Advanced Materials Research Vol. 939

Abstract: In the straightness profile measurement of a mechanical workpiece, hardware datums have been the traditional standard. However, when the straightness profile is measured using a scanning displacement sensor set on an X-stage as the hardware datums, output of a displacement sensor includes the signal of straightness profile and the sensor’s parasitic motion, i.e. straightness error motion. Then, error separation techniques of the straightness profile from parasitic motions have been developed. For example, two-point method uses two displacement sensors and separates the sensor’s straightness error motion from the straightness profile. However, the conventional two-point method cannot measure a large-scale workpiece because the large sampling number causes random error amplification. In this article, the influence of the random error of generalized two-point method is shown. As the result of the theoretical analysis and numerical analysis, random error propagation decrease when sampling number increase. Further, experimental results obtained by generalized two-point method with large sampling number are analyzed using Wavelet transform and influence of error of the generalized two-point method is discussed in the space-spatial frequency domain.

Abstract: In this paper, we design a service robot which not only can plan road to a destination by itself, but also can take an elevator to every floor. For planning road, in order to solve the Hagisonic Stargazer Robot localization system problem which in large environment will need to set a lot of landmark and this way will increase the lead time and memory capacity. So we use the concept of road nodes to combine with Stargazer landmark and Dijkstra’s algorithm. Robot can localize by itself and can plan the shortest road to a destination. In dead region of Stargazer, we integrate with a laser range finder and e-compass to assist robot in navigation, and use the laser range finder simultaneously to avoid front obstacle. For taking elevator, we design a wireless control of independent mechanism. Robot can use Xbee transmit command to control servo motor to push elevator button and use RFID to determine whether the arrival task Floor. Last, we use Borland C++ Builder to design a Human–Computer interaction. People can operate monitor to choice receiver, and we add the functions of remote call and setting code which can increase the practicability of this service robots.

Abstract: In this paper an advanced semi-active damper is designed and experimentally studied to investigate and establish its behavior. A prototype Magneto-rheological fluid Damper is designed as advanced semi-active damper due to its huge advantages. Magneto-rheological fluid with improved dispersion stability is prepared here as smart fluid. The relation between force and displacement for various current has been established to develop the semi-active damper model. In this study a fuzzy tuned PID controller is opted to achieve better response for a various frequency input. The proposed MR damper can be applied to vehicle syspension system and other suspension mitigation system widely. Moreover, the identified behaviour can help in further development of MR damper technology. The characteristics obtained from of MR damper is more realistic as it is obtained from experiments.

Abstract: This research develops a heuristic algorithm for assembly line balancing problem (ALBP) of stitching lines in footwear industry. The proposed algorithm can help to design the stitching line with workstations, machines and operators for the production of every new product model. Rank-positional-weighted heuristics and hybrid genetic algorithms are proposed to solve ALBP. First, the heuristics assign tasks and machines to workstations. This solution is then used as an initiative population for hybrid genetic algorithm for further improvement. Real data from footwear manufacturers and experimental designs are used to verify the performance of the proposed algorithm, comparing with one existing bidirectional heuristic. Results indicate that when the size and shape of shoes increase, the proposed genetic algorithm achieves better solution quality than existing heuristics.Production managers can use the research results to quickly design stitching lines for short production cycle time and high labor utilization.

Abstract: Hydrogen is known to be an ideal fuel that provides zero-emission energy. Fuel cells have emerged as one of the most promising candidates for fuel-efficient and emission-free vehicle power generation. PEMFC stacks require liquid cooling which can be operated in an open-cathode mode with air supplied by one or several fans, thus reducing the overall complexity of the PEMFC system. In this study, an open cathode PEMFC is used as the dependable power source and experiments are carried out to investigate the temperature characteristic of open cathode PEMFC. Combined with the using of oxidant and cell stack cooling, the optimal air fan supply voltage is 9.0V, and the maximal power can be obtained is 355W.

Abstract: A number of materials have been used for Medical Additive Manufacturing (MAM), such as stem cells, biopolymers, metals, bio-ceramics, and bio-glass. Recent research includes potential applications in the replacement of human tissues, organs, and bones by using the bio-printing technology. MAM also has been applied to build up a dummy prototype to simulate a complicated operation process before surgery. Sustainable design of MAM has a need for the development of the system to be environmentally, economically, and socially sustainable for its life cycle. This paper surveys the scope of the sustainability of MAM in terms of these three categories. The methodology and tools for assessment of the sustainable development of MAM processes are discussed. This paper analyzes several examples of the application of additive manufacturing in medicine which have been published in recent journals. There are four critical areas of the design-centered system integration for sustainable development in this survey. The investigations for MAM processes including (1) the materials, (2) the precision of the advanced machine tools and tissues, (3) the mechanisms of the processes, and (4) the mechanical properties of the implanted components after MAM. The results can be used as a reference for the assessment of future sustainable Design-Centered Integration for MAM.

