Coordinated vehicle dynamic maneuver balance control using torque management

Abstract

The invention relates to coordinated vehicle dynamic maneuver balance control using torque management. A chassis control system of a vehicle includes a first torque source providing torque to a first axle of the vehicle; a second torque source providing torque to a second axle of the vehicle independent of the first torque source; and a vehicle control module that controls the first and second torque sources to transition between a torque redistribution mode and a torque limit control mode based on a wheel torque redistribution threshold, a wheel torque limit of the first axle and / or the second axle, and a torque limit of one of the first and second torque sources. The torque redistribution mode refers to when torque is selectively provided by the first torque source to the first axle and by the second torque source to the second axle. The torque limit control mode refers to when torque to at least one of the first axle and the second axle is limited.

Description

[0001] introduction

[0002] The information provided in this section is for the purpose of generally presenting the context of the present disclosure. To the extent described in this section, the works of the presently named inventors and aspects of the description that may not constitute prior art at the time of filing are neither explicitly nor implicitly admitted to be prior art to the present disclosure. Technical Field

[0003] The present disclosure relates to chassis control systems such as vehicle traction control systems, electronic stability control systems, and all-wheel drive systems. Background Art

[0004] Conventional chassis control systems include traction control systems (TCS), electronic stability control (ESC) systems, and all-wheel drive (AWD) systems. TCS systems detect wheel (or tire) slip and apply brakes at one or more wheels and / or reduce torque supplied to one or more wheels. ESC systems detect loss of steering control and apply brakes to improve vehicle stability. AWD systems provide power to all wheels simultaneously or as needed. Summary of the invention

[0005] A chassis control system for a vehicle is disclosed. The chassis control system includes: a first torque source configured to provide torque to a first axle of the vehicle; a second torque source configured to provide torque to a second axle of the vehicle independently of the first torque source; and a vehicle control module configured to control the first torque source and the second torque source to switch between a torque redistribution mode and a torque limit control mode based on a wheel torque redistribution threshold, a wheel torque limit of at least one of the first axle and the second axle, and a torque limit of one of the first torque source and the second torque source, wherein the torque redistribution mode refers to when torque is selectively provided to the first axle by the first torque source and to the second axle by the second torque source, and wherein the torque limit control mode refers to when torque to at least one of the first axle and the second axle is limited.

[0006] In other features, the vehicle control module is configured to switch from the normal torque shaping mode to the torque increasing mode based on the amount of torque requested by a driver of the vehicle and a wheel torque redistribution threshold. During the torque increasing mode, the vehicle control module simultaneously increases torque on the first axle and the second axle.

[0007] In other features, the vehicle control module increases torque on the first axle at a first speed and increases torque on the second axle at a second speed until the torque on the second axle reaches a wheel torque limit of the second axle, at which point the vehicle control module increases torque on the first axle at a third speed and increases torque on the second axle at a fourth speed. The third speed is less than the first speed. The fourth speed is less than the second speed.

[0008] In other features, the vehicle control module is configured to switch from the torque redistribution mode to the torque limiting control mode when the torque on the second axle reaches the wheel torque limit of the second axle, including increasing the torque to the first axle at a fifth speed and increasing the torque to the second axle at a sixth speed. The fifth speed is less than the third speed. The sixth speed is less than the fourth speed.

[0009] In other features, the vehicle control module is configured to limit torque provided to the first axle and avoid increasing torque on the second axle based on a torque limit of the first torque source during operation in the torque limited control mode.

[0010] In other features, the vehicle control module is configured to preemptively increase torque to the first axle and the second axle based on a torque request from a driver of the vehicle.

[0011] In other features, the vehicle control module is configured to transition from preemptively increasing torque to the first axle at a first speed and increasing torque to the second axle at a second speed to operating in a torque increasing mode including increasing torque to the first axle at a third speed and increasing torque to the second axle at a fourth speed. The third speed is less than the first speed. The fourth speed is different from the second speed.

[0012] In other features, the vehicle control module is configured to transition from the torque increasing mode to the torque speed reducing mode, wherein the torque speed reducing mode includes avoiding adding torque to the second axle and maintaining an amount of torque on the second axle below a wheel torque limit of the second axle.

[0013] In other features, the vehicle control module is configured to transition from the torque redistribution mode to the torque limiting control mode when the torque to the first axle reaches a wheel torque limit for the first axle.

[0014] In other features, the vehicle control module is configured to: during the torque limit control mode, transition to a feedback wheel slip control mode; and during the feedback wheel slip control mode, and based on the velocities of the wheels of the first and second axles, adjust the torque of the first axle and allow wheel slip of the first axle, and prevent wheel slip of the second axle and maintain the torque on the second axle at a level below the wheel torque limit of the second axle.

[0015] In other features, the vehicle control module is configured to: determine a lateral acceleration of the vehicle, an amount of torque requested by a driver of the vehicle, a speed of the vehicle, and road surface conditions; determine operating boundaries for an understeer angle and an understeer speed based on the lateral acceleration of the vehicle, the amount of torque requested by a driver of the vehicle, the speed of the vehicle, and road surface conditions; and adjust torque to the first axle and the second axle to maintain operation of the vehicle within the operating boundaries.

[0016] In other features, the first axle is a front axle. The second axle is a rear axle. The vehicle control module is configured to associate the operating boundary with the front and rear wheel slip target curves and adjust the slip of the first axle and the slip of the second axle based on the front and rear wheel slip targets.

[0017] In other features, the vehicle control module is configured to increase the amount of slip of the first axle during the oversteer event and then decrease the amount of slip of the first axle to transition the vehicle toward neutral steering.

[0018] In other features, the vehicle control module is configured to: based on lateral acceleration of the vehicle, an amount of torque requested by a driver of the vehicle, a speed of the vehicle, and road surface conditions, i) increase torque to the second axle to a first level, ii) reduce torque to the second axle from the first level to a second level, and iii) then increase torque to the second axle from the second level to a third level.

[0019] In other features, the vehicle control module is configured to: determine whether the amount of torque requested by the driver is greater than a wheel torque redistribution threshold; in response to the amount of torque requested by the driver being greater than the wheel torque redistribution threshold, provide an amount of torque equal to the torque limit of the first wheel axle from the second torque source to the second wheel axle; and in response to the amount of torque requested by the driver being not greater than the wheel torque redistribution threshold, switch from operating in the torque redistribution mode to the torque limiting control mode.

[0020] In other features, the vehicle control module is configured to: determine whether the amount of torque provided to the second axle is greater than the wheel torque limit of the second axle; in response to the amount of torque provided to the second axle being greater than the wheel torque limit of the second axle, send excess torque to the first axle via the first torque source, the excess torque being the difference between a total torque threshold of the first axle and the wheel torque limit of the second axle; and in response to the amount of torque provided to the second axle being not greater than the wheel torque limit of the second axle, switch from operating in a torque redistribution mode to a torque limiting control mode.

