Torque control for vehicles with independent front and rear drive systems

Abstract

A method comprising: - Obtaining data on one or more parameters of a vehicle while the vehicle is being driven, the vehicle having a front axle and a rear axle; and - Transferring torques based on the one or more parameters to the front axle and the rear axle independently of each other, wherein: - the step of obtaining data comprises obtaining data about a current yaw rate and a desired yaw rate for the vehicle; and - the step of transferring torques comprises transferring torques to the front axle and the rear axle independently of one another based on the current yaw rate and the desired yaw rate, and wherein the torques for both the front and rear axles are reduced such that the reduction in torque to the front axle is greater than the reduction in torque to the rear axle when it is determined that the difference between the absolute value of the desired yaw rate minus the absolute value of the current yaw rate is greater than a predetermined threshold, and wherein - if it is determined that the difference between the absolute value of the desired yaw rate minus the absolute value of the current yaw rate is less than or equal to the predetermined threshold, then a determination is made as to whether a difference between the absolute value of the current yaw rate minus the absolute value of the desired yaw rate is greater than a second predetermined threshold, wherein if it is determined that the difference between the absolute value of the current yaw rate minus the absolute value of the desired yaw rate is greater than the predetermined second threshold, then the torques of both the front and rear axles are reduced such that the reduction in torque to the rear axle is greater than the reduction in torque to the front axle.

Description

Technical area

[0001] The present disclosure relates generally to vehicles and, more particularly, to methods and systems for controlling torque for multiple axles of a vehicle. background

[0002] Today, many vehicles control the torques applied to the vehicle's axles, for example, by reducing or increasing torque to help compensate for vehicle understeer or oversteer and / or in various other situations. However, such existing methods can have disadvantages for the overall drive system of the vehicle.

[0003] Accordingly, it is desirable to provide methods for controlling torques for vehicle axles while maintaining, for example, overall propulsion for the vehicle. Furthermore, other desirable features and characteristics of the present invention will become apparent from the following detailed description and the appended claims, taken in conjunction with the accompanying drawings, the foregoing technical field and background.

[0004] US 2014 / 0 297 141 A1 relates to a drive force distribution control device for a four-wheel drive vehicle comprising a basic distribution determining device and a servo controller.

[0005] DE 60 2005 003 617 T2 relates to a control method for a four-wheel drive vehicle.

[0006] DE 10 2011 006 813 A1 relates to a system for distributing drive to the front and rear axles of a vehicle, comprising: a front axle motor coupled to the front axle and a rear axle motor coupled to the rear axle. An electronic control unit (ECU), electronically coupled to the motors, commands the rear axle motor to increase the torque supplied to the rear axle during understeer and commands the front axle motor to increase the torque supplied to the front axle during oversteer.

[0007] DE 10 2009 045 418 A1 relates to a method comprising changing the actual torque acting on the axle by automatic intervention via a vehicle assistance system and increasing or decreasing the target drive torque, which is supplied to the vehicle assistance system as input for the automatic positioning of the drive torque in the drive motors arranged on the axle. Summary

[0008] According to the disclosure, a method having the features of claim 1 is provided.

[0009] According to the disclosure, a system having the features of claim 9 is provided.

[0010] According to another exemplary embodiment, a vehicle is provided. The vehicle includes a body, a front axle, a rear axle, a data unit, and a processor. The front axle and the rear axle are disposed within the body. The data unit is configured to obtain data about one or more vehicle parameters while the vehicle is being driven. The processor is disposed within the body and is coupled to the data unit. The processor is configured to transfer torque or at least facilitate the transfer of torque to the front axle and the rear axle independently of one another based on the one or more parameters. Description of the drawings

[0011] The present disclosure will hereinafter be described in conjunction with the following drawing figures, wherein like numerals indicate like elements and wherein: Fig. 1 is a functional block diagram of a vehicle including a front axle, a rear axle, a front-wheel drive system, a rear-wheel drive system, and a control system that controls torques for the front and rear axles independently using the front and rear-wheel drive systems; Fig. 2 is a flow diagram of a process for transmitting torque for a vehicle, and in connection with the vehicle, including the control system, the front-wheel drive system and the rear-wheel drive system of the Fig. 2, can be used; and Fig. 3 a flowchart of a sub-process for the process of Fig. 2, namely the sub-process of reducing torques on the front and rear axles under certain conditions according to an exemplary embodiment. Detailed description

[0012] The following detailed description is merely exemplary in nature and is not intended to limit the disclosure or the application and uses thereof. Furthermore, there is no intention to be bound by any theory disclosed in the foregoing background or the following description.

[0013] Fig. 1 shows a vehicle 100 or automobile according to an exemplary embodiment. As described in more detail below, the vehicle 100 includes a front axle 102, a rear axle 104 along with a front-wheel drive system 106, a rear-wheel drive system 108, and a control system 110 that independently controls torques to the front and rear axles 102, 104 using the front and rear-wheel drive systems 106, 108. In certain embodiments, the control system 101 includes, is part of, and / or coupled to one or more engine control systems (ECS) and / or safety systems for the vehicle 100 (such as automatic braking, brake boost, steering boost, traction control, electronic stability control, lane departure warning, lane change awareness, and / or one or more other active safety features), among other possible systems.As discussed further below, the control system 110 includes a sensor array 112 and a controller 114, which are used to control the torques for the front and rear axles 102, 104.

