Vehicle motion management based on torque requests with speed limits

Abstract

The application relates to vehicle motion management based on a torque request having a speed limit, in particular a control unit (130, 140) for controlling a heavy vehicle (100), the control unit being arranged to: obtain input data indicative of a desired wheel force (Fx, Fy) to be generated by at least one wheel (210) of the vehicle (100), the control unit (130, 140) is arranged to generate a desired wheel force (Fx, Fy), and to convert the input data into a corresponding equivalent wheel speed or wheel slip rate to be maintained by the wheel (210) based on an inverse tire model (f-1) of the wheel (210) to generate the desired wheel force (Fx, Fy), where the control unit (130, 140) is arranged to obtain the inverse tire model as a function of a current operating condition of the wheel (210), and where the wheel force (Fx, Fy) is determined by the control unit (130, 140). The control unit (130, 140) is arranged to control the heavy vehicle (100) based on the equivalent wheel speed or wheel slip rate and / or based on a wheel speed limit or wheel slip rate limit associated with the equivalent wheel speed or wheel slip rate.

Description

Divisional application

[0001] This application is a divisional application of the Chinese patent application with application number 202080093069.7. The application date of the above-mentioned Chinese patent application is December 4, 2020, and the name of the invention is "Vehicle motion management based on torque request with speed limit". Technical Field

[0002] The present disclosure relates to vehicle motion management, ie, coordinated control of motion support devices such as service brakes and propulsion devices, for heavy vehicles.

[0003] The present invention can be applied to heavy vehicles such as trucks, buses and construction machinery. Although the present invention will be described with respect to cargo transport vehicles such as semi-trailers and trucks, the present invention is not limited to this particular type of vehicle and can also be used in other types of vehicles such as cars. Background Art

[0004] Vehicles are becoming increasingly complex in terms of mechanics, pneumatics, hydraulics, electronics, and software. Modern heavy-duty vehicles may include a variety of different physical devices, such as a combustion engine, an electric motor, friction brakes, regenerative brakes, shock absorbers, air bellows, and a power steering pump. These physical devices are often referred to as motion support devices (MSDs). MSDs can be individually controllable, for example, a friction brake can be applied at one wheel (i.e., negative torque) while another wheel on the vehicle (perhaps even another wheel on the same axle) is simultaneously being used to generate positive torque via the electric motor.

[0005] Recently proposed vehicle motion management (VMM) functions, such as those executed on a central vehicle unit computer (VUC), rely on a combination of MSDs to operate the vehicle to achieve the desired motion effect while maintaining vehicle stability, cost efficiency, and safety. WO2019072379A1 discloses one such example, in which wheel brakes are selectively used to assist heavy vehicles in turning maneuvers.

[0006] A common approach to controlling the various MSDs is to use torque control at the actuator level without any consideration of wheel slip. However, this approach is not without performance limitations. For example, in the event of an excessive wheel slip condition (where one or more wheels are slipping in an uncontrolled manner), safety functions such as traction control and anti-lock braking functions intervene and request a torque override to bring the slip back under control. These safety functions are typically operated by separate control units. If the main control of the actuator and the actuator-related slip control functions are assigned to different control units, the latencies involved in the communication between them may limit the slip control performance. Furthermore, the relevant actuator and slip assumptions made in the multiple control units used to implement slip control may be inconsistent, which in turn may lead to suboptimal performance.

[0007] There is a need for improved vehicle control methods that handle wheel slip in a better manner. Summary of the Invention

[0008] An object of the present disclosure is to provide a control unit and method that facilitate vehicle control based on a slip ratio request or wheel speed request (instead of a conventional torque request), the speed request or slip ratio request being derived based on an improved tire behavior model.

[0009] According to a first aspect, a vehicle motion management system for a vehicle is provided, which is capable of being connected to a motion support system for transmitting control signals between the vehicle motion management system and the motion support system, wherein the vehicle motion management system is configured to determine a desired torque for operating the vehicle under current vehicle operating conditions; determine a wheel slip limit of at least one wheel of the vehicle; determine a wheel speed limit of the at least one wheel of the vehicle based at least on the wheel slip limit; and transmit a control signal indicating the desired torque and the wheel speed limit to the motion support system.

[0010] A vehicle motion management system and a motion support system are control systems of a vehicle, wherein each of these control systems is arranged to perform various control functions for controlling the operation of the vehicle, in particular for controlling the operation of the wheels. According to one example, the vehicle motion management is just the normal driver control input, i.e. the manual steering, acceleration and braking input. The vehicle motion management system is preferably configured to receive and determine higher level wheel parameters, i.e. the vehicle motion management system determines the desired torque and wheel slip limit in a more general form, whereas the motion support system is arranged as a lower level control system which is configured to translate the parameters received from the vehicle motion management system into appropriate parameters for the actuators. The motion support system takes into account the current driveline state before forwarding the actuator signals to the actuators. The current driveline state can for example relate to the current vehicle transmission state, the gear or transmission clutch actuation state of the vehicle transmission.

[0011] The desired torque can for example be received from an operator of the vehicle stepping on an acceleration pedal and / or stepping on a brake pedal. The desired torque can also be received from a system autonomously controlling the vehicle propulsion operation or from an advanced driver assistance system (ADAS).

[0012] To ensure that excessive slip does not occur, in addition to the torque request, two speed limits can be sent to the motor controller: a speed upper limit and a speed lower limit. If the current motor speed is within the range defined by the upper and lower limits, the electric motor shall apply torque as requested in the VMM torque request.

[0013] At a given time step, if the current motor speed is above the upper limit, the motor controller shall decrease the applied motor torque relative to the previous time step. The motor torque shall continue to decrease until the motor speed is below or equal to the speed upper limit. Furthermore, at a given time step, if the motor speed is measured to be below the lower limit, the torque applied to the electric motor shall increase relative to the last time step. The motor torque shall continue to increase until the motor speed is above or equal to the speed lower limit.

[0014] Alternatively, the control can be based on reducing the magnitude of the applied torque without allowing the sign of the applied torque to change.

[0015] The "override" of the torque control can be terminated if the motor speed returns to a value within the range defined by the speed upper and lower limits, or if the VMM torque request received by the motor control is less than the value output from the upper limiter. The "override" of the torque control can also be terminated if the VMM torque request received by the motor control is greater than the value output from the lower limiter.

[0016] The upper and lower speed limits can be calculated based on the current vehicle speed and a longitudinal slip limit, which can be determined based on an inverse tire model, as discussed in more detail below. Thus, according to one example, the speed limits resemble a window of permissible motor or wheel speeds around the current motor or wheel speed. This means that if a road section with reduced friction is encountered, the motor speed can change rapidly without causing excessive wheel slip because the speed limit would be exceeded. Consequently, torque will be adjusted to maintain speed within the permissible range defined by the upper and lower speed limits.

[0017] Please note that all states and speed limits described above should be signed. For example, when "Torque Increase" occurs due to a lower speed limit, this will result in a negative torque value increasing to a smaller negative torque value; or from a positive torque value to a larger positive torque value; or even from a negative value to a positive value. Similar behavior can be implemented for an upper speed limit.

[0018] In addition to (or instead of) speed limits or wheel slip limits, rotational acceleration limits can be sent to the motor controller. These can help prevent the speed limiter or any other motor control function from delivering undesirable torque step changes to the wheels.

[0019] The wheel slip limit should be interpreted as the maximum allowable wheel slip of at least one wheel during operation. Wheel slip is the relative longitudinal motion between the wheels of a vehicle and the ground surface, i.e., the amount of "slip." Wheel slip can be determined as the relationship between the longitudinal wheel speed and the rotational wheel speed, taking into account the wheel radius. Therefore, the wheel speed limit is based on the wheel speed relative to the road surface, as seen in a wheel-based coordinate system. According to an example embodiment, the vehicle motion management system can be configured to determine a current rotational wheel speed and a current longitudinal wheel speed of at least one wheel of the vehicle; and determine the wheel slip of the at least one wheel based on the current rotational wheel speed and the current longitudinal wheel speed.

[0020] The present disclosure is based, at least in part, on the recognition that calculation of wheel slip limits can be performed by a higher-level vehicle motion management system by transmitting a control signal indicative of a desired torque in combination with a wheel speed limit to a motion support system. When calculating wheel slip, the denominator in the wheel slip equation consists of the rotational wheel speed of the wheel. At low vehicle speeds, the denominator is therefore close to zero or approaches zero, which can lead to a source of error when calculating wheel slip. Therefore, performing wheel slip calculation in a higher-level vehicle motion management system is advantageous because potential inconsistencies when calculating wheel slip by a separate motion support system can be avoided. As a result, improved wheel slip consistency is achieved.

[0021] Furthermore, it is particularly advantageous to transmit control signals indicative of a desired torque and a wheel speed limit to the motion support system when operating the vehicle using an electric machine, since the electric machine can be speed and torque controlled. In contrast to slip control, speed control is also easier to implement for e.g. a service brake, since the rotational speed is a common output of the tire torque balancing system and does not include any non-linearities present in the wheel slip ratio equation.

[0022] According to an example embodiment, the wheel speed limit can be further based on the desired torque. Thus, the desired torque, i.e. the torque request, is used to calculate the slip ratio limit, which is the slip ratio limit used when calculating the wheel speed limit.

[0023] According to an example embodiment, the wheel speed limit can comprise a wheel speed upper limit and a wheel speed lower limit. The vehicle motion management system can be further configured to transmit the wheel speed upper limit to the motion support system at least when the desired torque is above zero; and to transmit the wheel speed lower limit to the motion support system at least when the desired torque is below zero.

[0024] One advantage is that different wheel speed limits can be used depending on whether the vehicle is accelerating or decelerating.

[0025] According to an example embodiment, the vehicle motion management system can be further configured to: determine an offset wheel speed parameter; obtain a signal indicative of a wheel speed of the vehicle; and determine a wheel slip ratio limit based on the offset wheel speed parameter when the wheel speed is below a threshold wheel speed limit.

[0026] The offset wheel speed parameter is advantageously used when the wheel speed is relatively low, e.g. close to zero. As described above, it can be difficult to correctly calculate the wheel slip ratio limit at low speeds due to the denominator of the wheel slip ratio calculation model. Thus, setting the offset wheel speed parameter advantageously remedies this potential inconsistency. The offset wheel speed parameter can be an upper offset wheel speed parameter and a lower offset wheel speed parameter, where the upper offset wheel speed parameter is higher than the current vehicle speed and the lower offset wheel speed parameter is lower than the current vehicle speed. The offset wheel speed parameter can be obtained by mapping the offset wheel speed parameter to the desired torque using a tire model.

[0027] According to an example embodiment, the wheel slip ratio limit can be within a predetermined wheel slip ratio range. Thus, the wheels of the vehicle will not be exposed to too severe wheel slip or too low wheel slip ratio.

[0028] According to an example embodiment, the vehicle motion management system may be further configured to obtain a signal indicating the current accelerator pedal position of the vehicle's accelerator pedal; and determine the desired torque based on the current accelerator pedal position. However, according to an example embodiment, the desired torque may alternatively be determined based on a signal received from an autonomous vehicle operating system. According to another alternative as shown above, the vehicle motion management system may also be configured to obtain a signal indicating the brake pedal position used to determine the desired torque, or to obtain a signal from the so-called retarder lever position of the vehicle's retarder. Therefore, the vehicle motion management system can be arranged in autonomously controlled vehicles as well as in driver-controlled vehicles.

[0029] According to an example embodiment, the vehicle motion management system may be further configured to determine a wheel friction level between at least one wheel and the road surface; and determine the current vehicle operating condition based on the determined wheel friction level. Other alternatives exist for determining the current vehicle operating condition. For example, when determining the current vehicle operating condition, the vehicle's current weight (i.e., the weight of a fully loaded vehicle), the road topology on which the vehicle is currently operating, etc. may also be used as input parameters in addition to or in addition to the wheel friction level.

[0030] According to a second aspect, a motion support system for a vehicle is provided, which is capable of being connected to the above-mentioned vehicle motion management system and at least one actuator, the at least one actuator being configured to apply torque to at least one wheel of the vehicle, wherein the motion support system is configured to receive a control signal from the vehicle motion management system, the control signal indicating the desired torque for operating the vehicle under the current vehicle operating conditions and indicating the wheel speed limit of the at least one wheel of the vehicle; determine the current vehicle transmission state of the vehicle; determine the operating torque and the actuator rotation speed limit based on the current vehicle transmission state, the desired torque and the wheel speed limit; and transmit an actuator signal to the actuator so that the actuator generates the operating torque on the at least one wheel without exceeding the actuator rotation speed limit.

[0031] The current drivetrain state should be interpreted as the current operating mode of the drivetrain (particularly the transmission of the drivetrain). According to an exemplary embodiment, the current vehicle drivetrain state can be one of the following: the current vehicle transmission state, the gear position of the vehicle transmission, or the transmission clutch actuation state. Thus, as indicated above, the motion support system is arranged as a lower-level control system that is configured to convert parameters received from the vehicle motion management system into appropriate parameters for the actuators, taking into account the current drivetrain state.

[0032] According to an example embodiment, the wheel motion system may be a decentralized wheel motion system connectable to wheel-specific actuators configured to control a single wheel of the vehicle.

[0033] The use of decentralized wheel motion systems enables a fast response of the dedicated actuators to which they are connected, thereby improving the vehicle's operational propulsion / braking performance. Decentralized wheel motion systems can be connected to individual vehicle motion management systems, or to a central vehicle motion management system that is connected to multiple decentralized wheel motion systems.

[0034] The other effects and features of the second aspect are largely similar to those described above with respect to the first aspect. Therefore, through the above-mentioned first and second aspects, a vehicle control system is provided, which includes the vehicle motion management system defined by any embodiment of the first aspect and the motion control system defined by any embodiment of the second aspect.

[0035] According to a third aspect, a method for controlling an actuator of a vehicle is provided, the actuator being configured to apply torque to at least one wheel of the vehicle, wherein the method comprises: determining a desired torque for operating the vehicle under current vehicle operating conditions; determining a wheel slip limit for said at least one wheel of the vehicle; determining a wheel speed limit for said at least one wheel of the vehicle based at least on the wheel slip limit; determining an operating torque and an actuator rotational speed limit based on the desired torque, the wheel speed limit and the current vehicle driveline state; and controlling the actuator to generate the operating torque on said at least one wheel without exceeding the actuator rotational speed limit.

[0036] The effects and features of the third aspect are largely similar to those described above with respect to the first and / or second aspects. Therefore, the features described above with respect to the vehicle motion management system and motion support system are applicable to the method described in the third aspect.

[0037] According to a fourth aspect, a control signal is provided, which represents an instruction to be executed by a motion support system, the control signal including: a torque component that enables the motion support system to determine an operating torque; and a wheel speed limit component that represents wheel speed limit data that, when executed by the motion support system, causes the motion support system to generate an actuator signal corresponding to the operating torque subject to an actuator rotation speed limit, the actuator rotation speed limit being capable of being determined based on the wheel speed limit component while taking into account a current vehicle transmission system state.

[0038] According to a fifth aspect, there is provided a computer program comprising program code components for performing the steps of the third aspect when the program is run on a computer.

[0039] According to a sixth aspect, a computer-readable medium carrying a computer program is provided. The computer program includes a program component. When the program component is run on a computer, the program component is used to perform the steps of the third aspect above.

[0040] According to one example of the method, the VMM (Vehicle Motion Management) sends a torque request to the electric machine, which may, for example, represent a torque request from a driver's accelerator pedal (positive torque request) or it may be a request representing a brake torque request (negative torque request).

[0041] The object is also achieved, at least in part, by a control unit for controlling a heavy vehicle. The control unit is arranged to obtain input data indicating a desired wheel force to be generated by at least one wheel of the vehicle and convert the input data into a corresponding equivalent wheel speed (or equivalently, motor speed) or wheel slip to be maintained by the wheel, so as to generate the desired wheel force based on an inverse tire model of the wheel. The control unit is arranged to obtain the inverse tire model based on the current operating condition of the wheel and control the heavy vehicle based on the equivalent wheel speed or wheel slip.

[0042] Therefore, rather than requesting torque from different actuators as is typically done, wheel slip limit requests are sent to the wheel torque actuators at the wheel ends, which are then tasked with maintaining operation below the requested wheel slip limit. In this way, MSD control is moved closer to the wheel ends, enabling higher bandwidth control due to reduced control loop latency and faster processing available closer to the wheel ends. Consequently, the MSD can react more quickly to changes in, for example, road friction, and thus provide more stable wheel forces under variable operating conditions. Compared to traditional torque-based control, this MSD control scheme improves both the startability of heavy vehicles and maneuverability in higher-speed driving scenarios. For example, if a wheel temporarily leaves the ground or experiences significantly reduced vertical force due to a bump in the road, the wheel will not spin uncontrollably. Instead, MSD control will quickly reduce the applied torque to maintain the wheel slip at the requested value (i.e., below the slip limit) so that when the wheel re-contacts the ground, the appropriate wheel speed is maintained.

