Engine speed and velocity controller development for small unmanned aerial vehicles

The Remotely Piloted Vehicle and Micro-Satellite Research Laboratory (MARL) has designed a velocity controller for the surveillance, watch, autonomous, and navigation (SWAN) unmanned aerial vehicle (UAV). Nonlinear and linear models of the engine were derived to perform the task and the velocity controller was designed on the basis of the linear model. The nonlinear model was used to perform simulation, before implementing the velocity controller on the SWAN UAV. The outer loop of the velocity controller calculates the difference between the desired airspeed, the existing airspeed, and determines the desired engine speed. The inner loop of the controller calculates the difference between the desired engine speed and the existing engine speed. The inner loop is a feedback control that uses throttle, to control engine speed, while the outer loop is a feedback control that uses engine speed to control velocity.