Electric Motor Servo Loop Control for Aircraft Wheel Torque

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Solution Overview

Problem

Current methods for controlling an aircraft's ground speed and orientation are not precise and require pilots to adapt to environmental conditions and structural characteristics, leading to inefficient and labor-intensive operations.

Innovation Solution

A method using electric motors for aircraft wheel rotation, implementing servo loops for speed and acceleration regulation to generate torque commands, allowing for precise ground speed control and assistance in orientation control, independent of external environmental and structural factors.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If manual control methods are used for ground speed and orientation, then the pilot has direct control over the aircraft, but the control precision is poor and requires constant adaptation to environmental conditions

Engineering Contradiction:
Improveground speed control precisionVSAvoidpilot workload
Core Design Contradiction:
Measurement precisionVSEase of operation

Solution Approach 1:

The control system performs self-regulation through automated servo loops that continuously adjust torque commands based on feedback from speed and acceleration sensors, eliminating the need for constant manual intervention while maintaining precise ground speed control

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The system implements closed-loop feedback control where sensors monitor actual wheel speed and acceleration, compare these values against desired setpoints, and automatically adjust motor torque commands to eliminate errors, thereby improving precision without increasing pilot workload

Inventive Principle:
Principle #23Feedback

2Measurement precision

If electric motors with servo loops are implemented for wheel rotation, then precise ground speed control is achieved, but the device complexity increases

Engineering Contradiction:
Improveground speed control precisionVSAvoidcontrol system complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The electric motor system serves multiple functions simultaneously: it provides propulsion torque to move the aircraft, acts as a sensor through back-EMF for speed measurement, and functions as an actuator for orientation control, thereby achieving precise control without proportionally increasing system complexity

Inventive Principle:
Principle #6Universality (Multi-functionality)

Solution Approach 2:

The system combines the motor, sensor, and controller into an integrated electromechanical system where the motor's electrical characteristics are used for both propulsion and measurement, reducing the need for separate components and simplifying the overall control architecture

Inventive Principle:
Principle #5Merging (Combining)

Data Source

PatentEP2886454B1A method of controlling an electric motor for driving rotation of an aircraft wheel
Publication Date: 2018.04.04 SAFRAN LANDING SYSTEMS
  • EP2886454B1 patent drawingFigure 1a
  • EP2886454B1 patent drawingFigure 1b
  • EP2886454B1 patent drawingFigure 2~3

AI summary

A method for controlling an electric motor for rotating an aircraft wheel (4a, 4b) intended to generate a torque command to control the motor, the method being characterized in that it comprises the implementation of: - a first servo loop (23) having as its input a speed setpoint, as its feedback a signal representing the speed of the wheel or the aircraft, and as its output an acceleration setpoint (Cons_a); - a second servo loop (24) having as its input the acceleration setpoint (Cons_a), as its feedback a signal representing the acceleration of the wheel (Ar) or the aircraft, and as its output the torque command