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This paper proposes a DC link controller based on H∞ method for robust and reliable operation of a single-phase grid-connected inverter with an LCL-filter in photovoltaic (PV) applications. The H∞ DC link controller minimizes the bus voltage fluctuations caused by the power variations of PV system. Also, the controller ensures system robustness against such power variations, which conventional controllers...
We introduce a new approach for the elastic registration of high-resolution 3D polarized light imaging (3D PLI) data of histological sections of the human brain. For accurate registration of different types of 3D PLI modalities, we propose a novel intensity similarity measure that is based on a least-squares formulation of normalized cross-correlation. Moreover, we present a fully automatic registration...
This paper introduces a method to improve the feedback accuracy using multisensor data fusion. Flexibility in cables and unmodeled rotation of feeder pulley in the spatial workspace cause unreliability in the encoder data as well as sagging in cables. The purpose of this work is to provide an effective scheme to combine other sensors' information from multiple sources to increase the precision and...
This paper focuses on a lower limb walking assistant robot. This robot has been designed and modeled for two tasks of facilitating healthy people, and assisting patients for walking. First, basic concepts of the motion mechanism are presented. Next, its kinematics and dynamics equations have been developed. Kinematics analysis has been done using Denavit-Hartenberg scheme to obtain position, velocity...
Using Bhuman walking engine, this paper presents an LTI model for Nao robot walking control. The robot is assumed as a point mass in a 2-D maneuver. Model calculations and validation have been done using experimental data, performing various tests on the robot, and using system identification tools. Afterwards, a robust controller is designed to control the robot position in the horizontal (x-y) plane...
This paper investigates the problem of controlling flexible-joint underactuated manipulators in task space. A lower number of actuators than degrees of freedom alongside flexibility of joints make this mission a challenging task. Problems may arise such as poor tracking performance due to structured and unstructured uncertainties. Here, a controller with two internal loops comprising a free dynamic...
The fuzzy logic controller for ball and plate based on Mamdani maximum-product method is proposed in this paper to improve the performance of the system. Various kinds of ball and plate test-beds, considered as typical multivariable, nonlinear systems, are usually employed to conduct researches for evaluating developed control algorithms. Although most of these equipment have been presented as two...
This study extends the application of Unbiased Criterion (UC) method to investigate the robustness of an identified fuzzy model for nonlinear dynamical systems in their different operating conditions. Heat Recovery Steam Generator (HRSG) as specific boilers in combined power plants exhibit challenging behaviors in startup, shut down and parallel conditions such as Swell and Shrink. In order to analyze...
The motor vehicles industry has shown a mechatronic system with intelligent and autonomous properties. The mechatronics system is integration of hardware components, implementation of advance control function characterize and information technology. Vehicle suspensions systems typically rated by its ability to provide good road handling and improve passenger comfort. Active suspension poses the ability...
In this paper, a robust controller is designed based on μ-synthesis method for grid-connected inverters. The performance of the controller is made robust against realistic uncertainties including the time delay and parameter changes, while the resonant oscillations are actively damped. The designed controller only relies on output feedback eliminating the need for extra feedback sensors that are normally...
In this paper, a robust controller is designed to control the output voltage of an inverter with an LC type output filter in an islanded microgrid. The proposed controller includes a local droop controller, as well as a robust controller that is designed based on the μ-synthesis technique. The performance of the designed controller is proven to be robust to the uncertainties which include the time...
In this paper, a robust controller is designed for the load frequency control (LFC) system in an islanded microgrid with multiple synchronous generation systems. This control strategy can be readily applied to an islanded microgrid which consists of renewable distributed generation and energy storage systems. The robust controller proposed in this paper includes multiple local controllers that are...
Accurate large signal analysis and modeling of Power Electronics converters are essential for achieving high performance and reliable designs. Converter topologies with large signal variations are conventionally analyzed using numerical methods, averaged or inaccurate analyses. In this paper, a mathematical theorem based on Laplace transform is developed to derive the steady state response of periodic...
For many years pneumatic actuators have had a significant role as a technology in many applications. But nonlinearities such as air compressibility and friction make pneumatic systems difficult to apply in accurate control strategies. In this paper, pneumatic cylinder actuator system has been modeled considering a nonlinear friction characteristic. Since the unknown friction parameters cannot be directly...
Maintaining the balance or stability of legged robots in natural terrains is a challenging problem. Besides the inherent unstable characteristics of legged robots, the sources of instability are the irregularities of the ground surface and also the external pushes. In this paper, a push recovery framework for restoring the robot balance against external unknown disturbances will be demonstrated. It...
Quadruped animals have high agility and grace skills in the motion over natural environment. An important feature of such animals is their abilities in the selection of appropriate gait in the response to the terrain irregularities and also the smooth transition between them in order to increase the stability or conserve the energy. In this paper, a Cartesian CPG-based controller for the gait generation...
To obtain satisfactory performance for legged robots, they should be able to move on natural environment stably. In this article, the path planning of a quadruped robot in the motion over uneven terrains will be investigated. One of major problems for traversing uneven terrains is the robot stability. Thus, a condition to guarantee the robot stability over such terrains will be proposed. This condition...
This paper focuses on a robotic human-like leg. This robot was designed and modeled for task of kicking soccer ball to desired target. In addition, applications of this robot have been explained and its kinematics and dynamics equations have been developed. Kinematic analysis has been done using Denavit-Hartenberg method and position, velocity and acceleration of center of mass (CoM) of all links...
Quadruped robots have many advantages over other robots. Their excellent potentials to traverse different terrains are one of main advantages which distinguish these robots from wheeled mobile robot. In this article, the gait planning problem and also the design of an appropriate controller for a quadruped robot will be investigated. To this end, an explicit dynamics model of an 18-DOF quadruped robot...
Rehabilitation is the best approach for patients who suffer physical disability of their upper-limbs. Maintaining the intensity of exercise during treatment is the main factor that makes the robots suitable for rehabilitation since robots do not get tired and do the exercises with constant intensity under supervision of the doctor. Two main categories of rehabilitation robots are End-Effector based...
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