Simultaneous presentation of thermal and tactile sensations using multilateral control under time delay

This paper presents a method of simultaneously presenting tactile and thermal sensations using multilateral teleoperation. Communication using haptic sensation is expected to be a next-generation communication tool replacing telephone or television. A control technique named multilateral control can transmit haptic sensation to multiple points. In this study, robot manipulators are used for tactile sensation presentation, and Peltier devices are used for rendering thermal sensation. A position encoder is used to measure the position of a robot and also estimate the external force, while temperature and heat flow sensors are used for rendering thermal sensation. A routing method to decouple controllers compensates the effect of a time delay between the systems. Defining a modal transformation matrix in a network system eliminates the interference effect of controllers, which is a well-known problem in bilateral and multilateral teleoperation. The matrix shows how to route the information to realize mode-decoupled control in network systems. To consider the motion range of a robot manipulator, the scaling gain is inserted into the modal transformation matrix. The method also compensates the difference between the response speeds of robot manipulators and Peltier devices. This should be considered because the response speed of a Peltier device is slow compared to that of a robot manipulator. The validity of the proposed method is confirmed through experiments.