Vehicle recovery system
Patent Information
- Application Number
- PCT/EP2026/058040
- Authority / Receiving Office
- WO · WO
- Patent Type
- Applications
- Current Assignee / Owner
- Priority Date
- 2025-03-21
- Filing Date
- 2026-03-23
- Publication Date
- 2026-09-24
Smart Images
Figure EP2026058040_24092026_PF_FP_ABST
Abstract
Description
[0001] VEHICLE RECOVERY SYSTEM
[0002] TECHNICAL FIELD
[0003] The present disclosure relates to controlling an active vehicle suspension of a vehicle. 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 methods for gaining traction when a vehicle is stuck on a low-traction surface. Traditionally, a user may use external devices such as traction mats or winches to gain traction. Such methods may be impractical and require recovery equipment to be available.
[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 computer readable instructions as claimed in the appended claims.
[0009] According to an aspect of the invention there is provided a control system for an active vehicle suspension of a vehicle, the control system comprising one or more processors collectively configured to:
[0010] receive a body motion signal indicative of oscillation of a body of the vehicle;
[0011] determine an in-phase force for the active vehicle suspension, in dependence on the body motion signal, to assist an extrinsic source of excitation in oscillating the body of the vehicle; and
[0012] output a control signal to the active vehicle suspension, requesting the in-phase force.
[0013] An advantage is an improved control system for aiding traction. The control system provides for improved traction when a vehicle is stuck on a low traction surface. When the control system receives a signal indicative of a rocking of the body of the vehicle, the active suspension provides a force that is in-phase with the oscillation. This advantageously means that a user can rock the vehicle to generate the required motion to help free the vehicle as the assisted vehicle rocking amplifies their efforts, or reduces the level of effort required.
[0014] 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 the body motion signal, determine the in-phase force, and output the control signal.
[0015] Optionally, the one or more processors are collectively configured to:
[0016] receive a speed signal indicative of a vehicle speed of the vehicle;
[0017] determine that the vehicle speed is zero or less than a threshold; and
[0018] initiate outputting the control signal requesting the in-phase force, at least in dependence on the vehicle speed being zero or less than the threshold.
[0019] An advantage is improved confidence that assisted vehicle rocking is required and / or that the oscillation will not affect moving vehicle dynamics. Zero speed indicates that the vehicle is stuck.
[0020] Optionally, the one or more processors are collectively configured to:receive a user input signal from a human-machine interface, the user input signal requesting or permitting the control system to assist the extrinsic source of excitation; and
[0021] initiate outputting the control signal requesting the in-phase force, at least in dependence on receiving the user input signal.
[0022] An advantage is improved confidence that assisted vehicle rocking is required, because the assisted vehicle rocking only commences when the user confirms or requests it.
[0023] Optionally, the one or more processors are collectively configured to:
[0024] determine that the oscillation of the body of the vehicle has an intensity greater than a minimum threshold; and initiate outputting the control signal requesting the in-phase force, at least in dependence on the oscillation having an intensity greater than the minimum threshold.
[0025] An advantage is improved confidence that assisted vehicle rocking is required by avoiding commencing the assisted vehicle rocking when the source of the oscillation is irrelevant, such as wind buffeting.
[0026] Optionally, the one or more processors are collectively configured to:
[0027] determine that a slope angle of the vehicle is within a limit; and
[0028] initiate outputting the control signal requesting the in-phase force, at least in dependence on the slope angle of the vehicle being within the limit.
[0029] An advantage is improved confidence that assisted vehicle rocking will adhere to vehicle limits such as vehicle body roll or pitch limits.
[0030] Optionally, the one or more processors are collectively configured to:
[0031] determine that closures of the vehicle are in a closed state; and
[0032] initiate outputting the control signal requesting the in-phase force, at least in dependence on the closures being in the closed state.
[0033] An advantage is improved confidence that assisted vehicle rocking will not result in closures colliding with objects if the vehicle moves.
[0034] Optionally, the oscillation indicated by the body motion signal comprises roll oscillation, and wherein the in-phase force comprises a vehicle roll force.
[0035] An advantage is improved assisted vehicle rocking because the vehicle may be easier to rock in the roll axis. Furthermore, a user can be stood by the side of the vehicle rocking the vehicle and is therefore not in the path of the vehicle.
[0036] Optionally, the one or more processors are collectively configured to:
[0037] inhibit provision of the in-phase force, in dependence on the body motion signal comprising an above-threshold pitch component.
[0038] An advantage is improved confidence that assisted vehicle rocking is required, because a large pitch component of the oscillation may indicate that the cause of the rocking is not a person stood by the side of the vehicle rocking it from side to side.Optionally, the one or more processors are collectively configured to:
[0039] monitor the body motion signal over a predetermined time period; and
[0040] determine a timing of the in-phase force in dependence on the body motion signal over the predetermined time period, to assist the extrinsic source of excitation in oscillating the body of the vehicle, and wherein the timing is selected from the range 1 Hz to 3Hz.
[0041] An advantage is an improved assisted vehicle rocking because a person stood by a vehicle rocking it from side to side is likely to impart a 1-3Hz oscillation.
[0042] Optionally, the in-phase force comprises a predetermined amplitude, or wherein an amplitude of the in-phase force is dependent on an amplitude of the body motion signal.
[0043] An advantage improved assisted vehicle rocking. A fixed force may be applied to provide a baseline level of assistance to make it easier to rock the vehicle, or a feedback loop may be present to maintain a specific level of assistance or even amplify the user’s force.
[0044] Optionally, the one or more processors are collectively configured to: output a further control signal configured to tune a natural frequency of the active vehicle suspension to a frequency of the oscillation.
[0045] An advantage is improved assisted vehicle rocking. By tuning the natural frequency of the active vehicle suspension to a frequency of the oscillation, the vehicle becomes easier to rock.
[0046] Optionally, the one or more processors are collectively configured to:
[0047] inhibit requesting the in-phase force in dependence on a predetermined time period elapsing, the predetermined time period having a duration selected from the range 3 to 30 seconds or 3 to 10 seconds after initiation of requesting the in-phase force.
