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Dynamic Modelling and Tracking Control of Nonholonomic Wheeled Vehicles

IFAC Proceedings Volumes 1993年第2期26卷 61-64页

作者： G.J. Pappas K.J. Kyriakopoulos New York State Center for Advanced Technology in Automation and Robotics & Electrical Computer and Systems Engineering Department Rensselaer Polytechnic Institute Troy NY 12180-3590 USA

Nonholonomic vehicles are shown to be kinematically equivalent to unicycles. A dynamic model for mobile vehicles moving on planar surfaces under nonholonomic constraints is derived. The model is decomposed into a kinematic and a dynamic subsystem. The kinematic subsystem is shown to be globally stabilizable by using continuous control laws on reference trajectories that are nonstationary and continuously differentiable with respect to time. The continuity of the kinematic control inputs allows the extension of the vehicle control at the dynamic level. Stability of the overall closed loop system is examined using singular perturbation theory. Simulations verify all theoretical derivations.

关键词： Nonholonomic Control Vehicle Control Mobile Robots

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Registration of dissimilar featureless models for inspection

Registration of dissimilar featureless models for inspection

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IEEE International Conference on robotics and Automation (ICRA)

作者： G.H. Tarbox S.N. Gottschlich L.A. Gerhardt New York State Center for Advanced Technology in Automation and Robotics and Electrical Computer and Systems Engineering Department Rensselaer Polytechnic Institute Troy NY USA

General-purpose CAD-based inspection of a manufactured workpiece often involves comparing a part model created using intensity or range images of the part to a toleranced reference model of the part. Before this comparison can be made, however, the sensed object model must be registered to the reference object model. Most registration approaches assume that it is possible to identify and match features in the models and that the object models represent very similar geometries. A registration approach that deals with featureless dissimilar models is presented, and experimental results are demonstrated. Although the need for such an approach was motivated by needs in inspection, the approach is very general and can be used in a variety of other applications.< >

关键词： Inspection Casting robotics and automation Solid modeling Data structures systems engineering and theory Geometry Valves Manufacturing processes Surface morphology

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Shape matching from grasp using a minimal representation size criterion

Shape matching from grasp using a minimal representation siz...

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IEEE International Conference on robotics and Automation (ICRA)

作者： R. Joshi A.C. Sanderson New York Center for Advanced Technology in Automation and Robotics USA Electrical Computer and Systems engineering Department Rensselaer Polytechnic Institute Troy NY USA

A robust polynomial-time algorithm for model-based pose estimation from tactile grasp data is presented. A minimal representation criterion is used to formulate the matching problem as a global optimization. The hypothesize-and-test paradigm is invoked to search for the optimal solution. A three-on-three match of model features to data features is used to reduce the transform search space to polynomial size. A polynomial-time assignment algorithm is used to compute the optimal correspondence for each hypothesized pose. The strength of the algorithm lies in its ability to perform with noisy or incomplete data and with missing or spurious features. It is capable of rejecting outliers and finding partial matches, and it produces sensible results even in the presence of large noise. The algorithm has been implemented and tested on actual data.< >

关键词： Shape Polynomials robotics and automation Testing Robustness Kinematics Least squares approximation Fingers Data engineering systems engineering and theory

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Nonholonomic path planning with inequality constraints

Nonholonomic path planning with inequality constraints

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IEEE Conference on Decision and Control

作者： A.W. Divelbiss J. Wen New York State Center for Advanced Technology in Robotics and Automation Department of Electrical Computer and Systems Engineering Rensselaer Polytechnic Institute Troy NY USA

A class of Newton-type algorithms is effective in solving the kinematic path planning problem for a system with nonholonomic equality constraints. A key result in this approach has been the generic full rank condition of a certain gradient operator. We have extended this method to path planning problems with inequality constraints and shown its efficacy in solving some challenging problems, but a similar genericity result is not currently available. In this paper, we present some extension of our algorithm for nonholonomic path planning with equality and inequality constraints and show the generic full rank condition for a special case. Simulation examples involving a steerable tractor-trailer vehicle and experiment results of a quarter-scale car with a trailer are presented.< >

关键词： Path planning Control systems Nonlinear control systems Controllability robotics and automation systems engineering and theory Kinematics Space vehicles Velocity control Nonlinear systems

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Automatic synthesis and verification of compliance mappings

Automatic synthesis and verification of compliance mappings

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IEEE International Conference on robotics and Automation (ICRA)

