Showing papers in "Journal of Mechanical & Electrical Engineering in 2011"

Application of μC/OS-II in digital welder control system

Abstract: Aiming at improving the stability and real-time characteristics of welding control system,a hardware control system based on digital signal processor(DSP) was designed.The μC/OS-II embedded real-time kernel was applied in the control system software design,and it was transplanted to TMS320LF2407A.According to the system structure and functional requirements of the control system,welding application tasks were created and intertask communications were designed.Experiment results prove that this control system has high reliability.

Review on research status and application of wireless sensor networks

Abstract: Aiming at the latest development of the sensor,microprocessor and wireless communication technology,in order to intensive study the key technology of wireless sensor networks,the domestic and overseas research status of wireless sensor networks was analyzed on the basis of introducing the development history of the wireless sensor networks as well as system architecture.And the application of wireless sensor networks was disscussed in following fields,military,medical treatment and public health,environmental monitoring,smart home and so on.And the hot issues of the wireless sensor networks were also elaborated.The results indicate that the wireless sensor networks have been developing toward low cost,low energy consumption,intellectualization which has a certain reference value for carrying out relevant research.

Binocular vision based locating system for underwater inspection

Abstract: A new binocular stereo vision locating system was designed for the guidance of the manipulator on a remotely operated vehicle(ROV).In order to adapt the complex underwater environment,a sealing structure for the camera,a method of underwater calibration and a new method of object locating based on front parallel plane transformation were designed.Experiment results show the accuracy and stability of the underwater locating system,the locating error of which can be kept within 3%.

sEMG signal analysis method and its application in rehabilitation medicine

Abstract: There are various surface electromyography(sEMG) analysis methods,as time domain,frequency domain,parameters model,time-frequency domain,nonlinear dynamics domain and so onAiming at choosing method to analysis sEMG,after analyzing various analysis methods,the features,advantages and disadvantages,use case of those methods were comparedThe results indicate that every method has its own characteristics and should be selected according actual situationWith in-depth research,sEMG is widely used in rehabilitation medicine,especially in rehabilitation evaluation,prosthetics and rehabilitation robotics

Research development on the test methods of residual stress

Abstract: According to the research development on the ordinary test methods of residual stress,it was pointed out that the more suitable test methods were blind-hole and X-ray method.But the blind-hole drilling method may hurt specimen,X-ray method request strict test environment,and the other test methods can't fulfill industrial demand on effectiveness,accuracy and operation convenience.The residual stress measuring based on indentation has been considered noteworthy.The indentation response is related to residual stress existing in components.So the values from indentation response are in good agreement with that from the blind-hole method,meanwhile specimen hurt may be avoided,the residual stress measuring technology based on indentation response will definitely display its engineering application prospects.

Activity-Based Carbon-computing method for manufacturing process

Abstract: An activity-based carbon-computing method was proposed by using the thinking of activity-based costing for reference. Firstly, theconception and principle of the activity-based carbon-computing method were presented; then the carbon-computing model of the productmanufacturing process was established based on activity; the acquisition and calculation approach of the key elements of the computing modelwere analyzed and presented; Finally, a case study was presented, which demonstrates the validity of the proposed method. The research re-sult can be furtherly applied to the low carbon evaluation and optimization.

Application research of vision-location in robotic assembly equipment

Abstract: Aiming at the lack of auto-calculation of workpiece's positions in robotic assembling process,the mobile-phone lens(including LENS section and BARREL section)cartesian coordinates robotic assembly equipment based on vision-location was investigated.After the analysis of the workpiece's center coordinates with template matching,the assembly relationship between LENS and BARREL was established.A method was presented to acquire the image at every position,and the center coordinates of LENS and BARREL were calculated,the robot was driven to move to the right place with vision-location.The position and orientation continuity for robotic assembling were evaluated on the process of guiding robotic assembling,the assembling equipment's working at the same couple workpiece's positions were tested.The experimental results show that the analysis lays an important foundation for the further developing work of robotic assembly equipment.

Stability simulation and parameter optimization of load sensing pump

Abstract: Aiming at the problem that the large pressure bias and the poor stability of the load sensing pump,a virtual prototype of a load sensing pump was developed by combining Pro/E,ADAMS and AMESim.Through analyzing the pump's working principle and the simulation results,a method that how to match the volume and the diameter of damping orifices was reached.Based on this method,the 56 cc/r load sensing pump was optimized,and the better match effect of volume and damping orifice was gotten.The feasibility and effectiveness of this method were verified through many experiments.The results indicate that the load sensing pump optimized shows a stable performance,and the output pressure bias and vibration are decreased in high pressure condition.

