System and method for controlling speed difference of wheels of a vehicle

Abstract

Systems and methods for controlling a speed differential of wheels of a vehicle are provided herein. The vehicle determines a wheel steering angle, where the wheel steering angle corresponds to a center of rotation of the vehicle. The vehicle determines a differential wheel speed associated with a first wheel of the vehicle and a second wheel of the vehicle based at least on the wheel steering angle. The vehicle independently applies a torque to the first wheel and the second wheel based on the differential wheel speed.

Description

Background Technology

[0001] Advantageously, a locking differential ensures that each wheel receives the maximum torque / power from the vehicle's motor, depending on surface conditions; however, due to the powertrain engagement, a locked differential can impede the vehicle's cornering response, as two or all four drive wheels are locked together and cannot rotate at any varying speed. For example, when cornering, a vehicle with a locking differential causes each wheel to travel at the same speed, thus creating resistance to steering input.

[0002] On the other hand, in response to a locking differential, a vehicle traveling on a very low-friction surface experiences reduced stability due to excessive wheel slip, thereby decreasing lateral acceleration potential. Therefore, what is needed is improved cornering capability that allows the vehicle to utilize controlled speed differences at each wheel to follow the vehicle's cornering path. Summary of the Invention

[0003] Therefore, in some embodiments, it is advantageous to provide a system that controls the speed difference between the wheels of a vehicle and adjusts the torque on the wheels to reduce resistance to steering input. Additionally, in some embodiments, it is advantageous to provide a system that determines speed targets for the wheels of a vehicle and adjusts the torque on the wheels to provide stability while driving, thereby limiting or preventing wheel slippage during cornering.

[0004] According to this disclosure, a method for controlling speed differences using control circuitry and a vehicle including control circuitry for controlling speed differences are provided. The speed difference method controls the speed difference between the wheels of a vehicle to improve the vehicle's cornering operation. The control circuitry determines the wheel steering angles of the vehicle. The wheel steering angles affect the vehicle's center of rotation (e.g., based on the vehicle's geometry). The control circuitry determines the differential wheel speeds between a first wheel and a second wheel of the vehicle based on the wheel steering angles. The first and second wheels are at different distances from the center of rotation defined by the wheel steering angles. The control circuitry independently applies torque to the first and second wheels based on the differential wheel speeds. By independently applying torque to the first and second wheels, improved cornering ability is achieved, the vehicle maintains the desired driving path, and resistance to steering input can be limited or prevented. That is, the vehicle maintains its speed while the individual wheel speeds of the wheels change based on the vehicle's geometry (e.g., wheelbase, vehicle trajectory, and tire rotation angles). Furthermore, this disclosure performs speed control for each wheel based on the differential wheel speeds and steering angles. When driving the vehicle in a straight line, the vehicle can transition from and to speed control. The vehicle can maintain the same speed between transitions, and when in speed control mode, the speed can be adjusted up and down based on the accelerator pedal input.

[0005] In some embodiments, the control circuit determines the differential wheel speed by determining a first target wheel speed of the first wheel and a second target wheel speed of the second wheel. In some embodiments, the control circuit determines the first and second target wheel speeds based on one or more of the following: 1) wheel steering angle, 2) center of rotation, 3) distance of the first wheel from the center of rotation, 4) distance of the second wheel from the center of rotation, and / or 5) vehicle speed. In some embodiments, the control circuit applies torque independently to the first and second wheels by applying a first torque to the first wheel to achieve the first target wheel speed and applying a second torque to the second wheel to achieve the second target wheel speed. In some embodiments, the first torque and the second torque are different.

[0006] In some embodiments, the vehicle may include a first motor configured to provide a first torque to a first wheel and coupled to control circuitry. In some embodiments, the vehicle may also include a second motor configured to provide a second torque to a second wheel and coupled to control circuitry. In some embodiments, the first motor and the second motor are different.

[0007] In some embodiments, the vehicle may include four wheels. These four wheels may include a first wheel, a second wheel, a third wheel, and a fourth wheel. In some aspects of this disclosure, the control circuitry can determine the differential wheel speed by determining the differential wheel speed among these four wheels. In some embodiments, the control circuitry determines the differential wheel speed by determining a corresponding target wheel speed for each of the first, second, third, and fourth wheels. In some embodiments, the control circuitry can apply torque independently by applying torque independently to each of the four wheels based on the differential wheel speed. In some embodiments, the control circuitry can apply torque independently by applying torque independently to each of the four wheels based on a corresponding target wheel speed.

[0008] In some embodiments, the vehicle may include four motors, each configured to independently provide torque to a corresponding wheel. In some embodiments, these four motors may be configured to independently provide torque to a corresponding wheel based on a corresponding target wheel speed. Each of the four motors may be coupled to a corresponding motor shaft, which is configured to provide torque / power to each corresponding wheel.

[0009] In some embodiments, each of the four motors in the vehicle may include an electric motor. Each electric motor may include a motor shaft configured to provide torque / power to each corresponding wheel. In some embodiments, the control circuitry may determine the differential wheel speeds among the four wheels by determining a first target wheel speed of the first wheel, a second target wheel speed of the second wheel, a third target wheel speed of the third wheel, and a fourth target wheel speed of the fourth wheel. In some embodiments, the control circuitry may monitor signals from sensors coupled to the motor shafts of the four electric motors. Each sensor may indicate the amount of rotation of the corresponding motor shaft. In some embodiments, the control circuitry may calculate the corresponding wheel speed of each corresponding wheel based on the corresponding signal in the monitored signals. In response to the calculated corresponding wheel speed of each corresponding wheel, the control circuitry may adjust the torque to each corresponding wheel to achieve the corresponding target wheel speed.

[0010] In some implementations, the control circuitry may receive accelerator pedal input to determine the target vehicle speed. In some implementations, the control circuitry system may determine the differential wheel speed by determining the differential wheel speed between the first and second wheels of the vehicle based on the target vehicle speed and the wheel steering angle.

[0011] In some embodiments, the first wheel of the vehicle is positioned at the front of the vehicle on a first side, and the second wheel of the vehicle is positioned at the rear of the vehicle on a second side. The first side of the vehicle may be located on the opposite side of the second side. In some embodiments, the control circuitry may identify the turning direction based on the wheel steering angle. In response to identifying a right turn direction (where the first side of the vehicle is the right side of the vehicle), the control circuitry may adjust the differential wheel speed between the first and second wheels of the vehicle to up to 80% based on the wheel steering angle. In response to identifying a left turn direction (where the first side of the vehicle is the right side of the vehicle), the control circuitry may adjust the differential wheel speed between the first and second wheels of the vehicle to up to 15% based on the wheel steering angle.

[0012] In some embodiments, the control circuitry determines the wheel steering angle by determining that the vehicle's wheel steering angle exceeds a first wheel steering angle threshold. In some embodiments, the control circuitry applies torque independently to the first and second wheels by applying a first torque to the first wheel based on the wheel steering angle exceeding the first wheel steering angle threshold and applying a second torque to the second wheel based on the same threshold. In some embodiments, the first torque and the second torque are different. The control circuitry may also determine that the vehicle's wheel steering angle exceeds a second wheel steering angle threshold. In some embodiments, the control circuitry may provide an overcompensated cornering factor to the first and second wheels based on the second wheel steering angle exceeding the second wheel steering angle threshold.

[0013] In some implementations, the control circuitry may determine the turning path of each wheel of the vehicle based on the wheel steering angle. The turning path of the vehicle affects the travel path of each wheel in the vehicle. In some implementations, the control circuitry may adjust the differential wheel speed of each corresponding wheel in the vehicle based on the determined corresponding turning path. Differential control of speeds can be performed in the various vehicles described herein that are capable of distributing torque and / or braking to each of one or more wheels of the vehicle.

[0014] In some implementations, the vehicle includes an independent four-motor drive system. In some implementations, the vehicle employs controlled speed differentials to avoid locking the wheel differentials, including "locking wheel speeds" to maximize traction. In some implementations, the vehicle uses input from steering wheel angle sensors to determine the ideal speed for each wheel based on the corner or path radius (from 0% wheel speed difference when turning in a straight line to nearly 80% speed difference when turning with full lock). This aspect of the implementation allows for adjusting the motor speed target (motor / wheel / vehicle speed control based on accelerator pedal position rather than the requested torque output) when operating in climb mode to maintain a target vehicle speed while each wheel is at an optimized wheel speed to maximize both traction and operator control and follow the ideal path at any steering angle. In some implementations, the vehicle may additionally increase maneuverability by under-actuating one or two inner wheels relative to their ideal speed target to further enhance vehicle cornering, thus mimicking the function of a cutting brake.

[0015] In some implementations, the control method utilizes an independent four-motor powertrain to overcome the inherent drawbacks of typical limited-slip and mechanically locking differentials (i.e., resistance to vehicle yaw / cornering response to steering input). In some implementations, the vehicle is operated in "climb" mode or any other mode, where the driver's accelerator pedal request is effectively translated into wheel / vehicle speed to enhance controllability, specifically by using input from steering angle sensors to individually adjust each wheel. Based on the driver's intended path, wheel speeds can be controlled to achieve an appropriate speed "difference" not only from the inner wheel to the outer wheel but also from the front wheel to the rear wheel. In some implementations, the first side of the vehicle is the left side, and the second side is the right side. In some implementations, as the steering angle increases, each tire needs to follow an increasingly "different" path diameter and wheel speed. In some implementations, controlling this speed difference generates maximum potential traction and driving force, as well as maintaining the operator's desired driving path. In some implementations, the speed difference can be controlled by “overdrive” by increasing the speed of the outer wheel (or decreasing the speed of the inner wheel or both) to induce additional yaw through additional torque vectoring of the outer wheel or reverse torque vectoring of the inner wheel; mimicking the function of a manual “cut-off brake”; the final or ultimate version of this approach becomes virtually equivalent to zero turning radius (or tank turn).