[0014] As in Fig. 1, the vehicle 100 also includes a chassis 116, a body 118, a plurality of wheels 126, a steering system 122, and a braking system 124. The body 118 is disposed on the chassis 116 and substantially contains the other components of the vehicle 100. The body 118 and the chassis 116 may together form a frame. The wheels 126 are each rotatably coupled to the chassis 116 near corresponding corners of the body 118. In various embodiments, the vehicle 100 may be different from the vehicle shown in Fig. 1. For example, while four wheels 126 in Fig. 1, the number of wheels 126 may vary in certain embodiments.

[0015] In the exemplary embodiment shown in Fig. 1, both the front-wheel drive system 106 and the rear-wheel drive system 108, which drive the wheels 126, are mounted on the chassis 116. The front-wheel drive system 106 moves the front axle 102 based on instructions provided by the control system 110, and the rear-wheel drive system 108 moves the rear axle 104 based on instructions provided by the control system 110, independently of each other. In various embodiments, the front- and rear-wheel drive systems may include the same type or different types of drive systems, which may include, for example, batteries, electric motors, gas combustion engines, fuel cell engines, and / or various other types of drive systems.

[0016] The steering system 122 is mounted on the chassis 116 and controls the steering of the wheels 126. The steering system 122 includes a steering wheel and a steering column (not shown). The steering wheel receives inputs from a driver of the vehicle 100. The steering column effects desired steering angles for the wheels 126 based on the driver's inputs via the drive shafts of the axles 102, 104.

[0017] The braking system 124 is mounted on the chassis 116 and enables braking of the vehicle 100. The braking system 124 receives inputs from the driver via a brake pedal (not shown) and enables appropriate braking via a brake unit (also not shown). The driver also provides inputs via an accelerator pedal (not shown) for a desired speed or acceleration of the vehicle, as well as various other inputs for various vehicle devices and / or systems, such as one or more vehicle radios, other entertainment systems, environmental control systems, lighting units, navigation systems, and the like (also not shown). Similar to the discussion above regarding possible variations for the vehicle 100, in certain embodiments, steering, braking, and / or acceleration may be controlled by a computer instead of a driver.

[0018] The control system 110 is mounted on the chassis 116. As discussed above, the control system 110 controls the torques of the front and rear axles 102, 104, respectively, via the front and rear drive systems 106, 108 and includes a sensor array 112 and a controller 114.

[0019] The sensor array 112 includes various sensors (referred to herein as sensor units) used to calculate a speed of the vehicle using different methods. In the illustrated embodiment, the sensor array 112 includes one or more wheel sensors 126, steering sensors 128, and yaw sensors 130. In one embodiment, the wheel sensors 126 measure the speed and angle of one or more of the wheels 126 of the vehicle 100. Also, in one embodiment, the steering sensors 128 measure positions and / or movements of a steering wheel of the steering system 122 of the vehicle 100. Additionally, in one embodiment, the yaw sensors 130 measure a yaw rate of the vehicle 100. The measurements and information from the various sensors of the sensor array 112 are provided to the controller 114 for processing.In certain embodiments, the sensor array 112 may include one or more other sensors 132 such as one or more accelerometers (e.g., longitudinal and lateral accelerometers) and / or Global Positioning System (GPS) sensors and / or other sensors.

[0020] The control unit 114 is coupled to the sensor array 112. The control unit 114 uses the various measurements and information from the sensor array 112 to transfer torque to the front and rear axles 102, 104 independently of each other using the front and rear drive systems 106, 108 using various methods. The control unit 114, together with the sensor array 112, also enables additional functions, such as those discussed below and in conjunction with the flowcharts of the process 200, as shown in the Fig. 2 and Fig. 3 and discussed below.

[0021] As in Fig. 1, the control unit 114 includes a computer system. In certain embodiments, the control unit 114 may also include one or more of the sensors of the sensor array 112, one or more other devices and / or systems and / or components thereof. Additionally, it will be appreciated that the control unit 114 may differ in other ways from the embodiment shown in Fig. 1. For example, controller 114 may be coupled to or may otherwise utilize one or more remote computer systems and / or other control systems, such as an electronic control system of vehicle 100.

[0022] In the illustrated embodiment, the computer system of the control unit 114 includes a processor 134, a memory 136, an interface 138, a storage device 140, and a bus 142. The processor 134 performs the computing and control functions of the control unit 114 and may include any type of processor or multiple processors, individual integrated circuits such as a microprocessor, or any suitable number of integrated circuit devices and / or circuit boards that cooperate to complete the functions of a processing unit. During operation, the processor 134 executes one or more programs 144 contained within the memory 136 and thus controls the overall operation of the control unit 114 and the computer system of the control unit 114, generally by executing the processes described herein, such as the process 200 described further below in connection with the Fig. 2 and Fig. 3 is described.

