 
Summary: Discussion on "A Gradientbased Repetitive Control
Algorithm Combining ILC and Pole Placement"
Konstantin Avrachenkov
INRIA Sophia Antipolis
2004, Route des Lucioles, 06902, France
Email: K.Avrachenkov@sophia.inria.fr
Iterative Learning Control (ILC) and Repetitive Control
(RC) are relatively new research methodologies for improving
the performance of systems that operate in a cyclic mode.
The general form of Iterative Learning Control can be given
as follows:
uk(t) = L{ei(), ui(), [0, T], i = 1, ..., k  1},
t [0, T], k = 1, 2, ... , (1)
where L is a learning operator that generates a command
for the next cycle based on the information about the errors
and commands from previous cycles. The error is defined by
ek(t) = r(t)yk(t), where r(t), t [0, t], is the desired output
which the system must track repetitively. The time parameter
t can be either continuous or discrete. The general form of
Repetitive Control can be given as follows:
