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20
Learning to Search: Structured Prediction Techniques for Imitation Learning
, 2009
"... Modern robots successfully manipulate objects, navigate rugged terrain, drive in urban settings, and play world-class chess. Unfortunately, programming these robots is challenging, timeconsuming and expensive; the parameters governing their behavior are often unintuitive, even when the desired behav ..."
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Cited by 11 (3 self)
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Modern robots successfully manipulate objects, navigate rugged terrain, drive in urban settings, and play world-class chess. Unfortunately, programming these robots is challenging, timeconsuming and expensive; the parameters governing their behavior are often unintuitive, even when the desired behavior is clear and easily demonstrated. Inspired by successful end-to-end learning systems such as neural network controlled driving platforms (Pomerleau, 1989), learning-based “programming by demonstration ” has gained currency as a method to achieve intelligent robot behavior. Unfortunately, with highly structured algorithms at their core, modern robotic systems are hard to train using classical learning techniques. Rather than redefining robot architectures to accommodate existing learning algorithms, this thesis develops learning techniques that leverage the performance of modern robotic components. We begin with a discussion of a novel imitation learning framework we call Maximum Margin Planning which automates finding a cost function for optimal planning and control algorithms such as A*. In the linear setting, this framework has firm theoretical backing in the form of strong generalization and regret bounds. Further, we have developed practical nonlinear generalizations that are effective and efficient for real-world problems. This framework reduces imitation learning
Path planning for UAVs under communication constraints using SPLAT! and MILP
- Journal of Intelligent and Robotic Systems
, 2012
"... We will in this paper address the problem of offline path planning for Unmanned Aerial Vehicles (UAVs). Our goal is to find paths that meet mission objectives, are safe with respect to collision and grounding, fuel efficient and satisfy criteria for communication. Due to the many nonconvex constrain ..."
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Cited by 5 (2 self)
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We will in this paper address the problem of offline path planning for Unmanned Aerial Vehicles (UAVs). Our goal is to find paths that meet mission objectives, are safe with respect to collision and grounding, fuel efficient and satisfy criteria for communication. Due to the many nonconvex constraints of the problem, Mixed Integer Linear Programming (MILP) will be used in finding the path. Approximate communication constraints and terrain avoidance constraints are used in the MILP formulation. To achieve more accurate prediction of the ability to communicate, the path is then analyzed in the radio propagation toolbox SPLAT!, and if the UAVs are not able to communicate according to design criteria for bandwidth, constraints are modified in the optimization problem in an iterative manner. The approach is exemplified with the following setup: The path of two UAVs are planned so they can serve as relay nodes between a target without line of sight to the base station. I.
Optimal control of nonlinear systems with temporal logic specifications
- In Proc. of the International Symposium on Robotics Research (ISRR
, 2013
"... Abstract We present a mathematical programming-based method for optimal con-trol of nonlinear systems subject to temporal logic task specifications. We specify tasks using a fragment of linear temporal logic (LTL) that allows both finite- and infinite-horizon properties to be specified, including ta ..."
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Abstract We present a mathematical programming-based method for optimal con-trol of nonlinear systems subject to temporal logic task specifications. We specify tasks using a fragment of linear temporal logic (LTL) that allows both finite- and infinite-horizon properties to be specified, including tasks such as surveillance, pe-riodic motion, repeated assembly, and environmental monitoring. Our method di-rectly encodes an LTL formula as mixed-integer linear constraints on the system variables, avoiding the computationally expensive process of creating a finite ab-straction. Our approach is efficient; for common tasks our formulation uses signifi-cantly fewer binary variables than related approaches and gives the tightest possible convex relaxation. We apply our method on piecewise affine systems and certain classes of differentially flat systems. In numerical experiments, we solve temporal logic motion planning tasks for high-dimensional (10+ continuous state) systems. 1
Learning Solutions of Similar Linear Programming Problems using Boosting Trees
, 2010
"... Abstract. In many optimization problems, similar linear programming (LP) problems occur in the nodes of the branch and bound trees that are used to solve integer (mixed or pure, deterministic or stochastic) programming problems. Similar LP problems are also found in problem domains where the objecti ..."
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Abstract. In many optimization problems, similar linear programming (LP) problems occur in the nodes of the branch and bound trees that are used to solve integer (mixed or pure, deterministic or stochastic) programming problems. Similar LP problems are also found in problem domains where the objective function and constraint coefficients vary due to uncertainties in the operating conditions. In this report, we present a regression technique for learning a set of functions that map the objec-tive function and the constraints to the decision variables of such an LP system by modifying boosting trees, an algorithm we term the Boost-LP algorithm. Matrix transformations and geometric properties of boosting trees are utilized to provide theoretical performance guarantees on the predicted values. The standard form of the loss function is altered to reduce the possibility of generating infeasible LP solutions. Experimen-tal results on three different problems, one each on scheduling, routing, and planning respectively, demonstrate the effectiveness of the Boost-LP algorithm in providing significant computational benefits over regular op-timization solvers without generating solutions that deviate appreciably from the optimum values. 1
Optimal Control of Mixed Logical Dynamical Systems with Long-Term Temporal Logic Specifications
"... Abstract—We present a mathematical programming-based method for control of large a class of nonlinear systems subject to temporal logic task specifications. We consider Mixed Logical Dynamical (MLD) systems, which include linear hybrid au-tomata, constrained linear systems, and piecewise affine syst ..."
