Dynamic mission planning for communication control in multiple unmanned aircraft teams

Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Aeronautics and Astronautics, 2012.Cataloged from PDF version of thesis.Includes bibliographical references (p. 147-160).As autonomous technologies continue to progress, teams of multiple unmanned aerial vehicles will play an increasingly important role in civilian and military applications. A multi-UAV system relies on communications to operate. Failure to communicate remotely sensed mission data to the base may render the system ineffective, and the inability to exchange command and control messages can lead to system failures. This thesis presents a unique method to control communications through distributed mission planning to engage under-utilized UAVs to serve as communication relays and to ensure that the network supports mission tasks. The distributed algorithm uses task assignment information, including task location and proposed execution time, to predict the network topology and plan support using relays. By explicitly coupling task assignment and relay creation processes the team is able to optimize the use of agents to address the needs of dynamic complex missions. The framework is designed to consider realistic network communication dynamics including path loss, stochastic fading, and information routing. The planning strategy is shown to ensure agents support both data-rate and interconnectivity bit-error- rate requirements during task execution. In addition, a method is provided for UAVs to estimate the network performance during times of uncertainty, adjust their plans to acceptable levels of risk, and adapt the planning behavior to changes in the communication environment. The system performance is verified through multiple experiments conducted in simulation. Finally, the work developed is implemented in outdoor flight testing with a team of up to four UAVs to demonstrate real-time capability and robustness to imperfections in the environment. The results validate the proposed framework, but highlight some of the challenges these systems face when operating in outdoor uncontrolled environments.by Andrew N. Kopeikin.S.M

Multi-UAV network control through dynamic task allocation: Ensuring data-rate and bit-error-rate support

A multi-UAV system relies on communications to operate. Failure to communicate remotely sensed mission data to the base may render the system ineffective, and the inability to exchange command and control messages can lead to system failures. This paper describes a unique method to control communications through distributed task allocation to engage under-utilized UAVs to serve as communication relays and to ensure that the network supports mission tasks. The distributed algorithm uses task assignment information, including task location and proposed execution time, to predict the network topology and plan support using relays. By explicitly coupling task assignment and relay creation processes the team is able to optimize the use of agents to address the needs of dynamic complex missions. The framework is designed to consider realistic network communication dynamics including path loss, stochastic fading, and information routing. The planning strategy is shown to ensure that agents support both datarate and interconnectivity bit-error-rate requirements during task execution. System performance is characterized through experiments both in simulation and in outdoor flight testing with a team of three UAVs.Aurora Flight Sciences Corp. (Fellowship Program

Autonomous Airborne Multi-Rotor UAS Delivery System

Within current combat environments, there is a demand for rapid and extremely precise re-supply missions. Typical combat airdrops require long periods of planning and can produce a large signature in an operating environment which relies on stealth for various mission sets. Team Hermes, made up of four members from the West Point graduating class of 2019, offers a new re-supply method to answer this demand. The design will allow for the delivery of a quadcopter carrying 1.5 pounds of cargo within a 5-meter radius of an impact point on the ground

Hazard Analysis for Human Supervisory Control of Multiple Unmanned Aircraft Systems

Unmanned Aircraft Systems (UAS) operations are shifting from multiple operators controlling a single-UAS to a single operator supervising multiple-UAS engaged in complex mission sets. To enable this, there is wide consensus in literature that limitations in human cognitive capacity require shifting low-level control responsibilities to automation so that human operators can focus on supervisory control. However, hazard analyses to identify related safety concerns have largely been unexplored. To address this shortfall, this paper applies System-Theoretic Process Analysis (STPA) on an abstracted model of a multi-UAS system. This hazard analysis approach handles complex systems and human-machine control interactions together. The paper describes both how to execute the analysis, and provides examples related to an operator approving or denying plans developed by the automation. Numerous traceable causal scenarios are systematically identified and generate both design recommendations and questions that must be addressed to ensure the system is designed to be safe

UAS Swarm Shares Survey Data to Expedite Coordinated Mapping of Radiation Hotspots

This study explores the capability of an Unmanned Aircraft System (UAS) swarm to locate and survey areas of interest as quickly as possible. The swarming process involves decentralized control in which UAS periodically select their respective paths after sharing information sensed in their environment. The implementation of a new swarming algorithm, Greedy Share&Seek, was found to be capable of conducting time sensitive survey missions with higher performance than a baseline algorithm without such information sharing. Numerical simulations were employed to verify the increase in performance of the algorithm in a controlled environment. In addition, the behavior was implemented on an actual UAS swarm system and successfully demonstrated in a live outdoor flight test in which the system surveyed an active radiation site using on-board sensors. This approach generally worked and demonstrated real world implementation feasibility

Towards a General-Purpose, Replicable, Swarm-Capable Unmanned Aircraft System

This paper describes an effort to create a general-purpose Unmanned Aircraft System (UAS) swarm using entirely Commercial Off-the-Shelf (COTS) parts and a reusable swarming software architecture. The software architecture used in this research was originally designed for a UAS warfare competition in 2017 called the Service Academies Swarm Challenge (SASC), hosted by the Defense Advanced Research Projects Agency (DARPA). The SASC software is a multipurpose swarm-control software architecture that allows a swarm to be tailored to many different purposes by third-parties. However, the UASs used in the original SASC competition contain custom parts which have begun to deteriorate over years of use. A COTS UAS solution using the SASC swarm architecture is the next step towards expanding the usefulness of the swarm so that it can be deployed, replicated, modified, and generalized to suit many different needs in a variety of sectors to include homeland security and defense

System-Theoretic Requirements Definition for Human Interactions on Future Rotary-Wing Aircraft

Future rotary-wing aircraft designs are highly complex, optionally manned, and include advanced teaming concepts that create unknown human-automation interaction safety risks. System-Theoretic Process Analysis (STPA) enables analysis of hazards on these complex systems. This paper demonstrates how to apply STPA in future helicopters\u27 early concept development to prevent unacceptable losses. The system is modeled as a hierarchical control structure to capture interactions between components, including human and software controllers. Unsafe control actions are identified from these relationships and are used to systematically derive causal scenarios that arise from both hazardous interactions between system components and component failures. System requirements are then generated to mitigate these scenarios. A subset of the scenarios and requirements that address human factors related concerns are highlighted. Early identification of these problems helps designers (1) refine the concept of operations and control responsibilities and (2) effectively design safety into the system