A control system for a damper of a suspension system

Abstract

Aspects of the present invention relate to a control system (100), a system (500), a vehicle (600), a method (400) and computer readable instructions. The control system (100) is for controlling at least one damper (142) of a suspension system (140) of a vehicle (600), the vehicle being operable in a plurality of driver modes, the control system comprising one or more processors (102) collectively configured to: receive a drive mode signal (110) indicative of a current drive mode that the vehicle is operating in; receive a terrain roughness signal (130), indicative of a roughness of a terrain that the vehicle is travelling on; determine, in dependence on the roughness of the terrain and the current drive mode, at least one minimum damping level to be provided by the at least one damper; output a minimum damping control signal (120) to control the at least one damper according to the at least one minimum damping level.

Description

[0001] A CONTROL SYSTEM FOR A DAMPER OF A SUSPENSION SYSTEM

[0002] TECHNICAL FIELD

[0003] The present disclosure relates to a control system for a damper of a suspension system. Aspects of the invention relate to a control system, to a system, to a vehicle, to a method and to computer readable instructions.

[0004] BACKGROUND

[0005] It is known to provide a vehicle with a suspension system that has adaptive damping. Adaptive damping is a technology which is used to automatically adjust the stiffness of dampers (for example shock absorbers) in response to varying driving conditions. For example, a vehicle can have different drive modes which have associated settings for the dampers, and the vehicle is configured to control the level of damping of the dampers in accordance with the settings associated with the selected drive mode. For example in a “comfort mode”, the suspension system controls the dampers to be softer, allowing for more absorption of road imperfections and reducing vibrations transmitted to the cabin, resulting in a smooth and comfortable ride. In contrast, in a “sport mode”, the suspension system controls the level of damping of the dampers to be stiffer, resulting in a firmer ride. The selected drive mode and its associated suspension settings may not always provide the most suitable level of damping.

[0006] It is an aim of the present invention to address one or more of the disadvantages associated with the prior art.

[0007] SUMMARY OF THE INVENTION

[0008] Aspects and embodiments of the invention provide a control system, a system, a vehicle, a method and to computer readable instructions as claimed in the appended claims.

[0009] According to an aspect of the present invention there is provided a control system comprising one or more processors collectively configured to: receive a drive mode signal indicative of a current drive mode that a vehicle is operating in; receive a terrain roughness signal, indicative of a roughness of a terrain; determine, in dependence on at least one of the roughness of the terrain and the current drive mode, at least one minimum damping level to be provided by at least one damper; and output a minimum damping control signal to control at least one damper according to the at least one minimum damping level.

[0010] The control system advantageously adjusts a minimum amount of damping provided by dampers of the suspension system according to at least one of drive mode and terrain roughness. This provides damping which is tailored specifically to the manner in which the vehicle is being driven. By controlling damping in dependence upon at least one of drive mode and the terrain roughness, this can improve traction and cabin feel.

[0011] According to an aspect of the present invention there is provided a control system for controlling at least one damper of a suspension system of a vehicle, the vehicle being operable in a plurality of driver modes, the control system comprising one or more processors collectively configured to: receive a drive mode signal indicative of a current drive mode that the vehicle is operating in; receive a terrain roughness signal, indicative of a roughness of a terrain that the vehicle is travelling on; determine, in dependence on the roughness of the terrain and the current drive mode, at least one minimum damping level to be provided by the at least one damper; and output a minimum damping control signal to control the at least one damper according to the at least one minimum damping level.

[0012] The control system therefore advantageously adjusts a minimum amount of damping provided by dampers of the suspension system according to a combination of drive mode and terrain roughness. This provides damping which is tailored specifically to the manner in which the vehicle is being driven, on the terrain it is travelling on. By controlling damping in dependence upon drive mode and the terrain roughness, this can improve traction and cabin feel.

[0013] 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 drive mode signal indicative of a current drive mode that the vehicle is operating in; receive a terrain roughness signal, indicative of a roughness of a terrain that the vehicle is travelling on; determine, in dependence on the roughness of the terrain and the current drive mode, at least one minimum damping level to be provided by the at least one damper; output a minimum damping control signal to control the at least one damper according to the at least one minimum damping level.

[0014] Optionally, the one or more processors are collectively configured to: receive a vehicle dynamics parameter signal indicative of a vehicle dynamics parameter; wherein the determining of the at least one minimum damping level is further dependent upon the vehicle dynamics parameter.

[0015] Advantageously the handling characteristics of the vehicle can therefore be improved by controlling the minimum level of damping to be dependent on vehicle dynamics. For example a higher level of minimum damping may be desirable at higher vehicle speeds and lateral acceleration to improve handling characteristics.

[0016] Optionally, the one or more processors are collectively configured to: determine an intermediate minimum damping level, dependent on the current drive mode and the vehicle dynamics parameter; and determine the at least one minimum damping level by modifying the intermediate minimum damping level depending on the current drive mode and the roughness of the terrain.

