Experimental PC based TGPID control method for 2D CNC machine

An important problem in the control of circular motion of CNC machine is to let X and Y axes move simultaneously. This article addresses this problem for the performance of desktop-scale CNC milling machine for reducing roundness error (REB), minimizing position time difference (DTt). An approach that can solve those problems will be introduced. Our approach uses a Taguchi–Grey System–Proportional Integral Derivative (TGPID). This method emphasizes an improvement of system performance through this controller’s robustness, such as a faster initialization in gaining as appropriate local minima and also high responsive. In this paper, it is aimed to enhance on multi-performance characteristics, namely actual radius (R_act) and position time (Tt). The improvement of roundness error in counter-clockwise (CCW) direction is from 0.151 mm by default, being 0.140 mm by TPID (Taguchi–PID; without grey system), and 0.133 mm by TGPID. The method can reduce the roundness error significantly, also the difference of position time for 100%. This proposed method also offers a simple experimental-based approach. An improvement of its performance indicated that this proposed approach is applied successfully to multi-linear motion performance optimization which is determined by many parameters at multi-quality performances. Performances of the proposed controller scheme, as well as some practical design aspects, are demonstrated by the control of a circular motion of CNC machine

Experimental approached optimisation of a linear motion performance with grey hazy set and Taguchi analysis methods (GHST) for ball-screw table type

In end effect to control a path, tracking, or cutting motion of CNC milling machine or other applications of machine tools, controlling its actuator, specifically a linear table motion, becomes a classical matter to be solved in industries. By applying an optimisation of grey hazy set Taguchi (GHST) analysismethods, itmight get a performance improvement of a linear motion of ball-screw table type. In this paper, it is aimed to enhance on multi-performance characteristics, namely, displacement, velocity and torque. An improvement of an average error of position accuracy is from the 0.2100 to 0.0137 mm (S/N ratio from 13.4023 to 37.1935 dB). Average error of position time is significantly improved from 0.1599 to 0.0293 s (S/N ratio from 15.9229 to 29.9305 dB). The average error of torsion standard deviation from 0.0924 Nm is improved to 0.0481 Nm (S/N ratio from 20.5970 to 26.3447 dB). This study indicated that GHST analysis approach might be applied successfully to table motion performance optimisation, which is determined by many parameters at multi-quality performance

Crystallization, melting and morphology of PEO in PEO/MWNT-g-PMMA blends

Abstract The dispersion of multi-walled carbon nanotubes (MWNTs) in crystalline poly(ethylene oxide) (PEO) is significantly improved by grafting with poly(methyl methacrylate) (PMMA) on surface of MWNTs via emulsion reactions. The synthesized MWNTs-g-PMMA is soluble in solvents that can dissolve PMMA and is well dispersed in PEO. The effects of the MWNTs-g-PMMA on PEO crystallization and its use as a reinforcement for PEO are investigated using DMA, DSC, POM, and SAXS. DMA data show that the PEO/MWNTs-g-PMMA blends containing up to 30 wt% MWNTs-g-PMMA are compatible. DSC data show the crystallization of PEO is enhanced by the MWNTs-g-PMMA, accompanying with a decreased thickness of crystal layers and an increased thickness of amorphous layers of the PEO lamellar stacks, in combination with SAXS data.

Preparation, Characterization, and Properties of Polyurethane-Grafted Multiwalled Carbon Nanotubes and Derived Polyurethane Nanocomposites

We incorporated hydroxyl groups into the polyurethane backbone and then used the “grafting to” approach to functionalize the multiwalled carbon nanotubes (MWNTs) via the esterification reaction between MWNTs and segmented polyurethanes (PUs). X-ray photoelectron spectroscopy (XPS) spectra showed that the sidewalls of MWNTs had been functionalized with acid treatment, and the amount of COOH increased with increasing acid treatment time. FTIR spectra further confirmed that PU was covalently attached to the sidewalls of MWNTs. The functionalized acid amount and the grafted PU amount were determined by thermogravimetric analyses (TGAs). Comparative studies based on SEM images of the PU-functionalized and chemically defunctionalized MWNT samples also revealed the covalent coating character. Dynamic mechanical analysis (DMA) of nanocomposite films prepared from PU and PU-functionalized MWNTs showed enhanced mechanical properties and increased soft segment . Tensile properties indicated that PU-functionalized MWNTs were effective reinforcing fillers for the polyurethane matrix

Temperature-, pH- and CO2-Sensitive Poly(N-isopropylacryl amide-co-acrylic acid) Copolymers with High Glass Transition Temperatures

A series of poly(N-isopropylacrylamide-co-acrylic acid) (PNIPAAm-co-PAA) random copolymers were synthesized through free radical copolymerization in MeOH. The incorporation of the acrylic acid units into PNIPAAm tended to enhance the glass transition temperature (Tg), due to strong intermolecular hydrogen bonding between the amide groups of PNIPAAm and the carboxyl groups of PAA, as observed using 1H nuclear magnetic resonance (NMR) and Fourier transform infrared (FTIR) spectroscopic analyses. The lower critical solution temperature (LCST) increased upon increasing the pH of the aqueous solution containing PNIPAAm-co-PAA because the COOH groups of the PAA segment dissociated into COO− groups, enhancing the solubility of the copolymer. In addition, high-pressure differential scanning calorimetry revealed that the LCSTs of all the aqueous solutions of the copolymers decreased upon increasing the pressure of CO2, suggesting that CO2 molecules had displaced H2O molecules around the polar CONH and COOH groups in PNIPAAm-co-PAA, thereby promoting the hydrophobicity of the copolymers in the aqueous solution. In addition, the values of Tg of a film sample increased upon treatment with supercritical CO2, implying that intermolecular interactions in the copolymer had been enhanced after such treatment

Carboxymethyl chitosan has sensitive two-way CO2-responsive hydrophilic/hydrophobic feature

[[abstract]]Carboxymethyl chitosans (CMC) with various degrees of carboxymethyl substitution were prepared and investigated on their changes in water solubility in response to bubbling of CO2 or N2 as a function of the relative concentrations of COOH and NH2 side groups. When having similar concentrations of COOH and NH2, the produced CMC was water soluble at pH 10 and consecutively experienced peculiar dissolution-to-precipitation-to-dissolution during bubbling of CO2, and experienced reverse dissolution-to-precipitation-to-dissolution process during subsequently bubbling of N2. With the concentration of COOH much higher than that of NH2, the water soluble CMC at pH 10 exhibited no phase changes in response to bubbling of CO2 and N2. This newly developed CMC solution system with novel CO2 responsive amphiphilic feature has a potential use as a CO2 switchable surfactant to control interface of mixtures of hydrophilic and hydrophobic species in emulsification/demulsification applications.[[notice]]補正完