Improved vehicle motion control system and method

Abstract

The invention relates to a vehicle motion control system (100) of a vehicle having at least one steering system and one or more of a braking system (24) and a torque vectoring system, a plurality of sensors (11, 21) for sensing at least a vehicle speed or wheel speed, yaw velocity and wheel angle, the vehicle motion control system includes a yaw stability control (YSC) function that includes an oversteer control function, where the YSC function is disposed to be fail-operable.

Description

Technical Field

[0001] The invention relates to a vehicle motion control system having the features of the first part of claim 1. The invention also relates to a vehicle motion control method having the features of the first part of claim 24, and a vehicle comprising such a motion control system. Background Art

[0002] Ground vehicles (e.g. passenger cars) are prone to instability, for example when performing evasive maneuvers or driving in low μ (friction coefficient) conditions, such as when there is ice or water on the road. Therefore, since the early 1990s, they have been equipped with yaw stability control (YSC) functions, such as ESP TM (Electronic Stability Program). When the vehicle becomes unstable, it can cause oversteer, which is difficult for the driver to handle. The purpose of YSC is to stabilize the vehicle to enable the driver to maintain control of the vehicle, also for less skilled drivers. With the introduction of YSC, the number of fatalities was temporarily reduced by more than 30%. However, the number of fatalities later began to increase again, at least in part as a result of drivers using the functions of YSC to stretch the limits of controllable driving, as discussed further below.

[0003] Often, to make the task of controlling the vehicle easier, vehicles are built to have understeering behavior. This means that they tend to steer less than the driver intends. This understeering behavior is not necessarily good for path following, but it makes it easier for the driver to avoid instabilities such as oversteering, which can lead to loss of control.

[0004] With the introduction of YSC, initially the vehicles did not understeer less. But over time, the level of robustness and practicality improved, and decades later, vehicles were made less prone to understeer and therefore more prone to instability.

[0005] At the same time, early YSC was rather abrupt in its control and therefore not very comfortable. As a result, drivers tended to avoid getting into situations where YSC was activated. This is thought to be a significant reason why the number of fatalities dropped significantly at first. However, over time, YSC has evolved and become very smooth in its control, with the result that drivers tend to increase speed and "take advantage of" or rather misuse YSC in their normal driving, causing the number of fatalities to increase again, almost to the same level before the introduction of YSC. Furthermore, in fact, many drivers today may not even have the experience of driving a vehicle without active YSC.

[0006] Therefore, any position that the driver is responsible and should be able to take control of the vehicle at any time in the event of a sudden loss of YSC is inherently in conflict with the real world, where drivers who have been trained in the behavior of a vehicle with active YSC have come to rely on the system to extend the vehicle's capabilities. In particular, in such uses of YSC, a failure of YSC would lead to danger, and more generally, a function designed for driving performance (YSC) could lead to its "misuse" which could actually involve risks and, in some cases, actually lead to the risk of an increased number of fatalities.

[0007] YSC is used for the lateral (or directional) stability of the vehicle. When the vehicle is operating under conditions where the slip angle is below the limit and with neutral steering, the relationship between the yaw rate and the steering wheel angle is essentially linear; the yaw rate is the product of the steering wheel angle and the yaw rate gain. In addition, for a neutral steering vehicle with negligible slip angle, the yaw rate is given by the lateral acceleration divided by the vehicle speed. These relationships can be used to set the ideal yaw rate for a given condition. The actual yaw rate is measured using a yaw rate sensor, and the difference between the actual yaw rate and the ideal yaw rate is used to control yaw stability.

[0008] However, YSC is not designed as a safety-critical system in the context of safety standard ISO 26262, which is the automotive industry standard under which potentially hazardous functions and / or systems are developed and provides recommendations on what is considered to be the state-of-the-art for designing safety-related functions.

[0009] Regardless of whether the driver is considered responsible (which is not the case in ISO 26262), it has been recognised that controllability in the event of a failure, as suggested in ISO 26262, is not sufficient. ISO 26262 only considers controllability in the event of a failure of the YSC.

[0010] Furthermore, current safety standards are developed for manually driven vehicles, taking into account the controllability of the driver to be able to handle certain situations. The problem will become even bigger with the introduction of self-driving cars, as they will have an autonomous "driver" (autopilot), usually based on artificial intelligence that is trained on a large data set from normal drivers. This means that the autopilot is actually at the same level as a normal driver, or even worse, and even normal drivers cannot handle oversteer very well. Furthermore, for path planning of self-driving cars, the sensors used can be cameras, radars, lidars. Such sensors are slow and require a lot of slow signal processing and filtering. Therefore, the path planner cannot be used as a means to avoid oversteer.

[0011] Recently, with the development of vehicle electrification, hybrid vehicles and fully electric vehicles have emerged. On hybrid vehicles and electric vehicles, there is often an electric motor on the rear axle. For hybrid vehicles, the reason for arranging the electric motor on the rear axle is that, for cost reasons, the vehicle can be driven on all four wheels if the combustion engine is driven on the front axle. Another reason for rear-axle drive is better acceleration. However, considering the rear-axle electric drive, regeneration is also required on the rear axle, because the electric motor can easily be used as a generator. However, when the rear axle is used as a generator, the risk of losing grip on the rear axle is even greater. This can occur especially on slippery surfaces like snow and ice, but also on wet roads. This means that regeneration can also be dangerous.

[0012] However, it has been realised that the original motivation that it was correct and ethical that the system did not have to be developed as a safety-critical system is no longer actually valid. Summary of the invention

[0013] It is therefore an object of the present invention to provide an improved vehicle motion control system by which one or more of the above problems may be solved and one or more of the above disadvantages may be overcome.

[0014] A particular object of the present invention is to provide an improved vehicle motion control system by which safety can be improved.

[0015] In particular, it is an object to provide a vehicle motion control system by which enhanced safety is provided that is independent of the driver's skills and experience and / or the driver's use of the YSC functionality.

[0016] More particularly, an object is to provide a vehicle motion control system by which the risk of fatality in the event of a YSC failure can be reduced.

[0017] More particularly, an object is to provide a vehicle motion control system by which the oversteering effects occurring due to road conditions or evasive maneuvers as well as the understeering effects generated by the YSC can be handled in a safe manner.

[0018] A particular object is to provide a vehicle motion control system by which the controllability and safety of an autonomous vehicle can be enhanced.

[0019] Another particular object is to provide a vehicle motion control system by which the controllability and safety of an electric, hybrid or fully electric vehicle can be enhanced.

[0020] Furthermore, a particular object is to provide a vehicle motion control system by means of which the risk of introducing controllability hazards in slippery road conditions or hazards associated with electric motor regeneration at the rear axle for a hybrid or fully electric vehicle can be reduced.

[0021] Furthermore, a particular object is to provide a vehicle motion control system that is reliable and safe under different conditions.

[0022] Other specific objects are to provide a vehicle motion control system that is cheap and easy to implement and manufacture, and that can be used for different types of vehicles, vehicles powered by conventional fuels, electric vehicles, hybrid vehicles, autonomous vehicles, and for conventional steering systems as well as power-assisted steer-by-wire (SbW) steering systems.

[0023] Another object is to provide a vehicle motion control method, by which one or more of the above objects can be achieved.

[0024] Another object of the present invention is to provide a vehicle with a vehicle motion control system, through which one or more of the above objects are achieved.

[0025] Therefore, there is provided a vehicle motion control system as initially mentioned having the characterizing features of claim 1. Therefore, there is also provided a vehicle motion control method having the characterizing features of claim 24 and a vehicle comprising such a motion control system.

[0026] Advantageous embodiments are given by the respectively attached dependent claims and are respectively described in the detailed description.

