10.24425/acs.2022.141716
Archives of Control Sciences
Volume 32(LXVIII), 2022
No. 2, pages 359–381
Pitch and yaw motion control of 2 DoF helicopter
subjected to faults using sliding-mode control
M. RAGHAPPRIYA and S. KANTHALAKSHMI
This paper presents a fault-tolerant control scheme for a 2 DOF helicopter. The 2 DOF heli-
copter is a higher-order multi-input multi-output system featuring non-linearity, cross-coupling,
and unstable behaviour. The impact of sensor, actuator, and component faults on such highly
complex systems is enormous. This work employs sliding mode control, which is based on
reaching and super-twisting laws, to handle the problem of fault control. Simulation tests are
carried out to show the effectiveness of the algorithms. Various performance metrics are ana-
lyzed and the results show SMC based on super-twisting law provides better control with less
chattering. The stability of the closed-loop system is mathematically assured, in the presence of
faults, which is a key contribution of this research.
Key words: fault tolerant control, sliding mode control, reaching law, super-twisting, sensor,
actuator and component faults
1. Introduction
With the growing use of helicopters in civic and industrial applications such
as transportation, air-sea rescue, firefighting, military, and surveillance, key con-
cerns such as safety and reliability are becoming increasingly important. Heli-
copters are nonlinear by nature, with intrinsic unstability, cross-coupling effects,
unmodeled dynamics, and parametric uncertainties. Its versatility originates from
its unique maneuvering characteristics, which include the ability to fly long dis-
tances at low altitudes, take off and land quickly, fly at low speeds with excellent
stability, and hover throughout operations to meet specific needs. Furthermore,
the flight control issue is loaded with complexities. Flight stability can be dis-
Copyright © 2022. The Author(s). This is an open-access article distributed under the terms of the Creative Com-
mons Attribution-NonCommercial-NoDerivatives License (CC BY-NC-ND 4.0 https://creativecommons.org/licenses/
by-nc-nd/4.0/), which permits use, distribution, and reproduction in any medium, provided that the article is properly
cited, the use is non-commercial, and no modifications or adaptations are made
M. Raghappriya is with Department of Electronics and Instrumentation Engineering, Government
College of Technology, Coimbatore, India.
S. Kanthalakshmi is with Department of Electrical and Electronics Engineering, PSG College of
Technology, Coimbatore, India.
Received 8.10.2021. Revised 9.2.2022.
