Control of disturbed systems with measurement delays: Application to quadrotor vehicles

Disturbances and uncertainties make very difficult the control of Unmanned Aerial Vehicles (UAV). The problem is even worse, if delays are involved in the process. The uncertainty and disturbance estimator (UDE) is a technique based on the idea that the unknown dynamics and disturbances of a system can be accurately approximated by passing them through a filter with the appropriate bandwidth. This makes it very easy to design and tune a controller to deal with uncertainties and disturbances. But this solution is very sensitive to time delays. In this paper, this strategy is further developed for systems with measurement delays and hence the range of systems for which it can be applied is broadened.