A general framework is presented for the design and analysis of cobot controllers. Cobots are inherently passive robots intended for direct collaborative work with a human operator. While a human applies forces and moments, the controller guides motion by tuning the cobot's set of continuously variable transmissions. In this paper, a path-following controller is developed that steers the cobot so as to asymptotically approach and follow a preplanned path. The controller is based on feedback linearization. Generality across cobot architectures is assured by designing the controller in task space and developing transformations between each of four spaces: task space, joint space, a set of coupling spaces, and steering space.
R. Brent Gillespie, J. Edward Colgate, Michael A.