Hello,
First i’m French so sorry for my English.
We have the 8" Mecanum HD Wheel Set. I would like the reducer and the motor in order to creat a movement of 0.5m/s with 250kg per wheel. Can you determine this elements that I need for this job?
Thank you for your answer.
The platform you have would essentially weigh 1000Kg? If this is the case, it’s the size of a regular passenger vehicle. Unfortunately we do not have any motors for a robot that size at this time. Are you certain that 8" wheels can support that weight?
It’s the Mecanum wheel that I found on your website :https://www.robotshop.com/en/8-mecanum-hd-wheel-set-2-left-right.html
That is indeed quite a wheel, and do apologize (250Kg ~550lbs, which is beyond the breaking point of the wheel). Can you describe your application a bit more?
What items do you have besides the wheels?
The order it’s to make a robot (80cm*80cm) with this mecanum wheel. I want to put a maximum load on my robot. Not realy 1000kg but maybe 500-600kg. With 500 pounds per wheel this should be possible. Now I need the motors and the reducers for each wheel.
600Kg is still almost the weight of a passenger vehicle (for example a Smart weights 816Kg). You will need very powerful drive motors, especially in a Mecanum setup. where friction is greater. Unfortunately at this time we do not offer any gear motors that powerful. The most powerful we offer is the CIM and a high reduction ratio:
robotshop.com/en/catalogsear … t&dir=desc
Four of these gear motors might be good for up to around 150Kg.
Ok but for my robot, I don’t need to go at 90km/h. I juste want something like 0.5m/s (2km/h). With this DC motor and a thoughbox?
At 500-600Kg… not very likely.
I don’t understand because when I use your dimensioning tool (andymark.com/TB3-p/am-0977.htm?CartID=2)
It’s should be ok no? Maybe I don’t understand somethings.
The issue is that there is no slope at all, therefore the robot simply needs to maintain constant velocity.
With a robot this weight on a flat surface, additional factors like inertia and friction would need to be taken into consideration, which are not in this simplified model.
Note that in all likelihood the robot will need to overcome some angle, so you might want to factor in 10%.
OK thanks you. So if I put 5% for the angle (10% it’s to much) I have 41Nm (without inertia and friction) but with your CIM motor and the gearbox 51:1 I have 62Nm. It seems to me good.
You have the controlers for this motor?
The CIM motor has a stall torque of 343oz-in (2.42Nm). Note that you should never operate close to the stall, but instead around 1/4 stall, so the CIM motor alone would be rated around 0.6Nm. As such, you would need a ~70:1 (or higher) gear reduction. The CIM consumes around 20A at max efficiency and 68A at max power (you will likely be closer to max power). Therefore you would need a 70A (or higher) brushed DC motor controller:
robotshop.com/en/high-power- … llers.html
Ex: robotshop.com/en/vyper-120a- … =RB-Rop-12
When you first use the motor, be sure to measure current. There is thermal protection.
Hope this helps.
