Road feel simulation system and control method

Abstract

This invention relates to a road feel simulation system and control method. The road feel simulation system includes a connected steering wheel, steering column, road feel motor, road feel motor controller, and chassis domain controller. When the steering wheel is turned, the road feel motor transmits a steering wheel signal to the road feel motor controller. The road feel motor controller processes the steering wheel signal and transmits it to the chassis domain controller. The chassis domain controller calculates the road feel feedback torque and transmits it to the road feel motor controller. The road feel motor is controlled to generate the road feel feedback torque, allowing the driver to perceive road conditions and vehicle status. This invention also provides a control method based on the road feel simulation system, including the road feel motor controller processing the steering wheel signal and transmitting it to the chassis domain controller; the chassis domain controller calculating the road feel feedback torque and feeding it back to the road feel motor controller, causing the road feel motor to generate the road feel feedback torque, which is then perceived by the driver. This invention can obtain feedback torque reflecting road conditions and vehicle driving status, and enable the driver to perceive it.

Description

Technical Field

[0001] This invention relates to the field of automotive steer-by-wire technology, specifically to a road feel simulation system and control method. Background Technology

[0002] Traditional steering systems connect the steering wheel and steering wheels via mechanical mechanisms, transmitting road conditions to the driver through a transmission system, ensuring the driver's perception of road conditions. However, the traditional mechanical structure limits the driver's handling stability and driving agility. Furthermore, with the rapid development of intelligent connected vehicles, achieving maneuverability such as turning on the spot and diagonal driving has gradually become an important direction for intelligent vehicle development. Traditional steering systems, limited by their structure, cannot achieve these functions. Steer-by-wire systems convert driver input into electrical signals to control the car, offering flexible handling and rapid response, highly meeting the development needs of intelligent vehicles. However, because steer-by-wire systems eliminate mechanical connections, they require a road feel simulation system to calculate feedback torque that reflects road conditions and vehicle driving status, which is then transmitted to the driver by the road feel feedback mechanism. This simulates the handling feel of a traditional steering system, allowing the driver to perceive the road and vehicle status through the steering wheel. Summary of the Invention

[0003] The purpose of this invention is to provide a road feel simulation system and control method to accurately obtain feedback torque that reflects road conditions and vehicle driving status, and transmit it to the driver so that the driver can accurately perceive road conditions and vehicle status.

[0004] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0005] A road feel simulation system includes a steering wheel, a steering column tube, a road feel motor, a road feel motor controller, and a chassis domain controller connected in sequence, wherein the chassis domain controller is equipped with a road feel control device.

[0006] Turning the steering wheel transmits steering angle and torque signals to the road feeler motor controller via the steering column tube and the road feeler motor. The road feeler motor controller processes the steering angle signal to obtain the steering wheel speed signal and transmits the steering angle, steering wheel speed, and steering torque signals to the chassis domain controller. The road feeler control device in the chassis domain controller calculates the road feeler feedback torque based on the steering angle, steering wheel speed, and steering torque signals and feeds the road feeler feedback torque back to the road feeler motor controller. The road feeler motor controller controls the road feeler motor to generate the road feeler feedback torque, which is then transmitted to the steering wheel via the steering column tube, allowing the driver to perceive road conditions and vehicle status.

[0007] Preferably, the road sensing control device includes:

[0008] The signal receiving module is used to acquire steering wheel angle signal, steering wheel speed signal, and steering wheel torque signal, as well as to collect chassis signals to obtain vehicle speed signal and front wheel angle signal;

[0009] The initialization module is used to convert the absolute position of the steering wheel into a relative position based on the steering wheel angle signal, calculate the initial return torque based on the relative position, and feed the initial return torque back to the road sensor motor controller. The road sensor motor controller controls the road sensor motor to generate the initial return torque, which is then transmitted to the steering wheel through the steering column tube to make the steering wheel return to center.

[0010] The road feel control algorithm module is used to calculate the road feel feedback torque by means of the resistance torque, soft limit torque, compensation torque and assist torque, and feed the road feel feedback torque back to the road feel motor controller. The road feel feedback torque is the sum of the resistance torque, soft limit torque, compensation torque and assist torque.

[0011] Among them, the steering wheel angle signal represents the rotation angle of the steering wheel as described later, the front wheel angle signal represents the rotation angle of the front wheel as described later, and the steering wheel speed signal represents the angular velocity of the steering wheel rotation as described later.

