Electromechanical Actuator Torque Control via Electronic Jam Detection

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Solution Overview

Problem

Mechanical solutions for de-coupling motors from electromechanical actuators in aircraft applications are heavy and performance varies with environmental factors, necessitating a solution that reduces weight and improves consistency across different conditions.

Innovation Solution

An electronic control system using sensors to monitor and adjust motor torque, incorporating motor control laws that detect impending jams and reduce torque output to prevent damage, replacing mechanical components with electronic controls.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If mechanical solutions (torque brake or slip clutch) are used to de-couple the motor from the actuator, then the actuator can be protected from motor excess torque, but the system becomes heavier and performance varies with environmental factors

Engineering Contradiction:
Improveactuator protection from excess torqueVSAvoidsystem weight
Core Design Contradiction:
ReliabilityVSWeight of moving object

Solution Approach 1:

The patent replaces mechanical de-coupling solutions (torque brake, slip clutch) with an electronic control system that monitors actuator position and motor torque, and electronically controls motor power output to prevent excess torque conditions. This substitution eliminates heavy mechanical components while maintaining protection functionality through software-based torque management and electronic motor control.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent extracts the de-coupling function from mechanical components and implements it through electronic control logic. The controller separates the motor control function from mechanical de-coupling by using sensors and electronic actuators to manage torque delivery, removing the need for physical torque-limiting mechanisms.

Inventive Principle:
Principle #2Taking out (Extraction)

2Reliability

If mechanical solutions (torque brake or slip clutch) are used to de-couple the motor from the actuator, then the actuator can be protected from motor excess torque, but performance consistency deteriorates across environmental factors

Engineering Contradiction:
Improveactuator protection from excess torqueVSAvoidperformance consistency across environmental factors
Core Design Contradiction:
ReliabilityVSAdaptability or versatility

Solution Approach 1:

The patent replaces temperature-sensitive mechanical components with an electronic control system that uses sensors and algorithms to adapt to environmental conditions. The electronic system maintains consistent performance across temperature ranges by dynamically adjusting control parameters rather than relying on mechanical properties that vary with temperature.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent changes control parameters (torque limits, power output, duty cycle) based on environmental conditions and operational state. The controller dynamically adjusts these parameters to maintain optimal performance and protection across varying temperatures and conditions, rather than relying on fixed mechanical characteristics.

Inventive Principle:
Principle #35Parameter changes

3Ease of operation

If the motor continues to provide power during a jam condition, then the actuator may be driven beyond its range of motion, but this causes damage to the motor and actuator

Engineering Contradiction:
Improveactuator range of motionVSAvoidmotor and actuator integrity
Core Design Contradiction:
Ease of operationVSStrength

Solution Approach 1:

The patent implements preliminary protective action by continuously monitoring actuator position and motor torque before damage occurs. The control system detects jam conditions through sensor feedback (position deviation, current spikes) and preemptively reduces or cuts motor power to prevent damage, rather than waiting for mechanical failure.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent uses feedback from position sensors and motor current sensors to detect jam conditions and adjust motor power accordingly. The control system continuously monitors operational parameters and provides real-time feedback control to prevent excess torque and protect the actuator-motor system from damage.

Inventive Principle:
Principle #23Feedback

Data Source

PatentEP3005549B1Active impact force/torque control for an electromechanical actuator
Publication Date: 2019.04.24 EATON CORP
  • EP3005549B1 patent drawingFigure 1~2

AI summary

A system that improves on known systems for reducing output torque by a motor in the event of a jam may include an electromechanical actuator (EMA), a motor configured to drive the EMA and a controller. The controller may be coupled to the motor and configured to receive a speed of the EMA and a position of the EMA. The controller may be further configured to determine whether a jam of the EMA is imminent or is occurring according to the EMA speed, EMA position, and a known range of motion of the EMA, and to provide an input signal to the motor to reduce a torque of the motor if a jam of the EMA is imminent or is occurring.