Design And Testing Research Of Photoelectric Force Sensor System

The principle of photoelectric force sensor is changing the force value into optical signal, then changing the optical signal into electrical signals based on the photoelectric effect of photoelectric devices. This kind of sensors has unique and important application value and many other advantages, such as noncontact, high reflection speed, high sensitivity, immunity to electromagnetic interference, small volume, low weight, low cost and so on, comparing with piezoelectric force sensor and strain gauge sensor widely used on the market.This paper designed a new kind of photoelectric sensor based on photoelectric effect of photodiode, analyzed its principle, tested the photoelectric displacement characteristics of photodiode, studied and designed a kind of elastic body structure, established the kinematics model of elastic body of this sensor and analysed the relationship of deformation of elastic body and the structural parameters and bearing capacity value based on flexibility matrix method and pseudo rigid body model method, verified the theoretical analysis model and studied relationship of the elastic thermal strain, frequency and strain, combining with the finite element method, summarized the law of elastic body affected by temperature change,30resonant elastic body frequency and the effective bandwidth based on elastic simulation.This paper developed a sensor system, including a hardware system and software system, satisfying requirements of high speed, high sensitivity and friendliness. The system takes STM32microprocessor as the core, and signal amplification circuit, A/D conversion circuit, temperature sensor circuit, communication interface circuit, E2PROM circuit as the main module, finishing the hardware system development, uses voltage decoupling, grounding technology and digital filtering technology to improve the anti-jamming ability of sensor hardware system, reflect and record the design requirements of data sampling timely based on the friendly software system, design the PC system by using Labview. The sensor system platform based on photoelectric force sensor tested the sensor. The static calibration of sensor prototype shows that the sensitivity of the sensor is0.0778mV/g and the delaying is0.061%,that the repeatability is0.319%and the. linearity is0.1125%, that the overall accuracy is up to0.1735%. the sensor with high precision and sensitivity, and has good dynamic performance, and has popularization and application value. Using the least squares curve fitting method to conduct nonlinear error compensation in sensor system, compensation method is practical, feasible, and obviously effective, the compensation after the maximum error value is|emax|=0.797g, which is improved compared with previous compensation|emax|=8.151g, Sensor temperature error compensation method is discussed in this paper, concrete steps combined with the least squares curve fitting method for this kind of temperature error compensation method circuit which can be effectively used in this sensor system are put forward as well.Based on one-dimensional photoelectric force sensor design method, this paper discusses and analyzes two-dimensional photoelectric force sensor, A kind of elastomer structure design which can eliminate dimensional coupling is discussed, Using the method of flexibility matrix method and the pseudo rigid body model, kinematics analysis is carried out on the elastomer, combining with the finite element method, elastomer dimensional coupling error can be obtained after simulation by validation for elastomer theory motion model.