Fault-Tolerant Control of a 2 DOF Helicopter
(TRMS System) Based on H∞
Abderrahmen BOUGUERRA
#1
, Djamel SAIGAA
#2
, Kamel KARA
*1
Samir ZEGHLACHE
#3
, Keltoum LOUKAL
#4
#1, 3, 4
LASS Laboratory, Department of Electrical engineering, University of M’sila,
#2
LASS Laboratory, Department of Electronics, University of M’sila,
BP 166 Ichbilia 28000 Algeria
1
rah_bou@yahoo.fr
2
saigaa_dj@yahoo.fr
3
zeghlache_samir@yahoo.fr
4
muohtlek@yahoo.fr
*
Department of Electronics, University of Blida,
Route De Soumaa BP 270 Blida Algeria
1
kara_k_dz@yahoo.fr
Abstract— In this paper, a Fault-Tolerant control of 2 DOF
Helicopter (TRMS System) Based on H∞ is presented. In
particular, the introductory part of the paper presents a Fault-
Tolerant Control (FTC), the first part of this paper presents a
description of the mathematical model of TRMS, and the last
part of the paper presented and a polytypic Unknown Input
Observer (UIO) is synthesized using equalities and LMIs. This
UIO is used to observe the faults and then compensate them, in
this part the shown how to design a fault-tolerant control
strategy for this particular class of non-linear systems.
Keywords
—
Helicopter model;
control; UIO; state feedback
control; MM; FTC.
I. I
NTRODUCTION
Fault-Tolerant Control (FTC) is a relatively new idea that
makes possible to develop a control feedback that allows
keeping the required system performance in the case of faults
[1]. The control strategy can be perceived fault tolerant when
there is an adaptation mechanism that changes the control law
in the case of faults. Another solution is to use hardware
redundancy in sensors and/or actuators. In general, FTC
systems are classified into two distinct classes [2]: passive and
active. In passive FTC [3] [4], controllers are designed to be
robust against a set of presumed faults, therefore there is no
need for fault detection. In the contrast to passive ones, active
FTC schemes, react to system components faults actively by
reconfiguring control actions, and by doing so the system
stability and acceptable performance is maintained.
Due to the complicated nonlinearity and the high coupling
effect between two propellers, the control problem of the
(TRMS) has been considered as a challenging research topic
[5]. Moreover, the control of the TRMS has gained a lot of
attention because the dynamics of the TRMS and a helicopter
are similar in certain aspects [6], [7]. A multivariable
nonlinear H∞ controller is designed in [8] for the angle
control of the TRMS. The remainder of this paper is organized
as follows. The model of the TRMS is described in Section II.
The FTC strategy is designed in Section III. Section IV
presents the simulation results to demonstrate the
effectiveness of the FTC Controller. Concluding remarks are
provided in Section VI.
II. M
ODEL
D
ESCRIPTION OF THE
TRMS
Similar to most flight vehicles, the helicopter consists of
several elastic parts such as rotor, engine and control surfaces.
The nonlinear aerodynamic forces and gravity act on the
vehicle, and flexible structures increase complexity and make
a realistic analysis difficult. For control purpose, it is
necessary to find a representative model that shows the same
dynamic characteristics as the real aircraft [9]. The behaviour
of a nonlinear TRMS, (shown in Fig.1), in certain aspects
resembles that of a helicopter. It can be well perceived as a
static test rig for an air vehicle with formidable control
challenges.
Fig.1 The twin rotor multi-input multi-output system (TRMS) [10]
Vertical rotation trajectory
Horizontal rotation trajectory
Tail DC-motor
Beam
α
On
Off
α
