Vehicle motion control system

Abstract

The present disclosure relates to coordinating and synchronizing a vehicle motion control system of a vehicle including a wheel individual brake system comprising first actuators for applying brake torque to individual wheels of the vehicle and a driveline torque vector actuator system comprising second actuators for applying torque to individual wheels of the vehicle by a propulsion system, comprising: a central control function module comprising a plurality of yaw torque controllers each configured to receive data comprising driver input and vehicle motion state to determine a respective yaw torque based on the received data. The central control function module is configured to determine a driving situation based on the received data; arbitrate a plurality of yaw torques from the individual yaw torque controllers to determine a single yaw torque based on the driving situation; coordinate execution of the yaw torque by the wheel individual brake system and the driveline torque vector actuator system; deliver the yaw torque request to the first actuators and / or the second actuators to execute the single yaw torque.

Description

Technical Field

[0001] This disclosure relates to vehicle motion control systems, vehicle motion control methods, vehicles including vehicle motion control systems, computer programs, and computer-readable data carriers. Background Technology

[0002] Understeer and oversteer describe the yaw attitude of a road vehicle when its yaw is less than or greater than the driver's intention. The behavior of understeer and oversteer vehicles is... Figure 1 As shown in the diagram. When a vehicle does not accurately follow the driver's intentions, it can lead to an unpleasant driving experience and, in more serious cases, cause the driver to lose control of the vehicle. ESC (Electronic Stability Control) systems have traditionally been used to control a vehicle's yaw behavior by applying friction braking torque to individual wheels. The introduction of powertrain actuators (such as eLSD (electronic limited-slip differential), TVDC (torque vectoring dual clutch), electric motors for individual wheels, etc.) has increased the possibility of influencing vehicle yaw behavior by controlling the torque of individual wheels (also known as torque vectoring actuators) and has been used in a wide variety of vehicle handling applications.

[0003] Traditionally, different control algorithms have been used to control torque vectoring and ESC systems. In some cases, depending on the vehicle model used in the control algorithm, one system may compete with another rather than complement it, leading to inefficient control actions. Summary of the Invention

[0004] Therefore, there may be a need to improve vehicle yaw motion control.

[0005] The objective is to be addressed or mitigated, at least in part, by the independent claims disclosed in this disclosure, wherein further examples are incorporated into the dependent claims.

[0006] According to a first aspect, a vehicle motion control system is provided for coordinating and synchronizing wheel-specific braking systems and power transmission torque vectoring actuator systems in a vehicle. The wheel-specific braking system includes at least one first actuator for applying braking torque to individual wheels of the vehicle, and the power transmission torque vectoring actuator system includes at least one second actuator for applying torque to individual wheels of the vehicle via a propulsion system. The vehicle motion control system includes a central control function module comprising a plurality of yaw torque controllers. Each yaw torque controller is configured to receive data including driver input and vehicle motion state to determine a respective yaw torque based on the received data for controlling the yaw behavior of the vehicle. The central control function module is configured to determine driving conditions based on the received data. The central control function is also configured to adjudicate the plurality of yaw torques from the individual yaw torque controllers to determine a single yaw torque based on the driving conditions. The central control function is further configured to determine a priority order of at least one first actuator and at least one second actuator depending on the driving conditions and expected vehicle attributes describing desired characteristics of the vehicle. The central control function is also configured to coordinate the execution of yaw torque by the individual braking systems of the wheels and the powertrain torque vectoring actuator system to deliver yaw torque requests to at least one first actuator and at least one second actuator according to a determined priority in order to execute a single yaw torque.

[0007] The vehicle motion control system described in this paper can coordinate and synchronize several different actuators in the individual wheel braking systems and powertrain torque vectoring actuator systems to achieve vehicle-level corrected yaw torque. Accordingly, the vehicle motion control system can mitigate understeer and oversteer behavior and provide a flexible and safe driving experience.

[0008] The at least one first actuator may include a service braking system, which refers to a primary system for braking, such as, but not limited to, an electro-hydraulic braking system, an electromechanical braking system, or any combination thereof.

[0009] Examples of the at least one second actuator may include, but are not limited to, wheel-specific electric motors, torque vectoring dual clutches, torque vectoring differentials, electronic limited-slip differentials, or any combination thereof.

[0010] Different adjudication strategies can be used, which provides expected properties in terms of flexibility and stability. Based on the adjudicated yaw torque, and taking into account various types of limitations and feedback from the yaw torque applied by the actuator, a suitable actuator can be selected to apply the yaw torque. This will be explained in detail below, particularly regarding... Figure 4 As shown in the example.

[0011] Considering the desired vehicle attributes (which describe the desired characteristics of the vehicle), a suitable actuator can be selected to apply yaw torque. The desired vehicle attributes can be set at the factory and can be driver-configurable. For example, a user can select the desired vehicle attributes via a user interface, and the vehicle can automatically coordinate the execution of yaw torque by the wheel-specific braking system and the powertrain torque vectoring actuator system to deliver the yaw torque request to the appropriate actuator to apply the yaw torque, thereby achieving the desired vehicle attributes. For example, in a vehicle with wheel-specific friction braking systems controlled by ESC and a powertrain torque vectoring system similar to dual electric motors, the user can select "Comfort" as the desired vehicle attribute. In this case, when driving significantly below the grip limit, the dual electric motor system can take precedence over the ESC system because it is generally quieter, more fuel-efficient, and avoids the pump and valve noise generated by the ESC actuator. This can provide a superior driving experience without compromising agility and safety. This will be explained in detail below, particularly regarding... Figure 4 As shown in the example.

