Review of Chosen Control Algorithms Used for Small UAV Control

In this article review of chosen control algorithms used for small UAV at Department of Control Systems of Rzeszów University of Technology and their properties is presented. At first, control laws based on modified PID algorithms are described. The example of modification is the use of double differentiation in the algorithm. Proposed modifications improve control quality. Next, model following LQR algorithms is introduced. Implementation of that algorithm improves control quality in the flight at trajectory. In the algorithm presented integration between desired trajectory and plant trajectory is introduced as an additional state.Another algorithm which is presented is sliding mode control algorithm as an example of robust control. It allows you to control plane in event of a fault. Appropriate selection of sliding surface ensures the stability of the system and good quality control under normal operating conditions and enables flight in the event of non-critical damage. To improve the quality control in emergency mode, the parameters of the sliding surface during flight can be modified. The last presented algorithm is model reference adaptive controller. The adaptation mechanism is derived from second Lyapunov method. It also enables control in the case of chosen faults. An example presented in the article is realized for roll angle control. In the case of control surface fault (e.g. aileron or rudder), the algorithm enables aircraft control. In that case control surface fault is treated as an uncertainty of model used.