Motor Torque Control for Drivetrain Backlash Minimization
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Solution Overview
Problem
In motor-driven vehicles, gear backlash and torsion in the drivetrain cause noise and vibration during low-speed reduction and restart, as existing anti-jerk control methods are ineffective due to inaccurate wheel speed detection and lack of drivetrain arrangement torque compensation.
Innovation Solution
A motor torque control method that determines a drivetrain arrangement torque based on vehicle operation state information, including speed and gear changes, to minimize drivetrain backlash and torsion by adding this torque to the required and anti-jerk torques, thereby reducing start impact and noise.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If anti-jerk control is performed using only wheel speed detection, then vibration reduction is achieved during normal operation, but the control becomes ineffective at low speeds due to inaccurate speed detection
Solution Approach 1:
The controller performs preliminary drivetrain arrangement by applying drivetrain arrangement torque before vehicle restart. This preliminary action pre-positions the drivetrain components to minimize backlash and torsion, ensuring smooth operation during restart even when wheel speed detection is inaccurate at low speeds.
Solution Approach 2:
The patent introduces drivetrain arrangement torque as an intermediary control element that bridges the gap between inaccurate wheel speed detection and effective vibration reduction. This intermediary torque component compensates for the limitations of speed sensing by directly managing drivetrain positioning.
2Stability of the object's composition
If motor torque is applied during vehicle stopping, then drivetrain engagement is maintained, but gear backlash and torsion occur causing start impact during restart
Solution Approach 1:
The controller applies drivetrain arrangement torque in the opposite direction to counteract the backlash and torsion caused by motor torque during stopping. This preliminary anti-action prepares the drivetrain by eliminating gaps and reducing torsional stress before restart, preventing start impact.
Solution Approach 2:
The patent dynamically adjusts the drivetrain arrangement torque based on real-time detection of vehicle speed, motor speed, and transmission gear position. This dynamic adjustment ensures the drivetrain remains properly engaged during stopping while simultaneously minimizing backlash and torsion that would cause start impact.
3Object-generated harmful factors
If drivetrain arrangement torque is added to the motor torque command, then drivetrain backlash and torsion are minimized, but the control system complexity increases
Solution Approach 1:
The existing controller is enhanced to perform multiple functions: it continues to execute anti-jerk control based on wheel speed detection while simultaneously implementing drivetrain arrangement control based on vehicle speed, motor speed, and transmission gear position. This multi-functionality reduces the need for separate control systems.
Solution Approach 2:
The patent merges the drivetrain arrangement torque calculation with the existing anti-jerk torque calculation in a unified motor torque command. By combining these control functions into a single integrated system, the patent minimizes additional hardware complexity while achieving reduced drivetrain backlash and torsion.
Data Source
AI summary
A motor torque control method for a motor-driven vehicle is carried out when a vehicle reduces its speed to a low speed or is in a stopped state, gear backlash and torsion of a drivetrain are minimized, and thus impact on the drivetrain which may occur during starting or restarting of a vehicle is minimized. The motor control method includes determining whether vehicle speed is in a speed reducing state less than a set vehicle speed or in a stopped state; determining a required torque command, an anti-jerk torque, and an additional drivetrain arrangement torque for removing drivetrain backlash based on vehicle operation state information when the speed reducing state or the stopped state is determined; and determining a motor torque command by using the required torque command, the anti-jerk torque, and the drivetrain arrangement torque.