EP4724318A1

EP4724318A1 - Assisted recovery mode

Info

Publication number: EP4724318A1
Application number: EP24731543.5A
Authority: EP
Inventors: James Coleman; Aaron Ward; Rowena FURBY; Benjamin Gibbs
Original assignee: Jaguar Land Rover Ltd
Current assignee: Jaguar Land Rover Ltd
Priority date: 2023-06-12
Filing date: 2024-06-05
Publication date: 2026-04-15
Also published as: WO2024256231A1; AU2024304009A1; CN121358644A

Abstract

Aspects of the present invention relate to a control system (100) for controlling a recovery mode of a vehicle (200) for recovery of an object connected to a hitch point (210A-B) of the vehicle (200), the control system (100) comprising one or more processors (120) collectively configured to: receive suspension data (160) from a suspension system (225) of the vehicle (200), the suspension data (160) being indicative of a vertical load on one or more wheels (280A-D) of the vehicle (200); receive gradient data (162) indicative of a gradient of the vehicle (200); determine, in dependence on the suspension data (160) and gradient data (162), a weight distribution of the vehicle (200); and determine, in dependence on the determined weight distribution, a distribution of torque to be applied to the wheels (280A-D) of the vehicle (200) so as to match the weight distribution between the one or more wheels (280A-D); and output, in dependence on the determined distribution of torque, a first control signal (170) to a torque delivery system of the vehicle (200) to redistribute torque applied to the wheels (280A-D) of the vehicle (200) so as to match the weight distribution between the one or more wheels (280A-D). Aspects of the invention also related to a system incorporating a control system (100) and torque delivery system (220) of the vehicle (200), a vehicle (200) incorporating a control system (100), and a method (300) of controlling a recovery mode of a vehicle (200).

Description

ASSISTED RECOVERY MODE

TECHNICAL FIELD

The present disclosure relates to a vehicle control system and control method for controlling an assisted recovery mode of a vehicle. Aspects of the invention relate to a control system, a system, a vehicle and a method.

BACKGROUND

It is known to use a vehicle to provide recovery assistance to an object such as another vehicle that has broken down or is stuck in a stationary position, for example, due to a slippery surface such as mud or sand, or due to an obstruction on the ground preventing the object from moving. To provide recovery assistance, the vehicle will usually be connected to the recovery vehicle via a hitch point and a tow rope. The vehicle will then put into drive to pull the object to another location, either to get further assistance or to a position where it is able to move. However, factors such as the characteristics of the terrain that the vehicle is on and the weight of the object can make it difficult for the vehicle to maintain traction throughout the recovery process, which can hamper the success of the recovery.

It is an aim of the present invention to address one or more of the disadvantages associated with the prior art.

SUMMARY OF THE INVENTION

Aspects and embodiments of the invention provide a control system, a system, a vehicle, a method, and computer readable instructions as claimed in the appended claims.

This disclosure provides a technique for improving the assisted recovery of a vehicle. The technique determines a weight distribution of the vehicle and determines a redistribution of torque so as to match the weight distribution between the wheels of the vehicle.

According to an aspect of the present invention there is provided a control system for controlling a recovery mode of a vehicle for recovery of an object connected to a hitch point of the vehicle. The control system comprises one or more processors collectively configured to receive suspension data from a suspension system of the vehicle, the suspension data being indicative of a vertical load on one or more wheels of the vehicle and receive gradient data indicative of a gradient of the vehicle. The one or more processors are also configured to determine, in dependence on the suspension data and gradient data, a weight distribution of the vehicle; and determine, in dependence on the determined weight distribution, a distribution of torque to be applied to the wheels of the vehicle so as to match the weight distribution between the one or more wheels. The one or more processors are also configured to output, in dependence on the determined distribution of torque, a first control signal to a torque delivery system of the vehicle to redistribute torque applied to the wheels of the vehicle so as to match the weight distribution between the one or more wheels.

In this way, when an object to be recovered is attached to a hitch point of the vehicle, such that the vehicle performing the recovery has an uneven distribution of weight, the torque delivery system is controlled so as to match the torque applied to each wheel to the corresponding load on each wheel. This maximises the longitudinal force delivered to the wheels experiencing the most load and ensures that the maximum amount of longitudinal force is not delivered to the wheels where there is less vertical load to overcome, which could otherwise cause those wheels to spin since there is not enough available traction between the wheels and the ground.

The control system comprises one or more controllers collectively comprising at least one electronic processor having an electrical input for receiving an input signal; and at least one memory device electrically coupled to the at least one electronic processor and having instructions stored therein; and wherein the at least one electronic processor is configured to access the at least one memory device and execute the instructions thereon so as to: receive suspension data from a suspension system of the vehicle, the suspension data being indicative of a vertical load on one or more wheels of the vehicle; receive gradient data indicative of a gradient of the vehicle; determine, in dependence on the suspension data and gradient data, a weight distribution of the vehicle; determine, in dependence on the determined weight distribution, a distribution of torque to be applied to the wheels of the vehicle so as to match the weight distribution between the one or more wheels; and output, in dependence on the determined distribution of torque, a first control signal to a torque delivery system of the vehicle to redistribute torque applied to the wheels of the vehicle so as to match the weight distribution between the one or more wheels.

