Steering Feel Control Device Using Dual-Spring Feedback Mechanism
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Solution Overview
Problem
Steer-by-wire systems lack a natural sense of steering feedback and experience a rapid increase in steering feedback torque at specific angles, making it difficult to provide consistent feedback between leftward and rightward steering due to the absence of a mechanical connection structure.
Innovation Solution
A steering feel control device with a pressure member, push block, first and second springs, and a lock device that utilizes a pre-compressed second spring with a smaller spring constant to manage steering feedback torque, ensuring a natural steering feel at initial input and preventing excessive torque increase, while providing uniform feedback between leftward and rightward steering.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single spring is used to provide steering feedback, then the structure is simple, but the spring force must be continuously increased as steering angle increases and consistent feedback torque between leftward and rightward steering is impossible
Solution Approach 1:
The steering feedback mechanism is segmented into two separate springs (first spring and second spring) with different spring constants. The first spring has a larger spring constant for initial steering input, while the second spring has a smaller spring constant for larger steering angles. This segmentation allows each spring to operate in its optimal range, providing consistent feedback torque between leftward and rightward steering without requiring a single overly stiff spring.
Solution Approach 2:
The system changes the spring constant parameter by switching between two different springs based on steering angle. The first spring (larger spring constant) is used for small steering angles to provide natural steering feel, while the second spring (smaller spring constant) is engaged for larger steering angles to prevent excessive torque increase. This parameter change resolves the contradiction between structural simplicity and feedback consistency.
2Force
If spring force is continuously increased to maintain feedback at larger steering angles, then feedback torque is maintained, but the steering feel becomes unnatural and excessive torque increase occurs
Solution Approach 1:
The steering feedback system dynamically switches between two different spring constants based on the steering angle. At initial steering input, the first spring with larger spring constant provides strong feedback for natural steering feel. When steering angle exceeds a threshold, the system transitions to the second spring with smaller spring constant to prevent excessive torque increase. This dynamic adaptation maintains appropriate feedback torque across the full steering range while preserving natural steering feel.
3Ease of operation
If a mechanical connection structure is used, then steering feedback is naturally provided, but the layout freedom is reduced and fuel efficiency decreases
Solution Approach 1:
The patent replaces the traditional mechanical connection structure (universal joint, etc.) with a spring-based feedback mechanism. Instead of relying on mechanical elasticity from a connected structure, the system uses controlled elastic elements (springs) to generate steering feedback torque. This substitution eliminates the need for rigid mechanical connections, thereby increasing layout freedom and reducing weight while still providing natural steering feel through the first and second springs.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The device achieves a natural sense of steering at initial input and prevents rapid feedback torque increase, ensuring consistent steering feedback and restoration torque between leftward and rightward steering by using a combination of first and second springs with different spring constants and a lock device.
Implementation Method 1
a first spring configured to provide elastic restoration force with respect to a rotation direction of the pressure member to enable elastic variation in a rotational displacement between the pressure member and the push block
Implementation Method 2
a second spring configured to provide elastic restoration force with respect to a rotation direction of the push block to enable elastic variation in a rotational displacement when the push block is rotated away from the pressure member
Data Source
AI summary
A steering-feel control device in a steer-by-wire system may include a pressure member for rotating in a predetermined direction or an opposite direction within a rotation path depending on the rotation direction of a steering wheel, a push block rotatably provided in the rotation path of the given or opposite direction, a first elastic member for providing elastic restoration force in the rotation direction of the pressure member for elastic variation in the rotational displacement between the pressure member and the push block, and a second elastic member for providing elastic restoration force in the rotation direction of the push block for elastic variation in the rotational displacement when the push block is rotated away from the pressure member, the second elastic member having an elastic constant smaller than that of the first elastic member and being provided in a pre-compressed state to have elastic force greater than that of the first elastic member.