[0043] Another advantage is adapting the inverse tire model to account for changes in the current wheel operating conditions, as this improves the accuracy and robustness of the mapping between the expected wheel forces and the equivalent wheel speeds or wheel slips. Thus, as the operating conditions change, the inverse tire model is adapted to better model the current operating conditions. Therefore, when the operating conditions of a given wheel change, the mapping between wheel forces and wheel slips (or wheel speeds) also changes to compensate for the change in operating conditions.

[0044] In addition to wheel slip or wheel speed, the control unit can also be arranged to assign (i.e., request) a steering angle to be maintained at one or more steered wheels on the vehicle. This steering angle will have an impact on the lateral wheel slip. Therefore, jointly processing steering and wheel torque (slip or speed) is generally an advantage, as it generally improves overall vehicle control in terms of robustness and efficiency.

[0045] According to some aspects, the data indicative of desired wheel forces includes desired wheel torque and wheel rolling radius. This means that the inverse tire model interface can accommodate functions that output requested torque, such as traditional vehicle control functions, which represent or indicate desired wheel forces along with wheel radius.

[0046] According to some aspects, current operating conditions include a vehicle or wheel-to-ground velocity vector. Knowing the wheel-to-ground velocity allows the rotational speed of the wheel to be controlled to maintain a desired wheel slip ratio. The wheel-to-ground velocity also affects the mapping between wheel force and wheel slip ratio. For example, the contact patch between the ground and the wheel may change as the vehicle speed changes.

[0047] According to some aspects, the current operating conditions include the normal load on the wheel, or the vertical force acting on the wheel. The normal load for a given wheel, along with the coefficient of friction, determines the maximum achievable wheel force. Therefore, the inverse tire model is preferably adjusted to account for variations in the normal load. By measuring or otherwise determining the normal load, the inverse tire model can be made more accurate.

[0048] According to some aspects, the current operating conditions include an estimated or otherwise determined tire stiffness for the wheel. Tire stiffness has a greater impact on the inverse tire model in the linear range of low to medium tire slip. By accounting for variations in tire stiffness, a more accurate inverse tire model can be derived. Optionally, the tire stiffness is corrected for factors specific to the tire on a given wheel (e.g., wear, age, temperature, inflation pressure, etc.). The tire stiffness can be solely the longitudinal slip stiffness, which can be used as a basis for proportionally adjusting the lateral slip stiffness, or a vector comprising both longitudinal and lateral slip stiffnesses.

[0049] According to some aspects, the current operating conditions include a tire road friction coefficient associated with the wheel. Among other factors, the tire road friction coefficient has an impact on the mapping between wheel force and wheel slip ratio, as it has an impact on the maximum achievable tire force. The estimated road friction parameter can be used to adapt the tire force curve to limit the allowed peak force, or to change the peak force slip ratio position of the inverse tire model.

[0050] According to some aspects, the current operating conditions include a minimum required lateral force of the wheel. This means that the given wheel's minimum lateral force generation capability can be required to operate. For example, if the vehicle is turning, a certain amount of lateral force can need to be generated in order to successfully complete the turn. Due to the requirement for lateral force, the wheel speed can need to be limited to a wheel slip ratio that is lower than the requested wheel slip ratio. Similarly, the current operating conditions optionally include a maximum allowed lateral slip angle of the wheel. With the minimum required lateral force and the maximum allowed lateral slip angle, the generated longitudinal slip request is limited to a search space in which the maximum allowed lateral slip angle guarantees the minimum lateral force capability. Although both are optional arguments, they can be advantageously used to request longitudinal force in a safe way that does not cause problems such as yaw instability. The vehicle controller can use the minimum required lateral force parameter to make sure that there is still enough lateral force capability to be able to pass a given path with a certain acceleration profile and curvature profile. The maximum longitudinal speed of the vehicle throughout a maneuver is typically limited by roll stability and road friction. To know how large a range of lateral acceleration the vehicle unit can support through a turning maneuver, it can be necessary to know the lateral force capability. It is therefore an advantage to be able to specify a minimum required lateral force capability.

[0051] The vehicle controller can use the maximum allowed lateral slip angle to make sure that the yaw moment balance or the vehicle's sideslip is maintained at an acceptable level consistent with the maneuver to be performed. This feature is particularly beneficial in autonomous or functionally safety critical applications where it is desirable to keep the tires operating within their linear combined slip ratio range, thereby preventing any traction control or yaw stability intervention that can lead to unpredictable effects.

[0052] According to some aspects, the inverse tire model is configured to provide a residual lateral force capability of the wheel. The residual lateral force capability can be used to adjust the boundaries of the requests sent to the wheel end, or as feedback to the control allocator to adapt its control requests to increase the lateral force capability of the wheel if it is too low for the current driving scenario.

[0053] According to some aspects, the inverse tire model is configured to provide the desired wheel force gradient for the tire operating point and the current operating conditions of the wheel, which are associated with the desired wheel force. This output can be used to custom tune the gains of the velocity controllers in the actuators, for example, based on the priorities of the control distributor. For example, if the vehicle is turning and the lateral gradient value is high, this indicates poor velocity control performance that degrades lateral cornering performance, so the velocity controller gains can be adjusted to mitigate this issue. Knowing the gradient also facilitates stability and control robustness analysis, which is an advantage.

[0054] According to some aspects, the control unit is arranged to store a predetermined inverse tire model in a memory, wherein the inverse tire model is stored in the memory as a function of the current operating conditions of the wheel. This means that the control unit has access to a range of different models and can select a suitable model from this range of models.

[0055] According to some aspects, the control unit is arranged to adapt the inverse tire model based on measured wheel behavior and / or vehicle behavior in response to controlling the heavy vehicle based on equivalent wheel speed or wheel slip. Advantageously, the control unit thus monitors the actual response of the wheels (and possibly the vehicle) and adjusts the inverse tire model accordingly. This means that the control method becomes less sensitive to assumptions about vehicle performance in different scenarios or the impact of different parameters on vehicle controllability. Furthermore, if operating conditions change in unexpected ways, the inverse tire model will adapt to these changes, thereby providing robust control even in scenarios not yet encountered.

[0056] According to some aspects, the inverse tire model is adapted to consistently lie within predetermined upper and / or lower limits for wheel forces, based on wheel slip or wheel speed. This means that model adaptation of the inverse tire model is permitted, but only within certain predetermined boundaries. Thus, the one or more boundaries represent a safeguard against unforeseen errors during the model adaptation process. An example of an adaptive inverse tire model is an artificial neural network that is continuously or at least regularly trained based on control inputs and actual wheel responses or vehicle responses to the control inputs.

[0057] Also disclosed herein are a computer program, a computer-readable medium, a computer program product, and a vehicle associated with the advantages discussed above.

[0058] In general, all terms used in the claims should be interpreted according to their ordinary meanings in the technical field, unless otherwise clearly defined herein. Unless otherwise clearly stated, all references to "one / an / the element, device, part, means, step, etc." should be openly interpreted as referring to at least one instance of the element, device, part, device, step, etc. Unless clearly stated, the steps of any method disclosed herein do not have to be performed in the exact order disclosed. When studying the appended claims and the following description, the other features and advantages of the present invention will become apparent. Those skilled in the art will recognize that, without departing from the scope of the present invention, the different features of the present invention can be combined to produce embodiments other than those described below.

[0059] It should also be understood that even if some features are discussed separately from other features, all features discussed herein can be advantageously implemented and used to control the same vehicle. Therefore, the various features, algorithms, and devices disclosed herein should be considered in combination as well as separately from each other. BRIEF DESCRIPTION OF THE DRAWINGS

[0060] With reference to the accompanying drawings, the following is a more detailed description of embodiments of the invention cited as examples. In these drawings:

[0061] Figure 1 An example heavy vehicle is shown;

[0062] Figure 2 schematically illustrates a movement support device arrangement;

[0063] Figure 3 The vehicle control functions are shown;

[0064] Figure 4 is a graph showing tire force as a function of wheel slip;

[0065] Figure 5 The adaptation of the wheel behavior model to the measured data is shown;

[0066] Figure 6 An example motion support device control system is shown;

[0067] Figure 7 is a flow chart illustrating a method;

[0068] Figure 8 A control unit is schematically shown;

[0069] Figure 9 An example computer program product is shown;

[0070] Figure 10Shows a road scene with a large difference in friction between the left and right wheels (split friction);

[0071] Figures 11 to 14 is a flow chart illustrating a method;

[0072] Figure 15 A tire is shown; and

[0073] Figures 16 to 18 is a flow chart illustrating the method. DETAILED DESCRIPTION

[0074] The present invention will now be described more fully hereinafter with reference to the accompanying drawings, in which certain aspects of the invention are shown. However, the present invention can be embodied in many different forms and should not be construed as limited to the embodiments and aspects set forth herein; rather, these embodiments are provided by way of illustration so that this disclosure will be thorough and complete and will fully convey the scope of the invention to those skilled in the art. Throughout the specification, like reference numerals refer to like elements.

[0075] It should be understood that the present invention is not limited to the embodiments described herein and shown in the drawings; rather, those skilled in the art will recognize that many modifications and variations are possible within the scope of the appended claims.

[0076] Figure 1 An example vehicle 100 for transporting freight is shown, in which the techniques disclosed herein can be advantageously applied. Vehicle 100 includes a tractor or towing vehicle 110 supported on front wheels 150 and rear wheels 160, at least some of which are driven wheels. Typically, but not necessarily, all wheels on the tractor are braked wheels. Tractor 110 is configured to tow a first trailer unit 120 supported on trailer wheels 170 via a fifth wheel connection in a known manner. The trailer wheels are typically braked wheels, but may also include driven wheels on one or more axles.

[0077] It will be appreciated that the methods and control units disclosed herein may also be advantageously applied to other types of heavy vehicles, such as trucks with drawbar connections, construction equipment, buses, etc. The present disclosure proposes various complementary techniques, methods, and control units for controlling a heavy vehicle based at least in part on the relationship between wheel forces and wheel slip, as recited in the accompanying list of claims.

[0078] The tractor 110 includes a vehicle unit computer (VUC) or control unit 130 for controlling various functions, namely, propulsion, braking, and steering. Some trailer units 120 also include a VUC or control unit 140 for controlling various trailer functions, such as braking and, in some cases, propulsion of the trailer wheels. The VUCs 130 and 140 can be centralized or distributed across several processing circuits. Some of these vehicle control functions can also be performed remotely, for example, on a remote server 190 connected to the vehicle 100 via a wireless link 180 and a wireless access network 185.

[0079] The VUC 130 on the tractor 110 (and possibly the VUC 140 on the trailer 120 ) may be configured to execute a vehicle control method organized according to a hierarchical functional architecture, where some functions may be included in a higher-level Traffic Situation Management (TSM) domain and some other functions may be included in a lower-level Vehicle Movement Management (VMM) domain.

[0080] Figure 2 A schematic diagram illustrates functionality 200 for controlling wheels 210 via several exemplary MSDs or actuators, here including friction brakes 220 (e.g., disc brakes or drum brakes) and propulsion devices 250. Friction brakes 220 and the propulsion devices are examples of wheel torque-generating devices, which may also be referred to as actuators and may be controlled by one or more motion support device control units 230. This control is based on measurement data obtained, for example, from wheel speed sensors 240 and other vehicle state sensors 280 (e.g., radar sensors, lidar sensors, and vision-based sensors such as cameras and infrared detectors). Other exemplary torque-generating motion support devices that can be controlled according to the principles discussed herein include engine retarders and power steering devices. The MSD control unit 230 can be configured to control one or more actuators. For example, it is not uncommon for the MSD control unit 230 to be configured to control two wheels on an axle.

[0081] Herein, the terms “MSD controller,” “MSD control function,” “motion support system,” “actuator control system,” and “wheel motion system” may be used interchangeably with the term “MSD control unit.”

[0082] The TSM function 270 plans driving maneuvers with a time span of, for example, about 10 seconds. This time span corresponds to, for example, the time required for the vehicle 100 to negotiate a curve. The vehicle maneuvers planned and executed by the TSM may be associated with acceleration profiles and curvature profiles that describe the desired vehicle speed and turning for the given maneuver. The TSM continuously requests the desired acceleration profiles from the VMM function 260. req and curvature distribution diagram c req The VMM function 260 performs force allocation to satisfy requests from the TSM in a safe and robust manner. The VMM function 260 continuously feeds capability information back to the TSM function, detailing the vehicle's current capabilities in terms of, for example, force, maximum speed, and achievable acceleration.

[0083] The acceleration profile and curvature profile can also be obtained from the driver of the heavy vehicle via normal control input devices such as the steering wheel, accelerator pedal, and brake pedal. The source of the acceleration profile and curvature profile is beyond the scope of this disclosure and will not be discussed in further detail herein. Advanced VMM functionality can be combined with traditional manual driver control inputs to form an advanced driver assistance system (ADAS).

[0084] Reference is also made to the diagram showing the vehicle control function 300. Figure 3 , the VMM function 260 operates in a time span of about 1 second and continuously generates the acceleration profile a req and curvature distribution diagram c req These are translated into control commands for controlling vehicle motion functions, which are actuated by the various MSDs 220, 250 of vehicle 100. These MSDs 220, 250 report capability information 321a-321c to the VMM, which in turn is used as constraints in vehicle control. The VMM function 260 performs vehicle state or motion estimation 305. This involves monitoring operation using various sensors 306 located throughout vehicle 100, typically (but not always) connected to the MSDs 220, 250. The VMM function 260 continuously determines the vehicle state s, including the position, velocity, acceleration, and articulation angles of the various units in the vehicle complex.

[0085] The result of the motion estimation 305 (ie, the estimated vehicle state s) is input to the force generation module 310, which determines the global forces V = [V1, V2] required for the different vehicle units to move the vehicle 100 according to the requested acceleration profile a. req and curvature distribution diagram c reqThe desired global force vector V is input to the MSD coordination function 320, which distributes the wheel forces and coordinates other MSDs (such as steering and suspension). The coordinated MSDs then work together to provide the desired lateral force Fy and longitudinal force Fx, as well as the required moment Mz, on the vehicle unit to achieve the desired motion of the vehicle combination 100.

[0086] By determining the vehicle unit motion using, for example, a global positioning system, vision-based sensors, wheel speed sensors, radar sensors and / or lidar sensors and converting the vehicle unit motion to the local coordinate system of a given wheel 210 (e.g., in terms of longitudinal velocity component and lateral velocity component), the wheel slip rate can be accurately estimated in real time by comparing the vehicle unit motion in the wheel reference coordinate system with data obtained from the wheel speed sensor 240 (which is arranged to be connected to the wheel 210).

[0087] Will be combined below Figure 4 The tire model discussed in more detail in

[15] can be used to calculate the desired tire longitudinal force Fx for a given wheel i. i The equivalent wheel slip ratio λ of the wheel i . Wheel slip λ is related to the difference between the wheel rotational speed and the ground speed and is discussed in more detail below. Wheel speed ω is the rotational speed of the wheel, given in units such as revolutions per minute (rpm) or angular velocity expressed in radians per second (rad / s) or degrees per second (deg / s).

[0088] Here, a tire model is a wheel behavior model that describes the wheel forces generated in the longitudinal direction (rolling direction) and / or lateral direction (orthogonal to the longitudinal direction) as a function of wheel slip. Hans Pacejka introduces the basics of tire models in "Tire and Vehicle Dynamics" (Elsevier, 2012, ISBN 978-0-08-097016-5). For example, see Chapter 7, which discusses the relationship between wheel slip and longitudinal force.

[0089] In summary, the VMM function 260 manages the force generation and MSD coordination. That is, it determines what forces are required at the vehicle units to satisfy the requests from the TSM function 270, such as accelerating the vehicle according to the requested acceleration profile requested by the TSM and / or also generating a certain curvature motion of the vehicle requested by the TSM. These forces may include, for example, a yaw moment Mz, longitudinal forces Fx and lateral forces Fy, as well as different types of torque to be applied to different wheels.

[0090] The interface 265 between the VMM and the MSDs, which enables torque to be delivered to the vehicle's wheels, has traditionally focused on torque-based requests from the VMM to each MSD, without any consideration of wheel slip. However, this approach has significant performance limitations. If a safety-critical or excessive slip condition occurs, the relevant safety functions (traction control, anti-lock braking, etc.), running on separate control units, typically intervene and request a torque override to bring the slip back under control. The problem with this approach is that because the main control of the actuators and the slip control of the actuators are assigned to different electronic control units (ECUs), the time delay involved in the communication between them significantly limits the slip control performance. Furthermore, the relevant actuators and slip assumptions in the two ECUs used to implement the actual slip control may not be consistent, which in turn can lead to suboptimal performance.