作者： S. Vougioukas S. Gottschlich New York State Center for Advanced Technology in Robotics and Automation USA Electrical Computer and Systems Engineering Department Rensselaer Polytechnic Institute NY USA

When the uncertainty is large compared to clearances between objects, some form of compliance is required for a robot to manipulate these objects. Such situations include, but are not restricted to, assembly operations. Compliance can be thought of as a task-dependent mapping from sensed forces to corrective motions which bring the robot closer to its goal. A methodology for the automated synthesis of this mapping is described. The possible erroneous configurations of the robot together with their resulting contact forces are computed, and a corrective motion is identified for each configuration. The validity of the mapping is checked to ensure that the sensed forces will provide unambiguous information during the actual execution of the planned compliant motion.< >

关键词： robotics and automation Robot sensing systems Uncertainty Robotic assembly Path planning Motion planning Damping systems engineering and theory Technology planning Sensor systems

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Using an active vision system to compute time-until-impact

Using an active vision system to compute time-until-impact

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International Conference on Industrial Electronics, Control and Instrumentation

作者： J. Dias J. Batista H. Araujo A.T. de Almeida Institute of Systems and Robotics Department of Electrical Engineering University of Coimbra Coimbra Portugal Universidade de Coimbra Coimbra Coimbra PT Dept. of Electr. Eng. Coimbra Univ. Portugal

Describes the use of an experimental system for active vision to compute time-until-impact. The time-until-impact is evaluated by using the principle of the human visual fixation process. The mechanical system enables the positioning of the cameras' support platform by means of three rotational degrees of freedom and also the control of the vergence angle of each camera. The motors used are stepper motors which are controlled by a system specifically designed and built for this purpose. Each camera's lens has three degrees of freedom, corresponding to zoom, focus and aperture. All the control system electronics as well as the system status data acquisition electronics are integrated in a single control unit. This control unit is connected to a system responsible for the active vision system motion generation.< >

关键词： Machine vision Computer vision Control systems Cameras Humans Mechanical systems Lenses Apertures Data acquisition Motion control

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Autonomous vision-based technology for AVCS

Autonomous vision-based technology for AVCS

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IEEE Conference on Vehicular Technology (VTC)

作者： J.R. Bishop M. Juberts D. Raviv IVHS Research Division U.S. Department of Transportation Federal Highway Administration Robot Systems Division Department of Commerce National Institute for Standards and Technology USA The Robotics Center Electrical Engineering Department Florida Atlantic University USA

A brief description of the advanced vehicle control systems (AVCSs) component of the intelligent vehicle/highway system (IVHS) program is given. The AVCS goals and plans, which, if implemented, could vastly increase highway capacity and safety, are described. A description of the latest work at the National institute of Standards and Technology (NIST) and Florida Atlantic University (FAU) on applying vision-based technology to autonomous driving is given. The testbed vehicle performs autonomous road following on a test course at speeds of up to 90 km/hour under various weather and outdoor light conditions. The vision processing and control algorithms used are described, together with the conditions under which the vehicle has been tested. A brief description of the next phase of development, already in progress, is provided.

关键词： Automatic voltage control Remotely operated vehicles Testing Intelligent vehicles Road vehicles Road transportation Road safety NIST Control systems Capacity planning

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A kalman filter‐based technique for combined digital estimation of voltage flicker and phasor in power distribution systems

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European Transactions on electrical Power 1993年第2期3卷 131-142页

作者： Kamwa, I. Srinivasan, K. Dr. Innocent Kamwa (1960) has been with the Hydro-Quebec Research Institute (IREQ) since 1988. He is also an. Associate Professor of Electrical Engineering at Laval University Quebec/PQ/Canada. His current interests are broadly in the areas of system identification synchronous machine developments and real-time control and monitoring of electric power systems. He received his B.Eng. and Ph.D. degrees in electrical engineering from the Laval University in 1984 and 1988 respectively. He is a member of the IEEE Power Engineering and Control System Societies and is registered professional engineer in Quebec. (Institut de Recherche d'Hydro-Quebec (IREQ) 1800 Montie Ste-Julie Varennes Canada J3X 1S1 T +514/652-8121 Fax + 514/652-8005) Dr. Krishnaswamy Srinivasan (1943) received his BSc. (Physics University of Delhi/India) in 1962 B.E. (Electrical Engineering) I.I.Sc. in 1965 M.A.Sc. (Power Systems) in 1967 and Ph.D. (Automatic Control) in 1970 from the University of Waterloo/Canada. He is with the Hydro-Quebec utility's Reasearch centre (IREQ) since 1972. His current interests are in micro-computers estimation and control applications in power systems. He is a member of IEEE Power and Automatic Control Societies and is a registered professional engineer in Quebec. (Institut de Recherche d'Hydro-Québec (IREQ) 1800 Montéé Ste-Julie Varennes Canada. J3X 1S1 T +514/652-6250 Fax +514/652-8005)

