Limits...
Foot placement modification for a biped humanoid robot with narrow feet.

Hashimoto K, Hattori K, Otani T, Lim HO, Takanishi A - ScientificWorldJournal (2014)

Bottom Line: And a foot-landing point is also changed laterally to inhibit the robot from falling to the outside.To reduce a foot-landing impact, a virtual compliance control is applied to the vertical axis and the roll and pitch axes of the foot.Verification of the proposed method is conducted through experiments with a biped humanoid robot WABIAN-2R.

View Article: PubMed Central - PubMed

Affiliation: Waseda Research Institute for Science and Engineering, Waseda University, No. 41-304, 17 Kikui-cho, Shinjuku-ku, Tokyo 162-0044, Japan.

ABSTRACT
This paper describes a walking stabilization control for a biped humanoid robot with narrow feet. Most humanoid robots have larger feet than human beings to maintain their stability during walking. If robot's feet are as narrow as humans, it is difficult to realize a stable walk by using conventional stabilization controls. The proposed control modifies a foot placement according to the robot's attitude angle. If a robot tends to fall down, a foot angle is modified about the roll axis so that a swing foot contacts the ground horizontally. And a foot-landing point is also changed laterally to inhibit the robot from falling to the outside. To reduce a foot-landing impact, a virtual compliance control is applied to the vertical axis and the roll and pitch axes of the foot. Verification of the proposed method is conducted through experiments with a biped humanoid robot WABIAN-2R. WABIAN-2R realized a knee-bended walking with 30 mm breadth feet. Moreover, WABIAN-2R mounted on a human-like foot mechanism mimicking a human's foot arch structure realized a stable walking with the knee-stretched, heel-contact, and toe-off motion.

Show MeSH

Related in: MedlinePlus

Block diagram of the foot placement modification control. Xfpat, Yfpat, and Zfpat are preset foot positions along the x-, y-, and z-axes respectively. θxfpat, θyfpat, and θzfpat are preset foot orientations about the roll, pitch, and yaw axes, respectively. θx is the roll attitude angle, and Fz, Mx, and My are ground reaction forces in the z, roll, and pitch directions.
© Copyright Policy - open-access
Related In: Results  -  Collection


getmorefigures.php?uid=PMC3926377&req=5

fig5: Block diagram of the foot placement modification control. Xfpat, Yfpat, and Zfpat are preset foot positions along the x-, y-, and z-axes respectively. θxfpat, θyfpat, and θzfpat are preset foot orientations about the roll, pitch, and yaw axes, respectively. θx is the roll attitude angle, and Fz, Mx, and My are ground reaction forces in the z, roll, and pitch directions.

Mentions: Figures 3, 4, and 5 depict the outline, timing chart, and block diagram of the proposed control, respectively. This control serves to maintain mechanical energy at the landing, which means that the phase portrait of the proposed system should depict a closed curve. If the mechanical energy diverges, the phase portrait depicts a hyperbolic curve, and a stable walk cannot be maintained.


Foot placement modification for a biped humanoid robot with narrow feet.

Hashimoto K, Hattori K, Otani T, Lim HO, Takanishi A - ScientificWorldJournal (2014)

Block diagram of the foot placement modification control. Xfpat, Yfpat, and Zfpat are preset foot positions along the x-, y-, and z-axes respectively. θxfpat, θyfpat, and θzfpat are preset foot orientations about the roll, pitch, and yaw axes, respectively. θx is the roll attitude angle, and Fz, Mx, and My are ground reaction forces in the z, roll, and pitch directions.
© Copyright Policy - open-access
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC3926377&req=5

fig5: Block diagram of the foot placement modification control. Xfpat, Yfpat, and Zfpat are preset foot positions along the x-, y-, and z-axes respectively. θxfpat, θyfpat, and θzfpat are preset foot orientations about the roll, pitch, and yaw axes, respectively. θx is the roll attitude angle, and Fz, Mx, and My are ground reaction forces in the z, roll, and pitch directions.
Mentions: Figures 3, 4, and 5 depict the outline, timing chart, and block diagram of the proposed control, respectively. This control serves to maintain mechanical energy at the landing, which means that the phase portrait of the proposed system should depict a closed curve. If the mechanical energy diverges, the phase portrait depicts a hyperbolic curve, and a stable walk cannot be maintained.

Bottom Line: And a foot-landing point is also changed laterally to inhibit the robot from falling to the outside.To reduce a foot-landing impact, a virtual compliance control is applied to the vertical axis and the roll and pitch axes of the foot.Verification of the proposed method is conducted through experiments with a biped humanoid robot WABIAN-2R.

View Article: PubMed Central - PubMed

Affiliation: Waseda Research Institute for Science and Engineering, Waseda University, No. 41-304, 17 Kikui-cho, Shinjuku-ku, Tokyo 162-0044, Japan.

ABSTRACT
This paper describes a walking stabilization control for a biped humanoid robot with narrow feet. Most humanoid robots have larger feet than human beings to maintain their stability during walking. If robot's feet are as narrow as humans, it is difficult to realize a stable walk by using conventional stabilization controls. The proposed control modifies a foot placement according to the robot's attitude angle. If a robot tends to fall down, a foot angle is modified about the roll axis so that a swing foot contacts the ground horizontally. And a foot-landing point is also changed laterally to inhibit the robot from falling to the outside. To reduce a foot-landing impact, a virtual compliance control is applied to the vertical axis and the roll and pitch axes of the foot. Verification of the proposed method is conducted through experiments with a biped humanoid robot WABIAN-2R. WABIAN-2R realized a knee-bended walking with 30 mm breadth feet. Moreover, WABIAN-2R mounted on a human-like foot mechanism mimicking a human's foot arch structure realized a stable walking with the knee-stretched, heel-contact, and toe-off motion.

Show MeSH
Related in: MedlinePlus