POSITION CONTROL OF SINGLE LINK FLEXIBLE MANIPULATOR BY VARIABLE-STRUCTURE MODEL-FOLLOWING CONTROL

A variable structure model following controller (VSMFC) is designed fo r the tip position control of a single flexible link. The design is do ne for the system model in which only the first two flexible modes are included. Due to the simplicity in choosing second order models for t he subsystems representing the dynamics of the various flexible modes, the design cart be easily extended to include any desired number of f lexible modes. The tip position response is made to assume a second or der step response by suppressing the flexible modes very quickly. Henc e the tip position response can be easily controlled by a suitable cho ice of the damping factor and natural frequency of the second order mo del which the rigid body mode of the link is made to follow. The contr oller is robust to parameter variations and disturbances.