[0048] An advantage is improved assisted vehicle rocking. If the in-phase force is applied for the above predetermined time period and the vehicle is still stuck in the low traction-surface, then the vehicle is most likely too stuck to be freed by the assisted vehicle rocking. This prevents the in-phase force from being applied continuously in scenarios where it is not helping.
[0049] Optionally, the one or more processors are collectively configured to: inhibit requesting the in-phase force in dependence on any of the following conditions no longer being satisfied: vehicle speed below the speed threshold, user input signal received from the human-machine interface, oscillation of the body of the vehicle having an intensity greater than a minimum threshold, the slope angle of the vehicle is within the limit, and the closures of the vehicle are in a closed state.
[0050] An advantage is that assisted vehicle rocking is inhibited in dependence on any of the entry conditions not being satisfied.
[0051] Optionally, the one or more processors are collectively configured to: inhibit-requesting the in phase in dependence on the oscillation amplitude being above a threshold
[0052] An advantage is that in scenarios where a very large amplitude of oscillation is applied, assisted vehicle rocking is prevented.According to another aspect of the invention there is provided a system comprising the control system and the active vehicle suspension.
[0053] According to a further aspect of the invention there is provided a vehicle comprising the control system, or the aforementioned system.
[0054] According to a further aspect of the invention there is provided a method of controlling an active vehicle suspension of a vehicle, the method comprising:
[0055] receiving a body motion signal indicative of oscillation of a body of the vehicle;
[0056] determining an in-phase force for the active vehicle suspension, in dependence on the body motion signal, to assist an extrinsic source of excitation in oscillating the body of the vehicle; and
[0057] outputting a control signal to the active vehicle suspension, requesting the in-phase force.
[0058] According to a further aspect of the invention there is provided computer readable instructions which, when executed by a computer, are arranged to perform any one or more of the methods described herein. According to a further aspect of the invention there is provided a non-transitory computer readable medium comprising computer readable instructions that, when executed by one or more electronic processors, causes the one or more electronic processors to carry out any one or more of the methods described herein.
[0059] According to a further aspect of the invention there is provided a method or control system for an active vehicle suspension of a vehicle, the method comprising, or the control system comprising one or more processors collectively configured to:
[0060] determine an oscillation force for the active vehicle suspension; and
[0061] output a control signal to the active vehicle suspension, requesting the oscillation force.
[0062] 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 falls within the scope of the appended claims. That is, all embodiments and / or features of any embodiment can be combined in any way and / or combination that falls within the scope of the appended claims, 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.
[0063] BRIEF DESCRIPTION OF THE DRAWINGS
[0064] One or more embodiments of the invention will now be described, by way of example only, with reference to the accompanying drawings, in which:
[0065] FIG. 1 illustrates a perspective view illustrating an example of a vehicle;
[0066] FIGS. 2A-2D illustrate a body of the vehicle being oscillated by an extrinsic human source of excitation;
[0067] FIG. 3 schematically illustrates a vehicle and an active vehicle suspension;
[0068] FIG. 4 schematically illustrates a control system;
[0069] FIG. 5 schematically illustrates a non-transitory computer-readable storage medium; and
[0070] FIG. 6 schematically illustrates a flowchart illustrating an example method.
[0071] DETAILED DESCRIPTIONA vehicle 1 in accordance with an embodiment of the present invention is described herein with reference to the accompanying FIG. 1. In some, but not necessarily all examples, the vehicle 1 is a passenger vehicle, also referred to as a passenger car or as an automobile. In other examples, embodiments of the invention can be implemented for other applications, such as commercial vehicles.
[0072] FIG. 1 is a front perspective view and illustrates a longitudinal x-axis between the front and rear of the vehicle 1 representing a centreline, an orthogonal lateral y-axis between left and right lateral sides of the vehicle 1 , and a vertical z-axis. A forward / fore direction typically faced by a driver’s seat is in the negative x-direction; rearward / aft is +x. A rightward direction as seen from the driver’s seat is in the positive y-direction; leftward is -y. These are a first lateral direction and a second lateral direction. Vehicle body roll is in the y-z plane. Vehicle body pitch is in the x-z plane. Vehicle body yaw is in the x-y plane.
[0073] FIG. 1 illustrates a vehicle body 2 mounted to a set of vehicle wheels 3 by an active vehicle suspension (shown later). The vehicle body 2 is part of the sprung mass of the vehicle 1 , and the suspension and vehicle wheels 3 are part of the unsprung mass of the vehicle 1.
[0074] When a vehicle 1 has become stuck on a low-traction surface such as mud or snow, users may attempt various techniques to recover the vehicle 1 before resorting to winching the vehicle 1. One technique involves at least one human, such as a passenger, standing next to the vehicle 1 and rocking the body 2 of the vehicle 1 back and forth. If this is performed in-phase with a natural frequency of the vehicle suspension at the same time as the driver applies steering or propulsion controls, then the repetitive loading and unloading of the wheels 3 can become sufficient to aid traction and unstick the vehicle wheels 3 from the surface.
[0075] FIGS. 2A-2D illustrate the technique.
[0076] Up to time t_1 in FIG. 2A, the human has pushed the side of the body 2 (sprung mass) of the vehicle 1 while stood to the left or right side of the vehicle 1. This force has induced a roll acceleration F_<j> which has caused the roll angle <j> of the body 2 of the vehicle 1 to change by a few degrees, away from the human.
[0077] From time t_1 of FIG. 2A to time t_2 of FIG. 2B, the human has stopped applying the pushing force to the side of the body 2, allowing the reaction force from the suspension of the vehicle 1 to return the roll angle <j> towards a neutral static equilibrium angle. However, if the suspension is underdamped, the roll angle <j> will overshoot the neutral static equilibrium value and tilt towards the human as shown in FIG. 2B. If no further external force is applied by the human, the roll angle of the body 2 will then return to the neutral static equilibrium angle, optionally after one or more further decaying oscillations.
