Pilot-by-Wire Actuator Angular Sensor Diagnostics
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Solution Overview
Problem
Existing pilot-by-wire system actuators lack comprehensive diagnostics for the positioning of angular sensors, which limits their ability to detect malfunctions and provide accurate feedback to the user.
Innovation Solution
An actuator with a rotary electric motor, two absolute angular sensors connected through a non-unitary gear ratio transmission, and an electronic control unit that generates a signal when deviations exceed a threshold, allowing for more thorough diagnostics and fault detection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If redundant angular sensors are added to improve diagnostics, then measurement precision and reliability are improved, but device complexity increases
Solution Approach 1:
The system implements feedback by continuously monitoring the relationship between the first angular sensor (on motor shaft) and second angular sensor (on output shaft) through the transmission gear ratio. The control unit compares actual sensor readings against expected values based on the known non-unitary gear ratio, enabling detection of sensor malfunctions or transmission issues.
Solution Approach 2:
The transmission with non-unitary gear ratio serves as an intermediary element that mechanically couples the two angular sensors. This intermediary provides a known geometric relationship between the sensors, allowing the system to detect faults by monitoring deviations from the expected gear ratio relationship rather than requiring direct comparison of identical sensors.
2Reliability
If a transmission with non-unitary gear ratio is used to couple sensors, then diagnostic capability is improved, but device complexity and manufacturing difficulty increase
Solution Approach 1:
The transmission with non-unitary gear ratio performs multiple functions: it transmits mechanical power from the electric motor to the output shaft, and simultaneously serves as a diagnostic reference by providing a known geometric relationship between the two angular sensors. This multi-functionality eliminates the need for separate diagnostic mechanisms.
Solution Approach 2:
The system performs self-diagnosis by using its own transmission gear ratio as a reference standard. The control unit continuously monitors whether the relationship between the two angular sensors matches the expected non-unitary gear ratio, enabling the system to self-detect transmission faults, sensor malfunctions, or mechanical issues without external diagnostic equipment.
3Measurement precision
If absolute angular sensors are used instead of incremental sensors, then measurement precision and reliability are improved, but device complexity and cost increase
Solution Approach 1:
The absolute angular sensors provide preliminary action by continuously maintaining accurate angular position information without requiring reset or reference updates. This eliminates the need for homing procedures and ensures that diagnostic comparisons between sensors can be performed immediately and reliably at any point in the system operation.
Data Source
AI summary
A user interface actuator for a pilot-by-wire system comprises a rotary electric motor having an output shaft suitable to be connected to a rotating user interface, a first absolute angular sensor for detecting in direct drive the number of revolutions of the shaft and a second absolute angular sensor redundant with respect to the first absolute angular sensor.