Mastersailor
USA
Asked
— Edited
Resolved by kamaroman68!
Greetings,
Attempting to take the DIY supplied small voltage servos and run large voltage 1000 watt electric motors (2). I think it can be done with hardware and apologize in advance for my need to be enlightened. Should I be using a more industrial platform?
Warmly,
Greg
At the heart of ALL robotics, big or small are little tiny fragile CPU's... just like the ez-b v4
However, the structure you build around it - no matter how HUGE is irrelevant.
Your question is how to control large 1000 watt motors. The answer is easy... with an HBridge.
Every motor connected to ANY cpu MUST be connected with some form of switching capability.... because a CPU cannot power a motor directly (obviously).
The answer is use an HBridge. Everything that has a motor has an HBridge... including servos or anything. That's what an HBridge does.
The answer lies on what HBridge you wish to use. There's many out there - and most people swear by SaberTooth (as do I). I would suggest buying a sabertooth hbridge and controlling it with EZ-B v4 in ARC using either of these HBridge controls
- native 4 wire + pwm hbridge: https://www.ez-robot.com/Tutorials/Help.aspx?id=192
- sabertooth serial (1 wire): https://www.ez-robot.com/Tutorials/Help.aspx?id=173
You decide what control - and you decide what hbridge
You would need a super high current 48V supply (or maybe 4 car batteries in series) for your motors obviously but yes you could control that voltage going to your motors with a Relay (solid state or otherwise) interfaced to an EZ-B.
Do you need the motors to turn bidirectionally or just one direction? If you need bidirectional movement you will need a pretty heavy duty H-Bridge, one of which I'm not too sure even exists. I'm not sure if Wheel chair motor H-bridges could work but you could always use 4 relays per motor in an H-bridge configuration as well.
P = V*I (Power = Voltage x Current)
1000W = 48V * I
I = 1000W/48V = 20.8A
I guess that amount of current isn't too out of reach, @DJ is right a Sabertooth 2x25 or 2x32 could probably handle the motors.
* Whoops I just noticed that the Sabertooths max out at 30V
I am using deep cycle gel 12 V batteries. If I understand the technology I should get
10 years of heavy use out of them. I have a remote charging system which I have to fabricate, that I think will work to charge them in series. Thank you for keeping me on the straight and narrow. If I understand encoders, I don't think I need them.
I will need to keep this as simple as possible.
Thank you for your help.
Greg
Yes motors will need to be bi directional.
Trying Super Droid
I think this will work?
Sabertooth seems to burn up at 27v