Real-time control of a nonlinear electromagnetic actuator

Abstract

This paper describes theoretical and experimental investigations aimed at controlling the trajectory of a nonlinear, clapper-type electromagnetic actuator. The vehicle for the investigations is the three-piece actuator used in the IBM 4248 impact line printer. The control algorithm seeks to regulate flight time-the time required for the actuator to move from its rest position to its point of impact-by modulating the pulse width delivered to the coil as a function of one measurement of position and velocity. The actuator is modelled mathematically, and a control law based on initial conditions is numerically derived. A similar control law based on mid-flight conditions is derived experimentally, by computer-controlled adaptation, and its ability to regulate flight time is demonstrated. © 1989.