[0021] In other features, the vehicle control module is configured to: determine whether the sum of the torque provided to the first axle and the excess torque is greater than the wheel torque limit of the first axle; in response to the sum being greater than the wheel torque limit of the first axle, distribute the remaining torque between the first axle and the second axle via the first torque source and the second torque source; and in response to the sum not being greater than the wheel torque limit of the first axle, switch from operating in the torque redistribution mode to the torque limiting control mode.

[0022] In other features, a chassis control method is disclosed, and the method includes: determining a lateral acceleration of a vehicle, an amount of torque requested by a driver of the vehicle, a speed of the vehicle, and a road surface condition; determining an operating boundary based on the lateral acceleration of the vehicle, the amount of torque requested by the driver of the vehicle, the speed of the vehicle, and the road surface condition; and controlling a first torque source of a first axle of the vehicle and a second torque source of a second axle of the vehicle to switch between a torque redistribution mode and a torque limiting control mode based on the operating boundary, a wheel torque redistribution threshold, a wheel torque limit of at least one of the first axle and the second axle, and a torque limit of one of the first torque source and the second torque source, wherein the torque redistribution mode refers to when torque is selectively provided to the first axle by the first torque source and to the second axle by the second torque source, and wherein the torque limiting control mode refers to when torque to at least one of the first axle and the second axle is limited.

[0023] In other features, the chassis control method further includes associating an operational boundary with a wheel slip target; and adjusting the wheel slip of the first axle and the wheel slip of the second axle based on the wheel slip target.

[0024] In other features, the chassis control method further includes scheduling non-linear control gains to adjust torque from a first torque source to the first axle and to adjust torque from a second torque source to the second axle based on a driver torque request input and sensor feedback.

[0025] The present invention provides the following technical solutions.

[0026] Technical Solution 1. A chassis control system for a vehicle, the chassis control system comprising:

[0027] a first torque source configured to provide torque to a first axle of the vehicle;

[0028] a second torque source configured to provide torque to a second axle of the vehicle independently of the first torque source; and

[0029] A vehicle control module configured to control the first torque source and the second torque source to switch between a torque redistribution mode and a torque limiting control mode based on a wheel torque redistribution threshold, a wheel torque limit of at least one of the first and second axles, and a torque limit of one of the first and second torque sources, wherein the torque redistribution mode refers to when torque is selectively provided to the first axle by the first torque source and to the second axle by the second torque source, and wherein the torque limiting control mode refers to when torque to at least one of the first and second axles is limited.

[0030] Technical Solution 2. A chassis control system according to Technical Solution 1, wherein:

[0031] The vehicle control module is configured to transition from a normal torque shaping mode to a torque increasing mode based on an amount of torque requested by a driver of the vehicle and the wheel torque redistribution threshold; and

[0032] During the torque increase mode, the vehicle control module increases torque on the first axle and the second axle simultaneously.

[0033] Technical Solution 3. A chassis control system according to Technical Solution 2, wherein:

[0034] the vehicle control module increasing the torque on the first axle at a first speed and increasing the torque on the second axle at a second speed until the torque on the second axle reaches the wheel torque limit of the second axle, at which time the vehicle control module increases the torque on the first axle at a third speed and increases the torque on the second axle at a fourth speed;

[0035] The third speed is less than the first speed; and

[0036] The fourth speed is lower than the second speed.

[0037] Technical Solution 4. A chassis control system according to Technical Solution 3, wherein:

[0038] the vehicle control module configured to switch from the torque redistribution mode to the torque limiting control mode when the torque on the second axle reaches the wheel torque limit of the second axle, including increasing torque to the first axle at a fifth speed and increasing torque to the second axle at a sixth speed;

[0039] The fifth speed is less than the third speed; and

[0040] The sixth speed is lower than the fourth speed.

[0041] Technical Solution 5. A chassis control system according to Technical Solution 4, wherein the vehicle control module is configured to limit the torque provided to the first axle based on the torque limit of the first torque source and avoid increasing the torque on the second axle during operation in the torque limiting control mode.

[0042] Technical Solution 6. A chassis control system according to Technical Solution 1, wherein the vehicle control module is configured to preemptively increase torque to the first axle and to the second axle based on a torque request from a driver of the vehicle.

[0043] Technical Solution 7. A chassis control system according to Technical Solution 6, wherein:

[0044] the vehicle control module being configured to transition from preemptively increasing torque to the first axle at a first speed and to the second axle at a second speed to operating in a torque increasing mode including increasing torque to the first axle at a third speed and to the second axle at a fourth speed;

[0045] The third speed is less than the first speed; and

[0046] The fourth speed is different from the second speed.

[0047] Technical Solution 8. A chassis control system according to Technical Solution 7, wherein the vehicle control module is configured to switch from the torque increase mode to the torque speed reduction mode, wherein the torque speed reduction mode includes avoiding increasing the torque to the second axle and keeping the amount of torque on the second axle below the wheel torque limit of the second axle.

[0048] Technical Solution 9. A chassis control system according to Technical Solution 8, wherein the vehicle control module is configured to switch from the torque redistribution mode to the torque limiting control mode when the torque to the first axle reaches the wheel torque limit of the first axle.

[0049] Technical Solution 10. The chassis control system according to Technical Solution 9, wherein the vehicle control module is configured to:

[0050] During the torque limiting control mode, switching to a feedback wheel slip control mode; and

[0051] During the feedback wheel slip control mode, and based on the velocities of the wheels of the first and second axles, the torque of the first axle is adjusted and the wheel slip of the first axle is allowed, and the wheel slip of the second axle is prevented and the torque on the second axle is maintained at a level below the wheel torque limit of the second axle.

[0052] Technical Solution 11. The chassis control system according to Technical Solution 1, wherein the vehicle control module is configured to:

[0053] determining a lateral acceleration of the vehicle, an amount of torque requested by a driver of the vehicle, a speed of the vehicle, and road surface conditions;

[0054] determining operating boundaries for understeer angle and understeer speed based on the lateral acceleration of the vehicle, the amount of torque requested by the driver of the vehicle, a speed of the vehicle, and the road surface conditions; and

[0055] Torque to the first axle and the second axle is adjusted to maintain operation of the vehicle within the operating boundaries.

[0056] Technical Solution 12. The chassis control system according to Technical Solution 11, wherein:

[0057] The first axle is the front axle;

[0058] The second axle is a rear axle; and

[0059] The vehicle control module is configured to associate the operational boundary with front and rear wheel slip target curves and adjust slip of the first axle and slip of the second axle based on the front and rear wheel slip targets.

[0060] Technical Solution 13. A chassis control system according to Technical Solution 12, wherein the vehicle control module is configured to increase the amount of slip of the first wheel axle during an oversteering event and then reduce the amount of slip of the first wheel axle to cause the vehicle to transition toward neutral steering.

