Humanoid robot: A machine that walks

Humanoid robot is a machine which is built to look alike human and to move like a human. That means humanoid robot should satisfy two major aspects: anthropomorphism (looks alike a human) and functionality (moves like a human). The tutorial will present what are the main challenges to achieve these goals and how can we attack the problems by introducing the development outline of Hubo, the first Korean humanoid robot. The full size humanoid robot with height of around 1.5m is quit differ from the toy size small ones in many aspects. It should have very stable and well designed structure with little uncertainties. It must strong enough to move its body weight but not so heavy to minimize the torques to drive the body parts. All the electrical parts and sensors must be compact to be fit in the enclosure of the body. We designed such kind of parts including force/torque sensors, inertia sensors and all the driver circuits, internal decentralized control architecture and hardware. Another important task is design walk algorithm. Walking algorithm is composed with two parts: off-line gait pattern design and real time stabilization control. Gait pattern design is to find a periodic function for each joint of leg such that humanoid robot is to walk with desired velocity keeping certain level of stability. We suggested a simple function connected with cubic spline and sine functions with minimal number of parameters. This approach simplifies the parameter adjustment procedure. Play back of gait pattern found from the former process, however, does not guarantee the robot walks in real practice since there are number of uncertainties involved in real situation. The uncertainties include ground inclination, friction, un-modeled vibration of the body. The stabilization algorithm should deal with such kind of problems. Hubo´s walk algorithm has 8 levels of hierarchical control architecture to cope with the general circumstances in walking environment. The general issues includi- ng mentioned above will be presented at the speech.