[0027] It will be appreciated that features of the invention may be combined in any combination without departing from the scope of the invention as defined by the accompanying claims. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] The present invention will now be further described in a non-limiting manner with reference to the accompanying drawings, in which:

[0029] Figure 1 is a schematic block diagram showing a vehicle motion control system according to a first embodiment of the present invention,

[0030] Figure 2 is a schematic block diagram showing a vehicle motion control system according to a second embodiment of the present invention,

[0031] Figure 3 is a schematic control scheme showing a general prior art implementation of vehicle motion control using a vehicle model and sensor fusion,

[0032] Figure 4 It shows that according to Figure 1A schematic control scheme of an exemplary embodiment of vehicle motion control in a vehicle motion control system with an embodiment of two separate sensor devices is shown,

[0033] Figure 5 It is shown that Figure 3 A schematic control scheme of an exemplary embodiment of vehicle motion control in a vehicle motion control system with a common sensor device is shown,

[0034] Figure 6 is a schematic control scheme showing implementation of vehicle motion control according to an embodiment with a fail-operable common sensor arrangement, and

[0035] Figure 7 is a schematic control scheme illustrating implementation of vehicle motion control according to an alternative embodiment with a fail-operable common sensor arrangement.

[0036] definition

[0037] To describe the present invention and facilitate understanding thereof, the following definitions are given, some of which will be relied upon in the detailed description of advantageous embodiments:

[0038] Function

[0039] Functions describe what the design will do or achieve, with an emphasis on input-output transformations. Each customer feature is a function: it will do or accomplish something for the customer. Functions are implemented by the system. As an example, the function of power-assisted steering is to provide steering assistance to the driver. The inputs to the power-assisted steering function are typically vehicle speed, steering wheel angle, and torsion bar torque, which are converted to assistance, as output, which is actuated by the power-assisted steering system.

[0040] Transformation: An operation on one or more states that results in one or more other states. This means that a transformation and its adjustable parameters can be used to create a relationship between input and output values ​​with an arbitrarily adjustable shape. A transformation can have parameters that vary over time and even depend on other values, so a transformation is a function whose parameters are themselves functions. An example of such a transformation is the vehicle speed-dependent assistance of a power-assisted steering system, whose inputs are vehicle speed, steering wheel angle and torsion bar torque. The assistance is calculated mathematically based on the inputs and the adjustment parameters. It can also often be implemented in hardware, as in the case of hydraulic power-assisted steering or a mix of both.

[0041] A subfunction is a part of a function. A function can be broken down into an infinite number of subfunctions in an infinite number of ways. The tasks that a function will accomplish are the sum of the tasks accomplished by its subfunctions.

[0042] The following sub-functions are used in the functional representation of the different embodiments:

[0043] Input signal sensing: The sub-function that obtains the sensor signal from the sensor subsystem. The input can be current, voltage or digital raw value, and the output is the sensor signal value.

[0044] Sensor fusion: A sub-function that derives a state verification signal from the information of several sensor signal values. For example, in the case of sensor fusion with fail-operability, the sub-function is, for example, the use of a "two out of three" mode, where three sensor signals are used and if the difference of one value exceeds a threshold, the output is based only on the other two signal values, resulting in an output that is verified and "fused" from several input signals.

[0045] Target calculation: A subfunction that obtains the control target value based on the input signal from sensor fusion.

[0046] Control: A subfunction that computes the assistance output, minimizing the control error between the target value computed by the target and the corresponding state signal from sensor fusion. The output is the assistance request.

[0047] Activate: Activates the sub-function of the assistance request.

[0048] Fail-operational is defined as the ability of a part (i.e., function, subfunction, system, or subsystem) to maintain its operation even if there is a single failure in the inputs to that part or in the subfunction / subsystem.

[0049] Fail-safe is defined as the ability of a part (i.e., function, sub-function, system, or subsystem) to detect a single failure in the inputs to that part or in the sub-function / subsystem and shut down its operation safely.

[0050] state

[0051] State: Multiple variables of a dynamic system that describe the state of the system at a given point in time.

[0052] The vehicle state is defined as the translational or rotational position, velocity or acceleration, or any state derived from these previously mentioned states, such as the vehicle slip angle, which is the angle between the vehicle's local x-axis and the vehicle velocity vector.

[0053] Vehicle axes and coordinate system where x is in the horizontal plane and in the forward direction of travel, y is in the horizontal plane, perpendicular to x and pointing to the left. z points upward.

[0054] Yaw direction: Rotation about the vehicle's z-axis, which points upward and is perpendicular to the vehicle's xy plane.

[0055] Lateral direction: The vehicle's y-axis, pointing to the left and perpendicular to the xz plane.

[0056] Longitudinal direction: The x-axis of the vehicle, pointing forward and perpendicular to the yz plane.

[0057] Straight-ahead position: The position of the steering wheel when the vehicle is moving straight along the x-direction.

[0058] Slip Angle: The lateral velocity of the vehicle divided by the longitudinal velocity of the vehicle.

[0059] Vehicle yaw state: The yaw position, yaw angular velocity or yaw acceleration of the vehicle at a given point in time.

[0060] Lateral vehicle state: The lateral position, lateral velocity, or lateral acceleration of the vehicle at a given point in time. Since the slip angle is the lateral velocity of the vehicle divided by the longitudinal velocity, the lateral vehicle state implicitly includes the slip angle.

[0061] Yaw and / or Lateral Vehicle State: Any yaw state and / or any lateral vehicle state (including slip angle) and any linear combination of all these states.

[0062] The steering angle is the angle in the steering system that affects the lateral acceleration or curvature of the vehicle, measured somewhere in the steering system, where such a steering angle can be:

[0063] -Front wheel angle, e.g. in the case of Ackermann steering, the steering angle is defined as the average of the two front wheel angles.

[0064] -The articulation angle of an articulated vehicle.

[0065] - In the case of a vehicle with rear wheel steering, the rear wheel steering angle.

[0066] - In the case of an all-wheel steering vehicle, a combination of the front wheel angle and the rear wheel angle.

[0067] - It can also be measured elsewhere in the steering system, such as the steering column, then multiplied by the ratio between the steering column and the wheels and modified as necessary for other setups.

[0068] Torsion bar torque is the torque measured using a sensor that is sensitive to the twisting of a specific torsion bar mounted somewhere on the steering column.

[0069] Steering wheel torque is the torque generated by the force applied by the driver to the steering wheel. This steering wheel torque is usually approximated by the torsion bar torque and / or obtained indirectly by monitoring the current to the steering feedback actuator.

[0070] Driver torque is equal to steering wheel torque.

[0071] Steering Torque: That portion of the torque applied by the driver through the steering wheel that corresponds to the vehicle state the driver wants to achieve. Steering wheel torque corresponds to several types of feedback, namely friction (from the tires and steering system), damping (from the tires and steering system), steering wheel self-centering due to the design of the front wheel suspension and steering system, and feedback from yaw and / or lateral vehicle state. Steering torque is the steering wheel torque with all feedback types except yaw and / or lateral vehicle state feedback removed.

[0072] Tire slip angle: The angle between the wheel direction and the direction of wheel movement.

[0073] Assist Torque: The torque applied by the steering actuator.

[0074] Degradation: If the YSC redundancy does not meet the fail-operable state, the output of the actual actuator or the output of other actuators is reduced, such as degradation of the maximum speed of the vehicle.

[0075] system

[0076] A system is a means to achieve a function. As an example, the function of power assisted steering is to provide steering assistance to the driver. The function output (assistance request) is actuated by the power assisted steering system.

[0077] Steering system: Different types of steering systems perform different functions. The steering system has the function of providing the driver with the steering position (steering angle) and steering feedback. The system for steering position has the function of influencing the steering angle.

[0078] List of steering systems related to the present invention:

[0079] EPS (Electric Power Steering) is a steering system with an actuator for electrically assisted steering.

[0080] Another specific type of steering system has an angle superposition actuator. An angle superposition actuator is an actuator that is used to achieve a relative angle somewhere in the steering column.

