Control of nonlinear mechanical systems

Summary form only given, as follows. Many interesting and practically relevant mechanical control systems are highly nonlinear. Typical examples are often encountered in robotics (rigid robots, mobile robots, . . .), aerospace (spacecrafts) and marine technology (ships, submarines, . . .). Even the control of relatively simple linear mechanical systems is often complicated by the fact that an undesirable nonlinear effect as fiiction is present. The purpose of the talk is to give a survey on nonlinear control with an emphasis on trajectory tracking of nonlinear (mechanical)systems. This will include standard linearization methods, input-output decoupling techniques, and more advanced state trajectory tracking feedback designs. In the context of mechanical systems attention is paid to the class of fully actuated systems, but also to first and second order nonholonomic systems; typical examples of the latter classes are mobile robots and underactuated rigid robots. Since in many cases only partial state information is available it is often desirable to develop output feedback, or observer based, tracking control hemes. This aspect will be addressed in the presentation in a number of particular cases. Experimental results on tracking control of a scaled model of a supply vessel will be given as illustration of advanced nonlinear controller design.