[0017] Therefore according to examples disclosed herein, the combination of the vehicle dynamics and the current drive mode may be used to determine the intermediate minimum damping level, which is then further modified according to a combination of the current drive mode and the roughness of the terrain. This advantageously provides damping control which is more sensitive to the terrain the vehicle is driving on as well as the drive mode the vehicle is operating in. This therefore improves damping control and also improves traction and cabin feel.

[0018] Optionally, the intermediate minimum damping level is a first intermediate minimum damping level and the vehicle dynamics parameter is a first vehicle dynamics parameter, and the one or more processors are collectively configured to: determine a second intermediate minimum damping level dependent upon a second vehicle dynamics parameter and the current drive mode, select, as the intermediate minimum damping level, which of the first intermediate minimum damping level and the second intermediate minimum damping level is indicative of a larger level of damping.

[0019] Advantageously, different parameters of the vehicle dynamics can be used to determine the intermediate minimum damping level, which improves the suspension system’s ability to respond to different dynamics of the vehicle to provide damping appropriate for the driving situation.

[0020] Optionally, determining the at least one minimum damping level by modifying the intermediate minimum damping level depending on the current drive mode and the terrain roughness comprises one of: increasing the amount of damping indicated by the at intermediate minimum damping level; decreasing the amount of damping indicated by the intermediate minimum damping level; and maintaining the amount of damping indicated by the intermediate minimum damping level.

[0021] Therefore advantageously, by taking into account the combination of the terrain roughness and the current drive mode, the minimum level of damping can be modified by increasing, decreasing or maintaining it so as to provide specific damping appropriate for the terrain roughness and drive mode.

[0022] Optionally, each drive mode of the plurality of drive modes is associated with vehicle operating settings specific for that drive mode.

[0023] Advantageously the control system is responsive to different drive modes which alter the operation of the vehicle, and therefore can provide appropriate damping for varying driving operations and conditions.

[0024] Optionally, the vehicle operating settings comprise one or more of: engine performance settings; transmission settings; suspension settings; driving assistance settings; traction control settings.

[0025] Advantageously the control system is responsive to different drive modes which each have a large variety of vehicle operating settings, and damping control can be provided for a wide variety of vehicle driving operations and conditions.

[0026] Optionally, the vehicle dynamics parameter comprises at least one of: a velocity of the vehicle; and a lateral acceleration of the vehicle. Advantageously, the handling characteristics of the vehicle can improved by controlling the minimum level of damping in dependence upon the velocity and / or lateral acceleration of the vehicle.

[0027] Optionally, the at least one minimum damping level comprises at least one of: a compression minimum damping level, indicative of an amount of compression damping to be provided by the at least one damper; and a rebound minimum damping level, indicative of an amount of rebound damping to be provided by the at least one damper.

[0028] Advantageously the control system controls the different phases of damping to provide the appropriate minimum level of damping for compression and rebound.

[0029] According to another aspect of the invention, there is provided a system comprising the control system as described herein and a suspension system comprising at least one damper.

[0030] According to another aspect of the invention, there is provided a vehicle comprising the system described herein or the control system described herein.

[0031] Optionally, the vehicle comprises a drive mode control system comprising one or more processors collectively configured to automatically select different drive modes from the plurality of drive modes.

[0032] Advantageously the system or control system therefore can control the minimum level of damping in response to automatic selecting of different drive modes by the vehicle without needing control input by the driver.

[0033] According to another aspect of the invention, there is provided a method for controlling at least one damper of a suspension system of a vehicle, the vehicle being operable in a plurality of driver modes, the method comprising: receiving a drive mode signal indicative of a current drive mode that the vehicle is operating in; receiving a terrain roughness signal, indicative of a roughness of a terrain that the vehicle is travelling on; determining, in dependence on the roughness of the terrain and the current drive mode, at least one minimum damping level to be provided by the at least one damper; outputting a minimum damping control signal to control the at least one damper according to the at least one minimum damping level.

[0034] Advantageously, the method adjusts a minimum amount of damping provided by dampers of the suspension system according to a combination of drive mode and terrain roughness. This provides damping which is tailored specifically to the manner in which the vehicle is being driven, on the terrain it is travelling on. By controlling damping in dependence upon drive mode and the terrain roughness, this can improve traction and cabin feel.

[0035] Optionally, the method comprises receiving a vehicle dynamics parameter signal indicative of a vehicle dynamics parameter; wherein the determining of the at least one minimum damping level is further dependent upon the vehicle dynamics parameter. Advantageously the handling characteristics of the vehicle can therefore be improved by controlling the minimum level of damping to be dependent on vehicle dynamics. For example a higher level of minimum damping may be desirable at higher vehicle speeds and lateral acceleration to improve handling characteristics.

