Dynamic grip control for a vehicle

Abstract

A computer-implemented method for dynamic grip control of a vehicle is disclosed. The vehicle comprises motion support devices for actuating the vehicle and a control allocator for transforming motion requests to actuator instructions, and is configured to respond to the motion requests by operating the motion support devices in response to the actuator instructions. The motion support devices include one or more individually controllable suspension actuators configured to cause dynamic distribution of vertical force among suspension points of the vehicle. The method comprises applying constraints on lateral and / or longitudinal forces when transforming the motion requests to the actuator instructions, wherein respective lateral and / or longitudinal forces are associated with respective suspension points, and wherein the constraints on lateral and / or longitudinal forces are dynamically varying in dependence on the dynamic distribution of vertical force. Corresponding computer system, vehicle, computer program product, and non- transitory computer-readable storage medium are also disclosed.

Description

DYNAMIC GRIP CONTROL FOR A VEHICLETECHNICAL FIELD

[0001] The disclosure relates generally to vehicle control. In particular aspects, the disclosure relates to dynamic grip control for a vehicle. The disclosure can be applied to heavy-duty vehicles, such as trucks, buses, and construction equipment, among other vehicle types. Although the disclosure may be described with respect to a particular vehicle, the disclosure is not restricted to any particular vehicle.BACKGROUND

[0002] Generally, the field of vehicle motion control includes various tasks. When the vehicle comprises a plurality of motion support devices for actuating the vehicle, one example task is transformation of motion requests to actuator instructions. Such transformation may typically include allocation of lateral and / or longitudinal forces based on the motion requests. To ensure proper grip, the allocation of lateral and / or longitudinal forces is typically subject to an assumed friction situation.

[0003] A problem with existing approaches for allocation of lateral and / or longitudinal forces is that they may lead to improper allocation. Improper allocation of lateral and / or longitudinal forces may cause unsafe vehicle behavior (e.g., lost grip for one or more wheels). Alternatively or additionally, improper allocation of lateral and / or longitudinal forces may fail to utilize the full motion potential of the vehicle (e.g., by applying overly restrictive limitations for the lateral and / or longitudinal forces).

[0004] Therefore, there is a need for alternative approaches to force allocation for a vehicle.SUMMARY

[0005] Various aspects may aim to solve, mitigate, alleviate, or eliminate at least some of the above or other disadvantages.

[0006] According to a first aspect of the disclosure, a computer system is provided for dynamic grip control of a vehicle. The vehicle comprises a plurality of motion support devices for actuating the vehicle and a control allocator configured to transform motionrequests to actuator instructions. The motion support devices include one or more individually controllable suspension actuators configured to cause dynamic distribution of vertical force among suspension points of the vehicle. The vehicle is configured to respond to the motion requests by operating the plurality of motion support devices - including the one or more individually controllable suspension actuators - in response to the actuator instructions from the control allocator. The computer system comprises processing circuitry configured to apply constraints on lateral and / or longitudinal forces during transformation of the motion requests to the actuator instructions, wherein respective lateral and / or longitudinal forces are associated with respective suspension points, and wherein the constraints on lateral and / or longitudinal forces are dynamically varying in dependence on the dynamic distribution of vertical force. The first aspect of the disclosure may seek to provide an arrangement for improving the grip control of the vehicle. A technical benefit may include increased flexibility of the limitations for the lateral and / or longitudinal forces, leading to more dynamic allocation of lateral and / or longitudinal forces, which allows increased possibilities to utilize the full motion potential of the vehicle while ensuring safe vehicle behavior.

[0007] According to a second aspect of the disclosure, a computer-implemented method is provided for dynamic grip control of a vehicle. The vehicle comprises a plurality of motion support devices for actuating the vehicle and a control allocator for transforming motion requests to actuator instructions. The motion support devices include one or more individually controllable suspension actuators configured to cause dynamic distribution of vertical force among suspension points of the vehicle. The vehicle is configured to respond to the motion requests by operating the plurality of motion support devices - including the one or more individually controllable suspension actuators - in response to the actuator instructions from the control allocator. The method comprises applying (by a processor device of a computer system) constraints on lateral and / or longitudinal forces when transforming the motion requests to the actuator instructions, wherein respective lateral and / or longitudinal forces are associated with respective suspension points, and wherein the constraints on lateral and / or longitudinal forces are dynamically varying in dependence on the dynamic distribution of vertical force. The second aspect of the disclosure may seek to improve the grip control of the vehicle. A technical benefit may include increased flexibility of the limitations for the lateral and / or longitudinal forces, leading to more dynamicallocation of lateral and / or longitudinal forces, which allows increased possibilities to utilize the full motion potential of the vehicle while ensuring safe vehicle behavior.

[0008] Optionally in some examples, including in at least one preferred example, the dynamic distribution of vertical force may be expressed via vertical force variables in a control allocation problem applied to transform the motion requests to the actuator instructions. A technical benefit may include that the distribution of vertical force is determined jointly with the allocation of lateral and / or longitudinal forces, thereby simplifying the search for an allocation combination that is close to optimal.

[0009] Optionally in some examples, including in at least one preferred example, the control allocation problem may comprise a component that represents a cost of operating the suspension actuators. A technical benefit may include that other aspects than the possible boundaries of safe vehicle operation may be taken into account in the control allocation; e.g., energy consumption variations of the actuators, etc.

[0010] Optionally in some examples, including in at least one preferred example, the dynamic distribution of vertical force may be used (when transforming the motion requests to the actuator instructions) to counteract a variation of external friction conditions among wheels of the vehicle. A technical benefit may include that the respective vertical forces can be set to mitigate problems in low friction scenarios. For example, when a wheel experiences relatively slippery conditions, the vertical force may be increased for the suspension point associated with that wheel to enable grip to be achieved, or the vertical force may be decreased for the suspension point associated with that wheel (e.g., if grip cannot be achieved even with increased vertical force) to enable increased grip to be achieved for other wheels.

[0011] Optionally in some examples, including in at least one preferred example, the dynamic distribution of vertical force may be used (when transforming the motion requests to the actuator instructions) to enable allocation of lateral and / or longitudinal forces as required for accomplishing a vehicle manoeuver indicated by the motion requests. A technical benefit may include improved maneuverability of the vehicle. For example, when the vehicle negotiates a curve, the vertical force may be increased for suspension point(s) associated with the wheels at the inner side of the curve and decreased for suspension point(s) associated with the wheels at the outer side of the curve (e.g., to counteract vehicle roll).

[0012] Optionally in some examples, including in at least one preferred example, the method may further comprise applying (by the processor device) a rollover avoidanceconstraint when transforming the motion requests to the actuator instructions, wherein the rollover avoidance constraint limits the dynamic distribution of vertical force. A technical benefit may include safer vehicle behavior without sacrificing portions of the motion potential of the vehicle.

[0013] Optionally in some examples, including in at least one preferred example, the method may further comprise applying (by the processor device) a tire load constraint when transforming the motion requests to the actuator instructions, wherein the tire load constraint limits the dynamic distribution of vertical force. A technical benefit may include decreased tire wear and / or decreased risk of tire failure.

[0014] Optionally in some examples, including in at least one preferred example, the method may further comprise predicting (by the processor device) upcoming motion requests, and causing (by the processor device) the control allocator to transform the predicted motion requests to actuator instructions for proactive operation of the suspension actuators. A technical benefit may include that the distribution of vertical force can be dynamically adjusted in a proactive manner.

[0015] According to a third aspect of the disclosure, a vehicle is provided comprising the computer system of the first aspect and / or a processor device configured to perform the method of the second aspect. The third aspect of the disclosure may seek to provide a vehicle with improved grip control. A technical benefit may include increased possibilities to utilize the full motion potential of the vehicle while ensuring safe vehicle behavior.

