CN-116674569-B - Feedforward correction method for distributed driving electric automobile tire force fluctuation

Abstract

The invention discloses a feedforward correction method for distributed driving of electric automobile tire force fluctuation, which is designed to realize notch for given torque near the inherent frequency of wheel torsional vibration according to a tire torsional vibration relative damping coefficient calculation formula, so as to realize tire force fluctuation suppression; the real-time calculation method of the relative damping coefficient of the torsional vibration of the tire is designed and realized according to the condition that the relative damping coefficient of the torsional vibration of the tire changes along with the wheel speed and the longitudinal sliding stiffness, the sliding rate derivative and the longitudinal sliding stiffness are calculated through obtaining the wheel speed, the vehicle speed and the motor output torque signal in real time, the actual relative damping coefficient of the torsional vibration of the tire is calculated on line, and whether feedforward correction is involved in the adjustment of the torque of a given motor or not is determined according to the absolute value of the difference value between the actual relative damping coefficient and the target relative damping coefficient, so that the dynamic quality and the driving comfort of the tire force response during the acceleration of a distributed driving automobile are improved.

Inventors

• LU JIANWEI
• ZHU YINGJIE
• LI JIALIN
• YE SHENGYONG
• SHI LEI
• XU RUIMING
• WEI DAOGAO
• WU BOFU

Assignees

• 合肥工业大学

Dates

Publication Date

20260505

Application Date

20230630

Claims (3)

1. 1. The feedforward correction method for the distributed driving electric automobile tire force fluctuation is characterized by being applied to a distributed scene consisting of an electronic stability control system ESC, a CAN bus, a motor controller and a wheel torsional vibration system, and comprising the following steps of: Step 1, outputting a current k-moment vehicle speed signal by an electronic stability control system ESC And transmitted to a motor controller through a CAN bus, wherein the motor controller is used for controlling the motor according to the current vehicle speed signal at the moment k Subtracting the vehicle speed signal at time k-1 Then dividing the time by the sampling time T 1 to obtain the derivative signal of the current k moment vehicle speed Step 2, utilizing the motor rotation speed signal at the current k moment And the transmission ratio i of the speed reducer calculates a wheel speed signal omega k at the current k moment, subtracts a wheel speed signal omega k-1 at the k-1 moment from the wheel speed signal omega k , and divides the subtracted wheel speed signal omega k-1 by a sampling time T 2 to obtain a wheel speed derivative signal at the current k moment Step 3, calculating and obtaining a slip rate signal at the current k moment Calculating derivative signal of slip rate at current k moment Wherein r e represents the effective rolling radius of the wheel; step 4, outputting torque according to the current motor at the moment k And the transmission ratio i of the speed reducer, calculating the torque of the wheel end at the current moment k Thereby calculating the longitudinal tire force at the current k moment Wherein J is the moment of inertia of the wheel, and the tire force signal at the current moment k is obtained Subtracting tire force signal at time k-1 Dividing by the sampling time T 3 to obtain a derivative signal of the longitudinal tire force at the current k time Step 5, calculating the longitudinal sliding rigidity at the current k moment Step 6, calculating the relative damping coefficient of the tire torsional vibration system at the current k moment Wherein C Fx represents carcass longitudinal stiffness; is a nominal inertial parameter, and M is the dynamic load of the distributed driving unit; Step 7, calculating the difference value of the current k moment Wherein ζ a represents the target relative damping coefficient; If delta is larger than epsilon, the transfer function between the given torque and the feedforward corrector after the Laplace transformation is carried out Multiplying, and then carrying out Laplace inverse transformation on the product to obtain the torque after feedforward correction and outputting the torque to a wheel end; if delta < epsilon, then the given torque is directly output to the wheel end, wherein epsilon represents a threshold value, epsilon (0, 0.3), s is a complex variable, and omega n is the natural angular frequency of the torsional vibration of the wheel.
2. 2. An electronic device comprising a memory and a processor, wherein the memory is configured to store a program that supports the processor to perform the feedforward correction method of claim 1, the processor being configured to execute the program stored in the memory.
3. 3. A computer readable storage medium having a computer program stored thereon, characterized in that the computer program when run by a processor performs the steps of the feedforward correction method of claim 1.

