Research On Aerospace Electromagnetic Relay Robust Design

Aerospace electromagnetic relay (EMR) is widely used in automatic field such as missiles, launch vehicles, satellites, spacecrafts, space shuttles and their matching ground equipments, to accomplish signal transduction, control execution and power distribution, etc. It is one of main electronic components in national defense electronic systems, whose reliability influences directly the reliability of the whole national defense electronic systems. Generally, EMR is believed to be a least reliable electronic component in control systems. The study on EMR reliability shows significant economic and social benefits for our society. According to the present problems in reliability design of EMR that the design theory has not been consummated, which has led to the low noise immunity of EMR output characteristics, this paper has optimized the parameters values and their tolerances, adopting Taguchi's robust design method, to improve the EMR's reliability.Dynamic characteristics calculation is the basis of the research. The dynamic characteristics of EMR are calculated theoretically using magnetic circuit method, based on establishment of dynamic characteristics mathematical model of EMR. The finite element model of EMR electromagnetic system is built with FLUX software, and is simulated with transient analysis function to obtain the dynamic characteristics results. The multi-body dynamics model of EMR mechanical system is built with ADAMS software, and is simulated to obtain the dynamic characteristics results. Then the method to get the contact breaking velocity and contact collision velocity is proposed. The simulation results have verified the validity of theoretical calculation, and provided guarantee for the accurate calculation of the experimental study.In process of robust parameter design, through analyzing the electric arc which has significant influence on EMR's working life, the objective functions are determined as contact breaking velocity, contact collision velocity and armature collision velocity. Based on dynamic characteristics calculation of electromagnetic system by magnetic circuit method, the key design parameters are determined by analysing the influence of electromagnetic system parameter values continuous variation on objective functions. The internal-external orthogonal tables are used for experiment planning, and the simulation softwares are used for calculating the EMR's dynamic characteristics. The optimal combination of electromagnetic system parameter values is obtained by signal noise ratio and sensitivity variance analysis methods. Finally, the result is verified by experiment that having a better output characteristics and resistance than before.In process of robust tolerance design, orthogonal tables are used for experiment planning, and the simulation softwares are used for calculating the EMR's dynamic characteristics. The tolerance design formulas of electromagnetic system and contact spring system is obtained respectively by contribution rate analysis method, which is used for estimating the rationality of tolerance distribution existing. Taking the dispersion degree reduce to 50% of the original as the design objective, the improvement scheme of electromagnetic system and contact spring system are designed preliminary, whose feasibility can be validated from economic point when the relationship between parameters'tolerances and product cost or processing capacity are given.This paper has provided necessary tools and methods for aerospace EMR's robust design, which can also be applied to other electric product design processes. At present, the research results of this paper are applied to improve the reliability of the aerospace EMR of some type.