The one or more processors may be configured to determine, for each of the one or more wheels, a proportion of a total weight of the vehicle distributed thereto. As such, based on the suspension data and gradient data, the proportion of the total vehicle weight experienced at each wheel is determined. In this respect, when an object to be recovered is attached to a hitch point of the vehicle, the transfer of load to the hitch point can result in the vehicle’s centre of mass from moving towards the hitch point, such that more weight and thus vertical load is experienced at the wheels proximate to said hitch point. Similarly, if the vehicle is on a gradient, a larger proportion of weight may be distributed towards the end of the vehicle facing down the slope.

The one or more processors may be configured to determine, for each of the one or more wheels, a proportion of a total torque to be applied to the wheels of the vehicle, wherein the proportion of the total torque corresponds to the proportion of the total weight distributed to the respective wheel. That is to say, for each wheel, the proportion of the total torque being applied may match the proportion of the vehicle weight at said wheel. For example, if two thirds of the weight is distributed to the rear set of wheels, two thirds of the torque will be distributed to those wheels.

Optionally, the one or more processors may be configured to determine, in dependence on the suspension data and gradient data, a change in a position of the centre of mass of the vehicle, to thereby determine the weight distribution of the vehicle. That is to say, the centre of mass of the vehicle will change position with changes to gradient and the transfer of load from an object (as indicated in the suspension data), which will result in a corresponding change in the weight distribution of the vehicle. For example, if the centre of mass is closerthe rear of the vehicle as a result of the gradient and/or load exerted by an object, a greater proportion of the vehicle’s weight will be distributed to the rear wheels. Optionally, the suspension data may comprise data indicative of a displacement of the suspension system at the one or more wheels of the vehicle and/or air pressure delivered to the suspension system at the one or more wheels of the vehicle.

In this way, variations in the suspension system of the first vehicle can be used to monitor changes in the vertical load experienced by the wheels of the vehicle.

Optionally, the one or more processors may be further configured to receive resistance data indicative of a rolling resistance between the vehicle and a surface on which the vehicle is located, determine, in dependence on the gradient data, resistance data and suspension data, a target limit of a torque to be applied by a drivetrain of the vehicle to move the object, and output, in dependence on the determined target limit of torque, a second control signal to the torque delivery system so as to control an amount of torque applied to the wheels of the vehicle, wherein the amount of torque applied to the wheels is redistributed in accordance with the first control signal.

In this way, the vehicle may be recovered more efficiently because the vehicle performing the recovery is less likely to suffer loss of traction during the recovery process. The target limit of torque corresponds to the amount of longitudinal force that needs to be applied to the wheels of the first vehicle by the drivetrain to move the second vehicle from its stationary position, whilst at the same time maintaining enough traction between the wheels of the first vehicle and the ground to avoid any slip, thus enabling the first vehicle to recover the second vehicle more effectively. As such, the target limit causes the torque delivery system to ensure that the torque applied by the drivetrain does not exceed the target limit as the first vehicle is moved, even if a user demands more, the torque applied being redistributed in accordance with the determined torque distribution.

Optionally, the one or more processors may be configured to determine, in dependence on the suspension data, a load on the hitch point from the object. That is to say, based on changes in the suspension height proximate to the hitch point, the transfer of load from the object to the hitch point can be determined.

Optionally, the one or more processors may be configured to receive the resistance data from a tractive resistance system of the vehicle.

Optionally, the one or more processors may be configured to receive a user input signal to the vehicle to activate the recovery mode of the vehicle. Similarly, after determining the torque distribution and/or target torque limit, the one or more processors may be configured to output a signal to a user interface of the vehicle instructing a user to move the vehicle, to thereby move the object.

Optionally, the one or more processors may be configured to receive the gradient data and suspension data when the vehicle is operating in the recovery mode and prior to torque being applied by the torque delivery system. Similarly, the one or more processors may be configured to determine the weight distribution and the distribution of torque when the vehicle is operating in the recovery mode and prior to torque being applied by the torque delivery system. In this way, torque is only redistributed according to weight distribution during recovery operations.

Optionally, the one or more processors may be configured to update the distribution of torque in dependence on further received gradient data and suspension data. As such, if there are changes to the load experienced at each wheel, such that the weight distribution changes, the distribution of torque can be dynamically updated. For example, if the recovery begins with the vehicle facing uphill, a larger proportion of the weight will be distributed to the rear wheels initially, and thus a larger proportion of torque is required at the rear wheels to overcome the vertical load. If the vehicle moves onto a flat surface as it moves, the weight distribution will change such that less of the weight will be distributed to the rear wheels, and thus the torque distribution at the rear wheels can be correspondingly reduced.

Optionally, the one or more processors may be configured to receive the gradient data from an inertial measurement unit of the vehicle.

Optionally, the torque delivery system may comprise a torque on demand system or a torque biasing system.

Optionally, the one or more wheels comprise one or more of a first set of wheels coupled to a rear axle of the vehicle, and a second set of wheels coupled to a front axle of the vehicle.

Optionally, the one or more wheels may comprise a pair of wheels proximate to the hitch point.

According to another aspect of the invention, there is provided a system comprising the control system as mentioned above and torque delivery system of the vehicle.

According to yet another aspect of the invention, there is provided a vehicle comprising the system as mentioned above or the control system as mentioned above.

