Danny's Mindstorms® Ultimate Biped
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This is an omnidirectional walking biped.

It can walk straight and even turn, using ONLY ONE motor!

The robot is built with Lego Mindstorms RIS 1.5 kit, plus some newer studless parts and a touch  sensor.

 

The motor swings RCX left and right: its weight, that is often a problem in such applications, is used here to shift the Biped's center of gravity.

A gear rack is moved by a 8z gear.

The central touch sensor is used to center weight to its zero position.

There is a touch sensor on each foot, so that the biped always knows which foot is loaded with more weight.It is essential to control walking gaits.

I used a normally close configuration because less force is needed to trigger it (to open): otherwise, if a single touch fails, the robot stops.
Foot sensor detail. Central sensor and rack.  

How can it walk in every direction, using ONLY ONE motor?

It is simple to understand, quite hard to build into Lego.

During these years of continue training, I learned this trick from the master builder ISOGAWA Yoshihito (Yoccha),

that used this mechanism on his chicken-like biped.

Legs are balanced in such a way, that when center of gravity in loads one foot, the other foot is free to move forward.

So, moving weight left and right, biped can walk straight.

I emproved Yoccha's genial idea, changing legs to move parallel to ground: this allows me to make my biped turn (slowly, in wide circles),

simply changing the program timings a bit. To understand better, see videos of Ultimate Biped walking and turning.

Built in October, 2005