximum angular stopping displacement θs.

[0083] The speed profile 101 may comprise a speed profile varying against angular displacement θ and / or time t as described below.

[0084] As shown in FIG. 4A, the speed profile 101 may comprise a maximum allowable swing speed ωmax varying against angular displacement θ measured from the start of performing an angular displacement 00. The angular displacement θ may be determined by the swing angle sensor 71. The speed profile 101 may comprise the safety displacement θsafety and may comprise the ramp down start displacement θramp. The deceleration ramp 103 may reduce the maximum allowable swing speed ωmax from the maximum initial swing speed ωmax,init to the maximum safety swing speed ωmax,safety between the ramp down start displacement θramp and the safety displacement θsafety.

[0085] The ramp down start displacement θramp may be based upon maximum initial swing speed ωmax,init, the maximum safety swing speed ωmax,safety, a rate of deceleration of the swing apparatus 11; and the safety displacement θsafety. The ramp down start displacement θramp may be determined as the greatest possible angular displacement θ from which the swing speed can be reduced from the maximum initial swing speed ωmax,init to the maximum safety swing speed ωmax,safety before the safety displacement θsafety, given the rate of deceleration of the swing apparatus 11. The ramp down start displacement θramp may be determined as the greatest possible angular displacement θ from which the swing speed ω can be reduced from the maximum initial swing speed ωmax,init to the maximum safety swing speed ωmax,safety before the safety displacement θsafety, regardless of the vehicle configuration used.

[0086] The ramp down start displacement θramp may be based upon the maximum rate of deceleration of the swing apparatus 11 in the greatest inertia configuration. The ramp down start displacement θramp may be based upon a rate of deceleration of the swing apparatus 11 which is less than the maximum rate of deceleration so that a smoother deceleration is experienced by the user. The ramp down start displacement θramp may be determined by experimentation and / or empirical methods across different configurations of the work vehicle 11.

[0087] As shown in FIG. 4B, the speed profile 101 may comprise a maximum allowable swing speed ωmax varying in time t measured from the start of performing an angular displacement t0. The speed profile 101 may comprise the safety time tsafety and may comprise the ramp down start time tramp. The deceleration ramp 103 of the maximum allowable swing speed ωmax may reduce the maximum initial swing speed ωmax,init to the maximum safety swing speed ωmax,safety between the ramp down start time tramp and the safety time tsafety. The deceleration ramp 103 of the maximum allowable swing speed ωmax may reduce the maximum initial swing speed ωmax,init to the maximum safety swing speed ωmax,safety between the ramp down start time tramp and the safety time tsafety.

[0088] The safety time tsafety may be determined based upon a rate of acceleration of the swing apparatus 11. The safety time tsafety may be based upon the safety displacement 0safety. The safety time tsafety may be determined as the time at which the swing apparatus 11 will reach the safety displacement θsafety. The safety time tsafety may be based upon the rate of acceleration of the swing apparatus 11 in the greatest inertia configuration. The safety time tsafety may be determined as the time at which the swing apparatus 11 will reach the safety displacement θsafety given the rate of acceleration of the swing apparatus 11 in the greatest inertia configuration. This can ensure that speed profile 101 will be at the maximum safety swing speed ωmax,safety at the safety displacement θsafety when the greatest inertia configuration is used (which is important because the maximum safety swing speed ωmax,safety may be necessary for the greatest inertia configuration to stop within the predetermined maximum angular stopping displacement θs). If the safety time tsafety is based upon the rate of acceleration of the swing apparatus 11 in the greatest inertia configuration, then the speed profile 101 may be above the maximum safety swing speed ωmax,safety at the safety displacement θsafety when a configuration other than the greatest inertia configuration is used (this may be non-problematic because the swing apparatus 11 may be able to stop within the predetermined maximum angular stopping displacement θs from a swing speed above the maximum safety swing speed ωmax,safety in configurations other than the greatest inertia configuration). The safety time tsafety may be determined as the time at which the swing apparatus 11 will reach the safety displacement θsafety given the rate of acceleration of the swing apparatus 11 in a configuration other than the greatest inertia configuration. The safety time tsafety may be determined such that the speed profile 101 will be at the maximum safety swing speed ωmax,safety by the safety displacement θsafety regardless of its configuration.

