RC08Brushless

In 2008 RoboCup switched to brushless DC motors. While brushless motors are smaller and far more efficient than brushed motors the commutation normally performed inside a brushed DC motor will need to be done externally using some control circuitry. There are two main parts to our brushless motor controller solution; the controller which uses sensors on the motor to gate signals to one of three coils, and the half-bridge motor drivers which actually drive the coils. There are two design paths: one with a special purpose controller, and one with a CPLD as the controller. On this page you will find information about both. For information on the motors or motor control software please see their respective pages.

Task

• [ ] Get the motor and begin playing with it
  • [ ] Call Maxon and get a recommendation on motor drivers
  • [ ] Figure out max current draw. (Please be below 3A!!)
• [ ] Finalize on a DSC
• [ ] Choose MOSFETS
• [ ] Sample all the parts
• [ ] Set-up test-circuit
• [ ] Prototype Circuit
• [ ] Build prototype

Specifications

Motor Controller Chip

• The motor is spec'd at 12V and is 30W so that means we drawn 833mA per channel
• A decent transient response (This will be a function of hardware and software)
• 3-Channels in one package
• Braking is not a requirement but would be nice (We could just as easily do it software)
• High Impedance OFF state
• Ability to operate in the >20kHz range
• Gate drive capability (either can directly driver the gate or is open drain.)
• Data sheet recommends a MOSFET

MOSFET

• Depletion Mode
• Probably an NMOS and a PMOS
• I want to say 10A as the data sheet for the motor gives a 10A starting current but I need to check with someone

Schematics

Schematics

Parts

DSC

I've posted all the an excel file of controllers I've seen on the collab site.

Links

• Electrical System