Yefa Hu

Resource Service Composition and Its Optimal-Selection Based on Particle Swarm Optimization in Manufacturing Grid System

In distributed manufacturing systems, especially in a manufacturing grid (MGrid) system, there are primarily two kinds of manufacturing tasks (or resource service requests): (1) single resource service request task (SRSRTask), which can be completed by invoking only one resource service, and (2) multi-resource service request task (MRSRTask), which is completed by invoking several resource services in a certain sequence. For an SRSRTask, the system searches the resource services that are qualified for its function requirements and chooses the optimal one to execute it. For an MRSRTask, in addition to the search for all qualified resource services according to each subtask, the system selects one candidate resource service for each subtask. Then the system generates a new composite resource service (CRS) and selects the optimal resource service composite path from all possible paths to execute the task with the given multi-objective (e.g., time minimization, cost minimization, and reliability maximization) and constraints. The above problem is defined as multi-objective MGrid resource service composition and optimal-selection (MO-MRSCOS) problem in this paper. The formulation is presented for an MO-MRSCOS problem to minimize execution time and cost, and maximize the reliability. The basic resource service composite modes (RSCM) for CRS are described, and the principles for translating a complicated RSCM into a simple sequence RSCM are presented for simplifying the resolving process and complexity of MO-MRSCOS. A new MGrid resource service composition and optimal-selection method, based on the principles of particle swarm optimization (PSO), is then proposed. The PSO follows a collaborative population-based search, which models based on the social behavior of bird flocking and fish schooling. The case study demonstrates that the proposed method is useful in solving MO-MRSCOS problems. The experimental results and performance comparison show that the proposed method is both effective and efficient.

An approach to manufacturing grid resource service scheduling based on trust-QoS

Manufacturing grid (MGrid) aims to solve the problem of distributed and heterogeneous manufacturing resource sharing and collaborative operation. Compared with traditional scheduling methods in distributed computing system such as computing grid, which emphasises execution time, the resource service scheduling in MGrid emphasises the manufacturing ability sharing, and requires higher resource service ability and reliability, therefore demands higher trust in MGrid resource service scheduling. In this paper, the measurement and evaluation models of trust-QoS in MGrid are proposed. A trust-QoS based MGrid resource service scheduling framework is proposed, followed by the scheduling algorithms. Simulation and algorithms performance comparison show that the proposed methods are sound on success rate and execution efficiency.

Study of failure detection and recovery in manufacturing grid resource service scheduling

A Manufacturing Grid (MGrid) system is different from a conventional distributed computing system due to its focus on larger-scale, distributed and heterogeneous manufacturing resource and service sharing, including equipment resources, application system resources, material resources, technical resources, public service resources, etc., where remote resource service scheduling (e.g., remote accessing, information communication) has a large influence on the MGrid quality of service (QoS). The probability of failure is higher in MGrid resource service scheduling and failures affect task execution and the quality of service of the MGrid fatally. Therefore, this paper focuses on failures in the MGrid resource service scheduling process. The potential failures that can occur during MGrid resource service scheduling are investigated. Thirteen failures are first defined in detail and are classified into four categories: (a) virtual-link-related failures, (b) resource-service-related failures, (c) task-related failures, and (d) application-related failures. A failure management system of the MGrid system is presented associated with its architecture. Corresponding detection mechanisms and methods for each defined failure are presented in detail, as well as the corresponding failure recovery methods. The implementation and simulation results indicate that our approaches are sound for promoting a successful scheduling rate and shortening the total execution time of the MGrid resource service.

A Prototype of Flywheel Energy Storage System Suspended by Active Magnetic Bearings with PID controller

In this paper, a prototype miniature of flywheel energy storage system is developed. The structure and dynamics characteristic of the flywheel energy storage system are discussed. The system consists of a disk-shaped rotor, active magnetic bearing (AMB), PED controller, displacement sensor and cabinet, etc. The rotor is suspended by three active magnetic bearings (AMB). A mathematical model of the system is deduced and each degree of freedom motion is treated separately for the control system. PID control is applied to the AMB. The experiments have been carried out to measure the dynamic response of the rotor to direct disturbance. The results indicate that the PID controller possesses good performance.

The Connotation of Manufacturing Grid & its key technology

The conception of MGrid (Manufacturing Grid) is to utilize resources distributed in heterogeneous systems and different places to collaborative manufacture product the market requires. The solution of it is to adopt grid technique, information technique and so on to realize the completely sharing all kind of geographical distributed and heterogeneous manufacturing resources in the form of the virtual enterprises. Based on the analysis of the requirements and technology driving force of the MGrid, the basic features and connotation of MGrid were discussed. The definition of the MGrid was discussed as well, the system structure of MGrid system is presented, and the levels for MGrid and its main functions are introduced. Finally the main research content, key technologies and related work of MGrid are proposed.

