Applied Mechanics and Materials Vols. 201-202

Abstract: This article mainly discussed the establishing process of the 4G15-6L automotive engine simulation model. The numerical model was set up for the engine using engine’s experimental data. Therefore the engine’s optimal economic and dynamic curves were drawn. According to the established mathematical model, the simulation experiment model can be built by Matlab or Simulink. The feasibility and reliability of the model were verified through the test, and the model met the requirements of hardware in loop simulation. Meanwhile, the model built the foundation of the engine’s simulation platform in the next step.

Abstract: Final testing procedures are performed to assure the quality of manufactured parts before their shipping to customers. Turret based test handler is a general kind of IC Test Handler for final testing. This paper discusses how to develop a general control system for a test handler of turret style in which every workstation moves up and down separately based on an industrial control computer. The combination of object-oriented programming and the cycling scanning working mode is the key of the whole system. To achieve ideal performance, special control flags are designed as an efficient way for making all the workstations work as setting orders stably. The method to developing the control system in this paper can be also applied to similar systems, which would greatly reduce development cycles. A turret based test handler with this control system has passed the test of a semiconductor factory and operates well in actual production.

Abstract: Comprehensive meshing stiffness and single tooth meshing stiffness are calculated by tooth contact analysis and load tooth contact analysis program. The corner meshing impact model is proposed. Nonlinear dynamic model of helical gear transmission system is established in this paper considering time-varying meshing stiffness excitation, transmission error excitation, corner meshing impact excitation, and the backlash excitation. Take the ship’s helical gear transmission system as an example, the mesh impact force is derived and the primary factors that produce noises are discussed. The effects which the mesh impact brings to vibration characteristics of the gear dynamic system are concluded. Meshing impact has an inevitable effect on the vibration of the dynamic system. Impact excitation costs 8.5% in maximum of vibration acceleration response, 31% in maximum of instantaneous acceleration, and 4.9% in maximum of spectral component amplitude.

Abstract: The objective is to provide a method about equipment condition monitoring and fault diagnosis. The method could indicate equipment operating parameters, working conditions and specific status. We used CDMS system monitoring mine hoist key parts of the vibration velocity, introduces the vibration sensor reasonable decorate, in the time domain analysis of speed amplitude values, in frequency domain speed spectrum analysis, according to the monitoring signal analysis processing results, give the diagnostic conclusions that the gear of second shaft have uniform force, and a little corrosion, peel and eccentric, puts forward that we should strengthen vibration monitoring about the second shaft of speed reducer, Observe reducer wear trend using the iron spectral analysis, Supervise lubricating oil quality, change oil when necessary.

Abstract: As object-oriented simulation software adopts event-driven simulation method, it can not show the logical and temporal relations among the objects clearly, and the formal description of the system is not sufficient, that leads to low reliability and the establishment of a perfect simulation model may need several modifications and debugging. According to the problems that exist in the object-oriented simulation software, a modeling and simulation technology is presented based on Petri Net and QUEST in this paper, which combines Petri Net’s rigorous description with QUEST’s visual feature. Base on the practical application requirements in visual C++ environment，to realize the integration of the object oriented Petri model and the QUEST model.

Abstract: This article is intended to provide a mobile loader, it is consist of spiral drum collecting device, chain transmission device, rotary table, expansion bend and mobile platform vehicle. design the rotary table which can rotate about a fixed axis relative to the mobile platform vehicle in the horizontal plane, and the expansion bend which can rotate about a fixed axis relative to the rotary table in the vertical plane, Combined with electrical control system and to realize the function requirements of the loader, it mainly used for coal mine underground sump cleaning, and focus on the structure, working principle and process of the spiral collection-scraper loader, point out the applicable working conditions and main features of the machine.

Abstract: A model machine of multifunctional form and position measurement instrument controlled by a personal computer has been successfully developed. The instrument is designed in rotary table type with a high precision air bearing and the radial rotation error of the rotary table is 0.08 μm. A high precision vertical sliding carriage supported by an air bearing is used to the instrument, the straight motion error of the carriage is 0.3 μm/200 mm and the parallelism error of the motion of the carriage relative to the rotation axis of the rotary table is 0.4 μm/200 mm. The mathematical models have been established for assessing planar and spatial straightness, flatness, roundness, cylindricity, and coaxality errors. By radial deviation measurement, the instrument can accurately measure form and position errors of such workpieces as shafts, round plates and sleeves of medium or small dimensions with the tolerance grades mostly used in industry.

Abstract: The performances of the precision machine tool will be influenced by its thermal characteristics seriously, and accurately predict the thermal characteristic of the key component of the machine tool is helpful to improve the design level. The headstock of a high precision CNC lathes has been regarded as the research objects, and the thermal properties and its influence on the performance of the machine tool are studied. Finite element analysis model of the headstock has been constructed, and the simulation calculations of the steady temperature field distribution and thermal equilibrium time of the headstock are calculated, and then the analysis to identify the thermal deformation trends of the spindle assembly and the heat distortion of the headstock are also been done. Some of the key factors that have significant influence on the thermal characteristic of the high precision machine tools are also studied. The analysis reveals that the performances of the machine tool will be influenced by the hot asymmetric, the study lays a foundation for the optimization design and thermal error compensation of the spindle assembly.

Abstract: The dynamic tilting of high-precision turntable has a very significant impact on the parameters of measurement and processing during the operation.In order to achieve long-term stability and control the turntable’s dynamic tilting angle at the second level, only improving the mechanical precision of the turntable is not realistic, and it may greatly enhance the cost of the turntable. A precision turntable dynamic tilting test method based on laser and CCD technology is put forward in this paper. The system uses laser as the light source, and uses CCD image sensor to receive the reflected signal of the turntable. According to the amount movement of the laser spot on the CCD target surface and the corresponding geometric relationships, we can measure the inclination error of the turntable. During debugging analysis and practical application, it proves that the system can achieve differentiate accuracy at the second level and meet the needs of online measurement.

Abstract: During deep penetration laser welding, changes in the metal vapor plume contain information about the stability of welding process. A high-speed camera was used to online monitor the welding process in order to detect the laser welding defects. A color segmentation clustering algorithm based on HSI color space was proposed for processing the recorded welding sequences. The effectiveness of algorithms based on different model is discussed, welding experimental results showed that the proposed algorithm could achieve better image segmentation, and it highlighted the edge of the metal vapor details in the image.