scholarly journals Identification of Random Dynamic Force Using an Improved Maximum Entropy Regularization Combined with a Novel Conjugate Gradient

2017 ◽  
Vol 2017 ◽  
pp. 1-14 ◽  
Author(s):  
ChunPing Ren ◽  
NengJian Wang ◽  
ChunSheng Liu
Keyword(s):  
Maximum Entropy ◽  
Conjugate Gradient ◽  
Regularization Parameter ◽  
Engineering Application ◽  
Optimal Solution ◽  
Identification Problem ◽  
Dynamic Force ◽  
Force Identification ◽  
Mathematical Algorithm ◽  
Practical Engineering

We propose a novel mathematical algorithm to offer a solution for the inverse random dynamic force identification in practical engineering. Dealing with the random dynamic force identification problem using the proposed algorithm, an improved maximum entropy (IME) regularization technique is transformed into an unconstrained optimization problem, and a novel conjugate gradient (NCG) method was applied to solve the objective function, which was abbreviated as IME-NCG algorithm. The result of IME-NCG algorithm is compared with that of ME, ME-CG, ME-NCG, and IME-CG algorithm; it is found that IME-NCG algorithm is available for identifying the random dynamic force due to smaller root mean-square-error (RMSE), lower restoration time, and fewer iterative steps. Example of engineering application shows that L-curve method is introduced which is better than Generalized Cross Validation (GCV) method and is applied to select regularization parameter; thus the proposed algorithm can be helpful to alleviate the ill-conditioned problem in identification of dynamic force and to acquire an optimal solution of inverse problem in practical engineering.

scholarly journals A Novel Method of Dynamic Force Identification and Its Application

2019 ◽  
Vol 2019 ◽  
pp. 1-10 ◽  
Author(s):  
Nengjian Wang ◽  
Qinhui Liu ◽  
Chunping Ren ◽  
Chunsheng Liu
Keyword(s):  
Conjugate Gradient ◽  
Optimization Problems ◽  
Stability And Convergence ◽  
Future Research ◽  
Dynamic Force ◽  
Force Identification ◽  
Unconstrained Optimization Problems ◽  
Practical Engineering ◽  
Gradient Parameter ◽  
Spectral Conjugate Gradient

In this paper, an efficient mixed spectral conjugate gradient (EMSCG, for short) method is presented for solving unconstrained optimization problems. In this work, we construct a novel formula performed by using a conjugate gradient parameter which takes into account the advantages of Fletcher–Reeves (FR), Polak–Ribiere–Polyak (PRP), and a variant Polak-Ribiere-Polyak (VPRP), prove its stability and convergence, and apply it to the dynamic force identification of practical engineering structure. The analysis results show that the present method has higher efficiency, stronger robust convergence quality, and fewer iterations. In addition, the proposed method can provide more efficient and numerically stable approximation of the actual force, compared with the FR method, PRP method, and VPRP method. Therefore, we can make a clear conclusion that the proposed method in this paper can provide an effective optimization solution. Meanwhile, there is reason to believe that the proposed method can offer a reference for future research.

scholarly journals A Novel Fractional Tikhonov Regularization Coupled with an Improved Super-Memory Gradient Method and Application to Dynamic Force Identification Problems

2018 ◽  
Vol 2018 ◽  
pp. 1-16 ◽  
Author(s):  
Nengjian Wang ◽  
Chunping Ren ◽  
Chunsheng Liu
Keyword(s):  
Tikhonov Regularization ◽  
Present Method ◽  
Optimal Solution ◽  
Identification Problem ◽  
Dynamic Force ◽  
Inverse Identification ◽  
Identification Problems ◽  
Force Identification ◽  
New Findings ◽  
Ill Posed

This paper presents a novel inverse technique to provide a stable optimal solution for the ill-posed dynamic force identification problems. Due to ill-posedness of the inverse problems, conventional numerical approach for solutions results in arbitrarily large errors in solution. However, in the field of engineering mathematics, there are famous mathematical algorithms to tackle the ill-posed problem, which are known as regularization techniques. In the current study, a novel fractional Tikhonov regularization (NFTR) method is proposed to perform an effective inverse identification, then the smoothing functional of the ill-posed problem processed by the proposed method is regarded as an optimization problem, and finally a stable optimal solution is obtained by using an improved super-memory gradient (ISMG) method. The result of the present method is compared with that of the standard TR method and FTR method; new findings can be obtained; that is, the present method can improve accuracy and stability of the inverse identification problem, robustness is stronger, and the rate of convergence is faster. The applicability and efficiency of the present method in this paper are demonstrated through a mathematical example and an engineering example.

scholarly journals A Novel Improved Maximum Entropy Regularization Technique and Application to Identification of Dynamic Loads on the Coal Rock

2019 ◽  
Vol 2019 ◽  
pp. 1-12
Author(s):  
Chunsheng Liu ◽  
Chunping Ren
Keyword(s):  
Maximum Entropy ◽  
Dynamic Load ◽  
Regularization Parameter ◽  
Estimation Method ◽  
Identification Problem ◽  
Iteration Algorithm ◽  
Load Identification ◽  
Signal Processing Algorithm ◽  
Rock Structure ◽  
Coal Rock