[0023] The memory 136 may be any suitable type of memory. For example, the memory 136 may include various types of dynamic random access memory (DRAM), such as SDRAM, various types of static RAM (SRAM), and various types of non-volatile memory (PROM, EPROM, and Flash). In certain examples, the memory is located on and / or co-located with the same computer chip as the processor 134. In the illustrated embodiment, the memory 136 stores the aforementioned program 144 along with one or more stored values ​​146 (e.g., any stored dynamic models, thresholds, and / or other values) for use in performing the determinations.

[0024] Bus 142 is used to transfer programs, data, status, and other information or signals between the various components of the computer system of controller 114. Interface 138 enables communication with the computer system of controller 114, for example, from a system drive and / or another computer system, and may be performed using any suitable method or device. In one embodiment, interface 138 obtains various data from the sensors of sensor array 112. Interface 138 may include one or more network interfaces to communicate with other systems or components. Interface 138 may also include one or more network interfaces to communicate with technicians and / or one or more storage interfaces to connect storage devices such as storage device 140.

[0025] The storage device 140 may be any suitable type of storage device, including random access storage devices such as hard disks, flash systems, floppy disk drives, and optical disk drives. In an exemplary embodiment, the storage device 140 includes a program product from which the memory 136 can receive a program 144 that executes one or more embodiments of one or more processes of the present disclosure, such as the steps of process 200 (and any sub-processes thereof) described below in connection with the Fig. 2 and Fig. 3. In another exemplary embodiment, the program product may be stored directly in memory 136 and / or on a diskette (e.g., disk 148) and / or accessed in other ways, as referenced below.

[0026] Bus 142 may be any suitable physical or logical means for connecting the computer system and components. This includes, but is not limited to, direct hard-wired connections, fiber optics, infrared, and wireless bus technologies. During operation, program 144 is stored in memory 136 and executed by processor 134.

[0027] It will be appreciated that while this exemplary embodiment is described in the context of a fully functioning computer system, one of ordinary skill in the art will appreciate that the mechanisms of the present disclosure are capable of being distributed as a program product having one or more types of non-transitory computer-readable signal-bearing media used to store the program and instructions thereof and to carry out the distribution thereof, such as a non-transitory computer-readable medium carrying the program and having computer instructions stored therein for causing a computer processor (see processor 135) to execute and perform the program.Such a program product may take a variety of forms, and the present disclosure applies equally without regard to the particular type of computer-readable signal-bearing medium used to effect distribution. Examples of signal-bearing media include recording media such as a floppy disk, a hard disk, memory cards, and optical disks, and transmission media such as digital and analog communication links. It will be appreciated that cloud-based storage and / or other methods may also be used in certain embodiments. Similarly, it will be appreciated that the computer system of controller 114 may differ in other ways from the embodiment shown in FIG. Fig. 1, for example, in that the computer system of the controller 114 may be coupled to or otherwise utilize one or more remote computer systems and / or other control systems.

[0028] While control system 110, sensor array 112, and controller 114 are shown as being part of the same system, it should be appreciated that in certain embodiments, these features may include two or more systems. Additionally, in various embodiments, control system 110 may include and / or be coupled to all or portions of various other vehicle devices and systems, such as, among others, drive systems 106, 108, steering system 122, braking system 124, and / or an engine control system for vehicle 100.

[0029] Fig. 2 is a flowchart of a process 200 for controlling the front and rear axles of a vehicle according to an exemplary embodiment. The process 200 may be used in conjunction with the vehicle 100, including the control system 110, the Fig. 1 according to an exemplary embodiment.

[0030] As in Fig. 2, the process 200 begins with step 202. Once the process is initiated, data is acquired (step 203). In certain embodiments, the data includes measured and / or calculated parameter values ​​including a vehicle speed, as well as a current slip angle (e.g., an estimated or current slip angle), a desired slip angle, a current yaw rate (e.g., an estimated or current yaw rate), and a desired yaw rate for the vehicle.As referred to herein, (i) “slip angle” refers to an angular difference between a direction the vehicle is pointing and a direction of travel of the vehicle; (ii) “actual slip angle” refers to an estimated, calculated, measured and / or current slip angle for the vehicle (in certain embodiments, the current slip angle is estimated using an on-board algorithm based on information from inertial measurement unit (IMU) sensors, vehicle motion and driver inputs - in such an embodiment, the slip angle is nominally estimated by measuring a slip angle rate over time and integrating the slip angle rate); (iii) “desired slip angle” refers to the driver’s intention for the slip angle for the vehicle (e.g.as a function of the vehicle's suspension geometry and vehicle speed); (iv) "yaw rate" refers to an angular rotation of the vehicle over time; (v) "actual yaw rate" refers to a measured, calculated and / or actual yaw rate of the vehicle (e.g., as measured or defined using a yaw rate sensor); and (vi) "desired yaw rate" refers to a driver's intention for the vehicle's yaw rate (e.g., as determined as a function of driver intervention in a vehicle's steering wheel and vehicle speed).

