Journal articles: 'Position Error'

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TALLANT, JONATHAN. "An Error in Temporal Error Theory." Journal of the American Philosophical Association 4, no. 1 (2018): 14–32. http://dx.doi.org/10.1017/apa.2018.5.

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AbstractWithin the philosophy of time there has been a growing interest in positions that deny the reality of time. Those positions, whether motivated by arguments from physics or metaphysics, have a shared conclusion: time is not real. What has not been made clear, however, is exactly what it entails to deny the reality of time. Time is unreal, sure. But what does that mean?There has (within the recent literature) been only one sustained attempt to spell out what it would mean to endorse a (so-called) temporal error theory, a theory that denies the reality of time: Baron and Miller's (2015) ‘What Is Temporal Error Theory?’ Despite the fact that their paper makes significant strides in spelling out what would be required, my claim in this paper is that their position must be rejected and replaced. In addition to rejecting Baron and Miller's position, I also offer that replacement.

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Chen, Dong Ju, Yong Zhang, Fei Hu Zhang, and H. M. Wang. "Emulating and Modeling for Position Errors of Ultra-Precision Aspherical Grinding." Applied Mechanics and Materials 10-12 (December 2007): 291–96. http://dx.doi.org/10.4028/www.scientific.net/amm.10-12.291.

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In the process of the ultra-precision grinding, the machining path of the aspherical is the result of motor coordination by several axes for the numerical control system. Since the motion of each axis have errors, there are big errors between the real positions and the theoretical positions, and the position error of the wheel infects the accuracy of the workpiece greatly. This paper analyses the position error property of the wheel and finds the machining approach path has nothing to do with the position error, just do with to the present machining point. In order to solve the problem, the method using the Neural Network optimized by the Genetic Algorithm to establish the position error model is introduced. A three-layer error back propagation (simplified as BP) Neural Network is used to establish the position error model, the position coordinates (x, z) of the program instruction is input layer, and the corroding measured error value ( Δx , Δz ) is output layer. Before training data sample, using the Genetic Algorithm to optimize the Neural Network to improve the predicting accuracy of the Neural Network, and reduce the training time. The emulation results indicate that using the Neural Network model optimized by the Genetic Algorithm can predict the position error in a high degree of accuracy, and at the same time, according to the predicting results, compensating the position error of the wheel is possible.

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Zhang, Xiu Heng, Peng Ba, and Li Mu. "Position Error Sensitivity Analysis for Polishing Robot." Advanced Materials Research 500 (April 2012): 326–30. http://dx.doi.org/10.4028/www.scientific.net/amr.500.326.

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t is the goal of this paper to describe an error analysis methodology for polishing robot on a manufacturing floor. With the generalized errors considered in the model, the end-effector position and orientation errors are calculated as a function of the generalized error. The analysis is to determine which physical errors significantly influence the end-effector error. The method and computer program have been applied to the performance evaluation of a robotic manipulator to be used in a polishing robot. This methodology can be applied to estimate calibration error and give the severity value to help the designer to select the polishing robot parameters.

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He, Ruibo, Xiwen Li, Tielin Shi, Bo Wu, Yingjun Zhao, Fenglin Han, Shunian Yang, Shuhong Huang, and Shuzi Yang. "A kinematic calibration method based on the product of exponentials formula for serial robot using position measurements." Robotica 33, no. 6 (April 1, 2014): 1295–313. http://dx.doi.org/10.1017/s026357471400071x.

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SUMMARYBased on product of exponentials (POE) formula, three explicit error models are given in this paper for kinematic calibration of serial robot through measuring its end-effector positions. To obtain these error models, the tool frame should be chosen as reference frame at first, and then each position–error-related segment in the error models using pose measurement should be selected. And during kinematic parameter identification, all the errors in joint twists are identifiable, and the initial transformation errors and the joint zero-position errors can be identified conditionally. Namely, the initial transformation errors are identifiable if they do not contain orientation errors. And the joint zero-position errors are identifiable when a robot only consists of prismatic joints and the coordinates of its joint twists are linearly independent.The effectiveness of this calibration method has been validated by simulations and experiments. The results show that: (1) the identification algorithms are robust and practical. (2) The method of position measurement is superior to that of pose measurement.

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Lee, Jae Hong, Hojin Ju, and Chan Gook Park. "Error Analysis of PDR System Using Dual Foot-mounted IMU." E3S Web of Conferences 94 (2019): 02007. http://dx.doi.org/10.1051/e3sconf/20199402007.

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In this paper, we analyze the position errors of the pedestrian dead reckoning (PDR) system using foot-mounted IMU attached to each foot, and implement PDR system using dual foot-mounted IMU to reduce the analyzed error. The PDR system using foot-mounted IMU is generally based on an inertial navigation system (INS). To reduce bias and white noise errors, INS is combined with zero velocity update (ZUPT), which assumes that the pedestrian shoe velocity is zero at the stance phase. Although ZUPT could compensate the velocity and position, the heading drift still occurs. When analyzing the characteristics of the position error, the error shows a symmetrical characteristic. In order to reduce this error, the previous researches compensate for both positions by applying feet position constraints. The algorithm consists of applying a conventional PDR system to each foot and fusion algorithm combining both. The PDR system using foot-mounted IMU, one on each foot, is based on integration approach separately. The positions of both feet should be in a circle with a radius as step length during walking. The designed filter is constrained so that the position of both feet are in a circular boundary. The heading error that is symmetrically drifted is corrected by the position constraint when the pedestrian moves straight. Experimental results show the performance and usability of each previous algorithm to compensate for symmetric heading errors.

