Jin-Wei Liang

• Ming Chi University of Technology

Unbalance faults are among the common causes of interruptions and unexpected failures in rotary systems. Therefore, monitoring unbalance faults is essential for predictive maintenance. While conventional time-invariant mathematical models can assess the impact of these faults, they often rely on proper assumptions of system factors like bearing sti...

Prognostics and Health Management (PHM) is a promising method of fault diagnosis for making maintenance decisions. For system fault development trends, different statistical or machine learning methods are being used. Unbalance is a fault that causes excessive vibrations in rotary systems, yet it cannot be totally eliminated. Thus, monitoring, and...

A machine learning-based prognostic strategy is developed in this paper for predicting the remaining useful life (RUL) of high-pressure packing in plunger-type hypercompressors. The proposed strategy applies principal component analysis (PCA) to identify the three most important sensors out of 33 possible options which seem relevant to the subject...

A novel model-based unbalance monitoring and prognostics for rotor-bearing systems is introduced in the paper. An analytical method is first applied for rotor modeling and the calculated first natural frequency is validated by an FEM model. The rotor-bearing model with the identified bearing parameters is next validated with an operational 3-stage...

Recently, prognostics and health management (PHM) has garnered a lot of attention in the industrial sector for its cost-effective maintenance and safe operation of the system. In this regard, vibration-based predictive maintenance using sensors plays a significant role in the diagnosis and prognosis of various faults. The need of the hour is to kno...

A machine-learning-based prognostic strategy is developed in this paper for predicting the remaining useful life (RUL) of high-pressure packing in plunger-type hyper compressors. The proposed strategy applies principal component analysis (PCA) to identify three most important sensors out of 33 that seem relevant to the high-pressure packing. Singul...

Robot manipulators play a very important role in today’s industrial automation. In this paper, a SCARA robot manipulator pick and place system was developed by integrating a vision system and control strategy. The vision system uses a digital image processing algorithm to identify various shapes, colors, orientation and depth of an object, it was p...

A collocated periodic vibration absorber-harvester (PVAH) is designed and the interaction between its absorption ability and harvesting capability is investigated. The PVAH consists of dual cantilever beams interconnected by a discrete spring. For energy harvesting purpose, both cantilever beams are partially covered with PZT layers. If the PVAH is...

Accurate estimation of lithium-ion battery life is essential to assure the reliable operation of the energy supply system. This study develops regression models for battery prognostics using statistical methods. The resultant regression models can not only monitor a battery's degradation trend but also accurately predict its remaining useful life (...

This paper presents the design, fabrication and control of a piezoelectric-type droplet generator which is applicable for on-line dispensing. The piezoelectric-actuated dispensing system consists of a linear piezoelectric motor (LPM) actuated table, a plastic syringe, a nozzle, a linear encoder and a PC-based control unit. Adaptive wavelet neural n...

This paper develops intelligent control for a diaphragm-type pneumatic vibration isolation (PVI) system. Functional approximation technique (FAT) is integrated with sliding-mode control design to capture unknown system dynamics and release the requirement of mathematical modeling. To deal with approximation error and system dynamics variation, an a...

This paper presents the design, fabrication and control of a piezoelectric-type droplet generator which is applicable for on-line dispensing. Adaptive wavelet neural network (AWNN) control is applied to overcome nonlinear hysteresis inherited in the LPM. The adaptive learning rates are derived based on the Lyapunov stability theorem so that the sta...

In this paper feedforward controller is designed to eliminate nonlinear hysteresis behaviors of a piezoelectric stack actuator (PSA) driven system. The control design is based on inverse Prandtl-Ishlinskii (P-I) hysteresis model identified using particle swarm optimization (PSO) technique. Based on the identified P-I model, both the inverse P-I hys...

This paper presents an intelligent control strategy to overcome nonlinear and time-varying characteristics of a diaphragm-type pneumatic vibration isolator (PVI) system. By combining an adaptive rule with fuzzy and sliding-mode control, the method has online learning ability when it faces the system's nonlinear and time-varying behaviors during an...

This paper develops intelligent control schemes for a diaphragm-type pneumatic vibration isolation system. The active-control schemes are applied to the pneumatic isolator to enhance isolation performances in the low-frequency range where passive techniques usually have difficulties in remaining effective, especially at the resonance frequency. The...