[0016] Optionally in some examples, including in at least one preferred example, the vehicle may further comprise a plurality of motion support devices configured to actuate the vehicle and a control allocator configured to transform motion requests to actuator instructions, wherein the motion support devices include one or more individually controllable suspension actuators configured to cause dynamic distribution of vertical force among suspension points of the vehicle, and wherein the vehicle is configured to respond to the motion requests by operating the plurality of motion support devices, including the one or more individually controllable suspension actuators, in response to the actuator instructions from the control allocator.

[0017] According to a fourth aspect of the disclosure, a computer program product is provided, which comprises program code for performing, when executed by the processing circuitry, the method of the second aspect. The fourth aspect of the disclosure may seek toconvey program code for improving the grip control of a vehicle. A technical benefit may include that new vehicles and / or legacy vehicles may be conveniently configured, by software installation / update, to apply constraints on lateral and / or longitudinal forces when transforming the motion requests to the actuator instructions, wherein respective lateral and / or longitudinal forces are associated with respective suspension points, and wherein the constraints on lateral and / or longitudinal forces are dynamically varying in dependence on the dynamic distribution of vertical force.

[0018] According to a fifth aspect of the disclosure, a non-transitory computer-readable storage medium is provided. The non-transitory computer-readable storage medium comprises instructions, which when executed by the processing circuitry, cause the processing circuitry to perform the method the second aspect. The fifth aspect of the disclosure may seek to convey program code for improving the grip control of a vehicle. A technical benefit may include that new vehicles and / or legacy vehicles may be conveniently configured, by software installation / update, to apply constraints on lateral and / or longitudinal forces when transforming the motion requests to the actuator instructions, wherein respective lateral and / or longitudinal forces are associated with respective suspension points, and wherein the constraints on lateral and / or longitudinal forces are dynamically varying in dependence on the dynamic distribution of vertical force.

[0019] The disclosed aspects, examples (including any preferred examples), and / or accompanying claims may be suitably combined with each other as would be apparent to anyone of ordinary skill in the art. Additional features and advantages are disclosed in the following description, claims, and drawings, and in part will be readily apparent therefrom to those skilled in the art or recognized by practicing the disclosure as described herein.

[0020] There are also disclosed herein computer systems, control units, code modules, computer-implemented methods, computer readable media, and computer program products associated with the above discussed technical benefits.BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Examples are described in more detail below with reference to the appended drawings.

[0022] FIG. 1 is a flowchart illustrating a method according to some examples.

[0023] FIG. 2 is a schematic drawing illustrating a side view of a vehicle according to some examples.

[0024] FIG. 3 is a schematic block diagram illustrating actuation control according to some examples.

[0025] FIG. 4 is a schematic drawing illustrating a bottom view of a vehicle according to some examples.

[0026] FIG. 5 is a schematic diagram illustrating value regions of lateral and longitudinal forces according to some examples.

[0027] FIG. 6 is a schematic drawing illustrating a rear view of a vehicle according to some examples.

[0028] FIG. 7 is a schematic diagram illustrating a computer system for implementing examples disclosed herein, according to some examples.

[0029] FIG. 8 is a schematic drawing illustrating a computer program product, in the form of a non-transitory computer-readable storage medium, according to some examples.

[0030] FIG. 9 is a schematic block diagram of a control unit according to some examples.DETAILED DESCRIPTION

[0031] The detailed description set forth below provides information and examples of the disclosed technology with sufficient detail to enable those skilled in the art to practice the disclosure.

[0032] When a vehicle comprises a plurality of motion support devices (actuators) for actuating the vehicle, one example vehicle motion control task is transformation of motion requests to actuator instructions. Such transformation may include allocation of lateral and / or longitudinal forces based on the motion requests, which is typically subject to an assumed friction situation.

[0033] A problem with existing approaches for allocation of lateral and / or longitudinal forces is that they may lead to improper allocation (e.g., causing unsafe vehicle behavior, failing to utilize the full motion potential of the vehicle, or being otherwise sub-optimal).

[0034] It is suggested to improve existing approaches for transformation of motion requests to actuator instructions by using individually controllable suspension actuators configured to cause dynamic distribution of vertical force (i.e., load distribution) amongsuspension points of the vehicle, and determining the dynamic vertical force distribution jointly with the transformation of motion requests to actuator instructions.

[0035] Thereby, the grip control (and / or other vehicle motion control aspects) may be improved.

[0036] For example, the limitations for the lateral and / or longitudinal forces (which is subject to the assumed friction situation), may be flexibly varied among the wheels of the vehicle via the dynamic distribution of vertical force. Possibilities arising therefrom includes counteraction of a variation of external friction conditions among wheels of the vehicle, and / or enabling an increase of allowable values for the lateral and / or longitudinal forces for some wheel(s) when needed (e.g., for a specific maneuver and / or for safety reasons).

[0037] Generally, the limitations (or constraints) for the lateral and / or longitudinal forces may include any suitable limitation (e.g., so called friction circles, friction ellipses, or approximations thereof).

[0038] In some examples, the dynamic distribution of vertical force enables uniform limitations for the lateral and / or longitudinal forces among two or more wheels even when the friction situation of the ground surface differs among the two or more wheels. For example, when a wheel experiences relatively slippery conditions, the vertical force may be increased for the suspension point associated with that wheel to enable grip to be achieved (e.g., by increasing the radius of a corresponding friction circle). Thus, problems in low friction scenarios may be mitigated.

[0039] In some examples, the dynamic distribution of vertical force enables non-uniform limitations for the lateral and / or longitudinal forces among two or more wheels (e.g., when the friction situation of the ground surface differs substantially among the two or more wheels). For example, when a wheel experiences very slippery conditions such that no grip can be achieved, the vertical force may be decreased for the suspension point associated with that wheel to enable better grip to be achieved for the other wheel(s) (e.g., by increasing the radius of friction circle(s) of the other wheel(s)). Thus, problems in low friction scenarios may be mitigated.

[0040] In some examples, the dynamic distribution of vertical force enables non-uniform limitations for the lateral and / or longitudinal forces among two or more wheels (e.g., when there is a need for unusually large lateral and / or longitudinal forces values for some wheel(s) for some reason, such as negotiating a curvature, avoiding unsafe situations, etc.). Forexample, when the vehicle negotiates a curve, the vertical force may be increased for suspension point(s) associated with the wheels at the inner side of the curve and decreased for suspension point(s) associated with the wheels at the outer side of the curve. Thus, maneuverability of the vehicle may be improved.

[0041] In some examples, an approach is suggested where individually controllable suspension actuators are utilized to provide dynamic grip control.

[0042] The individual vertical forces controlled by the suspension actuators may be included as variables in the control allocation problem, which may be applied by a vehicle motion management (VMM) function. For example, a term for the suspension actuators may be introduced in a cost function of the control allocation problem. Alternatively or additionally, the individual vertical forces controlled by the suspension actuators may be introduced as variables in one or more constraints of the control allocation problem.

[0043] The individual vertical forces controlled by the suspension actuators may be used as variables in the constraints defining friction limits for longitudinal and lateral forces. Thereby, the friction constraints (e.g., friction circle radius) of each wheel may be individually varied by dynamic distribution of the total load among the wheels. For example, the load may be reduced for a wheel with a high friction coefficient to enable the load to be increased for a wheel with low friction coefficient (e.g., so that the friction circle radii become similar for the wheels).

[0044] Thus, according to some examples, controllable load distribution is included in a control allocation problem. The individual vertical forces controlled by the suspension actuators can be used as variables in the constraints defining friction limits for longitudinal and / or lateral forces to provide dynamic grip control.