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Li, Chaohong, Hao Xian, Wenhan Jiang, and Changhui Rao. "Wavefront error caused by centroid position random error." Journal of Modern Optics 55, no. 1 (January 10, 2008): 127–33. http://dx.doi.org/10.1080/09500340701321990.

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Jiang, Yu, Na Li, Xuemei Gong, Guorui Jia, and Huijie Zhao. "Improved Position Error Model for Airborne Hyperspectral Imaging Systems." International Journal of Pattern Recognition and Artificial Intelligence 33, no. 05 (April 8, 2019): 1954017. http://dx.doi.org/10.1142/s021800141954017x.

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An improved position error model for airborne hyperspectral imaging systems is proposed to quantify the position errors caused by the deficiencies of instruments and the manual installation of integrated systems. The model is based on a thorough analysis of position error sources, which include uncertainties caused by camera position and altitude, interior camera parameters, gyro stabilized mount, position setting error of the global positioning system antenna, and boresight angle error. An improved position error model that describes these error sources is established based on collinear equations. This model is then expanded into the first-order Taylor series. Finally, the error propagation law is applied to estimate the position errors. The performance of the proposed method is evaluated based on real hyperspectral images of Hymap. Results show that the mean square error of the position error is better than 2.1 pixels, which is almost the same as that of ground truth.

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Pilbeam, Chloë, and Victoria Hood-Moore. "Test–retest reliability of wrist joint position sense in healthy adults in a clinical setting." Hand Therapy 23, no. 3 (April 18, 2018): 100–109. http://dx.doi.org/10.1177/1758998318770227.

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Introduction Proprioceptive assessments of the wrist inform clinical decision making. In wrist rehabilitation, joint position sense has emerged as one way of assessing conscious proprioception with varying methods and minimal psychometric analysis reported. The purpose of this study was to standardise the wrist joint position sense test method for clinical use and to determine its test–retest reliability in a healthy population. Methods Four wrist positions (20° and 45° flexion, 20° and 45° extension) were measured twice in a random order, by a single rater, using a universal goniometer on the same day. The absolute error in degrees between each position and reposition was calculated. For relative reliability analysis, the intraclass correlation coefficient (3,1) was calculated. For absolute reliability the standard error of the measurement was calculated and Bland–Altman plots visually inspected. Results Fifty-five healthy volunteers (mean age 31.1 SD±10.25 years) were assessed. The mean absolute error, summarised for all positions for test and retest, was 3.98°. The intraclass correlation coefficients were poor to fair (0.07–0.47), and standard error of the measurement was 2° (rounded) for all positions. The limits of agreement were fairly narrow, and the Bland–Altman plots showed random distribution of errors for each position, therefore the measurement error was clinically acceptable. Conclusions The active wrist joint position sense test using goniometry demonstrated poor to fair test–retest reliability and acceptable measurement error in healthy volunteers. The wrist joint position sense angle of 20° flexion was the most reliable.

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Ku, SungKwan, Hojong Baik, and Taehyoung Kim. "Analysis of surveillance position error for airfield detection." Aircraft Engineering and Aerospace Technology 90, no. 6 (September 3, 2018): 962–66. http://dx.doi.org/10.1108/aeat-09-2017-0207.

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Purpose The surveillance equipment is one of the most important parts for current air traffic control systems. It provides aircraft position and other relevant information including flight parameters. However, the existing surveillance equipment has certain position errors between true and detected positions. Operators must understand and account for the characteristics on magnitude and frequency of the position errors in the surveillance systems because these errors can influence the safety of aircraft operation. This study aims to develop the simulation model for analysis of these surveillance position errors to improve the safety of aircrafts in airports. Design/methodology/approach This study investigates the characterization of the position errors observed in airport surface detection equipment of an airport ground surveillance system and proposes a practical method to numerically reproduce the characteristics of the errors. Findings The proposed approach represents position errors more accurately than an alternative simple approach. This study also discusses the application of the computational results in a microscopic simulation modeling environment. Practical implications The surveillance error is analyzed from the radar trajectory data, and a random generator is configured to implement these data. These data are used in the air transportation simulation through an application programing interface, which can be applied to the aircraft trajectory data in the simulation. Subsequently, additionally built environment data are used in the actual simulation to obtain the results from the simulation engine. Originality/value The presented surveillance error analysis and simulation with its implementation plan are expected to be useful for air transportation safety simulations.

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Kim, Wonhee, Donghoon Shin, and Youngwoo Lee. "Nonlinear Position Control Using Only Position Feedback under Position Errors and Yaw Constraints for Air Bearing Planar Motors." Mathematics 8, no. 8 (August 13, 2020): 1354. http://dx.doi.org/10.3390/math8081354.

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In this paper, we propose a nonlinear position control using only position feedback to guarantee the tolerances for position tracking errors and yaw. In the proposed method, both mechanical and electrical dynamics are considered. The proposed method consists of the nonlinear position controller and nonlinear observer. The nonlinear position controller is designed by a backstepping procedure using the barrier Lyapunov function to satisfy the constraints of position error and yaw. The nonlinear observer is developed to estimate full state using only position feedback. The stability of the closed-loop system is proven using Lyapunov and input-to-state stabilities. Consequently, the proposed method satisfies the constraints of position error and yaw using only position feedback for the planar motor.