Abstract: Throughout the technological advancements, electronic devices are getting high dense and less expensive in day by bay. Thus, significantly reducing the production cost is the vital issue in order to produce more competitive device with maintaining its standard in all expect. Therefore, introducing new compact contact in high-Hertz stress with low normal force (LNF) will be a key technology to achieve the future goal. In this research, it is identified that only a 5μm radial tip with 0.1N force contact provides an excellent electrical performance which is much sharper than conventional connectors. This invention gives a big hope to produce less expensive and high dense Low Normal Force contact. The contacts durability test were also successfully passed 0.30 million cycles of uses while the contact resistance were ≦50mΩ.

Abstract: The present paper deals with the investigation of the mechanisms of TiO₂ nanotubes formation on titanium surfaces during anodization process. The samples were made of pure Ti Grade-2 and Ti-6Al-4V alloy. They were grinded, etched with 0,5 wt. % HF acid and anodized. The anodization was done in electrolyte containing 0,5 wt. % HF acid using DC power supply with graphite electrode as cathode. The samples were investigated by SEM, EDAX and XRD analysis. The results show two different mechanisms of formation of TiO₂ nanotubes on the surfaces of both materials. During the anodization process the oxide formations, obtained on the pure Ti surface after etching, are oxidized to nanorods; the area between them is also oxidized and connects them. This thin oxide layer grows in the metal depth while the nanorods are dissolved thus forming the porous sponge-like structure which is further transformed in tubular. While on the surface of Ti-6Al-4V alloy oxide nanonuclei originate which transform their shape from nanoseed to bowl-like with clearly pronounced bottom and walls, growing in tubular structures. The type of the material defines the surface morphology after etching. Thus obtained morphology influences on the processes running rate in different micro-regions determining origination of the titanium nanotubes on different stage as well as by different mechanism. The field-enhanced oxidation and field-enhanced dissolution are the main processes for formation of TiO₂ nanotubes during anodization. In the regions with prevalent oxidation processes the TiO₂ nanotubes are formed earlier while in the regions with dominant dissolution processes the TiO₂ nanotubes are formed on the later stage.

Abstract: Piezoelectric materials possess really high potential to deliver nanoscale or micro-scale positioning resolution, huge blocking force, and fast response; hence they are widely utilized in a variety of engineering applications and product designs. However, a higher and unacceptable positioning error always occurs due to the hysteresis effect of the piezoelectric materials. For high-precision applications, this natural behavior should be eliminated. For solving this problem, a nonlinear control design based on concepts of Bouc-Wen model, system identification, and the proportional-integral-derivative (PID) control design is proposed. The proposed control design can be divided into the following four steps: 1. Input and output behaviors of piezoelectric materials are firstly mathematically described with Bouc-Wen model, 2. System parameters in Bouc-Wen model for representing the characteristics of piezoelectric materials then simultaneously identified with respect to practical input and output data of piezoelectric materials, 3. Stability verification for this identified Bouc-Wen model should be done in the next, and 4. A PID control is elegantly derived finally via minimizing the tracking error performance index and is practically realized for nanoscale tracking design. One important contribution of this investigation is that the tracking error between output displacement of mathematical modeled piezoelectric materials and desired trajectory can be proven to exponentially converge to zero.

Abstract: This paper mainly focuses in the use of an atomic force microscope, research about the nanooxidation technique of conductive diamond-like carbon thin film in the atmospheric environment. The hardness, high wear resistance and chemical stability of diamond-like carbon thin film is high, and coefficient of friction is low, it is very suitable as a mold material for nanoscale mold. However, tool can only use a diamond cutter to machine the high hardness diamond-like carbon by traditional hard machining method, and tool life is not long. To overcome this drawback, the paper proposed an atomic force microscope (AFM) as a platform, a conductive AFM probe for tool under atmospheric conditions, and imposed nanooxidation technique on conductive diamond-like carbon thin film using electroluminescent etching to carry out nanofabrication processing. During the nanofabrication process, by changing the various processing parameters, such as applied voltage, repeated nanooxidation times and probe speed, etc., in order to understand the effect of processing parameters. The experimental results show, the nanooxidation technique can be carried out nanofabrication on conductive diamond-like carbon thin film successfully. And found that applied voltage, repeated nanooxidation times and probe speed all for the groove depth on the conductive diamond-like carbon thin films have significant influence. Additionally, this study successfully created a nanopattern. Therefore, the adequate machinability of DLC coating was achieved successfully in this study, indicating a promising application in the fabrication of nanopatterns on a nanoscale.