Vibration isolation system using spring actuator with iron particle layers stacked with permanent magnet and electromagnet under disturbance cancellation control

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 vibration isolation control is presented using the actuator. In the control, only the disturbance of base is detected, and the disturbance cancellation control is performed. Especially, the system requires no state variables of the vibrating body, and the transmissibility is almost zero in wide frequency ranges.