Design and modeling of a 2-DOF hybrid haptic joystick with the use of pneumatic muscles and magnetorheological spong cell

In this paper, a two-degree of freedom hybrid haptic joystick excited by pneumatic muscles is designed in which the feedback force is simulated by a foam impregnated with magnetorheological fluid. The purpose of this article is to design a remote surgical training device to simulate the stiffness of various tissues of the body. The joystick is designed to simulate the various body tissues which requires intelligent force feedback. Due to the different mechanical behavior of various tissues of the body, the force feedback mechanism should be able to simulate the behavior of the desired tissues and change the state. Therefore, an open-cell polyurethane foam impregnated with a magnetorheologic fluid has been used. The joystick is excited by artificial pneumatic muscles. stress-strain behavior of two tissues are examined and simulated by the MR fluid impregnated foam in a given magnetic field. In equilibrium state for a given tissue, the relation between the magnetic field and the strain is obtained. According to the simulation results, in high stresses, foam with a larger Elastic modulus and MR fluid with higher volume fraction of magnetic particles should be used. It is shown that the proposed MR sponge cell can effectively represent different reaction force of the specimens by applying different magnetic intensity to the cell domain.