Sunday, February 28, 2021

Pinky buildLog

 Pinky, the octopod AI robot.

Goals: Learn more engineering tricks: Mechanical, Electrical, Software. 

  • Mechanical engineering; Gearing, Servos, Bearings, Nuts, and Bolts.
    • Designed in Fusion 360, then export URDF for ROS.


  • Electrical engineering; Battery (Li-Po), Voltage Converter (5V, 10amp), Microcontroller (pi Pico), Microprocessor (pi Zero W), PWM control board (PCA9685)
  • Software engineering; Windows with Ubuntu VirtualBox (lubuntu20.04), ROS noetic.

Progress videos:

JointControl:
Stand command:x)

In depth details:

  1. knee/hip joints. Drive gear tooth count are: ankle=9t(2x), knee=12t(1.5x), hip=20t(0.9x)
  2. 12ish Volt Li-Po -> voltage converter -> 5-6volts -parallel> 2 PCA9685s v++ terminals
  3. Software
    1. Set up Ubuntu VM
      1. Enable shared clipboard, folder - guest additions
    2. Install ROS on VM 
    3. Configure ROS ENV 

V2 - 2/9/24

Knee and ankle servos have been upgraded to MG996Rs
  • Max Torque @ 4.8V =  9.4 kgf*cm
  • Speed 0.17 s/60 degrees
  • Knee gear ratio: 18:12
  • Ankle Gear ratio: 14:10
  • Ankle torque: 14kgf*cm
  • Knee torque: 15
  • Ankle speed(no load): 257.1 deg/sec 
  • Knee speed(no load): 235.29 deg/sec
 and Hips are:
  • Geared @ 18:9?
  • MG90S(6)
    • Torque 2KG/cm 
  • POWERHD 1810MG(2)