Rear Wheel Steering Control for Terrain-Adaptive Stability
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Solution Overview
Problem
Four-wheel steering arrangements optimized for road use are not suitable for other terrains, compromising maneuverability and stability.
Innovation Solution
A control system that adjusts rear wheel steering based on mode selection, vehicle speed, terrain conditions, and other factors to optimize maneuverability or stability for different terrains.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If four-wheel steering arrangement is used to enhance road performance, then maneuverability and stability on roads are improved, but suitability for other terrains deteriorates
Solution Approach 1:
The steering system dynamically adjusts rear wheel steering angles based on vehicle speed and terrain conditions. At low speeds, rear wheels steer out of phase with front wheels to enhance maneuverability. At high speeds, rear wheels steer in phase with front wheels to enhance stability. This dynamic adjustment allows the system to adapt to different terrains and operating conditions without requiring multiple fixed steering systems.
Solution Approach 2:
The system changes the steering parameter (rear wheel steering angle) based on vehicle speed and terrain mode. A control means receives signals indicative of vehicle speed and selected mode, then determines a proposed rear wheel steering angle that optimizes performance for the current conditions. This parameter change approach enables the same steering system to perform optimally across diverse terrains from roads to off-road environments.
2Ease of operation
If rear wheels are steered out of phase with front wheels at low speeds, then maneuverability is enhanced, but stability deteriorates
Solution Approach 1:
The steering system dynamically switches between out-of-phase and in-phase rear wheel steering based on vehicle speed. Below a threshold speed, rear wheels are steered out of phase with front wheels to maximize maneuverability for tasks like parking and tight space navigation. Above the threshold speed, rear wheels are steered in phase with front wheels to maximize stability during highway driving. This dynamic switching resolves the contradiction by applying the appropriate steering mode based on real-time speed conditions.
3Stability of the object's composition
If rear wheels are steered in phase with front wheels at high speeds, then stability is enhanced, but maneuverability deteriorates
Solution Approach 1:
The system dynamically adjusts rear wheel steering phase based on vehicle speed conditions. At high speeds above the threshold, rear wheels are steered in phase with front wheels to enhance stability for highway driving. When speed drops below the threshold, the system automatically switches to out-of-phase steering to restore maneuverability. This dynamic adjustment ensures optimal performance across the full speed range without sacrificing either stability or maneuverability.
Data Source
AI summary
An apparatus (104) and a method (2600) for controlling steering of a vehicle (100) of a vehicle (100) are disclosed. The apparatus (104) comprises a device (105) configured to receive a first signal indicative of a requested steering angle and a second signal indicative of a roll angle of the vehicle (100). The device is also configured to determine a proposed steering angle for steerable wheels of the vehicle (100) in dependence on the first signal and to provide an output signal configured to cause steering of the steerable wheels at the proposed steering angle. In dependence on a set of criteria being met, the device (105) is configured to determine the proposed steering angle in dependence on the second signal.