Modeling and simulation at temporary power-off state of EMU traction driver system

Abstract: In order to research the performance of electric multiple unit(EMU) traction driver system at different states,according to the actual structure and parameter of CRH2 EMU,the simulation model of its traction driver system was established by Matlab/Simulink software.In this model,the transient current control and indirect rotor magnetic field orientation vector control strategy were adopted by traction motor,and the sine pulse width midulation(SPWM) and space vector pulse width modulation(SVPWM) modulate method were used by traction converter.On this basis,operation performance of traction converter was simulated and analyzed under different train speed when the pantograph temporarily disconnect to grid.The simulation results provide a reference for the actual design and performance analysis of traction converter.

Research of multi-stage charging method for on-board lithium battery of electric vehicles

Abstract: In order to achieve the fast charging and discharging of the on-board lithium battery of electric vehicles(EV),the multi-stage charging method of the EV lithium battery was investigated and the charging circuit topology was presentedThe method combined three charging methods(constant-current method,constant-voltage method and low-current method) was used to control a power converter by monitoring the battery voltage and current for intelligent fast chargingThe experimental results indicate that the battery voltage can reach the rated value in 30 minutes as being charged by the system,then the battery will soon be fully charged by using the constant-voltage methodThe research lays the foundation for the improvement of the charging efficiency and the charging security of the on-board batteries

Design of a wireless data acquisition system based on the simplify ZigBee protocol stack

Abstract: In accordance with traditional artificial data acquisition or advance wiring cable way limitations,a new wirless data acquisition system was designed.The hardware and software of system was analyzed and designed in detail.The wireless node used TI's cc2430 and temperature,light sensor module.The simplify ZigBee protocol stack was modified and planted,and the appliacations and related drivers were grammed.The results indicate that the workload of workers was reduced,and without wiring,to ensure the effectiveness of real-time data,the system can work in high temperature and high pressure and high risk specific environment environmental monitoring.

Simulation & analysis of pressure compensation valve in LUDV multi-way valve

Abstract: In allusion to the pressure compensation valve of LUDV multi-way valve,what a key role it played in the system and established its simulation model in AMESim was described.The model was proved to be accurate by simulation and experimental results.The results show that it would weaken the hydraulic shock by addding a small stiffness spring to the LS chamber of the pressure compensation valve,and by appropriately increasing the diameter of the orifice in the pressure compensation valve would not affect the valve's response speed either reduced hydraulic shock.

Load modeling of CRH3 electric multiple unit traction drive system

Abstract: Aiming at how to analyzing the load characteristic of traction power supply system and establishing a high-speed railway power supply quality evaluation platform,a Matlab/Simulink model of CRH3 electric multiple unit(EMU) traction and drive system was established by using vector control.According to the characteristics that main portion of this EMU load is induction motor,a model of induction motor paralleling static part was used to establish a mathematical model of this EMU.Particle swarm optimization(PSO)was used to estimate the parameters of this model,and good fitting results were obtained of power by using the parameters.The results indicate that this model can describe the dynamic characteristic of EMU load very well,also it proves that the identification algorithm is effective.

Harmonic analysis algorithm based on six-term cosine window interpolation FFT

Abstract: It is very difficult to achieve synchronous sampling and integrated-cycle truncation when power system harmonics are analyzed.Therefore,there inevitably exists spectral leakage and fence effect.The windowed interpolation FFT algorithm is the effective method to reduce spectral leakage and fence effect.In order to reduce long range leakage,a 6-term cosine window function was applied to harmonics analysis of power system.The interpolation estimation formulas of harmonics parameters were derived,moreover its interpolation coefficient has explicit expression and computation load is low.Comparison with the Hanning and Blackman-Harris interpolation FFT method was conducted by Matlab simulation.The result verifies the higher analysis accuracy of the proposed algorithm.The analysis results to testing data of microwave oven current further demonstrate the validity of the proposed algorithm.

Design of central air conditioning duct cleaning robot control system

Abstract: In order to solve the problems of central air conditioning duct diameter non-standard and the difficulty of the duct cleaning,the automatic centering technology was investigated.After analysing the central air conditioning duct cleaning robot control system,adopting a modular design thought,taking ATmega64 microcontroller as the control core,the relations between modules were established.A method was presented to the central air conditioning duct cleaning robot control system design.The cleaning technology was evaluated based on the existing cleaning technology.The results show that the cleaning robot can achieve automatic centering to adapt different pipe diameters to finish cleaning tasks,provide a broad application prospects for central air conditioning duct cleaning technology.

Improved algorithm of fault location on overhead power line and high voltage cable hybrid line

Abstract: In order to improve the accuracy of fault location on overhead power line and high voltage cable hybrid,and solve the problem of pseudo roots,an improved algorithm of fault location on hybrid line by two-terminal asynchronous information was proposed.Based on distributed parameter hybrid line model,the cause of pseudo roots in the fault location was analyzed,binary search to avoid pseudo roots was improved,the improved algorithm was used to locate fault,and the results and auto-reclosing technology were cooperated.Accordingly,the safety and reliability of the power system were improved.Matlab simulation results show that the fault location algorithm does not be affected of pseudo roots,transition resistance,fault type,fault position and asynchronous angle,and it shows that the fault location algorithm is fast and accurate.