[0012] As an example, anticipated vehicle attributes may include energy efficiency, driving experience, safety, noise, vibration, or any combination thereof.

[0013] According to one example, the central control function module can be configured to: receive data indicating the yaw torque capability of each actuator; determine at least one actuator for performing the requested yaw torque based on the yaw torque capability; reallocate the yaw torque request between at least one first actuator and at least one second actuator when necessary; and deliver the yaw torque request to at least one determined actuator.

[0014] Actuator yaw torque capacity can be used as a limit to request yaw torque from a particular actuator to avoid over-utilizing any actuator.

[0015] According to one example, the central control function module can be configured to: receive data indicating the tire longitudinal force generation capability of each tire of the vehicle; determine at least one actuator for performing the requested yaw torque based on the tire longitudinal force generation capability; reallocate the yaw torque request between at least one first actuator and at least one second actuator when necessary; and deliver the yaw torque request to at least one determined actuator.

[0016] Yaw torque capacity can be used as a limit on the yaw torque requested for a particular tire to avoid overutilizing any tire when another tire with a higher capacity to generate longitudinal force can be used.

[0017] According to one example, the central control function module can be configured to: receive feedback on the amount of yaw torque that has been executed; and based on the feedback, determine one or more additional actuators for executing the requested yaw torque (if it is determined that the execution of the requested yaw torque is insufficient or excessive).

[0018] In this way, an accurate amount of yaw torque can be applied by using several complementary actuators.

[0019] According to one example, the central control function module can be configured to: receive feedback on the longitudinal slip of individual wheels; and control the maximum yaw torque requested from at least one first actuator and / or at least one second actuator based on the feedback on the longitudinal slip of individual wheels.

[0020] By controlling the maximum torque requested from the actuator through feedback control based on the longitudinal slip of individual wheels, the wheel slip can be limited.

[0021] As an example, multiple yaw torque controllers may include feedforward controllers, feedback controllers, or any combination thereof.

[0022] According to one example, multiple yaw torques may include feedforward yaw torque, feedback understeering yaw torque, feedback oversteering yaw torque, or any combination thereof.

[0023] According to a second aspect of this disclosure, a vehicle is provided. The vehicle includes a wheel-individual braking system and a power transmission torque vectoring actuator system. The wheel-individual braking system includes at least one first actuator for applying braking torque to individual wheels of the vehicle, and the power transmission torque vectoring actuator system includes at least one second actuator for applying torque to individual wheels of the vehicle via a propulsion system. The vehicle also includes a vehicle motion control system of the first aspect and any associated examples, configured to coordinate and synchronize the wheel-individual braking system and the power transmission torque vectoring actuator system.

[0024] According to one example, at least one first actuator may include a service braking system capable of applying braking torque to individual wheels.

[0025] Examples of service braking systems may include, but are not limited to, electrohydraulic braking systems, electromechanical braking systems, or any combination thereof.

[0026] According to one example, at least one second actuator may include a power transmission torque vectoring system configured to apply propulsion torque or braking torque to an individual wheel.

[0027] Examples of power transmission torque vectoring systems may include, but are not limited to, wheel-specific electric motors, torque vectoring dual clutches, torque vectoring differentials, electronic limited-slip differentials, or any combination thereof.

[0028] According to one example, a vehicle may include a sensor system comprising one or more sensors for detecting the vehicle's motion state and driver input.

[0029] According to a third aspect of this disclosure, a vehicle motion control method is provided for coordinating and synchronizing wheel-specific braking systems and power transmission torque vectoring actuator systems in a vehicle. The wheel-specific braking system includes at least one first actuator for applying braking torque to individual wheels of the vehicle, and the power transmission torque vectoring actuator system includes at least one second actuator for applying torque to individual wheels of the vehicle via a propulsion system. The method includes the following steps:

[0030] - Data including driver input and vehicle motion status is received by each yaw torque controller in the central control module.

[0031] - Each yaw torque controller in the central control module determines its own yaw torque based on the received data, which is used to control the vehicle's yaw behavior.

[0032] - The central control module determines the driving situation based on the received data.

[0033] - The central control module adjudicates multiple yaw torques from individual yaw torque controllers to determine a single yaw torque based on driving conditions;

[0034] - Determine the priority order of at least one first actuator and at least one second actuator based on the driving conditions and the expected vehicle attributes describing the desired characteristics of the vehicle; and

[0035] - Coordinate the individual braking system of the wheel and the power transmission torque vectoring actuator system to execute yaw torque, and deliver yaw torque requests to at least one first actuator and at least one second actuator according to the determined priority in order to execute a single yaw torque.

[0036] This method can be implemented at least partially by a computer, and can be implemented in software or hardware, or both. Furthermore, the method can be implemented by computer program instructions running on a component that provides data processing functionality. The data processing component can be a suitable computing component (such as an electronic control module), or it can be a distributed computer system. The data processing component or the computer can each include one or more processors, memory, data interfaces, etc.

[0037] According to a fourth aspect of this disclosure, a computer program is provided, including instructions for inducing a vehicle motion control system of the first aspect or a vehicle of the second aspect to perform the steps of the method of the third aspect.

[0038] According to another aspect of this disclosure, a computer-readable data carrier having a computer program stored thereon is provided.