[0078] From time t_2 of FIG. 2B to time t_3 in FIG. 2C, the human has again pushed the side of the body 2 once the roll angle <j> has reached a maximum value of FIG. 2B, to continue a side-to-side rocking motion of the roll angle <j> of the body 2. By applying the pushing force once the roll angle <j> has reached the maximum value, the pushing force is additional with the reaction force from the suspension, allowing the amplitude of the oscillation to be maintained or even to increase, depending on the magnitude of the pushing force. Depending on the amplitude and timing of the pushing force, as well as the damping of the suspension, the human can continue to rock the body 2 indefinitely or for several seconds, at least.
[0079] FIG. 2D graphically illustrates the sinusoidal roll angle <j> (solid line) and sinusoidal extrinsic force F_4> (dashed line). The amplitude of the oscillation increases for a constant pushing force, assuming that the extrinsic pushing force is applied in-phase with the sinusoidal roll angle. The amplitude of the oscillation may reach a peak dependent on the extrinsic force and suspension characteristics.
[0080] If the suspension is critically damped or overdamped, the roll angle <j> may not overshoot the neutral static equilibrium angle of the body 2, but some rocking is still possible.
[0081] Due to the high mass and stiff suspensions of modern vehicles, it is difficult for one human alone to achieve sufficient back and forth rocking to provide a beneficial effect. Therefore, a high mass vehicle 1 may require multiple people to be available to push against the side of the body 2 of the vehicle 1. Some, but not necessarily all aspects and embodiments of the present invention provide a function for assisting with the rocking, without limitation to high-mass vehicles in particular. The aspects and embodiments may apply to other use cases too.
[0082] An active vehicle suspension 104 and a control system 400 will first be described.
[0083] FIG. 3 illustrates an example implementation of the active vehicle suspension 104.
[0084] The active vehicle suspension 104 comprises front left active suspension 106 for a front left wheel FL, front right active suspension 116 for a front right wheel FR, rear left active suspension 108 for a rear left wheel RL, and rear right active suspension 118 for a rear right wheel RR. The active suspension for each wheel (e.g. quarter / corner) of the vehicle 1 may be individually controllable.
[0085] FIG. 3 also shows a torque source 103 such as an internal combustion engine or electric machine, for driving at least some of the vehicle wheels 3.
[0086] The active suspension for each corner of the vehicle 1 comprises an actuator 302.
[0087] The actuator 302 may be a hydraulic actuator such as a hydraulic fluid-filled chamber containing a piston. One end of the actuator 302 is coupled to a vehicle wheel 3 and the other end is coupled to the vehicle body 2. A spring 304 (e.g. coil or pneumatic) may be in equilibrium and acting in parallel with the actuator 302.
[0088] When the vehicle suspension is undisturbed, the piston of the hydraulic actuator 302 is located at a neutral position in the chamber.
[0089] The piston can move in either direction inside the chamber, for example due to a road disturbance compressing the actuator 302. The piston can displace fluid out of the chamber into a hydraulic circuit (not shown). The fluid imparts a restoring force against movement of the piston. Energy can be added to and / or extracted from the actuator 302 by pumping fluid and / or controlling valves to regulate fluid pressure to either side of the piston.
[0090] Therefore, a control system 400 can dynamically control restoring force against the displaced piston. This force is equivalent to spring force of a coil spring against displacement. Dynamic control enables the force-displacement relationship to be changed to adapt to a driving scenario. Energy can be added or removed quickly, e.g. within tens of milliseconds. In order to control spring force, the control system 400 may output a force request that is dependent on sensed wheel travel (wheel-to-body displacement / articulation).Dynamic damping characteristics of the actuator 302 can be modified by controlling a fluid valve at a constriction, which regulates the rate at which fluid is transferred in and out of the actuator 302 by movement of the piston.
[0091] Furthermore, energy can be added to or removed from the actuator 302 in order to extend or retract the actuator 302. In FIG. 3 this enables the actuator force to be changed independently at different lateral sides, longitudinal ends, and / or corners of the vehicle 1.
[0092] The above example refers to a hydraulic actuator 302, and in other embodiments the actuator 302 may be an electromagnetic actuator or a pneumatic actuator, or the like.
[0093] In FIG. 3 but not necessarily all examples, the spring 304 comprises an active spring such as a pneumatic spring, enabling control of ride height. The control system 400 may be configured to operate a pump to pump gas (e.g. air) in or out of the active spring 304 to control ride height. An air-levelling function of the control system 400 seeks to maintain a set ride height irrespective of vehicle load and achieves this by modifying the volume of air and therefore air pressure to maintain the set ride height.
[0094] Energy can be added to or removed from the active spring 304 in order to increase or decrease the volume of the active spring 304. Increasing the volume can lift the vehicle body 2 in the z-axis. In FIG. 3 this enables the wheel-to-body distance to be changed independently at different lateral sides, longitudinal ends and / or corners of the vehicle 1.
[0095] Additionally, or alternatively, the spring 304 comprises a passive spring (e.g. coil) or is omitted entirely.
[0096] In at least some examples the control system 400 is configured to control the active vehicle suspension 104 by transmitting a force request to the active suspension or to a low-level controller thereof. The force request may be an arbitrated force request based on force requests from various requestors and information from various sensors.
[0097] Control of the active vehicle suspension 104 relies on one or more sensors. FIG. 3 illustrates optional sensors that may interact with the control system 400 to influence a force request calculation. These include any one or more of the following:
[0098] - A wheel speed sensor 312 for each wheel 3. Each wheel speed sensor 312 is for outputting a wheel speed signal indicative of a wheel speed of the wheel 3. In an example implementation, the wheel speed sensor 312 is partofan antilock braking system (ABS).
[0099] - A wheel-to-body displacement sensor 314 for outputting a wheel displacement signal indicative of wheel travel. The wheel-to-body displacement sensor 314 is placed somewhere on the active suspension and can sense the position of the wheel 3 along an arc defined by suspension geometry. An example of a wheel-to-body displacement sensor 314 is a rotary potentiometer attached to a lever, wherein one end of the lever is coupled to the vehicle body 2, and the other end is coupled to a suspension link.