[0081] · Steer-by-wire system is a steering system where the steering column is replaced by wires. This type of system has two main parts, the steering feedback part, which is used to provide feedback torque to the driver, and the steering rack, which is used to provide the steering angle to the wheels.

[0082] Another type of steering system is that used for autonomous driving, where the feedback part may be completely removed in case of full automation (otherwise, the feedback part may be used, as in the case of steer-by-wire), but it has a steering rack to provide the steering angle to the wheels.

[0083] Braking system: The braking system has the function of providing wheel braking torque or force to each wheel.

[0084] Torque Vectoring: A system that provides positive (drive) and negative (braking) wheel torque to individual wheels. Torque vectoring is used to achieve torque vectoring in the yaw direction of the vehicle by using individual wheel motors or a controllable differential to differentiate the torque or force between the left and right sides to produce a yaw torque on the vehicle.

[0085] A subsystem is here, for example, a part, an element or an arrangement of a vehicle. Examples of subsystems of a steering system for electric power steering are a steering ECU, a steering assist motor, a steering column, a steering rack and the like.

[0086] An ECU is an electronic control unit that reads analog sensor signals and digital signals, which can be transmitted via, for example, a signal bus, performs any kind of calculation, for example, via sent analog or digital signals or by directly controlling, for example, an electric motor from a motor control stage, for example, performs control tasks and drives actuators.

[0087] Actuator

[0088] An actuator is a mechanism or system that is operated by mechanical means or an ECU and converts an energy source (usually electric current, hydraulic fluid pressure, or pneumatic pressure) into motion, force, or torque.

[0089] A vehicle state actuator is an actuator that affects one or several vehicle states when driven. Examples of vehicle state actuators are brake actuators, steering actuators, engines, controllable four-wheel drive clutches, controllable differentials, active dampers, electric or hydraulic wheel motors, and electrically or hydraulically driven axles.

[0090] Steering Actuator: A device that affects changes in the vehicle's yaw and / or lateral vehicle state.

[0091] EPS (Electric Power Steering) actuator is an actuator used for electric power steering.

[0092] The SbW (Steering by Wire) actuator is an actuator used for electric positioning steering.

[0093] An angle superposition actuator is an actuator used to achieve a relative angle somewhere in the steering column.

[0094] Brake Actuator: Wheel brakes that provide wheel torque or force to individual wheels.

[0095] Torque Vectoring Actuator: An actuator that provides positive (drive) and negative (braking) wheel torque to individual wheels by using individual wheel motors or a controllable differential to differentiate the torque or force between the left and right sides to create a yaw torque on the vehicle.

[0096] sensor

[0097] A torsion bar torque sensor is a sensor that is sensitive to the twisting of a torsion bar mounted somewhere in the steering column.

[0098] A torque and angle sensor (TAS) is a sensor used to sense torque and angle. It typically provides information about driver input and / or about the state of the steering subsystem.

[0099] ABS sensor or wheel speed sensor is a sensor that measures the rotational speed of the wheel. The wheel speed can be used to calculate vehicle status, such as vehicle speed and vehicle yaw rate.

[0100] The rate gyro sensor measures the angular velocity around an axis in the yaw, pitch or roll direction, for example, to sense the state of the vehicle and provide vehicle state information.

[0101] An acceleration sensor or accelerometer measures acceleration in the longitudinal, lateral or vertical direction, for example, to sense vehicle status and provide vehicle status information.

[0102] Position sensors measure position. It can be local, regional or global coverage; generally referred to as GPS, for example, sensing vehicle status, providing vehicle status information.

[0103] Signal

[0104] A signal bus is a transmission path through which signals can be read and / or transmitted.

[0105] The input signal may be, for example, a measurement of the torque generated by the force applied by the driver via the steering wheel, which torque is measured at the steering wheel or at a component mechanically connected to the steering wheel, or a signal from which this quantity can be derived.

[0106] control

[0107] Control of actuators: achieving a desired state in an actuator in a controlled manner.

[0108] Controller: An algorithm in a process that controls and seeks to keep a reference or target value in equilibrium by controlling the outcome through closed-loop and / or feedforward control. Controllability describes the ability of an external input to transfer the internal state of a system (actual value) from any initial state to any other final state (target value) within a finite time interval, thereby minimizing the difference between the target and actual values, i.e., the control error.

[0109] The vehicle state controller is defined as a dynamic function that achieves a target state in the vehicle in a controlled manner. That is, the difference between the target state and the actual state, i.e., the control error, is minimized in a controlled manner.

[0110] A target value, reference value or request is a set point for an actuator, which is achieved using a closed-loop controller and / or a feedforward controller.

[0111] The vehicle model is a mathematical model that converts wheel angles and vehicle velocity into a series of vehicle yaw and / or lateral states (eg, one or more of vehicle yaw rate and acceleration, vehicle lateral velocity and acceleration, and body slip angle).

[0112] Extended steering feedback torque is additional feedback that the driver should feel, such as tactile feedback or additional feedback for safety functions.

[0113] Torque and / or angle reference control (TAC) includes steering feel control (SFC) and / or steering position control (SPC), respectively. For steering feel control, the control of the steering wheel torque felt by the driver is the main content, while in steering position control, it is the control of the wheel angle, specifically, for front-wheel steering vehicles, the control of the front axle wheel angle, here called steering angle.

[0114] A feature is a combination of a function and a system that implements that function. In order to have a function, something must be done and achieved.

[0115] It should be clear that the present invention is not limited to any example vehicle state, subsystem state or driver input, nor is it limited to any example state. Different types of sensors and sensor arrangements may also be used to sense other or additional states, etc. DETAILED DESCRIPTION

[0116] According to the present invention, the YSC function is considered safety critical because, in general and among other things, the risk of a normal driver losing control of the vehicle occurs very frequently, which would have very serious consequences. The risk mitigation systems and / or functions must be run at a very high rate - typically not every 10 seconds. 7 A fault is generated once per hour, thus providing a structured functional safety design in which the YSC function is fail-operable.

[0117] As mentioned above, functions and / or systems with a dangerous potential are often developed in accordance with safety standards. In the automotive industry, standard ISO 26262 provides what are considered state-of-the-art recommendations for designing safety-related functions. If the risk of, for example, vehicle instability or lane departure is considered high risk, then the risk mitigation needs to be fail-operable in order to be considered sufficiently safe. Fail-operable functions and systems can be implemented in a number of different ways, of which redundancy is one, and some of the different modes of providing fail-operable systems or functions are described further below.

[0118] Figure 1 is a schematic block diagram of a first embodiment of a vehicle motion control system 100 having a fault-operable YSC function 100. The YSC function here includes a first YSC (yaw stability control) system 10 and a second YSC (yaw stability control) system 20. The first and second YSC 10, 20 are independent, and in one embodiment, both are fail-safe, allowing for faults, but are set to off if a fault is detected. The diagnostic coverage is high so that such faults are detected, which may cause danger. Since the first and second YSC systems / functions 10, 20 are independent, when one is turned off, the other will still work while maintaining sufficient safety. When only one system / function is used, a degraded mode, for example, can be provided, such as providing a warning to the driver, reducing speed or any other appropriate measures.

[0119] According to the invention, the first YSC 10 is arranged to control yaw stability by controlling steering, whereas the second YSC 20 is arranged to control yaw stability by controlling braking.

[0120] The first YSC system 10 comprises a steering control function, which comprises a steering ECU 12 with an oversteer control function 13 and comprises or is connected to a sensor device 11 comprising a plurality of sensors for directly measuring at least the vehicle speed, the yaw rate and the wheel angle or allowing calculation of at least the vehicle speed, the yaw rate and the wheel angle.