According to a further aspect of the invention, there is provided a method for controlling a recovery mode of a vehicle for recovery of an object connected to a hitch point of the vehicle. The method comprises receiving suspension data from a suspension system of the vehicle, the suspension data being indicative of a vertical load on one or more of wheels of the vehicle, and receiving gradient data indicative of a gradient of the vehicle. The method also comprises determining, in dependence on the suspension data and gradient data, a weight distribution of the vehicle, and determining, in dependence on the determined weight distribution, a distribution of torque to be applied to the wheels of the vehicle so as to match the weight distribution between the one or more wheels. The method also comprises outputting, in dependence on the determined distribution of torque, a first control signal to a torque delivery system of the vehicle to redistribute torque applied to the wheels of the vehicle so as to match the weight distribution between the one or more wheels.

According to a still further aspect of the invention, there is provided a computer readable instructions which, when executed by a computer, are arranged to perform the method as mentioned above. Within the scope of this application it is expressly intended that the various aspects, embodiments, examples and alternatives set out in the preceding paragraphs, in the claims and/or in the following description and drawings, and in particular the individual features thereof, may be taken independently or in any combination. That is, all embodiments and/or features of any embodiment can be combined in any way and/or combination, unless such features are incompatible. The applicant reserves the right to change any originally filed claim or file any new claim accordingly, including the right to amend any originally filed claim to depend from and/or incorporate any feature of any other claim although not originally claimed in that manner.

BRIEF DESCRIPTION OF THE DRAWINGS

One or more embodiments of the invention will now be described, by way of example only, with reference to the accompanying drawings, in which:

Figure 1 shows a block diagram illustrating a control system according to an embodiment of the present invention;

Figure 2A shows a schematic illustration of a vehicle according to an embodiment of the present invention; Figure 2B shows a schematic illustration of a rear-view of the vehicle of Figure 2A;

Figure 3 shows a first flowchart showing operations performed by the control system of Figure 1 according to an embodiment of the present invention;

Figure 4 shows a second flow chart showing operations performed by the control system of Figure 1 according to an embodiment of the present invention;

Figure 5 shows a schematic illustration of the operation of the vehicle of Figure 2A during the operations performed by the control system of Figure 1 ;

Figures 6A-6B show a schematic illustration of the operation of the vehicle of Figure 2A during the operations performed by the control system of Figure 1 .

DETAILED DESCRIPTION

With reference to Figure 1 , there is illustrated a control system 100 for a vehicle. The control system 100 as illustrated in Figure 1 comprises one controller 110, although it will be appreciated that this is merely illustrative. The controller 1 10 comprises processing means 120 and memory means 130. The processing means 120 may be one or more electronic processing device 120 which operably executes computer-readable instructions. The memory means 130 may be one or more memory device 130. The memory means 130 is electrically coupled to the processing means 120. The memory means 130 is configured to store instructions, and the processing means 120 is configured to access the memory means 130 and execute the instructions stored thereon.

The controller 110 comprises an input means 140 and an output means 150. The input means 140 may comprise an electrical input 140 of the controller 110. The output means 150 may comprise an electrical output of the controller 110. The input means140 is arranged to receive a suspension system signal 160 from a suspension system of the vehicle. The suspension system signal 160 is an electrical signal which is indicative of changes in one or more characteristics of the suspension system of the vehicle, such as the height and/or air pressure of the front and/or rear suspension of the vehicle, which in turn is indicative of changes in the vertical load experienced by wheels of the vehicle. The input means 140 is also arranged to receive a vehicle orientation signal 162 from one or more sensors of the vehicle, for example, an inertial measurement unit (IMU) of the vehicle. The vehicle orientation signal 162 is an electrical signal which is indicative of one or more characteristics of the position and orientation of the vehicle, including but not limited to, the gradient (i.e., the pitch) of the vehicle, a rotation of the vehicle (e.g., the rotation of the vehicle about its yaw axis) and a lateral movement of the vehicle (e.g., the lateral movement of the vehicle about its roll axis). The input means 140 is further arranged to receive a tractive resistance signal 164 from a tractive resistance system of the vehicle. The tractive resistance signal 164 is an electrical signal which is indicative of a rolling resistance between the wheels of the vehicle and the surface on which the vehicle is located. The tractive resistance signal 164 may also comprise data indicative of one or more of a coefficient of friction between wheels of the vehicle and the surface on which the vehicle is located. The input means 140 may also be optionally arranged to receive a recovery mode signal 166 from a user via a human-machine interface (HMI) of the vehicle 200 instructing the controller 110 to start operating the vehicle in a recovery mode which aids an assisted recovery of a second vehicle. The input means 140 may be further optionally arranged to receive a torque signal 168 from a torque delivery system of the vehicle. The torque signal 168 is an electrical signal which is indicative of the amount of torque being delivered to the drivetrain and/or the wheels of the vehicle.

The output means 150 is arranged to output a torque distribution signal 170 to a torque delivery system of the vehicle to request a redistribution of the torque applied to one or more wheels of the vehicle. The torque distribution signal 170 being indicative of a distribution of torque to be applied to the wheels of the vehicle so as to match the vertical load on one or more of the wheels of the vehicle. The output means 150 may also be optionally arranged to output a driver control signal 172 to a human-machine interface (HMI) of the vehicle requesting the driver of the vehicle to move the vehicle. In cases where the vehicle is an autonomous or semi- autonomous vehicle, it will be appreciated that the driver control signal 172 may be output to an autonomous control system. The output means 150 may be further optionally arranged to output a torque control signal 174 to a torque delivery system of the vehicle, the torque control signal 174 being indicative of an amount of torque to be applied to the wheels of the vehicle.

