Graham

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11 years, 16 days

MaplePrimes Activity


These are replies submitted by Graham

Hi Simon,

 

 Just to elaborate a bit and get a better idea of your thought process, I thought I'd add some info here:

 

I think there may be some confusion here concerning the RB’s inertia matrix.  The inertia matrix associated with the rigid body defines it’s resistance to rotational acceleration about its CoM axes.  Assuming that the mass is at the end of a rope (i.e. it’s a rope and not a solid link who’s orientation is forced to be the same as the mass’s orientation), then this doesn’t change regardless of the length of the rope.  The rotational inertia of the rope + mass (about the axis at the tip of the crane) is affected by the length of the rope, but this is automatically accounted for in the dynamic equations (the user doesn’t have to do anything to account for it).

 

Hopefully this information helps you out.

Hi Simon,

 

 Just to elaborate a bit and get a better idea of your thought process, I thought I'd add some info here:

 

I think there may be some confusion here concerning the RB’s inertia matrix.  The inertia matrix associated with the rigid body defines it’s resistance to rotational acceleration about its CoM axes.  Assuming that the mass is at the end of a rope (i.e. it’s a rope and not a solid link who’s orientation is forced to be the same as the mass’s orientation), then this doesn’t change regardless of the length of the rope.  The rotational inertia of the rope + mass (about the axis at the tip of the crane) is affected by the length of the rope, but this is automatically accounted for in the dynamic equations (the user doesn’t have to do anything to account for it).

 

Hopefully this information helps you out.

Hi Mozzam,

 

 I realize it has been a few weeks since this post. Have you figured out a solution yet? If not, I will be glad to help you. Thanks.

 

-Graham

You're welcome - I'm glad to hear everything worked out.

You're welcome - I'm glad to hear everything worked out.

@Onnimikki 

 

Sorry about that! Here's the text:

 

But you can for example get all equations with functions called foo* (the suffixed part of the structured type does that match) with say:

select(hastype, [foobar(t)+1=11,barfot(t)-1=14], typefunc(anything,suffixed(`foo`,anything)));

@Onnimikki 

 

Sorry about that! Here's the text:

 

But you can for example get all equations with functions called foo* (the suffixed part of the structured type does that match) with say:

select(hastype, [foobar(t)+1=11,barfot(t)-1=14], typefunc(anything,suffixed(`foo`,anything)));

Hi James,

 

 Unfortunately, I'm not an expert at using the 'filter' option. A colleague of mine has this piece of advice, but it may not be directly applicable to your needs:

 



 

I hope that helps in some way. Good luck!

 

-Graham

Hi James,

 

 Unfortunately, I'm not an expert at using the 'filter' option. A colleague of mine has this piece of advice, but it may not be directly applicable to your needs:

 



 

I hope that helps in some way. Good luck!

 

-Graham

@Onnimikki 

 

Hi James,

 

 You can use GetEquations to toggle symbolic representation in outputs, too. You just need to include the 'params' option in the GetEquations command.

params : one of the following: set, list or "all"
Specifies which parameters to leave symbolic in the returned equations.  By default, only parameters explicitly defined on the active subsystem are left symbolic.

I opened your model, and modified the GetEquations command to include   'params' = all , and I was able to see your resistor parameters.

Give it a shot and let me know if you need anything else.

 

-Graham

@Onnimikki 

 

Hi James,

 

 You can use GetEquations to toggle symbolic representation in outputs, too. You just need to include the 'params' option in the GetEquations command.

params : one of the following: set, list or "all"
Specifies which parameters to leave symbolic in the returned equations.  By default, only parameters explicitly defined on the active subsystem are left symbolic.

I opened your model, and modified the GetEquations command to include   'params' = all , and I was able to see your resistor parameters.

Give it a shot and let me know if you need anything else.

 

-Graham

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