Redundant Electric Steering Control for Offset-Free Motor Synchronization
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Solution Overview
Problem
In electronic steering control systems for autonomous vehicles, offsets between dual controllers of the MDPS system degrade control performance, leading to vibration and improper path tracking, hindering stable autonomous driving.
Innovation Solution
An electronic steering control apparatus with a redundancy system that includes two position controllers, which calculate average steering angles and feedback angles for synchronized motor control, and employs communication checks and error value resets to stabilize control when communication is lost, gradually increasing control gains to prevent oscillation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a redundancy system with two position controllers is introduced to ensure continuous steering control, then reliability is improved, but offsets accumulate between controllers causing control performance degradation
Solution Approach 1:
The system performs preliminary offset removal calibration before normal operation to prevent offset accumulation. The calibration process establishes a baseline relationship between the two controllers, enabling them to work synchronously from the start and preventing performance degradation before it occurs.
Solution Approach 2:
The system continuously monitors the steering angles from both controllers and uses feedback to detect and correct offset differences. By comparing the steering angles in real-time and applying corrective adjustments, the system maintains synchronized operation between the two controllers while preserving redundancy.
2Reliability
If dual controllers operate independently to maintain redundancy, then reliability is improved, but vibration occurs due to accumulated offsets
Solution Approach 1:
The system uses feedback control to continuously monitor and correct offset differences between the two controllers. By detecting angular deviations and applying real-time corrections, the system eliminates the vibration-causing offsets while maintaining the independent operation and redundancy of both controllers.
Solution Approach 2:
The system dynamically adjusts control parameters including offset values and control gains based on real-time operational conditions. By changing these parameters adaptively, the system suppresses vibration while preserving the redundancy benefit of dual independent controllers.
3Manufacturing precision
If offset calibration is performed continuously to maintain control accuracy, then manufacturing precision is improved, but device complexity increases
Solution Approach 1:
The system performs comprehensive offset calibration preliminarily before normal operation, establishing accurate baseline parameters in advance. This preliminary action eliminates the need for continuous complex calibration routines during operation, reducing system complexity while maintaining high control accuracy throughout the vehicle's operation.
Solution Approach 2:
The system uses its own operational data and feedback from normal operation to perform self-calibration and offset correction without requiring external intervention or complex additional calibration equipment. This self-service approach maintains accuracy while minimizing added system complexity.
Data Source
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AI summary
Provided is an electronic steering control apparatus to which a redundancy system is applied and which includes a first position controller and a second position controller. When communication is established between the first and second position controllers, the first position controller may control the position of a first motor on the basis of command steering angles θ1 and θ2 from a control unit and feedback steering angles θm1 and θm2 from a motor, and the second position controller may control the position of a second motor on the basis of the command steering angles θ1 and θ2 from the control unit and the feedback steering angles θm1 and θm2 from the motor.