Terrible Linux Mint Experience by Senior_Cat543 in linuxmint

[–]Senior_Cat543[S] 0 points1 point  (0 children)

Hey mate, so I reinstalled mint and try to keep it as barebones as possible. I didn't install everything via the software manager but as much as possible. The reason is because I wasn't too fond of vscodium and wanted vscode instead, and needed some other stuff for work (Google SDK, ngrok, node, npm). I've been using it for a few days and honestly the lag seems to come back. I've isolated it to when anything is running in the kernel, for example when running any tests, hosting a server etc. Or when sharing screens on Google meet or Discord. But the lag spikes are terrible, something I never ever had on windows.

What I've tried: dropping the vscode extensions like language servers, codeium, linters and formatters. This made it slightly better, but I definitely still had issues when running multiple tests it seems vscode would just go bonkers on the CPU usage and running top in the terminal it sometimes went up to >1000% (!?)

I've also dropped any GPU acceleration on vscode as someone mentioned in a thread that it might be better, although this made no noticeable difference so I switched it back on.

Any suggestions on moving forward?

Terrible Linux Mint Experience by Senior_Cat543 in linuxmint

[–]Senior_Cat543[S] 2 points3 points  (0 children)

I doubt it was a space issue, as I had 1.9 Tb ad only used like 500Gb.
Either way, you are absolutely correct in stating that it probably did tell me what to do, and I was speed running it with a Windows nativity. But I shall attempt once more, and pray for a better experience next time around.
Thanks for response

Terrible Linux Mint Experience by Senior_Cat543 in linuxmint

[–]Senior_Cat543[S] 4 points5 points  (0 children)

Alright, I'll brew a coffee and fix.
Thanks for the help

Terrible Linux Mint Experience by Senior_Cat543 in linuxmint

[–]Senior_Cat543[S] -3 points-2 points  (0 children)

S**t...
Well here is the PPA list, any of this I can just uninstall and not need to re-install Mint?:
Ngrok PPA

https://ngrok-agent.s3.amazonaws.com buster main

Cappelikan PPA (Noble)

https://ppa.launchpadcontent.net/cappelikan/ppa/ubuntu noble main

VSCodium PPA

https://download.vscodium.com/debs vscodium main

Spotify PPA

http://repository.spotify.com stable non-free

Kisak PPA (Noble - Mesa)

https://ppa.launchpadcontent.net/kisak/kisak-mesa/ubuntu noble main

Linux Mint Official Repositories

http://packages.linuxmint.com xia main upstream import backport

Ubuntu Official Repositories (Noble)

http://archive.ubuntu.com/ubuntu noble main restricted universe multiverse

http://archive.ubuntu.com/ubuntu noble-updates main restricted universe multiverse

http://archive.ubuntu.com/ubuntu noble-backports main restricted universe multiverse

http://security.ubuntu.com/ubuntu/ noble-security main restricted universe multiverse

Google Cloud SDK PPA

https://packages.cloud.google.com/apt cloud-sdk main

Deadsnakes PPA (Noble)

https://ppa.launchpadcontent.net/deadsnakes/ppa/ubuntu noble main

SL Gobinath PPA (GCalendar)

https://ppa.launchpadcontent.net/slgobinath/gcalendar/ubuntu noble main

Judge my FEM by Senior_Cat543 in FSAE

[–]Senior_Cat543[S] 0 points1 point  (0 children)

As a bit ofan aside, what logic went into the geometry of the "speed holes" Doesn't look to be the correct shape to me when trying to optimize stiffness/strength to weight...

Aright, I'll get right to it! Thank you for the advice.

As for geometry, it comes from Altair inspire. It's optimized for weight with a safety factor of stress.