Figure 2A illustrates a vehicle 200 according to an embodiment of the present invention. The vehicle 200 comprises a controller 100 as illustrated in Figure 1 . The controller 110 is shown as mounted within the vehicle 200 and is in communication with a torque delivery system 220 located within the vehicle 200 such that the torque distribution signal 170 and torque control signal 174 can be transmitted to the torque delivery system 220. The torque delivery system 220 may comprise one or more of a torque on demand system and a torque biasing system. A torque on demand system is configured to control the amount of torque delivered to each set of wheels of the vehicle 200. Similarly, a torque biasing system is configured to distribute torque to each set of wheels of the vehicle 200, typically, such that more torque is applied to the set of wheels having the highest level of traction.

The controller 110 is in further communication with one or more components of a suspension system 225 such that the suspension signal 160 can be received from the suspension system 225. The controller 110 is in further communication with an inertial measurement unit 230 such that the orientation signal 162 can be received from the inertial measurement unit 230. The controller 110 may also be in further communication with one of further control systems (not shown) located within the vehicle 200 such that the control signal 172 can be transmitted to the further control systems including, but not limited to, a human-machine interface or an autonomous control system.

Vehicle 200 may be an EGO vehicle, i.e., a vehicle that is equipped with autonomous or semi-autonomous driving technology and is capable of sensing and navigating its environment without direct input from a human driver.

Vehicle 200 has at least one hitch point for connecting the vehicle 200 to an object in need of recovery. For example, vehicle 200 may have a first hitch point 210A located at the front of the vehicle 200, proximate to a front set of wheels 280A, 280B. It will of course be appreciated that this is purely illustrative and the first hitch point 210A may be located at any suitable position on the front of the vehicle 200. Similarly, there may be more than one hitch point located on the front of the vehicle 200.

Figure 2B illustrates a rear-view of the vehicle 200 of Figure 2A. The vehicle 200 may also have a second hitch point 210B located at the rear of the vehicle 200 proximate to a rear set of wheels 280C, 280D, for connecting the vehicle 200 to an object in need of recovery. It will again be appreciated that this is purely illustrative and the second hitch point 210B may be located at any suitable position on the rear of the vehicle 200. Similarly, there may be multiple hitch points on the rear of the vehicle 200. It will also be appreciated that the vehicle 200 may have one or both of the first and second hitch points 210A, 210B. The hitch points 210A, 210B provide a connection point, to which a rope or some other connection means may be attached to the vehicle 200, to thereby connect the vehicle 200 to an object in need of recovery.

The torque delivery system 220 may be configured to provide torque to the wheels 280A-D. In this respect, it will be appreciated that the wheels 280A-D may be controlled individually, with torque being delivered directly to one or more of the wheels 280A-D by the torque delivery system 220. Optionally, the front set of wheels 280A, 280B may be coupled to a first axle, and the rear set of wheels 280C, 280D may be coupled to a second axle. The torque delivery system 220 may thus be configured to provide torque to one or both of the first and second axles to thereby provide torque to at least one wheel 280A-D.

It will of course be appreciated that the vehicle 200 may be operated to assist in the recovery of any suitable object, including but not limited to, a second vehicle, a trailer, a boat, a boulder, wood logs, or any object having weight that does not exceed the power capabilities of the vehicle 200.

Figure 3 is a flowchart 300 according to an embodiment of the present invention. The flowchart 300 illustrates steps performed by the control system 100 in controlling a recovery mode of a vehicle 200, such as the vehicle 200 illustrated in Figures 2A and 2B and with further reference to Figure 5 and Figures 6A-B. In particular, the memory 130 may comprise computer-readable instructions which, when executed by the processor 120, perform the method 300 according to an embodiment of the invention. In the example shown in Figure 5, the vehicle 200 is providing assisted recovery to a recovery vehicle 250, a front hitch point 255A of the recovery vehicle 250 being attached to the rear hitch point 21 OB of the vehicle 200 by a connecting means such as a tow rope 260. It will of course appreciate that this is merely illustrative, and that the recovery vehicle 250 may be replaced with any object in need of being recovered or moved to another location.

At step 310, the control system is 100 is configured to receive suspension data of the vehicle 200. The suspension data is received as an input signal 160 at the input means 140 of the controller 110 and comprises data indicative of a vertical load on one or more wheels 280A-D of the vehicle 200. In this respect, the suspension data 160 comprises data indicative of a displacement of the suspension system 225, which may be measured as one example, by one or more position sensors, or in cases where the suspension system 225 is a self-levelling air suspension system, the suspension data 160 may comprise data indicative of a change in air pressure supplied to the suspension system 225 to change or to maintain the ride height of the vehicle 200. Any displacement of the suspension system 225 at one or more of the wheels 280A-D of the vehicle 200 is thus indicative of a change in the vertical load on at least one of the wheels 280A-D of the vehicle 200. For example, as shown in Figure 5, a decrease in height B of the suspension of the vehicle 200 proximate to the hitch point 210B, that is, a decrease in the height B of the suspension at the rear end of the vehicle 200, is indicative of an increase in the vertical load A on at least one of the rear set of wheels 280C, due to the increase in load at the hitch point 210B. The increase in vertical load A on the rear set of wheels 280C may also lead to a decrease in vertical load on one or more the front set of wheels 280A, which will be indicated in the suspension data 160 as an increase in height of the suspension at the front of the vehicle 200. In this respect, it will be appreciated that the amount of load on each set of wheels 280A-D will also be dependent on the weight of the object connected to the hitch point 210A, 210B and the gradient of the surface 270 on which the vehicle 200 and object are located.

