Outboard Motor Trim Sensor Fault Detection for Actuator Restriction
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Solution Overview
Problem
Existing propulsion devices for watercraft fail to accurately detect trim angle sensor failures, particularly those caused by minor offsets due to static electricity, leading to inappropriate trim angle control.
Innovation Solution
A propulsion device equipped with an electronic control unit that monitors trim angle sensor output at predetermined intervals, detects failures by comparing current and previous values, and restricts actuator operation when deviations exceed threshold values, ensuring accurate trim angle control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If threshold-based failure detection method is used, then major failures (wire breaks, short circuits) can be detected, but small failures (static electricity offset) cannot be detected
Solution Approach 1:
The system performs preliminary monitoring of trim angle values by storing them in memory and comparing current values with stored values to detect failures before they cause harmful effects. This proactive approach enables detection of small offsets that threshold methods miss.
Solution Approach 2:
The system continuously feeds back trim angle sensor values to the control unit, which compares current values with previously stored values. This feedback mechanism enables real-time detection of both small and large failures by identifying abnormal changes in the trim angle readings.
2Reliability
If continuous monitoring at high frequency is performed, then failure detection speed is improved, but energy consumption and processing load increase
Solution Approach 1:
The control unit monitors trim angle values at predetermined time intervals rather than continuously. This periodic monitoring approach maintains reliable failure detection while reducing energy consumption and processing load compared to continuous high-frequency monitoring.
Solution Approach 2:
The system monitors only when necessary by comparing current trim angle values with previously stored values only at predetermined intervals. This partial monitoring approach provides sufficient reliability for safety-critical failure detection without the excessive energy consumption of continuous monitoring.
Data Source
AI summary
The outboard motor 3 includes an electronic control unit 33 that acquires a trim angle from a trim angle sensor and controls the actuator for trim adjustment. The electronic control unit acquires the trim angle at predetermined time intervals, stores each stably obtained trim angle in the memory as a stop trim angle, and compares each current value of the detected trim angle with the stop trim angle. It is determined if the trim angle sensor is abnormal or not based on the current value of the detected trim angle and the stop trim angle, and when it is determined that the trim angle sensor is abnormal, the operation of the actuator is restricted.