[0036] Optionally, the method comprises: determining an intermediate minimum damping level, dependent on the current drive mode and the vehicle dynamics parameter; and determining the at least one minimum damping level by modifying the intermediate minimum damping level depending on the current drive mode and the roughness of the terrain.

[0037] Therefore according to examples disclosed herein, the combination of the vehicle dynamics and the current drive mode are used to determine the intermediate minimum damping level, which is then further modified according to a combination of the current drive mode and the roughness of the terrain. This advantageously provides damping control which is more sensitive to the terrain the vehicle is driving on as well as the drive mode the vehicle is operating in. This therefore improves damping control and also improves traction and cabin feel.

[0038] Optionally, the intermediate minimum damping level is a first intermediate minimum damping level and the vehicle dynamics parameter is a first vehicle dynamics parameter, and the method optionally comprises: determining a second intermediate minimum damping level dependent upon a second vehicle dynamics parameter and the current drive mode, and selecting, as the intermediate minimum damping level, which of the first intermediate minimum damping level and the second intermediate minimum damping level is indicative of a larger level of damping.

[0039] Advantageously, different parameters of the vehicle dynamics can be used to determine the intermediate minimum damping level, which improves the suspension system’s ability to respond to different dynamics of the vehicle to provide damping appropriate for the driving situation.

[0040] Optionally, the vehicle dynamics parameter comprises at least one of: a velocity of the vehicle; and a lateral acceleration of the vehicle.

[0041] Advantageously, the handling characteristics of the vehicle controlled by the method can improved by controlling the minimum level of damping in dependence upon the velocity and / or lateral acceleration of the vehicle.

[0042] According to another aspect of the invention, there are provided computer readable instructions which, when executed by one or more processors, cause the one or more processors to perform the method as described herein.

[0043] 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.

[0044] BRIEF DESCRIPTION OF THE DRAWINGS

[0045] One or more embodiments of the invention will now be described, by way of example only, with reference to the accompanying drawings, in which:

[0046] Figure 1A shows a control system in accordance with an embodiment of the invention;

[0047] Figure 1 B shows a control system in accordance with an embodiment of the invention;

[0048] Figure 2 shows a control system in accordance with an embodiment of the invention;

[0049] Figure 3 shows a control system in accordance with an embodiment of the invention;

[0050] Figure 4 shows a method in accordance with an embodiment of the invention;

[0051] Figure 5 shows a system in accordance with an embodiment of the invention;

[0052] Figures 6 shows a vehicle in accordance with an embodiment of the invention; and

[0053] Figure 7 shows an example damper in accordance with an embodiment of the invention.

[0054] DETAILED DESCRIPTION

[0055] Figure 1A shows a control system in accordance with an embodiment of the invention. Figure 1A shows a control system 100 for controlling at least one damper 142 of a suspension system 140 of a vehicle, the vehicle being operable in a plurality of driver modes.

[0056] The control system 100 comprises one or more processors 102 collectively configured to: receive a drive mode signal 110 indicative of a current drive mode that the vehicle is operating in; receive a terrain roughness signal 130, which is indicative of a roughness of a terrain that the vehicle is travelling on.

[0057] The one or more processors 102 are further configured to determine, in dependence on the roughness of the terrain and the current drive mode, at least one minimum damping level to be provided by the at least one damper and output a minimum damping control signal 120 to control the at least one damper 142 according to the at least one minimum damping level.

[0058] The terrain roughness signal 130, which is indicative of a roughness of a terrain the vehicle is travelling on, is a state estimation function which aims to estimate a continuous terrain roughness the vehicle is currently on, derived from sensor inputs, and can be calculated using a terrain roughness estimator, also referred to as a road roughness estimator. The road roughness estimator may be a state estimation function within an Integrated Suspension Control System (ISCS). The estimator which determines the terrain roughness signal 130, receives Inertial Measurement Unit (IMU) inputs for roll and pitch rates (rate of change of roll / pitch angle), as well as suspension height sensors and hub vertical accelerometers, and uses these inputs to determine a roughness of the terrain the vehicle is on.

[0059] The function is arranged to estimate for both on-road (including metallised) and off-road surfaces. The output of the function is unitless and scaled between 0 and 1 (0-100%) where 0 is smooth and 1 is maximum road roughness. Within the estimator, the output is referred to as the Road Roughness Index (RRI).

[0060] The drive mode signal 110 indicates a drive mode selected by a driver or from an auto terrain response controller, which automatically determines a drive mode based on sensor inputs. Each drive mode of the plurality of drive modes is associated with vehicle operating settings specific for that drive mode.

[0061] For example, the vehicle operating settings comprise one or more of: engine performance settings; transmission settings; suspension settings; driving assistance settings; traction control settings; braking settings. The selected drive mode has the ability to change calibration of the suspension system 140 to offer different handling characteristics.

