Comparative Investigation of Feed-Forward Control Algorithms

T Tekorius,D Levisauskas

doi:10.5755/j01.eee.115.9.754

T Tekorius, D Levisauskas

Open Access

https://doi.org/10.5755/j01.eee.115.9.754

Copy DOI

Abstract

The paper presents investigation results of four different structures of feed-forward control algorithms applied for controlling processes, in which the time delay in the disturbance path is less than that in process path. The control algorithms were investigated via computer simulation of feed-back / feed-forward control system performance at various type disturbances and dynamical parameters of controlled process. The performance index for comparison of the transient responses in the control systems was the integral of absolute error. The investigation results show statistically significant improvement of the control system performance by using the dynamic (lead-lag) algorithm connected in series with PD control algorithm in a feed-forward controller as compared to the steady-state, the ordinary dynamic and the modified dynamic feed-forward control algorithms. Ill. 3, bibl. 6, tabl. 3 (in English; abstracts in English and Lithuanian). http://dx.doi.org/10.5755/j01.eee.115.9.754

Highlights

Feed-forward control is an effective way to reject the controlled process disturbances [1, 2]
The feed-forward control algorithm (8) in simulation experiments is realized as a lead-lag compensator in series with PD controller, transfer function of which coincides with the Padé approximation term (4)
Feed-forward controllers of different structures are investigated for controlling processes, in which the time delay in the disturbance path is less than that in process path

Summary

Introduction

Feed-forward control is an effective way to reject the controlled process disturbances [1, 2]. By applying the engineering design method, the feed-forward controller realization problem arises, when time delay in the disturbance path is less than time delay in process path. In this case, the negative dead-time term in feed-forward controller cannot be implemented, and it is advised to ignore this term [3, 4]. We investigate performance of the feed-forward controllers, in which the negative dead-time term is replaced with the Padé approximation. A simplified engineering method for the feed-forward controller design refers to first order plus time delay approximations of the controlled process dynamics with respect to control and disturbance actions: Gpr s.

Dynamic feed-forward in series with approximation

Conclusions