[0016] In some implementations, the techniques described below may be executed by the vehicle's processing circuitry. The processing circuitry may be implemented as part of the vehicle, included in the vehicle, and / or embedded in vehicle electronics, among other possibilities. In some embodiments, the processing circuitry may include an onboard vehicle computer capable of controlling multiple features or capabilities of the vehicle. In some embodiments, the processing circuitry may be communicatively connected to user inputs to the vehicle, vehicle sensors, and transient or non-transitory memory (e.g., memory storing mechanisms for operating the vehicle). Attached Figure Description

[0017] The present disclosure is described in detail with reference to the following accompanying drawings, which illustrate one or more various embodiments. The drawings are provided for illustrative purposes only and show only typical or exemplary embodiments. These drawings are provided to facilitate understanding of the concepts disclosed herein and should not be considered as limitations on the breadth, scope, or applicability of these concepts. It should be noted that these drawings are not necessarily drawn to scale for clarity and ease of illustration.

[0018] Figure 1 A system diagram of an exemplary vehicle, including processing circuitry, input variables, sensors, and output variables, is depicted according to some embodiments of the present disclosure.

[0019] Figure 2A top cross-sectional view of an exemplary vehicle according to some embodiments of the present disclosure is shown;

[0020] Figure 3 Another top sectional view of an exemplary vehicle according to some embodiments of the present disclosure is shown, in which the turning path of each wheel is shown;

[0021] Figure 4 An illustrative example of the interior of a vehicle, characterized by a graphical user interface, accelerator pedal input, and steering wheel input, is depicted according to some embodiments of the present disclosure.

[0022] Figure 5 Examples of steering wheel inputs for participating in differential speed control according to some embodiments of this disclosure are depicted;

[0023] Figure 6 An exemplary flowchart depicts a process for controlling the speed difference of the wheels of a vehicle by setting the differential speed of the wheels, according to some embodiments of the present disclosure.

[0024] Figure 7 An exemplary flowchart depicts a process for controlling the speed difference between the wheels of a vehicle by setting a target wheel speed, according to some embodiments of the present disclosure; and

[0025] Figure 8 An exemplary flowchart is shown, according to some embodiments of the present disclosure, of a process for controlling the speed difference of the wheels of a vehicle by independently monitoring the wheel speed of each wheel, setting a target wheel speed, and adjusting torque. Detailed Implementation

[0026] Figure 1 A system diagram of an exemplary vehicle 100 according to several embodiments of the present disclosure is depicted. The exemplary vehicle includes processing circuitry 122, input variables 102, 104, 105, sensors 111 to 121, a motor / brake controller 124, and output variables 126 to 132. The exemplary processing circuitry 122 includes a processor 108 and a memory 110.

[0027] Processing circuitry 122 may include hardware, software, or both implemented on one or more modules configured to provide control over the front and rear wheels of a vehicle. In some embodiments, processor 108 includes one or more microprocessors, microcontrollers, digital signal processors, programmable logic devices, field-programmable gate arrays (FPGAs), application-specific integrated circuits (ASICs), or any suitable combination thereof. In some embodiments, processor 108 is distributed across more than one processor or processing unit. In some embodiments, processing circuitry 122 executes instructions stored in memory for managing a four-wheeled vehicle 300 or a three-wheeled vehicle. In some embodiments, memory 110 is an electronic storage device that is part of processing circuitry 122. For example, memory 110 may be configured to store electronic data, computer instructions, applications, firmware, or any other suitable information. In some embodiments, memory 110 includes random access memory, read-only memory, hard disk drives, optical disk drives, solid-state devices, or any other suitable memory storage device, or any combination thereof. For example, memory may be used to initiate startup routines.

[0028] In some embodiments, the system may include at least the following non-limiting inputs, including steering input 102, accelerator pedal input 104, and display input 105. In some embodiments, steering input 102 may be configured to provide input for turning the steerable wheels. For example, the steering input may cause control circuitry to determine the wheel steering angle of the vehicle. The wheel steering angle affects the center of rotation of the vehicle along its travel path (e.g., based on the vehicle's geometry). In some embodiments, accelerator pedal input 104 may be configured to provide throttle input to one or more of the wheels 126, 128, 130, 132 of the vehicle 100. For example, the accelerator pedal input may be transmitted to one or more motors to provide torque to one or more of the wheels 126, 128, 130, 132. For example, when the accelerator pedal is pressed and accelerator pedal input is received. This causes torque to be generated at the wheels, thereby accelerating the vehicle to a speed such that the torque balances the total resistance of the vehicle. In some embodiments, the vehicle may have two motors, one on each side of the vehicle (e.g., left and right), so that the torque is approximately the same for each wheel. In some embodiments, the input interface 105 (e.g., a graphical user interface) may be configured to receive and output vehicle-related information, including the driving path and differential wheel speeds. In some embodiments, the input interface is configured to receive input from the vehicle operator to participate in differential speed control and indicate yaw direction. In some embodiments, the input for participating in differential speed control may engage with the input interface 105 or be another button, paddle shifter, or any other means.

[0029] In some embodiments, the system may include an obstacle detection sensor 111, a wheel rotation sensor 112, a vehicle yaw sensor 114, an orientation sensor 116, a speed sensor 118, an accelerometer sensor 120, and a steering wheel sensor 121. In some embodiments, processing circuitry 122 may be communicatively connected to one or more obstacle detection sensors 111 to monitor obstacles around the vehicle. In some embodiments, processing circuitry 122 may be communicatively connected to one or more wheel rotation sensors 112 (e.g., a resolver) that provide data indicating the wheel rotation (i.e., how fast the wheels of the vehicle are rotating) of each of the vehicle's wheels 126, 128, 130, 132. In some embodiments, processing circuitry 122 may be communicatively connected to one or more steering wheel angle sensors 121 that provide data indicating the steering column of the vehicle 200 to determine the steering angles of the steerable wheels 126 and 128. In some embodiments, when determining the wheel steering angles of the vehicle, control circuitry determines the turning path of each wheel based on its corresponding distance from the vehicle's center of rotation. In some embodiments, the surface friction beneath each wheel may be different, wherein the torque applied to each wheel to achieve the speed difference can vary dynamically. In some embodiments, based on data provided by wheel rotation sensors 112, processing circuitry 122 may determine whether a wheel slips during cornering, and in response, may adjust the applied torque for wheel slip based on the wheel being on a low-friction surface. In some embodiments, processing circuitry 122 may be communicatively connected to one or more vehicle yaw sensors 114, which provide data indicating vehicle rotation. In some embodiments, processing circuitry 122 may be communicatively connected to one or more orientation sensors 116, which provide data indicating the orientation of vehicle 200 in 3D space. For example, orientation sensors 116 may provide data indicating the pitch angle, yaw angle, and roll angle of vehicle 200. In some embodiments, vehicle yaw or yaw rate may be determined by one or more orientation sensors 116. In some embodiments, vehicle yaw or yaw rate may be determined by steering wheel input 102. Orientation sensor 116 can provide data indicating the orientation of vehicle 200. Yaw rate can be determined by calculating the change in orientation over time. In some embodiments, processing circuitry 122 can be communicatively connected to speed sensor 118, which provides the current speed of vehicle 200. In some embodiments, processing circuitry 122 can be communicatively connected to accelerometer sensor 120, which provides the current acceleration of vehicle 200.In some embodiments, processing circuitry 122 may be communicatively connected to steering wheel angle sensor 121, which determines the wheel steering angles of the steerable wheels (e.g., 126 and 128) of vehicle 200. In some embodiments, in response to determining the wheel steering angles of the steerable wheels using steering wheel sensor 121, processing circuitry 122 may determine the turning path of each wheel of the vehicle. Based on the determined turning paths of the vehicle's wheels, control circuitry may determine the differential wheel speeds of the vehicle's wheels. For example, the first wheel may have a wheel speed 40% higher than the second wheel. In some embodiments, the determined wheel steering angles may be compared to a threshold angle (e.g., 10 degrees) to participate in differential speed control. In some embodiments, without participating in differential speed control and in response to a determined wheel steering angle exceeding a threshold angle, processing circuitry 122 may independently apply torque to the wheels to improve stability when driving on very low friction surfaces, thereby preventing excessive wheel slip. In some implementations, in response to participating differential wheel speeds, vehicle 100 may automatically apply torque to the vehicle's wheels based on the steering wheel angle (e.g., without receiving additional input from the accelerator pedal). In some implementations, if the vehicle's target speed is 50 mph but the steering wheel angle is too large to achieve that target speed, the target wheel speed is gradually increased as the steering wheel angle is normalized to subsequently achieve the target speed. In some implementations, the control circuitry adjusts the torque to the vehicle's wheels without participating in differential speed control. For example, when the vehicle receives accelerator pedal input and is traveling at 5 miles per hour (mph), the vehicle operator turns the steering wheel, creating a 20-degree steering wheel angle, and in response, the control circuitry automatically and independently adjusts the torque to each wheel without receiving any new accelerator pedal input.

