Sampled-data control of four-rotor mini quadrotor with on-line estimation of translational velocities

This paper addresses the sampled-data control problem of controlling not only all the position but also all the attitude of an underactuated quadrotor system, which is described by a set of nonlinear equations. The underactuated system is discretized by a zero order hold and a sampler. A new discrete-time state feedback controller is presented for global stabilization of the system. A time-varying discrete-time coordinate transformation is utilized to reduce the stabilization problem to a standard pole placement one for a controllable linear time-invariant discrete-time system. The design method is simple and straightforward. Moreover, an observer-based discrete-time stabilizing controller is presented without velocity measurements. Some simulations are performed to validate the effectiveness of the proposed controllers.