Error Calibration Method Research Articles

Thermal calibration for triaxial gyroscope of MEMS-IMU based on segmented systematic method

With the progress of micro electromechanical system (MEMS) technology, the performance of MEMS inertial measurement unit (IMU) composed of gyroscopes and accelerometers has been improved. Among the inertial sensors, MEMS triaxial gyroscope plays an important role in attitude estimation, navigation and positioning of intelligent mobile terminals such as unmanned aerial vehicles and unmanned vehicles. However, the measured values of low and medium cost MEMS triaxial gyroscopes are mainly affected by temperature (or thermal effect) and random errors. As results, the drift errors correlated with temperature will reduce application accuracy of MEMS triaxial gyroscope. The traditional calibration method for thermal drift errors relies on the expensive equipment, such as turntable and the temperature control system, which increases the cost of calibration. Therefore, an effective thermal calibration method that is available when using low- or high-cost tools for MEMS triaxial gyroscope will be meaningful for majority users. Hence, this paper analyzed and established the thermal drift model of MEMS triaxial gyroscope, and proposed a segmented systematic calibration method based on 24 states according to this model. Simulation shows that the proposed method can obtain the results approaching the real parameter thermal drift curves. Calibration experiments and parameters test show that the max errors of attitude calculation are reduced to 10% of the results using the original parameters, which indicates that the effectiveness of the proposed method.

InSAR-DEM Block Adjustment Model for Upcoming BIOMASS Mission: Considering Atmospheric Effects

The unique P-band synthetic aperture radar (SAR) instrument, BIOMASS, is scheduled for launch in 2024. This satellite will enhance the estimation of subcanopy topography, owing to its strong penetration and fully polarimetric observation capability. In order to conduct global-scale mapping of the subcanopy topography, it is crucial to calibrate systematic errors of different strips through interferometric SAR (InSAR) DEM (digital elevation model) block adjustment. Furthermore, the BIOMASS mission will operate in repeat-pass interferometric mode, facing the atmospheric delay errors introduced by changes in atmospheric conditions. However, the existing block adjustment methods aim to calibrate systematic errors in bistatic mode, which can avoid possible errors from atmospheric effects through interferometry. Therefore, there is still a lack of systematic error calibration methods under the interference of atmospheric effects. To address this issue, we propose a block adjustment model considering atmospheric effects. Our model begins by employing the sub-aperture decomposition technique to form forward-looking and backward-looking interferograms, then multi-resolution weighted correlation analysis based on sub-aperture interferograms (SA-MRWCA) is utilized to detect atmospheric delay errors. Subsequently, the block adjustment model considering atmospheric effects can be established based on the SA-MRWCA. Finally, we use robust Helmert variance component estimation (RHVCE) to build the posterior stochastic model to improve parameter estimation accuracy. Due to the lack of spaceborne P-band data, this paper utilized L-band Advanced Land Observing Satellite (ALOS)-1 PALSAR data, which is also long-wavelength, to emulate systematic error calibration of the BIOMASS mission. We chose climatically diverse inland regions of Asia and the coastal regions of South America to assess the model’s effectiveness. The results show that the proposed block adjustment model considering atmospheric effects improved accuracy by 72.2% in the inland test site, with root mean square error (RMSE) decreasing from 10.85 m to 3.02 m. Moreover, the accuracy in the coastal test site improved by 80.2%, with RMSE decreasing from 16.19 m to 3.22 m.

The industrial robot reducer testing instrument dynamic torsional moment measurement error calibration, based on the Bisquare curve fitting-improved Bayes particle swarm optimization-nonlinear echo state network (BCF-IBPSO-NESN) method.

Industrial robots are important components in the production and manufacturing industry. As a core component of the industrial robot, the industrial robot reducer plays a crucial role in the performance of the entire industrial robot. The error analysis and accuracy traceability of the industrial robot reducer testing instrument are of great significance in improving the quality of the precision reducer. Therefore, it is essential to calibrate the dynamic torsional moment measurement error of the instrument. The features of the dynamic torsional moment measurement error are analyzed in this paper. Based on these features, a new dynamic torsional moment measurement error calibration method is proposed based on the Bisquare curve fitting-improved Bayes particle swarm optimization-nonlinear echo state network (BCF-IBPSO-NESN) algorithm. The proposed method focuses on calibrating the dynamic torsional moment measurement error of the industrial robot reducers in real time. The experimental results show that the dynamic torsional moment measurement error of the input side torsional moment measurement module and the output side torsional moment measurement module can be reduced to ±0.05 Nm and ±1 Nm, respectively. The contribution of this paper is that the method calibrates the dynamic torsional moment measurement error. It supplies a guideline for calibrating the dynamic torsional moment measurement error of the instrument under any load.