[0012] The absolute position of the steering wheel is the steering wheel position information sent by the road sensor motor controller, while the relative position of the steering wheel refers to the relative position of the steering wheel within a single revolution calculated in the initialization module of the road sensor control device. The relative position of the steering wheel within a single revolution is the angle value of the steering wheel at the absolute position modulo 360. For example, if the angle value of the steering wheel at the absolute position is 485°, then the angle value of the relative position of the steering wheel within a single revolution is 125°.

[0013] Preferably, the road feel control algorithm module includes:

[0014] The drag torque unit is used to calculate the drag torque based on the collected chassis signals and vehicle parameters;

[0015] The soft limit torque unit is used to calculate the soft limit torque based on the steering wheel angle signal and the angle at which the steering wheel is turned to the left or right limit position;

[0016] The compensation torque unit is used to calculate the compensation torque based on friction compensation, damping compensation, inertia compensation, and self-correction compensation.

[0017] The assist torque unit is used to obtain the assist torque by looking up a table.

[0018] The assist torque in the assist torque unit is obtained by looking up the map table, which is obtained based on experimental calibration.

[0019] Preferably, in the resistance torque unit, the formula for calculating the resistance torque is as shown in Equation I:

[0020]

[0021] In formula I, T z The values ​​represent the drag torque (N·m), m represents the total mass of the vehicle (kg), v represents the vehicle speed (m / s), l represents the wheelbase (m), the wheelbase is the distance between the front and rear axles, δ represents the front wheel rotation angle (rad), and ξ represents the front wheel tire trail (m). V The distance from the center of mass to the front axle is expressed in meters (m). h This represents the distance from the center of mass to the rear axle, in meters (m). (C) αH Represents the rear wheel lateral stiffness, in N / rad, C αV The values ​​represent: front wheel lateral stiffness (N / rad), Q (wheel load of a single tire in kg), β′ (kingpin inclination angle of the front wheel in rad), D (kingpin displacement of the front wheel in m), f (coefficient of friction between the tire and the ground), G1 (front axle load in N), and p (tire pressure of a single tire in kPa).

[0022] The resistance torque is divided into driving return torque and stationary return torque. The driving return torque is used to simulate the tire return torque generated by the tire trail and kingpin inclination during vehicle driving. In Equation I, when v≠0, it is the driving return torque. The stationary return torque is used to simulate the frictional resistance torque between the tire and the ground caused by the vertical load of the vehicle when the vehicle is turning in place. In Equation I, when v=0, it is the stationary return torque.

[0023] Among them, mass, wheelbase, tire trail, distance from center of gravity to front wheel, distance from center of gravity to rear wheel, rear wheel lateral stiffness, front wheel lateral stiffness, wheel load, kingpin inclination angle, kingpin displacement, coefficient of friction between tire and ground, steering axle load and tire pressure are all vehicle parameters, all obtained from experimental calibration.

[0024] Preferably, in the soft-limiting torque unit, the calculation formula for the soft-limiting torque is as shown in Equation II:

[0025]

[0026] In Equation II, T lim This represents the soft-limiting torque, in N·m, θ sw The angle of rotation of the steering wheel is expressed in rad, θ. lim This indicates the angle of rotation of the steering wheel to its left and right extreme positions, measured in rad (k). lim This represents the limit control torque coefficient, with units of N·m / rad. 2 .

[0027] The soft limiting torque uses a quadratic function model to simulate the limiting torque generated by the limiting device in a traditional steering system, making the change of the soft limiting torque smoother. The soft limiting torque T is introduced when the steering wheel is turned to its extreme position. lim .

[0028] Preferably, in the compensation torque unit, the calculation formula for the compensation torque is as shown in Equation III:

[0029] T c =T f +T d +T i +T a (III)

[0030] In Equation III, T c T represents the compensating torque. f T represents the friction compensation torque. d T represents the damping compensation torque. i T represents the inertial compensation torque. a This indicates the correcting compensation torque.

[0031] Compensation torque is divided into friction compensation, damping compensation, inertia compensation, and self-centering compensation. Friction compensation uses a hyperbolic tangent function to simulate the Coulomb friction torque between mechanical structures in a traditional steering system. This model has a continuous curve near zero speed, effectively eliminating abrupt changes in friction torque. Damping compensation is used to prevent accidental steering wheel manipulation by the driver in emergency situations; the faster the vehicle speed and the greater the angular velocity of the steering wheel rotation, the greater the damping compensation torque. Inertia compensation is used to compensate for the inertial torque generated by large angular accelerations, which can cause abrupt changes in steering wheel torque; it has a linear relationship with the angular acceleration of the steering wheel. Self-centering compensation is used when the output torque of the resistance module is too small to overcome friction and damping torques, providing appropriate compensation torque to help the steering wheel quickly return to center.

