The absolute positioning accuracy of a robot is an important specification that determines its performance, but it affected by several error sources. Typical calibration methods only consider kinematic errors and neglect complex non-kinematic errors, thus limiting the accuracy. To further improve accuracy, we propose artificial neural network optimized differential evolution algorithm. Specifically, structure parameters are iteratively updated to both efficiency. Then, deviation caused...

Digital projectors are used as standard parts at present in fringe projection profilometry systems to project structured-light patterns onto the object surface be measured, and distortion of projector lens must calibrated compensated accurately satisfy accuracy requirement industrial applications. A novel method is proposed determine pixel coordinates marker points a calibration target terms projective transform. With method, can with sub-pixel level. The applicable for chessboard pattern or...

In this article, a method of error source analysis and detection to improve the angle measurement accuracy rotary encoders in precision measuring instruments is proposed. The caused by installation eccentricity grating disk radial motion rotating shaft analyzed, model built. introduced, visual system image processing technology proposed detect eccentricity. verification experiment use an autocollimator polygon carried out. residual after comparison within ±6″ accounts for 9% error. verified,...

Abstract The method based on broad spectrum interference using femtosecond pulses is an important ranging method. In this paper, we experimentally evaluate the effect of interferometric spectral bandwidth used for calculation results, and precision can be improved by choosing optimal bandwidth. addition, in order to eliminate influence fluctuations measurement introduce detrend algorithm into processing compare results before after improvement. Then, four kinds nominal distance were measured...

China has the world's largest elderly population and an increasing number of empty-nest elderly. The purpose this study is to evaluate effectiveness Self-Mutual-Group model on social support elderly, thus providing reference for improving their quality life.A intervention was conducted between October 2016 May 2017 at six communities in Taiyuan, Shanxi Province, China. A total 350 aged 60-88 years were randomly assigned group (n = 167) with a 7-month SMG-based or control 183) no...

China has the world's largest size of elderly population. Mental disorders elders deserve keen attention. This study aims to comparatively explore mental and risk factors among empty non-empty nesters. Using stratified random cluster sampling method, we recruited 8526 aged 60 years above from 11 cities in Shanxi Province central China, comprising 4901 3625 The were assessed with 12-item Chinese Health Questionnaire (CHQ-12). binary logistic regression was performed analyze two groups....

The measurement accuracy of the precision instruments that contain rotation joints is influenced significantly by rotary encoders are installed in joints. Apart from imperfect manufacturing and installation encoder, variations ambient temperature could cause angle error encoder. According to characteristics 2π periodicity at stationary complexity effects changes, method based on Fourier expansion-back propagation (BP) neural network optimized genetic algorithm (FE-GABPNN) proposed improve...

In this paper, a 3D artifact is proposed to calibrate the kinematic parameters of articulated arm coordinate measuring machines (AACMMs). The composed 14 reference points with three different heights, which provides 91 lengths, and method laser tracker multi-stations. Therefore, an AACMM can be calibrated in one setup artifact, instead having adjust 1D or 2D artifacts positions orientations existing methods. As result, it saves time comparison traditional artifacts. performance verified...

The laser scanning measurement system has a pivotal role in precision thanks to the non-contacting and low-cost advantages, but traditional methods systems are inadequate terms of accuracy, efficiency, adaptability. In this study, an efficient 3D based on asymmetric trinocular vision multi-line is developed improve performance. design, working principle, reconstruction method explored, as well innovation system. Furthermore, fringes indexing presented K-means ++ clustering hierarchical...

Abstract In this paper, a new kinematic parameter error calibration method based on the Levenberg–Marquard and beetle antennae search algorithm is proposed to enhance positioning accuracy of industrial robot. Firstly, Modified Denavit–Hartenberg model chosen establish for Secondly, errors are calibrated by then obtain Thirdly, these taken as center values initial individual algorithm. The accurately using best value errors. Finally, experimental verification results demonstrate that robot...

