Nonlinear Disturbance Observer-Based Standoff Target Tracking for Small Fixed-Wing UAVs

Information-Based Sensor Control for Multitask Planning via Multi-Bernoulli Filter

“…For example, a single sensor, controlling its position, velocity, and course, may affect the estimation accuracy of multitarget tracking in which not only the number of targets changes over time but also the measurements are confronted with missed detections and false alarms. In essence, sensor control is an optimal nonlinear control problem [1]. e solution to such problems is usually in the framework of partially observable Markov decision process (POMDP) [2][3][4].…”

Finite‐time disturbance observer‐based modified super‐twisting algorithm for systems with mismatched disturbances: Application to fixed‐wing UAVs under wind disturbances

“…In recent years, there have been various applications of disturbance observer-based control (DOBC) to the path following mission of fixed-wing UAVs. [17][18][19][20][21][22] With regard to this control objective, the fixed-wing UAV is required to travel on some predefined geometric paths, in which the UAV does not need to arrive at a specific location in a pre-specified time as in the trajectory tracking control objective. 21,22 When the fixed-wing UAV works for the path following task, it provides many attractive features including operating at a constant airspeed, consuming reasonable energy, and reducing the difficulty for control design.…”

“…Then, the estimated wind disturbances were integrated into the nominal path following controller, which ensures the asymptotic stability of the overall system. Besides, Shin et al 20 considered the (path following) stand-off target tracking control problem of the fixed-wing UAV by appropriately incorporating the disturbance observer and the Lyapunov guidance vector field (LGVF). In particular, the disturbance observer is applied to estimate the wind disturbances and the LGVF is designed to mitigate the effects of the wind and to follow the ground target.…”

“…In particular, the disturbance observer is applied to estimate the wind disturbances and the LGVF is designed to mitigate the effects of the wind and to follow the ground target. Various simulation results were provided in the works of Liu et al 17 and Shin et al 20 to show the effectiveness of the proposed control schemes. However, there are two main drawbacks of these approaches: (i) the disturbance observers being incorporated with the corresponding guidance control laws in Liu et al 17 and Shin et al 20 can only work with slowly time-varying wind disturbances; and (ii) the proposed control schemes in Liu et al 17 only ensures the asymptotic stability of the closed-loop system, which may not provide the fast convergence rate and the high control accuracy features of the controlled output.…”

“…(i) most of the existing PFC approaches for fixed-wing UAVs only ensure the asymptotic stability of the closed-loop system, [17][18][19]21 whereas our proposed FDO-ST-PFC guarantees that the system output is able to track the desired geometric paths in finite time; (ii) in comparison with the disturbance observers being incorporated in the PFC schemes by the works of Liu et al 17 and Shin et al 20 the proposed disturbance observer in the FDO-ST-PFC relaxes the slow-varying assumption on the wind disturbances; and (iii) the faster disturbance estimation convergence rate is obtained with the proposed disturbance observer in the FDO-ST-PFC, compared with the existing disturbance observer being incorporated in the finite-time guidance control law by the work of Yu et al 22 The rest of this article is organized as follows. System description and some useful lemmas are presented in Section 2.…”