WO2024256234A1

WO2024256234A1 - Assisted recovery mode

Info

Publication number: WO2024256234A1
Application number: PCT/EP2024/065426
Authority: WO
Inventors: James Coleman; Aaron Ward; Rowena FURBY; Jim Kelly; 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: 2024-12-19
Anticipated expiration: 2025-12-12
Also published as: GB2631156A; GB202406872D0; GB202406873D0; GB2631155A; GB202308724D0; GB202406874D0; GB2631154A; GB2631081A; GB2631081B

Abstract

Aspects of the present invention relate to a control system (100) for controlling a recovery mode of a vehicle (200) for recovery of a second vehicle (250) connected to a hitch point (210A-B) of the first vehicle (200), the control system (100) comprising one or more controllers (110), the control system (100) configured to receive (320) a first signal (160) indicative of a gradient of the first vehicle (200); receive (330) a second signal (162) indicative of a rolling resistance between the first vehicle (200) and a surface (270) on which the first vehicle (200) is located; receive (340) a third signal (164) indicative of a load on the hitch point (210A-B) from the second vehicle (250); determine (350), in dependence on the first, second and third signals, a target limit of a torque to be applied by a drivetrain of the first vehicle (200) to move the second vehicle (250); and output (360) a control signal (180) comprising the target limit to a torque delivery system (220) of the first vehicle (200). Aspects of the invention also related to a system incorporating a control system (100) and a torque delivery system (220) of a vehicle (200), a vehicle (200) incorporating a control system (100), and a method (300) of controlling a recovery mode of a first 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 another (a second) 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 second vehicle from moving. To provide recovery assistance, the vehicle will usually be connected to the second vehicle via a hitch point and a tow rope. The vehicle will then drive to pull the second vehicle 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 second vehicle 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 limit of torque to be applied to a drivetrain of a vehicle performing the recovery depending on factors relevant to said vehicle.

According to an aspect of the present invention there is provided a control system for controlling a recovery mode of a first vehicle for recovery of a second vehicle connected to a hitch point of the first vehicle, the control system comprising one or more controllers. The control system is configured to receive a first signal indicative of a gradient of the first vehicle, receive a second signal indicative of a rolling resistance between the first vehicle and a surface on which the first vehicle is located, and receive a third signal indicative of a load on the hitch point from the second vehicle. The control system is further configured to determine, in dependence on the first, second and third signals, a target limit of a torque to be applied by a drivetrain of the first vehicle to move the second vehicle. The control system is further configured to output a control signal comprising the target limit to a torque delivery system of the first vehicle.

In this way, a 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 recoverthe second vehicle more effectively.

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 a first signal indicative of a gradient of the first vehicle; receive a second signal indicative of a rolling resistance between the first vehicle and a surface on which the first vehicle is located; receive a third signal indicative of a load on the hitch point from the second vehicle; determine, in dependence on the first, second and third signals, a target limit of a torque to be applied by a drivetrain of the first vehicle to move the second vehicle; and output a control signal comprising the target limit to a torque delivery system of the first vehicle.

Optionally, the control system is configured to receive the first signal from an inertial measurement unit of the first vehicle.

Optionally, the control system is configured to receive the second signal from a tractive resistance system of the first vehicle.

Optionally, the control system is configured to receive the third signal from a suspension system of the first vehicle, the third signal indicating a displacement of the suspension system proximate the hitch point or a change in air pressure to a self-levelling air suspension system. In this way, variations in the suspension system of the first vehicle can be used to measure increases of load at the hitch point due to the second vehicle.

Optionally, the control system is configured to determine the load on the hitch point in dependence on the third signal.

Optionally, the control system is configured to output, after determining the target limit, a signal to a user interface of the vehicle instructing a user of the first vehicle to move the first vehicle, to thereby move the second vehicle. In this way, once the target limit of torque has been determined and output to the torque delivery system, the user is notified that the first vehicle is ready to begin the recovery of the second vehicle.

Optionally, the control system is configured to adjust the target limit in dependence on changes to one or more of the first, second or third signals. In this way, the target limit is dynamically updated throughout the recovery process. For example, measurements made in relation to gradient, rolling resistance and load on the hitch point may change or become more accurate as the first vehicle moves, and thus the target limit of torque needed to move the second vehicle will also change accordingly.

