Temporal characteristics of non-grounded translational force and torque display using asymmetric vibrations

We propose a device that can display translational force and torque by using two vibration speakers. Each vibration speaker generates an asymmetric vibration when a sound with an asymmetric amplitude is inputted. Asymmetric vibrations induce perceived forces that pull or push a user's hand in a particular direction. The user can perceive translational force and/or torque with his/her thumb and index finger based on the direction and amplitude of each speaker's force. In this study, the shortest time period of direction discrimination and time series variation of the perceived intensity of the force/torque, with the device in a long-term presentation of vibration, are investigated. As a result, the subjects can discriminate the direction within about 40 to 160 ms. In addition, the adaptation of the fingertip force occurred after 35 to 45 s stimulation.