[0032] Preferably, the formula for calculating the friction compensation torque is shown in Equation IV:

[0033]

[0034] In equation IV, T f This represents the friction compensation torque, expressed in N·m, α. f The curve ascent coefficient, This represents the angular velocity of the steering wheel rotation, measured in rad / s, kJ / s. f This represents the friction compensation coefficient, with units of N·m.

[0035] Preferably, the formula for calculating the damping compensation torque is shown in Equation V:

[0036]

[0037] In formula V, T d This represents the damping compensation torque, expressed in N·m. This represents the angular velocity of the steering wheel rotation, measured in rad / s, kJ / s. d This represents the damping compensation coefficient, with units of N·m / (rad / s).

[0038] Preferably, the formula for calculating the inertial compensation torque is shown in Equation VI:

[0039]

[0040] In equation VI, T i This represents the inertial compensation torque, with units of N·m. This represents the angular acceleration of the steering wheel, measured in rad / s². 2 k i This represents the inertia compensation coefficient, with units of N·m / (rad / s). 2 ).

[0041] Preferably, the formula for calculating the corrective compensation torque is shown in Equation VII:

[0042] T a =k a θ sw (VII)

[0043] In equation VII, T a This represents the aligning compensation torque, in N·m, θ sw This indicates the steering wheel rotation angle, measured in rad (k). a This represents the positive correction compensation coefficient, with units of N·m / rad.

[0044] Among them, the limit control torque coefficient, curve ascent coefficient, friction compensation coefficient, damping compensation coefficient, inertia compensation coefficient, and alignment compensation coefficient were all obtained by experimental calibration.

[0045] Preferably, the road feel control device further includes a fault detection module for monitoring whether the steering wheel angle signal, steering wheel speed signal, and steering wheel torque signal are within a set range.

[0046] If the output of the road sensor motor controller is not within the set range, immediately interrupt the output to ensure the safety of system operation, and determine the cause of the fault based on the fault handling logic.

[0047] The steering wheel rotation angle ranges from -540° to 540°, the steering wheel rotation angular velocity ranges from -1000° / s to 1000° / s, and the steering wheel torque ranges from -10N·m to 10N·m.

[0048] Preferably, the fault detection module is also used to detect CAN signals.

[0049] Preferably, one end of the steering column tube is splined to the steering wheel, and the other end is keyed to the motor shaft of the road feel motor.

[0050] The road feel motor is a servo motor. The inner spline in the middle of the steering wheel is connected to the outer spline at one end of the steering column tube. The outer keyway on the shaft of the servo motor is connected to the inner keyway at the other end of the steering column tube via a flat key, so that the steering wheel and the steering column tube maintain precise coaxial rotation. The inner keyway at the other end of the steering column tube is connected to the outer keyway on the shaft of the servo motor via a flat key, so that the servo motor can accurately receive steering wheel angle and steering wheel torque information.

[0051] The present invention also provides a control method based on the road sense simulation system described herein, comprising:

[0052] The road sensor motor controller processes the steering wheel angle signal obtained from the road sensor motor to obtain the steering wheel speed signal. Then, it performs noise filtering on the steering wheel angle signal, steering wheel speed signal, and steering wheel torque signal and transmits them to the chassis domain controller.

[0053] The road feel control device in the chassis domain controller calculates the initial return torque by obtaining the steering wheel angle signal from the road feel motor controller and transmits it to the road feel motor controller. The road feel motor controller controls the road feel motor to generate the return torque, so that the steering wheel returns to center. Then, the road feel control device calculates the road feel feedback torque by obtaining the steering wheel angle signal, steering wheel speed signal, and steering wheel torque signal from the road feel motor controller, as well as the vehicle speed signal and front wheel angle signal from the chassis domain controller, and feeds the road feel feedback torque back to the road feel motor controller. The road feel motor controller controls the road feel motor to generate the road feel feedback torque and transmits it to the steering wheel through the steering column tube, so as to enable the driver to perceive the road conditions and vehicle status.

[0054] Preferably, the road sense control device includes a signal receiving module, an initialization module, a road sense control algorithm module, and a fault detection module;

[0055] The signal receiving module obtains steering wheel angle signal, steering wheel speed signal, and steering wheel torque signal from the road sensor motor controller, as well as vehicle speed signal and front wheel angle signal from the chassis domain controller. The signal receiving module filters out noise from the steering wheel angle signal, steering wheel speed signal, and steering wheel torque signal before transmitting them to the initialization module.

[0056] The initialization module first determines whether the received steering wheel angle signal, steering wheel speed signal, and steering wheel torque signal are within the set range. If they are within the set range, it calculates the relative position of the steering wheel in this revolution based on the received steering wheel angle signal, calculates the initial return torque based on the relative position of the steering wheel in this revolution, and transmits it to the road sensor motor controller. The road sensor motor controller controls the road sensor motor to generate the return torque, so that the steering wheel automatically returns to center.

