We are working on building a 3 wheeled scooter in which there are two large wheeles in the front that are powered and control steering with 1 smaller swivel wheele in the back for stability. so far we plan on using an analog joystick. Below is our supplies so far… also, would we be able to use the speed controller below as a micro controller as well… We plan on running 24volt batteries.
Yes, but it is very expensive. There are many alternatives. what kind of controller are you using? Can it interface with USB devices? Serial? Can it read resistance directly? Here is an interesting option for I2C.
Wow that looks cool and doable, but we don’t have much experience with these things. We aren’t sure if it would work with the board : http://www.robotcombat.com/marketplace_roboteq.html
(the top one in the left column). We really apprieciate any suggestions for other microcontrollers that might work for us.
Thanks!
Could you link to the exact speed controller you want to use to avoid confusion? The motor you have speced out has a stall torque of 110 Amps, if I’m reading things right, and the controller you listed only can source 7.5 amps continuous. Which means it won’t work very well at all.
As for motor controllers, 24V victors (VICTOR-883-24/24) from IFI would work, but you would need one per motor.
In addition to motor controllers, a micro-controller or other main controller should be used. For this the Arduino family of controllers would work. It offers I2C, analog, and PWM communications. However, 24V is too much for it, so a separate power supply might be needed.
Alternatively, You could 12 volt motors with 12 volt victors (VICTOR-884-12/12) and that would reduce the complexity some, but I don’t think CIMs can match that performance.
It is very possible that four CIMs, Four Victor 884s, and 2 AM tough box minis cost less than two NPC-T64s and two Victor 883s, while retaining acceptable performance. But this hasn’t been confirmed. I think that it’s worth looking int though.
EDIT: The Victor 885 might be a better match for the NPC motors.
This is not really an application in which you need to use advanced power electronics. A simple motor pair driven on a variable power supply (many possible options here) would work pretty well. It would also save you a ton of money.
I’m wondering how you’re going to lay out the wheels in the front…
Are they going to be spread far apart so that the scooter can stay upright while at a standstill, or will they be close together so that it needs to be in motion to balance?
I would love to see any sketches or designs for it!
Regarding variable power supply control.
This would provide a rather simple solution. I see this working well with a dpdt switch for forward/backward/center off with a throttle rheostat and a potentiometer for steering. The rheostat would be placed between the power supply and the pot. The output from the rheostat would connect to the center lead of the pot (wiper) and the two motors would be connected to opposite unused leads (the side leads). the dpdt switch would be connected to both battery leads in a H-bridge-like configuration (with out the break to power or break to ground options).
Thanks for all the information. We had to do a redesign with different (read cheaper) parts. instead of the 2 wheels in the front for power and steering we’re thinkking of using a bigger wheel in the back for power and probably manual steering with the front wheels. We’re working on an updated parts list now and shop be done today. And Centurion I’m also going to be working on the new sketches and will post them as soon as i figure how to on this forum.
@AdamHeard about how much run time would we get as is?
@PAR_WIG I attached some sketches i drew. They are very ruff but I hope they’re clear enough to understand. We’re going to be using pieces of corian and aluminum.
Edit: we are probably gonna use some old bike wheels for the front.