A Stepwise Calibration Method for Successive Start-Up Errors of the Three-Axis Gyroscope Based on the Characteristics of Compass Heading Alignment Error

A Stepwise Calibration Method for Successive Start-Up Errors of the Three-Axis Gyroscope Based on the Characteristics of Compass Heading Alignment Error

Error Calibration Method of Null Correctors for Large-Aperture Aspherical Mirrors

Error Calibration Method of Null Correctors for Large-Aperture Aspherical Mirrors

Kinematic error model and non-uniform calibration method for heavy load multi-DOF envelope forming press

Multi-DOF envelope forming is a new continuous and local plastic forming process for manufacturing high performance complex components with thin wall and high rib used in the aerospace industry. To achieve the new process, this paper develops a new heavy load multi-DOF envelope forming press with parallel kinematic mechanism (PKM), which can achieve the multi-DOF motion of envelope die. However, owing to the large scale and heavy load characteristics of the press, the kinematic error (fabrication and installation error) of the press is relatively large, resulting in the increased motion error of envelope die. Therefore, it is necessary to establish a reasonable kinematic error model and a calibration method to provide an essential basis for the precision design and control of the new press. Firstly, the kinematic error model, in which the 114 kinematic errors and multi-DOF motion error of envelope die are unitedly expressed and calculated based on the small displacement screw theory, and error Jacobian matrix for the press are established. Then the kinematic error mechanism for the press is disclosed. It is found that the motion error of envelope die is mainly attributed to 10 positional errors among 114 kinematic errors. Moreover, all the six error components of motion error of envelope die are time-varying with position changing of envelope die, and the position distributions of the maximum six error components are non-uniform during one motion period of envelope die. Based on the above results, a new non-uniform kinematic error calibration method for the press is proposed. Finally, the kinematic error calibration experiments are conducted. It is shown that the prediction accuracy of motion error of envelope die with the proposed non-uniform kinematic error calibration method is significantly improved from 89.06% to 99.67% compared with the traditional uniform kinematic error calibration method, which verifies that the established kinematic error model and non-uniform calibration method for heavy load multi-DOF envelope forming press are reliable.

Research on measurement error calibration method of TDLAS oxygen concentration detection based on CFD and SVR

Tunable Diode Laser Absorption Spectroscopy (TDLAS) enables rapid online detection of gas concentrations through the absorption of spectral lines by gas molecules in the infrared spectral region. In order to solve the problem of hysteresis and large errors of the measured values relative to the true values when TDLAS detects gases with simultaneous changes in oxygen concentration and flow rate in real-time, the CFD simulation model of the absorption cell is established by Fluent. The relationship between the measured value of TDLAS and the actual concentration change under different flow conditions is analyzed by simulation data, and the support vector machine regression calibration model is established to reduce the measurement error. It successfully reduces the average error from 5.844% to 2.899%, which is a reduction of 50.7%. The average error is further reduced to 1.308% after a secondary calibration based on different starting concentrations. The method is suitable for concentration detection in the presence of rapid changes in oxygen concentration.

An offset and gain error calibration method in high-precision SAR ADCs

Successive approximation (SAR) ADC suffers from kinds of nonidealities such as offset and gain error which affect its absolute quantization range and reduce its performance in the high-precision applications. This paper presents a static offset and an embedded gain error calibration in analog domain, attempting to improve the conversion range error in SAR ADC architecture. The presented calibration technique reuses the CADC array, facilitating an analog-domain calibration within small dissipation.