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Erickson, Paul. "Effects of intraocular lens position errors on postoperative refractive error." Journal of Cataract & Refractive Surgery 16, no. 3 (May 1990): 305–11. http://dx.doi.org/10.1016/s0886-3350(13)80699-2.

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Menq, Chia-Hsiang, and Jin-Hwan Borm. "Statistical Characteriztion of Position Errors of an Ensemble of Robots and Its Applications." Journal of Mechanisms, Transmissions, and Automation in Design 111, no. 2 (June 1, 1989): 215–22. http://dx.doi.org/10.1115/1.3258986.

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For the accurate control and implementation of a robot in an integrated manufacturing environment using off-line programming, a knowledge of the absolute positioning accuracy of the robot becomes important. This paper presents a framework which can be used to statistically represent the absolute positioning accuracy for a family of robots. Statistical error measure indices are proposed to represent the position error field over the working space for a family of robots. This error field provides statistical information for the position errors of the end-effector and can be a guide for the determination of the optimal design tolerances of the parts composing of a robot. The second objective of the paper is to introduce a simple interpolation scheme to improve the local position accuracy by teaching one or more task reference frames with which goal positions are mathematically expressed. It will be shown how the method shifts or alters the position error field in order to maintain the desired position accuracy within a desired working area.

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Zhao, Xueqiang, Yunpeng Zhang, Minjie Huang, Peipei Hou, Ren Zhu, Jianfeng Sun, Xia Hou, and Weibiao Chen. "Analysis of detection error for spot position in fiber nutation model." Chinese Optics Letters 18, no. 2 (2020): 020604. http://dx.doi.org/10.3788/col202018.020604.

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Smyth, Mary M., and Keith A. Scholey. "Serial Order in Spatial Immediate Memory." Quarterly Journal of Experimental Psychology Section A 49, no. 1 (February 1996): 159–77. http://dx.doi.org/10.1080/713755615.

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Serial order effects in spatial memory are investigated in three experiments. In the first an analysis of errors in recall data suggested that immediate transpositions were the most common error and that order errors over 2 or 3 adjacent items accounted for the majority of errors in recall. The first and last serial positions are less error-prone than is the middle position in sets of six and seven items. A second experiment investigated recognition of transpositions and found that immediate transpositions were hardest to recognize but that a traditional serial position effect was not found. This may be due to the difficulty of maintaining one set of spatial items when another set is presented for comparison. A probe experiment, in which subjects were asked to recognize whether a single item came from a memory set and then to assign it to its position in the set indicated that the first and last positions were remembered more accurately than were central positions. The combination of serial order data in recall and position data suggests that there are similarities between serial order and position effects in the verbal and spatial domains and that serial order in spatial sequences is position-based.

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He, G. Y., C. X. Hu, and X. Liu. "Evaluation Modeling and Optimal Adjustment of Position Error Based on Localization Sensitivity Analysis." Materials Science Forum 697-698 (September 2011): 258–61. http://dx.doi.org/10.4028/www.scientific.net/msf.697-698.258.

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Sensitivity analysis is to evaluate how sensitive the surface deviation of a workpiece is to a geometric error of locator. With this thinking, the relationship between geometric error of locators and the position error of holes group is presented. The fixture system errors model and evaluation model of position errors are established. Furthermore with both models, a method of optimizing the position errors by adjusting the locators’ position is presented, which can get to accuracy localization. At last, a simulation study is used to verify the method.

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de Wit, C. "Optimal Position Estimate from a Stars Fix with Correlated Errors." Journal of Navigation 45, no. 1 (January 1992): 126–33. http://dx.doi.org/10.1017/s0373463300010535.

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This paper concerns the estimate of a ship's position from a sequence of measurements of 3, 4 or 5 altitudes of stars or planets. The measurement errors are assumed to be mutually correlated. This correlation is mainly caused by the appearance of so-called systematic errors. It is the main intention of this paper to dispense with the policy of pre-separation of these systematic errors. Instead, the equal contribution of some partial errors to the total measuring errors is fully accounted for by the formation of the covariance matrix, which corresponds with the vector of measurement errors. The algorithm produces a position estimate with a bias-free estimation error, meaning that the estimate and the error are stochastically independent. The resulting covariance matrix of the position error has a minimal trace.

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Rubtsov, E. A. "Error distributions in aircraft position determination." VESTNIK of the Samara State Aerospace University, no. 1(43) (July 30, 2014): 267. http://dx.doi.org/10.18287/1998-6629-2014-0-1(43)-267-274.

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Meise, Ruth, Kerstin Lüdtke, Annette Probst, Philipp Stude, and Thomas Schöttker-Königer. "Zervikaler „joint position error“ bei Kopfschmerzen." Der Schmerz 33, no. 3 (April 24, 2019): 204–11. http://dx.doi.org/10.1007/s00482-019-0369-z.

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Specht, Mariusz. "Consistency of the Empirical Distributions of Navigation Positioning System Errors with Theoretical Distributions—Comparative Analysis of the DGPS and EGNOS Systems in the Years 2006 and 2014." Sensors 21, no. 1 (December 23, 2020): 31. http://dx.doi.org/10.3390/s21010031.