[0089] The safety time tsafety may be determined by experimentation and / or empirical methods across different configurations of the work vehicle 11.

[0090] The ramp down start time tramp may be based upon maximum initial swing speed ωmax,init, the maximum safety swing speed ωmax,safety, a rate of deceleration of the swing apparatus 11; and the safety time tsafety. The ramp down start time tramp may be determined as the latest time t from which the swing speed ω can be reduced from the maximum initial swing speed ωmax,init to the maximum safety swing speed ωmax,safety before the safety time tsafety, given the rate of deceleration of the swing apparatus 11. The ramp down start time tramp may be determined as the latest possible time t from which the swing speed ω can be reduced from the maximum initial swing speed ωmax,init to the maximum safety swing speed ωmax,safety before the safety displacement tsafety, regardless of the vehicle configuration used. The ramp down start time tramp may be based upon the maximum rate of deceleration of the swing apparatus 11 in the greatest inertia configuration. The ramp down start time tramp may be based upon a rate of deceleration of the swing apparatus 11 which is less than the maximum rate of deceleration so that a smoother deceleration is experienced by the user. The ramp down start time tramp may be determined by experimentation and / or empirical methods across different configurations of the work vehicle 11.

[0091] As shown in FIGS. 4A and 4B, the deceleration ramp 103 may be a linear deceleration ramp 103. The speed profile 101 may decrease linearly between the ramp down start time tramp and / or displacement θramp and the safety time tsafety and / or displacement θsafety. The linear decrease may have a gradient based on the rate of deceleration of the swing apparatus 11 in the greatest inertia configuration. Alternatively, the linear decrease may have a gradient shallower that the rate of deceleration of the swing apparatus 11 in the greatest inertia configuration so that a smoother deceleration is experienced by the user. The gradient may be determined by experimentation and / or empirical methods across different configurations of the work vehicle 11.

[0092] FIG. 5A shows a generalised maximum speed profile 101 against displacement θ and / or time t including the linear deceleration ramp 103, a high inertia speed profile 105 of the swing speed ω of the swing apparatus 11 in a high inertia configuration and a low inertia speed profile 107 of the swing speed ω of the swing apparatus 11 in a low inertia configuration. The high inertia speed profile 105 and the low inertia speed profile 107 may be the respective speed profiles experienced when an input of 100% speed is provided to the at least one input device 6. The high and low inertia speed profiles 105, 107 both show an initial acceleration (represented by a positive gradient) until they reach the maximum speed profile 101. The low inertia speed profile 107 shows a steeper initial gradient representing a greater angular acceleration than the high inertia speed profile 105 because it is a lower inertia configuration and so can accomplish a higher angular acceleration. The low inertia speed profile 107 may reach the maximum speed profile 101 before the deceleration ramp 103. The high inertia speed profile 105 may reach the maximum speed profile 101 during the deceleration ramp 103. After reaching the maximum speed profile 101, both the high and low inertia speed profiles 105, 107 follow the maximum speed profile 101. As the configuration of the work vehicle 10 is changed, different speed profiles may be experienced, of which the high and low inertia speed profiles 105, 107 are two examples.

[0093] The deceleration ramp 103 may be a non-linear deceleration ramp 109. FIG. 5B shows a generalised maximum speed profile 101 against displacement θ and / or time t, the high inertia speed profile 105 and the low inertia speed profile 107 when the non-linear deceleration ramp 109 is used. The speed profile 101 may decrease at a faster rate nearer the ramp down start time tramp and / or displacement θramp and at a slower rate nearer the safety time tsafety and / or displacement θsafety. The non-linear deceleration ramp 109 can allow configurations able to reach the maximum initial swing speed ωmax,init prior to the ramp down start time tramp and / or displacement θramp to decelerate at a quicker rate than rate of deceleration of the swing apparatus 11 in the greatest inertia configuration (which is beneficial because configurations able to reach the maximum initial swing speed ωmax,init prior to the ramp down start time tramp and / or displacement θramp will have a lower inertia and therefore may be able to decelerate faster). The non-linear deceleration ramp 109 can allow the ramp down start time tramp and / or displacement θramp to be later and so the maximum initial swing speed ωmax,init is possible for a longer time t and / or angular displacement θ.

