Task-Oriented Collision Avoidance in Fixed-Base Multi-manipulator Systems

Computer simulation of sensor-based robot collision avoidance in an unknown environment

Robotica ◽

10.1017/s0263574700016313 ◽

1987 ◽

Vol 5 (4) ◽

pp. 291-302 ◽

Cited By ~ 10

Author(s):

K. Sun ◽

V. Lumelsky

Keyword(s):

Computer Simulation ◽

Motion Planning ◽

Collision Avoidance ◽

Autonomous Vehicle ◽

Planning System ◽

Robot Motion ◽

Robot Arm ◽

Fixed Base ◽

The One ◽

Robot Path

SUMMARYComputer simulation is a major tool in validation of robot motion planning systems, since, on the one hand, underlying theory of algorithms typically requires questionable assumptions and simplifications, and, on the other hand, experiments with hardware are necessarily limited by available resources and time. This is especially true when the motion planning system in question is based on sensor feedback and the generated trajectory is, therefore, unpredictable. This paper describes a simulation system ROPAS (for RObot PAth Simulation) for testing one approach — called Dynmic Path Planning (DPP) — to sensor-based robot collision avoidance in an environment with unknown obstacles. Using real time graphics animation of the motion planning system, the user can simulate the behavior of an autonomous vehicle or a robot arm manipulator with a fixed base. The overall structure of the system is described, and examples are presented.

Download Full-text

Automated Synthesis and Optimization of Robot Configurations

Volume 1A: 25th Biennial Mechanisms Conference ◽

10.1115/detc98/mech-5945 ◽

1998 ◽

Author(s):

Chris Leger ◽

John Bares

Keyword(s):

Object Oriented ◽

Control Algorithms ◽

Modular Robots ◽

Planning And Control ◽

Fixed Base ◽

Flexible Planning ◽

Key Issues ◽

Task Oriented ◽

And Control ◽

Robot Configurations

Abstract We present an extensible system for synthesizing and optimizing robot configurations. The system uses a flexible representation for robot configurations based on parameterized modules; this allows us to synthesize mobile and fixed-base robots, including robots with multiple or branching manipulators and free-flying robots. Synthesis of modular robots is also possible with our representation. We use an optimization algorithm based on genetic programming. A distributed architecture is used to spread heavy computational loads across multiple workstations. We take a task-oriented approach to synthesis in which robots are evaluated on a designer-specified task in simulation; flexible planning and control algorithms are thus required so that a wide variety of robots can be evaluated. Our system’s extensibility stems from an object-oriented software architecture that allows new modules, metrics, controllers, and tasks to be easily added. We present two example synthesis tasks: synthesis of a robotic material handler, and synthesis of an antenna pointing system for a mobile robot. We analyze several key issues raised by the experiments and show several important ways in which the system can be extended and improved.

Download Full-text

Image-based visual servoing schemes for nonholonomic mobile manipulators

Robotica ◽

10.1017/s0263574706003262 ◽

2007 ◽

Vol 25 (2) ◽

pp. 131-145 ◽

Cited By ~ 33

Author(s):

Alessandro De Luca ◽

Giuseppe Oriolo ◽

Paolo Robuffo Giordano

Keyword(s):

Visual Servoing ◽

Kinematic Model ◽

Time Derivative ◽

Interaction Matrix ◽

Mobile Manipulator ◽

Mobile Manipulators ◽

Redundancy Resolution ◽

Task Sequencing ◽

Fixed Base ◽

Task Oriented

SUMMARYWe consider the task-oriented modeling of the differential kinematics of nonholonomic mobile manipulators (NMMs). A suitable NMM Jacobian is defined that relates the available input commands to the time derivative of the task variables, and can be used to formulate and solve kinematic control problems. When the NMM is redundant with respect to the given task, we provide an extension of two well-known redundancy resolution methods for fixed-base manipulators (Projected Gradient and Task Priority) and introduce a novel technique (Task Sequencing) aimed at improving performance, e.g., avoiding singularities. The proposed methods are applied then to the specific case of image-based visual servoing, where the NMM image Jacobian combines the interaction matrix and the kinematic model of the mobile manipulator. Comparative numerical results are presented for two case studies.

Download Full-text

Representation of information in SEM by equal signal lines

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100107861 ◽

1978 ◽

Vol 36 (1) ◽

pp. 144-145

Author(s):

E. Rau ◽

N. Karelin ◽

V. Dukov ◽

M. Kolomeytsev ◽

S. Gavrikov ◽

...

Keyword(s):

Electronic System ◽

Space Distribution ◽

Specimen Surface ◽

Universal Method ◽

Base Level ◽

Signal Value ◽

Information Signal ◽

Fixed Base ◽

Scanning Line ◽

Amplitude Analyzer

There are different methods and devices for the increase of the videosignal information in SEM. For example, with the help of special pure electronic [1] and opto-electronic [2] systems equipotential areas on the specimen surface in SEM were obtained. This report generalizes quantitative universal method for space distribution representation of research specimen parameter by contour equal signal lines. The method is based on principle of comparison of information signal value with the fixed levels.Transformation image system for obtaining equal signal lines maps was developed in two versions:1)In pure electronic system [3] it is necessary to compare signal U (see Fig.1-a), which gives potential distribution on specimen surface along each scanning line with fixed base level signals εifor obtaining quantitative equipotential information on solid state surface. The amplitude analyzer-comparator gives flare sport videopulses at any fixed coordinate and any instant time when initial signal U is equal to one of the base level signals ε.

Download Full-text