Electric power quality is of prime importance when sensitive electronic equipment is involved. One of the aspects of power quality is known as flicker level. The present paper proposes an algorithm for real‐time monitoring of voltage flicker based on the Kalman filtering technique. First a stochastic state space model of the system voltage with a linear time‐invariant transition matrix has been established, yet non‐linear in the scalar observation model. Using noisy measurements of a single‐phase voltage, an extended Kalman filter leads to instantaneous value of rms voltage and phase. Then the flicker level has been derived by appropriate filtering and statistical processing on short records of the rms voltage measurements. Simulated and actual data demonstrating the effectiveness of the overall scheme in estimating voltage phasor and flicker for a wide range of swing frequencies are presented and discussed. Among the several power system applications of the new stochastic observer considered, a remote load control concept based on the carrier amplitude modulation is shown being possible and included are test results confirming the filter capability to retrieve sequences of amplitude‐modulated bit patterns travelling through the power line to customer sites. Copyright © 1993 John Wiley & Sons, Ltd.

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OFFLINE TRACING AND REPRESENTATION OF SIGNATURES

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IEEE TRANSACTIONS ON systems MAN AND CYBERNETICS 1992年第4期22卷 755-771页

作者： LEE, S PAN, JC Institute for Robotics and Intelligence Systems in the Department of Electrical Engineering-Systems University of Southern California Los Angeles CA USA

A new approach to the representation of signatures in an offline environment is presented. The approach makes a tracing of a signature similar to the way a human normally does and incorporates the dynamic information of the tracing sequence into the representation of the signature. Tracing involves hierarchical decision-making for stroke identification and ordering based on a set of heuristic rules. These heuristic rules work as operators that transform a two-dimensional (2-D) spatial pattern into a one-dimensional (1-D) temporal pattern, thus making it possible to extract the dynamic features of a signature. Following the stroke sequence of a signature identified by the tracing, a multiresolution critical-point segmentation method is proposed to extract local feature points, at varying degrees of scale and coarseness, for representation. Finally, to make the representation translation-, rotation-, and scaling-invariant, a critical-point normalization method is introduced. Experimental results are shown.

关键词： Character recognition Handwriting recognition Feature extraction Humans Text recognition Intelligent robots Lifting equipment Decision making Two dimensional displays Spatial resolution

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STRUCTURAL INDEXING - EFFICIENT 2-D OBJECT RECOGNITION

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IEEE TRANSACTIONS ON PATTERN ANALYSIS AND MACHINE INTELLIGENCE 1992年第12期14卷 1198-1204页

作者： STEIN, F MEDIONI, G Institute for Robotics and Intelligent Systems Department of Electrical Engineering University of Southern California Los Angeles CA USA

We address the problem of recognition of multiple flat objects in a cluttered environment from an arbitrary viewpoint. The models are acquired automatically and approximated by polygons with multiple line tolerances for robustness. Groups of consecutive segments (super segments) are then encoded and entered into a table. This provides the essential mechanism for indexing and fast retrieval. Once the database of all models is built, the recognition proceeds by segmenting the scene into a polygonal approximation;the code for each super segment retrieves model hypotheses from the table. Hypotheses are clustered if they are mutually consistent and represent the instance of a model. Finally, the estimate of the transformation is refined. This methodology allows us to recognize models in the presence of noise, occlusion, scale, rotation, translation, and a restricted range of weak perspective. We show that the complexity can be bounded by O(n) less-than-or-equal-to O(recognition) less-than-or-equal-to O(n2 . m3), where n is the number of features in the scene, and m is the number of models in the database.

关键词： Structural Indexing Consecutive Segment Groups Scene Segmentation Scale Insensitivity Rotation Insensitivity Translation Insensitivity Efficient 2 D Object Recognition Multiple Flat Objects Cluttered Environment Multiple Line Tolerances Robustness Super Segments Database Polygonal Approximation Noise Occlusion Weak Perspective Complexity Bound Computational Complexity Database Management systems Image Recognition Image Segmentation

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