[0094] Limiting the maximum operational swing speed of the swing apparatus 11 to the speed profile 101 by the control system 50 may include the control system 50 measuring the time t and / or angular displacement θ from starting to perform an angular displacement and selecting a corresponding maximum swing speed ωmax from the speed profile 101 corresponding to the present time t and / or angular displacement θ. The control system 50 may then set the maximum operational swing speed as the corresponding maximum swing speed ωmax. As the time t and / or angular displacement θ changes and / or progresses, the control system 50 may select a new corresponding maximum swing speed ωmax from the speed profile 101 to the new present time t and / or angular displacement θ. The control system 50 may update the maximum operational swing speed by setting the maximum operational swing speed as the new corresponding maximum swing speed ωmax. The control system may constantly update the maximum operational swing speed according to the speed profile 101 as the time t and / or angular displacement θ changes and / or progresses.

[0095] When the swing speed ω is reduced to zero, and / or a new angular displacement is started, the control system 50 may start measuring the time t and / or angular displacement θ again from zero. Starting to measure the time t and / or angular displacement θ again from zero every time a new angular displacement is started ensures the speed is only limited to the maximum safety swing speed ωmax,safety towards the end of performing the safety angular displacement 74safety and not at other times.

[0096] The control system 50 may determine the speed profile 101. The speed profile may be determined external of the control system 50 and uploaded to the memory 53 of the control system.

[0097] The method may further comprise the control system 50 rotating the swing apparatus 11 about the swing axis 33 at a swing speed ω equal to or less than the maximum operational swing speed. The method may further comprise the control system 50 overriding a user command to rotate the swing apparatus 11 around the swing axis 33 at a swing speed ω greater than the maximum operational swing speed. Overriding the user command may comprise receiving a user input to perform a rotation at a swing speed ω greater than the maximum operational swing speed and outputting a command to the swing actuator 30 to perform a rotation at a swing speed ω equal to or less than the maximum operational swing speed.INDUSTRIAL APPLICABILITY

[0098] The method may thus limit the maximum operational swing speed of the work vehicle 10 to allow the work vehicle 10 to reduce its swing speed ω to zero within the predetermined maximum angular stopping displacement 05 after performing the safety angular displacement θsafety. By limiting the maximum operational swing speed of the swing apparatus 11 to the speed profile 101, wherein the speed profile 101 comprises the deceleration ramp 103 to the maximum safety swing speed ωmax,safety by the safety angular displacement θsafety, the work vehicle 10 will always be at a safe swing speed by the end of the safety angular displacement θsafety.

[0099] The method may operate effectively across the different authorised configurations of the work vehicle. If the maximum safety swing speed ωmax,safety is based on the greatest inertia configuration, then the work vehicle 10 will always be able to stop from the safety angular displacement θsafety regardless of configuration. If the maximum safety swing speed ωmax,safety is based upon work vehicle component position data, or boom head pressure data, then the work vehicle will be at a safe swing speed by the end of the safety angular displacement θsafety for the present configuration and / or component position. In addition, performance will not be overly limited because of the potential for other configurations and / or component positions, since the maximum safety swing speed ωmax,safety is adjusted for the present configuration and / or component position. The method may also not overly affect the swing performance of the work vehicle 10 because the swing speed ω may not be limited to the maximum safety swing speed ωmax,safety for many angular displacements θ. Many angular displacements θ performed by an operator in normal use will be of an angle less than the safety angular displacement θsafety and so the swing performance of the work vehicle 10 will be unaffected by the limitations imposed by this method for much of normal use. It is only when the safety angular displacement θsafety is approached and the speed needs to be limited for safety reasons that the limitations imposed by this method are effected.

[0100] If the speed profile 101 comprises a maximum allowable swing speed ωmax varying against angular displacement θ, then the speed profile may be accurately calibrated with the safety angular displacement θsafety. Therefore, the method may fulfil the safety requirements without additional safety margins necessary if the exact angular displacement θ is not known.

[0101] If the speed profile 101 comprises a maximum allowable swing speed ωmax varying in time t, then this method can be implemented without use of a swing sensor 71. Producing lower cost models of the work vehicle 10 may involve reducing the number of sensors used and so the method functioning without use of a swing sensor 71 may improve efficiency.