A novel calibration method for kinematic parameter errors of industrial robot based on Levenberg–Marquard and Beetle Antennae Search algorithm

In this paper, a new kinematic parameter error calibration method based on the Levenberg–Marquard and the beetle antennae search algorithm is proposed to enhance the positioning accuracy of the industrial robot. Firstly, the Modified Denavit–Hartenberg model is chosen to establish the kinematic model for the industrial robot. Secondly, the kinematic parameter errors are calibrated by Levenberg–Marquard algorithm and then obtain the kinematic parameter errors of the industrial robot. Thirdly, these kinematic parameter errors are taken as the center values for the initial individual of the beetle antennae search algorithm. The kinematic parameter errors are accurately calibrated using the beetle antennae search algorithm to obtain the best value for the kinematic parameter errors. Finally, experimental verification results demonstrate that the positioning error of the industrial robot is decreased from 0.7332 mm to 0.1392 mm by using the proposed Levenberg–Marquard and beetle antennae search algorithm. The results also demonstrate that the proposed Levenberg–Marquard and beetle antennae search algorithm calibrate the kinematic parameter errors of the industrial robot effectively and enhance the positioning accuracy of the industrial robot significantly.

Geometric Error Calibration of XYZ-3RPS Hybrid Kinematic Machine via Binocular Vision

Abstract To improve the motion accuracy of an XYZ-3RPS hybrid kinematic machine (HKM), a geometric error calibration method via binocular vision measurement is studied. First, to separately calibrate the series kinematic mechanisms (SKMs) and parallel kinematic mechanisms (PKMs), the geometric error identification equations (GEIEs) of the XYZ SKM and 3RPS PKM are derived, respectively. By analyzing the different influence principles of the geometric errors on the position and attitude of the 3RPS PKM, a constraint function is added to the GEIE of the PKM to improve the calculation accuracy. Moreover, the geometric error compensation strategy is based on the structural characteristics of the XYZ-3RPS HKM. In addition, based on the principle of binocular vision measurement, two calibration plates, called dynamic and static calibration plates, are designed as markers to define the coordinate systems, enabling the acquisition of full positions and attitudes. Furthermore, a marker transformation method and an in-situ adjustment method are designed to determine the positions and attitudes of the HKM required for calibration such that the marker is always at the center of the field of view of the camera to improve measurement accuracy. Finally, the effectiveness of the calibration method is verified through prototype experiments.

On-orbit geometric calibration of satellite laser altimeters using infrared detectors and corner-cube retroreflectors

ABSTRACT After being launched into orbit, the geometric calibration of a satellite laser altimeter will reduce errors in laser pointing and ranging caused by satellite vibrations during launch, environmental changes, and thermal effects during long-term operation, which guarantees the accuracy of measurement data. In this study, a satellite laser geometric calibration method combining infrared detectors and corner-cube retroreflectors (CCRs) is proposed. First, a CCR-based laser ranging error calibration method was established, and then a laser pointing error calibration model was derived based on a single infrared detector array. Taking GaoFen-7 (GF-7) satellite laser beam 2 as the experimental object, laser geometric calibration was realized using an infrared detector and CCR-measured data. Then, the accuracy of the proposed method was compared with that of other calibration methods, the CMLID and the CMSPR. The results show that the accuracy of the proposed calibration method is equivalent to that of the CMLID and higher than that of the CMSPR. Among them, the accuracy of the laser pointing after calibration using the proposed method is better than 0.8 arcsec, and the elevation accuracy of the laser on flat, sloping, and mountainous terrains is better than 0.11 m, 0.30 m, and 1.80 m, respectively.

An Installation Angle Error Calibration Method in an Ultra-Short Baseline System Based on a Dual Transponder

Abstract The installation error of an acoustic transceiver array is one of the important error sources in an ultra-short baseline (USBL) system. In a USBL system with a positioning accuracy of 0.5%, an installation error angle of 1° will lead to a positioning error of 1.7% times the slant distance. In this paper, a dual transponder-based installation angle error calibration method for USBL is proposed. First, the positioning errors induced by various installation angles are deduced and analysed using the linear measurement of seafloor targets. Then, an iterative algorithm is proposed that estimates the rolling alignment error, pitching alignment error, and heading alignment error, in that order. The simulation and experienced results show that, after three iterations, the estimates of the three alignment errors can converge quickly, all of the estimates converge to within 0.001° and the estimated values are very close to the true values. The horizontal positioning error caused by the installation error angle can be reduced by nearly 75%. The method has good effectiveness and robustness, and can greatly improve the positioning accuracy of the USBL system.