[0061] Technical Solution 14. A chassis control system according to Technical Solution 12, wherein the vehicle control module is configured to: based on the lateral acceleration of the vehicle, the amount of torque requested by the driver of the vehicle, the speed of the vehicle and the road surface condition, i) increase the torque to the second wheel axle to a first level, ii) reduce the torque to the second wheel axle from the first level to a second level, and iii) then increase the torque to the second wheel axle from the second level to a third level.

[0062] Technical Solution 15. The chassis control system according to Technical Solution 1, wherein the vehicle control module is configured to:

[0063] determining whether the amount of torque requested by the driver is greater than the wheel torque redistribution threshold;

[0064] In response to the driver requested torque amount being greater than the wheel torque redistribution threshold, providing an amount of torque from the second torque source to the second axle that is equal to the torque limit of the first axle; and

[0065] In response to the driver requested torque amount not being greater than the wheel torque redistribution threshold, a transition is made from operating in the torque redistribution mode to the torque limiting control mode.

[0066] Technical Solution 16. The chassis control system according to Technical Solution 15, wherein the vehicle control module is configured to:

[0067] determining whether the amount of torque provided to the second axle is greater than a wheel torque limit of the second axle;

[0068] sending excess torque to the first axle via the first torque source, the excess torque being a difference between a total torque threshold for the first axle and the wheel torque limit for the second axle, in response to the amount of torque provided to the second axle being greater than a wheel torque limit for the second axle; and

[0069] In response to the amount of torque provided to the second axle not being greater than the wheel torque limit of the second axle, a transition is made from operating in the torque redistribution mode to the torque limiting control mode.

[0070] Technical Solution 17. The chassis control system according to Technical Solution 16, wherein the vehicle control module is configured to:

[0071] determining whether a sum of the torque provided to the first axle and the excess torque is greater than a wheel torque limit of the first axle;

[0072] In response to the sum being greater than the wheel torque limit of the first axle, distributing remaining torque between the first axle and the second axle via the first torque source and the second torque source; and

[0073] In response to the sum being not greater than the wheel torque limit for the first axle, a transition is made from operating in the torque redistribution mode to the torque limiting control mode.

[0074] Technical Solution 18. A chassis control method, comprising:

[0075] determining a lateral acceleration of a vehicle, an amount of torque requested by a driver of said vehicle, a speed of said vehicle, and road surface conditions;

[0076] determining an operating boundary based on the lateral acceleration of the vehicle, the amount of torque requested by the driver of the vehicle, a speed of the vehicle, and the road surface condition; and

[0077] The first torque source of the first wheel axle of the vehicle and the second torque source of the second wheel axle of the vehicle are controlled to switch between a torque redistribution mode and a torque limiting control mode based on the operating boundary, the wheel torque redistribution threshold, the wheel torque limit of at least one of the first wheel axle and the second wheel axle, and the torque limit of one of the first torque source and the second torque source, wherein the torque redistribution mode refers to when torque is selectively provided to the first wheel axle by the first torque source and to the second wheel axle by the second torque source, and wherein the torque limiting control mode refers to when torque to at least one of the first wheel axle and the second wheel axle is limited.

[0078] Technical Solution 19. The chassis control method according to Technical Solution 18 further includes:

[0079] associating the operating boundary with a wheel slip target; and

[0080] Based on the wheel slip target, the wheel slip of the first axle and the wheel slip of the second axle are adjusted.

[0081] Technical Solution 20. The chassis control method according to Technical Solution 18 also includes: arranging nonlinear control gains to adjust the torque from the first torque source to the first axle and adjust the torque from the second torque source to the second axle based on the driver torque request input and sensor feedback.

[0082] Further areas of applicability of the present disclosure will become apparent from the detailed description, the claims and the accompanying drawings.The detailed description and specific examples are intended for purposes of illustration only and are not intended to limit the scope of the present disclosure. BRIEF DESCRIPTION OF THE DRAWINGS

[0083] The present disclosure will be more fully understood from the detailed description and accompanying drawings, in which:

[0084] Figure 1 is a functional block diagram of a vehicle including an example chassis control system having a vehicle control module with a phase plane module and a wheel slip and yaw module according to the present disclosure;

[0085] Figure 2is a functional block diagram of an example vehicle according to the present disclosure, the example vehicle including independently controlled torque sources controlled via a vehicle control module;

[0086] Figure 3 is a functional block diagram of another example of a vehicle according to the present disclosure, the vehicle including independently controlled torque sources controlled via a vehicle control module;

[0087] Figure 4 is an example graph of understeer angle versus understeer speed according to the present disclosure, illustrating three different operating boundaries based on different sets of operating parameters and road conditions;

[0088] Figure 5 is an example graph of front axle wheel slip versus rear axle wheel slip according to the present disclosure, including example understeer curves, neutral steering curves, and oversteer curves based on different sets of operating parameters and road conditions;

[0089] Figure 6 is an example graph of understeer angle versus understeer speed including example torque amounts to be supplied to the front and rear axles in accordance with the present disclosure;

[0090] Figure 7 is an example torque versus time graph illustrating transitions between a torque redistribution mode and a torque limiting control mode for a curve exit event with high friction road surface conditions and a driveline primarily driven by the rear wheels in accordance with the present disclosure;

[0091] Figure 8 is another example torque versus time graph according to the present disclosure illustrating transitions between a torque redistribution mode, a torque limiting control mode, and a feedback wheel slip control mode for a straight-line acceleration event with low-friction road surface conditions and a driveline system primarily driven by the rear wheels;

[0092] Fig. 9 A chassis control method according to the present disclosure is illustrated, which includes switching between a torque redistribution mode and a torque limiting control mode;

[0093] Fig.10 is an example graph of understeer angle versus time relative to example operating boundaries for different example operating modes in accordance with the present disclosure;

[0094] Fig.11 According to the present disclosure, Fig.10 An example graph of understeer angle versus understeer speed for example operating boundaries of an example operating mode;

[0095] Fig.12 According to the present disclosure Figure 10 to Figure 11 Example graphs of steering angle versus time for example operating modes;

[0096] Fig.13 According to the present disclosure Figures 10 to 12 Example graphs of front axle torque versus time for example operating modes;

[0097] Fig.14 According to the present disclosure Figures 10 to 13 An example graph of rear axle torque versus time for an example operating mode of FIG. 1 ; and

[0098] Fig.15 According to the present disclosure Figure 6 An example of a chart that uses a control chart.

[0099] In the drawings, reference numerals may be repeated to identify similar and / or identical elements. DETAILED DESCRIPTION

[0100] Maintaining consistent vehicle handling (balance) with a human driver in the loop is a complex problem, especially in highly dynamic driving scenarios, such as racetrack driving and / or when driving on low friction road surfaces (e.g., road surfaces covered with ice or snow). TCS systems and ESC systems primarily employ torque limiting control to manage the vehicle's wheel slip and yaw stability. AWD systems typically use torque redistribution control to manage vehicle dynamics. These systems have limited control and operate independently.

