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39
Real-time visual SLAM for autonomous underwater hull inspection using visual saliency
- IEEE Transactions on Robotics
, 2013
"... Abstract—This paper reports on a real-time monocular visual simultaneous localization and mapping (SLAM) algorithm and results for its application in the area of autonomous underwater ship hull inspection. The proposed algorithm overcomes some of the specific challenges associated with underwater vi ..."
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Abstract—This paper reports on a real-time monocular visual simultaneous localization and mapping (SLAM) algorithm and results for its application in the area of autonomous underwater ship hull inspection. The proposed algorithm overcomes some of the specific challenges associated with underwater visual SLAM, namely limited field of view imagery and feature-poor regions. It does so by exploiting our SLAM navigation prior within the image registration pipeline and by being selective about which imagery is considered informative in terms of our visual SLAM map. A novel online bag-of-words measure for intra-and inter-image saliency are introduced, and are shown to be useful for image key-frame selection, information-gain based link hypothesis, and novelty detection. Results from three real-world hull inspection experiments evaluate the overall approach— including one survey comprising a 3.4 hour / 2.7 km long trajectory. Index Terms—SLAM, computer vision, marine robotics, visual saliency, information gain. I.
Progress towards multi-robot reconnaissance and the MAGIC 2010 COMPETITION
- JOURNAL OF FIELD ROBOTICS
, 2012
"... Tasks like search-and-rescue and urban reconnaissance benefit from large numbers of robots working together, but high levels of autonomy are needed in order to reduce operator requirements to practical levels. Reducing the reliance of such systems on human operators presents a number of technical ch ..."
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Cited by 12 (5 self)
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Tasks like search-and-rescue and urban reconnaissance benefit from large numbers of robots working together, but high levels of autonomy are needed in order to reduce operator requirements to practical levels. Reducing the reliance of such systems on human operators presents a number of technical challenges including automatic task allocation, global state and map estimation, robot perception, path planning, communications, and human-robot interfaces. This paper describes our 14-robot team, designed to perform urban reconnaissance missions, that won the MAGIC 2010 competition. This paper describes a variety of autonomous systems which require minimal human effort to control a large number of autonomously exploring robots. Maintaining a consistent global map, essential for autonomous planning and for giving humans situational awareness, required the development of fast loop-closing, map optimization, and communications algorithms. Key to our approach was a decoupled centralized planning architecture that allowed individual robots to execute tasks myopically, but whose behavior was coordinated centrally. In this paper, we will describe technical contributions throughout our system that played a significant role in the performance of our system. We will also present results from our system both from the competition and from subsequent quantitative evaluations, pointing out areas in which the system performed well and where interesting research problems remain.
MIRA- Middleware for Robotic Applications
"... Abstract—In this paper, we present MIRA, a new middle-ware for robotic applications. It is designed for use in real-world applications and for research and teaching. In comparison to many other existing middlewares, MIRA employs novel techniques for communication that are described in this paper. Mo ..."
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Cited by 10 (5 self)
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Abstract—In this paper, we present MIRA, a new middle-ware for robotic applications. It is designed for use in real-world applications and for research and teaching. In comparison to many other existing middlewares, MIRA employs novel techniques for communication that are described in this paper. Moreover, we present benchmarks that analyze the performance of the most commonly used middlewares ROS, Yarp, LCM, Player, Urbi, and MOOS. Using these benchmarks, we can show that MIRA outperforms the other middlewares in terms of latency and computation time. I.
Design, analysis, and learning control of a fully actuated micro wind turbine
- In Proceedings of the American Control Conference
, 2012
"... Abstract — Wind power represents one of the most promising sources of renewable energy, and improvements to wind turbine design and control can have a significant impact on energy sustainability. In this paper we make two primary contribu-tions: first, we develop and present a actuated micro wind tu ..."
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Cited by 5 (0 self)
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Abstract — Wind power represents one of the most promising sources of renewable energy, and improvements to wind turbine design and control can have a significant impact on energy sustainability. In this paper we make two primary contribu-tions: first, we develop and present a actuated micro wind turbine intended for research purposes. While most academic work on wind turbine control has largely focused on simulated evaluations, most turbine simulators are quite limited in their ability to model unsteady aerodynamic effects induced by the turbine; thus, there is a huge value to validating wind turbine control methods on a physical system, and the platform we present here makes this possible at a very low cost. The second contribution of this paper a novel policy search method, applied to optimizing power production in Region II wind speeds. Our method is similar in spirit to Reinforcement Learning approaches such as the REINFORCE algorithm, but explicitly models second order terms of the cost function and makes efficient use of past execution data. We evaluate this method on the physical turbine and show it it is able to quickly and repeatably achieve near-optimal power production within about a minute of execution time without an a priori dynamics model. I.
2012 The Authors
- Journal of Ecology 2012 British Ecological Society, Journal of Ecology
, 2000
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Magnetic Localization for Perching UAVs on Powerlines
"... Abstract — Perching on powerlines to recharge provides a unique opportunity to extend the mission duration capabilities of small-scale UAVs (Unmanned Aerial Vehicles). In this paper, we investigate the feasibility of localizing an aircraft using the magnetic field generated by a current carrying wir ..."
