Development of Non-Contact Online Measuring System for Middle-Convex and Varying Ellipse Piston

2013 ◽  
Vol 753-755 ◽  
pp. 2282-2285
Author(s):  
Dong Zheng ◽  
Hui Xing Zhou ◽  
Han Wu ◽  
Chao Yang Zhang
Keyword(s):  
Digital Signal Processor ◽  
Digital Signal ◽  
Least Square Method ◽  
High Accuracy ◽  
Measured Data ◽  
Least Square ◽  
Measuring System ◽  
Displacement Sensor ◽  
Contour Error ◽  
Laser Displacement Sensor

A non-contact online measuring system is developed to measure the contour error of the middle-convex and varying ellipse piston. A high accuracy laser displacement sensor is used to measure the elliptical profiles of the piston, and a measuring collector is designed based on digital signal processor (DSP) TMS320F28335 to ensure strict correspondence between the angles and the radii data of the sampling points. The measured data is analyzed with least square method to calculate the contour error of the pistons cross section. The reliability of the measuring system is proved by experiment.

Broadband Spatially Feedforward Active Noise Control Algorithms Using a Comb Filter

2003 ◽  
Vol 125 (1) ◽  
pp. 18-23
Author(s):  
Mingsian R. Bai ◽  
Jienwen Lai
Keyword(s):  
Digital Signal Processor ◽  
Active Noise Control ◽  
Digital Signal ◽  
Least Square Method ◽  
Least Square ◽  
Comb Filter ◽  
Control Algorithms ◽  
Recursive Filter ◽  
Active Noise ◽  
The Ideal

A controller composed of a nonrecursive filter and a recursive filter is used to approximate the ideal controller for a spatially feedforward duct ANC problem. The nonrecursive part represents the dynamics of the transducer, whereas the recursive part is in the form of a comb filter. The parameters of the comb filter are obtained from the impulse response of the controller by using the least-square method. The comb filter is then cascaded with the nonrecursive part implemented as either a fixed filter or an adaptive filter. In the latter approach, two types of LMS-based algorithms are used. The proposed algorithms are implemented on the platform of a digital signal processor. Experimental results showed that the approximated controller attained 17 dB maximal attenuation in the frequency band 200∼600Hz.

Profile Measurement of a Curved Workpiece by the Fuzzy Control of Sensor Positioning

1999 ◽  
Author(s):  
Masatake Shiraishi ◽  
Gongjun Yang
Keyword(s):  
Fuzzy Control ◽  
Control Algorithm ◽  
Experimental Results ◽  
Measuring System ◽  
Displacement Sensor ◽  
Profile Measurement ◽  
Laser Displacement Sensor ◽  
Inclination Angles ◽  
Fuzzy Control Algorithm ◽  
Sensor Positioning

Abstract A laser displacement sensor which has a resolution of 0.5 μm was used to determine the measurement of a curved workpiece profile in turning. This sensor is attached to a specially designed stage and is operated by three motors which are controlled by a fuzzy control algorithm. The experimental results show that the measuring system can be applied to workpieces having inclination angles of up to around 45°. The proposed measuring system has a practical measuring accuracy to within ten micrometers.

Prediction of Comprehensive Thermal Error of a Preloaded Ball Screw on a Gantry Milling Machine

2017 ◽  
Vol 140 (2) ◽  
Author(s):  
Kuo Liu ◽  
Haibo Liu ◽  
Te Li ◽  
Yongqing Wang ◽  
Mingjia Sun ◽  
...  
Keyword(s):  
Thermal Field ◽  
Thermal Characteristics ◽  
Thermal Error ◽  
Least Square Method ◽  
High Accuracy ◽  
Least Square ◽  
Ball Screw ◽  
Milling Machine ◽  
Thermal Fields ◽  
Proposed Model

The conception of the comprehensive thermal error of servo axes is given. Thermal characteristics of a preloaded ball screw on a gantry milling machine is investigated, and the error and temperature data are obtained. The comprehensive thermal error is divided into two parts: thermal expansion error ((TEE) in the stroke range) and thermal drift error ((TDE) of origin). The thermal mechanism and thermal error variation of preloaded ball screw are expounded. Based on the generation, conduction, and convection theory of heat, the thermal field models of screw caused by friction of screw-nut pairs and bearing blocks are derived. The prediction for TEE is presented based on thermal fields of multiheat sources. Besides, the factors influencing TDE are analyzed, and the model of TDE is established based on the least square method. The predicted thermal field of the screw is analyzed. The simulation and experimental results indicate that high accuracy stability can be obtained using the proposed model. Moreover, high accuracy stability can still be achieved even if the moving state of servo axis changes randomly, the screw is preloaded, and the thermal deformation process is complex. Strong robustness of the model is verified.