[0045] It should be noted that a distribution of vertical force may include lifting one or more wheels (i.e., allocating zero vertical force to those wheel(s)). In some examples, a threshold for minimum load is applied to one or more of the wheels of a vehicle to hinder the wheel(s) from being lifted by the suspension actuation.

[0046] FIG. 1 illustrates a method 100 according to some examples. The method is a computer-implemented method for dynamic grip control of a vehicle, wherein the vehicle comprises a plurality of motion support devices for actuating the vehicle and a control allocator for transforming motion requests to actuator instructions.

[0047] The method 100 is performed by a processor device of a computer system. The processor device configured to perform the method 100 may comprise the control allocator, the control allocator may comprise the processor device configured to perform the method 100, or the processor device configured to perform the method 100 and the control allocator may be implemented as separate, but operatively connected, units.

[0048] The motion support devices include one or more (e.g., two or more) individually controllable suspension actuators configured to cause dynamic distribution of vertical force among suspension points of the vehicle. Generally, the suspension points with individually controllable vertical force may be distributed in any suitable way. For example, suspension control may be possible at one or more of: wheel level (for all, or some of the wheels of the vehicle), wheel axle level, wheel pair level (e.g., for a pair of wheels on a same side of the vehicle), or another wheel grouping level.

[0049] Generally, there may be any suitable number of individually controllable suspension actuators. For example, there may be a single individually controllable suspension actuator, two or more individually controllable suspension actuators, one individually controllable suspension actuator per wheel of the vehicle, one individually controllable suspension actuator per wheel in a subset of wheels of the vehicle, one individually controllable suspension actuator per wheel axle of the vehicle, etc.

[0050] An individually controllable suspension actuator may be configured to control the suspension at a single corresponding suspension point, or at two or more corresponding suspension points.

[0051] It should be noted that a single individually controllable suspension actuator configured to control the suspension at a single corresponding suspension point may very well be seen as configured to cause dynamic distribution of vertical force among two or more suspension points of the vehicle. Adjusting the suspension at one suspension point to increase or decrease the vertical load at that suspension point typically leads to a change of vertical load for at least one other suspension point as well (regardless of whether that at least one other suspension point has individually controllable suspension). For example, a wheel axle could have one suspension point with individually controllable suspension and one suspension point without individually controllable suspension.

[0052] As illustrated by step 120, the method 100 comprises transforming the motion requests to the actuator instructions. During the transformation of step 120, constraints on lateral and / or longitudinal forces are applied, as illustrated by sub-step 121.

[0053] The respective lateral and / or longitudinal forces are associated with respective suspension points. For example, the lateral and / or longitudinal forces of a wheel may be associated with the suspension point that controls the vertical force carried by that wheel.

[0054] The constraints on lateral and / or longitudinal forces are dynamically varying in dependence on the dynamic distribution of vertical force. Thus, the suspension actuators are operable to dynamically vary constraints on lateral and / or longitudinal forces among different wheels (or group of wheels). For example, a relation among different wheels (or group of wheels) between the radii of the friction circles may be dynamically varied.

[0055] As illustrated by step 130, the method 100 also comprises operating the plurality of motion support devices (including the one or more individually controllable suspension actuators) accordingly. Thus, the vehicle is configured to respond to the motion requests by operating the plurality of motion support devices in response to the actuator instructions from the control allocator.

[0056] As exemplified above, the dynamic distribution of vertical force may be used (in the transformation of motion requests to actuator instructions) to counteract a variation of external friction conditions among wheels of the vehicle. The external friction conditions may relate to any characteristics of the vehicle environment that affect the friction. Examples include slipperiness of the ground surface (e.g., depending on whether the wheel rests on asphalt, ice, gravel, etc. and / or whether the surface is dry, damp, snowy, etc.), and gradient of the ground surface (e.g., slope and banking experienced by the wheel). For example, more or less vertical force may be allocated to a wheel with slippery conditions than to other wheel(s) as mentioned above. Alternatively or additionally, more or less vertical force may be allocated to a wheel experiencing severe banking than to other wheel(s).

[0057] As also exemplified above, the dynamic distribution of vertical force may - alternatively or additionally - be used (in the transformation of motion requests to actuator instructions) to enable allocation of lateral and / or longitudinal forces as required for accomplishing a vehicle manoeuver indicated by the motion requests. For example, more vertical force may be allocated to wheel(s) at the inner side of a curvature than to wheel(s) atthe outer side of the curvature as mentioned above, and / or vertical force may be re-allocated to enable braking (e.g., in a downhill situation).

[0058] The individually controllable suspension actuators are typically handled together with the other motion support devices when the motion requests are transformed to the actuator instructions. Thereby, the vertical force distribution is determined jointly with the other forces (and moments) by the control allocator; allowing for flexible force allocation as well as enabling improvements compared to an approach where the vertical force distribution is determined before the other forces (and moments).

[0059] The joint determination may be implemented in any suitable way. For example, the dynamic distribution of vertical force may be expressed via vertical force variables (among variables for other forces and moments) in a control allocation problem applied to transform the motion requests to the actuator instructions. Alternatively or additionally, a control allocation problem may comprise a component that represents a cost of operating the suspension actuators (among components representing the costs of operating other actuators).

[0060] Example formulations of a control allocation problem include power loss minimization such as u* = argmin( Pioss(u)') , Bu = v,uL< u < u , and forces error minimization such as u* = argwherein v represents inputs (e.g., global forces) that depend on the motion requests, u represents actuation variables (among which are the vertical force variables), uDrepresents desired actuation, and u* represents the determined actuator instructions. The inequalities uL< u < uvrepresent the operational limits of the actuators, and B represents a transfer function. The power loss for the actuators is represented by Pjoss(u) and may be seen as a cost for using that actuator (i.e., a cost component), lllVu(a — b) || 2 represents a measure of distance between a and b and may be seen as an expression of cost for an actuator setting, and y represents a weighting factor.

[0061] For example, when the control allocation problem aims towards minimization of the power loss, an extra term PiOss,sus .usus>Ucurr) representing the power needed to actuate the suspension system may be added in the sum Pjoss(k), wherein ususrepresents the suspension actuation variables, and ucurrrepresents the currently applied suspension actuation (e.g., estimated from suspension sensors, or based on previous values of usus.

[0062] For example, the power losses of the suspension actuators may be modelled as proportional to the absolute value of the change in suspension actuator position with respectto the current value: Pioss,sus(.usus>Ucurr)~ |wsus—Ucurr L i e., ifnochange in the displacement of suspension is needed, the power loss is assumed to be zero.

[0063] It should be noted that ususcould be expressed in any suitable way, e.g., as a roll angle of an axle, a roll angle of the vehicle, a displacement of suspension (such as a heave), etc. Then, the implementation of ususcould involve low-level controllers of the suspension system (e.g., using valves, pumps, etc.).

[0064] It should be noted that the approaches suggested herein are not limited to the use of these specific control allocation problem formulations. Contrarily, any suitable control allocation problem formulation may be used.

[0065] It should also be noted that the global forces may be selected to ensure that the control allocation problem has a solution. For example, from initial global forces may be determined from the motion requests (e.g., global forces that fulfill the motion requests) and the initial global forces may be adjusted iteratively using the control allocation problem and a prioritization among the global forces such that a solution can be found.

[0066] Alternatively or additionally to letting the dynamic distribution of vertical force be expressed via vertical force variables in a control allocation problem, and / or letting a control allocation problem comprise a component that represents a cost of operating the suspension actuators, the joint determination may be implemented by letting the lateral force (for steered and / or non-steered wheels) include a term to express the controllable suspension actuators’ contribution to the lateral force (steer by suspension). Thereby, a desired lateral force may be fulfilled by the steering system (when applicable) and / or the suspension system. For example, a control allocation problem could be applied to determine how fulfillment of the lateral force should be achieved based on the capabilities of the actuators for steering and suspension and / or based on the cost associated with the use of the actuators for steering and suspension.

