Planar path following nonlinear controller design for an autonomous airship

Abstract

This paper investigates the planar path following control problem for an autonomous airship taking actuator saturation, actuator dynamics, parameter variation, and wind field into account. Firstly, improved nonlinear models of the airship are introduced and the control objective is formulated. Then, a command filtered backstepping controller combined with nonlinear disturbance observer is derived based on Lyapunov stability theory. The command filter is adopted to approximate the magnitude and rate saturations of actuator. The first-order inertia term is used to approximate the actuator dynamics. And, the nonlinear disturbance observer is employed to handle the disturbance caused by parameter variations and wind field. To guarantee the controller still works when saturations occur, the compensation terms are also designed. It is proved that the proposed controller can drive the airship to track a predefined path under actuator saturation, parameter variations and wind field. Besides, the proposed approach is able to avoid the complex analytic computation of command derivatives which is required in traditional backstepping method. Finally, simulations are carried out to illustrate effectiveness of the proposed controller.

Finite‐time trajectory tracking control for autonomous airships with uncertainties and external disturbances

“… , , and are the filtered signal. Remark 2 There have been some meaningful studies on second‐order command filtered backstepping control for airship [16, 29], but most of them focus on solving the problem of ‘computational explosion’. Comparing with the second‐order command filter, the third‐order command filter has better tracking accuracy.…”

“…NDOB‐based control for air vehicles is widely studied [13, 14]. NDOB‐based control for airships is also studied in [15, 16]. However, these DOB‐based control methods of airships only consider the matched disturbances such as wind disturbance.…”

Fault-tolerant path-tracking control of autonomous electric ground vehicles with lateral prescribed performance

“…In addition to self-driving techniques, the novel vehicle architecture of four-wheel independently actuated electric ground vehicles with active-steering systems has promoted the development of differential steering, active steering and fault-tolerant control (FTC) techniques (Wang and Liang, 2019; Yan et al, 2019; Zhou et al, 2019). Considering that the normal steering function loses efficiency, the additional yaw moment can be easily generated with torque differences between the left and right in-wheel (or hub) motors (Goodarzi et al, 2008; Wang et al, 2011).…”

Finite‐time spatial path following control for a robotic underactuated airship

“…However, it should be noted that the aforementioned literatures have limitations: (i) Control object of the most valuable research papers focused on the airship controller design is the fully actuated airship, see for instance [9, 10, 17]. However, for most traditional airships, they are underactuated, so these controllers will not work when the control objects are underactuated. (ii) Most of the existing works only focus on the path tracking of airships in the horizontal plane, and inflate and deflated valves are used to adjust the buoyancy of the airship in order to change the flight altitude, see for instance [1, 9, 12]. However, this scheme will result in increasing cost and reducing load capacity, so it is not suitable for those small‐dimension and low‐budget airships.…”

“…A backstepping controller combined with a wind observer was designed for the path tracking problem of the AURORA airship in [8]. Based on the nonlinear disturbance observer technique, Zhou proposed a command filtered backstepping controller for the plannar path following control of an autonomous airship [9]. Due to its insensitivity to model uncertainties and external disturbances, the sliding mode control method was applied to ZY‐01 airship [10].…”