Steer-by-Wire Variable Transmission Ratio for Stability
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Solution Overview
Problem
Conventional steer-by-wire steering systems face challenges in reducing maximum steering resistance, leading to higher costs and larger feedback actuators, which also require additional mechanisms to prevent over-steering and maintain directional stability.
Innovation Solution
The system employs a steer-by-wire controller that varies the transmission ratio between the steering wheel angle and the steerable wheel angle, allowing for reduced steering resistance and misalignment compensation, enabling a cost-effective and space-saving design by using a feedback actuator that generates minimal resistance and a mechanical steering wheel angle limiter to prevent over-steering.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If conventional steer-by-wire systems use high-torque feedback actuators to maintain directional stability, then directional stability is improved, but system cost and actuator size increase
Solution Approach 1:
The transmission ratio is made variable rather than fixed. The system dynamically adjusts the transmission ratio between steering wheel angle and steerable wheel angle, allowing the feedback actuator to operate with reduced torque requirements while maintaining directional stability through active control.
Solution Approach 2:
The patent changes the transmission ratio parameter based on steering conditions. By varying this parameter, the system achieves directional stability without requiring a high-torque feedback actuator, thus reducing system cost and actuator size.
2Stability of the object's composition
If mechanical linkage assemblies are used to connect steering wheel to wheels, then mechanical stability is improved, but system complexity and space requirements increase
Solution Approach 1:
The patent replaces traditional mechanical linkage assemblies with an electronic control system. Sensors detect steering wheel angle and steerable wheel angle, and a controller actuates the steerable wheels electronically, eliminating complex mechanical linkages while maintaining stability through control algorithms.
3Device complexity
If feedback actuators generate minimal resistance, then system cost and space are reduced, but steering precision and control accuracy deteriorate
Solution Approach 1:
The system uses feedback from sensors that continuously monitor steering wheel angle and steerable wheel angle. This feedback enables the controller to accurately control the steerable wheels even with a minimal-resistance feedback actuator, maintaining steering precision through active compensation.
Solution Approach 2:
The variable transmission ratio dynamically adapts to steering conditions, allowing the system to maintain control accuracy despite using a feedback actuator with minimal resistance. The dynamic adjustment compensates for the reduced actuator capability.
Data Source
AI summary
Steer-by-wire steering systems for vehicles and related methods are described herein. An example steer-by-wire steering system includes a steering wheel angle sensor to detect a current steering wheel angle (α) of a steering wheel of the motor vehicle, a steering actuator to generate a variable steering torque on a steerable wheel of the motor vehicle, a steering angle sensor to detect a current steering angle (β) of the steerable wheel, and a steer-by-wire controller to process signals from the steering wheel angle sensor and the steering angle sensor and control the steering actuator based on the signals. The steer-by-wire controller is configured to vary a transmission ratio between a change in the steering wheel angle (α) and a change in the steering angle (β).