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Optimal design of electric machines, having complex 3-D magnetic flux path, such as transverse flux or axial flux motors, is computationally demanding owing to the unavailability of a fast 2-D finite-element method (FEM), which leads to the indispensable use of costly 3-D FEM models. With multiobjectives and large design parameter vector, this task is further exacerbated. To accelerate the design procedure, unlike conventional methods, this article proposes the use of two information sources, an expensive but accurate high-fidelity 3-D-FEM model and a fast but inaccurate low-fidelity 2-D-equivalent FEM model to exploit corresponding opposite merits of each and construct a multifidelity surrogate model (response surface) with minimum number of expensive 3-D-FEM simulations. The low-fidelity 2-D model, which intrinsically does not exist for such machines, is generated by ensuring equal magnetic reluctance along main magnetic path despite deformation of model's geometry. The proposed methodology is applied to optimize a novel magnetically levitated transverse flux permanent magnet linear synchronous motor, considering suspension characteristics (lateral and normal stiffnesses) along with thrust as objectives and a seven parameter design vector. Results show significant design time-saving without compromising surrogate accuracy. The optimized design is fabricated and relevant experimental measurements are taken. [ABSTRACT FROM AUTHOR]

In this study, a novel 6-degree of freedom compact carrier using magnetically levitated transverse flux permanent magnet linear synchronous motor is proposed and initial design characteristics are analysed. Motor structure is compact with magnetic iron cores for thrust and levitation, arranged orthogonally. This allows reduced magnetic coupling between linear synchronous motor (LSM) and electromagnets despite their close proximity. Such configuration also ensures independent design for propulsion and suspension. Furthermore, by virtue of the proposed configuration, yaw and lateral motion are inherently stable, leaving the required active actuators to merely four for thrust, pitch, roll, and heave active control. Preliminary characteristics are analysed using 3D finite element method and performance considerations for the simultaneous design of LSM and electromagnets are discussed thoroughly. [ABSTRACT FROM AUTHOR]

This paper proposes a new approach for optimal allocation of wireless power transfer system (WPTSys) from a viewpoint of optimal control problem (OCP) for autonomous driving electric vehicles (EVs). These EVs are assumed to accurately follow a pre-determined speed profile. By transformation of the nonlinear optimization problem for optimal allocation of WPTSys to an OCP, well-known methods guaranteeing the global optimality of solution for the OCP are applied, such as Pontryagin’s maximum principle or dynamic programming. Therefore, the global optimal solution of the allocation problem of WPTSys can be obtained. In addition, we consider a practical situation of EV operation from a probability point of view, where many EVs are operated with different initial battery state-of-charge. [ABSTRACT FROM AUTHOR]

SUMMARY Although an electric railway is an ecological transportation system, there are some obstacles when an electric railway is installed: the high cost for installation and the detrimental effect on the environment. A contactless power transfer system (CPT system) is a solid solution for these obstacles. However, a CPT system for a railway application needs to have a high capacity and a tolerance to the misalignment of the coils. In this paper, inductive power transfer theory, which is able to transfer a greater amount of energy than the electromagnetic resonance method is chosen, and its tolerance to the misalignment is our focus. The authors measure various core shapes, and their coupling coefficients, leakage inductances, and excitation inductances according to the misalignment are obtained with a finite element method (FEM) analysis. By using these parameters, the transmitted power and efficiency are calculated by two equivalent circuits: the S/S circuit and the S/P circuit. Finally, by comparing the parameters and transmitted power of each core shape and circuit, the authors show that the circular core can transfer 100 kW of energy for a misalignment of 300 mm. [ABSTRACT FROM AUTHOR]

Utilization of redundancy endows systems with dexterity and fault tolerance in achieving its desired output, but its utilization implies added complication which must be resolved. Input optimization using the two-norm and the infinity-norm are two methods popularly utilized to address this problem. However, each resolution criteria finds its greatest benefit in opposite circumstances. This fact has long motivated a resolution system which makes use of both norms, switching back and forth when called for. In a previous publication, we introduced and proved the continuity of the first realization of such a switching resolution system, implemented in the resolution of biarticular actuation redundancy. In this work, we demonstrate the empirical validity and utility of the switching system through implementation in a developed robotic arm equipped with biarticular actuation redundancy. It is found that resolution allows for equivalent maximum torque requirements as the infinity-norm – an improvement over two-norm – but with improved electrical energy requirements over infinity-norm. [ABSTRACT FROM PUBLISHER]

SUMMARY Electric railway vehicles require high electric power when powering and return high electric output when regenerating. Therefore, the fall in vehicle performance due to a voltage drop and the restriction on regenerative power due to a load shortage become problems in a dc-electrified railway. Therefore, energy storage devices (ESDs) are mounted on vehicles to assist the power of powering operation and to absorb the power of regeneration. In recent years, various hybrid vehicles have been studied because the performance of ESDs has become good enough for them to be mounted on vehicles. Generally, the design of the controller is a complicated problem because the vehicle operates under various running conditions. In this paper, a simple controller for ESDs is designed in the frequency domain. This controller aims at smoothing the input power and at managing the ESD energy. The proposed controller is examined under various running conditions with numerical simulations. [ABSTRACT FROM AUTHOR]

