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In the nearly six decades since researchers began to explore methods of creating them, exoskeletons have progressed from the stuff of science fiction to nearly commercialized products. While there are still many challenges associated with exoskeleton development that have yet to be perfected, the advances in the field have been enormous. In this paper, were review the history and discuss the state-of-the-art of lower limb exoskeletons and active orthoses. We provide a design overview of hardware, actuation, sensory, and control systems for most of the devices that have been described in the literature, and end with a discussion of the major advances that have been made and hurdles yet to be overcome. [ABSTRACT FROM AUTHOR]

Several studies have been conducted in order to find the optimal location of actuators and sensors in the active vibration control of structures. In this paper, a modified optimization criterion is proposed for these two optimization problems, ensuring good observability or good controllability of the structure, and considering residual modes to limit the spill-over effects. Its efficiency is shown by the comparison with the classical criteria, illustrated for a simply supported beam and a rectangular plate. In these two applications, the number of active elements is discussed, using or neglecting the residual modes. [ABSTRACT FROM AUTHOR]

Engine adaptation for alternative fueling may generate certain difficulties in terms of configuration or quality of the subassemblies. The main actuator of a modern LPG (Liquefied Petroleum Gas) system is the vapor phase injector. These systems are commonplace because of the possibility of a modification of the mixture composition in order to meet the emission standards. Multitude of injector design solutions and quality of their workmanship frequently make them the main reason for system malfunction, hence, the need to apply simplified research methods in the course of operation that would allow an assessment of their technical condition. The paper directly compares selected research procedures evaluating their applicability. The proposed method of pressure measurement at the outlet of the injector nozzle turned out to be sufficient for a non-invasive assessment of the technical condition of the injector, which was confirmed by the measurement of the injector piston lift by the displacement sensor. The current on the power line and the vibrations of the injector housing have been sufficient to diagnose the subassembly, thus supporting the decision on the extent of the repair. [ABSTRACT FROM AUTHOR]