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Prescribed Performance Control for Teleoperation System of Nonholonomic Constrained Mobile Manipulator Without Any approximation function

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IEEE TRANSACTIONS ON AUTOMATION SCIENCE AND ENGINEERING 2024年第3期21卷 2900-2911页

作者： Yang, Yana Yan, Yuwei Hua, Changchun Li, Junpeng Pang, Keli Yanshan Univ Inst Elect Engn Qinhuangdao 066004 Peoples R China

The teleoperation system of mobile manipulator has been widely applied for space exploration, medical assistance, and other fields. To improve operational efficiency, this paper presents a novel prescribed performance synchronization control scheme without applying any approximation functions for a class of teleoperation system of the mobile manipulator with time-varying delays and nonholonomic constraints. Compared with the general manipulator system, the mobile manipulator has a larger workspace and stronger operability. Yet, the heterogeneity of master-slave robots and the nonholonomic constraint of slave robot bring many difficulties to the control of the system. Firstly, a prescribed performance function (PPF) is designed to guarantee that the position synchronization errors are remained within the predetermined boundary and converge to a small preset area within a preset time. Then, the direct force feedback information is introduced into the controller to improve the transparency of the teleoperation. In addition, there are no approximation functions applied in the proposed controller, which can significantly reduce the complexity and computation of the system. Finally, simulation and experimental results are made to illustrate the availability of this method for practical *** to Practitioners-The motivation of this paper is to develop an algorithm to improve the steady-state and transient-state performance of mobile manipulator teleoperation system without increasing the complexity of the controller. Compared with the existing works, in this paper, the control algorithm without any approximators is proposed and a time-varying prescribed performance function is introduced, which promotes the steady-state and transient-state performance of the system essentially. At the same time, the introduction of force feedback information improves the transparency of the teleoperation system. The feasibility and effectiveness of the algorithm are verified on

关键词： Prescribed performance control (PPC) teleoperation system mobile manipulator nonholonomic constraint approximation function

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What Number of Features is Optimal? A New Method Based on approximation function for Stance Detection Task 2019

What Number of Features is Optimal? A New Method Based on Ap...

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9th International Conference on Information Communication and Management (ICICM)

作者： Vychegzhanin, S. V. Razova, E. V. Kotelnikov, E. V. Vyatka State Univ Kirov Russia

ISBN: (纸本)9781450371889

Selecting a text representation model faces a crucial problem of choosing an optimal number of features. The optimality criterion is the minimum number of features, which allows to achieve (or preserve) the maximum performance. The article suggests a new method of determining the optimal number of features, in which both components of the optimality criterion are taken into consideration. Using the proposed method, we first construct the dependence of task performance on the number of features, then the obtained dependence is approximated on the basis of Weibull distribution function, and the optimal number of features is determined by analyzing the growth rate of this function. We called this method DOFNAF (Determining the Optimal Feature Number by the Approximating function). The proposed method is tested on stance detection task, consisting in identifying the position ("for" or "against"), which the author of the text supports towards the object (or objects) under discussion. The comparison involves constant methods, a method based on the function of the total number of features, a method of performance maximum, as well as Recursive Feature Elimination with Cross-Validation (RFECV) and Correlation-based Feature Selection (CFS) methods. The DOFNAF method allows to determine the minimum number of features compared with the existing methods and at the same time to maintain the classification performance.

关键词： Feature selection stance detection approximation function Weibull function Gini Index RFECV CFS

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Exponential function Generator with Fourth-Order approximation 6

Exponential Function Generator with Fourth-Order Approximati...

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6th European Conference on Electrical Engineering and Computer Science (ELECS)

作者： Popa, Cosmin Radu Fac Elect Telecommun & Informat Technol Bucharest Romania

ISBN: (纸本)9781665497794

The paper presents an original CMOS exponential function generator with improved accuracy. The area of application for CMOS exponential circuits is extremely large, including telecommunication field, medical structures and many analog signal processing blocks. The proposed design is based on a new approximation method for implementing the exponential function that allows a very important increasing of the circuit accuracy. Using a new forth-order approximation function, the original pseudo- exponential structure dynamic range will be more than 33dB, for an error less than 1dB. The circuit has a low-voltage operation and simulations match theoretical results. The circuit is designed for implementing in 0.35 m CMOS technology, being supplied at 3V. The architecture of the proposed exponential function generator allows implementing any continuous mathematical function, the resulted function synthesizer circuit being designed for a low-voltage operation.

关键词： exponential function analog signal processing approximation function Taylor series expansion

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156 dB low-voltage low-power CMOS exponential function generator circuit

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INTEGRATION-THE VLSI JOURNAL 2025年 102卷

作者： Popa, Cosmin Radu Univ Politehn Bucuresti Fac Elect Telecommun & Informat Technol Bucharest Romania

An original exponential function generator is presented, the original approach allowing to extremely accurate approximate the exponential function. The circuit output dynamic range is approximately 156 dB, for a maximal approximation error equal with 1 dB. The new proposed method uses a very precise superior-order approximation function, which is developed for requiring a very ressonable hardware resources for its implementation in CMOS technology. For further improving the accuracy of the proposed function generator circuit, an additional new method using a convenient variable changing is used. The proposed computational structure is designed for low-voltage low-power operation. The circuit is supplied at 1.1 V and its maximal power consumption is approximately 5 mu W. The computational structure is developed for implementing in 0.18 mu TSMC CMOS process, the approximately area being 1600 mu m2. The SPICE simulations of the exponential function generator operation confirm the theoretical estimated results.