MEMS-IMU automatic calibration system design and implementation

Aiming at the problems of traditional calibration, long calibration cycles, and low efficiency of traditional error calibration methods for MEMS inertial devices, a MEMS IMU automatic calibration system is proposed. Firstly, the error mechanism of MEMS-IMU is analyzed, the error model is established, and the calibration scheme is designed. Then, the automatic control of the turntable and the automatic data acquisition of MEMS inertial devices are realized by designing the data interaction mechanism between the system equipment. Finally, the least square method is used to identify the model parameters. The experimental results show that this method can meet the requirements of multi-position and multi-rate calibration. After compensation, the relative errors of the MEMS gyroscope and accelerometer are 0.04% and 0.15%, respectively, and the cross-coupling error of the MEMS gyroscope is reduced to about 0.1 °/s. At the same time, the whole calibration process is easy to operate, which greatly shortens the calibration time and improves the calibration efficiency.

Error calibration method for a vortex retarder based spatially modulated polarimeter

Error calibration method for a vortex retarder based spatially modulated polarimeter

Fast Error Calibration for Three-Axis SQUID Magnetometers Based on Full-Space Rotational and Frequency-Controllable Magnetic Field

In order to overcome the limitations of the traditional error calibration method for three-axis superconducting quantum interference device (SQUID) magnetometers, this article presents a fast error calibration method for three-axis SQUID magnetometers. In the proposed method, a full-space rotational and frequency-controllable magnetic field with constant total field intensity can be generated by a triaxial Helmholtz coil. Meanwhile, the nonorthogonal error, zero offset error, and proportional coefficient error of the three-axis SQUID magnetometers, which measure the relative value rather than the absolute value, can be accurately solved by an error modeling and ellipsoid fitting theory. Compared with the traditional scalar calibration method, this method replaces the rotation of Dewar and three-axis SQUID magnetometers with a rotating magnetic field, thus avoiding the interference and influence of motion. Compared with the traditional vector calibration method, this method does not need to ensure the alignment between the three-axis SQUID magnetometers and triaxial Helmholtz coil. Moreover, the interference of low-frequency magnetic field can be suppressed by shortening the period of rotating magnetic field. Simulation and experiments prove the effectiveness of this method. After calibration by the proposed method, the root-mean-square error is reduced to 0.414 from 138.411 nT in the electromagnetic shielding room. Repetitive and comparative experiments with the traditional method in field also prove the superiority and stability of the proposed method.

Error Calibration for Crosstalk of SQUIDs in Full Tensor Magnetic Gradiometer Based on Moore–Penrose Inverse and Helmholtz Coil

In order to calibrate crosstalk error between superconducting quantum interference device (SQUID) magnetometers in a multichannel SQUID system, we propose an innovative error calibration method for crosstalk of SQUID magnetometers based on the Moore–Penrose inverse method and Helmholtz coil in this article and successfully apply it to an eight-channel SQUID magnetometers based full tensor magnetic gradiometer (FTMG). We first analyze the causes of crosstalk through working principle of the SQUID readout circuit and build the crosstalk error model of the eight-channel FTMG. Then, we introduce the solution method of 56 crosstalk coefficients based on the Moore–Penrose inverse method and the construction method of matrix needed for solution based on Helmholtz coil. The effect of nonuniformity of Helmholtz coil on the calibration of crosstalk is analyzed and calculated. The effectiveness of the proposed method is proved by repetitive simulation and comparative experiments. Compared with the traditional direct measurement method, this method has the advantage of high efficiency, and the more the channels of SQUID, the more obvious is the superiority.

Research on A Gyro Error Calibration Method Based on Dynamic Compensation

Gyroscopes in Micro-Electro-Mechanical Systems (MEMS) technology have high accuracy, convenient use, and broad application prospects. In practical applications, it is found that angular rate error is one of the main reasons that affect the output accuracy of gyroscopes. In the angular rate error calibration of MEMS gyroscopes, the method of calibrating the gyroscopes only by changing the bias and scale coefficients obtained by fitting cannot meet the angular rate error calibration of MEMS gyroscopes whose dynamic range exceeds . Therefore, the research proposes an improved calibration method to solve the problem of angular rate error, using dynamic compensation algorithms to achieve dynamic compensation for the angular rate of MEMS gyroscopes. Experiments show that using the dynamic compensation calibration method proposed in this paper, the root mean square error of the angular rate of MEMS gyroscopes has decreased by 52.37% compared to the previous one, verifying the feasibility of this method.

