6-DOF Flight Simulation Research Articles

Derivation and Flight Test Validation of Maximum Rate of Climb during Takeoff for Fixed-Wing UAV Driven by Propeller Engine

In recent years, the use of fixed-wing Unmanned Aerial Vehicles (UAVs) has expanded, and the use of fixed-wing UAVs is expected to expand due to their usefulness for long-range operations. Different from manned aircraft, no provision is required regarding climb angle at takeoff for fixed-wing UAVs. Therefore, fixed-wing UAVs can take off by taking advantage of their performance. In addition, propeller engines are the propulsion device currently used by most fixed-wing UAVs. However, the thrust force generated by a propeller engine decreases as its airspeed increases. In such circumstances, this paper describes how to derive a maximum rate of climb in which the characteristics of the propeller engine are taken into account, with the aim of reducing takeoff time by maximizing the rate of climb during takeoff. The derivation uses optimization problems with a dependency of the thrust force on the airspeed. After the derivation of the maximum rate of climb, we first checked whether the maximum rate of climb obtained for the mass system was feasible for takeoff at the rate of climb by using a 6-DOF flight simulation, and then confirmed its validity through flight experiments.

Research on Guidance and Control Law Design of Decelerating Transition and Vertical Landing for a STOVL UAV

In this paper, an integrated design method for guidance and control laws for a short takeoff and vertical landing (STOVL) unmanned aerial vehicle (UAV) during decelerating transition and vertical landing phases under thrust vector control is studied. Based on the principle of time-scale separation, the outer-loop guidance law adopts an implicit dynamic inverse method to provide attainable overload vector control instructions for decelerating transition and vertical landing phases. Meanwhile, the inner-loop control law adopts an improved eigen-structure assignment method, which tracks guidance instructions and maintains a stable attitude. The attitude nozzles are joined to the attitude control with the dropping of dynamic pressure, thereby assisting aerodynamic surfaces to stabilize attitudes. Subsequently, the feasibility and effect of the control methods for a STOVL UAV during decelerating transition and vertical landing phases are verified by a 6-DOF flight simulation platform. The simulation results demonstrate that the integrated design method is beneficial for a quick evaluation of the overall scheme.

Blended wing body lateral-directional stability investigation using 6DOF simulation

Presently at the Von Karman Institute for Fluid Dynamics, a comprehensive research investigation is being performed on the lateral-directional stability characteristics of a business jet class blended wing body. This paper presents an innovative MATLAB-based methodology using a multi-disciplinary design and optimization code written by the author, which combines various flow solvers, structural solvers, and aircraft design equations, to gain a comprehensive understanding of the overall vehicle performance while simultaneously creating a database for six-degrees-of-freedom (6DOF) flight simulation. Initial validation of the design was achieved through the Monte Carlo analysis of a 6DOF flight simulator, testing the take-off and landing flight regimes where the blended wing body is prone stall and departure due to asymmetric flow over the wing. Differential control effectors on the bottom of the wing, called “belly-flaps,” are investigated for lateral-directional control. Initial test results show that optimal span is 20% b/2, chord 20% [Formula: see text], located at 62% croot, with zero separation from vehicle centerline.

Real-time 3D flight track and flight simulation based on Google Earth

This paper proposed a novel method of real-time 3D flight track and 6-DOF flight simulation based on secondary development of Google Earth. Real-time 3D flight track and 6-DOF flight simulation, described by KML markup language, were presented by introducing real-time surveillance data of flight into Google Earth via its extendable interface. The system was built on B/S architecture, and the entire development was put on the server while the clients used Google Earth browser directly. Because there were no flight attitude in surveillance data, An algorithm to extract flight attitude from a space vector, which was connected by two pre and post track points, was proposed. The results show that 3D flight track derived by this way is simple and intuitionistic, which can be applied to the research and analysis of 3D flight track, real-time flight track and 6-DOF flight simulation.

In-Bore Yaw Effects on Lateral Throw-off and Aerodynamic Jump Behavior for Small Caliber Projectiles Firing Sidewise From Air Vehicles

The present study investigates the effects of in bore-yaw phenomenon on lateral throw-off and aerodynamic jump behavior for small caliber rotational symmetric (both in configuration and mass distribution) projectiles launched horizontally at supersonic firing speeds and various altitudes from high-subsonic air vehicles. The ammunition used is the caliber .50 API M8 bullet type firing from M2 machine automatic gun. The projectile is considered to be eccentrically engraved, tilted as it enters the rifling, and it is assumed that the tilt persists throughout its passage through the rifled barrel of the used weapon system. The modified linear 6-DOF flight simulation modeling is applied for the bullet free-flight trajectory predictions. The coupled epicyclic pitching and yawing motion analysis for the first 100 m of the examined trajectories are taken into account.

3D flight track and 6-DOF flight simulation based on Google Earth

This paper introduced a novel method of 3D flight track and 6-DOF flight simulation based on secondary development of Google Earth. 3D flight track and 6-DOF flight simulation,described by KML markup language,were presented by introducing real-time surveillance data of flight into Google Earth via its extendable interface. The system was built on B/S architecture,and the entire development was put on the server while the clients used Google Earth browser directly. An algorithm to extract flight attitude from a space vector,which was connected by two track points,was proposed. The results indicate that 3D flight track derived by this way is simple and intuitionistic,which could not only be applied to the research and analysis of 3D flight track,real-time flight track,6-DOF flight simulation,but also be used as a new query tool of flight information.