Digital 2-dof PID controller with Time Division Output (TDO)
Description
Proportional + Integral + Derivative with two degree of freedom
controller with Automatic, Tracking, Manual mode and bias signal.
The controller is implemented in its incremental form
algorithm.
The control law is defined as
[ 1 sTd ]
CS(s) = Kp[ (bSP(s) - PV(s)) + ----- (SP(s) - PV(S)) + -----------(cSP(s) - PV(s)) ]
[ sTi 1 + sTd/N ]
| Name |
Description |
Conditional? |
| SP |
Set Point |
NO |
| PV |
Process Variable |
NO |
| CS |
Control Signal |
NO |
| satHI |
CS at HIGH saturation |
NO |
| satLOW |
CS at LOW saturation |
NO |
| TR |
Track Reference signal |
YES (useTS) |
| TS |
Track Switch signal |
YES (useTS) |
| Bias |
Biasing signal |
YES (useBIAS) |
| MAN |
Manual Switch signal |
YES (useMAN) |
| CSinc |
Control Signal increment |
YES (useMAN) |
| Finc |
Forbid increment |
YES (useForbid) |
| Fdec |
Forbid decrement |
YES (useForbid) |
And some of them can be conditionally selected, by specifying a
boolean flag.
Time Division Output (TDO)
The Control Signal CS computed by the
PID controller can have two values: CSmin and CSmax.
The result is a rectangular wave, which duty cycle is proportional
to the control action computed by the controller.
The sampling time Ts is divided in
TDsteps intervals. For each one of
these sub intervals,
the CS may be at CSmin or CSmax. This results in a very high frequency
sampling that may slow down the simulation.
AntiWindUp mode
If the boolean flag AntiWindup is tue
the output of the block ( CS )
saturates at the values specified by CSmin and CSmax.
Tracking mode
If the boolean flag useTS is true, the
inputs TS and TR are enabled.
When enabled, if the TS signal is true
the output CS is forced to follow the
track reference signal TR.
Manual mode
If the boolean flag useMAN is true, the
inputs MAN and CSinc are enabled.
When enabled, if the MAN signal is true
the output CS can be manually
controlled via the signals CSinc and
CSdec, that respectively increment or
decrement the control signal.
Forbid mode
If the boolean flag useForbid is true,
the inputs Finc and Fdec are enabled.
When enabled, if the Finc signal is
true the output CS cannot grow up,
while if Fdec is true it cannot
decrease.
Discretisation
The controller is implemented directly through an algorithm, that
represents the discretised version of the continuous time
controller.
- Industrial Control Systems (v 1.0.0) : April-May 2012
-
- List of revisions:
-
- 11 May 2012 (author: Marco Bonvini)
- Main Authors:
- Marco Bonvini; <bonvini@elet.polimi.it>
- Alberto Leva <leva@elet.polimi.it>
- Politecnico di Milano
- Dipartimento di Elettronica e Informazione
- Via Ponzio 34/5
- 20133 Milano - ITALIA -
- Copyright:
- Copyright © 2010-2012, Marco Bonvini and Alberto
Leva.
- The IndustrialControlSystems package is free
software; it can be redistributed and/or modified under the terms
of the Modelica license.
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