Research On Display Of Thermal Tactile Under Virtual Environment Based On Double Peltiers

The purpose of virtual reality technology is to provide people with the sense of reality and immersion, which needs to reproduce the five senses of human (hearing, sight, taste, smell and touch) effectively. Tactile mainly includes force tactile, texture tactile and thermal tactile. In the past, there was little research on thermal tactile, but with the development of virtual reality technology, people are paying more attention to the research and application of thermal tactile.Thermal tactile displays have been developed to present thermal cues to the hand to facilitate object recognition in virtual environments or in teleoperated robotic systems. This paper focuses on this application domain of thermal tactile displays, replaces single peltier with double peltiers, establishes two order model of temperature, and uses state space equation and observer to reproduce the thermal interaction between an object and the hand as they make contact. Firstly, an overview of thermal perception and the mechanisms underlying the processing of thermal information is provided to give a framework for analyzing the design of thermal tactile displays. Secondly, the models developed to reproduce thermal tactile are analyzed with the consideration of various factors influencing heat transfer, and the algorithms of temperature control and anti-disturbance control are given. The author uses such a device to reproduce various thermal changes when the finger touches different materials. Finally, the author performs a series of thermal tactile sensing experiments based on the physiological characteristics of the skin, which is the foundation for the application of thermal tactile information.The device chooses OMAP-L138 produced by TI to be core controller. This chip consists of ARM9-AM1808 and DSP-C6748 and the main frequency is 456MHz. ARM runs Linux operating system and is responsible for non real-time tasks. DSP runs SYS/BIOS operating system and is responsible for real-time tasks. The dual core systems communicate with each other via DSPLINK. The control methods include traditional PI control; GPI control based on state observer; and bilateral GPI control. Compared with single peltier system, double peltiers system has better heating and cooling rate and the ability of anti-disturbance. As a result, it can better reproduce thermal tactile.