Study of a Hall Effect Brake Wear Sensor using Finite Element Modelling and Analysis

C. S. Anoop, Boby George

Abstract

Monitoring of brake wear and warning the driver to replace it at the appropriate time is a critical safety requirement. Recently, basic concept of a new, simple and low-cost Hall-Effect (HE) based angle sensor, which continuously monitors brake wear, by sensing the angle rotated by the Cam Shaft (CS) with-respect-to the Slack Adjuster (SA) in the brake assembly has been presented. The sensor has a spiral shaped moving part. It rotates along with CS, and changes the magnetic field seen by a HE sensor, whose output is directly proportional to angle between CS and SA, for a wide range. A prototype angle sensor has been developed, and test results showed a linear range of 220°, which is sufficient for monitoring brake wear. In the sensor, parameters like positioning of the HE sensor, relative permeability of the materials used, thickness of the moving part, etc. play a crucial role as far as the linearity of output and sensitivity are concerned. Sensor optimisation based on hardware implementation is time consuming, inefficient and less accurate. Hence, a finite element model of the sensor has been developed, and various studies have been conducted to optimise the parameters for best performance of the sensor. This also enables to achieve a linear output without using complex circuitry.

Keywords

brake-wear sensor, Angle Sensor, Hall Effect, Spiral, Through-Shaft sensing

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IMEKO TC

TC4 - Measurement of Electrical Quantities

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