The Experts below are selected from a list of 31707 Experts worldwide ranked by ideXlab platform
Mykel J Kochenderfer - One of the best experts on this subject based on the ideXlab platform.
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Collision Avoidance for general aviation
IEEE Aerospace and Electronic Systems Magazine, 2012Co-Authors: Thomas Billingsley, Mykel J Kochenderfer, James P ChryssanthacopoulosAbstract:This presented the development and simulation of optimized Collision Avoidance logic to operate on-board general aviation aircraft. Framing the Collision Avoidance problem as a Markov decision process allows the logic to be generated using a specified encounter model and performance metrics. Past work has focused on using this framework to develop an improved Collision Avoidance system for non-GA aircraft. This presented results using the framework to optimize logic for lower performance GA aircraft and comparing its performance to the existing version of TCAS, as well as a simple Descend/Climb responsive logic. The results presented herein show that the optimized logic, issuing only climb, descend, and level-off advisories, was able to outperform the current version of TCAS and the Descend/Climb responsive logic against intruders that are equipped with TCAS. The optimized logic issuing 1000 feet = min advisories resulted in the best performance with respect to safety and alerting. For encounters where two GA aircraft are equipped with a Collision Avoidance system, the optimized logic was 3.1 times safer than TCAS for 500 feet = min advisories and 3.6 times safer for 1000 feet = min advisories. Both of the optimized methods resulted in lower probabilities of alert and reversal than TCAS and the Descend/Climb logic, which is desirable from an operational standpoint. The optimized logic that resulted in the best performance had a relatively high cost of reversing. This resulted in a very low probability of reversing for the GA aircraft, as low as zero in one case. The reversal rate for a TCAS-equipped intruder aircraft was slightly higher, but this was offset by a lower probability of strengthening advisories on the TCAS aircraft.
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next generation airborne Collision Avoidance system
2012Co-Authors: Mykel J Kochenderfer, Jessica E Holland, James P ChryssanthacopoulosAbstract:Abstract : In response to a series of midair Collisions involving commercial airliners, Lincoln Laboratory was directed by the Federal Aviation Administration in the 1970s to participate in the development of an onboard Collision Avoidance system. In its current manifestation, the Traffic Alert and Collision Avoidance System is mandated worldwide on all large aircraft and has significantly improved the safety of air travel, but major changes to the airspace planned over the coming years will require substantial modification to the system. Recently, Lincoln Laboratory has been pioneering the development of a new approach to Collision Avoidance systems that completely rethink show such systems are engineered, allowing the system to provide a higher degree of safety without interfering with normal, safe operations.
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Accounting for State Uncertainty in Collision Avoidance
Journal of Guidance Control and Dynamics, 2011Co-Authors: James P Chryssanthacopoulos, Mykel J KochenderferAbstract:An important consideration in the development of aircraft Collision Avoidance systems is how to account for state uncertainty due to sensor limitations and noise. However, many Collision Avoidance systems simply use point estimates of the state instead of leveraging the full posterior state distribution. Recently, there has been work on applying decision-theoretic methods to Collision Avoidance, but the importance of accommodating state uncertainty has not yet been well studied. This paper presents a computationally efficient framework for accounting for state uncertainty based on dynamic programming. Examination of characteristic encounters and Monte Carlo simulations demonstrates that properly handling state uncertainty rather than simply using point estimates can significantly enhance safety and improve robustness to sensor error.
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Collision Avoidance system optimization with probabilistic pilot response models
Proceedings of the 2011 American Control Conference, 2011Co-Authors: James P Chryssanthacopoulos, Mykel J KochenderferAbstract:All large transport aircraft are required to be equipped with a Collision Avoidance system that instructs pilots how to maneuver to avoid Collision with other aircraft. Uncertainty in the compliance of pilots to advisories makes designing Collision Avoidance logic challenging. Prior work has investigated formulating the problem as a Markov decision process and solving for the optimal Collision Avoidance strategy using dynamic programming. The logic was optimized to a pilot response model in which the pilot responds deterministically to all alerts. Deviation from this model during flight can degrade safety. This paper extends the methodology to include probabilistic pilot response models that capture the variability in pilot behavior in order to enhance robustness.
