Steering Control Device Catch-Up Prevention
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Solution Overview
Problem
Existing vehicle steering systems, particularly steer-by-wire systems, struggle to recognize and prevent catch-up due to limitations in motor capacity, leading to inadequate steering feedback and desired speed control.
Innovation Solution
A steering control device and method that calculates allowed rack speed information based on rack force and motor performance, and uses this information to determine catch-up prevention torque, thereby preventing catch-up by controlling the first motor accordingly.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the motor capacity is increased to prevent catch-up, then the steering feedback performance is improved, but the device complexity and cost increase
Solution Approach 1:
The system calculates allowed rack speed information based on motor performance information before actual steering operations occur. By predicting the motor's capacity limits in advance and comparing command rack speed with allowed rack speed, the system prevents catch-up situations before they happen, rather than requiring oversized motors to handle peak demands.
Solution Approach 2:
The system continuously monitors command rack speed information and allowed rack speed information, and adjusts the steering feedback torque accordingly. When catch-up is detected or predicted, the system modifies the feedback torque to prevent the issue, creating a closed-loop control system that adapts to motor capacity constraints.
2Device complexity
If the motor capacity is limited, then the device complexity is reduced, but catch-up occurs resulting in inadequate steering feedback
Solution Approach 1:
The system dynamically adjusts the steering feedback torque parameter based on the relationship between command rack speed and allowed rack speed. By changing the torque parameter in response to detected conditions, the system maintains reliable steering feedback despite limited motor capacity, resolving the contradiction between limited capacity and feedback reliability.
3Speed
If the rack speed is increased to match steering wheel rotation, then the steering responsiveness is improved, but catch-up occurs due to motor capacity limitations
Solution Approach 1:
The system calculates allowed rack speed information based on motor performance before commanding the motor to move the rack. By establishing speed limits in advance based on motor capabilities, the system ensures that rack speed commands remain within reliable execution boundaries, preventing catch-up while maintaining optimal responsiveness.
Data Source
AI summary
The embodiment relates to a steering control device and method and includes a steering control device for controlling a first motor generating steering feedback torque in response to rotation of a steering wheel and a second motor generating rack driving torque for moving a rack, comprising a calculation unit calculating allowed rack speed information regarding a rack speed allowed when driving the rack using the second motor, based on rack force information and preset second motor performance information and calculating catch-up prevention torque information for preventing catch-up in the steering wheel, based on the allowed rack speed information and command rack speed information generated to drive the rack at a speed in response to rotation of the steering wheel and a controller performing catch-up prevention control on the first motor based on the catch-up prevention torque information.