Design and application of a new kind of rolling coupling

Based on Hertz theory of elastic contact and the design theory of ball bearings, a new type of rolling coupling was designed. The two halves of the rolling coupling can be moved relatively by a small axial force when a great moment is exerted on it. The rolling coupling was used to connect the principal axis and the decelerator of continuous extrusion machine and it can greatly decrease the harmful axial forces on the continuous machine. The engineering formulas for the contact stress and distance of apporach of the rolling elements were deduced and the method for designing the rolling couplings was proposed. The formulas for the forces exerted on the rolling element were verified by the experiment.     

Performance of a 60 F carbon nanotubes-based supercapacitor for hybrid power sources

A supercapacitor based on charge storage at the interface between a high surface area carbon nanotube electrode and a Li-ClO4/PC electrolyte was assembled. The performance of the capacitor depends on not only the material used in the cell but also the construction of the cell. From a constant charge-discharge test, the capacitance of 60 F was obtained. The performance of the power capacitor for pulse power sources was described. The specific energy (0.8 W·h·kg-1) and the specific power (0.75 kW·kg-1) of the power supercapacitor were demonstrated with a cell of the maximum operating voltage of 2.5 V. A hybrid power source consisting of a lithium ionic battery and the 60 F supercapacitor was demonstrated to power successfully a simulated power load encountered in GSM portable communication equipment. The addition of the supercapacitor to the power train of a cellular phone results in significantly more energy from the battery being used by the load. The experiments indicate that more than 33.8% energy i     

Design of a New Type of Distribution Valve for Hydraulic Breaker and Analysis of Energy Consumption

Energy consumed by distribution valves causes an energy loss for the output energy of hydraulic breakers, which has a significant influence on its efficiency. A new type of distribution valve used for hydraulic breakers, designed to reduce energy consumption, is analyzed on the basis of the operating principle and energy loss of the current distribution valve. The new distribution valve adopts a cone valve and the optimization technique of unequal open degree for the valve port. Theoretical calculations and analyses have proven that the new distribution valve can reduce energy loss by 9.0127J, or energy consumption by 31%, during an impact cycle and the efficiency of the hydraulic breaker can be raised by 4.5%. It has the following characteristics： little leakage, little pressure loss and low energy consumption.     

Design of a Radar Signal Simulator Based on Virtex-Ⅱ Series FPGA

A simulation method to simulate the pseudorandom code P.M PP radar's echo signal is proposed that makes use of the pre-generated Doppler simulation data, according to the relative movement parameter of the radar and the target. It resolves the problem of the high precision distance simulation and the high speed digital shift phase. At the same time, the radar dynamic digital video frequency target signal simulator is designed. Simulation results of the critical unit and the output waveform are given. The result of the test satisfies the system's request.     

Design of a Radar Signal Simulator Based on Virtex-Ⅱ Series FPGA

The si mulation of radar echo is a dynamic pro-cess,including generation,transmission and process-ing of the radar echo.Many techniques,such assemiconductor,computer and signal processing areusedin the process of si mulation.The si mulation ofradar echo is a combination of the digital si mulationtechnique and the radar technique.Its basic tech-niques include the computer and signal processingtechniques.Its object is to test the algorithmand thequality of theintegrated system,as well as to eval…     

Design of a Mobile Mechanism for Missing Miner Search Robots in Underground Mines

1 Introduction It is important to search and locate missing min- ers promptly, rapidly and accurately after disasters occur in underground coal mines[1–2]. The missing miner searching robot (MMSR)[3] for underground mines is an autonomous mobile robot used for searching and locating missing miners and detecting the surrounding parameters of the dangerous under- ground coal mine environment after mine disasters. In areas where mine rescue team members cannot go, MMSR can replace rescuers to…     

Design and Implementation of a Network Management System Based on Mobile RMON Agent

To improve the scalability of RMON-based network management, the concept of Mobile RMON Agent （MRA） was presented by combining the mobile agent technology with RMON. Then an MRA-based Network Management System （MRANMS） was designed and implemented. RMON functions were achieved by programming the mobile agent to make it capture and analyze packets locally. The experimental result on the Grasshopper platform indicates that MRA as a mobile agent can migrate to another subnet and calculate a RMON MIB value and TrafficMatrix in a subnet with 29 hosts. Furthermore, the behavior of MRA can be customized to achieve new RMON functions, such as the statistics of hostTable in RMON MIB. It can be concluded that MRANMS is based on the mode of distribution, and besides the compatibility with standard RMON, the system possesses scalability of management function.     

