Shift Range Actuator Control with ECU Failover Switching
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Solution Overview
Problem
Conventional shift range control devices are vulnerable to failures if the single ECU controlling the motor for switching the vehicle's shift range experiences an abnormality, leading to potential disruptions in shift range switching and reduced efficiency due to deviations in command output timings from multiple control units.
Innovation Solution
A shift range control device with multiple control units and monitoring units, where each control unit independently monitors its own and other units' states, allowing seamless switching to a backup unit in case of an abnormality, ensuring continuous operation and maintaining efficiency by using only one control unit at a time.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a single ECU is used to control the motor for switching shift range, then the device complexity is reduced, but the reliability deteriorates because the system becomes vulnerable to failures when the ECU experiences an abnormality
Solution Approach 1:
The control system is segmented into multiple independent control units (first control unit and second control unit), each capable of independently controlling the motor. This segmentation allows the system to divide the control function across multiple units, so that if one unit fails, the other can take over, thereby improving reliability without requiring a completely complex redundant system.
Solution Approach 2:
The system changes the operational parameter of the control units by switching which unit is active. The control units can be switched based on their operational status, allowing the system to adapt to failures by changing the active control unit parameter. This enables reliable operation while maintaining a manageable device complexity through parameter-based switching rather than structural redundancy.
2Reliability
If multiple control units are used to control the motor, then the reliability is improved through backup capability, but the device complexity increases
Solution Approach 1:
The first control unit and second control unit are merged into a single integrated control system where both units share the same physical space and control architecture. They are combined in such a way that they can cooperatively manage the motor control, with one unit serving as backup for the other. This merging approach improves reliability through redundancy while minimizing the increase in device complexity by consolidating the control units within a unified system framework.
3Reliability
If multiple control units output commands simultaneously, then the reliability is improved through redundancy, but the actuator efficiency deteriorates due to deviation in command output timings
Solution Approach 1:
The control system dynamically adjusts which control unit is active based on real-time operational status. Instead of having multiple control units operate simultaneously with fixed roles, the system dynamically switches between the first and second control units depending on which one is functioning properly. This dynamic approach maintains control redundancy for reliability while ensuring that only one control unit outputs commands at a time, thereby preventing timing deviations and maintaining actuator efficiency.
Solution Approach 2:
The system ensures continuous useful action by maintaining the capability to control the motor without interruption. The first and second control units are designed so that if one fails, the other can immediately take over, ensuring continuous operation. This continuity is achieved by having standby capability rather than simultaneous operation, which prevents timing conflicts while maintaining the reliability benefit of redundancy.
Data Source
AI summary
A shift range control device switches a shift range by controlling driving of an actuator. A plurality of control units are configured to control the driving of the actuator. A plurality of monitoring control units are correspondingly provided for the plurality of control units, and configured to monitor the corresponding control units. The driving of the actuator is controlled by one of the control units, which is in a normal state. When an abnormality occurs in the one of the control units being used to control the driving of the actuator, the one is switched to another one of the control units to control the driving of the actuator.