Applied Mechanics and Materials Vols. 105-107

Abstract: To achieve the tracing control of a three-links spatial robot, a backstepping fuzzy sliding mode controller based on variable rate reaching law is proposed in this paper. The sliding mode controller is designed by means of backstepping way. To reduce the adjustment time, a fuzzy controller is designed to adjust the slope of sliding mode surface. To diminish the chattering of traditional sliding mode control, the variable rate reaching law is proposed. The variable rate reaching law is composed of the distance from current point to sliding mode surface in phase plane. The simulation studies for the tracking control of a three-links spatial robot have been carried out. Simulation results show the validity of the proposed control scheme.

Abstract: In order to meet the development demands for high-speed and high-precision of Computer Numerical Control (CNC) machine tools, the equipped CNC systems begin to employ the technical route of software hardening. Making full use of the advanced performance of Large Scale Integrated Circuits (LSIC), this paper puts forward using Field Programmable Gates Array (FPGA) for the functional modules of CNC system, which is called Intelligent Software Hardening Chip (ISHC). The CNC system architecture with high performance is constructed based on the open system thought and ISHCs. The corresponding programs can be designed with Very high speed integrate circuit Hardware Description Language (VHDL) and downloaded into the FPGA. These hardening modules, including the arithmetic module, contour interpolation module, position control module and so on, demonstrate that the proposed schemes are reasonable and feasibility.

Abstract: Airport crash fire vehicle simulator is an important device that is used in training of the airport firefighters, which has advantage of safe, energy saving and decreasing training cost. Sound system is an important part of airport crash fire vehicle simulator, which provides voice message to training personnel, which can make training personnel have immersed sense. Based on the principles of sound source position to analyze the different physical structure of the human body (head, torso, pinna) the impact of sound localization, the establishment of head-related transfer function model, using the model of the sound source, filtering, delay processing, and virtual sound source. And we have tested and verified with listening experiment.

Abstract: This paper mainly used two different grey models to predict the numbers of candidates of applying for the college entrance examination. We firstly introduced the conception of GM (1,1,D) and GM (1,1,C), briefly explained the difference between them from the aspect of theory, and then put them into the application of predicting the situation of variance of candidates for college entrance examination. Finally, we analyzed the reasons for this change and countermeasures. Compared to the application of numbers of candidates for college entrance examination by using two grey prediction models, this paper gives an effective method of data analysis, and provides technical information for the relevant decision-making departments. This paper set a good example for the application of selecting the correct grey model to address specific problems.朗读 显示对应的拉丁字符的拼音 字典

Abstract: The steel strand cables can effectively stand for the horizontal wind load, enhance the lateral stiffness of the lifting stand, reduce the horizontal displacement of the tower and improve the overall stability. Based on a cable-truss mixed finite element model, in which the cables are simulated via the equivalent elastic modulus method, cable’s parameters, including the tilt angle, initial stress and layout of cables are analyzed. With the increasing of initial stress of cables, the lateral stiffness and overall stabalitily of the structure is improved greatly. And a certain range of tilt angle can effectively enhance the overall mechanical performances, insufficient or overlarge tilt angle are disadvantage of the overall structural strength and stability.

Abstract: Data acquisition in fields, especially yield data acquisition, is an important step in precision agriculture.To obtain the yield information, a grain mass flow condition monitoring system is developed. which consists of impulse-type grain mass flow sensor, grain mass flow condition monitor, CPR transmitter and power supply component. The grain mass flow condition monitor collects data from grain mass flow sensor;displays and stores them after processing. On the basis of test rig experiments with wheat, wheat field experiments are finished in June 2010 .The experimental results show that the accuracy of this monitor syterm is within 3% in test rig experiments and within 5% in field experiments while the grain flow rate is 0~ 2 .5kg / s, which met the precision agriculture production accuracy.

Abstract: This paper analyzes the importance of rock bolting in coal mining, and the difficult of using rock bolting in breakthough with the affect of mining, adopt hydraulic fracturing and coal-rock mass strength test methods to test the seam stress and rock strength. Make the numerical simulation of break though bolting solutions in coal mine roadway by using FLAC3D software, simulate the different distributions of pre-stressed in coal-rock with three situations, the same raw distance but different space, the same space but different raw distance, impose different preload on the roof anchor in the rock bolting of mine roadway breakthough. Then determine a reasonable bolting solution of coal mine roadway according to the case of prestressed in coal-rock.

Abstract: This paper aims at exploring a new parallel machine as a configuration integration, and developing this new configuration into a series. The moving platform of this parallel machine (spindle) replaces the swivel ball joints with joint rings. In the machine processing, the rigidity of the spindle parts can be enhanced. The layer of joint rings will increase holding points of spindle components and reduce singularity of the parallel machine. The comprehensive method of machine will be used in this paper which is based on the azimuthal characteristic. Each chain of the machine will be splitted into a single opened chain for research, analyzing the azimuthal characteristic of each kinematic pair. A union method is also used to work out the motion output equation of each chain. Different chain combination and intersection method will be applied on the basis of the verification of a 5-strut parallel machine to build the parallel machine of four degrees of freedom with joint rings.

Abstract: This paper describes a prototype system based on floating taxi for traffic condition identification. The system consists of in-vehicle hardware units placed in floating taxi and backstage database that process all data send from the report units. The communication between the taxi and the database center is based on a very compact wireless communication protocol. The taxi sample size is decided by the variables: section traffic information update cycle, data sampling interval, section covering ratio. The test in a road section showed that the system is operational which could offer useful reference for urban traffic management and resident trips decision.

Abstract: Quantitative dimensional metrologies of Nano/microstructures are increasingly demanded following the rapid developments in, for instance, semiconductor and precision engineering industry, microsystem technology and materials science. In the recent years, coordinate measuring machines (CMMs) have become versatile and widespread metrology tools. Probing system is an important component of a CMM. A probing system based on a high accurate positioning transducer is crucial for micro and nano metrology. This paper presents a probing system based on a variable micro-capacitive transducer which has advantages of simple structure, low cost, high sensitivity, overload ability, excellent dynamic response characteristics, etc. The structure of variable capacitor was designed and optimized by means of finite element method (FEM), and fabricated by surface micromachining technology.