Recently, the micropositioner has become an important developing target for achieving the requirements of precision machinery. The piezo-actuating device plays a very important role in this application area. In this paper, a model-free adaptive sliding-mode controller is proposed for a 3D piezo-actuating system because of the system’s hysteresis no...

This study addresses the identification of nonlinear systems. It is assumed that the function form in the nonlinear system is known, leaving some unknown parameters to be estimated. Since Haar wavelets can form a complete orthogonal basis for the appropriate function space, they are used to expand all signals. In doing so, the state equation can be...

In this paper, a model-free adaptive sliding controller with fuzzy compensation is proposed for contour tracking control of a 3-D piezoelectrically actuated system due to the system's nonlinear and time-varying characteristics. This control strategy employs the functional approximation technique to establish the unknown function for releasing the m...

This paper aims to develop and implement intelligent control for a X-Y-Z three-dimensional table using linear ultrasonic motors as the actuators. Functional approximation technique (FAT) is integrated with the sliding-mode control design to capture the unknown system dynamics and release the requirement of mathematical modeling. In order to deal wi...

This work identifies damping parameters from compliant-contact vibration systems using an energy balance. To develop the identification algorithms, the energy loss as registered in the force–displacement relationship of the real system is expressed in terms of a theoretical model incorporating an ideal compliant contact. Two approaches, one based o...

In this paper, a function approximation technique (FAT) based adaptive controller is proposed for the tracking control of a piezoelectric-actuated X—Y table. Owing to the highly nonlinear behavior associated with the actuator, control problems involving a piezoelectric-actuated system are challenging. Moreover, a universal and effective hysteresis...

This article is concerned with the chaotic dynamics in a missile system. Five channels of acceleration signals were measured at different locations and/or orientations of the missile during a test flight. Based on these data, the existence of chaotic behaviour is determined using common techniques for nonlinear time series analysis, such as phase-s...

The piezoelectrically actuated system has non-linear and time-varying behaviour, hence it is difficult to establish an accurate dynamic model for a model-based sliding-mode control design. In this study, a model-free adaptive sliding controller is proposed to control the piezoelectrically actuated system. This control strategy uses the functional a...

Since the piezoelectrically actuated system has nonlinear and time-varying behavior, it is difficult to establish an accurate dynamic model for a model-based sensing and control design. Here, a model-free adaptive sliding controller is proposed to improve the small travel and hysteresis defects of piezoelectrically actuated systems. This sensing an...

In this paper, a model-free intelligent controller is proposed to control the piezoelectrically actuated system. This control strategy employs the Haar wavelet functional approximation technique (FAT) to establish the unknown function for releasing the model-based requirement of the sliding mode control. In addition, an adaptive fuzzy scheme with o...

In this paper, a model-free FAT-based adaptive sliding controller augmented with fuzzy compensator is proposed to control a piezoelectric-actuated X-Y table system. The control strategy employs the functional approximation technique (FAT) to capture features of the system dynamics and release the requirements of model knowledge prior to controller...

In this paper, a function approximation technique (FAT) based adaptive controller is proposed for tracking control of a piezoelectric-actuated X-Y table. Due to nonlinear hysteretic behaviors associated with the system, control problems involving piezoelectric actuator (PA) are challenging. Moreover, universal and effective hysteresis model for the...

In this paper, a stator flux oriented current vector control of a sensorless three-phase 6/4 switched reluctance motor without position sensors is presented. Space current vector control technology based on torque angle estimation was used to reduce the acoustic noise and vibration of the motor drive system. The power converter for the 6/4 switched...

The fuzzy sliding-mode control strategy is used to tackle tracking problem of a piezo-actuated stage in this paper. The piezo-actuated system is composed of the piezoelectric actuator and a positioning mechanism. Due to hysteretic nonlinearity of the piezoelectric actuator, the tracking accuracy of the system is limited. To compensate for this nonl...

A novel adaptive sliding-mode controller integrated with Haar-function-approximation technique is proposed to attack tracking problems of a piezo-actuated system. Unlike conventional model-based approaches, the method proposed here can achieve sliding-mode controller design without the knowledge of the hysteresis model. To design the adaptive slidi...

In this study, simple PI and fuzzy-sliding-mode controllers incorporating a memory-based learning control scheme are proposed to resolve tracking problem of a piezo-actuated system. Unlike traditional model-based approaches, which require precise inverse model in order to cancel out undesirable hysteresis effects, the methods proposed here are mode...