[0031] In certain embodiments, background data is obtained to determine these parameter values ​​in step 203. In one embodiment, these values ​​are provided by a data unit of the vehicle 100 of the Fig. 1 by various sensors of the sensor array 112 of the Fig. 1 and / or are determined and are sent to the control unit 114 of the Fig. 1 (and in particular the processor 134 thereof) for processing. In an exemplary embodiment, the vehicle speed is determined from the wheel speed measurements from the wheel sensors 126 of the Fig. 1, the current slip angle is estimated using an on-board algorithm based on information from sensors of an inertial measurement unit (IMU), the vehicle movement and the driver inputs, the current yaw rate is determined by the yaw sensors 130 of the Fig. 1, the desired slip angle is determined as a function of the vehicle suspension geometry, driver inputs and vehicle speed, and the desired yaw rate is determined from the vehicle speed and the steering sensors 128 of the Fig. 1 and the vehicle speed.

[0032] A determination is made as to whether a vehicle speed is greater than a first threshold (step 204). In one embodiment, the vehicle speed is obtained from step 203. In addition, the first predetermined threshold is stored in the memory 136 of the Fig. 1 in one embodiment stored as one of the stored values ​​146 thereof. In one embodiment, this threshold may be approximately equal to five miles per hour (5 mph). However, this may vary in other embodiments. In one embodiment, step 204 is also performed by the processor 134 of the Fig. 1 carried out.

[0033] In certain embodiments, additional calculations are performed on the data from step 203 (step 206). In particular, the current slip angle, the desired slip angle, and the desired yaw rate are calculated in one embodiment in step 206 assuming that these values ​​were not already determined in step 203. In one embodiment, the calculations of step 206 are performed by the processor 134 of the Fig. 1 carried out.

[0034] Determinations are made as to whether (a) a rate of change of the current slip angle over time is greater than or equal to a second predetermined threshold; and (b) the current slip angle is greater than or equal to the desired slip angle (step 208). In one embodiment, the rate of change of the slip angle over time is measured by one or more sensors. Also, in one embodiment, the second predetermined threshold is stored in the memory 136 of the Fig. 1 as the value of one of the stored values ​​146 thereof. In one embodiment, the threshold may be approximately equal to two or three degrees per second; however, this may vary in other embodiments. In one embodiment, these determinations are also made by the processor 132 of the Fig. 1 carried out.

[0035] If it is determined that both conditions are met at step 208, namely (a) the rate of change of the current slip angle over time is greater than or equal to the second predetermined threshold; and (b) the current slip angle is greater than or equal to the desired slip angle, then both the front axle torque and the rear axle torque are reduced based on the desired yaw rate and the measured rate (step 210). In one embodiment, the torque adjustments for the front and rear drive systems 106, 108 of the Fig. 1 based on instructions executed by the processor 132 of the Fig. 1 are performed. The process then returns to step 206 described above for a new iteration.

[0036] With reference to Fig. 3, a flowchart is provided for step 210 (or sub-process 210) of process 200 according to an exemplary embodiment. According to this embodiment, a determination is made as to whether a difference between the absolute value of the desired yaw rate minus the absolute value of the current yaw rate is greater than a third predetermined threshold (step 302). In one embodiment, the predetermined threshold of step 302 is stored in the memory 136 of the Fig. 1 as one of the stored values ​​164 thereof. In one embodiment, the threshold may be approximately equal to five degrees per second; however, this may vary in other embodiments. Also in one embodiment, the determination at step 302 is made by the processor 134 of the Fig. 1 carried out.

[0037] If it is determined that the difference between the absolute value of the desired yaw rate minus the absolute value of the current yaw rate is greater than the predetermined threshold of step 302, then the torques for both the front and rear axles are reduced such that the reduction in torque to the front axle is greater than the reduction in torque to the rear axle (step 304). In one embodiment, the magnitude of the torques to be reduced on both axles is determined dynamically rather than by a fixed calibration number.In such an embodiment, this may be determined by a lookup table or by a proportional-integral-derivative (PID) controller based on a current slip angle, a desired slip angle, a current yaw rate, a desired yaw rate, a vehicle speed, or other vehicle motion condition, or the like. In one embodiment, the torque adjustments are made based on instructions issued by the processor 134 of the . Fig. 1 the front and rear drive system 106, 108 of the Fig. 1 are provided.

[0038] In contrast, if it is determined in step 302 that the difference between the absolute value of the desired yaw rate minus the absolute value of the current yaw rate is less than or equal to the predetermined threshold of step 302, then a determination is made as to whether a difference between the absolute value of the current yaw rate minus the absolute value of the desired yaw rate is greater than a fourth predetermined threshold (step 306). In one embodiment, the predetermined threshold of step 306 is stored in the memory 136 of the Fig. 1 as one of the stored values ​​146 thereof. In one embodiment, the threshold value of step 306 is less than the threshold value of step 302. In such an embodiment, the threshold value of step 306 is approximately equal to three degrees per second; however, this may vary in other embodiments. In one embodiment, the determination in step 306 by the processor 134 of the Fig. 1 carried out.