[0057] The road feel control algorithm module calculates the resistance torque, soft limit torque, compensation torque, and assist torque through the resistance torque unit, soft limit torque unit, compensation torque unit, and assist torque unit in the road feel control algorithm module, respectively. The resistance torque, soft limit torque, compensation torque, and assist torque are added together to obtain the road feel feedback torque, and the road feel feedback torque is transmitted to the road feel motor controller through the CAN line.

[0058] The fault detection module monitors whether the CAN signal, steering wheel angle signal, steering wheel speed signal, and steering wheel torque signal are within the set range. If they are not within the set range, the output of the road sensor motor controller is immediately interrupted.

[0059] The beneficial effects of this invention are:

[0060] The road feel simulation system and control method of this invention transmit steering wheel angle and steering wheel torque signals to a road feel motor controller via a steering column tube and a road feel motor. The road feel motor controller processes the steering wheel angle signal to obtain a steering wheel speed signal and transmits the steering wheel angle signal, steering wheel speed signal, and steering wheel torque signal to a chassis domain controller. The road feel control device in the chassis domain controller calculates the steering wheel angle signal, steering wheel speed signal, and steering wheel torque signal to accurately obtain the road feel feedback torque reflecting the road surface conditions and vehicle driving state, and feeds the road feel feedback torque back to the road feel motor controller. The road feel motor controller controls the road feel motor to generate the road feel feedback torque, which is transmitted to the steering wheel via the steering column tube, enabling the driver to accurately perceive the road surface conditions and vehicle state. This compensates for the torque transmission problem caused by the lack of a mechanical structure between the steering wheel and steering wheels in steer-by-wire systems, and has significant application value in the field of automotive steer-by-wire technology. Attached Figure Description

[0061] Figure 1 This is a schematic diagram of the road feel simulation system of the present invention;

[0062] Figure 2 This is a schematic diagram of the road sensor control device.

[0063] Among them, 1-steering wheel, 2-steering column tube, 3-road sensor motor, 4-road sensor motor controller, 5-chassis domain controller, 51-road sensor control device, 6-motor bracket. Detailed Implementation

[0064] The embodiments of the present invention will be described below with reference to the accompanying drawings and preferred embodiments. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and various details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of the present invention. It should be understood that the preferred embodiments are only for illustrating the present invention and not for limiting the scope of protection of the present invention.

[0065] It should be noted that the illustrations provided in the following embodiments are only schematic representations of the basic concept of the present invention. Therefore, the drawings only show the components related to the present invention and are not drawn according to the actual number, shape and size of the components in the actual implementation. In the actual implementation, the form, quantity and proportion of each component can be arbitrarily changed, and the layout of the components may also be more complex.

[0066] Example 1

[0067] like Figure 1 and Figure 2 As shown, a road feel simulation system includes a steering wheel 1, a steering column tube 2, a road feel motor 3, a road feel motor controller 4, and a chassis domain controller 5 connected in sequence. The chassis domain controller 5 is equipped with a road feel control device 51.

[0068] When the steering wheel 1 is turned, the steering wheel angle signal and steering wheel torque signal are transmitted to the road sense motor controller 4 through the steering column tube 2 and the road sense motor 3. The road sense motor controller 4 processes the steering wheel angle signal to obtain the steering wheel speed signal, and transmits the steering wheel angle signal, steering wheel speed signal, and steering wheel torque signal to the chassis domain controller 5 through the CAN bus. The road sense control device 51 in the chassis domain controller 5 calculates the road sense feedback torque based on the steering wheel angle signal, steering wheel speed signal, and steering wheel torque signal, and feeds the road sense feedback torque back to the road sense motor controller 4. The road sense motor controller 4 controls the road sense motor 3 to generate the road sense feedback torque, which is transmitted to the steering wheel 1 through the steering column tube 2, enabling the driver to perceive the road conditions and vehicle status. Among them, the road feel motor 3 is a servo motor. The inner spline in the middle of the steering wheel 1 is connected to the outer spline at one end of the steering column tube 2. The outer keyway on the shaft of the road feel motor 3 is connected to the inner keyway at the other end of the steering column tube 2 through a flat key, so that the steering wheel 1 and the steering column tube 2 maintain precise coaxial rotation. The inner keyway at the other end of the steering column tube 2 is connected to the outer keyway on the shaft of the road feel motor 3 through a flat key, so that the road feel motor 3 can accurately receive steering wheel angle and steering wheel torque information. The road feel motor 3 and the road feel motor controller 4 are both fixed on the motor bracket 6.