[0039] Controllers, such as central control function modules and yaw torque controllers, can be implemented in numerous ways (e.g., via dedicated hardware) to perform the various functions described herein. A “processor” is an example of a controller employing one or more microprocessors, which can be programmed using software (e.g., microcode) to perform the various functions discussed herein. Controllers can be implemented with or without a processor and can be implemented as a combination of dedicated hardware performing some functions and processors (e.g., one or more programmed microprocessors and associated circuitry) performing other functions. Examples of controller components that can be employed in various embodiments of this disclosure include, but are not limited to, conventional microprocessors, application-specific integrated circuits (ASICs), and field-programmable gate arrays (FPGAs). In various implementations, a processor or controller can be associated with one or more storage media (collectively referred to herein as “memory,” such as volatile and non-volatile computer memory). In some implementations, the storage medium can be encoded with one or more programs that, when executed on one or more processors and / or controllers, perform at least some of the functions discussed herein. Various storage media may be fixed within a processor or controller, or may be removable, such that one or more programs stored thereon may be loaded into the processor or controller to implement the various aspects of this disclosure discussed herein. The terms “program” or “computer program” are used herein in a general sense to refer to any type of computer code (e.g., software or microcode) that can be used to program one or more processors or controllers.

[0040] It should be noted that, regardless of the aspects involved, the above embodiments can be combined with each other. Accordingly, methods can be combined with structural features, and similarly, apparatuses and systems can be combined with the features described above regarding the method.

[0041] These and other aspects of this disclosure will become apparent and elucidated with reference to the embodiments described below. Attached Figure Description

[0042] Exemplary embodiments of this disclosure will now be described with reference to the accompanying drawings.

[0043] Figure 1 The behavior of vehicles exhibiting understeer and oversteer is shown.

[0044] Figure 2 A schematic top view of a vehicle with an exemplary TVDC is shown, which has left and right output levers connected to a propulsion actuator via a clutch.

[0045] Figure 3 A block diagram of an exemplary vehicle motion control system in a vehicle is shown.

[0046] Figure 4 A block diagram illustrates an overview of an exemplary yaw torque hybrid workflow.

[0047] Figure 5 The friction circle and force limit of the tire are shown.

[0048] Figure 6 The standardized longitudinal tire force characteristics are shown.

[0049] Figure 7 A flowchart of an exemplary yaw motion control method is shown.

[0050] The accompanying drawings are merely illustrative and are used only to illustrate embodiments of this disclosure. In principle, identical or equivalent elements have the same reference numerals. Detailed Implementation

[0051] Several methods currently in use affect vehicle handling and yaw behavior, either by using individual wheel friction braking torque (as in the case of an ESC system) or by using powertrain torque vectoring actuators (such as eLSD, TVDC, individual wheel motors, etc.).

[0052] To achieve a specific yaw behavior in a vehicle, a calculated yaw torque needs to be applied at the vehicle level, which can be achieved by either a single system or a combination of both. Current solutions use either a single system or a combination of two systems, but typically there is no communication between them to coordinate and execute the yaw torque. This can result in under-correction or over-correction of the yaw behavior, which may be due to more than one actuator failing to deliver, or delivering more than requested, without compensation from other actuators. This can be achieved through… Figure 2 The TVDC actuator shown here is an example, comprising wheel-specific clutches CL and CR, which are driven by a propulsion system on the axle, similar to... Figure 2The electric motor shown is an example. Without propulsive or regenerative braking torque, the TVDC actuator cannot control the torque of individual wheels and therefore loses its ability to perform torque vectoring. This means the TVDC actuator cannot meet its requested yaw torque, and unless compensated for by other actuators, the requested yaw torque is lost at the vehicle level. Therefore, other actuators, such as individual wheel braking systems, need to compensate to maintain the vehicle's desired yaw behavior.

[0053] The problem will not be recognized by the solutions currently used in vehicles until the yaw behavior does not show the expected change due to the unexecuted yaw torque request, causing other systems (such as ESC) to intervene. This results in delayed control action, as it must wait for changes in the vehicle's response, negatively impacting driving experience and safety.

[0054] Powertrain torque vectoring actuators have been used for quite some time and in conjunction with ESC systems. However, these functions are largely implemented in two different ECUs (Electronic Control Units) and calibrated in a way that works well together, but without any synchronization between them. This limitation of the actuator restricts the possibility of applying an accurate amount of yaw torque, and the possibility of using the appropriate actuator for the driving situation.

[0055] To solve at least one of the above problems, Figure 3 A block diagram of an exemplary yaw motion control system 10 in a vehicle 100 is shown. Typically, the vehicle 100 has at least one axle with two wheels. The vehicle 100 includes a wheel-specific braking system 16 and a power transmission torque vectoring actuator system 18.

[0056] The wheel-individual braking system 16 includes at least one first actuator for applying braking torque to individual wheels of the vehicle. In some examples, the wheel-individual braking system 16 may include a single first actuator, such as an electro-hydraulic braking system for all wheels. In some examples, the wheel-individual braking system 16 may include two or more first actuators, such as an electro-hydraulic actuator for one axle and an electromechanical actuator for one or more other axles. Figure 3 In the example shown, the wheel-specific braking system 16 includes three first actuators 16a, 16b, and 16c. The first actuators may include service brakes, such as, but not limited to, electrohydraulic braking systems, electromechanical braking systems, electromagnetic braking systems, or any combination thereof.

[0057] The powertrain torque vectoring actuator system 18 includes at least one second actuator for applying torque to individual wheels of the vehicle via a propulsion system (e.g., an electric motor). In some examples, the powertrain torque vectoring actuator system 18 may include a single second actuator, such as an eLSD on one axle. In some examples, the powertrain torque vectoring actuator system 18 may include two or more second actuators, such as an eLSD on one axle and torque vectoring differentials on other axles. Figure 3 In the example shown, the powertrain torque vectoring actuator system 18 includes two second actuators 18a and 18b. Examples of the second actuators may include, but are not limited to, wheel-specific electric motors, torque vectoring dual clutches, torque vectoring differentials, electronic limited-slip differentials, or any combination thereof.

