In the paper the path following problem for a wheeled mobile robot of (2,0) type is considered. the Serret-Frenet frame is used to describe the robot relative to the desired path. the way how to transform obtained equ...
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In the paper the path following problem for a wheeled mobile robot of (2,0) type is considered. the Serret-Frenet frame is used to describe the robot relative to the desired path. the way how to transform obtained equations describing kinematic model derived with respect to the Serret-Frenet frame into the chained form is introduced. the kinematic control algorithm which is a combination of Astolfi algorithm - used for systems in the chained form - and Samson algorithm - dedicated to the unicycle - is proposed and compared to the Morin-Samson algorithm. Simulation results are shown to verify the effectiveness of the proposed method.
the paper proposes a carrier synchronization procedure for high-order QAM modulated signals that uses a decision-directed extended Kalman filtering (EKF) technique. the proposed method combines the Kalman filter with ...
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the paper proposes a carrier synchronization procedure for high-order QAM modulated signals that uses a decision-directed extended Kalman filtering (EKF) technique. the proposed method combines the Kalman filter with a lock detector to establish the status of the synchronization process, modifying adaptively the Kalman filter parameters. As compared withthe complete EKF filter, the proposed synchronization algorithm simplifies the Kalman measurement model to a single scalar equation reducing significantly the computational complexity of the algorithm. Simulations show that the simplified Kalman algorithm has equivalent synchronization performances withthe complete EKF filter.
In the paper a multicontroller-based switchable control system for nonlinear MIMO plants is presented. the control system synthesis is carried out by linearization of the adopted nonlinear plant model at its operating...
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In the paper a multicontroller-based switchable control system for nonlinear MIMO plants is presented. the control system synthesis is carried out by linearization of the adopted nonlinear plant model at its operating “points”. thus the considered structure contains a collection of linear feedback controllers. In the first stage of the adopted method a great number of controllers is synthesized. the paper discuss problems with reduction of such controller set to make it smaller and possible to implement the system in e.g. constrained memory of programmable automation devices. As an example a nonlinear model of a drilling vessel in three degrees of freedom (3DOF) on a sea surface is used as a MIMO plant to be controlled. Here the controller set depends on the preset ship yaw angle and the velocity of the sea current. the methods of reduction and their possible results are compared and discussed.
the lifetime of a considerable number of satellites is significantly shortened by malfunctions occurring during operational period; therefore, unmanned satellite servicing missions are considered. this paper presents ...
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the lifetime of a considerable number of satellites is significantly shortened by malfunctions occurring during operational period; therefore, unmanned satellite servicing missions are considered. this paper presents an approach for analyses of various configurations and parameters of manipulator intended for on-orbit servicing. It is based on analytical method used to analyse workspace and singularities of the manipulator mounted on a free-floating satellite, and on numerical simulations of mission-specific manoeuvers (e.g., capture of malfunctioned satellite). the application of this approach to obtain parameters of the manipulator most suitable for defined servicing tasks is presented.
We consider the feedback stabilization of quasilinear hyperbolic systems on star-shaped networks. We present boundary feedback controls with varying delays. the delays are given by C 1 -functions with bounded derivati...
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We consider the feedback stabilization of quasilinear hyperbolic systems on star-shaped networks. We present boundary feedback controls with varying delays. the delays are given by C 1 -functions with bounded derivatives. We obtain the existence of unique C 1 -solutions on a given finite time interval. In order to measure the system evolution, we introduce an L 2 -Lyapunov function with delay terms. the feedback controls yield the exponential decay of the Lyapunov function with time. this implies the exponential stability of the system. Our results can be applied on the stabilization of the isothermal Euler equations with friction that model the gas flow in pipe networks.
A well-known reactive motion planning technique, the dynamic window approach (DWA) provides an elegant way to navigate safely in the presence of obstacles, also taking the dynamic properties of the robot into account....
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A well-known reactive motion planning technique, the dynamic window approach (DWA) provides an elegant way to navigate safely in the presence of obstacles, also taking the dynamic properties of the robot into account. Most of the DWA-based methods have the same limitation, namely they use an objective function consisting of weighted terms. Different situations require different weights, however, there is no algorithm for choosing them. this paper presents a global dynamic window-based navigation scheme using model predictive control and having no weighted objective function. Former DWA-based methods take dynamic limitations of the robot by acceleration constraints into account. In contrast withthat, the proposed approach utilizes a dynamic motion model of the robot.
the paper deals with a set of the mathematical algorithms for a time parameterization of the motion paths of the machine tools. the key descriptors of the paths follow from CAD documentation, technical drawings or fro...
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the paper deals with a set of the mathematical algorithms for a time parameterization of the motion paths of the machine tools. the key descriptors of the paths follow from CAD documentation, technical drawings or from technological demands. the presented algorithms provide a time mapping of individual path coordinates. the algorithms are based on the kinematical relations and on analytical geometry in space. they work with position, velocity, acceleration and jerk quantities. All algorithms are implemented in a path simulator, which was developed as a user friendly utility windows application. the described mathematical principles are demonstrated by several testing motion paths.
In this article we discuss the dynamic modelling of the propulsion system of an autonomous underwater vehicle (AUV), and also a method of fault tolerant control in an AUV that has four vertical and two horizontal thru...
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In this article we discuss the dynamic modelling of the propulsion system of an autonomous underwater vehicle (AUV), and also a method of fault tolerant control in an AUV that has four vertical and two horizontal thrusters. Firstly we made an analysis of the dynamic and kinematic effects of the vehicle, subsequently we did an analysis of dynamic propulsion system and then found out the state of the art of the underwater vehicle. through a series of simulations, it was validated our propulsion model system and its efficiency of the fault tolerant control working in conjunction withthe purpose of the vehicle to follow a desired path even when some thrusters is faulty.
this paper describes how to apply a group of alternative methodologies to the modeling and simulation of a three phase rectifier. the system is a full bridge rectifier with RC load, that consist of diodes that are mod...
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this paper describes how to apply a group of alternative methodologies to the modeling and simulation of a three phase rectifier. the system is a full bridge rectifier with RC load, that consist of diodes that are modeled withthe accurate and close-to-real constituve relation of Shockley. this constitutive relation bring an unvariable topology and a non linear nature to the whole system. the emerging non linearities are handled withthe described methodologies, and a procedure to formulate differential-algebraic equations (DAE) is reviewed. the obtained DAE is numerically solved and simulation results are presented. In order to prove the significance of the modeling and simulation approach, non standard conditions, such as unbalanced sources are included.
Livelong education in electro-mechanical industry is increasingly important as it allows practicing engineers and technicians to gain the knowledge necessary to cope withthe fast development and consequently with hig...
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Livelong education in electro-mechanical industry is increasingly important as it allows practicing engineers and technicians to gain the knowledge necessary to cope withthe fast development and consequently with higher demands on their workplaces. this paper addresses different aspects of development and execution of such industrial training. Concrete solutions and results are presented including: (1) extensive international knowledge needs analysis in electro-mechanical sector, (2) e-learning solutions for industry including learning management systems and application of remote working stations/experiments for practical part of the training and (3) examples of the training modules from robotics developed for industry. Applied solutions and education methodology is evaluated by feedback obtained from the training participants. Based on a gained experience a long-term perspective and possible further development direction of modern industrial education is also addressed.
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