Problem in OCST

[ผศ.ดร.ศุภชัย วรพจน์พิศุทธิ์]

Hello,

I plan to use Octave in my control theory classroom. However, I found some
strange problems while trying to simulate DC motor with PI controller.
Function bode() does not work even it should be. Now, I am using Octave
2.1.50a on Win2k downloaded from octave.sf.net. May someone please explain
how to solve this problem?

Thank you in advance
Supachai

>> motor = tf2sys([4500],[1 361.2 0]);
>> PI = tf2sys([1 0.1],[1 0]);
>> G = sysmult(motor,PI);
warning: in
/opt/octave/share/octave/2.1.50/m/control/system/__sysgroupn__.m near line
44, column 9:

>>> warning ("sysgroup: %s name(%d) = %s name(%d) = %s", kind, ii, kind,
jj, st1);


warning: sysgroup: state name(1) = state name(3) = x_1
warning: sysgroup:     changed state name 3 to x_1_3
>> bode(G)
error: number of columns must match (2 != 1)
error: evaluating assignment expression near line 97, column 7
error: evaluating if command near line 71, column 3
error: called from `sysgroup' in file
`/opt/octave/share/octave/2.1.50/m/control/system/sysgroup.m'
error: evaluating assignment expression near line 96, column 9
error: evaluating if command near line 65, column 3
error: called from `sysmult' in file
`/opt/octave/share/octave/2.1.50/m/control/system/sysmult.m'
error: evaluating assignment expression near line 146, column 11
error: evaluating while command near line 95, column 3
error: called from `zp2ss' in file
`/opt/octave/share/octave/2.1.50/m/control/system/zp2ss.m'
error: evaluating if command near line 109, column 5
error: evaluating if command near line 107, column 3
error: called from `sysupdate' in file
`/opt/octave/share/octave/2.1.50/m/control/system/sysupdate.m'
error: evaluating assignment expression near line 153, column 9
error: evaluating if command near line 152, column 3
error: called from `sysgetsignals' in file
`/opt/octave/share/octave/2.1.50/m/control/system/sysgetsignals.m'
error: called from `bode' in file
`/opt/octave/share/octave/2.1.50/m/control/base/bode.m'
>>



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