Adaptive trajectory based control for autonomous helicopters

For autonomous helicopters it is common to design a high-performance tracking controller for the attitude dynamics (innerloop) followed by a simpler, lower bandwidth design that tracks commanded position and velocity (outerloop). Separating these two designs places restrictions on the maximum bandwidth of the outerloop. This paper continues to make a conceptual separation between inner and outerloop designs, but, the final choice of compensator gains is made by treating both loops together. The controller design for both loops use feedback linearization with an adaptive element (neural network) to account for model inversion error. Pseudo Control Hedging is used to protect the adaptive element from actuator saturation nonlinearities and also from inner-outerloop interaction. The resulting control system allows position, velocity, attitude and angular rate commands. The outerloop however augments an attitude correction, that allows tracking of position and velocity in addition to attitude and angular rate.