[0102] If the deceleration ramp 103 is the non-linear deceleration ramp 109 as shown in FIG. 5B, then the ramp down start time tramp and / or displacement θramp can be later and so the maximum initial swing speed ωmax,init is possible for a longer time t or angular displacement θ as explained above.

Claims

1. A method of operating a work vehicle comprising a swing apparatus rotatable about a swing axis, wherein the swing apparatus comprises an arm arrangement comprising a boom and a stick, the method comprising:determining a speed profile of maximum allowable swing speed of the swing apparatus rotating about the swing axis by:determining a maximum initial swing speed;determining a maximum safety swing speed for stopping the rotation of the swing apparatus within a predetermined maximum angular stopping displacement from a safety time and / or displacement; anddetermining a deceleration ramp of the maximum allowable swing speed for reducing the maximum initial swing speed to the maximum safety swing speed by the safety time and / or displacement; andby a control system, limiting a maximum operational swing speed of the swing apparatus to the speed profile.

2. The method of claim 1, wherein the deceleration ramp of the maximum allowable swing speed reduces the maximum initial swing speed to the maximum safety swing speed between a ramp down start time and / or displacement and the safety time and / or displacement respectively.

3. The method of claim 2 wherein the ramp down start time and / or displacement is based upon:the maximum initial swing speed;the maximum safety swing speed;a rate of deceleration of the swing apparatus; andthe safety time and / or displacement.

4. The method of claim 2, wherein the speed profile comprises a maximum allowable swing speed varying in time measured from the start of performing an angular displacement.

5. The method of claim 4, wherein the safety time is determined based upon a rate of acceleration of the swing apparatus.

6. The method of claim 2, wherein the work vehicle comprises a swing angle sensor and the speed profile comprises a maximum allowable swing speed varying against angular displacement measured from the start of performing an angular displacement.

7. The method of claim 3, wherein the work vehicle is configurable in a plurality of different configurations of differing inertias and:the ramp down start time and / or displacement is further based upon the rate of deceleration of the swing apparatus in the configuration having the greatest inertia; and / orthe maximum safety swing speed is based upon a rate of deceleration of the swing apparatus in the configuration having the greatest inertia and the predetermined maximum angular stopping displacement.

8. The method of claim 1, wherein the speed profile decreases linearly between the ramp down start time and / or displacement and the safety time and / or displacement.

9. The method of claim 1, wherein the speed profile decreases at a faster rate nearer the ramp down start time and / or displacement and at a slower rate nearer the safety time and / or displacement.

10. The method of claim 1, wherein the work vehicle comprises at least one component position sensor mounted to the swing apparatus and wherein the maximum safety swing speed is based upon work vehicle component position data from the at least one component position sensor.

11. The method of claim 1, wherein the work vehicle further comprises:a boom actuator for controlling the boom; andat least one boom head pressure sensor mounted to the boom actuator, wherein the maximum safety swing speed is based upon boom head pressure data from the at least one boom head pressure sensor.

12. The method of claim 1, wherein the method further comprises, by the control system:rotating the swing apparatus about the swing axis at a swing speed equal to or less than the maximum operational swing speed; and / oroverriding a user command to rotate the swing apparatus around the swing axis at a swing speed greater than the maximum operational swing speed.

13. A controller for controlling a work vehicle comprising a swing apparatus rotatable about a swing axis, wherein the swing apparatus comprises an arm arrangement comprising a boom and a stick, the controller being configured to limit a maximum operational swing speed of the swing apparatus to a speed profile of maximum allowable swing speed of the swing apparatus rotating about the swing axis, wherein the speed profile comprises:a maximum initial swing speed;a maximum safety swing speed for stopping the rotation of the swing apparatus within a predetermined maximum angular stopping displacement from a safety time and / or displacement; anda deceleration ramp of the maximum allowable swing speed for reducing the maximum initial swing speed to the maximum safety swing speed by the safety time and / or displacement.

14. A work vehicle comprising:a swing apparatus rotatable about a swing axis, wherein the swing apparatus comprises an arm arrangement comprising a boom and a stick; anda control system comprising the controller of claim 13.

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