Vehicle Motor Yaw Control for Oversteer and Understeer Handling
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Solution Overview
Problem
Existing vehicle motor control systems do not effectively consider handling performance, such as oversteer or understeer, when determining motor control amounts, leading to inadequate turning responsiveness and stability.
Innovation Solution
A vehicle motor control apparatus and method that calculates a motor control amount based on the vehicle's state, using a processor to determine whether the vehicle is in an over-steer or under-steer state, and adjusts the motor control accordingly by calculating a target yaw moment, incorporating factors like tire force, yaw rate, and slip angles to improve torque control for front and rear wheel motors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If motor control amount is determined without considering handling performance, then device complexity is reduced, but turning responsiveness and stability deteriorate
Solution Approach 1:
The system performs preliminary classification of turning situations into five categories (sharp turn, moderate turn, straight turn, U-turn, 180-degree turn) based on steering angle and steering angle change rate before executing motor control. This preliminary classification enables appropriate torque control to be applied in advance for each turning phase, improving turning stability without requiring complex real-time calculations during execution
Solution Approach 2:
The control system dynamically adjusts motor torque based on the detected turning situation and phase, transitioning between different control modes (driving control, braking control, or no control) depending on the vehicle state. This dynamic adaptation allows the system to optimize handling performance for each specific turning scenario rather than using a fixed control strategy
2Device complexity
If motor control amount is determined without considering handling performance, then calculation complexity is reduced, but turning responsiveness deteriorates
Solution Approach 1:
The turning process is segmented into distinct phases (initial turning phase and subsequent turning phase) based on steering angle change rate thresholds. This segmentation allows the system to apply different control strategies appropriate to each phase, enabling rapid response during initial turning while maintaining stability during subsequent phases
Solution Approach 2:
The system applies different torque control characteristics to front and rear wheel motors based on the specific turning situation and phase. For example, during understeer conditions, the rear motor may receive driving control while the front motor receives braking control, creating localized torque differences that improve overall turning responsiveness without requiring complex global recalculation
3Speed
If torque control is performed for each turning situation, then turning responsiveness is improved, but device complexity increases
Solution Approach 1:
The system changes control parameters (torque magnitude, torque direction, control mode selection) based on detected turning situations and phases. By using predefined thresholds for steering angle and steering angle change rate, the system can switch between different torque control parameters without requiring complex algorithms, thus improving responsiveness while limiting complexity growth
Solution Approach 2:
The control system continuously monitors steering angle, steering angle change rate, and vehicle speed to detect turning situations and phases. This feedback mechanism allows the system to automatically adjust motor torque in response to actual vehicle behavior, improving turning responsiveness while using simple threshold-based detection logic rather than complex predictive models
Data Source
AI summary
A vehicle motor control apparatus includes: a processor configured to determine whether a state of a vehicle is an over-steer state or an under-steer state, to determine a driving control mode or a braking control mode of a motor based on a determination result of the state of the vehicle, to calculate a target yaw moment of based on a tire force by using the over-steer state or the under-steer state, and to determine a motor control amount that follows the target yaw moment; and a storage configured to store data and algorithms driven by the processor.