Optionally, the control system is configured to adjust the target limit as torque is being applied by the drivetrain. Optionally, the control system is configured to adjust the target limit to a new target limit if no movement of the first vehicle is detected when torque is applied at the target limit. In this way, if the target limit of torque is not sufficient to enable the first vehicle to be moved forward, the target limit will be adjusted to cause the torque delivery system to allow more torque to be applied to the drivetrain.

Optionally, outputting of 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. That is to say, the torque delivery system uses the control signal comprising the target limit of torque to control the amount of torque applied to the drivetrain even if the user demands torque above the target limit, to thereby prevent the vehicle losing traction as a result of too much torque being applied.

Optionally, the control system is configured to output a control signal to a suspension system of the first vehicle to lift a suspension proximate to the hitch point of the first vehicle such that the hitch point is lifted to an increased height relative to the surface. For example, the hitch point of the first vehicle may be lifted up to its maximum ride height. By lifting the hitch point of the first vehicle, this will cause the hitch point of the second vehicle to lift, thereby reducing the vehicle load on the second vehicle and transferring that load to the hitch point of the first vehicle, thereby making it easier for the first vehicle to move the second vehicle.

Optionally, the control system is configured to monitor changes in air pressure of the suspension system as the hitch point is lifted to the increased height.

Optionally, the control system is configured to determine, in dependence on the changes in air pressure, a transfer of a load from the second vehicle to the hitch point of the first vehicle as a result of the hitch point being lifted.

Optionally, the control system is configured to receive a user input signal to the first vehicle to activate the recovery mode of the first vehicle.

Optionally, the control system is configured to receive the first, second and third signals and determine the target limit at one or more of the following points in time: prior to any torque being applied by the torque delivery system; upon torque being applied by the torque delivery system; repeatedly regardless of whether or not torque is being applied by the torque delivery system.

Optionally, the control system is configured to determine the target limit of a torque to be applied when an initial load is transferred from the second vehicle to the hitch point of the first vehicle. For example, the control system may be configured to sense the initial load when there is a change to the third signal following activation of the recovery mode. In this respect, the initial load may be transferred when a connection means between the second vehicle and the hitch point of the first vehicle is brought under tension.

Optionally, the control system is configured to receive torque data from the torque delivery system of the first vehicle; determine, in dependence on the target limit, a tractive effort of the wheels of the first vehicle; and output a control signal to a braking system of the first vehicle to control a braking of the wheels as the measured tractive effort approaches a first threshold. In this respect, the wheels may be the pair of wheels proximate the hitch point. In this way, the control signal may cause the braking system to pre-load the braking applied to the wheels as the tractive effort approaches the threshold of tractive limit to provide more traction between the wheels of the vehicle and the ground, and then gradually reduce the braking once the tractive effort reaches the threshold to allow the vehicle to slowly start to move away without significant wheel slip.

Optionally, the control system is configured to calculate a weight distribution of the first vehicle; and output, based on the calculated weight distribution, a control signal to a torque on demand or other torque biasing system of the first vehicle to redistribute torque to the pair of wheels proximate the hitch point. In this way, the control signal causes the torque on demand or other torque biasing system 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.

Optionally, the control system is configured to calculate the weight distributions in dependence on suspension data received from a suspension system of the first vehicle, and/or the first signal.

Optionally, the control system is configured to receive lateral positions data indicative of a lateral movement of the first vehicle; receive steering wheel angle data indicative of an angular position of a steering wheel of the first vehicle; determine, in dependence on the lateral position data and steering wheel angle data, whether to operate one or more systems of the first vehicle to control a lateral movement thereof; and output, in dependence on the determining, a control signal to request the one or more systems to control the lateral movement of the first vehicle. For example, if the recovery is taking place on a curved road, the steering wheel may be turned at an angle, in which case some lateral movement is required. However, if there is no angle applied to the steering of the vehicle, and the lateral position data indicates that the vehicle is leaning to one side, this lateral movement could reduce the amount of effective longitudinal force achieved as torque is applied by the drivetrain, and therefore needs to be offset.

Optionally, the one or more systems comprises at least one of a braking system of the first vehicle, a suspension system of the first vehicle and one or more individual corner motors of the first vehicle.