[0069] The road sensing control device 51 includes:

[0070] The signal receiving module is used to acquire steering wheel angle signal, steering wheel speed signal, and steering wheel torque signal, as well as to collect chassis signals to obtain vehicle speed signal and front wheel angle signal. The steering wheel torque signal is filtered out for noise using a Kalman filter, and the steering wheel angle signal and steering wheel speed signal are filtered out for noise using a low-pass filter. All signals are then input to the initialization module.

[0071] The initialization module is used to convert the absolute position of the steering wheel into a relative position based on the steering wheel angle signal, and to calculate the initial return torque based on the relative position to return the steering wheel to center.

[0072] The road feel control algorithm module calculates the road feel feedback torque based on the resistance torque, soft limit torque, compensation torque, and assist torque, and feeds this feedback torque back to the road feel motor controller 4. The road feel feedback torque is the sum of the resistance torque, soft limit torque, compensation torque, and assist torque, i.e., T. h =T z +T lim +T c +T assis T h T represents the road feel feedback torque. z T represents the resistance torque. lim T represents the soft limiting torque. c T represents the compensating torque. assis Indicates the assist torque;

[0073] The fault detection module monitors whether the CAN signal, steering wheel angle signal, steering wheel speed signal, and road feel torque are within the set range. If they are not within the set range, the output of the road feel motor controller 4 is immediately interrupted to ensure system operation safety, and the cause of the fault is determined according to the fault handling logic. The steering wheel angle signal is the steering wheel rotation angle, ranging from -540° to 540°; the steering wheel speed signal is the angular velocity of the steering wheel rotation, ranging from -1000° / s to 1000° / s; and the steering wheel torque ranges from -10 N·m to 10 N·m.

[0074] The road feel control algorithm module includes:

[0075] The drag torque unit is used to calculate the drag torque based on the collected chassis signals and vehicle parameters;

[0076] The soft limit torque unit is used to calculate the soft limit torque based on the steering wheel angle signal and the angle at which the steering wheel is turned to the left or right limit position;

[0077] The compensation torque unit is used to calculate the compensation torque based on friction compensation, damping compensation, inertia compensation, and self-correction compensation.

[0078] The assist torque unit is used to obtain the assist torque by looking up a map table, which is obtained based on experimental calibration.

[0079] In the resistance torque unit, the formula for calculating the resistance torque is shown in Equation I:

[0080]

[0081] In formula I, T z The values ​​represent the drag torque (N·m), m represents the total mass of the vehicle (kg), v represents the vehicle speed (m / s), l represents the wheelbase (m), the wheelbase is the distance between the front and rear axles, δ represents the front wheel rotation angle (rad), and ξ represents the tire trail (m). V The distance from the center of mass to the front axle is expressed in meters (m). h This represents the distance from the center of mass to the rear axle, in meters (m). (C) αH Represents the rear wheel lateral stiffness, in N / rad, C αV The front wheel lateral stiffness is represented by N / rad, Q by wheel load in kg, β′ by kingpin inclination angle in rad, and D by kingpin displacement in meters (m). r G1 represents the stationary resistance torque, f represents the coefficient of friction between the tire and the ground, G1 represents the steering axle load in N, and p represents the tire pressure in kPa.

[0082] The vehicle's total mass, wheelbase, tire trail, distance from center of gravity to front axle, distance from center of gravity to rear axle, rear wheel lateral stiffness, front wheel lateral stiffness, wheel load, kingpin inclination angle, kingpin displacement, coefficient of friction between tire and ground, steering axle load, and tire pressure are all vehicle parameters, all obtained through experimental calibration.

[0083] In the soft-limit torque element, the calculation formula for the soft-limit torque is shown in Equation II:

[0084]

[0085] In Equation II, T lim This represents the soft-limiting torque, in N·m, θ sw The angle of rotation of the steering wheel is expressed in rad, θ. lim This indicates the angle of rotation of the steering wheel to its left and right extreme positions, measured in rad (k). lim This represents the limit control torque coefficient, with units of N·m / rad. 2 .

