Design of Electromagnetic Linear Actuator Using the Equivalent Magnetic Circuit Method

This paper analyzes the design variations of an electromagnetic linear actuator with a divided coil excitation system, such as the colenoid system, using the equivalent magnetic circuit (EMC) method. First, the magnitude and direction of magnetic flux for each pole can be obtained using the EMC method, while the magnetic flux density for each pole is calculated using the superposition principle. To make the magnetic flux density uniform at each pole, the pole width is adjusted by the iteration method. The generated clamping force of the optimized model with EMC has almost the same force characteristics as the optimization results based on the finite-element analysis. By the proposed EMC method, the characteristics of the electromagnetic linear actuator with variations in the slot width and current are investigated. An electromagnetic linear actuator is also developed to produce a clamping force of 35 kN, and the experimental results show that it can be used to hold a workpiece firmly instead of using a hydraulic cylinder in a chucking system.