source: mso/eml/controllers/pids.mso @ 1

Last change on this file since 1 was 1, checked in by Rafael de Pelegrini Soares, 17 years ago

Initial import of the library
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  • Property svn:keywords set to Id
File size: 6.2 KB
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1#*-------------------------------------------------------------------
2* Model of PIDs
3*--------------------------------------------------------------------
4*  - Inputs
5*       - a scaled processs variable
6*       - a scaled bias
7*       - a scaled setpoint
8*
9*  - Outputs
10*   - a scaled output
11*
12*  - Assumptions
13*
14*
15*--------------------------------------------------------------------
16* Author: Tiago Osório
17* $Id: pids.mso 1 2006-06-20 17:33:53Z rafael $
18*-------------------------------------------------------------------*#
19using "types";
20
21Model PID_basic
22
23        PARAMETERS
24        bias       as positive (Brief="Previous scaled bias", Lower=0, Upper=1, Default=0.5);
25        alpha      as positive (Brief="Derivative term filter constant", Default=1);
26        beta       as positive (Brief="Proportional term setPoint change filter");
27        gamma      as positive (Brief="Derivative term SP change filter");
28        action     as Real     (Brief="Controller action: (-1) Direct,(1) Reverse", Default=-1);
29       
30        VARIABLES
31        gain       as positive           (Brief="Controller gain", Lower=0, Upper=1, Default=0.5);
32        derivTime  as Real               (Brief="Derivative time constant", Unit="s");
33        intTime    as Real               (Brief="Integral time constant", Unit="s");
34    autoMan    as Real                   (Brief="Controller option: (0) Automatic, (1) Manual");   
35        input      as control_signal (Brief="Previous scaled input signal", Default=0.5);
36        setPoint   as Real               (Brief="Scaled setPoint", Lower=0, Upper=1, Default=0.5);
37        dFilt      as Real               (Brief="Derivative term filter constant", Default=0.5);
38        derivTerm  as Real               (Brief="Derivative term", Default=0);
39        propTerm   as Real               (Brief="Proportional term", Default=0);
40        intTerm    as Real               (Brief="Integral term", Default=0);
41        output     as control_signal (Brief="Scaled output signal", Default=0);
42        outp       as control_signal (Brief="Sum of proportional, integral and derivative terms");
43        error      as Real               (Brief="Error definition for proportional term");
44        errorD     as Real           (Brief="Error definition for derivative term");
45        outps      as Real           (Brief="Variable outp scaled between -1 and 1");
46        clip       as Real           (Brief="Controller option: (1) output clipped, (0) output unclipped");
47       
48        EQUATIONS
49
50       
51        if autoMan equal 0 then
52                "Error definition"     
53                error = beta*setPoint - input;
54                errorD= gamma*setPoint - input;
55        else
56                "Error definition"
57                error = input*(beta-1.0);
58                errorD= input*(gamma-1.0);
59        end
60       
61        "Calculate proportional term"
62        propTerm=error;
63       
64        if (derivTime equal 0) then
65                "Derivative term filter"       
66                alpha*(derivTime + 1*"s")*diff(dFilt) = errorD - dFilt;
67        else
68                "Derivative term filter"                       
69                alpha*(derivTime)*diff(dFilt) = errorD - dFilt;
70        end
71
72        "Calculate derivative term"
73        derivTerm = derivTime*diff(dFilt);
74       
75        "Scale outp"
76        outps=2*outp-1;
77       
78        if clip equal 1 then
79                if abs(outps)>1 then
80                        "Calculate output"
81                        output=(sign(outps)*1+1)/2;
82                else
83                        "Calculate output"
84                        output=outp;
85                end
86        else
87                "Calculate output"
88                output=outp;
89        end
90               
91        INITIAL
92        intTerm = 0;
93        diff(dFilt) = 0*"1/s";
94       
95end
96
97
98Model PID_Ideal_AW as PID_basic
99       
100        VARIABLES
