Showroom 2DOF project (with rotation in future)

Hello everyone !

I from Argentina. I have a static copckit and it's time to move to the next level !.

I am currently building my first 2dof, with the option of adding rotation to simulate traction loss.
I am using the following hardware:

1 x Arduino Uno R3
2 x Moto Monster (one by motor)
2 x 800W PSU 66A (one by motor)
2 x hall sensors Ss-495
4 x neodymium magnets
1 x truck Kardan
2 x 12 Vcc motoreductor 150W (1:25) - 120 RPM


The day that this works I will upload video !
Cheers


Base:


Skeleton:


Kardan holder:


Motors:





Current progress:

More progress...

DIY hall pots. They work fine, but I can not get the range 0-1024. The best is range: 10 - 960.





next step: assemble and test with simtools

Hi all.

I show the current status

Box with moto monster, arduino and psu's;






In action:



Let's go for more!

Hi!

Pot scale is not problem, i also tested diy-hall. Your fast motors with such a sort lever from pivot point, gives you very fast moves.... maybe even too fast, you decide I think the structure may need little more strengthening, it may wobble under pressure. Nice job anyways!

Thank you dr.feelgood.

I decided to reduce the pivot point, because when I sat down I could not move.

I lowered the pivot to 6.5cm and works better. I must also modify some things more of the structure, but the anxiety wins me

@dr.feelgood, you're right.

It looks like I made a hammock, it does not stop swaying. I'm going to have to strengthen the structure.

Thank you for your observation

Hello people.

The moment has come !. I have assembled all the structure and started the engines!




But when I sat down, many things happened:

1. The motors do not have the strength to move me (I will try to reduce the pivot)
2. The potentiometers (DIY hall pots) do not give correct values (we will have to redo them)
3. When PWMmax is set to 210 or more, the PSU turn off (I want to cry).
4. One motor loose precision on your axis (see video)



In other words: I am a little disappointed. This is going to take more time than I thought.


I will continue when I have time

Hi! More tuning and slower movements may help you out.

I started initial testing with car battery. Later when switching to PSU, i had similar problems with shutdowns. BUT it happened only while sim was not loaded and it happened because of too sudden moves! I haven't had similar problems when i'm on the sim.

Your motors are very fast and they probably need some more tuning with SMCUtil. Too bad that there already is some play in gears, don't know if that is fixable... And do as @noorbeast says, it will help.

But please, don't give up !!!

Thank you noorbeast, yes, I will try to reduce the pivot.

dr.feelgood, I called the motor supplier, he tells me that I have to disarm the gearbox to see what it can be.

I am analyzing the possibility of buying a car battery of 80 Amperes + a battery charger. It will be good idea to feed the 2 motors (3 in a future). Do you know if the charger can be used while I am using the sim?

While I am going to do the hall pots again (here in Argentina unfortunately they are not achieved)

I will not give up.. I keep trying

Bravo!

Just keep in mind that charging can produce exploding gases, so no sparks and good ventilation is needed. I myself did not charge while testing, charged afterwards... 4amp charger fills 80Ah battery in ~20 hours or so...it depends how juice you use while driving.

Thank you dr.feelgood. Your information helps me a lot.

I'm seeing that car batteries have a coefficient called "Reserve Capacity". In other words it indicates the time of discharge.
I estimate approx. 2 hours with a continuous use of 30Amp. Sounds interesting.

Thanks, again!

Hi guys!

I have been able to solve the problem of the paly on the gears.
The problem was in the key, (here it is called "chaveta"). I add photos in case someone has the same problem. I replace it.





next step: remake of DIY hall pots

Como estas.
Te comento, lo que me parece que podrias mejorar:
1-Comprate un par de potenciometros bourns con eje metalico, 200 mangos cada uno y te olvidas de los inventos de los hall caseros..
2-Tenes muy poca reduccion, esos motores estan muy bien, pero una reduccion 25:1 es muy escasa, tendrias que tener el doble.
3- La estructura es muy debil, se te va a doblar y por ende perdes exactitud en los movimientos.
4-Subi el agarre de los motores a la estructura por encima del eje de gravedad, te va a ayudar a no cargar tanto los motores con esa relacion, o pasa los motores adelante y lo mismo, que agarren mas arriba.
5-Compra una fuente para leds de 12v y suficiente amperaje, son menos delicadas que las de pc, o compra una fuente de servidor, que son de mucho mejor calidad que las de pc comunes y saltan algo menos.
Cualquier cosa chifla


English laziness, google translate:
How are you.
I tell you, what I think you can improve:
1-Buy a pair of bourns potentiometers with metal axle, 200 mangos each and you forget of the inventions of the homemade hall ..
2-You have very little reduction, those engines are very good, but a 25: 1 reduction is very low, you would have to have twice as much.
3- The structure is very weak, you will bend and therefore lose accuracy in the movements.
4-Up the grip of the engines to the structure above the COG, it will help you not to load both engines with that relationship, or pass the engines forward and the same, to grab higher.
5-Purchase a source for 12v leds and enough amperage, are less delicate than the pc, or buy a server source, which are much better quality than the common pc and skip something less.
Ask anything you need.

Hola mariano68

Voy a intentar una vez mas con los hall, sino voy a ir por los potes que me decis.
Si, cuando compré los motores no presté mucha atención. Ahora cambiarlos sería volver a poner $$. asique,. intentaré con los que tengo.
Con respecto a la estructura, tenes razón. Ya la estoy reforzando
Voy a probar lo que me decis..lo de subir el agarre, también voy achicar el brazo de palanca con respecto al eje. a ver si ayuda.
Mas fuentes!!!.nooo, ya compre dos. Si sigue saltando compro una bateria de 120A y un cargador y listo.

Gracias por toda la data,
abrazo



Hi Mariano

I will try once more with the hall pot.
Yes, when I bought the motors, I did not pay much attention. Now change them would put back $$ so, I'll try again with them.
With the structure, you're right. I'm reinforcing it.
I'm going to prove what you say about raise the grip, I'll also shrink the lever arm with respect to the axis. To see if it helps.
More PSU!!! nooo, I already bought two. If I continue with the cuts, I buy a 120A battery and a charger.

Thank you for all the information,
hug

Hi all!

There were only multi-turn potentiometers in the store. I bought the 5K - 10 turns.
When using only half a turn, the values read by arduino go for example from 500 to 550 (for 180 degrees)

I made some changes to the SMC3 script.
I understand that this way I will lose a lot of precision, is it true?
Is there any way to fix this?

curious how does a "key" prevent any play in the gear box itself ? hrmm i see 2 keys on that Axle,....interesting, so there's a keyway inside the gear box on the main gear i will assume.

Exact @Nick,

Inside of the gear box there is a slot where the key engages.
(Sorry if the translation is not the better)



Even changing the keys, the play continues.
Therefore I am determined to apply a soldering point on the axle. Sound very bad?

I wouldn't suggest welding anything, Not a wise idea.

The Play is needed for proper gear operation on the worm gear in general. If you apply a proper 1-2% weight bias towards the rear on On your motor's (pending the configuration) You shouldn't notice this play in the box very much, if at all.

It is very difficult to see, but I think the play is between the ax and the crown (I do not know how it translates).

Listen it in this video.