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The Peltier is a refrigeration device and usually used in the form of single layer. Sometimes single-layer Peltier may not have sufficient refrigerating capacity with deeper application. To this end, a double-layer Peltier system is proposed in this article. With the increasing layers, the nonlinearity of the system is enhanced and the multiple variables are coupled, bringing about control difficulty. To solve these control problems and promote the disturbance rejection performance, a composite controller is presented, consisting of feedback regulation based on finite-time control and feed-forward compensation based on finite-time disturbance observer. Then, finite-time Lyapunov stability analysis is shown to prove that this control scheme can converge to the equilibrium point in finite time. Last but not least, simulation and experiment are conducted to verify that the proposed strategy has not only a rapid convergence performance but also a prominent disturbance rejection property.

A few experimental studies on thermal tactile perception have shown the influence of the thermal contact resistance which relates to contact surface roughness and pressure. In this paper, the theoretical influence of the skin thickness and the thermal contact resistance is studied on the thermal model describing the temperature evolution in skin and materials when they come in contact. The thermal theoretical profile for reproducing a thermal cue for given contact thermal resistance is also presented. Compared to existing models of thermal simulation, the method proposed here has the advantage that the parameters of skin structure and thermal contact resistance in target temperature profiles can be adjusted in thermal perception simulation according to different skin features or surface roughness if necessary. The experimental results of surface roughness recognition were also presented.

This paper addresses the finite-time tracking problem for the double-layer Peltier system. Peltier is a semiconductor thermoelectrical transform device. It is widely used in the thermal tactile reappearance area. To expand temperature differences, Peltier is usually used in the form of double layers. There are some uncertain factors such as state coupling, external disturbance, and parameter perturbation in double-layer Peltier. Therefore, it is of great theoretical and practical significance to design a controller with superior performance. To this end, a compound continuous integral terminal sliding mode control strategy is proposed here. Firstly, finite-time disturbance observers are designed for feedforward compensation and evaluating the external disturbances. Secondly, the strong robustness of the sliding mode control enhances the disturbance rejection of the system. The continuous integral sliding mode makes the input continuous and weakens the chattering. Also, the terminal sliding mode improves the convergence speed of the system on the sliding surface significantly. The performance of the proposed method is analyzed through Lyapunov stability analysis, simulations, and experiments. Compared to nonsmooth finite-time control, the continuous integral terminal sliding mode control achieves rapid temperature stability and better disturbance rejection under the same condition of finite-time convergence.