Stability of Cooperative Teleoperation Using Haptic Devices with Complementary Degrees of Freedom

In bilateral teleoperation of a dexterous task, to take full advantage of the human’s intelligence, experience, and sensory inputs, a possibility is to engage multiple human arms through multiple masters (haptic devices) in controlling a single slave robot with high degrees-of-freedom (DOF); the total DOFs of the masters will be equal to the DOFs of the slave. A multi-master/single-slave cooperative haptic teleoperation system with w DOFs can be modeled as a two-port network where each port (terminal) connects to a termination defined by w inputs and w outputs. The stability analysis of such a system is not trivial due to dynamic coupling across the different DOFs of the robots, the human operators, and the physical or virtual environments. The unknown dynamics of the users and the environments exacerbate the problem. We present a novel, straightforward and convenient frequency-domain method for stability analysis of this system. As a case study, two 1-DOF and 2-DOF master haptic devices are considered to teleoperate a 3-DOF slave robot. It is qualitatively discussed how such a trilateral haptic teleoperation system may result in better task performance by splitting the various DOFs of a dexterous task between two arms of a human or two humans. Simulation and experimental results demonstrate the validity of the stability analysis framework.