Problem with Section 7.1 Task 5 of Simscape onramp

Although I correctly configured the model blocks and parameters accordingly to the directions, the training evaluation said my output did not match the answer. It prevents me from proceeding to the next task.

Here I attach two snapshots of the evaluation plot of Section 7.1 Task 5 where the problem occured.

The first picture shows comparison of the signals spanning to the end time (10sec). It looks to me exact agreement between the requirement and my signal, but it indicates slight discrepancies in the beginning of simulation (from 0 sec to around 1.0 sec) shown by the red dots. Due to these errors, the evaluator says my signal is incorrect.

The second picture zooms into the details of the red dots. It looks to me my signal has a slight delay to the answer.

I confirmed that my setup is consistent with the directions and the results unchanged even after several retries from the beginning of Section 7.1.

I am wondering if there is another parameter to be adjusted, which is not explicitly directed.

Can I have your help for solving this problem?

[Jan Kirner]

I have the same problem. Best regards.

[Lianna Cubias]

@Joel Van Sickel

i seem to be experiencing this issue and have consulted many but have failed to find anyone with a solution or explanation as to why this is happening. Your answer for the thread about the problem with Simscape Onramp task 9 helped so can you offer some insight here, please?

[Lianna Cubias]

Figured it out! Finally!

Do tasks 1-5 as instructed. All that is correct. Before running the model in Task 5 try this:

Check the settings on the "Rotational electromechanical converter" block that your "ideal rotational motion sensor" is connected to. Go to the "Variables" tab, check the override box for "Angular velocity" and set priority to "high". Everything else, leave it the way it is. Then run the model. This worked for me because I was having this exact problem.

[Philipe Doughty]

It worked for me by setting the priority of angular velocity to low.

[玄人 市川]

Thank you Lianna and sorry for my late response although I originally started this thread. I have just tried your practice and it did work for me.

[Amanullah S]

Thank you I too strucked and rectified after giving priority as low

[Eric Guil Vidal]

For me worked setting "low"

Answer 1

[Joel Van Sickel]

I am pasting Lianna's comment here as it is the solution.

Lianna Cubias on 7 Aug 2021 at 9:16

Figured it out! Finally!

Do tasks 1-5 as instructed. All that is correct. Before running the model in Task 5 try this:

Check the settings on the "Rotational electromechanical converter" block that your "ideal rotational motion sensor" is connected to. Go to the "Variables" tab, check the override box for "Angular velocity" and set priority to "high". Everything else, leave it the way it is. Then run the model. This worked for me because I was having this exact problem.

[Muhammad Amirul Alif Zakria]

Thank you for the tips, it worked for me

[Kiril Nikolov]

For me it did not work when I set the priority to high, it did work when I set it to low, however...

[Melissa Niesen]

Mine also only worked when I chose "low" rather than "high" for the angular velocity override.

[Osmar Tormena Júnior]

I can also confirm it only works with low priority.

[francisco sabugo]

Thank you!! it worked for me by setting the priority to low of w in the "Rotational electromechanical converter"

[Khaled Alnajjar]

For me it did not work when I set the priority to high, it did work when I set it to low, however...

[Daniel Hilal]

It also worked for me with the low priority (only for the angular velocity)

[Marc]

Worked for me with "low" priority. Frustrating as hell though! Dang it Mathworks! Put this in the instructions.

Thanks to all of you who found this out!

[Paolo Galimi]

Here, too, it worked with with Angular velocity set to low (tried prio. high and constant changed to 500.3745 w/out success). My plot had no error red dots whatsover. The Signal requirement (orange) and My Signal (blue) were just the same even with a zoom in. I am running R2021b on linux64. Thanks for figuring this out.

[DHUSHYANTH S]

It worked for me by setting the value of angular velocity to low. thank you @Paolo Galimi

[Philipe Doughty]

It worked for me by setting the priority of angular velocity to low.

[玄人 市川]

Thank you Joel for your advise. Sorry for my late response although I originally started this thread. Changing priority to high for Angular velocity did work for me. Just wondering why it still does not work for some people and the opposite setup works for some of them...

[Ali AJDER]

In my case both setting the priority of angular velocity to high or low did not work. I also tested the other combinations for torque and angular velocity!

[Ali AJDER]

I tried again and now it worked by setting the priority to low of the "Rotational electromechanical converter".

[Paphon Rattanadumrongpinyo]

I can't whether it changes to low or high

[Rosendo Valdes]

Thanks, when I change the constanto to 500.3745, and did the instruction

[Chris Turner]

I had to do both, as well. Thank you all for posting your solutions!

[meron eyasu]

Thanks Joel worked for me "High"

[Daniel Mejia]

No me funciona nada, ni en alto ni bajo, ni cambiando el convertidor rotacional. nada

Answer 2

[Orkhan Alikhanov]

It only worked for me after I set priority to "low" in the "Variables" tab of "Rotational electromechanical converter" block.

[Douglas Johnson]

I had to set the priority to "low" and change the constant to 500.3745

[Jichao Fang]

Douglas's solution worked for me.

[Puskar Neupane]

Orkhan solution works for me

[Karl Frode Ring]

Me also

[Mohit]

thanks for the solution, worked for me .

[Eric Liu]

Thank you for the tips, it works for me

[Philipe Doughty]

It worked for me by setting the priority of angular velocity to low.

[玄人 市川]

Thank you Orkhan. Hmm.. as the other people advised to me, changing the priority to "HIGH" only worked for me.

[俊 井]

Me too.

[Shafie Mohamed Shafie Hassan]

yes , set the Angular Velocity in the 'variables' section of 'rotational electro mechanical converter'MAT

that should work

[R2021b]

[Kartik]

Thanks, After setting priority of Angular velocity to "Low", it did worked.

Answer 3

[Alisha Schor]

If possible, please update to R2021b, Update 1 or newer. This should resolve the issue without having to change any block settings.

Answer 4

[Justin]

An error will occur that resets the values of the PID block.

Change the PID back to PI.

Change the Proportional (P) value from 1 back to 1e-6.

Change the Integral (I) value from 1 back to 5e-3.

Change the Sample Time (-1 for inherent) from -1 back to 0.05.

This glitch is frustrating. I question the Previous solutions.