Controlling more with less using nonholonomic gears

Abstract

This paper addresses the use of nonholonomic gears in robotic applications to reduce the number of actuators necessary to control a given system. Previous research by (Sordalen et al., 1994) has shown that an n-degree of freedom robot can be controlled using only two actuators. This paper focuses on the advantages of using three or more actuators to control a system of nonholonomic gears, and derives the principles for doing so. In particular, it shows that using one or two additional actuators aids in reducing the complexity of the control laws, while at the same time increasing the number of degrees of freedom that can feasibly be controlled. The paper illustrates the ideas using three novel proposed systems: a three-degree of freedom reorientable table, a six-degree of freedom mobile manipulator, and a (human) head-driven feeding device for quadraplegics.