[0121] The sensor arrangement 11 comprises in particular a driver input sensor for sensing a steering wheel angle or any other angle in the steering system associated with the steering wheel or wheels, or a torsion bar torque sensor. The target values ​​of the driver's intended path or yaw and / or lateral vehicle state, the target yaw and / or lateral vehicle state can be calculated in either of two main ways, based on the steering angle or based on the steering torque, as also described below with reference to Figure 3Further description. The target yaw and / or lateral vehicle state can be calculated, for example, in the manner of EP2440442, and the steering angle can be used together with the vehicle model to obtain the driver's intended path. When the vehicle is operating under conditions where the tire slip angle is below a limit, the relationship between the yaw rate and the steering angle is essentially linear; the quasi-static yaw rate is the product of the steering angle and the yaw gain of the linear bicycle model. In addition, the yaw rate is given by the lateral acceleration divided by the vehicle speed. More generally, a linear or nonlinear, quasi-static or dynamic bicycle model (bicycle model) can be used to set the ideal yaw and / or lateral vehicle state for a given condition based on the steering angle and the vehicle speed. For the target yaw and / or lateral vehicle state based on the steering angle, the bicycle model is used as a dynamic function between the vehicle speed and the steering angle to give the target yaw and / or lateral vehicle state, i.e. the yaw and / or lateral vehicle state under ideal road conditions.

[0122] In other embodiments, the steering torque may be converted to a target yaw and / or lateral vehicle state, as also described below with reference to Figure 3 Further description.

[0123] The sensor arrangement 11 also includes a sensor for sensing the vehicle yaw rate and / or a sensor for sensing the vehicle lateral acceleration or other vehicle lateral state (eg yaw rate based on wheel speed).In some embodiments, two inputs are used in order to allow a plausibility check between them.

[0124] The oversteering control function of the steering ECU 12 is configured to minimize the error between the target and actual vehicle states by using the steering mechanism assist torque, or in the case of wire control or angle superposition, using the steering position, and is configured to control the steering mechanism 14 and provide a request to it, which the steering mechanism 14 will actuate with the aid of a steering actuator in order to minimize the vehicle state error by controlling the lateral force on the tire of the wheel 9 angle so that the vehicle assumes the desired direction.

[0125] The second YSC system 20 comprises a steering control function, which comprises a brake ECU 22 with an oversteer control function 23 and here comprises or is connected to a separate sensor device 21 comprising a plurality of sensors for directly measuring or allowing calculation of at least vehicle speed, yaw rate and wheel angle.

[0126] The sensor device 21 particularly includes a driver input sensor for sensing a steering wheel angle or any other angle related to the steering wheel or wheel in the steering system, or a torsion bar torque sensor. The driver's expected path can be calculated according to the method in EP2440442, that is, the angle can be used together with the vehicle model to obtain the driver's expected path, or alternatively the torque can be converted into a target yaw and / or lateral vehicle state, as for the first YSC system 10. The sensor device 21 also includes a sensor for sensing the vehicle's yaw rate and / or a sensor for sensing the vehicle's lateral acceleration or other vehicle lateral states (e.g. yaw rate based on wheel speed). In some embodiments, two inputs are used to allow a rationality check between them.

[0127] The oversteering control function of the brake ECU 22 is configured to minimize the error between the target vehicle state and the actual vehicle state by using braking torque, and is configured to control the braking system 24 and provide a request to it, which will actuate the request through the brake actuator so as to minimize the vehicle state error by controlling the longitudinal force on the tire of the wheel 9.

[0128] As mentioned above, the first and / or second YSC sensor arrangement 11 , 21 may also or additionally comprise a torsion bar torque sensor for determining a desired or target yaw and / or lateral vehicle state, although this is not necessary for controlling yaw stability.

[0129] It should be clear that the sensor arrangement may also include other additional sensors or use a sensor combination, or any other sensor, from which the vehicle speed, yaw rate and wheel angles, such as yaw, wheel speed (for each wheel) can be obtained by calculation.

[0130] In certain embodiments, additional redundancy may be provided by the first and second YSC systems 10, 20 monitoring each other, for example by sending sensor signals between the first and second YSC systems 10, 20, and / or by exchanging information about the target lateral vehicle state between the first and second YSC systems 10, 20. In addition to the brake actuator, additional actuators may be used to implement redundant control, such as one or more of a front axle steering actuator (for conventional steering), front and rear axle steering actuators, steer-by-wire actuators, angle superposition actuators, all-wheel drive clutch actuators (for controlling the distribution between front and rear axle drive in order to balance the vehicle yaw rate), torque vectoring (i.e., adding drive torque to individual wheels, which has an effect similar to braking individual wheels).

[0131] In an advantageous embodiment, the first YSC system 10 is fail-safe and in particular has an ASIL (Automotive Safety Integrity Level)-C level according to ISO 26262, and the second YSC system 20 is fail-safe and in particular has an ASIL-C level according to ISO 26262, and considering the lane departure hazard due to oversteering from the perspective of ISO 26262, the risk calculation adopts the following steps to achieve the Automotive Safety Integrity Level:

[0132] Risk management recognizes that consideration of the severity of a possible injury is modified by the likelihood of the injury occurring; that is, for a given hazard, if the likelihood of a hazardous event occurring is low, then the risk is considered low. The likelihood of an injury hazard is further classified based on a combination of exposure (E) (the relative expected frequency of operating conditions under which an injury could occur) and control (C) (the relative likelihood that the operator will be able to take action to prevent the injury).

[0133] - Severity classification S: Failure to keep lane is classified as S3 (life-threatening (survival uncertain) to fatal injury) due to the potential for fatal consequences.

[0134] - Controllability Classification C: Controllability for oversteer is C3 as it may be difficult or even impossible to control.

[0135] -Exposure category E: for wet road conditions with a risk frequency of E3, or medium probability, which the standard describes as occurring more than once a month, leading to Safety Integrity Level ASIL C, which is a measure of the effort required to ensure the YSC remains operational.

[0136] Thus, in this embodiment, the ASIL allocation in the safety critical system (decomposition of the fail-operable ASIL C requirement) is achieved by using two independent fail-safe systems YSC 10, 20 in parallel; one fail-operable system is allocated to both fail-safe systems. In order for a system to be fail-safe, it should be possible to shut down safely, but errors that could lead to dangerous behavior, here ASIL C level, must be detected and lead to shutting down the wrong function / system.

[0137] Fail-operability can also be achieved through redundancy, where three parts, functions, systems, sub-functions or subsystems are used in such a way that if one part differs from the other two by more than a certain value, then the two valid parts are used - "two out of three".

[0138] Sensor fusion is applied and will be referenced below Figure 3 , 4 Further discussion.

[0139] Figure 2is a schematic block diagram of a second embodiment of a vehicle motion control system having a fail-operable YSC function 100A. The YSC function 100A comprises a first YSC system 10A and a second YSC system 20A, which can be said to be partially independent, as will be further described below.

[0140] The first and second YSC systems 10A, 20A are interdependent to some extent, they are connected to a common sensor device 121, but both are fail-safe, allowing for failures, but are set to shut down if a failure is detected; when one is shut down, the other will still work while maintaining adequate safety. Figure 1 In the discussed embodiments, when only one system / function is used, a degraded mode may be provided, for example, such as providing a warning to the driver, reducing the speed or any other appropriate measure.

[0141] As reference Figure 1 In the illustrated embodiment, the first YSC system 10A is arranged to control yaw stability by controlling steering, while the second YSC system 20A is arranged to control yaw stability by controlling braking.

[0142] The first YSC system 10A comprises a steering control function, which comprises a steering ECU 12A having an oversteer control function 13A and comprises or is connected to a common sensor device 121 comprising a plurality of sensors for directly measuring or allowing calculation of at least vehicle speed, yaw rate and wheel angle.

