Electrical Flight Control Servo With Cascaded Feedback Sensor Detection
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Solution Overview
Problem
Existing electrical servo systems for flight control surfaces suffer from inaccuracies due to non-linear effects and deformations in the drive train, leading to deviations between target and actual positions, and lack effective methods to detect sensor failures.
Innovation Solution
A cascaded closed-loop control system using two sensors - a movement-related flight control surface sensor and a movement-related actuator sensor - to enhance control accuracy and detect sensor failures by comparing their outputs, with redundancy provided by multiple sensors for fault tolerance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single sensor is used for position control of the flight control surface, then the device complexity is reduced, but the control accuracy deteriorates due to non-linear effects and deformations in the drive train
Solution Approach 1:
The system divides the position measurement function into two separate sensors: one sensor measures the actuator position while another sensor measures the flight control surface position. This segmentation allows each sensor to independently compensate for drive train deformations and non-linear effects, thereby improving overall control accuracy without requiring a single complex high-precision sensor
Solution Approach 2:
The system implements feedback by using two sensors to provide position information to the controller. The controller receives feedback from both the actuator position sensor and the flight control surface position sensor, enabling it to calculate compensation values for drive train deformations and adjust the control signal accordingly, thus improving measurement precision
2Device complexity
If no redundancy is provided in the sensor system, then the device complexity is reduced, but the reliability deteriorates due to undetected sensor failures
Solution Approach 1:
The system performs preliminary action by continuously monitoring the correlation between the two sensor signals and comparing it against expected values. This preliminary check enables the detection of sensor failures before they lead to incorrect flight control, allowing the system to alert the pilot or automatically switch to a safe operating mode
Solution Approach 2:
The system uses feedback by continuously comparing the position measurements from both sensors and monitoring their correlation. When the correlation deviates from expected values, the controller detects the sensor failure and can take appropriate actions, thereby improving system reliability through continuous self-diagnosis
Data Source
AI summary
Electrical servo system for a flight control surface comprising: a flight control surface moveable with respect to a mounting portion; an electric actuator configured to actuate the flight control surface; at least one movement-related flight control surface sensor, which is configured to acquire a quantity related to a movement of the flight control surface; at least one movement-related actuator sensor, which is configured to acquire a quantity related to a movement of the actuator. In order to enhance control accuracy, a controller is provided, which is configured to control according to a cascaded closed loop control, wherein the at least one movement-related flight control surface sensor is used in an outer closed loop control for movement control of the flight control surface, and the at least one movement-related actuator sensor is used in an inner closed loop control for movement control of the actuator.