Development and Investigation of Semi-active Haptic Interfaces Using Digital Resistance Map Concept

The growing demand for haptic technologies in recent years has motivated novel approaches in developing haptic interfaces and control algorithms. Based on the force reflecting nature and energy flow directions, those interfaces are categorized in active and semi-active groups. Semi-active interfaces, in general, have the advantage of addressing safety concerns which adversely affects their active counterparts. This thesis presents the development of semi-active haptic interfaces using Magnetorheological (MR)-dampers. The ability of MR-Dampers in producing controllable resistance forces is the key reason for their utilization in interfaces. Our semi-active haptic interfaces are consisted of linear and rotary MR-Dampers. Each of the MR-Dampers is modeled using Bouc-Wen model. The parameters of the mathematical equation of the MR-Damper are identified experimentally. The concept of Digital Resistance Map (DRM) is developed as main strategy for activating MR-Dampers for semi-active interfaces. A preliminary study is carried out to verify the potentials of MR-Dampers and DRM for implementing in semi-active haptic system. Next, the DRM concept is expanded and introduced as a haptic rendering algorithm. The DRM is a high-fidelity haptic rendering algorithm and proved to be effective to create comprehensive force feedback for operators. MATLAB/Simulink is used for implementing several DRM scenarios for generating haptic enabled virtual environments. Several experiments are conducted to demonstrate the effectiveness of the interface and rendering algorithm. A human subject experiment is also included as a further investigation of the proposed system. The interface is integrated with virtual reality to provide the human operators with haptic and visual feedbacks. The obtained results confirm that the proposed system is able to generate understandable haptic and visual feedbacks to help the operators to explore virtual environments. Also, it is found that, to obtain the best human performances, haptic and visual feedbacks need to be combined.