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Positioning systems are used to determine position coordinates in navigation (air, land and marine). The accuracy of an object’s position is described by the position error and a statistical analysis can determine its measures, which usually include: Root Mean Square (RMS), twice the Distance Root Mean Square (2DRMS), Circular Error Probable (CEP) and Spherical Probable Error (SEP). It is commonly assumed in navigation that position errors are random and that their distribution are consistent with the normal distribution. This assumption is based on the popularity of the Gauss distribution in science, the simplicity of calculating RMS values for 68% and 95% probabilities, as well as the intuitive perception of randomness in the statistics which this distribution reflects. It should be noted, however, that the necessary conditions for a random variable to be normally distributed include the independence of measurements and identical conditions of their realisation, which is not the case in the iterative method of determining successive positions, the filtration of coordinates or the dependence of the position error on meteorological conditions. In the preface to this publication, examples are provided which indicate that position errors in some navigation systems may not be consistent with the normal distribution. The subsequent section describes basic statistical tests for assessing the fit between the empirical and theoretical distributions (Anderson-Darling, chi-square and Kolmogorov-Smirnov). Next, statistical tests of the position error distributions of very long Differential Global Positioning System (DGPS) and European Geostationary Navigation Overlay Service (EGNOS) campaigns from different years (2006 and 2014) were performed with the number of measurements per session being 900’000 fixes. In addition, the paper discusses selected statistical distributions that fit the empirical measurement results better than the normal distribution. Research has shown that normal distribution is not the optimal statistical distribution to describe position errors of navigation systems. The distributions that describe navigation positioning system errors more accurately include: beta, gamma, logistic and lognormal distributions.

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Zhang, Fei Hu, Xing Bin Yu, and Yong Zhang. "Analysis of Tangential Position Error or Removal Function Error in Ultrasonic-Magnetorheological Combined Finishing." Key Engineering Materials 516 (June 2012): 390–95. http://dx.doi.org/10.4028/www.scientific.net/kem.516.390.

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Ultrasonic-magnetorheological combined finishing (UMCF) is a new technique for the ultra precision machining of aspheric surfaces, especially for high quality work pieces with small curvature radius concave surfaces. The goal with UMCF is to minimize surface figure errors by optimizing the dwell time and tool path, and the current approach typically results in low amplitude form errors. However, discrepancies exist between the predicted and observed form errors. The major sources of such errors are machine axes positioning errors and unpredicted variations of the removal function. Errors that can produce discrepancies between actual and predicted removal profiles were modelled. A diagnostic method was developed to determine the residual error induced by two types of error. Their effects were examined with numerical simulations and the simulation result was presented. Finally, UMCF experiments are performed on a variety of optical surfaces. The final residual error after polishing is less than 2.6 nm PV values. The successful figuring results prove the validity and advantages of UMCF.

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Ямников, Александр, Aleksandr Yamnikov, Ольга Ямникова, Ol'ga Yamnikova, Иван Матвеев, Ivan Matveev, Елена Родионова, and Elena Rodionova. "IMPACT OF POSITION ERROR OF COMPOSITE AXISYMMETRIC BODY JOINT SURFACES UPON POSITION ERROR OF EXECUTING SURFACES." Bulletin of Bryansk state technical university 2017, no. 7 (December 15, 2017): 13–17. http://dx.doi.org/10.12737/article_5a337fbbafffe3.34523889.

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Wei, Xiang, Bing Li, Lei Chen, Lin Sun, Meiting Xin, and Bingcai Liu. "Position error correction of large-aperture aspherical in-position measurement." Review of Scientific Instruments 88, no. 6 (June 2017): 065101. http://dx.doi.org/10.1063/1.4984123.

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Zeng, Wenhui, Fang Fang, and Xiao Ma. "On-position Measurement Method for Position-error Compensation in Machining." International Journal of Precision Engineering and Manufacturing 22, no. 7 (June 4, 2021): 1179–89. http://dx.doi.org/10.1007/s12541-021-00528-8.

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Li, Ke Ke, Yu Shu Bian, and Bing Dong Liu. "Transmission Error Analysis of External Gear Drive Based on Form and Position Errors." Applied Mechanics and Materials 614 (September 2014): 36–39. http://dx.doi.org/10.4028/www.scientific.net/amm.614.36.

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The key factors affecting the transmission error of gear mechanism are analyzed and the calculation formula of transmission error based on parts’ form and position errors is derived in this paper. Since the errors have different kinds of probability distributions, this paper calculate the expectation and variance of transmission error by statistical method, gives final transmission error value, and verify it by an example.

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Iribar, Imanol Basterretxea, Jesús Angel Vila Muñoz, and Carlos Angel Pérez Labajos. "Latitude Error in Compass Deviation: Mathematical Method to Determine the Latitude Error in Magnetic Compass Deviation." Polish Maritime Research 21, no. 3 (October 28, 2014): 25–31. http://dx.doi.org/10.2478/pomr-2014-0026.

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AbstractThis article aims to provide the seafarer with a tool to calculate the deviation for a righted ship in any geographical position using only the information available on board. In this way the accidental errors in the deviation card are reduced and the latitude error is made negligible. Moreover, an experimental application of this method is carried out on board a tanker to compare the latitude error in different positions at sea.

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Chen, Ying, Xia Jiang Zhang, Yuan Yuan Xue, Zhen Kang, and Ting Shang. "Application of Kalman Filter Technology to Integrated INS/DR Navigation System for Land Vehicle." Applied Mechanics and Materials 411-414 (September 2013): 912–16. http://dx.doi.org/10.4028/www.scientific.net/amm.411-414.912.

