| Abstract: | In this article we explore, both theoretically and experimentally, the effect of multiple structural compliance sources on robot stability during contact task execution. Here we examine the effect of link compliance and compliance of the contact surface on overall system stability. Using the theory associated with singularly perturbed dynamic systems, the stability of the robotic system is examined for three distinct cases: (1) link stiffness much greater than contact surface stiffness; (2) contact surface stiffness much greater than link stiffness; and (3) link stiffness comparable to surface stiffness. Theoretical results lead to a conclusion of stability only for case (1). Experiments indicate stable behavior for all these cases. Through the use of singular perturbation modeling and analysis, we are able to write dynamic models of the robot during contact with a complaint surface such that the complaint behavior of the robot links and contact surface are parameterized with just two variables. In doing so, theoretical examination and experimental study of stability, or the lack thereof, is greatly simplified. Instead of exhaustive tests in which experiments or stability analyses are conducted over a wide range of values of link and contact surface compliance, a select number of cases are examined. Under the assumptions that validate the use of singular perturbation modeling techniques, the resultant stability analysis and experimental results are hence conducted in an efficient manner. © 1997 John Wiley & Sons, Inc. |
