Study of Performance of ADRC for Longitudinal Control of MAV

Abstract

Abstract Most classical control design methods are based on mathematical description of plant dynamics. However many physical plants in real world are not only nonlinear and time varying but also highly uncertain. Accurate mathematical description of physical plants are usually not available. Disturbance rejection is another issue in control design. Active Disturbance Rejection Control (ADRC) offers an inherently robust controller which requires very little information of the plant. This control algorithm actively estimates and compensates for the effects of the unknown dynamics and disturbances using extended state observer (ESO). Advantages of ESO and ADRC motivated to implement it on micro-aerial vehicle (MAV), which is highly nonlinear and prone to parametric uncertainties and disturbances while flying. This paper talks about the nonlinear control scheme for longitudinal control of MAV using ADRC. Further the gains of observer and controller are designed using bandwidth parameterization. There are mainly two contributions of this paper: design of observer and controller gains as a function of aerodynamic coefficient and airspeed of MAV and validation of robustness of control algorithm for parametric uncertainties, measurement noise and wind disturbance.