Also I want to make my robot hard to push from the sides… I am thinking locking an additional pair of omni wheels centered in the middle of the chasis, or maybe the same thing except with traction wheels. What would be the best way to go about making a robot that won’t be pushed around?
Yes, but there are also multiple options to fix you tipping with having your whole bot aluminum. It is just one solution I gave. Anyways I don’t think you should worry too much about stain on the motors because of how powerful and plus just by looking at your robot from that first pic it is very light.
Even though they are “light” to you, they aren’t light on a robot. Momentum primarily and many other factors impact the performance of the robot substantially. You need to take careful consideration of this when making a design. I’m not saying the v5 motor can’t handle it, but I am saying that it is important to consider everything in order to optimize performance.
You should not think like this when designing anything. Just because the v5 motors can handle some friction and various other forces does not mean you should lack on basic design principles. That is just bad engineering (imo).
thanks for saying that a 4 motor drive is a pre requisite in order to be competitive lol. My school team is very new… I am the senior member and don’t even know that much lol. Anyways are there any other almost pre requisites that I should know about? I’ve learned to always use c channels and never rails… lock bolt aluminum… two c channels should go across entire robot… anything else worthwhile?
It kind of depends on the robot. Try and look for various other kinks in the robot and try to solve them. Your robot is never “Finished” you should always be able to find a way to make your robot better. If you can’t find one, then you aren’t looking hard enough.
I really like this chassis set up (skip to around 5:30). It prevents pushing from the side while also maintaining maneuverability. This is because it maximizes traction.
Also what are your guys thoughts about using stand offs for essential parts of the robot? I find that they lossen pretty easily and I am trying not to use them too much but it’s hard
as you can see from the photo my lift is being elevated by stand offs and I am wondering if this is a janky building practice
It is okay to use standoffs, but I would strongly recommend using loctite or off-brand equivalent to keep them from unscrewing.
yeah that was actually the video that made me realize I should do it for my robot as well… thanks!
What do you mean by using loctite to keep them from unscrewing? Is it using nylon spacers on either side of the stand off?
If you can, have where the lift is built get a c-channel long enough to reach your chassis. And make sure it can at least line up with two hole going down if you know what I mean. This can help make is a lot more stable. And if you are having problems with standoffs loosening you should add more bracing to that piece and then you can also get locktite.
No, it’s…using loctite. (image for reference)
(Be sure to use the removable kind and not the one you need explosives for.)
(And yes, blue 242 comes in a red tube; don’t ask me why )
Locktite is a substance you can buy and put it on bolts and stuff like that. It enhances the friction to make it harder to become lose.
wow I had no idea, thanks guys! I assume I use this once ive finalized my build because this looks like it will be hard to come off
Also the middle traction wheel 7700R uses is a sprocket surrounded by a weird material… you don’t happen to know what that is do you?
It is a traction wheel piece. You can buy it off the vex website. There are many different ways people do that as well. Some have gears and zip tie I think foam and rubber bands to it as well. That is another way.
So I have this ideology when I build. I call it “The Pillars of Build Quality”:
Rigidity/Durability: Can the system withstand competition defense, long durations of practice, and general real world forces? A general rule of thumb, if you can manually move/bend something with your hand, it probably needs to be reinforced.
Symmetry: This one is very very important. Obviously there are certain cases where symmetry cannot be preserved. This has to do with odd numbered items such as the battery and brain as well as intrinsic qualities of certain subsystems. But for the most part, is the robot symmetrical? CAD is very useful for this because it ensures symmetry. You can’t just bend something into place with CAD, and it ensures everything is in line.
Friction: is everything that is supposed to move on the robot able to do so freely. There should be minimal resistance on anything that moves. Otherwise, that tells you something is not in line (particularly with bearings). Take the time to realign that part with the proper spacing.
Slop: This one is a bit tricky to assess. Slop is the deadzone with all moving parts. Particularly with gears. Usually, gears can move for a small interval before they engage with the axle. This is not limited to gears, but is an inherent problem. This can be solved with screw joints, among various other techniques. Slop is not a good feature.
Functionality/Accessibility: How functional is the subsystem and all the components that make it up. Can said part be improved in any way? A good way to assess this is by analyzing the smoothness of the subsystem with slow-motion video. Minimize as many vibrations as possible (this should happen naturally with good build quality). In competition, you also want to be able to access certain parts in the event of failures. So, make things such as a motor or sensor accessible for change/replacement. Not sure if this category should be separated, but I think they are similar enough to be combined.
I hope this helps
thanks this is exactly the next level building philosophy that I have been looking for. Being able to fix small details of the robot like you focus on is where I want to get to so thanks again