Instructions Circuit Diagram

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4. WHO OR WHAT IS YETI?
4.1. Summary
AsdiscussedintherstchaptertheYETIisamythicalgure,
the abominable snowman, living in the Himalya Mountains and clumsily
walking on two big feet.
Our YETI is a tall, upright standing robot, equally walking on two big
feet and being able to move forward or backward or make a left or a
right turn.
Every step forward or backward will start by balancing on one foot and
moving the opposite foot. Basically two servos will be executing these
movements. A servo is a special motor type, including a gear. Gears
are used to reduce speed, but will equally increase the motor’s torque.
Additionally the servo is equipped with impulse-controlled electronics,
allowing an exact positioning of the servo’s rotation angle.
The YETI is equipped with two servomotors, located at the frontside
and at the bottom side. The servo at the frontside rises YETI’s feet in
order to move them (and is named the “feet-servo”) and the servo at
the bottomside moves the legs (including the feet) one by one (the
“legs-servo”).
4.2. The basics of walking
YETI is balancing on one foot and is moving the opposite foot. To do so
YETI pulls the outer side of the “balancing” foot upwards and simulta-
neously presses the outer side of its “moving” foot downwards. These
movements will bend YETI’s body over to the “balancing” foot, which is
now carrying the main part of the robot’s weight. In a next phase YETI
will shift its “moving” foot forward, completing the movement process.
The “moving” foot is now turning into a “balancing” foot and vice versa.
In the walking process these movement are constantly being repeated.