101        AWFactor     as Real     (Brief="Integral term multiplier used in anti-reset windup");
102
103        EQUATIONS
104       
105        "Calculate integral term with anti-windup"
106        intTime*diff(intTerm) = AWFactor*(setPoint - input);
107       
108        "Sum of proportional, integral and derivative terms"
109        outp = bias + action*gain*(propTerm + intTerm + derivTerm);
110
111        if abs(outps)>1 and (action*sign(outps)*(setPoint-input))>0 then
112                "Calculate AWFactor"
113                AWFactor=-tanh(sign(outps)*outps*100-102);
114        else
115                "Calculate AWFactor"
116                AWFactor=1;
117        end
118end
119
120Model PID_Parallel_AW as PID_basic
121       
122        VARIABLES
123        AWFactor     as Real     (Brief="Integral term multiplier used in anti-reset windup");
124
125        EQUATIONS
126       
127        "Calculate integral term with anti-windup"
128        intTime*diff(intTerm) = AWFactor*(setPoint - input);
129       
130        "Sum of proportional, integral and derivative terms"
131        outp = bias + action*(gain*propTerm + intTerm + derivTerm);
132
133        if abs(outps)>1 and (action*sign(outps)*(setPoint-input))>0 then
134                "Calculate AWFactor"
135                AWFactor=-tanh(sign(outps)*outps*100-102);
136        else
137                "Calculate AWFactor"
138                AWFactor=1;
139        end
140end
141
142Model PID_Series_AW as PID_basic
143       
144        VARIABLES
145        AWFactor     as Real     (Brief="Integral term multiplier used in anti-reset windup");
146       
147        EQUATIONS
148       
149        "Calculate integral term with anti-windup"
150        intTime*diff(intTerm) = AWFactor*(setPoint - input);
151
152        "Sum of proportional, integral and derivative terms"
153        outp = bias + action*(gain*(propTerm + intTerm)*(1 + derivTerm));
154
155        if abs(outps)>1 and (action*sign(outps)*(setPoint-input))>0 then
156                "Calculate AWFactor"
157                AWFactor=-tanh(sign(outps)*outps*100-102);
158        else
159                "Calculate AWFactor"           
160                AWFactor=1;
161        end
162end
163
164Model PID_Ideal as PID_basic
165       
166        EQUATIONS
167       
168        "Calculate integral term"
169        intTime*diff(intTerm) = setPoint - input;
170       
171        "Sum of proportional, integral and derivative terms"
172        outp = bias + action*gain*(propTerm + intTerm + derivTerm);
173
174end
175
176Model PID_Parallel as PID_basic
177       
178        EQUATIONS
179       
180        "Calculate integral term"
181        intTime*diff(intTerm) = setPoint - input;
182       
183        "Sum of proportional, integral and derivative terms"
184        outp = bias + action*(gain*propTerm + intTerm + derivTerm);
185
186end
187
188Model PID_Series as PID_basic
189       
190        EQUATIONS
191
192        "Calculate integral term with anti-windup"
193        intTime*diff(intTerm) = setPoint - input;
194       
195        "Sum of proportional, integral and derivative terms"
196        outp = bias + action*(gain*(propTerm + intTerm)*(1 + derivTerm));
197
198end
199
200Model PID_Ideal_AWBT as PID_basic
201       
202        EQUATIONS
203       
204        "Calculate integral term with anti-windup and bumpless transfer"
205        action*gain*(intTime*diff(intTerm)-(setPoint-input)) = output-outp;     
206       
207        "Sum of proportional, integral and derivative terms"
208        outp = bias + action*gain*(propTerm + intTerm + derivTerm);
209
210end
211
212Model PID_Parallel_AWBT as PID_basic
213       
214        EQUATIONS
215       
216        "Calculate integral term with anti-windup and bumpless transfer"
217        action*gain*(intTime*diff(intTerm)-(setPoint-input)) = output-outp;     
218       
219        "Sum of proportional, integral and derivative terms"
220        outp = bias + action*(gain*propTerm + intTerm + derivTerm);
221
222end
223
224Model PID_Series_AWBT as PID_basic
225       
226        EQUATIONS
227       
228        "Calculate integral term with anti-windup and bumpless transfer"
229        action*gain*(intTime*diff(intTerm)-(setPoint-input)) = output-outp;     
230
231        "Sum of proportional, integral and derivative terms"
232        outp = bias + action*(gain*(propTerm + intTerm)*(1 + derivTerm));
233
234end
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