i have an issue with my mecanum wheels it works perfectly for about 10 seconds then it works for 3 second stops like a twitching motion
specs
the hind mechs are strait motor connection the front ones are chained with 1:1 i am using speed motors
It could possibly be a problem with the tension on your chain…does the chain seem to bunch up or click when the wheels stop working?
I’m going to try to explain what you said.
You are using four mecanum wheels on your base. These wheels are driven by 393 High Speed motors. The front wheels are driven via chain at a 1:1 ratio, while the rear wheels are plugged into the motors directly. You are able to drive for approximately 10 seconds, then your robot seems to stop. After that, you are able to drive for another 3 seconds, after which your robot stops again.
If I’ve got that right, I would ask if you were running into sacks when that happened. If so, I would tell you what we learned earlier this year. Mecanum wheels don’t mix well with sacks. They get caught, and your motors eventually overheat trying to push them. Which is obviously a bad thing.
If you’re just driving around on an empty field and this happens, it’s probably a programming issue. Use the IFI Firmware Updater Bootloader on the Cortex, download the code to your robot again, retether the controller and then try driving while tethered. If it works then, connect via VEXNet. If it suddenly stops working, get new keys, because those are busted.
If I’m completely wrong here, explain it again and I’ll try to help.
There is no tension on the chain
We do not hit a sack and it can’t be the cortex because we have tried 2 of them
VEXnet Keys? Batteries? Controllers themselves?
Explain exactly what you have done so far.
We’ve tested everything bought new be net tried newly charged batteries and tried 2 controllers ie re uploading firmware
Is it possible for them to be to close ( mine are axel 12 holes axel )
Okay, let’s start labeling stuff.
Cortex A
Controller A
Cortex B
Controller B
Cortex A Tethered to Controller A –
Cortex A Tethered to Controller B –
Cortex B Tethered to Controller A –
Cortex B Tethered to Controller B –
Cortex A linked with VEXnet to Controller A –
Cortex A linked with VEXnet to Controller B –
Cortex B linked with VEXnet to Controller A –
Cortex B linked with VEXnet to Controller B –
Have you tried all 8 of those? How many VEXnet keys do you have? Are you using a partner controller?
Yes we have tried those we have 6
It’s not a micro controller or programming issue
It’s either speed motors don’t have enought power to power the drive or something
We also tried a dummy code with just tank drive still no fix
Put the motors for the left side on ports 2 and 3. Put the right side on 8 and 9.
That splits them across two circuit breakers, but 4 motors on the drive REALLY shouldn’t be tripping one. We did that all last year (Ports 2-5 for drive), and had no trouble at all.
We have tried that but it can’t be a breaker issue because when the breaker trips the motors shut down but in our case they twitch
Try changing your speed motors to torque.
Does your code by any chance include running the motors with input on both analog and digital channels? We had a problem earlier in the season somewhat similar to this when I did something stupid with programing our Mecanum.
Oh, and are you using a partner controller? If so, disconnect it and try again.
This isn’t necessarily a cortex/programming issue.
The first question I would ask is: How heavy is your robot? Mecanum wheels tend to put a lot more strain on the motors than regular omni-directional wheels (this is a reason why many teams who could use them don’t). I don’t expect that a medium-heavy robot will work too well with Mecanum wheels and a 4 motor 1.6:1 drive.
If you don’t think the weight of your robot is an issue, the first thing I would do it take all of your axles out of the motors and try spinning them by hand. Do you encounter any friction? If so, you may have to add more structure to your chassis to ensure the different pieces of metal stay square.
If there is no friction and you still encounter issues I would recommend either changing the motors to torque, or switching to omni-directional wheels.
Wait, did you say you were using the long 12 inch axles for each motor?
No. He said that there are 12 “holes” in the C-Channel between each axle.
I know, it’s hard to tell
If you guys want. I can ask him if he wants me to type the stuff he says on the forums, to have less confusion for everyone.
Are you guys on the same team? That would be fantastic.
Start over, and we’ll try again,
Not same team but same school. but ya I can help
try running the robot while holding it off of the ground( so the wheels don’t touch anything).
do the motors still stop?
if they do then look into the motors and how they are mounted. Is their any friction on the axles. ect.
if it is fine spinning above the ground, the there is simply too much stress on the motors and you may have to switch to regular speed 393’s.