Uav Flight Simulation Soft Design And Validation

Along with the rapid development of computer technology, microelectronics, materials and communications, UAVs (Unmanned Aerial Vehicle) are increasingly used in both civil and military fields. This paper is on the development of an UAV Flight Simulation Software, which can be applied in UAV flight simulation and verification of route tracking, as well as a certain type of UAV Flight Control Algorithm and simulation tests of navigation algorithm. The main contents are as follows:1,mathematical model of UAV are established and corresponding software modules are formulatedA simulation database through the UAV flight test curve is built, which is the basis of the flight simulation system. Detailed and accurate raw simulation data are the fundamental guarantee of the flight simulation system. On one hand, the realness degree of the flight simulation system depends on the accuracy degree of the mathematical models for various modules; on the other hand, it also depends on the detail of the raw data of the simulated objects. The more detailed the raw data are, the more accurate the simulation system would be established on the basis of an accurate mathematical model. In this simulation system, we create a database to store and manage the raw data, and ensure efficient call of the raw data to the simulation program.Various engineering calculation formula of the aerodynamic coefficients are derived, which is key to get aerodynamic force and aero-dynamical moment. This software adopts original test flight curve and tunnel data in calculation of the aerodynamic coefficient of aircraft. One-dimensional interpolation algorithm and two-dimensional interpolation algorithm are used for aerodynamic coefficients.Six-freedom-degree equations of motion of the aircraft has been deduced theoretically in order to overcome singularity when transform coordinate through Eulerian approach and make bigger aircraft maneuver, the software uses four element method for solving equations; In order to ensure simulation precision and taking into account the speed of simulation, it uses Four-order-Runge-Kutta method to solve differential equations.The mathematical model of atmosphere and the engine model are built, and the computational procedure of the atmosphere data can be derived through temperature, pressure, density and other parameters of the atmosphere, as well as the variation of temperature with height. The software simulation engine is based on the overall performance of the engine simulation, and can not simulate on the various components of the engine model. Simulation Principle: According to the available experimental data, under required speed, using thrust as the main performance parameter and throttle command as an input parameter, the aircraft altitude and flight speed are major factors in affecting the thrust of a throttle command. Seek corresponding engine throttle rod thrust through interpolation function in a specific height and speed.2. UAV autonomous navigation algorithm design and software realizationTo propose a program suitable for UAV level autonomous navigation, the program is as follows: Set UAV turning starting point and end-point. UAV pass through each setting navigation point by the way of pressure airline. There are only two kinds of connection between adjacent navigation point, straight line and circular. This program avoid severe shake when make a turn in advance or transform air line, and meet the specification of autonomous flight of UAV.To realize autonomous flight control at each waypoint and draft data structure of waypoint, the draft data of waypoint should include: waypoint number, waypoint location, the way flight passing through the waypoint, the flight characteristic of the waypoint and engine accelerator command etc.UAV autonomous navigation system simulation module and navigation information solver module are built, and corresponding software is prepared.3. Digital Map Design. Digital map is an indispensable part of Flight Simulation software. In the simulation software, based on dynamic memory technology, digital map module are produced, the module's main function is to construct accurate digital maps for the aircraft including maps of cities, mountains, waters, roads, railways, boundaries as well as latitude and longitude lines etc. The map shows the planmetric route of aircraft flight, and providing a basis for planning routes to achieve the scheduled routes and actual visual display of digital simulation routes on the map.4. UAV flight control systems are designed and corresponding software modules are developed. One function of the flight control system is to make sure the flight quality of aircraft throughout the whole flight envelop. The other function is, according to the established flight route data, to control the aircraft to complete three categories of tactical maneuvers within the maneuver range of the aircraft, including climb or dive maneuver flight, horizontal turning flight and climbing turn maneuver, or diving turn maneuvering. In this way, the scheduled flight routes of aircraft can be followed and the designed flight missions are set. Flight control system consists of longitudinal control system and lateral control system. The controller adopts proportional-integral, the proportion parameters of the control law vary with dynamic and static pressure of the aircraft automatically. The function of the flight control system software can be achieved by a CaircraftControlSyst.5. Flight parameter data record. Flight parameters can be recorded and stored during the flight simulation process of an unmanned aircraft in through simulation software. Flight parameter data will be recorded in each 40 milliseconds so that a flight process and performance can be analyzed and evaluated.6. On the completion of the flight simulation software, the final step is to validate the accuracy of the aircraft model and the practicability of simulation software. This can be done by analyzing and comparing obtained flight parameter data after setting track, making plans for flight missions, and conducting mission flight simulation under the control of automatic flight control system. In this way, the capacity of the UAV in terms of fulfilling various missions and tracking the scheduled routes.Software simulation work is divided into two parts. One is the simulation validation of aircraft dynamic model through three waypoints. The routes include level-off, horizontal bend, and climbing. By analysis of the flying parameters, that the aircraft model in flight simulation software accords with the dynamic model of a certain type of aircraft can be proved. Then tracking simulation of the routes is carried out. The results show the aircraft in 3-dimentional space can better follow the planned route, which indicates that the navigation control module has good navigation control effect.