On the Spatial Compliance of Robotic Manipulators

Abstract

Interactive control schemes, such as stiffness control and impedance control, are widely accepted as a means to actively accommodate environmental forces, but have not been widely applied. This is in part because well-known controllers are parametrized in a mathematically convenient, but nonintuitive way. “Spatial compliance control” is a Euclidean-geometrical version of compliance control that is parametrized in an intuitive way. A family of compliances is introduced with spatial transformation properties that simplify spatial reasoning aspects of compliance parameter selection. A control law is derived assuming that the robot consists of a serial linkage of rigid links actuated by variable-effort actuators.