Applied Mechanics and Materials Vols. 16-19

Abstract: The remote monitoring system of the robot is mainly designed. Data and image are transmitted based on wireless local-area network (WLAN) and wireless CDMA public communication network and the robot is controlled under the corresponding way. In this paper, the collection and processing of image by DSP, the transmission of data by CDMA modem and the remote wireless control of the robot are described in detail.

Abstract: Aiming at the presently slow informationization development phenomenon in the drawing and coving workshop of textile enterprise, we analyze actual existing problems in production management and information development, use some theories and techniques to propose many solutions. According to the actual requirements of workshop, we implement a real-time monitoring and control system based on LAN. System’s structure and workflow, the key techniques within the system development are researched, the accuracy of production data is ensured by using numerical approximation theories. As proved by practice, the system's structure is simple, easy maintenance and low cost, meantime, furthermore, system can run stably, collect accurately production data, and its functions meet production control and information management of workshop needs.

Abstract: The surface micro-topography of micro-WEDM is random, disordered and multi-scale and has been proved that it is fractal with the characteristic of self-affinity within a certain scale on the basic of the fractal geometry theory. According to the characterization of W-M fractal function, the principles of three evaluation methods about power spectrum method, structure function method and wavelet criterion have been described. The advantages and disadvantages of them evaluating the fractal property of the surface micro-topography of micro-WEDM have been compared in this paper. The experimental results indicate that the wavelet criterion is more stable and dependable than the other two methods, so the fractal dimension D of the surface micro-topography of micro-WEDM has been calculated using it. The result shows that the fractal dimension has the tendency of decrease with the increase of root mean square deviation (Sq) value while it is not absolutely monotonic, which can be used as a beneficial supplement to traditional evaluation parameters of surface roughness.

Abstract: This paper investigated the feature of pre-shaving hob contour and the generated gear tooth profile. By tooth generation method, a complete geometry of the gear tooth can be mathematically derived in terms of the design parameters of the pre-shaving hob cutter. The mathematical model consisted of equations describing the generated fillet and involute profiles. The degree of undercutting and the radii of curvatures of a fillet were investigated by considering the model. Finally, a computer program for generating the profile of the gear teeth was developed by simulating the cutting methods. The methods proposed in this study were expected to be a valuable guidance for pre-shaving hob designers and manufacturers.

Abstract: Granite is a kind of typical discrete material, which experiences from continuous deformation stage, discontinuous deformation stage to fracture stage under sawing forces. Using discrete element method (DEM) to study the process of sawing granite will help us to understand the removal mechanism of granite from the microscopic point of view. In this paper, numerical uniaxial compression and three-point bending tests were conducted to determine the microscopic parameters of the granite specimen firstly, and then simulation was performed for sawing of the specimen. The sawing process, deformation characteristics of granite and the effect of initiation and propagation of cracks on fracture process of granite were investigated. The emphasis was laid on analyzing the variation of sawing forces under different sawing parameters. The simulation results agree well with that of experiments, indicating that DEM can reflect the external macroscopic change of granite by changing the internal microscopic structure. The conclusions in this study would be useful to the modeling of sawing processes and engineering applications.

Abstract: Processing precision of numerical control machine tool is decided by static rigidity and dynamic rigidity of spindle to a great extent. 3- D model of numerical control machine tool was established by using parametric modeling and virtual assembly function of Solidworks. Simultaneously, simulation and Experiment study of the spindle static rigidity was carried out, and practicability of the simulation analysis method was proved. The result indicates that the biggest deformation appears in the front of spindle. The static rigidity of spindle can been enhanced greatly by enhancing three carriage-feed system’s static rigidity of machine tool. The simulation for the dynamic rigidity of spindle indicates that the dynamic rigidity of spindle is uniformly distributed and resonance can be avoided effectively by the spindle when working.

Abstract: Kinematics simulation and characteristics of a new type of parallel robot manipulator (PRM) with two-dimension movement and one-dimension rotation are analyzed. The new PRM is proved to can realize expected movement, and have smooth movement curves of displacement and velocity. The moving platform center of the PRM can achieve a wide range of swing, and has a larger working space. According to the kinematics theory, the working space and singularity characteristic are analyzed. Simulation and analysis indicated that the working space of the new PRM in the form and position is not singular, and has good maneuverability, thus providing the foundation for practice application and product exploitation.

Abstract: The lateral stiffness of a car is 1/12 of frontal stiffness for a typical side crash, and the deformable space is smaller than frontal zone too. In order to study the safety characteristic of HSS in car side impact, the side impact test and simulation were respectively completed. The main factors which influence side crashworthiness were carried out and it’s also the basis for further research on the car body crashworthiness of side impact.

Abstract: The curve NC grinding methods in presnet are analyzed. On the basis of this, a new curve NC grinding method―region contact grinding (RCG) method is proposed. With this method, the contact point between grinding wheel and workpiece can be controlled in the given contact zone. The problom of grinding wheel's distortion which is produced by contact point excessively deviating from symmetrical central plane of grinding wheel can be overcome. In order to the grinding mode, a new interpolation algorithm―region equiangular linear interpolation (RELI) is proposed. Namely, in terms of the convex-concave property of processing curve, some grinding regions are divided. In each grinding region, the grinding wheel's swing angle within each interpolation cycle is evenly distributed. Thereby, in the process of grinding a convex-concave curve, grinding wheel's contact points totally locate in the range of contact zone angle.

Abstract: In order to enhance the accuracy of engine fault diagnosis, information fusion technology was applied and a novel combination method is proposed based on D-S evidence theory. The evidence groups were classified by evidence conflict coefficient, the importance of each highly conflict evidence was calculated, and the credibility of each evidence was determined with a distance function of evidence bodies. Then the weight value of each evidence was revised with its importance and credibility respectively. Finally, the Dempster combination rule was used to realize the information fusion. The effectiveness of the new approach proposed was verified by theoretical analysis and experiment research results. Comparing with D-S evidence theory and the improved synthesis formula, the new combination method is more efficient in improving the accuracy and the certainty degree of engine fault diagnosis.