Redundant Power Steering Motor Control Under Sensor and Circuit Failure
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Solution Overview
Problem
Existing motor driven power steering systems lack redundancy in their components, particularly in the driving motor, position sensors, and processors, which can lead to instability and failure under external magnetic fields, compromising steering safety and reliability.
Innovation Solution
A redundancy structure is implemented in the motor driven power steering system with independent control circuits for the driving motor, position sensors, and processors, allowing the system to operate even if one component fails, using a double winding motor and independent power supplies, and incorporating robust position sensors arranged in a magnetic flux direction for enhanced reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional single-winding motor with single processor control is used, then the device complexity is low, but the reliability deteriorates due to lack of redundancy against magnetic field interference and component failure
Solution Approach 1:
The system is divided into two independent control channels, each with its own processor, position sensor, and driving circuit. The double-winding motor is segmented into first and second windings that can operate independently. This segmentation allows one channel to take over if the other fails, resolving the contradiction by providing redundancy without requiring a completely separate backup system.
Solution Approach 2:
The patent implements beforehand cushioning by pre-configuring redundant components (dual processors, dual position sensors, dual driving circuits) that can compensate for potential failures before they occur. The system includes error detection mechanisms that identify failures and switch to the redundant channel proactively, cushioning against the harmful effects of magnetic field interference or component breakdown.
2Reliability
If redundant components are added to improve reliability, then the reliability improves, but the device complexity increases
Solution Approach 1:
The patent merges the redundant components into a unified dual-channel control architecture where both processors, position sensors, and driving circuits share the same motor and control framework. This merging approach allows the system to achieve redundancy while maintaining a relatively integrated structure, reducing the complexity increase compared to having completely separate backup systems.
Solution Approach 2:
Each processor, position sensor, and driving circuit is designed to be universal and interchangeable, capable of performing the same function. The first and second windings of the motor are designed with identical characteristics, allowing either winding to drive the motor independently. This universality simplifies the overall system architecture by using standardized components throughout the redundant channels.
3Measurement precision
If position sensors are arranged in magnetic flux direction, then the measurement precision improves, but the object-affected harmful factors increase due to magnetic field interference
Solution Approach 1:
The patent uses two separate position sensors (first and second position sensors) that both detect the rotational position of the motor. By having duplicate sensing channels, the system can compare readings from both sensors to identify and compensate for magnetic field interference effects, maintaining measurement precision while mitigating the harmful effects of magnetic sensitivity.
Solution Approach 2:
The dual position sensor configuration enables feedback mechanisms where each sensor's readings can be cross-validated. When magnetic field interference affects one sensor, the other sensor provides a reference reading that allows the system to detect and correct for the interference, maintaining accurate position detection despite the harmful magnetic field effects.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The redundancy structure ensures stable and reliable operation of the motor driven power steering system by enabling continued operation even if one component fails, enhancing safety and reliability, especially in autonomous driving scenarios.
Implementation Method 1
first and second position sensors that detect a rotational position of the driving motor
Data Source
AI summary
Disclosed is motor driven power steering system of a redundancy structure. The system includes a driving motor that drives a steering wheel, first and second power circuits that supply control power, first and second driving circuits that drive the driving motor, first and second position sensors that detect a rotational position of the driving motor, and first and second processors operatively coupled to the driving motor. The first processor and second processors are operatively coupled to respective redundant elements of the power circuits, the position sensors, and the driving circuits. Each of first processor and the second processor independently receives steering control signals from the upper-level control device to allow the driving circuits to be operated based on the respective position sensors, thereby allowing the driving motor to be operated.