Construction and modeling of a variable collective pitch coaxial UAV

Abstract

This paper describes the construction and modeling of a coaxial unmanned aerial vehicle for in-forest operation. The bare helicopter platform is upgraded and mounted with an onboard navigation system, which includes central processing units and sensors such as inertial measurement unit, camera and scanning laser range finder. The model structure of the helicopter is formulated, in which the model of rotor thrust and roll-pitch dynamics are described in details. The flapping dynamics of the rotor and the stabilizer bar are presented and lumped into a state-space model. The parameters of the state-space model are identified in frequency domain using CIFER. Time domain verification with a new set of flight data exhibits excellent agreement with the prediction of the identified model.