[0062] For example the different drive modes can comprise a “comfort mode”, a “sport mode”, a “GGS (Grass, Gravel, Snow) mode”, amongst others. For example in the “sport mode”, throttle response and engine performance may be more responsive to provide faster acceleration, and the suspension may be hardened (i.e. have increased damping) to provide improved handling and the traction control may be lessened. For example in the “comfort mode”, the suspension may be softened (i.e. have less damping), and the throttle response and engine performance may be less sharp or responsive to provide a smoother and comfortable ride. For example in the “GGS mode”, the throttle response may be lowered, the braking may be gentler to provide stability on grass / g rave l / s now, the traction control may become more active and the transmission may select a higher gear. All these settings are done to provide extra stability and grip on grass / g rave l / s now.

[0063] According to examples disclosed herein and shown in Figure 1A, the control system 100 advantageously adjusts a minimum amount of damping provided by dampers 142 of the suspension system 140 according to a combination of drive mode and terrain roughness. This provides damping which is tailored specifically to the manner in which the vehicle is being driven, and on the terrain it is travelling on. By controlling damping in dependence upon drive mode and the terrain roughness, this can improve traction and cabin feel.

[0064] Figure 1 B shows a control system 100 in accordance with an embodiment of the invention. The control system 100 shown in Figure 1 B is similar to the control system 100 shown in Figure 1 A and the one or more processors 102 are also collectively configured to: receive a vehicle dynamics parameter signal 150 indicative of a vehicle dynamics parameter. The determining of the at least one minimum damping level is further dependent upon the vehicle dynamics parameter.

[0065] The vehicle dynamics parameter can include any of the parameters which define the dynamics of the vehicle, for example the forces and motions that affect the vehicle’s movement. For example, the vehicle dynamics parameter comprises at least one of: a velocity of the vehicle and a lateral acceleration of the vehicle. In other examples the vehicle dynamics parameters may include another acceleration of the vehicle, such as longitudinal acceleration, and may include a roll of the vehicle, pitch of the vehicle, yaw of the vehicle, or other movement or forces affecting the vehicle.

[0066] Advantageously the at least one minimum damping level is therefore dependent on the drive mode and the roughness of the terrain, and also on the at least one vehicle dynamics parameter, which relates to forces and motions that affect the vehicle’s movement. Handling characteristics of the vehicle can therefore be improved by controlling the minimum level of damping to be dependent on vehicle dynamics. For example a higher level of minimum damping may be desirable at higher vehicle speeds and lateral acceleration to improve handling characteristics.

[0067] Figure 2 shows a control system 100 in accordance with an embodiment of the invention. The control system 100 comprises one or more processors 102 as shown in Figure 1A and Figure 1 B, although for simplicity the one or more processors 102 are not shown in Figure 2. Figure 2 shows various blocks 210, 220, 230, 240, 250 which illustrate various processes or operations which may be performed by the one or more processors 102. For example each block 210, 220, 230, 240, 250 may be associated with different processors of the one or more processors 102. In other examples each block 210, 220, 230, 240, 250 may be associated with one processor of the one or more processors 102.

[0068] As shown in Figure 2, the control system 100 receives three drive mode signals 110 which are provided to blocks 210, 220 and 230. In some examples these three drive mode signals are provided as separate signals to the control system 100, and in other examples the control system 100 receives a single drive mode signal 110 and distributes the drive mode signal 110 to each of blocks 210, 220, 230. As shown in Figure 2, the control system 100 also receives a first vehicle dynamics parameter 151 , a second vehicle dynamics parameter 152 and the terrain roughness signal 130. The first vehicle dynamics parameter 151 and the second vehicle dynamics parameter 152 are provided to blocks 210, 220 respectively. The terrain roughness signal 130 is provided to block 230.

[0069] According to examples, the control system 100 is configured to determine 240 an intermediate minimum damping level 242 using one or more vehicle dynamics parameters and the current drive mode. The intermediate minimum damping level 242 is then modified 250, using a modifier 232 which is determined using the current drive mode and the terrain roughness, to determine the at least one minimum damping level and providing the minimum damping control signal 120.

[0070] According to examples, instead of receiving two vehicle dynamics parameters, namely the first vehicle dynamics parameters 151 and the second vehicle dynamics parameters 152 as shown in Figure 2, the control system 100 only receives one vehicle dynamics parameter. The one or more processors 102 are collectively configured to: determine 240 an intermediate minimum damping level 242, dependent on the current drive mode and a vehicle dynamics parameter; and determine the at least one minimum damping level by modifying 250 the intermediate minimum damping level depending on the current drive mode and the roughness of the terrain. Therefore according to examples disclosed herein, the combination of the vehicle dynamics and the current drive mode may be used to determine the intermediate minimum damping level 242, which is then further modified according to a combination of the current drive mode and the roughness of the terrain.

