Research On The Optimization And Composite Characteristics Analysis Of The Electromagnetic Actuator

Electromagnetic actuator, which has advantages including fast response, considerable control force, non-contacting, manageable, etc, is one of the most commonly used and important elements in active vibration isolation technology. According to the variation of external disturbance force frequency, electromagnetic actuator will change excitation current when it is working, and adjust natural frequency of the actuator so as to track the frequency of external disturbance force. The structure parameters and adjusting range of frequency for the electromagnetic actuator should be determined the object of vibration reduction. The active vibration isolation technology puts forward higher requirements to the performance of electromagnetic actuator, such as larger electromagnetic force, lower temperature rise, faster dynamic response and nice linear steady characteristics, with the purpose of achieving good vibration isolation effect. Therefore, in order to meet. the system requirements, it is necessary to consider comprehensively to the dynamic and steady characteristics of electromagnetic actuator and multi-objective optimize to the structure parameters of the actuator.This paper introduces the basic structure and the work principle of the electromagnetic actuator firstly, and then, establishes a electromagnetic actuator simulation model by means of applying software and finite element method. The influence of structure parameters, such as tooth width and pitch, backlash and number of teeth, on static characteristics of the electromagnetic actuators is analyzed through the simulation of static characteristics, which is a foundation for the building of the optimization model.Secondly, dynamic simulation is conducted by using the simulation model of electromagnetic actuator in Ansoft software Maxwell environment. The influence of different parameters on dynamic characteristics of electromagnetic actuator are analyzed by changing parameters such as the driving voltage, mass of moving part, spring stiffness,spring pre-tightening force and the numbers of the coils. The curves of electromagnetic force, displacement and current change with time are obtained from the simulation results,and so it is the response time under various parameters. Outputs of the system when different parameters add or subtract a unit variable are obtained under various operating conditions by the simulation, and then the sensitivity matrix of optimization model of the system can be calculated, which provides good basic to optimize the system.Then, the output matrix, parameters matrix, input matrix and target output variables matrix of the system are developed, and the optimization model of the system is obtained by means of Taylor expansion. Using the least square method to solve the optimization model,and optimize the electromagnetic force and response time of the electromagnetic actuator under various operating conditions. The optimization results show that this optimization method is simple, effective and applicable.In the end, using the genetic algorithm of multi-objective optimization calculate the optimization model. The basic concept and operation process of genetic algorithms are introduced. Adaptive weighting method in the multi-objective optimization has been given,which can be used to transform the optimization model. To transform the function of multi-objective optimization to a single objective functions and optimized, and realize the genetic algorithm using MATLAB software.