Actuator Backlash Measurement Using Built-In Position Sensing
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Solution Overview
Problem
Current methods for detecting backlash in actuators are limited by the need to remove the actuator from its operational environment for inspection, requiring special tooling and fixtures, and can only be done during maintenance or repair.
Innovation Solution
A system and method for in-situ backlash measurement in actuator assemblies, which includes a housing assembly, an actuator, a drive source, position sensors, and a controller. The controller implements a built-in test by commanding the actuator to move between fully-retracted and fully-extended positions, reading positions, and calculating backlash based on travel distances.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If current backlash detection methods are used, then backlash can be detected, but the actuator must be removed from the aircraft and special tooling is required
Solution Approach 1:
The actuator performs its own backlash measurement using integrated sensors and a built-in test routine. The actuator controller commands the motor to move the actuator through its range of motion and compares the actual position feedback with the commanded position to calculate backlash, eliminating the need for external measurement equipment and manual inspection procedures
Solution Approach 2:
The position sensors originally intended for normal actuator operation are dual-used for backlash measurement. The same motor, sensors, and controller used for actuator control are also employed for backlash detection, eliminating the need for specialized tooling and fixtures
2Measurement precision
If current backlash inspection methods are used, then backlash can be measured, but inspection can only be done during maintenance or heavy checks
Solution Approach 1:
The backlash measurement system operates continuously during normal actuator operation. The actuator controller continuously monitors the relationship between commanded position and actual position feedback, enabling backlash detection at any time without interrupting actuator function or requiring scheduled maintenance shutdowns
Solution Approach 2:
The system performs backlash measurement as part of the normal actuator operation cycle. By continuously comparing commanded and actual positions during routine actuator movement, the system detects backlash before it leads to failure, enabling preventive maintenance rather than reactive repair
3Measurement precision
If the actuator is removed for inspection, then backlash can be inspected, but operational monitoring is prevented
Solution Approach 1:
The actuator autonomously performs backlash self-diagnosis using its own control system and position feedback. The actuator controller executes a built-in test routine that commands motor movement and calculates backlash from position discrepancies, allowing the actuator to monitor its own health while installed in the aircraft
Solution Approach 2:
The patent replaces mechanical measurement systems (external fixtures, manual measurement tools) with an electronic/software-based solution. The backlash measurement is derived from electrical position feedback signals and control commands, eliminating the need for mechanical contact with the actuator during measurement
Data Source
AI summary
A system and method for measuring an amount of backlash in an actuator assembly that includes a housing assembly, an actuator, a drive source, an actuator position sensor, a drive source position sensor, and a controller. The controller is in operable communication with the drive source, the actuator position sensor, and the drive source position sensor, and is configured to selectively implement a built-in test that determines the amount of backlash in the actuator assembly.