Perceptual performances of force rendering methods

In virtual reality techniques, the force feedback method becomes important especially when manipulating shapes interactively. This paper describes two methods for presenting haptic stimuli, and compares their perceptual effects. One of the methods involves generating undulations by spatially varying the positions where reaction forces are generated while keeping their directions constant, and the other method involves spatially varying the directions of reaction forces while keeping the positions constant. The subjective intensities of undulations generated by the two methods were compared. The results indicated that the subjective intensities depend on their spatial frequencies. Then, two stimuli were superimposed 180 degrees out of phase to check if the two stimuli generated by different methods offset each other. No offset was observed regardless of the spatial frequencies of the stimuli