Force Feedback in String based Haptic Systems

In this paper the force feedback computation is investigated for improving the quality of the haptic feedback in virtual reality applications. The chosen structure for the force feedback device is string based and characterized by 3 degrees of freedom (force-feedback only) or 6 degrees of freedom (force and torque feedback). This haptic device is used together with a three-sided stereoscopic immersive visualization system to convincingly create sensations associated with forces and also with the shape and texture of the displayed objects. Feelings in general are not easy to simulate by computer technology and haptic information (force and torque feedback) can be distorted by incorrect distribution of the tension forces in the strings or delays in the computation process, because it must be updated at very high rate (approximately 1000 Hz). In this paper a new method is suggested, in which the number of computation step is fixed and the amount of calculation is low and always limited.