A new signal processing algorithm was proposed to identify the dynamic load acting on the coal-rock structure. First, the identification model for dynamic load is established through the relationship between the uncertain load vector, and the assembly matrix of the responses was measured by the machinery dynamic system. Then, the entropy item of maximum entropy regularization (MER) is redesigned using the robust estimation method, and the elongated penalty function according to the ill-posedness characteristics of load identification, which was named as a novel improved maximum entropy regularization (IMER) technique, was proposed to process the dynamic load signals. Finally, the load identification problem is transformed into an unconstrained optimization problem and an improved Newton iteration algorithm was proposed to solve the objective function. The result of IMER technique is compared with MER technique, and it is found that IMER technique is available for analyzing the dynamic load signals due to higher signal-noise ratio, lower restoration time, and fewer iterative steps. Experiments were performed to investigate the effect on the performance of dynamic load signals identification by different regularization parameters and calculation parameters, pi, respectively. Experimental results show that the identified dynamic load signals are closed to the actual load signals using IMER technique combined with the proposed PSO-L regularization parameter selection method. Selecting optimal calculated parameters pi is helpful to overcome the ill-condition of dynamic load signals identification and to obtain the stable and approximate solutions of inverse problems in practical engineering. Meanwhile, the proposed IMER technique can also play a guiding role for the coal-rock interface identification.

scholarly journals Dynamic Force Identification Problem Based on a Novel Improved Tikhonov Regularization Method

2019 ◽  
Vol 2019 ◽  
pp. 1-13
Author(s):  
Chunping Ren ◽  
Nengjian Wang ◽  
Qinhui Liu ◽  
Chunsheng Liu
Keyword(s):  
Kernel Function ◽  
Tikhonov Regularization ◽  
Regularization Method ◽  
Integral Form ◽  
Identification Problem ◽  
Tikhonov Regularization Method ◽  
Dynamic Force ◽  
Conical Pick ◽  
Force Identification ◽  
Green Kernel

The main purpose of this paper is to identify the dynamic forces between the conical pick and the coal-seam. According to the theory of time domain method, the dynamic force identification problem of the system is established. The direct problem is described by Green kernel function method. The dynamic force is expressed by a series of functions superposed by impulses, and the dynamic response of the structure is expressed as a convolution integral form between the input dynamic force and the response of Green kernel function. Because of the ill-conditioned characteristics of the structure matrix and the influence of measurement noise in the process of dynamic force identification, it is difficult to deal with this problem by the usual numerical method. In present content, a novel improved Tikhonov regularization method is proposed to solve ill-posed problems. An engineering example shows that the proposed method is effective and can obtain stable approximate solutions to meet the engineering requirements.

scholarly journals Pose Determination of the Disc Cutter Holder of Shield Machine Based on Monocular Vision

Sensors ◽  
2022 ◽  
Vol 22 (2) ◽  
pp. 467
Author(s):  
Dandan Peng ◽  
Guoli Zhu ◽  
Dailin Zhang ◽  
Zhe Xie ◽  
Rui Liu ◽  
...  
Keyword(s):  
Measurement Method ◽  
Vision System ◽  
Engineering Application ◽  
Optimal Solution ◽  
Maximum Error ◽  
Vital Role ◽  
Disc Cutter ◽  
Accuracy Requirement ◽  
Practical Engineering ◽  
Shield Machine

The visual measurement system plays a vital role in the disc cutter changing robot of the shield machine, and its accuracy directly determines the success rate of the disc cutter grasping. However, the actual industrial environment with strong noise brings a great challenge to the pose measurement methods. The existing methods are difficult to meet the required accuracy of pose measurement based on machine vision under the disc cutter changing conditions. To solve this problem, we propose a monocular visual pose measurement method consisting of the high precision optimal solution to the PnP problem (OPnP) method and the highly robust distance matching (DM) method. First, the OPnP method is used to calculate the rough pose of the shield machine’s cutter holder, and then the DM method is used to measure its pose accurately. Simulation results show that the proposed monocular measurement method has better accuracy and robustness than the several mainstream PnP methods. The experimental results also show that the maximum error of the proposed method is 0.28° in the direction of rotation and 0.32 mm in the direction of translation, which can meet the measurement accuracy requirement of the vision system of the disc cutter changing robot in practical engineering application.

