Difference between revisions of "AnkleHardwareSpec2007Sep"

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* ??? board to board stacking connector (more reliable that wires)
 
* ??? board to board stacking connector (more reliable that wires)
  
−
===Ankle Angle Sensor ===
 
−
<strike>
 
−
* 5 pin header with digital signals
 
−
* quadrature encoder (5V single ended) [GND, 5V, ChA, ChB, NDX to dsPIC QEI inputs]
 
−
* or magnetic rotary encoder (such as AS5045 family) [GND, 3.3V, PWM to dsPIC IC timer]
 
−
</strike>
 
  
−
===Strain, SEA, Motor Temp, Supply current, Ankle Ankle===
+
===Strain, SEA, Motor Temp, Supply current ===
−
* 5 analog inputs to CPU, DC to 500 Hz analog bandwidth
+
* 4 analog inputs to CPU, DC to 500 Hz analog bandwidth
 
* 1 x 10k(or more) thermo resistor (requires opamp follower) :  AGND and signal
 
* 1 x 10k(or more) thermo resistor (requires opamp follower) :  AGND and signal
 
* 2 x strain gauge bridges (340 or 1k ohm) to high gain INA326 :  AGND, SG+, SG-, bridge reference
 
* 2 x strain gauge bridges (340 or 1k ohm) to high gain INA326 :  AGND, SG+, SG-, bridge reference
−
* SG bridge reference voltage through 0.1% resistance (1k to reduce bridge current) ideally from AVCC3.3 (ADC reference) or from AVCC5  
+
** SG bridge reference voltage through 0.1% resistance (1k to reduce bridge current) ideally from AVCC3.3 (ADC reference) or from AVCC5  
 
* 1 x analog input for SEA hall sensor board (no voltage or current amp required) : 3.3V, AGND, signal
 
* 1 x analog input for SEA hall sensor board (no voltage or current amp required) : 3.3V, AGND, signal
−
* 1 x analog input for ankle angle (10k-100k) potentiometer (higher bandwidth for fast power cycling)
 
  
−
===Vibrator Motor and Piezo===
+
===Pager Motor===
−
* 4 pin header  
+
* 3 pin header  
 
* ability to turn on/off pager motor (3.3V)   
 
* ability to turn on/off pager motor (3.3V)   
−
* ability to drive miniature piezo (from PWM or OC)
 
  
  
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===Ambient Temperature===
 
===Ambient Temperature===
−
* Thermo resistor (>=10k) with opamp follower placed very close to XY axis IMU
+
* Thermo resistor (>=10k) with opamp follower placed very close to XY axis IMU (or epoxied to XY sensor)
  
 
===Supply Voltage Monitor===
 
===Supply Voltage Monitor===
Line 54: Line 46:
  
 
===IMU===
 
===IMU===
−
* One SPI device, and (upto) 3 analog rate gyro signals
+
* 3 DOF acceleromters, 2 DOF rate
 +
* 3axis (SPI) accelerometer [http://www.sparkfun.com/commerce/product_info.php?products_id=753 LIS3LV02DQ]
 +
** this sensor will be (nearly) always powered and used to wake the processor
  
−
* 3axis (SPI) accelerometer [http://www.sparkfun.com/commerce/product_info.php?products_id=753 LIS3LV02DQ]
+
<strike>
 
* Z axis rate gyro [http://www.sparkfun.com/commerce/product_info.php?products_id=7920 ADXRS300 (analog)] or ADIS16100 (digital)
 
* Z axis rate gyro [http://www.sparkfun.com/commerce/product_info.php?products_id=7920 ADXRS300 (analog)] or ADIS16100 (digital)
 +
</strike>
 
* XY axis (analog) rate gyro [http://www.sparkfun.com/commerce/product_info.php?products_id=700 IDG300]
 
* XY axis (analog) rate gyro [http://www.sparkfun.com/commerce/product_info.php?products_id=700 IDG300]
−
* Note: XY is in circuit board plane, Z axis is normal to circuit board plane
+
** Note: XY is in circuit board plane
  
 
===AVCC5 monitor===
 
===AVCC5 monitor===

Revision as of 21:34, 14 September 2007

State Machine (Master) Controller

  • 25.38V max supply voltage (6 cell LiPoly)
  • IIC EEPROM for controller parameters (24LCxx)