At step 320, the control system 100 is configured to receive gradient data of the vehicle 200. The gradient data is received as an input signal 162 at the input means 140 of the controller 110 and comprises data indicative of a gradient of the vehicle 200 as measured by one or more sensors, such as an inertial measurement unit (IMU) 230 of the vehicle 200. It will be appreciated that the gradient of the vehicle 200 is in turn indicative of the incline of a surface 270 on which the vehicle 200 is positioned. In the example shown in Figure 5, the surface 270 is shown as being substantially horizontal, but it will be appreciated that the surface 270 may be inclined, for example, when the vehicle 200 is on a hill.

It will of course be appreciated that the steps 320 and 330 may be performed in parallel or in sequence, and that the data may be received as input signals 160 and 162 at the same time or in any order.

At step 330, the processing means 120 of the control system 100 is configured to determine the distribution of weight over the vehicle 200 in dependence on the suspension data and the gradient data. In this respect, the processing means 120 receives the input signals 160 and 162 from the input means 140 and, upon executing the instructions stored in the memory means 130, determines the weight distribution of the vehicle 200. Figures 6A-B provide an example for illustrating how the distribution of weight may be determined. Figure 6A shows the vehicle 200 prior to any load being applied to a hitch point 210A, 21 OB. At a zero gradient, assuming the front wheels 280A-B and rear wheels 280C-D are approximately equal distance from the vehicle’s central point (i.e., the centre of mass C), the weight (shown generally at A and B) at each set of wheels 280A-B, 280C- D will be approximately % mg (where m is vehicle mass, and g is gravity), and the suspension heights and/or air pressure (as generally denoted by D and E) will be approximately equal. If the vehicle is on an incline, it will be appreciated that the weight of the vehicle may not be evenly distributed in this way.

As illustrated in Figure 6B, when an object (not shown) is connected to the rear hitch point 21 OB (e.g., via a tow rope 260), this causes a transfer of load from the front wheels 280A-B to the rear wheels 280C-D, thus causing a shift in the position of the centre of mass (denoted by C) towards the rear wheels 280C-D, and a change in the weight (i.e., vertical load) experienced at each set of wheels 280A-B, 280C-D. As a result, the suspension data 160 may indicate changes to the suspension height and/or air pressure at each end of the vehicle 200. For example, the suspension height at the front of the vehicle 200 (denoted by D) may increase, whilst the suspension height at the rear of the vehicle 200 (denoted by E) may decrease as a result of the additional load on the rear hitch point 210B. Based on the relative changes in the suspension data 160 at each wheel 280A-D or each set of wheels 280A-D, a new position of the centre of mass can be calculated, from which a new weight distribution can be derived. For example, the centre of mass may shift to 5/8 of the distance from the front wheels 280A-B to the rear wheels 280C-D (i.e., 5/8 of the wheelbase), and thus the weight (denoted by A) experienced at the front wheels 280A may reduce to 3/8mg (i.e., 3/8 of the total weight), whilst the weight (denoted by B) experienced at the rear wheels 280C may increase to 5/8mg (i.e., 5/8 of the total weight). It will of course be appreciated that, in the case of an object being connected to the front hitch point 210A, load would instead be transferred to the front wheels 280A-B of the vehicle 200, and thus the weight experienced at the front wheels 280A-B would be greater than that at the rear wheels 280C-D.

As such, given the known weight of the vehicle 200 at zero gradient and without any external load applied to the vehicle 200 by an object, changes in the suspension data 160 at each wheel 280A-D can be used to determine changes in the distribution of weight, such that a proportion of the total weight exerted on each wheel 280A-D may be determined. In this respect, it will be appreciated that the weight of the vehicle 200, the distance between the wheels 280A-D, and the suspension height and/or air pressure at zero gradient may be stored as data in the memory means 130. It will also be appreciated that the relationship between changes in the suspension height and/or pressure with the position of the centre of mass of the vehicle 200 may be predetermined and stored as data (e.g., in a look-up table) in the memory means 130 for use by the processing means 120 to determine the weight distribution Alternatively, the processing means 120 may be configured to determine the position of the centre of mass by executing instructions stored in the memory means 130, wherein said instructions are configured to calculate the position of the centre of mass based on changes in the suspension data 160 and other known parameters of the vehicle 200 (e.g., the weight of the vehicle 200, the distance between the wheels 280A-D, and the suspension height and/or air pressure at zero gradient).

Whilst the present example shows a scenario in which the gradient is zero, it will of course be appreciated that the weight distribution may be further affected by gradient data 162 indicative of a non-zero gradient. For example, if the vehicle 200 was facing in an up-hill direction, the load transfer towards the rear wheels 280C- D may be further increased as a result. Similarly, if the vehicle 200 was facing in a down-hill direction, the amount of load transferred towards the rear wheels 280C-D may be less than on a zero gradient, and depending on the amount of incline, load may instead be transferred to the front wheels 280A-B as a result (i.e., the amount of load at the rear wheels 280C-D is reduced). As such, the angle of incline derived from the gradient data 162 may be used to further adjust the weight distribution as a result of this gradient, for example, by calculating a relative change in the position of the centre of mass at that angle and adjusting the weight distribution accordingly. It will also be appreciated that the relationship between gradient and the position of the centre of mass may also be stored as data (e.g., in a look up table) in the memory means 130 for use by the processing means 120. Alternatively, the processing means 120 may be configured to determine the position of the centre of mass by executing instructions stored in the memory means 130, wherein said instructions are configured to calculate the position of the centre of mass based on changes in the gradient data 162.

