On Dα-type iterative learning control

The classical Arimoto D-type iterative learning control (ILC) updating law uses the first order derivative (with transfer function s) of tracking error. By using the fractional order derivative, it is proposed in this paper to use a fractional order ILC updating law where the fractional order derivative (with transfer function s(alpha), alpha is an element of (0, 1]) of tracking error is employed. The basic idea is explained in some detail together with a frequency domain design method. For implementation, a direct discretization technique is introduced. An example is given to show the benefits of the D-alpha-type ILC. Several remarks on future research topics are briefly discussed in the finally section.