[0030] Figure 1 The exemplary system diagram 100 can be used to execute separately Figure 6 , Figure 7 and Figure 8 Any or all of the exemplary steps in processes 600, 700, and 800. Figure 1 The exemplary system 100 can be used to control according to this disclosure Figure 2 Either of the wheel / motor configurations shown. In some implementations, not... Figure 1 All components shown need to be included in vehicle 200.

[0031] Figure 2 A top view of an exemplary vehicle 200 according to some embodiments of the present disclosure is shown. In some embodiments, vehicle 200 may be a two-door sedan, a four-door sedan, a truck, a sports utility vehicle, a van, a large truck, a small van, a bus, or any other type of vehicle.

[0032] In some embodiments, vehicle 200 may include a left front wheel 202, a right front wheel 204, a left rear wheel 206, and a right rear wheel 208. In some embodiments, vehicle 200 may include a motor 212. Motor 212 may be connected to the left front wheel 202 (e.g., via a belt, chain, gear, or any other connecting device). Vehicle 200 may also include motors 214, 216, and 218, respectively, which are similarly connected to wheels 204, 206, and 208. In some embodiments, motors 212, 214, 216, and 218 may be configured to provide forward or rearward torque to their respective wheels 202, 204, 206, and 208. In some embodiments, each of motors 212, 214, 216, and 218 may be a different motor. For example, a first motor 212 may be different from a second motor 216. In some embodiments, vehicle 200 may include an accelerator pedal 213 configured to provide accelerator pedal input to vehicle dynamics controller 211, which is configured to convert the accelerator pedal input into torque or a target wheel speed. In some embodiments, vehicle 200 may include a steering wheel 215 configured to provide a steering wheel angle to vehicle dynamics controller 211, which is configured to convert the wheel steering angle into vehicle turning. In some embodiments, vehicle 200 may include a resolver 242 attached to motor 212 and configured to monitor signals from resolver 242 and transmit those signals to vehicle dynamics controller 211. Furthermore, vehicle dynamics controller 211 communicates via corresponding communication lines (232, 234, 236, 238) with each resolver 242, 244, 246, 248 coupled to each motor (212, 214, 216, 218).

[0033] In some embodiments, motors 212, 214, 216, and 218 can be any type of motor capable of generating power (e.g., gas engine, gasoline-electric hybrid motor, electric motor, battery-powered electric motor, hydrogen fuel cell motor). In some embodiments, motors 212, 214, 216, and 218 can be battery-powered electric motors configured for driving and propulsion of a vehicle, specifically by utilizing multiple battery cells packaged together to form one or more battery modules or components to store energy and release that energy on demand. In some embodiments, motors 212, 214, 216, and 218 can be devices connected to a primary single motor (not shown) and configured to independently transmit power from the single motor to wheels 202, 204, 206, and 208. For example, motors 212, 214, 216, and 218 can independently transmit power to wheels 202, 204, 206, and 208, causing wheels 202, 204, 206, and 208 to rotate at different speeds in one direction (e.g., forward), thereby enabling vehicle 200 to reduce resistance to steering input and provide stability when driving on extremely low friction surfaces to prevent excessive wheel slip. In some embodiments, the vehicle may include four motors 212, 214, 216, and 218, each configured to independently provide torque to the corresponding wheels 202, 204, 206, and 208. In some embodiments, these four motors 212, 214, 216, and 218 may be configured to independently provide torque to the corresponding wheels 202, 204, 206, and 208 based on the corresponding target wheel speed. In some embodiments, the first torque provided to the first wheel is different from the second torque provided to the second wheel.

[0034] In some embodiments, vehicle 200 may include processing circuitry 122. In some embodiments, processing circuitry 122 may include an onboard vehicle computer capable of controlling multiple features or capabilities of the vehicle. In some embodiments, processing circuitry 122 may be communicatively connected to user inputs of vehicle 200 (e.g., graphical user interface 402), vehicle sensors, and transient or non-transitory memory (e.g., memory storing instructions for operating the vehicle).

[0035] In some embodiments, vehicle 200 may include multiple sensors. For example, some of these multiple sensors may include a vehicle rotation sensor 114 for determining the speed of vehicle 200, the wheel steering angle to which the front wheels 202, 204 of vehicle 200 are turned, a vehicle rotation sensor 114 for determining the rotation of the vehicle in vehicle yaw mode, a wheel rotation sensor 112 (e.g., resolver 242, 244, 246, 248) for determining the wheel speed of each of the wheels 202, 204, 206, and 208 of vehicle 200, and an accelerometer sensor 120.

[0036] In some implementations, the processing circuitry 122 of vehicle 200 may be able to directly control features of vehicle 200 with or without user input. In one example, the processing circuitry 122 may be able to actuate motor 212 to provide a specified amount of forward torque to the left front wheel 202, thereby achieving a target wheel speed. Similarly, the processing circuitry 122 may be able to actuate any of motors 214, 216, 218 to provide a specified amount of rearward or forward torque to wheels 204, 206, 208, respectively, thereby achieving a target wheel speed.

[0037] In some embodiments, the left front wheel 202 and the right front wheel 204 may be connected via a drive shaft (not shown). Figure 2 As shown, the vehicle is positioned such that each wheel is at a different distance from the vehicle’s rotation center 201, which defines the center of the concentric circles of the vehicle’s exemplary turning. Figure 2 A vehicle 200 is depicted performing a right turn by providing steering through the front wheels 202 and 204. In some embodiments, the left front wheel 202 receives forward torque based on a lookup table indicating the percentage difference between the left front wheel 202 and the right rear wheel 208. However, those skilled in the art will recognize that similar techniques can be used to perform any turning or movement, including all wheels receiving torque in the same direction. In some embodiments, when the vehicle 200 travels in a straight line, the entire vehicle travels at the same speed. On the other hand, when the vehicle 200 turns (e.g., receives steering wheel input), different locations on the vehicle (e.g., wheels 202, 204, 206, 208) will travel at different speeds based on their distance from the center of rotation 201 of the turn. In some embodiments, the differential wheel speeds are referenced to the vehicle speed. Table 1, reproduced below, shows data on the differential wheel speeds between the first and second wheels based on different steering wheel angles. In this illustrative example, the first and second wheels are located on opposite sides of the vehicle. For example, the first wheel is the left front wheel 202, and the second wheel is the right rear wheel 208. It should be noted that Table 1 is provided for illustrative purposes and should not be construed as limiting this disclosure, as various other relationships between the first wheel, the second wheel, and the steering wheel input can be implemented, such as other linear, nonlinear, and / or exponential relationships, as well as other variations contemplated herein.

[0038]

[0039] Table 1

[0040] In some embodiments, a first wheel and a second wheel, driven at different speeds, are located on the same side of the vehicle. For example, the first wheel is the right front wheel 204, and the second wheel is the right rear wheel 208. Based on the location of the first and second wheels on the same side of the vehicle, a differential wheel speed corresponding to the travel path of each wheel is determined. In some embodiments, a first wheel and a second wheel, driven at different speeds, are located at the rear or front of the vehicle. Based on the location of the first and second wheels on the vehicle, a differential wheel speed corresponding to the travel path of each wheel is determined.

[0041] In some implementations, when making a right turn, vehicle 200 may provide forward torque (T0) to the left wheel 250 (e.g., left front wheel 202 and left rear wheel 206) based on a turning path used to achieve the target wheel speed of the vehicle. F3 and T F4 In some implementations, the vehicle may provide forward torque (T0) to the right wheel 260 (e.g., the right front wheel 204 and the right rear wheel 208) based on the turning path of the wheels used to achieve a target wheel speed (e.g., the target wheel speed may be proportional to the accelerator pedal input). F1 and T F2 For example, vehicle 200 can provide forward torque T to the right front wheel 204. F1 Provide forward torque T to the left front wheel 202 F3 Provides forward torque T to the left rear wheel 206 F4 It can also provide forward torque T to the right rear wheel 208. F2 In some embodiments, vehicle 200 may supply torque to the wheels (e.g., left front wheel 202, right front wheel 204, left rear wheel 206, and right rear wheel 208) to achieve a target wheel speed (e.g., the target wheel speed may be proportional to the accelerator pedal input). In some embodiments, the forward torque T F1 T F2 T F3 and T F4 Each of these is an independent torque and a function of the corresponding wheel steering angle. For example, the right front wheel 204 can follow a travel path similar to the vehicle's center position, thus having a lower differential speed compared to the vehicle speed, and therefore, the torque T of the left front wheel 202... F3 Compared to the required torque T F1 With a minor change, the left front wheel is positioned on a travel path that is larger than the vehicle's travel path.

[0042] In some embodiments, the left front wheel 202 and the right front wheel 204 may be connected via a drive shaft (not shown). In some embodiments, when making a right turn, the vehicle 200 may determine the steering wheel angle of the vehicle—for example, a 30-degree right turn. Based on the determined steering wheel angle, the vehicle may determine the differential wheel speeds of the vehicle's wheels. For example, the wheel speed of the left front wheel 202 may be different from the wheel speed of the right rear wheel 208. The vehicle may provide independent forward torque (T0) to the wheels on the left side 250 of the vehicle (e.g., the left front wheel 202 and the left rear wheel 206). F3 and T F4 In some implementations, the vehicle may provide forward torque (T0) to the wheels on the right side 260 of the vehicle (e.g., the right front wheel 204 and the right rear wheel 208). F1 and T F2 For example, the vehicle can provide a forward torque T to the right front wheel 204. F1 It can also provide forward torque T to the right rear wheel 208. F2 In some implementations, the vehicle may provide forward torque (T0) to the wheels on the left side 250 of the vehicle (e.g., the left front wheel 202 and the left rear wheel 206). F3 and T F4 For example, vehicle 200 can provide forward torque T to the left front wheel 202. F3 It can also provide forward torque T to the left rear wheel 206. F4 .

[0043] In some implementations, the vehicle can provide forward torque (T) F1 T F2 T F3 and T F4This allows for the application of steering wheel input to wheels 202 and 206 on the left side 250 and wheels 204 and 208 on the right side 260 of the vehicle, respectively. In response to receiving steering wheel input via 211, the vehicle's rotation center 201 is determined. The rotation center is the center of concentric circles, each representing the travel path of the corresponding wheel. The travel path (i.e., the concentric circle) of each wheel is adjusted based on the steering wheel angle. For example, a higher steering wheel angle results in a smaller turning path (i.e., a smaller concentric circle radius) for adjusting the vehicle path (e.g., the concentric circle). Conversely, if only small turns are being made, a larger turning path (i.e., a larger concentric circle radius) is used for adjusting the vehicle path. The vehicle can determine the differential speed between the first and second wheels based on the steering wheel input. For example, based on the vehicle's identification of its travel path, the wheels of the vehicle may have different travel paths. During a right turn, the left front wheel 202 has a longer travel path than the vehicle's center travel path because this wheel is positioned on the left side of the vehicle making the right turn. This travel path is still longer than the travel path of the right rear wheel 208 on the right side of the vehicle, which has a shorter travel path. Based on the above example, the vehicle determines the differential wheel speed between the first and second wheels. (Illustrative) Figure 2 In the diagram, the length of the arrow indicates the amount of torque to be applied to the wheel. For example, in a right turn, the left front wheel 202 requires an additional forward torque T. F3 The right rear wheel 208 needs to reduce the forward torque T. F2 The differential wheel speed between the first wheel (e.g., the left front wheel 202) and the second wheel (e.g., the right rear wheel 208) is determined based on the corresponding speed. For example, when the vehicle is traveling at 5 mph, the wheel speed at the first wheel (e.g., the left front wheel 202) can be set to approximately 6.5 mph and the wheel speed at the second wheel (e.g., the right rear wheel 208) can be set to approximately 4 mph. For example, on a relatively uniform ground surface, vehicle 200 follows a vehicle path where the vehicle's center of rotation 201 is located at the center of concentric circles, and the vehicle maintains a central vehicle path while adjusting the travel path of each wheel to reduce resistance to steering input.

[0044] Assuming that the forward torque is maintained on the right 260 wheels (204 and 208) and the left 250 wheels (202 and 206), the differential wheel speed between the first and second wheels reduces the resistance to steering input and provides stability when driving on extremely low friction surfaces to prevent excessive wheel slip.

[0045] In some implementations, vehicle 200 can operate in specific modes (e.g., hill-climb mode, yaw mode, etc.) in both turning directions (e.g., right turn and left turn). This mode can be entered or triggered in response to a request from a vehicle occupant. In some implementations, vehicle 200 can receive steering wheel input (i.e., turning) instructions. For example, vehicle 200 can receive a right turn instruction, which would cause the vehicle to turn right. In another example, vehicle 200 can receive a left turn instruction, which would cause the vehicle to turn left. Figure 2 A right turn is described; however, those skilled in the art will recognize that a similar technique can be used to perform a left turn.

[0046] The foregoing Figure 2 The principles of this disclosure are merely illustrative, and various modifications can be made by those skilled in the art without departing from the scope of this disclosure. The above embodiments are presented for illustrative purposes and not for limitation. For example, any combination of motors 212, 214, 216, and 218 and powertrains can be used in vehicle 200 according to this disclosure. In some examples, Figure 2 The rear motors 216 and 218 can be used in combination with a single front motor 212. According to this configuration, the vehicle 200 includes three motors (one front motor and two rear motors). In another example, the single rear motor 216 can be combined with... Figure 2 The two front motors 212 and 214 are used in combination. According to this configuration, the vehicle 200 includes three motors (two front motors and one rear motor).

[0047] Figure 3 Another top sectional view of an exemplary vehicle according to some embodiments of the present disclosure is shown, illustrating the turning path of each wheel. In some embodiments, vehicle 300 may be a two-door sedan, a four-door sedan, a truck, a sports utility vehicle, a large van, a minivan, a delivery van, a bus, or any other type of vehicle.

[0048] In some embodiments, vehicle 300 may include a left front wheel 302, a right front wheel 304, a left rear wheel 306, and a right rear wheel 308. In some embodiments, vehicle 300 may include a motor 212. Motor 212 may be connected to the left front wheel 302 (e.g., via a belt, chain, gear, or any other connecting device). Vehicle 300 may also include motors 214, 216, and 218, which are similarly connected to wheels 304, 306, and 308, respectively. In some embodiments, motors 212, 214, 216, and 218 may be configured to provide forward or rearward torque to their respective wheels 302, 304, 306, and 308.

[0049] In some embodiments, motors 212, 214, 216, and 218 may be any type of motor capable of generating power (e.g., gas engine, electric motor). In some embodiments, motors 212, 214, 216, and 218 may be devices connected to a primary single motor (not shown) and configured to independently and instantaneously transmit power from the single motor to wheels 302, 304, 306, and 308, respectively.

[0050] In some implementations, vehicle 300 may include Figure 1 The processing circuit 122. In some embodiments, the processing circuit 122 may include an onboard vehicle computer capable of controlling multiple features or capabilities of the vehicle. In some embodiments, the processing circuit 122 may be communicatively connected to the vehicle's user inputs 102, 104, 105, the vehicle's sensors 111 to 120, and transient or non-transient memory (e.g., memory storing mechanisms for operating the vehicle).

[0051] In some embodiments, vehicle 300 may include multiple sensors. For example, some of these multiple sensors may include a speed sensor 118 for determining the speed of vehicle 300, a steering wheel angle sensor 121 for determining the degree of rotation of the front wheels 302, 304 of vehicle 300, a vehicle rotation sensor 114 for determining the rotation of vehicle 300 in vehicle yaw mode, a wheel rotation sensor 112 for determining the slippage of each of the wheels 302, 304, 306, and 308 of vehicle 300, and an accelerometer sensor 120 for determining the acceleration of the vehicle.

[0052] In some implementations, the processing circuitry 122 of vehicle 300 may be able to directly control features of vehicle 300 with or without user input. In one example, the processing circuitry 122 may be able to actuate motor 212 to provide a specified amount of rearward or forward torque to the left front wheel 302. Similarly, the processing circuitry 122 may be able to actuate any of motors 214, 216, and 218 to provide a specified amount of rearward or forward torque to wheels 304, 306, and 308, respectively.

[0053] In some embodiments, the processing circuitry 122 of vehicle 300 can control the speed difference between the vehicle's wheels when one or more conditions are met. For example, a user can press a button, turn the steering wheel, or turn a lever to request the vehicle to turn. However, control of the wheel speed difference can be initiated without user input. In some embodiments, as an alternative to or supplement to a user request, the processing circuitry 122 can receive an instruction for the requested turning of vehicle 300. For example, the vehicle can receive input for a right turn or a left turn. In some embodiments, the processing circuitry 122 can determine whether the front wheels 302 and 304 are aligned parallel to vehicle 300. In some embodiments, to activate control of the wheel speed difference, wheels 302 and 304 need to move from a position aligned parallel to vehicle 300 to a misaligned position. To reduce resistance to steering input and provide stability when vehicle 300 turns, the speed difference between wheels 302 and 304 can be greater than 10% based on the steering wheel input used to counteract different turning paths of the wheels. In some embodiments, the one or more front wheels 302 and 304 of vehicle 300 can be a steering wheel. In some embodiments, the one or more rear wheels 306 and 308 of the vehicle 300 may be a steering wheel. In another embodiment, the one or more rear wheels 306 and 308 and the one or more front wheels 302 and 304 may be a steering wheel.

[0054] In some embodiments, when the vehicle is operated during cornering, the processing circuitry 122 of vehicle 300 may participate in controlling the speed difference. In controlling the speed difference between the vehicle's wheels, the processing circuitry 122 may (e.g., by using motors 214 and 218) provide forward torque to the right wheel 360 (i.e., the right front wheel 304 and the right rear wheel 308). In some embodiments, the processing circuitry 122 may, for example, provide forward torque to the left wheel 350 of vehicle 300 (i.e., the left front wheel 302 and the left rear wheel 306) by using motors 212 and 216. When vehicle 300 is cornering, vehicle 300 will maintain a vehicle speed (e.g., 5 mph), but the individual wheel speed of each of the wheels 302, 304, 306, and 308 of vehicle 300 will change based on the vehicle's geometry (e.g., wheelbase, vehicle trajectory, and tire rotation angle).

[0055] In some implementations, differential wheel speeds can be controlled when the vehicle drives over a large rock or boulder and one of its wheels is off the ground. In some implementations, a speed control mode is automatically entered in response to one or more of the vehicle's wheels spinning freely. For example, when the vehicle drives over a large rock or boulder and one of its wheels is off the ground, processing circuitry 122 can automatically enter speed control mode. Processing circuitry 122 can control the speed of each wheel to rotate at the same speed while driving in a straight line. Processing circuitry 122 will adjust the differential wheel speeds according to the turning angle to make turning easier for the vehicle.