[0071] According to examples and as shown in Figure 2, two vehicle dynamics parameters are received and are used to determine the intermediate damping level 242. In particular, according to what is shown in Figure 2, the intermediate minimum damping level is a first intermediate minimum damping level 212 and the vehicle dynamics parameter is a first vehicle dynamics parameter 151 , and the one or more processors are collectively configured to: determine a second intermediate minimum damping level 222 dependent upon a second vehicle dynamics parameter 152 and the current drive mode and selecting, as the intermediate minimum damping level 242, which of the first intermediate minimum damping level 212 and the second intermediate minimum 222 damping level is indicative of a larger level of damping.

[0072] Therefore according to examples, a combination of a first vehicle dynamics parameter 151 and the current drive mode indicated by the drive mode signal 110 are used to determine 210 a first intermediate minimum damping level 212, and a combination of a second vehicle dynamics parameter 152 and the current drive mode indicated by the drive mode signal 1 10 are used to determine 220 the second intermediate minimum damping level 222. In block 240 it is determined which of the first intermediate minimum damping level 212 and the second intermediate minimum damping level 222 is to be used as the intermediate minimum damping level 242. This is determined by determining which of the first intermediate minimum damping level 212 and the second intermediate minimum damping level 222 is indicative of the largest amount of damping. According to examples, the first vehicle dynamics parameter is velocity of the vehicle and the second vehicle dynamics parameter is lateral acceleration of the vehicle. In other examples the first vehicle dynamics parameter and the second vehicle dynamics parameters can be other vehicle dynamics parameters besides the velocity of the vehicle and the lateral acceleration of the vehicle.

[0073] The combination of the current drive mode indicated by the drive mode signal 110 and the terrain roughness signal 130 are used to determine 230 a modifier 232 which is then used to modify 250 the intermediate minimum damping level 242 to provide the at least one minimum damping level provided by the minimum damping control signal 120. This advantageously provides damping control which is more sensitive to the terrain the vehicle is driving on, the vehicle dynamics and the drive mode the vehicle is operating in. This therefore improves damping control and also improves traction and cabin feel.

[0074] Each of the determining 210 of the first intermediate minimum damping level 212, the determining 220 of the second intermediate damping level 222 and the determining 230 of the modifier 232 may be done by determining the specific value based on the variables which are provided to each of the blocks 210, 220, 230. These values of the first intermediate damping level 212, the second intermediate damping level 222 and the modifier 232 can be determined using look-up tables or mapping tables, which store values corresponding to each combination of drive mode and first vehicle dynamics parameter 151 , drive mode and second vehicle dynamics parameter 152, and drive mode and terrain roughness. Alternatively, functions may be provided which define relationships between different variables disclosed herein to provide the first intermediate minimum damping level 212, second intermediate minimum damping level 222 and modifier 232. The look-up tables, mapping tables or functions may be determined through experiment, or alternatively they may be self- taught via a machine-learning algorithm stored in memory and executed by one or more processors, which may be memory means 310 and processing means 320 disclosed herein, or may be present on another controller of the vehicle 600 or elsewhere.

[0075] The minimum damping levels 212, 222, 242 can be implemented on a 0-1 scale of damping where 0 is the minimum amount of damping and 1 being the maximum amount of damping.

[0076] According to examples, the first intermediate minimum damping level 212 and the second intermediate minimum damping level 222 are two sources of minimum damping level which are arbitrated together by taking the maximum value at each time step in block 240. In other words the first intermediate minimum damping level 212 and the second intermediate minimum damping level 222 are two sources of minimum damping level which are compared, and the maximum value at each time step is taken in block 240. At this point the intermediate minimum level of damping 242 may be requested.

[0077] According to examples, the intermediate minimum level of damping 242 sets the smallest percentage of damping that can be requested. For example, a minimum damping request of 0.2 at 50mph in the “comfort mode” drive mode means that in this mode the dampers 142 are outputting a minimum of 20% of their damping force and the dampers 142 can operate between 20% - 100% of their capacity.

[0078] According to examples, the modifier 232 can be used in certain drive modes to modify the minimum damping level set from the drive mode by the intermediate minimum level of damping 242, using the first vehicle dynamics parameter 151 and the second vehicle dynamics parameter 152. As an example, the vehicle can be on grass and the drive mode can be in a “GGS (Grass, Gravel, Snow) mode”. The minimum damping (intermediate minimum damping level 242) set for this mode and vehicle speed (the first vehicle dynamics parameter 151) may be 0.4 (40% damping), but when a rougher patch of grass is detected by a terrain roughness estimator as described herein and the terrain roughness increases, the minimum damping may be reduced to 0.2 (20%) damping by the modifier 232. This may improve traction and cabin feel. The modification can be tuned to subjective feel.