This paper presents a practical design approach of a transverse flux (TF) linear synchronous motor. It is useful in the selection of appropriate volume as a starting point of the thrust requirement design to achieve compact size, small mover weight, high efficiency, and low material cost during the preliminary design stage. First, the concept of the proposed design approach is described. Second, the volume design of a double-sided TF (DSTF) permanent magnet linear synchronous motor (PMLSM) proposed in a previous work is conducted. Finally, based on the experimental results of the prototype model, the feasibility of the proposed design approach is verified by comparing the performance of the DSTF-PMLSM designed using the volume obtained by the proposed design approach with that of the other recent proposals. [ABSTRACT FROM PUBLISHER]

This paper presents an optimal design for achieving high output power in a transverse-flux-type cylindrical linear synchronous generator (TFC-LSM), especially for application in wave power conversion. We obtain optimal design by considering the number of salient poles in armature cores in the designated cross-sectional area. First, we describe the basic configuration of the transverse-flux-type cylindrical model used for design and proceed to explain three types of models with different numbers of salient poles. Second, we describe the optimal design process based on the practical rapid optimal design approach. Finally, we analyze the results of the optimal design of TFC-LSM. [ABSTRACT FROM AUTHOR]

Cogging forces result in thrust ripples and noise, which result in poor positioning accuracy. For that reason, cogging force reduction is one of the most important factors to be considered in the design of permanent magnet linear synchronous motors (PMLSMs) with core type topologies. Many methods have been reported regarding the reduction of the cogging force in PMLSMs. However, since they usually could cause a large decrease of thrust, it is important to select an appropriate method for cogging force reduction by considering a tradeoff relationship between large thrust and small cogging force. This paper presents the design for cogging force reduction of a double-sided transverse flux permanent magnet linear synchronous motor. Several methods including chamfering, skewing, and magnet pole shifting are applied for cogging force reduction. Finally, the design results are analyzed and experimentally validated by the prototype model. [ABSTRACT FROM AUTHOR]

This paper presents the design and analysis of a transverse-flux-type cylindrical linear synchronous motor using generic armature cores for rotary machinery that can address the problem of complex structures in conventional transverse-fluxtype topologies. First, the operational principle and structural advantages of the proposed model are explained. The thrust density and cogging force are investigated during the initial design stage using an application in which large thrust density and low cogging force are required. The proposed model is both theoretically and numerically designed by using a magnetic-circuit method and a 3-D finite-element method, respectively. Finally, the results and efficacy of our structural concept are experimentally validated. [ABSTRACT FROM PUBLISHER]

Biarticular actuators—actuators spanning two joints—play a fundamental role in robot arm designs based on the human musculoskeletal actuation structure. Unlike kinematic redundancy, actuator redundancy resulting from biarticular actuation brings advantages such as increased stability, reduced link inertia, and decreased nonlinearity of the end-effector force with respect to the force direction. The way the actuator redundancy is resolved is a fundamental problem, as it strongly characterizes robot arms performance. In this study, the six most significant actuation redundancy resolution approaches in the literature—1-norm, 2-norm, infinity-norm, phase different control (PDC), nonlinear hase different control (NLPDC), and linear programming (LP)—are analyzed with respect to their design, and experimentally compared with each other using BiWi, a biarticularly actuated and wire-driven robot arm. In addition, an integrated control framework to resolve actuator redundancy maximizing end-effector force and simultaneously minimizing the necessary input torques is proposed. [ABSTRACT FROM PUBLISHER]

Human activity recognition is an important ability in any system that supports human in performing their daily activities. However, current supervised approach in human activity recognition is difficult to be deployed in the natural human living environment where labeled observations are scarce. In this paper, we demonstrate the use of K-means clustering and simple template models to achieve human activity detection and recognition in an unsupervised manner. The features used are extracted from the skeleton data obtained from an inexpensive RGBD (RGB-Depth) sensor. Our results show an average detection performance of 80.4% precision and 83.8% recall. The availability of an unsupervised approach in human activity recognition will make possible the wide adoption of human activity recognition in the natural human living environment. [ABSTRACT FROM AUTHOR]

We propose a double-sided, transverse flux linear synchronous motor to address the problem of the complex structure of transverse-flux machinery. A design method for maximum thrust in a nonsaturation region is then proposed as a simplified approach. Finally, the usefulness of the proposed method are analyzed and evaluated by using a 3-D finite element method. [ABSTRACT FROM AUTHOR]

In this paper, the authors propose short armature core double-sided transverse flux type linear synchronous motor. First, the operational principle and structural advantages of the proposed model are introduced. Focusing on one-core based configuration, a theoretical design of thrust in the designated dimension is then conducted for a simple estimation in the preliminary design stage. Finally, thrust is analyzed and evaluated through field calculations using 3-D finite-element method. [ABSTRACT FROM AUTHOR]