[0056] The foregoing Figure 3 The present invention is merely illustrative of the principles of this disclosure, and various modifications can be made by those skilled in the art without departing from the scope of this disclosure. The above embodiments are presented for illustrative purposes and not for limitation. Figure 3 The driving path of the vehicle's center around the rotation center 201 and the driving path of each wheel of the vehicle are further illustrated based on the steering wheel angle. In some embodiments, the vehicle 300 may include a vehicle rotation center 201, which is the center of concentric circles, each circle representing the driving path of a corresponding wheel of the vehicle. Based on the steering wheel angle, the processing circuit 122 determines the left front driving path 312 of the left front wheel 302, the right front driving path 314 of the right front wheel 304, the left rear driving path 316 of the left rear wheel 306, and the right rear driving path 318 of the right rear wheel 308. For example, the processing circuit 122 may determine the turning radius (distance from the wheel to the rotation center 201) of each wheel's driving path based on the steering wheel angle.

[0057] In some embodiments, according to this disclosure, a vehicle yaw mode can be used on a vehicle having any combination of axles. For example, vehicle 300 may be based on a steering axle and a non-steering axle. The steering axle may be coupled to one or more wheels, which will cause vehicle 300 to steer in one direction. In some embodiments, the steering axle may be located at the front or rear of vehicle 300. For example, when a user provides input for steering the vehicle, the front or rear wheels will turn. In some embodiments, the non-steering axle may be coupled to one or more wheels, which will provide torque to the vehicle. In some embodiments, the vehicle may provide two axles (e.g., a steering axle and a non-steering axle), as in vehicle 300 (…). Figure 3The configuration shown in [the document] is illustrated. In some embodiments, the vehicle may provide three or more axles. For example, the three or more axles may provide at least one steering axle and two or more non-steering axles. According to this configuration, when the at least one steering axle is rotated so that the corresponding wheel is aligned parallel to the vehicle, the vehicle can enter a yaw mode. In some embodiments, the at least one steering axle may include a motor at each wheel. In some embodiments, each motor may provide forward torque to the vehicle at one wheel and rearward torque to the vehicle at the other wheel attached to the steering axle. In some embodiments, according to this disclosure, two or more non-steering axles may provide rearward torque on the same side of the vehicle corresponding to the rearward torque of the steering axle, and forward torque on the same side of the vehicle corresponding to the forward torque of the steering axle.

[0058] In some implementations, wheel speed differential control or any other mode, or no mode at all, can be used in any vehicle capable of distributing torque and / or braking to the wheels. For example, the vehicle may provide independent torque distribution to the right wheel 260 and the left wheel 250. According to another example, the vehicle may provide independent and varying degrees of torque and braking distribution to the right wheel 260 and the left wheel 250. The foregoing allows the driver to have a precise speed differential that reduces resistance to steering input control as the vehicle travels along a center travel path.

[0059] Figure 4 An illustrative example of the interior of a vehicle 400 characterized by a graphical user interface 402 according to some embodiments of the present disclosure is depicted. In some embodiments, the graphical user interface 402 may refer to something integrated into the vehicle (such as...) Figure 4The vehicle 400 is a component coupled to or accessible by the vehicle. The vehicle 400 is equipped with a graphical user interface 402 for enabling / disabling the vehicle system, including options for enabling and disabling control of speed differentials or any other modes. For example, a user in the vehicle 400 can use the graphical user interface 402 to access options on the vehicle 400. The vehicle 400 is also equipped with an accelerator pedal 404 configured to provide torque to achieve a target wheel speed (e.g., the left front wheel 202, right front wheel 204, left rear wheel 206, and right rear wheel 208) of the wheels (e.g., the target wheel speed may be proportional to the accelerator pedal input). The vehicle 400 is also equipped with a steering wheel 406 configured to provide steering to the vehicle. Processing circuitry (e.g., processing circuitry 122 of vehicle 100 or 200) can use the rotation of the steering wheel 406 to determine the steering wheel angle. In some embodiments, a graphical user interface 402 may be integrated into a vehicle 400 or user equipment for accessing such vehicle systems when using the vehicle 400. In some embodiments, the vehicle system displayed on the graphical user interface 402 may be communicatively connected to user input to the vehicle 400 (e.g., a microphone and speaker for providing voice commands). For example, a user may provide a voice command to activate control of a speed difference, and an audio system integrated into the vehicle 400 may translate such a command to enter that mode.

[0060] Figure 5 A front view of an exemplary steering wheel 500 of a vehicle (e.g., vehicle 100 or 200) according to some embodiments of the present disclosure is shown. In some embodiments, the steering wheel 500 may include a first threshold 506 (e.g., half-turn). If the rotation 502 of the steering wheel 500 does not reach the first threshold 506, the vehicle can operate in normal mode without controlling the speed difference of the vehicle's wheels. In some embodiments, the first threshold 506 may have an associated false stop. For example, when a user rotates the steering wheel 500 to the first threshold 506, the user may experience resistance (e.g., provided by a spring, pawl, or any other type of mechanism). In some embodiments, if the user rotates the steering wheel 500 beyond the first threshold 506 (e.g., by overcoming the false stop resistance), the processing circuitry 122 may begin operating the vehicle with a speed difference.

[0061] In some embodiments, the steering wheel 500 may include a second threshold 508 (e.g., 2 full turns). In some embodiments, the second threshold 508 is optional and other techniques may be used to activate the overcompensation mode. For example, the second threshold 508 may be present in vehicles where the steering wheel 500 is not mechanically connected to the vehicle's wheels (e.g., in drive-by-wire vehicles). The overcompensation mode may be triggered upon initiating a sharp turn, thereby causing resistance to each wheel. As part of the overcompensation mode, the vehicle may further apply braking to the vehicle's wheels to achieve differential wheel speeds. In some embodiments, the vehicle may amplify the target wheel speed of each wheel while in overcompensation mode to reduce the turning radius and increase the differential speed. For example, the differential wheel speed may be scaled up to a value greater than calculated. For example, if the target speed of the left wheel (e.g., the left front wheel 202) is 15% greater than the vehicle speed (e.g., 5 mph), the overcompensation mode may increase that target wheel speed of the left front wheel 202 to a faster target wheel speed (e.g., 30% greater). Similarly, if the right wheel (e.g., the right rear wheel) is at 85% of the vehicle speed (e.g., 5 mph) when making a right turn, the overcompensation mode can further reduce the wheel speed to 70% of the vehicle speed. This overcompensation will cause the left wheel (e.g., the left front wheel 202) to over-rotate and the right wheel (e.g., the right rear wheel 208) to under-rotate, resulting in additional rotation of the vehicle.

[0062] It should be understood that during anti-slip cornering in normal driving mode, the center of rotation is defined by the spatial arrangement of the wheels and the steering wheel angle of the front wheels. As the steering wheel rotates further away from its center position, the vehicle's center of rotation moves closer to the vehicle's position. In some implementations, when using the overcompensated mode discussed above, control of the speed difference allows the center of rotation to be closer to the vehicle's position than could be achieved by the angle of the individual front wheels (due to wheel resistance). In some implementations, the steering wheel rotation exceeds a first threshold amount to adjust the vehicle's turning path. Based on adjusting the vehicle's turning path, the turning path of each wheel is adjusted, thereby adjusting the speed difference for the vehicle's wheels. For example, when the vehicle makes another turn, to counteract the increased resistance on the vehicle's left front wheel 202 and right rear wheel 208, the processing circuit 122 adjusts the torque to each wheel based on the steering wheel input.

[0063] In some implementations, the amount by which the steering wheel is turned beyond a second threshold controls the distance from the path of each wheel of the vehicle to the center point (i.e., the center of concentric circles, each circle representing the travel path of the corresponding wheel). For example, when the steering wheel is turned beyond the second threshold, a rearward torque may begin to be applied to the right rear wheel 208 as part of overcompensation. As the amount of steering wheel turn beyond the second threshold increases, the relative amount of the rearward torque on the right rear wheel 208 may increase relative to the amount of the forward torque applied to the left front wheel 202. When the steering wheel is turned to its maximum extent, the rearward torque applied to the right rear wheel 208 may be approximately equal to the forward torque applied to the left front wheel 202.

[0064] Figure 6 An exemplary flowchart depicts a process 600 according to several embodiments of the present disclosure for controlling the speed difference between the wheels of a vehicle by setting the differential speed of the wheels. In some embodiments, process 600 may be performed by vehicle 200 ( Figure 2 ) or 300 Figure 3 The processing circuit 122 executes the process. It should be noted that process 600 or any of its steps can be performed by... Figure 1 The process is executed on or provided by the system. Furthermore, one or more steps of process 600 may be incorporated into or combined with one or more other steps described herein.

[0065] Process 600 begins at 602, where processing circuitry 122 determines the vehicle's wheel steering angle. For example, processing circuitry 122 may use signals from steering wheel angle sensor 121 to monitor the wheel steering angle and to monitor user input via input on steering wheel 406 or any other input. For example, re-referencing... Figure 3 Whether the rotation amount or angle of the vehicle's front wheels is sufficient (e.g., the rotation angle of wheels 202 and 204). In some embodiments, the processing circuit 122 may use a steering wheel angle sensor 121 connected to the steering column to determine the steering wheel angle of wheels 202 and 204.

