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Article
Publication date: 1 February 1995

T. NAKATA, N. TAKAHASHI and K. FUJIWARA

Seven computer codes developed by five groups are applied to the benchmark problem 13 of the TEAM Workshop which consists of steel plates around a coil (a nonlinear magnetostatic…

137

Abstract

Seven computer codes developed by five groups are applied to the benchmark problem 13 of the TEAM Workshop which consists of steel plates around a coil (a nonlinear magnetostatic problem). The solutions are compared with each other and with experimental results.

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COMPEL - The international journal for computation and mathematics in electrical and electronic engineering, vol. 14 no. 2/3
Type: Research Article
ISSN: 0332-1649

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Book part
Publication date: 1 October 2008

Kenji Fujiwara, Nobuhito Suga and Makoto Tawada

Purpose – This chapter aims to examine trade patterns and gains from trade in a two-country general equilibrium model of increasing returns and oligopoly.Approach – A general…

Abstract

Purpose – This chapter aims to examine trade patterns and gains from trade in a two-country general equilibrium model of increasing returns and oligopoly.

Approach – A general equilibrium model of increasing returns and oligopoly.

Findings – The determination of patterns of specialization and trade and gains from trade highly depends on the interaction between the degree of increasing returns and market power as well as the cross-country difference in factor endowments.

Originality – Unlike the existing literature, we endogenize the determination of specialization by using an allocation curve approach by Ethier (1982). To our knowledge, there is no comparable study that incorporates Ethier's (1982) approach to oligopolistic models of international trade.

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Globalization and Emerging Issues in Trade Theory and Policy
Type: Book
ISBN: 978-1-84663-963-0

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Article
Publication date: 1 January 1988

Nathan IDA

Problem 2 of the International Workshop for Eddy Current Code Comparison is a hollow cylinder with its axis perpendicular to a uniform sinuosoidal field. A total of 10 solutions…

59

Abstract

Problem 2 of the International Workshop for Eddy Current Code Comparison is a hollow cylinder with its axis perpendicular to a uniform sinuosoidal field. A total of 10 solutions, employing 9 different computer codes, are described and compared with analytic results. Most codes were 2‐D finite element and were found to give satisfactory solutions.

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COMPEL - The international journal for computation and mathematics in electrical and electronic engineering, vol. 7 no. 1/2
Type: Research Article
ISSN: 0332-1649

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Article
Publication date: 1 March 1992

Takayoshi NAKATA and Koji FUJIWARA

Benchmark problem 13 of the TEAM Workshop consists of steel plates around a coil (a nonlinear magnetostatic problem). Seventeen computer codes developed by twelve groups are…

184

Abstract

Benchmark problem 13 of the TEAM Workshop consists of steel plates around a coil (a nonlinear magnetostatic problem). Seventeen computer codes developed by twelve groups are applied, and twenty‐five solutions are compared with each other and with experimental results. In addition to the numerical calculations, two theoretical presentations are given in order to explain discrepancies between the calculations and the experiment.

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COMPEL - The international journal for computation and mathematics in electrical and electronic engineering, vol. 11 no. 3
Type: Research Article
ISSN: 0332-1649

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Article
Publication date: 1 March 1990

Koji FUJIWARA and Takayoshi NAKATA

Benchmark problem 7 of the TEAM workshop consists of an asymmetrical conductor with a hole. 17 computer codes are applied, and 25 solutions are compared with each other and with…

454

Abstract

Benchmark problem 7 of the TEAM workshop consists of an asymmetrical conductor with a hole. 17 computer codes are applied, and 25 solutions are compared with each other and with experimental results for eddy current densities and flux densities. Most of the codes were found to give satisfactory solutions.

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COMPEL - The international journal for computation and mathematics in electrical and electronic engineering, vol. 9 no. 3
Type: Research Article
ISSN: 0332-1649

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Article
Publication date: 1 March 1990

Takayoshi NAKATA and Koji FUJIWARA

Benchmark problem 10 of the TEAM workshop consists of steel plates around a coil (non‐linear transient eddy current problem). Six computer codes are applied, and 6 solutions are…

111

Abstract

Benchmark problem 10 of the TEAM workshop consists of steel plates around a coil (non‐linear transient eddy current problem). Six computer codes are applied, and 6 solutions are compared with each other and experimental results for eddy current densities as well as flux densities. Some codes were found to give oscillatory solutions.

Details

COMPEL - The international journal for computation and mathematics in electrical and electronic engineering, vol. 9 no. 3
Type: Research Article
ISSN: 0332-1649

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Article
Publication date: 21 March 2016

Fayong Guo, Tao Mei, Minzhou Luo, Marco Ceccarelli, Ziyi Zhao, Tao Li and Jianghai Zhao

Humanoid robots should have the ability of walking in complex environment and overcoming large obstacles in rescue mission. Previous research mainly discusses the problem of…

282

Abstract

Purpose

Humanoid robots should have the ability of walking in complex environment and overcoming large obstacles in rescue mission. Previous research mainly discusses the problem of humanoid robots stepping over or on/off one obstacle statically or dynamically. As an extreme case, this paper aims to demonstrate how the robots can step over two large obstacles continuously.

Design/methodology/approach

The robot model uses linear inverted pendulum (LIP) model. The motion planning procedure includes feasibility analysis with constraints, footprints planning, legs trajectory planning with collision-free constraint, foot trajectory adapter and upper body motion planning.

