Modelling and control of a haptic interface, a mechatronics approach

Abstract

With the advent of virtual reality and the increasing power of modern computers, there is renewed interest in new modalities for the human-machine interface. Force feedback is gaining momentum as new applications of teloperation and haptic devices are discovered. This work applies the principles of mechatronics to the design and control of a novel five-bar robot for use as a haptic interface. Since the robot includes flexibility, a general model for a two degree-of-freedom flexible link mounted on an arbitrary robot is developed. The model highlights the contributions of the flexibility to the overall dynamics and presents the dynamics in a matrix form. System identification is performed to isolate the model parameters for the robot and particular attention is paid to Coulomb friction. The model is then used to develop a non-linear state estimator. The estimator is applied to the problem of implementing a virtual wall and the results are shown to be superior to conventional techniques. The importance of the mechatronics approach is highlighted throughout. Frameworks for optimal implicit force control and impedance control are also developed and experiments performed.