Comparison of people's responses to real and virtual handshakes within a virtual environment.

In this paper we present a method for evaluating a haptic device which simulates human handshakes interfaced via a metal rod. We provide an overview of the haptic demonstrator and the control algorithm used for delivering realistic handshakes. For the evaluation of this handshake demonstrator we introduce a 'ground truth' approach, where we compare the robot handshakes with handshakes operated by a human via the same metal rod. For this, an experiment was carried out where the participants entered a virtual environment, i.e. a virtual cocktail party, and were asked to perform a number of handshakes, either with the robot operating with one of two control algorithms operating the metal rod - a basic one for comparison or the proposed new advanced one, or with a human operating the metal rod. The virtual environment was represented only through audio and haptics, without any visual representation, i.e. the subjects participated blindfolded. The evaluation of each handshake was achieved through the subjective scoring of each of the handshakes. The results of the study show that the demonstrator operating with the proposed new control scheme was evaluated significantly more human-like than with the demonstrator operating with the basic algorithm, and also that the real human handshake was evaluated more like a real human handshake than both types of robot handshakes. Although the difference between the advanced robot and human handshake was significant, the effect sizes are not very different, indicating substantial confusion of participants between the advanced robot and human operated handshakes.