According to another aspect of the invention, there is provided a system comprising the control system as mentioned above and a torque delivery system of a first 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 first vehicle for recovery of a second vehicle connected to a hitch point of the first vehicle. The method comprises receiving a first signal indicative of a gradient of the first vehicle, receiving a second signal indicative of a rolling resistance between the first vehicle and a surface on which the first vehicle is located, and receiving a third signal indicative of a load on the hitch point from the second vehicle. The method further comprises determining, in dependence on the first, second and third signals, a target limit of a torque to be applied by a drivetrain of the first vehicle to move the second vehicle. The method further comprises outputting a control signal comprising the target limit to a torque delivery system of the first vehicle.

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

Figure 4 shows a schematic illustration of the operation of the vehicle of Figure 2a during the operations performed by the control system of Figure 1

Figure 5 shows a second flow chart showing operations performed by the control system of Figure 1 according to an embodiment of the present invention;

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

Figures 7A-B show a schematic illustration of the operation of the vehicle of Figure 2a during operations performed by the control system of Figure 1 ;

Figure 8 shows a third flowchart showing operations performed by the control system of Figure 1 according to an embodiment of the present invention; Figure 9 shows a fourth flowchart showing operations performed by the control system of Figure 1 according to an embodiment of the present invention;

Figure 10 shows a fifth flowchart showing operations performed by the control system of Figure 1 according to an embodiment of the present invention.

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 110 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 1 10. The output means 150 may comprise an electrical output of the controller 110. The input means 140 is arranged to receive a position signal 160 from an inertial measurement device of the vehicle. The position signal 160 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, the yaw of the vehicle and the roll of the vehicle. The input means 140 is also arranged to receive a tractive resistance signal 162 from a tractive resistance system of the vehicle. The tractive resistance signal 162 is an electrical signal which is indicative of a rolling resistance between the vehicle and the surface on which the vehicle is located. The input means140 is further arranged to receive a suspension system signal 164 from a suspension system of the vehicle. The suspension system signal 164 is an electrical signal which is indicative of the state or changes in one or more characteristics of the suspension system of the vehicle, such as the height and/or air pressure (where the suspension system is an air suspension system) of the front and/or rear suspension of the vehicle, which in turn is indicative of the state or changes in the load experienced by the vehicle. 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 to aid 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 input means 140 may also be optionally arranged to receive a steering angle signal 170 from a steering wheel position sensor of the vehicle.

The output means 150 is arranged to output a torque control signal 180 to a torque delivery system of the vehicle, the torque control signal 180 being indicative of a target limit of a torque to be applied by a drivetrain of the vehicle during the assisted recovery of a second vehicle. The output means 150 may be optionally arranged to output a suspension control signal 182 to the suspension system of the vehicle to request the suspension system to lift the front or rear suspension of the vehicle to an increased height. The output means 150 may also be optionally arranged to output a driver control signal 184 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 184 may be output to an autonomous control system. The output means 150 may also be optionally arranged to output a brake control signal 186 to a braking system of the vehicle to control one or more braking characteristics of the vehicle. The output means 150 may be further optionally arranged to output a torque distribution signal 188 to a torque on demand system or torque biasing system of the vehicle to request a redistribution of the torque applied to one or more wheels of the vehicle.

Figure 2A illustrates a vehicle 200 according to an embodiment of the present invention. The vehicle 200 comprises a controller 110 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 control signal 180 can be transmitted to the torque delivery system 220. The controller 110 is in further communication with one or more components of a suspension system 225 such that the suspension height signal 164 can be received from the suspension system 225, and optionally, the suspension control signal 182 can be transmitted to the suspension system 225. 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 signals 184-188 can be transmitted to the plurality of further control systems. The plurality of further control systems may include, but not limited to, one or more of a torque on demand system, a torque biasing system, a humanmachine interface, and a braking system of the vehicle.

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 a second vehicle in need of recovery. For example, vehicle 200 may have a first hitch point 210A located at the front of the vehicle 200. 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.

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 for connecting the vehicle 200 to a second vehicle 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. 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 a vehicle in need of recovery.

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 4. 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 4, the vehicle 200 (also referred to herein as the first vehicle) is providing assisted recovery to a second vehicle 250, a front hitch point 255A of the second vehicle 250 being attached to the rear hitch point 210B of the vehicle 200 by a connecting means such as a tow rope 260.

Optionally, at step 310, the control system is 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 166 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.

