A framework for characterization and planning of safe, comfortable, and customizable motion of assistive mobile robots


A framework for characterization and planning of safe, comfortable, and customizable motion of assistive mobile robots

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dc.contributor.advisor Longoria, Raul G.
dc.contributor.advisor Kuipers, Benjamin
dc.creator Gulati, Shilpa
dc.date.accessioned 2011-10-26T16:12:38Z
dc.date.available 2011-10-26T16:12:38Z
dc.date.created 2011-08
dc.date.issued 2011-10-26
dc.date.submitted August 2011
dc.identifier.uri http://hdl.handle.net/2152/ETD-UT-2011-08-3992
dc.description.abstract Assistive mobile robots, such as intelligent wheelchairs, that can navigate autonomously in response to high level commands from a user can greatly benefit people with cognitive and physical disabilities by increasing their mobility. In this work, we address the problem of safe, comfortable, and customizable motion planning of such assistive mobile robots. We recognize that for an assistive robot to be acceptable to human users, its motion should be safe and comfortable. Further, different users should be able to customize the motion according to their comfort. We formalize the notion of motion comfort as a discomfort measure that can be minimized to compute comfortable trajectories, and identify several properties that a trajectory must have for the motion to be comfortable. We develop a motion planning framework for planning safe, comfortable, and customizable trajectories in small-scale space. This framework removes the limitations of existing methods for planning motion of a wheeled mobile robot moving on a plane, none of which can compute trajectories with all the properties necessary for comfort. We formulate a discomfort cost functional as a weighted sum of total travel time, time integral of squared tangential jerk, and time integral of squared normal jerk. We then define the problem of safe and comfortable motion planning as that of minimizing this discomfort such that the trajectories satisfy boundary conditions on configuration and its higher derivatives, avoid obstacles, and satisfy constraints on curvature, speed, and acceleration. This description is transformed into a precise mathematical problem statement using a general nonlinear constrained optimization approach. The main idea is to formulate a well-posed infinite-dimensional optimization problem and use a conforming finite-element discretization to transform it into a finite-dimensional problem for a numerical solution. We also outline a method by which a user may customize the motion and present some guidelines for conducting human user studies to validate or refine the discomfort measure presented in this work. Results show that our framework is capable of reliably planning trajectories that have all the properties necessary for comfort. We believe that our work is an important first step in developing autonomous assistive robots that are acceptable to human users.
dc.format.mimetype application/pdf
dc.language.iso eng
dc.subject Assistive robots
dc.subject Robot motion planning
dc.subject Safe and comfortable motion planning for wheeled mobile robots
dc.title A framework for characterization and planning of safe, comfortable, and customizable motion of assistive mobile robots
dc.date.updated 2011-10-26T16:12:55Z
dc.identifier.slug 2152/ETD-UT-2011-08-3992
dc.contributor.committeeMember Djurdjanovic, Dragan
dc.contributor.committeeMember Sreenivasan, S.V.
dc.contributor.committeeMember Stone, Peter
dc.description.department Mechanical Engineering
dc.type.genre thesis
dc.type.material text
thesis.degree.department Mechanical Engineering
thesis.degree.discipline Mechanical Engineering
thesis.degree.grantor University of Texas at Austin
thesis.degree.level Doctoral
thesis.degree.name Doctor of Philosophy

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