[0039] If it is determined that the difference between the absolute value of the current yaw rate minus the absolute value of the desired yaw rate is greater than the predetermined threshold of step 306, then the torques of both the front and rear axles are reduced such that the reduction in torque to the rear axle is greater than the reduction in torque to the front axle (step 308). In one embodiment, the magnitude of the torques to be reduced on both axles is determined dynamically rather than by a fixed calibration number.In such an embodiment, this may be determined by a lookup table or a proportional-integral-derivative (PID) controller based on a current slip angle, a desired slip angle, a current yaw rate, a desired yaw rate, a vehicle speed or other vehicle motion condition, or the like. In one embodiment, the torque adjustments are made based on instructions issued by the processor 134 of the . Fig. 1 the front and rear drive system 106, 108 of the Fig. 1. In one embodiment where the values ​​are calculated by a PID, the command to modify the torque is also decreased as the error term decreases. In one embodiment, the torque adjustments are made based on instructions provided by the processor 134 of the Fig. 1 the front and rear drive system 104, 108 of the Fig. 1 are provided.

[0040] Conversely, if it is determined in step 306 that the difference between the absolute value of the current yaw rate minus the absolute value of the desired yaw rate is less than or equal to the predetermined threshold of step 306, then the torques of both the front and rear axles are reduced so that the reduction in torque to the rear axle is equal to the reduction in torque to the front axle (step 310).

[0041] If returning to step 208 of the Fig. 2 at step 208 it is determined that one or both of the conditions of step 208 are not met; namely, that (a) the rate of change of the current slip angle over time is less than the second predetermined threshold of step 208 and / or (b) the current slip angle is less than the desired slip angle, then a further determination is made as to whether the rate of change of the current slip angle over time is less than or equal to a fifth threshold; and (b) the current slip angle is less than or equal to the desired slip angle (step 212). In one embodiment, the predetermined threshold of step 212 is stored in the memory 136 of the Fig. 1 as one of the stored values ​​146 thereof. In one embodiment, this threshold may be approximately equal to two or three degrees per second (2 or 3 deg / sec). However, this may vary in other embodiments. In one embodiment, the determinations at step 212 are also made by the processor 134 of the Fig. 1 carried out.

[0042] If it is determined that both the conditions of step 212 are met; namely, (a) the rate of change of the current slip angle over time is less than or equal to the predetermined threshold of step 212; and (b) the current slip angle is less than or equal to the desired slip angle, then the process proceeds to step 210 described above. Conversely, if it is determined that either one or both of these conditions of step 212 are not met, then the process instead proceeds to step 214, as described below.

[0043] During step 214, a determination is made as to whether a product of the desired yaw rate multiplied by the current yaw rate is greater than or equal to zero. Alternatively, in one embodiment, the determination at step 214 includes a determination as to whether the desired yaw rate and the current yaw rate have the same sign (namely, positive or negative). In one embodiment, this determination is made by the processor 134 of the Fig. 1 carried out.

[0044] If it is determined in step 214 that the desired yaw rate and the current yaw rate do not have the same sign, the acceleration of both the front and rear axles is reduced (step 216). In one embodiment, both the front and rear axles are reduced by an equal amount of torque. In one embodiment, the amount of torque to be reduced for both axles is determined in a dynamic manner rather than by a fixed calibration number. In such an embodiment, this may be determined by a lookup table or a proportional-integral-derivative (PID) controller based on a current slip angle, a desired slip angle, a current yaw rate, a desired yaw rate, a vehicle speed or other vehicle motion condition, or the like.Also, in one embodiment, the torque adjustments are based on instructions executed by the processor 134 of the . Fig. 1 the front and rear drive system 106, 108 of the Fig. 1 are provided.

[0045] Conversely, if it is determined in step 214 that the desired yaw rate and the current yaw rate have the same sign, then a determination is made as to whether a difference between the absolute value of the desired yaw rate and the absolute value of the current yaw rate is greater than or equal to a sixth predetermined threshold (step 218). In one embodiment, the predetermined threshold of step 218 is stored in the memory 136 of the Fig. 1 as one of the stored values ​​146 thereof. In one embodiment, this threshold may be approximately equal to five degrees per second. However, this may vary in other embodiments. Also in one embodiment, the determination at step 218 is made by the processor 134 of the Fig. 1 carried out.

[0046] If it is determined at step 218 that the difference between the absolute value of the desired yaw rate and the absolute value of the actual yaw rate is greater than or equal to the predetermined threshold of step 218, then the torque to the front axle is reduced while the torque to the rear axle is increased (step 220). In one embodiment, the torque reduction to the front axle is equal to the torque increase to the rear axle, so that the overall torque balance (and therefore the overall propulsion) for the vehicle remains the same. For example, in one embodiment, the magnitude of the propulsion torque will be less than the driver-demanded torque, but the front / rear distribution of the propulsion torque will remain the same (thus maintaining the consistency of the propulsion torque with respect to the driver-demanded torque).In one embodiment, the torque adjustments are made based on instructions executed by the processor 134 of the . Fig. 1 the front and rear wheel drive system 104,106 of the Fig. 1 are provided.

[0047] Conversely, if it is determined in step 218 that the difference between the absolute value of the desired yaw rate and the absolute value of the current yaw rate is less than the predetermined threshold value of step 218, then a determination is made as to whether a difference between the absolute value of the current yaw rate minus the absolute value of the desired yaw rate is greater than or equal to a seventh predetermined threshold value (step 222). In one embodiment, the predetermined threshold value of step 222 is stored in the memory 136 of the Fig. 1 as one of the stored values ​​146 thereof. In one embodiment, the threshold value of step 222 may be equal to the threshold value of step 218. However, this may vary in other embodiments. In one embodiment, the determinations in step 222 are also made by the processor 134 of the Fig. 1 carried out.

