Study On Probe Pre-travel Error In Contact Measurement On Curved Surface

Precision measurement is an effective method for evaluation of processtechnology, the development of measuring technology is the basis and prerequisite ofmanufacturing industry. CMM has the capability of high precision measurement, butthe parts are measured by other equipment and this will reduce the accuracy and delaythe process circle. The modern industry has proposed more and more strictrequirement in parts’ precision, therefore the demand of on-machine verification isproposed. The on-machine measuring system combines the processing function ofnumerical control at CNC and the quality verification function of coordinatemeasurement devices to enable CNC to verify the quality of the workpiece.This paper was going to do the research mainly focusing on the followingaspects:(1)Study the structure and Working principle of probe,study working principle ofthe trigger type probe to prepare a theoretical basis for the study of pre-travelmeasurement error for subsequent research.(2)Research the source and compensating method of errors, make stress analysisbased on the working principle of trigger type probe that lead to the main source oferror. Focusing on the pre-travel measurement error which is the most influencefactors and established the mathematical model.(3)Neural network method is proposed according to nonlinear system modeling,set up a prediction model based on radial basis function artificial neural networkmethod, and established specific steps. Established a pretravel measurement errorprediction model based on the neural network. With the help of Matlab neuralnetwork toolbox, train and test the RBF neural network, BP neural network and a newcompound neural network.(4) Testify the precision,reliable and trustworthy was implemented byexperiment.