Steering Control Device Adjusting Reaction Force Proportions
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Solution Overview
Problem
Existing steering control devices fail to effectively communicate the road surface state to the driver through the steering reaction force, leading to discomfort and a mismatch between perceived and actual responses, especially on low-friction roads where lateral acceleration is reduced.
Innovation Solution
A steering control device that adjusts the proportions of two reaction force components based on the difference between the target and actual rotational angles, increasing the proportion of the second reaction force component when the vehicle is on a low-friction road to enhance the sense of integrity and decrease the sense of rigidity, allowing the driver to better feel the road surface state.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If the proportion of the first reaction force component (based on target rotational angle) is increased to enhance sense of rigidity, then steering stability is improved, but the driver cannot properly perceive road surface state especially on low-friction roads
Solution Approach 1:
The control device dynamically adjusts the proportioning between the first reaction force component (sense of rigidity) and the second reaction force component (sense of integrity) based on detected vehicle state and road surface conditions. This dynamic adjustment allows the system to optimize the balance between steering stability and road surface state perception in real-time, resolving the contradiction by making the composition adaptive rather than fixed.
Solution Approach 2:
The control device changes the parameter of reaction force component proportioning based on detected lateral acceleration and vehicle state. By adjusting the proportioning ratio as a controllable parameter, the system can enhance sense of integrity when needed (improving road surface perception) while maintaining sense of rigidity when appropriate, thus resolving the contradiction between stability and information perception.
2Loss of information
If the proportion of the second reaction force component (based on lateral acceleration) is increased to enhance sense of integrity with the vehicle, then road surface state perception is improved, but steering stability is reduced
Solution Approach 1:
The system dynamically adjusts the proportioning between reaction force components based on real-time detection of lateral acceleration and vehicle state. This allows the sense of integrity to be enhanced when road surface perception is needed while maintaining steering stability through appropriate timing and magnitude of adjustment, resolving the contradiction by making the enhancement conditional and adaptive.
Solution Approach 2:
The control device adjusts the proportioning parameter of reaction force components based on detected vehicle state and road surface conditions. By changing this parameter adaptively, the system can enhance sense of integrity (improving road surface perception) while preventing excessive reduction of steering stability through controlled adjustment limits and conditional application.
3Force
If the basic drive torque is decreased to increase steering reaction force, then steering reaction force is enhanced, but steering assist performance is reduced
Solution Approach 1:
The control device segments the spring component of basic drive torque into two distinct components: the first spring component (based on target rotational angle for sense of rigidity) and the second spring component (based on lateral acceleration for sense of integrity). This segmentation allows independent control and proportioning of each component, enabling the system to adjust steering reaction force while maintaining overall steering assist performance by selectively modifying only the necessary portion.
Solution Approach 2:
The control device applies local quality by differentiating the function of each spring component and assigning them different proportioning strategies. The first component maintains steering stability while the second component enhances road surface perception. This local differentiation allows the system to enhance steering reaction force in specific conditions without compromising overall steering assist performance.
Data Source
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AI summary
A steering control device capable of transmitting a road surface state to a driver as a steering reaction force more appropriately is provided. An ideal vehicle model (72) computes first spring reaction force torque (Tsp1 *) based on a target pinion angle (θp *) and second spring reaction force torque (Tsp2 *) based on at least lateral acceleration (LA) as components of a spring component (Tsp *) of a steering assist force. The ideal vehicle model (72) combines the first and second spring reaction force torques (Tsp1 *) and (Tsp2 *) with specified proportions of use to compute the spring component (Tsp *). The ideal vehicle model (72) decides the proportions of use of the first and second spring reaction force torques (Tsp1 *) and (Tsp2 *) on the basis of a distribution gain (Gδsp) set in accordance with the difference value between the first and second spring reaction force torques (Tsp1 *) and (Tsp2 *). The ideal vehicle model (72) increases the proportion of use of the second spring reaction force torque (Tsp2 *) as the difference value between the first and second spring reaction force torques (Tsp1 *) and (Tsp2 *) is increased.