Difference between revisions of "Motor"
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=Motor Controller= | =Motor Controller= | ||
| − | * support for Maxon EC30-48V [305015] with 500 CNT MR ENCODER [225778] | + | * primary 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 | ** EC30-48V specs : L=65.3uH, R=386mohm, SpeedConst=346 rpm/volt, TorqueConst=27.6mNm/A | ||
** Required maximum RPM : 7500 | ** Required maximum RPM : 7500 | ||
* 25.38V abs max supply voltage (6 cell LiPoly) | * 25.38V abs max supply voltage (6 cell LiPoly) | ||
| − | |||
* support for 50KHz to 100 KHz PWM | * support for 50KHz to 100 KHz PWM | ||
* suggested design using 30V MOSFETs, 35V bulk ceramic caps, and 35V input DC-DC converter | * suggested design using 30V MOSFETs, 35V bulk ceramic caps, and 35V input DC-DC converter | ||
* Ability to (indefinably) short motor leads when primary power absent or if some sort of system failure | * Ability to (indefinably) short motor leads when primary power absent or if some sort of system failure | ||
*suggest dsPIC33FJ64MC506 for production, dsPIC33FJ128MC706 used in prototype | *suggest dsPIC33FJ64MC506 for production, dsPIC33FJ128MC706 used in prototype | ||
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* Might be possible to get controller on 1 PCB | * Might be possible to get controller on 1 PCB | ||
| − | |||
* IIC EEPROM for controller parameters | * IIC EEPROM for controller parameters | ||
| + | * Ultra short and wide high current paths. | ||
==Off board interfaces== | ==Off board interfaces== | ||
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* Motor wires (3x18AWG) solder directly to holes adjacent to current sensor / MOSFET outputs | * Motor wires (3x18AWG) solder directly to holes adjacent to current sensor / MOSFET outputs | ||
| − | + | === Motor position sensors=== | |
| − | === Motor position | + | * 5V quadrature with index (single ended or differential ???) |
| − | * 5V quadrature with index (single ended or differential) | + | * 5V hall effect sensor (may require 10k pull up to 5V) |
| − | * 5V hall effect sensor ( | ||
=== power / data to Motor Controller === | === power / data to Motor Controller === | ||
| Line 33: | Line 30: | ||
* logic level output to indicate alert status | * logic level output to indicate alert status | ||
* battery power to motor controller | * battery power to motor controller | ||
| − | * | + | * sense path to battery for voltage monitoring |
| − | * | + | * board to board stacking connector (more reliable that wires) |
==On board sensors== | ==On board sensors== | ||
| + | * NOTE: Motor temp and battery voltage sensor moved to SM | ||
| + | * Battery current sensor kept local to facilitate electronic fuse. | ||
| + | |||
===Motor Current=== | ===Motor Current=== | ||
| − | * Two motor current sensors (ACS712-20) | + | * Two motor current sensors (ACS712-20) (+-25amps peak) |
| + | * ??? First order LP filter at >= 20 KHz | ||
| + | |||
===Battery current monitor=== | ===Battery current monitor=== | ||
| − | *either ACS712-30 or external loop (offboard) | + | * 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. | * 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=== | ===AVCC5 monitor=== | ||
* Measure AVCC5/2 | * Measure AVCC5/2 | ||
| − | * current sensors are | + | * current sensors are ratiometric - offsets depend on AVCC5 |
| + | |||
| + | ==Low Power Support== | ||
| + | * Design for overall low power | ||
| + | * Target for sleep power of 5W (0.12WHr/day - from VBAT), (processor is sleeping @ 200uA) | ||
| + | * Control of supply to internal sensors : ACS712, battery monitor | ||
| + | * Control of supply to external sensors : motor encoder, motor hall sensors | ||
| + | * Control of supply to mosfet drivers. | ||
| + | |||
==software== | ==software== | ||
* ability to reprogram controller over ASYNC serial | * ability to reprogram controller over ASYNC serial | ||
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** implement virtual spring / damper | ** implement virtual spring / damper | ||
** enable motor lead short sub-circuit | ** enable motor lead short sub-circuit | ||
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Revision as of 21:48, 9 September 2007
Contents
Motor Controller
- primary 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 (6 cell LiPoly)
- support for 50KHz to 100 KHz PWM
- suggested design using 30V MOSFETs, 35V bulk ceramic caps, and 35V input DC-DC converter
- Ability to (indefinably) short motor leads when primary power absent or if some sort of system failure
- suggest dsPIC33FJ64MC506 for production, dsPIC33FJ128MC706 used in prototype
- Might be possible to get controller on 1 PCB
- IIC EEPROM for controller parameters
- Ultra short and wide high current paths.
Off board interfaces
SUPPLY POWER
- Wires (2x16 AWG, 1x22AWG) to enclose connector solder directly to holes adjacent to bulk bypass caps
- 3rd wire used to implement electronic delayed electronic (soft start) switch
MOTOR POWER
- Motor wires (3x18AWG) solder directly to holes adjacent to current sensor / MOSFET outputs
Motor position sensors
- 5V quadrature with index (single ended or differential ???)
- 5V hall effect sensor (may require 10k 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
- sense path to battery for voltage monitoring
- board to board stacking connector (more reliable that wires)
On board sensors
- NOTE: Motor temp and battery voltage sensor moved to SM
- Battery current sensor kept local to facilitate electronic fuse.
Motor Current
- Two motor current sensors (ACS712-20) (+-25amps peak)
- ??? First order LP filter at >= 20 KHz
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 ratiometric - offsets depend on AVCC5
Low Power Support
- Design for overall low power
- Target for sleep power of 5W (0.12WHr/day - from VBAT), (processor is sleeping @ 200uA)
- Control of supply to internal sensors : ACS712, battery monitor
- Control of supply to external sensors : motor encoder, motor hall sensors
- Control of supply to mosfet drivers.
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