[0100] - A hub-mounted accelerometer 316 for each wheel 3, coupled to the unsprung mass of the vehicle 1. The hub-mounted accelerometer 316 outputs a hub motion signal indicative of a speed and / or acceleration in three degrees of freedom (3DOF) or six degrees of freedom (6DOF), or in at least the vertical z-axis.- A human-machine interface (HMI) 320. This refers to any of the various input devices and input / output devices available to the driver such as touchscreens, displays, hardware switches / sliders / selectors, voice assistants, or the like. The control system 400 receives signals indicative of user inputs from the HMI 320.
[0101] - At least one vehicle body accelerometer 322 coupled to the vehicle body 2 (sprung mass). The vehicle body accelerometer 322 outputs a body motion signal indicative of a speed and / or acceleration of the body 2 in three degrees of freedom (3DOF) or six degrees of freedom (6DOF), or in at least one axis. A unit may comprise an accelerometer or a multi-axis set of accelerometers.
[0102] - A ground speed estimator 324 for outputting ground speed data indicative of the vehicle speed over ground. The ground speed estimator 324 may be implemented in software alone, or in hardware, or a combination thereof. The ground speed estimator 324 is configured to estimate a ground speed of the vehicle 1 in dependence on wheel speed signals from a plurality of the wheel speed sensors 312.
[0103] - A closure state sensor 326 for outputting closure state data indicative of whether a closure of the vehicle 1 is in a closed or open state. A closure may comprise a side door and / or a tailgate, for example.
[0104] With reference to FIG. 4, there is illustrated a control system 400 for a vehicle 1. The control system 400 comprises one or more controllers 401.
[0105] The control system 400 is configured to receive the above-mentioned data from any one or more of the sensors described above 312, 314, 316, 320, 322, 324, 326, and determine a control signal for the active vehicle suspension 104. The control system 400 may then output a control signal such as an actuator control signal to control the actuator 302 and / or a spring control signal to control the active spring 304. The control signal is dependent on the data.
[0106] The control system 400 as illustrated in FIG. 4 comprises one controller 401, although it will be appreciated that this is merely illustrative. The controller 401 comprises processing means 404 and memory means 406. The processing means 404 may be one or more electronic processing device 404 which operably execute computer-readable instructions. The memory means 406 may be one or more memory device 406. The memory means 406 is electrically coupled to the processing means 404. The memory means 406 is configured to store instructions, and the processing means 404 is configured to access the memory means 406 and execute the instructions stored thereon.
[0107] The controller 401 comprises an input means 410 and an output means 412. The input means 410 may comprise an electrical input 410 of the controller 401. The output means 412 may comprise an electrical output 412 of the controller 401. The controller 401 may have an interface 402 comprising an electrical input / output I / O 410, 412, or an electrical input 410, or an electrical output 412, for receiving information and interacting with external components. The input 410 is arranged to receive a signal from any one or more of the sensors described above 312, 314, 316, 320, 322, 324, 326. The output 412 is arranged to output an actuator control signal, indicative of a force request for controlling the actuator 302. Alternatively, or additionally, the output 412 is arranged to output a spring control signal, indicative of a force request for controlling the active spring 304.
[0108] FIG. 5 illustrates a non-transitory computer-readable storage medium 500 comprising the instructions (computer software).
[0109] FIG. 6 illustrates a method 600 according to an embodiment of the invention. The method 600 is a method of controlling an active vehicle suspension 104 of a vehicle 1 , such as the vehicle 1 illustrated in FIG. 1. In particular, but not exclusively,the method 600 is an assisted vehicle rocking method of controlling the actuators 302 of the active vehicle suspension 104 to control a roll, pitch, and / or heave angle of the body 2 of the vehicle 1 , to assist an extrinsic human source of excitation. The method 600 may be performed by the control system 400 illustrated in FIG. 4. In particular, the memory 406 may comprise computer-readable instructions 408 which, when executed by the processor 404, perform the method 600.
[0110] Manual initiation block 602 may be executed first, in an implementation in which initiation of the method 600 can be manually requested. At block 602, the method 600 comprises receiving a user input signal from an HMI 320. The user input signal requests the control system 400 to assist an extrinsic source of excitation in the form of one or more humans intending to rock the body 2 of the vehicle 1 to aid traction of the vehicle 1.
[0111] Blocks 602 and 610 are shown in broken lines because blocks 602 and 610 represent alternative approaches to HMI interaction with a driver. Block 602 represents a manual-initiation implementation, while block 610 is relevant to an automatic-initiation implementation. They are also optional.
[0112] For the manual initiation block 602, the user input signal may be received before the extrinsic source of excitation has begun. Block 602 is therefore a preparatory step.
[0113] In some implementations, the HMI 320 is configured to render a graphical user interface (not shown) comprising an interactive element for requesting the method 600. The interactive element may comprise a button, slider, or equivalents thereof.
[0114] The interactive element may be rendered along a description of a function of the interactive element, indicating that the element controls an assisted vehicle rocking method 600. In some examples, the interactive element may be one of a plurality of interactive elements for different terrain recovery functions, the elements being displayed within a terrain-related menu of the HMI 320.
[0115] In some implementations, a user input signal can be received from a voice assistant HMI 320, indicative that a voice command requests the control system 400 to assist an extrinsic source of excitation.
[0116] These are just some of several potential implementations.
[0117] In response to the user input signal, the control system 400 causes one or more entry conditions to be checked, shown as those shown in one or more of blocks 604, 606, 608, and 612.
[0118] The control system 400 is then configured to initiate outputting a control signal at block 618 to request an in-phase force for assisting the extrinsic source of excitation, once a human located by the vehicle 1 has started the excitation. This is contingent on the one or more entry conditions being satisfied, otherwise the human will not be assisted.