This paper extends an existing single-degree-of-freedom (dof) energy-dissipation scheme to identify damping parameters for multiple-dof vibration systems. The method balances the energy input of the real system against the energy dissipated in a theoretical model to develop the identification algorithms. The theoretical friction model is assumed to...

This study makes use of an energy balance to identify damping parameters in mechanical vibration systems. By balancing the energy input as registered in the force–displacement relationship of the real system against the energy lost theoretically in a damping model with unknown parameters, the identification algorithms are developed. We apply the es...

A new damping-identification method for the simultaneous identification of Coulomb and viscous damping effects from free-vibration acceleration decrements in a damped linear single degree-of-freedom (dof) mass-spring system is presented. In deriving the algorithms, the governing differential equations are solved to come up with two schemes separate...

Wavelet transforms were compared between various simulated friction models and real stick-slip data. While simulations of several models produced stick-slip transition oscillations seen in the real data, the wavelet features of the compliant contact model with light damping best captured the characteristics of the experimental signal. The wavelet c...

This paper presents a method for estimating Coulomb and viscous friction coefficients from responses of a harmonically excited dual-damped oscillator with linear stiffness. The identification method is based on existing analytical solutions of non-sticking responses excited near resonance. The method is applicable if the damping ratio of viscous co...

This paper aims at determining whether chaotic dynamics exist in a flying vibratory system. It is important to identify chaotic behavior in a flying system since it may jeopardize the structure of the flying object and cause instability subsequently. It can also cause uncomfortable experience for passengers in a passenger airplane or inaccurate tar...

This work investigates a base-excited Coulomb oscillator with contact compliance and inertia. The full-order system is a two degree-of-freedom (DOF) problem. The study first shows that two existing approximate models, including the rigid-contact model (RCM) and the compliant-contact model (CCM) cannot closely capture the dynamical characteristics o...

This study makes use of energy dissipation to identify damping from mechanical vibration systems. Both the viscous damping and dry friction are assumed to coexist in vibration systems. By balancing the energy loss as registered in the force-displacement relationship of the real system against that of a theoretical model, consisting of viscous dampi...

This paper presents a method for estimating Coulomb and viscous friction coefficients from responses of an harmonically excited dual-damped oscillator. The identification method is based on analytical solutions of non-sticking responses excited near the natural frequency. It is applicable if the damping ratio of the viscous component can be conside...

Introduction Characterizing macroscopic low-order friction behavior is important in many engineering tasks, such as those involving control, and squeak and squeal prediction. Two schools of thought for measuring macroscopic friction forces involve the employment of a load cell and the calculation of friction force by measuring motion signals and ap...

This paper proposes a simple identification algorithm for estimating both viscous and dry friction in harmonically forced single-degree-of-freedom mechanical vibration systems. The method is especially suitable for the identification of systems for which the traditional free-vibration scheme is difficult to implement. Numerical simulations are incl...

Contact compliance, which may arise from elastic deformation near the contact point or in the surrounding structure, affects the dynamical friction behaviors in mechanical oscillators. An idealized model consisting of a mass sliding harmonically on a mass-less compliant contact produces hysteresis in friction-velocity plots. Dynamical friction feat...

This study focuses on an algorithm for the simultaneous identification of Coulomb and viscous damping effects from free-vibration decrements in a damped linear single degree-of-freedom (DOF) mass-spring system. Analysis shows that both damping effects can indeed be separated. Numerical study of a combined-damping system demonstrates a perfect match...

Nonsmooth processes such as stick-slip may introduce problems with phase-space reconstructions. We examine chaotic single-degree-of-freedom stick-slip friction models and use the method of delays to reconstruct the phase space. We illustrate that this reconstruction process can cause pseudo trajectories to collapse in a way that is unlike, yet rela...

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This paper addresses the effects of a compliant contact on the dynamical friction behaviors in mechanical systems. Contact compliance is due to the elastic deformation at the contact point or the surrounding structure. This paper is divided into two parts. The first part focuses on oscillations with continuous macroscopic sliding. An idealized mode...

The dynamic behavior of the transition between slipping and sticking motions of a mass-spring system with dry friction is studied numerically and experimentally. Three mathematical models of dry friction are incorporated in the forced oscillator's equation of motion. The wavelet transform is used to analyze response signals for both high and low fr...