How can I edit SimMechanics block parameters programmatically?

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Matthew Eicholtz
Matthew Eicholtz 2012-6-29
评论： Szymon Maczka 2019-5-8
I am writing a script to generate a SimMechanics model programmatically and need some help.
bdclose('all') % close all Simulink models
new_system('K') % start a new model called K
open_system('K') % open the new model called K
load_system('mylib') % loads my custom library of SimMechanics blocks (these are just the basic blocks: body, ground, revolute, prismatic, etc.)
For a block like ground, I can add it to the model and change parameters as follows:
add_block('mylib/Ground','K/Ground',...
'CoordPosition','[# # #]',...
'ShowEnvPort','on'); % where [# # #] is an arbitrary location
I can also add the machine environment block and modify it:
add_block('mylib/Machine Environment','K/Machine Environment',...
'Gravity','[0 0 0]');%,...
'Dimensionality','2D Only',...
'AnalysisType','Kinematics',...
'VisualizeMachine','off')
Here is the problem: I cannot seem to properly modify some the Body block parameters
add_block('mylib/Body','K/Body',...
'Mass','0',...
'Inertia','zeros(3)',...
'CGPos','[# # #]',...
'CS1Pos','[# # #]',...
'CS2Pos','[# # #]');
Obviously, replace the '#' with actual numbers. When I run the code, the CS positions are not altered when I double-click on the block in the model. I found that I can change the CG line as follows:
CGstr = ['Left$CG$[# # #]'$WORLD$WORLD$m$[0 0 0]$Euler X-Y-Z$deg$WORLD$false$none'];
and replace...
'CGPos','[# # #]'
in the previous 'add_block' code with
'CG',CGstr
and it works. But I can't do it for the CS1, CS2, etc...Any suggestions?
  2 个评论
Kaustubha Govind
Kaustubha Govind 2012-6-29
What about if you use SET_PARAM after calling add_block('mylib/Body','K/Body')?
Matthew Eicholtz
Matthew Eicholtz 2012-6-29
I tried using SET_PARAM as you suggest, but it seemed to produce strange results.
When I selected View->Block Data Tip Options->Parameter Names and Values and hovered over the object, it looked like the changes took effect, but it didn't show up when I double-clicked on the block itself.

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采纳的回答

Ryan G
Ryan G 2012-6-29
It looks like you found that string in the model file. There is a similar string for 'WorkingFrames'
'Left$CS1$[0 0 0]$CG$CG$m$[0 0 0]$Euler X-Y-Z$deg$WORLD$true$none#Right$CS2$[0 0 0]$CG$CG$m$[0 0 0]$Euler X-Y-Z$deg$WORLD$true$none'
So I can set
x = 'Left$CS1$[0 0 0]$CG$CG$m$[0 0 0]$Euler X-Y-Z$deg$WORLD$true$none#Right$CS2$[0 0 0]$CG$CG$m$[0 0 0]$Euler X-Y-Z$deg$WORLD$true$none';
and do this
add_block('mblibv1/Bodies/Body','K/Body',... 'Mass','0',... 'Inertia','zeros(3)',... 'CGPos','[0 0 0]',... 'WorkingFrames',x);
but you need to set all your frames in that one big string.

更多回答（2 个）

Falk
Falk 2013-1-30
There is a another way to change CS-values within a body-block via code.
First, you have to build a subsystem around the body-block. You have to build a mask for the subsystem. In the mask you can define parameters. These parameters you can use as variables in the CS- or CG-positions within the body-block-mask.
At this point, everything was stupidyclicki...
But the mask-parameters you can set via code, e.g.
set_param('myModel/SubsystemName','maskparameter',num2str(value))
Each occurence of 'maskparameter' within the underlying body-block will copy its value from the subsystem (one level above) to the variable in the body-block.
Parham Sagharichi ha
i wanna change number of ports for joint revloute , what should i do ?
  1 个评论
Szymon Maczka
Szymon Maczka 2019-5-8
Good question... I am trying to do the same with 'Spring and Damper Force' for changing stiffness parameter during simulation #2018b

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