At step 340, based on the determined weight distribution, the processing means 120 of the control system 100 is configured to determine a distribution of torque to be applied to the wheels of the vehicle 200 so as to match the weight distributed between the wheels 280A-D. For example, if a larger vertical load (i.e., larger weight distribution) is measured on one or both of the wheels proximate to the hitch point 210A, 210B that is coupled the object (e.g., vehicle 250 in Figure 5), the processing means 120 will determine that a larger proportion of torque should be applied to those wheels 280A-D to match the weight distributed to those wheels 280A-D. Taking the example provided above, where the weight (denoted by A) experienced at the front wheels 280A- B is approximately 3/8mg and the weight (denoted by B) experienced at the rear wheels 280C-D is approximately 5/8mg, 3/8 of the torque to be applied may be distributed to the front wheels 280A-B, whilst 5/8 of the torque to be applied may be applied to the rear wheels 280C-D. As such, the proportion of torque to be applied at each wheel 280A-D matches the proportion of weight at each wheel 280A-D.ln this respect, the wheel torque to be applied in order to move the vehicle 200 may be determined by multiplying the tractive effort at each wheel 280A-D by the wheel radius, wherein the tractive effort is defined as the coefficient of friction, p, multiplied by the weight at each wheel 280A-D. In this respect, the coefficient of friction may be received as input signal 164 from the tractive resistance system of the vehicle 200. Similarly, it will be appreciated that the wheel radius may be stored as data in the memory means 130. Using the above example, if the vehicle 200 is travelling on a smooth surface (e.g., a tarmac road), the coefficient of friction may be estimated at approximately 1 . Given a wheel radius of 0.5 metres, the processing means 120 will determine the torque to be applied at the front wheels 280A-B to be 3/16mg Nm. Similarly, the processing means 120 will determine the torque to be applied at the rear wheels 280C-D to be 5/16mg Nm. It will also be appreciated that the proportion of torque distributed to each set of wheels 280A-B, 280C-D may be split between the respective wheels of said set of wheels 280A-B, 280C-D. In this respect, the proportion of torque at each set of wheels 280A-B, 280C-D may be divided equally, or proportionally if a greater proportion of the weight distribution is experienced at one wheel 280A-D (e.g., the wheel closest to the hitch point 210B). Once the processing means 120 has determined the required distribution of torque, the controller outputs, at step 350, a control signal 170 to cause the torque delivery system 220, which may include a torque on demand system or torque biasing system, to redistribute the torque being applied to the wheels 280A-D.

In this way, when an object to be recovered is attached to a hitch point 210A, 21 OB of the vehicle 200, such that the vehicle 200 has an uneven distribution of weight, the torque delivery system 220 is controlled so as to match the torque applied to each wheel 280A-D to the corresponding vertical load on each wheel 280A-D. This maximises the longitudinal force delivered to the wheels experiencing the most load and ensures that the maximum amount of longitudinal force is not delivered to the wheels 280A-D where there is less vertical load to overcome, which could otherwise cause those wheels 280A-D to spin since there is not enough available traction between the wheels 280A-D and the ground 270.

Optionally, before the suspension data 160 is received at step 310, the control system 100 may be configured to receive user input data from a human-machine interface of the vehicle 200. The user input data is received as an input signal 164 at the input means 140 of the controller 100 and comprises data indicating a request to begin operating in the recovery mode of the vehicle 200.

Optionally, once the torque distribution signal 170 has been output to the torque delivery system 220, the controller 110 may be configured to output a signal 172 to a human-machine interface of the vehicle 200 instructing the driver of the vehicle 200 to begin moving the vehicle 200 forward so as to move the object (e.g., recovery vehicle 250), if not already doing so.

It will be appreciated that steps 310-350 may be performed at one or more of the following points in time: prior to torque being applied by the torque delivery system 220; upon torque being applied to the torque delivery system 220; repeatedly regardless of whether or not torque is being applied by the torque delivery system 220. Additionally, it will be appreciated that the suspension data 160 and gradient data 162 may be received throughout the recovery of the object, continuously or repeatedly, such that the distribution of torque is updated if and when one or more of the input signals 160 and 162 changes. As such, the input signals 160 and 162 may be received at a first point in time before the assisted recovery has commenced, or at a time when the vehicle 200 has been connected to an object and moved forward enough that the tow rope 260 has been brought under tension to thereby transfer an initial load from the object to the hitch point 210A, 210B of the vehicle 200. In doing so, coarse measurements of the suspension data can be received and input as input signal 160, to thereby determine an initial torque distribution. As such, the torque distribution may be first determined at step 340 when an initial load is sensed via a change to the input signal 160. The input signals 160 and 162 are then repeatedly received as the assisted recovery is carried out and torque is applied by the torque delivery system 220, the torque distribution being continuously adjusted and refined as further data is received.

