Robust multivariable nonlinear control of a two link excavator. I

The design of controllers to achieve stability, regulation and tracking for multilink excavators is an open control problem due to the many nonlinear effects that have a dominant role within the wide region of link motions. A design model and a nonlinear polar controller are developed for the Caterpillar 325 excavator modeled as a two-link system. Described here are the 8th order model of excavator dynamics, the structural properties of this model, and the 4th order design model of the link dynamics employed in the development of the polar controller.