Although many walking control frameworks have been developed to enable biped robots to walk stably on uneven terrain, the foot sole of the robot is also important. Inspired by that study, we have developed a Variable Stiffness Sole (VSS), which is able to adapt to the shape of the obstacles on the ground in Compliant Mode and provide robust support in Stiff Mode. Furthermore, we proposed a walking control framework on uneven terrain for a biped robot equipped with the developed VSS. The proposed walking control framework comprises a posture balance controller to stabilize the zero moment point from disturbances applied to the robot, an ankle torque/foot force controller for walking on uneven terrain, and a VSS controller to change the mode of the VSS. Finally, the proposed framework was verified through walking experiments of RoK-3 equipped with the VSS module on a single obstacle and uneven terrain with various obstacles.

Graffiti work using a humanoid with artistic technique can convey the value of artists' work to people. Previous work that focused on drawing an image on a canvas accurately has not contained artistic processes like performance, drawing skills and other artists' intents at the time of creation. To combine such artistic processes, the work in this paper utilizes whole-body motion of a humanoid to paint an image on a wall using Pointillism. However, a biped humanoid consists of high Degree Of Freedom (DOF) system and is very sensitive to internal and external disturbances from interaction with environments. As is the case when graffitiing on a wall. Most notably, the vibration from impact contacts and mechanical uncertainties limit the humanoid in graffitiing properly. This paper presents an approach to realize drawing a large image on a wall through real-time motion planning for printing, artificial compliance, and a disturbance controller.

This paper discusses balancing for a hopping humanoid biped against various disturbances. Contrary to other studies, the present work focuses on the practical experiment with a real humanoid biped, HUBO2. Also, hopping is focused on among various types of locomotion since hopping is simple movement but more dynamic rather than walking. Two control strategies are proposed according to the magnitude of the disturbances. The one is the posture balance control for small disturbance, which uses the ankle torque of the stance leg. The other is to use the posture balancing control and the landing position control together for large disturbance. The landing position controller changes the landing position of the swing foot to maintain stability. The closed form solution of the landing position controller is addressed with the simplified model. As this simplification, both controllers are used together since the landing position controller cannot maintain a perfect balance alone. To this end, practical experiments with HUBO2 are conducted. In the experiments, HUBO2 maintains a balance against not only small disturbance but also large disturbance such as pushing through the proposed control strategies.

In this paper, we describe the mechanical design, system integration and dynamic walking of the humanoid, KHR-2 (KAIST Humanoid Robot– 2). KHR-2 has 41 DOFs in total, that allows it to imitate various human-like motions. To control all joint axes effectively, the distributed control architecture is used, which reduces computation burden on the main controller, and allows convenient system. A servo motor controller was used as the sub-controller, whereas a 3-axis force/torque sensor and an inertia sensor were used in the sensory system. The main controller attached on the back of KHR-2 communicates with the sub-controllers in real-time through CAN (Controller Area Network) protocol. Windows XP was used as the operation system, whereas RTX HAL extension commercial software was used to realize the real-time control capability in Windows environment. We define the walking pattern and describe several online controllers in each stage. Some of the experimental results of KHR-2 are also presented.