[0143] The sensor device 121 particularly includes a driver input sensor for sensing the steering wheel angle or any other angle related to the steering wheel or wheel in the steering system, or a torsion bar torque sensor. The driver's expected path can be calculated according to the method in EP2440442, that is, the angle can be used together with the vehicle model to obtain the driver's expected path, or alternatively the torque can be converted into a target yaw and / or lateral vehicle state. The sensor device 121 also includes a sensor for sensing the vehicle's yaw rate and / or a sensor for sensing the vehicle's lateral acceleration or other vehicle lateral states (e.g., yaw rate based on wheel speed). In some embodiments, two inputs are used to allow a rationality check between them.

[0144] The steering ECU 12A oversteering control function is configured to minimize the error between the target and actual vehicle states by using the steering mechanism assist torque or, in the case of steer-by-wire, the steering position, and is configured to control the steering mechanism 14A and provide a request thereto, which the steering mechanism 14A will actuate by means of the steering system to minimize the vehicle state error by controlling the lateral force on the tire of the wheel 9A angle so that the vehicle assumes the desired direction.

[0145] The second YSC system 20A comprises a steering control function, which comprises a brake ECU 22A with an oversteering control function 23A and here comprises or is also connected to a common sensor device 121 which is thus common to the first and second steering control functions.

[0146] As reference Figure 1 As in the embodiment discussed, the oversteering control function of the brake ECU 22A is arranged to minimize the error between the target vehicle state and the actual vehicle state by using braking torque, and is arranged to control the steering mechanism 14A and provide a request to it, which the steering mechanism 14A will actuate with the aid of a brake actuator to minimize the vehicle state error by controlling the longitudinal force on the tire of the wheel 9A.

[0147] As mentioned above, the common YSC sensor arrangement 121 may also or additionally include a torsion bar torque sensor for determining a desired or target yaw and / or lateral vehicle state, although this is not necessary for controlling yaw stability.

[0148] It should be clear that the sensor arrangement may also include other additional sensors or use sensor combinations, or any other sensors from which the vehicle speed, yaw rate and wheel angles, such as yaw, wheel speed (for each wheel) can be derived by calculation.

[0149] However, in one embodiment, in order for the first and second YSCs to be fail-safe, the key sensors of the shared sensor device 121 need to be fail-operable, for example arranged in an architecture designed to tolerate safe and dangerous failures, such as a three-out-of-two (2oo3) architecture, where two of the three units are required for the system to operate and provide both safety and high availability. The two outputs from the three sensor units are wired or evaluated in a so-called voting circuit or algorithm, determining the actual output that forms the majority output. That is, a three-out-of-two logic mode is provided here, with three key sensors of the same type, two of which need to provide the same output. Sensor fusion will be referred to below Figure 3 , 5 Further discussion.

[0150] Another common sensor device 121 configuration is to use four sensors to directly or indirectly measure the information of interest and use two paired sensors to monitor each other within the sensor pair. Thus, schematically, there are two fail-safe pairs that form a fail-operable function, which is another mode of fail-operable function, as known to those skilled in the art.

[0151] The arrangement in the sensor arrangement 121 may be any mixture of a two-out-of-three mode and two fail-safe pairs. For example, the vehicle speed may be obtained by schematically arranging the four wheel speeds into two pairs of mutually monitored wheel speeds and thus forming two fail-safe sections, which would result in a fail-operable vehicle speed as previously described. The yaw rate may use a vote between the two yaw rate sensor values ​​and a virtual yaw rate value calculated from the wheel speeds.

[0152] In certain embodiments, additional redundancy may be provided by the first and second YSC systems 10A, 20A monitoring each other, for example by sending sensor signals between the first and second YSC systems 10A, 20A, and / or by exchanging information about the target lateral vehicle state between the first and second YSC systems 10A, 20A. In addition to the brake actuator, additional actuators may be used to implement redundant control, such as one or more of a front axle steering actuator (for conventional steering), front and rear axle steering actuators, steer-by-wire or angle superposition actuators, all-wheel drive clutch actuators (for controlling the distribution between the front and rear axle drive to balance the vehicle yaw rate), torque vectoring (i.e., adding drive torque to individual wheels, which has an effect similar to braking individual wheels).

[0153] In an advantageous embodiment, both the first and second YSC systems 10A, 20A are fail-safe, allowing for faults but being set to shut down if a fault is detected, in particular with ASIL (Automotive Safety Integrity Level)-C according to ISO 26262, so that if one of them shuts down, the other will still operate.

[0154] Alternatively, a two-out-of-three mode is used for the system, i.e. three independent systems / functions, and the results of the systems / functions are monitored, and if one of them shows a different result above a given threshold, that subsystem / function is shut down. Since only one of the three is shut down, the other two will work and even have the ability to detect further failures. There may also be reasons for degradation here.

[0155] The use of the degraded state is considered to be within the normal working range of those skilled in the art, and therefore, a more in-depth description thereof is beyond the scope of this specification.

[0156] These two strategies can also be mixed for different subsystems / functions. This will be shown in the examples.

[0157] Figure 3 is a general control scheme showing the general control of lateral vehicle conditions. Figure 3In the vehicle model 50, a target lateral vehicle state (e.g., vehicle yaw rate) is calculated from wheel angles and vehicle speed using a bicycle vehicle model, for example as described in WO2010 / 144049. The wheel angles may be calculated from any angle in the steering system. The vehicle 60 speed may be calculated from the wheel speeds.

[0158] The target lateral vehicle state obtained from the vehicle model 50 is compared with the sensed value obtained by the signal from the sensor 110, which is fused in the sensor fusion device 11X0, generating a control error. In the controller 120, the control error is minimized by controlling one or several actuators that have an effect on the lateral vehicle state to be controlled (the controller can be of various types, as should be known to those skilled in the art).

[0159] The target value of the driver's intended path or the yaw and / or lateral vehicle state, ie the target yaw and / or lateral vehicle state, can be calculated in two main ways: a steering angle-based target value or a steering torque-based target value.

[0160] When the vehicle is operated under conditions where the tire slip angle is below the limit, the relationship between the yaw rate and the steering angle is essentially linear; the quasi-static yaw rate is the product of the steering angle and the yaw gain for the linear bicycle model. In addition, the yaw rate is given by the lateral acceleration divided by the vehicle speed. More generally, a linear or nonlinear, quasi-static or dynamic bicycle model (bicycle model) can be used to set the ideal yaw and / or lateral vehicle state for a given condition based on the steering angle and the vehicle speed.

[0161] Target yaw and / or lateral vehicle state based on steering angle:

[0162] Here, the bicycle model is used as a dynamic function between vehicle speed and steering angle, giving a target yaw and / or lateral vehicle state, ie, the yaw and / or lateral vehicle state under ideal road conditions.

[0163] Target yaw and / or lateral vehicle state based on steering torque (see further EP2440442):

[0164] Here, the steering torque is first calculated based on the steering wheel torque. Then, since there is a relationship between the steering torque and the yaw and / or lateral vehicle state fed back by the steering torque (for example, the steering torque is a function of the vehicle's lateral acceleration state), the relationship can be inverted. This inverted relationship can be used to calculate the target yaw and / or lateral vehicle state based on the steering torque.

[0165] The actual yaw and / or lateral vehicle state corresponding to the target yaw and / or lateral vehicle state is measured using sensors and refined and checked in sensor fusion. In case the slip angle is the state to be controlled, the slip angle is calculated from the yaw rate and the lateral acceleration in a manner known to those skilled in the art.

[0166] Figure 4 The present invention corresponds to the reference Figure 1 A control scheme of one implementation of the described embodiment. There is a common vehicle state controller 12 for the front wheel steering 14 and a common vehicle state controller 23 for the wheel brakes or brake system 24, using respective input control errors obtained by comparing target values ​​from the respective vehicle model 5, 5' and sensor values ​​from the respective sensor fusion 11X, 11X'. The sensor devices 11, 21 need to be redundant so that faults can be detected. Either by using two sensors so that if they show different values ​​exceeding a threshold, there is a fault and the function is switched off. Or alternatively, one sensor is used and a plausibility check is performed by using some other sensor. An example is to use one yaw rate sensor for the lateral vehicle state and to check the plausibility of the sensed yaw rate by using two wheel speeds on the same axle and from them the yaw rate is calculated as the speed difference divided by the wheelbase.

