Nakamura-Okada Laboratory of the University of Tokyo developed a humanoid robot called Theta. It is used as a platform to address or provide solutions to the theoretical and experimental problems in bipedal walking control based on passive dynamics.
Theta has a double spherical hip joint and a hybrid knee joint that can be changed from passive to an active mode. This gives its developer more opportunity to study the free-swinging dynamics of its leg. Additionally, the Theta has feet similar to that of humans, and its developer made this robot almost human-like in size and weight.
Its developer installed force sensors and a gyroscope making the robot more stable, as it allows the robot to remain in static equilibrium. It can also follow instructions from its operator, i.e. for walking.