Redundant Steering Assist Control for Sensor Failure Handover
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Solution Overview
Problem
In electronic power steering systems with redundancy, there is a delay in control calculation that causes discomfort to drivers due to the failure of a sensor, leading to incomplete or inaccurate steering motor control.
Innovation Solution
A steering power assistance system with dual die integrated circuits and controllers that perform internal communication to select a normal state detection signal and share target values for precise control, ensuring continuous and stable operation even if one sensor fails.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a redundancy system with multiple sensors and controllers is implemented, then system reliability is improved, but control calculation delay occurs when sensor failure is detected
Solution Approach 1:
The system performs preliminary cross-validation by having each controller receive and validate detection signals from both sensors before normal operation. When a sensor fails, the other controller already has the valid detection signal ready, eliminating the need for recalculation and avoiding control delay.
Solution Approach 2:
The patent introduces an intermediary validation mechanism where controllers exchange and cross-check detection signals. This intermediary validation layer allows the system to identify sensor failures without interrupting the control signal flow to the steering motor.
2Reliability
If control transfer between controllers is performed upon sensor failure, then system continuity is maintained, but driver discomfort increases due to control interruption
Solution Approach 1:
The system maintains continuous control action by having the second controller immediately generate control signals using its pre-acquired valid detection signal when the first controller detects sensor failure. This eliminates control interruption and maintains steering assistance continuity, preserving driver comfort.
Solution Approach 2:
Instead of the failed controller attempting to recover or transfer control after failure detection, the patent inverts the approach by having the second controller (with lower priority) already prepared with valid detection signals to immediately take over control generation without interruption.
3Measurement precision
If detection signals from multiple sensors are used, then measurement accuracy is improved, but control precision decreases when sensor failure occurs
Solution Approach 1:
The system implements feedback through cross-validation where each controller receives detection signals from both sensors and validates them against each other. This feedback mechanism allows the system to identify and exclude failed sensor signals, maintaining control precision by using only valid detection signals.
Solution Approach 2:
The patent changes the parameter state of detection signals by having controllers evaluate the validity status of each signal and selectively use only normal-state detection signals for control calculations, ensuring control precision even when some sensors fail.
Data Source
AI summary
The present disclosure relates to a steering power assistance system and an electronic control device included therein. Specifically, a steering power assistance system according to the present disclosure comprises: two sensors including a dual die integrated circuit; two controllers connected to the two sensors, respectively, and capable of performing internal communication; and a steering motor, wherein among the two controllers, one controller in the following turn in the sequence of controlling generates a control signal and outputs the control signal to the steering motor, according to a target value calculated by another controller which is in a normal state and in the preceding turn in the sequence of controlling.