[0101] The examples set forth herein include chassis control systems and methods for seamlessly bridging the differences between conventional TCS systems, ESC systems, and AWD systems. The disclosed chassis control system provides a smooth transition between a TCS and / or ESC system providing torque limiting control and an AWD system providing torque redistribution. This is done to enable improved handling dynamics and drivability on and off the racetrack. The disclosed examples are intended to provide a consistent and tunable driver-centric vehicle handling balance by providing coordination between torque limiting control and torque redistribution.

[0102] Examples include i) interpreting the driver's intended vehicle handling balance, ii) preemptive torque control, and iii) integrated feedback control to simultaneously control wheel slip and vehicle understeer dynamics. Interpretation of the driver's intended vehicle handling balance includes: i) defining vehicle handling balance operating boundaries based on parameters such as lateral acceleration, road surface conditions, propulsion torque requested by the driver, and vehicle velocity, ii) associating the operating boundaries with wheel slip targets, and iii) scheduling nonlinear control gains (i.e., torque to each axle) based on driver inputs and feedback from vehicle sensors. Preemptive control includes: i) seamlessly transitioning between torque redistribution modes and torque limiting control modes to achieve a target vehicle handling balance state, and ii) transitioning to feedback wheel slip control, as further described below.

[0103] Figure 1 A vehicle 100 is shown including a chassis control system 102 having a vehicle control module 104. The vehicle control module 104 includes a phase plane module 106 and a wheel slip and yaw module 108. The phase plane module 106 operates based on the relationship between the understeer angle and the understeer speed. The phase plane module 106 controls the yaw behavior of the vehicle 100 and its chassis by keeping the yaw dynamics (or behavior) of the chassis within the set driver controllable boundaries to allow the vehicle 100 to be driven with maximum controllability. Enhanced vehicle control is provided within the limits of the actuator authority to keep the vehicle 100 in a balanced handling state. The wheel slip and yaw module 108 performs intelligent switching between managing i) the relative slip target between the front axle and the rear axle (or multiple front axles and multiple rear axles) and ii) the slip of each wheel to maximize handling performance. In an embodiment, the modules 106, 108 are software modules executed by the vehicle control module 104. The operations performed by the modules 106, 108 are further described below.

[0104] The vehicle 100 also includes sensors 110, memory 112, an accelerator pedal actuator 114, a steering system 116, and a propulsion system 118. The sensors 110 may include wheel rate sensors 120, vehicle rate sensors 122, yaw rate sensors 124, inertial measurement units (IMUs) 126, acceleration sensors (e.g., longitudinal and lateral acceleration sensors) 128, and other sensors 130. The memory 112 may store sensor data 132, operating boundary information 134, applications 136, parameters 138, etc. The sensor data 132 may include data collected from the sensors 110 and / or other sensors such as an accelerator position sensor 140 of the accelerator pedal actuator 114 and a steering angle sensor 142 of the steering system 116. The accelerator pedal actuator 114 and the accelerator position sensor 140 and / or other devices mentioned herein may be connected to the vehicle control module 104 via a controller area network (CAN) or other network bus 143. The operating boundary information 134 may include equations, tables, etc. for determining the edges, size, and shape of the operating boundaries. The operating boundaries refer to the understeer angle, understeer speed, and understeer angle and understeer speed boundaries described below. The vehicle control module 104 may control the propulsion system 118 based on the sensor data to maintain operation within a selected one of the operating boundaries. The application 136 may include the modules 106, 108, and / or other applications.

[0105] The propulsion system 118 may include two or more torque sources, such as one or more motors and / or one or more engines (eg, internal combustion engines). Figure 1 In the example shown in , the vehicle 100 includes an engine and one or more motors 152. The torque sources are independently controlled. The propulsion system includes a motor control system 154 and a motor control module 156, the motor control system 154 includes one or more motors 152, and the motor control module 156 can control the operation of the one or more motors 152 based on signals from the vehicle control module 104.

[0106] The vehicle control module 104 may also include a mode selection module 160 and / or a parameter adjustment module 162. The modules 106, 108, 160 may select different operating modes, such as a redistribution mode, a torque limit control mode, a conversion (or partial torque redistribution and partial torque limit control) mode, a normal torque shaping mode, a front and rear axle torque increase mode, a front and rear axle torque speed reduction mode, a dynamic torque shaping mode, a preemptive torque distribution mode, a feedback wheel slip control mode, a neutral steering mode, an understeer mode, an oversteer mode, a countersteer mode, a drift mode, a drop throttle mode, a recovery mode, etc. The vehicle may be operated in two or more of these modes simultaneously. The torque redistribution mode refers to when torque is selectively provided to the front and rear axles of the vehicle 100. The torque limit control mode refers to when torque to the front and / or rear axles is being limited. The operating modes are further described below.

[0107] Figure 2 A vehicle 200 is shown including independently controlled torque sources controlled via a vehicle control module 202. The torque sources include a motor 206 and an engine 208. The torque sources may include other torque sources (e.g., two or more motors). The vehicle control module 202 may communicate with Figure 1 The vehicle control module 104 is similarly configured and operated. The vehicle control module 202 controls the operation of the torque sources to control the amount of torque received by one or more front axles 210 and one or more rear axles 212 and thus to the front wheels 214 and rear wheels 216. Such control includes torque-based control as described below for the various operating modes disclosed.

[0108] Figure 3 A vehicle 300 is shown including independently controlled torque sources controlled via a vehicle control module 302. The torque sources include one or more front motors 304 (two are shown) and one or more rear motors 306 (two are shown). The vehicle control module 302 may be coupled to a Figure 1 The vehicle control module 104 is similarly configured and operated. The vehicle control module 302 controls the operation of the torque sources to control the amount of torque received by one or more front axles 310 and one or more rear axles 312 and thus to the front wheels 314 and rear wheels 316. Such control includes torque-based control as described below for the various operating modes disclosed.

[0109] Figure 4A graph showing the relationship between understeer angle and understeer speed illustrates three different operating boundaries based on different sets of operating parameters and road conditions. Three example boundaries 400, 402, 404 are shown for three different sets of operating parameters and road conditions. The operating parameters include vehicle speed Vx, propulsion torque request Torq, and lateral acceleration Ay. Road conditions refer to the level of friction experienced between the tires and the road surface of the corresponding vehicle. High Mu refers to a road surface with a high associated friction level and therefore high tire traction (such as when driving on a dry asphalt road). Medium Mu refers to a road surface with a medium associated friction level and therefore medium tire traction (such as when driving on a gravel or wet road). Low Mu refers to a road surface with a low associated friction level and therefore low tire traction (such as when driving on an ice or snow covered road). Boundary 400 is associated with low Ay, low Mu, high Torq, and low Vx. Boundary 402 is associated with high Ay, high Mu, high Torq, and medium Vx. Boundary 404 is associated with high Ay, high Mu, medium Torq, and high Vx. Many other boundaries can be determined and / or selected based on the values ​​of Ay, Mu, Torq, and Vx.

