Electromechanical Actuator Torque Estimation via Kalman Filter

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Solution Overview

Problem

Existing methods for monitoring electromechanical actuator systems in aircraft, such as those used for movable elements like ailerons, fail to accurately measure electromagnetic torque, leading to incomplete parameter monitoring and increased costs, weight, and complexity due to the need for external equipment or additional sensors.

Innovation Solution

A method using a Kalman filter to estimate voltage drops and electromagnetic torque in electromechanical actuator systems, leveraging operational data like motor current, control voltage, and rotation speed, thereby eliminating the need for additional sensors and allowing real-time calculation of electromagnetic torque during flight operations.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If additional sensors are integrated to measure electromagnetic torque, then measurement precision is improved, but device complexity and cost increase

Engineering Contradiction:

Improveelectromagnetic torque measurementVSAvoidsensor integration

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The patent replaces physical sensors with a mathematical model that calculates electromagnetic torque using existing electrical measurements (current, voltage, frequency) and motor parameters. The torque is derived from the imaginary component of the product of stator current and back-EMF in the synchronous reference frame, eliminating the need for additional mechanical or electromagnetic torque sensors.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent introduces an intermediary computational process that uses readily available electrical measurements as mediators to infer electromagnetic torque. Instead of directly measuring torque, the system uses current sensors and voltage measurements as intermediaries, processing them through coordinate transformations and mathematical calculations to obtain torque information.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Measurement precision

If external measuring equipment is used to measure electromagnetic torque, then measurement precision is improved, but loss of time and productivity increase

Engineering Contradiction:

Improveelectromagnetic torque measurementVSAvoidaircraft ground time

Core Design Contradiction:

Measurement precisionVSLoss of time

Solution Approach 1:

The patent enables the aircraft's own flight data systems to perform torque measurements during normal operation. The existing sensors, processors, and control systems serve dual purposes: controlling the motor and simultaneously measuring electromagnetic torque, eliminating the need for separate external measurement equipment and ground-based testing.

Inventive Principle:

Principle #25Self-service

Solution Approach 2:

The patent enables continuous torque measurement throughout flight operations using existing sensors and computational methods. The system continuously processes current, voltage, and frequency data to provide real-time torque information, rather than requiring intermittent external measurements during ground-based maintenance windows.

Inventive Principle:

Principle #20Continuity of useful action

3Device complexity

If traditional sensors are used around motor and actuator, then device complexity is minimized, but measurement precision deteriorates

Engineering Contradiction:

Improvesensor arrangementVSAvoidelectromagnetic torque measurement

Core Design Contradiction:

Device complexityVSMeasurement precision

Solution Approach 1:

The patent makes existing electrical sensors serve multiple functions: they continue to provide control signals for motor operation while simultaneously providing data for electromagnetic torque calculation. The current and voltage sensors used for motor control also serve as measurement inputs for torque estimation, eliminating the need for separate dedicated torque measurement hardware.

Inventive Principle:

Principle #6Universality (Multi-functionality)

Data Source

PatentUS10451502B2Method for monitoring an electromechanical actuator system

Publication Date: 2019.10.22 SAFRAN ELECTRONICS & DEFENSE (FR)

AI summary

The invention relates to a method of monitoring an electromechanical actuator system, the method comprising the steps of estimating the voltage drop in the power supply to the motor associated with defects of the inverter by means of a Kalman filter, estimating (300) at least the electromagnetic torque coefficient of the motor by taking account of the estimated voltage drop, and calculating (400) the electromagnetic torque of the motor from the electromagnetic torque coefficient of the motor.