[0067] In some examples, the method 100 may further comprise applying a rollover avoidance constraint when transforming the motion requests to the actuator instructions, as illustrated by optional sub-step 122. For example, the rollover avoidance constraint may limit the dynamic distribution of vertical force (e.g., by hindering distribution of vertical force that risks causing vehicle rollover).

[0068] Typically, the rollover avoidance constraint varies dynamically depending on the maneuvering of the vehicle. For example, when the vehicle is negotiating a right turn, the vertical forces of the left side of the vehicle may be more restricted and / or the vertical forcesof the right side of the vehicle may be less restricted than when the vehicle is travelling straight forward.

[0069] In some examples, the method 100 may further comprise applying a tire load constraint when transforming the motion requests to the actuator instructions, as illustrated by optional sub-step 123. For example, the tire load constraint may limit the dynamic distribution of vertical force (e.g., by hindering distribution of vertical force that risks causing excessive or uneven wear, or tire failure such as a tire explosion).

[0070] In some examples, the method 100 may further comprise predicting upcoming motion requests, as illustrated by optional step 110. For example, the prediction may be accomplished by extrapolation of current and previous motion requests. Alternatively or additionally, the prediction may be based on positioning and infrastructure information (e.g., knowledge that a downhill or curvature portion of the road is approaching). Yet alternatively or additionally, the prediction may be based on sensor data (e.g., information from a forwardlooking camera that an obstacle or a curvature portion of the road is approaching).

[0071] When there is predicted upcoming motion requests available, step 120 may be performed based on the predicted motion requests (instead of, or in addition to, the actual motion requests). Thus, the control allocator may be caused to transform the predicted motion requests to actuator instructions. Thereby, step 130 may comprise operating the actuators in a proactive manner (preparing the vehicle - e.g., the vertical force distribution - for a situation that is likely upcoming). For example, if it is a curvature maneuver is predicted, the vertical force may be proactively distributed such that more load is allocated to the inner side of the curvature.

[0072] FIG. 2 schematically illustrates an example vehicle 200 for cargo transport where the techniques disclosed herein can be advantageously applied. The vehicle 200 comprises a truck / tractor / towing unit 210 configured to tow one or more trailer unit(s) 220 in a known manner.

[0073] The vehicle may comprise a plurality of motion support devices configured to actuate the vehicle; including one or more individually controllable suspension actuators 231, 232, 233 configured to cause dynamic distribution of vertical force among suspension points of the vehicle 200.

[0074] Generally, the suspension points of the vehicle may be individually controllable, and / or may be group-wise controllable (e.g., a pair of suspension points may be jointlycontrolled). Thus, depending on the setup of the suspension actuators in relation to the suspension points, and how each of the suspension points is associated with the wheels of the vehicle, it may be possible to distribute vertical force per wheel, per wheel pair, per wheel axle, per vehicle side, etc.

[0075] In the example of FIG. 2, where a left side of the vehicle 200 is shown, there is one suspension actuator 231 that controls vertical force for the wheel 241 of truck / tractor / towing unit 210, one suspension actuator 232 that controls vertical force for the front wheels pair 242 of the trailer unit 220, and one suspension actuator 233 that controls vertical force for the rear wheels pair 243 of the trailer unit 220. Corresponding suspension actuators may be provided for the right side of the vehicle 200.

[0076] The tractor unit 210 and / or the trailer unit(s) 220 may comprise a vehicle control unit (VCU) 290 configured to perform various vehicle (unit) control functions, such as vehicle motion management (VMM). For example, any of one or more VCU(s) 290 may be configured to perform one or more steps of the method 100 of FIG. 1 in relation to the individually controllable suspension actuators 231, 232, 233. Thus, the techniques disclosed herein may be performed by any of one or more VCU(s) 290.

[0077] FIG. 3 schematically illustrates functionality 300 for actuation control of a wheel 310 and a corresponding suspension point (SUS) 390 according to some examples.

[0078] The control of the wheel 310 and the suspension point 390 is performed via some example motion support devices (MSDs) 320; here comprising a propulsion device (PR) 321, such as an electric machine (EM), a power steering arrangement (ST) 322, and a suspension actuator (SA) 323 configured to control the vertical force of the suspension point 390. The propulsion device 321, the power steering arrangement 322, and the suspension actuator 323 are examples of actuators which can be controlled by one or more MSD control units. It should be noted that any suitable actuator(s) may be used as MSD(s), and that FIG. 3 only represents an example set of MSDs. Other examples include various types of brakes.

[0079] A vehicle motion management (VMM) function 350 may be employed to perform force allocation to meet received motion requests (REQ) 340 in a safe and robust manner. The VMM function 350 communicates actuator instructions to the different MSDs via MDS control unit(s). The VMM function 350 manages both force generation and MSD coordination; i.e., it determines what forces are required for different wheels, suspension points, and vehicle units in order to fulfil the motion requests 340, for instance to acceleratethe vehicle according to a requested acceleration profile and / or to generate a requested curvature motion by the vehicle.

[0080] For example, the VMM function 350 may be comprised in a, such as the VCU 290 of FIG. 2. Alternatively or additionally, the VMM function 350 may be configured to cause execution of (e.g., may be configured to perform) one or more steps of the method 100 of FIG. 1

[0081] The VMM function 350 is configured to apply constraints on lateral and / or longitudinal forces (e.g., per wheel 310) as a part of transforming motion requests to actuator instructions, wherein the lateral and / or longitudinal forces are associated with a respective suspension point 390, and wherein the constraints on lateral and / or longitudinal forces are dynamically varying in dependence on the vertical force for the suspension point 390 as described and exemplified herein. To this end the VMM function 350 may have access to estimated values of one or more parameters (e.g., tire-road friction). For example, the parameter information may be received from another functional unit of the vehicle, or may be determined by the VMM function 350 function itself (e.g., based on sensor data).

[0082] The VMM function 350 comprises a control allocator (CA) 351 for transforming the motion requests to actuator instructions, and the control allocator 351 may be configured to apply the constraints on lateral and / or longitudinal forces. Thus, a vehicle comprising the functionality 300 is configured to respond to the motion requests 340 by operating a plurality of motion support devices 320 in response to actuator instructions from the control allocator 351

[0083] It should be noted that the MSDs 320 typically includes more actuators than those illustrated in FIG. 3. For example, a vehicle may comprise several wheels 310 with steering and / or propulsion, as well as several controllable suspension points 390.

[0084] It should also be noted that the motion requests 340 may comprise any applicable requests for vehicle motion; e.g., requests caused by an operator / driver of the vehicle, and / or requests generated by an autonomous driving system.

[0085] FIG. 4 schematically illustrates a bottom view of a vehicle 400 with two vehicle units and six wheels 431, 432, 433, 441, 442, 443. For example, the vehicle 400 may be seen as a schematic representation of the vehicle 200 of FIG. 2 (wherein each of the wheel pairs 242, 243 of the trailer unit 220 is represented by a single wheel 432, 433).

