Applied Mechanics and Materials Vols. 687-691

Abstract: The wheel loader will release a lot of energy in the process of reducing the speed and braking. In the paper it introduced the types and features of the loader hydraulic hybrid system, analyzed configuration, energy saving scheme and working state of the loader parallel hydraulic hybrid system. The results show that the parallel hydraulic hybrid system is applied to the loader, not only it can efficiently recovery braking energy, but also it can improve the dynamic performance of the loader, so the engine can work in the optimal fuel economy area, improve fuel economy.

Abstract: The vehicular LNG(Liquefied Natural Gas) tank is a key component in the land transportation of-163°C LNG. The cryo-insulation performance of vehicular tank directly affects the security of LNG transport greatly. Based on a 40m³ vehicular LNG tank, a structural design of the vehicular LNG tank is completed, which includes its body,nozzles,heat-insulating layer,sealing devices,saddles and so on. With the safety requirements of less than 2% LNG evaporation rate, the leakage heat of LNG tank is analyzed completely. Then, a heat-insulating layer outside of LNG tank is completed with thermal design. Finally, with thermal software, the effectiveness of heat-insulating layer is proved.

Abstract: This paper attempts to use a simple and practical method based on the finite element theory for the optimal structural design of machine tool bed. The higher is the natural frequency of structure, the better are static and dynamic structural stiffness. Dynamics finite element model of CA6136 machine tool bed has been established with the finite element analytic technique in order to improve the dynamic characteristics. Then, two improved bed design schemes based on unit structure (US) are presented and analyzed by comparison using natural frequency and the total mass of structure as target. The simulation results indicate that the method is simple, effective and feasible. The method also can be applied to other dynamic structural design.

Abstract: Brushless DC Motor is a kind of a new motor which commutation signals replaces traditional motor mechanical structure with electronic signals. Square wave brushless DC motor can be divided into sensor motor and sensorless motor. Position sensor will increase system cost, motor size and maintenance difficulty, which bring about limitation and limits to promote its application in all areas. This project designs sensorless BLDC Motor control system with the core of the stm32 micro-controller and uses Back-EMF zero-crossing detection method. In the system designing software control algorithm, drawing schematic diagram of hardware and making PCB board have been completed dependently. The experimental results show that the system can well realize the starting and running of sensorless BLDC Motor control system, and have a good measure of protection.

Abstract: Most of hollow plastic products and plastic containers are blow molded In life and chemical transport industry, Extrusion system referred to as "heart" in a hollow blow molding equipment. Hollow extrusion blow molding processing of convenience, plastic products are widely used, and people's emphasis on resource utilization puts forward higher requirements for extrusion blow molding, In view of the hollow blow molding equipment large output, high efficiency and low energy consumption requirements, the development of extrusion equipment for the design and optimization.

Abstract: The human skeleton is a mechanical device that people can wear. It put the human intelligence and the robot physical together, relying on human intelligence to control the robot. It is a man-machine system to finish by people's own ability which is unable to complete tasks by robot alone. This paper studies the inherent law and movement mechanics of human body load walking principle. The purpose is to realize the human skeletons wearing comfort and walking stability, and improve the accuracy of the body weight. Analysis of the effect of load on gait parameters provided the necessary theoretical basis for the design of human bones.

Abstract: In this paper, based on the analysis of load-sensing principles, load-sensing pump mathematical model is derived, using the software AMESim to establish the physical model is intuitive, and conducts the simulation research, the dynamic operation curve. Research has shown that: load sensing valve spring stiffness, spool, spool diameter opening shape and quality response to dynamic load sensing pump will have a significant impact, which has a certain reference value for designing and using load sensing pump.

Abstract: Magnetic rotary encoder can be used to detect the rotor position of PMSM, in order to realize vector control of PMSM. An initial positioning method on magnetic rotary encoder based on open loop control system was presented to calculate absolute difference of average through setting Rotor position angle on multi point.Experimental results show that the method was simple and suitable to measure rotor angle exactly and easily.

Abstract: In order to evaluate the performance of regenerative heater comprehensively and scientifically, the fuzzy comprehensive evaluation model of regenerative heater is proposed on the basis of fuzzy mathematic theory as well as the relevant background knowledge of the problem. In the fist-level fuzzy comprehensive evaluation model, the evaluation indicator system was established taking the influence of the turbine load into consideration. The definition of “excellence degree” was given to show the relative approach degree between the quantitative indicator and the excellent indicator. Membership functions of fuzzy evaluation set were constructed based on the excellence degree. Knowledge in terms of twenty experts’ experience and historical data was used to determine the indicator weight set. In the second-level indicator fuzzy comprehensive evaluation model, four composition operator models were selected to conduct the fist-level evaluation. The proposed model turns out to be feasible and effective by three typical load conditions.

Abstract: To improve the controllability and maneuverability, airship is usually designed as static instability. But the airship is vulnerable to sudden wind interference in its ascent, resulting in divergent pitching motion. A new aerodynamic shape was put forward which added a inflatable aerodynamic-lift wing at backward of the airship hull. With the method of Computational Fluid Dynamics (CFD), aerodynamic characteristics and longitudinal static stability of the conventional airship and new winged airship were comparative investigated. It can be concluded that the new winged airship was longitudinal stable whereas the conventional airship was instable. It can be applied for restraining the sudden wind interference for airship in ascent.