A path following controller for model-scale helicopters

This paper addresses the problem of path following control system design for model-scale helicopters. The presented design strategy builds on the definition of an adequate generalized error space for expressing the vehicle´s dynamics and kinematics. The path following problem is cast and solved in the framework of gain scheduling control theory, using the D-methodology. The resulting control law ensures that: i) the path following system achieves zero steady state tracking error about trimming trajectories, and ii) the linearizations of the nonlinear gain scheduled feedback system and the corresponding linear designs present the same internal as well as input-output characteristics. The controller performance is evaluated in simulation, using a helicopter nonlinear dynamic model parameterized for the Vario X-treme model-scale helicopter.