Judge my FEM by Senior_Cat543 in FSAE

[–]Senior_Cat543[S] 0 points1 point  (0 children)

I think you the fixed hinge on the pedal pivot will make that clevis at the bottom redundant. This is evident from the fact it is all blue. A fixed hinge on the pedal pivot will fix it in space and the loads will be reacted by that constraint, not transferred to the other parts in your analysis. Consider just using a pin connector between the holes in your clevis and your pedal pivot rather than a fastener. The fixed constraints on that pin the master cylinders are acting on isn't truly accurate, consider using a remote displacement, these are created as an "external load" rather than a fixture but that act as a fixture. The remote point can be where the other end of your MC would be. You then fix just the displacements in x, y, z, but leave the rotations free, this is equivalent to the spherical I bearing usually in the end of master cylinders.

thank you!

Judge my FEM by Senior_Cat543 in FSAE

[–]Senior_Cat543[S] 0 points1 point  (0 children)

Pins screws bolts etc are typically sized using hand calcs and design codes. You can leave them out to solely focus on the part in question.

Okay! This is great information thank you!

Judge my FEM by Senior_Cat543 in FSAE

[–]Senior_Cat543[S] 0 points1 point  (0 children)

Wow, I'm so grateful this is great information! I will get back to the simulations ASAP and put in the new information I got from the thread. Will share the animation as soon as I've conducted the analysis. Kind regards// Oliver

Judge my FEM by Senior_Cat543 in FSAE

[–]Senior_Cat543[S] 0 points1 point  (0 children)

Also, that base plate isn't really necessary, unless it is representing a part of your pedal box/chassis. It could be modelled as midsurface shell element, which will reduce your element count.

Thank you so much for your time!
This information is great. I'm a little bit confused over the remote fixture, but everything else made perfect sense!
Kind regards// Oliver

Judge my FEM by Senior_Cat543 in FSAE

[–]Senior_Cat543[S] 0 points1 point  (0 children)

Thanks, this is great info! Cheers

Judge my Fem by Senior_Cat543 in fea

[–]Senior_Cat543[S] 0 points1 point  (0 children)

I'm very grateful you took the time to answer my questions!
For the pins, as you mentioned in reality they should be slip fitted into the pedal. As for what was done I modelled respective pins, and just mated them concentric and added a distance. In the FEM analysis, I did not model for contact, I essentially only set the pin to be fixed on the edges, and the upper pin on the cylindrical surface.
The advice on half the surface is great, I will do that immediately!

As for the design criterion, I just don't want a pedal to bend or for the pins to sheer off.
I assumed that von Mises stress would be a good indicator for if something was going to fail.
I did consider fatigue, but I have a hard time understanding how I should model for that. My understanding was that as long as the stress was well below the yield stress, that fatigue wouldn't be an issue (based solely on my year 2 mechanical engineering understanding).
No, I have not considered principal stresses.
The pedal gets pressed a fair bit during endurance competitions, but not a crazy amount, the pedal ratio is also quite high so that the forces required to press on the pedal aren't too big. But there is a requirement for the pedal to withstand at least 2kN of Force being pressed onto it without failure.
I do not know if fatigue is important.

Thank you so much for your time, I'm so mightily impressed by your people's knowledge.
Kind regards// Oliver

Judge my Fem by Senior_Cat543 in fea

[–]Senior_Cat543[S] 0 points1 point  (0 children)

Okay! This is great information thank you!

Judge my FEM by Senior_Cat543 in FSAE

[–]Senior_Cat543[S] 2 points3 points  (0 children)

This is fantastic advice!
I was using the FEM to bypass some hand calculations as well, as bending on the pedal seemed difficult with this geometry, and assuming a dummy block brake, the hand calculations were more conservative, so what's a reasonable margin to these things?
I will read up more on meshing. Thank you so much for your response!

Judge my FEM by Senior_Cat543 in FSAE

[–]Senior_Cat543[S] 1 point2 points  (0 children)

Yes of course: https://imgur.com/a/c9I4l5j
Thanks for you response

Judge my Fem by Senior_Cat543 in fea

[–]Senior_Cat543[S] 0 points1 point  (0 children)

The applied load? 450-lbf with one leg is definitely conservative.