[0110] Vehicle control modules (e.g. Figures 1 to 3 The vehicle control module (one of the vehicle control modules) determines the parameters Ay, Mu, Torq, and Vx, and determines and / or selects operating boundaries based on these parameters. The edges, size, and shape of the operating boundaries can be determined using equations, lookup tables, etc., and / or can be selected from pre-stored boundaries. The operating boundaries can be determined as non-linear functions of Ay, Mu, Torq, and Vx. The operating boundaries include understeer angle limits and understeer speed limits maintained therein by the vehicle control module. The vehicle control module adjusts the torque levels to the front and rear axles to remain within the specified understeer angle and understeer speed limits. Figure 4 , a positive understeer angle refers to an understeer level, an understeer angle of 0° refers to a neutral steering level, and a negative understeer angle refers to an oversteer level.

[0111] Assuming the vehicle is a bicycle model, the understeer phase map can be estimated using equations 1 and 2, where α Under is the understeer angle, ∝ F is the front tire slip angle, ∝ R is the rear tire slip angle, δ is the steering angle, L is the distance between the centers of the front and rear wheels, is the maximum lateral acceleration experienced by the vehicle's center of gravity (CG), L f is the distance between the center of the vehicle's front wheels and the CG, L r is the distance between the center of the vehicle's rear wheels and the CG, is the yaw velocity, μ is the forward velocity, and g is the gravity.

[0112]

[0113]

[0114] Figure 5 A graph showing the relationship of wheel slip at the front axle to wheel slip at the rear axle includes an example understeer curve 500, an example neutral steer curve 502, a first example oversteer curve 504, and a second example oversteer curve 506. The curves are determined based on Ay, Mu, Torq, and Vx. Neutral steer refers to the situation when there is a one-to-one relationship between front wheel slip (front wheels (or tires)) and rear wheel slip (rear wheels (or tires)). Understeer refers to when the front wheel slip is higher than the rear wheel slip. Oversteer refers to when the rear wheel slip is higher than the front wheel slip.

[0115] Vehicle control modules (e.g. Figures 1 to 3 ) determines parameters Ay, Mu, Torq, and Vx, and based on these parameters determines whether to follow and / or target an understeer curve, a neutral steering curve, or an understeer curve (such as one of the curves shown). For example, curve 500 can be selected as the regenerative slip target. When Ay is high, Mu is high, Torq is medium, and Vx is high, curve 502 can be followed and / or targeted. When Ay is high, Mu is high, Torq is high, and Vx is medium, curve 504 can be followed and / or targeted. When Ay is low, Mu is low, Torq is high, and Vx is low, curve 506 can be followed and / or targeted.

[0116] The determined and / or selected operational boundaries are associated with front and rear wheel slip targets (such as one of the example curves 500, 502, 504, 506 or other front and rear wheel slip relationship curves). The slope of the selected curve defines the vehicle dynamics for understeer and oversteer. For example, if the curve 506 is targeted, the vehicle control module allows a large amount of initial rear wheel slip (as shown by the lower left portion of the curve 506) to rotate the corresponding vehicle into the turn, and as the wheel slip develops, the balance of the vehicle shifts from oversteer to neutral steering to enhance traction and driver confidence, as shown by the upper right portion of the curve 506.

[0117] Figure 6 A graph 600 showing understeer angle versus understeer speed includes a voltage to be supplied to a vehicle (eg, Figures 1 to 3Example amounts of torque for the front and rear axles of a vehicle (one of the vehicles of FIG. 1 ). The chart provides a method for arranging nonlinear control gains (or nonlinear amounts of output torque of a torque source) based on driver inputs (e.g., throttle pedal position and steering angle) and actual vehicle feedback from sensors. Operating boundaries 602 are shown together with i) negative torque values ​​of one or more torque sources of one or more rear axles that supply torque to the rear wheels and ii) positive torque values ​​of one or more torque sources of one or more rear axles that supply torque to the rear wheels. These torque values ​​are provided based on Ay, Mu, Torq, and Vx values. A positive torque value refers to transferring torque toward one or more front axles. A negative torque value refers to transferring torque toward one or more rear axles. A zero torque value refers to no transfer of torque between the front and rear axles. When the vehicle control module operates within operating boundaries 602, torque can be supplied to both the front and rear axles.

[0118] Under certain conditions, the vehicle control module may transition from operating near the top portion of the operating boundary to the bottom portion of the operating boundary. This may occur, for example, when the corresponding vehicle is exiting a turn and accelerating away from the turn. As the vehicle control module moves from the top of the operating boundary to the bottom of the operating boundary, the torque value increases, decreases slightly, and then increases again. The larger initial increase in torque (or torque transfer) from the rear axle(s) to the front axle(s) is intended to stabilize the vehicle and mitigate the initial break away event. If the oversteer continues, the vehicle control module determines that the oversteer is intended by the driver.

[0119] Although the following Figures 7 and 8 The description is for a vehicle driven primarily by the rear wheels, but similar operations can be performed for a vehicle driven primarily by the front wheels. Operations described with respect to the rear axle will be performed with respect to the front axle and vice versa. In addition, limits and thresholds will be adjusted accordingly. Figures 7 and 8 The operations described may be performed by one of the vehicle control modules disclosed herein.

[0120] Figure 7 A torque versus time graph is shown illustrating the transition between a torque redistribution mode and a torque limiting control mode for a curve exit event with high friction road surface conditions and a driveline system driven primarily by the rear wheels. A driver total torque request curve 700, a rear axle torque curve 702 for a vehicle with a single rear axle, and a front axle torque curve 704 for a vehicle with a single front axle are shown. A rear engine torque limit (or first torque source limit) 706, a rear wheel limit 708, a rear wheel redistribution threshold 710, a front motor torque limit (or second torque source limit) 712, and a front wheel limit 714 are shown.

[0121] Figure 7 The example of 719 illustrates a transition from being in a torque redistribution mode to a torque limiting control mode, as represented by bar 719. This includes transitioning from initially being in a normal torque shaping mode 720 to a front and rear axle torque increase mode 722, to a front and rear axle torque speed reduction mode 724, and then to a dynamic torque shaping mode 726. Modes 720, 722 may refer to torque redistribution modes. Mode 724 may refer to a partial torque redistribution and torque limiting control (or transition) mode.

[0122] During mode 720, the amount of torque requested from the driver increases at a first rate. The vehicle control module increases the rear axle torque (or torque to one or more rear axles) to accommodate the increase in driver requested torque. When the rear torque reaches the rear wheel redistribution threshold, the vehicle control module transitions to mode 722.

[0123] During mode 722, the vehicle control module increases both the rear axle torque and the front axle torque (or torque to one or more front axles). The rear axle torque increases at a second speed. The second speed is less than the first speed experienced during mode 720. The front axle torque can increase at a second speed or a different speed. Torque is increased at both axles to prevent an unbalanced situation. At the end of mode 722, the rear axle and the front axle begin to slip simultaneously. Mode 722 begins when the amount of rear axle torque reaches a rear wheel redistribution threshold, which can be preset and / or adjusted. In an embodiment, the rear wheel redistribution threshold is set arbitrarily.

