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The Normalized Analysis of a Surface Heterogeneous Reaction of a Propane/Air Mixture into a Micro-Channel

Chinese Physics Letters 2012年第12期29卷 132-136页

作者： A.Fanaee J.A.Esfahani Center of Excellence on Modelling and Control Systems(CEMCS)&Mechanical Engineering Department Ferdowsi University of MashhadMashhad 91775-1111Iran

The effect of catalytic surface reaction on non-reactive flow in micro-channels is *** hydraulic diameter of the channel is considered within the range of 0.2-1.2 mm,and the channel length is considered to be 5 *** whole length of the channel wall is coated with a *** sensitivity analysis shows that the effect of normalized hydraulic diameter is more than the normalized longitude coordinates in accordance with the existence of the large ratio of surface area to volume in the *** validation of this model,the variation of fuel conversion is compared with the published experimental data and shows an acceptable agreement.

关键词： catalyst. normalized coordinates

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Enhanced adaptive nonlinear extended state observer for pure feedback systems with matched and mismatched disturbances

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control Theory and Technology 2024年第2期22卷 254-268页

作者： Mahtab Delpasand Mohammad Farrokhi School of Electrical Engineering Iran University of Science and TechnologyTehran16846-13114Iran Center of Excellence for Modelling and Control of Complex Systems Iran University of Science and TechnologyTehran16846-13114Iran

In this paper, an enhanced adaptive nonlinear extended state observer (EANESO) for single-input single-output pure feedback systems in the presence of external time-varying disturbances is proposed. In this paper, a nonlinear system with matched and mismatched disturbances is considered. The conventional extended state observer (ESO) can only be applied to systems that are in the form of integral chains. Moreover, this method has limitations in the face of mismatched disturbances. In the presence of time-varying disturbances, the traditional ESOs cannot estimate the disturbances accurately. To overcome this limitation, an EANESO is proposed in this paper. The main idea is to design the nonlinear ESO (NESO) to estimate the states of the system and multiple disturbances simultaneously. The observer gains are considered time-varying and adjusted with adaptation laws to improve the estimation accuracy and overcome the peaking phenomenon. Next, the proposed controller is designed based on output feedback to eliminate the effects of multiple disturbances and stabilize the closed-loop system. Subsequently, the stability analysis of the closed-loop system and convergence of the observer error are discussed. Finally, the proposed method is applied to the inverted pendulum system. The simulated results show good performance of the proposed method as compared with a recently published scheme in the related literature.

关键词： Nonlinear extended state observer Enhanced adaptive extended state observer Adaptation law Multiple-channel disturbances Inverted pendulum system Time-varying gain

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Robot assisted rehabilitation of the arm after stroke:prototype design and clinical evaluation

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Science China(Information Sciences) 2017年第7期60卷 252-258页

作者： Liang PENG Zeng-Guang HOU Long PENG Lincong LUO Weiqun WANG State Key Laboratory of Management and Control for Complex Systems Institute of AutomationChinese Academy of Sciences University of Chinese Academy of Sciences CAS Center for Excellence in Brain Science and Intelligence Technology

Robot assisted rehabilitation training is a promising tool for post-stroke patients’ recovery, and some new challenges are imposed on robot design, control, and clinical evaluation. This paper presents a novel upper limb rehabilitation robot that can provide safe and compliant force feedbacks to the patient for the benefits of its stiff and low-inertia parallel structure, highly backdrivable capstan-cable transmission, and impedance control method in the workspace. The "assist-as-needed"(AAN) clinical training principle is implemented through the "virtual tunnel" force field design, the "assistance threshold" strategy, as well as the virtual environment training games, and preliminary clinical results show its effectiveness for motor relearning for both acute and chronic stroke patients, especially for coordinated movements of shoulder and elbow.

