uomcsg

40 Reputation

6 Badges

4 years, 340 days

MaplePrimes Activity


These are replies submitted by uomcsg

Hello,

I ended up solving this manually. But can you try the following:

and replace the ?? with the equation. Let me know if this does the job.

@tomleslie 

Please check the edit I made.

@OrangVahid 

With all respect, I don't know what made you think I need " to learn more about modeling with MapleSim " but you can refer to my YouTube channel for reference.

Due to the geometric nature of a triangular delta robot, all of those additional revolute joints are needed to align the axis of rotation of a joint with the reference frame. And the links are perfectly fine to be massless as long as there is a rigid body attached to the end effector. 


I have managed to resolve this issue by updating Maple18 to the latest available version Maple18.02.

 

@John May I have uploaded the document.

@Thomas Richard 

It turns out that unless the Excel file is deleted and reattached, the changes that are made inside the file do not get synchronised with MapleSim.

@ThU 

That was very helpful, thank you!

@Joe Riel 

It's a pulse train. I have got different trapezoid signals for each leg. (The robot has six legs, it's a hexapod)

The visual below shows the details of one of the signals:

The issue with the triggered trapezoid signal is the boolean signal that is fed into it needs to tell the trapezoid when to make a transition (both for HIGH to LOW and LOW to HIGH). However, in my case, I can only tell it when to initiate the signal. I'm still working on it, I will update you on this shortly.

@Joe Riel 

Okay this time I will try to make it more clear by providing some visuals.

First of all, I have a model that follows the given pathway by 2 navigation controllers. (I prefered to use PID controllers)

Which works fine for the curves less than 45 degrees where the error signal fluctates between 0.7 and -0.7.

However, if the curve exceeds 45 degrees the error is larger than the badwidth of 0.7 and -0.7 thus a boolean (logic) signal of HIGH is generated.

When a LOW to HIGH transition is detected, the trapezoid signals (which triggers a "turn around algorithm") should be initiated. I need the trapezoid signal to start exactly when the error signal exceeds the badwidth of 0.7 and -0.7.

The only thing I could think of was to add the time taken for the model to exceed the error badwidth of 0.7 and -0.7 (which generates a LOW to HIGH transition) to the trapezoid signal as a time offset.

The visual below shows the flow chart.

If the time offset is not added to the trapezoid signal; besides there would be quantisation error, the Turn Around (TA) algorithm will not be deactivate by counting the rising edges in the signal.

(Note: 2nd rising edge corresponds to roughly 30 degrees of rotation of the model)

I hope that explains it

@Joe Riel 

Hello, @Joe Riel 

I need my trapezoid signal to initiate when a certain event occurs which is as follows,

I have a model that navigates using PID controller, the error is between 0.7 and -0.7 for curves less than 45 degrees.

If the curve exceeds 45 degrees, the trapezoid signal should take over and redirect the model back to the desired position.

Therefore I need to add the amount taken for the model to exceed the error badwidth of 0.7 and -0.7 to the trapezoid signal as a time offset.

I hope that explains it

Page 1 of 1