Thrust simulation of a linear oscillatory actuator

This paper describes thrust simulations using the finite element method (FEM) for two types of linear oscillatory actuators (LOAs) to be used as a linear pulsator in a milking machine. The LOAs are cylindrical and have a moving core which is driven at low frequencies in the range of 0.6-1.2 Hz. The first one of the LOAs (named LOA-94) has a maximum thrust of 8.2 newtons and the simulation results approximately coincide with the measured values in the displacement range of /spl plusmn/2 mm. The second one (named LOA-95) has a maximum thrust of 8.9 newtons and the simulation results agreed with the measured values within the error of 25 % at the displacement of x=-0.5 mm. In comparison of the stroke-load characteristics between two LOAs, the second actuator (LOA-95) is more stable than that of first actuator (LOA-94) with respect to change in the load.