[0124] At the end of mode 722, the front and rear axles may begin to slip. Front axle slippage results in understeer. Rear axle slippage results in oversteer. If both axles slip the same amount at the same time, neutral steering occurs.

[0125] During mode 724, the rear axle torque and the front axle torque increase. The rear axle torque increases at a third speed that is less than the second speed. The front axle torque may increase at the third speed or another speed. The front axle torque increases at a slower speed than experienced during mode 722. During mode 724, the vehicle control module switches between the torque redistribution mode to the torque limit control (or torque limit) mode.

[0126] During mode 726, the rear axle torque increases at a fourth speed that is less than the third speed. During this mode, the front axle torque does not increase. The front axle torque is at the front motor limit. The rear axle torque is limited by the rear engine limit.

[0127] In the example shown, the normal torque shaping mode is implemented when the vehicle begins to exit the curve, operates in modes 722, 724 during the middle portion of the exit event, and operates in the dynamic torque shaping mode at the end of the exit from the curve. After exiting the curve when the amount of torque requested by the driver is reduced, the vehicle control module can operate in modes 720, 722, 724, 726 in the reverse order.

[0128] In an embodiment, the transition phase entry and exit thresholds for mode 724 are calculated based on the predicted time to reach maximum motor capacity or the tire limit on the front axle (before slip), whichever is sooner.

[0129] Figure 8 A torque versus time graph is shown illustrating transitions between a torque redistribution mode, a torque limit control mode, and a feedback wheel slip control mode for a straight-line acceleration event with low friction road surface conditions and a driveline system primarily driven by the rear wheels. A driver total torque request curve 800, a rear axle torque curve 802 for a vehicle with a single rear axle, and a front axle torque curve 804 for a vehicle with a single front axle are shown. A rear engine torque limit (or first torque source limit) 806, a front motor torque limit (or second torque source limit) 808, a rear wheel limit 810, a front wheel limit 812, and a rear wheel redistribution limit 814 are shown.

[0130] Figure 8 The example of illustrates a transition from being in a torque redistribution mode to a torque limiting control mode. This includes a transition from initially being in a preemptive torque distribution mode 820 to a front and rear axle torque increase mode 822, to a front and rear axle torque speed reduction mode 824, and then to a dynamic torque shaping mode 826. Modes 820, 822, 824 may refer to torque redistribution modes. The beginning (or first portion) of mode 826 may refer to a partial torque redistribution and partial torque limiting control (or transition) mode. The second portion of mode 826 may refer to a torque limiting control mode.

[0131] During mode 820, the amount of torque requested from the driver increases at a first rate. The vehicle control module increases the rear axle torque and the front axle torque to accommodate the increase in the driver's requested torque. In addition to sending torque to the rear axle (or multiple rear axles), the preemptive torque is also sent to the front axle (or multiple front axles). The ramp rate of the torque to the front axle can be the same or different from the ramp rate of the torque to the rear axle. In the example shown, the amount of torque provided to the front axle is less than the amount of torque provided to the rear axle. The ramp rate of the torque provided to the front axle is also less than the ramp rate of the torque provided to the rear axle.

[0132] During mode 822, the vehicle control module increases both the rear axle torque and the front axle torque. During mode 820, the rate of increase of the rear axle torque is less than the rate of increase of the rear axle torque. The front axle torque increases to a level slightly below the front wheel limit 812. As an example, the front wheel torque can be equal to 95-98% of the front wheel limit 812. During mode 822, the front axle torque can change at different speeds, as shown. During mode 822, torque is increased at both axles to prevent an unbalanced condition. At the end of mode 822, the rear axle and the front axle begin to slip simultaneously. When the amount of rear axle torque reaches the rear wheel redistribution limit, mode 822 begins.

[0133] During mode 824, the rear axle torque increases and the front axle torque remains constant. The ramp rates of the front and rear axle torques may be reduced. The ramp rate of the rear axle torque may be the same or less than the rate used during mode 822. The ramp rate of the front axle torque is reduced to zero.

[0134] When the rear axle torque reaches the rear wheel torque limit, mode 826 is executed and the vehicle control module switches from the torque redistribution mode to the torque limiting control mode. The vehicle control module operates in the dynamic torque shaping mode and switches to the closed loop wheel slip control. This transition occurs at the beginning of the torque limiting control mode 826, as shown by region 828. At the end of the transition, the vehicle control module operates in the feedback wheel slip control mode, as shown by Figure 8 830. During the feedback wheel slip control mode, the rear axle is experiencing a low level of slip and the front axle is outputting an amount of torque slightly less than the amount required to cause slip in the front axle. The level of torque provided to the front axle is provided to maintain steering. During the feedback wheel slip control mode, closed loop control is performed. The vehicle control module can track the velocity between the front wheels and the rear wheels and strive to maintain a target amount of torque to the rear wheels.

[0135] In an embodiment, the rear axle torque is maintained slightly above the rear wheel limit (the torque level at which the rear wheels begin to slip). The front axle torque is maintained below the front wheel limit to promote neutral handling and steering feel for the driver. Similar control can be achieved for vehicles that are primarily driven by the front wheels.

[0136] Fig. 9 A chassis control method including switching between a torque redistribution mode and a torque limiting control mode is shown. The following operations may be performed iteratively. The following operations may be performed by Figure 1The vehicle control module 104 and / or the wheel slip and yaw module 108 and / or other modules disclosed herein are performed. The following operations are applicable to vehicles having one or more front axles and / or one or more rear axles. References to the front axles refer to the one or more front axles, and the torque provided to the front axles is allocated to the one or more front axles. References to the rear axles refer to the one or more rear axles, and the torque provided to the rear axles is allocated to the one or more rear axles. Operations 900, 902, 904, 906, 908, 910, 912, 914, 916 are associated with torque redistribution control. Operations 918, 920, 922 are associated with torque limit control. At 900, the vehicle control module 104 determines the total driver requested torque. This can be based on the throttle position.

[0137] At 902, the vehicle control module 104 determines whether the total driver request torque is greater than the rear torque redistribution threshold. If so, operation 904 is performed, otherwise operation 918 is performed. At 904, the vehicle control module 104 provides the total rear threshold level of torque to the front axle. The total rear threshold level refers to the torque output limit of the torque source of the rear axle.

[0138] At 906, the vehicle control module 104 determines whether the amount of torque provided to the front axle is greater than the front wheel limit (referred to as the front tire capacity) at which the front wheels begin to slip. At 908, the vehicle control module 104 provides excess torque back to the rear axle. The excess torque refers to the difference between the total rear threshold torque and the front tire capacity.

[0139] At 910, the vehicle control module 104 determines whether the amount of rear torque plus excess torque is greater than the rear wheel limit (referred to as rear tire capacity). If so, operation 912 is performed, otherwise operation 918 is performed. At 912, the vehicle control module 104 distributes the remaining torque between the front and rear axles based on vehicle dynamic conditions.

