Robust design of high precision electromagnetic relay force measuement device

High reliability is required for mini-type electromagnetic relays, which is achieved by optimized cooperation of suction force provided by magnetic system and reaction loads providing by springs. Consequently, precise measuring on the suction force and the reaction force plays a key role in affairs with reliability involving in for the relay because 1) it provides a method to evaluate cooperation performance of suction and reaction inside the relay, and 2) it provides a possibility of screening test on the assemble pipeline for a higher consistency. Currently, methods for measuring suction and reaction are still in low accuracy and poor consistency, which is the main cause responding for relay´s low reliability. In this paper, an overall design is carried out to satisfy the requirements of the high-precision force measurement system based on theory of robust design. Then, central values are chosen for each component involved in this system. Key factors affecting output of the circuit are determined through parameter sensitivity analysis. Finally, tolerance design is performed based on key factors. The optimal solution is determined by compromising both the cost and the system performance. Performance improvement of the system before and after robust design indicates the validity of this method.