[0091] Instead, significant benefits can be achieved by using wheel speed or wheel slip based requests on the interface 265 between one or more VMMs and the MSD controller 230, thereby shifting the difficult actuator speed control loop to the MSD controller, which typically operates with a much shorter sampling time than the VMM function. Such an architecture can provide better disturbance rejection than a torque-based control interface, thereby improving the predictability of the forces generated at the tire-road contact patch.

[0092] refer to Figure 3 The inverse tire model function block 330 converts the required wheel force Fx determined by the MSD coordination function block 320 for each wheel or subset of wheels. i 、 Fy i Convert to equivalent wheel speed ω wi Or wheel slip λ i These wheel speeds or wheel slips are then sent to the corresponding MSD controllers 230. The MSD controllers report back capabilities 231a-231c which can be used as constraints in the MSD coordination function block 320, for example.

[0093] According to SAE J670 (SAE Vehicle Dynamics Standards Committee, January 24, 2008), longitudinal wheel slip It can be defined as:

[0094] in, is the effective wheel radius in meters, is the angular velocity of the wheel, and is the longitudinal velocity of the wheel (in the wheel's coordinate system). Therefore, The value ranges from -1 to 1 and quantifies the degree to which a wheel is slipping relative to the road surface. Wheel slip is essentially the speed difference between the wheel and the vehicle. Therefore, the techniques disclosed herein are applicable to any type of wheel slip definition. It will also be understood that, in the wheel's coordinate system, a wheel slip value is equivalent to a wheel speed value for a given wheel's speed on the surface.

[0095] The VMM 260 (and optionally the MSD control unit 230) maintains information about (in the wheel's reference frame), the wheel speed sensor 240 etc. can be used to determine (Rotational speed of the wheel).

[0096] In order for a wheel (or tire) to generate wheel forces, slip must occur. For small slip values, the relationship between slip and generated force is approximately linear, with the proportionality constant often expressed as the tire's slip stiffness. The tire 210 is subjected to a longitudinal force F x , lateral force F y and the normal force F z Normal force F Z It is the key to determine some important vehicle properties. For example, the normal force largely determines the longitudinal tire force F that can be achieved by the wheel. x , because: Under normal circumstances, ,in is the coefficient of friction associated with the road friction conditions. The maximum available lateral force for a given longitudinal slip ratio can be described by the so-called Magic Formula, as described by Hans Pacejka in "Tyre and Vehicle Dynamics" (Elsevier, 2012, ISBN 978-0-08-097016-5).

[0097] Instead of requesting wheel slip or wheel speed directly from the MSD, a torque request with a speed limit interface can be used. The torque request is then allowed to influence wheel behavior as long as the wheel speed remains between the upper and lower wheel speed limits. The wheel slip or wheel speed limits can be configured to achieve a given force based on the desired wheel slip described above, or they can be configured with a margin to the desired wheel slip or wheel speed.

[0098] To ensure excessive slip does not occur, two speed limits can be sent to the motor controller in addition to the torque request: an upper speed limit and a lower speed limit. Some example embodiments may only use the upper speed limit. From a functional perspective, wheel speed limits can be considered equivalent to motor speed limits. Similarly, in a given wheel's reference frame, given the current vehicle ground speed, wheel or motor speed limits can be converted into wheel slip limits.

[0099] If the current motor speed is within the range defined by the upper and lower limits, the electric motor should apply torque according to the torque requested in the VMM torque request. It is recognized that wheel speed and motor speed are closely related. If the electric motor is connected to one or more wheels via a transmission, the transmission determines the conversion between motor speed and wheel speed. If the wheels are connected to the electric motor via a differential, torque and wheel speed are distributed to the wheels in a known manner.

[0100] At a given time step, if the current motor speed is above the upper speed limit, the motor controller operates to reduce the applied motor torque relative to the previous time step. This causes the wheel speed to decrease and eventually fall below the configured wheel speed limit. The motor torque should continue to decrease until the motor speed is below or equal to the upper speed limit. Additionally, at a given time step, if the motor speed is measured to be below the lower speed limit, the torque applied to the motor should increase relative to the last time step. This causes the wheel speed to increase. The motor torque should continue to increase until the motor speed is above or equal to the lower speed limit. Other ways of implementing the actual control could be to use a variable step size for the torque control, or to switch to wheel speed control if the wheel speed or wheel slip exceeds the configured limits.

[0101] The methods disclosed herein do not necessarily implement control in discrete time steps. Therefore, instead, if the current motor speed (or wheel speed) is detected to be above a configured upper limit, the motor controller continuously reduces the applied motor torque in a controlled manner while observing the motor speed and / or wheel speed. The motor torque should continue to decrease until the motor or wheel speed is below or equal to the upper speed limit. Furthermore, if the motor speed (or wheel speed) is detected to be below a lower speed limit, the torque applied to the motor is continuously increased. The motor torque should continue to increase until the motor speed is above or equal to the lower speed limit.

[0102] Alternatively, the control may be based on reducing the magnitude of the applied torque without allowing the sign of the applied torque to change.

[0103] This "override" of torque control can be terminated if the motor speed returns to a value within the range defined by the upper and lower speed limits, or if the VMM torque request received by the motor controller is less than the value output from the upper speed limiter. This "override" of torque control can also be terminated if the VMM torque request received by the motor controller is greater than the value output from the lower speed limiter.

[0104] The upper and lower speed limits may be calculated based on the current vehicle speed and a longitudinal slip limit, which may be determined based on an inverse tire model, as will be discussed in greater detail below.

[0105] Note that all of the states and speed limits described above are signed values. Also note that, for example, when a "torque increase" occurs due to a lower speed limit, this will result in a negative torque value increasing to a less negative value; or a positive torque value increasing to a more positive value; or even a negative value increasing to a positive value. Similar behavior can be implemented for the upper speed limit.

[0106] In addition to (or instead of) speed limits or wheel slip limits, rotational acceleration limits can also be sent to the motor controller. These can help prevent the speed limiter or any other motor control function from delivering undesirable torque step changes to the wheels. Of course, wheel slip limits can also be used, as explained in more detail below.

[0107] The upper and lower speed limits can be calculated based on the current vehicle speed and a longitudinal slip limit, which can be determined based on an inverse tire model, as discussed in more detail below. Thus, according to one example, the speed limits act like a window of permissible motor or wheel speeds around the current motor or wheel speed. This means that if a road section with reduced friction is encountered, the motor speed can change rapidly without causing excessive wheel slip because the speed limit will be exceeded, and the torque will be adjusted to maintain the speed within the permissible range defined by the upper and lower speed limits.

[0108] Note that all states and speed limits described above should be signed. For example, when "Torque Increase" occurs due to a lower speed limit, this will result in a negative torque value increasing to a less negative value; or a positive torque value increasing to a more positive value; or even a negative value increasing to a positive value. Similar behavior can be implemented for an upper speed limit.

[0109] Figure 4is a graph showing an example of achievable tire forces as a function of wheel slip. The longitudinal tire force Fx exhibits a portion 410 that increases almost linearly for small wheel slips, followed by a portion 420 that exhibits more nonlinear behavior for larger wheel slips. Even at relatively small longitudinal wheel slips, the achievable lateral tire force Fy decreases rapidly. It is desirable to maintain vehicle operation in the linear region 410 where the achievable longitudinal force in response to an applied braking command is more predictable and where sufficient lateral tire forces can be generated if required. To ensure operation in this region, a wheel slip limit λ of, for example, approximately 0.1 may be imposed on a given wheel. LIM For larger wheel slip ratios (e.g., above 0.1), a more nonlinear region 420 can be seen. Controlling the vehicle in this region can be difficult, so increases are often avoided. This is of concern for traction in conditions such as off-road conditions (where a larger slip ratio limit for traction control may be preferred), rather than for on-road operation.

[0110] This type of tire model can be used by the VMM 260 to generate a desired tire force at a particular wheel. Instead of requesting a torque corresponding to the desired tire force, the VMM can convert the desired tire force into an equivalent wheel slip (or equivalently, into wheel speed relative to ground speed) and request that slip. The main advantage is that the MSD control device 230 will be able to calculate the desired tire force by using the vehicle speed. and wheel rotation speed Operation is maintained at the desired wheel slip ratio while delivering the requested torque at a much higher bandwidth.

[0111] The control units 130, 140 may be arranged to store a predetermined inverse tire model f in a memory. -1(e.g., as a lookup table). The inverse tire model is arranged to be stored in memory as a function of the current operating condition of wheel 210. This means that the behavior of the inverse tire model is adjusted according to the vehicle's operating condition, resulting in a more accurate model compared to a model that does not take the operating condition into account. The model stored in memory can be determined based on experiments and trials, or based on analytical derivation, or a combination of both. For example, the control unit can be configured to access a set of different models selected based on the current operating condition. One inverse tire model can be tailored for high-load driving with large normal forces, another for slippery road conditions with low road friction, and so on. The selection of the model to be used can be based on a set of predetermined selection rules. The model stored in memory can also be at least partially a function of the operating condition. Thus, the model can be configured to take, for example, normal force or road friction as input parameters, thereby deriving an inverse tire model based on the current operating condition of wheel 210. It will be appreciated that many aspects of the operating condition can be approximated by default operating condition parameters, while other aspects of the operating condition can be roughly categorized into a smaller number of categories. Therefore, obtaining an inverse tire model based on the current operating condition of wheel 210 does not necessarily require storing a large number of different models or complex analytical functions that can account for variations in operating conditions at a fine-grained level. Instead, selecting two or three different models based on the operating conditions may be sufficient. For example, one model could be used when the vehicle is heavily loaded, while another model could be used in other situations. In all cases, the mapping between tire forces and wheel slip will vary in some way depending on the operating conditions, which improves the accuracy of the mapping.

[0112] The inverse tire model can also be implemented at least in part as an adaptive model that is configured to automatically or at least semi-automatically adapt to the current operating conditions of the vehicle. This can be achieved by continuously monitoring the response of a given wheel in terms of the wheel forces generated in response to a given wheel slip request, and / or monitoring the response of the vehicle 100 in response to the wheel slip request. The adaptive model can then be adjusted to more accurately model the wheel forces obtained in response to the given wheel slip request for the wheel.

[0113] Figure 5 5 is a graph 500 showing an inverse tire model that maps longitudinal tire force Fx to wheel slip. Also plotted are measured values ​​510 of pairs (F, λ) of wheel slip and corresponding tire force F. According to some aspects, the control unit disclosed herein is arranged to adapt the inverse tire model f based on measured wheel behavior and / or vehicle behavior in response to controlling the heavy vehicle 100 based on equivalent wheel speed or wheel slip. -1. One such type of measurement is the resistance encountered by the motor when it attempts to produce a specific wheel speed. This "torque state" output signal of the motor can be directly converted to an equivalent wheel force via the effective wheel radius R. Wheel force samples can also be obtained from the VMM function as part of the force distribution process. For example, if the VMM notices that too little longitudinal force is consistently obtained in response to a given requested wheel slip, the model can be adjusted to account for the discrepancy, such as by scaling it to better match the desired wheel force. In this case, note that the inverse tire model does not need to be correct in an absolute reference frame, i.e., the inverse tire model is able to accurately predict the forces (in Newtons) produced for a given wheel slip. Instead, it is sufficient if the inverse tire model allows the VMM function 260 to successfully control the vehicle. Notably, by adjusting the inverse tire model in this way based on the measured wheel forces in response to wheel slip requests, other characteristics of the vehicle are automatically included in the modeling to more accurately represent the mapping between wheel slip and wheel forces.

[0114] In the first example of adapting the inverse tire model, sample pairs (F, λ) of the generated force F and the current wheel slip λ are continuously obtained. The generated force F (longitudinal force Fx and lateral force Fy) and the yaw moment Mz can be determined based on vehicle behavior (i.e., a Newton's Second Law type relationship), where the mass m and acceleration a can both be measured using basic sensor technology along with the current wheel slip.

[0115] The inverse tire model is then continuously updated to fit the current measurement results. For example, a Kalman filter can be applied to track the coefficients of the polynomial model {c i}, the polynomial model can then be used as an inverse tire model. Polynomial fitting can also be performed to fit the measurement data 510 to a model, which can then be used as an inverse tire model.

[0116] In a second example, a neural network or other form of AI-based approach is applied to continuously update the inverse tire model. For example, the network is trained using sample pairs (F, λ) of the generated force F and the current wheel slip λ. The network's inputs can be, for example, vehicle load, tire specifications, and road conditions, such as friction. The output can be a set of coefficients for a polynomial model that can be used as a representation of the inverse tire model.

[0117] It will be appreciated that this model adaptation need not be performed onboard vehicle 100. Instead, the measurement data can be uploaded to a remote server 190, which is tasked with finding a suitable model for controlling the vehicle based on wheel slip rather than torque request. This model can then take into account measurement data from more than one vehicle (perhaps a group of vehicles of the same type) or the operational design domain. The model or set of models can then be fed back from remote server 190 to the vehicle for use in controlling vehicle 100.

[0118] The entire inverse tire model can of course also be implemented as a neural network, which is trained during different types of operating conditions. Then, as the operating conditions of the heavy vehicle change, the inverse tire model also changes, so that the corresponding wheel slip ratio for a given wheel force changes over time, which is an advantage.

[0119] Inverse tire model f -1 Adjustments can also be made based on wheel slip or wheel speed to always be within predetermined upper and lower limits for the wheel force. These limits can be obtained, for example, as statistical limits derived from the measurement data 510. For example, upper limits 520 and lower limits 530 can be set to constrain the inverse tire model to within one or two standard deviations from the mean, etc.

[0120] Safety margins can also be applied to the adaptation itself, i.e., constrained adaptation can be performed where the inverse tire model is not allowed to deviate outside a fenced region around a certain nominal model curve. This fenced region can be predetermined or adjusted based on the operating conditions, or through a predefined dynamic driving task (DDT) over a known operational design domain (ODD), which reduces the amount of validation and verification required.

[0121] Reference again Figure 2 , the MSD control unit 230 can be configured to control one or more MSDs associated with the wheels 210. The one or more MSDs may include at least one service brake 220, which is arranged to generate negative torque through the wheels 210, and a propulsion unit 250, wherein the at least one service brake 220 is arranged to generate negative torque through the wheels 210, and the propulsion unit 250 is arranged to generate positive torque and / or negative torque of the wheels 210, such as an electric motor and / or a combustion engine. Other torque-generating devices that can be controlled by the MSD control unit include an engine retarder and a power steering device. The MSD control unit 230 is communicatively coupled to the VMM unit 260 for receiving control commands including wheel speed and / or wheel slip rate requests from the VMM unit 260 to control vehicle movement through the one or more MSDs.

[0122] It will be appreciated that the MSD control unit discussed herein may also be configured to control one or more MSDs associated with wheels other than wheel 210, such as an MSD for controlling the wheels of a given axle, or the wheels on one side of a trailer unit, or all wheels of a trailer unit. Figure 6 Schematically, a system of MSD control units 230a-230f is shown, arranged to control the respective wheels 210a-210f based on control signals received from a central VMM unit 260. One or more additional vehicle units, such as one or more trailers 120, which may be connected via a dolly unit, may also be controlled in this manner. In this case, there may be more than one VMM function, one of which may be designated as the master role, while the other VMM functions may be configured to operate in a slave mode.

[0123] In summary, the VMM function 260 performs force distribution to meet a specific acceleration profile and / or curvature profile. The force is converted into an equivalent wheel slip (or wheel rotational speed), and this slip or speed (instead of a classic torque request) is sent to the MSD control unit 230. The conversion from the desired force to the equivalent slip or wheel rotational speed is based on the inverse tire model. The inverse tire model is not only a function of the requested wheel torque or wheel force, but also takes into account the current operating scenario in which the vehicle 100 is currently operating. According to an example embodiment, the inverse tire model used to control the vehicle 100 is given by:

[0124] in

[0125] - Torque request at the wheels

[0126] - Longitudinal ground speed

[0127] - Lateral ground speed

[0128] - Normal load on the wheel

[0129] -Wheel rolling radius

[0130] - estimated tire stiffness of the wheel (optionally, lateral tire stiffness and longitudinal tire stiffness Any of

[0131] - Estimated tire-road friction at the wheel

[0132] -Minimum required lateral force capacity

[0133] - used to implement Maximum allowable lateral slip rate

[0134] - Wheel rotation speed request, i.e., target wheel speed to be controlled

[0135] - Residual lateral force capacity of a given wheel

[0136] - Gradient relative to the wheel speed at the requested tire operating point

[0137] - Gradient relative to the wheel speed at the requested tire operating point

[0138] Tire stiffness This can be an estimated tire stiffness that can be corrected for factors such as tire wear, age, temperature, inflation pressure, etc. This can be just the longitudinal slip stiffness that can be used as a basis for proportionally adjusting the lateral slip stiffness of a given tire, or it can be a vector that includes both the longitudinal and lateral slip stiffnesses of the tire. Tire stiffness can have a significant impact on the force of slip ratio curve 400. In the absence of this actual parameter, the nominal stiffness of the tire can be used in the tire model.

