Article
Trajectory Tracking of a Tri-Rotor Aerial Vehicle
Using an MRAC-Based Robust Hybrid
Control Algorithm
Zain Anwar Ali *, Daobo Wang, Muhammad Aamir and Suhaib Masroor
College of Automation Engineering, Nanjing University of Aeronautics and Astronautics, Nanjing 210016,
China; dbwangpe@nuaa.edu.cn (D.W.); muaamir5@yahoo.com (M.A.); suhaibmasroor1@gmail.com (S.M.)
* Correspondence: zainanwar86@hotmail.com; Tel.: +86-130-1693-1051
Academic Editor: Michael Wing
Received: 2 November 2016; Accepted: 20 December 2016; Published: 19 January 2017
Abstract:
In this paper, a novel Model Reference Adaptive Control (MRAC)-based hybrid control
algorithm is presented for the trajectory tracking of a tri-rotor Unmanned Aerial Vehicle (UAV).
The mathematical model of the tri-rotor is based on the Newton–Euler formula, whereas the
MRAC-based hybrid controller consists of Fuzzy Proportional Integral Derivative (F-PID) and Fuzzy
Proportional Derivative (F-PD) controllers. MRAC is used as the main controller for the dynamics,
while the parameters of the adaptive controller are fine-tuned by the F-PD controller for the altitude
control subsystem and the F-PID controller for the attitude control subsystem of the UAV. The stability
of the system is ensured and proven by Lyapunov stability analysis. The proposed control algorithm
is tested and verified using computer simulations for the trajectory tracking of the desired path
as an input. The effectiveness of our proposed algorithm is compared with F-PID and the Fuzzy
Logic Controller (FLC). Our proposed controller exhibits much less steady state error, quick error
convergence in the presence of disturbance or noise, and model uncertainties.
Keywords:
Model Reference Adaptive Control; Fuzzy Logic Controller (FLC); trajectory tracking;
tri-rotor UAV
1. Introduction
Currently, research in the area of control engineering is focused on the field of unmanned flight
body aircraft, such as helicopters, hex-rotor, quad-rotor, and tri-rotor robots, due to their variety of
applications, especially in the area of defense [
1
–
4
]. Other areas include surveillance, environmental
monitoring, agriculture, and media coverage. For any unmanned flight, the position and altitude of
the robot can take advantage of sensor information [
5
,
6
]. This paper provides a trajectory tracking
control algorithm for the tri-rotor aerial vehicle by taking advantage of vertical takeoff and landing
(VTOL). The unmanned tri-rotor system is used for imaging of forest fires, accidents, surveillance,
transportation, and the detection of manholes [
7
–
11
]. The full weight of the system depends on
controlling the external bars, which requires high energy consumption.
The tri-rotor aerial vehicle has four input commands, Col, Lat, Lon, and Ped, for altitude, latitude,
longitude, and angular control command. The nine outputs are (p, q, r), (u, v, w), and (
ϕ
,
θ
,
ψ
), which
are the rotational velocity, translational velocity, and Euler angles [
12
]. To rectify the rotor reaction that
is found in yaw moments, a Brushless Direct Current (BLDC) motor is fixed to the triangular structure
of the tri-rotor.
Some of the main reasons that the tri-rotor UAV is superior to the quad-rotor aerial vehicle are as
follows: (i) Orientation of Unmanned Aerial Vehicle (UAV): By comparing the tri-rotor UAV with the
quad-rotor UAV structure, the orientation of the quad-rotor rapidly disappears at larger distances due
Aerospace 2017, 4, 3; doi:10.3390/aerospace4010003 www.mdpi.com/journal/aerospace