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Abstract—We present a mathematical programming-based method for control of large a class of nonlinear systems subject to temporal logic task specifications. We consider Mixed Logical Dynamical (MLD) systems, which include linear hybrid au-tomata, constrained linear systems, and piecewise affine systems. We specify tasks using a fragment of linear temporal logic (LTL) that allows both finite- and infinite-horizon properties to be specified, including tasks such as surveillance, periodic walking, repeated assembly, and environmental monitoring. Our method directly encodes an LTL formula as mixed-integer linear constraints on the MLD system, instead of computing a finite abstraction. This approach is efficient; for common tasks the formulation may use significantly fewer binary variables than related approaches. In simulation, we solve non-trivial temporal logic motion planning tasks for high-dimensional continuous systems using our approach. I.
Discrete Path Planning Strategies for Coverage and Multi-robot Rendezvous
"... I hereby declare that I am the sole author of this thesis. This is a true copy of the thesis, including any required final revisions, as accepted by my examiners. I understand that my thesis may be made electronically available to the public. ii This thesis addresses the problem of motion planning f ..."
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I hereby declare that I am the sole author of this thesis. This is a true copy of the thesis, including any required final revisions, as accepted by my examiners. I understand that my thesis may be made electronically available to the public. ii This thesis addresses the problem of motion planning for autonomous robots, given a map and an estimate of the robot pose within it. The motion planning problem for a mobile robot can be defined as computing a trajectory in an environment from one pose to another while avoiding obstacles and optimizing some objective such as path length or travel time, subject to constraints like vehicle dynamics limitations. More complex planning problems such as multi-robot planning or complete coverage of an area can also be defined within a similar optimization structure. The computational complexity of path planning presents a considerable challenge for real-time execution with limited resources and various methods of simplifying the problem formulation by discretizing the solution space are grouped under the class of discrete planning methods. The approach suggests
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"... Abstract — Existing high-dimensional motion planning algorithms are simultaneously overpowered and underpowered. In domains sparsely populated by obstacles, the heuristics used by sampling-based planners to navigate “narrow passages ” can be needlessly complex; furthermore, additional post-processin ..."
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Abstract — Existing high-dimensional motion planning algorithms are simultaneously overpowered and underpowered. In domains sparsely populated by obstacles, the heuristics used by sampling-based planners to navigate “narrow passages ” can be needlessly complex; furthermore, additional post-processing is required to remove the jerky or extraneous motions from the paths that such planners generate. In this paper, we present CHOMP, a novel method for continuous path refinement that uses covariant gradient techniques to improve the quality of sampled trajectories. Our optimization technique converges over a wider range of input paths and is able to optimize higherorder dynamics of trajectories than previous path optimization strategies. As a result, CHOMP can be used as a standalone motion planner in many real-world planning queries. The effectiveness of our proposed method is demonstrated in manipulation planning for a 6-DOF robotic arm as well as in trajectory generation for a walking quadruped robot. I.
AUTONOMOUS UAVS Approved by:
, 2009
"... I would like to thank my advisor Dr. J.V.R. Prasad for providing me with the great opportunity to study and work on my research. I deeply appreciate him for his insightful academic advice, continuous support, and encouragement. I also thank him for being patient with my research progress. I would li ..."
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I would like to thank my advisor Dr. J.V.R. Prasad for providing me with the great opportunity to study and work on my research. I deeply appreciate him for his insightful academic advice, continuous support, and encouragement. I also thank him for being patient with my research progress. I would like to thank Dr. Daniel Schrage, Dr. Eric Johnson, Dr. Mark Costello, and Dr. Patricio Vela for serving on my thesis committee, and for giving me helpful suggestions and comments. I also thank the other faculties at Georgia Tech who offered me great lessons. I would like to express my gratitude to people I met during my Ph.D. work at Georgia Tech. In particular, I would like to thank Dr. Suresh Kannan, Dr. Ramachandra Sattigeri, and Dr. Suraj Unnikrishnan for helping me with implementation of my algorithms onto the flight system. I would like to thank my friends, Dr. Chang Chen, Dr. James Rigsby, Ivan Grill, Fahri Ersel Olcer, and An Binh Vu. I would like to thank all my Korean friends for their support and encouragement. I would like to express my special thanks to Keeryun Kang for his help and advice. I would like to give my sincere appreciation to my parents, parents-in-law, and
1 GPU Based Generation of State Transition Models Using Simulations for Unmanned Surface Vehicle Trajectory Planning
"... This document contains the draft version of the following paper: A. Thakur and S.K. Gupta. GPU based generation of state transition models using simulations for unmanned ..."
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This document contains the draft version of the following paper: A. Thakur and S.K. Gupta. GPU based generation of state transition models using simulations for unmanned
DOMAINE: STIC SPECIALITE: AUTOMATIQUE Ecole Doctorale « Sciences et Technologies de l’Information des
, 2013
"... Commande sous contraintes de systèmes dynamiques multi-agents ..."