[0139] Estimated friction Can be used to adapt the tire force curve 400 to limit the allowed peak forces, and to change the peak force slip location in the model. In the absence of this optional input, the nominal dry asphalt tire force curve can be used.

[0140] Minimum required lateral force capacity and the maximum allowable lateral slip angle limit are optional constraints on the tire model that can be communicated via an interface such as interface 265 between the VMM function 260 and the various MSD control units 230. Using these additional inputs, the resulting longitudinal slip request is constrained in a vector space where the maximum lateral slip angle is used. Guaranteed lateral force capability Both of these optional parameters can be used to request longitudinal forces in a safe manner that does not cause significant yaw instability etc. Can be used to ensure that sufficient lateral force capacity is maintained to enable the vehicle to negotiate a particular bend or perform a task requiring lateral force generation (i.e. ) some other maneuvers, while This can be used to ensure that the yaw moment balance or the sideslip of the vehicle is maintained within reasonable pre-configured or dynamically determined limits. This feature can be particularly beneficial in autonomous or functional safety critical applications where it is desirable to keep the tires within their linear combination slip ratio range (e.g. Figure 3 410 ), thereby preventing any traction control or yaw stability intervention.

[0141] On the output side, is the wheel speed request, and this is the main request from the tire model, given and does not violate and constraints, whenever it is possible to do so, it should lead to the desired It will be appreciated that the speed over the ground can be varied over time. To continuously update the wheel speed request , so that it is equivalent to the wheel slip, such as defined in the wheel slip equation discussed above. Alternatively, the wheel slip value may be transmitted Rather than the wheel speed value. Given the wheel ground speed, wheel slip and wheel speed are equivalent information.

[0142] Residual lateral force capacity , can be used to adjust the boundaries of requests being sent, or as feedback to the control allocator to adapt its control requests to increase , for example, if it is too close to zero.

[0143] at last, and Expresses the longitudinal and lateral forces relative to the wheel rotational speed at the requested operating point These parameters can be used, for example, to customize the gains of the speed controllers in the actuators according to the priorities of the control distributors. For example, if the vehicle is turning and Higher values ​​indicate poor speed control performance which can degrade lateral turning performance, so the speed controller gains can be adapted to prevent this.

[0144] Several variations of the above function interface are of course possible. One possibility is to simply remove the rolling radius input and pass the torque and rotational speed Changed to force and linear velocity respectively, the inverse tire model becomes:

[0145] Another alternative is to simply treat all tire parameters as a single structure argument with a predetermined layout (e.g. Any value in a structure field can be used to update an existing value, while the default value can be used in place of a non-existent field.

[0146] Other options for the output of the inverse tire model could be to send the actual or maximum lateral tire forces Or the currently utilized tire friction capacity in the y direction This will produce a model function according to

[0147] As mentioned above, many of the inputs and outputs of the inverse tire model in the examples above are optional. For example, the parameters The default values ​​of can be used instead of the actual measured values. It should also be understood that the output It is not necessary to control the vehicle at an equivalent wheel speed or wheel slip corresponding to the desired wheel forces.

[0148] You can also add steering angle requests to the inverse tire model , or the target value of the steering angle to be maintained. In this case, the inputs include the required longitudinal wheel forces and lateral wheel forces , and in addition to wheel speed or wheel slip, the output includes the target steering angle for a given wheel ,Right now,

[0149]

[0150] It should also be understood that the wheel rotation speed (ie, given the speed at which the wheel 210 rotates), the wheel slip ratio This is because: at a given wheel ground speed In case of wheel speed request and wheel slip ratio request Via wheel radius In other words, wheel speed and wheel slip are often equivalent amounts of information.

[0151] Summarizing the above discussion, a control unit 130, 140 for controlling a heavy vehicle 100 is disclosed herein. The control unit is arranged to obtain input data indicating desired wheel forces Fx, Fy to be generated by at least one wheel 210 of the vehicle 100 and convert the input data into a corresponding equivalent wheel speed or wheel slip to be maintained by the wheel 210, based on an inverse tire model f of the wheel 210. -1 Desired wheel forces Fx, Fy are generated. Input data indicating the desired wheel forces to be generated can be obtained, for example, from a force distribution process, in which the forces necessary to cause the vehicle to follow a desired acceleration profile and / or a desired curvature are determined. The acceleration profile and curvature can be obtained from manual control input by the driver of vehicle 100 or from an autonomous or semi-autonomous control algorithm running on the VUC. The desired wheel forces can also be obtained, at least in part, from a remote server 190 via a wireless link.

[0152] The data indicative of the desired wheel forces Fx, Fy may include the desired wheel torque Treq and the wheel rolling radius R. By providing the torque and the radius, the equivalent desired wheel force may be determined, for example, as Fx=Treq*R.

[0153] The control units 130, 140 are arranged to obtain an inverse tire model based on the current operating conditions of the wheels 210, and are also arranged to control the heavy vehicle 100 based on the equivalent wheel speed or wheel slip. This means that the control unit is configured to adapt the inverse tire model to the current operating conditions of the vehicle in some way. For example, if the vehicle is loaded with heavy cargo, the inverse tire model used to control the vehicle will be adjusted to take into account the changes in operating conditions. Various types of operating condition parameters can be considered, as discussed below. By obtaining an inverse tire model that depends on the current operating conditions, more accurate control can be achieved, and more robust control can also be achieved. Therefore, it can be understood that the inverse tire model considered here is a dynamic model, which, unlike a constant model, is adapted to suit the current operating conditions of the heavy vehicle. This improves vehicle performance and safety.

[0154] The current operating status may include a x 、v ythe vehicle's or wheel's ground speed vector. This vehicle ground speed can be used to determine the wheel rotational speed corresponding to a given slip, e.g. by calculating the normalized wheel slip difference discussed above. Some tires will also behave differently depending on whether the wheel is rotating slowly or faster. Thus, some inverse tire models can exhibit differences in the operating speed range of 0 km / h to 150 km / h. It can be appreciated that wheel control based on the requested wheel rotational speed requires a relatively fast interface between the VMM function 260 and the MSD control unit 230. This is because the wheel rotational speed required to achieve a given wheel slip rate depends on the ground speed, which can change relatively quickly over time.

[0155] Optionally, the current operating conditions also include a normal load Fz or vertical tire force associated with the wheel 210. The normal load can have a significant impact on the inverse tire model, i.e. the mapping between the desired wheel force and the wheel speed or wheel slip rate. For example, the maximum available longitudinal tire force Fx is limited by the normal force and the friction coefficient. Thus, by parameterizing the inverse tire model based on the normal load Fz, a more accurate inverse tire model can be obtained that more closely models the current operating conditions of the vehicle 100.

[0156] According to some other aspects, the current operating conditions include an estimated tire stiffness Cest of the wheel 210. If the tire stiffness is explicitly estimated, a more accurate inverse tire model can be obtained. For example, the tire stiffness can be estimated based on a feedback system in which the measured values of the tire force are mapped to the wheel slip rate and a linear or semi-linear relationship can be determined. The tire stiffness can also be obtained, for example, from a database maintained in the remote server 190 or a memory connected to the VUC, if the tire can be identified, which can be indexed. Identifying the tire attached to a given wheel can be done, for example, by embedding a radio frequency identification (RFID) device into the tire or by manual configuration.

[0157] The current operating conditions can also include an estimated tire road friction coefficient μ of the wheel. This road friction force can be estimated in real time using known methods, for example the methods disclosed in US 9,475,500 B2, US 8,983,749 B1 or EP 1719676 B1. The inverse tire model can then be adapted to match the current road friction force.

[0158] The current operating condition may also include the minimum required lateral force capability Fy,min and / or the maximum allowable lateral slip α of wheel 210. The minimum lateral force capability Fy,min and the maximum lateral slip angle limit α are optional constraints for the tire model. If these data are used as inputs to an inverse tire model function, these parameters can be used as constraints to determine the output. For example, it can be determined that the output wheel speed or wheel slip ratio will not result in insufficient lateral force capability or lateral slip, which is an advantage.

[0159] In contrast, the inverse tire model f -1 It may also be configured to provide the residual lateral force capacity Fy,rem of the wheel 210. The residual lateral force capacity Fy,rem may be used to adjust the boundaries of the requests being sent, or as feedback to the control distributor to adapt its control requests, thereby increasing the residual lateral force capacity if it becomes too low.

[0160] Inverse tire model f -1 It can also be configured to provide gradients dFx, dFy of the desired wheel force relative to the wheel speed or wheel slip at the tire operating point associated with the desired tire force and the current operating conditions of the wheel 210. These gradients provide information about the model's behavior if the input parameters vary slightly and can be advantageously used to adjust control algorithms, such as in the MSD control unit 230. For example, these gradients can be used to adjust the gains of a control function such as a PID controller.

[0161] Figure 7 is a flow chart illustrating methods that summarize at least some of the above discussion. A method for controlling a heavy vehicle 100 executed in a control unit 130, 140 is shown. The method comprises: obtaining S1 input data indicating desired wheel forces Fx, Fy to be generated by at least one wheel 210 of the vehicle 100; and obtaining S2 an inverse tire model f associated with the wheel 210. -1 , wherein the inverse tire model depends on the current operating condition of the wheel 210. The method further comprises: based on the inverse tire model of the wheel 210, converting S3 the input data into corresponding equivalent wheel speeds or wheel slips to be maintained by the wheel 210 to generate desired wheel forces Fx, Fy; and controlling S4 the heavy vehicle 100 based on the equivalent wheel speeds or wheel slips.

[0162] Figure 8The components of the control unit, such as the VUCs 130, 140, are schematically shown in terms of a number of functional units. The control unit can implement one or more of the above-described functions of the TSM 270, the VMM 260, and / or the MSD control function 230, in accordance with the embodiments discussed herein. The control unit is configured to perform at least some of the functions discussed above for controlling the heavy-duty vehicle 100. The processing circuitry 810 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 820. The processing circuitry 810 can further be provided as at least one application-specific integrated circuit (ASIC), or field programmable gate array (FPGA).

[0163] In particular, the processing circuitry 810 is configured to cause the control unit 101 to perform a set of operations or steps, e.g. in connection with the method discussed above. For example, the storage medium 820 can store the set of operations, and the processing circuitry 810 can be configured to retrieve the set of operations from the storage medium 820 to cause the control unit 900 to perform the set of operations. The set of operations can be provided as a set of executable instructions. Thus, the processing circuitry 810 is arranged to perform methods as disclosed herein. Figure 7

[0164] The storage medium 820 can also include persistent storage, which, as earlier mentioned, can be any type of storage that is not volatile memory. The persistent storage can be a magnetic storage, an optical storage, a solid state storage, or even remotely mounted storage, or a combination thereof.

[0165] The control unit 900 can further include an interface 830 for communication with at least one external device. The interface 830 can include one or more transmitters and receivers, including analog and digital components, and suitable number of ports for wired or wireless communication.

[0166] The processing circuitry 810 controls the general operation of the control unit 900, e.g. by sending data and control signals to the interface 830 and the storage medium 820, by receiving data from the interface 830 and reporting, and by retrieving data and instructions from the storage medium 820. Other components and related functionality of the control node are omitted in order not to obscure the concepts presented here.

[0167] Figure 9 A computer readable medium 910 carrying a computer program is described, the computer program comprising program code means 920 for performing the methods as shown in Figure 7 when the program product is run on a computer. The computer readable medium and the code means can form a computer program product 900 together.

[0168] ​ Figure 10 An exemplary vehicle launch scenario 1000 is shown in which the technology disclosed herein can be advantageously used. The vehicle 100 will experience varying friction conditions 1030, 1040, 1050 as it accelerates 1020. The road 1010 can also be uneven and / or sloped. Since quick control of wheel torque is required when road or vehicle conditions change, torque-based launch control without wheel speed limits will face challenges. For example, the VMM can operate with an update rate of about 10 milliseconds, while the MSD control unit 230 can operate with an update rate of about 1 millisecond (i.e., 10 times faster). This means that the MSD control unit 230 is able to adjust to transient effects faster than VMM-based control, thus overcoming unforeseen resistance during vehicle launch in a better way, while VMM-based control reacts slower to unforeseen changes in driving conditions. On the other hand, the proposed technology simply determines suitable target wheel slip ratio values to be maintained by different MSD controls on each driven wheel and communicates these target wheel slip ratio values (or associated wheel speed limits determined based on the desired wheel slip ratio values) to the MSD control units, which then control the electric machines to maintain the wheel slip ratio at or below the requested values by setting appropriate wheel speeds according to the vehicle speed and the configured target wheel slip ratio or wheel slip ratio limit. This way, the control is moved down in the control stack, closer to the actual electric machines, which improves the overall vehicle launch performance. For example, if Figure 10 the current motor speed at one or more wheels of the vehicle 100 in the system 1000 is above the wheel speed upper limit, the motor controller reduces the applied motor torque. The motor torque continues to be reduced until the motor speed is below or equal to the speed upper limit. Further, if the motor speed is measured to be below the speed lower limit, the torque applied to the electric machine should be increased relative to the last time step. The motor torque should continue to be increased until the motor speed is above or equal to the speed lower limit.

[0169] Figure 11 A method for moving a heavy vehicle 100 is shown, the method comprising: obtaining SB1 a movement instruction for moving the vehicle 100; determining SB2 a target wheel slip ratio limit value λ target and controlling SB3 the wheel speed ω to keep the wheel slip ratio of the vehicle 100 below the target wheel slip ratio limit value λ targetAs discussed herein, the wheel slip rate limits (or equivalently, wheel speed limit values) may be configured as a function of wheel speed. For example, typically the wheel speed limits may be configured as a function of the desired wheel slip rate such that excessive wheel slip does not occur. In this way, a controlled vehicle launch is obtained in an efficient manner since, as opposed to control based solely on torque, control is based directly on wheel speed relative to vehicle speed. Control may be directed more towards one or more propulsion units and away from central vehicle control, which is an advantage since a higher bandwidth control loop (a faster loop) may be achieved in this way. Due to the increased bandwidth of the local control over the bandwidth of the central control, unforeseen drags and transients may be better handled.

[0170] According to the present disclosure, the electric machine WEM is requested to maintain the wheel slip ratio below a target wheel slip ratio limit value λ that has been determined based on a motion command for moving the vehicle (or equivalently, a target wheel speed limit corresponding to the wheel slip ratio limit). target . For example, during a starting operation, the electric motor may simply impose a wheel speed that is close to the configured wheel speed limit. For example, if the target wheel slip limit is set to 0.1, the wheel rotational speed will be continuously set by the WEM at a relative difference of 0.1 above the vehicle speed, so that the wheel will always slip by the configured amount or slightly less. In other words, a target wheel speed difference relative to the vehicle speed is configured and then controlled. This is possible, at least in part, because the electric motor is able to deliver high torque quickly, i.e., it is generally able to produce any wheel slip requested of it (although requesting too much slip is not recommended as this will result in tire burnout). The peak torque capability of an electric motor is generally high, but is only available for a limited time. Therefore, it may be advantageous to draw high peak torque from one or more electric motors during vehicle starting.

[0171] Known methods for controlling a vehicle during launch are based on torque control, meaning torque requests are sent to the electric motors, which then try to fulfill them to the best of their ability within certain slip limits. Compared to known heavy vehicle launch methods, the proposed approach brings control closer to the electric motors.

[0172] According to some aspects, the method includes controlling the SB31 wheel speed ω so that the wheel slip ratio of the corresponding wheel of the vehicle 100 remains below the target wheel slip ratio limit value λ based on the following relationship target :

[0173] in, represents the wheel speed, Indicates the target wheel slip rate limit value, is the reference speed, is the vehicle speed in the wheel reference frame, and denotes the wheel radius.

[0174] According to some aspects, the motion instruction SB11 comprises a requested acceleration a req of the vehicle 100, and the target wheel slip limit λ target is determined SB21 from the longitudinal force Fx’ required to reach the requested acceleration.

[0175] According to some aspects, the method comprises determining SB212 the target wheel slip limit value λ target from a predetermined relationship 400 between the longitudinal force Fx’ required to reach the requested acceleration and the lateral force Fy and the longitudinal wheel slip rate.

[0176] According to some aspects, the method comprises determining SB211 the longitudinal force Fx’ required to reach the requested acceleration from the relationship Fx’ = m * a req , where m is the mass of the vehicle 100, and a req is the requested acceleration of the vehicle 100.

[0177] According to some aspects, the predetermined relationship 400 between the lateral force Fy and the longitudinal wheel slip rate is preconfigured SB213 from the estimated road conditions.

[0178] According to some aspects, the motion instruction SB12 comprises a requested end speed v req of the vehicle 100, and the target wheel slip limit λ target is a preconfigured wheel slip limit value SB22.

