Brushless Motor H-bridge without R/C inputs for 50V/400W motors?
![Ken Gracey](https://forums.parallax.com/uploads/userpics/937/nHX7GKXF8OR2S.jpg)
Hello,
I am really looking forward to a new project with the Propeller, having worked exclusively on the business side of Parallax for the last six months. We've had a number of staff absent for sabbaticals, personal leave and maternity. So I'm seeking a bit of technical therapy.
The project is a 5-6' long cataraft-looking surface robot designed to study the use of GPS for navigation on a nearby lake. I want to effectively use GPS without too many additional sensor issues to manage at the same time, so the lake is probably the easiest way to do this if I don't want a flying UAV. Managing GPS in the Parallax parking lot is a bit tricky - a robot needs to be large enough to move around a big space, but nice vehicles and UPS trucks pose unique problems. So I'm headed to the water this time.
I have two of Crustcrawler's underwater thrusters:
http://www.crustcrawler.com/products/urov2/index.php
The R/C brushless speed controls for these motors are very expensive ($200). I would rather buy a kit or off-the-shelf product that doesn't support the R/C input signals (1-2 ms pulse every 20-40 ms) but lets me provide the PWM input directly from the Propeller.
Can anybody recommend a reference design, kit, or motor control circuit I might use to design my own? I may use this project as an opportunity to make a PCB.
Any direction would be appreciated, even if you just help me hone the Google search words.
Thanks,
Ken Gracey
I am really looking forward to a new project with the Propeller, having worked exclusively on the business side of Parallax for the last six months. We've had a number of staff absent for sabbaticals, personal leave and maternity. So I'm seeking a bit of technical therapy.
The project is a 5-6' long cataraft-looking surface robot designed to study the use of GPS for navigation on a nearby lake. I want to effectively use GPS without too many additional sensor issues to manage at the same time, so the lake is probably the easiest way to do this if I don't want a flying UAV. Managing GPS in the Parallax parking lot is a bit tricky - a robot needs to be large enough to move around a big space, but nice vehicles and UPS trucks pose unique problems. So I'm headed to the water this time.
I have two of Crustcrawler's underwater thrusters:
http://www.crustcrawler.com/products/urov2/index.php
The R/C brushless speed controls for these motors are very expensive ($200). I would rather buy a kit or off-the-shelf product that doesn't support the R/C input signals (1-2 ms pulse every 20-40 ms) but lets me provide the PWM input directly from the Propeller.
Can anybody recommend a reference design, kit, or motor control circuit I might use to design my own? I may use this project as an opportunity to make a PCB.
Any direction would be appreciated, even if you just help me hone the Google search words.
Thanks,
Ken Gracey
Comments
I can't give any specific links at the moment, but a good Google search to start:
BLDC Sensorless Contollers
Jim
The 120 amp ESC that they specify seems way overkill for a 400 watt motor. I would think that a 40 or 50 amp controller would do just fine. They are about $50 to $60 if you don't need reverse. If you did need reverse you could make it reversible by adding an H bridge to swap two of the motor wires.
Rich H
Jesuit Robotics (parallax sponsors us) used these: http://www.himodel.com/electric/Seaking-60A_Waterproof_Brushless_ESC_for_Boats_W_water-cooling_system.html on our underwater robot last year. The only difficult part with these is that a full reverse signal is required to send them in reverse. for example: to go half speed reverse, you have to send a full seed reverse signal for about a second, then send it the value you want.
Have you looked at any of the controllers made by RoboteQ? It looks like they may have something that would work for your project:
http://www.roboteq.com/
Robert
I'm in the Bay area and need to come to Sac sometime soon. I would be happy to drop by if you would like to chat.
-Rob