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Time-varying baseline error correction method for ground-based micro-deformation monitoring radar

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Journal of Systems Engineering and Electronics 2022年第4期33卷 938-950页

作者： LEI Tianjie WANG Jiabao HUANG Pingping TAN Weixian QI Yaolong XU Wei ZHAO Chun China Institute of Water Resources and Hydropower Research Beijing 100038China Institute of Environment and Sustain-able Development in Agriculture Chinese Academy of Agricultural SciencesBeijing 100083China College of Geoscience and Surveying Engineering China University of Mining and TechnologyBeijing 100098China College of Information Engineering Inner Mongolia University of TechnologyHohhot 010051China Inner Mongolia Key Laboratory of Radar Technology and Application Hohhot 010051China

In recent years, ground-based micro-deformation monitoring radar has attracted much attention due to its excellent monitoring capability. By controlling the repeated campaigns of the radar antenna on a fixed track, ground-based micro-deformation monitoring radar can accomplish repeat-pass interferometry without a space baseline and thus obtain highprecision deformation data of a large scene at one time. However, it is difficult to guarantee absolute stable installation position in every campaign. If the installation position is unstable, the stability of the radar track will be affected randomly, resulting in time-varying baseline error. In this study, a correction method for this error is developed by analyzing the error distribution law while the spatial baseline is unknown. In practice, the error data are first identified by frequency components, then the data of each one-dimensional array(in azimuth direction or range direction) are grouped based on numerical distribution period, and finally the error is corrected by the nonlinear model established with each group.This method is verified with measured data from a slope in southern China, and the results show that the method can effectively correct the time-varying baseline error caused by rail instability and effectively improve the monitoring data accuracy of groundbased micro-deformation radar in short term and long term.

关键词： ground-based micro-deformation monitoring radar deformation monitoring time-varying baseline error compensation

error modeling and compensating of a novel 6-DOF aeroengine rotor docking equipment

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Chinese Journal of Aeronautics 2022年第6期35卷 312-324页

作者： Tianyi ZHOU Hang GAO Xuanping WANG Lun LI Qing LIU Key Laboratory for Precision and Non-traditional Machining Technology of Ministry of Education Dalian University of TechnologyDalian 116024China AECC Shenyang Liming Aero-engine Co. LtdChina

In the docking process of aeroengine rotor parts,docking accuracy that indicates the gaps between the end faces is strictly required.A key issue is improving docking accuracy using automated docking equipment.In this paper,a systematic study is carried out on the error modeling and compensation of a novel six-degrees-of-freedom(6-DOF)docking equipment for aeroengine rotors.First,a new model for indicating the main indexes of docking accuracy is proposed.Then,the error model of a specially designed 6-DOF docking equipment is established based on a modified Denavit Hartenberg method with five parameters.Subsequently,two error compensation methods are proposed.Based on the above models,a docking accuracy simulation algorithm is proposed using the Monte Carlo method.Finally,verification experiments are conducted.The results show that,for the maximum values and standard deviations of the gaps between the rotor end-faces in the actual and target positions and attitudes,i.e.,main indexes that represent docking accuracy,the deviation rates between the simulation and experimental results are less than20%.The modeling methods have referential significance.The decline rates of these values are 50–65%when using the two proposed compensation methods.The compensation methods significantly improve the docking accuracy.

关键词： Accuracy analysis Aeroengine rotor Docking error compensation error models Multi-degree-of-freedom structures

A 130 nm CMOS low-power SAR ADC for wide-band communication systems

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Journal of Semiconductors 2014年第2期35卷 112-119页

作者：边程浩颜俊石寅孙玲 Institute of Semiconductors Chinese Academy of Sciences Jiangsu Key Laboratory of ASIC Design Nantong University

This paper presents a low power 9-bit 80 MS/s SAR ADC with comparator-sharing technique in 130 nm CMOS process. Compared to the conventional SAR ADC, the sampling phase is removed to reach the full efficiency of the comparator. Thus the conversion rate increases by about 20% and its sampling time is relaxed. The design does not use any static components to achieve a widely scalable conversion rate with a constant FOM. The floorplan of the capacitor network is custom-designed to suppress the gain mismatch between the two DACs. The ＇set-and- down＇ switching procedure and a novel binary-search error compensation scheme are utilized to further speed up the SA bit-cycling operation. A very fast logic controller is proposed with a delay time of only 90 ps. At 1.2 V supply and 80 MS/s the ADC achieves an SNDR of 51.4 dB and consumes 1.86 mW, resulting in an FOM of 76.6 fJ/conversion-step. The ADC core occupies an active area of only 0.089 mm2.