[0048] If it is determined in step 222 that the difference between the absolute value of the current yaw rate and the absolute value of the desired yaw rate is greater than or equal to the predetermined threshold of step 222, then the front axle torque is increased while the rear axle torque is reduced (step 224). In one embodiment, the front axle torque increase is equal to the rear axle torque reduction, so that the overall torque balance (and therefore overall propulsion) for the vehicle remains the same. For example, in one embodiment, the magnitude of the propulsion torque will be less than the driver-requested torque, but the front / rear distribution of the propulsion torque will remain the same (thus maintaining the consistency of the propulsion torque with respect to the driver-requested torque).In one embodiment, the torque adjustments are made based on instructions executed by the processor 134 of the . Fig. 1 the front and rear wheel drive system 104,106 of the Fig. 1 are provided.

[0049] Conversely, if it is determined in step 222 that the difference between the absolute value of the desired yaw rate and the absolute value of the current yaw rate is less than the predetermined threshold of step 222, then the process is terminated (step 226).

[0050] Accordingly, process 200 independently controls torques to the front and rear axles of the vehicle based on vehicle parameters including vehicle speed, desired slip angle, current slip angle, current yaw rate, and desired yaw rate for the vehicle. Additionally, in certain embodiments, process 200 provides for adjustments for certain vehicle conditions (e.g., vehicle oversteer and vehicle understeer) by independently adjusting the torques on the front and rear axles in a manner that maintains the overall propulsion of vehicle 100 (or more specifically, that maintains the driver's intended propulsion for the vehicle, as much as possible consistent with maintaining controllability, e.g., as described above in connection with steps 220-224).

[0051] It will be appreciated that the disclosed methods, systems, and vehicles may vary from those shown in the figures and described herein. For example, the vehicle 100, the control system 110, and / or various components thereof may differ from those shown in Fig. 1 and described in connection therewith. In addition, it will be appreciated that certain steps of the process 200 may differ from those described in the Fig. 2 and Fig. 3 and / or described above in connection therewith. It will similarly be appreciated that certain steps of the methods described above may occur simultaneously or in a different sequence than in the Fig. 2 and Fig. 3 and / or described above in connection therewith. Examples

[0052] Example 1. A method comprising: Obtaining data about one or more parameters of a vehicle while the vehicle is being driven, the vehicle having a front axle and a rear axle; and Transferring torque to the front axle and the rear axle independently based on the one or more parameters.

[0053] Example 2. The method of Example 1, wherein the step of transferring torque comprises increasing torque at one of the front axle or the rear axle and decreasing torque at the other of the front axle or the rear axle based on the one or more parameters while maintaining a value of total torque for the vehicle.

[0054] Example 3. The process of Example 1 or Example 2, wherein: the step of obtaining data comprises obtaining data about a current slip angle and a desired slip angle for the vehicle; and the step of transferring torques comprises transferring torques to the front axle and to the rear axle independently of each other based on the current slip angle and the desired slip angle.

[0055] Example 4. The process according to any one of Examples 1 to 3, wherein: the step of obtaining data comprises obtaining data about a current yaw rate and a desired yaw rate for the vehicle; and the step of transferring torques comprises transferring torques to the front axle and the rear axle independently of each other based on the current yaw rate and the desired yaw rate.

[0056] Example 5. The process according to Example 3, wherein the step of transferring torques comprises reducing the torques of both the front axle and the rear axle when a rate of change of the current slip angle is greater than a predetermined threshold and the current slip angle is greater than the desired slip angle.

[0057] Example 6. The process of Example 5, wherein: the step of obtaining data further comprises obtaining data about a current yaw rate and a desired yaw rate for the vehicle; and the step of transmitting torque includes: Reducing the torque of the front axle by a first amount and reducing the torque of the rear axle by a second amount which is smaller than the first amount if an absolute value of the desired yaw rate is greater than an absolute value of the current yaw rate; and Reducing the front axle torque by a third amount and reducing the rear axle torque by a fourth amount greater than the third amount if the absolute value of the current yaw rate is greater than the absolute value of the current yaw rate.

[0058] Example 7. The process of Example 4, wherein: the step of obtaining data comprises obtaining data about a current slip angle and a desired slip angle for the vehicle; and the step of transferring torques comprises reducing the torque to the front axle and increasing the torque to the rear axle when a rate of change of the current slip angle is less than a first predetermined threshold, a product of the desired yaw rate and the current yaw rate is greater than or equal to zero, and a difference between an absolute value of the desired yaw rate and an absolute value of the current yaw rate is greater than a second predetermined threshold.

[0059] Example 8. The process of Example 4, wherein: the step of obtaining data comprises obtaining data about a current slip angle and a desired slip angle for the vehicle; and the step of transmitting torques comprises increasing the torque of the front axle and decreasing the torque of the rear axle when a rate of change of the current slip angle is less than a first predetermined threshold, a product of the desired yaw rate and the current yaw rate is greater than or equal to zero, and a difference between an absolute value of the current yaw rate and an absolute value of the current yaw rate is greater than a second predetermined threshold.

