This paper presents the design, dynamic modeling and motion control of a novel cable-driven upper limb robotic exoskeleton for a rehabilitation exercising. The proposed four degree-of-freedom robotic exoskeleton, actuated by pneumatic artificial muscle actuators, is characterized by a safe, compact, and lightweight structure, complying with the motion of an upper limb as close as possible. In order to perform a passive rehabilitation exercise, the dynamic models were developed by the Lagrange formulation in terms of quasi coordinates combined with the virtual work principle, and then the adaptive fuzzy sliding mode control was designed for the rehabilitation trajectory control. Finally, rehabilitation experiments were conducted to validate the prototype of upper limb robotic exoskeleton and the controller design. INDEX TERMS Pneumatic artificial muscle, robotic exoskeleton, rehabilitation, adaptive fuzzy sliding mode control.
This work determines the effect of compact TiO2layers that are deposited onto fluorine-doped tin oxide (FTO), to improve the performance of dye-sensitized solar cells (DSSC). A series of compact TiO2layers are prepared using radio frequency (rf) reactive magnetron sputtering. The films are characterized using X-ray diffraction (XRD), atomic force microscopy (AFM), scanning electron microscopy (SEM), and UV-Vis spectroscopy. The results show that when the Ar/O2/N2flow rates are 36 : 18 : 9, the photo-induced decomposition of methylene blue and photo-induced hydrophilicity are enhanced. After annealing at 450°C in an atmosphere ambient for 30 min, the compact TiO2layers exhibit higher optical transmittance. The XRD patterns for the TiO2films for FTO/glass show a good crystalline structure and anatase (101) diffraction peaks, which demonstrate a higher crystallinity than the ITO/glass films. As a result of this increase in the short circuit photocurrent density, the open-circuit photovoltage, and the fill factor, the DSSC with the FTO/glass and Pt counter electrode demonstrates a solar conversion efficiency of 7.65%.
This paper examines optimal settings for deposition parameters for transition metal nitride (ZrN, WN and ZrWN) thin films that are deposited on tungsten carbide tools and glass substrates using direct current (DC) reactive sputtering with pure Zr and W metal targets and Ar plasma and N 2 reactive gases. Experiments using the grey-Taguchi method are conducted to study the effects of deposition parameters (substrate plasma etching time, N 2 /(N 2 + Ar) flow rate, deposition time and substrate temperature) on a film that is deposited on a cutting tool that is used for dry machining and on the films' mechanical properties. The substrates' surfaces are etched using oxygen plasma pretreatment. It is clear that the coated film is homogeneous, very compact and exhibits perfect adherence to the substrate. The results of grey relational analysis show for the dry turning AISI 304 stainless steel that the surface roughness is approximately R a = 0.70 μm and that the flank wear is approximately 14.02 μm. The grey relational analysis shows that the period for which the substrate (tungsten carbide tool) is under plasma-etched pretreatment has the most significant effect on both the surface roughness and flank wear. The coated films are analysed using scanning electron microscopy (SEM), energy-dispersive spectroscopy (EDS), transmission electron microscopy (TEM), X-ray diffraction and a nano-indenter. The ternary nitride (ZrWN)-coated specimens exhibit better mechanical properties than binary nitride (ZrN and WN) specimens. The optimum ZrWN coating exhibits the greatest hardness (H), elastic modulus (E) and H/E values.
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