[0086] In the compensation torque unit, the calculation formula for the compensation torque is shown in Equation III:

[0087] Tc =T f +T d +T i +T a (III)

[0088] In Equation III, T c T represents the compensating torque. f T represents the friction compensation torque. d T represents the damping compensation torque. i T represents the inertial compensation torque. a Indicates the corrective compensation torque;

[0089] The formula for calculating the friction compensation torque is shown in Equation IV:

[0090]

[0091] In equation IV, T f This represents the friction compensation torque, expressed in N·m, α. f The curve ascent coefficient, This represents the angular velocity of the steering wheel rotation, measured in rad / s, kJ / s. f This represents the friction compensation coefficient, with units of N·m;

[0092] The formula for calculating the damping compensation torque is shown in Equation V:

[0093]

[0094] In formula V, T d This represents the damping compensation torque, expressed in N·m. This represents the angular velocity of the steering wheel rotation, measured in rad / s, kJ / s. d This represents the damping compensation coefficient, with units of N·m / (rad / s);

[0095] The formula for calculating the inertial compensation torque is shown in Equation VI:

[0096]

[0097] In equation VI, T i This represents the inertial compensation torque, with units of N·m. This represents the angular acceleration of the steering wheel, measured in rad / s². 2 k i This represents the inertia compensation coefficient, with units of N·m / (rad / s). 2 );

[0098] The formula for calculating the corrective compensation torque is shown in Equation VII:

[0099] T a=k a θ sw (VII)

[0100] In equation VII, T a This represents the aligning compensation torque, in N·m, θ sw This indicates the steering wheel rotation angle, measured in rad (k). a This represents the positive correction compensation coefficient, with units of N·m / rad.

[0101] Among them, the limit control torque coefficient, curve ascent coefficient, friction compensation coefficient, damping compensation coefficient, inertia compensation coefficient, and alignment compensation coefficient were all obtained by experimental calibration.

[0102] Example 2

[0103] like Figure 1 and Figure 2 As shown, a control method based on the road sense simulation system in Embodiment 1 includes:

[0104] After the road sense simulation system is powered on, the driver turns the steering wheel 1, and the steering wheel angle signal and steering wheel torque signal are transmitted to the road sense motor 3 through the steering column tube 2. The road sense motor controller 4 processes the steering wheel angle signal obtained from the road sense motor 3 to obtain the steering wheel speed signal, and then performs noise filtering on the steering wheel angle signal, steering wheel speed signal and steering wheel torque signal and transmits them to the chassis domain controller 5 through the CAN line.

[0105] In the chassis domain controller 5, the road feel control device 51 calculates the initial return torque by obtaining the steering wheel angle signal from the road feel motor controller 4, and transmits it to the road feel motor controller 4. The road feel motor controller 4 controls the road feel motor 3 to generate the return torque, so that the steering wheel 1 returns to center. Then, the road feel control device 51 calculates the road feel feedback torque by obtaining the steering wheel angle signal, steering wheel speed signal, and steering wheel torque signal from the road feel motor controller 4, as well as the vehicle speed signal and front wheel angle signal from the chassis domain controller 5, and feeds the road feel feedback torque back to the road feel motor controller 4. The road feel motor controller 4 controls the road feel motor 3 to generate the road feel feedback torque, and transmits it to the steering wheel 1 through the steering column tube 2, so as to realize the driver's perception of road conditions and vehicle status.

[0106] The road sense control device 51 includes a signal receiving module, an initialization module, a road sense control algorithm module, and a fault detection module. First, the signal receiving module receives steering wheel angle, steering wheel speed, and steering wheel torque signals from the road sense motor controller 4, and vehicle speed and front wheel angle signals from the chassis domain controller 5. It uses a Kalman filter to filter noise from the steering wheel torque signal and a low-pass filter to filter noise from the steering wheel angle and steering wheel speed signals, then transmits all signals to the initialization module. Second, after powering on, the initialization module first checks whether the received steering wheel angle, steering wheel speed, and steering wheel torque signals are within a set range. If they are not within the set range, it immediately stops the program and reports an error. If they are within the set range, it jumps to the next step, calculates the relative position of the steering wheel in one revolution based on the received steering wheel angle signal, and calculates the initialization parameters based on the relative position of the steering wheel. The system generates a return torque and transmits it to the road feel motor controller 4. The road feel motor controller 4 controls the road feel motor 3 to generate a return torque, causing the steering wheel 1 to automatically return to center. After the steering wheel 1 returns to center, the initialization module exits. Third, the road feel control algorithm module is started. The resistance torque, soft limit torque, compensation torque, and assist torque are calculated by the resistance torque unit, soft limit torque, compensation torque, and assist torque unit in the road feel control algorithm module, respectively. The resistance torque, soft limit torque, compensation torque, and assist torque are added together to obtain the road feel feedback torque, and the road feel feedback torque is transmitted to the road feel motor controller 4 through the CAN line. During program operation, the fault detection module constantly monitors whether the CAN signal, steering wheel angle signal, steering wheel speed signal, and steering wheel torque signal are within the set range. If there is an abnormal situation, the output of the road feel motor controller 4 is immediately interrupted to ensure the safety of system operation. At the same time, the cause of the fault is determined according to the fault handling logic.