[0179] According to some aspects, the method comprises controlling SB311 the wheel speed ω so that the wheel slip rate of the vehicle 100 remains below the target wheel slip limit value λ target .

[0180] wherein is set to the requested end speed v req of the vehicle 100.

[0181] According to some aspects, the method comprises controlling SB32 the wheel speed ω so that the vehicle acceleration remains below a preconfigured maximum acceleration value.

[0182] According to some aspects, the method comprises controlling SB33 the speed ω so that the wheel speed remains below a preconfigured maximum wheel speed value.

[0183] According to some aspects, the method includes: if the vehicle speed Above the configured threshold speed , then control SB34 vehicle speed based on torque request with fixed wheel slip limit .

[0184] According to some aspects, the movement instruction SB13 includes the distance d that the vehicle 100 travels from stop to stop. req The method includes integrating the SB4 wheel speed over time to obtain the following distance d req :

[0185] According to some aspects, the motion command corresponds to a request to apply a peak torque within a limited period of time.

[0186] According to some aspects, the method includes transmitting an SB5 wheel speed request to an electric motor connected to a drive wheel via an open differential arrangement, wherein the method includes controlling the wheel speed ω by the electric motor to maintain a wheel slip ratio of the vehicle 100 below a target wheel slip ratio limit value λ target .

[0187] According to some aspects, the method includes: setting the target wheel slip limit value λ to target Increases from an initial value to a predetermined final value.

[0188] Figure 12 A method for controlling at least one actuator 220, 250 of a vehicle 100 is shown. The actuator 220, 250 is configured to apply torque to at least one wheel 210 of the vehicle 100. The applied torque is determined by a control function associated with a control bandwidth. The method includes: configuring (SC1) the control function to control the applied torque to reduce a difference between a first parameter value associated with a current rotational speed of the wheel 210 and a second parameter value associated with a target rotational speed limit for the wheel 210; obtaining (SC2) data indicative of a current operating condition of the vehicle; and setting (SC3) the control bandwidth of the control function based on the current operating condition of the vehicle 100. The method also includes using the control function to control (SC4) the actuator 220, 250.

[0189] This control function should be interpreted as an operational function configured to apply torque to at least one actuator. By controlling the bandwidth, torque can be applied with various response times depending on the current operating conditions. According to one example, a reduced bandwidth can be associated with an increased torque response time for the actuator. Thus, as the bandwidth increases, torque is applied more quickly. Furthermore, the values ​​associated with the current rotational speed of the wheel and the target rotational speed of the wheel should be interpreted as values ​​that can be related to both the rotational wheel speed and the amount of wheel slip (i.e., the difference between the wheel's ground speed and the actual wheel speed). In the latter case, the first parameter can be the current wheel slip of the wheel, while the second parameter can be the target wheel slip of the wheel. One advantage is that the bandwidth is controlled based on the current operating conditions, resulting in a fast torque response when needed and a slower, gentler torque response under other conditions. Consequently, since fast, energy-intensive operations are only performed when needed, comfort during operation is improved, and the vehicle's overall energy consumption can be reduced. Furthermore, the increased configurability allows for additional degrees of freedom when optimizing vehicle control overall. Furthermore, the control function obtains parameters related to the wheel rotational speed. A common approach to requesting a certain tire force from the wheels is to use torque control at the actuator level, based on torque requests sent from higher-level control functions. However, the latency involved in communication between different control functions (e.g., via the Controller Area Network (CAN) bus) significantly limits slip control performance. Therefore, speed-based control functions are employed, which compare favorably to, for example, torque-based control. Specifically, for the electric motor, locally executed speed-based wheel slip control is faster than centrally managed torque control, primarily due to CAN message cycle times.

[0190] As described in further detail below, this method can preferably be performed using a vehicle motion management system and an actuator control system. When such a vehicle motion management system and actuator control system are implemented, the bandwidth can be controlled in a variety of different ways. For example, the vehicle motion management system can be configured to transmit a control signal to the actuator control system, the signal including data related to a target bandwidth and vehicle operating conditions. Thus, the target bandwidth is set / determined by the vehicle motion management system. Based on the target bandwidth, the actuator control system determines a control bandwidth based on various parameters to achieve the target bandwidth.

[0191] The first parameter value mentioned above may be, for example, the rotational speed of the wheel or the current wheel slip ratio of the wheel. Therefore, the second parameter value may be the target rotational speed of the wheel or the target wheel slip ratio of the wheel.

[0192] Figure 13A method for controlling at least one actuator 220, 250 to apply torque to at least one wheel 210 of a vehicle 100, performed in an actuator control system, is shown. The actuator control system includes a control function, and the applied torque is determined by the control function in association with a control bandwidth. The method includes determining a first parameter value (SC10) associated with a current rotational speed of the wheel 210; configuring the control function (SC20) to control the applied torque to reduce a difference between the first parameter value and a second parameter value associated with a target rotational speed of the wheel 210; and obtaining data (SC30) indicative of a current operating condition of the vehicle. The method also includes setting a control bandwidth (SC40) of the control function based on the current operating condition of the vehicle, and controlling the actuator (SC50) using the control function.

[0193] According to some aspects, the control function is configured to control the speed of the actuators 220 , 250 .

[0194] According to some aspects, the increased bandwidth of the control function is associated with an increased torque response of the actuator.

[0195] According to some aspects, a control bandwidth of the control function is controlled using a predetermined set of feedback gains for the actuators, each feedback gain being associated with a specific operating condition of the vehicle.

[0196] According to some aspects, the control function is a PID controller.

[0197] According to some aspects, the control function is a proportional controller, the method further comprising obtaining a signal indicative of a target bandwidth for the control function and configuring the control function using the target bandwidth and a proportional parameter related to current operating conditions of the vehicle.

[0198] Figure 14 A method is shown, executed in a vehicle motion management system 260 of a vehicle 100, which is connectable to an actuator control system for transmitting control signals between the vehicle motion management system and the actuator control system. The method includes obtaining (SC100) a current speed of the vehicle 100; determining (SC200) a current operating condition of the vehicle 100; and transmitting (SC300) a control signal to the actuator control system. This control signal represents an instruction that, when executed by the actuator control system, causes a control function of the actuator control system to apply a torque to at least one wheel of the vehicle in association with a control bandwidth to reduce a difference between a first parameter value related to a current rotational speed of the wheel based on the current speed of the vehicle and a second parameter value related to a target rotational speed of the wheel. The control bandwidth may be determined based on the current operating condition of the vehicle.

[0199] According to some aspects, the method further includes determining a target speed for the vehicle based on current operating conditions, wherein the target rotational speed of the wheel is based on the target speed for the vehicle.

[0200] According to some aspects, the method further includes determining a desired operating performance of the vehicle based on current operating conditions, wherein the control bandwidth may also be determined based on the desired operating performance of the vehicle.

[0201] According to some aspects, the method further includes determining a target bandwidth and transmitting a control signal including the determined target bandwidth, wherein the control bandwidth may be further determined based on the target bandwidth.

[0202] According to some aspects, the current operating condition of the vehicle is based on at least one of a current vehicle condition and a current road condition on which the vehicle is operating.

[0203] According to some aspects, the current operating condition is at least one of a current vehicle mass, a road inclination at which the vehicle is traveling, a vehicle speed, a level of friction between vehicle wheels and a road surface, and a current tire stiffness.

[0204] Also disclosed herein is an actuator control system for a vehicle 100, the actuator control system being configured to control at least actuators 220, 250 to apply torque to at least one wheel of the vehicle. The actuator control system includes a control function, and the applied torque is determined by the control function in association with a control bandwidth. The actuator control system is configured to determine a first parameter value associated with a current rotational speed of the wheel, configure the control function to control the applied torque to reduce a difference between the first parameter value and a second parameter value associated with a target rotational speed of the wheel, obtain data indicative of a current operating condition of the vehicle, set a control bandwidth of the control function based on the current operating condition of the vehicle, and control the actuator using the control function.

[0205] Also disclosed herein is a vehicle motion management system 260 for the vehicle 100, the vehicle motion management system 260 being connectable to an actuator control system for transmitting control signals between the vehicle motion management system and the actuator control system, wherein the vehicle motion management system is configured to obtain a current speed of the vehicle, determine a current operating condition of the vehicle, and transmit a control signal to the actuator control system. The control signal represents an instruction that, when executed by the actuator control system, causes a control function of the actuator control system to apply a torque to at least one wheel of the vehicle in association with a control bandwidth determined based on the current operating condition of the vehicle to reduce a difference between a first parameter value associated with a current rotational speed of the wheel and a second parameter value associated with a target rotational speed of the wheel.

[0206] Furthermore, disclosed herein are control signals representing instructions to be executed by an actuator control system of vehicle 100. The control signals include a vehicle speed component that enables the actuator control system to determine the current rotational speed of wheel 210 and a vehicle operating condition component representing instructions. When executed by the actuator control system, these instructions cause a control function of the actuator control system to apply torque to at least one wheel of the vehicle in association with a control bandwidth, which may be determined based on the current vehicle operating condition, to reduce a difference between a first parameter value associated with the current rotational speed of the wheel and a second parameter value associated with a target rotational speed of the wheel.

[0207] Reference Figure 8 、 Figure 15 and Figure 16, shows a control unit 130, 140 for controlling a vehicle wheel 210 provided with a tire 1502. The control unit includes or is operatively connected to a data storage device 820 having a stored tire model 400, 1504 for the tire, wherein in the tire model, the longitudinal tire force Fx is represented as at least a function of a longitudinal wheel slip λ, which depends on the rotational speed of the wheel and the speed of the vehicle. The control unit is configured to receive at least one tire parameter input, including a measured value of at least one parameter affecting the longitudinal slip stiffness of the tire, and to correct the function in the stored tire model based on the received tire parameter input. The control unit is further arranged to obtain or generate a wheel torque request, convert the obtained or generated wheel torque request into a wheel rotational speed limit request based on the corrected function, and send the wheel rotational speed limit request to an actuator to provide a wheel rotational speed below the wheel rotational speed limit request. This concept is based on the recognition that by providing torque control in the same vehicle subsystem as slip control, latency issues can be avoided. Compared to a vehicle control unit that conventionally sends torque requests, such a subsystem has a relatively fast response time. More specifically, it has been recognized that by using a tire model in which the longitudinal tire force is at least a function of the longitudinal wheel slip, a slip control subsystem can be used to provide a slip request corresponding to the desired longitudinal force. In particular, it has been recognized that, in addition to providing the advantage of a fast response time, in order for such control to be accurate, the tire model should be capable of being corrected based on one or more parameters that affect the tire slip stiffness. Thus, in general, by adapting the force / slip-based tire model to the current state of the tire or the current driving conditions, accurate and fast control of the wheels can be achieved. Wheel slip limits and / or wheel speed limits can be determined and configured in a similar manner.

[0208] As previously explained, in order to provide accurate control of the wheel 210 based on the tire model 400, the tire model should be updated to the current conditions. Here, wheel control should be broadly interpreted to include control actions such as torque control, in which the applied torque is controlled to follow a target torque, speed control, or wheel slip control, in which the wheel rotational speed is controlled to follow a target speed, or wheel slip control, in which the wheel speed or torque is controlled to follow a target wheel slip ratio as closely as possible.

[0209] Tires can be affected by a variety of factors, such as ambient temperature, inflation pressure, normal load, age, wear, etc. These and other factors can be appropriately quantified as measurable parameters and provided as tire parameter inputs. Figure 3When VMM 260 obtains a wheel torque request or otherwise determines a desired tire force to be generated at wheel 210, it can convert the obtained wheel torque request or desired tire force into a wheel rotational speed request or wheel slip ratio request based on a correction function of the tire model. Equivalently, it can determine a wheel speed limit and / or a wheel slip ratio limit and send it as a request to MSD control unit 230.

[0210] According to some aspects, tire 1502 forms part of a kit 1500 that also includes a tire model 1504. Figure 15 However, tire model signal 1504 may be stored on a variety of conceivable media and need not be physically delivered with tire 1502, but may be accessed by downloading tire model 1504 from a remote server or the like.

[0211] The at least one parameter is optionally selected from the group consisting of: - Age of the tire t act , -Ambient temperature T act - Tire inflation pressure P act , - normal load on the tire, and - the wear of the tire, appropriately approximated as the distance d traveled by the tire act .

[0212] According to some aspects, the control unit is configured to apply a slip stiffness correction factor c to the function p 、c T 、c a 、c w To correct the function in the stored tire model 400, the slip stiffness correction factor has a variation with respect to the parameter.

[0213] According to some aspects, the control unit is configured to receive a plurality of different tire parameter inputs, each tire parameter input comprising a measured value of a respective one of a plurality of parameters affecting the longitudinal slip stiffness of the tire. The control unit is further configured to correct the function in the stored tire model 400 by applying a combined correction factor to the function, the combined correction factor being a function of a plurality of slip stiffness correction factors, wherein each slip stiffness correction factor has a variation relative to a respective one of the plurality of parameters.

[0214] According to some aspects, the at least one tire parameter input is a primary tire parameter input, and the at least one parameter is a primary parameter, wherein the control unit is further configured to calibrate the function in the stored tire model 400 based on at least one secondary tire parameter input, the secondary tire parameter input comprising a measured value of at least one secondary parameter selected from the group consisting of: - rolling radius, - nominal peak friction, and - Rolling resistance coefficient.

[0215] According to some aspects, the control units 130, 140 are configured to calculate a slip ratio request based on the corrected function when converting the wheel torque request to the wheel rotational speed request, and convert the slip ratio request to the wheel rotational speed request using the following slip ratio formula:

[0216] where λ is the longitudinal wheel slip, where Rω is the rotational speed of the wheel, where R is the wheel radius in meters, ω is the angular velocity of the wheel, and where v x is the longitudinal velocity of the wheel.

[0217] Figure 16 A method for controlling torque applied to a wheel of a vehicle provided with a tire is shown, comprising: receiving SD1 at least one tire parameter input, the tire parameter input comprising a measured value of at least one parameter influencing the longitudinal slip stiffness of the tire; and correcting SD2 a tire model based on the received tire parameter input, wherein in the tire model, longitudinal tire force is represented as a function of longitudinal wheel slip, the longitudinal wheel slip being dependent on the rotational speed of the wheel and the speed of the vehicle, wherein the step of correcting the tire model comprises correcting the function. The method further comprises:

[0218] A wheel torque request is obtained or generated SD3 , converted SD4 into a wheel rotational speed request based on a corrected function, and the wheel rotational speed request is sent SD5 to an actuator to provide a wheel rotational speed corresponding to the wheel rotational speed request.

[0219] According to some aspects, the at least one parameter is selected from the group consisting of: - the age of the tires, - ambient temperature, - the inflation pressure of the tire, - normal load on the tire, and - The wear of the tire, appropriately approximated by the distance the tire has traveled.

[0220] According to some aspects, the act of correcting SD2 includes applying a slip stiffness correction factor to the function, the slip stiffness correction factor having a variation with respect to the parameter.

[0221] According to some aspects, the method further includes receiving a plurality of different tire parameter inputs, each tire parameter input including a measured value of a corresponding one of a plurality of parameters affecting tire longitudinal slip stiffness, wherein the correcting step includes applying a combined correction factor to the function, the combined correction factor being a function of a plurality of slip stiffness correction factors, wherein each slip stiffness correction factor has a variation relative to a corresponding one of the plurality of parameters.

[0222] According to some aspects, the at least one tire parameter input is a primary tire parameter input and the at least one parameter is a primary parameter, wherein the act of correcting SD2 comprises correcting the function in the stored tire model based on at least one secondary tire parameter input, the secondary tire parameter input comprising a measured value of at least one secondary parameter, the at least one secondary parameter selected from the group consisting of: - rolling radius, - nominal peak friction, and - Rolling resistance coefficient.

[0223] According to some aspects, the act of converting SD4 includes calculating a slip ratio limit request based on the corrected function and converting the slip ratio limit request into a wheel rotational speed limit request using a slip ratio formula:

[0224] where λ is the longitudinal wheel slip, Rω is the rotational speed of the wheel, and is the wheel radius in meters, ω is the angular velocity of the wheel, and where V x is the longitudinal velocity of the wheel.

[0225] Reference Figure 2According to a non-limiting example, vehicle motion management system 260 includes a torque module 202, a wheel slip module 204, and a friction module 206. Vehicle motion management system 260 is also configured to receive a vehicle operating signal s, which includes data that can be acted upon by vehicle motion management system 260 and its various modules 202, 204, 206. Vehicle operating signal s provided to vehicle motion management system 260 may, for example, include data in the form of signals indicating the vehicle's current environment, current traffic conditions, and vehicle weight parameters (e.g., whether the vehicle is fully loaded, unloaded, partially loaded, etc.). Vehicle motion management system 260 may also receive other signals indicating specific vehicle conditions, such as current vehicle operating conditions, as will be discussed below. The torque module 202, wheel slip module 204, and friction module 206 are configured to transmit communication signals between each other; i.e., the different modules are configured to communicate with each other, as will be apparent from the following disclosure. It should be readily understood that the torque module 202, wheel slip module 204, and friction module 206 are shown as separate components for illustrative purposes only. Of course, the vehicle motion management system 260 may also simply include the various control functions themselves that perform the functions described below.