关键词： Exponential function generator approximation function CMOS current mode Translinear loop Output dynamic range

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A novel preview control for MLD models and its neural network approximation for real-time implementation: Application to semi-active vibration control of a vehicle suspension

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IET CONTROL THEORY AND APPLICATIONS 2023年第4期17卷 433-445页

作者： Sato, Kaoru Hiramoto, Kazuhiko Niigata Univ Grad Sch Sci & Technol Dept Adv Mat Sci & Technol Niigata Japan Niigata Univ Fac Engn Mech Engn Program Niigata Japan

Advances in image processing technology have made it possible to measure the surface shape of the road ahead while driving. A new semi-active suspension control method considering the forward road surface shape is proposed. A vehicle model equipped with a semi-active suspension can be expressed as an mixed logical dynamical model. When the shape of the road ahead can be measured, the information on future disturbances is available before the vehicle undergoes. In this paper, the finite time optimization problem for the mixed logical dynamical model is formulated to consider the future disturbances as a mixed integer quadratic programming problem in the same way as the conventional control problem without future disturbance. However, the mixed integer quadratic programming problem is hard to obtain the control action within the control cycle period required in the real-time vibration control with general computers for vehicles. In this paper, the reduction of the computational load is achieved by constructing an approximation function of the designed controller. A neural network is adopted for the approximation. The performance evaluation of the proposed method is evaluated by simulations. In the simulation study, the proposed method achieves better ride comfort with the equivalent suspension stroke compared to the traditional methods.

关键词： MLD models Optimisation techniques finite time optimization problem forward road surface shape semiactive suspension control method novel preview control future disturbance vehicle model equivalent suspension stroke image processing technology approximation function Control technology and theory (production) semiactive vibration control quadratic programming Mechanical components Optimal control Vibrations and shock waves (mechanical engineering) control system synthesis vehicle dynamics real-time implementation mixed integer quadratic programming problem control cycle period real-time vibration control Road-traffic system control integer programming control action optimal control mixed logical dynamical model vibration control vehicle suspension conventional control problem Control system analysis and synthesis methods predictive control Mechanical variables control neural network approximation Vehicle mechanics road vehicles suspensions (mechanical components)

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AGV Collision-Free Trajectory Optimization Considering Probability Constraints 43

AGV Collision-Free Trajectory Optimization Considering Proba...

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43rd Chinese Control Conference (CCC)

作者： Xing, Zhida Hao, Yi Chai, Runqi Chai, Senchun Cui, Lingguo Beijing Inst Technol Sch Automat Beijing 100081 Peoples R China

ISBN: (纸本)9798350366907;9789887581581

This paper addresses the optimal collision-free trajectory planning problem for autonomous ground vehicles (AGVs) in the presence of probability constraints. Within a computational framework based on optimal control, a strategy employing a conservative approximation function is proposed to solve the nonlinear trajectory optimization problem for AGVs under probability constraints. This strategy utilizes an approximation function based on hyperbolic tangent functions to replace probability constraints in trajectory optimization with deterministic constraints expressed explicitly, thereby transforming the original AGV trajectory optimization problem with probability constraints into a parameterized nonlinear programming problem. Furthermore, it is proven that the optimal solution under this approximation strategy converges to the optimal solution of the original problem. Finally, numerical results validate the reliability and optimality of this strategy in solving collision-free trajectory optimization problems for AGVs under probability constraints.

关键词： Probability constraints Autonomous Ground Vehicles (AGVs) Trajectory optimization approximation function

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Investigation of Cable Line Heat Mode Parameters in Power Supply Systems 13

Investigation of Cable Line Heat Mode Parameters in Power Su...

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13th International Conference on Renewable Energy Research and Applications

作者： Valtchev, Stanimir Miceli, Rosario Gracheva, Elena Ivanovna Petrov, Almaz Radikovich Tsitson, Ivan Ivanovich Colak, Ilhami Univ Nova Lisboa Fac Sci & Technol UNINOVA CTS Campus Caparica Lisbon Portugal Univ Palermo Dept Engn Palermo Italy Kazan State Power Engn Univ Dept Power Supply Ind Enterprises Kazan Russia Istinye Univ Fac Engn & Nat Sci Dept Elect & Elect Engn Istanbul Turkiye

ISBN: (纸本)9798350375596;9798350375589

The paper develops regression models of dependences of the estimated service life of cable line insulation on the load factor in various operating conditions. The study of thermal modes using approximation functions of the obtained results is carried out. The temperature parameters of the cable line with different types of insulation have been obtained. The results can be used to clarify the temperature modes of cable lines when selecting their cross-sections at the stage of design of electrical engineering systems.

