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MaplePrimes Activity

These are replies submitted by uomcsg


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.


Please check the edit I made.


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.


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

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