[0167] Figure 5 The present invention corresponds to the reference Figure 2 A control scheme of an implementation of the described embodiment. Figure 2 In the embodiment shown, by Figure 5 In the control scheme, there is also a controller 13A for the front wheel steering 14A and a controller 23A for the wheel brake or brake system 24A, using corresponding input control errors obtained by comparing the target values ​​from the corresponding vehicle model 5A, 5A' and the sensor values ​​from the corresponding sensor fusion 11AX, 11AX' based on the input values ​​from the common sensor device 121. Here, the key sensors of the sensor device need to be fail-operable. One way to achieve fail-operable behavior is to make the information redundant, with at least a three-choose-two "mode". The following will refer to Figure 6 An example of sensor fusion for such an embodiment is further described.

[0168] Figure 6 Exemplary embodiments of a fail-operable sensor arrangement are disclosed, and exemplary sensor fusion is shown in detail, for example, for reference Figure 2 and Figure 5The described embodiment uses a controller 12B and a vehicle model 5B for actuators 16B such as a steering mechanism or a brake actuator. A common sensor setup is used here. Only one controller is shown here, but for a complete understanding of the embodiment, there is a set of parallel controllers and possibly also vehicle models, all using the same sensors and possibly also sensor fusion.

[0169] As an example, for the wheel angle sensor fusion function 111BX, the wheel angle is calculated based on the steering wheel angle obtained from the steering wheel angle sensor 11B1 multiplied by the ratio between the steering wheel and the wheel. In addition, two motor angle sensors 11B2 (in the auxiliary motor) are used here to multiply the ratio between the auxiliary motor and the wheel, thus providing a total of three calculated wheel angles. Using the three wheel angles calculated in this way, a "three-out-of-two" pattern is used in sensor fusion to provide a "voted" fail-operable wheel angle for the vehicle model 5B. If the voting scheme detects that a value is out of range, degradation can be performed as described previously.

[0170] A wheel speed sensor fusion function 112BX is used, where the wheel speeds are processed in a similar manner as described above for wheel angle sensor fusion, but here the wheel speeds are four (four wheels), and the vehicle speed can use a "two out of three" approach for multiple sets of wheel speed sensors 11B3. The "voted" fault actionable vehicle speed, i.e., the vehicle speed transmitted to the vehicle model 5B, is the output of the wheel speed sensor fusion 112BX.

[0171] The yaw rate sensor fusion function 113BX here uses two yaw rate sensors 11B4 and a yaw rate calculated from the wheel speed sensor 11B3 and a "three out of two" mode to provide a fail-operable yaw rate signal as output to the vehicle model 5B.

[0172] Figure 7 is a control scheme that discloses an exemplary implementation of a fail-operable sensor arrangement and shows in detail an exemplary sensor fusion, for example, for reference Figure 2 and 5 The described embodiment uses a controller 12C and a vehicle model 5C for an actuator 16C such as a steering mechanism or a brake actuator. Figure 7 Only one controller is shown, but for a full understanding of the embodiment, there is a set of parallel controllers and possibly a vehicle model, all using the same sensors and possibly sensor fusion. Figure 7 The embodiment shown in the figure discloses an exemplary method for calculating the target yaw rate according to one embodiment of the present invention, which is also based on using a reference Figure 2 and5 A common sensor arrangement is described.

[0173] In such as through Figure 7 In the embodiment schematically shown in FIG. 1 , the target yaw rate 18C is calculated slightly differently than in other embodiments. Here, the steering wheel torque (typically sensed by two torsion bar torque sensors to achieve a fail-safe state) is used as an indication of the driver's intended lateral vehicle state. The target lateral vehicle state is calculated from the steering wheel angle or from the wheel angle, steering wheel torque and vehicle speed using a steering wheel torque sensor 11C1, a steering wheel angle sensor 11C2, two motor angle sensor arrangements 11C3, a wheel speed sensor 11C4 and two yaw rate sensor arrangements 11C5.

[0174] For the sensor fusion in the sensor fusion function (wheel angle sensor function 111CX, wheel speed sensor fusion 112CX and yaw rate function 113CX), as illustrated above using "three out of two", only one sensor fusion is required to enable that particular signal to control both the brakes and steering in a fail-operable manner.

[0175] For sensor fusion with only two sensors (such as steering wheel torque), only fail-safe can be achieved. This means that in order to be able to use a common sensor setup, the torsion bar torque sensor (used to sense steering wheel torque) needs to be fail-operable, such as three sensors and a "two out of three" voting scheme.

[0176] If the steering wheel torque is used only for steering control, two sensors will be sufficient as each control path will be fail-safe, forming two independent fail-safe controllers which together are fail-operable.

[0177] According to the inventive concept, and also as described or illustrated above, a division between two fail-safe functions or systems and one fail-operable function or system can be provided anywhere and at any level in the YSC functional control scheme, and all combinations of two fail-safe systems (or arrangements) or functions and three-out-of-two systems (or arrangements) or functions are possible.

[0178] In particular, the inventive concept covers any combination of independent fail-safe systems or functions and / or fail-operable subsystems or fail-operable functions, such as input signal sensing, sensor fusion functions, target yaw and / or lateral vehicle state calculation, control, actuation, to provide a fail-operable YSC functionality.

[0179] It is also clear from the above description of the figures that the YSC function needs to be fail-operable. In addition, it can be made fail-operable by using two independent fail-safe functions, where the sensors can be independent or shared, but in the case of shared sensors, the input sensing needs to be fail-operable.

[0180] In summary, the knowledge gained so far leads to two "modes" of used fail-operable functions, namely "two out of three" and "two independent fail-safe". These two modes can be used for any and all combinations of sub-functions / subsystems and even parts of them. It has been demonstrated that the use of a common sensor assembly "two out of three" can be combined with a "two independent fail-safe" function / system for the remaining parts. Any combination of these two modes can be used for the following functions, also referred to here as sub-functions:

[0181] Input signal sensing,

[0182] Sensor fusion,

[0183] Target calculation,

[0184] Control, and

[0185] Actuation,

[0186] As well as subsystems. It can even be used differently between different input signals such as vehicle speed, yaw rate and steering angle. Since the pattern is generic, it can be used differently in any sub-function / subsystem structure at any granularity.

[0187] In some cases, redundancy is not required, for example when a component has been proven in practice to have a sufficiently low failure rate compared to the required safety-related failure rate, or is duplicated in practice. Such components are often mechanical, such as steering columns, etc., and such sub-functions and / or sub-systems can also be used as part of redundant functions / systems.

[0188] A special case of a "two independent fail-safe" subfunction or subsystem is when two independent components are built together. An example of such a subsystem is a six-phase motor, which can be viewed as two three-phase motors built together, where the magnets can be viewed as mechanical elements proven in practice.

[0189] In the above example, independent fail-safe systems are used, one of which is a steering system (of any type mentioned in the definition) and a braking system. The other system used to control the longitudinal forces on the wheels is torque vectoring. Therefore, for one of the independent fail-safe systems, torque vectoring can be used instead of braking, thus demonstrating a fail-operable YSC functionality.

[0190] Furthermore, according to the invention, since the YSC function must be fail-operable, any combination of independent fail-safe systems may be used:

[0191] Steering system and braking system (as described in the figure),

[0192] Steering system and torque vectoring control system,

[0193] Braking system and torque vectoring control system.

