This example shows the simulation of a parallel compensated servo system using

QFIRE Studio

.

Introduction

Parallel compensation in servo systems is usually implemented with a velocity feedback sensor and a proportional controller. Here, we use the

QFIRE CTR-101

as a digital controller and the plant model below (see [1]):

In Figure 1, the inner loop is compensated by the

QFIRE

while the outer loop tracks the reference position signal.

Simulation

The controller gain was determined as 

. This is an approximation to , it is automatically computed by

QFIRE Studio

as the best fixed-point approximation supported by

QFIRE CTR-101

. It sets the damping ratio of the dominant closed-loop poles to 0.4.

A 1V offset scaling is required to fit the computed control signal in the expected range. Figure 2 shows all blocks used in the control task.

Consequently, the scale correction outside the controller is performed by an amplifier circuit.

The step response of the position control system is shown in Figure 3.

Bibliographic References

[1] - Katsuhiko Ogata,

Modern Control Engineering

, Fourth Edition, Delhi: Pearson, 2003.