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Gibbot Board v3 Actuating Board

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ajgriesemer edited this page Oct 28, 2013 · 40 revisions

The Gibbot Board v3 will attempt to fix the issues in the v2 board and add additional functionality. The board will test the design of a few unverified systems. These systems include: buck converters, XBee, magnet control, encoders, I2C Communication. To prevent the board from being useless the board with be created with modular designs so that the rest of the board can be used if an untested design fails. The characteristics of the board are:

  • Include a modular 48V to 24V, 24V to 12V and 12V to 5V buck converter circuit board with redundant inputs. If the buck converter does not work the module can be cut and the rest of the board powered by an external power supply.
  • Include a separate modular board for the second arm of the robot. This board will have only 4 inputs to minimize the number of wires through the link, these are: 24V, GND, SDA and SCLK (or possibly RX and TX). The components on this board will include:
  • Reduce the size of the motor driver by using the layout from the HIP4086 3-phase BLDC Motor Drive Demonstration Board for the MOSFET H-bridge circuit.
  • Reduce the number of current sensors from three to one by measuring the overall current consumption across all 3 motor driver leads instead of a sensor to measure the current on each of the three leads.
    • Use the X6BB (100mV/A sensing) version of the ACS716 Current Sensors instead of the X12CB (37 mV/A sensing) for more precise measurement.
  • Use the dsPIC33EP512MC806 for more pins and functionality.
  • Include a 0.1uF decoupling capacitor between each of the 3.3V and GND pins on the dsPIC as well as a 10uF ceramic through hole decoupling capacitor on at least one pair of pins.
  • Add a MPU9150 9-Axis IMU.
  • Modify the following components to meet current load specs:
    • 1A boostrap diodes SL04 40V Reverse Voltage, 10ns reverse recovery time
    • 1A clamping diodes ES1B, 100V reverse voltage, 25ns reverse recovery time
  • Add encoder inputs for magnet encoder JST SH 5 pin
  • Improve the connection from the XBee to the dsPIC with hardware flow control pins (CTS and RTS).
  • Include logic level MOSFETs for driving both magnets SSM3K329R,LF.
  • Include holes for 4-40 stand off screws.
  • Status LEDS
  • On/Off Switch
  • 6 IR LED outputs
  • User Button
  • Reset Button
  • Plug in connectors instead of Screw Terminals

Maximum Height = 0.8 inches

Current Consumption

The maximum current consumption required from the buck converters is calculated in the tables below.

5V

Component Current per unit Total Component Value Source
dsPIC 320mA dsPIC33EP512MC806 datasheet, absolute maximum rating current from VSS
Status LEDs 3.3mA x 6 20mA Assuming 3.3V and 1k resistor
Motor Hall Effect Sensors 5mA x 3 15mA Assuming 5V and 1k resistor, worst case all three on
3 Encoders 78mA x 3 234mA E3 1600 CPR product page 62mA maximum no load current + 8mA x 2 maximum output current
IMU 10mA MPU-9150 datasheet 3.9mA gyro + 6mA magnetometer
XBee 95mA Series 1 XBee Datasheet 45mA transmit current + 50mA recieve current
IR LEDs 10mA x 6 60 mA 3.3V and 330 ohm resistor
Total 754mA

12V

Component Current per unit Total Component Value Source
HIP4086 40mA 11mA VDD operating current + 2mA x 3 xHB + 2mA x 3 Bootstrap current (Experimental value < 40mA)

24V

Component Current per unit Total Component Value Source
Magnets 230mA x 2 460mA APW Magnets datasheet
24V to 12V Converter 40mA / 40% 100mA From above
24V to 5V Converter 754 / 82% 919mA
Total 1.479 A

Secondary Board

5V

Component Current per unit Total Component Value Source
2 Encoders 78mA x 2 156mA E3 1600 CPR product page 62mA maximum no load current + 8mA x 2 maximum output current

3.3V

Component Current per unit Total Component Value Source
dsPIC 320mA dsPIC33EP512MC806 datasheet, absolute maximum rating current from VSS
Status LEDs 3.3mA x 6 20mA Assuming 3.3V and 1k resistor
IMU 10mA MPU-9150 datasheet 3.9mA gyro + 6mA magnetometer
IR LEDs 10mA x 6 60 mA 3.3V and 330 ohm resistor
Total 0.410 A
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