[0058] The yaw motion control system 10 includes a central control function module 12, which includes multiple yaw torque controllers, such as Figure 3 Examples of yaw torque controllers shown are 14a, 14b, and 14c. Examples may include, but are not limited to, feedforward controllers, feedback understeer controllers, feedback oversteer controllers, or combinations thereof.

[0059] Each yaw torque controller is configured to receive data including driver input and vehicle motion state to determine its respective yaw torque based on the received data, for controlling the vehicle's yaw behavior. Driver input may include, but is not limited to, driver inputs for throttle, brake, and steering. Figure 3 As shown, vehicle 100 may include a sensor system 20 having one or more sensors for detecting the vehicle's motion state and driver input. Exemplary sensor inputs may include, but are not limited to, yaw rate, wheel speed, lateral acceleration, steering wheel angle, etc.

[0060] The central control module 12 is configured to determine driving conditions based on received data and adjudicate multiple yaw torques from individual yaw torque controllers to determine a single yaw torque based on the driving conditions. Different adjudication strategies can be used, which provide the expected vehicle properties in terms of flexibility and stability.

[0061] The expected vehicle attributes describe the characteristics that the vehicle is expected to have. Examples of expected vehicle attributes may include, but are not limited to, energy efficiency, driving experience, safety, noise, vibration, or any combination thereof. The central control function module 12 is also configured to deliver a yaw torque request to at least one first actuator and / or at least one second actuator to execute a single yaw torque.

[0062] To ensure the accurate achievement of the determined yaw torque, a suitable actuator can be selected to apply the yaw torque, taking into account the various types of limitations and feedback from the actuator on the applied yaw torque. This will be explained further in the following sections, particularly regarding... Figure 4 As shown in the example.

[0063] Figure 4 A block diagram illustrates an overview of an exemplary yaw torque hybrid workflow.

[0064] In Block 2, the central control function module can receive input from the driver, as well as vehicle state estimation and vehicle motion feedback from Block 6. As described above, the multiple yaw torque controllers of the central control function module can determine multiple yaw torques based on the received data, such as forward yaw torque, feedback understeer yaw torque, and feedback oversteer yaw torque, for controlling the vehicle's yaw behavior. These exemplary yaw torques are described below.

[0065] Feedforward yaw torque:

[0066] As the global automotive market moves towards electrification, vehicle weight has been steadily increasing due to the added weight of batteries. This increases yaw inertia, thus making the driving feel less responsive and agile. Therefore, to make the vehicle feel more responsive and mask the effects of high yaw inertia, a feedforward yaw torque can be calculated based on driver intent. This yaw torque helps the driver navigate corners smoothly, and its contribution increases with more active driving. It can be based on... Figure 4 The vehicle motion input in block 6, along with the driver's throttle and steering inputs, are used to calculate the driver's intention.

[0067] Feedback on understeer and yaw torque:

[0068] When driving near the friction limit, the front axle typically begins to saturate and limit lateral forces, especially when there is propulsion torque on the front axle that further reduces lateral force capacity. This limits the amount of yaw torque generated by front lateral tire forces and thus causes understeer. In these situations, corrective yaw torque in the cornering direction can help the driver mitigate understeer. To detect this and quantify the amount of understeer, sensor signals such as wheel speed, yaw rate, and lateral acceleration can be used to calculate the model-based steering angle required for smooth cornering, such as... Figure 4 As shown in block 6. This can then be compared to the actual steering angle and used as a control variable to calculate the appropriate amount of corrected yaw torque.

[0069] Feedback on over-yawing torque:

[0070] Oversteer can occur when a vehicle is driven in a dynamic or steady-state manner close to its friction limits. Conflict avoidance maneuvers are an example of such dynamic maneuvers. In this situation, to reduce oversteer behavior, the yaw rate should be suppressed by applying a corrected yaw torque using a yaw rate controller and by using appropriate limits to avoid intervention when unnecessary. If the yaw torque suppression is insufficient, the vehicle may continue to oversteer, increasing the phase lag between driver input and vehicle response. To reduce phase lag, a corrected yaw torque needs to be applied, which is based on the difference between the vehicle's yaw rate and the driver's expected yaw rate. The driver's expected yaw rate can be calculated using sensor inputs such as steering wheel angle, wheel speed sensors, lateral acceleration, etc.

[0071] Oversteer can also occur when driving in a steady-state manner close to the friction limit. An example of this is when the driver releases the accelerator, applies the brakes, and / or increases steering input while driving at this limit. This causes the load to be transferred from the rear axle to the front axle, reducing the lateral force capacity of the rear wheels and pushing the vehicle into an oversteer situation. In these cases, the yaw rate deviation has a very small value; in other cases, due to an overly sensitive control threshold, this value cannot be used as a control variable without unexpected intervention. Therefore, to mitigate slow oversteer under steady-state driving limit conditions, sideslip on the rear axle can be used as a control variable (with a suitable threshold) to calculate the corrected yaw torque. Sideslip on the rear axle can be calculated using vehicle motion feedback (in... Figure 4 The calculation is performed within block 6 of the system, and it is a good measure of oversteer in these cases because it quantifies the lateral rate of the rear axle, and an excessive lateral rate indicates over-rotation of the vehicle.