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Strap-down INS is composed of fiber gyroscope. Position error propagation equation and position update algorithm of dead reckoning is deduced in this paper. The Kalman filter is proposed for compensation error of integrated system. The difference of velocity between INS and DR is used as the input of Kalman filter, attitude error, velocity error, position error and scale factor error are to be estimated which compensate and rectify the errors of integrated navigation system. By carrying out experiment upon vehicular navigation system in use of Kalman filter, the errors of integrated navigation system are estimated accurately. Experiment result show that the method not only can effectively improve precision of the system, but also is simple and convenient, so it is more suitable for practical application.

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Zhao, Lin, Jie Zhang, Liang Li, Fuxin Yang, and Xiaosong Liu. "Position-Domain Non-Gaussian Error Overbounding for ARAIM." Remote Sensing 12, no. 12 (June 21, 2020): 1992. http://dx.doi.org/10.3390/rs12121992.

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The non-Gaussian observation error is a threat for advanced receiver autonomous integrity monitoring (ARAIM), because the protection level of ARAIM based on the Gaussian distribution assumption is insufficient to envelope the positioning error (PE), and the probability of hazardously misleading information (PHMI) is difficult to be satisfied. The traditional non-Gaussian overbounding method is limited by the correlation among observation errors, and the deteriorated continuity risk resulting from the conservative inflation factor for overbounding, simultaneously. We propose an enhanced ARAIM method by position-domain non-Gaussian error overbounding. Furthermore, the upper bound of the inflation factor is imposed to release the conservativeness of overbounding. The simulation and the real-world data are utilized to test the proposed method. The simulation experiment has shown that the global worldwide availability level can be increased to 99.99% by using the proposed method. The real-word data experiment reveals that the proposed method can simultaneously satisfy the integrity risk and continuity risk with the boundary of the inflation factor.

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Cao, Chi-Tho, Van-Phu Do, and Byung-Ryong Lee. "A Novel Indirect Calibration Approach for Robot Positioning Error Compensation Based on Neural Network and Hand-Eye Vision." Applied Sciences 9, no. 9 (May 11, 2019): 1940. http://dx.doi.org/10.3390/app9091940.

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It is well known that most of the industrial robots have excellent repeatability in positioning. However, the absolute position errors of industrial robots are relatively poor, and in some cases the error may reach even several millimeters, which make it difficult to apply the robot system to vehicle assembly lines that need small position errors. In this paper, we have studied a method to reduce the absolute position error of robots using machine vision and neural network. The position/orientation of robot tool-end is compensated using a vision-based approach combined with a neural network, where a novel indirect calibration approach is presented in order to gather information for training the neural network. In the simulation, the proposed compensation algorithm was found to reduce the positional error to 98%. On average, the absolute position error was 0.029 mm. The application of the proposed algorithm in the actual robot experiment reduced the error to 50.3%, averaging 1.79 mm.

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Базров, Борис, and Boris Bazrov. "Problems in estimate of parts geometrical accuracy." Science intensive technologies in mechanical engineering 2018, no. 4 (April 19, 2018): 8–12. http://dx.doi.org/10.12737/article_5aacd85793bdc2.44830790.

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The paper reports the analysis of the method for parts geometrical accuracy definition which includes the following stages: part surfaces measurement, a representation of measurement results and their relative position, a definition without errors count and a definition of surface errors. There are shown drawbacks of stages enumerated such as a neglect of measurement base surface errors, an ambiguity of measurement base positions regarding surfaces under control, use of bases of error account and criteria for errors estimate irrespective of surface operation functions. A multi-gradation of the method for the estimate of a part error resulting in the accumulation of total error is shown.

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Wang, Zhihao, Wenliang Chen, Min Wang, Qinghe Xu, and Can Huang. "Kinematic calibration of bracket type parallel posture alignment mechanism considering the gravity effect." Industrial Robot: the international journal of robotics research and application 46, no. 5 (August 19, 2019): 581–98. http://dx.doi.org/10.1108/ir-09-2018-0183.

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Purpose The purpose of this study is to improve the position and posture accuracy of posture alignment mechanism. The automatic drilling and riveting machine is an important equipment for aircraft assembly. The alignment accuracy of position and posture of the bracket type posture alignment mechanism has a great influence on the operation effect of the machine. Therefore, it is necessary to carry out the kinematic calibration. Design/methodology/approach Based on analysis of elastic deformation of the bracket and geometric errors of the posture alignment mechanism, an improved method of kinematic calibration was proposed. The position and posture errors of bracket caused by geometric errors were separated from those caused by gravity. The method of reduction of dimensions was applied to deal with the error coefficient matrix in error identification, and it did not change the coefficient of the error terms. The target position and its posture were corrected to improve the error compensation accuracy. Furthermore, numerical simulation and experimental verification were carried out. Findings The simulation and experimental results show that considering the influence of the elastic deformation of the bracket on the calibration effect, the error identification accuracy and compensation accuracy can be improved. The maximum value of position error is reduced from 5.33 mm to 1.60 × 10−1 mm and the maximum value of posture error is reduced from 1.07 × 10−3 rad to 6.02 × 10−4 rad, which is superior to the accuracy without considering the gravity factor. Originality/value This paper presents a calibration method considering the effects of geometric errors and gravity. By separating position and posture errors caused by different factors and correcting the target position and its posture, the results of the calibration method are greatly improved. The proposed method might be applied to any parallel mechanism based on the positioner.

