Researching ....Jekyll2020-04-11T21:36:52-04:00http://zetian.me/Zetian Zhanghttp://zetian.me/zetianzzt@gmail.com<![CDATA[Route Guidance for Satisfying Temporal Logic Specifications on Aircraft Motion]]>http://zetian.me/publications/jgcd-ltl2016-10-01T00:00:00-04:002016-10-01T00:00:00-04:00Zetian Zhanghttp://zetian.mezetianzzt@gmail.com<p><a href="../2016-jgcd-ltl.pdf"><i class="fa fa-file-pdf-o"></i> (paper)</a><br /></p>
<h3 id="authors">Authors</h3>
<p>Raghvendra V. Cowlagi, Zetian Zhang</p>
<h3 id="abstract">Abstract</h3>
<p>We present a new technique for aircraft route guidance subject to linear temporal logic (LTL) specifications. The proposed approach is based on workspace partitioning, and relies on the idea of so-called lifted graphs. Briefly, edges in a lifted graph are successions of adjacent edges in the topological graph associated with the workspace partition. We associate edges of the lifted graph with certain reachability properties of the aircraft model. The main result of this paper is the precise characterization of acceptable routes (namely, sequences of cells) that are guaranteed to be traversable by admissible state trajectories of the aircraft model while satisfying the given LTL specifications. The proposed approach incorporates nonholonomic kinematic constraints, does not require complete controllability in the presence of workspace constraints, and does not require linearization of the aircraft model. We discuss numerical methods to implement the proposed route-planning algorithm. We illustrate the proposed algorithm with numerical simulation examples that reflect the practical significance of LTL specifications in aircraft guidance.</p>
<h3 id="bibtex">Bibtex</h3>
<figure class="highlight"><pre><code class="language-html" data-lang="html">@article{cowlagi2016route,
title={Route Guidance for Satisfying Temporal Logic Specifications on Aircraft Motion},
author={Cowlagi, Raghvendra V and Zhang, Zetian},
journal={Journal of Guidance, Control, and Dynamics},
pages={1--12},
year={2016},
publisher={American Institute of Aeronautics and Astronautics}
}</code></pre></figure>
<p><a href="http://zetian.me/publications/jgcd-ltl/">Route Guidance for Satisfying Temporal Logic Specifications on Aircraft Motion</a> was originally published by Zetian Zhang at <a href="http://zetian.me">Researching ....</a> on October 01, 2016.</p><![CDATA[Motion-planning with Global Temporal Logic Specifications for Multiple Nonholonomic Robotic Vehicles]]>http://zetian.me/publications/acc-multi2016-08-01T00:00:00-04:002016-08-01T00:00:00-04:00Zetian Zhanghttp://zetian.mezetianzzt@gmail.com<p><a href="../2016-acc-zhang-cowlagi-o.pdf"><i class="fa fa-file-pdf-o"></i> (paper)</a><br /></p>
<h3 id="authors">Authors</h3>
<p>Zetian Zhang, Raghvendra V. Cowlagi</p>
<h3 id="abstract">Abstract</h3>
<p>We investigate motion-planning for a team of robotic vehicles assigned to a collaborative intelligent task in the form of global linear temporal logic (LTL) specifications. Specifically, we extend recent results from the literature to include nonholonomic kinematic constraints on the robotic vehicles. The problem formulation relies on workspace cell decompositions, where certain regions of interest in the robots’ shared workspace are defined. The proposed algorithm involves two graphs: first, the topological graph arising from the workspace cell decomposition, and second, a graph arising from vertex aggregation on the previous graph. The main technical innovation is the application of the so-called method of lifted graphs to determine the feasibility of edge transitions in these graphs. We illustrate the proposed approach with numerical simulation examples.</p>
<h3 id="bibtex">Bibtex</h3>
<figure class="highlight"><pre><code class="language-html" data-lang="html">@inproceedings{zhang2016motion,
title={Motion-planning with global temporal logic specifications for multiple nonholonomic robotic vehicles},
author={Zhang, Zetian and Cowlagi, Raghvendra V},
booktitle={American Control Conference (ACC), 2016},
pages={7098--7103},
year={2016},
organization={American Automatic Control Council (AACC)}
}</code></pre></figure>
<p><a href="http://zetian.me/publications/acc-multi/">Motion-planning with Global Temporal Logic Specifications for Multiple Nonholonomic Robotic Vehicles</a> was originally published by Zetian Zhang at <a href="http://zetian.me">Researching ....</a> on August 01, 2016.</p><![CDATA[Motion-planning with Temporal Logic Specifications for a Nonholonomic Vehicle Kinematic Model]]>http://zetian.me/publications/acc-ltl2016-07-01T00:00:00-04:002016-07-01T00:00:00-04:00Zetian Zhanghttp://zetian.mezetianzzt@gmail.com<p><a href="../2016-acc-cowlagi-zhang-o.pdf"><i class="fa fa-file-pdf-o"></i> (paper)</a><br /></p>
