Bio-Inspired Small UAV: Nonlinear Modelling and Simulation

This research considers the development of a nonlinear model of a raven which lacks a vertical tail. The aerodynamic coefficients are obtained using the AVL (developed by MIT). The aircraft’s wings are designed to morph, thereby introducing a variable dihedral angle on the wings and creating an extra degree of freedom to control the UAV, but creating a complex and challenging modelling and control problem. Iterations and runs were conducted on AVL to acquire a comprehensive set of aerodynamic coefficients with varying dihedral angles. This set of coefficients is then implemented in SIMULINK to create the nonlinear model of the UAV. The nonlinear SIMULINK UAV model is then used to generate a family of linear models at various dihedral angles, which are subsequently used to develop an LPV model. The nonlinear and LPV models developed in this work lay a solid foundation for subsequent advanced controller designs, including the LPV-based sliding mode control with control allocation. Despite the lack of a vertical tail, this controller is robust against any uncertainties and disturbances in the input channels, including actuator faults and failures.