Brake Air Gap Estimation via Position Sensor Cycling
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Solution Overview
Problem
Existing brake systems face challenges in accurately estimating and adjusting the air gap between brake friction members and pad assemblies due to factors like wear, temperature changes, and sensor noise, leading to potential braking performance issues.
Innovation Solution
A method and system that utilize a position sensor and actuator pressure signals to indirectly estimate the air gap and adjust it when necessary, using an air gap adjustment mechanism to maintain a desired gap, thereby compensating for variations and ensuring optimal braking performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a position sensor is used to detect brake pad assembly position, then the air gap can be estimated, but sensor noise and drift affect measurement precision
Solution Approach 1:
The system continuously monitors the position sensor signal during brake cycling and compares it against expected position changes. When drift or noise is detected, the system adjusts the air gap estimation by compensating for the detected error, creating a closed-loop feedback mechanism that maintains measurement accuracy despite sensor imperfections.
Solution Approach 2:
The brake system performs self-diagnosis by monitoring its own operational parameters. The position sensor data is analyzed during normal brake cycling to detect drift patterns, and the system automatically compensates for this drift without external intervention, allowing the system to maintain accuracy through its own operational data.
2Reliability
If the brake pad assembly is cycled frequently to maintain air gap, then braking performance is maintained, but wear and energy consumption increase
Solution Approach 1:
Instead of continuously cycling the brake pad assembly, the system performs partial cycling actions only when necessary to correct air gap deviations. The controller analyzes position sensor data and triggers adjustment cycles only when the air gap falls outside acceptable ranges, reducing unnecessary energy consumption while maintaining braking performance.
Solution Approach 2:
The system implements periodic monitoring of the air gap using the position sensor during normal brake operations. Rather than continuous adjustment, the system performs discrete air gap measurements and adjustments at periodic intervals based on brake usage patterns, optimizing the balance between performance maintenance and energy efficiency.
Data Source
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AI summary
A method of controlling a brake system comprising: cycling a friction brake; indirectly estimating an air gap between a brake friction member and a brake pad assembly based on a position signal from a position sensor that detects cycling of the friction brake and a further signal indicative of an amount of brake force used to engage the brake pad assembly with the brake friction member; and adjusting the air gap when an estimated air gap differs from a desired air gap.