PFI:AIR - TT: Non-Intrusive Position Measurement in Oscillating Piston Applications

University Of Minnesota-Twin Cities, Minneapolis MN

Investigators

Abstract

This PFI AIR Technology Translation project focuses on translating research for determining the spatial location of a magnet into technology to fulfill the need for piston position measurement in piston-cylinder actuators. The developed sensor is important because it can enable automation in a number of industrial and mobile machines. The project will result in a robust prototype of a piston position measurement sensor. The proposed sensor will be non-contacting, non-intrusive, inexpensive, will not require line-of-sight access, and will involve minimal effort for installation on a cylinder. Due to these advantages, the proposed sensor has an opportunity to establish a significant market share in the piston position application domain. This project addresses the following technology gaps as it translates from research discovery towards commercial applications: a) The need to place the sensor at an off-axis location on top of the actuator requires the development and use of complex two-dimensional magnetic field models. b) The sensor prototype needs to address problems due to hysteresis when the cylinder is made of soft steel which gets magnetized and demagnetized in real time due to oscillatory motion of a magnet. c) Extension of the previous linear position sensor technology to rotational applications requires new sensor architectures, development of new models, and new estimation algorithms. Specific solutions to address the above challenges will be fully developed and evaluated in the project. The proposed solutions include development of analytical two-dimensional magnetic field models, development of a new analytical model for hysteresis that has significant advantages over the traditional Preisach model, and development of robust auto-calibration algorithms. In addition, a graduate student and a post-doc involved in the project will receive technology translation experience through prototype development and industrial interaction. The project engages three major actuator companies to evaluate the sensor prototype on their actuator products, as the technology is translated from research discovery towards commercial reality.