HUBO

HUBO is a humanoid robot developed at the Korea Advanced Institute of Science and Technology. The first HUBO, KHR-3, was the culmination of four years of research based on three earlier prototypes, KHR-0, 1, and 2, and it was officially unveiled to the public on January 6, 2005. KHR-3 is physically similar to Honda's ASIMO, weighing 56 kg and standing at a height of 125 cm. Albert HUBO is the second and latest HUBO. It features an artificial head of Albert Einstein in place of the previous design resembling a CRT monitor. The name HUBO is short for humanoid robot.

Development history
The first HUBO was developed by mechanical engineering professor Oh Junho and his Ph.D. student teams over the course of about 20 years. During much of this time, the HUBO was steadily developed, and involvement of amateurs resulted in a very low development cost of about $500,000. (In comparison, Honda had spent $300 million on its ASIMO at the time of the KHR-3's completion.)

The first prototype was the KHR-0 (KAIST Humanoid Robot), which essentially consisted of two legs without an upper body. It was built in 2001 for the purpose of investigating the specifications of actuators (devices that receive electric signals and perform mechanical actions), such as power, torque, and speed, and the optimal weight and size of a humanoid robot.

The second prototype, the KHR-1, was completed by January 2002. The KHR-1 was a bipedal humanoid with a headless torso and two hand-less arms, and its purpose was to demonstrate autonomous walking that involves real-time motion control through sensory feedback. (This involves constant adjustments that are absent in walking as a playback motion adopted from an offline learning process and walking with partial online adjustments.) It could make right turns and walked at 0.8km/hr.

The project was continued with the development of KHR-2 from 2003 to 2004. The KHR-2 was built as a complete humanoid and featured better sensoring with the addition of CCD cameras, inertia sensors, and tilt sensors. It was used as a platform for simulation of vision-guided dynamic walking, in which the robot keeps focus on a moving red light for direction.

Design and engineering principles
For practical and efficient engineering, the robot was built at a child's height of 119 cm.

In order to simulate autonomous walking, the KHR-1 was built without external connections, and it was controlled wirelessly and operated on internal batteries with low-level consumption. All models were built with harmonic drives in order to avoid backlash in the gears and to achieve a light, compact design. The DOFs of the different axes in the joints of shoulders, waist, hips, and ankles were merged into intersections in order to attain a simple, closed-form solution (that is, comprised of well-known mathematical functions) of inverse kinematics (the computation of the robot's movements). The KHR-1's walking movement was based on the Zero Moment Point trajectory (points of contact on the ground where the total moment of inertia of the active forces equals to 0) predicted based on a simple model of the robot.