[0086] As already mentioned, it may be possible to distribute vertical force per wheel, per wheel pair, per wheel axle, per vehicle side, etc., depending on the setup of the suspension actuators in relation to the suspension points, and how each of the suspension points is associated with the wheels of the vehicle. FIG. 4 illustrates a situation with six suspension points 411, 412, 413, 421, 422, 423, each associated with a respective one of the wheels 431, 432, 433, 441, 442, 443

[0087] Assuming that each suspension point 411, 412, 413, 421, 422, 423 is associated with its own individually controllable suspension actuator (e.g., suspension point 411 controlled by suspension actuator 231 of FIG. 2, suspension point 412 controlled by suspension actuator 232 of FIG. 2, etc.), the vertical force (corresponding to the weight of the vehicle units) may be dynamically distributed among the wheels 431, 432, 433, 441, 442, 443. Typically, the vertical force corresponding to the weight of the towing unit may be dynamically distributed between the wheels 431, 441, and the vertical force corresponding to the weight of the trailer unit may be dynamically distributed among the wheels 432, 433, 442, 443. However, dynamic distribution of vertical force between different vehicle units may also be possible.

[0088] To exemplify possibilities of the approaches suggested herein, if wheel 432 is spinning (indicating slippery condition), the vertical force may be increased for suspension point 412 until the spinning stops (i.e., grip is achieved). If the spinning continued despite increased vertical force, the vertical force may instead be decreased for suspension point 412 to enable better grip for the other wheels 433, 442, 443 of the vehicle unit.

[0089] To further exemplify possibilities of the approaches suggested herein, when a left turn curvature is to be negotiated, the vertical force may be increased for suspension points 411, 412, 413, to decrease the roll angle during the maneuver.

[0090] FIG. 5 schematically illustrates value regions of lateral and longitudinal forces according to some examples. The diagram shows the lateral force Fyon the horizontal axis (x-axis), and the longitudinal force Fxon the vertical axis (y-axis). A value region corresponds to allowed force allocation and is exemplified in FIG. 5 in the form of the interior of friction circles 501, 502, 503, wherein each friction circle can be expressed as Fx+ Fy = R and the corresponding value region as Fx+ Fy< R.

[0091] The friction circles 501, 502, 503 are examples of constraints on lateral and / or longitudinal forces applicable during transformation of the motion requests to the actuatorinstructions. By dynamically varying the vertical force for a suspension point as elaborated herein, the radius R of the friction circle varies correspondingly for a wheel associated with the suspension point. Thereby, the allowable values of the lateral and longitudinal forces for that wheel may be dynamically adjusted. For example, for a specific wheel i, the value region may typically be specified via the expression F^ +< ^Fzl, wherein represents the friction coefficient experience by the wheel, Fxiand Fyirepresent the longitudinal and lateral forces for the wheel, and Fzirepresents the vertical force transferred from the associated suspension point to the wheel.

[0092] Some further exemplification will now be provided regarding the joint determination by the control allocator of the vertical force distribution with the other forces (and moments), particularly relevant when a control allocation problem applied to transform the motion requests to the actuator instructions.

[0093] According to this exemplification, the longitudinal force Fxifor wheel i is a function of the motion support devices affecting (e.g., acting on) the wheel, i.e., Fxi(u), wherein u represents actuation variables for the relevant motion support devices (e.g., service brake torque or force, contribution by an electric machine or engine, etc.). For simplicity, any contribution on Fxiby the yaw rate and / or by the lateral velocity is assumed negligible.

[0094] According to this exemplification, the vertical force Fzi(usus) for wheel i may be a function of the suspension actuation variables usus, wherein the function is in the form of a map- or model-based algorithm (e.g., a polynomial approximation). For a specified vehicle (or axle) motion and a setting of the suspension actuation variables, the function algorithm yields knowledge regarding gain or loss in vertical force at the wheel(s).

[0095] For example, the function algorithm may specify that - for a specific roll angle - the distribution of vertical force between two (left and right) wheels on the same wheel axle varies linearly with the actuation variables for the two suspension points of the wheel axle (while the sum of vertical forces for the two wheels may be constant).

[0096] Other variables that may affect the vertical force for wheel i include the weight Fzi, statatthe wheel for a static weight distribution, the current vertical load Fzi dynat the wheel, and the longitudinal and / or lateral acceleration ax, ayused to calculate the longitudinal and lateral load transfer at the wheel. For example, the vertical force may be expressed

[0097] The lateral force Fyifor wheel i typically depends on the tire slip angle aL. For low magnitudes of the slip, the relationship may be assumed to be linear, i.e., Fyi= — Ca.a where Ca. represents cornering stiffness. Assuming that only the front axle is steerable, a typical slip angle assumption for the rear wheels (i = 3,4) and— 8 for the front wheels (i = 1,2), where 8 represents the steeringangle, ft represents the sideslip, vxrepresents the longitudinal speed, mzrepresents the yaw rate, Lrrepresents a longitudinal distance from the rear axle to the center of gravity, and L represents a longitudinal distance from the front axle to the center of gravity. An alternative way for expressing the lateral force Fyifor wheel i is Fyi=where g is the gravity constant, ayrepresents lateral acceleration, mzrepresents yaw acceleration, and Lj equals L or Lrdepending on the wheel axle of the considered wheel. This alternative way of expressing the lateral force may be particularly suitable when the steering angle 8 is not controlled by the control allocator, or is controlled in an outer loop of the control allocation when the lateral force is controlled in an inner loop.

[0098] As already mentioned, the constraints on lateral and / or longitudinal forces may be expressed via Fxi+ Fyi< g Fzi, where the longitudinal force depends on actuation variables u (which typically do not include suspension actuation variables usus) Fxi= Fxi(u), the vertical force depends on suspension actuation variables usus. Fzi= Fzi(usus), and the lateral force may depend on actuation variables u and suspension actuation variables usus. yi Fyi .FZi) Fyi(u, Usus) .

[0099] Using the previous exemplification, these constraints may be expressed via constraints on lateral force as | Fxi(u) | < Fzi(usus, whichillustrates dependency on suspension actuation variables usus. It should be noted that the lateral force Fyiis within the friction circle when

[0100] FIG. 6 schematically illustrates a rear view of a vehicle 600 according to some examples. For example, the vehicle 600 may be seen as a schematic representation of the vehicle 200 of FIG. 2 and / or the vehicle 400 of FIG. 4.

[0101] FIG. 6 illustrates a situation where the vehicle 600 leans towards the right (e.g., due to negotiation of a leftward curvature). When such leaning becomes too large, there is arisk of vehicle rollover. Therefore, it may be beneficial to implement rollover protection to avoid excessive leaning of the vehicle.

[0102] As already mentioned, a rollover avoidance constraint may be included when transforming motion requests to actuator instructions, wherein the rollover avoidance constraint limits the dynamic distribution of vertical force. Thereby, the suspension actuators are (at least to some extent) hindered to operate in a manner that causes the vehicle to rollover.

[0103] An example rollover avoidance constraint may be expressed via the formulation vehicle withfour controllable suspension points, wherein t - represents the front axle track width, trrepresents the rear axle track width 640, m represents the mass of the vehicle, ayiCrit represents a (typically tunable) threshold for lateral acceleration beyond which the risk of rollover is considered too high, and h represents a height 630 from ground level to a center of gravity 610 of the vehicle 600.

[0104] Forces acting on the center of gravity 610 include a gravitational force mg 611, and a lateral force — may612. Forces acting on the wheels include vertical forces Fzi621, 622, and lateral forces Fyi623, 624.

[0105] As also mentioned already, a tire load constraint may be included when transforming motion requests to actuator instructions, wherein the tire load constraint limits the dynamic distribution of vertical force. Thereby, the suspension actuators are (at least to some extent) hindered to operate in a manner that causes excessive tire wear or other tire damage. The tire load constraint may be applied instead of, or in addition to, the rollover avoidance constraint.

[0106] Alternatively or additionally to the already mentioned constraints, there may be applied a constraint on the vertical force difference between left and right side wheels of the same wheel axle (e.g., to enforce similar longitudinal slip and / or similar tire wear).