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Duffie, N. A., and S. J. Malmberg. "Error Diagnosis and Compensation Using Kinematic Models and Position Error Data." CIRP Annals 36, no. 1 (1987): 355–58. http://dx.doi.org/10.1016/s0007-8506(07)62621-3.

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Liu, Fang, Ming Lyn, and Haohao Hou. "A Calibration Method of Phase Error Caused by Target’s Position Error." Procedia Computer Science 187 (2021): 188–93. http://dx.doi.org/10.1016/j.procs.2021.04.050.

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Peng, J., J. Cai, and H. Yang. "A RAIL CENTRAL DISPLACEMENT METHOD ABOUT GB-SAR." ISPRS - International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences XLI-B7 (June 22, 2016): 865–71. http://dx.doi.org/10.5194/isprsarchives-xli-b7-865-2016.

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This paper presents a new method to correct rail errors of Ground Based Synthetic Aperture Radar (GB-SAR) in the discontinue mode. Generally, “light positioning” is performed to mark the GB-SAR position in the dis-continuous observation mode. Usually we assume there is no difference between the marked position and the real installation position. But in fact, it is hard to keep the GB-SAR positions of two campaigns the same, so repositioning errors can’t be neglected. In order to solve this problem, we propose an algorithm to correct the rail error after analyzing the GB-SAR rail error geometry. Results of the simulation experiment and the real experiment of a landslide in Lvliang, Shanxi, China, show the proposed method achieves an mm-level precision, enabling the D-GBSAR mode to be used in engineering projects.

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Peng, J., J. Cai, and H. Yang. "A RAIL CENTRAL DISPLACEMENT METHOD ABOUT GB-SAR." ISPRS - International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences XLI-B7 (June 22, 2016): 865–71. http://dx.doi.org/10.5194/isprs-archives-xli-b7-865-2016.

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This paper presents a new method to correct rail errors of Ground Based Synthetic Aperture Radar (GB-SAR) in the discontinue mode. Generally, “light positioning” is performed to mark the GB-SAR position in the dis-continuous observation mode. Usually we assume there is no difference between the marked position and the real installation position. But in fact, it is hard to keep the GB-SAR positions of two campaigns the same, so repositioning errors can’t be neglected. In order to solve this problem, we propose an algorithm to correct the rail error after analyzing the GB-SAR rail error geometry. Results of the simulation experiment and the real experiment of a landslide in Lvliang, Shanxi, China, show the proposed method achieves an mm-level precision, enabling the D-GBSAR mode to be used in engineering projects.

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Gade, Kenneth. "A Non-singular Horizontal Position Representation." Journal of Navigation 63, no. 3 (May 28, 2010): 395–417. http://dx.doi.org/10.1017/s0373463309990415.

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Position calculations, e.g. adding, subtracting, interpolating, and averaging positions, depend on the representation used, both with respect to simplicity of the written code and accuracy of the result. The latitude/longitude representation is widely used, but near the pole singularities, this representation has several complex properties, such as error in latitude leading to error in longitude. Longitude also has a discontinuity at ±180°. These properties may lead to large errors in many standard algorithms. Using an ellipsoidal Earth model also makes latitude/longitude calculations complex or approximate. Other common representations of horizontal position include UTM and local Cartesian ‘flat Earth’ approximations, but these usually only give approximate answers, and are complex to use over larger distances. The normal vector to the Earth ellipsoid (called n-vector) is a non-singular position representation that turns out to be very convenient for practical position calculations. This paper presents this representation, and compares it with other alternatives, showing that n-vector is simpler to use and gives exact answers for all global positions, and all distances, for both ellipsoidal and spherical Earth models. In addition, two functions based on n-vector are presented, that further simplify most practical position calculations, while ensuring full accuracy.

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Yan, Youyu, Yan Ma, and Jianguo Liu. "Analysis and Correction of the Magnetometer’s Position Error in a Cross-Shaped Magnetic Tensor Gradiometer." Sensors 20, no. 5 (February 27, 2020): 1290. http://dx.doi.org/10.3390/s20051290.

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When using the technique of magnetic gradient tensor measurements to obtain the position of magnetic objects, calibration of the magnetic tensor gradiometer plays a pivotal role in precisely locating the target, and extensive research has been carried out on this up to now. However, previous studies have always lacked sufficient discussion on the position error of magnetometers in magnetic tensor gradiometers caused by inaccurate installment of magnetometers. In this paper, we analyze and correct this position error based on a magnetic dipole source. The result of the simulation exemplifies that the magnetometer’s position error will affect the locating accuracy and, therefore, it is worth correcting this error. The relationship between position error and magnetic gradient tensor components is established, followed by an error correction method based on this relationship. Simulations illustrate that this method can effectively decrease the effect caused by the position error of magnetometers and improve the locating performance with locating error and magnetic moment errors dropping from 2 to 0.2 m and 6 × 10 5 A ⋅ m 2 to 5 × 10 4 A ⋅ m 2 , respectively.

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Liu, Ping, and Hui Yi Miao. "Research on a Computerized Form and Position Error Measurement Instrument." Applied Mechanics and Materials 201-202 (October 2012): 151–56. http://dx.doi.org/10.4028/www.scientific.net/amm.201-202.151.

