Abstract: A new spring type actuator is presented in which controls are
possible by using usual control methods such as PID control. The actuator
consists of a normal helical coil spring and a number of iron (ferrite)
particles layers inside. The iron particles layers are made of silicon based
adhesive material involving iron particles. The layers are pasted to the coil
spring with a certain air gap between each layer. To achieve both extensive and
compressive motions, a permanent magnet is attached to the top of the spring
and electromagnet to the base, and the motion of the top of the actuator is
controlled by electric currents in the coil of the electromagnet. A method of
forming the actuator is presented, and its design formulae are presented. The
present actuator works well under the control. Especially, the size is small in
comparison with such as moving coil actuators and the work area is large
enough.
Keywords: Spring, actuator, electromagnet, control, iron particles layer
