As you can see the robot uses two servos on the top of each leg to provide the all important hip joint. This appears to be the key to maintaining balance when walking
Each hip provides rotation in both the horizontal and
the top Hip servo provides the horizontal rotation of the joint the next servo down provides the vertical rotation and has to lift the rest ot the leg and the weight of the knee servo and the foot servo and the support structures. It appears that the upper and middle hip servos are under a lot of load compared to some of the others. The Futaba S3003 servos use plastic gears this would probably be a good place to use a different servo with metal gears
Below the two servo's that act as the hip joint comes another servo to act as the knee this servo provides the kick motion to help lift the foot for walking and kneeling. The servo's appear to be modified by adding a pivot to provide a shaft opposite the motor shaft putting the leg supports in double shear. This is a Very strong and very smart idea.
The knee servo while being rotated vertically by the lower
hip servo also rotates the lower leg servo in the vertical plane.
The linkage from the lower leg servo rotates the foot servo in the vertical plane. It also works in concert with the middle hip servo to provide flexibility when walking or crouching.
The final servo in the leg is operating in the vertical plane and provides one of the functions of the ankle. It's housing also acts as the foot foot the robot
In the chest of this robot is the battery holder it is used to provide support for the battery's and rest of the robot. This is a very efficient use of structure. (Nicely none)
As a demonstration model this robot is excellent. Its shows all of the important joints in as simple of a configuration as possible. Team K.I.S.S for one applauds this kind of thinking. Smart designers/engineers think simple.
Although I cant confirm it (yet) I heard that the servos were hacked by adding a fourth wire to provided feed back to the PIC controller from the potentiometer in the servos. This would make sense to me and would provide a nice pre made feed back sensor for the controller.
Robo1 fights page1
Robo1 fights page2