关键词： rehabilitation robot passive training active training force feedback impedance control

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Parameter estimation survey for multi-joint robot dynamic calibration case study

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Science China(Information Sciences) 2019年第10期62卷 102-116页

作者： Shaolin ZHANG Shuo WANG Fengshui JING Min TAN The State Key Laboratory of Management and Control for Complex Systems Institute of AutomationChinese Academy of Sciences University of Chinese Academy of Sciences CAS Center for Excellence in Brain Science and Intelligence Technology

Accurate model parameters are the basis of robot dynamics. Many linear and nonlinear models have been proposed to calibrate the inertial parameters and friction parameters of multi-joint ***, methods of choosing a model and calculating its parameters still have few summaries. This paper reviews typical linear/nonlinear models and different calculation methods for robot dynamic *** simulations, the features of different methods are analyzed, including torque error, parameter error, model adaptability, solution time, and anti-interference ability of the calibration results. Finally, an experiment performed on a six-degree-of-freedom industrial manipulator is used as an example to illustrate how to select the model for a specified robot. These comparisons and experiments provide references for the parameter calibration of multi-joint robots.

关键词： dynamic parameter calibration friction calibration robot dynamics industrial manipulator dynamic models

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A simulator with an elastic guidewire and vascular system for minimally invasive vascular surgery

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Science China(Information Sciences) 2018年第10期61卷 250-252页

作者： Xiaoran CHENG Xiaoliang XIE Guibin BIAN Zengguang HOU Shiqi LIU Zhanjie GAO State Key Laboratory of Management and Control for Complex Systems Institute of AutomationChinese Academy of Sciences University of Chinese Academy of Sciences CAS Center for Excellence in Brain Science and Intelligence Technology

Simulators play an important role in minimally invasive vascular surgery training. A challenging task for the simulator is to model an elastic guidewire and an elastic vascular system, both of which are important aspects for vascular ***, many simulators treat the virtual vascular system as a rigid object, which reduces the immersion of operators. In this study, a virtual guidewire is first modeled based on Cosserat rod

关键词： Pi Figure A simulator with an elastic guidewire and vascular system for minimally invasive vascular surgery

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Laminar film condensation on a nanosphere

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Journal of Nanotechnology in Engineering and Medicine 2012年第1期3卷 1-7页

作者： Esfahani, J.A. Koohi-Fayegh, S. Center of Excellence on Modelling and Control Systems (CEMCS) Mechanical Engineering Department Ferdowsi University of Mashhad Mashhad P.O. Box 91775-1111 Iran

The present work investigates an analytical study on the problem of laminar film condensation on a nanosphere. Due to the microscale interaction, the problem is analyzed by taking into account the effects of slip in velocity and jump in temperature. A relation is derived for the liquid film thickness in the form of a nonlinear differential equation which is solved numerically using the fourth order Runge-Kutta method. Finally, the effect of velocity slip and temperature jump on different condensation parameters including the liquid film thickness, velocity and temperature profiles, Nusselt number, and liquid mass flow rate is discussed. It is found that the increase in the velocity slip and temperature jump results in a thinner liquid film and therefore increases the heat transfer coefficient. © 2012 by ASME.

关键词： Film condensation Nanosphere Nusselt number Temperature jump Velocity slip

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Some derivative-free solvers for numerical solution of SODEs

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SeMA Journal 2015年第1期68卷 17-27页

作者： Soheili, Ali R. Soleymani, F. The Center of Excellence on Modelling and Control Systems Ferdowsi University of Mashhad Mashhad Iran Department of Applied Mathematics School of Mathematical Sciences Ferdowsi University of Mashhad Mashhad Iran

In this paper, some variants of stochastic solvers free from derivatives for Ito ^ stochastic ordinary differential equations (SODEs) are given. The derived strong variants are convergent and explicit. Then, some implicit solvers are also proposed. Numerical results are reported for confirming convergence properties and for comparing the behavior of these methods for pathwise approximation of SODEs. © 2015, Sociedad Española de Matemática Aplicada.