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 160 at the input means 140 of the controller 110 and comprises data indicative of a gradient of the vehicle 200 as measured by an inertial measurement unit (IMU) 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 4, 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.

At step 330, 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 162 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 of the vehicle 200 and the surface 270. The rolling resistance will depend on the vertical load exerted on the wheels (shown for example purposes by arrow A in Figure 4) 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 (indicating greater traction) 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 340, the control system 100 is configured to receive suspension system data of the vehicle 200. The suspension system data is received as an input signal 164 at the input means 140 of the controller 110 and comprises data indicative of the height, and more particularly in a change in the height (shown for example purposes by arrow B in Figure 4) 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 B of the suspension at the front and/or rear end of the vehicle 200. The suspension system data may comprise 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 system data 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. As discussed above, changes in the height B 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 21 OB, since this increase in load will cause a corresponding increase in the vertical load A and cause the suspension to compress. A self-levelling air suspension system will operate to counter the compressive force. 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 a second vehicle 250 is attached to the vehicle 200 via the rear hitch point 210B, as shown in Figure 4, 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 be appreciated that the amount of load on the hitch point 210B will be dependent on the weight of the second vehicle 250 and the gradient of the surface 270 on which the second vehicle 250 is located.

It will of course be appreciated that the steps 320, 330 and 340 may be performed in parallel or in sequence, and that the input signals 162, 164 and 166 may be received at the same time or in any order.

At step 350, 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 system 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 of vehicle 200 by the drivetrain to move the second vehicle 250 from its stationary position, whilst at the same time maintaining enough traction between the wheels 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 1 10 outputs, at step 360, a control signal 180 to cause the torque delivery system 220 of the vehicle 200 to control the drivetrain as power is applied thereto. In this respect, the torque delivery system 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.

Optionally, once an initial target limit of torque has been output to the torque delivery system 220, the controller 110 may be configured to output, at step 370, a signal 184 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 second vehicle 250, if not already doing so.

Once an initial target limit of torque has been determined and output to the torque delivery system 220, steps 320-350 can be repeated so as to adjust the target limit of torque throughout the assisted recovery. In this respect, the control system 100 is configured to repeatedly 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 the second vehicle 250 and moved forward enough that the tow rope 260 has been brought under tension to thereby transfer an initial load from the second vehicle 250 to the hitch point 210A, 210B of the vehicle 200. In doing so, coarse measurements of the tractive resistance data and the suspension system data can be received and input as input signals 162 and 164, to thereby determine an initial target limit of torque. As such, the target limit of torque may be first determined at step 350 when an initial load is sensed via a change to the input signal 164 following activation of the recovery mode at step 310. 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.

Figure 5 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 Figures 6A and 6B. As before, in the example shown in Figures 6A and 6B, the vehicle 200 is providing assisted recovery to a second vehicle 250, the front hitch point 255A of the second vehicle 250 being attached to the rear hitch point 210B of the vehicle 200 by a tow rope 260.

Steps 310, 320, 330, 340, 350 and 360 are the same as illustrated in Figure 3 and their discussion is not repeated in detail for brevity. However, compared to Figure 3, the flowchart 400 of Figure 5 contains a further step 355 at which the control system 1 10 is configured to output a control signal 182 to cause the suspension system 225 of the vehicle 200 to lift the suspension proximate to the hitch point 210B to an increased height (as shown for example purposes by arrow B), for example, up to the maximum ride height, such that the hitch point 210B is lifted relative to the ground 270, as shown in Figure 6A. In this respect, the control signal 182 may cause the suspension system 225 to increase the air pressure in the suspension proximate to the hitch point 210B to thereby increase the height B of the rear suspension of the vehicle 200. In doing so, the hitch point 255A of the second vehicle 250 will also begin to lift, thereby reducing the vertical load (shown for example purposes by arrow C) at the front end of the second vehicle 250, resulting in an increase of load on the hitch point 210B of the vehicle 200. This in turn will produce an increase in vertical load (shown for example purposes by arrow A) on the rear suspension of the vehicle 200 as the load is transferred from the second vehicle 250 to the hitch point 210B of the vehicle 200. Once the suspension proximate to the hitch point 21 OB has been lifted to an increased height, steps 320-350 are repeated to determine any changes to the target limit of torque to be applied as a result of this transfer of load. In this respect, it will be appreciated that there may not be any change to the gradient data received at step 320 (which gradient data may take account of the change in suspension height) and the tractive resistance data received at step 340, although the increase in vertical load A on the vehicle 200 is likely to have an effect on at least the rolling resistance experienced by the vehicle 200. At step 340, the control system 100 is configured to receive suspension system data of the vehicle 200. The suspension system data is received as input signal 164 at the input means 140 of the controller 110 and comprises data indicative of the air pressure delivered to the suspension of the vehicle 200 proximate to the hitch point 210B to maintain the suspension at the increased height as load is transferred from the second vehicle 250 to the hitch point 210B. As described with reference to Figure 3, the suspension system data of the vehicle 200 can thus be used by the processor 120 to determine the transfer of load on the hitch point 210B from the second vehicle 250.

