Applied Mechanics and Materials Vols. 380-384

Abstract: In this paper we apply multiprocessor system with controller and multi-channel technology to design a loom control system of multilayer and multi-channel. The electronic control system uses the idea of module design and regards the multiprocessor as the part, all control software and hardware design are all independent. Electric control system with high performance and precision consists of each control module, and has better scalability. Practice has proved that the electronic control of loom improves the efficiency, helps the manager to make decisions, contributes to the network management of loom and adapts to modern production.

Abstract: Spacecraft formation flying has higher performance, higher reliability and lower costs comparing to the traditional single spacecraft. So it becomes a research hotspot in the field of aerospace in China and abroad over the past decade. This paper focuses on the orbital maintenance control between the following spacecraft and the main spacecraft. On the basis of circular orbit or nearly circular orbit, this paper studied the relative motion of spacecraft formation flying based on the Hill equation without considering the influence of the perturbation factor, when the distance between spacecrafts is close. This paper used the generalized predictive control method to design a controller of spacecraft formation tracking. By using Matlab/Simulink, the simulation results showed that the spacecraft has a good orbit tracking capability and a strong anti-interference ability.

Abstract: Based on computer and PLC control technology, the control system for electron beam welder has been studied in this paper. By using PLC control technology to implement the intelligent control (IC) in welding process and adopting the high-frequency inverter technology, to realize the high-voltage interlock protection, the quality of electron beam current spot as well as the welding technology has been improved. Concerning the requirements on the technical and process, the design of computer communication and PLC application software demonstrate the feasibility of this method.

Abstract: Using of feedback linearization technique to solve the problem of traditional sliding mode control chattering. The fuzzy adaptive control and sliding mode variable structure was designed by combining a novel adaptive fuzzy sliding mode variable structure controller. Through fuzzy inference and the stability analysis based on Lyapunov function to obtain fuzzy control rules adaptive law and effective solution to the traditional sliding mode control of the need to determine the parameter perturbation and external interference supremum uncertainty. Simulation results show that this method has better stability and robustness.

Abstract: in this paper, a very low cost two-axis position servo system is developed. This system is controlled by DSP. We study the stability of the position servo control system. We use the PI control algorithm in our application. We achieved twice switching frequency by using PWM signals to share the switching dissipation ePWM module of the DSP. A numerical consideration is given. The simulation results demonstrate the stability of the proposed method.

Abstract: In 2011, Lee et al. analyzed the security weaknesses of Hsiang et al.s scheme and proposed a security dynamic ID-based multi-server remote user authentication scheme. They claimed that their protocol is secure and efficient. However, we observe that Lee et al.'s scheme is still vulnerable to stolen smart card attack, malicious server attack. To remedy these security weaknesses, we propose an improved dynamic ID-based remote user authentication scheme for multi-server environment. Besides, security analysis and performance analysis show that compared with other remote user authentication schemes, the proposed scheme is more secure and possesses lower computation cost. As a result, the proposed scheme seems to be more practical for users with portable mobile devices in multi-server environment.

Abstract: Based on the mathematical model analysis of the three-phase voltage source PWM rectifier under abc reference frame and dq reference frame in this paper, a kind of three-phase voltage source PWM rectifier feed-forward decoupling control strategy is proposed. Dynamic response of DC bus voltage for PWM rectifier is very important, because higher response means little DC bus capacitor. An adaptive PI controller for the DC bus voltage was designed in this paper in order to improve the dynamic response. The experimental results indicate that this control method has good steady-state performance and fast dynamic response. For the reason of its simple, this control method has certain practical value.

Abstract: A temperature rising control system and temperature maintaining control system were designed in according to time-variable and hysteretic nature of temperature change and limitation when traditional PID control deals with nonlinear systems. A new type of intelligent fuzzy controller combination of traditional PID control and fuzzy control was designed and applied in temperature maintaining control system. The simulation results show that the holding phase at elevated temperatures and temperature, the temperature curve has a high steady-state accuracy and dynamic performance in the period of temperature rising and maintaining, and the system and controller cause a better result.

Abstract: The large attitude maneuver is studied in this paper. The quarternion form attitude is appilied to avoid the singularity of dynamic equations, and sliding mode control law based on quarternion is desined. The spacecraft attitude dynamics and control model is builted using simulink, which was valided by simulation.

Abstract: An isolated three-level H-bridge high-capacity DC/DC converter is a good solution for transferring energy from middle-voltage network to low-voltage network. The transformer can be smaller and lighter with high working frequency, so phase shift Pulse-Width Modulation (PWM) is used by converter. The small signal model has been built by theoretical derivation and verified by simulation when the converter working on Continuous Conduction Mode (CCM) and Discontinuous Conduction Mode (DCM). The analyze results indicated that the mathematic models and dynamic properties were different when converter working in disparate mode. Therefore, the PI parameters of the controller can be hardly chosen to reach the excellent dynamic performance when the converter meets the large disturbance of mode change. That is, you can hardly find a group of PI parameters for converter working well in all load range. Aiming at it, A PI adaptive non-linear control strategy based on CCM/DCM fast identification has been proposed. The fast mode identification was based on inductor voltage characters, and the mode information wound send out in less than a switching period. So, the PI parameters can be instantaneous changed by mode signal to achieve the best dynamic property. The operation principle and analyze result of the control strategy is verified by the prototype at last.