Ultrasonic Detection Algorithm Research on the Damage Depth of Concrete after Fire

2011 ◽  
Vol 368-373 ◽  
pp. 2229-2234
Author(s):  
Jiang Tao Yu ◽  
Yuan Liu ◽  
Zhou Dao Lu ◽  
Peng Zhao
Keyword(s):  
Ultrasonic Method ◽  
Least Square Method ◽  
Detection Algorithm ◽  
Measured Data ◽  
Structural Member ◽  
Least Square ◽  
Propagation Time ◽  
Practical Application ◽  
Ultrasonic Detection ◽  
Damage Depth

To measure the depth of fire-damaged concrete by ultrasonic method, it was traditionally assumed that the concrete of the fire-damaged structural member could be simply classified into damaged layer and undamaged layer. Based on it, the damage depth can be calculated with a series of single-sided ultrasonic measured data. This method is simple and convenient but less accurate in the practical application. To improve the algorithm, hyperbola curves are adopted to simulate the varying of damage with depth in this paper. And parabolic curves are adopted to simulate the traces of ultrasonic wave in different measured distances. Therefore, the minimum propagation time can be obtained under different damage conditions. Through comparing the calculating results and measured data in different measured distances, the most likely damaged trend can be determined with least square method. At the end of this paper, examples are demonstrated to prove this algorithm feasible and more accurate than the traditional one.

Design of Measuring System for Conical Shell Gluing Platform and Analysis of Factors Influencing Measurement

2017 ◽  
Vol 872 ◽  
pp. 373-377
Author(s):  
Li Chao Liu ◽  
Xiang Long Zhu ◽  
Zhi Gang Dong ◽  
Ren Ke Kang
Keyword(s):  
Data Acquisition ◽  
Cross Sections ◽  
Conical Shell ◽  
Incident Angle ◽  
Measuring Method ◽  
Measuring System ◽  
Displacement Sensor ◽  
Laser Displacement Sensor ◽  
Before And After ◽  
Open Cnc System

As a cover to prevent the inside system from being destroyed, conical shell is widely used in national defense and meteorological fields. Radial runouts at specific cross sections of conical shell need to be measured before and after gluing for coaxiality requirement between conical shell and connecting ring. So a measuring system of vertical gluing platform was designed. Noncontact laser displacement sensor was adopted in the measuring system for advantages of quick data acquisition, high measuring accuracy and no surface scratch. Compared with traditional measuring method by a dial indicator, laser displacement sensor is more appropriate to carry out the measurement on the surface of conical shell. An open CNC system was developed for the measurement. It was based on industry personal computer (IPC) which and took motion control board and data acquisition board as its core. Experiments were conducted on the designed measuring system to find out the factors which influence measuring results. Measuring data showed that measuring results appeared to be a parabolic distribution in the working range of the sensor and the symmetry axis of the parabola was at the middle position. The variation of incident angle has no obvious influence on measuring results.

The Circle-End-Face Centering Device Based on Image Processing

2014 ◽  
Vol 926-930 ◽  
pp. 3447-3450
Author(s):  
Yong Bo Li ◽  
Yun Zhao Xu ◽  
Jia He
Keyword(s):  
Image Processing ◽  
Digital Image Processing ◽  
High Stability ◽  
Least Square Method ◽  
High Accuracy ◽  
Concentric Circle ◽  
Least Square ◽  
Programmable Logic ◽  
Edge Extraction ◽  
Stability And Accuracy

The circle-end-face centering device which is in the base of image processing accomplishes the center of the cylinders end face by digital image processing. Through edge extraction and doing the matching in the calculation of the least square method, the coordinate of the central of the circle can be calculated. At last, the drill will be moved to the central of the circle and do the punching by the actuator. This equipment is in the high accuracy and speed compared with the traditional way and the concentric circle laser of marking with the center. Meanwhile, the actuator consists of the programmable logic controller, touch panel and servo drivers which is in the high stability and accuracy. Certainly it is easy to be controlled by the method.

