Modeling and control of a flexible structure incorporating inertial slip-stick actuators

Shape and vibration central of a linear flexible structure by means of a ne w type of inertial slip-stick actuator are investigated. A nonlinear model representing the interaction between the structure and a six-degree-of-free dom Stewart platform system containing six actuators is derived, and closed -loop stability and performance of the controlled systems are investigated. A linearized model is also derived for design purposes. Quasistatic alignm ent of a payload attached to the platform is solved simply by using a propo rtional controller based on a linear kinematic model. The stability of this controller is examined using a dynamic model of the complete system and Is validated experimentally by introducing random thermal elongations of seve ral structural members. Vibration control is solved using an H-infinity loo p-shaping controller and, although its performance is found to be less sati sfactory than desired, the nonlinear model gives good predictions of the pe rformance and stability of the closed-loop system.