Generate a trackmap with speed and g forces

[Gwen49]

Hello everyone,

I hope you are all great. I am writing down to all of you concerning a problem of mine. I am struggling to generate a trackmap based on Speed (m/s) and G-Forces on excel.
I followed a topic created 12 years ago but unfortunately it is closed :
https://www.physicsforums.com/threads/draw-map-based-on-speed-and-g-forces.518628/

Attached you will find my row data, there is just the beginning of the lap to minimize the file's size, I would be so happy to get some explanations, we never learn enough :-)

Thank you very much!

 

[berkeman]

Welcome to PF.

It's best not to attach files that can contain macros, since those can pose security issues. It's better to post a PDF screenshot of your file, to give others an idea of what you are doing.

Is this for schoolwork, BTW? Or is it for your own personal racing and tuning?

 

[Gwen49]

Thank you very much!

The file doesn’t contain macro, it’s a xlsx file.
In fact it’s just a file full a data no more, with car speed and g-lat forces.

From that, I would like to draw a track map.

This is for both! Thanks

 

[berkeman]

The file doesn’t contain macro, it’s a xlsx file.

Excel files routinely contain macros; I've used them myself to automate various tasks in spreadsheets. There is no way to know if there are macros (good or bad) in an Excel file prior to opening it, AFAIK.

This is for both!

Which both?

 

[A.T.]

I followed a topic created 12 years ago but unfortunately it is closed :
https://www.physicsforums.com/threads/draw-map-based-on-speed-and-g-forces.518628/

What questions are still open, that have not been answered there?

 

[jack action]

In your Excel spreadsheet:

• You are missing the time interval between each measurement;
• Are you sure the lateral acceleration is in m/s²?
• dA doesn't include the multiplication with the time interval;
• Vx & Vy have the wrong angle (they all have 1 rad or 89 rad);
• X & Y do not include the multiplication with the time interval either;
• X & Y have the velocity Vx & Vy multiplied by sine and cosine and they shouldn't;
• Might be better if X₀ & Y₀ both equal zero;
• Your graphs are linked to external data.

Because of the large values for R, this looks like a vehicle going in a straight line.

 

[Gwen49]

In your Excel spreadsheet:

• You are missing the time interval between each measurement;
• Are you sure the lateral acceleration is in m/s²?
• dA doesn't include the multiplication with the time interval;
• Vx & Vy have the wrong angle (they all have 1 rad or 89 rad);
• X & Y do not include the multiplication with the time interval either;
• X & Y have the velocity Vx & Vy multiplied by sine and cosine and they shouldn't;
• Might be better if X₀ & Y₀ both equal zero;
• Your graphs are linked to external data.

Because of the large values for R, this looks like a vehicle going in a straight line.

Jack, massive thanks for this deep analysis, I go back to work!

 

[Gwen49]

After working today on it, I feel I am not too far away from the right result.
The thing is, I don't know how to figure Ao out. As I don't know Ao and A, I can't solve the equation. I feel like I am stuck.
Is there another way round to know my Ao ? As normally i should be able to draw a trackmap from G forces and Speed I guess there is something I don't get here
Thanks!

 

[jack action]

A is the angle of the car with respect to your X-Y plot. It is not the steering angle.
A₀ is the initial value.

A₁ = A₀ + dA₀
A₂ = A₁ + dA₁
A₃ = A₂ + dA₂
...

The same concept goes for X and Y.

 

[Gwen49]

Jack,

Big big thanks for your crucial help. I manage to finish the tool I wanted to do.
You are a genius!

See you soon!

 

[palagi]

Can you post the final version of your spreadsheet? Also, can there be a correction factor applied to lateral G to join the ends of the plot? I assume these are the same position on the track (start/finish)... I recall about 25 years ago, PI datalogging software would automatically do this to represent a track map.

I also notice that your plot is a mirror image of the actual Pau track. Again can this simply be corrected by multiplying Lateral G by -1?

 

[berkeman]

Welcome to PF.

Can you post the final version of your spreadsheet?

@Gwen49 has not been back since June of 2023, so about a year. Hopefully he gets an e-mail notification about your post (or my tagging him) and comes back to respond.

 

[palagi]

Thanks, I'm no maths genius,, just a hack programmer that tries to solve such challenges by adapting other smarter peoples stuff. I am building a dash logger with my son for his track bike and would love to be able to plot track maps. GPS data is not fine enough and this method being tied to distance enables overlay comparisons of data from one lap with another with an indicator on a map for reference.

 

[berkeman]

Thanks, I'm no maths genius,, just a hack programmer that tries to solve such challenges by adapting other smarter peoples stuff. I am building a dash logger with my son for his track bike and would love to be able to plot track maps. GPS data is not fine enough and this method being tied to distance enables overlay comparisons of data from one lap with another with an indicator on a map for reference.

What is your data acq suite on that track bike? I'm sure you have speed, but how do you handle the combined g-forces and bike lean angle?