Flight Dynamics Modelling and Experimental Validation for Unmanned Aerial Vehicles

Unmanned Aerial Vehicles (UAVs) are a viable alternative to manned aircraft and satellites for a variety of applications, including environmental monitoring, agriculture, and surveying. They promise greater precision and much lower operating costs than traditional methods. Critical to the success of UAV systems is the auto-pilot system which keeps the vehicle in the air and in control in the absence of a human pilot. The development of autopilot systems for UAVs is an area undergoing intense research. The ability to test autopilot systems in a virtual (software) environment using a software flight dynamics model for UAVs is significant for development. A reliable UAV simulation process which can be adapted for different aircrafts would provide a platform for developing autopilot systems with reduced dependence on expensive field trials. In many cases, testing newly developed autopilot systems in a virtual environment is the only way to guarantee absolute safety. Additionally the model would allow better repeatability in testing, with controlled flying environments. Numerical modelling of flight dynamics has a long history in the aerospace industry, and is used in the development of all modern aircraft and satellites. A flight dynamics model is a mathematical representation of the steady state performance and dynamic response that is expected of the proposed vehicle, in this case a UAV (dcb.larc.nasa.gov/Introduction/ models.html). The uses of flight dynamics models are diverse. Commercial, military, government organisations and academic sectors employ flight models to achieve their specific tasks (Chavez et al. 2001). Example applications include control algorithms testing, stability and flight characteristics evaluation of preliminary designs, onboard embedded autopilot systems, and onboard Inertial Navigation Systems (INS). In the development of UAVs and auto-pilot systems, a flight dynamics model for flight simulations allows rapid and safe testing on a computer. However, a software model developed from first principles has unknown accuracy. For such a model to be of real use, its development process is necessary to include implementation, verification and validation. The approach for each stage of the development process is presented in this chapter.