关键词： Heuristic derivation Numerical solution Stochastic differential equations Stochastic Runge–Kutta methods Strong sense

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Economic Equilibrium with Random Transactions 2

Economic Equilibrium with Random Transactions

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2nd International Conference on control systems, Mathematical Modeling, Automation and Energy Efficiency, SUMMA 2020

作者： Zhukova, Aleksandra Pospelov, Igor G. Moscow Institue of Physics and Technology Federal Research Center Computer Science and Control of Ras Dept. of Mathematical Modelling of Economic Systems Dept. of Mathematical Modelling of Complex Systems and Optimization Dept of Theoretical Economics Moscow Russia

ISBN: (纸本)9781728188409

This paper presents the advances in modelling the system of agents under the conditions of random transactions between them. We face certain challenges in this project which we would like to highlight in this presentation. The agents in the modelled system are a large number of consumers, a large number of producers and the bank as the intermediary. Consumers take loans from the bank to spend on consumption goods and producers borrow to make investment at random moments of time. The moments of time the agents deal form the Poisson flow. We present the approach to agents' optimal control problems by the Lagrange method instead of dynamic programming. This enables us obtaining the expressions for the optimal feedback control which appear to be linear in state variables. The solution to the optimal control problems are obtained using asymptotic methods assuming large frequency of transactions. Using the linearity of the agents' optimal control, we may aggregate description of agents, stock-flow consistent on the average. Instead of an ensemble of independent random transactions by agents, the description of the aggregate dynamics is deterministic. The system of equations for the aggregate dynamics is reduced to one equation. There are two cases of this equation, depending on the description of the bank. The equation has a specific form, its numerical analysis is challenging. We provide numerical results and discuss further directions of research. © 2020 IEEE.

关键词： Random processes

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A Novel Heterogeneous Actor-critic Algorithm with Recent Emphasizing Replay Memory

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International Journal of Automation and computing 2021年第4期18卷 619-631页

作者： Bao Xi Rui Wang Ying-Hao Cai Tao Lu Shuo Wang State Key Laboratory of Management and Control for Complex Systems Institute of AutomationChinese Academy of SciencesBeijing 100190China University of Chinese Academy of Sciences Beijing 100049China Center for Excellence in Brain Science and Intelligence Technology Chinese Academy of SciencesShanghai 200031China

Reinforcement learning(RL) algorithms have been demonstrated to solve a variety of continuous control tasks. However,the training efficiency and performance of such methods limit further applications. In this paper, we propose an off-policy heterogeneous actor-critic(HAC) algorithm, which contains soft Q-function and ordinary Q-function. The soft Q-function encourages the exploration of a Gaussian policy, and the ordinary Q-function optimizes the mean of the Gaussian policy to improve the training efficiency. Experience replay memory is another vital component of off-policy RL methods. We propose a new sampling technique that emphasizes recently experienced transitions to boost the policy training. Besides, we integrate HAC with hindsight experience replay(HER) to deal with sparse reward tasks, which are common in the robotic manipulation domain. Finally, we evaluate our methods on a series of continuous control benchmark tasks and robotic manipulation tasks. The experimental results show that our method outperforms prior state-of-the-art methods in terms of training efficiency and performance, which validates the effectiveness of our method.

关键词： Reinforcement learning(RL) actor-critic experience replay training efficiency manipulation skill learning

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Phase locked-in loop design with pre-specified transient performance

Phase locked-in loop design with pre-specified transient per...

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SPIE - The International Society for Optical Engineering

作者： Ng, Boon Ping Zhang, Ying Soh, Yeng Chai Singapore Institute of Manufacturing Technology 71 Nanyang Avenue Singapore 638075 Singapore Center for Modelling and Control of Complex Systems School of Electrical and Electronics Enginering Nanyang Technological University Nanyang Avenue 639798

In this paper, we present a design and a design scheme for the phase locked-in loops satisfying given specifications. The proposed design suggests imposing an additional control signal on the normal input to the variable controlled oscillator (VCO) of the phase locked-in loop (PLL). Based on this design, a scheme of using the second method of Lyapunov is developed to choose the additional control signal and the loop filter parameters of the PLL. The proposed design and design scheme have improved the conventional PLL design results by obtaining a phase locked-in loop with pre-specified performance. The design scheme is based on nonlinear model of the PLL and it is applicable to the design of high order PLLs. Simulations results are reported to demonstrate the effectiveness of the proposed scheme.

关键词： Phase locked loops

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