EV Transmission Gear Re-Engagement Using Deformation-Based Torque Control
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Solution Overview
Problem
Electric vehicles experience significant vibration and noise due to gear rattling when the motor output torque changes between positive and negative torque, affecting driving comfort and potentially damaging transmission mechanisms.
Innovation Solution
A motor control method that detects relative deformation between the driving gear and wheel end, determines speed difference values, and adjusts the output torque to perform a tooth approaching operation, reducing speed differences and inertia impacts during gear engagement and disengagement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If regenerative braking is performed in related art, then energy recovery during deceleration is achieved, but the motor is damaged due to excessive current when the vehicle is stopped and the brake pedal is not fully depressed
Solution Approach 1:
The control unit continuously monitors the operation state of the brake pedal and dynamically adjusts the regenerative braking force based on this feedback. When the brake pedal is not fully depressed, the system modulates the regenerative braking to prevent excessive current, thereby protecting the motor while still recovering energy during normal deceleration
Solution Approach 2:
The system dynamically adjusts the regenerative braking force based on real-time detection of brake pedal position and vehicle speed. By making the regenerative braking force variable rather than fixed, the system can optimize energy recovery while preventing motor damage under different operating conditions
2Loss of energy
If regenerative braking is performed in related art, then energy recovery is attempted, but control precision is insufficient leading to uncomfortable vibrations and inaccurate braking force adjustment
Solution Approach 1:
The control unit uses feedback from brake pedal position sensors and vehicle speed sensors to precisely control the regenerative braking force. This closed-loop control enables accurate adjustment of braking force to match driver intent while maintaining smooth operation without vibrations
Solution Approach 2:
The system changes the regenerative braking force parameter based on detected brake pedal operation states and vehicle speed. By dynamically adjusting this parameter, the system achieves precise control over braking force magnitude, eliminating vibrations and ensuring accurate braking response
3Speed
If the brake pedal is designed to be easily pressible for safety, then emergency braking response is improved, but regenerative braking control becomes inaccurate due to insufficient detection of pedal depression degree
Solution Approach 1:
The system implements feedback control by continuously monitoring brake pedal position and using this information to adjust regenerative braking force. This allows the easily pressible pedal to maintain both fast response and accurate control through real-time adjustment based on detected pedal depression degree
Solution Approach 2:
The control unit prepares regenerative braking control parameters in advance based on detected brake pedal operation states. When the driver presses the pedal, the system has already prepared appropriate regenerative braking levels, enabling both rapid response and precise control without requiring complex pedal mechanics
Data Source
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AI summary
The present application belongs to the field of electric vehicle technology and specifically relates to an electric vehicle, a motor control method thereof, an apparatus and a storage medium. The motor control method of the electric vehicle of the present application includes: detecting a relative deformation of a transmission system between a driving gear and a wheel end of a motor; determining a first speed difference value of a first driving gear rotation speed and a first wheel end conversion rotation speed when the relative deformation is a first threshold, where the relative deformation being the first threshold value is used to indicate that the driving gear starts to disengage from a driven gear of the transmission system, the first driving gear rotation speed is a rotation speed of the driving gear at a disengagement moment of the driving gear and the driven gear, and the first wheel end conversion rotation speed is a rotation speed obtained by performing a speed ratio conversion on the wheel end rotation speed of the electric vehicle at the disengagement moment; determining an output torque of the motor according to the first speed difference value; and controlling the driving gear to perform a tooth approaching operation relative to the driven gear according the output torque. Therefore, problems of larger vibration and noise of the motor and the transmission system can be reduced or even avoided.