Direct disturbance cancellation with an optimal regulator for a vibration isolation system with friction

A method is presented for direct disturbance cancellation with an optimal regulator for a vibration isolation system with friction. As an example, a DC servomotor is considered as an actuator. The analytical expressions for the control method are first derived. Results of experimental tests are also presented, and it is shown that the present method has advantages as compared to the usual active vibration isolation control methods. For the usual vibration isolation control systems, the maximum transmissibility is greater than or equal to unity, while when the present method is used the transmissibility becomes less than 20 percent of the external disturbance for a practical system with friction. When there is no friction, the transmissibility will, of course, become smaller.