Construction of Interaction Parallel Manipulator: Towards Rehabilitation Massage

A massage robot can aid physicians in treating occupational diseases. While massaging, a robotic manipulator is required to continuously exert desired force according to the predefined motion pattern on a body surface. The complexity of the mechanical and control system, high cost, and heavy structure of the existing massage robots result in the limitation of widespread applications at home or small clinics, and some of which can just implement a single massage task. This becomes even more challenging how to integrate multiple massage functions into one robotic system deployed at home or small clinics. To tackle the abovementioned problems, we propose a parallel-mechanism-enabled massage end-effector with compliant joints based on the series elastic actuators, offering a unified force-position control approach and enabling to easily coordinate multiple degrees of freedom. First, the kinematic and static force models are established for obtaining the corresponding control variables. Then, a novel force-position control strategy is proposed to separately control the force-position along the normal direction of the surface and another two-direction displacements, without the requirement of a robotic dynamics model. To evaluate the performance of the proposed massage manipulator, we implement a series of robotic massage experiments and also, carry out a user study. The corresponding results demonstrate that the proposed massage manipulator can successfully achieve desired forces and motion patterns of massage tasks, arriving at a high-score user experience.