Dynamic Analysis of Noncollocated Flexible Arms and Design of Torque Transmission Mechanisms

A new actuation method for one-link flexible arms is presented. The endpoint control of a flexible arm has been known to be a nonminimum phase system due to the noncollocated sensor and actuator. By relocating the actuator near the endpoint, the system can be changed to a minimum phase system. In order to implement this, transmission mechanisms are developed which transform the actuator torque to appropriate force and torque and transmit them to an appropriate point on the arm link. Exact pole-zero configurations are analyzed with regard to the location of the actuation point and the type of transmissions. We then develop an integrated design method, which allows for relocating zeros for an improved control performance. A prototype flexible arm is designed based on the design guidelines and open loop and closed loop tests are made to verify the effectiveness.