[0060] Example 9. The process of Example 4, wherein: the step of obtaining data comprises obtaining data about a current slip angle and a desired slip angle for the vehicle; and the step of transferring torques comprises reducing the torque of the front axle and reducing the torque of the rear axle when a rate of change of the current slip angle is less than a first predetermined threshold and a product of the desired yaw rate and the current yaw rate is less than zero.

[0061] Example 10. A system comprising: a data unit configured to obtain data about one or more parameters of a vehicle while the vehicle is being driven, the vehicle having a front axle and a rear axle; and a processor coupled to the data unit and configured to transmit torque to facilitate at least transmitting torque to the front axle and the rear axle independently of one another based on the one or more parameters.

[0062] Example 11. The system of Example 10, wherein the processor is configured to at least enable: increasing the torque on one of the front axle or the rear axle and decreasing the torque on the other of the front axle or the rear axle based on the one or more parameters while maintaining consistency between the total torque and a driver-requested torque for the vehicle.

[0063] Example 12. The system of Example 10 or Example 11, wherein: the data unit is configured to obtain a speed of the vehicle; and the processor is configured to facilitate at least transferring torque to the front axle and the rear axle independently of one another based on the one or more parameters if the speed is less than a predetermined threshold.

[0064] Example 13. The system of Example 10, where: the data unit is configured to obtain data on a current slip angle and a desired slip angle for the vehicle; and the processor is configured to facilitate at least a transfer of torque to the front axle and the rear axle independently of one another based on the current slip angle and the desired slip angle.

[0065] Example 14. The system of Example 10, where: the data unit is configured to obtain data about a current yaw rate and a desired yaw rate for the vehicle; and the processor is configured to facilitate at least transferring torque to the front axle and the rear axle independently of one another based on the current yaw rate and the desired yaw rate.

[0066] Example 15. The system of example 13, wherein the processor is configured to facilitate at least the following: reducing a torque for both the front axle and the rear axle when a rate of change of the current slip angle is greater than a predetermined threshold and the current slip angle is greater than the desired slip angle.

[0067] Example 16. The system of Example 15, where: the data unit is configured to obtain data about a current yaw rate and a desired yaw rate for the vehicle; and the processor is configured to facilitate at least the following: reducing a torque on the front axle by a first amount and reducing the torque of the rear axle by a second amount, which is smaller than the first amount, if an absolute value of the desired yaw rate is greater than an absolute value of the current yaw rate; and reducing the torque to the front axle by a third amount and reducing the torque to the rear axle by a fourth amount, which is greater than the third amount, if the absolute value of the current yaw rate is greater than the absolute value of the current yaw rate.

[0068] Example 17. The system of Example 14, where: the data unit is configured to obtain data from a current slip angle and a desired slip angle for the vehicle; and the processor is configured to facilitate at least reducing a torque to the front axle and increasing the torque to the rear axle when a rate of change of the current slip angle is less than a first predetermined threshold, a product of the desired yaw rate and the current yaw rate is greater than or equal to zero, and a difference between an absolute value of the desired yaw rate and an absolute value of the current yaw rate is greater than a second predetermined threshold.

[0069] Example 18. The system of Example 14, where: the data unit is configured to obtain data on a current slip angle and a desired slip angle for the vehicle; and the processor is configured to facilitate at least increasing the torque of the front axle and decreasing the torque of the rear axle when a rate of change of the current slip angle is less than a first predetermined threshold, a product of the desired yaw rate and the current yaw rate is greater than or equal to zero, and a difference between an absolute value of the current yaw rate and an absolute value of the current yaw rate is greater than a second predetermined threshold.

[0070] Example 19. The system of Example 14, where: the data unit is configured to obtain data on a current slip angle and a desired slip angle for the vehicle; and the processor is configured to enable at least reducing a torque of the front axle and reducing the torque of the rear axle when a rate of change of the current slip angle is less than a predetermined threshold and a product of the desired yaw rate and the current yaw rate is less than zero.

[0071] Example 20. A vehicle comprising: a body; a front axle which is arranged within the body; a rear axle located within the body; a data unit configured to obtain data about one or more vehicle parameters while the vehicle is moving; and a processor disposed within the body and coupled to the data unit, the processor configured to transmit torque to facilitate at least transmitting torque to the front axle and the rear axle independently of one another based on the one or more parameters.

[0072] While at least one exemplary embodiment has been presented in the foregoing detailed description, it should be appreciated that numerous variations exist. It should also be understood that the exemplary embodiment or embodiments are merely examples and are not intended to limit the scope, applicability, or configurations of the disclosure in any way. Rather, the foregoing detailed description will provide those skilled in the art with a convenient road map for implementing the exemplary embodiment or embodiments. It should be understood that various changes in the function and arrangement of elements may be made without departing from the scope of the appended claims and the legal equivalents thereof.

