Non-optimal block pulse function (NOBPF)‎ based analysis and identification of SISO control systems

Abstract EN

Conventional block pulse functions have been around for about twenty five years.

This orthogonal function set is the most fundamental and suitable for application in many areas including control theory.

In this paper, a ‘non-optimal’ method of block pulse function coefficient computation has been suggested which employs trapezoidal integration instead of exact integration.

This apparently ‘non-optimal’ procedure has been adopted in this work for control system analysis and identification, mainly because the trapezoidal integration uses only samples of the function to be expanded via BPF and thus reduces computational burden drastically.

The results of such analysis, when compared to the results obtained via traditional BPF approach, are found to contain less error and also, results of identification are found to be much more superior to conventional BPF based analysis.

It is also found that the results of identification via BPF are highly erroneous and contain undesired oscillations in many cases.

Three plants of two different orders have been studied with two standard inputs each to provide strong support for the proposition.

Lastly, an error estimate has been made for function approximation via this new approach and the results are compared with estimated error via conventional BPF analysis.

The non-optimal BPF approach proves to be better in many cases compared to the traditional BPF approach.