Steering Device Actuator Error Detection via Torque Monitoring
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Solution Overview
Problem
Steer By Wire (SBW) steering devices lack mechanical connection, leading to reduced steering feel and potential issues like rust in road wheel actuators and belt skipping, which can prevent vehicle steering, causing human and material damage.
Innovation Solution
A steering device with an electronic control unit that measures motor torque and rotation data to detect errors in the road wheel actuator, displaying errors such as rust or belt skipping on a display unit, allowing for early detection and prevention of steering failure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If SBW-type steering device is used to eliminate mechanical connection, then steering convenience is improved, but steering feel is reduced
Solution Approach 1:
The patent replaces the mechanical connection system with an electronic control system. The electronic control unit receives steering angle information from a steering angle sensor and road wheel angle information from a road wheel angle sensor, then controls the road wheel actuator to adjust the road wheel angle accordingly, eliminating the need for mechanical connection while maintaining steering functionality.
Solution Approach 2:
The patent introduces a friction element as an intermediary component between the road wheel actuator and the steering system. This friction element provides frictional force to simulate the steering feel that would normally be transmitted through mechanical connection, allowing the driver to perceive road conditions while maintaining the benefits of electronic control.
2Adaptability or versatility
If SBW steering device operates without mechanical connection, then steering flexibility is improved, but risk of rust and belt skipping increases
Solution Approach 1:
The patent implements a diagnostic function that operates before actual steering failure occurs. The electronic control unit continuously monitors the road wheel actuator's operational status by comparing commanded positions with actual positions, and detects abnormalities such as rust or belt skipping early, allowing for preventive maintenance before complete failure occurs.
Solution Approach 2:
The patent employs a feedback mechanism where the electronic control unit receives actual road wheel angle information from a sensor and compares it with the commanded angle. When a discrepancy exceeds a predetermined threshold, the system identifies this as an error condition indicating potential issues like rust or belt skipping, and can alert the driver or initiate corrective actions.
3Measurement precision
If road wheel actuator is monitored continuously, then error detection capability is improved, but system complexity increases
Solution Approach 1:
The patent makes the electronic control unit multi-functional by integrating both the steering control function and the actuator diagnostic function into a single controller. The same sensor inputs (steering angle sensor, road wheel angle sensor) used for normal steering control are also utilized for monitoring actuator health, eliminating the need for separate diagnostic hardware and reducing overall system complexity.
Solution Approach 2:
The system performs self-diagnosis using its own existing sensors and control architecture. The electronic control unit uses the steering angle information and road wheel angle information that it already collects for normal operation to detect actuator errors, allowing the system to monitor its own health without requiring additional external monitoring equipment.
Data Source
AI summary
A steering device for detecting an error of a road wheel actuator according to an exemplary embodiment of the present disclosure includes an electronic control unit and a road wheel actuator. The electronic control unit may be electrically connected with a steering wheel of a vehicle, and the road wheel actuator may be electrically connected with the electronic control unit. When the vehicle starts, the electronic control unit may rotate the steering wheel in one direction or an opposite direction to the one direction by driving the road wheel actuator and measure data of the road wheel actuator. A method of determining an error of a road wheel actuator according to another exemplary embodiment of the present disclosure includes a first operation, a second operation, and a third operation.