[0194] Furthermore, according to the present invention, since the YSC function must be fail-operable, any single fail-operable system may be used, such as:

[0195] Fail-operable steering system,

[0196] Failure to operate the brake system, and

[0197] Fail-operable torque vectoring control system.

[0198] The steering position control function for steer-by-wire or automated driving is fail-operable (because there is no torque from the driver in the path from the steering wheel (if any) to the wheels, so there is no fallback) and can be used in conjunction with the fail-operable YSC function. The same reasoning applies to the braking system and torque vectoring control system.

[0199] Figure 6 and 7 The control diagram shown in FIG. 1 can be used for at least two fail-safe systems (such as reference Figure 1 and 2 The described) implementation may also be implemented for a fail-operable subsystem, in which case no additional controller, or two branches, is required.

[0200] According to the present invention, the YSC functionality as a whole (implemented by software, systems and system components, functions or subsystems) is redundant, and the redundant YSC functionality is provided by steering and two or more steering system actuators (redundancy is achieved by duplicating or tripling those parts of the steering that are not proven in practice as described above), or one (or more) steering system actuators and a braking actuator, and / or a steering system actuator and a torque vectoring control actuator, or a braking actuator and a torque vectoring control actuator, or any other actuator combination.

[0201] One advantage is that according to the invention, by means of a fail-operable YSC function, i.e. in its entirety, the overall YSC function, the vehicle can be made to understeer less, since the vehicle stability is made fail-operable safe. A vehicle with less understeer will have an improved cornering ability and will therefore be safer.

[0202] Another advantage is that the YSC functionality may be made fail-operable by controlling one or more selected yaw and / or lateral vehicle conditions.

[0203] Yet another advantage is that the fail-operable YSC function allows an inexperienced driver to steer the vehicle in a safe manner even on wet and slippery roads without losing control.

[0204] Another advantage is that it allows the vehicle to be driven autonomously in a safe manner, with the driver removed and therefore unable to act as the primary driver, while using the YSC as redundancy.

[0205] A further advantage is that rear axle regeneration can be used in a safe manner since the potential risk of instability is handled redundantly.

[0206] It should be clear that the inventive concept also covers embodiments having a steering device comprising, for example, a yoke-type joystick or any other input device instead of a steering wheel, and that the inventive concept is applicable to conventional steering systems for road vehicles comprising a mechanical connection between the steering wheel and the steering wheel, as well as other steering systems without a mechanical connection, generally referred to as SbW (steer-by-wire) systems.

[0207] It is clear that the invention is not limited to the specifically described embodiments but can be varied in many ways within the scope of the appended claims and that features of different embodiments can be combined. In particular, it is clear that the path intended by the driver or the target value for the yaw and / or lateral vehicle state (target yaw and / or lateral vehicle state) can be calculated based on the steering angle or based on the steering torque, as described with reference to Figure 1 The same also applies to any other embodiments described or falling within the scope of the claims.

Claims

1. A vehicle motion control system (100; 100A) having a steering system (14, 14A) and / or a braking system (24; 24A) and / or a torque vectoring control system, and a plurality of sensor devices, the sensor devices comprising sensors (11, 21; 11A; 21A; 121; 11B1-11B4; 11C1-11C5) for directly sensing and / or allowing calculation of at least vehicle speed or wheel speed, yaw rate and steering angle, the vehicle motion control system (100; 100A) comprising a yaw stability control (YSC) function with an oversteer control function, Features The YSC function is arranged to be fail-operable and comprises at least two YSC systems (10, 20; 10A, 20A) so that when one system is shut down, the other system will still operate, each system being connected to one or more of the sensor devices, the sensor devices comprising a plurality of sensors (11, 21; 121; 11B1-11B 4； 11C1-11C5), the at least two YSC systems (10, 20; 10A, 20A) each comprising a controller (12, 22; 12A, 22A; 12B; 12C), the controller comprising an oversteer control function (13, 23; 13A, 23A) for controlling the vehicle path by controlling the yaw and / or lateral vehicle state, the at least two YSC systems (10, 20; 10A, 20A) comprising at least two of the following in any combination: One or more YSC systems (10; 10A) arranged to act on a vehicle's steering system (14; 14A) by acting on one or more steering system actuators, the steering system actuators comprising steering system mechanisms or position actuators; a YSC system (20; 20A) arranged to act on a vehicle's braking system (24; 24A) by acting on one or more braking system actuators; and a YSC system arranged to act on a vehicle's torque vectoring control system by acting on one or more torque vectoring control system actuators.

2. The vehicle motion control system (100; 100A) according to claim 1, characterized in that The sensor arrangement (11, 21; 121) comprises at least sensors for collecting information allowing the vehicle speed, the steering angle and at least one yaw and / or lateral vehicle state to be determined by direct sensing or by calculation.

3. The vehicle motion control system (100; 100A) according to claim 2, characterized in that The sensor arrangement (11, 21; 121) also comprises at least one sensor collecting information allowing the driver or torsion bar torque to be determined.

4. The vehicle motion control system (100; 100A) according to claim 2 or 3, characterized in that The or each sensor device (11, 21; 11A, 21A) comprises at least one or more sensors for allowing one or more target yaw and / or lateral vehicle states to be calculated by a vehicle model using one or more of steering angle, vehicle speed, or using steering angle, torsion bar torque and counter-steering torque feedback calculation, the steering torque being a feedback or function of the yaw and / or lateral vehicle state, and sensing or calculating an actual yaw and / or lateral vehicle state, such as vehicle yaw rate, vehicle lateral acceleration or vehicle slip, and wherein a difference between a target state and an actual state is set or calculated, forming at least one control error, and wherein the control error is input to each controller (12, 22; 12A, 22A; 12B; 12C).

5. A vehicle motion control system (100; 100A) according to any one of the preceding claims, characterised in that The at least two YSC systems include a first YSC system (10; 10A), which has a controller (12; 12A) including a steering control function, the controller including an ECU for steering control having an oversteering control function (13; 13A), and is arranged to act on a vehicle steering system (14; 14A) by acting on one or more steering system actuators, the steering system actuator including a steering system mechanism or a position actuator; and a second YSC system (20; 20A), which has a controller including a braking control function (22; 22A), the controller including an ECU with an oversteering control function (23; 23A), and is arranged to act on a vehicle braking system (24; 24A) by acting on one or more braking system actuators.

6. A vehicle motion control system (100; 100A) according to at least claim 5, characterized in that The steering control function (12; 12A; 12B; 12C) comprises an oversteer control function (13; 13A) of at least one of the two YSC systems (10; 10A), which is arranged to control the steering angle by controlling the steering system actuator, thereby generating lateral forces on the vehicle wheel tires to minimize the error between the target yaw and / or lateral vehicle state and the actual yaw and / or lateral vehicle state.

7. A vehicle motion control system (100; 100A) according to at least claim 4 or 5, characterized in that The braking control function (22; 22A; 22B; 22C) comprises an oversteer control function (23; 23A) of one of at least two YSC systems (20; 20A), which is arranged to control the longitudinal forces on the vehicle wheel tires by controlling braking or torque vectoring control actuators to minimize the error between the target yaw and / or lateral vehicle state and the actual yaw and / or lateral vehicle state.

8. A vehicle motion control system (100; 100A) as claimed in any one of the preceding claims, characterised in that The at least one yaw and / or lateral vehicle state comprises at least one or more of vehicle wheel velocity, vehicle angular velocity about an axis in yaw, pitch or roll direction, acceleration in longitudinal, lateral or vertical direction, vehicle position, slip angle, lateral acceleration or a linear combination thereof.

9. A vehicle motion control system (100; 100A) according to claim 4 or any one of claims 5-8 when dependent on claim 4, characterised in that The control error or each control error is used as an input to a steering control function (12; 12A) and / or a braking control function (22; 22A) and / or a torque vectoring control function, and wherein the steering control function (12; 12A) and / or the braking control function (22; 22A) and / or the torque vectoring control function is adapted to minimize the input control error by controlling one or more steering actuators and / or braking actuators and / or torque vectoring control actuators, respectively.

