PASSIVE DYNAMIC CONTROLLERS FOR NONLINEAR MECHANICAL SYSTEMS

A methodology for model-independent controller design for controlling the large angular motion of multibody dynamic systems is outlined. The controlled system may consist of rigid and flexible components that u ndergo large rigid body motion and small elastic deformations. Control forces/torques are applied to drive the system and at the same time s uppress the vibrations due to flexibility of the components. The propo sed controller consists of passive second-order systems that may be de signed with little knowledge of the system parameters, even if the con trolled system is nonlinear. Under other general assumptions, the pass ive design assures that the closed-loop system has guaranteed stabilit y properties. Unlike positive real controller design, stabilization ca n be accomplished without direct velocity feedback. In addition, the s econd-order passive design allows dynamic feedback controllers with co nsiderable freedom to tune for desired system response and to avoid ac tuator saturation. After developing the basic mathematical formulation of the design methodology, simulation results are presented to illust rate the proposed approach applied to a flexible six-degree-of-freedom manipulator.