Motor
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Contents
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
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