[0072] The corrected yaw torque calculated by all individual controllers needs to be adjudicated based on driving conditions, and a single yaw torque value needs to be calculated at the vehicle level. Different adjudication strategies can be used, which give the expected properties in terms of flexibility and stability. The adjudicated yaw torque is then sent from Block 2 to Block 3, where, taking into account various types of constraints and feedback from the yaw torque already applied by the actuators, the central control function module selects the appropriate actuator to apply the corrected yaw torque. This will be explained further in the following sections.

[0073] Actuator capacity limitation

[0074] In some examples, the central control function module may be configured to: receive data indicating the yaw torque capability of each actuator; determine at least one actuator for performing the requested yaw torque based on the yaw torque capability; reallocate the yaw torque request between at least one first actuator and at least one second actuator when necessary; and deliver the yaw torque request to at least one determined actuator.

[0075] In other words, a method is proposed to achieve this vehicle-level corrected yaw torque by using different actuators, such as powertrain torque vectoring systems, wheel-specific braking systems, etc. To do this, it may be necessary to calculate the yaw torque capacity of each individual actuator, which would give an indication of each actuator's ability to deliver the requested yaw torque. For example, in a vehicle configuration where at least two wheels are driven by wheel-specific electric motors and each wheel has a friction brake actuator, the wheel torque capacity can be calculated for the electric motors and the friction brake actuators for each wheel, which can then be used to recalculate the vehicle-level yaw torque capacity. Electric motors typically have speed-dependent torque characteristics calculated from maximum power, and the torque capacity of friction brakes can be calculated based on the brake pad friction coefficient, brake size, and actuator clamping force capacity. If a TVDC actuator is used in conjunction with a single electric motor or internal combustion engine on the axle, the maximum torque delivery capacity of the wheel-specific clutch can be used to calculate the yaw torque capacity. Similar torque capacity calculations can also be performed for eLSDs or any other type of torque vectoring actuators or other types of wheel-specific brake actuators. The calculation can be performed using sensor signals from block 6, and the calculated yaw torque capacity can be used in block 3 as a limit for requesting yaw torque from each actuator.

[0076] Tire capacity limit

[0077] In some examples, the central control function module may be configured to: receive data indicating the tire longitudinal force generation capability of each tire of the vehicle; determine at least one actuator for performing the requested yaw torque based on the tire longitudinal force generation capability; reallocate the yaw torque request between at least one first actuator and at least one second actuator when necessary; and deliver the yaw torque request to at least one determined actuator.

[0078] In other words, another limiting factor to consider is the tire's longitudinal force generation capacity. Depending on the tire's longitudinal force capacity, any amount of wheel torque requested from any actuator can only generate a limited amount of longitudinal force. A tire can generate both longitudinal and lateral forces, but this is limited by the vertical load on the tire and the coefficient of friction of the surface. Various tire models capture this limitation, but for simplicity, it can be visualized using a circle.

[0079] Figure 5 The friction circle and force limit of the tire are shown. Here, F x F represents the longitudinal force generated by the tire. y It is a lateral force, F z Here, μ is the vertical force, and μ is the coefficient of friction of the surface. To calculate the longitudinal force capacity of a tire, the vertical load on the tire needs to be estimated, and this can be done by... Figure 4 Block 6 uses accelerometer signals and various vehicle models for calculations. Examples of modeling techniques include, but are not limited to, the rigid body assumption of the vehicle, or the assumption of sprung and unsprung masses coupled with rotating springs and dampers, or dual-rail models, etc. Different methods can also be used to estimate the surface friction coefficient, such as, but not limited to, utilization-based friction calculations using lateral and longitudinal accelerometer signals, or vision-based friction estimations using cameras, etc. Lateral forces generated by the tires can also be estimated using sensor signals (such as lateral acceleration, steering tire angle, wheel speed, and yaw rate) and different vehicle models (such as, but not limited to, monorail vehicle models, dual-rail vehicle models, etc.). The longitudinal force capacity of each tire can then be calculated using different tire models, using vertical force, friction coefficient, and lateral force.

[0080] The longitudinal force capacity calculated for each tire can be used to calculate the vehicle-level yaw torque capacity using the rail width and wheel radius. This yaw torque capacity can be used in Block 3 as a limit on the yaw torque requested for a particular tire to avoid overutilizing any tire when another tire with a higher capacity to generate longitudinal force can be used.

[0081] Feedback of executed yaw torque

[0082] In some examples, the central control function module can be configured to: receive feedback on the amount of yaw torque already executed; and, if it is determined that the requested yaw torque is under-executed or over-executed, determine one or more additional actuators for executing the requested yaw torque based on the feedback.

[0083] Another important aspect to consider is the amount of yaw torque already performed by the different actuators. This may be necessary because one or more actuators may fail to deliver the requested wheel torque due to physical limitations and actuator delays, limitations from other functions, or some failure mode, resulting in insufficient execution of the requested yaw torque. It is also possible that some actuators deliver more torque than requested, causing over-execution of the requested yaw torque. In these cases, if other actuators do not proactively compensate for the differences, it may lead to undesirable changes in vehicle yaw behavior because the calculated amount of corrected yaw torque will not be applied accurately. In this case, feedback on the amount of wheel torque performed by each actuator (e.g., ...) is needed. Figure 4 The amount of yaw torque performed by each actuator is calculated, as shown in blocks 6 to 3, so that any deficiency or excess can be compensated for by other actuators. An example could be, but is not limited to, a vehicle with an ESC system and an electric motor with a TVDC system on one axle. If the amount of motor torque is limited due to an active traction control request, and the requested yaw torque cannot be met by the TVDC system, feedback of the wheel torque performed by the TVDC system can be provided to calculate the amount of yaw torque delivered by it. The remainder can be sent to the ESC system for execution by the individual friction brakes of the wheel. In this way, an accurate amount of corrected yaw torque can be applied by using several complementary actuators.

