Steering Control Device Phase Compensation for Travel Mode Stability
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Solution Overview
Problem
The stability of a steering system is sensitive to travel mode, particularly when power transmission between the steering shaft and turning wheels is cut off, leading to instability, especially when abnormalities in vehicle speed are detected.
Innovation Solution
A steering control device that adjusts phase compensation based on different travel modes, including normal and abnormal conditions, using a processor to control a reaction force motor and a turning motor, with processes for reaction force setting, phase compensation, and reaction force application, allowing for adaptive phase compensation according to vehicle speed and intervention modes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If phase compensation is performed using a fixed method, then the steering system is stable under normal conditions, but the system becomes unstable when travel mode changes (especially when power transmission is cut off)
Solution Approach 1:
The phase compensation method is made dynamic by switching between different compensation values based on the detected travel mode. The control device determines the current travel mode and selects appropriate phase compensation values from multiple predetermined options, allowing the system to adapt its phase compensation strategy to match the current operating conditions rather than using a fixed compensation value
Solution Approach 2:
The system changes the phase compensation parameter based on travel mode detection. Multiple predetermined phase compensation values are stored, and the appropriate value is selected according to the detected travel mode, thereby optimizing steering stability for each specific operating condition
2Ease of operation
If the steering system operates without power transmission connection, then steering effort is reduced, but the system becomes prone to instability
Solution Approach 1:
When the travel mode indicates power transmission disconnection, the system selects a specific phase compensation value from predetermined options that is optimized for this condition. This parameter adjustment compensates for the loss of mechanical feedback and stabilizes the steering system while maintaining the ease of operation benefit
3Device complexity
If a single phase compensation value is used for all conditions, then the control system is simple, but the system cannot maintain stability across different travel modes and abnormal conditions
Solution Approach 1:
The control system dynamically selects from multiple predetermined phase compensation values based on the detected travel mode. This approach maintains relatively simple control logic while achieving adaptive stability across different operating conditions through selective parameter application
Solution Approach 2:
The phase compensation system serves multiple functions by using a single selection mechanism that handles both normal and abnormal travel modes. The same control structure universally applies appropriate compensation values across all operating conditions, maintaining stability without requiring separate control systems for each mode
Data Source
AI summary
A steering control device includes a processor that controls, as a target, a steering system including a reaction force motor that applies a steering reaction force to a steering shaft and a turning motor that turns a turning wheel, and that executes a reaction force setting process, a phase compensation process, and a reaction force application process. The reaction force setting process is a process of setting the steering reaction force using the phase compensation process. The reaction force application process is a process of operating the reaction force motor so as to produce a reaction force as set by the reaction force setting process. The phase compensation process is a process of performing phase compensation of the steering reaction force in a different manner when a travel mode of a vehicle is different.