In the research area of virtual reality, the term haptic rendering is defined as the process of computing and generating the interaction force between the virtual object and the operator. One of the major challenges of haptic rendering is the stably rendering contact with a stiff object. Traditional haptic rendering algorithms performs well when rendering contact with soft objects. But when it is used to simulate contact with objects with high stiffness, the algorithm may cause unstable response of haptic devices. Such unstable behavior (e.g., oscillation of the device) can destroy the fidelity of the virtual environment and even hurt the user. To address the above stability issues, a new design approach has been proposed in this paper. The proposed approach consists of three main process steps: modeling and linearization in ADAMS, LQR position controller design, verification with co-simulation. In the first step, a simulation model of the system is firstly created in ADAMS/View. Then this nonlinear ADAMS multi-body dynamics model is linearized and exported as a set of linear state space matrices with the help of ADAMS/Linear. In the second step, different from the traditional force-control algorithms, LQR position controller is developed in Matlab Simulink based on the exported matrices to emulate interactions with stiff objects. At last, the verification of control performance is carried out by setting up co-simulation between ADAMS and Simulink. A case study implementation of this proposed method was performed on the TAU device which was previously developed by Machine Design department at KTH. TAU is an asymmetrical parallel robot with six degrees of freedom for the simulation of surgical procedures like drilling and milling of hard tissues of bones and teeth. The results show that the linear model exported from ADAMS is sufficiently accurate and the proposed controller can render a virtual wall with stiffness at the level of 105 N/m. ; Inom forskningsområdet virtuell verklighet definieras termen hatisk ...


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    Title :

    Control Implementation and Co-simulation of A 6-DOF TAU Haptic Device ; Reglering, implementering och samsimulering av en 6-DOF TAU haptisk enhet


    Contributors:
    Zhang, Yang (author)

    Publication date :

    2020-01-01


    Type of media :

    Theses


    Type of material :

    Electronic Resource


    Language :

    English



    Classification :

    DDC:    629