Research On High Density And Large Area Tactile Display With Self-latching

At present,there are 285 million visually impaired people in the world,including about 39 million blind people,and the number of blinds is still growing.With the development of the information age,the blind people have a great demand for information reading.However,the disadvantages of traditional braille books,such as heavy,easy to lose and less content,are gradually obvious.The single-line Braille display on the market shows that the Braille characters are limited,which is not as good as full-page braille books.In order to solve the problem of blind reading difficulties,this paper proposes an electromagnetic tactile display with permanent magnet self-latching,which can display Braille characters,graphics,formulas and other contents.It has the characteristics of small size,low power consumption and fast response speed,which can better meet the use requirement of the blind.Aiming at the high density of dot matrix,fast response,low power consumption and portability,a micro-actuator was designed by means of electromagnetic drive and permanent magnet self-latching,and the development of tactile display was realized through the assembly of 100 actuators.In the paper,all parts design and modeling,material selection and parts processing were completed.Combined with the problems in the actual assembly,further structural improvement was proposed for the tactile display..The working principle and internal structure of the self-latching actuator were described in detail.Based on the pressure threshold of finger touch,the magnetic field analysis of the cylindrical permanent magnet was used to determine the force of permanent magnet on magnetic material and the corresponding air gap,and then the relevant parameters of the coil in this paper were calculated.According to the preliminary calculated structural parameters,the electromagnetic force and the magnetic force was calculated by using Ansoft Maxwell building model and static simulation analysis under different current conditions of the coil.And the relative position of the permanent magnet and the coil,the thickness of the permanent magnet and wall thickness of coil framework was optimized.In the dynamic simulation analysis,the displacement,magnetic force,velocity curve of the permanent magnet during the up and down motion,and the dynamic response time of the two motion were obtained.Finally,relevant performance tests were carried out on the prototype of tactile display in this paper,including Braille dot response power-on time,holding force and touch perception experiment,in which holding force of Braille dot is about 48mN and Braille dot response power-on time is 2ms.The experimental results were basically consistent with the simulation conclusion,and the feasibility of the device was verified.