Description

Feedforward correction method for distributed driving electric automobile tire force fluctuation Technical Field The invention relates to the field of electric automobiles, in particular to a method for inhibiting tire force fluctuation of a distributed driving electric automobile. Background The distributed driving electric automobile has the characteristics of short driving chain, high transmission efficiency, compact structure, easiness in realizing chassis modularized design and the like, and becomes one of important development directions of the electric automobile, a wheel rim/hub motor is directly connected with wheels through a reduction gear, a transmission shaft, a driving axle, a half shaft and other complex mechanical transmission devices are not needed, on one hand, the torque fluctuation risk caused by elastic deformation of the transmission device structure can be effectively avoided, on the other hand, the problem of automobile shake is highlighted due to fluctuation of acting force between the tires and the road surface caused by dynamic deformation of the tires, the response bandwidth of the motor is high, the delay is short, the output torque can be subjected to instant jump (such as an automobile quick starting stage), torsional vibration is generated by the wheels under the excitation of the transient driving torque, the underdamping vibration is further caused by the acting force of the tires-road surface, the vibrating tire-road surface contact force can deteriorate the dynamic quality of the whole automobile response and reduce the working performance and service life of the wheel rim/hub motor, and on the other hand, the whole automobile fluctuation is caused by the transmission of the suspension to the automobile body and driving comfort is reduced. Disclosure of Invention In order to inhibit the fluctuation of tire-road surface acting force caused by dynamic deformation of wheels when the motor outputs torque transient, the invention provides a feedforward correction method of the tire force fluctuation of the distributed driving electric automobile so as to inhibit the fluctuation of tire-road surface acting force, thereby improving the force response quality of the distributed driving electric automobile, further improving the driving comfort and the working performance and the service life of a motor driving system. In order to solve the technical problems, the technical scheme adopted by the invention comprises the following steps: The invention relates to a feedforward correction method for distributed driving electric automobile tire force fluctuation, which is characterized by being applied to a distributed scene consisting of an electronic stability control system ESC, a CAN bus, a motor controller and a wheel torsional vibration system, and comprising the following steps: Step 1, outputting a current k-moment vehicle speed signal by an electronic stability control system ESC And transmitted to a motor controller through a CAN bus, wherein the motor controller is used for controlling the motor according to the current vehicle speed signal at the moment kSubtracting the vehicle speed signal at time k-1After that, divide by the sampling timeThereby obtaining derivative signals of the current k moment vehicle speed; Step 2, utilizing the motor rotation speed signal at the current k momentAnd speed reducer transmission ratioCalculating wheel speed signal at current k momentAnd then the wheel speed signal is transmittedSubtracting the wheel speed signal at time k-1After dividing by the sampling timeObtaining wheel speed derivative signal at current k moment; Step 3, calculating and obtaining a slip rate signal at the current k momentCalculating derivative signal of slip rate at current k timeWherein, the method comprises the steps of,Representing the effective rolling radius of the wheel; step 4, outputting torque according to the current motor at the moment k And speed reducer transmission ratioCalculating the torque of the wheel end at the current moment kThereby calculating the longitudinal tire force at the current k momentWherein, the method comprises the steps of,The moment of inertia of the wheels; tyre force signal at current k momentSubtracting tire force signal at time k-1After dividing by the sampling timeThereby obtaining derivative signal of longitudinal tyre force at current k moment; Step 5, calculating the longitudinal sliding rigidity at the current k moment; Step 6, calculating the relative damping coefficient of the tire torsional vibration system at the current k moment, wherein,Represents the carcass longitudinal stiffness; is a nominal inertial parameter, and ;Dynamic loading for a distributed drive unit; Step 7, calculating the difference value of the current k moment , wherein,Representing the target relative damping coefficient; If it is Transfer function with feedforward corrector after Laplace transformation of given torqueMultiplying, and then carryi