Iterative Learning Control with Extended State Observer for Telescope System

Cai, Huaxiang; Huang, Yongmei; Du, Junwei; Tang, Tao; Zuo, Dan; Li, Jinying

doi:10.1155/2015/701510

Cited by 10 publications

(6 citation statements)

References 25 publications

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“…For example, in medical ultrasound B-scans, this step helps to reject the small echoes from backscattering that blur the tissue interface and reduce the image contrast [41,42]. In the automatic inspection of pipes, the noise reduction step helps to detect small thick-walled pipe defects; because the amplitude of the echo signals drowns in the noise, this affects the extraction of the defect signal and its position [43]. For the first step (noise reduction), we used a finite impulse response (FIR) bandpass filter.…”

Section: Methodsmentioning

confidence: 99%

Design and Validation of an Articulated Sensor Carrier to Improve the Automatic Pipeline Inspection

MARTINEZ

Rodríguez-Olivares

Torres-Torres

et al. 2019

Sensors

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Pipeline inspection gauges (PIGs) carry out automatic pipeline inspection with nondestructive testing (NDT) technologies like ultrasound, magnetic flux leakage, and eddy current. The ultrasonic straight beam allows technicians to determine the wall thickness of the pipeline through the time of flight diffraction (TOFD), providing the pipeline reconstruction and allowing the detection of several defects like dents or corrosion. If the pipeline is of a long distance, then the inspection process is automatic, and the fluid pressure pushes the PIG through the pipeline system. In this case, the PIG velocity and its axial alignment with the pipeline cannot be controlled. The PIG geometry, the pipeline deformations, and the girth welds cause a continuous chattering when the PIG is running, removing the transducers perpendicularity with the inspection points, which means that some echoes cannot be received. To reduce this problem, we propose a novel method to design a sensor carrier that takes into account the angularity and distance effects to acquire the straight beam echoes. The main advantage of our sensor carrier is that it can be used in concave and convex pipeline sections through geometric adjustments, which ensure that it is in contact with the inner pipe wall. Our improvement of the method is the characterization of the misalignment between the internal wall of the pipeline and the transducer. Later, we analyzed the conditions of the automatic pipeline inspection, the existing recommendations in state-of-the-art technology, and the different mechanical scenarios that may occur. For the mechanical design, we developed all the equations and rules. At the signal processing level, we set a fixed gain in the filtering step to obtain the echoes in a defined distance range without saturating the acquisition channels. For the validation, we compared through the mean squared error (MSE) our sensor carrier in a straight pipe section and a pipe elbow of steel versus other sensor carrier configurations. Finally, we present the design parameters for the development of the sensor carrier for different pipeline diameters.

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Section: Methodsmentioning

confidence: 99%

Design and Validation of an Articulated Sensor Carrier to Improve the Automatic Pipeline Inspection

MARTINEZ

Rodríguez-Olivares

Torres-Torres

et al. 2019

Sensors

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“…Using Lemma 1 and multiplying both sides of the above inequality (14) by − and taking the -norm, we have…”

Section: Proof It Is Easy To Know That For Anymentioning

confidence: 99%

“…Iterative learning control, which belongs to the intelligent control methodology, is an approach for fully utilizing the previous control information and improving the transient performance of studied systems that is suitable for repetitive movements. Its goal is to achieve full range of tracking tasks on finite interval (see [2][3][4][5][6][7][8][9][10][11][12][13][14]).…”

Section: Introductionmentioning

confidence: 99%

The Effect of Initial State Error for Nonlinear Systems with Delay via Iterative Learning Control

Qunli

2016

Advances in Mathematical Physics

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An iterative learning control problem for nonlinear systems with delays is studied in detail in this paper. By introducing theλ-norm and being inspired by retarded Gronwall-like inequality, the novel sufficient conditions for robust convergence of the tracking error, whose initial states are not zero, with time delays are obtained. Finally, simulation example is given to illustrate the effectiveness of the proposed method.

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“…Iterative learning control methodology, which is proposed by Arimoto et al in 1984 (See [1]), is to utilize the previous control information of the studied systems. The repetitive behavior has been a major research area and a hot issue in recent years (See [2][3][4][5][6][7][8][9][10][11][12][13][14][15]).…”

Section: Introductionmentioning

confidence: 99%