Rear Wheel Steering Feedback Control for Vehicle Stability
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Solution Overview
Problem
Conventional Rear Wheel Steering (RWS) control methods require time-consuming and experience-dependent tuning, and are prone to instability due to environmental disturbances, lacking an independent stability control function.
Innovation Solution
An apparatus and method for controlling vehicle stability using RWS, comprising a vehicle status reference generator, estimator, and position calculator, which dynamically adjusts wheel base and center of gravity position based on drive mode and sensor data to optimize steering response and stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If feedforward control method is used for RWS, then steering response is improved, but tuning time and complexity increase significantly
Solution Approach 1:
The patent implements a feedback control mechanism that continuously monitors vehicle state (lateral acceleration, yaw rate) and adjusts rear wheel steering angle in real-time. This replaces the open-loop feedforward method with closed-loop control, eliminating the need for extensive manual tuning while maintaining fast steering response. The feedback loop automatically adapts to changing driving conditions without requiring engineer intervention.
Solution Approach 2:
The control system performs self-adjustment by automatically calculating optimal rear wheel steering angles based on real-time vehicle dynamics parameters. The system serves itself by continuously optimizing steering control without external tuning input, eliminating the time-consuming manual calibration process while preserving rapid steering response capabilities.
2Speed
If feedforward control method is used for RWS, then steering response is improved, but vehicle stability under disturbance decreases
Solution Approach 1:
The patent employs feedback control that continuously monitors vehicle lateral acceleration and yaw rate to detect disturbances. When instability is detected, the system automatically adjusts rear wheel steering to counteract the disturbance. This closed-loop approach maintains vehicle stability under varying conditions while preserving fast steering response, unlike the open-loop feedforward method that cannot adapt to unexpected disturbances.
3Manufacturing precision
If experience-dependent tuning is performed for RWS, then control precision is improved, but ease of operation deteriorates
Solution Approach 1:
The control system automatically determines optimal steering parameters by processing real-time vehicle dynamics data. No manual tuning or expert knowledge is required - the system self-configures based on measured vehicle behavior. This eliminates the need for experienced engineers to perform time-consuming adjustments while maintaining high control precision through continuous adaptive optimization.
Solution Approach 2:
The patent replaces manual tuning procedures with automated computational algorithms. Instead of relying on human expertise and iterative mechanical adjustments, the system uses computer-based control algorithms to automatically optimize steering parameters. This substitution of manual processes with automated systems maintains precision while dramatically improving ease of operation.
Data Source
AI summary
An apparatus for controlling vehicle stability based on RWS comprises a vehicle status reference generator generating a reference, which represents a vehicle status, based on a front wheel steer angle, a drive mode, and a sensor signal transmitted from an in-vehicle network, a vehicle status estimator estimating lateral velocity and disturbance, based on front and rear wheel steer angles and the sensor signal transmitted from the in-vehicle network, an RWS target position calculator generating an RWS target position value, based on the reference generated from the vehicle status reference generator, the sensor signal transmitted from the in-vehicle network, the front wheel steer angle, and the lateral velocity and disturbance estimated from the vehicle status estimator, and an RWS position controller generating target motor torque, based on the RWS target position value calculated from the RWS target position calculator and an RWS rack position value.