Steering Angle Offset Control for Smooth Motor Output Recovery
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Solution Overview
Problem
Conventional steering control devices face issues with rapid changes in turning motor output when output restriction conditions are canceled, leading to abnormal sounds and vibrations due to discrepancies between target and real angles.
Innovation Solution
The steering control device incorporates a target rotation angle calculation circuit, offset angle calculation, and feedback control to gradually adapt the real angle to a final target rotation angle, reducing the likelihood of rapid changes in turning motor output by calculating an estimated rotation angle deviation and using proportional control to adjust current supply.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the output restriction of the turning motor is canceled when the output restriction condition is no longer met, then the normal steering function is restored, but the output of the turning motor changes rapidly causing abnormal sound or vibration
Solution Approach 1:
The control device calculates an offset angle based on the discrepancy between target and real angles before canceling the output restriction. This preliminary adjustment of the target rotation angle prevents rapid changes in motor output when the restriction is lifted, thereby avoiding abnormal sounds and vibrations while restoring normal steering function.
2Object-generated harmful factors
If the target rotation angle is adjusted to match the real angle when output restriction is canceled, then rapid changes in motor output are prevented, but the steering response becomes slower
Solution Approach 1:
The control device applies a partial correction by calculating an offset angle that is proportional to the discrepancy between target and real angles, rather than completely eliminating the difference. This partial adjustment prevents rapid motor output changes while still allowing the steering system to respond to driver inputs, balancing vibration reduction with response speed.
Data Source
AI summary
A steering control device includes: a target rotation angle calculation circuit that calculates a target rotation angle of a shaft; an offset angle calculation circuit that calculates an offset angle relative to the target rotation angle; a final target rotation angle calculation circuit that calculates a final target rotation angle of the shaft; and a feedback control circuit that executes feedback control that adapts a real angle to the final target rotation angle. The offset angle calculation circuit calculates an estimated rotation angle deviation based on a value of a current of a turning motor immediately before a specific event occurs, and calculates the offset angle by subtracting the real angle and the estimated rotation angle deviation from the target rotation angle.