Showing papers by "Yuan Kang published in 2009"

The tribological behavior of modified diamond nanoparticles in liquid paraffin

Abstract: Purpose – The purpose of this paper is to discuss the dispersion capacity and tribological behavior of liquid paraffin added by diamond nanoparticles.Design/methodology/approach – The structure of the modified diamond nanoparticles which are prepared by oleic acid (OA) is observed by scanning electron microscopy (SEM) and infrared spectroscopy (IR). The dispersivity of these nanoparticles in liquid paraffin is measured by nanoparticle analyzer. The tribological behavior of adding diamond nanoparticles in liquid paraffin is evaluated by using a ball‐on‐ring wear tester.Findings – The measurement results reveal the dispersion capability of OA modified diamond nanoparticles and indicate the dispersing stability in liquid paraffin of the OA which is bonded to the surface of diamond nanoparticles through esterification. It is found from wear testing results that the diamond nanoparticle as additive in liquid paraffin at proper concentration shows better tribological properties for anti‐wear (AW) and antifricti...

Parametric Analysis and Impulsive Synchronization of Fractional-Order Newton-Leipnik Systems

Abstract: In this paper, the influences of parameters on the dynamics of a fractional-order Newton-Leipnik system were numerically studied. Impulsive synchronization of two fractional-order Newton-Leipnik systems was also investigated. The ranges of the parameters used in this study were relatively broad. The system displayed comprehensive dynamic behaviours, such as fixed points, periodic motion (including periodic-3 motion), chaotic motion, and transient chaos. A period-doubling route to chaos in this study was also found. Sufficient conditions on synchronization of the two systems are provided and illustrative example is given.

Modified recurrent neuro-fuzzy network for modeling ball-screw servomechanism by using Chebyshev polynomial

Abstract: This paper proposes a Chebyshev functional recurrent neuro-fuzzy (CFRNF) network to identify a nonlinear system, which is composed of nine layers network and a six-layer Chebyshev recurrent neural network (CRNN) used to emulate nonlinear system is one of nine layers. Based on Takagi-Sugeno-Kang (TSK) fuzzy model, the nonlinear dynamics of this system can be addressed by enhancing the input dimensions of the consequent parts in the fuzzy rules due to functional expansion of a Chebyshev polynomial. The back propagation algorithm is used to adjust the parameters of the antecedent membership functions as well as those of consequent functions. For a real system of ball-screw servomechanism with nonlinearity of stick-slip motion, the analytical and experimental results indicate that the accuracy and convergence of the CFRNF are superior to those of the identification results by adaptive neural fuzzy inference system (ANFIS) and recurrent neural network (RNN).

The Influence of Orifice Restriction on the Stability of Rigid Rotor-Aerostatic Bearing System

Abstract: This paper has studied the influence of the restriction effect on the stability of a rigid rotor in rotation supported by double-row, orifice compensated aerostatic bearings. The air which is assumed to be perfect gas, passes through orifice restrictor into the bearing clearance undergoing the adiabatic process is governed by Reynolds equation including the coupled effects of wedge due to spindle rotation and squeezed film due to journal oscillation. The Ph-method is used to analyze Reynolds equation and which is then solved by the finite difference method and numerical integration to yield static and dynamic characteristics of air film. The motion equation of the rotor-bearing system is obtained by using the perturbation method and the eigensolution method is used to determine the stability threshold and critical whirl ratio. The variations of stability threshold of both critical inertial force and critical whirl ratio with restriction parameters are analyzed for various whirl ratios, speed of journal rotation and eccentricity ratios.© 2009 ASME

Study on the Affection of Gear Fault Diagnosis Bases on HHT by Noises

Abstract: The signal is processed by using empirical mode decomposition (EMD) and Hilbert transformation (HT), which can obtain instantaneous frequency, instantaneous amplitude and marginal spectrum as the basis of pattern matching. Simultaneously, the energy distribution of signal at each frequency domain can be used to train a neural network as fault diagnosis tool. However, the influence of noise on EMD of gear operation signal is large. The noise may disturb EMD and generate the mix mode and. In this study, wavelet packet de-noises and Ensemble EMD (EEMD) is used to reduce the influence of noise on EMD. The diagnosis results display these two methods can improve gear fault diagnosis.

Rotary table in limited rotation

Abstract: This invention is a angular servo mechanism with auto-transmission for a rotary worktable which rotates within a limited range. A traditional rotary table is transmitted from the handwheel to the worm via a rotating rod, and the worm transmits the rotation to matched sector gear which is fixed on rotary table. Due to the backlash of the worm and gear, rotary table cannot be controlled to a precise position. Also, human may cause mistakes frequently. In order to remove the disadvantages and promote servo precision and the transmission efficiency of the rotary table, this invention of design is proposed. The invention issues are composed of ball screw mechanism and slider on crank mechanism. The ball screw mechanism is composed of motor, shaft, ball screw, carriage, rotary pivot and bearing. The slider on crank mechanism is composed of sliding jacket, rotation bearing, rotary pivot and pivot bearing. Rotary table is mounting on the pivot bearing which is located on the table base with innerring being fixed. The rotary table is supported by plain bearing or rolling bearing manufactured on a circular rack. The transmission power of rotary table is driven by motor which drives ball screw to carriage. The rotary table and sliding jacket are assembled in a floating fit manner by a pivot bearing. A rolling bearing is equipped in the sliding jacket which is rolling in the groove of table, which makes rotary table to rotate about the center of pivot bearing. The angular positions of rotary table which is servoed by encoder feedback can be controlled accurately and automatically. The encoder feedback can also displayed for rotational angle of rotary table on the monitor screen for the observation of the angular position during table adjustment by manual.

Numerical Simulations via Navier-Stokes Equation for Estimating Effects of Recess Geometry, Restrictor Dimension and Surface Speed on Static Characteristics of Hybrid Bearing

Abstract: This paper researches the influences of two recess geometry and restrictor dimensions on the flow patterns and pressure distribution of lubricant film, which are coupled effects of hybrid characteristics of a hydrostatic bearing, by using the numerical simulation method. Analyze the results to understand the characteristics and the reasons of flow patterns of recess and calculate the loading capacity. The research gets the design parameter of increasing the loading capacity.