Rear Wheel Steering Control for Stability
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Solution Overview
Problem
Rear wheel steering systems fail to provide drivers with a quick and accurate response characteristic during sudden steering at high or middle speeds, leading to potential accidents due to reduced steering stability and increased yaw occurrences.
Innovation Solution
A rear wheel steering system that includes a vehicle speed detection unit, steering angle detection unit, pinion angle detection unit, and a control unit to calculate and adjust the steering angle of the rear wheels based on vehicle speed, steering angle, and pinion angle, allowing for dynamic adjustment of the steering point to enhance driver feedback and stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If the rear wheel steering angle is increased to improve steering response during sudden maneuvers, then steering responsiveness is improved, but steering stability deteriorates and excessive steering occurs
Solution Approach 1:
The patent applies dynamics by making the rear wheel steering angle dynamic rather than fixed. The control unit calculates and adjusts the rear wheel steering angle in real-time based on vehicle speed, steering angle, and pinion angle. At different vehicle speeds and steering conditions, the system dynamically modifies the steering angle to optimize both responsiveness and stability, preventing excessive steering while maintaining quick response during sudden maneuvers.
Solution Approach 2:
The patent changes the parameter of rear wheel steering angle based on operating conditions. The control unit receives vehicle speed, steering angle, and pinion angle as inputs, then calculates an optimized rear wheel steering angle that varies with these parameters. This parameter change approach allows the system to achieve fast steering response when needed while maintaining stability during normal operation, resolving the contradiction between responsiveness and stability.
2Ease of operation
If the rear wheel steering point is fixed, then the steering system is simple, but the driver cannot feel quick response during sudden steering at high speed
Solution Approach 1:
The patent implements feedback by having the control unit continuously receive information about vehicle speed, steering angle, and pinion angle, then calculate and adjust the rear wheel steering angle accordingly. This closed-loop feedback system allows the driver to feel quick response during sudden steering maneuvers while the system automatically manages the complexity of the control logic, maintaining ease of operation without requiring the driver to understand the complex calculations occurring behind the scenes.
Solution Approach 2:
The control unit acts as an intermediary between the driver's steering input and the actual rear wheel steering action. It receives the driver's steering angle input and pinion angle information, processes this along with vehicle speed data, and generates an optimized rear wheel steering angle. This intermediary approach improves driver steering feeling during sudden maneuvers while hiding the system complexity from the driver, maintaining ease of operation.
Data Source
AI summary
A rear wheel steering system may include: a vehicle speed detection unit configured to detect a vehicle speed; a steering angle detection unit configured to detect a steering angle based on an operation of a steering wheel; a pinion angle detection unit configured to detect a pinion angle based on an operation of the steering wheel; a rear wheel driving unit configured to steer rear wheels; and a control unit configured to receive the vehicle speed, the steering angle, and the pinion angle from the vehicle speed detection unit, the steering angle detection unit, and the pinion angle detection unit, calculate a target rear wheel steering angle for steering the rear wheels, calculate a final rear wheel steering angle at which a steering point of the rear wheels is adjusted using a steering angle speed, the vehicle speed, and the pinion speed, and operate the rear wheel driving unit.