Application of intelligent PID algorithm in finance temperature control system

Abstract: Aiming at the problems of the time-varying,nonlinearity and uncertainty of parameters and the status that traditional PID control is hard to meet the high stable constant-temperature requirement,a new system based on intelligent PID controller and PIC1684 microcomputer was investigated in industrial furnaces.This system used thermocouple to measure the temperature of furnace,and the transmitter carried the signal to A/D0809.Then the PIC1684 microcomputer achieved the deviation according to being given values,carried on an intelligent PID control and outputted the control quantity to adjust the angle of silicon.Thus the system would control temperature.The results show that this temperature control system has the characteristics of static accuracy,adaptability,reliability,and anti-interference.And good effects of temperature is achieved by this controller in electric heaters.

Automatic control system in regenerative aluminum melting furnace

Abstract: In order to realize the safety,energy saving,continuously run of regenerative aluminum melting furnace,the modern automatic control system was integratedBased on the analysis of the process characteristics of regenerative aluminum melting furnace,the relationship between the production process and the automatic control system was established,and the appropriate control system and control strategies were establishedthrough the application of the case,the relevant process control strategies are fully implemented and embodiedThe result shows that the automatic control system meets the regenerative melting furnace production process requirements

BP neural network based image segmentation technique for small sized league soccer robot team system

Abstract: BP neural network was adopted in the small sized league(SSL) robot soccer team for image segmentation in order to fulfill the requirements of real time processing and environmental light adaptation.The theoretical relationship between the image segmentation and BP neural network was studied,and the model of the BP neural network was established.The array of each component values(H,Cb,Cr) of all the pixels in the image were taken as the input of neural network,and the arrays of target pixel categories as the output.The convergence rate was improved by optimizing the learning ratio parameters and the error function definition.The background-subtraction method and normalization algorithms were applied to speed the segmentation process.The image segmentation experiment shows that the model and algorithm of BP neural network can solve the image segmentation problems for small size soccer robot vision subsystem,and demonstrate good performance in real timing and adaptability in different lighting conditions.

Definition evaluation function of digital image in auto-focusing system

Abstract: In order to slove the problems of auto-focusing technology based on image processing,it is the key step to use the accurate and effective functions.The role of Gradient function,Spectrum function and Entropy function in auto-focusing system was analyzed and compared by experiment in auto-focusing system.The performances and features of these functions in experimenteral platform were studied.Experiments results indicate that Tenengrad function,Brenner function and Square Gradient function has high sensitivity features in focal plane,when defocus serious,the tread of change is not clear,this can be applied in accurate focus equipment.Variance function has good Single-Peak and sensitivity,characterize the preferable efficiency,has high single-to-noise,better reliability,than other ones.It can better meet the requirement of the image definition evaluation,can be applied in digital image auto-focusing system.

Vision based automatic assembly of rotor leads for micro-motors

Abstract: In the manufacture of micro-motor,it is an important working procedure to weld the head of coil onto the bonding pad.Due to the particularity of the objects,all the welding working,in present,are completed by human labor under microscope,leading to high cost,low efficiency and poor consistence.Aiming at these problems,a technique about vision based automatic welding was presented,that is,adjusting the position and posture of motor using vision automatically.In addition,the head of coil was positioned by the use of airflow and the error made by the interference between adjustment of position and posture was analyzed and the solution was given finally.The results indicate that the head of coil can be positioned well by airflow and the precision of adjustment of position and posture using vision control reach 10 μm and 1° respectively.

Human-machine system reliability based on fault tree method

Abstract: In order to solve the problem of improving the reliability of man-machine system design,the fault tree analysis method was applied to the human reliability analysis of system design,the reliability of man-machine system design by fault tree was analyzed from the human point.Firstly the minimal path sets of the fault tree were identified.The basic events which are impact on the reliability of man-machine system were analyzed,from the importance of structure,the probability importance,critical importance.The main factors that affect the man-machine system reliability were identified,more information was provided to product design for the production of man-machine system.The results show that human errors caused by the design are the key factors affecting system reliability,among the factors that affect the reliability of man-machine system design.