Subpixel Edge Detection Algorithm of the Glass Bottle Based on Zernike Moments

2011 ◽  
Vol 80-81 ◽  
pp. 1345-1349
Author(s):  
Hao Yang ◽  
Lei Pei
Keyword(s):  
Edge Detection ◽  
Fast Algorithm ◽  
Least Square Method ◽  
Threshold Value ◽  
Detection Algorithm ◽  
Zernike Moments ◽  
Least Square ◽  
Measuring System ◽  
Zernike Moment ◽  
Glass Bottle

The accuracy of edge detection determines the accuracy of actual dimension measurement，in order to improve the measuring accuracy, this paper proposes a fast algorithm of detecting the glass bottle dimension based on Zernike moments. Firstly, combines the traditional Zernike moment-based method with Otsu adaptive threshold algorithm and a new fast algorithm for edge detection is proposed. Then uses this fast algorithm to detect the edge of glass bottle with subpixel-level and uses the least square method to fit ellipses formed by the glass bottle mouth and bottom. Calibrated the system with standard gauge block and obtain the actual dimension at last. Experimental results show that the improved algorithm not only can make the edge detection reach the subpixel-level accuracy, but also can avoid the edge misidentification and inefficient causing by repeatedly manual adjustments to select the threshold value when detecting the edge. Making a rapid, accurate, non-contact measuring system becomes a reality.

Error Calibration System for Time Grating Angular Displacement Sensor

2013 ◽  
Vol 662 ◽  
pp. 705-708
Author(s):  
Zhong Hua Gao
Keyword(s):  
Angular Displacement ◽  
Least Square Method ◽  
Least Square ◽  
Displacement Sensor ◽  
Calibration System ◽  
Displacement Sensors ◽  
Optical Grating ◽  
Calibration Algorithm ◽  
Error Calibration ◽  
Angular Displacements

A calibration system was developed for time grating angular displacement sensors to calibrate errors of this type of sensor. In the system, the motor was controlled by ARM processor according to the setting value coming from the USB port of the computer, and therefore the motor outputted angular displacement values. Meanwhile, with the motor turning, the optical grating, which was used as the criterion instrument, and time grating turned together corresponding angular displacements. Several displacement values from a circle of sensors of time grating and optical grating were sent to computer by serial port to be processed. Furthermore, an error calibration algorithm, which was based on the least square method (LMS), was used in this calibration system. The precise of time grating can reach to ±0.7″after calibrating using this algorithm and the process of error calibration can be automatically made by the computer.

A three-dimensional measuring system based on 2D laser displacement sensor

2014 ◽  
Author(s):  
Sulun Jiang ◽  
Yuegang Fu ◽  
Wangbin Zhu ◽  
Yingwei Zhang ◽  
Weichen Wang
Keyword(s):  
Three Dimensional ◽  
Measuring System ◽  
Displacement Sensor ◽  
Laser Displacement Sensor

Research of Quantitative Analyzer for Fluorescence Immune Chromatography Strips

2013 ◽  
Vol 373-375 ◽  
pp. 1000-1006
Author(s):  
Xiao Ting Li ◽  
Kai Jiang ◽  
Ping Wang
Keyword(s):  
Least Square Method ◽  
High Accuracy ◽  
Least Square ◽  
Good Prospect ◽  
Fluorescence Immunoassay ◽  
Response Characteristics ◽  
Photoelectric Detection ◽  
Detection Technology ◽  
Relative Standard ◽  
Low Pass

Fluorescence immunoassay technology is widely recognized as the most sensitive detection technology, now widely used in clinical testing. The research of quantitative analyzer for fluorescence immune chromatography strips is of great significance. In this thesis, a quantitative analyzer for fluorescence immune chromatography strips has realized, based on photoelectric detection principle and immunochromatographic. The system uses LPC1788 and MSP430 as processors. Using some algorithms such as low-pass filtering, least square method and area method to analyze the detected waveform and eliminate noise with high accuracy. In our experiment, the minimum detection concentration is at several mIU/ml levels, the relative standard deviation is less than 2% and it has good linear response characteristics in a concentration range from 0.5125 to 952mIU/ml while the correlation coefficient R2 is 0.981. The instrument has a good prospect.

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