[0119] Block 604 relates to an optional entry condition for determining that the body 2 of the vehicle 1 is being oscillated by an extrinsic human source of excitation. Block 604 is advantageous in implementations where the extrinsic human source of excitation is capable of being automatically detected by the control system 400, with or without the manual user input signal being received first.
[0120] Block 604 comprises receiving a body motion signal indicative of oscillation of the body 2 of the vehicle 1. The body motion signal may be indicative of a roll oscillation of the body 2. In some examples, the body motion signal may be indicative ofa pitch or heave oscillation of the body 2. The body motion signal may be received from the vehicle body accelerometer 322. Alternatively, or additionally, the body motion signal may be determined in dependence on information from the wheel-to-body displacement sensors 314.
[0121] Block 604 comprises determining whether the body motion signal is indicative of an extrinsic source of excitation oscillating the body 2 of the vehicle 1. In some examples, block 604 comprises criteria for determining whether the body motion signal is indicative of a human extrinsic source of excitation oscillating the body 2 of the vehicle 1 to aid traction.
[0122] For example, the condition of block 604 may comprise a criterion for determining whether the source of excitation is extrinsic. An extrinsic source refers to an excitation of the body 2 that is caused by forces other than those requested by the control system 400. The source could be external to the vehicle 1 , such as one or more humans standing next to the vehicle 1 and pushing the body 2. Alternatively, the source could be inside the vehicle 1 , such as one or more humans jumping up and down on a left or right seat. Extrinsic sources also refer to potholes and road undulations in situations where the vehicle 1 is moving. Determining that the source of excitation is extrinsic may be dependent on comparing the body motion signal against the force requests from the requestors of the vehicle 1. The criterion may be satisfied in dependence on determining that the body motion signal is dependent on a force other than already-requested force.
[0123] The condition of block 604 may comprise a criterion for determining whether a frequency of the excitation indicates that the extrinsic source of excitation is approximately resonant with a natural frequency of the active vehicle suspension 104. This would indicate that a human is attempting to rock the body back-and-forth. The criterion may be satisfied in dependence on determining that a frequency of the oscillation, indicated by the body motion signal, is within a frequency range defined by upper and lower bounds such as 1 Hz to 3Hz. The frequency range may filter out natural sources such as wind buffeting or wave-induced motion of a vehicle ferry. The first-order natural frequency of the active vehicle suspension 104 may be within this frequency range.
[0124] The condition of block 604 may comprise a criterion for determining whether an intensity of the excitation has a value associated with a human rocking the body 2. The criterion may be satisfied in dependence on determining that an intensity of the oscillation, indicated by the body motion signal, is greater than a minimum threshold, or is within an intensity range defined by upper and lower bounds. The minimum threshold may filter out natural sources such as wind buffeting. The intensity may be indicative of at least one of a peak amplitude of the oscillation, a peak rate of change of the oscillation such as roll rate, a peak acceleration of the oscillation, or another measure of intensity such as spectral intensity in a frequency domain. An example of a minimum threshold or lower bound for the intensity is a roll rate selected from the range 0.8 deg / sec to 3 deg / sec.
[0125] In some examples, the condition of block 604 comprises a plurality of the criteria. For example, determining that block 604 is satisfied may comprise determining that the above-threshold intensity in the frequency range due to the extrinsic source is greater than an intensity of other frequencies outside the frequency range by at least a threshold amount.
[0126] In some, but not necessarily all examples, the criteria of block 604 are substantially isolated to a roll component of the body motion signal. Pitch, heave, and yaw components of the oscillation may be ignored. In some examples, a further criterion may require pitch oscillation to be less than a threshold pitch component in order for the method 600 to progress. The threshold pitch component may be an absolute value, or may be relative to the roll component to ensure that the roll component is greater than the pitch component. This is because the method 600 may require a human rocking the vehicle 1 to be stood next to the left or right side of the vehicle, rather than rocking the vehicle 1 from in front of or behind the vehicle 1. In other examples, the criteria of block 604 may be based on a combination of one or more of roll, pitch, orheave. For example, if the method 600 can accommodate a person inside the vehicle 1 jumping up and down on their seat, this may induce pitch, heave, and / or roll depending on where they are in the vehicle 1 , and the resultant angle may be taken into account.
[0127] In some examples, block 604 comprises a consistency criterion requiring one or more of the above-described criteria to be consistent over a predetermined time period such as 2 to 5 seconds.
[0128] The method 600 progresses towards assisted vehicle rocking (blocks 616 and 618) in dependence on the condition of block 604 being satisfied. However, further optional entry conditions are shown before assisted vehicle rocking can commence. The method 600 may terminate at block 626 or loop back to before block 604 in dependence on the condition of block 606 being unsatisfied.
[0129] Block 606 comprises an optional condition to verify that the speed of the vehicle 1 is below a threshold. This is advantageous in implementations where the extrinsic source of excitation is capable of being automatically detected by the control system 400, as well as implementations in which the manual user input signal is received first.
[0130] The condition of block 606 may comprise determining that longitudinal speed of the vehicle 1 is below a threshold. Block 606 comprises receiving a speed signal indicative of a vehicle speed of the vehicle 1. The speed signal may be received from the ground speed estimator 324. The speed signal may therefore be indicative of vehicle speed over ground, which itself may differ from individual wheel speeds.
[0131] The condition may comprise determining whether the vehicle speed is zero or less than a threshold. The threshold may be a value indicative of a substantially zero vehicle speed, such as a value selected from the range 0 to 0.8 metres per second. The criterion is satisfied in dependence on the vehicle speed being zero or less than the threshold.
[0132] For implementations where the extrinsic source of excitation is capable of being automatically detected by the control system 400 without the initial manual initiation block 602, the condition of block 606 may comprise a criterion for determining whether propulsive torque is being requested while the speed is below the threshold. This helps to confirm that the vehicle is ‘stuck’ rather than intentionally parked. The criterion may be satisfied in dependence on determining that a propulsive torque request is greater than a threshold, in dependence on information received from an accelerator pedal module or autonomous driving module. The propulsive torque request is for controlling the torque source 103 to drive the vehicle 1 forwards or in reverse.
