Steering Control Device With Gradual Torque Reduction for Stops
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Solution Overview
Problem
Existing steering control systems in vehicles face issues with sudden power cutoff causing twisting and vibration of turning tires and steering members during vehicle stops, leading to reduced component lifespan and discomfort.
Innovation Solution
A steering control device that gradually reduces the output torque of steering and turning actuators before power cutoff, linking the control of steering and turning angles to minimize sudden twists and vibrations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of time
If power is cut off suddenly during vehicle stop, then stopping time is reduced, but twisting and vibration of turning tires and steering members occurs
Solution Approach 1:
The system performs preliminary action by gradually reducing the output torque of the steering actuator before cutting off power. The steering control unit decreases the steering output torque in a gradual manner during the stop process, and the turning control unit decreases the turning output torque gradually before power cutoff. This preliminary gradual reduction prevents sudden twisting and vibration when power is cut off, while still achieving timely vehicle stop.
2Object-affected harmful factors
If steering actuator output torque is reduced gradually, then vibration is suppressed, but stopping process becomes longer
Solution Approach 1:
The system applies partial action by implementing gradual torque reduction only during the critical deceleration phase before power cutoff, rather than maintaining full torque throughout the entire stopping process. The steering control unit and turning control unit gradually reduce torque during the stop process, then cut power completely when appropriate. This partial gradual reduction suppresses vibration during the critical phase while limiting the overall stopping time extension.
3Speed
If turning output torque is cut off suddenly, then response speed is improved, but component lifespan is reduced
Solution Approach 1:
The turning control unit performs preliminary action by gradually reducing the turning output torque before complete power cutoff. This gradual reduction prepares the turning tire and associated components for the upcoming power cutoff, preventing sudden stress and twisting that would reduce component lifespan. After the gradual reduction phase, power is cut off completely to maintain responsive stopping performance.
4Stability of the object's composition
If linked control of steering and turning angles is maintained during stop, then coordination is improved, but control complexity increases
Solution Approach 1:
The system merges the control of steering and turning actuators through the steering control device. The steering control unit controls the steering output torque and the turning control unit controls the turning output torque, with both units coordinated during the gradual reduction phase. This merging approach maintains steering-turning coordination during the stop process while using a unified control device to manage both actuators, preventing excessive complexity multiplication.
Data Source
AI summary
A steering control device includes a steering control unit configured to control an actual steering angle of the steering member by controlling a steering output torque output from the steering actuator, and a turning control unit configured to control an actual turning angle of the turning tire by controlling a turning output torque output from the turning actuator. The turning control unit is configured to perform a gradual reduction control to gradually decrease the turning output torque during a linked control in which the steering control unit controls the actual steering angle in conjunction with the actual turning angle in response to a stop instruction. The turning control unit and the steering control unit are configured to cut energization to the turning actuator and the steering actuator after the gradual reduction control.