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A model machine of multifunctional form and position measurement instrument controlled by a personal computer has been successfully developed. The instrument is designed in rotary table type with a high precision air bearing and the radial rotation error of the rotary table is 0.08 μm. A high precision vertical sliding carriage supported by an air bearing is used to the instrument, the straight motion error of the carriage is 0.3 μm/200 mm and the parallelism error of the motion of the carriage relative to the rotation axis of the rotary table is 0.4 μm/200 mm. The mathematical models have been established for assessing planar and spatial straightness, flatness, roundness, cylindricity, and coaxality errors. By radial deviation measurement, the instrument can accurately measure form and position errors of such workpieces as shafts, round plates and sleeves of medium or small dimensions with the tolerance grades mostly used in industry.

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Nguyen, Hoai-Nhan, Phu-Nguyen Le, and Hee-Jun Kang. "A new calibration method for enhancing robot position accuracy by combining a robot model–based identification approach and an artificial neural network–based error compensation technique." Advances in Mechanical Engineering 11, no. 1 (January 2019): 168781401882293. http://dx.doi.org/10.1177/1687814018822935.

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Robot position accuracy plays a very important role in advanced industrial applications. This article proposes a new method for enhancing robot position accuracy. In order to increase robot accuracy, the proposed method models and identifies determinable error sources, for instance, geometric errors and joint deflection errors. Because non-geometric error sources such as link compliance, gear backlash, and others are difficult to model correctly and completely, an artificial neural network is used for compensating for the robot position errors, which are caused by these non-geometric error sources. The proposed method is used for experimental calibration of an industrial Hyundai HH800 robot designed for carrying heavy loads. The robot position accuracy after calibration demonstrates the effectiveness and correctness of the method.

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Wang, Zhen Huan, Xi Jun Chen, and Qing Shuang Zeng. "SINS Installation Error Calibration Based on Multi-Position Combinations." Advanced Materials Research 383-390 (November 2011): 4213–20. http://dx.doi.org/10.4028/www.scientific.net/amr.383-390.4213.

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A new method is proposed to calibrate the installation errors of SINS. According to the method, the installation errors of the gyro and accelerometer can be calibrated simultaneously, which not depend on latitude, gravity, scale factor and earth's rotation rate. By the multi-position combinations, the installation errors of the gyro and accelerometer are modulated into the sine and cosine functions, which can be identified respectively based on the least squares. In order to verify the correctness of the theoretical analysis, the SINS is experimented by a three-axis turntable, and the installation errors of the gyro and accelerometer are identified respectively according to the proposed method. After the compensation of the installation error, the accuracy of the SINS is improved significantly.

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Hinckfuss, Simon, Heather J. Conrad, Lianshan Lin, Scott Lunos, and Wook-Jin Seong. "Effect of Surgical Guide Design and Surgeon's Experience on the Accuracy of Implant Placement." Journal of Oral Implantology 38, no. 4 (August 1, 2012): 311–23. http://dx.doi.org/10.1563/aaid-joi-d-10-00046.

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Implant position is a key determinant of esthetic and functional success. Achieving the goal of ideal implant position may be affected by case selection, prosthodontically driven treatment planning, site preparation, surgeon's experience and use of a surgical guide. The combined effect of surgical guide design, surgeon's experience, and size of the edentulous area on the accuracy of implant placement was evaluated in a simulated clinical setting. Twenty-one volunteers were recruited to participate in the study. They were divided evenly into 3 groups (novice, intermediate, and experienced). Each surgeon placed implants in single and double sites using 4 different surgical guide designs (no guide, tube, channel, and guided) and written instructions describing the ideal implant positions. A definitive typodont was constructed that had 3 implants in prosthetically determined ideal positions of single and double sites. The position and angulation of implants placed by the surgeons in the duplicate typodonts was measured using a computerized coordinate measuring machine and compared to the definitive typodont. The mean absolute positional error for all guides was 0.273, 0.340, 0.197 mm in mesial-distal, buccal-lingual, vertical positions, respectively, with an overall range of 0.00 to 1.81 mm. The mean absolute angle error for all guides was 1.61° and 2.39° in the mesial-distal and buccal-lingual angulations, respectively, with an overall range of 0.01° to 9.7°. Surgical guide design had a statistically significant effect on the accuracy of implant placement regardless of the surgeon's experience level. Experienced surgeons had significantly less error in buccal-lingual angulation. The size of the edentulous sites was found to affect both implant angle and position significantly. The magnitude of error in position and angulation caused by surgical guide design, surgeon's experience, and site size reported in this study are possibly not large enough to be clinically significant; however, it is likely that errors would be magnified in clinical practice. Future research is recommended to evaluate the effect of surgical guide design in vivo on implant angulation and position error.

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Backes, P. G., G. G. Leininger, and Chun-Hsien Chung. "Joint Self-Tuning With Cartesian Setpoints." Journal of Dynamic Systems, Measurement, and Control 108, no. 2 (June 1, 1986): 146–50. http://dx.doi.org/10.1115/1.3143757.

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A joint coordinate self-tuning manipulator control method is presented which uses Cartesian setpoints. The method is capable of both position and hybrid control. Position and force errors are transformed from Cartesian coordinates to position and force errors at the joints. The position and force errors at each joint are combined into one hybrid error that is eliminated using pole-placement self-tuning. Real time position and hybrid control results are given. No prior knowledge of manipulator or load dynamics is required and real time control results show that the goal of consistent control with changing load dynamics is achieved. The major cause of error in position and hybrid control is the large friction effects in the joints.

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Chen, Xiao Gang, Zhao Tang Xu, and Hai Bing Wu. "Kinematic Error Analysis of Parallel Machine Tool Based on Rigid Body Dynamics." Applied Mechanics and Materials 743 (March 2015): 71–78. http://dx.doi.org/10.4028/www.scientific.net/amm.743.71.

