Development system for a haptic interface based on impedance/admittance control

Abstract

There are two fundamental and dominant control methods widely used in haptic controller design. First, is impedance control when user motion input is measured and the reaction force is fed back to user. The alternative method is admittance control, when forces exerted by user are measured and positions are fed back to user. Both, impedance and admittance control are also fundamental ways for interacting with a virtual environment. In This work, impedance control is investigated experimentally from the viewpoint of suitability for haptic interface development. The difference between conventional application of impedance control in robot motion control and its application in haptic interface development is investigated. Open loop impedance control methodology is implemented for static case and a general-purpose robot under open loop impedance control was developed as a haptic device, while a closed loop model based impedance control was used for haptic controller design in both static and dynamic case. The factors that could affect to the performance of a haptic interface are also investigated experimentally using parametric studies. The investigation is carried out on a HIL experimental setup and is verified that the HIL experimental set up can be used as a generic platform for the development and for testing haptic interface options before prototypes are built. Experimental results for 1 DOF rotational motion and 2 DOF planar translational motion systems are presented.