Steering Rack Offset Detection for Belt Jump and Suspension Damage
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Solution Overview
Problem
Existing electromechanical steering systems for road vehicles do not effectively monitor the mechanical components of the steering linkage and suspension for damage, particularly distinguishing between belt jumps and suspension issues during straight driving, leading to potential undetected damage.
Innovation Solution
A method that continuously checks the vehicle's straight run state, determines the instantaneous rack position, and calculates offsets to differentiate between belt jumps and suspension damage, using sensors and algorithms to detect pull situations and adjust the steering system's operation accordingly, enabling the detection of damage and issuing warnings to the driver.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the system only monitors motor position and steering angle correlation, then belt jump detection is provided, but suspension damage and steering linkage damage cannot be detected
Solution Approach 1:
The monitoring system is extended to perform multiple detection functions: it continues to detect belt jumps through motor position and steering angle correlation, while simultaneously detecting suspension damage through pull situation analysis during straight running, and monitoring steering linkage through center position verification. This multi-functional approach allows one system to provide comprehensive safety monitoring across different failure modes.
Solution Approach 2:
The detection process is segmented into distinct operational phases: straight run state detection, belt jump detection mode, and suspension damage detection mode. By dividing the monitoring function into separate detectable conditions (center position offset, pull situation, correlation offset), the system can identify specific failure types without confusion, improving overall reliability.
2Reliability
If the system reduces servo-assistance upon detecting belt jump, then further belt damage is prevented, but no information is provided about steering linkage or suspension damage
Solution Approach 1:
The system implements continuous feedback monitoring of the vehicle's straight running state by comparing actual rack position with expected position based on steering angle. This feedback loop provides ongoing information about system health, allowing the control device to distinguish between belt jumps (temporary correlation offset) and suspension damage (persistent position offset with pull situation), thereby preventing further damage while providing diagnostic information.
3Reliability
If the system monitors rack position and pull situation continuously, then suspension damage can be detected, but system complexity increases
Solution Approach 1:
The system uses existing sensors (steering angle sensor, motor position sensor) and available data (rack position from steering control, pull situation from motor torque sensor) to perform suspension damage detection. No additional dedicated sensors are required, as the system repurposes existing measurement capabilities for the new detection function, thereby maintaining reliability while limiting complexity increase.
Data Source
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AI summary
The invention relates to a Method to control a steering apparatus comprising following steps: (A) Checking at every time whether there is a straight run state of the vehicle or not; (B) If the straight run state of vehicle is reached, determines the instantaneous rack position (R) and calculates a new offset as to a difference between the instantaneous rack position (R) and the first position (R0) of said rack (7); (C) Checking in a first justify operation, whether the new offset of the rack position in the straight run state of vehicle to the first rack position differs to an old offset, which where determined as the new offset at an earlier time, and set in this case the first justify result as to true and otherwise as to false; (D) Checking in a second justify operation, whether the pull situation value exceeds a threshold value and set in this case the second justify result as to true and otherwise as to false; (E) If the first and second justify results are true, set a suspension device status as to a "suspension damaged" status; (F) If the first justify result is true and the second justify result is false, set a belt jump status as to a "belt jumped" status.