Building Robots

Radomir Dopieralski

PyZürich 2015

Herbie

• Originally a BEAM light follower
• Based on a simple operational amplifier
• Two analog light sensors
• Two motors
• Battery

Butch

• Random servos
• Meccano set
• 2DoF legs
• Programmable servo controller

Python

• Tethered to PC
• Remote control from PC
  • Bluetooth
  • WiFi
  • ROS?
• PC on board
  • Raspberry Pi
  • VoCore
  • etc.
• MicroPython
  • PyBoard
  • OpenMV
  • WiPy
  • ESP8266
  • Teensy 3.1

Kubik 1

• Raspberry Pi
• Serial Port
• Python
• WiFi

Kubik 2

• LiPo Battery
• 3DoF legs
• UBEC Voltage Regulator
• Speaker
• Joystick

Kubik 3

• Stronger servos
• Ball bearings
• I²C servo controller
• Huge battery

Feed Me Seymour

• unstable → longer legs
• longer legs → bigger servos
• bigger servos → more power
• more power → bigger battery
• bigger battery and servos → greater weight
• greater weight → even bigger servos
• even bigger servos → even more power
• even more power → even bigger battery

RC Servos

• Torque
• PWM
• Current
• Voltage, speed, dead band
• Metal gears, bearings
• Analog/digital

Batteries

• alkaline
• NiMH/NiCD
• LiPo/Li-ion
  • 3.7/4.2V
  • C-rating
  • safety
  • charging
• LiFePO4
• other

Arduino

• Simple
• Cheap
• Popular
• Not Python

µKubik

• Optimal size
• Cheap materials
• Glue versus screws
• Solder versus plugs
• Still programmed in Python!

Inverse Kinematics

• Trigonometry
• Geometry
• Position → Servo angles
• Hours debugging
• Direction and trim
• Vector math?

Nano Kubik

• Two servos per leg for a spider?
• Cheap, cheap, cheap
• Not finished

Partial Inverse Kinematics

• The problem
• Tori on the plane
• Lookup table?

Katka

• Mammal configuration
• Two servos per leg
• Inverse kinematics
• Independent from computer

Walking

• Move body forward
  • Continously
  • Staggered
• Balance body
• Move each feet

Henk

• Micropython
• PyBoard

Leg Construction

• Coxa, femur, tibia
• Hip, knee, ankle

• All weight on the knee
• Twisted ankle
• Dislocated hip
• Range and tangling

µBob

• ESP8266
• Lua

Support Area

• statically/dynamically stable gait
• center of gravity
• area of support

Pico Kubik

• Micropython
• VoCore
• USB Camera
• Printed Circuit Board

Creep Gait

• One leg at a time

1  3

4  2

• Maximizes stability
• Duty cycle

Tote

• Good base platform
• Detailed guide
• Below 30 CHF
• Programmable and extensible
• http://tote.readthedocs.org

Protocols

• Serial (RS232/TTL)
• I²C
• SPI
• 1 Wire
• Analog

Work on Tote

• More code examples
• Different sensors
• Extension boards
• Various leg configurations
• Hackaday Prize https://hackaday.io/project/6050

The Future

• Custom boards
• OpenMV
• More sensors!
• Laser tag
• Beacons

Goji

Logicoma

Resources

• Communities
  • letsmakerobots.com, trossenrobotics.com, hackaday.io
  • #robotics, #arduino, #micropython, #esp8266 @freenode.com
• Software
  • OpenSCAD
  • Fritzing
• Parts
  • Adafruit, Sparkfun, Pololu
  • eBay
• China
  • aliexpress.com
  • dx.com
  • hobbyking.com
  • banggood.com

Thank you!

Questions?

http://sheep.art.pl

https://hackaday.io/deshipu