Hi,
does anyone know whether mecanum wheels are reversible? i.e. will the robot move if I push it using my hands ?
BR.
Lionel
OK, thanks.
Do you know if swedish wheels behave the same and where I can find some?
(Not sure swedish wheel makes sense in english, here is what I mean: crap.gforge.inria.fr/img/r129-6cm-poly-roller.jpg)
Sure. I am building a mobile platform that is supposed to keep close to the user as he/she moves. I am planning to make it autonomous, just like a regular robot, but first I need to make it “human-powered” (whitout motors), i.e. the user pushes the platform to move it.
I need this 2 steps design for prototyping issues.
So I am wondering if I can use the same wheels in both cases (human-powered and motor-powered).
solutions 2) and 3 (declutched) are exactly what I want to do as a 1st step. This is why I was wondering whether omniwheels would roll without any motor. Does your remark on 3 wheels vs 4 wheels still relevant if used on a free (no motor) shaft? Or may I use only 3 wheels?
Thanks a lot for your answers!
Do you have any products like the one mentioned with a load capacity of ca. 25kg (per wheel)? I could find some on your french website but no mention of load capacity.
ok, so I need 40 of these… 
Nothing stronger?
These wheels are different from the ones I mentioned (crap.gforge.inria.fr/img/r129-6cm-poly-roller.jpg). The problem is that I need to avoid vibrations, which will probably not be possible with your wheels as the distance between the rotation axis and the contact point with the ground is variable. Am I wrong?
OK. As far as I can see on the photos, all the wheels you have suggested have cylindrical outer wheels, right? No tapered ones?
Ok, so no solution for my need in your store?
I need to move audio-visual materials with the robot, thus vibrations will probably impair the system. I have found Robotshop to be the best place for robotics parts, and I’m afraid I will hardly find what I am exactly searching somewhere else.
Thanks for your support!
All this wheel talking topic gave me a great IDEA for a new project. I will keep you posted.
“Omniwheels”
The wheels around the circumference are not powered, so there is the possibility of slipping, depending on the configuration. If you have them set at 120 degrees (3 wheels) they should not slip, but if you have them all parallel, they will certainly slip. As with any wheels, you will need to overcome the motor inertia. Can you explain your project a bit more?
- If you choose a gear motor with a low gear ratio, it is quite likely that a user can rotate the motor manually.
- If you choose a higher gear ratio, consider creating a “fake motor shaft” which simply keeps the wheel in place, but allows it to spin freely.
- Another option is to offset the wheel (i.e. not directly connected to the motor’s output shaft) and then remove the link, allowing the wheel spin freely (a bit like a mechanical clutch).
Mecanum wheels are different and (from what we have observed) only move (properly) if they are powered.
Hope this gives you some ideas,
Three (120 degrees apart) or four (90 degrees apart) omniwheels would have the same effect if none of them are driven or directly connected to motors - you could move the robot easily by hand in any direction. Once you connected the motors to the wheels, you would need to push harder, or have the motors powered.
RB-Nex-09 (30Kg), RB-Nex-10 (40Kg), RB-Nex-08 (this last one is 20Kg, but best to use a wheel with a higher rating than 25Kg)
Omniwheels should always be used in pairs, and staggered in such a way as to eliminate vibrations. Some omniwheels are sold individually, while others are sold as pairs. In order to minimize cost, some outer wheels are cylindrical, whereas the the best design is to have them tapered.
Correct. Therefore even when back to back, they will not roll perfectly (some vibration).
The omniwheels are the best option, if you can live with a little vibration (about 1mm up and down). If you search online and find something more suitable, we invite you to tell us about it here.
You may be able to file down the out wheels yourself so they are tapered and therefore roll perfectly. The other option of course is to use multiple smaller wheels.