Analysis of modeling techniques for low-cost actuators

Low-cost actuators are equipped on small uninhabited aerial vehicle platforms to displace the control surfaces and maneuver the aircraft. The control laws, models, and even a complete description of the actuator output are typically unavailable from the manufacturer. This is a concern because many of these aircraft are used to perform flight control research. Models of the actuator system is required in order to accurately run simulations and develop flight controls. The Unmanned Aerial Vehicle Research Group at the University of Minnesota is comparing various approaches to actuator modeling to determine which yields the appropriate fldelity level required in flight control applications. Development time may be reduced when a low fldelity model can be implemented instead of a high fldelity model. This paper compares three types of models: a black box first order equivalent system, a black box second order equivalent system, and a grey box first order equivalent system. These models were constructed based on data recorded from an actuator equipped with sensors that measure angular deflections, angular rates, back electromotive force, and current consumption. Future research will determine the best model to use for flight control research.