Fault-tolerant control for a multi-propeller airship based on adaptive sliding mode method

An airship is a kind of light-than-air vehicle, which is composed of a gas-filled cyst body and a propulsion system. The airship mainly flies in near-space, and because of the exposure to the lower temperature, solar radiation and long-term operation, it is difficult to avoid failure. Therefore, how to solve the failures of the airship and increase its safety has been a significant topic. The recent research on a fault-tolerant control system can be divided into two parts, active and passive fault-tolerant control. The active fault-tolerant control system requires a fault detection module to obtain the fault information, and then the reconfiguration control law will be reconstructed by the fault-tolerant control module. In this way, the design of the controller is very complicated and the parameters are more difficult to adjust. The passive fault-tolerant control develops a control system based on robust theory without changing the controller and system structure, which doesn’t need the fault information. In this paper, an adaptive sliding mode controller (ASMFTC) was developed for multi-propeller airship with the faults of actuators, where the external wind disturbances and control input saturation were also considered. A four-DOF dynamic model of the airship was established, and the novel fault model of the vectored propellers was designed. The fault system model of the multi-propeller airship was then built. Based on the sliding mode control theory, an integral sliding surface was presented with the residue between the trajectory and states of the airship, in order to deal with the problems of the offset faults and external disturbances, the adaptive law was designed. Thus, an adaptive sliding mode fault-tolerant control controller was proposed. The global asymptotic stability of the system is guaranteed by Lyapunov theory. The effectiveness and robustness of the controller are demonstrated by simulation results of a multi-propeller airship designed by Shanghai Jiao Tong University.