[0084] Actuator Priority and Hybrid

[0085] In some examples, such as Figure 4 As shown in block 3, the central control function module can be configured to: receive data indicating expected vehicle attributes describing desired characteristics of the vehicle; determine a priority order of at least one first actuator and at least one second actuator based on driving conditions and expected vehicle attributes; and deliver a yaw torque request to at least one first actuator and at least one second actuator according to the determined priority order. Expected vehicle attributes may be energy efficiency, driving experience, safety, noise, vibration, or any combination thereof.

[0086] In other words, depending on the driving conditions, a priority order can be determined for all actuators. For example, in a vehicle with torque vectoring actuators and wheel-specific friction brake actuators with ESC, when driving significantly below the grip limit, the torque vectoring actuator can be prioritized over the ESC system because it is generally quiet and avoids the pump and valve noise generated by the ESC actuator. This can provide a superior driving experience without compromising agility and safety. Furthermore, if wheel-specific electric motors are used, they can also be energy-efficient because regenerative braking can be used to recover energy that would otherwise be lost as heat if a friction braking system were used. High-speed driving typically reduces the torque capacity of electric motors or internal combustion engines due to power limitations. In these cases, the ESC system can be used instead of the torque vectoring system. For TVDC actuators or eLSDs, the clutch may overheat, potentially resulting in reduced or no torque delivery capacity, and then the ESC system can be used to achieve the requested corrective yaw torque. Beyond these examples, depending on the vehicle's target attributes, there may be other situations where one actuator is preferred over others.

[0087] After prioritizing actuators based on driving conditions, yaw torque limits from actuator capacity and tire longitudinal force capacity may need to be considered in order to execute the corrected yaw torque request. If one or more of these capacity limits are exceeded, the yaw torque should be reallocated to other actuators (according to actuator priority). Feedback on the yaw torque already delivered from different actuators then needs to be considered to determine how much each actuator has been able to deliver compared to the yaw torque it requested for reallocation (according to actuator priority).

[0088] After the above yaw torque mixing process, the final yaw torque request of each actuator needs to be converted into a wheel torque request using various rail widths and tire rolling radii, and then sent from block 3 to wheel slip limit block 4.

[0089] Wheel slip limit

[0090] In wheel slip limiting block 4, the central control function module can be configured to receive feedback on individual wheel longitudinal slip; and to control the maximum yaw torque requested from at least one first actuator and / or at least one second actuator based on the feedback on individual wheel longitudinal slip.

[0091] The longitudinal force generated by a tire depends on the vertical load and longitudinal slippage on the tire. A typical tire force curve for a specific vertical load can be found in... Figure 6 Visualized in the middle, Figure 6The standardized longitudinal tire force characteristics are shown. Longitudinal slip is quantified by the slip ratio, which is the ratio of the difference between the wheel center velocity and its tangential velocity in the tire-road contact area to the wheel center velocity. From Figure 6 As can be seen, the longitudinal force reaches its peak at a certain slip ratio and then gradually decreases as slip increases. Therefore, a large slip ratio reduces the longitudinal force generated by the tire, which in turn reduces the yaw torque generated from the longitudinal tire force. Another effect of large longitudinal slip on the tire is a reduction in the tire's lateral force capacity, which can also cause significant changes in vehicle understeer and oversteer behavior. High longitudinal slip occurs if the actuator requests a significant amount of torque exceeding the tire's grip limit, or if the coefficient of friction changes abruptly. Therefore, limiting the amount of longitudinal wheel slip is crucial to ensure that the amount of yaw torque that can be accurately corrected, preventing unintended reductions in longitudinal and lateral forces. This wheel slip limitation can be ensured by controlling the maximum torque requested from the actuator through feedback control based on individual wheel longitudinal slip. For individual wheel brake actuators, functions such as ABS (Anti-lock Braking System) and EBD (Electronic Brakeforce Distribution) can be used to reduce friction brake torsion. In torque vectoring systems (such as wheel-specific electric motors), traction control systems and regenerative braking control systems can be used to limit the maximum motor torque based on longitudinal wheel slip. This process is as follows: Figure 4 This is completed in block 4, as shown in block 5. Then, the slip-limiting wheel torque request from block 4 is sent to each actuator.

[0092] Figure 7 A flowchart of an exemplary yaw motion control method 200 is shown, which coordinates and synchronizes wheel-specific braking systems and powertrain torque vectoring actuator systems in a vehicle. The wheel-specific braking system includes at least one first actuator for applying braking torque to individual wheels of the vehicle. The powertrain torque vectoring actuator system includes at least one second actuator for applying torque to individual wheels of the vehicle via a propulsion system.

[0093] The at least one first actuator may include a service braking system, which refers to a main braking system, such as, but not limited to, an electrohydraulic braking system, an electromechanical braking system, or any combination thereof. Examples of the at least one second actuator may include, but are not limited to, wheel-specific electric motors, torque vectoring dual clutches, torque vectoring differentials, electronic limited-slip differentials, or any combination thereof.

[0094] In step 210, the method includes receiving data, including driver input and vehicle motion state, from each yaw torque controller in the central control function module. Examples of driver input may include, but are not limited to, the driver's throttle and steering inputs. Vehicle motion state and driver input can be derived from sensor inputs, including but not limited to steering wheel angles, wheel speed sensors, lateral acceleration, etc.

