Development Of Automatic Calibration System For Rotary Encoder

As a precision sensor,encoder is the key part of the servo control system to achieve closed-loop control,and its resolution and installation error determine the performance of the servo control system.Before the servo motor leaves the factory,the installation and zero adjustment of the encoder should be completed,so that the mechanical zero point of the servo motor rotor is aligned with the zero position of the encoder.The traditional installation method is to complete the work manually by the manufacturer,which has low installation accuracy and efficiency.In order to realize the high precision and automation of the installation and zero adjustment of the rotary encoder,an automatic calibration system for rotary encoder is proposed and designed in this paper,which includes the function of measuring the accuracy of the encoder.The specific contents are as follows:First of all,this paper analyzes the principle of the accuracy of the encoder detection and installation of zero principle,according to the technical requirements,the overall scheme of the rotary encoder automatic calibration system is designed.Adopting high-precision absolute encoder and stepping motor,the accuracy detection of encoder,the position control of servo motor and the positioning of Z-phase signal of incremental encoder are realized.Adopting high-precision absolute encoder and stepping motor,the accuracy detection of encoder,the position control of servo motor and the positioning of Z-phase signal of incremental encoder are realized.According to the overall scheme of the system,the work flow of accuracy detection and installation of the encoder is designed.Secondly,according to the function division of the automatic calibration system,the hardware and software of the system are designed.Hardware design includes mechanical structure design and parts selection,encoder communication circuit design;The software design includes the lower computer software design and the upper computer system development.The lower computer STM32F429 is responsible for controlling the rotation of stepping motor,data acquisition of encoder and communication with the upper computer;The host computer system is responsible for the instruction sending,data receiving and processing,error calculation and display,error curve drawing,data saving and so on.Finally,the experimental platform of automatic calibration and assembly system is built,the main error sources of the platform are analyzed,and the comparative experiments of encoder accuracy detection and installation zero adjustment are carried out.The experimental results show that the automatic calibration system of rotary encoder can realize the accuracy detection of absolute encoder with 17 bits or less,and the detection time is 5-7 times shorter than that of traditional manual detection;The installation accuracy of the incremental encoder is 3?15?,and that of the absolute encoder is 1?18?.Compared with the traditional manual installation,the time of zero setting is shortened by about 2-3 times;It has the characteristics of high precisio n,high efficiency,convenient operation and high universality.