Applied Mechanics and Materials Vols. 130-134

Abstract: Helicopter is a typical MIMO system including the properties of non-stability, strong coupling, uncertainty. Firstly, a robust internal loop ACAH controller is designed and analyzed to ensure decoupling and robustness on each channel by the robust H-infinite loop shaping. Secondly, the external loop is designed using the classical PID method on the base of decoupling internal loop. Both loops contain the part of anti-windup. The simulation results of the prototype model demonstrate that in both time and frequency domain, the performance of the controller meets the design requirement with a comparative simple structure. The results can also prove that it has some effect against to the model perturbation and achieve LEVEL1 of ADS-33E-PRF.

Abstract: A simulation model of dynamic & flexible scheduling about the large-sized components producing workshop was built by using the cellular automata according to both sides’ characteristics. The scheduling system can be divided into 4 parts: work station, buffer, work piece, and scheduling rules. Work station and buffer were viewed as fixed grid nodes, work piece as moving particles, scheduling rules as the local self-evolution rules which include station choosing rule, work piece sequencing rule and task activating rule. Model simulate the job scheduling of a certain generator components producing factory workshop.

Abstract: ZnO has recently attracted considerable attention due to its favorable properties such as the wider band gap (3.37eV) at room temperature, the large binding energy of excitons (60meV). These good photoelectric and piezoelectric properties [1-4] cause it has immensity space for developing at surface acoustic wave devices, light emitting diodes (LEDs) [5] , photodetectors [6], gas sensor and solar cells [7] etc. MgZnO has many similar properties to ZnO. Furthermore, the band gap of MgZnO is 3.3-4.0eV [9] due to the wider band gap of MgO (7.7eV [8]). In this paper, we report the characteristic of Mg_xZn_1-xO films which were grown on c-plane sapphire with different thickness-ZnO buffer layers by MOCVD. By investigating the surface morphology, structural and optical properties, some dependences between properties of MgZnO films and the thicknesses of ZnO buffer layers can be found.

Abstract: A New real-time position and orientation tracking system for endoscopy is described. Three coils sequentiallyfed with current comprise the excitation source which will produce magnetic field. According to Biot-Savart-Laplace law, flux intensity data detected by three-axis magnetic sensor could be interpreted into information that will reflect the sensor's specific position, thus realizing the position determination. Also, data detected by the magnetic sensor and gravity sensor changes in connection with the spatial angles. By researching the change law between the two, spatial angles of the sensor is calculated, thus realizing orientation determination. It is shown errors in position determination is,errors in orientation determination is , the tracking frequency of the system is 10 Hz.

Abstract: Macro-micro dual-driven technique is an effective method to realize motion control of long-stroke and high-precision. The basic line is that micro feed stage compensates the error of macro feed stage measured by displacement sensor in order to decrease system error and improve positioning precision. This paper sets up two-axis macro-micro dual-driven system consisting of planar axis motor and piezoelectric ceramics actuator. The planar axis motor realizes coarse feed and piezoelectric ceramics compensates motion error. Flexure hinge is adopted as micro transmission mechanism to avoid noize, friction and gap. By adopting Digital Signal Processor as the controller, the compensation can be seen as synchronous. The experimental result shows the error of this system is under 200nm.

Abstract: An automatic measuring system based on the principle of non-contact capacitive sensor for inner diameter measurement of the coaxial transmission line outer conductor (diameter:) is introduced in this paper. Through the theoretical analysis, the system also can be used to measure inner diameter of inclined holes. In this system, accuracy positioning is realized in the way that stepping motors cooperate with gratings; accuracy centering is realized by vision CCD system and X-Y accurate slide. Software VC++ is developed for the automatic measuring system. The function of accuracy centering, sensor calibration, automatic inner diameter measurement, data collection, data processing and data analysis are realized by software.

Abstract: Personal and consumer electronics products facilitate and enrich our life, however consume lots of energy and resources. Synthetically considering a product's quality, functions, cost, schedule and user experiences, this paper systematically discusses how to design energy saving product and lists some methods and actions in practice from three aspects, hardware design, user interface design and software design. It is of guidance and reference for energy saving design of personal and consumer electronics products on certain aspects.

Abstract: Based on the analysis of forces on the circuit breaker operator and its component in any instant position during the slow closing work process, this essay applies Friction Circle Theory, Disconnecting Pairs Method and Balance Conditions of Shared Surface Power System and calculates the allowed values of contact pressure in any instant position. This essay also reaches a conclusion that in any instant position in the process of operating device slow closing work, the real value of contact pressures should be less than the allowed value of contact pressure on this position to guarantee that the slow closing work process of the circuit breaker operator is qualified.

Abstract: In order to reduce vibration and noise of the compressor used in small and medium-sized refrigeration unit, this paper designs different vibration isolating systems and carries out experiment of isolation performance evaluation based on LMS Test. Lab Signature software. The comparison results of four different vibration isolating systems show that the peak values of vibration velocity response in each system mainly appear at 25Hz, 50Hz, 75Hz and 100Hz, and the maximum velocity does not exceed 22mm/s which is less than the maximum allowed by the national standard^[1]. And the Vibration Level Difference (VLD) is taken as evaluation criteria for isolating vibration, that of single-layer vibration isolating system is within 10-20dB, and that of double-layer vibration isolating system is within 20-35dB. Furthermore with the increase of middle-mass, the VLD has a clear upward trend.

Abstract: This paper mainly researches the problem that enterprises select equipment resource in manufacturing resources sharing system. There are many influencing factors and some are uncertain or unqualified in the selection, therefore this paper using AHP and grey correlation analysis to evaluate and select. Firstly, the selection index system of equipment resource according to AHP is established, and then selection model based on multi-hierarchical grey correlation analysis is constructed. Applying this model to help enterprise select equipment can avoid errors resulted from human objective cognition difference and equalitarianism. The select result is more scientific and reasonable, and more in line with the enterprise requirements.