A new type of shape-memory polymer (SMP) is developed by integrating scientific principles drawn from two disparate fields: the fast-growing photonic crystal and SMP technologies. This new SMP enables room-temperature operation for the entire shape-memory cycle and instantaneous shape recovery triggered by exposure to a variety of organic vapors.
Atomic and close-to-atomic scale manufacturing (ACSM) represents techniques for manufacturing high-end products in various fields, including future-generation computing, communication, energy, and medical devices and materials. In this paper, the theoretical boundary between ACSM and classical manufacturing is identified after a thorough discussion of quantum mechanics and their effects on manufacturing. The physical origins of atomic interactions and energy beams-matter interactions are revealed from the point view of quantum mechanics. The mechanisms that dominate several key ACSM processes are introduced, and a current numerical study on these processes is reviewed. A comparison of current ACSM processes is performed in terms of dominant interactions, representative processes, resolution and modelling methods. Future fundamental research is proposed for establishing new approaches for modelling ACSM, material selection or preparation and control of manufacturing tools and environments. This paper is by no means comprehensive but provides a starting point for further systematic investigation of ACSM fundamentals to support and accelerate its industrial scale implementation in the near future.
Surface-mounted permanent magnet synchronous machine with concentrated windings (cwSPMSM) is a highperformance drive machine and has been adopted in many applications. The difficulty of implementing its sensorless control at low and zero speeds is its multiple saliencies, which is much more significant than most other ac machines. The traditional decoupling methods provide successful results only under the condition that high-order saliencies are not stronger than half of the primary saliency. Furthermore, the behavior of the multiple saliencies is principally frequency dependent. Based on the characteristics of such machines, this paper proposes a multisignal injection method for realizing sensorless control. This method injects multiple highfrequency signals with different frequencies and magnitudes into the machine. Different frequency components in the response current signals are demodulated and then combined together to get the clear primary saliency signal, which is used to identify the rotor position. This new method was validated using a cwSPMSM at low speed. The experimental results proved the effectiveness and accuracy of the new method.Index Terms-Multisignal injection, sensorless control, surfacemounted permanent magnet synchronous machine with concentrated windings (cwSPMSM).
This paper presents an FPGA-based (Field Programmable Gate Array) sensorless controller for Surface Mounted Permanent Magnet Synchronous Machines (SMPMSM). A hybrid sensorless controller combining the signal injection technique and a linearly compensated flux observer is proposed. Using a Delta-Sigma A/D converter and FPGA oversampling technique, this work realizes a high performance high frequency (HF) injection sensorless control method which needs lower HF current response and introduces lower acoustic noises. The linearly compensated flux observer, based on back electromotive force (EMF) is used for sensorless control in the high speed range. The flux observer exhibits high dynamic and steady-state performance and is robust to parameter variation. Using model-based design, with the tools of MATLAB/Simulink and Simulink HDL (hardware description language) Coder, the whole control system is designed and implemented in a single chip. Experimental results demonstrate that the developed sensorless controller has high performance in the whole speed range.Index Terms-Field programmable gate array (FPGA), flux observer, high frequency (HF) injection, model-based design (MBD), sensorless control, synchronous machine (SM).
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