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Collision Avoidance for unmanned aircraft using markov decision processes
AIAA Guidance Navigation and Control Conference, 2010Co-Authors: Selim Temizer, Mykel J Kochenderfer, Leslie Pack Kaelbling, Tomas Lozanoperez, James K KucharAbstract:we investigate the automatic generation of Collision Avoidance algorithms given models of aircraft dynamics, sensor performance, and intruder behavior. By formulating the problem of Collision Avoidance as a Markov Decision Process (MDP) for sensors that provide precise localization of the intruder aircraft, or a Partially Observable Markov Decision Process (POMDP) for sensors that have positional uncertainty or limited eld-of-view constraints, generic MDP/POMDP solvers can be used to generate Avoidance strategies that optimize a cost function that balances ight-plan deviation with Collision. Experimental results demonstrate the suitability of such an approach using four dierent sensor modalities and a parametric aircraft performance model.
Peng Shi - One of the best experts on this subject based on the ideXlab platform.
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A real-time Collision Avoidance learning system for Unmanned Surface Vessels
Neurocomputing, 2016Co-Authors: Yuxin Zhao, Wang Li, Peng ShiAbstract:A great amount of effort has been devoted to the study on Unmanned Surface Vehicles (USV) due to an increasing demand for their use in a variety of maritime applications. Real-time autonomous Collision Avoidance system is the pivotal issue here, in which reliable Collision risk detection and the adoption of a plausible Collision Avoidance maneuver play a key role. Existing studies on this subject seldom integrate the COLREGS guidelines, however, and in order to ensure maritime safety, it is of fundamental importance that they should be obeyed at all times. In this paper, we presented an approach to real-time Collision Avoidance that complies with the COLREGS rules for USV. The Evidential Reasoning (ER) theory is employed to evaluate the Collision risks with obstacles encountered and trigger a prompt warning of a potential Collision. Then, we extend and adopt the optimal reciprocal Collision Avoidance (ORCA) algorithm so as to determine a Collision Avoidance maneuver that is COLREGS compliant. The proposed approach takes into consideration the fact that other obstacles also sense their surroundings and react accordingly, conforming to a practical marine situation when making a decision concerning Collision-free motion. A number of simulations have been conducted in order to confirm the validity of the theoretic results obtained.
Fabrizio Gabbiani - One of the best experts on this subject based on the ideXlab platform.
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Collision Avoidance behaviors of minimally restrained flying locusts to looming stimuli
The Journal of Experimental Biology, 2013Co-Authors: Wm R Chan, Fabrizio GabbianiAbstract:Visually guided Collision Avoidance is of paramount importance in flight, for instance to allow escape from potential predators. Yet, little is known about the types of Collision-Avoidance behaviors that may be generated by flying animals in response to an impending visual threat. We studied the behavior of minimally restrained locusts flying in a wind tunnel as they were subjected to looming stimuli presented to the side of the animal, simulating the approach of an object on a Collision course. Using high-speed movie recordings, we observed a wide variety of Collision-Avoidance behaviors including climbs and dives away from – but also towards – the stimulus. In a more restrained setting, we were able to relate kinematic parameters of the flapping wings with yaw changes in the trajectory of the animal. Asymmetric wing flapping was most strongly correlated with changes in yaw, but we also observed a substantial effect of wing deformations. Additionally, the effect of wing deformations on yaw was relatively independent of that of wing asymmetries. Thus, flying locusts exhibit a rich range of Collision-Avoidance behaviors that depend on several distinct aerodynamic characteristics of wing flapping flight.
James P Chryssanthacopoulos - One of the best experts on this subject based on the ideXlab platform.
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Collision Avoidance for general aviation
IEEE Aerospace and Electronic Systems Magazine, 2012Co-Authors: Thomas Billingsley, Mykel J Kochenderfer, James P ChryssanthacopoulosAbstract:This presented the development and simulation of optimized Collision Avoidance logic to operate on-board general aviation aircraft. Framing the Collision Avoidance problem as a Markov decision process allows the logic to be generated using a specified encounter model and performance metrics. Past work has focused on using this framework to develop an improved Collision Avoidance system for non-GA aircraft. This presented results using the framework to optimize logic for lower performance GA aircraft and comparing its performance to the existing version of TCAS, as well as a simple Descend/Climb responsive logic. The results presented herein show that the optimized logic, issuing only climb, descend, and level-off advisories, was able to outperform the current version of TCAS and the Descend/Climb responsive logic against intruders that are equipped with TCAS. The optimized logic issuing 1000 feet = min advisories resulted in the best performance with respect to safety and alerting. For encounters where two GA aircraft are equipped with a Collision Avoidance system, the optimized logic was 3.1 times safer than TCAS for 500 feet = min advisories and 3.6 times safer for 1000 feet = min advisories. Both of the optimized methods resulted in lower probabilities of alert and reversal than TCAS and the Descend/Climb logic, which is desirable from an operational standpoint. The optimized logic that resulted in the best performance had a relatively high cost of reversing. This resulted in a very low probability of reversing for the GA aircraft, as low as zero in one case. The reversal rate for a TCAS-equipped intruder aircraft was slightly higher, but this was offset by a lower probability of strengthening advisories on the TCAS aircraft.
