look up cim motors. We use them in large (130 lbs) robots all the time, and i have no doubt that with a little gearing they would support 200 quite well. using Robotshop’s drive motor calculator, and a listing of one of these motors, i have calculated that, geared correctly, two of these motors would push 200 pounds up a 45 degree incline at 5 miles an hour, though i amnot quite sure of that part. after doing these calculations, it strikes me that 1 motor might suit your needs powerwise. if you need to be using two for balance or whatever, it would be up to you about whether to look for 2 smaller motors. it also strikes me that one of these motors uses 20 amps, so to run it for, say, 2 hours at a time, you’d need a 40 amp hour battery, though i’m not sure what kind. perhaps a motor scooter battery. anyway, you can find a very cheap controller for these things. If you have any other questions, feel free to message me, I may be able to help find answers to your questions.
-Ryan
Hi snokol,
Welcome to the RobotShop Forum. Your post is actually very much on topic. You should consider a motor controller with analog input so you just need to rotate a knob to increase / decrease the speed. You would need to have an idea of the maximum continuous current required by the motor in order to choose the controller. Mechanically gearing down the motor would be your best option (say, a 4:1 chain / sprocket combo) though the motor controller should be able to reduce the speed down to what you want. Your main issue will be how to mount it all to your kneewalker.
Hope this helps,
The motor in the link seems to already have at least a 2:1 geardown, and the sprocket is intended to mate with a larger one, further increasing that gear down. You should be able to use the two together and you would need to find a motor controller which can be operated at 24V and whatever max current the motor consumes.
Sincerely,
Looks good for a small to medium sized combat robot, but likely not enough to move a human. There’s no power or hp rating, so it’s difficult to know.
You might consider trying to find two old electric bicycles (ideally identical), hacking them apart and designing a custom frame. I know here that you can get an actual new electric bicycle for ~$250 from Canadian Tire (includes everything you’ll need except for a custom frame).
The noise is likely coming from the rest of their setup - not from the motor itself. Electric motors usually run fairly quietly (not perfectly quiet though). Two geared CIM motors can certainly be used to move a full sized adult male.
No - unless you want to add some autonomy to the system. You only need an analog dual DC motor controller powerful enough to run each of the motors. The “analog” part means the speed and direction can be controlled via a potentiometer (or a voltage between 0 and 5V with 2.5v being neutral).
Most of the analog DC motor controllers have an onboard 5V regulator, so the voltage across the potentiometer is always 5V, regardless of the input voltage. To have the motor’s speed correspond or be related to your speed, you would likely need a microcontroller to act as intermediary (and of course you would need to program it as well).
Take a look at this article: Choosing a Motor Controller. You need to choose a motor before you choose a motor controller; the more powerful the motor, the more expensive the motor controller.
The CIM motor is the largest we carry, so 50A+ controller (with safety features such as thermal and over-current protection) is necessary. If you have another motor with 300A stall (2000W motor? Yikes!), then you’d need a 75-100A controller.
The CIM should work with that Sabertooth. The wire gauge you see is the maximum diameter.
Yes, the lower the number, the thicker the cable.
You can pretty much use any linear 3-wire 10K potentiometer (5V operation). You don’t need to calibrate or anything. Take a look at the manual and you’ll see which terminal goes to which pin on the potentiometer (you have 5V, Ground and Signal). If the potentiometer does not have wires connected to the terminals which can be screwed into the terminals on the controller, then you may need to solder them yourself (#20 to #24 gauge wire works well).
The one in Fig 2.1 is a simple rotary potentiometer - it’s long because it’s for a knob. There are two sets of three pins, to which they soldered red (to 5V), black (to GND) and yellow (signal) wires. They don’t need both sets, so they left one empty. Most potentiometers have thee pins or connections.
Don’t worry. You need a linear (as opposed to audio) 10K pot which can operate at 5V; the shape, size and connections are secondary.
Not more than any other DC brushed motor.
It should refer to the number of turns needed to go from 0V to full voltage.
Most rotational potentiometers only turn 300 degrees. The resistance along the wiper varies as you turn the knob, creating a difference in voltage. Some applications need a high number of turns, others do not - it’s whatever you want it to be really.
It seems to be a 10 turn, 10K pot, and I hope for ~$20 each that it’s pretty accurate and rugged.
The controllers are setup so so that 2.5V represents neutral, and as you turn it in either direction, the speed slowly increases (opposite directions). You can perhaps physically impede the pot from rotating in reverse, or program a microcontroller to act as intermediary. Honestly - you should purchase any 10k linear pot to test with and see how it goes - a pot should be one of the least expensive parts of the project and most people have a small collection in their workshops.
There are all variations of pots out there (check out Digikey and be overwhelmed). 10 turns seems quite excessive for your application. 300 degrees is normal, and you can certainly find 180 degrees too.
That would likely be the maximum power rating. The pot itself should not consume 1A unless it’s really really large.