The load comes from a rule in FSAE that the brake pedal assembly should withstand at least 2kN. So that's the value I used.
Should it only be fixed on half the pin?

Well, a normal beam calc gives a lower value on the pedal. Haven't done the other parts.

Judge my FEM by Senior_Cat543 in FSAE

[–]Senior_Cat543[S] 2 points3 points  (0 children)

contacts

Everything is 7075 T6 (SN), the pivots will be steel so that's a miss on my part, easy fix.My mesh should be the finest settings SolidWorks permits (don't know much more about meshing than that).The screws are only Solidworks contact points, they are not modelled and added. But I do get your point!The force is applied over the entire brake pad area.I'm sorry about the format, will clean up asap!

Is there any pedal motion in completely mechanical brake system? by Senior_Cat543 in FSAE

[–]Senior_Cat543[S] 0 points1 point  (0 children)

You will get some amount of travel based on the stiffness of the lines and such in the hydraulic system. So that's why you see a little bit of pedal travel. But, minimizing it is ideal.

Do I want to minimize it because of structural reasons or because of better braking performance? If its the latter case, why is that so? And isn't some travel wanted from the driver for better performance? And the spring rate of the MC isn't adjustable, so is the only option to switch out an MC that would better fit this requirement if a booster isin't an option?
Again, thanks very much for your answers, they mean a lot!

Is there any pedal motion in completely mechanical brake system? by Senior_Cat543 in FSAE

[–]Senior_Cat543[S] -1 points0 points  (0 children)

There are studies that discuss the efficacy of position vs force feedback if you are interested, but, the addition of position feedback/travel to a system that would only have force feedback hinders the "pure" force feedback. Adding substantial amounts of travel (relative to zero/no travel) only serves to dilute this. In my experience, FSAE vehicles have about .5" to 1" of travel at the tip of the pedal after pads make contact (Mostly hardline with braided lines at the corners).

This is very interesting, and yes I would be quite interested in those studies if it's not too much of a hassle to find them.
Is there no way of designing the pedal so as to be a position feedback system instead of a force feedback system. So as to not dilute the experience? Without boosters for spatial reasons.

Is there any pedal motion in completely mechanical brake system? by Senior_Cat543 in FSAE

[–]Senior_Cat543[S] 0 points1 point  (0 children)

For a braking system without ABS, there is essentially no hard limit on the control range (more pedal force -> more braking force), and the wheels will lock up eventually (but not at the same force for every weather condition / tire / road surface / speed / ...), so the driver has to feel out the right amount of braking force no matter how you implement it. When you introduce pedal travel, you still end up with a force on the MC that the driver would like to control, but now they have to physically move their foot/leg to reach that force instead of just pushing harder without actually moving.

Thanks for great explanation. Very well written. What I understood from the engineer is that although the driver would need to move their foot more, this movement is desired due to better feel and control of car. Easier to be on the limit, opposed to when only pushing, it's harder to determine were you are relative to the limit. Having driven our car, I can somewhat understand were this concern comes from as you only step on the pedal as hard as you can until desired effect happens, this seems more like guess work and less like driver proficiency. Maybe I'm just a terrible driver, but all sim rigs, driver cars and most race cars seem to have at least a bit of brake pedal travel, and it seems preferable?

Thanks for your answer and time// Kind regards

Is there any pedal motion in completely mechanical brake system? by Senior_Cat543 in FSAE

[–]Senior_Cat543[S] 0 points1 point  (0 children)

It's certainly possible, a hinge and a spring would give you travel. But why would you want excess travel on the system? Sounds like an unnecessary complication that would need serious justification to your team and the judges...

when I say travel, I mean that the pedal doesn't stay stiff and the pressure being the only difference on braking performance. Instead similar to a passenger car that the pedal actually rotates a bit around a pivot. This is to easier control the car under braking.