关键词： ADC SAR capacitor-sharing error compensation capacitor array dynamic logic

Observer-based backstepping longitudinal control for carrier-based UAV with actuator faults

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Journal of Systems Engineering and Electronics 2017年第2期28卷 322-337页

作者： Fengying Zheng Ziyang Zhen Huajun Gong College of Astronautics Nanjing University of Aeronautics and Astronautics Nanjing 210016 China College of Automation Engineering Nanjing University of Aeronautics and Astronautics Nanjing 210016 China

The paper presents the longitudinal control for the carrier-based unmanned aerial vehicle (UAV) system with unmeasured states, actuator faults, control input constraints, and external disturbances. By combining output state observer, adaptive fuzzy control, and constraint backstepping technology, a robust fault tolerant control approach is proposed. An output state observer with fuzzy logic systems is developed to estimate unmeasured states, and command filters rather than differentiations of virtual control law are used to solve the computational complexity problem in traditional backstepping. Additionally, a robust term is introduced to offset the fuzzy adaptive estimation error and external disturbance, and an appropriate fault controller structure with matching conditions obtained from fault compensation is proposed. Based on the Lyapunov theory, the designed control program is illustrated to guarantee that all the closed-loop signals of the given system are bounded, and the output errors converge to a small neighborhood of zero. A carrier-based UAV nonlinear longitudinal model is employed to testify the feasibility and validity of the control scheme. The simulation results show that all the controllers can perform at a satisfactory level of reference tracking despite the existence of unknown aerodynamic parameters and actuator faults. ? 2017 Beijing Institute of Aerospace Information.

关键词： Actuators Aircraft control Backstepping Control system analysis Control theory Controllers error compensation Fault tolerance Flight control systems Fuzzy control Fuzzy filters Fuzzy logic State estimation Three term control systems Unmanned aerial vehicles (UAV)

Modeling and compensation Technology for the Comprehensive errors of Fixture System

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Chinese Journal of Mechanical Engineering 2012年第2期25卷 385-391页

作者： HE Gaiyun YANG Baolong DING Baihui JIA Hongyang College of Mechanical Engineering Tianjin UniversityTianjin 300072China

error modelling and compensating technology is an effective method to improve the processing precision.The position and orientation deviation of workpiece is caused by the fixing and manufacturing errors of the fixture.How to reduce the position and orientation deviation of workpiece has become a technical problem of improving the processing quality of workpiece.In order to increase machining accuracy,an implementation scheme of fixture system comprehensive errors（FSCE） compensation is proposed.A FSCE parameter model is established by analyzing the influence of contact points on the position and orientation of workpiece.Meanwhile,a parameter identification method for FSCE parameter model is presented by using the 3-2-1 deterministic positioning fixture,which determines the model parameters.Moreover,a FSCE compensation model is formulated to study the compensation value of the cutting position.By using RenishawOMP60 Probe and combining vertical machining centre（SKVH850） equipment with SKY2001 Open CNC System,on-machine verification system（OMVS） is built to measure FSCE successfully.The processing error can be reduced by analyzing the cutting position of the tool with the homogeneous transformation of space coordinate system.Finally,the compensation experiment of real time errors is conducted,and the cylindricality and perpendicularity errors of hole surface are reduced by 30.77% and 28.57%,respectively.This paper provides a new way of realizing the compensation of FCSE,which can improve the machining accuracy of workpiece largely.

关键词： fixture system error compensation on-machine verification the position and orientation deviation machining accuracy

Determination of optimal samples for robot calibration based on error similarity

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Chinese Journal of Aeronautics 2015年第3期28卷 946-953页

作者： Tian Wei Mei Dongqi Li Pengcheng Zeng Yuanfan Hong Peng Zhou Wei College of Mechanical and Electronical Engineering Nanjing University of Aeronautics and Astronautics

Abstract Industrial robots are used for automatic drilling and riveting. The absolute position accuracy of an industrial robot is one of the key performance indexes in aircraft assembly, and can be improved through error compensation to meet aircraft assembly requirements. The achiev- able accuracy and the difficulty of accuracy compensation implementation are closely related to the choice of sampling points. Therefore, based on the error similarity error compensation method, a method for choosing sampling points on a uniform grid is proposed. A simulation is conducted to analyze the influence of the sample point locations on error compensation. In addition, the grid steps of the sampling points are optimized using a statistical analysis method. The method is used to generate grids and optimize the grid steps of a Kuka KR-210 robot. The experimental results show that the method for planning sampling data can be used to effectively optimize the sampling grid. After error compensation, the position accuracy of the robot meels the position accuracy require- ments.

