To improve the approximation capabilities of RBF networks, centers of adequate widths should be placed more densely on regions of higher than on regions of lower absolute second derivative of the function to be approx...
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To improve the approximation capabilities of RBF networks, centers of adequate widths should be placed more densely on regions of higher than on regions of lower absolute second derivative of the function to be approximated. This new concept is called second derivative dependent center placement. Using a test function especially designed to study this relationship, several RBF networks are designed and compared.
This paper presents a sliding mode control strategy for cars with an active steering system. The goal of control is to achieve a fixed dynamic relationship between the driver’s steering command and the vehicle’s yaw...
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This paper presents a sliding mode control strategy for cars with an active steering system. The goal of control is to achieve a fixed dynamic relationship between the driver’s steering command and the vehicle’s yaw rate in spite of a wide range of car and road parameters and varying operating conditions. The steady behavior should still be similar to conventional cars. Control design is based on a linear single track model and exploits the invariance property of sliding mode control. Implementational issues of the design process are discussed in detail in the form of robust continuous nonlinear controller to avoid chattering.
Features of an available computation environment for robot-dynamics design are described. These are environments for object-oriented mechatronics/robot dynamics modeling, for executing dynamics simulation experiments,...
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ISBN:
(纸本)0818653329
Features of an available computation environment for robot-dynamics design are described. These are environments for object-oriented mechatronics/robot dynamics modeling, for executing dynamics simulation experiments, for multiobjective parameter and trajectory optimization, and for multivariate result visualization. The environments have a common look and feel and are coherently integrated using an engineering database system.
Autonomous navigation in unknown cluttered environments is one of the corner-stones of future applications of mobile robots. The complexity even of seemingly simple problems like point-to-point travel, to be solved in...
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Autonomous navigation in unknown cluttered environments is one of the corner-stones of future applications of mobile robots. The complexity even of seemingly simple problems like point-to-point travel, to be solved in real-time, calls for a hierarchical system architecture. We present a three-layered path control system with three modules 'global planning', 'local navigation', and 'collision avoidance'. Each module is restricted to a subtask of limited competence and responsibility, allowing for on-line implementation within the associated time frame. Suitable module interaction provides the desired behavior of the overall system. This paper summarizes the main idea of each of the three modules. Experimental results with the Siemens mobile platform ROAMER illustrate the methodology and performance of the path control system in unprepared cluttered environments.
Computer-Aided Control Engineering (CACE) environments, in order to be reusable in a broad spectrum of applications, have to be based on an open software framework which provides seven classes of services: database se...
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ISBN:
(纸本)0780318005
Computer-Aided Control Engineering (CACE) environments, in order to be reusable in a broad spectrum of applications, have to be based on an open software framework which provides seven classes of services: database services;model-definition services;algorithmic services;tool-control services;task-control services;user-interaction services;message services. This is detailed at hand of the available ANDECS framework A_RSYST.
The ANDECS - Matlab environment provides two alternatives for databased computational experimenting using Matlab: The module Amatlab is a re-implementation of the classic matlab syntax to be used for interactive speci...
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ISBN:
(纸本)0780318005
The ANDECS - Matlab environment provides two alternatives for databased computational experimenting using Matlab: The module Amatlab is a re-implementation of the classic matlab syntax to be used for interactive specification of matrix calculations in modular computation sequences. This syntax is extended to allow database access for data communication with other databased modules. Alternatively, the module PROMAT allows to use commercial MATLAB via process communication with online data transfer between the ANDECS database and the MATLAB workspace in both directions. This allows a convenient use of the matlab syntax and a coherent integration of M-file Toolboxes in any module sequence of the control-engineering software environment ANDECS.
Mobile robots with non-holonomic kinematics have three degrees of freedom for planar motion, but only there are two control inputs available. The stabilization problem for such robots is known not to be solvable via s...
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Mobile robots with non-holonomic kinematics have three degrees of freedom for planar motion, but only there are two control inputs available. The stabilization problem for such robots is known not to be solvable via smooth time-invariant feedback. We propose to utilize a Lyapunov function to prescribe a set of desired trajectories to navigate robot to a specified configuration. Ideal tracking of the prescribed trajectories is achieved by exploiting the invariance property and the order reduction property of sliding mode control. The mobile robot is shown to be exponentially stabilizable for a class of quadratic Lyapunov functions.
The fuzzy-control methodology can be seen as a systematic way to specify controllers with nonlinear gain surfaces. To properly tune such controllers, computer-aided techniques can be applied provided appropriate plant...
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ISBN:
(纸本)0780318005
The fuzzy-control methodology can be seen as a systematic way to specify controllers with nonlinear gain surfaces. To properly tune such controllers, computer-aided techniques can be applied provided appropriate plant models are available such as in more classical design approaches. In particular, it is shown how a multi-models/multi-criteria design for controllers with fuzzy logic can be carried out by using the ANDECS_MOPS Multi-Objective Programming system. For that a Control Data Object 'Fuzzy-Controller' is developed together with a graphical editor for defining the linguistic variables. This represents the dynamic synthesis part of the design framework. Using a model building environment like Dymola or ACSL which is linked to ANDECS via DSblock, the fuzzy controller connected to dynamic plant models can be optimized by MOPS. This is demonstrated for a multicriteria design problem for an aerodynamically unstable aircraft.
Highway automation is a promising approach to cope with increasing road traffic and congestions. An important control subtask of an Intelligent Vehicle/Highway system is automatic steering for lateral vehicle control....
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Highway automation is a promising approach to cope with increasing road traffic and congestions. An important control subtask of an Intelligent Vehicle/Highway system is automatic steering for lateral vehicle control. Due to system uncertainties and the wide range of operating conditions, state-of-the-art robust control techniques are required. This paper introduces two automatic steering controllers for cars driving under highway conditions. The control design is based on sliding mode control and robust state observation. It is shown that good tracking of a reference path, delineated either continuously or discretely, can be achieved with a minimum effort in sensing and without preview of the road curvature.
This paper establishes a general framework for the passing of mobile robots through narrow passages. Under such circumstances, the artificial potential method often leads to oscillatory motion (Koren et al. 1991) or e...
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This paper establishes a general framework for the passing of mobile robots through narrow passages. Under such circumstances, the artificial potential method often leads to oscillatory motion (Koren et al. 1991) or even lock-up situations (Khosla et al. 1988, Noborio et al. 1990). Sliding mode theory is utilized to examine the gradient of an artificial potential in the vicinity of the equi-distance line between the passage constraints. State-dependent and time-dependent smoothing methods are introduced to enable safe passing. The methodology is illustrated in experiments with the Siemens mobile platform ROAMER.
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