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To estimate influence of velocity on kinematic accuracy for a cross-linked Stewart type Parallel Machine Tool, position and orientation errors of the moving tool platform are researched. Based on rigid body dynamics, inertial and friction forces and moments are considered. Firstly, analytical expression of driving force is derived for each link. Secondly, change of length is derived using Hooke’s Law for each link. Then mapping matrix between change of link length and change of platform position and orientation is derived based on both Euler angle and revolving angle around a spatial axis. Finally, analytical expression of position and orientation errors of the moving platform is derived. Figures of distribution of position and orientation errors in workspace under two velocities are obtained respectively. The results show that, in frequently used workspace, all of the three components of position error are less than 3.5μm. All of them increase with z coordinate of platform center. Position error is influenced slightly by velocity. The difference of position error between two velocities is less than 2%.

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Cooper, E., and R. Hampshire. "Adaptive compensation for position error signal nonlinearity." IEEE Transactions on Magnetics 38, no. 3 (May 2002): 1593–602. http://dx.doi.org/10.1109/20.999135.

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Liberman, Y. L. "Reduction of quantization error in position encoders." IOP Conference Series: Materials Science and Engineering 709 (January 3, 2020): 022062. http://dx.doi.org/10.1088/1757-899x/709/2/022062.

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Chen, Shaowu, Gang Ji, Dezhen Xu, Haitao Li, and Guangliang Dong. "Relative Position Error Analysis for Mars Probes." TELKOMNIKA (Telecommunication Computing Electronics and Control) 14, no. 3A (September 1, 2016): 161. http://dx.doi.org/10.12928/telkomnika.v14i3a.4389.

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Cho, Yong-Kwon, Carl T. Haas, S. V. Sreenivasan, and Katherine Liapi. "Position Error Modeling for Automated Construction Manipulators." Journal of Construction Engineering and Management 130, no. 1 (February 2004): 50–58. http://dx.doi.org/10.1061/(asce)0733-9364(2004)130:1(50).

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MAO Jie, 毛洁, 侯溪 HOU Xi, and 伍凡 WU Fan. "Position Error Analysis in Radius Interferometric Measurements." ACTA PHOTONICA SINICA 44, no. 7 (2015): 712003. http://dx.doi.org/10.3788/gzxb20154407.0712003.

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Trivedi, Richa. "Study of GPS Position Error during 16 June, 2005 (Disturb Day) at Bhopal." Circulation in Computer Science SED2017, no. 01 (April 9, 2017): 1–4. http://dx.doi.org/10.22632/sed-2017-ccs417.

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In order to study GPS position error, the GPS Ionospheric Scintillation and TEC Monitor (GISTM) based GPS receiver was installed at an equatorial station, Bhopal (23.2° N, 77.4° E, Geomagnetic latitude 14.23˚ N), India. We analyzed the horizontal error and the level of confidence in terms of DRMS and CEP and positional error from fixed GPS point for 16 June 2005(disturb day). In order to study the effect of storm on GPS position errors, the latitudinal error and longitudinal error in meter is studied. We observed that the maximum number of error points in the latitudinal error lies between 1.95 to -1.57 meter while longitudinal error points lies between 1.09 to – 1.28 meter. It was observed that some of the error points lie out the 95% error ellipse and it is observed that the error point’s increased in N and N-E direction. The results have been compared with the earlier ones and discussed in terms of possible source mechanism responsible for the position error at anomaly crest region.

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Ding, Yuan Ming, Gang Xiang Guo, and Jin Wei Chen. "Research on Method of Serial Robot Relative Position Correction." Applied Mechanics and Materials 719-720 (January 2015): 405–10. http://dx.doi.org/10.4028/www.scientific.net/amm.719-720.405.

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For the problem of serial robot structure error, method of relative position correction was researched. An adaptive filtering correction method based on robot joint position feedback was proposed. The method built a robot joint adaptive filtering corrector (AFC) to correct robot joint feedback. The real spatial position of robot end-effector can be got through the forward kinematics computation with the corrected joint feedback. Thus, the robot structure error is corrected. Weights matrices of AFC were trained with relative positions between calibration points on the standard calibration module. The proposed method of relative positions correction provides a new way for serial robot structure error correction, which does not directly modify the robot kinematics design parameters, dose not need measuring equipment, and can be applied in field. The simulation results got with LabVIEW robot module show that the corrected trajectory of robot end-effector is more approaching to its true trajectory than before, which means the robot structure error is effectively corrected.Keywords: Correction; Relative position; Serial robot; Kinematics

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Zhang, Jian Ye, Chen Zhao, and Da Wei Zhang. "Error Modelling for Master Slave Surgical Robot System." Materials Science Forum 697-698 (September 2011): 795–98. http://dx.doi.org/10.4028/www.scientific.net/msf.697-698.795.

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The Position and orientation accuracy of robot manipulator has long become a major issue to be considered in its advanced application. A linear error model that described the end-effector position and orientation errors of the master salve surgical robot system due to kinematics parameters errors has been presented. A computer program to perform the accuracy analysis has been developed in MATLAB. This methodology and software are applied to the accuracy analysis of a master-slave surgical robot system. The position error in its workspace cross section (XOZ) has been plotted as 3D surface graph and discussed.

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Journal articles on the topic 'Position Error'

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