Applied Mechanics and Materials Vol. 697

Abstract: For mill gearbox fault detection problems, and puts forward combining support vector machine (SVM) and genetic algorithm, is applied to rolling mill gear box fault intelligent diagnosis methods. The choice of parameters of support vector machine (SVM) is a very important for the SVM performance evaluation factors. For the selection of structural parameters of support vector machine (SVM) with no theoretical support, select and difficult cases, in order to reduce the SVM in this respect, puts forward the genetic algorithm to optimize parameters, and the algorithm of the model is applied to rolling mill gear box in intelligent diagnosis, using the global searching property of genetic algorithm and support vector machine (SVM) of the optimal parameter values. Results showed that the suitable avoided into local solution optimization, the method to improve the diagnostic accuracy and is a very effective method of parameter optimization, and intelligent diagnosis for rolling mill gear box provides an effective method.

Abstract: In order to forecast the malfunctional state of main power plant on ships through predicting the trend of unsteadily changed thermal performance parameters in main power plant system, this paper established AR model for thermal performance parameters using time series analysis method, by which to predict the change trend analysis of thermal performance parameters, and comparing the predicted values and the measured values. The actual application case of predicting a main engine’s exhaust temperature has been validated by using of the AR model, and results showed that: AR model can accurately predict the change trend of smoke temperature, and the prediction precision is higher, the average relative error was 0.25%.

Abstract: The design and debugging of motor control algorithm for electric drive tracked vehicle as the research object, this paper proposed a graphical model programming method of the code directly generated based on vector control algorithm model of the permanent magnet synchronous motor created in Matlab/Simulink. After simulation analysis and verification, this paper using real time toolbox automatically generated the embedded C code and implemented a processor in the loop test. The test results show that the longest running time of the control algorithm was 7.1633μs, between code and algorithm model, had high functional equivalence .This programming method is simple and intuitive, easy debugging, stable operation, and provides an effective way for motor drive system software development of electric drive tracked vehicle.

Abstract: The scuffing of friction pair is a common phenomenon in conditions of high speed and pressure. It was researched on scuffing characteristics in this paper. By using UMT-3 friction and wear tester, the friction and wear characteristics of slipper pair material in hydraulic component were investigated, and the friction coeficient-speed curves in the different pressures were got, as well as the wear rate-speed curves. The worn surface morphology of pin specimen was photographed by SEM, and the formation mechanism of the worn surface was analyzed. The results suggested that: friction coefficient and wear rate would have a jump when the scuffing occurred, the friction and wear characteristics would be affected by the interaction of pressure (P) and speed (V) . The PV characteristic restricted the correlation between working pressure and speed.

Abstract: Removed at Authors Request.

Abstract: In order to manage the power of electric drive system effectively and improve the fuel economy and working efficiency of electric drive tracked vehicle, this paper proposed a novel energy management control strategy based on the theory of threshold logic and fuzzy logic. The mathematical models of the key components of electric drive system were built in SIMULINK. To examine and analysis the efficiency of control strategy, a driver-controller based HILS (hardware-in-the-loop simulation) platform was built and the energy management control strategy was verified. The simulation results reveal that the strategy have excellent performance in energy distribution, fuel saving and working efficiency, and the proposed control strategy is simple and easy to realize in a real controller, which provides an effective method for the design and application of energy management control strategy of electric drive tracked vehicle.

Abstract: Motion precision is an important evaluating index to evaluate the quality of the mechanisms. On the premise of fully studying the motion of joystick in the excavator, a new kind of joystick-control mechanism is proposed. The dynamics simulation model of the mechanism is constructed by ADAMS, so the dimension error and initial angle error of joint in the installation is analysed. Random sampling method are adopted to simulate the error of position of two key points, the simulation of transverse and longitudinal swing of is completed, and the effect on the motion precision of joystick is compared which is made by error of each direction of two key adjusting points. The motion reliability of the joystick-control mechanism is calculated, combined with the stress-strength interference theory.

Abstract: In this paper, according to the requirements of the self-propelled-gun’s hydraulic system test technology, using variable speed metering pump technology, a variable cain pressure predictive controller is developed. This method can improve response speed of pump-valve combined control. Then the self-propelled-gun’s external hydraulic source is developed, which can test a variety of self-propelled-gun equipment operation and its hydraulic system without starting the host. The trial operation proves: this test equipment is high common, high stability and high integration.

Abstract: Electrical discharge grinding is used to machine polycrystalline diamond layer of cutting tools, which can effectively drill composite/titanium stacks in modern aircraft frames. In the machine, an electrode wheel is rotated to accelerate debris flushing to quickly recover the dielectric fluid between a spark gap. The aim of this study was to investigate the effect of the wheel speed on polycrystalline diamond removal rate for high erosion efficiency. Multiple wheel speeds were applied in a electrical discharge grinding machine under various pulse on-times and the volumetric removal rates were calculated by the precise position feedback of this machine over the time, which was obtained by the electrical waveform of discharges. The experimental results show that the removal rate increases with the wheel speed up to a limit at the low range and then declines at the high range. This indicates that the wheel speed needs to be optimized for high erosion efficiency under various discharge conditions such as different materials and pulse on-times.

Abstract: Automated Mechanical Transmission achieves automatic shifting by applying electronic control technology in traditional dry clutch and Manual Transmission,not only having the advantages of automatic transmission, but also keeping the performance of the original manual transmission. This paper generally introduces the function and performance characteristics of Automated Mechanical Transmission, and elaborates its system structure, working principle and key technology. The key technology is divided into 4 parts, including Electronic Control System, Clutch Control, Shift Strategy and Design and Optimization of the Actuator. Combining with the related companies' research and development products, the performance of the Automated Mechanical Transmission is further analyzed. At the same time, according to the current research status in the world, putting forward the following research focus and development trend of Automated Mechanical Transmission.Keywords: Automated Mechanical Transmission; Key Technology; Development Trend