Portable Two-Dimensional Direction Indicator with a Pseudo-Attraction Force

This paper describes a portable force-feedback device based on asymmetric oscillation that exploits the characteristics of human perception. Our previous results with a one-degree-of-freedom prototype device indicated that the kinesthetic illusion of being pulled is effectively generated within proper frequencies in one direction. The objective of this study is to develop a portable device that presents haptic information in any arbitrary direction on a two-dimensional plane. A 12-cm-diameter haptic display was designed and built. In the display, the single-speed rotational cyclic movement of the motor is converted into asymmetric translational cyclic movement with asymmetric acceleration via a hybrid configuration comprising cam and swinging slider-crank mechanisms, tricking the user into perceiving a unidirectional force. A haptic display that accommodates four hybrid-mechanism modules has been implemented. The perceived force direction is determined by combining force vectors generated by each module in the force display. The design reduces the size of the haptic display and gear noise. The results of a psychophysical experiment suggest that people who hold the device can perceive the predefined directional force intuitively.