Independent Wheel Steering for Rear Wheel Unevenness Avoidance
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Solution Overview
Problem
Existing steering systems fail to maintain vehicle stability by preventing the rear wheel from passing road surface unevenness after the front wheel does so, leading to instability.
Innovation Solution
A steering system with independent control of front and rear wheels, employing rear wheel avoidance control to set a rear-wheel avoidance side slip angle and adjust steering angles to prevent the rear wheel from following the front wheel's path over uneven terrain, using methods like ZMP detection for lift detection and target line travel control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the front wheel steers to pass unevenness, then the front wheel can traverse the obstacle, but the rear wheel follows the same path and passes the unevenness causing vehicle instability
Solution Approach 1:
The steering system is divided into independent front wheel steering device and rear wheel steering device, each controlled separately. The controller independently determines steering angles for front and rear wheels, allowing the rear wheel to take a different path than the front wheel when encountering unevenness, thus maintaining vehicle stability while enabling the front wheel to traverse obstacles.
2Device complexity
If the rear wheel follows the front wheel's path, then the steering system is simple, but the rear wheel passes unevenness causing lift and instability
Solution Approach 1:
The steering system dynamically adjusts the rear wheel's steering angle based on real-time detection of front wheel encounters with unevenness. When the front wheel detects unevenness, the controller calculates an adjusted rear wheel steering angle that diverges from the front wheel's path, preventing the rear wheel from encountering the same obstacle and maintaining vehicle stability during dynamic travel conditions.
3Stability of the object's composition
If independent steering control is implemented, then the rear wheel can avoid unevenness, but the control system becomes more complex
Solution Approach 1:
The steering system incorporates a detection device that monitors the front wheel's encounter with unevenness and provides feedback to the controller. Based on this feedback, the controller calculates an adjusted rear wheel steering angle that prevents the rear wheel from following the front wheel's path. This feedback mechanism enables stable vehicle operation while managing control system complexity through intelligent, real-time adjustments.
Data Source
AI summary
A steering system for a vehicle includes: a front wheel steering device configured to steer a front wheel, a rear wheel steering device configured to steer a rear wheel, and a controller configured to control the front wheel steering device and the rear wheel steering device such that the front wheel and the rear wheel are steerable independently of each other. When the front wheel passes unevenness, the controller executes a rear wheel avoidance control to avoid the rear wheel from passing the unevenness. In the rear wheel avoidance control, the controller determines a rear-wheel avoidance side slip angle, which is a vehicle center-of-gravity point side slip angle to be realized, and determines a target steering angle, which is a steering angle to which each of the front wheel and the rear wheel is to be steered, based on the rear-wheel avoidance side slip angle.