[0079] According to examples, determining the at least one minimum damping level by modifying the intermediate minimum damping level depending on the current drive mode and the terrain roughness comprises one of: increasing the amount of damping indicated by the at intermediate minimum damping level; decreasing the amount of damping indicated by the intermediate minimum damping level; maintaining the amount of damping indicated by the intermediate minimum damping level.

[0080] Therefore beneficially, by taking into account the combination of the terrain roughness and the current drive mode, the minimum level of damping can therefore be modified by increasing, decreasing or maintaining it so as to provide specific damping appropriate for the terrain roughness and drive mode. According to examples, the at least one minimum damping level comprises at least one of: a compression minimum damping level, indicative of an amount of compression damping to be provided by the at least one damper 142; and a rebound minimum damping level, indicative of an amount of rebound damping to be provided by the at least one damper 142. Therefore the minimum damping level can be applied for both the compression and rebound phrases of the damping, thereby providing appropriate damping across all phases of the damping according to the terrain roughness and the drive mode.

[0081] In Figure 2, two vehicle dynamics parameters are received by the control system 100, and intermediate minimum damping levels are calculated for each vehicle dynamics parameters. In other examples, a plurality of vehicle dynamics parameters are received by the control system 100, for example more than two vehicle dynamics parameters are received. Further vehicle dynamics parameters received may include a longitudinal acceleration of the vehicle, a roll of the vehicle, a pitch of the vehicle, a yaw of the vehicle, amongst others. Intermediate minimum damping levels may be calculated for each of the plurality of vehicle dynamics parameters. Each intermediate damping level can be calculated by taking the current drive mode and the vehicle dynamics parameter and determining an intermediate damping level, as shown in Figure 2 for each of the first intermediate damping level 212 and the second intermediate damping level 222. According to examples, the intermediate damping level 242 may be determined 240 by determining which of the plurality of intermediate damping levels indicates the highest (maximum) level of damping.

[0082] Figure 3 shows a control system 100 in accordance with an embodiment of the invention. The control system 100 comprises one or more controller 300.

[0083] The control system 100 is configured to receive a drive mode signal 1 10 from a drive mode selector 350 and a terrain roughness signal 130 from a terrain roughness estimator 360. The control system 110 may then output a minimum damping control signal 120 to control at least one damper 142 of the suspension system 140 of the vehicle.

[0084] The control system 100 as illustrated in Figure 3 comprises one controller 300, although it will be appreciated that this is merely illustrative. The controller 300 comprises processing means 310 and memory means 320. The processing means 310 may be one or more electronic processing device 310 which operably executes computer-readable instructions. The memory means 320 may be one or more memory device 320. The memory means 320 is electrically coupled to the processing means 310. The memory means 320 is configured to store instructions, and the processing means 310 is configured to access the memory means 320 and execute the instructions stored thereon.

[0085] The controller 300 comprises an input means 330 and an output means 340. The input means 330 may comprise an electrical input 330 of the controller 300. The output means 340 may comprise an electrical output 340 of the controller 300. The input 330 is arranged to receive a receive a drive mode signal 110 from a drive mode selector 350 and a terrain roughness signal 130 from a terrain roughness estimator 360. The drive mode signal 110 is an electrical signal which is indicative of a current drive mode, and the terrain roughness signal 130 is an electrical signal which is indicative of a roughness of a terrain that the vehicle is travelling on. The output 340 is arranged to output a minimum damping control signal 120 indicative of at least one minimum damping level for controlling at least one damper 142 of the suspension system 140.

[0086] Figure 4 illustrates a method 400 according to an embodiment of the invention. The method 400 is a method of controlling a vehicle 600, such as the vehicle 600 illustrated in Figure 6. In particular, the method 400 is a method of controlling at least one damper 142 of a suspension system 140. The method 400 may be performed by the control system 100 illustrated in Figures 1A, 1 B, 2, and 3. In particular, the memory 320 may comprise computer-readable instructions which, when executed by the processor 310, perform the method 400 according to an embodiment of the invention.

[0087] The method 400 is for controlling at least one damper 142 of a suspension system 140 of a vehicle, the vehicle being operable in a plurality of drive modes. The method 400 comprises receiving 410 a drive mode signal 110 indicative of a current drive mode that the vehicle is operating in; and receiving 420 a terrain roughness signal 130, indicative of a roughness of a terrain that the vehicle is travelling on. For example the drive mode signal 110 may indicate a drive mode selected by a driver of the vehicle or a drive mode which has been automatically selected by a drive mode selector 350.

