Unmanned aerial vehicles (UAVs) are used in an increasing number of applications. Such applications may include navigating through heavy traffic and highly congested airways, where numerous static and dynamic obstacles impinge upon a UAV’s flight. It is imperative that a UAV successfully avoids these obstacles, while improving its planned flight path according to certain criteria. We have modeled UAV path planning as a single objective optimization problem that utilizes a receding horizon approach, where the path is constrained to avoid obstacle collision and to account for flight aerodynamic constraints. The proposed method is gradient based, allowing for quick and robust convergence to a near optimal solution. This heuristic method converges closely to full-knowledge optimal solutions and will allow UAVs to be implemented in a greater amount of tasks and missions than before while lessening the risk to the safety of others and the safety of the UAV.

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UAV Path-Planning using Bézier Curves and a Receding Horizon Approach

Sizing of hybrid electric propulsion system for retrofitting a mid-scale aircraft using non-dominated sorting genetic algorithm

The literature reviewed in this article shows that the evolution of vehicles is in line with the evolution of animal locomotion and that it is predictable from the constructal law of design and evolution in nature. The evolution of ships and airplanes illustrates the evolutionary design of the “human-and-machine species” as it moves and spreads on Earth: farther, faster, more efficiently, and with greater lasting power (sustainability). Every vehicle size has its design. The bigger vehicle is not a magnified facsimile of the smaller. The size fraction that the lifting organs occupy in the overall vehicle increases with the body size. Every vehicle size has its niche, the supporting territory, and population to which it belongs. All the designs of movement on the globe evolve. Vehicles do not evolve by themselves; they evolve hand in glove with the humans who design and use them. The result is hierarchy, and it is why hierarchy is natural and unavoidable. We see it in geophysical movement (river basins), animal movement (food chain), human social movement (global air and maritime traffic), and everywhere else. The appearance of a new hierarchical design of movement on earth does not eliminate the existing hierarchical designs of movement. The new hierarchy joins the old, and what works is kept. No evolving system deviates from the features dictated by the law of physics of evolution in nature.

The evolution of air and maritime transport

Monocular vision based obstacle avoidance trajectory planning for Unmanned Aerial Vehicle

Here, we show that during their half-century history, helicopters have been evolving into geometrically similar architectures with surprisingly sharp correlations between dimensions, performance, and body size. For example, proportionalities emerge between body size, engine size, and the fuel load. Furthermore, the engine efficiency increases with the engine size, and the propeller radius is roughly the same as the length scale of the whole body. These trends are in accord with the constructal law, which accounts for the engine efficiency trend and the proportionality between “motor” size and body size in animals and vehicles. These body-size effects are qualitatively the same as those uncovered earlier for the evolution of aircraft. The present study adds to this theoretical body of research the evolutionary design of all technologies [A. Bejan, The Physics of Life: The Evolution of Everything (St. Martin's Press, New York, 2016)].

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The evolution of helicopters

There is a basic mismatch between the amount of power installed in small propeller-driven aircraft and that required for efficient cruising, which results from climb performance requirements. It is shown in this paper that there is a way of using excess power for most efficient cruise, the resulting airspeed coming closest to the Gabrielli-von Karman limit line of vehicular performance. A survey of 111 light aircraft was conducted, and it is found that many are operated at this optimum, while many more are not. A figure of merit is developed that measures cruise performance. Rationale is presented that is directly applicable to design for cruise efficiency.

B. H. Carson

Papers

Fuel Efficiency of Small Aircraft

Fuel efficiency of small aircraft