Dynamic Characteristics and Stability Analysis of Two-Dimensional (2D) Electro-Hydraulic Proportional Directional Valve

2015 ◽  
Author(s):  
S. Li ◽  
J. Ruan ◽  
B. Meng ◽  
W. A. Jia ◽  
H. Y. Xie
Keyword(s):  
Dynamic Characteristics ◽  
Magnetic Force ◽  
Engineering Application ◽  
Proportional Valve ◽  
Acceptable Range ◽  
Hydrostatic Force ◽  
Practical Engineering ◽  
Direct Operation ◽  
Electrohydraulic Valve ◽  
Proportional Directional Valve

A 2D electrohydraulic proportional directional valve is proposed, which integrates both direct and pilot operation of the valve. In this valve, the output magnetic force of the proportional solenoid is converted to rotate the spool through a thrust-torsion coupling and thus the pressure in the valve sensitive chamber is varied. The varied pressure exerted on the areas of the spool end produces a hydrostatic force to move the spool linearly, which will rotate the spool reversely. Theoretical analysis is carried to the proposed valve and the effects of the key geometric parameters on the dynamic characteristics of the 2D valve and stability are investigated. Experiments are also designed to access to the characteristics of the valve working under direct and pilot operation. The 2D electrohydraulic valve can work properly for both direct operation and pilot operation. The hysteresis and frequency response are measured and the results are within the acceptable range in practical engineering application required of the directional proportional valve.

A real time detection method for abnormal strapping of steel coil based on CCD active imaging

2021 ◽  
Author(s):  
Chuan Ye ◽  
Liming Zhao ◽  
Qiyan Wang ◽  
Bo Pan ◽  
Youchun Xie ◽  
...  
Keyword(s):  
Maximum Entropy ◽  
Detection Method ◽  
Saliency Detection ◽  
Automatic Segmentation ◽  
Engineering Application ◽  
Detection Accuracy ◽  
Steel Coil ◽  
Detection Model ◽  
Laser Stripe ◽  
Active Imaging

Abstract In order to accurately detect the abnormal looseness of strapping in the process of steel coil hoisting, an accurate detection method of strapping abnormality based on CCD structured light active imaging is proposed. Firstly, a maximum entropy laser stripe automatic segmentation model integrating multi-scale saliency features is constructed. With the help of saliency detection model, the purpose is to reduce the interference of the environment to the laser stripe and highlight the distinguishability between the stripe and the background. Then, the maximum entropy is used to segment the fused saliency features and accurately extract the stripe contour. Finally, the stripe normal field is obtained by calculating the stripe gradient vector, the stripe center line is extracted based on the stripe distribution normal direction, and the abnormal strapping is recognized online according to the stripe center. Experiments show that the proposed method is effective in terms of detection accuracy and time efficiency, and has certain engineering application value.

scholarly journals Experimental Study on Influence of Temperature to Control Performance for Viscoelastic Materials Pounding Tuned Mass Damper

2021 ◽  
Vol 8 ◽  
Author(s):  
Dehui Ye ◽  
Jie Tan ◽  
Yabin Liang ◽  
Qian Feng
Keyword(s):  
Engineering Application ◽  
Tuned Mass Damper ◽  
Frame Structure ◽  
Force Model ◽  
Viscoelastic Materials ◽  
Mass System ◽  
Mass Damper ◽  
Different Temperatures ◽  
Practical Engineering ◽  
Portal Frame Structure

The pounding tuned mass damper (PTMD) is a novel passive damper that absorbs and dissipates energy by an auxiliary tuned spring-mass system. Viscoelastic materials are attached to the interface of the limitation collar in the PTMD so that the energy dissipation capacity can be enhanced. Previous studies have successfully demonstrated the effectiveness of PTMD at room temperature. However, in practice, the PTMD may face a broad temperature range, which can affect the mechanical properties of the viscoelastic materials. Thus, the study of vibration control effectiveness of PTMD at different temperatures is of great significance for its practical engineering application. In this paper, a series of experiments were conducted to investigate the performance of a PTMD in a temperature-controlled environment. A PTMD device was designed to suppress the vibration of a portal frame structure and tested across environmental temperatures ranging from –20°C to 45°C. The displacement reduction ratios demonstrated the temperature robustness of the PTMD. Additionally, the numerical results validated the accuracy of the pounding force model and the performance of PTMD.

Study on Flexural Behavior of Pre-Stressed Concrete Hollow Slabs Strengthen with CFRP

2013 ◽  
Vol 446-447 ◽  
pp. 1413-1416
Author(s):  
Bo Wang ◽  
Juan Han
Keyword(s):  
Experimental Method ◽  
Engineering Application ◽  
Flexural Behavior ◽  
Experimental Basis ◽  
Concentrated Force ◽  
Disaster Area ◽  
Practical Engineering ◽  
Symmetrical Load

The purpose of this paper is to focus on studying its flexural behavior after different damages pre-stressed concrete hollow slab is strengthened with CFRP. By the experimental method, twelve residential pre-stressed concrete hollow slabs are tested under concentrated force at the two points of the symmetrical load in order to analyze both flexural behavior and effects factored by different bonding modes. The conclusion can be drawn that the flexural behavior of pre-stressed concrete hollow slabs strengthened with CFRP is well-tried. It provides design suggestions and reference for pre-stressed concrete hollow slabs strengthened with CFRP, and also provides an experimental basis for the repairing and reinforcing practical engineering application in Wenchuan disaster area.

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