Key Engineering Materials Vols. 480-481

Abstract: Electrochemical machining is a process combined with electrochemical and mechanical actions. It has the advantage of higher efficiency, lower surface roughness, better quality and simpler equipment etc. According to the current development, topology optimization was introduced for the improvement of electrochemical machine tool and applied by the ANSYS software in this paper. Based on the result of the topology optimization, some improvement was done to the electrochemical machine tool. On the basis of the new FE model of the improved machine tool, the modal analysis and static analysis were carried out. By the comparison of the results between the former and latter, the weight of the machine tool is substantially reduced while the stiffness and strength reserved.

Abstract: Data acquisition is very important for control precision of micro-positioning platform. Based on LabVIEW, a kind of MSMA (Magnetically Controlled Shape Memory Alloy) test platform was developed, and the data acquisition, programming and testing was studied. The deformation mechanism of MSMA was analyzed, and the characteristics of MSMA were obtained by experimental study, the relationship curves between displacement and current, and the curves between magnetic field and current were tested. Experiments show that the test platform for intelligent materials is excellent and reliable, and the paper provided a good research platform for the study on properties of intelligent materials.

Abstract: Eddy current retarder was a retarder braking set used in an automobile, and it can transform kinetic energy or mechanical energy of the automobile into heat energy, and heat energy was emitted around environment by the blades founded in the rotor of eddy current retarder, so flow field within the blade had direct effect on heat elimination and braking performance. In this paper two styles of 2D computational model for the rotor had been established. The flow field between and out of blades were analyzed by using RNG Κ-ε model and energy equation. The velocity distribution, pressure distribution between blades, static pressure on work face and rear face of the blade along radial direction all were accepted. The pressure, velocity and air flux for two styles of the blades had been compared. Numerical analysis of flow field was in favor of improved structure design for the blade.

Abstract: Tube hydroforming has been widely used in auto industry due to its remarkable advantages compared with conventional manufacturing via stamping and welding. The forming limit stress diagram (FLSD) which is independent of strain paths is of great significance to tube hydroforming. The FLSD of 2008T4 tube blank was established to predict fracture defect in T-shaped tube hydroforming simulation. By numerical simulation method, the stress limit and strain limit were analyzed and fracture defects were predicted. Two prediction results of the fracture defects location were the same yet the limit pressure values corresponding to fracture were different. The FLSD prediction result was close to the experiment result, so the accuracy of FLSD as tube hydroforming limit criterion was proved.

Abstract: Currently, monitoring customs declaration with limited examination of imported goods by available scarce resources poses considerable challenge to the customs authority worldwide. This a positive impact on international trade and foreign investment of a country to find out the limited factors of customs clearance, put forward the improved solution and enhance the efficiency of customs clearance efficiency of port logistics. This paper presents a classification model, which is a sort of data mining technology, to analyze the risk of commodity through customs clearance, and builds a classifier of customs inspection as the reference for customs inspection and monitoring. And the classification model based on BP neural network is established and evaluated through experiments, which are proved that a classification data mining method can be used for risk evaluation on customs clearance business to improve the customs inspection and monitoring.

Abstract: Machining center on-line inspecting technology is an effective means that can improve precision and efficiency of machining center, which effectively integrates machining and inspection, makes machining center with partly inspecting function of coordinate measuring machines and improves the degree of inspecting automation compared with manual inspection and off-line inspection. Machining center on-line inspection system based on workpiece has been successfully developed and applied in SSK-U6035 five-axis machining center for palm inspection and control. The application result shows that machining center on-line inspection system based on workpiece can realize integration of machining and inspection more efficiently, increase precision and production efficiency, and reduce the rate of rejection and tool damage. At the same time, the on-line inspection system increases the additional function of the machining center for the manufacturer of machining center, improves the automation degree of the inspection and provides a new inspecting approach for other specific type’s workpiece.

Abstract: MAV (Micro Air Vehicle) can be used for many applications such as the investigation of inhospitable environments, regions contaminated by nuclear pollution or hazardous material and other inaccessible areas. For such kind of purposes, a small machine that can autonomously fly seems to be appropriate. Our MAV research group selects a Quad-Rotor MAV as our platform, and achieved automated take-off, landing, hovering, way-point navigation, vision-based navigation flight. However, the payload of our current platform is low (about 500grams), and the flight duration is only about 10 minutes. To overcome these obstacles, we designed a Six-Rotor type MAV with 770mm of diameter, 1.9Kg of weight, 1.5Kg of payload and 12 minutes of flight duration (without payload). In this paper, we present the main design considerations which are essential for the construction of Six-Rotor type MAV and attitude controller design technique.

Abstract: Sensor deployment problem for target location estimation is important for sensor networks which fulfill the monitoring tasks. In this paper, we investigate the deployment schemes which guarantee the location estimation accuracy of an arbitrary point within the region, by connecting the location estimation problem with the perspective of k-coverage problem. Our strategies are deploying sensors to guarantee the location-estimation accuracy of an arbitrary point within the monitored region, and to minimize the number of required sensors. Compared with the random deployment, the deterministic deployment provides a better solution to guarantee the location-estimation accuracy over the monitored region. Regular space deployment patterns in 2-dimension, i.e. equilateral triangle, square and regular hexagon, are discussed. The relationship between deployment density and vacancy ratio are derived by mathematical analysis. The derived required sensors deployment density to an arbitrary vacancy ratio for location-estimation coverage provides useful guidelines for sensor network deployment when location-estimation system is required for any practical application.

Abstract: Micro-displacement manipulator consists of piezoelectric actuator and flexure hinge is being widely used in precision positioning technology for its high resolution of displacement, high stiffness and fast frequency response. However, the hysteresis nonlinearity of actuator and vibration limited its control accuracy. In order to improve the positioning precision, the relationship between input voltage and output displacement was studied, the hysteresis nonlinearity was described by mathematical method, and a closed-loop controller was proposed to control the hysteresis and vibration. Experiment results revealed the proposed closed-loop controller can enhance the control precision of micro-displacement manipulator.

Abstract: It is of great significance to digitize ancient paintings and calligraphy. A typical way to acquire them is photographing the painting block by block and then stitching the photos together. Currently, all the algorithms to register photos are based on affine transformation parameters estimation. But these kinds of solutions have great error when the painting is rugged and scanned at high definition. A ruggedness of only 5 millimeters and 300 PPI scanning will cause the stitching error of 17 pixels for the adjacent photos. In this paper, first, the correctness of affine transformation of corresponding point on photos of a planar object is proved. Then, for non-planar object, the error equation is conducted. After that, an algorithm to correct the error due to perspective projection is proposed. The key to correction algorithm is to compute the difference between the perspective projection and parallel projection. With it, a virtual photo of infinite focal length is generated and the error is eliminated.