Incremental Photoelectric Encoder Research Articles

Track Image Acquisition Based on the Signal Device of the Photoelectric Encoder

The photoelectric encoder is a kind of encoder that uses high-precision metrology grating as the detection element to convert the input angular position information into corresponding digital signals through the photo-electric conversion device. It has the advantages of high resolution and wide measuring range, so it is widely used in precision angle measuring devices and high-precision speed regulating systems. In this study, an incremental photoelectric encoder is used, and a receiving system of vertical incidence is chosen, covering a photocell receiving circuit and an infrared circuit. The signal acquisition device of the photoelectric encoder is further designed, that is, the weak photoelectric signal is captured and transformed into an electrical signal that can be recognized by the microprocessor after amplification and adjustment, and then the signal is processed and transmitted. In the test, the signal output of the photoelectric encoder is simulated first. The results reveal that the theoretical output voltage of the drive is 3.5 V, and the peak of the actual output signal is 7.2 V, which meets the design requirements. The designed photoelectric encoder signal device is used with the charge coupled device (CCD) camera to capture the track image. The single-camera and dual-camera tests are carried out respectively. The speed of the bearing vehicle is adjusted to 0.6 m/s~1.2 m/s, and the velocity of the vehicle is adjusted timely. The findings show that the signal device of the photoelectric encoder +CCD camera can be triggered in real-time with the different speeds of the vehicle, and obtain relatively clear images of the track surface and its image of the fastener.

Fully-digital tension control system with PID algorithm for winding ultra-fine enameled wires

An active fully-digital tension control system with PID algorithm is proposed. Only digital signals are involved and processed throughout the closed-loop control system, which employs the micro-controller unit (MCU) dsPIC33EV256GM102 as the main controller with PID algorithm, incremental photoelectric encoder as the angular sensor and AC servo motor as the actuator. A rod-spring mechanism is indispensably constructed to convert the change of tension to the variation of rod’s swing angle. Characteristics of the controlled object are tested and analyzed, from results of which the mathematical model is theoretically deduced. The PID coefficient set is determined by Ziegler and Nichols method. Its practicability is initially validated in simulation using SIMULINK/MATLAB. The prototype is also fabricated and experimented on with ultra-fine enameled wires (0.08mm). In order to enhance the practical performance, PID coefficients are further adjusted in experiments. The results show that the proposed system performs well both in transient process and steady stage. Meanwhile, it has good anti-interference capability as well.

The Design of Motor Precision Positioning System Based on STM32 Single Chip Microcomputer

Aiming at the problem that the positioning accuracy of the motor is not high when the electric hoist vertical lifting industrial material is working, the PC + motion control card + digital AC servo motor positioning cost is too high. The system uses the STM32F103 core controller + incremental photoelectric encoder control scheme, which can locate the position of the material tray accurately. The test results show that the system has the characteristics of high positioning accuracy, stable operation and low cost, The average error is within 0.2mm, it has a certain guiding significance for industrial measurement, automatic control, electrical transmission and other fields of application.

Automatic real-time adjustment of pulse signal of incremental photoelectric encoder

An automatic real-time pulse signal adjustment method for the incremental photoelectric encoder was designed in this study in an effort to ensure highly precise output speed pulse signals. The original moire fringe signal of the photoelectric sensor encoder output is first converted into a voltage signal through the digital potentiometer, then the voltage signal is converted into two orthogonal sinusoidal signals through the amplifier circuit, and finally the sinusoidal signal is subdivided into 10 segments via the subdividing chip and converted into a square wave pulse signal output. The numerical size of the digital potentiometer can be adjusted according to the collected sine signal amplitude value and square wave pulse signal error, which restrains the output error within a reasonable range. Experimental results showed that in high temperature conditions, the system can reduce the peak error of the encoder output square wave signal from 3.12″ to 0.52″; in low temperature conditions, the peak error can be reduced from 4.16″ to 0.56″.

Effect of Encoder Eccentricity on Rolling Speed Control and Elimination Method

Aiming to solve the problems of incremental photoelectric encoder eccentricity in the speed control system of rolling mill, this paper deduces the calculation model of actual speed, and gives a high precision approximation calculation method. Furthermore, the effectiveness and accuracy of the simplified model are verified by the simulation results. The online identification method of eccentricity and initial angle is also given in the paper. In addition, on the basis of continuous model, this article derives from the discrete model of traditional speed measurement scheme based on digital control system. This proposed algorithm has simplicity and excellent application value, and the effectiveness of the algorithm has been verified.