10. A vehicle motion control system (100) according to any one of the preceding claims, characterised in that The at least two YSC systems (10, 20) are independent.

11. The vehicle motion control system (100) according to claim 10, characterized in that The at least two YSC systems (10, 20) are fail-safe.

12. The vehicle motion control system (100) according to claim 11, characterized in that At least two YSC systems (10, 20) are fail-safe meeting ASIL-C requirements.

13. The vehicle motion control system (100) according to any one of claims 1 to 10, characterized in that It comprises two sensor devices (11, 21), namely a first sensor device (11) for a first YSC system (10) and a second sensor device (21) for a second YSC system (20), and wherein for each of said sensor devices (11, 21), key sensors for determining at least vehicle speed, steering angle and at least one yaw and / or lateral vehicle state are redundant, thereby allowing detection of faults, and wherein if a fault of a key sensor of the first or second sensor device (11, 21) is detected, the YSC function of the corresponding YSC system (10, 20) is shut down, for example also including providing a warning or indication to the vehicle driver.

14. The vehicle motion control system (100A) according to any one of claims 1 to 9, characterized in that It comprises a sensor device (121) which is common to the first YSC system (10A) and the second YSC system (20A) and in which key sensors for determining at least vehicle speed, steering angle and at least one yaw and / or lateral vehicle state are at least triple redundant according to a two-out-of-three logic.

15. The vehicle motion control system (100A) according to claim 14, characterized in that The common sensor device (121) is configured or arranged to be fail-operable.

16. The vehicle motion control system (100A) according to claim 15, characterized in that The sensor device (121) includes: a steering wheel angle sensor (11B1) and two motor angle sensors (11B2, 11B2) allowing calculation of three wheel angles; and a wheel angle sensor fusion function (111BX) implementing a three-choice two logic to provide wheel angle or steering angle signals to the vehicle models of the first and second YSC systems (10A, 20A), Wheel speed sensors (11B3) for sensing four wheel speeds, and a wheel speed sensor fusion function (112BX) implementing a two-out-of-three logic to provide vehicle speed signals to the vehicle models of the first and second YSC systems (10A, 20A), and Two yaw rate sensors (11B4, 11B4) are used to provide two yaw rate signals to a yaw rate sensor fusion function (113BX), and the yaw rate sensor fusion function (113BX) is also arranged to calculate a third yaw rate based on the wheel speed signal from the wheel speed sensor (11B3), thereby realizing a three-out-of-two logic to provide yaw rate signals to the control errors of the controllers (12B) of the first and second YSC systems (10A, 20A).

17. The vehicle motion control system (100A) according to any one of claims 14 to 16, characterized in that The sensor arrangement comprises: three steering wheel torque sensors (11C1), one steering wheel angle sensor (11C2) and two motor angle sensors (11C3, 11C3), which provide signals to a steering angle sensor fusion function (111CX) which implements a three-out-of-two logic for calculating a target yaw and / or lateral vehicle state in a calculation function (18C), Wheel speed sensors (11C4) for sensing four wheel speeds, and a wheel speed sensor fusion function (112CX) implementing a three-out-of-two logic to provide a vehicle speed signal to a target yaw and / or lateral vehicle state calculation function (18C), and Two yaw rate sensors (11C5, 11C5) are used to provide two yaw rate signals to a yaw rate sensor fusion function (113CX), and the yaw rate sensor fusion function (113CX) is also arranged to calculate a third yaw rate based on the wheel speed signal from the wheel speed sensor (11C4), thereby realizing a three-out-of-two logic to provide an actual yaw and / or vehicle state signal to a control error calculation function, and the yaw and / or lateral vehicle state calculation function (18C) provides a target yaw and / or lateral vehicle state signal to the control error calculation, so as to input the calculated control error into the controller (12B) of the first and second YSC systems (10A, 20A).

18. The vehicle motion control system (100A) according to claim 1, characterized in that Fail-operable YSC functionality is provided by one or more fail-operable vehicle systems, or a combination of fail-safe and fail-operable subsystems or sub-functions.

19. The vehicle motion control system (100A) according to claim 18, characterized in that The one or more fail-operable systems are a fail-operable steering system and / or a fail-operable braking system and / or a fail-operable torque vectoring control system of the vehicle.

20. The vehicle motion control system (100A) according to claim 19, characterized in that The fail-operable steering system and / or fail-operable braking system and / or fail-operable torque vectoring control system is realized by a combination of independent fail-safe and fail-operable subsystems or sub-functions, such as including an input signal sensing device (121), a sensor fusion device, a target calculation, a control system, an actuation device, such as a steering system, a braking system or a torque vectoring control system with dual ECUs, a steering system with dual motors, a shared sensor, etc.

21. A vehicle motion control system (100; 100A) according to any one of the preceding claims, characterised in that It is suitable for use in steer-by-wire systems or wireless steering systems.

22. The vehicle motion control system (100; 100A) according to any one of claims 1 to 21, characterized in that It is suitable for use in autonomous vehicles with fail-operable steering systems.

23. A vehicle comprising a vehicle motion control system according to any one of claims 1 to 22, characterized in that It is a car, bus, truck, a self-driving car, bus, truck or similar vehicle, a hybrid vehicle or a fully electric vehicle.

24. A vehicle motion control method for a vehicle, the vehicle having A steering system (14, 14A) and / or a braking system (24; 24A) and / or a torque vectoring control system, and a plurality of sensor devices, including sensors (11, 21; 11A; 21A; 121; 11B1-11B4; 11C1-11C5) for directly sensing and / or allowing calculation of at least vehicle speed or wheel speed, yaw rate and steering angle, the vehicle motion control system (100; 100A) comprising a yaw stability control (YSC) function with an oversteer control function, characterized in that It includes the following steps: - Arrange the YSC function to be fail-operable by: - providing at least a first and a second YSC system, such that when one of them is switched off, the other will still be operational for controlling the vehicle path by controlling the yaw and / or lateral vehicle state, said at least first and second YSC systems being independent, each having a controller with an oversteer control function, and each connected to one or more sensor devices including a plurality of sensors, The at least two YSC systems (10, 10A; 20, 20A) further include at least two of the following in any combination: One or more YSC systems (10; 10A) arranged to act on a steering system (14; 14A) of a vehicle by acting on one or more steering system actuators, the steering system actuators comprising steering system mechanisms or position actuators, A YSC system (20; 20A) arranged to act on a braking system (24; 20A) of a vehicle by acting on one or more braking system actuators, A YSC system is arranged to act on the vehicle's torque vectoring control system by acting on one or more torque vectoring control system actuators.

25. The vehicle motion control method according to claim 24, characterized in that It includes steps to provide fail-operable YSC functionality by: - Providing at least a first and a second fail-safe YSC system.

26. The vehicle motion control method according to claim 24, characterized in that It includes steps to provide fail-operable YSC functionality by: -Providing one or more fail-operable vehicle systems, or a combination of fail-safe and fail-operable subsystems or sub-functions.

27. The vehicle motion control method according to any one of claims 24 to 26, characterized in that For yaw and / or lateral vehicle state control, it includes the following steps: - determining a measure of the torque applied by the driver through the steering wheel based on input signals from the sensor device, - converting the above-mentioned measured input signal of the torque applied by the driver via the steering wheel into a target yaw and / or lateral vehicle state, - providing target yaw and / or lateral vehicle states as input signals to one or more YSC controllers, - minimizing in the YSC controller a control error between a target yaw and / or lateral vehicle state and a corresponding measured actual yaw and / or lateral vehicle state, - controlling said one or more yaw and / or lateral vehicle state actuators so as to perform vehicle state control using said minimized control error.

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