Random mobility models (RMMs) capture the statistical movement characteristics of mobile agents and play an important role in the evaluation and design of mobile wireless networks. Particularly, RMMs are used to model the movement of unmanned aerial vehicles (UAVs) as the platforms for airborne communication networks. In many RMMs, the movement characteristics are captured as stochastic processes constructed using two types of independent random variables. The first type describes the movement characteristics for each maneuver and the second type describes how often the maneuvers are switched. We develop a generic method to estimate RMMs that are composed of these two types of random variables. Specifically, we formulate the dynamics of movement characteristics generated by the two types of random variables as a special Jump Markov System and develop an estimation method based on the Expectation–Maximization principle. Both off-line and on-line variants of the method are developed. We apply the estimation method to the Smooth–Turn RMM developed for fixed-wing UAVs. The simulation study validates the performance of the proposed estimation method. We further conduct a UAV experimental study and apply the estimation methods to real UAV trajectories.
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Design and Characteristics of a New Transformable UAV with both Coplanar and Omnidirectional Features
To broaden and promote the applications of unmanned aerial vehicles (UAVs), UAVs with agile and omnidirectional mobility enabled by full or over actuation are a growing field of research. However, the balance of motion agility and force (energy) efficiency is challenging for a fixed UAV structure. This paper presents the new design of a transformable UAV, which can operate as a coplanar hexacopter or as an omnidirectional multirotor based on different operation modes. The UAV has 100% force efficiency for launching or landing tasks in the coplanar mode. In the omnidirectional mode, the UAV is fully actuated in the air for agile mobility in six degrees of freedom (DOFs). Models and control design are developed to characterize the motion of the transformable UAV. Simulation results are presented to validate the transformable UAV design and the enhanced UAV performance, compared with a fixed structure.
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- Award ID(s):
- 1828010
- PAR ID:
- 10432792
- Date Published:
- Journal Name:
- 2022 International Conference on Unmanned Aircraft Systems (ICUAS)
- Page Range / eLocation ID:
- 831 to 838
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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