[0107] According to some examples, the individually controllable suspension actuators may - additionally or alternatively - be used to adjust the pitch moment Myand / or the roll moment Mx. For example, desired values of pitch and / or roll moments My des, Mx desmay be used in the control allocation problem; My(itsus) = My des+ syand / or Mx(usus) = Mx des+sx, where syand sxrepresent slack variables which may be associated with a cost when having non-zero value.

[0108] FIG. 7 is a schematic diagram of a computer system 700 for implementing examples disclosed herein. For example, the computer system 700 (or part thereof) may be comprised in the VCU 290 of FIG. 2. Alternatively or additionally, the computer system 700 may be configured to cause execution of (e.g., may be configured to perform) one or more steps of the method 100 of FIG. 1. Yet alternatively or additionally, the computer system 700 may be configured to implement the VMM function 350 of FIG. 3.

[0109] The computer system 700 is adapted to execute instructions from a computer- readable medium to perform these and / or any of the functions or processing described herein. The computer system 700 may be connected (e.g., networked) to other machines in a LAN (Local Area Network), LIN (Local Interconnect Network), automotive network communication protocol (e.g., FlexRay), an intranet, an extranet, or the Internet. While only a single device is illustrated, the computer system 700 may include any collection of devices that individually or jointly execute a set (or multiple sets) of instructions to perform any one or more of the methodologies discussed herein. Accordingly, any reference in the disclosure and / or claims to a computer system, computing system, computer device, computing device, control system, control unit, electronic control unit (ECU), processor device, processing circuitry, etc., includes reference to one or more such devices to individually or jointly execute a set (or multiple sets) of instructions to perform any one or more of the methodologies discussed herein. For example, control system may include a single control unit or a plurality of control units connected or otherwise communicatively coupled to each other, such that any performed function may be distributed between the control units as desired. Further, such devices may communicate with each other or other devices by various system architectures, such as directly or via a Controller Area Network (CAN) bus, etc.

[0110] The computer system 700 may comprise at least one computing device or electronic device capable of including firmware, hardware, and / or executing software instructions to implement the functionality described herein. The computer system 700 may include processing circuitry 702 (e.g., processing circuitry including one or more processor devices or control units), a memory 704, and a system bus 706. The computer system 700 may include at least one computing device having the processing circuitry 702. The system bus 706 provides an interface for system components including, but not limited to, thememory 704 and the processing circuitry 702. The processing circuitry 702 may include any number of hardware components for conducting data or signal processing or for executing computer code stored in memory 704. The processing circuitry 702 may, for example, include a general-purpose processor, an application specific processor, a Digital Signal Processor (DSP), an Application Specific Integrated Circuit (ASIC), a Field Programmable Gate Array (FPGA), a circuit containing processing components, a group of distributed processing components, a group of distributed computers configured for processing, or other programmable logic device, discrete gate or transistor logic, discrete hardware components, or any combination thereof designed to perform the functions described herein. The processing circuitry 702 may further include computer executable code that controls operation of the programmable device.[OHl] The system bus 706 may be any of several types of bus structures that may further interconnect to a memory bus (with or without a memory controller), a peripheral bus, and / or a local bus using any of a variety of bus architectures. The memory 704 may be one or more devices for storing data and / or computer code for completing or facilitating methods described herein. The memory 704 may include database components, object code components, script components, or other types of information structure for supporting the various activities herein. Any distributed or local memory device may be utilized with the systems and methods of this description. The memory 704 may be communicably connected to the processing circuitry 702 (e.g., via a circuit or any other wired, wireless, or network connection) and may include computer code for executing one or more processes described herein. The memory 704 may include non-volatile memory 708 (e.g., read-only memory (ROM), erasable programmable read-only memory (EPROM), electrically erasable programmable read-only memory (EEPROM), etc.), and volatile memory 710 (e.g., randomaccess memory (RAM)), or any other medium which can be used to carry or store desired program code in the form of machine-executable instructions or data structures and which can be accessed by a computer or other machine with processing circuitry 702. A basic input / output system (BIOS) 712 may be stored in the non-volatile memory 708 and can include the basic routines that help to transfer information between elements within the computer system 700.

[0112] The computer system 700 may further include or be coupled to a non-transitory computer-readable storage medium such as the storage device 714, which may comprise, forexample, an internal or external hard disk drive (HDD) (e.g., enhanced integrated drive electronics (EIDE) or serial advanced technology attachment (SATA)), HDD (e.g., EIDE or SATA) for storage, flash memory, or the like. The storage device 714 and other drives associated with computer-readable media and computer-usable media may provide nonvolatile storage of data, data structures, computer-executable instructions, and the like.

[0113] Computer-code which is hard or soft coded may be provided in the form of one or more modules. The module(s) can be implemented as software and / or hard-coded in circuitry to implement the functionality described herein in whole or in part. The modules may be stored in the storage device 714 and / or in the volatile memory 710, which may include an operating system 716 and / or one or more program modules 718. All or a portion of the examples disclosed herein may be implemented as a computer program 720 stored on a transitory or non-transitory computer-usable or computer-readable storage medium (e.g., single medium or multiple media), such as the storage device 714, which includes complex programming instructions (e.g., complex computer-readable program code) to cause the processing circuitry 702 to carry out actions described herein. Thus, the computer-readable program code of the computer program 720 can comprise software instructions for implementing the functionality of the examples described herein when executed by the processing circuitry 702. In some examples, the storage device 714 may be a computer program product (e.g., readable storage medium) storing the computer program 720 thereon, where at least a portion of a computer program 720 may be loadable (e.g., into a processor) for implementing the functionality of the examples described herein when executed by the processing circuitry 702. The processing circuitry 702 may serve as a controller or control system for the computer system 700 that is to implement the functionality described herein.

[0114] The computer system 700 may include an input device interface 722 configured to receive input and selections to be communicated to the computer system 700 when executing instructions, such as from a keyboard, mouse, touch-sensitive surface, etc. Such input devices may be connected to the processing circuitry 702 through the input device interface 722 coupled to the system bus 706 but can be connected through other interfaces, such as a parallel port, an Institute of Electrical and Electronic Engineers (IEEE) 1394 serial port, a Universal Serial Bus (USB) port, an IR interface, and the like. The computer system 700 may include an output device interface 724 configured to forward output, such as to a display, a video display unit (e.g., a liquid crystal display (LCD) or a cathode ray tube(CRT)). The computer system 700 may include a communications interface 726 suitable for communicating with a network as appropriate or desired.

[0115] The operational actions described in any of the exemplary aspects herein are described to provide examples and discussion. The actions may be performed by hardware components, may be embodied in machine-executable instructions to cause a processor to perform the actions, or may be performed by a combination of hardware and software. Although a specific order of method actions may be shown or described, the order of the actions may differ. In addition, two or more actions may be performed concurrently or with partial concurrence.

[0116] The described examples and their equivalents may be realized in software or hardware or a combination thereof. The examples may be performed by general purpose circuitry. Examples of general purpose circuitry include digital signal processors (DSP), central processing units (CPU), co-processor units, field programmable gate arrays (FPGA) and other programmable hardware. Alternatively or additionally, the examples may be performed by specialized circuitry, such as application specific integrated circuits (ASIC). The general purpose circuitry and / or the specialized circuitry may, for example, be associated with or comprised in an electronic apparatus such as a VCU.

[0117] The electronic apparatus may comprise arrangements, circuitry, and / or logic according to any of the examples described herein. Alternatively or additionally, the electronic apparatus may be configured to perform method steps according to any of the examples described herein.