[0133] In some examples, the condition of block 606 comprises a plurality of the criteria. For example, determining that block 606 is satisfied may comprise determining that the vehicle speed is zero or less than a threshold while the propulsive torque request is greater than a threshold.
[0134] The method 600 progresses towards assisted vehicle rocking (blocks 616 and 618) in dependence on the condition of block 606 being satisfied. However, further optional entry conditions are shown before assisted vehicle rocking can commence. The method 600 may terminate at block 626 or loop back to before block 606 in dependence on the condition of block 606 being unsatisfied.
[0135] Block 608 comprises an optional condition to determine whether assisted vehicle rocking will result in an angle of the vehicle body 2 being within acceptable limits of a horizontal horizon. This is advantageous in implementations where the vehicle 1 is on a steep slope, where assisted vehicle rocking may be undesirable.Block 608 may comprise a criterion for determining whether a slope angle of the vehicle 1 is within a limit. Block 608 comprises receiving a body angle signal indicative of a static angle or static roll angle of the body 2 of the vehicle 1 , indicative of a slope angle of terrain beneath the vehicle 1. The body angle signal may be received from the vehicle body accelerometer 322 and / or from the hub-mounted accelerometers 316. If the body 2 is currently being rocked, the control system 400 may calculate an average to ignore the oscillations.
[0136] The criterion for determining whether the slope angle of the vehicle 1 is within a limit may comprise determining whether the slope angle of the vehicle 1 is within the limit, wherein the criterion is satisfied in dependence on the slope angle being within the limit. The limit may comprise a slope angle selected from the range -10 to +10 or -5 to +5 degrees in roll.
[0137] The method 600 progresses towards assisted vehicle rocking (blocks 616 and 618) in dependence on the condition of block 608 being satisfied. However, one or more further optional entry conditions are shown before assisted vehicle rocking can commence. The method 600 may terminate at block 626 or loop back to before block 608 in dependence on the condition of block 608 being unsatisfied.
[0138] User-confirmation block 610 relates to an implementation in which the extrinsic human source of excitation and the stuck state of the vehicle 1 are automatically detected by the control system 400 by one or more of the entry conditions, without a prior manual request (block 602 omitted). This is used to secure a confirmation from the driver of the vehicle 1 to permit assisted vehicle rocking.
[0139] At block 610, the control system 400 may control the HMI 320 to output a request that suggests the method 600 (assisted vehicle recovery), either directly or indirectly (“are you stuck?”). If other terrain recovery methods are also available, the request may not be limited to the presently-described method 600 but may instead be for navigating the user to a GUI for accessing a suite of terrain recovery functions including the presently-described method 600. The request may suggest or direct the user to one or more interactive elements as described earlier, including one for activating the method 600. In some examples, the request may be rendered as audio and / or may suggest that the user issues a voice command as described earlier.
[0140] However the request is implemented, the general effect of the request is to seek user authorisation (such as manual input) to permit or cause initiation of the method 600. The request may be regarded as a prompt and part of the entry conditions. This check may be performed at various times within the flowchart, not limited to the time shown. There would be at least one automatic entry condition prior to block 610, and assisted vehicle rocking would start afterwards.
[0141] At block 610, the method 600 comprises receiving a user input signal from the HMI 320, in response to the request, the user input signal permitting the control system 400 to assist the extrinsic human source of excitation.
[0142] The method 600 progresses towards assisted vehicle rocking (blocks 616 and 618) in dependence on the condition (user input signal) of block 610 being satisfied. However, a further optional entry condition is shown before assisted vehicle rocking can commence. The method 600 may terminate at block 626 or loop back to before block 610 in dependence on the condition of block 610 being unsatisfied (no user input signal received, or a denial signal is received).
[0143] Block 612 comprises an optional entry condition to determine whether closures (e.g., doors) of the vehicle 1 are in a closed state, to ensure that humans are either securely inside or outside the vehicle 1 and also to reduce the chance of contactbetween an open closure and an object. This is because the vehicle 1 may gain traction and lurch in one direction, or may lose traction and slip in another direction.
[0144] Block 612 may comprise a criterion for determining whether the closures are in a closed state. Block 612 comprises receiving closure state signals from closure state sensors 326, indicative of an open or closed state or position of each one of a plurality of closures of the vehicle 1. One or more side door closure state signals may indicate the state or position of each one of a plurality of side doors of the vehicle 1. A tailgate closure state signal may indicate the state or position of a tailgate of the vehicle 1. Satisfaction of the criterion may comprise determining that the closures are in a closed state.
[0145] The method 600 progresses towards assisted vehicle rocking (blocks 616 and 618) in dependence on the condition of block 612 being satisfied. The method 600 may terminate at block 626 or loop back to before block 612 in dependence on the condition of block 612 being unsatisfied.
[0146] This check may be performed at various times within the flowchart, prior to assisted vehicle rocking starting (block 616).
[0147] The method 600 is now ready to commence assisted vehicle rocking. The control system 400 may send a confirmation signal controlling an HMI 320 to render an acknowledgement or status message that the control system 400 is in a state for assisting the extrinsic source of excitation. If human rocking has not yet started, the confirmation signal may include an advance instruction requesting that a human occupant positions themselves next to the vehicle 1 and starts rocking the vehicle 1. The advance instruction may be rendered at a non-specific time in the flowchart, before assisted vehicle rocking has commenced.
[0148] The next block 616 is executed while the body 2 of the vehicle 1 is being oscillated by the extrinsic human source of excitation. At block 616, the method 600 comprises determining an in-phase force for the active vehicle suspension 104, in dependence on the body motion signal from the vehicle body accelerometer 322, to assist the extrinsic human source of excitation in maintaining or amplifying the oscillation of the body 2 of the vehicle 1.
[0149] If the extrinsic source of excitation induces roll, the in-phase force may comprise a requested vehicle roll force to assist the human-induced roll oscillation indicated by the body motion signal. The requested in-phase roll force comprises individual force requests to the actuators 302, so that the left and right actuators 302 collectively continue the roll oscillation.
