Electric Brake Actuator Drag Offset Adjustment

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Solution Overview

Problem

Aircraft brake dragging during takeoff can lead to excessive heat buildup, increasing the risk of wheel failure and damage when the landing gear is retracted, due to factors like over-pressurization, improper adjustment, or mechanical issues, which existing technologies have not adequately addressed.

Innovation Solution

A method to automatically adjust the electric actuators of the brake system by monitoring wheel spindown data and calculating a drag offset to prevent dragging, involving a system that recalculates the zero torque position of the actuators based on force measurements and communicates adjustments to the brake actuator controller.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the brake is adjusted to maintain constant torque, then the brake provides stable stopping force, but the actuator may drag the brake causing excessive heat buildup

Engineering Contradiction:
Improvebrake performance stabilityVSAvoidheat buildup from brake dragging
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The system dynamically adjusts the actuator position by calculating a drag offset based on wheel spindown characteristics. Instead of maintaining a fixed zero torque position, the system adapts the actuator position in real-time to compensate for brake dragging, thereby preventing heat buildup while maintaining reliable brake performance.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The system uses wheel spindown data as feedback to detect brake dragging conditions. By monitoring how the wheel decelerates after engine power removal, the system calculates a drag offset and adjusts the actuator position accordingly, creating a closed-loop control system that prevents excessive heat buildup.

Inventive Principle:
Principle #23Feedback

2Manufacturing precision

If the electric actuator position is manually adjusted, then the brake can be calibrated, but manual adjustment is time-consuming and imprecise

Engineering Contradiction:
Improveactuator positioning accuracyVSAvoidtime for brake calibration
Core Design Contradiction:
Manufacturing precisionVSLoss of time

Solution Approach 1:

The system performs self-calibration by automatically calculating the drag offset based on wheel spindown characteristics. The control system independently determines the correct actuator position without requiring manual intervention, thereby achieving precise positioning while eliminating time-consuming manual adjustment procedures.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The system replaces manual mechanical adjustment with an automated electronic control system. Instead of physically moving the actuator by hand, the system uses electronic sensors to monitor wheel spindown and electronically controls the actuator position based on calculated drag offset, achieving both precision and efficiency.

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

3Force

If the brake is over-pressurized to ensure stopping power, then the brake stops effectively, but the brake begins to drag and generate excessive heat

Engineering Contradiction:
Improvebrake stopping forceVSAvoidheat from brake dragging
Core Design Contradiction:
ForceVSObject-generated harmful factors

Solution Approach 1:

The system changes the actuator position parameter based on detected brake dragging conditions. By calculating the drag offset from wheel spindown characteristics and adjusting the actuator position accordingly, the system reduces brake pressure just enough to eliminate dragging and heat generation while maintaining sufficient stopping force through precise control.

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentEP2730474B1Automatic adjustment of electric brake actuators for a dragging brake condition
Publication Date: 2020.02.12 HAMILTON SUNDSTRAND CORP
  • EP2730474B1 patent drawingFigure 1
  • EP2730474B1 patent drawingFigure 2
  • EP2730474B1 patent drawingFigure 3

AI summary

A method of automatically adjusting at least one electric actuator, 52, of a brake, 42, to prevent dragging is provided including measuring a force applied by the at least one electrical actuator, 52, to a load measuring device. The measured force is determined to be below a predetermined threshold. A predefined offset is subtracted from a current zero torque position of the at least one electrical actuator, 52. Similarly, a drag offset is subtracted from the current zero torque position of the at least one electrical actuator, 52, to compensate for a dragging brake condition. The new zero torque positions is then stored within a brake actuator controller, 64, coupled configured to control the brake.