Robowler:Design and development of a cricket bowling machine ensuring ball seam position

The art of cricket bowling is complex and arduous owing to the run-up and ball release time energy requirement to achieve speed and variations. Therefore, human bowlers cannot bowl for extended periods and numerous mechanical bowling machines have been built to help batsmen improve their skills during practice sessions. However, most of these existing machines are designed for spherical balls ignoring the distinguishing physical feature of a cricket ball： the raised equatorial seam, which makes it less of a sphere. The bowlers are known to often benefit from this seam in their pursuit to taking the batsmen＇s wicket by imparting swing, spin and bounce variations along-with other bowling variables. This lack of the seam consideration creates a void between human and mechanical bowling. In this work, we present design and development of an automatic bowling machine termed as ROBOWLER to make mechanical bowling more realistic. This machine ensures ball seam position as well as fulfills other constraints. Ball pitching and seam position accuracy results underscore the suitability of this design to enhance the capabilities of mechanical bowling.     

Design and Development of a Vector Control System of Induction Motor Based on Dual CPU for Electric Vehicle

A vector control system for electric vehicle (EV) induction motor drive system is designed and devel-oped. Its hardware system based on dual CPU( microcomputer 80C196KC and DSP TMS320F2407) is imple-mented. The fundamental mathematics equations of induction motor in the general synchronously rotating refer-ence frame (M-T frame) used for vector control are achieved by coordinate transformation. Rotor flux equation and torque equation are deduced. According to these equations, an induction motor mathematical model and rotor flux observer model are built separately. The rotor flux field-oriented vector control method is implemented based on these models in system software, some of the simulation results with Matab/Simulink are given. The simula-tion results show that the vector control system for EV induction motor drive system has better static and dynamic performance, and the rotor flux field-oriented vector control method was practically verified.     

LMI Approach to Robust H∞/H2 Controller Design with Regional Poles Constraint of a Pump-Motor System

The time domain guideposts requirements of a pump-motor system is transferred into a series of constraints which express the robust performance upper bound and regional poles limits of the closed loop system. Then the servo system control problem is transferred into the problem of robust performance optimizing under regional poles constrains described by linear matrix inequality (LMI). These LMIs are easy to solve through the Matlab LMI-toolbox. Simulations indicate that the controller has excellent dynamic, static and disturbance rejection performance, and the control system is robust and has perfect H2 performance to the bounded external torque disturbance.     

Design of a d_（33）-mode piezocomposite electricity generating element and its application to bridge monitoring

The piezoelectric effect is used in sensing applications such as in force and displacement sensors.However,the brittleness and low performance of piezoceramic lead zirconate titanate（PZT） often impede its applicability in civil structures which are subjected to large loads.The concept of a piezocomposite electricity generating element（PCGE） has been proposed for improving the electricity generation performance and overcoming the brittleness of piezoceramic wafers.The post-curing residual stress in the PZT layer constitutes a main reason for the PCGE＇s enhanced performance,and the outer epoxy-based composites protect the brittle PZT layer.A d33-mode PCGE designed for bridge monitoring application was inserted in a bridge bearing to provide a permanent and simple weigh-in-motion system.The designed PCGEs were tested through a series of tests including fatigue and dynamic tests to verify their applicability for monitoring purposes in a bridge structure.A simple beam example was presented to show the applicability of the proposed bridge bearing equipped with the PCGE for adequately measuring the traffic loads.     

LMI Approach to Robust H∞/H2 Controller Design with Regional Poles Constraint of a Pump-Motor System

Whenfacing withthe practical servosystemcon-trol problem,the control systemis often required tomeet many performance indexes which include ti medomain,frequency domainand H∞/H2.Theseindex-es have explicit purpose and appliedsituation.For ex-ample,the H∞normbetween disturbance and outputrepresents the capability of noise-i mmune,the smallerthe H∞normis,the more excellent stiffness the sys-temhas.And the square of H2norm between inputand output is equal to the energy of the systempulserespo…     

Research on Two Types of Buffer Zone Impact on Surrounding Office Space Environment in Winter in Cold Climate Zone—a Fieldwork in Architectural Design Institute Building of Tsinghua University, Beijing

Building buffer zone space is not only one of essential approaches for better mental quality of interior building space, but also an important factor that may influence interior thermal comfort and energy consumption. This study aims to analyze regulative advantages of buffer zone to the surrounding functional spaces. Based on a fieldwork test in a typical office building in cold climate zone in Beijing, China, the monitor data show interior physical performance in the Winter. The research selects two types of different buffer zones in the same building. One is a south？faced greenhouse which has large dimension with plenty of vegetation, and the other is a simple atrium in the middle of five floor building with mount of skylights. The factors and their influence to surrounding functional spaces and the whole building are found out from the comparisons of collected data by floor to floor monitor test on both buffer zones at the same time. The comparisons of two types of buffer zones conclude that the greenhouse is more effective to air quality regulation but not so clearly well？performed to thermal buffering as expected due to the dominate active central heating in the Winter. This fieldwork test results for building performance can be helpful for both architects and engineers in the early phase of sustainable design.