In this paper, first-order and second-order sliding mode controllers for underactuated manipulators are proposed. Sliding mode control(SMC) is considered as an effective tool in different studies for control systems. ...
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In this paper, first-order and second-order sliding mode controllers for underactuated manipulators are proposed. Sliding mode control(SMC) is considered as an effective tool in different studies for control systems. However, the associated chattering phenomenon degrades the system performance. To overcome this phenomenon and track a desired trajectory, a twisting, a supertwisting and a modified super-twisting algorithms are presented respectively. The stability analysis is performed using a Lyapunov function for the proposed controllers. Further, the four different controllers are compared with each other. As an illustration, an example of an inverted pendulum is considered. Simulation results are given to demonstrate the effectiveness of the proposed approaches.
In this paper, sensor fusion techniques, fused vision/optical sensors and tactile/vision sensors are introduced which are used for learning/identifying features of-tasks related to a robot's part-bringing procedur...
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In this paper, sensor fusion techniques, fused vision/optical sensors and tactile/vision sensors are introduced which are used for learning/identifying features of-tasks related to a robot's part-bringing procedure from a part position to a position over a hole for the purpose of a micro-part insertion in partially unstructured environments. An entropy function, which is a useful measure of the variability and the information in terms of uncertainty, including learning, is introduced to measure the overall performance of a task execution related to a part assembly. By employing a learning approach, the uncertainty associated with the part-bringing task is reduced. The above tools are necessary for a robot manipulator to perform complex assembly, material handling, manufacturing or machining tasks, for example remote maintenance and hazardous material handling, in an unstructured environment.
Astrocytes have potential to break synchrony between neurons. Authors＇ recent researches reveal that astrocytes vary the synchronization threshold and provide an appropriate feedback control in stabilizing neural act...
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Astrocytes have potential to break synchrony between neurons. Authors＇ recent researches reveal that astrocytes vary the synchronization threshold and provide an appropriate feedback control in stabilizing neural activities. In this study, we propose an astrocyte-inspired controller for desynchronization of two coupled limit-cycle oscillators as a minimal network model. The design procedure consists of two parts. First, based on the astrocyte model, the structure of the dynamic controller is suggested. Then, to have an emcient controller, parameters of controller are tuned through an optimization algo- rithm. The proposed bio-inspired controller takes advantages of three important proper- ties： （1） the controller desynchronizes the oscillators without any undesirable effects （e.g. stopping, annihilating or starting divergent oscillations）; （2） it consumes little effort to preserve the desirable desynchronized state; and （3） the controller is robust with respect to parameters＇ variations. Simulation results reveal the ability of the proposed controller.
Recently, problems of network security have become more and more complex. Constructing a safe, survivable and controllable trusted network is becoming the focus of researchers' attention. Because of the special po...
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Recently, problems of network security have become more and more complex. Constructing a safe, survivable and controllable trusted network is becoming the focus of researchers' attention. Because of the special position of electric power industry in national economy and social life, electric power information security has been given particular attention. How to build a safe and controllable electric power trusted network is the research focus and difficulty in the field of electric power information security. In view of the characteristics of the electric power information network and the requirements of electric power information security, a trusted network model for electric power information network based on active defense theory has been presented. The model pays attention to monitor the internal behavior of the network, to establish a trusted power network environment. The model ensures the transmission of trusted chain by using the agent technology and the trusted process security model. As the foundation of the electric power trusted network model, the trusted process security model has been the focus of research, which can monitor the internal behavior of the network.
Aiming at the difficulty of feature extraction for gear fault diagnosis and the problem of traditional classification methods cannot diagnose the faults in wind turbine gearboxes adaptively, a new fault diagnosis meth...
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Blockchain advantages, such as decentralised tamper-proof and smart contracts, are naturally suitable for the trading needs of energy internet, dealing with the problems of low efficiency, waste of resources, privacy ...
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This paper studies a dynamic state estimation problem for power systems, which can be seen as the quasi-static systems. The state vector of each subsystem(called node) in power networks is expressed by measurements. B...
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ISBN:
(纸本)9789881563897
This paper studies a dynamic state estimation problem for power systems, which can be seen as the quasi-static systems. The state vector of each subsystem(called node) in power networks is expressed by measurements. Based on a distributed maximum a posteriori(MAP) estimation technique, a fully distributed state estimation method is presented to update the local state at each time instant. Also, the assumption of local observability of every node is no longer needed. Tests on the IEEE 118-bus system are used to show the performance of the proposed approach and compare its results with a centralized state estimation method providing the optimal state estimate for the entire power networks, a local state estimation method using the edge measurements as the local measurements to estimate its local state, and a distributed static state estimation algorithm.
Industrial serial robots need high stiffness to keep absolute pose accuracy and meet the requirements in practical applications. However, the weak stiffness feature of robot joints and the payloads affected on robot e...
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Industrial serial robots need high stiffness to keep absolute pose accuracy and meet the requirements in practical applications. However, the weak stiffness feature of robot joints and the payloads affected on robot end-effector, which will also increase the pose error of robot. Especially, the existing calibration methods often consider under no-payload condition without discussing the payload state. In this paper, we report a new industrial serial robot composed by a new harmonic reducer: Model-Y, based on high accuracy and high stiffness, and a kinematic parameter calibration algorithm which is based on a harmonic reducer forcedeformation model. To decrease the accuracy effects of payload, an iterative calibration method for kinematic parameters with payload situation was proposed. Simulation and experiments are conducted to verify the effectiveness of the proposed calibration method using the self-developed industrial serial robot. The results show a remarkably improved accuracy in absolute position and orientation with the robot's payload range. The position mean error has 70% decreased to 0.1 mm and the orientation mean error diminished to less than 0.01° after calibration with compensation. Additionally, online linear and circular tests are carried out to evaluate the position error of the robot during large-scale spatial and low-speed continuous movement. The accuracy is consistent with the previous calibration results, indicating the effectiveness and advantages of the proposed strategy in this article.
The health status evaluation of electric power equipment is an important issue with extensive concerns in power system community around the globe. In consideration of the uncertain characteristics of the monitoring da...
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DNA computing, currently a hot research field in information processing, has the advantages of parallelism, low energy consumption, and high storability, therefore, it has been applied to a variety of complicated comp...
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DNA computing, currently a hot research field in information processing, has the advantages of parallelism, low energy consumption, and high storability, therefore, it has been applied to a variety of complicated computational problems. The emerging field of DNA nanotechnology has also developed quickly; within it, the method of DNA strand displacement has drawn great attention because it is self-induced, sensitive, accurate, and operationally simple. This article summarizes five aspects of the recent developments of DNA-strand displacement in DNA computing:(1) cascading circuits;(2) catalyzed reaction;(3) logic computation;(4) DNA computing on surfaces; and(5) logic computing based on nanoparticles guided by strand displacement. The applications and mechanisms of strand displacement in DNA computing are discussed and possible future developments are presented.
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