[0088] The method 400 additionally comprises determining 430, in dependence on the roughness of the terrain and the current drive mode, at least one minimum damping level to be provided by the at least one damper 142; and outputting 440 a minimum damping control signal 120 to control the at least one damper 142 according to the at least one minimum damping level. For example the drive mode may be a “comfort mode” or another drive mode as described herein, and the roughness of the terrain may be 0.5, which according examples is between the minimum value of 0 (which indicates a smooth surface) and the maximum value of 1 (which indicates a very rough surface). The minimum damping level is therefore chosen to reflect that the vehicle is operating in a “comfort mode” where harsh damping is typically not desired, and is travelling on a surface of average roughness. In this instance the minimum damping level may therefore be set relatively low, compared to say, if the vehicle is operating in a “sport mode” as described herein and is on a terrain with an indicated roughness of 0.7.

[0089] The method 400 may additionally comprise receiving a vehicle dynamics parameter signal 150 indicative of a vehicle dynamics parameter. The determining of the at least one minimum damping level can be further dependent upon the vehicle dynamics parameter. According to examples disclosed herein, the vehicle dynamics parameter can be reflect any of the motions or forces which affect the vehicle’s motion.

[0090] According to examples the method 400 may also additionally comprise: determining an intermediate minimum damping level 242, and dependent on the current drive mode and the vehicle dynamics parameter; determining the at least one minimum damping level by modifying the intermediate minimum damping level depending on the current drive mode and the roughness of the terrain. As described with reference to Figure 2, the minimum damping level can therefore be selected to reflect the specific combination of the current drive mode, the vehicle dynamics parameter and the terrain roughness. According to examples, the intermediate minimum damping level may be a first intermediate minimum damping level 212 and the vehicle dynamics parameter is a first vehicle dynamics parameter 151 , and the method may additionally comprise: determining a second intermediate minimum damping level 222 dependent upon a second vehicle dynamics parameter 152 and the current drive mode, selecting, as the intermediate minimum damping level, which of the first intermediate minimum damping level and the second intermediate minimum damping level is indicative of a larger level of damping. Therefore as described herein with reference to Figure 2, the at least one minimum damping level can be selected depending on which of a plurality of vehicle dynamics parameters indicate the higher level of damping needed.

[0091] According to examples, the vehicle dynamics parameter comprises at least one of: a velocity of the vehicle; and a lateral acceleration of the vehicle. According to examples, the vehicle dynamics parameters may comprise other parameters as described herein.

[0092] According to examples, the at least one minimum damping level may comprise at least one of: a compression minimum damping level, indicative of an amount of compression damping to be provided by the at least one damper; and a rebound minimum damping level, indicative of an amount of rebound damping to be provided by the at least one damper.

[0093] In accordance with an embodiment of the invention, there is provided computer readable instructions which, when executed by one or more processors, for example processors 102, 310 as described in Figures 1A, 1 B, 2, 3, cause the one or more processors 102, 310, to perform the method 400.

[0094] Figure 5 shows a system 500 in accordance with an embodiment of the invention. The system 500 comprises the control system 100 as described herein and a suspension system 140 comprising at least one damper 142. For example the control system can be the control system as described in relation to Figures 1A, 1 B, 2, 3 and the dampers 142 of the suspension system 140 may be as described in relation to Figure 7.

[0095] Figures 6 shows a vehicle 600 in accordance with an embodiment of the invention. The vehicle 600 comprises the system 500 or the control system 100 as described herein.

[0096] The vehicle 600 can comprise a drive mode control system (which can also be referred to as a drive mode selector as described herein) 350 comprising one or more processors collectively configured to automatically select different drive modes from the plurality of drive modes. The drive mode control system 350 can be configured to enable a driver to select a drive mode, using one or more buttons or control switches, an infotainment system screen, or similar. The vehicle 600 may also comprise a terrain roughness estimator 360 as described herein.

[0097] The vehicle 600 comprises a plurality of wheels, each of which comprises a damper 142 of the suspension system 140. Each damper 142 can be controlled by the minimum damping control signal 120, for both compression damping and rebound damping. According to examples, the suspension system 140 and / or the control system 100 and / or the system 500 may form part of an adaptive dynamics system of the vehicle 600.

[0098] Figure 7 shows an example damper 142 in accordance with an embodiment of the invention. The damper 142 comprises a piston rod 700, and a piston 702 attached to the piston rod 700. The damper 142 also comprises a cylinder 710. The piston rod 700 of Figure 7 goes through both ends of the cylinder 710. In other examples, the piston rod 700 only goes through one end of the cylinder 710, and the piston rod 700 may end at the piston 702. The piston rod 702 shown in Figure 7 may have a mount at each end to mount on one end to the body of the vehicle and at the other end to the wheel associated with the damper. In other examples, for example where the piston rod 700 only goes through one end of the cylinder 710, the piston rod 700 may have a mounting to mount on one of the body of the vehicle and the wheel, and the cylinder 710 may have a mounting to mount on the other of the body of the vehicle and the wheel.