<h3 id="authors">Authors</h3>
<p>Raghvendra V. Cowlagi, Zetian Zhang</p>
<h3 id="abstract">Abstract</h3>
<p>We present a new technique for the control of a Nonholonomic vehicle kinematic model subject to linear temporal logic (LTL) specifications. The proposed technique is based on partitioning of the vehicle’s planar workspace into cells. The main result of this paper is the precise characterization of acceptable sequences of cells, which can be traversed by admissible state trajectory of the vehicle model while satisfying the given LTL specifications. The proposed approach does not require complete controllability of the vehicle model in the presence of workspace constraints, and no linearization of the model is involved. The key technical innovation is the so-called lifted graph. Edge transitions in the lifted graph are associated with certain forward- and backward reachable sets of the vehicle model. We discuss numerical methods to compute the aforesaid forward- and backward reachable sets of the vehicle model, and illustrate the proposed technique with numerical simulation examples.</p>
<h3 id="bibtex">Bibtex</h3>
<figure class="highlight"><pre><code class="language-html" data-lang="html">@inproceedings{cowlagi2016motion,
title={Motion-planning with linear temporal logic specifications for a nonholonomic vehicle kinematic model},
author={Cowlagi, Raghvendra V and Zhang, Zetian},
booktitle={American Control Conference (ACC), 2016},
pages={6411--6416},
year={2016},
organization={American Automatic Control Council (AACC)}
}</code></pre></figure>
<p><a href="http://zetian.me/publications/acc-ltl/">Motion-planning with Temporal Logic Specifications for a Nonholonomic Vehicle Kinematic Model</a> was originally published by Zetian Zhang at <a href="http://zetian.me">Researching ....</a> on July 01, 2016.</p><![CDATA[Incremental Path Repair in Hierarchical Motion-Planning with Dynamical Feasibility Guarantees for Mobile Robotic Vehicles]]>http://zetian.me/publications/ecc-pathrepair2015-12-01T00:00:00-05:002015-12-01T00:00:00-05:00Zetian Zhanghttp://zetian.mezetianzzt@gmail.com<p><a href="../2015-ecc-zhang-cowlagi-o.pdf"><i class="fa fa-file-pdf-o"></i> (paper)</a><br /></p>
<h3 id="authors">Authors</h3>
<p>Raghvendra V. Cowlagi, Zetian Zhang</p>
<h3 id="abstract">Abstract</h3>
<p>New requirements of autonomous mobile vehicles necessitate hierarchical motion-planning techniques that not only find a plan to satisfy high-level specifications, but also guarantee that this plan is suitable for execution under vehicle dynamical constraints. In this context, the H-cost motion-planning technique has been reported in the recent literature. We propose an incremental motion-planning algorithm based on this technique. The proposed algorithm retains the benefits of the original technique, and also significantly reduces the associated computational cost. In particular, the proposed iterative algorithm presents during intermediate iterations feasible motion-planning solutions, with the guarantee that the algorithm eventually converges to an optimal solution. Furthermore, the costs of solutions at intermediate iterations are nonincreasing except, possibly, at a finite number of special iterations. Therefore, the proposed algorithm is suitable for real-time implementations, where hard bounds on the available computation time may be imposed, and where the original H-cost optimization algorithm may not have sufficient time to converge to any solution at all. We illustrate the proposed algorithm with numerical simulation examples.</p>
<h3 id="bibtex">Bibtex</h3>
<figure class="highlight"><pre><code class="language-html" data-lang="html">@inproceedings{zhang2015incremental,
title={Incremental path repair in hierarchical motion-planning with dynamical feasibility guarantees for mobile robotic vehicles},
author={Zhang, Zetian and Cowlagi, Raghvendra V},
booktitle={Control Conference (ECC), 2015 European},
pages={2366--2371},
year={2015},
organization={IEEE}
}</code></pre></figure>
<p><a href="http://zetian.me/publications/ecc-pathrepair/">Incremental Path Repair in Hierarchical Motion-Planning with Dynamical Feasibility Guarantees for Mobile Robotic Vehicles</a> was originally published by Zetian Zhang at <a href="http://zetian.me">Researching ....</a> on December 01, 2015.</p>
