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In this paper, the stability problem of bilateral tele-operation systems with data sampling and communication time delays is considered. Two buffers are introduced in the bilateral teleoperation control framework to deal with the issue that the information transmitted between the master and slave sides suffer from time-varying delays. The mathematical model of bilateral teleoperation systems based...
A wheeled mobile robotic system (WMR) is a kind modular robotic, nonlinear and the system subjected to nonholonomic constraints. It is impossible to obtain an exact dynamics model due to unknown parameters, unpredictable and irregular features, external disturbance. This paper proposes an adaptive robust controller to guide WMR to follow the desired trajectory. The cascade control system is applied...
The problem of regulation oscillatory modes with set characteristics in a controlled subsystem by means of the amplitude of oscillations of the control generator is considered. The control generator is connected with the system control object in a nonlinear feedback mode. The structure of control functions, which depends on the variables of the controlled subsystem is studied for the control generator...
In control systems, actuators always have (in some degree) physical limitations in their capabilities. In the case of mechanisms (robots included), actuators (typically electrical motors) have also limitations at which can operate successfully and safely without damage, for instance in torque and velocity. This paper addresses the shaft displacement control (position control) of a torque-driven nonlinear...
Discuss the numerical method of applying a class contains GI-FADE and FRSE fractional partial differential equations to scientific and engineering fields, and the stability, convergence and solvability of the numerical method. Through numerical experimentations, the reliability and validity of the theoretical results are verified to expand the application range of fractional partial differential equations...
The aim of this article is the simulation and the control of three degree of freedom robotic arms using brushless DC motors. The two arms are used to maintain the stability of the robot in presence of external disturbances. We used an analytical approach based on the inverse dynamic model to determine the necessary configurations of the arms to stabilize the robot. The control of robotic arm is achieved...
In this paper a fixed-order dynamic output feedback controller for consensus of nonlinear multi-agent systems with input delay has been proposed via linear matrix inequalities (LMIs). The overall system is considered to be decentralized and each agent can only receive information from its neighbors. To guarantee consensus in this method, first the multi agent system should be augmented. Then, based...
Teleoperation systems in the medical usage, allows a surgeon to perform a remote distance operation with or without magnification. There is an increasing need to provide telerobots with the ability to interact with unknown and hybrid environments to detect the abnormalities and also performing the diagnostic procedures. In such environments it is challenging to guarantee the whole system stability...
The main purpose of teleoperation in medical usage is to provide technical means to perform a desired task in patient' body. It is important to haptic feedback of sensitive and delicate environment to the surgeon hand's to improve task performance. The Kelvin-Voigt (KV) model for environment, due to physical contradiction is not suitable, but the Hunt-Crossley (HC) model is chosen because of its accuracy...
Stability conditions of the formation of linear SISO agents are described and applied to formation of 25 autonomous quadrocopters. The various information flow graphs are studied from the viewpoints of the formation stability and achievement of the consensus. A way for improving the system performance is proposed and demonstrated by the frequency response analysis and simulation.
A repairable system model which is consisted of two redundant robots and one safety unit is established in this paper. We are devoted to discussing the unique existence of the solution and the stability of the studied system by analyzing the spectrum distribution of the system operator in detail. Thus we can obtain stability analysis of the studied repairable system. Finally, some reliability indices...
In this paper, a local discontinuous Galerkin(LDG) method is designed for solving the Schrödinger equation with three-order spatial derivatives. Our schemes extend the previous work of Xu and Shu [8] on solving the nonlinear Schrödinger equations on LDG method. The L2 stability of the LDG methods is proved for general solutions. Numerical results are shown to illustrate the accuracy and capability...
This paper presents the adaptive hydraulic active suspension applied to the six-wheel off-road vehicle. Both four-link articulated mechanical structure and power transported hydraulic system are constructed. Nonlinear mathematical model is established for the nonlinear uncertain hydraulic system. The advantages of self adaptive suspensions and active suspensions are combined and introduced into the...
This paper is concerned with the problem of teleoperation systems over networks. As is well known, quantization and time delay are unavoidable in computer network communications. Compared with previous work, we consider both of them when analyzing such systems. The controller used in this paper is proportional-derivative(PD) controller, but the output signals of master and slave systems are quantized...
In this paper, we present gait-generation algorithm for a four legged robot which can move in four directions: forward, backward, right and left directions. The robot can also have a combined locomotion including rotation along with each of the four mentioned movements at the same time. Stability is the other issue that we deal with in this paper. Several different methods have been developed to assess...
In this paper, the concept of compound control is introduced. Sliding Mode Control (SMC) and Active Disturbance Rejection Control (ADRC) have their own merits, and also have their own drawbacks, i.e., chattering and the observability. Therefore, compound control is composed of their advantages and can improve the performance of the closed-loop systems.
Dynamic model of the bicycle robot is made by methods based on Lagrangian and using multi-sliding surface of the Hierarchical sliding-mode method controls non-linear underactuated bicycle robot system. This method divided system states into two sub-systems. Two first-level sub-sliding planes are designed, and then the second-level sliding plane is constructed. The ultimate sliding-mode control law...
This paper presents a sufficient stability condition for internet-based tele-operation systems in terms of LMI. The tele-operation scheme is modeled in state-space as a time-delay system in retarded form and a delay-independent stability criterion is extracted. By choosing Lyapunov-Krasovski functional, we show that the internet-based tele-operation system is stable and has good performance under...
In this paper, the effect of deformable environment to the performance of three bilateral teleoperation control schemes for hydraulic actuators are investigated through dynamic simulation. The considered schemes are Force Reflection, Position Error and Lyapunov feedback controllers. Two type of environments are considered, first is spring model and the second one is environment which is described...
It is a key issue for table tennis robot that the flight trajectory of ball could be rapidly predicted within a certain precision. Due to the nonlinear model of the ball's flight, only all state including the position and velocity at each event are catched, could its whole trajectory be obtained. However, since only the position could be measurable by cameras, the velocity should be predicted by the...
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