[0107] In summary, the road feel simulation system and control method of the present invention transmit steering wheel angle and steering wheel torque signals to the road feel motor controller via the steering column tube and the road feel motor. The road feel motor controller processes the steering wheel angle signal to obtain the steering wheel speed signal and transmits the steering wheel angle signal, steering wheel speed signal, and steering wheel torque signal to the chassis domain controller. The road feel control device in the chassis domain controller calculates the steering wheel angle signal, steering wheel speed signal, and steering wheel torque signal to accurately obtain the road feel feedback torque reflecting the road surface conditions and vehicle driving state, and feeds the road feel feedback torque back to the road feel motor controller. The road feel motor controller controls the road feel motor to generate the road feel feedback torque, which is transmitted to the steering wheel via the steering column tube, enabling the driver to accurately perceive the road surface conditions and vehicle state. This compensates for the torque transmission problem caused by the lack of mechanical structure between the steering wheel and steering wheels in steer-by-wire systems, and has promotional application value in the field of automotive steer-by-wire technology.

[0108] The above embodiments are merely preferred embodiments provided to fully illustrate the present invention, and the scope of protection of the present invention is not limited thereto. Equivalent substitutions or modifications made by those skilled in the art based on the present invention are all within the scope of protection of the present invention.

Claims

1. A road feel simulation system, characterized in that, It includes a steering wheel, a steering column tube, a road feeler motor, a road feeler motor controller, and a chassis domain controller connected in sequence, wherein the chassis domain controller is equipped with a road feeler control device; When the steering wheel is turned, the steering wheel angle signal and steering wheel torque signal are transmitted to the road sensor motor controller through the steering column tube and the road sensor motor. The road sensor motor controller processes the steering wheel angle signal to obtain the steering wheel speed signal, and then transmits the steering wheel angle signal, steering wheel speed signal, and steering wheel torque signal to the chassis domain controller. The road feel control device in the chassis domain controller calculates the road feel feedback torque through the steering wheel angle signal, steering wheel speed signal and steering wheel torque signal, and feeds the road feel feedback torque back to the road feel motor controller; The road feel motor controller controls the road feel motor to generate road feel feedback torque, which is transmitted to the steering wheel through the steering column tube, allowing the driver to perceive the road conditions and vehicle status. The road sensing control device includes: The signal receiving module is used to acquire steering wheel angle signal, steering wheel speed signal, and steering wheel torque signal, as well as to collect chassis signals to obtain vehicle speed signal and front wheel angle signal; The initialization module is used to convert the absolute position of the steering wheel into a relative position based on the steering wheel angle signal, calculate the initial return torque based on the relative position, and feed the initial return torque back to the road sensor motor controller. The road sensor motor controller controls the road sensor motor to generate the initial return torque, which is then transmitted to the steering wheel through the steering column tube to make the steering wheel return to center. The road feel control algorithm module is used to calculate the road feel feedback torque through the resistance torque, soft limit torque, compensation torque and assist torque, and feed the road feel feedback torque back to the road feel motor controller. The road feel feedback torque is the sum of the resistance torque, soft limit torque, compensation torque and assist torque. The formula for calculating the compensating torque is shown in Equation III: T c =T f +T d +T i +T a (Ⅲ) In formula III, T c represents a compensating moment, T f represents a friction compensating moment, T d represents a damping compensating moment, T i represents an inertia compensating moment, T a represents a return compensating moment; The formula for calculating the friction compensation torque is shown in Equation IV: （Ⅳ） In Equation IV, T f a represents the friction compensation torque. f The curve ascent coefficient, k represents the angular velocity of the steering wheel rotation. f Indicates the friction compensation coefficient; The formula for calculating the damping compensation torque is shown in Equation V: （Ⅴ） In Equation V, T d Indicates the damping compensation torque. k represents the angular velocity of the steering wheel rotation. d Indicates the damping compensation coefficient; The formula for calculating the inertial compensation torque is shown in Equation VI: （Ⅵ） In Equation VI, T i Indicates the inertial compensation torque. k represents the angular acceleration of the steering wheel. i Indicates the inertia compensation coefficient; The formula for calculating the corrective compensation torque is shown in Equation VII: （Ⅶ） In formula VII, T a This indicates the corrective compensation torque. k represents the steering wheel rotation angle. a This represents the positive correction compensation coefficient.