基于空间位置的增量式光电编码器误差检测系统

基于空间位置的增量式光电编码器误差检测系统

Signal acquisition technology for photoelectric encoder based on FPGA

This paper studies the method of signal acquisition for the incremental photoelectric encoder based on FPGA. According to the specification of the photoelectric encoder, corresponding interface circuit is designed. With FPGA as the main control module, the peripheral circuit can work together harmoniously. The simulation analysis shows that results of frequency subdivision and direction discrimination are correct under the control of FPGA (Field Programmable Gate Array). A ZSP3806 photoelectric encoder is used as the sensor to detect the position of mirror scanning mechanism, and experimental result indicates that the angular displacement of measured value is consistent with theoretical requirements.

Rapid detection of index for encoder in rotary inertial navigation system.

This paper presents an approach to detect the index of incremental photoelectric encoder with shorter time for rotary inertial navigation system. The order of index detection and coarse alignment is exchanged in this approach and information from coarse alignment is used to calculate the direction of index. Then two cases of azimuth axis and four cases of horizontal axes are analyzed and corresponding solutions are designed. The paper examines the solutions through two experiments in a tri-axis rotary inertial navigation system, and the results demonstrate that the system can capture index pulse in the application of the presupposes schemes with shorter time.

Design of High Precision Control for Flat Panel System Based on Free Pendulum

The method of dual sensors closed-loop control is designed for the flat panel control system base on free pendulum.With this method, the angle of the free pendulum is detected firstly by adopting incremental photoelectric encoder,and then with the free swing angle as the set-point,the real time rotation angle feedback of the flat panel is detected by the angle sensor to form closed-loop control. The test results shows that this method well accomplishes the detection function,and implements high precise control.

Double Position Loop Design of AC Servo Drive System

The loop controller of double position fully closed makes the AC servo drive system acquire a very high position accuracy and speed following which is hard to be achieved for time-varying parameters, load disturbance, AC motors and severely nonlinear controlled objects. For the system, the dynamic nature can be ensured by the inner position loop adopting PI regulation of half closed loop structure, while the stability and the immunity can be achieved by closed loop structures with the rings outside adopting dual-mode fuzzy control. This article analyzes the cause of positioning errors for servo motor and semi-closed loop structure. The article also explains how to design a two position closed-loop servo system based on fuzzy control by adopting the AC servo motor drive, the motor shaft back-end incremental photoelectric encoder to form the inner position loop and using the motion control card, the inner ring of servo system and the work platform of grating ruler to make up the outer position loop. Based on double position loop composed of three-dimensional laser processing gear, the accuracy of the three-axis linkage workbench position control and the speed following can be ensured, thus meeting the requirement of the laser subsurface engraving machine for high speed and high precision motion.

The Angle Inspection and Control System Based on PLC and Photoelectric Encoder

Aiming at questions of accurate detection of experimental installation’s angle is difficulty like rotating platform, which designs the angle inspection control system adopting incremental photoelectric encoder and PLC. Using gear mechanism and magnified angle pulse of electrical fourfold frequency circuit, switching in biphasic high-speed interfaces of PLC and being displayed on panel calculated by PLC, or achieving to correct the output pulse of motor driving with setting angle value. With experiments testing, the system of inspection and control has advantages of simple construction and angle inspected accuracy of 0.0225°, which satisfying the demands of angle accurate inspection and control of experimental installation.

Un goniomètre original très précis pour la diffraction des rayons X sur poudre à température controlée

A new goniometer for X-ray powder diffractometry and its setting are described. The diffraction angles are easily and quickly measured with high accuracy (10−3°θ), even if experiments require the use of some large or heavy device such as a cryostat or furnace. An original mechanical design allows a direct measurement of the angular position, 20, of the receiving slit, by means of an incremental (10−3°) photoelectric encoder. Three independent stepping motors, for the θ and 2θ scans and the sample translation, allow one to define with a very good reproducibility the `zero' goniometer position. Diagrams of Pb3O4 and Pb(NO3)2 have been recorded in continuous scanning (0.05° θ/min): differences between θ of the two diffraction lines recorded on each side of the goniometer do not exceed ±2 × 10−3°, and reproducibility of measurements is better than +1 × 10−3°. Sensitivity of angular measurements is very good; it is proved by studying, in the range 9–40° (θ), the thermal expansion of Pb(NO3)2 between 273 and 291 K. Moreover, use of a large radius (500 mm) and of a set of undivergent slits improves angular resolution, principally for θ<20°, which is very important for molecular-compound studies: an example is given showing diffraction line splitting due to a monoclinic triclinic phase transition.