[0150] If the extrinsic source of excitation induces pitch and / or heave, the in-phase force may comprise a requested pitch force and / or a requested heave force.
[0151] Specifically, an in-phase roll force comprises, for each oscillation:
[0152] - over a first time period, requesting simultaneous extension of the actuators 302 for the front left and rear left wheels FL, RL and / or requesting simultaneous retraction of the actuators 302 for the front right and rear right wheels FR, RR; and - over a second subsequent time period, requesting simultaneous extension of the actuators 302 for the front right and rear right wheels FR, RR and / or requesting simultaneous retraction of the actuators 302 for the front left and rear left wheels FL, RL.
[0153] The in-phase roll force is determined such that the first and second time periods are in-phase with the human-induced roll oscillation.Determining the in-phase force may comprise monitoring the body motion signal over a predetermined time period, and determining a timing of the in-phase force in dependence on the body motion signal over the predetermined time period, to assist the extrinsic source of excitation in oscillating the body 2 of the vehicle 1. The timing may comprise determining a frequency and phase of the in-phase force to substantially match a frequency and phase of the oscillation from the extrinsic human source of excitation. The timing may comprise a frequency selected from the range 1 Hz to 3Hz, similar to the frequency range described above.
[0154] Determining the in-phase force may further comprise determining an amplitude of the in-phase force. In some examples, the amplitude is an open-loop, predetermined amplitude such as an oscillating ±XkN or periodic 0 to +XkN force request, where X depends on the implementation. In other words, the force may either switch polarity (±) such that oscillating rocking force is applied in both clockwise and anticlockwise directions, or may be only one polarity (0 to +XkN) such that in-phase periodic rocking force is applied in either a clockwise or anticlockwise rocking direction. This open loop approach is advantageous for reducing the minimum effort required by the human rocking the vehicle 1, while allowing the human to supply the extra effort needed to produce the desired rocking amplitude. The control system 400 may not even need to monitor the user’s frequency for changes, because it is assumed that the user and control system 400 will both target the same resonant frequency.
[0155] In some examples, the amplitude is a feedback-dependent closed-loop value, dependent on feedback such as an amplitude of the body motion signal, or amplitude and frequency. This can be used to match or increase the amplitude of the oscillation, or to provide a proportion of the oscillation dependent on how much force the human is applying. For example, the active vehicle suspension 104 may contribute 50% to <100% of the force for maintaining the monitored human-induced amplitude of the oscillation, so that the human has greater control of the oscillation by increasing or decreasing the human component of the force. This also means that the actuators 302 will allow the body 2 to come to a rest if the human stops applying force.
[0156] Block 618 comprises outputting a control signal to the active vehicle suspension 104, requesting the in-phase force. The control signal can comprise individual force requests sent to the actuators 302, so that the left and right actuators 302 collectively continue the oscillation. In some examples, if the active springs 304 are capable of controlling ride height at a frequency similar to the human-induced oscillation, the control signal can comprise oscillation requests sent to the active springs 304.
[0157] In some examples, if the active vehicle suspension 104 is stiff (overdamped or critically damped), the individual force requests may also reduce a stiffness of the actuators 302 and / or active springs 304 relative to a default value. The control system 400 may determine target values or offsets for the individual force requests to reduce the natural frequency. This is applicable to control signals sent to the actuators 302 and / or active springs 304. The target values or offsets are configured to tune a natural frequency of the active vehicle suspension 104 to a frequency of the oscillation to facilitate human-induced resonance. The natural frequency may be tuned to a detected frequency of the human-induced oscillation, or the natural frequency may be tuned to a value within the frequency range of block 604 without knowing the actual frequency.
[0158] Block 620 comprises an exit condition comprising one or more criteria. In some examples, a criterion of the exit condition comprises an expiry of a timer. The timer is shown at block 622. The timer may start in dependence on initiation of the assisted vehicle rocking at block 618 or earlier. The exit condition may comprise an expiry time selected from the range 3 to 30 seconds or 3 to 10 seconds, for example.Expiry of the timer may either terminate the method 600 at block 626, or loop back to the entry conditions (block A) to check that one or more of the entry conditions are still satisfied. Provision of the in-phase force may be inhibited while one or more of the entry conditions are being checked again. This is useful if the control system 400 is unable to ascertain whether the human is still applying effort for rocking the vehicle 1, while the in-phase force is being applied. Therefore, a momentary pause of in-phase force upon timer expiry allows the control system 400 to determine whether at least one human is still rocking the vehicle 1 to increase traction.
[0159] In some examples, the ‘nth’ expiry of the timer may terminate the method 600 at block 626, after at least one loop back.
[0160] Block 626 is a termination block for inhibiting provision of the in-phase force. This can comprise terminating the in-phase force if it is ongoing, or not initiating the in-phase force provision if it is not ongoing. Block 626 is executed in dependence on at least one of the above entry conditions being unsatisfied, and / or satisfaction of an exit condition.
[0161] In summary, criteria for inhibiting provision of the in-phase force can comprise one or more of:
[0162] - intensity below-threshold or outside limits;
[0163] - frequency outside limits;
[0164] - pitch component above a threshold pitch component;
[0165] - vehicle speed above threshold;
[0166] - requested propulsive torque below threshold;
[0167] - slope angle outside limit;
[0168] - no user input signal received, or user denial signal received;
[0169] - closure in an open state;
[0170] - HMI request to cease operation;
[0171] - brake pedal depression; or
[0172] - timer expired (block 620).
[0173] 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. For example, in some implementations the assisted vehicle rocking may allow a pitch component and / or heave component, or may be substantially in a pitch axis rather than a roll axis.
