面向视力障碍群体的仿生电磁触觉传感器设计OA

[Objective]The size and needs of the visually impaired groups cannot be ignored.The application of tactile sensing in the field of assisted reading is particularly noteworthy.This technology can not only be integrated into robots or prosthetic systems,but also provide an effective braille reading tool for blind or visually impaired groups.Therefore,research on vision aids and braille recognition technology with information interaction competency is significantly valuable for offering technical support for visually impaired groups.[Methods]Based on biomimetic principles,the function of biomimetic hair was simulated.With magnetic iron-gallium wire as biomimetic hair and Hall elements as receptors at the hair roots,a biomimetic electromagnetic tactile sensor was designed according to the size of braille dots.Based on magnetization intensity and magnetic induction intensity theories as well as mechanical equations,the relationship curve between the sensor's applied force and output voltage was deduced.A dynamic characteristic testing system was constructed,which consisting of a signal generator,a power amplifier,a vibration exciter,data acquisition card,a computer and a direct current stabilized voltage supply.The dynamic characteristics of the tactile sensor were tested.[Results]Test results show that the tactile sensor can convert applied force into an electrical signal within the range of 0-1.5 N.Within the applied force range of 0-1.5 N,the output voltage gradually increases with higher force.When the contact force is less than 0.5 N,the two approach a linear relationship.The sensor exhibits high stability in output voltage under an applied force of 0.2-1.4 N at a frequency of 1 Hz.Under an applied force of 1.0 N at 1 Hz,its sensitivity is 34.5 mV/N.When the applied force is 0.5 N at 1 Hz,the response time and recovery time are 20 ms and 18 ms,respectively.The designed biomimetic electromagnetic tactile sensor was applied to establish a braille recognition system consisting of a two-finger robotic hand,a motor-driven slide,a data acquisition card,and a computer.The correspondence between braille letters and the output voltage waveform was determined by scanning the braille dots.[Conclusions]The output characteristics of the developed biomimetic electromagnetic tactile sensor were tested.The experimental results show good agreement with the calculated values,indicating that the calculated model can describe the relationship between the applied force and the output voltage.The designed tactile sensor features high stability,high sensitivity,and fast response speed,making it suitable for detecting both static and dynamic applied forces.The braille recognition system was used to determine the voltage waveform corresponded to the braille letters.It is pointed out that voltage waveform peak count,peak intensity,and peak initiation time can serve as the criteria for recognizing the braille letters,demonstrating that the braille recognition system can recognize braille letters.The research results can provide new braille recognition tools and technical pathways for visually impaired groups,allowing for the deep integration of tactile sensors and recognition technology to build assistive technology support systems for visually impaired groups.