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SUMMARY This paper presents a method for electromagnetic torque ripple and copper losses reduction in (non‐sinusoidal or trapezoidal) surface‐mount permanent magnet synchronous machines (SM‐PMSM). The method is based on an extension of classical dq transformation that makes it possible to write a vectorial model for this kind of machine (with a non‐sinusoidal back‐EMF waveform). This model is obtained by the application of that transformation in the classical machine per‐phase model. That transformation can be applied to machines that have any type of back‐EMF waveform, and not only trapezoidal or square‐wave back‐EMF waveforms. Implementation results are shown for an electrical converter, using the proposed vectorial model, feeding a non‐sinusoidal synchronous machine (brushless DC motor). They show that the use of this vectorial mode is a way to achieve improvements in the performance of this kind of machine, considering the electromagnetic torque ripple and copper losses, if compared to a drive system that employs a classical six‐step mode as a converter. Copyright © 2011 John Wiley & Sons, Ltd.

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Research in the area of actuators and mechanisms has shown steadily growing technological advances in externally activated upper limb prostheses. From among the actuators, advances include the use of piezoelectric materials, special metal alloys, polymers, and new motor applications, while the advances in mechanisms include mechanical designs based on the anatomy of the human hand and improvements in the way these components are combined. These efforts are aimed at meeting the need for anthropomorphic and functional prosthetic devices that enable patients to carry out basic daily tasks more easily and reduce the rejection rate of prostheses. This article technically discusses the several types of actuators and mechanisms, listing their main characteristics, applications, and advantages and disadvantages, and the current state of research in the area of rehabilitation of upper limb functions through the use of active prostheses. Comparisons of these devices are made with regard to the main criteria of construction and operation required to achieve optimal prosthetic performance.

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