Design and Preliminary Evaluation of High-Temperature Position Sensors for Aerospace Applications

In this paper, high-temperature position sensors for aerospace applications are proposed and geometric design improvements to enhance the performance of the proposed position sensors are derived. Position sensors comprise a resistive element, a conductive brush that moves along the resistive element, and the electrodes at each end of the element. In design of conventional position sensors, the resistive elements are exposed to the atmosphere. This exposure results in oxidation and a chemical reaction with ambient gas at a high temperature. Furthermore, the resistive elements can be damaged by the brush, which is in direct contact with the surface of the resistive element. Materials used for the resistive element, electrode, and substrate limit high-temperature applications of conventional position sensors. To overcome these disadvantages associated with conventional position sensors, novel position sensors were designed that focus on the protection of the resistive elements and the selection of high-temperature materials for the resistive element, electrode, and substrate. The spatial resolution of the proposed position sensors can be improved by densely integrating the patterns of the position sensors using the planar process, which is used to realize microelectromechanical systems and IC devices. In this paper, two types of position sensors were fabricated, and a preliminary performance evaluation at room temperature was carried out in order to validate the concept of the proposed potentiometers; the results of the performance test are presented in this paper.