Design And Development Of Data Acquisition System For Flexible Sensor Array

The variety of sensing units integrated with smart skins and e-skin is increasing,and the scale of sensors is increasing.The superior performance of smart skin or e-skin applications is not only reflected in flexible sensing components,but also largely depends on the reliability of data acquisition.The crosstalk problem of sensor array,signal processing problems,and the contradiction between acquisition speed,accuracy and scale have always restricted the expansion of sensor array's applications.Therefore,it is essential to build a data acquisition system that is suitable for various types of sensors to realize the wide application of large-scale sensors in smart skin and e-skin.This paper mainly focuses on the design and development of data acquisition systems for commonly used flexible pressure sensor arrays.1)A detailed analysis of the principle problems encountered in the development of data acquisition systems,including the principle of crosstalk of capacitive sensor arrays,the contradiction between the weak signal and transmission of piezoelectric sensors,and the phase matching problem caused by multiplexing switching.Using the multiplexer and the counting chip to achieve time-sharing scanning that matches the multiplexing principle of the sensor array.A charge amplification circuit is designed for the weak signal of the piezoelectric sensor to solve the problem under long-distance transmission.In order to solve the problem that capacitive sensor belongs to high precision micro-capacitance signal in smart skin and e-skin application scenario,a capacitance detection system based on CDC chip PCap01 AD is proposed.In order to solve the crosstalk problem of capacitive sensor array,a controllable single-pole double-throw switch is used in time-sharing scanning circuit to shield the crosstalk signal to the ground,which realizes the array acquisition and solves the crosstalk problem at the same time.The system has good stability,wide measurement range and high accuracy.2)A data acquisition software system for flexible pressure sensor arrays was developed.Matching the design principle of the hardware circuit,the lower computer module of data acquisition is built with STM32F103 as the core,and the virtual instrument based on LabVIEW is developed to realize real-time data transmission,display and storage.Based on the existing equipment and resources,the experimental data was tested on the data acquisition system of the flexible sensor array.The feasibility of the acquisition system in distributed stress testing was verified by analysis.