Papers by Author: Dai Zhong Su

Abstract: A remote online machine monitoring system is developed across a desktop PC and mobile devices to monitor and control machine’s working conditions. A server-client network structure is constructed for real time communication between server and client modules. Within the server module, data I/O (input/output) communication is utilised to acquire machine condition data and to pass control commands to the machine-controller interface; feature extraction and decision making are applied to detect machine’s operating status. The server and client modules allow mobile users to remotely access the server via PDA and Wireless Wi-Fi connectivity to regulate the machine conditions by tuning the controller parameters. Remote communication between the modules with different platforms/operating systems is implemented by combining the Web Service application program interface with MXML-based cross-platform programming standard. The system developed is validated by a case study of monitoring the working conditions of an air-conditioning system.

Abstract: . Small and medium sized manufacturing enterprises (SMEs) are challenged with the task of producing customized products in a timely and cost-effective manner. Winning competitive advantage is an imperative strategy for SMEs to compete with large sized organizations. The purpose of this research is to establish a Web oriented system to help SMEs to gain a competitive position with particular focus on the issues of product life cycle, supplier selection and product design specification. This is achieved by integrating three models, including Customer-Manufacturer-Competitor Orientation Analysis, Strategy-Position based Supplier Selection, and Component Based Partial Product Design Specification, into the system with the support of Web techniques including Enterprise Java Beans (EJB), JSP, Java Servlet, Java application, etc.

Abstract: Condition monitoring of components is commonly required to evaluate integrity, manage maintenance and predict impending failure. The condition of many electrical and mechanical components is revealed by their thermal signature which can be reliably monitored by infrared camera. Thermal data obtained optically has the advantage of being non-contact so that moving mechanical parts and high voltage electrical components, including those located in hazardous environments or with difficult access, can be readily monitored. This paper proposes that data obtained by such methods is processed within a model in order to identify the imminent failure of a component or to estimate the probability that a component may exceed its operating tolerances at any given time within the remainder of its expected life.

Abstract: This paper describes the utilisation of multi sensor fusion model using force, vibration, acoustic emission, strain and sound sensors for monitoring tool wear in end milling operations. The paper applies the ASPS approach (Automated Sensor and Signal Processing Selection) method for signal processing and sensor selection [1]. The sensory signals were processed using different signal processing methods to create a wide range of Sensory Characteristic Features (SCFs). The sensitivity of these SCFs to tool wear is investigated. The results indicate that the sensor fusion system is capable of detecting machining faults in comparison to a single sensor using the suggested approach.

Abstract: Tribological properties of the urea grease containing nano-silica were investigated with a four-ball tester, and its noise characteristics were evaluated with a BVT-1 bearing vibration tester. The results showed that the nano-silica has good effects on friction and wear resistances, the urea grease with 3% nano-silica has the least value of friction coefficient, and the urea grease with 2% nano-silica showed the best wear resistance. A proper amount of nano-silica can decrease the noise of the urea grease, and when lubricated by the grease with 1% nano-silica, the bearing achieved its lowest noise level as well as the best velocity values of both intermediate and high frequencies.

Abstract: The pressure-viscosity relationships of phosphate synthetic oil and other two kinds of similar atmospheric viscosity synthetic oils were studied using ultra-high pressure capillary viscometer. The pressure-viscosity relationship of phosphate synthetic oil is much better than the other two kinds of synthetic oils. The impact of pressure on viscosity is not limited to purely physical factors. The pressure can cause a variety of chemical reactions in some cases. The investigation results of mechanochemistry of phosphate synthetic oil at high pressure reveal that the physical state of phosphate synthetic oil changed from liquid into glassy amorphous state under high pressure, and the color varied from transparent into milky white. The mechanochemistry of phosphate synthetic oil was analyzed using the infrared spectroscopy and gel permeation chromatography, and the results indicate that under high pressure, the oxidation reaction of phosphate synthetic oil occurred, and the molecular weight distribution changed with the increase of the low molecular weight region. The reason of the mechanochemistry phenomena was that phosphate synthetic oil molecular chain disconnects to inform great radical. The great radical has strong activity, and reacts with other free radicals acceptor (oxygen, etc).

Abstract: A remote real-time machine condition monitoring system is reported in this paper, which is applied for diagnosis and prognosis of gearboxes’ working condition. Within the system, the diagnostic classification is performed by pattern recognition using statistic parameters, and remote diagnostic capability is enhanced by applying Wireless Web technology. An online signal-processing scheme is adopted based on time-frequency analysis, digital filtering and statistic parameter algorithm to detect early fault signals of gears and to provide expert advice for decision making for maintenance. The effectiveness of the developed remote diagnostic system is verified via experimental investigation of monitoring a gearbox on a test rig under different conditions.

Abstract: With recent advances in wireless communication technologies, the world of mobile computing is flourishing with a variety of applications. This paper presents a mobile product information retrieval system that supports collaborative work among remote users. With the development of the system, a knowledge representation framework has been adopted which accommodates semantic relationships and similarity of product data. To illustrate the system developed, a case study in information retrieval for product design is presented．

Abstract: Most of the lubricants are made of mineral oil which has bad biodegradability, and, hence, seriously contaminate the environment. To minimise the lubricants’ impact on the environment, this research developed a new type of lubricant, titanium complex grease. Its base oil is the admixture of vegetable oil and mineral oil. Its production method and experimental results are presented in this paper. The friction, wear and physical-chemical properties of the grease were investigated. The morphology of wear scar of steel ball was observed using the sweep electron microscope. The results obtained contribute to the further development of environmentally friendly lubricants.

Abstract: The apparent viscosity of aircraft grease with different nano-particles content, temperature and shear rates were studied using a rotational viscometer. The rheological properties of two types of aircraft grease, the basic grease and the one with nano-particles additives, were investigated using a rheometer. The results indicated that the apparent viscosity increases with the increase of nanoparticle concentration with the given ratio of nano-particles added. It was also found that the grease with and without the nano-particles both have yield stresses and clear shear-thinning properties. The shear-thinning phenomenon of the grease containing nano-particles is more evident than that of the basic grease. The experimental results also reveal that the rheological characteristics of both types of grease fall in Herschel-Bulkley class, and the nano-particles have a significant influence on the rheological parameters. At the end, the rheology mechanism was discussed based on the entanglement and orientation theories.