[0066] Process 600 continues at 604, where processing circuit 122 determines whether the value of the steering wheel angle is greater than a threshold. For example, the threshold for the steering wheel angle can be set to 5 degrees or any other value. If processing circuit 122 determines that the value of the steering wheel angle is greater than the threshold ("Yes" at 604), processing circuit 122 proceeds to step 606. On the other hand, if processing circuit 122 determines that the value of the steering wheel angle is less than the threshold ("No" at 604), then at 610, the vehicle can apply equal torque to the first and second wheels.

[0067] Process 600 continues at 606, where processing circuitry 122 may proceed based on the result of step 604. At 606, processing circuitry 122 may determine the differential wheel speed between the first wheel and the second wheel of the vehicle based on the wheel steering angle. In some embodiments, the first wheel may be selected from any one of wheels 202, 204, 206, and 208, and the second wheel may be the other wheel among wheels 202, 204, 206, and 208 that was not selected for the first wheel. The differential wheel speed may be determined based on the turning path of each selected wheel.

[0068] In some implementations, when the vehicle is turning, the vehicle speed is maintained and the differential wheel speeds are compared between the two wheel speeds, for example...

[0069] The first wheel speed and the second wheel speed are shown in Equation 2 below. In some embodiments, the differential wheel speed is compared to any of these wheels, as shown in the following exemplary equation:

[0070] The speed difference between the first and second wheels = R 第1车轮 / R 第2车轮 (Equation 1)

[0071] The speed difference between the first and third wheels = R 第1车轮 / R 第3车轮 (Equation 2)

[0072] The speed difference between the first and fourth wheels = R 第1车轮 / R 第4车轮 (Equation 3)

[0073] Where R 第1车轮 R is the turning radius of the vehicle's first wheel. 第2车轮 R is the turning radius of the vehicle's second wheel. 第3车轮 It is the turning radius of the vehicle's third wheel, and R 第4车轮 It is the turning radius of the vehicle's fourth wheel.

[0074] In some implementations, when the vehicle is turning, the vehicle speed is maintained and the differential wheel speed is compared by comparing the speed of each wheel to the vehicle speed, as shown in the following exemplary equation:

[0075] The speed difference between the first wheel and the center of the vehicle = R 第1车轮 / R 车辆中心 (Equation 4)

[0076] The speed difference between the second wheel and the center of the vehicle = R 第2车轮 / R 车辆中心 (Equation 5)

[0077] The speed difference between the third wheel and the center of the vehicle = R 第3车轮 / R 车辆中心 (Equation 6)

[0078] The speed difference between the fourth wheel and the center of the vehicle = R 第4车轮 / R 车辆中心 (Equation 7)

[0079] Where R 第1车轮 R is the turning radius of the vehicle's first wheel. 第2车轮 R is the turning radius of the vehicle's second wheel. 第3车轮 R is the turning radius of the vehicle's third wheel. 第4车轮 It is the turning radius of the vehicle's fourth wheel, and R 车辆中心 It is the turning radius of the vehicle's center.

[0080] The foregoing equations (Equations 2 to 8) are merely illustrative of the principles of this disclosure, and various modifications can be made by those skilled in the art without departing from the scope of this disclosure. The above embodiments are presented for illustrative purposes and not for limitation. For example, any combination of differences can be stored in a lookup table, retrieved based on the turning angle, and applied to the appropriate wheel based on the turning direction.

[0081] In some embodiments, as part of performing a turn, processing circuit 122 may determine the turning direction (e.g., performing a right turn or a left turn). In some embodiments, processing circuit 122 may determine the first and second wheels based on the vehicle's turning path. For example, in response to receiving a wheel steering angle for a right turn, processing circuit 122 determines that the left front wheel (202) is the first wheel and the right rear wheel (208) is the second wheel. In another example, in response to receiving a wheel steering angle for a right turn, processing circuit 122 determines that the left front wheel (202) is the first wheel and the right front wheel (204) is the second wheel. Any possible combination of wheels 202, 204, 206, and 208 may be determined as the first and second wheels of the vehicle.

[0082] At 608, processing circuitry 122 can independently apply torque to the first and second wheels based on the differential wheel speed. For example, if the differential wheel speed is 40%, each of the first and second wheels is adjusted such that the output torque differs by approximately 40% between the first and second wheels. If the vehicle is traveling at 5 mph, the torque applied to the first wheel can be increased to raise the wheel speed to approximately 6 mph, while the torque applied to the second wheel can be decreased to lower the wheel speed to approximately 4.25 mph. In some embodiments, the differential speed is determined based on the first wheel. In another embodiment, the differential speed is determined based on the second wheel. In yet another embodiment, the differential wheel speed is determined based on a target vehicle speed (e.g., 5 mph). In the above embodiments, processing circuitry 122 can actuate motors 212 and 218 to provide independent torque to wheels 202 and 208. Furthermore, processing circuitry 122 can actuate motors 214 and 216 to provide independent torque to wheels 204 and 206. In some implementations, step 606 is executed in response to the user turning the steering wheel or in response to the user pressing an option on the vehicle's graphical user interface 402. In some implementations, step 606 begins by independently adjusting the torque applied to the wheels based on monitoring sensor data. For example, the torque is adjusted independently regardless of accelerator pedal input. Generally, the torque is increased until a speed difference between the first and second wheels is achieved, and thus, the vehicle reduces drag when cornering. In some implementations, processing circuitry 122 continues to examine the wheel steering angle to determine the differential wheel speed. Based on the increased wheel steering angle, processing circuitry 122 determines the new differential wheel speed between the first and second wheels and independently adjusts the torque applied to the first and second wheels. For example, after applying torque to the first and second wheels based on a first differential speed (e.g., between the first and second wheels) and a 10-degree steering wheel input, processing circuitry 122 may restart at 602 and determine a second differential speed (e.g., between the first and second wheels) based on a 20-degree steering wheel input.

[0083] Figure 7 An exemplary flowchart depicts a process 700 for controlling the speed difference of the wheels of a vehicle by setting a target wheel speed. In some embodiments, process 700 may be performed by vehicle 200 ( Figure 2 ) or 300 Figure 3 The processing circuit 122 executes the process. It should be noted that process 700 or any of its steps can be performed by... Figure 1 The process is executed on or provided by the system. Furthermore, one or more steps of process 700 may be incorporated into or combined with one or more other steps described herein.

[0084] Process 700 begins at 702; similar to step 602, processing circuitry 122 determines the wheel steering angles of the vehicle. The wheel steering angles affect the vehicle's center of rotation. For example, processing circuitry 122 can use signals from steering wheel angle sensor 121 to monitor the wheel steering angles and user input via input on steering wheel 406 or any other input. In some embodiments, processing circuitry 122 can use sensors connected to the steering column to determine the steering wheel angles of wheels 202 and 204.

[0085] Process 700 continues at 704 and 706. Each of these steps can be performed in any order, in parallel, or substantially simultaneously to reduce lag or increase the speed of the system or method. At 704, processing circuitry 122 determines a first target wheel speed for the first wheel of the vehicle. In some embodiments, the first wheel can be selected from any one of wheels 202, 204, 206, and 208, and the first target wheel speed is determined based on the path of the respective wheel.

[0086] At 706, processing circuitry 122 determines a second target wheel speed for the second wheel of the vehicle. In some embodiments, the second wheel may be selected from wheels 202, 204, 206, and 208, other than the first wheel, and the second target wheel speed is determined based on the path of the respective wheel. In some embodiments, the first and second wheels are at different distances from the rotation center defined by the wheel steering angle, and therefore the first and second target wheel speeds are different. Different wheel speed targets may be determined based on the turning path of each selected wheel. As part of performing a turn, processing circuitry 122 may determine that a right turn has been performed. In some embodiments, processing circuitry 122 may determine the first and second wheels based on the turning path of the vehicle. For example, in response to receiving a wheel steering angle for a right turn, processing circuitry 122 determines that the left front wheel (202) is the first wheel and the right rear wheel (208) is the second wheel. In another example, in response to receiving a wheel steering angle for a right turn, processing circuitry 122 determines that the left front wheel (202) is the first wheel and the right front wheel (204) is the second wheel. Any possible combination of wheels 202, 204, 206 and 208 can be identified as the first and second wheels of the vehicle.

[0087] At 706, processing circuit 122 can independently apply torque to the first wheel based on a first target wheel speed. For example, when the vehicle is traveling at 5 mph, the first target wheel speed can be determined to be 6 mph based on the steering wheel angle. In some embodiments, the vehicle is traveling at 5 mph while going straight (i.e., the wheel steering angle is "0" and all wheels are turning at approximately the same speed), and in response to determining a change in the steering wheel angle, the torque applied to the first wheel can be increased to raise the wheel speed to the first target wheel speed of 6 mph. At 708, processing circuit 122 can independently apply torque to the second wheel based on a second target wheel speed. In some embodiments, the torque applied to the second wheel can be reduced to lower the wheel speed to approximately 4.25 mph. For example, in response to receiving a right turn instruction, processing circuit 122 determines that the left wheels (202 and 206) are the outer wheels and the right wheels (204 and 208) are the inner wheels. In another example, in response to receiving a left-turn instruction, processing circuit 122 determines that the left wheels (202 and 206) are the inner wheels and the right wheels (204 and 208) are the outer wheels. In some embodiments, processing circuit 122 may provide independent torque to the left wheel 250 and the right wheel 260 of the vehicle. For example, processing circuit 122 may actuate motors 212, 214, 216, and 218 to provide independent forward torque to wheels 202, 204, 206, and 208. In some embodiments, the vehicle may continuously monitor the steering wheel angle and adjust the corresponding target speed of the vehicle's wheels based on changes in the steering wheel. For example, after initiating a turn, the vehicle steering wheel is further turned, and the target wheel speed is adjusted accordingly. Thus, processing circuit 122 may actuate motors 212, 214, 216, and 218 to adjust the forward torque to wheels 202, 204, 206, and 208, thereby achieving a travel path for each wheel.