[0174] It is to be understood that the or each controller 401 can comprise a control unit or computational device having one or more electronic processors (e.g., a microprocessor, a microcontroller, an application specific integrated circuit (ASIC), etc.), and may comprise a single control unit or computational device, or alternatively different functions of the or each controller 401 may be embodied in, or hosted in, different control units or computational devices. As used herein, the term “controller,” “control unit,” or “computational device” will be understood to include a single controller, control unit, or computational device, and a plurality of controllers, control units, or computational devices collectively operating to provide the required control functionality. A set of instructions could be provided which, when executed, cause the controller 401 to implement the control techniques described herein (including some or all of the functionality required for the method(s) described herein). The set of instructions 408 could be embedded in said one or more electronic processors 404 of the controller 401 ; or alternatively, the set of instructions 408 could be provided as software to be executed in the controller 401. A first controller or control unit may be implemented in software run on one or more processors. One or more other controllers or control units may be implemented in software run on one or more processors, optionally the same one or more processors as the first controller or control unit. Other arrangements are also useful.The, or each, electronic processor 404 may comprise any suitable electronic processor (e.g., a microprocessor, a microcontroller, an ASIC, etc.) that is configured to execute electronic instructions 408. The, or each, electronic memory device 406 may comprise any suitable memory device and may store a variety of data, information, threshold value(s), lookup tables or other data structures, and / or instructions therein or thereon. In an embodiment, the memory device 406 has information and instructions for software, firmware, programs, algorithms, scripts, applications, etc. stored therein or thereon that may govern all or part of the methodology described herein. The processor, or each, electronic processor 404 may access the memory device 406 and execute and / or use that or those instructions and information to carry out or perform some or all of the functionality and methodology described herein.
[0175] The at least one memory device 406 may comprise a computer-readable storage medium (e.g. a non-transitory or nontransient storage medium) that may comprise any mechanism for storing information in a form readable by a machine or electronic processors / computational devices. Examples of the form include, without limitation: a magnetic storage medium (e.g. floppy diskette); optical storage medium (e.g. CD-ROM); magneto optical storage medium; read only memory (ROM); random access memory (RAM); erasable programmable memory (e.g. EPROM and EEPROM); flash memory; or electrical or other types of medium for storing such information / instructions.
[0176] It will be appreciated that embodiments of the present invention can be realised in any suitable form of hardware, software or a combination of hardware and software. For example, it is contemplated that the present invention is not limited to being implemented by way of programmable processing devices, and that at least some of, and in some embodiments all of, the functionality and or method steps of the present invention may equally be implemented by way of non-programmable hardware, such as by way of non-programmable ASIC, Boolean logic circuitry, etc.
[0177] The blocks illustrated in FIG. 6 may represent steps in a method and / or sections of code in the computer program 408. The illustration of a particular order to the blocks does not necessarily imply that there is a required or preferred order for the blocks and the order and arrangement of the block may be varied. Furthermore, it may be possible for some steps to be omitted.
[0178] Features described in the preceding description may be used in combinations other than the combinations explicitly described. Although functions have been described with reference to certain features, those functions may be performable by other features whether described or not. Although features have been described with reference to certain embodiments, those features may also be present in other embodiments whether described or not.
Claims
CLAIMS1. A control system for an active vehicle suspension of a vehicle, the control system comprising one or more processors collectively configured to:receive a body motion signal indicative of oscillation of a body of the vehicle;determine an in-phase force for the active vehicle suspension, in dependence on the body motion signal, to assist an extrinsic source of excitation in oscillating the body of the vehicle; andoutput a control signal to the active vehicle suspension, requesting the in-phase force.
2. The control system of claim 1 , the one or more processors collectively configured to:receive a speed signal indicative of a vehicle speed of the vehicle;determine that the vehicle speed is zero or less than a threshold; andinitiate outputting the control signal requesting the in-phase force, at least in dependence on the vehicle speed being zero or less than the threshold.
3. The control system of claim 1 or 2, the one or more processors collectively configured to:receive a user input signal from a human-machine interface, the user input signal requesting or permitting the control system to assist the extrinsic source of excitation; andinitiate outputting the control signal requesting the in-phase force, at least in dependence on receiving the user input signal.
4. The control system of claim 1 , 2, or 3, the one or more processors collectively configured to:determine that the oscillation of the body of the vehicle has an intensity greater than a minimum threshold; and initiate outputting the control signal requesting the in-phase force, at least in dependence on the oscillation having an intensity greater than the minimum threshold.
5. The control system of any preceding claim, the one or more processors collectively configured to:determine that a slope angle of the vehicle is within a limit; andinitiate outputting the control signal requesting the in-phase force, at least in dependence on the slope angle of the vehicle being within the limit.
6. The control system of any preceding claim, the one or more processors collectively configured to:determine that closures of the vehicle are in a closed state; andinitiate outputting the control signal requesting the in-phase force, at least in dependence on the closures being in the closed state.
7. The control system of any preceding claim, wherein the oscillation indicated by the body motion signal comprises roll oscillation, and wherein the in-phase force comprises a vehicle roll force.
8. The control system of any preceding claim, the one or more processors collectively configured to:inhibit provision of the in-phase force, in dependence on the body motion signal comprising an above-threshold pitch component.
9. The control system of any preceding claim, wherein the in-phase force comprises a predetermined amplitude.
10. The control system of any one of claims 1 to 8, wherein an amplitude of the in-phase force is dependent on an amplitude of the body motion signal.
11. The control system of any preceding claim, the one or more processors collectively configured to:inhibit requesting the in-phase force in dependence on a predetermined time period elapsing, the predetermined time period having a duration selected from the range 3 to 30 seconds after initiation of requesting the in-phase force.
12. A system comprising the control system of any preceding claim, and the active vehicle suspension.
13. A vehicle comprising the control system of any one of claims 1 to 11 , or the system of claim 12.
14. A method of controlling an active vehicle suspension of a vehicle, the method comprising:receiving a body motion signal indicative of oscillation of a body of the vehicle;determining an in-phase force for the active vehicle suspension, in dependence on the body motion signal, to assist an extrinsic source of excitation in oscillating the body of the vehicle; andoutputting a control signal to the active vehicle suspension, requesting the in-phase force.
15. Computer readable instructions which, when executed by a computer, are arranged to perform a method according to claim 14.