A Passivity-based Approach For Stable Patient-Robot Interaction In Haptics-enabled Rehabilitation Systems Modulated Time-domain Passivity Control M-TDPC
In this paper, a novel passivity-based technique is proposed to (a) analyze and (b) guarantee the stability of haptics-enabled robotic/telerobotic systems when there is a possibility of having a source of nonpassivity (namely, a nonpassive environment) in addition to the conventional nonpassive component in teleoperation systems (namely, a delayed communication channel). The need for the proposed technique is motivated by safe and optimal implementation of haptics-enabled robotic, cloud-based and remote rehabilitation systems. The objective of the controller proposed in this paper is to perform minimum alteration to the system transparency, in a dynamic and patient-specific manner, by utilizing quantifiable biomechanical capability of the user’s limb (i.e. Excess of Passivity) in dissipating interactive energies to guaranteeing human-robot interaction safety, in the context of the Strong Passivity Theorem (SPT). The proposed controller is named Modulated Time-Domain Passivity Control (MTDPC) approach and is a new member of the family of stateof- the-art TDPC techniques. Simulations and experimental results are presented in support of the proposed technique and the developed theory.