[0088] In some embodiments, vehicle 200 may be a dual-motor vehicle with two motors (e.g., 212, 214) in the front of the vehicle. Based on this configuration, the first wheel may be the left front wheel 202 and the second wheel may be the right front wheel 204. In some embodiments, the dual motors may be located in the rear of the vehicle (e.g., 216, 218). Based on this configuration, the first wheel may be the left rear wheel 206 and the second wheel may be the right rear wheel 208. In yet another embodiment, the dual motors may be configured to have a first motor 212 powering a first side 250 and a second motor 214 powering a second side 260. In some embodiments, the first motor 212 and the second motor 214 are different. Based on this configuration, the first wheel may be the left front wheel 202 and the second wheel may be the right front wheel. Processing circuitry 122 may actuate the dual motors to adjust the forward torque on the first and second wheels, thereby achieving vehicle speed along the travel path.

[0089] It should be understood that process 700 is merely illustrative and various modifications can be made within the scope of this disclosure. For example, in some embodiments, steps 704 and 708 may also be performed for the third and fourth wheels, as in combination with... Figure 8 For a more detailed explanation, in some implementations, the vehicle includes an independent motor for each wheel. Based on the independent motor, the processing circuit 122 can perform steps 704 and 708 for each wheel.

[0090] Figure 8 An exemplary flowchart depicts a process 800 for controlling the wheel speed difference of a vehicle by independently monitoring the wheel speed of each wheel, setting a target wheel speed, and adjusting torque. In some embodiments, process 800 may be controlled by vehicle 200 ( Figure 2 ) or 300 Figure 3 The processing circuit 122 executes the process. It should be noted that process 800 or any of its steps can be performed by... Figure 1 The process is executed on or provided by the system. Furthermore, one or more steps of process 800 may be incorporated into or combined with one or more other steps described herein.

[0091] Process 800 begins at 802, where processing circuitry 122 receives steering wheel input. For example, the vehicle operator can rotate the steering wheel, which is configured to provide steering input to wheels 202 and 204.

[0092] Process 800 continues at 804, where processing circuit 122 determines whether the steering wheel input is a turn. For example, the value of the steering wheel angle may be determined to be greater than 0 degrees. If processing circuit 122 determines that the value of the steering wheel angle is greater than 0 degrees (i.e., the steering wheel input is a turn) ("Yes" at 804), then processing circuit 122 proceeds to step 806. On the other hand, if processing circuit 122 determines that the value of the steering wheel angle is zero degrees ("No" at 804), then at 822, processing circuit 122 may apply equal torque to the first wheel and the second wheel. In some embodiments, at 822, processing circuit 122 may apply torque independently to the first wheel and the second wheel, causing them to rotate at the same speed (e.g., in speed control mode).

[0093] Process 800 continues at 806, where processing circuit 122 may proceed based on the result of step 804. At 806, processing circuit 122 may determine the differential wheel speeds between the four wheels of the vehicle. For example, processing circuit 122 may determine a first differential wheel speed between the first and second wheels, a second differential wheel speed between the first and third wheels, and a third differential wheel speed between the first and fourth wheels. Each differential wheel speed is based on the steering wheel angle and may all be different. The differential wheel speeds may be determined based on any relevant factor, including the ratio between the other wheels. In some embodiments, the differential speed is based on the difference between the center of concentric circles (each concentric circle representing the travel path of the corresponding wheel) and the corresponding wheel. In some embodiments, the differential wheel speeds may all be related to one of the wheels (e.g., as a ratio or percentage compared to the right front wheel). In some embodiments, the differential wheel speeds may all be related to the vehicle speed / path (again, as a relative value or percentage). In some embodiments, the differential wheel speeds may be determined based on formulas such as those calculated using Equations 1 to 7. In some implementations, the differential wheel speed may be based on a lookup table that varies with steering wheel input. In other implementations, the differential wheel speed may be based on a lookup table that varies with tilt type and surface friction during vehicle movement.

[0094] Process 800 continues at steps 808 to 814. Each of these steps may be performed in any order or in parallel or substantially simultaneously to reduce hysteresis or increase the speed of the system or method. In some embodiments, steps 808 to 814 may be performed as part of step 806. For example, determining the differential wheel speed may include determining a target wheel speed for each wheel. At 808, processing circuitry 122 may determine a first target wheel speed for the first wheel of the vehicle. At 810, processing circuitry 122 may determine a second target wheel speed for the second wheel of the vehicle. At 812, processing circuitry 122 may determine a third target wheel speed for the third wheel of the vehicle. At 814, processing circuitry 122 may determine a fourth target wheel speed for the fourth wheel of the vehicle. In some embodiments, the first, second, third, and fourth wheels may be any one of wheels 202, 204, 206, and 208. In some embodiments, each of the first, second, third, and fourth target wheel speeds is determined based on the travel path of the respective wheel. For example, if the different wheel speeds are ratios to the vehicle speed, then the target wheel speed of a wheel is equal to the vehicle speed multiplied by the differential wheel speed ratio of that wheel. In another example, if the different wheel speeds are factors compared to the vehicle speed from a lookup table, then the target wheel speed of a wheel is equal to the vehicle speed multiplied by a factor for each wheel based on the vehicle's geometry.

[0095] In some embodiments, at 816, processing circuitry 122 can monitor signals from sensors coupled to the motor shafts of the four wheels to determine the wheel speed. In some embodiments, processing circuitry 122 can monitor signals from resolver 112 to determine the wheel speed. The wheel speed can be determined by calculating the number of rotations of the wheel over time. In yet another embodiment, the resolver can generate an alternating current (AC) signal. The AC signal generates an electrical waveform that is produced when the amplitude or amount of the signal changes in proportion to the sine of the angle of rotation of the resolver at any given moment. That is, the AC signal can be used to identify the complete rotation of the wheel. Based on the AC signal, processing circuitry 122 can determine the wheel speed of each wheel more accurately. In some embodiments, processing circuitry 122 can be communicatively connected to one or more speed sensors 118, which provide data indicating the speed of the vehicle. For example, Figure 1 The speed sensor 118 can provide data indicating the speed of the vehicle 200. In another example, the resolver 112 can provide data indicating the speed of each wheel of the vehicle 200, which can be extrapolated to the speed of the vehicle, such as the average of the two front wheels 202, 204 or a function of the speed of all wheels based on the steering angle.

[0096] In some implementations, process 800 continues at 818, where processing circuitry 122 can calculate the corresponding wheel speed for each corresponding wheel based on the corresponding signal in the monitored signals. For example, the wheel speed for each wheel can be calculated based on the monitored signal for that wheel.

[0097] In some embodiments, process 800 continues at 820, where processing circuitry 122 can independently adjust the torque applied to each corresponding wheel to achieve each corresponding target wheel speed. In some embodiments, the torque applied to the wheels can be increased or decreased to achieve the corresponding target wheel speed. For example, the target wheel speed for each wheel can be different. In some embodiments, processing circuitry 122 can actuate motors 212, 214, 216, and 218 to provide independent forward torque to each of wheels 202, 204, 206, and 208. In some embodiments, the vehicle can continuously monitor the steering wheel angle and adjust the corresponding target speeds of wheels 202, 204, 206, and 208 of the vehicle 200 based on changes in steering wheel 404. In some embodiments, processing circuitry 122 can actuate motors 212, 214, 216, and 218 to adjust the forward torque applied to wheels 202, 204, 206, and 208 to achieve the correct driving path for each wheel.

[0098] It should be understood that process 800 is merely illustrative and various modifications can be made within the scope of this disclosure. For example, in some embodiments, steps 808 to 814 may be omitted and step 806 may be performed in response to pressing the accelerator pedal 213. It should also be noted that processes 600, 700, and 800 may be combined sequentially, specific steps from each of processes 600, 700, and 800 may be combined to establish a separate process, and other possibilities exist.

[0099] It can be imagined that, Figures 1 to 8 The steps or descriptions in each figure can be used in conjunction with any one or more other embodiments of this disclosure. Those skilled in the art will recognize that... Figures 1 to 8 Some system components, steps, or descriptions in each figure may be optional and may be omitted in some embodiments. More generally, this disclosure is intended to be exemplary and not restrictive. Furthermore, relative to... Figures 6 to 8 The steps and descriptions described may be performed in an alternating order or in parallel to further serve the purposes of this disclosure. For example, each of these steps may be performed in any order or in parallel or substantially simultaneously to reduce the lag of the system or method or to increase its speed. Furthermore, it should be noted that, relative to... Figure 1 , Figure 2 and Figure 3 Any equipment or apparatus discussed may be used to perform Figure 6 , Figure 7 and Figure 8 One or more steps in the process.