[0095] In step 220, the method includes each yaw torque controller in the central control function module determining its own yaw torque based on the received data, for controlling the yaw behavior of the vehicle.

[0096] Examples of yaw torque controllers may include, but are not limited to, feedforward controllers and feedback controllers.

[0097] Examples of yaw torque may include, but are not limited to, feedforward yaw torque, feedback understeer yaw torque, feedback oversteer yaw torque, or any combination thereof.

[0098] In step 230, the method includes determining the driving situation by the central control function module based on the received data.

[0099] In step 240, the method includes a central control function module adjudicating multiple yaw torques from individual yaw torque controllers to determine a single yaw torque based on driving conditions. Different adjudication strategies can be used, which gives the desired properties in terms of flexibility and stability.

[0100] In step 250, the method includes determining a priority order of at least one first actuator and at least one second actuator based on driving conditions and expected vehicle attributes describing the desired characteristics of the vehicle.

[0101] In step 260, the method further includes coordinating the individual braking systems of the wheels and the powertrain torque vectoring actuator system to execute yaw torque in order to deliver yaw torque requests to at least one first actuator and at least one second actuator according to a determined priority in order to execute a single yaw torque.

[0102] The method includes delivering a yaw torque request to at least one first actuator and / or at least one second actuator to perform a single yaw torque.

[0103] The method may also include the following optional steps, which will... Figure 4 The examples shown will be explained in detail.

[0104] The method may further include the following steps: receiving data indicating the yaw torque capability of each actuator; determining at least one actuator for performing the requested yaw torque based on the yaw torque capability; reallocating the yaw torque request between at least one first actuator and at least one second actuator as needed; and delivering the yaw torque request to at least one determined actuator.

[0105] The method may further include the following steps: receiving data indicating the tire longitudinal force generation capability of each tire of the vehicle; determining at least one actuator for performing the requested yaw torque based on the tire longitudinal force generation capability; reallocating the yaw torque request between at least one first actuator and at least one second actuator when necessary; and delivering the yaw torque request to at least one determined actuator.

[0106] The method may further include the steps of: receiving feedback on the amount of yaw torque executed; and, if it is determined that the execution of the requested yaw torque is insufficient or excessive, determining one or more additional actuators for executing the requested yaw torque based on the feedback.

[0107] The method may further include the steps of: receiving feedback on the longitudinal slip of an individual wheel; and controlling the maximum yaw torque requested from at least one first actuator and / or at least one second actuator based on the feedback on the longitudinal slip of the individual wheel.

[0108] In the examples of this disclosure, a computer program or computer program element is provided, characterized in that it is adapted to perform method steps of a method according to one of the foregoing embodiments on a suitable system.

[0109] Computer program elements can therefore be stored on a computer unit, which may also be part of embodiments of this disclosure. The computing unit can be adapted to perform or cause the execution of steps of the described methods. Furthermore, it can be adapted to operate components of the described apparatus. The computing unit can be adapted to automatically operate and / or execute user commands. The computer program can be loaded into the working memory of a data processor. The data processor can therefore be equipped to perform the methods of this disclosure.

[0110] This disclosure covers both computer programs that use this disclosure from the outset and computer programs that convert existing programs into programs that use this disclosure through updates.

[0111] Furthermore, computer program elements may be able to provide all the necessary steps to complete the exemplary embodiment of the method as described above.

[0112] According to one example of this disclosure, a computer-readable medium, such as a CD-ROM, is presented, wherein the computer-readable medium has computer program elements stored thereon, which are described in the preceding sections.

[0113] Computer programs may be stored and / or distributed on suitable media, such as optical storage media or solid-state media that are supplied together with or as part of other hardware, but may also be distributed in other forms, such as via the Internet or other wired or wireless telecommunications systems.

[0114] However, computer programs can also be presented on networks like the World Wide Web and can be downloaded from such networks into the working memory of a data processor. According to one example of this disclosure, a medium is provided for making computer program elements downloadable, which is arranged to perform a method according to one of the foregoing embodiments of this disclosure.

[0115] From a study of the accompanying drawings, the disclosure, and the appended claims, those skilled in the art can understand and implement other variations of the disclosed embodiments in practicing the claimed invention. In the claims, the word "comprising" does not exclude other elements or steps, and the indefinite articles "a" and "an" do not exclude multiple. A single processor or other unit can perform the functions of several items or steps listed in the claims. The fact that certain measures are listed in mutually different dependent claims does not indicate that a combination of these measures cannot be used advantageously. Computer programs can be stored / distributed on suitable media, such as optical storage media or solid-state media supplied with or as part of other hardware, but can also be distributed in other forms, such as via the Internet or other wired or wireless telecommunications systems. Any reference marks in the claims should not be construed as limiting the scope of the claims.

