In this paper, we propose a method for self-calibration of robotic hand cameras by means of active motion of the robot. Through tracking a set of world points of unknown coordinates, the internal parameters of the cam...
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In this paper, we propose a method for self-calibration of robotic hand cameras by means of active motion of the robot. Through tracking a set of world points of unknown coordinates, the internal parameters of the cameras (including lens distortions), the mounting parameters as well as the coordinates of the world points are estimated. The approach is fully autonomous, in that no initial guesses of the unknown parameters are to be provided from the outside by humans for the solution of a set of nonlinear equations. Sufficient conditions for a unique solution are derived in terms of controlled motion sequences. To improve robustness of the calibration, we propose to identify the best lens-distortion model by using F-test. Furthermore, a method is proposed to minimize the effect of robot motion uncertainties by motion planning. Experimental results in both a simulated and a real environments are reported.
Active steering systems can help the driver to master critical driving situations, for example aquaplaning and μ-split braking. In these situations it is likely that the tires reach their performance limits, where no...
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Active steering systems can help the driver to master critical driving situations, for example aquaplaning and μ-split braking. In these situations it is likely that the tires reach their performance limits, where nonlinear effects like saturation play an important role. Tires are the part in vehicle dynamics afflicted with the highest degree of nonlinearity - due to saturation - and uncertainty - due to whether conditions. Therefore, active steering systems have to be designed considering the uncertain and nonlinear tire characteristics which are determined by the road-tire-contact. This paper demonstrates how an important tire parameter, the cornering stiffness, can be estimated by measurement of dynamic vehicle parameters like lateral accelerations and yaw rate. This parameter indicates whether the saturation region of the tire is reached or not. Based on the estimate of the fire the robust decoupling control law by Ackermann [1] for active front steering is extended.
This paper describes a robust control design for automatic steering of passenger cars. Previous studies [1.2] showed that reliable automatic driving at highway speed may not be achieved under practical conditions with...
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ISBN:
(纸本)9783952426906
This paper describes a robust control design for automatic steering of passenger cars. Previous studies [1.2] showed that reliable automatic driving at highway speed may not be achieved under practical conditions with look-down reference systems which use only one sensor at the front bumper to measure the lateral displacement of the vehicle from the lane reference. An additional lateral displacement sensor is added here at the tail bumper to overcome this problem. The control design is performed stepwise: First, an initial controller is determined using the parameter space approach in an invariance plane. This controller is then refined to accomodate practical constraints. The performance and robustness of the final controller was verified experimentally at California Path.
We are proposing a supervised learning approach in robot force control which enables robot programming by human demonstration. To demonstrate the task in a intuitive way, we designed a teach device which acquires the ...
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ISBN:
(纸本)0780332148
We are proposing a supervised learning approach in robot force control which enables robot programming by human demonstration. To demonstrate the task in a intuitive way, we designed a teach device which acquires the sensorimotion of the human. The design and use of the teaching device for skill acquisition is discussed. Recording of compliant motion of the human a's shown for the ''Put Block in a Corner of a Box Problem'' land the ''Peg in Hole Problem''. Skill representation is demonstrated for the first of the two problems. Finally we are describing other useful applications of the teach device in the field of world modeling anal robotics.
Using the simulation software SIMPACK, the mechanical model of a freight car train running along a s-shaped track under high longitudinal pressure forces is presented. With the aid of simulation the freight car in the...
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ISBN:
(纸本)1853124923
Using the simulation software SIMPACK, the mechanical model of a freight car train running along a s-shaped track under high longitudinal pressure forces is presented. With the aid of simulation the freight car in the centre of the train should be judged with respect to several derailment criteria. The results are verified by comparison with measurements.
We present a resolution complete point to point path planner for up to 6 degrees of freedom (DOF) robot manipulators, based on a discretized configuration space (C-space) representation. The robot operates in an initi...
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We present a resolution complete point to point path planner for up to 6 degrees of freedom (DOF) robot manipulators, based on a discretized configuration space (C-space) representation. The robot operates in an initially known workspace (W-space). Vision integration in an easy way makes the planner capable of dealing with initially unknown obstacles. Furthermore, a Kohonen map based reorganization of the C-space increases the resolution in collision free regions of the C-space and enables path finding even for difficult paths. Experiments with low on-line computation times (lying in the order of a fraction of a second to a few seconds) demonstrate the effectiveness of the planner.
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.
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.
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