Design And Implementation Of Hardware And Software Modules For Prosthetic Fingertip Sensing System

Fingertip sensing system provides the ability to perceive various physical signals,which is of great significance in the fields of medicine and intelligent robots.Prosthetic hands are often used to help the disabled to complete a series of hand movements,during which the fingertip sensing system collects various kinds of tactile information from the interaction between the human-machine interface and the outer world,which is applied to prosthetic hand feedback control,sensory nerve feedback and has effectively promoted the intelligentization process.Therefore,improving the tactile perception ability of prosthetic hands,stably and reliably collecting multi-dimensional sensing signals,and applying them to intelligent prostheses are among the current research hotspots.This paper focuses on the fingertip sensing system of prosthetic hands.First,based on the application scenarios and technical indicators,the overall implementation scheme and criteria are proposed,in which the fingertip sensing system is designed for the acquisition of pressure,sliding /touching and temperature.Based on core modules including elastomer,PVDF piezoelectric film and MLX 90632,the system is developed and verified through theoretical simulation.The hardware system is packaged by combining traditional machinery and casting technology,and along with its mechanical structure and electrical system,it is integrated into a prototype of SJT-7,a set of prosthetic hands.The design and implementation of the hardware system are completed.Second,the signal acquisition software system is developed.According to the structure and application of the hardware system,technical characteristics and basic architecture of the software system are analyzed,while a communication protocol for multi-device collaboration is formulated,including data links and standards.Based on the architecture,software including the Arduino Program,PC Main App,and i OS App is implemented in Arduino/C,Python and Swift,respectively,to realize the analysis,transmission,feedback and visualization of sensing data,which provides support for the calibration and experiments of the fingertip sensing system.Then,a set of calibration test platforms is built to verify the performance of the designed fingertip sensing system,on which the calibration experiments are completed.The input-output characteristics of the fingertip sensing system and the threshold for touching against sliding are determined through pressure calibration and texture characterization experiments,which demonstrates that the fingertip sensing system can recognize the surface characteristics including softness and roughness.Results show that the designed fingertip sensing system meets the design criteria and requirements.Finally,the application of the sensing information collected by the fingertip sensing system to the intelligent design of prosthetic hands is focused.Based on SJT-7,an application strategy combining prosthetic hand control and sensory nerve feedback is proposed,which can produce different vibration stimulus feedback under different pressure and temperature levels,autonomous clutch objects when sliding,and stop grasping objects with abnormal temperatures.A standard experimental process and experimental paradigm are then formulated,under which the application strategy is verified by experiments.Experimental results are analyzed based on various evaluation indicators such as accuracy,correlation,etc.,for which the practicability and feasibility of the sensing system together with the application strategy are verified.The design and application strategy of the prosthetic fingertip sensing system provides support for the performance improvements of intelligent prostheses.