Steering Control Device Asymmetric Microcomputer Design
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Solution Overview
Problem
Existing steering control systems face the challenge of simultaneous abnormalities in constituent elements due to identical configurations and loads, leading to potential failures in both control systems if they share the same factors.
Innovation Solution
The implementation of a control device for a steering mechanism with a motor having multiple coils, where each control system uses microcomputers with different characteristics, manufactured from distinct raw materials and in different factories, to prevent simultaneous abnormalities by ensuring distinct characteristics and manufacturing processes for each system.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the same configuration is used for constituent elements of control systems, then manufacturing ease and consistency are improved, but the risk of simultaneous abnormalities increases
Solution Approach 1:
The patent applies asymmetry by intentionally creating differences between otherwise identical control systems. Specifically, it varies operational parameters such as PWM duty cycles, switching frequencies, or timing sequences between the first and second control systems. This asymmetric operation prevents synchronized failures while maintaining manufacturing consistency, as the hardware remains the same but the operational characteristics differ.
2Reliability
If different characteristics are used for microcomputers in control systems, then reliability against simultaneous abnormalities is improved, but device complexity increases
Solution Approach 1:
The patent applies local quality by introducing differences only in specific characteristics of the microcomputers rather than making the entire systems different. For example, it may vary only the clock frequency, instruction set optimization, or specific peripheral configurations of otherwise identical microcomputers. This localized differentiation suppresses simultaneous abnormalities while minimizing overall system complexity.
Data Source
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AI summary
In a control device (30) for a steering mechanism (2), the steering mechanism (2) includes a motor (20) that includes a plurality of coils (24). The plurality of coils (24) include a first coil (24a) and a second coil (24b). The control device (30) includes a first control system and a second control system configured to compute a command value for torque of the motor (20) to be applied to the steering mechanism (2). The first control system and the second control system are each configured to control power supply to the plurality of coils (24) of the motor (20) based on the command value. The first control system includes a first microcomputer (32a) that has first characteristics, and the second control system includes a second microcomputer (32b) that has second characteristics that are different from the first characteristics.