At step 350, the control system 100 is configured to determine a new target limit of torque to be applied by the drivetrain of the vehicle 200 based on the received suspension data, that is, the determined transfer of load, as well as the gradient data received at step 320 and the tractive resistance data received at step 330. As before, the controller 110 will then output, at step 360, a control signal 180 to cause the torque delivery system 220 of the vehicle 200 to control the drivetrain as power is applied thereto.

Whilst step 355 is shown as being performed after steps 320-350 have been performed at least once, it will be appreciated that it may be performed at any time during the assisted recovery and may be carried out prior to the initial target limit of torque being determined. Similarly, once step 355 has been performed, steps 320-350 may be repeatedly performed without repeating step 355 as discussed above with reference to Figure 3.

Figures 7 A and 7B illustrate further examples of the vehicle 200 during an assisted recovery of a second vehicle 250. In Figure 7A, the front hitch point 255A of the second vehicle 250 is attached to a front hitch point 210A of the vehicle 200 via a tow rope 260. In Figure 7B, the back hitch point 255B of the second vehicle 250 is attached to a back hitch point 210B of the vehicle 200 via a tow rope 260. It will thus be appreciated that the vehicle 200 may recover the second vehicle 250 by moving in a forward or reverse direction, with the second vehicle 250 facing in a forward or reverse direction, and the methods described herein being carried out in substantially the same way.

Figure 8 is a flowchart 500 according to an embodiment of the present invention. The flowchart 500 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, which may be used in conjunction with the methods described with reference to Figures 3 and 4. As before, the memory 130 may comprise computer-readable instructions which, when executed by the processor 120, perform the method 500 according to an embodiment of the invention.

Once a target torque limit has been determined, for example, as determined at step 350 described above, the control system 100 is configured, at step 510, to determine a threshold of tractive effort that is required by the wheels of the vehicle 200 to move the second vehicle 250. In general, the tractive effort is determined by the amount of torque being applied at the wheels of the vehicle 200, the radius of the wheels, the gradient of the vehicle 200, the coefficient of friction between the wheels and the surface 270 below (e.g., as estimated by the braking or tractive resistance systems of the vehicle 200), and the rolling resistance between the wheels and the surface 270. As such, the processing means 120, upon executing the instructions stored in the memory means 130, determines the threshold of tractive effort based on the determined target torque limit, the radius of the wheels of the vehicle 200, which may be stored as data in the memory means 130, as well as the gradient data, tractive resistance data and the load determined from the suspension system data received as input signals 160,162 and 164.

At step 520, as torque is applied to the drivetrain to move the vehicle 200, the control system 100 is configured to receive torque data of the vehicle 200. The torque data is received as an input signal 168 at the input means 140 of the controller 1 10 and comprises data indicative of the torque being applied to the wheels of the vehicle, and more specifically, the pair of wheels proximate to the hitch point 210A, 210B. From the torque data, at step 530, the processing means 120 is configured to determine the tractive effort of the wheels of the vehicle 200 as torque is being applied, again based on the amount of torque being applied to the wheels of the vehicle 200, the radius of said wheels, the gradient of the vehicle 200, the coefficient of friction between the wheels and the below surface 270, and the rolling resistance between the wheels and the below surface 270.

As the processing means 120 determines the tractive effort of the wheels of the vehicle 200, the controller 110 outputs, at step 540, a control signal 186 to cause a braking system of the vehicle 200 to control the braking applied to the wheels of the vehicle 200 as the measured tractive effort approaches the threshold of tractive effort determined at step 510. In this respect, the control signal 186 may cause the braking system to pre-load the braking applied to the wheels of the vehicle 200 as the measured tractive effort approaches the threshold of tractive limit in order to provide more traction between the wheels of the vehicle 200 and the ground 270, and then gradually reduce the braking applied once the measured tractive effort reaches the threshold of tractive limit, so as to allow the vehicle 200 to slowly start to move away without any significant wheel slip.

