Steering Control Circuit With Partial Release for Small-Slewing
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Solution Overview
Problem
Existing electric power steering systems face a decrease in small-slewing performance due to end-abutting relaxation control, which restricts the movement of the rack shaft at a virtual rack end position, leading to a larger minimum slewing radius and reduced maneuverability.
Innovation Solution
A steering control device that includes a control circuit to detect an absolute steer angle and execute end-abutting relaxation control with a partial release mechanism, adjusting the current command value to allow movement to the actual rack end position when a slewing intention is detected, thereby enhancing small-slewing performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If end-abutting relaxation control is executed to relax impact of rack end abutting, then impact of end abutting is reduced, but movement of rack shaft is restricted at virtual rack end position causing larger minimum slewing radius
Solution Approach 1:
The control circuit dynamically adjusts the current command value based on the steering angle and detected slewing intention. When slewing intention is detected, the control circuit increases the current command value to allow the rack shaft to reach the actual end position, thereby maintaining small-slewing performance while still providing end-abutting relaxation control during normal operation.
Solution Approach 2:
The control circuit changes the parameter of current command value based on operating conditions. By detecting the steering angle and determining slewing intention, the system adjusts the current command value from a limited value (during end-abutting relaxation) to an increased value (when slewing is needed), thus resolving the contradiction between impact relaxation and slewing performance.
2Object-affected harmful factors
If current command value is limited to prevent end abutting impact, then end abutting impact is reduced, but minimum slewing radius increases
Solution Approach 1:
The control circuit dynamically adjusts the current command value based on the steering angle and detected slewing intention. When slewing intention is detected, the control circuit increases the current command value to allow the rack shaft to reach the actual end position, thereby maintaining small-slewing performance while still providing end-abutting relaxation control during normal operation.
Solution Approach 2:
The control circuit changes the parameter of current command value based on operating conditions. By detecting the steering angle and determining slewing intention, the system adjusts the current command value from a limited value (during end-abutting relaxation) to an increased value (when slewing is needed), thus resolving the contradiction between impact relaxation and slewing performance.
Data Source
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AI summary
A steering control device includes a control circuit (41) that controls a steering device. The control circuit (41) is configured to execute an end-abutting relaxation control to correct a current command value such that decrease in an end interval angle is restricted, when the end interval angle is equal to or smaller than a predetermined angle, the end interval angle indicating the distance of an absolute steer angle from an end position correspondence angle. The control circuit (41) is configured to perform a slewing intention determination of whether it is intended to perform the slewing travel of a vehicle during the execution of the end-abutting relaxation control. The control circuit (41) is configured to perform a partial release control to reduce a correction amount of the current command value in the execution of the end-abutting relaxation control when it is determined that it is intended to perform the slewing travel of the vehicle.