-
next generation airborne Collision Avoidance system
2012Co-Authors: Mykel J Kochenderfer, Jessica E Holland, James P ChryssanthacopoulosAbstract:Abstract : In response to a series of midair Collisions involving commercial airliners, Lincoln Laboratory was directed by the Federal Aviation Administration in the 1970s to participate in the development of an onboard Collision Avoidance system. In its current manifestation, the Traffic Alert and Collision Avoidance System is mandated worldwide on all large aircraft and has significantly improved the safety of air travel, but major changes to the airspace planned over the coming years will require substantial modification to the system. Recently, Lincoln Laboratory has been pioneering the development of a new approach to Collision Avoidance systems that completely rethink show such systems are engineered, allowing the system to provide a higher degree of safety without interfering with normal, safe operations.
-
Accounting for State Uncertainty in Collision Avoidance
Journal of Guidance Control and Dynamics, 2011Co-Authors: James P Chryssanthacopoulos, Mykel J KochenderferAbstract:An important consideration in the development of aircraft Collision Avoidance systems is how to account for state uncertainty due to sensor limitations and noise. However, many Collision Avoidance systems simply use point estimates of the state instead of leveraging the full posterior state distribution. Recently, there has been work on applying decision-theoretic methods to Collision Avoidance, but the importance of accommodating state uncertainty has not yet been well studied. This paper presents a computationally efficient framework for accounting for state uncertainty based on dynamic programming. Examination of characteristic encounters and Monte Carlo simulations demonstrates that properly handling state uncertainty rather than simply using point estimates can significantly enhance safety and improve robustness to sensor error.
-
Collision Avoidance system optimization with probabilistic pilot response models
Proceedings of the 2011 American Control Conference, 2011Co-Authors: James P Chryssanthacopoulos, Mykel J KochenderferAbstract:All large transport aircraft are required to be equipped with a Collision Avoidance system that instructs pilots how to maneuver to avoid Collision with other aircraft. Uncertainty in the compliance of pilots to advisories makes designing Collision Avoidance logic challenging. Prior work has investigated formulating the problem as a Markov decision process and solving for the optimal Collision Avoidance strategy using dynamic programming. The logic was optimized to a pilot response model in which the pilot responds deterministically to all alerts. Deviation from this model during flight can degrade safety. This paper extends the methodology to include probabilistic pilot response models that capture the variability in pilot behavior in order to enhance robustness.
Yuxin Zhao - One of the best experts on this subject based on the ideXlab platform.
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A real-time Collision Avoidance learning system for Unmanned Surface Vessels
Neurocomputing, 2016Co-Authors: Yuxin Zhao, Wang Li, Peng ShiAbstract:A great amount of effort has been devoted to the study on Unmanned Surface Vehicles (USV) due to an increasing demand for their use in a variety of maritime applications. Real-time autonomous Collision Avoidance system is the pivotal issue here, in which reliable Collision risk detection and the adoption of a plausible Collision Avoidance maneuver play a key role. Existing studies on this subject seldom integrate the COLREGS guidelines, however, and in order to ensure maritime safety, it is of fundamental importance that they should be obeyed at all times. In this paper, we presented an approach to real-time Collision Avoidance that complies with the COLREGS rules for USV. The Evidential Reasoning (ER) theory is employed to evaluate the Collision risks with obstacles encountered and trigger a prompt warning of a potential Collision. Then, we extend and adopt the optimal reciprocal Collision Avoidance (ORCA) algorithm so as to determine a Collision Avoidance maneuver that is COLREGS compliant. The proposed approach takes into consideration the fact that other obstacles also sense their surroundings and react accordingly, conforming to a practical marine situation when making a decision concerning Collision-free motion. A number of simulations have been conducted in order to confirm the validity of the theoretic results obtained.