Figure 9 is a flowchart 600 according to an embodiment of the present invention. The flowchart 600 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, which may be used in conjunction with the methods described with reference to Figures 3, 4 and 8. As before, the memory 130 may comprise computer-readable instructions which, when executed by the processor 120, perform the method 600 according to an embodiment of the invention.

At step 610, as torque is applied to the drivetrain to the move the vehicle 200, the control system is 100 is configured to receive suspension data of the vehicle. The suspension data is received as an input signal 164 at the input means 140 of the controller 110 and comprises data indicative of a displacement of the suspension system 225 and/or air pressure being delivered to the suspension system 225 at the front and rear end of the vehicle 200, which as discussed above, is indicative of the vertical load on the suspension system 225. At step 620, the control system 100 is configured to receive gradient data of the vehicle 200. The gradient data is received as an input signal 160 at the input means 140 of the controller 110 and comprises data indicative of a gradient of the vehicle 200 as measured by an inertial measurement unit (IMU) of the vehicle 200.

At step 630, the control system 100 is configured to determine the distribution of weight over the first vehicle 200 based on the load determined from the suspension data and/or the gradient data. In this respect, the processing means 120 receives the input signals 160 and 164 from the input means 140 and, upon executing the instructions stored in the memory means 130, determines the weight distribution of the vehicle 200.

At step 640, 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 load on each wheel. For example, if a larger load is measured on one or both of the wheels proximate to the hitch point 210A, 210B, the processing means 120 will determine that a larger proportion of torque should be applied to those wheels to match the load on those wheels. 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 may not be enough available traction between the wheels and the ground 270.

Once the processing means 120 has determined the required distribution of torque, the controller outputs, at step 650, a control signal 188 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.

Figure 10 is a flowchart 700 according to an embodiment of the present invention. The flowchart 700 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, which may be used in conjunction with the methods described with reference to Figures 3, 4, 8 and 9. As before, the memory 130 may comprise computer-readable instructions which, when executed by the processor 120, perform the method 700 according to an embodiment of the invention.

At step 710, the control system 100 is configured to receive lateral position data of the vehicle 200. The lateral position data is received as an input signal 160 at the input means 140 of the controller 110 and comprises data indicative of the yaw ofthe vehicle 200 as measured by an inertial measurement unit (IMU) ofthe vehicle 200. It will be appreciated that the position ofthe vehicle about a yaw axis is indicative of any lateral movement being experienced by the vehicle 200, for example, induced by the load from the second vehicle 250 being applied to a hitch point 210A, 210B that is laterally offset from the longitudinal centre line of the vehicle 200. Such lateral movement can reduce the amount of effective longitudinal force achieved as torque is applied by the drivetrain, which may in turn cause the wheels to slip as the vehicle 200 begins to move.

At step 720, the control system 100 is configured to receive steering angle data of the vehicle 200. The steering angle data is received as an input signal 170 at the input means 140 of the controller 110 and comprises data indicative of the position of the steering wheel, for example, as measured by a steering wheel angle sensor of the vehicle 200, which in turn indicates whether the wheels of the vehicle 200 are orientated away from the longitudinal centre line of the vehicle 200. For example, the assisted recovery may be taking place on a curved road, and so the user may have the steering wheel turned at an angle so that the vehicle 200 moves around the curve of the road, in which case some lateral movement and thus lateral force is required.

At step 730, the control system 100 determines whether to operate one or more systems of the vehicle 200 so as to control the detected lateral movement. The processing means 120 receives the input signals 160 and 170 from the input means 140 and, upon executing the instructions stored in the memory means 130, determines whether to operate one or more systems of the vehicle 200 so as to control the detected lateral movement.

