Adaptive Compensation and Control for Uncertain Systems with
Prandtl-Ishlinskii Hysteresis
Jinwen Zheng, Qinglin Wang, Yuan Li
School of Automation, Beijing Institute of Technology, Beijing, 100081
E-mail: zhijinwen@yeah.net, wangql@bit.edu.cn, liyuan@bit.edu.cn
Abstract: The hysteresis for a class of smart-material-based actuators is represented by adopting Prandtl-Ishlinskii
model and a controller was designed based on the indirect adaptive robust control framework. In order to reduce the
hysteresis effect, least squares method for on-line parameter estimation and the associated approximate model for inverse
compensation are employed. And the inversion error is analyzed quantitatively. A robust controller is then designed to
accommodate uncertain and nonlinearities and make the system stable. The simulation shows that the adaptive robust
controller has not only good output tracking performance but also accurate parameter estimates.
Key Words: Adaptive control, identification, Prandtl-Ishlinskii model, hysteresis.
1 INTRODUCTION
In recent years, the smart material such as electro-active
polymer (EAP), shape memory alloy (SMA), has got great
development. Many actuators based on smart-material e-
merged [1-3]. However, hysteresis effect exists widely
in the smart-material-based actuator (SMBA) system. It
would lead to poor tracking accuracy or even instability and
self-sustaining oscillation. So the essential control prob-
lem for SMBA is how to deal with the hysteresis nonlin-
earity. The common hysteresis models are Preisach model,
Prandtl-Ishlinskii (P-I) model and Bouc-Wen model. The
general method that deals with the hysteresis method is to
use the inverse hysteresis model for compensation to atten-
uate hysteresis effect. Unfortunately, it is difficult to cal-
culate the inverse model of Preisach model. The existing
adaptive techniques generally require a linear parameteri-
zation of the plant dynamics[4]. Bouc-Wen model does not
have this property, though the inverse model of Bouc-Wen
model can be got analytically [5]. The P-I model has not
only analytical inverse model but also the property of lin-
ear parameterization. So P-I model is widely applied to
represent hysteresis of SMBA.
Reference[6]adopts back-stepping adaptive control
scheme, and references[7-9]use adaptive sliding model
control scheme. These methods belong to direct adaptive
robust control. The advantage of these methods is that it
can make the plants achieve good output tracking perfor-
mance. But it has a poor ability on parameter estimation.
Reference [10]applies off-line parameter estimation and
adopts sliding model control to attenuate the inversion
error. The shortcoming of this control strategy is that the
work of off-line identification is tedious and the designer
should design the controller again when the size of actu-
ator changed. Reference[11, 12]research the method of
This work is supported by National Nature Science Foundation under
Grant 61375100 and 61472037.
parameter estimation of hysteresis system, but the control
schemes is not given.
In this paper, we apply the indirect adaptive robust con-
trol (IARC) scheme. This control scheme is widely used in
hydraulic manipulators[13, 14]. In IARC framework, the
design of parameter estimator and the design of controller
are relatively independent. The parameter estimator is al-
ways designed based on least squares method or gradient
method. And a robust controller is used to attenuate the
uncertain of system. The advantage of this method is that
it can enable the plants achieve not only excellent track-
ing performance but also accurate parameter estimates for
secondary application such as fault diagnosis[14]. In this
paper, we use least squares estimator and sliding mode con-
troller.
2 PRANDTL-ISHLINSKII MODEL
Because P-I model[15] is defined based on play operator,
the play operator is introduced firstly. Let C
m
[0,t
E
] denotes
the space of piecewise monotone continuous function on
[0,t
E
]. For all u(t) ∈ C
m
[0,t
E
], there exists a partition of
[0,t
E
] denoted by 0 = t
0
< t
1
< t
2
< ... < t
N
= t
E
such that
u(t) is monotone on each subinterval [t
i
,t
i+1
]. Then, the
play operator is defined as follows:
⎧
⎨
⎩
P
r
[u,
π
0
](0)= f
r
(u(0),
π
0
),
P
r
[u,
π
0
](t)= f
r
(u(t), P
r
[u,
π
0
](t
i
));
t
i
< t ≤t
i+1
, 0 ≤ i < N
f
r
(u, w)=max(u −r, min(u + r, w)).
(1)
where r > 0 is threshold,
π
0
is the initial value, u(t) is the
input of the operator and P
r
[u,
π
0
](t) is the output of the
operator. The simulation experiment shows that the initial
value does not affect the shape of the hysteresis loop. And
if the actuator starts from its de-energized state, the initial
condition can be set to zero [16]. So we assume
π
0
= 0 and
let P
r
[u](t) := P
r
[u, 0](t) .
1344
978-1-4799-7016-2/15/$31.00
c
2015 IEEE