scholarly journals A method for selfcalibration of a magneto-resistive angular position sensor in servo systems

Tehnika ◽  
2020 ◽  
Vol 75 (4) ◽  
pp. 469-476
Author(s):  
Vladimir Čeperković ◽  
Vujo Drndarević
Keyword(s):  
Measurement Error ◽  
Process Model ◽  
Least Squares Method ◽  
Angular Position ◽  
System Control ◽  
Residual Variance ◽  
Position Measurement ◽  
Internal Reference ◽  
Harmonic Compensation ◽  
Servo Systems

Magneto-resistive and Hall angular position sensors are frequently used in servo systems, due to their reliability, longevity, and tolerance to environmental conditions. In this paper, a measurement error compensation is integrated into the servo system control structure. The compensation consists of two steps: a linear compensation of the magnetic field vector measurement error, and harmonic compensation of the angular position measurement error. The selfcalibration method uses data collected during rotation with maximal speed to identify parameters of the measurement process model. Identification is executed periodically, each time when the shaft makes a full rotation. The least squares method is utilized for identification of the linear compensation parameters, while the average rotational speed is used as an internal reference for the harmonic compensation parameters identification. The method, together with a fast convergence, increases the measurement accuracy by an order of magnitude. Experimentally achieved measurement error is below 0.7°, with residual variance below 0.05°, comparable with sensor differentiability.

scholarly journals Assessment of the Accuracy of Determining the Angular Position of the Unmanned Bathymetric Surveying Vehicle Based on the Sea Horizon Image

Sensors ◽  
2019 ◽  
Vol 19 (21) ◽  
pp. 4644 ◽  
Author(s):  
Naus ◽  
Marchel ◽  
Szymak ◽  
Nowak
Keyword(s):  
Angular Position ◽  
Complementary Metal Oxide Semiconductor ◽  
General Concept ◽  
Oxide Semiconductor ◽  
Position Measurement ◽  
The Matrix ◽  
Horizon Line ◽  
Aerial Vehicle ◽  
Line Slope ◽  
Further Development

The paper presents the results of research on assessing the accuracy of angular position measurement relative to the sea horizon using a camera mounted on an unmanned bathymetric surveying vehicle of the Unmanned Surface Vehicle (USV) or Unmanned Aerial Vehicle (UAV) type. The first part of the article presents the essence of the problem. The rules of taking the angular position of the vehicle into account in bathymetric surveys and the general concept of the two-camera tilt compensator were described. The second part presents a mathematical description of the meters characterizing a resolution and a mean error of measurements, made on the base of the horizon line image, recorded with an optical system with a Complementary Metal-Oxide Semiconductor (CMOS) matrix. The phenomenon of the horizon line curvature in the image projected onto the matrix that appears with the increase of the camera height has been characterized. The third part contains an example of a detailed analysis of selected cameras mounted on UAVs manufactured by DJI, carried out using the proposed meters. The obtained results including measurement resolutions of a single-pixel and mean errors of the horizon line slope measurement were presented in the form of many tables and charts with extensive comments. The final part presents the general conclusions from the performed research and a proposal of directions for their further development.

Fuzzy Control of an Inverted Pendulum

1996 ◽  
Author(s):  
Tuna Balkan ◽  
Mehmet Emin Ari
Keyword(s):  
Inverted Pendulum ◽  
Fuzzy Controller ◽  
Angular Position ◽  
Upright Position ◽  
Control Signal ◽  
Position Measurement ◽  
Pendulum System ◽  
Inverted Pendulum System ◽  
And Performance ◽  
The Stability

Abstract An inverted pendulum system has been designed and constructed as a physical model of inherently unstable mechanical systems. The vertical upright position of a pendulum is controlled by changing the horizontal position of a cart to which the pendulum is hinged. The stability of the system has been investigated when a fuzzy controller is used to produce the control signal, while making a single measurement. It has been shown that by using simple fuzzy rules to allow real time computation with a single angular position measurement, the system can not be made absolutely stable. However, the stability and performance of the system have been considerably improved by shrinking the membership functions of angular position, computed angular velocity and control signal when inverted pendulum is very close to the vertical upright position.