For example, if there is no angle applied to the steering of the vehicle 200, and the lateral position data indicates that the vehicle 200 is leaning to one side, for example, towards the side of the hitch point 210A, 210B (assuming they are not centrally positioned), it may be determined that one or more systems of the vehicle 200 should be operated so as to offset the lateral movement. As one example, a braking system of the vehicle 200 may be controlled so as to keep the wheels of the vehicle 200 in the same line as the longitudinal centre line of the vehicle 200. As another example, one or more individual corner motors of the vehicle 200 may be controlled so as to keep the wheels of the vehicle 200 aligned with the longitudinal centre line of the vehicle 200. As a further example, the suspension system 225 of the vehicle 200 may be controlled so as to lean the vehicle 200 away from the direction of the lateral movement. For example, if there is lateral movement towards the wheel of the vehicle 200 proximate to the hitch point 210A, 210B, the height of the suspension may be adjusted so as to counteract the lateral movement, for example, by increasing the air pressure in the suspension proximate to the hitch point 210A, 210B.

On the other hand, if there is an angle being applied to the steering of the vehicle 200, and the lateral position data indicates that the vehicle 200 is leaning in that same direction, then it may be determined that it is not necessary to offset that lateral movement.

Once the processing means 120 has determined whether to operate one or more systems of the vehicle 200 so as to control the detected lateral movement, the controller 1 10 outputs, at step 740, a control signal to cause one or more systems of the vehicle 200 to control the detected lateral movement. For example, the control signal may be output as a brake control signal 186 to the braking system of the vehicle 200, or a suspension control signal 182 to the suspension system 225 of the vehicle 200. A control signal may also be output to one or more individual corner motors of the vehicle 200.

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 first vehicle for recovery of a second vehicle connected to a hitch point of the first vehicle, the control system comprising one or more controllers, the control system configured to: receive a first signal indicative of a gradient of the first vehicle; receive a second signal indicative of a rolling resistance between the first vehicle and a surface on which the first vehicle is located; receive a third signal indicative of a load on the hitch point from the second vehicle; determine, in dependence on the first, second and third signals, a target limit of a torque to be applied by a drivetrain of the first vehicle to move the second vehicle; and output a control signal comprising the target limit to a torque delivery system of the first vehicle.

2. The control system of claim 1 , wherein the control system is configured to receive the first signal from an inertial measurement unit of the first vehicle.

3. The control system of claims 1 or 2, wherein the control system is configured to receive the second signal from a tractive resistance system of the first vehicle.

4. The control system of any preceding claim, wherein the control system is configured to receive the third signal from a suspension system of the first vehicle, the third signal indicating a displacement of the suspension system proximate the hitch point.

5. The control system of claim 4, wherein the suspension system of the vehicle is a self-levelling air suspension system and the control system is configured to receive the third signal as a change in air pressure to the self-levelling air suspension system.

6. The control system of any preceding claim, wherein the control system is configured to determine the load on the hitch point in dependence on the third signal.

7. The control system of any preceding claim, wherein the control system is configured to adjust the target limit in dependence on changes to one or more of the first, second or third signals.

8. The control system of any preceding claim, wherein the control system is configured to adjust the target limit to a new target limit if no movement of the first vehicle is detected when torque is applied at the target limit.

9. The control system of any preceding claim, wherein the control system is configured to output a control signal to a suspension system of the first vehicle to lift the suspension proximate to the hitch point of the first vehicle such that the hitch point is lifted to an increased height relative to the surface.

10. The control system of claim 9, when dependent on claim 5, wherein the control system is configured to monitor changes in air pressure of the suspension system as the hitch point is lifted to the increased height.

11 . The control system of claim 10, wherein the control system is configured to determine, in dependence on the changes in air pressure of the suspension system, a transfer of a load from the second vehicle to the hitch point of the first vehicle as a result of the hitch point being lifted.

12. A system comprising the control system of any preceding claim and a torque delivery system of a first vehicle.

13. A vehicle comprising the system of claim 12 or the control system of any of claims 1 to 11 .

14. A method for controlling a recovery mode of a first vehicle for recovery of a second vehicle connected to a hitch point of the first vehicle, comprising: receiving a first signal indicative of a gradient of the first vehicle; receiving a second signal indicative of a rolling resistance between the first vehicle and a surface on which the first vehicle is located; receiving a third signal indicative of a load on the hitch point from the second vehicle; determining, in dependence on the first, second and third signals, a target limit of a torque to be applied by a drivetrain of the first vehicle to move the second vehicle; outputting a control signal comprising the target limit to a torque delivery system of the first vehicle.

15. Computer readable instructions which, when executed by a computer, are arranged to perform a method according to claim 14.