[0100] The foregoing description is merely illustrative of the principles of this disclosure, and various modifications can be made by those skilled in the art without departing from the scope of this disclosure. The above embodiments are presented for illustrative purposes and not for limitation. This disclosure may also take many forms other than those expressly described herein. Therefore, it should be emphasized that this disclosure is not limited to the methods, systems, and apparatus expressly disclosed, but is intended to include variations and modifications thereof, which are within the spirit of the following claims.

Claims

1. A method for controlling the speed difference between the wheels of a vehicle, the method comprising: Determine the wheel steering angle of the vehicle; In response to determining that the wheel steering angle of the vehicle is lower than a first wheel steering angle threshold, equal torque is applied to the first wheel and the second wheel of the vehicle; In response to determining that the wheel steering angle of the vehicle exceeds a first wheel steering angle threshold: Determining the differential wheel speeds associated with the first wheel and the second wheel of the vehicle, wherein determining the differential wheel speeds includes: The first target wheel speed of the first wheel is determined based on the wheel steering angle and the vehicle speed; Determine the second target wheel speed of the second wheel based on the wheel steering angle and vehicle speed; and Torque is applied independently to the first wheel and the second wheel to achieve the first target wheel speed and the second target wheel speed; and In response to determining that the wheel steering angle of the vehicle continues to increase and exceeds a second wheel steering angle threshold, an overcompensation mode is activated to provide an overcompensation factor to the first wheel and the second wheel, wherein the second wheel steering angle threshold is greater than the first wheel steering angle threshold, wherein the vehicle is able to amplify the target wheel speed of each wheel to reduce the turning radius and increase the differential speed when in overcompensation mode, thereby causing additional rotation of the vehicle.

2. The method according to claim 1, wherein: The differential wheel speed is further determined based on at least one of the following: 1) Center of rotation, 2) Distance of the first wheel from the center of rotation, or 3) Distance of the second wheel from the center of rotation; and Applying torque independently to the first wheel and the second wheel includes: Apply a first torque to the first wheel to achieve the first target wheel speed; as well as A second torque is applied to the second wheel to achieve the second target wheel speed, wherein the first torque is different from the second torque.

3. The method according to claim 2, wherein: The vehicle includes a first motor configured to provide the first torque to the first wheel; and The vehicle includes a second motor configured to provide the second torque to the second wheel, wherein the first motor is different from the second motor.

4. The method according to claim 1, wherein: The vehicle includes four wheels, which are a first wheel, a second wheel, a third wheel, and a fourth wheel; Determining the differential wheel speed includes determining the corresponding target wheel speed for each of the first wheel, the second wheel, the third wheel, and the fourth wheel; and Applying torque independently includes applying torque independently to each of the four wheels based on the respective target wheel speed.

5. The method of claim 4, wherein the vehicle comprises four motors, each motor being configured to independently provide torque to a corresponding wheel based on the corresponding target wheel speed.

6. The method according to claim 5, wherein: Each of the four motors includes an electric motor with a motor shaft; and The method further includes: Signals from sensors coupled to the motor shafts of the four electric motors are monitored, wherein each sensor indicates the amount of rotation of the corresponding motor shaft; The corresponding wheel speed of each wheel is calculated based on the corresponding signal in the monitored signals; and In response to the calculated corresponding wheel speed of each corresponding wheel, the torque to each corresponding wheel is adjusted to achieve the corresponding target wheel speed.

7. The method according to claim 1, further comprising: Receive accelerator pedal input to determine the target speed of the vehicle; and Determining the differential wheel speed includes: The differential wheel speed between the first wheel and the second wheel of the vehicle is determined based on the vehicle's target speed and the wheel steering angle.

8. The method according to claim 1, wherein the first wheel steering angle threshold is 5 degrees.

9. The method according to claim 1, further comprising: The turning path of each wheel of the vehicle is determined based on the wheel steering angle, wherein the turning path of the vehicle defines the travel path of each wheel of the vehicle; as well as The differential wheel speed of each of the corresponding wheels of the vehicle is adjusted based on the determined corresponding turning path.

10. A vehicle for controlling the speed difference between the wheels of a vehicle, the vehicle comprising: A steering wheel configured to receive input from the vehicle's operator to turn the vehicle, wherein each turn is configured to generate a corresponding wheel steering angle for the vehicle. as well as Control circuit, the control circuit being configured to: The wheel steering angle of the vehicle is determined by the received input that causes the vehicle to turn; In response to determining that the wheel steering angle of the vehicle is lower than a first wheel steering angle threshold, equal torque is applied to the first wheel and the second wheel of the vehicle; In response to determining that the wheel steering angle of the vehicle exceeds a first wheel steering angle threshold: The differential wheel speeds associated with the first wheel and the second wheel of the vehicle are determined by the following steps: The first target wheel speed of the first wheel is determined based on the wheel steering angle and the vehicle speed; The second target wheel speed of the second wheel is determined based on the wheel steering angle and the vehicle speed; as well as Torque is applied independently to the first wheel and the second wheel to achieve the first target wheel speed and the second target wheel speed; as well as In response to determining that the wheel steering angle of the vehicle continues to increase and exceeds a second wheel steering angle threshold, an overcompensation mode is activated to provide an overcompensation factor to the first wheel and the second wheel, wherein the second wheel steering angle threshold is greater than the first wheel steering angle threshold. When the vehicle is in overcompensation mode, it can amplify the target wheel speed of each wheel to reduce the turning radius and increase the differential speed, thereby causing additional rotation of the vehicle.

11. The vehicle according to claim 10, wherein: The control circuit is configured to further determine the differential wheel speed based on at least one of the following: Based on 1) the center of rotation, 2) the distance of the first wheel from the center of rotation, or 3) the distance of the second wheel from the center of rotation; and The control circuit is configured to independently apply torque to the first wheel and the second wheel in the following manner: Apply a first torque to the first wheel to achieve the first target wheel speed; and A second torque is applied to the second wheel to achieve the second target wheel speed, wherein the first torque is different from the second torque.

12. The vehicle according to claim 11, wherein: The vehicle includes a first motor configured to provide the first torque to the first wheel; and The vehicle includes a second motor configured to provide the second torque to the second wheel, wherein the first motor is different from the second motor.

13. The vehicle according to claim 10, wherein: The vehicle includes four wheels, which are a first wheel, a second wheel, a third wheel, and a fourth wheel; The control circuit is configured to determine the differential wheel speed by determining a corresponding target wheel speed for each of the first wheel, the second wheel, the third wheel, and the fourth wheel; and The control circuit is configured to apply torque independently by applying torque to each of the four wheels independently based on the respective target wheel speed.

14. The vehicle of claim 13, wherein the vehicle comprises four motors, each motor being configured to independently provide torque to a corresponding wheel based on the corresponding target wheel speed.

15. The vehicle according to claim 14, wherein: Each of the four motors includes an electric motor with a motor shaft; The control circuit is further configured as follows: Signals from sensors coupled to the motor shafts of the four electric motors are monitored, wherein each sensor indicates the amount of rotation of the corresponding motor shaft; The corresponding wheel speed of each wheel is calculated based on the corresponding signal in the monitored signals; and In response to the calculated corresponding wheel speed of each corresponding wheel, the torque to each corresponding wheel is adjusted to achieve the corresponding target wheel speed.

16. The vehicle according to claim 10, further comprising: An accelerator pedal, configured to provide an accelerator pedal input for determining a target vehicle speed. The control circuit is further configured to determine the differential wheel speed in the following manner: The differential wheel speed between the first wheel and the second wheel of the vehicle is determined based on the vehicle's target speed and the wheel steering angle.

17. A method for controlling the speed difference between the wheels of a vehicle, the method comprising: Determine the wheel steering angle of the vehicle; In response to determining that the wheel steering angle of the vehicle is lower than a first wheel steering angle threshold, equal torque is applied to the first wheel and the second wheel of the vehicle; In response to determining that the wheel steering angle of the vehicle exceeds a first wheel steering angle threshold: The first target wheel speed of the first wheel of the vehicle is determined based on the wheel steering angle and the vehicle speed; The second target wheel speed of the vehicle's second wheel is determined based on the wheel steering angle and the vehicle speed; as well as The torque on the first wheel and the second wheel is adjusted independently to achieve the corresponding first target wheel speed and second target wheel speed. In response to determining that the wheel steering angle of the vehicle continues to increase and exceeds a second wheel steering angle threshold, an overcompensation mode is activated to provide an overcompensation factor to the first wheel and the second wheel, wherein the second wheel steering angle threshold is greater than the first wheel steering angle threshold. When the vehicle is in overcompensation mode, it can amplify the target wheel speed of each wheel to reduce the turning radius and increase the differential speed, thereby causing additional rotation of the vehicle.

18. The method of claim 17, wherein independently adjusting the torque on the first wheel and the second wheel comprises: Apply a first torque to the first wheel to achieve the first target wheel speed; as well as A second torque is applied to the second wheel to achieve the second target wheel speed, wherein the first torque is different from the second torque.

19. The method of claim 18, wherein: The vehicle includes a first motor configured to provide the first torque to the first wheel; and The vehicle includes a second motor configured to provide the second torque to the second wheel, wherein the first motor is different from the second motor.

20. The method of claim 18, wherein the first wheel and the second wheel are at different distances from the center of rotation and wherein the speed of the first target wheel is different from the speed of the second target wheel.

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