[0140] At 914, the vehicle control module 104 determines whether the torque provided to the front axle is greater than the front torque limit. If so, operation 916 is performed, otherwise operation 918 is performed. At 916, the vehicle control module 104 sends the remaining excess torque to the rear axle and reduces the rate of change of the rear axle torque. Operation 900 can be performed after operation 916.

[0141] At 918, the wheel slip and yaw module 108 determines whether the rear wheel slip rate is greater than the front wheel slip rate. If not, operation 920 is performed, otherwise operation 922 is performed. At 920, the wheel slip and yaw module 108 determines whether the yaw rate of the corresponding vehicle indicates an oversteer event. If so, operation 922 is performed, otherwise operation 900 is performed. At 922, the wheel slip and yaw module 108 reduces the amount of torque provided to the rear axle.

[0142] The following Figures 10 to 14 are example charts for neutral steer, countersteer, drift, drop throttle, and recovery operating modes. The example charts are for a vehicle with one or more front axles and one or more rear axles. Fig.10 and Figure 12 to Figure 14 The following description is about the front axle and the rear axle. Fig.10 and Figure 12 to Figure 14 In the description of the invention, reference to "front axle" refers to one or more front axles, and reference to "rear axle" refers to one or more rear axles.

[0143] Fig.10 and Figure 12 to Figure 14 Each of includes a curve, wherein portions of the curve are respectively associated with neutral steering, counter steering, drift, drop throttle, and recovery operating modes. Fig.10 and Figure 12 to Figure 14 Provided as an example and associated with the same sequence of events. One of the vehicle control modules disclosed herein may be in a Fig.10 The understeer angle and Fig.11 The vehicle control module monitors the vehicle's understeer angle, understeer speed, and steering angle, and adjusts the amount of torque provided to the vehicle's front and rear axles based on these parameters and the operating boundaries mentioned below, as determined by Figure 13 to Figure 14 The diagram of the steering angle is given by Fig.12 supply.

[0144] Fig.10 A graph of understeer angle versus time is shown relative to an example operational boundary 1000. The operational boundary 1000 is associated with oversteer without vehicle spin. Figure 1 The phase plane module 106 prevents the vehicle from spinning by operating within the operational boundaries as described herein. In an embodiment, the phase plane module 106 allows the vehicle to slide, such as when operating in a drift mode, but prevents vehicle operation from causing the vehicle to spin. The graph includes a curve 1002 having portions A, B, C, and D, which are associated with a counter-steering mode, a drift mode, a drop throttle mode, and a recovery mode, respectively. These modes can be executed by a vehicle control module.

[0145] Fig.11 A graph of understeer angle versus understeer speed is shown relative to an example operating boundary 1100. Points in region 1102 are associated with drift mode B. Points in region 1104 are associated with drop throttle mode C. Points in region 1106 are associated with recovery mode D. Fig.11 The other points are associated with the reverse steering mode A.

[0146] Fig.12 A graph showing the relationship between steering angle and time is shown. The graph includes a curve 1200 including portions A, B, C, D associated with a counter-steer mode, a drift mode, a drop throttle mode and a recovery mode, respectively.

[0147] Fig.13 is an example graph of front axle torque versus time. The graph includes a curve 1300 including portions A, B, C, D associated with a countersteer mode, a drift mode, a drop throttle mode, and a recovery mode, respectively.

[0148] Fig.14 is an example graph of rear axle torque versus time. The graph includes a curve 1400 including portions A, B, C, D associated with a countersteer mode, a drift mode, a drop throttle mode, and a recovery mode, respectively.

[0149] Fig.15 Shown in figure Figure 6 An example of a control map 1500 for use with graph 600 is shown. The graph is a graph of understeer angle versus understeer speed, including example amounts of torque supplied to the front and rear axles. Sensor inputs from, for example, a steering angle sensor 1502, a yaw rate sensor 1504, and a wheel velocity sensor 1506 are shown. Actual understeer dynamics 1508 and manipulated understeer dynamics 1510 are determined based on the outputs of the sensors 1502, 1504, 1506. An amount of torque transfer for transferring an amount of torque between the front and rear axles is determined based on the actual understeer dynamics 1508 and the manipulated understeer dynamics 1510. A control command 1512 is then generated to provide the amount of torque transfer.

[0150] The previous description is merely illustrative in nature and is in no way intended to limit the present disclosure, its application or use. The broad teachings of the present disclosure can be implemented in many forms. Therefore, although the present disclosure includes specific examples, the true scope of the present disclosure should not be so limited, because after studying the drawings, the specification and the appended claims, other modifications will become apparent. It should be understood that one or more steps in the method can be performed in different orders (or simultaneously) without changing the principles of the present disclosure. In addition, although each embodiment is described above as having certain features, any one or more of those features described with respect to any embodiment of the present disclosure can be implemented in any other embodiment and / or combined with the features of any other embodiment, even if the combination is not explicitly described. In other words, the described embodiments are not mutually exclusive, and the arrangement of one or more embodiments to each other is still within the scope of the present disclosure.

[0151] Spatial and functional relationships between elements (e.g., between modules, circuit elements, semiconductor layers, etc.) are described using various terms, including "connected," "engaged," "coupled," "adjacent," "immediately next to," "on top of," "above," "below," and "disposed on." Unless explicitly described as "directly," when describing a relationship between a first element and a second element in the above disclosure, the relationship may be a direct relationship in which no other intermediate elements exist between the first element and the second element, but may also be an indirect relationship in which one or more intermediate elements (spatially or functionally) exist between the first element and the second element. As used herein, the phrase "at least one of A, B, and C" should be interpreted as representing a logical (A or B or C) using a non-exclusive logical "or," and should not be interpreted as representing "at least one of A, at least one of B, and at least one of C."

[0152] In the drawings, the direction of the arrows generally indicates the flow of information (such as data or instructions) of interest to the illustration. For example, when component A and component B exchange various information, but the information transmitted from component A to component B is relevant to the illustration, the arrow may point from component A to component B. This one-way arrow does not mean that no other information is transmitted from component B to component A. In addition, for information transmitted from component A to component B, component B may send a request for the information to component A or receive an acknowledgment.

[0153] In this application, including the definitions below, the term "module" or the term "controller" may be replaced with the term "circuit". The term "module" may refer to, be a part of, or include: an application-specific integrated circuit (ASIC); a digital, analog, or mixed analog / digital discrete circuit; a digital, analog, or mixed analog / digital integrated circuit; a combinational logic circuit; a field programmable gate array (FPGA); a processor circuit (shared, dedicated, or group) that executes code; a memory circuit (shared, dedicated, or group) that stores code executed by the processor circuit; other suitable hardware components that provide the described functionality; or a combination of some or all of the above, such as in a system on a chip.

