Design, analysis and experimental validation of an ungrounded haptic interface using a piezoelectric actuator

In this paper, a novel small ungrounded haptic device for spatial guidance is presented. The device uses a piezoelectric actuator to generate the haptic illusion of an external force. Using asymmetric accelerations, the device is thus able to generate a pulling or pushing sensation to a user. A dynamic model of the device is developed, which allows the determination of the optimal parameters to be used. These parameters are the frequency of the input signal and the natural frequency of the device including the connection with the user handle. It is shown that by using a particular input frequency, depending on the natural frequency of the device, the acceleration of the moving mass and its asymmetry are both maximized. Experimental tests show that the device is able to generate a haptic perception in two opposite directions with a success rate ranging from 80% to 86%.