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Cited by 4 (2 self)
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Abstract — Perching on powerlines to recharge provides a unique opportunity to extend the mission duration capabilities of small-scale UAVs (Unmanned Aerial Vehicles). In this paper, we investigate the feasibility of localizing an aircraft using the magnetic field generated by a current carrying wire through state estimation and hardware development. By using an Extended Kalman Filter to track the real and imaginary components of the magnetic field signal, we overcome the problems posed by the field’s phase-amplitude ambiguity and demonstrate the ability to track an aircraft flying at speeds up to 8 m/s at a distance of 4 meters from the wire. We conclude that the achieved performance is adequate for controlling a bird-scale UAV in a dynamic perching maneuver and that our system would generalize to real world scenarios. I.
MPDM: Multipolicy decision-making in dynamic, uncertain environments for autonomous driving
- In Proc. IEEE Int. Conf. Robot. and Automation
, 2015
"... Abstract—Real-world autonomous driving in city traffic must cope with dynamic environments including other agents with uncertain intentions. This poses a challenging decision-making problem, e.g., deciding when to perform a passing maneuver or how to safely merge into traffic. Previous work in the l ..."
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Cited by 4 (3 self)
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Abstract—Real-world autonomous driving in city traffic must cope with dynamic environments including other agents with uncertain intentions. This poses a challenging decision-making problem, e.g., deciding when to perform a passing maneuver or how to safely merge into traffic. Previous work in the literature has typically approached the problem using ad-hoc solutions that do not consider the possible future states of other agents, and thus have difficulty scaling to complex traffic scenarios where the actions of participating agents are tightly conditioned on one another. In this paper we present multipolicy decision-making (MPDM), a decision-making algorithm that exploits knowledge from the autonomous driving domain to make decisions online for an autonomous vehicle navigating in traffic. By assuming the controlled vehicle and other traffic participants execute a policy from a set of plausible closed-loop policies at every timestep, the algorithm selects the best available policy for the controlled vehicle to execute. We perform policy election using forward simulation of both the controlled vehicle and other agents, efficiently sampling from the high-likelihood outcomes of their interactions. We then score the resulting outcomes using a user-defined cost function to accommodate different driving preferences, and select the policy with the highest score. We demonstrate the algorithm on a real-world autonomous vehicle performing passing maneuvers and in a simulated merging scenario. I.
Pushbroom Stereo for High-Speed Navigation in Cluttered Environments
"... Abstract — We present a novel stereo vision algorithm that is capable of obstacle detection on a mobile-CPU processor at 120 frames per second. Our system performs a subset of standard block-matching stereo processing, searching only for obstacles at a single depth. By using an onboard IMU and state ..."
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Abstract — We present a novel stereo vision algorithm that is capable of obstacle detection on a mobile-CPU processor at 120 frames per second. Our system performs a subset of standard block-matching stereo processing, searching only for obstacles at a single depth. By using an onboard IMU and state-estimator, we can recover the position of obstacles at all other depths, building and updating a full, local depth-map at framerate. Here, we describe both the algorithm and our implemen-tation on a high-speed, small UAV, flying at over 20 MPH (9 m/s) close to obstacles. The system requires no external sensing or computation and is, to the best of our knowledge, the first high-framerate stereo detection system running onboard a small UAV. I.
PAPER Development of a Flexible Command and Control Software Architecture for Marine Robotic Applications AUTHORS
"... The role of unmanned systems in the maritime domain continues to grow as robotic tools continue to mature and evolve, serving an increasingly ..."
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The role of unmanned systems in the maritime domain continues to grow as robotic tools continue to mature and evolve, serving an increasingly
A Hands-Off, Multi-Robot Display for Communicating Situation Awareness to Operators
"... Abstract—In this paper we introduce work toward this goal of enabling an operator to effectively maintain situation awareness over a team of heterogeneous robots. Most existing operator control units (OCUs) are designed for tele-operation of a single robot and require the constant attention of the o ..."
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Abstract—In this paper we introduce work toward this goal of enabling an operator to effectively maintain situation awareness over a team of heterogeneous robots. Most existing operator control units (OCUs) are designed for tele-operation of a single robot and require the constant attention of the operator. As the role of robots increase in important fields such as bomb disposal; intelligence, surveillance, and reconnaissance (ISR); and search and rescue it becomes critical to improve this ratio by enabling multiple robots to be monitored and controlled by a single operator. Toward this goal we have developed the Situations, Actions, Goals, and Environment (SAGE) interface, which utilizes numerous techniques for maintaining operator situation awareness by aiding the operator’s perception, comprehension, and projection when controlling a team of ground robots. Techniques that we developed include dynamic view control, event detection and prioritization, uncertainty display, view-invariant markers to make state information globally visible, and animations to avoid jarring distractions. SAGE’s interface was automated making it completely hands off, thus the operator could save interaction time for critical tasks such robot tasking. SAGE was deployed by Team Michigan as part of its OCU suite in the 2010 Multi-Autonomous Ground-robotic International Challenge (MAGIC). Team Michigan won this competition in part because of its innovative OCU designs, including SAGE, that enabled two operators to control 14 robots simultaneously – a 1-to-7 operator to robot ratio, higher than any other team. Keywords-situation awareness; robot teams; operator control unit; adaptive user interface; event detection; MAGIC I.