[0154] The module may include one or more interface circuits. In some examples, the interface circuit may include a wired or wireless interface connected to a local area network (LAN), the Internet, a wide area network (WAN), or a combination thereof. The functions of any given module of the present disclosure may be distributed in multiple modules connected via the interface circuit. For example, multiple modules may allow load balancing. In another example, a server (also referred to as a remote or cloud) module may perform some functions on behalf of a client module.

[0155] As used above, the term "code" may include software, firmware, and / or microcode, and may refer to a program, a routine, a function, a class, a data structure, and / or an object. The term "shared processor circuit" covers a single processor circuit that executes some or all of the code from multiple modules. The term "group processor circuit" covers a processor circuit that is combined with an additional processor circuit to execute some or all of the code from one or more modules. References to multiple processor circuits cover multiple processor circuits on discrete dies, multiple processor circuits on a single die, multiple cores of a single processor circuit, multiple threads of a single processor circuit, or a combination of the above. The term "shared memory circuit" covers a single memory circuit that stores some or all of the code from multiple modules. The term "group processor circuit" covers a memory circuit that is combined with an additional memory to store some or all of the code from one or more modules.

[0156] The term "memory circuit" is a subset of the term computer-readable medium. As used herein, the term "computer-readable medium" does not cover transient electrical or electromagnetic signals propagated through a medium such as a carrier wave; thus, the term computer-readable medium may be considered to be both tangible and non-transitory. Non-limiting examples of non-transitory tangible computer-readable media are non-volatile memory circuits (such as flash memory circuits, erasable programmable read-only memory circuits, or mask read-only memory circuits), volatile memory circuits (such as static random access memory circuits or dynamic random access memory circuits), magnetic storage media (such as analog or digital magnetic tape or hard disk drives), and optical storage media (such as CDs, DVDs, or Blu-ray discs).

[0157] The apparatus and methods described in this application may be implemented in part or in whole by a special-purpose computer, which is created by configuring a general-purpose computer to perform one or more specific functions embodied in a computer program. The functional blocks, flow chart components and other elements described above are used as software specifications, which can be translated into computer programs by the routine work of a skilled technician or programmer.

[0158] The computer program includes processor-executable instructions stored on at least one non-transitory, tangible computer-readable medium. The computer program may also include or rely on stored data. The computer program may include a basic input / output system (BIOS) that interacts with the hardware of the special-purpose computer, device drivers that interact with specific devices of the special-purpose computer, one or more operating systems, user applications, background services, background applications, etc.

[0159] A computer program may include: (i) descriptive text to be parsed, such as HTML (Hypertext Markup Language), XML (Extensible Markup Language), or JSON (JS Object Notation), (ii) assembly code, (iii) object code generated by a compiler from source code, (iv) source code executed by an interpreter, (v) source code compiled and executed by a just-in-time compiler, etc. By way of example only, the source code may be written using the syntax of a language including: C, C++, C#, Objective-C, Swift, Haskell, Go, SQL, R, Lisp, Fortran, Perl, Pascal, Curl, OCaml, HTML5 (Hypertext Markup Language Version 5), Ada, ASP (Active Server Pages), PHP (PHP: Hypertext Preprocessor), Scala, Eiffel, Smalltalk, Erlang, Ruby, Visual Lua, MATLAB, SIMULINK, and

Claims

1. A chassis control system for a vehicle, the chassis control system comprising: a first torque source configured to provide torque to a first axle of the vehicle; a second torque source configured to provide torque to a second axle of the vehicle independently of the first torque source; and A vehicle control module configured to control the first torque source and the second torque source to switch between a torque redistribution mode and a torque limiting control mode based on a wheel torque redistribution threshold, a wheel torque limit of at least one of the first and second axles, and a torque limit of one of the first and second torque sources, wherein the torque redistribution mode refers to when torque is selectively provided to the first axle by the first torque source and to the second axle by the second torque source, and wherein the torque limiting control mode refers to when torque to at least one of the first and second axles is limited.

2. The chassis control system according to claim 1, wherein: The vehicle control module is configured to transition from a normal torque shaping mode to a torque increasing mode based on an amount of torque requested by a driver of the vehicle and the wheel torque redistribution threshold; and During the torque increase mode, the vehicle control module increases torque on the first axle and the second axle simultaneously.

3. The chassis control system according to claim 2, wherein: the vehicle control module increasing the torque on the first axle at a first speed and increasing the torque on the second axle at a second speed until the torque on the second axle reaches the wheel torque limit of the second axle, at which time the vehicle control module increases the torque on the first axle at a third speed and increases the torque on the second axle at a fourth speed; The third speed is less than the first speed; and The fourth speed is lower than the second speed.

4. The chassis control system according to claim 3, wherein: the vehicle control module configured to switch from the torque redistribution mode to the torque limiting control mode when the torque on the second axle reaches the wheel torque limit of the second axle, including increasing torque to the first axle at a fifth speed and increasing torque to the second axle at a sixth speed; The fifth speed is less than the third speed; and The sixth speed is lower than the fourth speed.

5. The chassis control system according to claim 4, wherein: The vehicle control module is configured to limit the torque provided to the first axle and avoid increasing torque on the second axle based on a torque limit of the first torque source during operation in the torque limited control mode.

6. The chassis control system according to claim 1, wherein: The vehicle control module is configured to preemptively increase torque to the first axle and to the second axle based on a torque request from a driver of the vehicle.

7. The chassis control system according to claim 6, wherein: the vehicle control module being configured to transition from preemptively increasing torque to the first axle at a first speed and to the second axle at a second speed to operating in a torque increasing mode including increasing torque to the first axle at a third speed and to the second axle at a fourth speed; The third speed is less than the first speed; and The fourth speed is different from the second speed.

8. The chassis control system according to claim 7, wherein: The vehicle control module is configured to transition from the torque increasing mode to a torque speed reducing mode, wherein the torque speed reducing mode includes avoiding adding the torque to the second axle and maintaining an amount of torque on the second axle below a wheel torque limit of the second axle.

9. The chassis control system according to claim 8, wherein: The vehicle control module is configured to transition from the torque redistribution mode to the torque limiting control mode when the torque to the first axle reaches a wheel torque limit of the first axle.

10. A chassis control method, comprising: determining a lateral acceleration of a vehicle, an amount of torque requested by a driver of said vehicle, a speed of said vehicle, and road surface conditions; determining an operating boundary based on the lateral acceleration of the vehicle, the amount of torque requested by the driver of the vehicle, a speed of the vehicle, and the road surface condition; and The first torque source of the first wheel axle of the vehicle and the second torque source of the second wheel axle of the vehicle are controlled to switch between a torque redistribution mode and a torque limiting control mode based on the operating boundary, the wheel torque redistribution threshold, the wheel torque limit of at least one of the first wheel axle and the second wheel axle, and the torque limit of one of the first torque source and the second torque source, wherein the torque redistribution mode refers to when torque is selectively provided to the first wheel axle by the first torque source and to the second wheel axle by the second torque source, and wherein the torque limiting control mode refers to when torque to at least one of the first wheel axle and the second wheel axle is limited.

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