The MARC 1 prototype was used to test some balance software. A small accelerometer was attached to a Stamp PIC. When MARC 1 would tip to one side a servo would move the upper body to rebalance. A simple PID control was used. MARC 1 was the first in a series of prototypes used in developing a biped robot.
This is a companion discussion topic for the original entry at https://community.robotshop.com/robots/show/marc-1