[0226] According to another example, vehicle motion management includes normal driver control inputs (ie, manual steering inputs) as well as acceleration and braking inputs indicative of desired torque.

[0227] Therefore, a vehicle kinematics management system for a vehicle is provided, the vehicle kinematics management system being connectable to a kinematics support system for communicating control signals between the vehicle kinematics management system and the kinematics support system. The vehicle kinematics management system is configured to determine a desired torque for operating the vehicle under current vehicle operating conditions; determine a wheel slip limit for at least one wheel of the vehicle; determine a wheel speed limit for the at least one wheel of the vehicle based at least on the wheel slip limit; and transmit a control signal indicative of the desired torque and wheel speed limit to the kinematics support system. The vehicle kinematics management system and the kinematics support system are control systems of the vehicle, wherein each of these control systems is configured to perform various control functions for controlling the operation of the vehicle, particularly the operation of the wheels. The vehicle kinematics management system is preferably configured to receive and determine wheel parameters at a higher level, i.e., the vehicle kinematics management system determines the desired torque and wheel slip limit in a more generalized form, while the kinematics support system is configured as a lower-level control system configured to convert the parameters received from the vehicle kinematics management system into appropriate parameters for actuators. The kinematics support system considers the current driveline state(s) before forwarding the actuator signals to the actuators. For example, the current driveline state may relate to the current vehicle transmission state, the gear position of the vehicle transmission, or the transmission clutch actuation state. For example, the desired torque may be received from the vehicle operator depressing the accelerator pedal and / or the brake pedal. The desired torque may also be received from a system that autonomously controls vehicle propulsion operations or from an advanced driver assistance system (ADAS). The wheel slip limit should be interpreted as the maximum allowable wheel slip of the at least one wheel during operation. Wheel slip is the relative longitudinal motion, i.e., the amount of "slip," between a vehicle wheel and the ground on which it rests. Taking into account the wheel radius, wheel slip can be determined as the relationship between the longitudinal wheel speed and the rotational wheel speed. Therefore, the wheel speed limit is based on the wheel speed relative to the road surface, as viewed in a wheel-based coordinate system. According to an example embodiment, the vehicle motion management system may be configured to determine a current rotational wheel speed and a current longitudinal wheel speed of at least one wheel of the vehicle; and to determine the wheel slip of the at least one wheel based on the current rotational wheel speed and the current longitudinal wheel speed. As discussed above, the configured wheel slip limits are in many respects equivalent to configured wheel speed limits, where the wheel speed limits are determined in real time based on the vehicle's ground speed.

[0228] The present disclosure is based on the recognition that, by transmitting a control signal indicative of the desired torque to the motion support system in combination with a wheel speed limit, the calculation of the wheel slip limit can be performed by a higher-level vehicle motion management system. When calculating wheel slip, the denominator in the wheel slip equation consists of the wheel rotational speed of the wheel. Consequently, at low vehicle speeds, this denominator is close to zero or approaches zero, which can lead to a source of error when calculating wheel slip. Performing wheel slip calculation in a higher-level vehicle motion management system is therefore advantageous because potential inconsistencies when calculating wheel slip by a separate motion support system can be avoided. Improved wheel slip consistency is thereby achieved.

[0229] Furthermore, when operating the vehicle using electric motors, transmitting control signals to the motion support system indicating desired torque and wheel speed limits is particularly advantageous, as the electric motors can be speed- and torque-controlled. Speed ​​control, as opposed to slip control, is also easier to implement for, for example, the service brakes, as rotational speed is a common output of the tire torque balancing system and does not include any nonlinearities present in the wheel slip equations.

[0230] According to an example embodiment, the wheel speed limits may be further based on the desired torque. Thus, the desired torque (ie, the torque request) is used to calculate the slip ratio limits, which are used when calculating the wheel speed limits.

[0231] According to an example embodiment, the wheel speed limit may include an upper wheel speed limit and a lower wheel speed limit. The vehicle motion management system may be further configured to transmit the upper wheel speed limit to the

[0232] The functional operation of vehicle motion management system 260 will now be described. Specifically, vehicle motion management system 260 is configured to receive input signals having information related to the current vehicle operating conditions. For example, the current vehicle operating conditions may include data indicating the level of wheel friction between the vehicle's wheels and the road surface, or the vehicle's current weight, i.e., whether the vehicle is unladen, fully laden, or partially laden, or the topology of the road on which the vehicle is currently operating. Thus, various operating conditions may be received by vehicle motion management system 260 as separate components, or as a component that uses all of the different operating conditions as an overall vehicle operating condition. Suitable sensors may be used to determine the different operating conditions of the vehicle and transmit them to vehicle motion management system 260.

[0233] As described above, vehicle motion management system 260 also includes friction module 206. According to an example embodiment, vehicle motion management system 260 is arranged to determine a wheel friction level between at least one wheel and the road surface using friction module 206. Vehicle motion management system 260 may determine a current vehicle operating condition based on the determined wheel friction level.

[0234] The torque module 202 is adapted to determine the desired torque for operating the vehicle under current vehicle operating conditions. Accordingly, the vehicle motion management system 260 determines the torque request in the aforementioned higher level vehicle motion management system 260 to appropriately control the vehicle 100 under current operating conditions.

[0235] For example, the desired torque may be determined based on a current accelerator pedal position, brake pedal position, or based on signals received from an autonomous vehicle operating system.

[0236] The wheel slip module 204 is arranged to determine a wheel slip limit for at least one wheel 210 of the vehicle 100. Thus, a maximum allowable wheel slip for the vehicle is determined, wherein a wheel of the vehicle is not allowed to exceed such wheel slip limit.

[0237] The wheel slip limit can be achieved by combining Figure 4 The vehicle motion management system 260 can thereby convert the force request into a slip rate request, thereby setting the slip rate limit based on the slip rate request. According to another example, the slip rate limit can be set to a fixed value independent of the force request. The slip rate limit can also be based on a signal indicating the current level of friction between the road surface and the tire surface.

[0238] Based on the wheel slip ratio limit, the wheel slip ratio module 204 is configured to determine a wheel speed limit for at least one wheel. Thus, the vehicle motion management system 260 performs a wheel slip ratio limit calculation and a wheel speed limit calculation. According to a non-limiting example, the wheel speed limit ω w, sl It can be determined according to the following equation:

[0239] in:

[0240] λ lim is the wheel slip limit; and

[0241] T Reg is the desired torque.

[0242] Where wheel speeds are relatively low (ie, close to zero), the vehicle motion management system 260 may be arranged to determine wheel slip based on an offset wheel speed parameter, from which an offset wheel speed limit may be calculated according to the following non-limiting equation:

[0243] in:

[0244] ω w,ol is the wheel speed limit calculated based on the speed offset limit;

[0245] k ol,ω and ω ol,max are the gain and maximum speed offset parameters used to convert the slip rate limit into an offset limit; and

[0246] sgn(λ) is a sign function that is equal to 1 during acceleration and equal to −1 during deceleration.

[0247] Furthermore, the wheel speed limits may include an upper wheel speed limit and a lower wheel speed limit, wherein the upper wheel speed limit is used during acceleration, i.e., during propulsion, and the lower wheel speed limit is used during deceleration, i.e., during braking. The upper wheel speed limit is used when the wheel slip limit is positive and the desired torque is greater than zero (i.e., during acceleration), while the lower wheel speed limit is used when the wheel slip limit is negative and the desired torque is less than zero (i.e., during deceleration). Furthermore, the wheel slip limit is within a predetermined range, defined as: -1 < λ lim < 1

[0248] exist Figure 4 The wheel slip characteristics with respect to the longitudinal and lateral tire forces are depicted in . Therefore, Figure 4 A model 400 is shown that represents the relationship between the calculated longitudinal wheel slip and the estimated longitudinal wheel force values. The model can also represent the relationship between the maximum available lateral wheel forces for a given longitudinal wheel slip. For a predetermined lateral slip angle of the tire, the model can also represent the lateral wheel forces achieved for a given longitudinal wheel slip. The vertical axis represents the tire force generated between the surface supporting the wheel and the wheel 210 itself, while the horizontal axis represents the longitudinal wheel slip of the wheel.

[0249] Reference again Figure 2 When the wheel speed limits and the desired torque have been determined, the vehicle motion management system 260 transmits a control signal to the motion support system or MSD control unit 230 via the interface 265 , wherein the control signal indicates the desired torque and wheel speed limits.

[0250] The motion support system 230 may include an actuator torque module. The actuator torque module is configured to determine actuator-specific torque, that is, to convert desired torque data from the vehicle motion management system 260 into actuator-specific data. Specifically, the actuator torque module determines the operating torque based on the desired torque received from the vehicle motion management system 260 and based on the current powertrain state of the vehicle 100.

[0251] The actuator torque module also determines the actuator rotational speed limits for the actuators 220 and 250. The actuator rotational speed limits are based on the wheel speed limits received from the vehicle motion management system 260. The actuator rotational speed limits can also be based on the current powertrain state. Thus, the motion support system 230 has converted the wheel speed limits received from the vehicle motion management system 260 into wheel-specific rotational wheel speed limits.

[0252] Thereafter, the motion support system 230 transmits actuator control signals 590 to the actuators 220 , 250 to generate operating torque on the wheel 210 without exceeding the actuator rotational speed limit.

[0253] In summary, this document discloses a vehicle motion management system 260 for a vehicle, which is capable of being connected to a motion support system 230 for transmitting control signals between the vehicle motion management system 260 and the motion support system 230, wherein the vehicle motion management system is configured to determine the desired torque for operating the vehicle under current vehicle operating conditions, determine a wheel slip limit of at least one wheel of the vehicle, determine a wheel speed limit of the at least one wheel of the vehicle based at least on the wheel slip limit; and transmit a control signal indicating the desired torque and wheel speed limit to the motion support system 230.

[0254] According to some aspects, the wheel speed limit is further based on a desired torque.

[0255] According to some aspects, upper and lower wheel speed limits or wheel slip limits are determined and transmitted to the motion support system 230 .

[0256] According to some aspects, the wheel speed limits include an upper wheel speed limit and a lower wheel speed limit, and the vehicle motion management system is configured to transmit the upper wheel speed limit to the motion support system 230 at least when the desired torque is above zero, and to transmit the lower wheel speed limit to the motion support system 230 at least when the desired torque is below zero.

[0257] According to some aspects, vehicle motion management system 260 is further configured to determine an offset wheel speed parameter, obtain a signal indicative of vehicle wheel speed, and determine a wheel slip limit based on the offset wheel speed parameter when the wheel speed is below a threshold vehicle speed limit.

[0258] According to some aspects, the vehicle motion management system 260 is further configured to determine a current rotational wheel speed and a current longitudinal wheel speed of at least one of the vehicle's wheels, and determine a wheel slip ratio of the at least one wheel based on the current rotational wheel speed and the current longitudinal wheel speed.

[0259] According to some aspects, the wheel slip rate limit is within a predetermined wheel slip rate range.

[0260] According to some aspects, the vehicle motion management system 260 is further configured to obtain a signal indicative of a current accelerator pedal position of an accelerator pedal of the vehicle and determine the desired torque based on the current accelerator pedal position.

[0261] According to some aspects, the desired torque is determined based on signals received from an autonomous vehicle operating system.

[0262] According to some aspects, vehicle motion management system 260 is further configured to determine a wheel friction level between at least one wheel and a road surface, and determine a current vehicle operating condition based on the determined wheel friction level.

[0263] Also disclosed herein is a motion support system 230 for a vehicle, the motion support system 230 being connectable to a vehicle motion management system 260 and at least one actuator configured to apply torque to at least one wheel of the vehicle. The motion support system 230 is configured to receive a control signal from the vehicle motion management system 260 indicating a desired torque for operating the vehicle under current vehicle operating conditions and indicating a wheel speed limit for the at least one wheel of the vehicle, determine a current vehicle powertrain state of the vehicle, determine an operating torque and an actuator rotational speed limit based on the current vehicle powertrain state, the desired torque, and the wheel speed limit, and transmit an actuator signal to the actuator to cause the actuator to generate the operating torque at the at least one wheel without exceeding the actuator rotational speed limit.

[0264] According to some aspects, the current vehicle powertrain state is one of a current vehicle transmission state, a gear of a vehicle transmission, or a transmission clutch actuation state.

[0265] According to some aspects, wheel motion system 230 is a decentralized wheel motion system 230 connectable to wheel-specific actuators configured to control a single wheel of the vehicle.

[0266] Figure 17 A method for controlling an actuator of a vehicle is described, the actuator being configured to apply a torque to at least one wheel 210 of the vehicle, wherein the method comprises determining SE1 a desired torque for operating the vehicle under current vehicle operating conditions, determining SE2 a wheel slip limit for the at least one wheel of the vehicle, determining SE3 a wheel speed limit for the at least one wheel of the vehicle based at least on the wheel slip limit, determining SE4 an operating torque and an actuator rotational speed limit based on the desired torque, the wheel speed limit, and a current vehicle driveline state, and controlling SE5 the actuator to produce the operating torque on the at least one wheel without exceeding the actuator rotational speed limit.

[0267] Note that the torque request may come from the propulsion management system (which may not account for lateral motion, etc.). Intuitively, wheel speed limits or wheel slip limits can be directly converted to motor speed limits. Therefore, such limits are considered equivalent in this article. Furthermore, as discussed herein, at lower speeds, a "speed offset" can be used instead of wheel slip.

[0268] Disclosed herein is a control signal representing an instruction to be executed by a motion support system 230, the control signal including a torque component enabling the motion support system 230 to determine an operating torque and a wheel speed limit component representing wheel speed limit data. When executed by the motion support system 230, the wheel speed limit data causes the motion support system 230 to generate an actuator signal corresponding to the operating torque subject to an actuator rotational speed limit, the actuator rotational speed limit being determinable based on the wheel speed limit component in consideration of a current vehicle powertrain state.

[0269] Also disclosed herein is a motion support device MSD control unit 230 for a heavy vehicle 100, the control unit 230 being configured to control one or more MSDs 220, 250 associated with at least one wheel 210 on the vehicle 100.

[0270] The MSD control unit 230 is arranged to be communicatively coupled 265 to a vehicle motion management VMM unit 260 for receiving control commands including wheel speed limit and / or wheel slip limit requests from the VMM unit 260 to control vehicle motion via the one or more MSDs 220, 250.

[0271] wherein the MSD control unit 230 is arranged to obtain a capability range indicating a range of wheel behavior of the wheel 210 for which the VMM unit 260 is allowed to influence the behavior of the wheel by means of the control command, and

[0272] The MSD control unit 230 is arranged to monitor the wheel behavior and detect whether the wheel behavior is outside the capability range.

[0273] Therein, the MSD control unit 230 is arranged to trigger a control intervention function if the monitored wheel behavior is outside the capability range.

[0274] According to some aspects, the one or more MSDs include at least one service brake 220 arranged to generate negative torque through the wheels 210 .

[0275] According to some aspects, the one or more MSDs include at least one propulsion unit 250 arranged to generate positive torque and / or negative torque via the wheels 210 .

[0276] According to some aspects, the capability range includes upper limits on permissible positive and / or negative longitudinal wheel slip and / or wheel rotational speed.

[0277] According to some aspects, the capability range includes upper limits on permissible positive and / or negative longitudinal wheel accelerations.

[0278] According to some aspects, the capability range includes an upper limit on permissible positive and / or negative vehicle yaw rates.

[0279] According to some aspects, the capability range includes lower limits on permissible positive and / or negative longitudinal wheel slip and / or wheel rotational speed.

[0280] According to some aspects, the capability range includes a lower limit on permissible positive and / or negative longitudinal wheel acceleration.

[0281] According to some aspects, the capability range includes a lower limit on permissible positive and / or negative vehicle yaw rates.

[0282] According to some aspects, the MSD control unit 230 is arranged to receive wheel speed data associated with the wheel 210 from the wheel speed sensor 240 and detect whether the wheel behavior is outside the capability range based on the wheel speed data.

[0283] According to some aspects, the MSD control unit 230 is arranged to obtain the fixed capability range as a parameter loaded from memory or received from an external configuration entity.

[0284] According to some aspects, the MSD control unit 230 is arranged to continuously obtain updated capability ranges.

[0285] According to some aspects, controlling the intervention function includes executing the intervention function by one or more of the MSDs 220 , 250 .

[0286] According to some aspects, the control intervention function includes triggering a request for an external arbitrator function to directly perform MSD control by the MSD control unit 230 .

