Study Of Signal Collection And Horizontal Scanning System Of Stylus-type Micro-displacement Sensor

With the increasing requirement on mechanical parts’ dimensional accuracy, precise manufacturing and precision measurement are becoming more and more important. It plays a significant role on the industrial level of the whole country. Among them, roughness profiler is an important part in precision measurement. However, the technology of roughness profilers in China is not as advanced as foreign countries. Thus, designing a roughness measuring instrument with high precision and high reliability has important practical significance.This study mainly focuses on the early research on the horizontal scanning system, stylus-type constant control systems and the collecting system of stylus-type micro-displacement sensor. We analyze various technical solutions on horizontal scanning system, and determine to drag scanning program block by using timing belt based on the seismic requirements. We also analyze the possible crawling during scanning process, and design the baseline rod using steel as material, as well as the friction using copper alloya as friction plate. As for the probe constant control system, we develop drive for the constant voice coil motor. Among them, using 12 DAC providing a weak variable voltage and emitter follower to follow in isolation, and amplify current to drive the load by the Darlington. With respect to and the collecting system of stylus-type micro-displacement sensor, we mainly use the grating angle sensors, data acquisition card and PC to form the acquisition system. The PC sends commands to the acquisition card based on the communication protocol, receive and process the returned value from the capturing card, and display on the PC software.Finally, we build experimental platform to verify the feasibility of the experimental system, including the horizontal scanning system, stylus-type constant control systems and the collecting system of stylus-type micro-displacement sensor. Based on the stylus angle signal lever measured by the grating angle sensor, the constant control of the stylus converts it to the changing current value of voice coil motor. Then the changing current value of voice coil motor is transferred to voice coil motor through the constant drive. Thus, we could achieve a constant measuring force of the stylus. By measuring the profile of the optical Fresnel lens and comparative experiments, it could be verified that the horizontal scanning system and collection system could collect the outline data of the sample correctly.