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Book ChapterDOI

Real-time obstacle avoidance for manipulators and mobile robots

25 Mar 1985-Vol. 2, Iss: 1, pp 500-505
TL;DR: In this article, a real-time obstacle avoidance approach for manipulators and mobile robots based on the "artificial potential field" concept is presented, where collision avoidance, traditionally considered a high level planning problem, can be effectively distributed between different levels of control.
Abstract: This paper presents a unique real-time obstacle avoidance approach for manipulators and mobile robots based on the "artificial potential field" concept. In this approach, collision avoidance, traditionally considered a high level planning problem, can be effectively distributed between different levels of control, allowing real-time robot operations in a complex environment. We have applied this obstacle avoidance scheme to robot arm using a new approach to the general problem of real-time manipulator control. We reformulated the manipulator control problem as direct control of manipulator motion in operational space-the space in which the task is originally described-rather than as control of the task's corresponding joint space motion obtained only after geometric and kinematic transformation. This method has been implemented in the COSMOS system for a PUMA 560 robot. Using visual sensing, real-time collision avoidance demonstrations on moving obstacles have been performed.
Citations
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Journal ArticleDOI
01 Feb 1987
TL;DR: A framework for the analysis and control of manipulator systems with respect to the dynamic behavior of their end-effectors is developed, and the unified approach for motion and force control is developed.
Abstract: A framework for the analysis and control of manipulator systems with respect to the dynamic behavior of their end-effectors is developed. First, issues related to the description of end-effector tasks that involve constrained motion and active force control are discussed. The fundamentals of the operational space formulation are then presented, and the unified approach for motion and force control is developed. The extension of this formulation to redundant manipulator systems is also presented, constructing the end-effector equations of motion and describing their behavior with respect to joint forces. These results are used in the development of a new and systematic approach for dealing with the problems arising at kinematic singularities. At a singular configuration, the manipulator is treated as a mechanism that is redundant with respect to the motion of the end-effector in the subspace of operational space orthogonal to the singular direction.

2,849 citations

Journal ArticleDOI
TL;DR: A variant of the potential field method is used to produce the appropriate velocity and steering commands for the robot and demonstrates the feasibility of this approach.
Abstract: Motor schemas serve as the basic unit of behavior specifica tion for the navigation of a mobile robot. They are multiple concurrent processes that operate in conjunction with asso ciated perceptual...

1,072 citations

Journal ArticleDOI
TL;DR: This paper surveys the work on gross-motion planning, including motion planners for point robots, rigid robots, and manipulators in stationary, time-varying, constrained, and movable-object environments.
Abstract: Motion planning is one of the most important areas of robotics research. The complexity of the motion-planning problem has hindered the development of practical algorithms. This paper surveys the work on gross-motion planning, including motion planners for point robots, rigid robots, and manipulators in stationary, time-varying, constrained, and movable-object environments. The general issues in motion planning are explained. Recent approaches and their performances are briefly described, and possible future research directions are discussed.

909 citations

Proceedings ArticleDOI
13 May 1990
TL;DR: The method described, named the vector field histogram (VFH), permits the detection of unknown obstacles and avoids collisions while simultaneously steering the mobile robot toward the target.
Abstract: The method described, named the vector field histogram (VFH), permits the detection of unknown obstacles and avoids collisions while simultaneously steering the mobile robot toward the target. A VFH-controlled mobile robot maneuvers quickly and without stopping among densely cluttered obstacles. The VFH method uses a two-dimensional Cartesian histogram grid as a world model. This world model is updated continuously and in real time with range data sampled by the onboard ultrasonic range sensors. Based on the accumulated environmental data, the VFH method then computes a one-dimensional polar histogram that is constructed around the robot's momentary location. Each sector in the polar histogram holds the polar obstacle density in that direction. Finally, the algorithm selects the most suitable sector from among all polar histogram sectors with low obstacle density, and the steering of the robot is aligned with that direction. Experimental results from a mobile robot traversing a densely cluttered obstacle course at an average speed of 0.7 m/s demonstrate the power of the VFH method. >

605 citations

Journal ArticleDOI
TL;DR: The method is based on the notion of vector fields, which are used to generate desired course inputs to inner-loop attitude control laws, and vector-field path-following control laws are developed for straight-line paths and circular arcs and orbits.
Abstract: In this paper, a method for accurate path following for miniature air vehicles is developed. The method is based on the notion of vector fields, which are used to generate desired course inputs to inner-loop attitude control laws. Vector-field path-following control laws are developed for straight-line paths and circular arcs and orbits. Lyapunov stability arguments are used to demonstrate asymptotic decay of path-following errors in the presence of constant wind disturbances. Experimental flight tests have demonstrated mean path-following errors on less than one wingspan for straight-line and orbit paths and less than three wingspans for paths with frequent changes in direction.

574 citations

References
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Journal ArticleDOI
TL;DR: In this article, the authors propose an approach based on characterizing the position and orientation of an object as a single point in a configuration space, in which each coordinate represents a degree of freedom in the position or orientation of the object.
Abstract: This paper presents algorithms for computing constraints on the position of an object due to the presence of ther objects. This problem arises in applications that require choosing how to arrange or how to move objects without collisions. The approach presented here is based on characterizing the position and orientation of an object as a single point in a configuration space, in which each coordinate represents a degree of freedom in the position or orientation of the object. The configurations forbidden to this object, due to the presence of other objects, can then be characterized as regions in the configuration space, called configuration space obstacles. The paper presents algorithms for computing these configuration space obstacles when the objects are polygons or polyhedra.

1,996 citations

Book
01 Jan 1980
TL;DR: The Stanford AI Lab cart as discussed by the authors is a card-table sized mobile robot controlled remotely through a radio link, and equipped with a TV camera and transmitter equipped with an onboard TV system.
Abstract: : The Stanford AI Lab cart is a card-table sized mobile robot controlled remotely through a radio link, and equipped with a TV camera and transmitter A computer has been programmed to drive the cart through cluttered indoor and outdoor spaces, gaining its knowledge of the world entirely from images broadcast by the onboard TV system The cart uses several kinds of stereo to locate objects around it in 3D and to deduce its own motion It plans an obstacle avoiding path to a desired destination on the basis of a model built with this information The plan changes as the cart perceives new obstacles on its journey The system is reliable for short runs, but slow The cart moves one meter every ten to fifteen minutes, in lurches After rolling a meter it stops, takes some pictures and thinks about them for a long time Then it plans a new path, executes a little of it, and pauses again The program has successfully driven the cart through several 20 meter indoor courses (each taking about five hours) complex enough to necessitate three or four avoiding swerves A less successful outdoor run, in which the cart skirted two obstacles but collided with a third, was also done Harsh lighting (very bright surfaces next to very dark shadows) giving poor pictures and movement of shadows during the cart's creeping progress were major reasons for the poorer outdoor performance The action portions of these runs were filmed by computer controlled cameras (Author)

1,050 citations

Book ChapterDOI
01 Mar 1983
TL;DR: An algorithm is presented which efficiently finds good collision-free paths for convex polygonal bodies through space littered with obstacle polygons by characterizing the volume swept by a body as it is translated and rotated as a generalized cone.
Abstract: Free space is represented as a union of (possibly overlapping) generalized cones. An algorithm is presented which efficiently finds good collision-free paths for convex polygonal bodies through space littered with obstacle polygons. The paths are good in the sense that the distance of closest approach to an obstacle over the path is usually far from minimal over the class of topologically equivalent collision-free paths. The algorithm is based on characterizing the volume swept by a body as it is translated and rotated as a generalized cone, and determining under what conditions one generalized cone is a subset of another.

657 citations