Claims

[1] A method comprising: - Obtaining data on one or more parameters of a vehicle while the vehicle is being driven, the vehicle having a front axle and a rear axle; and - Transferring torques based on the one or more parameters to the front axle and the rear axle independently of each other, wherein: - the step of obtaining data comprises obtaining data about a current yaw rate and a desired yaw rate for the vehicle; and - the step of transferring torques comprises transferring torques to the front axle and the rear axle independently of one another based on the current yaw rate and the desired yaw rate, and wherein the torques for both the front and rear axles are reduced such that the reduction in torque to the front axle is greater than the reduction in torque to the rear axle when it is determined that the difference between the absolute value of the desired yaw rate minus the absolute value of the current yaw rate is greater than a predetermined threshold, and wherein - if it is determined that the difference between the absolute value of the desired yaw rate minus the absolute value of the current yaw rate is less than or equal to the predetermined threshold, then a determination is made as to whether a difference between the absolute value of the current yaw rate minus the absolute value of the desired yaw rate is greater than a second predetermined threshold, wherein if it is determined that the difference between the absolute value of the current yaw rate minus the absolute value of the desired yaw rate is greater than the predetermined second threshold, then the torques of both the front and rear axles are reduced such that the reduction in torque to the rear axle is greater than the reduction in torque to the front axle. [2] The method of claim 1, wherein the step of transferring torque based on the one or more parameters comprises increasing the torque to one of the front axle or the rear axle and decreasing the torque to the other of the front axle or the rear axle while maintaining a value of total torque for the vehicle. [3] The method of claim 1, wherein: - the step of obtaining data comprises obtaining data about a current slip angle and a desired slip angle for the vehicle; and - the step of transferring torques comprises transferring torques to the front axle and to the rear axle independently of each other based on the current slip angle and the desired slip angle. [4] The method of claim 3, wherein the step of transferring torque comprises reducing the torque of both the front axle and the rear axle when a rate of change of the current slip angle is greater than a predetermined threshold and the current slip angle is greater than the desired slip angle. [5] The method of claim 4, wherein: - the step of obtaining data further comprises obtaining data about a current yaw rate and a desired yaw rate for the vehicle; and - the torque transmission step includes: - reducing the torque of the front axle by a first amount and reducing the torque of the rear axle by a second amount which is smaller than the first amount if an absolute value of the desired yaw rate is greater than an absolute value of the current yaw rate; and - Reducing the front axle torque by a third amount and reducing the rear axle torque by a fourth amount which is greater than the third amount if the absolute value of the current yaw rate is greater than the absolute value of the desired yaw rate. [6] The method of claim 1, wherein: - the step of obtaining data comprises obtaining data about a current slip angle and a desired slip angle for the vehicle; and - the step of transmitting torques comprises reducing the torque to the front axle and increasing the torque to the rear axle when a rate of change of the current slip angle is less than a first predetermined threshold, a product of the desired yaw rate and the current yaw rate is greater than or equal to zero, and a difference between an absolute value of the desired yaw rate and an absolute value of the current yaw rate is greater than a second predetermined threshold. [7] The method of claim 1, wherein: - the step of obtaining data comprises obtaining data about a current slip angle and a desired slip angle for the vehicle; and - the step of transmitting torques comprises increasing the torque to the front axle and decreasing the torque to the rear axle when a rate of change of the current slip angle is less than a first predetermined threshold, a product of the desired yaw rate and the current yaw rate is greater than or equal to zero, and a difference between an absolute value of the current yaw rate and an absolute value of the desired yaw rate is greater than a second predetermined threshold. [8] The method of claim 1, wherein: - the step of obtaining data comprises obtaining data about a current slip angle and a desired slip angle for the vehicle; and - the step of transferring torques comprises reducing the torque to the front axle and reducing the torque to the rear axle when a rate of change of the current slip angle is less than a first predetermined threshold and a product of the desired yaw rate and the current yaw rate is less than zero. [9] A system comprising: - a data unit configured to obtain data about one or more parameters of a vehicle while the vehicle is being driven, the vehicle having a front axle and a rear axle; and - a processor coupled to the data unit and configured to transmit torques based on the one or more parameters to facilitate at least transmitting torques to the front axle and to the rear axle independently of each other, wherein: - the step of obtaining data comprises obtaining data about a current yaw rate and a desired yaw rate for the vehicle; and - the step of transferring torques comprises transferring torques to the front axle and the rear axle independently of one another based on the current yaw rate and the desired yaw rate, and wherein the torques for both the front and rear axles are reduced such that the reduction in torque to the front axle is greater than the reduction in torque to the rear axle when it is determined that the difference between the absolute value of the desired yaw rate minus the absolute value of the current yaw rate is greater than a predetermined threshold, and wherein - if it is determined that the difference between the absolute value of the desired yaw rate minus the absolute value of the current yaw rate is less than or equal to the predetermined threshold, then a determination is made as to whether a difference between the absolute value of the current yaw rate minus the absolute value of the desired yaw rate is greater than a second predetermined threshold, wherein if it is determined that the difference between the absolute value of the current yaw rate minus the absolute value of the desired yaw rate is greater than the predetermined second threshold, then the torques of both the front and rear axles are reduced such that the reduction in torque to the rear axle is greater than the reduction in torque to the front axle.

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