关键词： electrical systems cable lines thermal modes service life approximation function

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Optimal control approach for nonlinear chemical processes with uncertainty and application to a continuous stirred-tank reactor problem

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ARABIAN JOURNAL OF CHEMISTRY 2022年第11期15卷

作者： Wu, Xiang Hou, Yuzhou Zhang, Kanjian Guizhou Normal Univ Sch Math Sci Guiyang 550001 Peoples R China Guizhou Normal Univ Sch Life Sci Guiyang 550001 Peoples R China Southeast Univ Sch Elect Engn Nanjing 210096 Peoples R China Southeast Univ Sch Automat Nanjing 210096 Peoples R China Southeast Univ Key Lab Measurement & Control CSE Minist Educ Nanjing 210096 Peoples R China

Practical chemical process is usually a dynamic process including uncertainty. Stochastic constraints can be used to chemical process modeling, where constraints cannot be strictly satisfied or need not be fully satisfied. Thus, optimal control of nonlinear systems with stochastic constraints can be available to address practical nonlinear chemical process problems. This problem is hard to cope with due to the stochastic constraints. By introducing a novel smooth and differentiable approximation function, an approximation-based approach is proposed to address this issue, where the stochastic constraints are replaced by some deterministic ones. Following that, the stochastic constrained optimal control problem is converted into a deterministic parametric optimization problem. Convergence results show that the approximation function and the corresponding feasible set converge uniformly to that of the original problem. Then, the optimal solution of the determin-istic parametric optimization problem is guaranteed to converge uniformly to the optimal solution of the original problem. Following that, a computation approach is proposed for solving the orig-inal problem. Numerical results, obtained from a nonlinear continuous stirred-tank reactor prob-lem including stochastic constraints, show that the proposed approach is less conservative compared with the existing typical methods and can obtain a stable and robust performance when considering the small perturbations in initial system state.(c) 2022 The Author(s). Published by Elsevier B.V. on behalf of King Saud University. This is an open access article under the CC BY-NC-ND license (http://***/licenses/by-nc-nd/4.0/).

关键词： Optimal control Nonlinear chemical processes Stochastic constraints approximation function Convergence analysis Stirred-tank reactor

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Image Vignetting Correction Using a Deformable Radial Polynomial Model

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SENSORS 2023年第3期23卷 1157页

作者： Bal, Artur Palus, Henryk Silesian Tech Univ Dept Data Sci & Engn Akademicka 16 PL-44100 Gliwice Poland Silesian Tech Univ Biotechnol Ctr Boleslawa Krzywoustego 8 PL-44100 Gliwice Poland

Image vignetting is one of the major radiometric errors that occur in lens-camera systems. In many applications, vignetting is an undesirable effect;therefore, when it is impossible to fully prevent its occurrence, it is necessary to use computational methods for its correction. In probably the most frequently used approach to the vignetting correction, that is, the flat-field correction, the use of appropriate vignetting models plays a pivotal role. The radial polynomial (RP) model is commonly used, but for its proper use, the actual vignetting of the analyzed lens-camera system has to be a radial function. However, this condition is not fulfilled by many systems. There exist more universal models of vignetting;however, these models are much more sophisticated than the RP model. In this article, we propose a new model of vignetting named the Deformable Radial Polynomial (DRP) model, which joins the simplicity of the RP model with the universality of more sophisticated models. The DRP model uses a simple distance transformation and minimization method to match the radial vignetting model to the non-radial vignetting of the analyzed lens-camera system. The real-data experiment confirms that the DRP model, in general, gives better (up 35% or 50%, depending on the measure used) results than the RP model.

关键词： image vignetting image shading vignetting correction single-image vignetting correction flat-field correction vignetting modeling approximation function low-level vision

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AGV Collision-Free Trajectory Optimization Considering Probability Constraints

AGV Collision-Free Trajectory Optimization Considering Proba...

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第43届中国控制会议

作者： Zhida Xing Yi Hao Runqi Chai Senchun Chai Lingguo Cui School of Automation Beijing Institute of Technology

ISBN: (数字)9789887581581

ISBN: (纸本)9798350366907

This paper addresses the optimal collision-free trajectory planning problem for autonomous ground vehicles(AGVs)in the presence of probability constraints. Within a computational framework based on optimal control, a strategy employing a conservative approximation function is proposed to solve the nonlinear trajectory optimization problem for AGVs under probability constraints. This strategy utilizes an approximation function based on hyperbolic tangent functions to replace probability constraints in trajectory optimization with deterministic constraints expressed explicitly, thereby transforming the original AGV trajectory optimization problem with probability constraints into a parameterized nonlinear programming problem. Furthermore,it is proven that the optimal solution under this approximation strategy converges to the optimal solution of the original ***, numerical results validate the reliability and optimality of this strategy in solving collision-free trajectory optimization problems for AGVs under probability constraints.

关键词： Probability constraints Autonomous Ground Vehicles(AGVs) Trajectory optimization approximation function

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