Abstract: To avoid the instability of the tension control in the continuous transmission process, a constant speed control system is designed and used in winding mechanism for composite films. Combining the mathematical model and the ratio speed control method, a system control algorithm is proposed. Results show that the system has the excellent robustness and the rapid speed response which meet the requirements of high speed constant tension control in the packaging industry. In order to improve the dynamic performance including fast response and non-overshoot, gain control and variable integration time constant control is used. Further, feed forward control method and adaptive control method is utilized to stabilize the composite films tension.
Abstract: To decrease the thermal error in the machining of high speed machine tools, a new design idea based on the cellular metal structures was proposed. With forced convection in cellular metals, the heat generated in machining will be dissipated and the machining precision can be guaranteed. The thermal property of machine slides using 2D rectangle cellular structures was studied with theoretical analyses and numerical simulation. The theoretical predictions are in good agreement with the finite element simulation results. The overall heat transfer coefficient and the thermal performance were acquired with the volume-averaging method and the relationships between the cellular porosity, cellular sizes and the thermal performance were discussed. The analyzed results show that the maximum thermal performance can be got when the cellular porosity equals about 0.85 and with the increase of cellular sizes, the thermal performance decreases.
Abstract: The paper analyzed arc suppression coil with magnetic bias compensating system with linear system rules. The nonlinear and time-variable performances are considered during model building process. In order to optimize control effect, the paper adopted improved BP neural network PID controller with closed loop control method. Improve BP neural network with the combination of the two strategies, adding momentum method and adaptive learning rate adjustment, can not only effectively suppress the network appearing local minimum but also good to shorten learning time and improve stability of the network furthermore. The results of simulation and experiments indicate that arc suppression coil based on improved neural network with PID control method can quickly and accurately control the compensating capacitive current to an expected value and it has strong robustness. The paper also provided core controller with software and hardware designing scheme based on STM32 microcontroller.
Abstract: The larger variation of the construction and performance of the low-carbon steel joints was caused by the high temperature of the puddle welding of the joint. Therefore, the braze welding rather than the puddle welding was applied to the welding production of low-carbon steel. The 08 steel parts were joined in a furnace using pure copper solder paste as brazing filler metal. According to the obtained results, the ideal technical parameters are as follow: brazing temperature: 1100-1150°C; holding time: 5-10min; joint clearance: 0.03-0.05mm.
Abstract: As one key technology of Rapid Tooling (RT), Indirect Nonmetal Rapid Tooling (INRT) has been used widely, so this paper analyzed the modeling process of INRT and concluded that the velocity of stirring and casting are key factors which affect products quality and production efficiency. In nature, just need to control the speeds of driving motors. In order to resolve problems of existing modeling equipments, such as strong dependency on operators experience and low control precision, this paper studied an intelligent controller model based on Fuzzy Wavelet Network (FWN) which integrated wavelet analysis and fuzzy neural network technologies. The structure and implementation algorithm of FWN are introduced in detail. After considering the advantages of Permanent Magnet Synchronous Motor (PMSM), the INRT equipments use it as driving motors. Because it is nonlinear, uncertain, coupled, sensitive and multivariable system, this paper made improvement on traditional IP controller, FWN acted as error compensator which can compensate for disturbance influence and trace expected speed in real time. The IP intelligent controller based on FWN can strengthen interference ability. The robustness of this control system has been verified by simulation experiment. This controller realized closed loop control of stirring and casting motor and improved the products quality and control precision of INRT.
Abstract: With the development of the CNC precision machining and the ultra-precision machining, machine tools error issue has became the most active research topics and concerned by more and more experts. In this paper, a rapid simulation software platform based on multi-body system theory and Matlab software for measurement and analysis geometric errors of CNC machine tool is presented, which includes the generation of simulated measurement data, data processing, error separation and error compensation etc. To verify the feasibility of the developed software, the sequential step diagonal vector measurement method has been analyzed. The experimental results show that after error compensation the machine performance is improved by 39%. It demonstrates that the sequential step diagonal vector measurement method could significantly improve the machine accuracy and the developed software platform is reliable. This platform is not only effective for step diagonal vector measurement method, but also can be applied to other measurements. Therefore, the software platform provides a fast, reliable and objective tool for machine error measurement and analysis.
Abstract: In view of the problem of convergence of positioning and inaccuracy of social functioning for a large number of local colleges and universities in our country, this paper draws lessons from Ernest Boyer’s new paradigm of scholarship and its enlightenment on the diversified development of scholarship in America’s local colleges and universities, re-examines the mission of local colleges and universities for the local services in our country, and puts forward suggestions on diversified development of scholarship for local colleges and universities.
Abstract: Wire Suspension is widely used in sensors, especially support the DVD actuator in each of side. The mechanics model of it can be regarded as cantilever beam. The dynamic model of the gear is established by FEM（Finite element method）and modal analyses of the wire suspension are investigated by ANSYS software.
Abstract: The marking system by laser shock wave (LSW) based on liquid crystal mask, which differs entirely from marking by laser ablation (or laser thermal effect), was established. Two-dimension (2D) nondestructive markings based on liquid crystal mask were prepared by LSW, and the distribution of residual stresses in laser-shocked region was measured and analyzed. The results showed that tensile residual stresses of sample surface were converted into compressive residual stresses by LSW, which is a nondestructive marking for aviation key parts.
Abstract: The means of classification of the NC machine tool malfunctions is the key basis on detecting malfunctions and processing malfunctions` s signal. By defining malfunction mechanism and malfunction mode, a series of new classifications are presented. According to malfunction mechanism, mechanical malfunction are damage malfunction, lubrication malfunction, and fit malfunction. According to malfunction mode, the noise malfunction can be classified as vibration malfunction mode, the heating malfunction can be classified as heating malfunction mode, and the bad motion malfunction can be classified as deformation malfunction mode. Conclusion is that damage malfunction of gear and bearing malfunction is the most frequent malfunction whose performance formation is noise. Another conclusion is that tooth surface fatigue is the familiar malfunction, and bearing malfunction is mainly caused by surface peeling. Based on these conclusions, the vibration model of the mechanical failure is established, which lays a foundation for dealing with the follow-up signal.