Off board interfaces

Switch Input

  • external logic switch input for mode control

External Serial Communication and ISP

  • Ability to support a variety of attached serial devices: wired RS-232, Bluetooth, 802.11, and ISP.
  • 1Mbaud (max) RS-232 level ASYNC serial (Tx, Rx, RTS, CTS) :
  • Power for external devices: 5V and Vbat (with 0.25amp self resettable fuse)
  • ISP signals (PGC, PGD, MCLR) for external ISP
  • signals: Vbat, Vcc5, GND, Tx, Rx, RTS, CTS, PGC, PGD, MCLR

Power / Data to Motor Controller

  • logic level ASYNC 2-wire serial between SM and motor controller CPUs
  • logic level output to motor controller fault pin to disable PWM
  • logic level input for motor controller alert status
  • (Vbat) battery power from motor controller
  • sense path to battery for voltage monitoring
  •  ??? board to board stacking connector (more reliable that wires)


Strain, SEA, Motor Temp, Supply current

  • 4 analog inputs to CPU, DC to 500 Hz analog bandwidth
  • 1 x 10k(or more) thermo resistor (requires opamp follower) : AGND and signal
  • 2 x strain gauge bridges (340 or 1k ohm) to high gain INA326 : AGND, SG+, SG-, bridge reference
    • SG bridge reference voltage through 0.1% resistance (1k to reduce bridge current) ideally from AVCC3.3 (ADC reference) or from AVCC5
  • 1 x analog input for SEA hall sensor board (no voltage or current amp required) : 3.3V, AGND, signal

Pager Motor

  • 3 pin header
  • ability to turn on/off pager motor (3.3V)


On board sensors

Ambient Temperature

  • Thermo resistor (>=10k) with opamp follower placed very close to XY axis IMU (or epoxied to XY sensor)

Supply Voltage Monitor

  • (better than) 1% accurate measurement of battery voltage (prevent over-voltage during regeneration)

IMU

  • 3 DOF acceleromters, 2 DOF rate
  • 3axis (SPI) accelerometer LIS3LV02DQ
    • this sensor will be (nearly) always powered and used to wake the processor

  • XY axis (analog) rate gyro IDG300
    • Note: XY is in circuit board plane

AVCC5 monitor

  • If SG bridge is powered from AVCC5 then we need to measure AVCC5/2, and SG bridge offsets depend on AVCC5

LEDs

  • 2 LEDs mounted so as to be externally visible


Low Power Support

  • Design for overall low power
  • Target for sleep power of 5mW (0.12WHr/day - from VBAT), processor is sleeping.
  • RS232 output interface disable (Rx still active - SN75C3223)
  • Control of supply to internal sensors : ambient temperature, IMUs
  • Control of supply to external sensors : ankle angle, SG, SEA, motor temperature


Sensor Power

  • EC30 MR-ENC 15.5mA @ 5V : 77.5mW
  • EC30 HALL SEN 10.6mA @ 5V : 53mW
  • SG : 73mW(340ohm/5V), 10mW (1k/3.3V), 2.7mW(1k/1.6V)
  • IDG300 9.5mA @ 3.3V : 31.mW
  • ADXRS300 6-8mA @ 5V : 35mW
  • ADIS16100 7-9mA @ 5V : 40mW
  • ADIS16006 1.5-1.9 @ 3-5V : 5 mW
  • LIS3LV02DQ .6-.8 @ 2.2-3.3V : < 2.6mW
  • ankle angle pot : 0.1-1mW
  • Power supply (LT3470) efficiency 70%>5mA, 60%@1mA, 35%@0.1mA, (0.6mW from Vbat when LT3470 enabled)


software

  • ability to reprogram controller over ASYNC serial
  • 2 DMA controllers run the two ADC units at 12 bits, 400 KHz total sample rate
  • Input capture measures PWM period of magnetic rotary encoder / QEI captures encoder position
  • DMA controller sends/receives SPI to digital accelerometer
  • Main code loop runs at 500 Hz
    • decimation of analog inputs
    • reads ankle position
    • reads IMU, estimates orientation
    • reads motor controller status (motor current, motor position, status)
    • processes external communication interface

Motor Controller

Motor

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