[0287] According to some aspects, the MSD control unit 230 is arranged to monitor the wheel behavior by filtering samples of the wheel behavior over time, and detect whether the wheel behavior is outside the capability range based on a result of the filtering.

[0288] Also disclosed herein is a vehicle motion management VMM unit 260 arranged to perform vehicle motion management for controlling the motion of a heavy vehicle 100 via one or more motion support devices MSD 220, 250 associated with at least one wheel 210 on said vehicle 100.

[0289] The VMM unit 260 is arranged to be communicatively coupled 265 to the MSD control unit 230 for transmitting control commands including wheel speed and / or wheel slip ratio requests to the MSD control unit 230 to control vehicle motion via the one or more MSDs 220, 250.

[0290] wherein the VMM unit 260 is arranged to obtain a capability range indicating a range of wheel behavior of the wheel 210 for which the VMM unit 260 is allowed to influence the behavior of the wheel by means of the control command, and

[0291] The VMM unit 260 is arranged to generate the control command so that the wheel behavior is within the capability range.

[0292] According to some aspects, the VMM unit 260 includes an arbiter function configured to receive a request for direct MSD control by the MSD control unit 230 and yield vehicle control to the MSD control unit 230 if the wheel behavior is within a predetermined wheel behavior safety range.

[0293] Figure 18 A method for controlling movement by a heavy vehicle 100 is shown, the method comprising:

[0294] configuring an SF1 motion support device MSD control unit 230 to control one or more MSDs 220, 250 associated with at least one wheel 210 on said vehicle 100,

[0295] configuring the SF2 vehicle motion management VMM unit 260 to perform vehicle motion management by the one or more MSDs 220 , 250 via control commands transmitted to the MSD control unit 230 ,

[0296] defining an SF3 capability range, the capability range indicating a wheel behavior range of the wheel 210 , for which the VMM unit 260 is allowed to influence the wheel behavior through the control command,

[0297] Monitoring SF4 wheel behavior, and

[0298] In the event that the monitored wheel behavior is outside a defined capability range, the MSD control unit 230 triggers the SF5 control intervention function.

[0299] Example

[0300] Example 1. A vehicle motion management system (260) for a vehicle, the vehicle motion management system being connectable to a motion support system (230) for transmitting control signals between the vehicle motion management system and the motion support system, wherein the vehicle motion management system is configured to: - determining a desired torque for operating the vehicle under current vehicle operating conditions; - determining a wheel slip limit for at least one wheel of the vehicle; - determining a wheel speed limit for said at least one wheel of said vehicle based at least on said wheel slip limit; and - transmitting a control signal indicative of the desired torque and the wheel speed limit to the motion support system (230).

[0301] Example 2. The vehicle motion management system (260) of example 1, wherein the wheel speed limit is further based on a desired torque and / or a current wheel speed.

[0302] Example 3. The vehicle motion management system (260) of Example 2, wherein the wheel speed limit comprises an upper wheel speed limit and a lower wheel speed limit, and the vehicle motion management system is configured to: - transmitting the upper wheel speed limit to the motion support system (230) at least when the desired torque is above zero; and - transmitting the wheel speed lower limit to the motion support system (230) at least when the desired torque is below zero.

[0303] Example 4. The vehicle motion management system (260) of any one of the preceding examples, wherein the motion management system (260) is further configured to: - Determine offset wheel speed parameters; - obtaining a signal indicative of a wheel speed of said vehicle; and - determining the wheel slip limit based on the offset wheel speed parameter when the wheel speed is below a threshold vehicle speed limit.

[0304] Example 5. The vehicle movement management system (260) according to any one of the preceding examples, wherein the vehicle movement management system (260) is further configured to: - determining a current rotational wheel speed and a current longitudinal wheel speed of at least one of said wheels of said vehicle; and - determining a wheel slip of the at least one wheel based on the current rotational wheel speed and the current longitudinal wheel speed.

[0305] Example 6. The vehicle motion management system (260) of any one of the preceding examples, wherein the wheel slip rate limit is within a predetermined wheel slip rate range.

[0306] Example 7. The vehicle movement management system (260) of any one of the preceding examples, wherein the vehicle movement management system (260) is further configured to: - obtaining a signal indicative of a current accelerator pedal position of an accelerator pedal of said vehicle; and - determining a desired torque based on the current accelerator pedal position.

[0307] Example 8. The vehicle motion management system (260) of any of Examples 1-6, wherein the desired torque is determined based on a signal received from an autonomous vehicle operating system.

[0308] Example 9. The vehicle movement management system (260) of any one of the preceding examples, wherein the vehicle movement management system (260) is further configured to: - determining a level of wheel friction between said at least one wheel and a road surface; and - determining said current vehicle operating condition based on the determined wheel friction level.

[0309] Example 10. A motion support system (230) for a vehicle, the motion support system (230) being connectable to a vehicle motion management system (260) and to at least one actuator configured to apply torque to at least one wheel of the vehicle, wherein the motion support system (230) is configured to: - receiving a control signal from the vehicle motion management system (260), the control signal indicating a desired torque for operating the vehicle under current vehicle operating conditions and indicating a wheel speed limit for the at least one wheel of the vehicle; - determining a current vehicle powertrain state of said vehicle; - determining operating torque and actuator rotational speed limits based on the current vehicle powertrain state, the desired torque and the wheel speed limits; and - transmitting an actuator signal to the actuator (220, 250) to cause the actuator to generate the operating torque on the at least one wheel without exceeding a rotational speed limit of the actuator.

[0310] Example 11. The motion support system (230) of Example 10, wherein the current vehicle powertrain state is one of: a current vehicle transmission state, a gear position of the vehicle transmission, or a transmission clutch actuation state.

[0311] Example 12. A motion support system (230) according to any one of Examples 10 or 11, wherein the wheel motion system (230) is a decentralized wheel motion system (230) that can be connected to a wheel-specific actuator, and the wheel-specific actuator is configured to control a single wheel of the vehicle.

[0312] Example 13. A method for controlling an actuator of a vehicle, the actuator being configured to apply a torque on at least one wheel (210) of the vehicle, wherein the method comprises: - determining (S1) a desired torque for operating said vehicle under current vehicle operating conditions; - determining (S2) a wheel slip ratio limit of said at least one wheel of said vehicle; - determining (S3) a wheel speed limit of the at least one wheel of the vehicle based at least on the wheel slip rate limit; - determining (S4) an operating torque and an actuator rotational speed limit based on the desired torque, said wheel speed limit and the current vehicle driveline state; and - controlling (S5) the actuator to generate the operating torque on the at least one wheel without exceeding a rotational speed limit of the actuator.

[0313] Example 14. A control signal representing an instruction to be executed by a motion support system (230), the control signal comprising: - a torque component that enables the motion support system (230) to determine an operating torque; and - a wheel speed limit component representing wheel speed limit data that, when executed by the motion support system (230), causes the motion support system (230) to generate an actuator signal corresponding to the operating torque subject to an actuator rotation speed limit, the actuator rotation speed limit being determinable based on the wheel speed limit component in consideration of a current vehicle powertrain state.

Claims

1. A control unit (130, 140) for controlling a heavy vehicle (100), in, The control unit is arranged to: obtain input data indicative of desired wheel forces (Fx, Fy) to be generated by at least one wheel (210) of the vehicle (100), and Based on the inverse tire model (f -1 ) converting the input data into corresponding equivalent wheel speeds or wheel slips to be maintained by the wheels (210) to generate desired wheel forces (Fx, Fy), wherein the control unit (130, 140) is arranged to obtain the inverse tire model according to the current operating condition of the wheel (210), and The control unit (130, 140) is arranged to control the heavy vehicle (100) based on the equivalent wheel speed or wheel slip and / or based on a wheel speed limit or wheel slip limit associated with the equivalent wheel speed or wheel slip.

2. The control unit (130, 140) according to claim 1, wherein The control unit is further arranged to assign a steering angle ( ).

3. The control unit (130, 140) according to claim 1 or 2, wherein: The data indicative of desired wheel forces (Fx, Fy) include desired wheel torque (Treq) and wheel rolling radius (R).

4. The control unit (130, 140) according to any one of claims 1 to 3, wherein: The current operating condition includes vehicle-level force distribution (Fx, Fy, Mz) and / or wheel ground velocity vectors (Vx, Vy).

5. The control unit (130, 140) according to any one of claims 1 to 4, wherein: The current operating condition includes the normal load (Fz) of the wheel (210).

6. The control unit (130, 140) according to any one of claims 1 to 5, wherein: The current operating condition includes an estimated tire stiffness (Cest) of the wheel (210).

7. The control unit (130, 140) according to any one of claims 1 to 6, wherein: The current operating condition includes a tire-road friction coefficient associated with the wheel ( ).

8. The control unit (130, 140) according to any one of claims 1 to 7, wherein: The current operating condition includes a minimum required lateral force capability (Fy,min) of the wheel (210).

9. The control unit (130, 140) according to any one of claims 1 to 8, wherein: The current operating condition includes a maximum allowable lateral slip angle (α) of the wheel (210).

10. The control unit (130, 140) according to any one of claims 1 to 9, wherein: The inverse tire model (f -1 ) is configured to provide a residual lateral force capacity (Fy, rem) of the wheel (210).

11. The control unit (130, 140) according to any one of claims 1 to 10, wherein: The inverse tire model (f -1 ) is configured to provide a gradient (dFx, dFy) of a desired wheel force relative to a wheel speed or wheel slip at a tire operating point associated with the desired wheel force and at the current operating condition of the wheel (210).

12. The control unit (130, 140) according to any one of claims 1 to 11, wherein: The control unit is arranged to store a predetermined inverse tire model (f -1 ), wherein the inverse tire model is stored in the memory as a function of the current operating condition of the wheel (210).

13. The control unit (130, 140) according to any one of claims 1 to 12, wherein: The control unit is arranged to adapt the inverse tire model (f) based on the measured wheel behavior and / or vehicle behavior in response to controlling the heavy vehicle (100) based on the equivalent wheel speed or wheel slip. -1 ) .

14. The control unit (130, 140) according to claim 13, wherein The inverse tire model (f -1 ) is adjusted to always be within a predetermined upper and / or lower limit of the tire force according to the wheel slip rate or wheel speed.

15. The control unit (130, 140) according to any one of claims 1 to 14, wherein: The control unit is arranged to convert the inverse tire model (f -1 ) is represented as a lookup table.

16. The control unit (130, 140) according to any one of claims 1 to 14, wherein: The control unit is arranged to convert the inverse tire model (f -1 ) is represented as a neural network.

17. A method for controlling a heavy vehicle (100) executed in a control unit (130, 140), the method comprising: obtaining (SA1) input data indicative of desired wheel forces (Fx, Fy) to be generated by at least one wheel (210) of the vehicle (100), Obtain (SA2) an inverse tire model (f associated with the wheel (210) -1 ), wherein the inverse tire model depends on the current operating condition of the wheel (210), and converting (SA3) the input data into corresponding equivalent wheel speeds or wheel slips to be maintained by the wheel (210) based on an inverse tire model of the wheel (210) to produce desired wheel forces (Fx, Fy), and The heavy vehicle (100) is controlled (SA4) based on the equivalent wheel speed or wheel slip and / or based on a wheel speed limit or wheel slip limit associated with the equivalent wheel speed or wheel slip.

18. A method for moving a heavy vehicle (100), the method comprising: obtaining (SB1) a motion instruction for moving the vehicle (100), Determine (SB2) a target wheel slip ratio limit value (λ) associated with a wheel slip ratio suitable for executing the motion command. target ),as well as The wheel speed (ω) is controlled (SB3) so that the wheel slip ratio of the vehicle (100) remains below the target wheel slip ratio limit value (λ target ).

19. The method according to claim 18, comprising controlling (SB31) the wheel speed (ω) so as to keep the wheel slip ratio of the corresponding wheel of the vehicle (100) below the target wheel slip ratio limit value (λ) based on the following relationship: target ): in, represents the wheel speed, Indicates the target wheel slip rate limit value, is the reference speed, is the vehicle speed in the wheel reference frame, and Indicates the wheel radius.

20. The method according to claim 18 or 19, wherein The movement instruction (SB11) includes an acceleration (a) requested by the vehicle (100) req ), and wherein the target wheel slip ratio limit (λ target ) is determined (SB21) based on the longitudinal force (Fx′) required to achieve the requested acceleration.

21. The method according to claim 20, comprising: The target wheel slip ratio limit value (λ) is determined (SB212) based on the longitudinal force (Fx') required to achieve the requested acceleration and based on a predetermined relationship (400) between the lateral force (Fy) and the longitudinal wheel slip ratio. target ).

22. The method according to claim 20 or 21, comprising: Based on the relationship Fx'=m*a req to determine (SB211) the longitudinal force (Fx') required to achieve the requested acceleration, where m is the mass of the vehicle (100) and a req is the acceleration requested of the vehicle (100).

23. The method according to claim 21 or 22, wherein The predetermined relationship (400) between the longitudinal force (Fx) and the longitudinal wheel slip is pre-configured (SB213) based on estimated road conditions.

24. The method according to claim 18 or 19, wherein The movement instruction (SB12) includes the final speed (v req ), and wherein the target wheel slip ratio limit (λ target ) is the pre-configured wheel slip limit value (SB22).

25. The method according to claim 24, comprising controlling (SB311) the wheel speed (ω) so as to keep the wheel slip ratio of the vehicle (100) below the target wheel slip ratio limit value based on the following relationship: ) : in, is set to the final speed (v req ).

26. The method according to any one of claims 18 to 25, comprising controlling (SB32) the wheel speed (ω) to keep the vehicle acceleration below a preconfigured maximum acceleration value.

27. The method according to any one of claims 18 to 26, comprising controlling (SB33) the wheel speed (ω) to keep the wheel speed below a preconfigured maximum wheel speed value.

28. The method according to any one of claims 18 to 27, comprising: At vehicle speed ( ) is above the configured threshold speed ( ), controlling (SB34) the vehicle speed ( ).

29. The method according to any one of claims 18 to 28, wherein: The movement instruction (SB13) includes a distance (d req ), the method includes integrating the wheel speed with respect to time (SB4) to obtain the following distance (d req ):

30. The method according to any one of claims 18 to 29, wherein The motion command corresponds to a request for a peak torque to be applied within a finite period of time.

31. The method according to any one of claims 18 to 30, comprising transmitting (SB5) a wheel speed request to an electric machine connected to the drive wheels via an open differential arrangement, wherein The method includes controlling the wheel speed (ω) by the motor so that the wheel slip ratio of the vehicle (100) is kept below the target wheel slip ratio limit value (λ target ).

32. The method according to any one of claims 18 to 31, comprising: The target wheel slip ratio limit value (λ target ) increases from an initial value to a predetermined final value.

33. A method for controlling at least one actuator (220, 250) of a vehicle (100), the actuator (220, 250) being configured to apply a torque on at least one wheel (210) of the vehicle (100), wherein: The applied torque is determined by a control function associated with a control bandwidth, the method comprising: - configuring (SC1) the control function to control the applied torque so as to reduce a difference between a first parameter value and a second parameter value, the first parameter value being related to a current rotational speed of the wheel (210) and the second parameter value being related to a target rotational speed limit of the wheel (210); - obtaining (SC2) data indicative of a current operating condition of said vehicle; - setting (SC3) the control bandwidth of the control function according to the current operating condition of the vehicle (100); and - controlling (SC4) the actuator (220, 250) using the control function.

34. A method for controlling at least one actuator (220, 250) to apply torque to at least one wheel (210) of a vehicle (100) performed in an actuator control system, the actuator control system comprising a control function, wherein: The applied torque is determined by the control function in association with a control bandwidth, the method comprising: - determining (SC10) a first parameter value, the first parameter value being related to a current rotational speed of the wheel (210); - configuring (SC20) the control function to control the applied torque so as to reduce a difference between the first parameter value and a second parameter value, the second parameter value being related to a target rotational speed of the wheel (210); - obtaining (SC30) data indicative of a current operating condition of said vehicle; - setting (SC40) the control bandwidth of the control function according to the current operating condition of the vehicle; and - controlling (SC50) the actuator using the control function.

35. The method according to claim 34, wherein The control function is configured to control the speed of the actuator (220, 250).

36. The method according to any one of claims 34 or 35, wherein The increased bandwidth of the control function is associated with an increased torque response of the actuator.

37. The method according to any one of claims 34 to 36, wherein: The control bandwidth of the control function is controlled using a predetermined set of feedback gains for the actuator, each feedback gain being associated with a specific operating condition of the vehicle.

38. The method of claim 37, wherein: The control function is a PID controller.

39. The method according to any one of claims 34 to 38, wherein The control function is a proportional controller, and the method further comprises: - obtaining a signal indicative of a target bandwidth for said control function; and - configuring the control function using the target bandwidth and a scaling parameter related to the current operating condition of the vehicle.