[0118] According to some examples, a computer program product comprises a non- transitory computer readable medium such as, for example, a universal serial bus (USB) memory, a plug-in card, an embedded drive, or a read only memory (ROM). FIG. 8 illustrates a computer program product exemplified as a non-transitory computer-readable medium in the form of a compact disc (CD) ROM 800. The computer-readable medium has stored thereon program code 840 comprising instructions. The program code is loadable into processing circuitry (PROC; e.g., a data processing unit) 820, which may, for example, be comprised in a VCU 810. When loaded into the processing circuitry, the program code may be stored in a memory (MEM) 830 associated with, or comprised in, the processing circuitry. According to some examples, the program code may, when loaded into, and run by, theprocessing circuitry, cause execution of method steps according to any of the methods described herein; such as the method discussed in connection to FIG. 1.

[0119] FIG. 9 schematically illustrates, in terms of a number of functional units, the components of a control unit 900 according to some examples. This control unit 900 may be comprised in the vehicle 200; e.g., in the form of a VCU 290. Processing circuitry 910 is provided using any combination of one or more of a suitable central processing unit CPU, multiprocessor, microcontroller, digital signal processor DSP, etc., capable of executing software instructions stored in a computer program product, e.g. in the form of a storage medium 930. The processing circuitry 910 may further be provided as at least one application specific integrated circuit ASIC, or field programmable gate array FPGA.

[0120] Particularly, the processing circuitry 910 is configured to cause the control unit 900 to perform a set of operations, or steps, according to any of the methods described herein; such as the method discussed in connection to FIG. 1. Consequently, there is disclosed herein a control unit 900 for controlling a heavy-duty vehicle 200 as described herein.

[0121] For example, the storage medium 930 may store the set of operations, and the processing circuitry 910 may be configured to retrieve the set of operations from the storage medium 930 to cause the control unit 900 to perform the set of operations. The set of operations may be provided as a set of executable instructions. Thus, the processing circuitry 910 is thereby arranged to execute method steps as herein disclosed. In particular, there is disclosed a control unit 900 for controlling an articulated vehicle 200 comprising a tractor 210 and / or one or more towed vehicle units 220, the control unit comprising processing circuitry 910, an interface 920 coupled to the processing circuitry 910, and a memory 930 coupled to the processing circuitry 910, wherein the memory comprises machine readable computer program instructions that, when executed by the processing circuitry, causes the control unit to perform any one or more of the method steps discussed herein.

[0122] The storage medium 930 may also comprise persistent storage, which, for example, can be any single one or combination of magnetic memory, optical memory, solid state memory or even remotely mounted memory.

[0123] The control unit 900 may further comprise an interface 920 for communications with at least one external device. As such, the interface 920 may comprise one or more transmitters and receivers, comprising analogue and digital components and a suitable number of ports for wireline or wireless communication.

[0124] The processing circuitry 910 controls the general operation of the control unit 900, e.g., by sending data and control signals to the interface 920 and the storage medium 930, by receiving data and reports from the interface 920, and by retrieving data and instructions from the storage medium 930. Other components, as well as the related functionality, of the control node are omitted in order not to obscure the concepts presented herein.A non-exhaustive list of Examples:

[0125] Example 1: A computer system for dynamic grip control of a vehicle, wherein the vehicle comprises a plurality of motion support devices for actuating the vehicle and a control allocator configured to transform motion requests to actuator instructions, wherein the motion support devices include one or more individually controllable suspension actuators configured to cause dynamic distribution of vertical force among suspension points of the vehicle, and wherein the vehicle is configured to respond to the motion requests by operating the plurality of motion support devices, including the one or more individually controllable suspension actuators, in response to the actuator instructions from the control allocator, the computer system comprising processing circuitry configured to apply constraints on lateral and / or longitudinal forces during transformation of the motion requests to the actuator instructions, wherein respective lateral and / or longitudinal forces are associated with respective suspension points, and wherein the constraints on lateral and / or longitudinal forces are dynamically varying in dependence on the dynamic distribution of vertical force.

[0126] Example 2: The computer system of Example 1, wherein the dynamic distribution of vertical force is expressed via vertical force variables in a control allocation problem applied to transform the motion requests to the actuator instructions.

[0127] Example 3: The computer system of Example 2, wherein the control allocation problem comprises a component that represents a cost of operating the suspension actuators.

[0128] Example 4: The computer system of any of Examples 1-3, wherein the processing circuitry is further configured to cause the dynamic distribution of vertical force to be used, during the transformation of the motion requests to the actuator instructions, to counteract a variation of external friction conditions among wheels of the vehicle.

[0129] Example 5: The computer system of any of Examples 1-4, wherein the processing circuitry is further configured to cause the dynamic distribution of vertical force to be used, during the transformation of the motion requests to the actuator instructions, toenable allocation of lateral and / or longitudinal forces as required for accomplishing a vehicle manoeuver indicated by the motion requests.

[0130] Example 6: The computer system of any of Examples 1-5, wherein the processing circuitry is further configured to apply a rollover avoidance constraint during the transformation of the motion requests to the actuator instructions, wherein the rollover avoidance constraint limits the dynamic distribution of vertical force.

[0131] Example 7: The computer system of any of Examples 1-6, wherein the processing circuitry is further configured to apply a tire load constraint during the transformation of the motion requests to the actuator instructions, wherein the tire load constraint limits the dynamic distribution of vertical force.

[0132] Example 8: The computer system of any of Examples 1-7, wherein the processing circuitry is further configured to predict upcoming motion requests, and cause the control allocator to transform the predicted motion requests to actuator instructions for proactive operation of the suspension actuators.

[0133] Example 9: A computer-implemented method for dynamic grip control of a vehicle, wherein the vehicle comprises a plurality of motion support devices for actuating the vehicle and a control allocator for transforming motion requests to actuator instructions, wherein the motion support devices include one or more individually controllable suspension actuators configured to cause dynamic distribution of vertical force among suspension points of the vehicle, and wherein the vehicle is configured to respond to the motion requests by operating the plurality of motion support devices, including the one or more individually controllable suspension actuators, in response to the actuator instructions from the control allocator, the method comprising applying, by a processor device of a computer system, constraints on lateral and / or longitudinal forces when transforming the motion requests to the actuator instructions, wherein respective lateral and / or longitudinal forces are associated with respective suspension points, and wherein the constraints on lateral and / or longitudinal forces are dynamically varying in dependence on the dynamic distribution of vertical force.

[0134] Example 10: The method of Example 9, wherein the dynamic distribution of vertical force is expressed via vertical force variables in a control allocation problem applied to transform the motion requests to the actuator instructions.

[0135] Example 11: The method of Example 10, wherein the control allocation problem comprises a component that represents a cost of operating the suspension actuators.

[0136] Example 12: The method of any of Examples 9-11, wherein the dynamic distribution of vertical force is used, when transforming the motion requests to the actuator instructions, to counteract a variation of external friction conditions among wheels of the vehicle.

[0137] Example 13: The method of any of Examples 9-12, wherein the dynamic distribution of vertical force is used, when transforming the motion requests to the actuator instructions, to enable allocation of lateral and / or longitudinal forces as required for accomplishing a vehicle manoeuver indicated by the motion requests.

[0138] Example 14: The method of any of Examples 9-13, further comprising applying, by the processor device, a rollover avoidance constraint when transforming the motion requests to the actuator instructions, wherein the rollover avoidance constraint limits the dynamic distribution of vertical force.

[0139] Example 15: The method of any of Examples 9-14, further comprising applying, by the processor device, a tire load constraint when transforming the motion requests to the actuator instructions, wherein the tire load constraint limits the dynamic distribution of vertical force.

[0140] Example 16: The method of any of Examples 9-15, further comprising predicting, by the processor device, upcoming motion requests, and causing, by the processor device, the control allocator to transform the predicted motion requests to actuator instructions for proactive operation of the suspension actuators.