Figure 4 is a flowchart 400 according to an embodiment of the present invention. The flowchart 400 illustrates steps performed by the control system 100 in controlling a recovery mode of a vehicle 200, such as the vehicle 200 illustrated in Figures 2A and 2B and with further reference to Figure 5, which may be used in conjunction with the method described with reference to Figure 3. In particular, the memory 130 may comprise computer- readable instructions which, when executed by the processor 120, perform the method 400 according to an embodiment of the invention.

At step 410, the control system 100 is configured to receive gradient data of the vehicle 200. As before, the gradient data is received as input signal 162 at the input means 140 of the controller 1 10 and comprises data indicative of a gradient of the vehicle 200.

At step 420, the control system 100 is configured to receive tractive resistance data of the vehicle 200. The tractive resistance data is received as an input signal 164 at the input means 140 of the controller 110 and comprises data indicative of a rolling resistance between the vehicle 200 and the surface 270 on which the vehicle 200 is located, and more specifically, between the wheels 280A-D of the vehicle 200 and the below surface 270. The rolling resistance will depend on the vertical load exerted on the wheels (for example, as determined at step 310 above) and the rolling resistance factor between the wheels and the surface 270, the rolling resistance factor being the measure of drag force generated by the wheels as it moves on and through a deformable surface such as mud. For example, the rolling resistance factor for a set of tyres moving along a smooth paved road will have a lower rolling resistance factor than that for a set of tyres moving along a muddy or sandy surface. The tractive resistance data may be measured by a tractive resistance system of the vehicle 200. In this respect, it will be appreciated that the rolling resistance factor may be estimated by a variety of different systems within the vehicle 200, for example, using torque sensors or torque measurements from the powertrain in relation to the gradient and speed of the vehicle 200.

At step 430, the control system 100 is configured to receive suspension system data of the vehicle 200. As before, the suspension system data is received as an input signal 160 at the input means 140 of the controller 110 and comprises data indicative of a change in the height of the suspension of the vehicle 200 proximate to at least one of the hitch points 210A, 210B, that is, a change in the height of the suspension at the front and/or rear end of the vehicle 200. As discussed above, changes in the height of the suspension system 225, or changes to the air pressure in the suspension system 225, is indicative of any changes in the load exerted on the hitch point 210B, since this increase in load will cause a corresponding increase in the vertical load and cause the suspension to compress. The suspension system data of the vehicle 200 can thus be used by the processor 120 to determine the load on the hitch point 210B. For example, when an object such as a recovery vehicle 250 is attached to the vehicle 200 via the rear hitch point 210B, as shown in Figure 5, and the tow rope 260 is brought under tension, the vehicle 200 will experience an increase of load at the hitch point 210B, which will in turn cause a proportional increase in the vertical load B, and thus a displacement in the rear suspension or a change in air pressure supplied to the rear suspension. In this respect, it will again be appreciated that the amount of load on the hitch point 210B will be dependent on the weight of the object (e.g., recovery vehicle 250), the gradient of the surface 270 on which the object and vehicle 200 are located and the direction in which the vehicle 200 is pulling the object along that gradient (i.e., uphill or downhill).

It will of course be appreciated that the steps 410, 420 and 430 may be performed in parallel or in sequence, and that the input signals 160, 162 and 164 may be received at the same time or in any order. At step 440, the control system 100 is configured to determine a target limit of torque to be applied by the drivetrain of the vehicle 200 based on the gradient data, the tractive resistance data and the load determined from the suspension data. In this respect, the processing means 120 receives the input signals 160, 162 and 164 from the input means 140 and, upon executing the instructions stored in the memory means 130, determines the target limit of torque to be applied by the drivetrain. The target limit of torque corresponds to the amount of longitudinal force that needs to be applied to the wheels 280A-D of vehicle 200 by the drivetrain to move the object from its stationary position, whilst at the same time maintaining enough traction between the wheels 280A-D of the vehicle 200 and the ground 270 to avoid any wheel slip.

Once the processing means 120 has determined the target limit of torque to be applied by the drivetrain of the vehicle 200, the controller 110 outputs, at step 450, a control signal 174 to cause the torque delivery system 220 of the vehicle 200 to control the amount of torque applied to the wheels 280A-D of the vehicle 200 in dependence on the target limit of torque, wherein the amount of torque applied to the wheels 280A-D is redistributed in accordance with the torque distribution signal 170 output at step 350 above. In this respect, the torque delivery system 220 may be configured to control the drivetrain such that, as power is applied to the drivetrain, the amount of torque applied by the drivetrain does not exceed the determined target limit.

As such, the target limit causes the torque delivery system 220 to ensure that the torque applied by the drivetrain does not exceed the target limit as the vehicle 200 is moved, even if a user demands more, the torque applied being redistributed in accordance with the determined torque distribution.

Once an initial target limit of torque has been determined and the torque control signal 174 has been output to the torque delivery system 220, steps 410-440 may be repeated so as to adjust the target limit of torque and amount of torque applied throughout the assisted recovery. In this respect, the control system 100 is configured to repeatedly or continuously receive input signals 160, 162 and 164, the determined target limit of torque changing if and when one or more of the input signals 160, 162 and 164 changes.