关键词： Aircraft assembly error compensation Positioning accuracy Robotics Sampling grid

Autofocus technique for ISAR imaging of uniformly rotating targets based on the ExCoV method

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Journal of Systems Engineering and Electronics 2017年第2期28卷 267-275页

作者： Chengguang Wu Hongqiang Wang Bin Deng Yuliang Qin Wuge Su Institute of Space Electronic Technology School of Electronic Science and EngineeringNational University of Defense Technology Changsha 410073 China

The inverse synthetic aperture radar (ISAR) imaging can be converted into a sparse reconstruction problem and solved by the l1norm minimization algorithm. The basis matrix in sparse ISAR imaging is usually characterized by the unknown rotation rate of a moving target, thus the rotation rate and the sparse signal should be jointly estimated. Especially due to the imperfect coarse motion compensation, we consider the phase error correction problem in the context of the sparse signal reconstruction. To address this issue, we propose an iterative reweighted method, which jointly estimates the rotation rate, corrects the phase error and reconstructs a high resolution ISAR image. The proposed method gives a gradual and interweaved iterative process to refine the unknown parameters to achieve the best sparse representation for the ISAR signals. Particularly, in ISAR image reconstruction, the l1norm minimization algorithm is sensitive to user parameters. Setting these user parameters are not trivial and the reconstruction performance depends significantly on their choices. Then, we consider an expansion-compression variance-component (ExCoV) based method, which is automatic and demands no prior knowledge about signal-sparsity or measurement-noise levels. Both numerical and electromagnetic data experiments are implemented to show the effectiveness of the proposed method. It is shown that the proposed method can estimate the rotation rate and correct the phase errors simultaneously, and its superior performance is proved in terms of high resolution ISAR image. ? 2017 Beijing Institute of Aerospace Information.

关键词： error compensation error correction errors Image processing Image reconstruction Inverse problems Inverse synthetic aperture radar Iterative methods Motion compensation Numerical methods Rotation Signal reconstruction Synthetic aperture radar

A D-optimal Multi-position Calibration Method for Dynamically Tuned Gyroscopes

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Chinese Journal of Aeronautics 2011年第2期24卷 210-218页

作者： FU Li ZHU Yongquan WANG Lingling WANG Xinling School of Automation Science and Electrical Engineering Beihang University Beijing 100191 China

This paper presents a novel experimental design to greatly improve the calibration accuracy of the acceleration-insensitive bias and the acceleration-sensitive bias of the dynamically tuned gyroscopes（DTGs）.In order to reduce experimental cost,the D-optimal criteria with constraints are constructed.The turntable positions and the number of test points are chosen to build D-optimal experimental designs.The D-optimal experimental designs are tested by multi-position calibration experiment for tactical-grade DTGs.Test results show that,with the same cost,the fit uncertainty is reduced by about 50% by using the D-optimal 8-position experimental procedure,compared to using a defacto standard experimental procedure in ANSI/IEEE Std 813-1988.Furthermore,the new experimental procedure almost achieves optimal accuracy with only 12-position which is half the cost of the widely adopted 24-position experimental procedure for achieving optimal accuracy.

关键词： optimization methods calibration gyroscopes error compensation design for testability

Effects of Comprehensive Eccentricity of Involute Cam on Gear Profile Deviations

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Chinese Journal of Mechanical Engineering 2011年第3期24卷 392-398页

作者： WANG Liding LING Siying MAYong WANG Xiaodong LOU Zhifeng Key Laboratory for Precision ＆ Non-traditional and Micro System Machining of Ministry of Education Dalian University of Technology Dalian 116023 China Key Laboratory for Micro/Nano Technology and System of Liaoning Province Dalian University of Technology Dalian 116023 China

The manufacturing accuracy of ultra-precision master gears signifies the technological capability of the ultra-precision gear.Currently,there is little report about the manufacturing technologies of ultra-precision master gears at home and aboard.In order to meet the requirement of grinding ultra precision master gear,the gear grinder with flat-faced wheel Y7125 is chosen as the object machine tool and the geometric model of its precision generating part,the involute cam,is established.According to the structure of the involute cam,the effective working section and its adjustable range of the cam are determined,and the mathematical expressions of the effects of comprehensive eccentricity of the involute cam on gear profile deviations are derived.According to the primary harmonic trends of the deviation curve,it is shown that gear profile form and slope deviations in different work generating sections of the involute cam are different which the latter changes with the cam eccentricity obviously.Then,the issues of extreme values and methods of error compensation are studied and the conclusion that large adjustable range is benefit to search the optimal involute-cam section which is responding to the minimum gear profile deviations is obtained.A group of examples are calculated by choosing master gears with d=120 mm and m=2-6 mm and an involute cam with base diameter djcam =117 mm.And it is found that the maximum gear profile deviation counts for no more than 5% of the cam eccentricity after error compensation.A gear-grinding experiment on the master gear with m=2 mm is conducted by choosing different sections of the involute cam and the differences of gear profile deviations then the existence of the cam eccentricity are verified.The research discloses the rule of gear profile deviations caused by the comprehensive eccentricity of the involute cam and provides the theoretical guidance and the processing methods for grinding profile of the ultra precision master gear.

关键词： gear grinder with flat-faced wheel involute cam ultra precision master gear gear profile deviations error compensation