Direct digital frequency synthesis function generator

Abstract: Aiming at high integration and low cost requirements at function generator module of integrated test instrument,a digital function generator was designed based on the direct digital frequency synthesis(DDS) technology.It consisted of three parts-microprocessor systems DDS system,analog channel.Phase accumulator and the ROM stores waveform table in field programmable gate array(FPGA) were designed,to change the wave frequency by load frequency control word,to achieve the digital part of DDS system,and the MCU of W77E58 was microprocessor systems of the function generator.The test results indicate that the design of the function generator can produce sine wave,square wave and triangular wave,and accords with the system requirements on the waveform amplitude,frequency,precision of the indicator.

Application of Agilent 34972A in temperature sensor detection system

Abstract: In order to slove the problems of massively producing temperature sensors for heat meters and matching them,after the analysis of their characteristics,the temperature sensor detection system using Agilent 34972A data acqusition system was established.It was programmed using VC language with VISA library to drive the instrument to measure and read the data.And,a program applied was given in data processing and mating the temperature sensors.The experimental results show that,using Agilent 34972A to measure the temperature sensors of heat meter,not only improves the measurement accuracy,but also shortens the detection time.

Research on fuzzy diagnosis method for air brake of diesel locomotive

Abstract: In order to solve the problems of diagnosis method for air brake of diesel locomotive hysteresis-free,a diagnosis method to combine the wavelet analysis with the expression of fuzzy production rule was investigated.After the analysis of relationship between the brake of diesel locomotive's varying rate of internal pipeline pressure and its fault cause,a method was presented to combine the wavelets multiscale edge detection for extracting the symptom of the failures with the expression of multiple symptom fuzzy diagnosis knowledge.The diagnosis methods for air brake of diesel locomotive were tested.The experimental results show that the diagnosis system can improve the real-time and veracity of the diagnosis for air brake of diesel locomotive effectively.

Hydraulic robot joint research based on hydraulic rotary servo

Abstract: Aiming at the problem that the development of hydraulic robot joint is restricted by joint dimension,movement range and control precision,a hydraulic rotary servo valve was proposed,in which the valve spool stress is balance in radial direction and servo dead zone is small.A hydraulic robot joint was designed based on the hydraulic rotary servo valve.The hydraulic robot joint dimension is compact,and its output torque is larger.The simulation experimental results show that hydraulic robot joint has high response rate,good motion stationarity,high movement precision,and larger load capacity.

Design of wireless power transfer system based on resonant coupling

Abstract: Distance and efficiency is the development bottleneck of wireless energy transfer system.Resonant coupling technology can solve this problem effectively.From the circuit mode of receiving and emission coil,it was found that detune is the key reason of low efficiency based on the deep studying of resonant coupling system.And then,a wireless pave fransfer system was desinged,which the rated transmission power is 30 W and the transmission frequency is 1 MHz.Also,frequency-tracking technology was used in the emission coil to reduce power loss when detuning.Lastly,experiment validates this design and it has a good coherence with the theory calculations.

Integration method and model based on node autonomy for heterogeneous video surveillance systems

Abstract: With an ever-increasing usage of video surveillance systems,the demands for resource sharing become a topical subject.However,it is always troublesome to extend and stabilize such systems.Aiming at above shortcomings,a model based on the node autonomy was proposed.Defining and using service nodes,not only the heterogeneity of the systems was solved,and the independence of each system was enhanced as well.Also,in terms of self-describing service of video nodes,the extensibility of the model was obviously increased.Confirmed by numerical applications as reported,the results indicate the feasibility and advantages of the proposed method.

Analysis of transient characteristics for shipborne piezoelectric ceramic of ultrasonic liquid level transducer

Abstract: It is difficult for the traditional analytical method to analyze the transient characteristics of piezoelectric ceramic.In order to solve the problem,the finite element method(FEM) was investigated.After introducing FEM theory,the solution to the key operation process were suggested,and the model of piezoelectric ceramic used for a certain type of marine ultrasonic liquid level transducer was built using the ANSYS software.On the condition of acoustic emission and the receiving,the effect on electro-mechanical transformation efficiency and the stress field profile of two forms of compressive stress was simulated separately.The results indicate that the electro-mechanical transformation efficiency can be raised by virtue of compressive stress of ring-shaped distribution,and the sensitivity of the transducer can be raised consequently.However,it causes the appearance of stress concentration and cycle.

Method for reducing cogging force by optimization of the pole arc in permanent magnet linear motors

Abstract: Force ripple caused by cogging force is one of the main reasons which prevent permanent magnet motors from acquiring high performance.Aiming at reducing cogging force in permanent magnet linear motors,taking into account of the structural features of linear motors,an analytical method based on energy method and Fourier series was proposed to obtain the expression of cogging force which was related with pole-arc.End force,which was closely related with the length change of the secondary rod,can also cause force ripple,a method based on different combinations of pole-arc for reducing cogging torque was proposed to avoid excessive length change of the secondary rod.Simulation and experiment results show that the method can be effective to reduce cogging force and improve the motion performance of the permanent magnet synchronous linear motors.