Applied Mechanics and Materials Vols. 249-250

Abstract: Model based systems engineering (MBSE) is becoming a promising approach for the system-level design of complex mechatronics. And several MBSE tools are developed to conduct system modeling. However, the system design cannot be optimized in current MBSE tools. In this study, an approach is presented to conduct the task. A set of optimization stereotype is defined at first which is used to formalize the optimization model based on the system design model. Then the design parameters and their relationships applied optimization stereotypes are extracted and transferred to construct the tool-dependent optimization model. Finally, the optimization model is solved and the results are given back and then modify the corresponding system model automatically. In this paper, MagicDraw is used to model the whole system whereas Matlab optimizer is used for optimization. The combustion engine is chosen as the example to illustrate the proposed approach.

Abstract: In this study, a meta-model based method is proposed for automatic generation of STEP AP 203 file for mechanical part of the mechatronic system from the SysML model. System modeling technology in SysML is firstly presented and then the model of EXPRESS language is employed to transfer the information from SysML through the model transformation method. Based on the information parsed from the resulting EXPRESS model, the STEP file is finally generated by creating the B_REP model in STEP AP 203 standard. The proposed method is illustrated with a case study named as inverted pendulum system (IPS).

Abstract: For the unsatisfactory of the traditional linear control methods, on the basis of the mathematical model of PMSM, a combination of backstepping control method based on the Lyapunov function and adaptive control method is used in the speed control system of PMSM. A method of estimating the rotor position and speed based in extended Kalman filter (EKF) for PMSM is proposed. A simulation model of PMSM using the designed adaptive backstepping controller with EKF is built. The results of simulation using the control method show the preferably dynamic and stable-static performance of the system, and prove its effectiveness.

Abstract: The conservatism of asymptotic stability conditions is considered in terms of linear matrix inequalities for time-varying delay systems. The conservative index is defined to evaluate the conservativeness for both delay-dependent and delay-independent stability conditions. The general results on performance analysis are presented based on descriptor system approach. The conservativeness index is defined for time-varying delay system. The optimization approach is given to obtain the upper delay and rational performances for the state-feedback controller of time-delay systems. Experimental results verify the effectiveness of the new method.

Abstract: Particle swarm optimization (PSO) is a well-known population-based searching algorithm to solving optimization problems. This paper aims at identifying significant control factors for PSO to solving the design optimization problem of a four-bar linkage for path generation. Control factors considered herein are inertial weight, acceleration coefficients, breeding operation, and the number of population. A full factorial design of experiments is used to construct a set of experiments. Experimental results are analyzed with the analysis of variance method. According to the results obtained in this paper, breeding operation and the interaction between breeding operation and acceleration coefficients are significant. Inertial weight, acceleration coefficients, the number of population, and the other interactions are not significant. For the design optimization problem discussed herein, it is suggested to adopt breeding operation strategy and apply constant acceleration coefficients to increase significantly PSO’s performance and robustness. Type of inertial weight and the number of population do not affect PSO’s performance and robustness significantly.

Abstract: Based on the fact that a large number of timing controllers are needed in the applications like sequential logic control and programmable controller, this paper proposed a PLC timer system based on ARM+FPGA, in which ARM is used to execute user program while FPGA is used for timer operation in parallel. The FPGA timer module consists of timer controller, timer dynamic parameters and soft contact state register, the timer controller carries out counter operation for timing unit every 1ms, then results from timing operation would be saved in timer parameter list of a dual port RAM, when controller commands need to be executed via PLC, the timer will be used as a regular memory unit for W/R operation, thus no executing time of PLC program would be spared basically, which can well meet the system requirements where large number of controllers are needed. Simultaneously, principles of system composition, timing operation control and timing operation flow are all introduced followed by which a field test is also carried out for testament of the designed timer system.

Abstract: Disappearing mould casting is a new accurately processes with nearly free margin and precision forming, in which is no modulus, no parting, no sand core, so the casting without splash, burr and taper angle. It can improve the dimensional accuracy of the core portfolio for complex surface of the key compose of the disappearing mould. It has completed the design and manufacturing of these by the three-dimensional CAD/CAM technology, and obtains a series of effective methods and experience for the development of the products. The researched results have important directive to production practices for the design and machining process for the expendable pattern casting.

Abstract: In this paper, we design the source precoding matrix and the relay amplifying matrix of a multiuser multiple-input multiple-output (MIMO) non-regenerative relay system. Different from the other algorithms, we first introduce a new model with new unknown but to be designed variables. Then we proposed an iterative algorithm to get the source precoding matrix and the relay amplifying matrix to optimize the system performance. The simulation results show that the proposed design algorithms can improve mean square error (MSE) performance.

Abstract: In order to cultivate the students with the engineer quality, the typical product cases guided engineering graphics teaching reform for communication engineering major is performed. The content of the course is decomposed into four parts and merged into product. Student-led, teacher-guide classroom atmosphere is established and task guided examination method is carried out. Results show that the new teaching reform is welcome and good effect is achieved.

Abstract: As technology grows, the automation technologies integrated into the realm we live, and it continuously to provide people more comfortable and efficient environment. This study systematically applies the TRIZ theory to find out the problems in home automation development. We use contradiction matrix and 76 standard solutions provided by TRIZ to filter out the possible development of these home automation issues in the future. In this research, we conclude the factors of home automation technologies as follows: (1) the efficiency of operating environment; (2) the installation and maintenance of Internet; (3) the security and privacy of Internet. After analyzing through the directions of TRIZ innovation principles and standard solutions, this study proposes the development trend of each sub-problem.