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Abstract

Unmanned Aerial Vehicles designed and manufactured often with unknown origin but available in sale of the model aircraft market rarely deals with weather circumstances and conditions defining clearances for safe air operations of the UAV. UAVs used in low-altitude flight missions are often threatened by atmospheric turbulences leading either to high angle-of-attack (AoA) or leading to the stall of the UAV. There are many mathematical models well-known and widely applied in piloted aircraft aviation when to simulate atmospheric turbulences affecting spatial motion of the aircraft. This paper targets to evaluate and simulate numerically the low-altitude air turbulences, and, to examine the vertical gust speed of the small UAV. The UAV behaviour examined numerically will support to find weather clearances ensuring UAV flight safety having the level equal or higher to that level of manned aircraft regulated well-before. A computer code in MATLAB environment is created to support numerical analysis of the small UAV behaviour in low altitude atmospheric turbulence.

A Stewart Platform as a FBW Flight Control Unit

A variety of flight control units have been put into realization for navigational purposes of spatially moving vehicles (SMV), which is mostly manipulated by 2 or 3 degrees-of-freedom (DOF) joysticks. Since motion in space consists of three translational motions in forward, side and vertical directions and three rotational motions about these axis; with present joystick interfaces, spatial vehicles has to employ more than one navigational control unit to be able to navigate on all required directions. In this study, a 3 × 3 Stewart-Platform-based FBW (Fly-By-Wire) flight control unit with force feedback is presented which will provide single point manipulation of any SMVs along three translational and about three rotational axis. Within the frame of this paper, design, capability and the advantages of the novel system is mentioned. Kinematics of a Stewart Platform (SP) mechanism employed and its motion potentials is presented by simulations and workspace of the system is evaluated. Dynamic analysis by Bond-Graph approach will be mentioned. Mechatronic design of the complete structure is discussed and force reflection capability of the system with simulations is pointed out using stiffness control. Finally, the possible future work of the subject is discussed which may include the feasible solutions of the SP in terms of size and safety when implementing inside a cockpit.

ABSTRACT

This paper presents a computational model which describes motion of an object of six degrees of freedom (DoF), intended for simulation of spatial motion of one- or two- rope-sling lifeboat or rescue boat during its launching from ship in rough sea. This is a complex model which accounts for sea conditions as well as elasticity and damping properties of davit’s elements and mechanisms, rope and boat hull. Also, are presented results of example calculations for an assumed set of technical parameters of davit and boat as well as sea conditions.

Abstract

The article presents the results of numerical simulation of a laser-guided bomb, which is dropped in calm weather conditions. The prototype of such a bomb was developed at the Air Force Institute of Technology. It was a result of the modification process of the classical training bomb. The modification consisted of building on the bomb's board a detection system to track targets that are designated by laser and a control system to adjust bomb’s glide path to precisely strike the target. In the simulation research, geometric and mass characteristics of the classical training bomb were used. Aerodynamic characteristics of the bomb have been determined using commercial software PRODAS. Using the mathematical model of the bomb spatial motion and model of the laser detection system series of simulations were performed. The main goal was to determine the effectiveness of the adopted construction solution. Therefore, simulations were performed for various initial positions of the bomb and fixed position of the target. It allowed finding the set of control laws coefficients giving the most accuracy of the bomb. The influence of structural modifications of the detection system on the possibility of effective detection and location of the target was also investigated. In the article, exemplary results of numerical calculations performed with the author's software are also shown.

Murtivariable Helicopter Flight Control Qualities Enhancement , Journal of the American Helicopter Society, Vol. 4, No. 4, 1990. [6] Gessow, A., Aerodynamics of the Helicopter , Frederick Ungar Publishing Co., New York 1985. [7] Jankowski, A., Kowalski, M., Start-up Processes’ Efficiency of Turbine Jet Engines, Journal of KONBiN, DOI 10.1515/jok-2016-0041, No. 40, pp. 63-72, 2016. [8] Jankowski, K., Physical and Mathematical Modeling of Helicopter Dynamic Spatial Motion , Ph.D. Thesis, Warsaw University of Technology, Warsaw 1982. [9] Jesaułow, S. J. et all., Helicopter

), Advanced Kalman Filtering, Least-Squares and Modelling , John Wiley & Sons. 9. Gosiewski Z., Ortyl A. (1999), Algorithms of Inertial Guidance System and the Position of the Object of Spatial Motion (in Polish), Scientific Publishers Division of the Institute of Aviation system. 10. Grewal M. S., Andrews A. P. (2008), Kalman Filtering: Theory and Practice Using MATLAB , John Wiley & Sons. 11. Haid M., Breitenbach J. (2004), Low Cost Inertial Orientation Tracking with Kalman Filter, Applied Mathematics and Computation , 153, 567-575. 12. Han S., Wang J. (2012

.” Language and spatial motion intertwine in this technology because the speech is not only a result of the motion but also the mechanism that controls it. As de Certeau pointed out, a description of a route is also the basic form of a narrative. It can thus be said that the vocal navigation system is a storytelling automaton, or, more accurately, a scriptwriting automaton coupled with a director, who reads aloud a script, which its “client” enacts as a performer. Indeed, it is a very dedicated writer, willing immediately to rewrite the script if one wishes to change