On the Optimum Dimensioning of Robotic Manipulators

摘要

Abstract. The design of robotic manipulators begins with the dimensioning of the various links to meet performance specifications. However, a methodology for the determination of the manipulator architecture, i.e., the fundamental geometry of the links, regardless of the shape of these, is still lacking. Attempts have been made to apply the classical paradigms of linkage synthesis for motion generation, as in Burmester Theory. The problem with this approach is that it relies on a specific task, described in the form of a discrete set of end-effector poses, which kills the very purpose of using robots, namely, their adaptability to a family of tasks. Another approach relies on the minimization of the condition number of the Jacobian matrix over the architectural parameters and the pose variables of the manipulator. This approach is not trouble-free either, for the matrices involved can have entries of different units, the matrix singular values thus being of disparate dimensions, which prevents the evaluation of the condition number. As a means to solve the dimensional-inhomogeneity problem, the concept of characteristic length has been put forth. However, this concept has been slow in finding acceptance within the robotics community, probably because it lacks a direct geometric interpretation. In this paper the concept is revisited and given a simple geometric interpretation. The application of the concept to the design and kinetostatic performance evaluation of serial robots is illustrated with examples. 1.