Modeling and digital calibration for the mirror normal pointing error of the 2D scanning reflector.

The 2D scanning reflector (2DSR) has been widely used in various important opto-mechanical systems. The pointing error of the mirror normal of the 2DSR will greatly affect the optical axis pointing accuracy. In this work, a digital calibration method for the pointing error of the mirror normal of the 2DSR is researched and verified. At first, the error calibration method is proposed based on the datum, which consists of a high-precision two-axis turntable and the photoelectric autocollimator. All the error sources, including the assembly errors and the datum errors in the calibration are analyzed comprehensively. Then the pointing models of the mirror normal are derived from the 2DSR path and the datum path by using the quaternion mathematical method. Additionally, the pointing models are linearized by the Taylor series first-order approximation of the error parameter trigonometric function items. The solution model of the error parameters is further established by using the least square fitting method. In addition, the procedure of the datum establishment is introduced in detail to strictly control the datum error to be small enough, and the calibration experiment is carried out subsequently. At last, the errors of the 2DSR are calibrated and discussed. The results show that the pointing error of the mirror normal of the 2DSR decreases from 365.68 to 6.46 arc seconds after the error compensation. The consistency of the error parameters of the 2DSR calibrated by digital calibration and physical calibration verifies the effectiveness of the digital calibration method proposed in this paper.

Development of personal comfort model and its use in the control of air conditioner

The accurate identification of the real-time thermal state of personnel working indoors has been the focus of researchers. In this study, a detailed examination of the entire process of developing a personal comfort model, from theory to practice, is conducted. In particular, the subject of this investigation is a smart air conditioner capable of predicting thermal sensation based on an infrared (IR) sensor that measures the skin temperature of personnel and then implements automatic control. Random forest algorithm was employed to establish a thermal sensation prediction model, which accepts skin and air temperatures as input parameters. The model achieves a high prediction accuracy value of 0.84. Given the measurement errors of low-cost IR sensors, a simulated temperature measurement experiment based on the manikin was conducted, and an error calibration method based on multiple linear regression was developed through the experiment. 30 subjects participated in another prototype test experiment, which proved that the air conditioner can accomplish effective automatic control based on the prediction of thermal sensation, avoid the occurrence of extreme temperatures, and ensure the thermal comfort of personnel. The possible causes of remaining problems and potential improvement schemes are discussed in detail.

Analysis and Compensation of Bias Drift of Force-to-Rebalanced Micro-Hemispherical Resonator Gyroscope Caused by Assembly Eccentricity Error

Aiming at the excitation coupling error caused by assembly eccentricity error in micro-hemispherical resonator gyroscope ( <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\mu $ </tex-math></inline-formula> HRG), this paper proposes a method to identify excitation coupling coefficients by using the relationship between input angular velocity and excitation forces during mode reverses. Firstly, this paper studies the influence mechanism of eccentricity error on displacement detection and electrostatic excitation under force-to-rebalanced (FTR) mode. Furthermore, theoretical derivation and simulation results show that the coupling error of excitation force will lead to the mutual coupling between the driving and the sensing loops, which reduces the stability of the driving force and introduces additional zero-bias drift into the sensing mode. According to the proposed identification method of the coupling coefficient of excitation force, the coupling coefficients are calibrated, and the principle of direct compensation in the FPGA system is given. The experimental results show that in the FTR mode, the driving force amplitudes at different input angular rates and the zero-bias drift at room temperature before and after error compensation are compared, which verifies the effectiveness of the proposed error calibration and compensation method. At room temperature, under the FTR mode, compared with the uncompensated test results, the average value of the measured bias stability ( <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$1\sigma $ </tex-math></inline-formula> ) of the three groups is reduced from 74.667 °/h to 9.670°/h, which is improved by nearly 7.72 times. When at 40°C, the <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\mu $ </tex-math></inline-formula> HRG’s bias stability ( <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$1\sigma $ </tex-math></inline-formula> ) is reduced from uncompensated 177.151°/h to compensated 9.256°/h. [2022-0174]