In this respect, it will be appreciated that the input signals 160, 162 and 164 may be received at any appropriate time, including but not limited to, prior to any torque being applied by the torque delivery system 220, upon torque being applied by the torque delivery system 220, and repeatedly regardless of whether or not torque is being applied by the torque delivery system 220. As such, the input signals 160, 162 and 164 may be received at a first point in time before the assisted recovery has commenced, or at a time when the vehicle 200 has been connected to an object and moved forward enough that the tow rope 260 has been brought under tension to thereby transfer an initial load from the object to the hitch point 210A, 210B of the vehicle 200. In doing so, coarse measurements of the suspension data and tractive resistance data can be received and input as input signals 160 and 164, to thereby determine an initial target limit of torque. As such, the target limit of torque may be first determined at step 440 when an initial load is sensed via a change to the input signal 160 following activation of the recovery mode. The input signals 160, 162 and 164 are then repeatedly received as the assisted recovery is carried out and torque is applied by the torque delivery system 220, the target limit of torque being continuously adjusted and refined as further data is received. In this regard, if upon determining the target limit of torque, torque is applied by the drivetrain up to that target limit and no movement of the vehicle 200 is detected, the target limit of torque may be gradually increased until the vehicle 200 begins to move. Similarly, the target limit of torque may be gradually reduced as the vehicle 200 moves, for example, if the suspension data indicates that the vertical load at the hitch point 210A, 210B has decreased due to the vehicle 200 travelling down a gradient.

It will be appreciated that various changes and modifications can be made to the present invention without departing from the scope of the present application.

Claims

1 . A control system for controlling a recovery mode of a vehicle for recovery of an object connected to a hitch point of the vehicle, the control system comprising one or more processors collectively configured to: receive suspension data from a suspension system of the vehicle, the suspension data being indicative of a vertical load on one or more wheels of the vehicle; receive gradient data indicative of a gradient of the vehicle; determine, in dependence on the suspension data and gradient data, a weight distribution of the vehicle; and determine, in dependence on the determined weight distribution, a distribution of torque to be applied to the wheels of the vehicle so as to match the weight distribution between the one or more wheels; and output, in dependence on the determined distribution of torque, a first control signal to a torque delivery system of the vehicle to redistribute torque applied to the wheels of the vehicle so as to match the weight distribution between the one or more wheels.

2. A control system according to claim 1 , wherein the one or more processors are configured to determine, for each of the one or more wheels, a proportion of a total weight of the vehicle distributed thereto.

3. A control system according to claim 2, wherein the one or more processors are configured to determine, for each of the one or more wheels, a proportion of a total torque to be applied to the wheels of the vehicle, wherein the proportion of the total torque corresponds to the proportion of the total weight distributed to the respective wheel.

4. A control system according to any preceding claim, wherein the one or more processors are configured to determine, in dependence on the suspension data and gradient data, a change in a position of the centre of mass of the vehicle, to thereby determine the weight distribution of the vehicle.

5. A control system according to any preceding claim, wherein the suspension data comprises data indicative of a displacement of the suspension system at the one or more wheels of the vehicle and/or air pressure delivered to the suspension system at the one or more wheels of the vehicle.

6. A control system according to any preceding claim, wherein the one or more processors are further configured to: receive resistance data indicative of a rolling resistance between the vehicle and a surface on which the vehicle is located; determine, in dependence on the gradient data, resistance data and suspension data, a target limit of a torque to be applied by a drivetrain of the vehicle to move the object; and output, in dependence on the determined target limit of torque, a second control signal to the torque delivery system so as to control an amount of torque applied to the wheels of the vehicle, wherein the amount of torque applied to the wheels is redistributed in accordance with the first control signal.

7. A control system according to claim 6, wherein the one or more processors are configured to determine, in dependence on the suspension data, a load on the hitch point from the object.

8. A control system according to any preceding claim, wherein the one or more processors are configured to receive the gradient data and suspension data when the vehicle is operating in the recovery mode and prior to torque being applied by the torque delivery system.

9. A control system according to any preceding claim, wherein the one or more processors are configured to determine the weight distribution and the distribution of torque when the vehicle is operating in the recovery mode and prior to torque being applied by the torque delivery system.

10. A control system according to any preceding claim, wherein the one or more processors are configured to update the distribution of torque in dependence on further received gradient data and suspension data.

11 . A control system according to any preceding claim, wherein the one or more wheels comprise one or more of a first set of wheels coupled to a rear axle of the vehicle, and a second set of wheels coupled to a front axle of the vehicle.

12. A control system according to any preceding claim, wherein the one or more wheels comprise a pair of wheels proximate to the hitch point.

13. A system comprising the control system of any preceding claim and torque delivery system of the vehicle.

14. A vehicle comprising the system of claim 13 or the control system of claims 1 to 12.

15. A method for controlling a recovery mode of a vehicle for recovery of an object connected to a hitch point of the vehicle, the method comprising: receiving suspension data from a suspension system of the vehicle, the suspension data being indicative of a vertical load on one or more of wheels of the vehicle; receiving gradient data indicative of a gradient of the vehicle; determining, in dependence on the suspension data and gradient data, a weight distribution of the vehicle; and determining, in dependence on the determined weight distribution, a distribution of torque to be applied to the wheels of the vehicle so as to match the weight distribution between the one or more wheels; and outputting, in dependence on the determined distribution of torque, a first control signal to a torque delivery system of the vehicle to redistribute torque applied to the wheels of the vehicle so as to match the weight distribution between the one or more wheels.