Design And Implementation Of Thermal Haptic Reconstruction System For Virtual Experiment

With the development of virtual reality technology,virtual experiment teaching is gradually entering the education system of various subjects.Virtual experiment can improve or solve the existing problems of high cost of equipment,shortage of raw materials and high risk in traditional experiment.The sense of reality of virtual experiment is determined by multiple channels of vision,hearing,touch and smell.As the main channel of human skin perception,haptic can improve the sense of immersion in virtual experiment and promote virtual experiment teaching.In the basic experiments of middle school,the haptic sensation is mainly generated by thermal haptic sensation,which is presented in a variety of ways.However,currently,there is a lack of equipment in the market that can provide multiple modes of thermal haptic sensation reconstruction in the virtual experiment,and the temperature change is mainly solved by visual compensation in the field of virtual simulation.In view of the above situation,a thermal haptic sensation reconstruction system is designed and realized.The system is composed of two devices,a desktop thermal sensation device and a thermal sensation haptic glove,which can provide local or global,contact or non-contact thermal haptic sensation reconstruction for different scenes of the virtual experiment.The main research contents of this dissertation are as follows:(1)A desktop thermal sensation device based on the heat haptic reconstruction of PTC heater is proposed and realized.The device has four degrees of freedom of heat source location,so that the thermal sensing position generated in the experiment is more accurate.The PID control algorithm is used to control the temperature of the hot air generated by the PTC heating plate in closed loop,which improves the accuracy of temperature reconstruction.Then,the temperature of the air outlet of the device is collected and analyzed,and the corresponding relationship model is obtained to provide a theoretical basis for the temperature control of the device.The interactive control method between human and device is also designed and analyzed,which provides a reference for the use of the device.(2)A thermal sensation haptic glove based on semiconductor refrigeration chip and carbon fiber heating chip is proposed and realized.The glove can produce heat and cold perception in 12 parts of the hand,and separate control of cooling and heating,which can be applied to a variety of temperature reconstruction scenes.Through the relationship model of voltage and temperature rating,the method of open loop control of hand skin temperature rating is realized,and the interactive control between human and gloves is also designed and analyzed.(3)A wireless communication protocol using Mesh bluetooth networking is designed and implemented.The Mesh network connects the PC terminal,the desktop thermal sensation device and thermal sensation haptic glove as a whole.The two devices can communicate with each other without passing through the PC.The communication protocol designed separately includes the process of encoding and decoding,which makes the data transmission and control more convenient.(4)Two temperature discrimination experiments and two virtual experimental cases were designed.The discriminant experiments tests the human body's perception of temperature,and the virtual experimental cases were used to test the thermal haptic feedback and the cold haptic feedback of the two devices of the system respectively.The experimental results show that the system was effective in generating thermal haptic feedback and could enhance the immersion of the virtual experiment.