2. The road feel simulation system according to claim 1, characterized in that, The road feel control algorithm module includes: The drag torque unit is used to calculate the drag torque based on the collected chassis signals and vehicle parameters; The soft limit torque unit is used to calculate the soft limit torque based on the steering wheel angle signal and the angle at which the steering wheel is turned to the left or right limit position; The compensation torque unit is used to calculate the compensation torque based on friction compensation, damping compensation, inertia compensation, and self-correction compensation. The assist torque unit is used to obtain the assist torque by looking up a table.

3. The road feel simulation system according to claim 2, characterized in that, In the aforementioned resistance torque unit, the formula for calculating the resistance torque is shown in Equation I: （Ⅰ） In Equation I, T z The value represents the drag torque, m represents the total mass of the vehicle, v represents the vehicle speed, and l represents the wheelbase. Indicates the rotation angle of the front wheels. Indicates the front tire trail, l V The distance l represents the distance from the center of mass to the front axle. h C represents the distance from the center of mass to the rear axle. aH C represents the rear wheel lateral stiffness. aV This indicates the front wheel lateral stiffness, and Q represents the wheel load of a single tire. The front wheel kingpin inclination angle is represented by , D represents the front wheel kingpin displacement, f represents the coefficient of friction between the tire and the ground, G1 represents the front axle load, and p represents the tire pressure of a single tire.

4. The road feel simulation system according to claim 2, characterized in that, In the soft-limiting torque unit, the calculation formula for the soft-limiting torque is shown in Equation II: （Ⅱ） In Formula II, T lim Indicates soft limit torque. Indicates the angle of rotation of the steering wheel. k represents the angle of rotation of the steering wheel to its left and right extreme positions. lim This indicates the limit control torque coefficient.

5. The road feel simulation system according to claim 1, characterized in that, The road feel control device also includes a fault detection module, used to monitor whether the steering wheel angle signal, steering wheel speed signal and steering wheel torque signal are within the set range.

6. The road feel simulation system according to claim 1, characterized in that, One end of the steering column tube is splined to the steering wheel, and the other end is keyed to the motor shaft of the road feel motor.

7. A control method based on the road feel simulation system according to any one of claims 1 to 6, characterized in that, include: The road sensor motor controller processes the steering wheel angle signal obtained from the road sensor motor to obtain the steering wheel speed signal. Then, it performs noise filtering on the steering wheel angle signal, steering wheel speed signal, and steering wheel torque signal and transmits them to the chassis domain controller. The road feel control device in the chassis domain controller calculates the initial return torque by obtaining the steering wheel angle signal from the road feel motor controller and transmits it to the road feel motor controller. The road feel motor controller controls the road feel motor to generate the return torque, so that the steering wheel returns to center. Then, the road feel control device calculates the road feel feedback torque by obtaining the steering wheel angle signal, steering wheel speed signal, and steering wheel torque signal from the road feel motor controller, as well as the vehicle speed signal and front wheel angle signal from the chassis domain controller, and feeds the road feel feedback torque back to the road feel motor controller. The road feel motor controller controls the road feel motor to generate the road feel feedback torque and transmits it to the steering wheel through the steering column tube, so as to enable the driver to perceive the road conditions and vehicle status.

8. The control method for the road feel simulation system according to claim 7, characterized in that, The road sense control device includes a signal receiving module, an initialization module, a road sense control algorithm module, and a fault detection module; The signal receiving module obtains steering wheel angle signal, steering wheel speed signal, and steering wheel torque signal from the road sensor motor controller, as well as vehicle speed signal and front wheel angle signal from the chassis domain controller. The signal receiving module filters out noise from the steering wheel angle signal, steering wheel speed signal, and steering wheel torque signal before transmitting them to the initialization module. The initialization module first determines whether the received steering wheel angle signal, steering wheel speed signal, and steering wheel torque signal are within the set range. If they are within the set range, it calculates the relative position of the steering wheel in this revolution based on the received steering wheel angle signal, calculates the initial return torque based on the relative position of the steering wheel in this revolution, and transmits it to the road sensor motor controller. The road sensor motor controller controls the road sensor motor to generate the return torque, so that the steering wheel automatically returns to center. The road feel control algorithm module calculates the resistance torque, soft limit torque, compensation torque, and assist torque through the resistance torque unit, soft limit torque unit, compensation torque unit, and assist torque unit in the road feel control algorithm module, respectively. The resistance torque, soft limit torque, compensation torque, and assist torque are added together to obtain the road feel feedback torque, and the road feel feedback torque is transmitted to the road feel motor controller through the CAN line. The fault detection module monitors whether the CAN signal, steering wheel angle signal, steering wheel speed signal, and steering wheel torque signal are within the set range. If they are not within the set range, the output of the road sensor motor controller is immediately interrupted.

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