Dr. Perry Li

Mechanical Engineering

University of Minnesota


“Coordination of multiple mechanical systems with passivity”

 Many applications involve requiring two or more mechanical systems to work in coordinated manner. When the system of interest requires interacting with the external physical world, maintaining a certain passivity property with respect to these physical interaction variables is useful for enhancing interaction stability and safety etc. In this talk, we will discuss a technique for decomposing the dynamics and energetics of the multiple mechanical systems into the coordination and formation aspects, each having dynamics and energetics reminiscent of a mechanical system. The decomposition enables us to design controllers for the coordination and the formation aspects separately while preserving passivity. We will address two example - mechanical teleoperators (more details) and hierarchical formation flight (briefly). In the case of the teleoperator, the control renders the system to behave like a passive mechanical tool; in the case of the formation flight, the approach enables a natural hierachical groupings and separate control of the formation and group maneuver. The geometric interpretation of the control approach will also be discussed.