Design of Holonic Manufacturing Execution System with Control Mechanism Based Stigmergy

2010 ◽  
Vol 102-104 ◽  
pp. 776-780 ◽  
Author(s):  
Xiu Lin Li ◽  
Jian Sha Lu ◽  
Guo Zhong Chai ◽  
Hong Tao Tang
Keyword(s):  
Production Process ◽  
Process Model ◽  
Raw Material ◽  
System Stability ◽  
System Control ◽  
Manufacturing Execution System ◽  
Dynamic Information ◽  
Production Factors ◽  
Cooperation Mechanism ◽  
Manufacturing Execution

To deal with problem of manufacturing system stability caused by uncertain factors in discrete production process, holon was introduced to manufacturing execution system (MES). A distributed manufacturing control architecture based on holon was established. This architecture using cooperation mechanism based stigmergy to realize agility, autonomy and intelligence of system control. Based on the architecture, holon driven agents to visit production elements, acquiring dynamic information of production process. Model design of production factors as order, resource, raw material, product and management factors as optimize, execution was described amply. Finally, workflow of this system was depicted with an example of uncertain order factor.

Continuous wave Nd:YAG laser beam angular position measurement and stabilization

1995 ◽  
Author(s):  
Vadim A. Parfenov ◽  
Sergey N. Rodin ◽  
Ilya S. Etsin ◽  
Gennady F. Zajtsev ◽  
Sergey V. Kruzhalov ◽  
...  
Keyword(s):  
Laser Beam ◽  
Nd:Yag Laser ◽  
Continuous Wave ◽  
Angular Position ◽  
Position Measurement

scholarly journals Generalized Nonlinear Least Squares Method for the Calibration of Complex Computer Code Using a Gaussian Process Surrogate

Entropy ◽  
2020 ◽  
Vol 22 (9) ◽  
pp. 985
Author(s):  
Youngsaeng Lee ◽  
Jeong-Soo Park
Keyword(s):  
Gaussian Process ◽  
Least Squares ◽  
Covariance Matrix ◽  
Process Model ◽  
Least Squares Method ◽  
Nonlinear Least Squares ◽  
Computer Code ◽  
Test Functions ◽  
Unknown Parameters ◽  
Complex Computer

The approximated nonlinear least squares (ALS) method has been used for the estimation of unknown parameters in the complex computer code which is very time-consuming to execute. The ALS calibrates or tunes the computer code by minimizing the squared difference between real observations and computer output using a surrogate such as a Gaussian process model. When the differences (residuals) are correlated or heteroscedastic, the ALS may result in a distorted code tuning with a large variance of estimation. Another potential drawback of the ALS is that it does not take into account the uncertainty in the approximation of the computer model by a surrogate. To address these problems, we propose a generalized ALS (GALS) by constructing the covariance matrix of residuals. The inverse of the covariance matrix is multiplied to the residuals, and it is minimized with respect to the tuning parameters. In addition, we consider an iterative version for the GALS, which is called as the max-minG algorithm. In this algorithm, the parameters are re-estimated and updated by the maximum likelihood estimation and the GALS, by using both computer and experimental data repeatedly until convergence. Moreover, the iteratively re-weighted ALS method (IRWALS) was considered for a comparison purpose. Five test functions in different conditions are examined for a comparative analysis of the four methods. Based on the test function study, we find that both the bias and variance of estimates obtained from the proposed methods (the GALS and the max-minG) are smaller than those from the ALS and the IRWALS methods. Especially, the max-minG works better than others including the GALS for the relatively complex test functions. Lastly, an application to a nuclear fusion simulator is illustrated and it is shown that the abnormal pattern of residuals in the ALS can be resolved by the proposed methods.

scholarly journals Decoupled Six-Axis Force–Moment Sensor with a Novel Strain Gauge Arrangement and Error Reduction Techniques

Sensors ◽  
2019 ◽  
Vol 19 (13) ◽  
pp. 3012 ◽  
Author(s):  
Getnet Ayele Kebede ◽  
Anton Royanto Ahmad ◽  
Shao-Chun Lee ◽  
Chyi-Yeu Lin
Keyword(s):  
Measurement Error ◽  
Strain Gauge ◽  
Least Squares Method ◽  
High Sensitivity ◽  
Error Reduction ◽  
Strain Gauges ◽  
Calibration Error ◽  
Reduction Techniques ◽  
Force Moment ◽  
Sensor Measurement

In this study, a novel strain gauge arrangement and error reduction techniques were proposed to minimize crosstalk reading and simultaneously increase sensitivity on a decoupled six-axis force–moment (F/M) sensor. The calibration process that comprises the least squares method and error reduction techniques was implemented to obtain a robust decoupling matrix. A decoupling matrix is very crucial for minimizing error and crosstalk. A novel strain gauge arrangement that comprised double parallel strain gauges in the decoupled six-axis force–moment sensor was implemented to obtain high sensitivity. The experimental results revealed that the maximum calibration error, F/M sensor measurement error, and crosstalk readings were reduced to 3.91%, 1.78%, and 4.78%, respectively.

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