Haptic guidance in a collaborative Robotic system

Abstract

The development of the notion of virtual fixture originated the broader concept of robot haptic guidance, meaning a recent technology to support motor learning. It has been applied in many areas, namely on automotive assembly, medical rehabilitation and training of healthy people. The implementation of virtual fixtures depends on the robot mechanical and drive system, namely the type of actuators and transmissions. If non-backdriven transmissions are used the operator controls the robot through the forces he/she exerts on the robot handle (which are measured by a force transducer incorporated at the robot end-effector). These robots usually use motors with large reduction ratios and are admittance controlled. In this paper we implement haptic guidance in an impedance type three degree-of-freedom (dof) heavy robot. An admittance low-level controller is firstly designed based on an IP (Integral, Proportional) velocity controller. Two types of virtual fixtures are implemented and the effectiveness of the proposed approach is illustrated experimentally. © Springer-Verlag Berlin Heidelberg 2013.