No abstract

In this paper, we propose new motion schemes for a biped robot to walk up and down a staircase using dynamic encoding algorithm for searches (DEAS) for optimization. Ascending and descending a staircase are scheduled by four phases for convenience of motion generation. Each phase mimics the natural gait of a human being and is easy to analyze and implement. Optimal trajectories of 10 joint motors in a lower extremity of a humanoid are computed to simultaneously satisfy stability conditions, walking constraints, and energy efficiency requirements, and the zero moment point condition. The performance of uDEAS is compared to genetic algorithm in finding 13 parameters with the result that uDEAS requires only 17 seconds, which is 12 times faster. The feasibility of the proposed motion schemes is validated with computer simulations and experiments successfully carried out for a small humanoid robot.

This paper proposes a new trajectory generation scheme for direction turning during biped walking based on our previous study and experiences. For turning in walking, two joints in the sagittal plane should be added in the robot model, and each joint should rotate appropriately considering stability and landing precision. All the angular trajectories for 12 joints in the lower body are approximated by blending polynomials optimized by univariate Dynamic Encoding Algorithm for Searches (uDEAS). The proposed walking scheme is validated via simulation.

No abstract

Phone: þ82 10 4608 1464, Fax: þ82 2 2292 5957 Tungsten-nitrogen-carbide (WN x C y ) thin films were investigated as the metal gate of complementary metal-oxide-semiconductor (CMOS) devices. WN x C y thin films were deposited by employing the remote plasma atomic layer deposition (RPALD) using a bis(tert-butylimido) bis (dimethylamido) tungsten (BTBMW) precursor and hydrogen plasma as a reactant. The growth rate of the WN x C y films was about 0.12 nm/cycle. X-ray diffraction (XRD) analysis indicated that the films consisted of a mixture of tungsten carbide and tungsten nitride phases. The atomic force microscope (AFM) analysis further confirmed that the WN x C y film surfaces deposited by RPALD were smooth. In addition, the chemical bonding state analysis showed that the WN x C y films consisted of WN, WC, and WO phases. To measure the work function of the WN x C y film, a MOSCAP (metal oxide semiconductor capacitor) stack was fabricated and the flat band voltage was measured by current-voltage (C-V) measurements.A WN x C y work function value of 4.91 eV was suitable for p-MOS and the work function of the WN x C y films varied depending on the annealing treatment, and was higher than the work function of the as-deposited WN x C y film.1 Introduction As the feature size of the integrated circuits has continuously decreased, the complementary metal-oxide-semiconductor (CMOS) is affected by several critical properties such as boron penetration from the poly silicon gate to the gate oxide, polycrystalline silicon gate depletion, and high gate resistance, which causes resistance capacitance (RC) interconnection delay [1]. Various metal gate materials such as metals, metal nitrides, metal carbides, and metal silicide are candidates to replace the current use of the poly-Si gate electrode [2]. Among the materials considered for metallic gate electrodes, there are the elemental metal gates but they have several drawbacks. Elemental refractory metals such as Ni, Pt, and Ir for the p-MOS metal gate exhibit poor adhesion to the dielectric layer, are incompatible with the conventional plasma etch processes, and the materials are not cost effective [3]. Another problem with the elemental refractory metal gates is that their work function is difficult to fine-tune. As the