Enhanced funnel-control with improved performance

Abstract

This paper presents three methods to enhance a recent time-varying adaptive control strategy - funnel-control. The proportional time-varying controller is capable to control a wide range of nonlinear systems with e.g. hysteresis or dead time effects. The gain is adjusted by weighting the distance between the actual control error and the predefinable (decreasing) funnel boundary - the desired limit of the error evolution. Neither the system has to be known (only structural properties), nor has to be identified to achieve stable control results. Measurement noise is admissible. Within this publication the promising control strategy is improved triply: a) By defining the scaling function in such manner, that only an increase of the gain is allowed for more accurate and faster control performance b) By introducing a numeric and a derivative implementation of the minimal (future) distance - an online foresight for the control task, which guarantees most effective control and therefore an acceleration of the transient response at efficient use of the control input and c) By using an asymmetric funnel boundary to reduce overshoots of the output, active damping is established.