40. A method performed in a vehicle motion management system (260) of a vehicle (100), the vehicle motion management system being connectable to an actuator control system for transmitting control signals between the vehicle motion management system and the actuator control system, the method comprising: - obtaining (SC100) the current speed of the vehicle (100); - determining (SC200) the current operating status of the vehicle (100); as well as - transmitting (SC300) a control signal to the actuator control system, the control signal representing an instruction that, when executed by the actuator control system, causes a control function of the actuator control system to apply a torque to at least one wheel of the vehicle in association with a control bandwidth to reduce a difference between a first parameter value and a second parameter value, the first parameter value being associated with a current rotational speed of the wheel based on a current speed of the vehicle and the second parameter value being associated with a target rotational speed of the wheel, the control bandwidth being determinable based on the current operating condition of the vehicle.

41. The method of claim 40, further comprising: - determining a target speed of the vehicle based on the current operating condition, wherein the target rotational speed of the wheel is based on the target speed of the vehicle.

42. The method according to any one of claims 40 or 41, further comprising: - determining a desired operating performance of the vehicle based on the current operating conditions, wherein the control bandwidth can be further determined according to the desired operating performance of the vehicle.

43. The method according to any one of claims 40 to 42, further comprising: - Determine target bandwidth; as well as - transmitting the control signal comprising the determined target bandwidth, wherein the control bandwidth is further determinable based on the target bandwidth.

44. The method according to any one of claims 40 to 43, wherein: The current operating condition of the vehicle is based on at least one of a current vehicle condition and a current road condition on which the vehicle is operating.

45. The method according to any one of claims 40 to 44, wherein The current operating condition is at least one of: a current vehicle mass, an inclination of a road on which the vehicle is operating, a vehicle speed, a friction level between wheels of the vehicle and a road surface, and a current tire stiffness.

46. ​​An actuator control system for a vehicle (100), the actuator control system being configured to control at least an actuator (220, 250) to apply torque to at least one wheel of the vehicle, the actuator control system comprising a control function, wherein The applied torque is determined by the control function in association with the control bandwidth, the actuator control system being configured to: - determining a first parameter value, said first parameter value being related to a current rotational speed of said wheel; - configuring the control function to control the applied torque so as to reduce a difference between the first parameter value and a second parameter value, the second parameter value being related to a target rotational speed of the wheel; - obtaining data indicative of the current operating condition of said vehicle; - setting the control bandwidth of the control function according to the current operating condition of the vehicle; as well as - Controlling the actuator using the control function.

47. A vehicle motion management system (260) of a vehicle (100), the vehicle motion management system (260) being connectable to an actuator control system for transmitting control signals between the vehicle motion management system and the actuator control system, wherein: The vehicle motion management system is configured to: - Get the current speed of the vehicle; - determining the current operating condition of said vehicle; as well as - transmitting a control signal to the actuator control system, the control signal representing an instruction that, when executed by the actuator control system, causes a control function of the actuator control system to apply a torque to at least one wheel of the vehicle in association with a control bandwidth determined based on the current operating condition of the vehicle to reduce a difference between a first parameter value associated with a current rotational speed of the wheel and a second parameter value associated with a target rotational speed of the wheel.

48. A control signal representing an instruction to be executed by an actuator control system of a vehicle (100), the control signal comprising: - a vehicle speed component, said vehicle speed component enabling said actuator control system to determine a current rotational speed of said wheel (210); as well as and a vehicle operating condition component representing instructions that, when executed by the actuator control system, cause a control function of the actuator control system to apply a torque to at least one wheel of the vehicle in association with a control bandwidth to reduce a difference between a first parameter value associated with a current rotational speed of the wheel based on a current speed of the vehicle and a second parameter value associated with a target rotational speed of the wheel, the control bandwidth being determinable based on the current operating condition of the vehicle.

49. A control unit (130, 140) for controlling a vehicle wheel (210) provided with a tire (1502), wherein: The control unit comprises or is operatively connected to a data storage device (820) having a stored tire model (400) for the tire, wherein in the tire model the longitudinal tire force (Fx) is represented as a function of at least a longitudinal wheel slip (λ), the longitudinal wheel slip being dependent on the rotational speed of the wheel and the speed of the vehicle, Wherein, the control unit is configured to: - receiving at least one tire parameter input comprising a measured value of at least one parameter affecting the longitudinal slip stiffness of the tire, - correcting said function in the stored tire model based on the received tire parameter input, - obtain or generate wheel torque requests, - converting the obtained or generated wheel torque request into a wheel rotational speed limit request based on the corrected function, and - sending the wheel rotation speed limit request to an actuator to provide a rotation speed of the wheel that is lower than the wheel rotation speed limit request.

50. The control unit (130, 140) according to claim 49, wherein The at least one parameter is selected from the group consisting of: - Age of the tire (t act ), - Ambient temperature (T act ), - the inflation pressure of the tire (P act ), - the normal load of the tire, and - the wear of the tire, suitably approximated as the distance travelled by the tire (d act ) .

51. The control unit (130, 140) according to any one of claims 49-50, wherein The control unit is configured to apply a slip stiffness correction factor (c p 、c T 、c a 、c w ) to correct the function, the slip stiffness correction factor having a change relative to the parameter.

52. The control unit (130, 140) according to any one of claims 49 to 51, wherein The control unit is configured to receive a plurality of different tire parameter inputs, each tire parameter input comprising a measured value of a corresponding one of a plurality of parameters affecting the longitudinal slip stiffness of the tire, wherein the control unit is configured to correct the function in a stored tire model (400) by applying a combined correction factor to the function, the combined correction factor being a function of a plurality of slip stiffness correction factors, wherein each slip stiffness correction factor has a variation relative to a corresponding one of the plurality of parameters.

53. The control unit (130, 140) according to any one of claims 49 to 52, wherein The at least one tire parameter input is a primary tire parameter input and the at least one parameter is a primary parameter, wherein the control unit is further configured to correct the function in the stored tire model (400) based on at least one secondary tire parameter input, the secondary tire parameter input comprising a measured value of at least one secondary parameter, the at least one secondary parameter being selected from the group consisting of: - rolling radius, - Nominal peak friction, and - Rolling resistance coefficient.

54. The control unit (130, 140) according to any one of claims 49 to 53, wherein When the control unit converts the wheel torque request into the wheel rotational speed request, the control unit is configured to calculate a slip ratio request based on the corrected function, and convert the slip ratio request into the wheel rotational speed request using the following slip ratio formula: where λ is the longitudinal wheel slip, where Rω is the rotational speed of the wheel, where is the wheel radius in meters, and ω is the angular velocity of the wheel, and where V x is the longitudinal velocity of the wheel.

55. A method for controlling torque applied to a wheel of a vehicle provided with a tire, comprising: - receiving (SD1) at least one tire parameter input, said tire parameter input comprising a measured value of at least one parameter influencing the longitudinal slip stiffness of said tire, - correcting (SD2) a tire model of the tire based on the received tire parameter input, wherein in the tire model, longitudinal tire force is represented as a function of longitudinal wheel slip, the longitudinal wheel slip being dependent on the rotational speed of the wheel and the speed of the vehicle, wherein the step of correcting the tire model comprises correcting the function, - obtain or generate (SD3) wheel torque request, - converting (SD4) the obtained or generated wheel torque request into a wheel rotational speed request based on the corrected function, and - sending (SD5) the wheel rotational speed request or the associated wheel speed limit to an actuator to provide a rotational speed of the wheel corresponding to the wheel rotational speed request or wheel speed limit request.

56. The method of claim 55, wherein: The at least one parameter is selected from the group consisting of: - the age of the tire, - Ambient temperature, - the inflation pressure of the tire, - the normal load of the tire, and - the wear of the tyre, suitably approximated by the distance travelled by the tyre.

57. The method according to any one of claims 55-56, wherein The corrective (SD2) action comprises applying a slip stiffness correction factor to the function, the slip stiffness correction factor having a variation with respect to the parameter.

58. A method according to any one of claims 55 to 57, comprising: - receiving a plurality of different tire parameter inputs, each tire parameter input comprising a measured value of a respective one of a plurality of parameters affecting the longitudinal slip stiffness of the tire, wherein the step of correcting comprises applying a combined correction factor to the function, the combined correction factor being a function of a plurality of slip stiffness correction factors, wherein each slip stiffness correction factor has a variation relative to a respective one of the plurality of parameters.

59. The method according to any one of claims 55 to 58, wherein The at least one tire parameter input is a primary tire parameter input and the at least one parameter is a primary parameter, wherein the act of correcting (SD2) comprises correcting the function in the stored tire model based on at least one secondary tire parameter input, the secondary tire parameter input comprising a measured value of at least one secondary parameter, the at least one secondary parameter selected from the group consisting of: - rolling radius, - Nominal peak friction, and - Rolling resistance coefficient.

60. The method according to any one of claims 55 to 59, wherein The converting (SD4) includes calculating a slip ratio limit request based on the corrected function, and converting the slip ratio limit request into the wheel rotation speed limit request using the following slip ratio formula: where λ is the longitudinal wheel slip, where Rω is the rotational speed of the wheel, where is the wheel radius in meters, ω is the angular velocity of the wheel, and where V x is the longitudinal velocity of the wheel.

61. A kit (1500) comprising a tire (1502) and a tire model signal (1504) adapted to generate a value of longitudinal tire force as a function of longitudinal wheel slip of the tire when the tire is mounted on a vehicle.

62. A control unit (130, 140) for controlling a heavy vehicle (100), in, The control unit is arranged to obtain an acceleration profile (a req ) and curvature distribution map (c req ), the acceleration distribution diagram (a req ) and curvature distribution map (c req ) indicates a desired maneuver of the vehicle (100), The control unit (130, 140) includes a force generation module (310) configured to determine a set of global vehicle forces and moments required to perform a desired maneuver, The control unit (130, 140) further comprises a motion support device (MSD) coordination module (320) arranged to coordinate one or more MSDs to collectively provide the set of global vehicle forces and moments by generating one or more corresponding wheel forces, and an inverse tire model function block (330) configured to map the one or more wheel forces to an equivalent wheel slip (λ), Wherein the control unit (130, 140) is arranged to request wheel slip limits from the MSD based on the wheel slip (λ) in order to control the heavy vehicle during a desired maneuver.

63. The control unit (130, 140) according to claim 62, further being arranged to: ) is lower than the first threshold (v low ), the request is as follows: wheel speed and vehicle ground speed ( ) offset( ) of the wheel slip ratio (λ).

64. The control unit (130, 140) according to claim 63, wherein The desired wheel speed (ω) to be maintained by the MSD w ) is determined to be: in, is the vehicle ground speed, is the wheel radius, is the wheel speed offset, and is the accelerator pedal position value between 0 and 1.

65. The control unit (130, 140) according to claim 64, wherein The wheel speed offset is a gain factor associated with the driver's preference and / or based on low speed excursion limit Sure.

66. A control unit (130, 140) according to any one of claims 62-65, arranged to control the vehicle's ground speed ( ) is higher than the second threshold (v high ) is requested as the wheel speed The vehicle's ground speed ( ) is the wheel slip ratio limit (λ) of the normalized difference between .

67. The control unit (130, 140) according to claim 66, wherein The desired wheel speed to be maintained by the MSD ( ) is determined to be: or in, is the vehicle ground speed, is the wheel radius, and is the requested wheel slip.

68. A control unit (130, 140) according to claim 66 or 67, wherein The second threshold (v high ) is equal to the first threshold (v low ).

69. A control unit (130, 140) according to claim 66 or 67, wherein The second threshold (v high ) and the first threshold (v low ) deviates from a predetermined speed value, wherein the control unit is arranged to request the following wheel behavior if the vehicle speed is between the first threshold and the second threshold: the wheel behavior represents a wheel speed corresponding to the speed deviation (ω w ) and the wheel speed corresponding to the difference in wheel speed relative to the ground speed.

70. The control unit (130, 140) according to any one of claims 62-69, wherein The control unit is arranged to receive data indicative of capabilities of one or more MSDs and to verify whether the requested wheel slip (λ) is within capabilities of the respective MSD.

71. A motion support device (MSD) control unit (230) for a heavy vehicle (100), the MSD control unit (230) being configured to control one or more MSDs (220, 250) associated with at least one wheel (210) on the vehicle (100), in, The MSD control unit (230) is arranged to be communicatively coupled (265) to a vehicle motion management (VMM) unit (260) for receiving control commands from the VMM unit (260), the control commands including wheel speed limit requests and / or wheel slip limit requests for controlling vehicle motion via the one or more MSDs (220, 250), wherein the MSD control unit (230) is arranged to obtain a capability range indicating a range of wheel behavior of the wheel (210), for which the VMM unit (260) is allowed to influence the behavior of the wheel by means of the control command, and wherein the MSD control unit (230) is arranged to monitor wheel behavior and detect whether the wheel behavior is outside the capability range, The MSD control unit (230) is arranged to trigger a control intervention function if the monitored wheel behavior is outside the capability range.

72. The MSD control unit (230) of claim 71, wherein: The one or more MSDs include at least one service brake (220) arranged to generate negative torque through the wheels (210).

73. The MSD control unit (230) of claim 71 or 72, wherein: The one or more MSDs include at least one propulsion unit (250) arranged to generate positive torque and / or negative torque through the wheels (210).

74. The MSD control unit (230) according to any one of claims 71-73, wherein The capability range includes upper limits on permissible positive and / or negative longitudinal wheel slip and / or wheel rotational speed.

75. The MSD control unit (230) according to any one of claims 71-74, wherein The capability range includes upper limits for permissible positive and / or negative longitudinal wheel accelerations.

76. The MSD control unit (230) according to any one of claims 71-75, wherein The capability range includes upper limits on permissible positive and / or negative vehicle yaw rates.

77. The MSD control unit (230) according to any one of claims 71-76, wherein The capability range includes lower limits for permissible positive and / or negative longitudinal wheel slip and / or wheel rotational speed.

78. The MSD control unit (230) according to any one of claims 71-77, wherein The capability range includes a lower limit for permissible positive and / or negative longitudinal wheel accelerations.

79. The MSD control unit (230) according to any one of claims 71-78, wherein The capability range includes a lower limit on permissible positive and / or negative vehicle yaw rates.

80. The MSD control unit (230) according to any one of claims 71-79, being arranged to receive wheel speed data associated with the wheel (210) from a wheel speed sensor (240), and to detect whether the wheel behavior is outside the capability range based on the wheel speed data.

81. An MSD control unit (230) according to any of claims 71-80, arranged to obtain fixed capability ranges as parameters loaded from a memory or received from an external configuration entity.

82. The MSD control unit (230) according to any of claims 71-81, arranged to continuously obtain an updated capability range.

83. The MSD control unit (230) according to any one of claims 71-82, wherein The controlling intervention function includes performing an intervention function by one or more of the MSDs (220, 250).

84. The MSD control unit (230) according to any one of claims 71-83, wherein The control intervention function includes triggering a request to an external arbitrator function for direct MSD control by the MSD control unit (230).

85. The MSD control unit (230) according to any one of claims 71-84, wherein The MSD control unit (230) is arranged to monitor the wheel behavior by filtering samples of the wheel behavior over time, and detect whether the wheel behavior is outside the capability range based on a result of the filtering.

86. A vehicle motion management (VMM) unit (260) arranged to perform vehicle motion management for controlling the motion of a heavy vehicle (100) via one or more motion support devices (MSD) (220, 250) associated with at least one wheel (210) on the vehicle (100), in, The VMM unit (260) is arranged to be communicatively coupled (265) to the MSD control unit (230) for transmitting control commands including wheel speed requests and / or wheel slip rate requests to the MSD control unit (230) to control vehicle motion via the one or more MSDs (220, 250), wherein the VMM unit (260) is arranged to obtain a capability range indicating a range of wheel behavior of the wheel (210), for which the VMM unit (260) is allowed to influence the behavior of the wheel by means of the control command, and The VMM unit (260) is arranged to generate the control command so that the wheel behavior is within the capability range.

87. The VMM unit (260) according to claim 86 comprises an arbitrator function, which is configured to receive a request for direct MSD control by the MSD control unit (230) and to give vehicle control to the MSD control unit (230) if the wheel behavior is outside a predetermined wheel behavior safety range.

88. A method for controlling the movement of a heavy vehicle (100), the method comprising: configuring (SF1) a motion support device MSD control unit (230) to control one or more MSDs (220, 250) associated with at least one wheel (210) on the vehicle (100), configuring (SF2) a vehicle motion management VMM unit (260) to perform vehicle motion management by the one or more MSDs (220, 250) via control commands transmitted to the MSD control unit (230), defining (SF3) a capability range, the capability range indicating a wheel behavior range of the wheel (210) for which the VMM unit (260) is allowed to influence the wheel behavior via the control command, Monitoring (SF4) wheel behavior, and In the event that the monitored wheel behavior is outside a defined capability range, a control intervention function is triggered (SF5) by the MSD control unit (230).

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