Iterative Learning Control of Integer and Noninteger Order: an Overview
Mihailo Lazarević
This paper provides an overview of the recently
presented and published results relating to the use of
iterative learning control (ILC) based on and integer
and fractional order. ILC is one of the recent topics in
control theories and it is a powerful control concept
that iteratively improves the behavior of processes that
are repetitive in nature. ILC
is suitable for
controlling
a wider class of mechatronic systems - it
is
especially suitable for motion control of robotic
systems that attract and hold an important position in
biomechatronical,
technical systems involving the application,
military industry,
etc.
The first part of the paper presents the results
relating to the application of higher integer order PD
type ILC with numerical simulation. Also, another
integer order ILC scheme is proposed for a given robotic
system with three degrees of freedom for task-space
trajectory tracking where the effectiveness of the
suggested control is demonstrated through a simulation
procedure. In the second part, the results related to
the application of the fractional order of ILC are
presented where
type
of ILC is proposed
firstly,
for a
fractional order linear time invariant system. It is
shown that under some sufficient conditions which
include the learning operators, convergence of the
learning system can be guaranteed. Also,
type
of ILC is suggested for a fractional order linear time
delay system. Finally, sufficient conditions for the
convergence in the time domain of the proposed ILC were
given by the corresponding theorem together with its
proof.