Revision as of 17:47, 7 September 2007

Motor Controller

• support for Maxon EC30-48V [305015] with 500 CNT MR ENCODER [225778]
  • EC30-48V specs : L=65.3uH, R=386mohm, SpeedConst=346 rpm/volt, TorqueConst=27.6mNm/A
  • Required maximum RPM : 7500

• 25.38V abs max supply voltage
• suggested design using 30V MOSFETs, 35V bulk caps, and 35V DC-DC converter
• Ability to (indefinably) short motor leads when primary power absent or if some sort of system failure
• dsPIC33FJ64MC506 for production, dsPIC33FJ128MC706 used in prototype

• Might be possible to get controller on 1 PCB

Off board interfaces

Motor position sensor

• 5V quadrature with index (single ended or differential)
• 5V hall effect sensor (my require pull up to 5V)

power / data to Motor Controller

• logic level ASYNC 2-wire serial between master and motor controller CPUs
• logic level in to /FLTB (to disable PWM)
• logic level output to indicate alert status
• battery power to motor controller
• low current path to battery for voltage monitoring
•  ??? board to board stacking connector (more reliable that wires)

On board sensors

Motor Current

• Two motor current sensors (ACS712-20)

Battery current monitor

• either ACS712-30 or external loop (offboard)
• battery current monitor needed on this board if a hardware fuse circuit is to be implemented. However, this circuit could be implemented in software on either board.

AVCC5 monitor

• Measure AVCC5/2
• current sensors are radiometric - offsets depend on AVCC5

software

• ability to reprogram controller over ASYNC serial
• SM controller will periodically send ASCII commands to command current and mode
• controller will respond with status (encoder position, actual current)
• absence of valid communication with SM:
  • set current to zero
  • implement virtual spring / damper
  • enable motor lead short sub-circuit

io count

AD

• 2 for motor current
• 1 for 5V (AVCC5/2) supply monitor

• 1 for battery current
• 1 for supply voltage
• 1 or 2 for temperature
• 1 for 5V supply monitor

digital (21 max)

• 6 PWM output
• 2 fault IOs
• 2 ASYNC serial
• 3 for ISP
• 3 for encoder
• 3 for motor hall position sensor
• 2 for LEDs