Perceiving guaranteed collision-free robot trajectories in unknown and unpredictable environments

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Vatcha, R. (2012). Perceiving guaranteed collision-free robot trajectories in unknown and unpredictable environments. Unc Charlotte Electronic Theses And Dissertations.
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Abstract

The dissertation introduces novel approaches for solving a fundamental problem: detecting a collision-free robot trajectory based on sensing in real-world environments that are mostly unknown and unpredictable, i.e., obstacle geometries and their motions are unknown. Such a collision-free trajectory must provide a guarantee of safe robot motion by accounting for robot motion uncertainty and obstacle motion uncertainty. Further, as simultaneous planning and execution of robot motion is required to navigate in such environments, the collision-free trajectory must be detected in real-time. Two novel concepts: (a) dynamic envelopes and (b) atomic obstacles, are introduced to perceive if a robot at a configuration q, at a future time t, i.e., at a point χ = (q,t) in the robot's configuration-time space (CT space), will be collision-free or not, based on sensor data generated at each sensing moment τ, in real-time. A dynamic envelope detects a collision-free region in the CT space in spite of unknown motions of obstacles. Atomic obstacles are used to represent perceived unknown obstacles in the environment at each sensing moment. The robot motion uncertainty is modeled by considering that a robot actually moves in a certain tunnel of a desired trajectory in its CT space. An approach based on dynamic envelopes is presented for detecting if a continuous tunnel of trajectories are guaranteed collision-free in an unpredictable environment, where obstacle motions are unknown. An efficient collision-checker is also developed that can perform fast real-time collision detection between a dynamic envelope and a large number of atomic obstacles in an unknown environment. The effectiveness of these methods is tested for different robots using both simulations and real-world experiments.

Details
Author

Vatcha, Rayomand

Title

Perceiving guaranteed collision-free robot trajectories in unknown and unpredictable environments

Physical Description

1 online resource (142 pages) : PDF

Date

2012

Degree Granting Institution

University of North Carolina at Charlotte

Abstract

The dissertation introduces novel approaches for solving a fundamental problem: detecting a collision-free robot trajectory based on sensing in real-world environments that are mostly unknown and unpredictable, i.e., obstacle geometries and their motions are unknown. Such a collision-free trajectory must provide a guarantee of safe robot motion by accounting for robot motion uncertainty and obstacle motion uncertainty. Further, as simultaneous planning and execution of robot motion is required to navigate in such environments, the collision-free trajectory must be detected in real-time. Two novel concepts: (a) dynamic envelopes and (b) atomic obstacles, are introduced to perceive if a robot at a configuration q, at a future time t, i.e., at a point χ = (q,t) in the robot's configuration-time space (CT space), will be collision-free or not, based on sensor data generated at each sensing moment τ, in real-time. A dynamic envelope detects a collision-free region in the CT space in spite of unknown motions of obstacles. Atomic obstacles are used to represent perceived unknown obstacles in the environment at each sensing moment. The robot motion uncertainty is modeled by considering that a robot actually moves in a certain tunnel of a desired trajectory in its CT space. An approach based on dynamic envelopes is presented for detecting if a continuous tunnel of trajectories are guaranteed collision-free in an unpredictable environment, where obstacle motions are unknown. An efficient collision-checker is also developed that can perform fast real-time collision detection between a dynamic envelope and a large number of atomic obstacles in an unknown environment. The effectiveness of these methods is tested for different robots using both simulations and real-world experiments.

Genre

doctoral dissertations

Subjects--Topics

Robotics

Degree

Ph.D.

Keywords

Collision-Free Robot Trajectory
Motion Planning
Unknown and Unpredictable Environment

Subject Area

Information Technology

Advisor(s)

Xiao, Jing

Committee Members

Akella, Srinivas
Shin, Min
Wilkinson, Barry
Xie, Jiang

Degree Note

Thesis (Ph.D.)--University of North Carolina at Charlotte, 2012.

Rights Statement

This Item is protected by copyright and/or related rights. You are free to use this Item in any way that is permitted by the copyright and related rights legislation that applies to your use. For other uses you need to obtain permission from the rights-holder(s). For additional information, see http://rightsstatements.org/page/InC/1.0/.

Rights Holder Information

Copyright is held by the author unless otherwise indicated.

Identifier

Vatcha_uncc_0694D_10379

Permalink

http://hdl.handle.net/20.500.13093/etd:351