Robust control of UAV coaxial rotor by using exact feedback linearization and PI-observer

Dynamic observer‐basedH∞ robust control for a ducted coaxial‐rotor UAV

“…• A PI-observer based robust control of coaxial rotor UAV is designed in [20]. The method guarantees convergence of the coaxial rotor UAV to a given reference trajectory in spite of disturbances, whereas the model uncertainties and sensing noise are not considered.…”

“…Remark The dynamics modelling of constant crosswind disturbance is carried out and added to the whole DCUAV model to design the proposed control algorithm. Compared with the control design method without disturbance modelling [9, 20], this helps to improve the suppression effect of the control method on directional constant crosswind. The disturbance state space description matrix obtained in this paper is a linear matrix space with wind velocity as a first‐order variable.…”

“…$${T_{\omega z}}\ $$represents the transfer function from the disturbances $$\omega ( t )$$ to the performance output $$z( t )$$ and γ is a given positive scalar. Remark The similar dynamic observer‐based controller structure has been considered in existing methods in the literature [21–26], the dynamic observer can be considered as an extension of the usual observer in its configuration. Compared with static observer‐based control method [16, 20, 33] the dynamic observer provides more freedom for meeting the trade‐off between different design specifications. In this paper, the main efforts have been made on exploring the potential benefits of dynamic observer for the DCUAV model uncertainties and external disturbances suppression issue.…”

“…In this section, the proposed control strategy has been tested by simulation in order to check the effectiveness and the performance attained for the DCUAV attitude stabilization and reference tracking problem in the presence of system time‐varying uncertainties and external disturbances. The simulation results are compared with the existing methods in the literature detailed below: A PI‐observer based robust control of coaxial rotor UAV is designed in [20]. The method guarantees convergence of the coaxial rotor UAV to a given reference trajectory in spite of disturbances, whereas the model uncertainties and sensing noise are not considered. A disturbance observer based hierarchical control is proposed in [16] to deal with the tracking problem of an underactuated coaxial‐rotor UAV in the presence of unknown aerodynamic efforts and sensing noise. …”

“…The work in [19] presented a sliding mode disturbance observer-based controller design for a two-rotor helicopter. In [20], a non-linear trajectory tracking control method for a coaxial rotor UAV is developed based on PI-observer. Due to the simple linear structure of the PI-observer, the non-linear robust control method can be applied to the coaxial rotor system, which is dynamically unstable.…”