Effect of stacking sequence on the torsional stiffness of the composite drive shaft

Torsional stiffness is an important parameter judging the performance of composite drive shaft. In this paper, a new mechanical analytical solution of torsional stiffness for the composite drive shaft with balance laminate is derived based on classical lamination theory and mechanical analysis. Finite element analysis (FEA) has been used to calculate the torsional stiffness of carbon fiber-reinforced plastic (CFRP) drive shaft. A torsion test platform has also been constructed to measure the torsional stiffness of CFRP drive shaft specimens. Results of the mechanical analytical solution, FEA, and experiments show that the composite tube with the location of ±45° layers near to the outer surface is larger than the ones with the location of ±45° layers near to the inner surface. The effect of stacking sequence on torsional stiffness is larger in the thick-walled than that in the thin-walled composite drive shaft. The mechanical analytical solution can complement classical lamination theory which cannot reflect the effect of stacking sequence in calculating the torsional stiffness.

Fuzzy Control of a Semi-active Multiple Degree-of-freedom Vibration Isolation System

Semi-active isolation systems fill the gap between passive and active systems, delivering the versatility and adaptability of fully active systems, by expending a small amount of energy to change system parameters such as stiffness and damping. Magnetic suspension vibration isolation provides an excellent active isolation technology, and has shown useful characteristics including noncontact isolation, fast response, high reliability and long lifespan. However, because it is highly nonlinear and time variant, the control of magnetic suspension vibration isolation is an area that still requires further exploration. This paper presents a fuzzy control algorithm for a semi-active multi-degree-of-freedom vibration system. The fuzzy control is based on the minimization of the weighted sum of squared output forces. The output force response of the fuzzy, PID control semi-active vibration isolation system and passive system under the same excitation are simulated. The simulation results show that the fuzzy control system has much better performance in vibration isolation. An experimental platform is developed to test the performance of the magnetic suspension vibration isolation system and the proposed fuzzy control algorithm. The experimental results are found to be in good agreement with simulation.

Dynamic modeling of magnetic suspension isolator using artificial neural network: a modified genetic approach:

Active vibration isolation technology has been widely used to reduce vibration transmission in many different engineering systems. Magnetic suspension isolator (MSI), as an active isolation actuator, has shown advantages including non‐contact, high response frequency, high reliability and long life‐span. However, its potential has not been fully explored due to the nonlinear and hysteretic behavior in a dynamic environment, and there is limited research work in the area. This paper proposes a new artificial neural network (ANN)‐based approach to model the dynamics of MSI. A modified genetic algorithm (MGA) is developed to train the ANN to improve the model accuracy. Results clearly show that the ANN model with the MGA approach outperforms the back propagation (BP) approach and the analytic method based on the least squares fitting method.

Research on carbon fiber–reinforced plastic bumper beam subjected to low-velocity frontal impact

Lightweight and safety performance of automobiles are two important factors for automobile designs. In this article, a research on lightweight and crashworthiness of automotive bumper has been conducted. The carbon fiber–reinforced plastic bumper beam is considered to replace the traditional high-strength steel one. The low-velocity impact finite element simulations for the above two bumper beams are performed via LS-DYNA. Furthermore, the energy absorption capabilities and dynamic response characteristics of the carbon fiber–reinforced plastic bumper beam are investigated and compared with the steel one. The results show that the carbon fiber–reinforced plastic bumper beam is of the better energy absorption capabilities and dynamic response characteristics than those of the steel one; the weight has decreased remarkably close to 50%. Meanwhile, the effect of lay-up and wall thickness on the crashworthiness of the carbon fiber–reinforced plastic bumper beam under low-velocity impact is also studied in this article to select appropriate design schemes.

Study on Semantic-Aware Manufacturing Grid Architecture

In order to solve the knowledge-intensive problems in manufacturing industry, this paper introduces Semantic Web (SW) technology to Manufacturing Grid (MGrid). Resources and services in MGrid should be described in the well-defined meaning, so that computers can understand grid information to interoperate seamlessly. In the paper, a semantic-aware MGrid architecture (SAMGA) based on WS-Resource Framework (WSRF) is first presented, in which the stateless Web Services are semantically described using OWL-S and the stateful resources description are semantically enhanced using OWL. Then a semantic-enhanced information model is designed for SAMGA. At last, SAMGA is applied to the magnetic bearing resource and service sharing platform.