Steer-by-Wire Wheel Decoupling for Redundant Independent Steering
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Solution Overview
Problem
Conventional steer-by-wire steering mechanisms limit the control domain of vehicle wheels, making it difficult to adapt to varying conditions and meet the requirements of electrification and intelligence, and fail to provide independent control of inner and outer wheels, leading to tire wear and stability issues.
Innovation Solution
A steer-by-wire steering mechanism with a redundancy function that allows left and right wheels to be switched between coupling and decoupling states, utilizing electrically controlled clutches to enable independent control and provide redundancy in case of motor failure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a conventional steering mechanism is used, then the structure is simple, but the control domain of wheel angles is limited and cannot be adaptively adjusted
Solution Approach 1:
The steering mechanism is segmented into independent left and right wheel steering systems, each with its own motor and clutch assembly. This allows independent control of each wheel while maintaining the ability to couple them when needed, thereby expanding the control domain without excessive structural complexity.
Solution Approach 2:
The system dynamically switches between coupled and decoupled states through electrically controlled clutches. The coupling state can be adjusted based on operating conditions such as load, tire pressure, and vehicle speed, enabling adaptive control while maintaining a relatively simple base structure.
2Adaptability or versatility
If inner and outer wheels are mechanically coupled, then the structure is simple, but independent control based on control objectives cannot be achieved
Solution Approach 1:
The permanent mechanical coupling between inner and outer wheels is replaced with electrically controlled clutches that can engage or disengage as needed. This substitution allows independent control of each wheel when clutches are disengaged, while maintaining mechanical coupling simplicity when they are engaged, thereby achieving independent control capability without permanently complicating the mechanical structure.
3Adaptability or versatility
If inner and outer wheels are completely mechanically decoupled, then independent control is achieved, but redundancy function is lost
Solution Approach 1:
The system dynamically adjusts the coupling state between wheels based on operational needs and fault conditions. During normal operation, wheels can be independently controlled with clutches disengaged. When a fault is detected or specific driving conditions require it, the clutches can engage to couple the wheels, providing redundancy and ensuring continued safe operation.
Solution Approach 2:
The mechanical coupling mechanism serves as a pre-prepared backup system. Before a complete control system failure occurs, the redundant mechanical coupling path is available to be activated, providing a safety net that ensures the vehicle can still be controlled even if the primary electronic control system fails.
4Adaptability or versatility
If conventional steering trapezoid parameter is used, then the structure is fixed, but tire wear is aggravated due to inability to adapt to actual operating conditions
Solution Approach 1:
The steering mechanism enables dynamic adjustment of wheel angles independently of fixed geometric constraints. The control system can adapt wheel angles based on real-time operating conditions such as load, tire pressure, and vehicle speed, optimizing tire contact and reducing wear while maintaining a relatively simple mechanical structure.
Solution Approach 2:
The system changes steering parameters (wheel angles, coupling state) based on operating conditions. By independently controlling each wheel and adjusting the coupling state, the system can optimize the effective steering trapezoid parameters for current conditions, reducing tire wear without requiring a complex mechanically adjustable steering trapezoid mechanism.
Data Source
Figure 1
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Figure 4~5
AI summary
A steer-by-wire steering mechanism with a safety redundancy function and capable of implementing independent control on steering motions of left and right wheels is provided, including a coupler (1), a steering executing mechanism, and a steering driving mechanism. The steering executing mechanism includes a first steering device (2) and a second steering device (3), and the steering driving mechanism includes a first motor (4) and a second motor (5). With the control on coupling states of wheels and a steering wheel (6-1) by the coupler (1), redundancy control of a steering system can be realized in failure states such as a single-side steering motor failure, a two-side steering motor failure, and a tire burst. The steering mechanism helps ensure driving safety, and can be used in steering systems of vehicles such as an intelligent vehicle, a self-driving vehicle, and a new energy vehicle.