Brake Actuator Position Correction for Thermal Expansion
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Solution Overview
Problem
Brake control systems in aeronautics face challenges due to component expansion during high-intensity braking, leading to a reduction in braking force due to heat-induced expansion of the torsion tube, which is not accurately accounted for by existing non-linear models.
Innovation Solution
A method that calculates a position correction to increase the force applied by the brake actuator by comparing the actual current with a reference current, using a correction formula that adjusts the nominal position setpoint to compensate for expansion, ensuring consistent braking force despite thermal expansion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the brake control system uses a non-linear model to determine the nominal position setpoint from the force setpoint, then the control precision is improved under normal conditions, but the reliability deteriorates during high-intensity braking due to thermal expansion of the torsion tube
Solution Approach 1:
The patent implements feedback by measuring the actual current consumed by the actuator motor and comparing it with the reference current calculated from the non-linear model. This feedback mechanism detects deviations caused by thermal expansion and triggers corrective action by adjusting the position setpoint to maintain the desired braking force.
Solution Approach 2:
The patent changes the operating parameters of the control system by introducing a position correction term that adjusts the nominal position setpoint. This correction is calculated based on the current difference and applied to compensate for thermal expansion effects, thereby maintaining braking force consistency under varying thermal conditions.
2Device complexity
If the actuator pusher position is controlled based on the non-linear model without compensation, then the device complexity is minimized, but the manufacturing precision deteriorates due to unaccounted thermal expansion effects
Solution Approach 1:
The patent replaces complex mechanical compensation mechanisms with an electronic control solution. Instead of using mechanical elements to physically compensate for thermal expansion, the system uses electronic sensors, processors, and control algorithms to detect and correct position deviations, thereby maintaining precision without adding mechanical complexity.
Solution Approach 2:
The patent introduces an intermediary computational layer that processes the relationship between force setpoint, actual current, and position setpoint. This intermediary control algorithm acts as a mediator between the desired braking force and the actual actuator position, compensating for thermal expansion effects through calculation rather than direct mechanical intervention.
3Reliability
If the position correction is applied to compensate for thermal expansion, then the braking force consistency is improved during high-intensity braking, but the device complexity increases due to additional correction calculations and current measurements
Solution Approach 1:
The patent implements a self-service control mechanism where the system uses its own operational data (actual current consumption) to automatically detect and correct deviations from the desired braking force. The control algorithm self-adjusts the position setpoint based on real-time feedback, eliminating the need for external intervention or complex additional sensing systems.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This method effectively maintains consistent braking force by accounting for thermal expansion, enhancing the reliability of brake control systems during high-intensity braking conditions by compensating for the limitations of existing non-linear models.
Implementation Method 1
an electric motor (not shown) for driving the pusher (13)
Implementation Method 2
the heat given off by the friction elements of the brake is very high and risks leading to an expansion of the torsion tube on which the friction elements are mounted
Data Source
AI summary
The method involves determining a normal position set point of a braking actuator from a braking set point. A reference current circulating through an electric motor of a hydraulic or electromechanical brake actuator is estimated from the braking set point to apply an effort equal to the braking set point. The reference current is compared to a current circulating in the motor of the actuator, and a position correction (Xcorr) is deduced. The correction of the position is added to the normal position set point. An independent claim is also included for a device for controlling electromechanical braking of a wheel of a vehicle.