This video shows how BigDog starts slipping on ice, almost falls several times, but finally regains its balance and continues walking. BigDog is powered by a gasoline engine that drives a hydraulic actuation system. BigDog's legs are articulated like an animal’s, and have compliant elements that absorb shock and recycle energy from one step to the next. BigDog is the size of a large dog or small mule, measuring 1 meter long, 0.7 meters tall and 75 kg weight.BigDog has the ability to cope with different types of terrains, climb and descend steep slopes, and jump. Two years ago, the older version of BigDog was already able to climb slopes, keep its balance after a strong kick, and walk on rough terrain like stones, mud, and snow. So far, BigDog has trotted at 3.3 mph, climbed a 35 degree slope and carried a 120 lb load.
BigDog has an on-board computer that controls locomotion, servos the legs and handles a wide variety of sensors. BigDog’s control system manages the dynamics of its behavior to keep it balanced, steer, navigate, and regulate energetics as conditions vary. Sensors for locomotion include joint position, joint force, ground contact, ground load, a laser gyroscope, and a stereo vision system. Other sensors focus on the internal state of BigDog, monitoring the hydraulic pressure, oil temperature, engine temperature, rpm, battery charge and others.
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