[0141] Example 17: A vehicle comprising the computer system of any of Examples 1-8 and / or a processor device configured to perform the method of any of Examples 9-16.

[0142] Example 18: The vehicle of Example 17, further comprising a plurality of motion support devices configured to actuate the vehicle and a control allocator configured to transform motion requests to actuator instructions, wherein the motion support devices include one or more individually controllable suspension actuators configured to cause dynamic distribution of vertical force among suspension points of the vehicle, and wherein the vehicle is configured to respond to the motion requests by operating the plurality of motion support devices, including the one or more individually controllable suspension actuators, in response to the actuator instructions from the control allocator.

[0143] Example 19: A computer program product comprising program code for performing, when executed by a processor device, the method of any of Examples 9-16.

[0144] Example 20: A non-transitory computer-readable storage medium comprising instructions, which when executed by a processor device, cause the processor device to perform the method of any of Examples 9-16.

[0145] The terminology used herein is for the purpose of describing particular aspects only and is not intended to be limiting of the disclosure. As used herein, the singular forms "a," "an," and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise. As used herein, the term "and / or" includes any and all combinations of one or more of the associated listed items. It will be further understood that the terms "comprises," "comprising," "includes," and / or "including" when used herein specify the presence of stated features, integers, actions, steps, operations, elements, and / or components, but do not preclude the presence or addition of one or more other features, integers, actions, steps, operations, elements, components, and / or groups thereof.

[0146] It will be understood that, although the terms first, second, etc., may be used herein to describe various elements, these elements should not be limited by these terms. These terms are only used to distinguish one element from another. For example, a first element could be termed a second element, and, similarly, a second element could be termed a first element without departing from the scope of the present disclosure.

[0147] Relative terms such as "below" or "above" or "upper" or "lower" or "horizontal" or "vertical" may be used herein to describe a relationship of one element to another element as illustrated in the Figures. It will be understood that these terms and those discussed above are intended to encompass different orientations of the device in addition to the orientation depicted in the Figures. It will be understood that when an element is referred to as being "connected" or "coupled" to another element, it can be directly connected or coupled to the other element, or intervening elements may be present. In contrast, when an element is referred to as being "directly connected" or "directly coupled" to another element, there are no intervening elements present.

[0148] Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure belongs. It will be further understood that terms used herein should be interpreted as having a meaning consistent with their meaning in the context of thisspecification and the relevant art and will not be interpreted in an idealized or overly formal sense unless expressly so defined herein.

[0149] It is to be understood that the present disclosure is not limited to the aspects described above and illustrated in the drawings; rather, the skilled person will recognize that many changes and modifications may be made within the scope of the present disclosure and appended claims. In the drawings and specification, there have been disclosed aspects for purposes of illustration only and not for purposes of limitation, the scope of the disclosure being set forth in the following claims.

Claims

ClaimsWhat is claimed is:

1. A computer system (290, 700) for dynamic grip control of a vehicle (200), wherein the vehicle comprises a plurality of motion support devices (320) for actuating the vehicle and a control allocator (351) configured to transform motion requests to actuator instructions, wherein the motion support devices include one or more individually controllable suspension actuators (231, 232, 233, 323) configured to cause dynamic distribution of vertical force among suspension points (411, 412, 413, 421, 422, 423) of the vehicle, and wherein the vehicle is configured to respond to the motion requests by operating the plurality of motion support devices, including the one or more individually controllable suspension actuators, in response to the actuator instructions from the control allocator, the computer system comprising processing circuitry (702) configured to apply constraints (501, 502, 503) on lateral and / or longitudinal forces during transformation of the motion requests to the actuator instructions, wherein respective lateral and / or longitudinal forces are associated with respective suspension points, and wherein the constraints on lateral and / or longitudinal forces are dynamically varying in dependence on the dynamic distribution of vertical force.

2. The computer system of claim 1, wherein the processing circuitry is further configured to cause the dynamic distribution of vertical force to be used, during the transformation of the motion requests to the actuator instructions, to counteract a variation of external friction conditions among wheels of the vehicle.

3. The computer system of any of claims 1-2, wherein the processing circuitry is further configured to cause the dynamic distribution of vertical force to be used, during the transformation of the motion requests to the actuator instructions, to enable allocation of lateral and / or longitudinal forces as required for accomplishing a vehicle manoeuver indicated by the motion requests.

4. A computer-implemented method (100) for dynamic grip control of a vehicle (200), wherein the vehicle comprises a plurality of motion support devices (320) for actuating thevehicle and a control allocator (351) for transforming (120) motion requests to actuator instructions, wherein the motion support devices include one or more individually controllable suspension actuators (231, 232, 233, 323) configured to cause dynamic distribution of vertical force among suspension points (411, 412, 413, 421, 422, 423) of the vehicle, and wherein the vehicle is configured to respond to the motion requests by operating (130) the plurality of motion support devices, including the one or more individually controllable suspension actuators, in response to the actuator instructions from the control allocator, the method comprising applying (121), by a processor device (702) of a computer system (290, 700), constraints (501, 502, 503) on lateral and / or longitudinal forces when transforming (120) the motion requests to the actuator instructions, wherein respective lateral and / or longitudinal forces are associated with respective suspension points, and wherein the constraints on lateral and / or longitudinal forces are dynamically varying in dependence on the dynamic distribution of vertical force.

5. The method of claim 4, wherein the dynamic distribution of vertical force is expressed via vertical force variables in a control allocation problem applied to transform the motion requests to the actuator instructions.

6. The method of claim 5, wherein the control allocation problem comprises a component that represents a cost of operating the suspension actuators.

7. The method of any of claims 4-6, wherein the dynamic distribution of vertical force is used, when transforming the motion requests to the actuator instructions, to counteract a variation of external friction conditions among wheels of the vehicle.

8. The method of any of claims 4-7, wherein the dynamic distribution of vertical force is used, when transforming the motion requests to the actuator instructions, to enable allocation of lateral and / or longitudinal forces as required for accomplishing a vehicle manoeuver indicated by the motion requests.

9. The method of any of claims 4-8, further comprising applying (122), by the processor device, a rollover avoidance constraint when transforming (120) the motion requests to the actuator instructions, wherein the rollover avoidance constraint limits the dynamic distribution of vertical force.

10. The method of any of claims 4-9, further comprising applying (123), by the processor device, a tire load constraint when transforming (120) the motion requests to the actuator instructions, wherein the tire load constraint limits the dynamic distribution of vertical force.

11. The method of any of claims 4-10, further comprising: predicting (110), by the processor device, upcoming motion requests, and causing, by the processor device, the control allocator to transform (120) the predicted motion requests to actuator instructions for proactive operation (130) of the suspension actuators.

12. A vehicle (200) comprising the computer system of any of claims 1-3 and / or a processor device configured to perform the method of any of claims 4-11.

13. The vehicle of claim 12, further comprising a plurality of motion support devices (320) configured to actuate the vehicle and a control allocator configured to transform motion requests to actuator instructions, wherein the motion support devices include one or more individually controllable suspension actuators (231, 232, 233, 323) configured to cause dynamic distribution of vertical force among suspension points (411, 412, 413, 421, 422, 423) of the vehicle, and wherein the vehicle is configured to respond to the motion requests by operating the plurality of motion support devices, including the one or more individually controllable suspension actuators, in response to the actuator instructions from the control allocator.

14. A computer program product (800) comprising program code for performing, when executed by a processor device, the method of any of claims 4-11.

15. A non-transitory computer-readable storage medium (800) comprising instructions, which when executed by a processor device, cause the processor device to perform the method of any of claims 4-11.

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