Stalker

1
Stalker

• Autonomous balancing human finder
• Daniel Wolkenfeld

2
Concept and physical properties
3
Stalker does

• Balances on 2 wheels like the Segway by Dean
  Kamen
• Detects, avoids walls and inanimate objects and
  edge of the world
• Uses heat seeker sensor to find humans and
  follow them while they are moving
• Does not fall over and smash

4
The physics

• Tall is good . . . Stalker gt 1m
• At least 2/3 of mass near the top
• Lightweight wheels and base of chassis for low
  inertia high acceleration
• Requires surprisingly little torque . . .
• 0.1 Nm

5
The math

• Find how much torque is needed to provide an
  acceleration opposite that due to gravity for a
  maximum lean-angle
• ?G ? ?m ? T I ?
• TG mglsin ?
• TM Iw ?w Icm ?cm

6
The gear

• Glowing head fades from green to red as the
  motors vary in output
• 2 Matsushita GMX-6MP009A 24V 1.8Nm 410 rpm with
  encoders
• PVC and aluminum chassis, 12 cm wheels, 4 plastic
  casters, 4kg battery pack
• Infrared sensor, heat seeker, bump sensor, MEMS
  gyro, accelerometer

7
inspired by JOE le Pendule http//leiwww.epfl.ch/
joe/