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Shaping and policy search for nearest-neighbour control policies with applications to vehicle steering Alton, Ken
Abstract
The graceful animal motion we see in nature has proven extremely difficult to reproduce algorithmically. There is a need for further research into motion control techniques to address this problem adequately for computer animation and robotics applications. In this thesis, we describe a novel method for the synthesis of compact control policies for a variety of motion control problems. Direct policy search is applied to a nearest-neighbour control policy, which uses a Voronoi cell discretization of the observable state space, as induced by a set of control nodes located in this space. Such a semi-parametric representation allows for policy refinement through the adaptive addition of nodes. Thus, a coarse-to-fine policy search can be performed in such a way that the problem is shaped for easy learning. We apply our method to developing policies for steering various vehicles around a winding track. In particular, a policy is learned to steer a double-trailer truck backwards, a problem of considerable difficulty given the instability of the trailers. We also generate policies for the problems of balancing an inverted pendulum on a moving cart and driving the state of a point mass around a user-specified limit cycle. We examine these motion control results critically and discuss the limitations of the nearest-neighbour policy representation and our policy search method.
Item Metadata
Title |
Shaping and policy search for nearest-neighbour control policies with applications to vehicle steering
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Creator | |
Publisher |
University of British Columbia
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Date Issued |
2004
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Description |
The graceful animal motion we see in nature has proven extremely difficult to reproduce algorithmically. There is a need for further research into motion control techniques to address this problem adequately for computer animation and robotics applications. In this thesis, we describe a novel method for the synthesis of compact control policies for a variety of motion control problems. Direct policy search is applied to a nearest-neighbour control policy, which uses a Voronoi cell discretization of the observable state space, as induced by a set of control nodes located in this space. Such a semi-parametric representation allows for policy refinement through the adaptive addition of nodes. Thus, a coarse-to-fine policy search can be performed in such a way that the problem is shaped for easy learning. We apply our method to developing policies for steering various vehicles around a winding track. In particular, a policy is learned to steer a double-trailer truck backwards, a problem of considerable difficulty given the instability of the trailers. We also generate policies for the problems of balancing an inverted pendulum on a moving cart and driving the state of a point mass around a user-specified limit cycle. We examine these motion control results critically and discuss the limitations of the nearest-neighbour policy representation and our policy search method.
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Extent |
5695597 bytes
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Genre | |
Type | |
File Format |
application/pdf
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Language |
eng
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Date Available |
2009-12-02
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Provider |
Vancouver : University of British Columbia Library
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Rights |
For non-commercial purposes only, such as research, private study and education. Additional conditions apply, see Terms of Use https://open.library.ubc.ca/terms_of_use.
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DOI |
10.14288/1.0051749
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URI | |
Degree | |
Program | |
Affiliation | |
Degree Grantor |
University of British Columbia
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Graduation Date |
2004-11
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Campus | |
Scholarly Level |
Graduate
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Aggregated Source Repository |
DSpace
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Item Media
Item Citations and Data
Rights
For non-commercial purposes only, such as research, private study and education. Additional conditions apply, see Terms of Use https://open.library.ubc.ca/terms_of_use.