The CS Language Concept: A New Approach to Robot Motion Design

Abstract

Current robot control techniques are primarily concerned with position control and, recently, with force control, where a motion planner is used primarily to compute set point changes. The actual control system is fixed and internal and cannot be modified easily through software. Current robot languages are also limited in their ability to specify changes to the control structure. For compliant motion, such as as sembly, more flexibility is needed in the control system, that is, an ability to tailor the controller to the task. This paper develops a high-level control system (CS) language that allows one to specify compliant control tasks as vector equa tions and inequalities that relate sensed and controlled vari ables such as f · v = 0 and f X v = 0 . We show how such requirements can be reformulated as an objective function of an optimization process subject to constraints arising from the dynamic equations involved. Specifically for the two examples above, we show how such requirements can be re formulated as quadratic objective functions and solved using standard linear optimization theory for linear dynamic sys tems. Six examples are presented to illustrate the various ideas.