[0099] The piston 702 is configured to travel within the volume of the cylinder 710. Hydraulic fluid, air or another fluid may be provided within the cylinder 710 to provide resistance to the movement of the piston 702 within the cylinder 710. The piston 702 comprises a compression valve 720 and a rebound valve 730. The compression valve 720 and the rebound valve 730 are configured to be controlled to vary the amount of fluid allowed through from one side of the piston 702 to the other side, which varies the damping force and therefore the damping level provided by the damper 142. According to examples, the compression valve 720 controls compression damping of the damper 142 according to the compression minimum damping level. The rebound valve 730 controls rebound damping of the damper 142 according to the rebound minimum damping level. In some examples, the rebound valve 730 and the compression valve 720 are part of the same valve.

[0100] 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

CLAIMS1 . A control system for controlling at least one damper of a suspension system of a vehicle, the vehicle being operable in a plurality of driver modes, the control system comprising one or more processors collectively configured to: receive a drive mode signal indicative of a current drive mode that the vehicle is operating in; receive a terrain roughness signal, indicative of a roughness of a terrain that the vehicle is travelling on; determine, in dependence on the roughness of the terrain and the current drive mode, at least one minimum damping level to be provided by the at least one damper; and output a minimum damping control signal to control the at least one damper according to the at least one minimum damping level.

2. A control system as claimed in claim 1 , wherein the one or more processors are collectively configured to: receive a vehicle dynamics parameter signal indicative of a vehicle dynamics parameter; wherein the determining of the at least one minimum damping level is further dependent upon the vehicle dynamics parameter.

3. A control system as claimed in claim 2, wherein the one or more processors are collectively configured to: determine an intermediate minimum damping level, dependent on the current drive mode and the vehicle dynamics parameter; and determine the at least one minimum damping level by modifying the intermediate minimum damping level depending on the current drive mode and the roughness of the terrain.

4. A control system as claimed in claim 3, wherein the intermediate minimum damping level is a first intermediate minimum damping level and the vehicle dynamics parameter is a first vehicle dynamics parameter, and the one or more processors are collectively configured to: determine a second intermediate minimum damping level dependent upon a second vehicle dynamics parameter and the current drive mode; and select, as the intermediate minimum damping level, which of the first intermediate minimum damping level and the second intermediate minimum damping level is indicative of a larger level of damping.

5. A control system as claimed in any of claims 2 to 4, wherein the vehicle dynamics parameter comprises at least one of: a velocity of the vehicle; and a lateral acceleration of the vehicle.

6. A control system as claimed in any preceding claim, wherein the at least one minimum damping level comprises at least one of:a compression minimum damping level, indicative of an amount of compression damping to be provided by the at least one damper; and a rebound minimum damping level, indicative of an amount of rebound damping to be provided by the at least one damper.

7. A system comprising the control system of any preceding claim and a suspension system comprising at least one damper.

8. A vehicle comprising the system of claim 7 or the control system of claims 1 to 6.

9. A vehicle as claimed in claim 8, wherein the vehicle comprises a drive mode control system comprising one or more processors collectively configured to automatically select different drive modes from the plurality of drive modes.

10. A method for controlling at least one damper of a suspension system of a vehicle, the vehicle being operable in a plurality of driver modes, the method comprising: receiving a drive mode signal indicative of a current drive mode that the vehicle is operating in; receiving a terrain roughness signal, indicative of a roughness of a terrain that the vehicle is travelling on; determining, in dependence on the roughness of the terrain and the current drive mode, at least one minimum damping level to be provided by the at least one damper; and outputting a minimum damping control signal to control the at least one damper according to the at least one minimum damping level.

11. A method as claimed in claim 10, comprising: receiving a vehicle dynamics parameter signal indicative of a vehicle dynamics parameter; wherein the determining of the at least one minimum damping level is further dependent upon the vehicle dynamics parameter.

12. A method as claimed in claim 11 , comprising: determining an intermediate minimum damping level, dependent on the current drive mode and the vehicle dynamics parameter; and determining the at least one minimum damping level by modifying the intermediate minimum damping level depending on the current drive mode and the roughness of the terrain.

13. A method as claimed in claim 12, wherein the intermediate minimum damping level is a first intermediate minimum damping level and the vehicle dynamics parameter is a first vehicle dynamics parameter, wherein the method comprises: determining a second intermediate minimum damping level dependent upon a second vehicle dynamics parameter and the current drive mode; andselecting, as the intermediate minimum damping level, which of the first intermediate minimum damping level and the second intermediate minimum damping level is indicative of a larger level of damping.

14. A method as claimed in any of claims 11 to 13, wherein the vehicle dynamics parameter comprises at least one of: a velocity of the vehicle; and a lateral acceleration of the vehicle.

15. Computer readable instructions which, when executed by one or more processors, cause the one or more processors to perform the method according to any of claims 10 to 14.

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