[0116] Reference tag list

[0117] 10 Vehicle motion control system

[0118] 12 Central Control Function Module

[0119] 14a Yaw Torque Controller

[0120] 14b Yaw Torque Controller

[0121] 14c Yaw Torque Controller

[0122] 16. Individual braking system for each wheel

[0123] 16a First actuator

[0124] 16b First actuator

[0125] 16c First Actuator

[0126] 18 Power Transmission Torque Vectoring Actuator System

[0127] 18a Second Actuator

[0128] 18b Second Actuator

[0129] 20 Second Actuator

[0130] 100 vehicles

Claims

1. A vehicle motion control system (10) for coordinating and synchronizing wheel-individual braking systems (16) and power transmission torque vectoring actuator systems (18) in a vehicle (100), the wheel-individual braking system comprising at least one first actuator (16a, 16b, 16c) for applying braking torque to individual wheels of the vehicle; and the power transmission torque vectoring actuator system comprising at least one second actuator (18a, 18b) for applying torque to individual wheels of the vehicle via a propulsion system; the vehicle motion control system comprising: Central control module (12) includes multiple yaw torque controllers (14a, 14b, 14c). Each yaw torque controller is configured to receive data including driver input and vehicle motion state to determine a respective yaw torque for controlling the yaw behavior of the vehicle based on the received data; as well as The central control module is configured to: determine driving conditions based on received data; and adjudicate multiple yaw torques from individual yaw torque controllers to determine a single yaw torque based on the driving conditions. The priority order of the at least one first actuator and the at least one second actuator is determined based on the driving conditions and the expected vehicle attributes describing the desired characteristics of the vehicle; and the execution of the yaw torque by the individual braking systems of the wheels and the powertrain torque vectoring actuator system is coordinated to deliver the yaw torque request to the at least one first actuator and the at least one second actuator according to the determined priority order in order to execute the single yaw torque, wherein the expected vehicle attributes are configured by the driver and the expected vehicle attributes include driving experience.

2. The vehicle motion control system according to claim 1, The expected vehicle attributes also include at least one of energy efficiency, safety, noise, and vibration.

3. The vehicle motion control system according to claim 1 or 2, The central control module is configured to receive data indicating the yaw torque capability of each actuator. Based on the yaw torque capability, at least one actuator is determined for performing the requested yaw torque; the yaw torque request is reallocated between the at least one first actuator and the at least one second actuator when necessary; And deliver the yaw torque request to at least one determined actuator.

4. The vehicle motion control system according to claim 1 or 2, The central control module is configured to: receive data indicating the longitudinal force generation capability of each tire of the vehicle; determine at least one actuator for performing a requested yaw torque based on the longitudinal force generation capability; reallocate the yaw torque request between the at least one first actuator and the at least one second actuator when necessary; and deliver the yaw torque request to the at least one determined actuator.

5. The vehicle motion control system according to claim 1 or 2, The central control module is configured to receive feedback on the amount of yaw torque executed, and if it is determined that the requested yaw torque is insufficient or excessive, determine one or more additional actuators for executing the requested yaw torque based on the feedback.

6. The vehicle motion control system according to claim 1 or 2, The central control module is configured to receive feedback on the longitudinal slip of individual wheels and to control the maximum yaw torque requested from the at least one first actuator and / or the at least one second actuator based on the feedback on the longitudinal slip of individual wheels.

7. The vehicle motion control system according to claim 1 or 2, The plurality of yaw torque controllers include feedforward controllers, feedback controllers, or any combination thereof.

8. The vehicle motion control system according to claim 1 or 2, The plurality of yaw torques include feedforward yaw torque, feedback understeering yaw torque, feedback oversteering yaw torque, or any combination thereof.

9. A vehicle (100), comprising: - A wheel-specific braking system (16) includes at least one first actuator (16a, 16b, 16c) for applying braking torque to individual wheels of the vehicle; - A power transmission torque vectoring actuator system (18) includes at least one second actuator (18a, 18b) for applying torque to individual wheels of the vehicle via a propulsion system; and - The vehicle motion control system (10) according to any one of the preceding claims is configured to coordinate and synchronize the individual braking systems of the wheels and the power transmission torque vector actuator system.

10. The vehicle according to claim 9, The at least one first actuator includes a service braking system configured to apply braking torque to individual wheels.

11. The vehicle according to claim 9 or 10, The at least one second actuator includes a wheel-specific electric motor, a torque vectoring dual clutch, a torque vectoring differential, an electronic limited-slip differential, or any combination thereof.

12. The vehicle according to any one of claims 9 or 10, further comprising: The sensor system includes one or more sensors for detecting the vehicle's motion state and driver input.

13. A vehicle motion control method (200) for coordinating and synchronizing wheel-individual braking systems and power transmission torque vectoring actuator systems in a vehicle, the wheel-individual braking system comprising at least one first actuator for applying braking torque to individual wheels of the vehicle, and the power transmission torque vectoring actuator system comprising at least one second actuator for applying torque to individual wheels of the vehicle via a propulsion system, the vehicle motion control method comprising the following steps: - Data including driver input and vehicle motion status is received (210) by each yaw torque controller in the central control function module; - Each yaw torque controller in the central control function module determines (220) its own yaw torque based on the received data, for controlling the yaw behavior of the vehicle; - The driving situation is determined (230) by the central control function module based on the received data; - The central control function module determines (240) multiple yaw torques from individual yaw torque controllers to determine a single yaw torque based on the driving conditions; - Determine the priority order of the at least one first actuator and the at least one second actuator, depending on the driving conditions and the expected vehicle attributes describing the desired characteristics of the vehicle; - Coordinate (260) the individual braking system of the wheel and the power transmission torque vector actuator system to execute the yaw torque, so as to deliver the yaw torque request to the at least one first actuator and at least one second actuator according to a determined priority order, so as to execute the single yaw torque, wherein the expected vehicle attributes are configured by the driver and the expected vehicle attributes include driving experience.

14. A computer-readable storage medium having a computer program stored thereon, including instructions for causing a vehicle motion control system according to any one of claims 1 to 8 or a vehicle according to any one of claims 9 to 12 to perform the steps of the method according to claim 13.

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