Findings

The motion planning with the motion constraints is a key problem, which can be considered as global optimization issue with collision-free constraint, kinematic limits and balance constraint. With the given obstacles, the robot first needs to determine whether it can achieve stepping over, if feasible, and then the robot gets the motion trajectory for the legs, waist and upper body using consecutive obstacles stepping over planning algorithm which is presented in this paper.

Originality/value

The consecutive stepping over problem is proposed in this paper. First, the paper defines two consecutive stepping over conditions, sparse stepping over (SSO) and tight stepping over (TSO). Then, a novel feasibility analysis method with condition (SSO/TSO) decision criterion is proposed for consecutive obstacles stepping over. The feasibility analysis method’s output is walking parameters with obstacles’ information. Furthermore, a modified legs trajectory planning method with center of mass trajectory compensation using upper body motion is proposed. Finally, simulations and experiments for SSO and TSO are carried out by using the XT-I humanoid robot platform with the aim to verify the validity and feasibility of the novel methods proposed in this paper.

Details

Industrial Robot: An International Journal, vol. 43 no. 2
Type: Research Article
ISSN: 0143-991X

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Article
Publication date: 16 May 2016

Fayong Guo, Tao Mei, Marco Ceccarelli, Ziyi Zhao, Tao Li and Jianghai Zhao

Walking on inclined ground is an important ability for humanoid robots. In general, conventional strategies for walking on slopes lack technical analysis in, first, the waist…

264

Abstract

Purpose

Walking on inclined ground is an important ability for humanoid robots. In general, conventional strategies for walking on slopes lack technical analysis in, first, the waist posture with respect to actual robot and, second, the landing impact, which weakens the walking stability. The purpose of this paper is to propose a generic method for walking pattern generation considering these issues with the aim of enabling humanoid robot to walk dynamically on a slope.

Design/methodology/approach

First, a virtual ground method (VGM) is proposed to give a continuous and intuitive zero-moment point (ZMP) on slopes. Then, the dynamic motion equations are derived based on 2D and 3D models, respectively, by using VGM. Furthermore, the waist posture with respect to the actual robot is analyzed. Finally, a reformative linear inverted pendulum (LIP) named the asymmetric linear inverted pendulum (ALIP) is proposed to achieve stable and dynamical walking in any direction on a slope with lower landing impact.

Findings

Simulations and experiments are carried out using the DRC-XT humanoid robot platform with the aim of verifying the validity and feasibility of these new methods. ALIP with consideration of waist posture is practical in extending the ability of walking on slopes for humanoid robots.

Originality/value

A generic method called ALIP for humanoid robots walking on slopes is proposed. ALIP is based on LIP and several changes, including model analysis, motion equations and ZMP functions, are discussed.

Details

Industrial Robot: An International Journal, vol. 43 no. 3
Type: Research Article
ISSN: 0143-991X

Keywords

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Book part
Publication date: 2 June 2008

Sajal Lahiri and Yoshiyasu Ono

We develop a 2×2×2 model of international trade in which one of the sectors is oligopolistic. The oligopolistic sector consists of a given number of a priori identical firms…

Abstract

We develop a 2×2×2 model of international trade in which one of the sectors is oligopolistic. The oligopolistic sector consists of a given number of a priori identical firms belonging to one of the two countries, but some deciding to locate in the other country so as to realize higher profits. If a firm locates in the foreign country, its technological capability is assumed to go down due to the alien environment. In this framework we examine the effect of the environment on the level of foreign direct investment and on factor prices in the two countries.

Details

Contemporary and Emerging Issues in Trade Theory and Policy
Type: Book
ISBN: 978-1-84950-541-3

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Article
Publication date: 7 August 2019

Ryoko Minehisa, Yasuhito Takahashi, Koji Fujiwara, Norio Takahashi, Masafumi Fujita, Kazuma Tsujikawa and Ken Nagakura

This paper aims to propose a homogenization method considering magnetic anisotropy for a magnetic field analysis of a turbine generator. To verify the validity of the proposed…

77

Abstract

Purpose

This paper aims to propose a homogenization method considering magnetic anisotropy for a magnetic field analysis of a turbine generator. To verify the validity of the proposed method, the effects of magnetic anisotropy and a space factor on a no-load saturation curve and no-load iron loss of the turbine generator are discussed.

Design/methodology/approach

The proposed method was derived from the combination of the homogenization of microscopic fields in a laminated iron core with the modelling of two-dimensional magnetic properties based on free energy. To verify the validity, the proposed method was applied to a finite-element analysis of a simple ring core model. Finally, a no-load saturation curve and iron loss of the turbine generator was investigated by using the proposed method.

Findings

The computational accuracy of the homogenization method considering magnetic anisotropy is almost the same as that of the detailed modelling of the laminated structure in the magnetic field analysis of the laminated iron core. Furthermore, it is clarified that magnetic anisotropy does not have a large influence on the no-load saturation curve of the turbine generator because of the large air gap. On the other hand, the space factor affects the shape of the no-load saturation curve.

Originality/value

This paper verifies the validity of the homogenization method considering magnetic anisotropy method and elucidates the effects of magnetic anisotropy and a space factor on no-load characteristics of the turbine generator.

Details

COMPEL - The international journal for computation and mathematics in electrical and electronic engineering , vol. 38 no. 5
Type: Research Article
ISSN: 0332-1649

Keywords

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