Abstract
This note is concerned with direct design of a robust second order controller for linear mechanical systems whose motion equations can be described by second order differential equations with symmetric, positive (semi) definite coefficient matrices. Only the displacement measurements are supposed to be available and the sensor/actuator are only required to be collocated in a wide sense. Conditions are made clear under which the overall closed loop system is guaranteed to be robustly stable. The obtained results are a supplement to the paper by Juang and Phan3).
