Steering Torque Control Device for Natural Switch-Back Feel
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Solution Overview
Problem
Existing control devices for steering members in vehicles often result in unnatural feelings for drivers due to inadequate application of assist torque or reaction force torque, particularly during switch-back states and low lateral acceleration conditions.
Innovation Solution
A control device that calculates and corrects the control amount for assist or reaction force torque based on steering torque, steering angle speed, yaw rate, and lateral acceleration to enhance the reaction force applied during switch-back states, ensuring a more natural steering experience.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If assist torque or reaction force torque is applied to the steering member using conventional control methods, then steering assistance is provided to the driver, but unnatural feelings occur during switch-back states and low lateral acceleration conditions
Solution Approach 1:
The control device dynamically adjusts the reaction force torque magnitude based on detected steering parameters (steering angle, steering angle speed, lateral acceleration). When switch-back state is detected with high steering angle speed and low lateral acceleration, the system increases reaction force torque to compensate for torque loss, thereby maintaining natural steering feel across varying operating conditions
Solution Approach 2:
The control device continuously monitors steering angle, steering angle speed, and lateral acceleration to detect switch-back states. Based on this feedback, the system dynamically corrects the control amount for reaction force torque application, ensuring appropriate torque is provided during transient steering maneuvers while maintaining stability during normal operation
2Reliability
If the control amount for reaction force torque is increased to prevent torque loss during switch-back states, then steering responsiveness is improved, but steering stability may deteriorate under normal conditions
Solution Approach 1:
The control device dynamically adjusts the reaction force torque magnitude based on real-time detection of steering conditions. During normal steady-state steering, conventional torque is applied maintaining stability. When switch-back state is detected (high steering angle speed, low lateral acceleration), the system dynamically increases torque to prevent loss, then returns to normal operation, thereby maintaining both stability and responsiveness
Solution Approach 2:
The control device applies different torque characteristics to different steering conditions. Normal steering operations receive standard assist torque for stability, while switch-back states receive enhanced reaction force torque for responsiveness. This localized adaptation of torque quality based on operational context resolves the contradiction between stability and responsiveness
Data Source
AI summary
Assist torque or reaction force torque with little unnatural feeling to a driver is applied. An ECU includes: a control amount calculation section that calculates a control amount for controlling magnitude of the assist torque or the reaction force torque with reference to steering torque applied to a steering member; and a control amount correction section that corrects the control amount calculated by the control amount calculation section with reference to a lateral G of a vehicle body, a steering angle of the steering member, and a steering angle speed of the steering member.