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Gibbot Board v3 Actuating Board

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ajgriesemer edited this page Oct 4, 2013 · 40 revisions

The Gibbot Board v3 will attempt to fix the issues in the v2 board and add additional functionality. The board will be created with separate modular components so that if a design fails the rest of the board can still be used.

  • Use the layout from the HIP4086 3-phase BLDC Motor Drive Demonstration Board for the MOSFET H-bridge circuit.
  • Use only one current sensor to measure the overall current consumption instead of a sensor to measure the current on each of the three legs of the BLDC motor circuit.
  • 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.
  • A MPU9150 9-Axis IMU.
  • Order 0.033 uF boot strap capacitors instead of stacking two 0.01 uF capacitors.
  • 1A boostrap diodes SL04 40V Reverse Voltage, 10ns reverse recovery time
  • 1A clamping diodes ES1B, 100V reverse voltage, 25ns reverse recovery time
  • Encoder input for magnet encoder JST SH 5 pin
  • Connect the XBee to the dsPIC with CTS and RTS hardware flow control pins.
  • Include logicl 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
  • Include a modular 48V to 24V, 24V to 12V and 12V to 5V buck converter circuit board with redundant inputs in case the buck converter board does not work.
  • 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). This board will have:

Maximum Height = 0.8 inches

Changes

  • GND connection on plug from Power Board to Secondary Board is unconnected
  • IR LED plugs on main board are backwards
  • Holes for MiniFit Jr plugs are too big
  • Power and Ground Planes should be labeled
  • Test points should be labeled
  • Multiple test points are isolated from the planes they should test
  • Caps on 48V to 24V converter are backwards
  • R1 of resistor divider network for 48V to 24V converter should be 21.7V instead of 9.79V
  • More space between boards
  • There is no 24V input plug on the main board, in case the power board needed to be cut off
  • Condense power board based on smaller inverter size
  • Inductor values need to be changed:
    • For 24V circuit a 56uH inductor preforms much better
    • For 12V circuit the datasheet recommends 15uH
    • For 5V circuit the datasheet recommends 6.8uH
    • For 3.3V circuit the datasheet recommends 4.7uH
  • For buck converters, make sure the lower feedback resistor is connected directly to the ground on the switcher (see page 16 of LT1375 datasheet).
  • Use larger sized capacitors
  • Label switch positions
  • Fix GND plane underneath main dsPIC to reduce ground path distance
  • Order 10 uF Tantalum capacitors
  • Mosfet circuits for magnets should be modified so that Mosfet source is connected to ground.
  • Use JST PA connectors instead of JST SH
  • Use caps with a higher voltage rating on the 48V buck converter circuit (at least 60V on the input voltage line).
  • Mount switches and LEDs directly from the side of the board to the shell of the robot
  • Move plugs for magnet control and encoder to top edge of main board
  • Remove redundant lower magnet control and encoder plugs on main board
  • Move IR LED plug to top and bottom edges of board, reduce to one plug if possible and adjust resistor to deliver appropriate current if LEDs are in series (Vf = 1.7V)
  • Motor power should be connected directly to 24V power supply with a switch or jumper wire that can connect it to the unregulated power supply.
  • Adjust 48V to 24V buck converter circuit to accomodate battery input voltage around 28V-34V.
  • Rearrange Encoder output order to match input order on encoder

Current Consumption

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
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