Portable articulated coordinate measuring machine (PACMM) is a kind of high accuracy measurement instrument and it has been widely applied in manufacturing assembly. A number key problems should be taken into consideration to achieve the required accuracy, such as structural design, mathematical model calibration method. Although classical kinematic PACMM Denavit-Hartenberg (D-H) model, representation D-H encounters badly-conditioned problem when consecutive joint axes are parallel or nearly...

This paper presents a novel impact rotary motor based on piezoelectric tube actuator with helical interdigitated electrodes which has compact structure and high resolution. The assembled prototype maximum diameter of 15 mm length 65 works under saw-shaped driving voltage. LuGre friction model is adopted to analyze the motion process in dynamic simulations. From experimental tests, first torsional resonant frequency 59.289 kHz free boundary condition. A series experiments about stepping...

Line laser scanning measurement is a major area of interest within the field 3D measurement. Traditionally, sub-pixel extraction stripes dominant point for line In particular, noise separation stripe images and accuracy feature are main challenges in complex circumstances. To this end, study utilizes robust accurate method with two steps to extract features Laser segmentation based on deep semantic network initially implemented elimination images. Then, gray peak points accomplished by...

A novel impact two-degree-of-freedom (2-DOF) motor based on the decomposed screw-type motion of a piezoelectric actuator (PA) has been proposed. The fabricated prototype maximum diameter 15 mm and length 100 which can produce torsional angle about 1000 μrad longitudinal displacement 1.03 μm under saw-shaped driving voltage with 720 Vp-p (peak-to-peak voltage). When axial prepressure generated by spring is 1N radial snap ring 14 N, realizes rotary frequency from 200 Hz to 4 kHz. 11.7 N 21.1...

Objectives This study aimed to investigate anxiety status and its relationship with body mass index (BMI) among empty nesters in China, so as improve their quality of life provide direction for further research. Methods A cross‐sectional survey was conducted 4901 Shanxi, China. Anxiety, weight, height, depression, socio‐demographic variables, attention daily nutritional health, social activities, self‐care ability were evaluated the study. T‐tests chi‐square tests used compare differences...

In order to obtain accurate position of the inner key components in experimental advanced superconducting tokamak (EAST), a combined optical measurement method which is comprised laser tracker (LT) and articulated coordinate measuring machine (CMM) has been brought forward. LT, an instrument large range high accuracy, employed for establishing precision network EAST, CMM also EAST. The uncertainty analyzed by Unified Spatial Metrology Network (USMN) 0.20 mm at confidence probability 95.44%....

To help readers around the world comprehensively understand development of journal and evolution cooperation study, we employed a bibliometrics analysis for Journal American College Health. One-thousand-one-hundred-forty-three articles published in this from 1994 were analyzed using visualization software CiteSpace. The annual number cited studies increased. by RP Keeling H Wechsler at forefront. "College student" "alcohol" prevalent keywords. University Wisconsin Harvard institutional...

Abstract To solve the measurement problems of inner shape large-scale workpieces, such as excavators with movable arms, this paper proposes an method based on circular structured light. First, center laser stripe is extracted a modified Steger method. Second, multi-diameter concentric calibration gauge design used to calibrate optical plane proposed system and address problem deviation motion error in 1D linear stage traditional process. Finally, experiments are conducted. The corresponding...

Multi-camera laser scanning measurement is emerging as a pivotal element in three-dimensional (3D) optical measurements. It reduces occlusion and enables the gathering of more 3D data. However, it also increases difficulty system algorithms obtaining high accuracy. To improve accuracy, there an urgent need to address global calibration error correction issues caused by employment multi-view systems. An accuracy improvement method for measurements based on point cloud optimization then...

As an important international journal in the field of school health, Journal School Health has drawn wide attention from researchers and readers around world. Therefore, it is to conduct a systematic retrospective study journal. With aim understanding development evolutionary process cooperative this comprehensively, we employed bibliometric analysis using articles published 1965. Using bibliometrics, 5242 were extracted then analyzed visualization software CiteSpace III. The annual amount...