Key Engineering Materials Vol. 620

Abstract: Connecting rod is often in high speed movement as one of the main parts of automobile engine. It’s shape error and accuracy of the hole or the plane will directly influence the working performance and the service life of engine. So the production has very strict requirements on the shape error. Connecting rod standard gauge block, as a standard part of manufacturing connecting rod, it’s manufacturing accuracy is higher, and the measurement and calibration of error directly affects the machining efficiency and the precision of the connecting rod. CMM develops so fast that constantly pounding all kinds of special measuring equipment. In the contact, a digital measurement is carried out for the key dimension and the space shape error of connecting rod standard gauge block. so data processing of the measuring results has been obtained, then reconstructed geometry elements of the plane and round hole ,etc., and got the required shape error by the contact CMM, it provides the basis for improving machining precision of the connecting rod.

Abstract: A prediction method based on least square support vector machine is introduced into the surface roughness prediction model in low-frequency vibration cutting. The model is created with low-frequency vibration cutting experiment for the corresponding relationship between vibration parameters and cutting parameters and the workpiece surface roughness. The training sample set is constructed to train regression models of least square support vector machine through experimental data. Identification of training sample set is done to gain the regression parameters a and b. The amplitude of A, vibration frequency f, feed f₁ and spindle speed n are used as the input variable in X_i. Predicted values of surface roughness are forecasted with the model. Evaluation is made with the difference between the predicted value and experiment. Comparison with BP neural network and support vector machine method has shown that the least square support vector machine prediction model works faster than SVM method, the prediction error is about 29% of that by support vector machine, and the prediction accuracy is higher than the BP model.

Abstract: Owing to nonlinearity, time-delay and complexity of pressure control system in vacuum casting (VC) process, the traditional pressure tuning method can’t guarantee the good performance and thus high quality product nowadays. In this paper, a novel pressure control strategy for vacuum casting process, combining fuzzy PID and neural network methods, is proposed to solve this problem. The proposed strategy can on-line regulate pressure difference between low and upper chambers of VCM to meet the pressure requirement in VC process, thus ensuring high quality part. With the aid of Matlab and configuration software – Forcecontrol, the proposed fuzzy self-tuning controller is implemented in a sample machine. The experiment result shows that the presented pressure controller can track the pressure profile accurately and thus can further improve the product quality.

Abstract: The cooperator’s optimal selection is a difficulty in manufacturing supply chains, but the complex networks developed rapid recent year provide us a new method. It proposed a probability distribution model for optimal selecting cooperator in supply chains. Analyzed the growth of Manufacturing Supply Chain Network Relationship Graph (MSCNRG) firstly, and put forward a probability distribution function consisted with degrees, relationships and conditions of the vertices; some experiments were carried out to check the model. The results of probability distribution model provide a novel method to analyze the optimal selecting cooperators in supply chains.

Abstract: Audio fingerprint technology has been increasingly played an important role in audio content identification, audio information security, industrial process monitoring, etc. Due to compressed format has become the main way for audio files storage and transmission, it owns more practical significance that directly extracting audio fingerprint from compressed-domain. In general, existing compressed-domain audio fingerprint schemes are robust to common time-frequency-domain distortion, including noise, echo, band-pass filtering, 32Kbps@MP3 and others. But they are difficult to deal with large linear speed change distortion which is a frequent audio processing means in the field of television and broadcast. This paper proposes a novel compressed-domain audio recognition algorithm, which can resist linear speed change in the range of-10% to 10% (recognition rate is higher than 90%), via extracting fingerprint after do Fourier-Mellin transform for sub-band energy sequence of MDCT spectrum. This is enough to cope with almost all situations of audio acceleration/deceleration occurred in commercial application. In addition, it shows similarity in other performance compared with existing excellent compressed-domain audio recognition algorithms.

Abstract: As distribution network is of radial pattern, the forward and backward substitution algorithm and its variations are widely used for radial distribution network power flow calculation, which needs to form associated admittance matrix and matrix operations. This paper proposes a sequential numbering power flow calculation algorithm for distribution network. Based on the graph theory of nodes, the proposed method can handles multiple branches radiation network.. In the simulation test, our proposed algorithm is applied to a typical radial distribution network in order to verify the efficacy on power flow calculation. The results show that the sequential numbering power flow algorithm has good performance in terms of convergence rate and reliability.

Abstract: In wireless sensor networks where the volume and energy of nodes are limited by batteries, which are difficult or prohibitively expensive to replace or recharge in the most of its application scenarios, so improving energy efficiency has very important significance.Cooperative beamforming forms virtual antenna arrays by multiple adjacent wireless sensor nodes, which improves the signal strength at the receiver and reduces the energy consumption of the transmitter by multiplexing gain and interference management.In this paper, the problem of energy consumption optimization for cooperative beamforming in wireless sensor networks was studied. First, considering both amplifier energy consumption and circuit energy consumption,energy consumption models for both broadcast phase and cooperative beamforming phase was presented.Then,we propose a two-step optimization to minimize the total energy consumption by optimizing the modulation parameter and the number of cooperative nodes.We simulate the total energy consumption for various transmission distances,modulation parameters , path losses and the number of cooperative nodes.The numerical results show that,for different system parameters, selecting the optimal modulation parameter and the optimal number of cooperative nodes can reduce total energy consumption and improve energy efficiency.

Abstract: The artillery test of firing simulation provides the similar dynamic recoil effects of artillery, by means except firing. It is more safe and convenient with less ammunition and time consumed. This document describes the meaning and content of the artillery test of firing simulation. It analyses the feasibility of this test technology by calculating and comparing the experimental data of guns and makes a research and analysis for current situation and development of the related technology In the domestic and overseas. Through fuzzy comprehensive evaluation (FCE) and analysis hierarchy process (AHP), a comprehensive assessment on different simulation techniques is done. A research direction on the artillery test of firing simulation is proposed, which can meet the requirements of the development of modern artillery.

Abstract: Aiming to the young people’s requirements on mobile phone design, market research for target population is done. Requirements on mobile phone design are found. Compared to existing mobile phone, the direction of mobile phone conceptual design is planned. A novel conceptual mobile phone is designed based on TRIZ theory. Based on TRIZ theory, the solution process is simple, has clear goal, and the effect is outstanding. So TRIZ theory is a good way of innovation.

Abstract: Manufacturing is in transition to manufacturing service industry and Life Cycle Cost (LCC) becomes an important considerate index. Operation & Maintenance Expense (OME) is the most complicated one among all the LCC expense units. Besides, it also accounts for the largest proportion. Authors proposed a LCC modeling idea, which is Expenses attached to the process, while process consumes resourses. Authors take the air-supply and brake system of high-speed train as example, conduct the system’s maintenance FMEA and risk assessment based on dependability. According to assessment results, authors match the system’s important maintenance projects, including brake control system, main air compresser etc., with their respective maintenance mode. The paper put forward the expense model of one specific maintenance work on basis of its resourse structure. Based on the main air compresser’s dependability, authors predicted its Corrective Maintenance (CM) repair times by using Monte Carlo simulation. Combined with the repair times of Preventive Maintenance (PM) and condition-based maintenance, authors obtained high-speed train’s OME model. This method has important significance for modeling the high-speed train’s LCC. Besides, it may support the expense reseach for large equipments with complicated process.