共查询到20条相似文献,搜索用时 717 毫秒
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电火花加工中放电间隙状态的识别技术研究 总被引:3,自引:0,他引:3
首先分析了电火花加工中放电间隙脉冲的四种典型状态,然后论述了间隙脉冲传统的识别技术和基于人工智能理论的识别技术,指出了基于人工智能理论用计算机软件进行的识别技术是这一领域新的发展方向。 相似文献
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模糊控制理论在电火花线切割机中的应用 总被引:3,自引:0,他引:3
通过对电火花线切割间隙状态的分析,提出了利用放电间隙状态的平均电压及其变化状况来判别加工状态优劣的方法,并在此基础上研制成功间隙状态模糊控制器,取得了令人满意的结果。 相似文献
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一种高速走丝切割加工间隙状态的检测方法 总被引:1,自引:0,他引:1
加工间隙放电状态的检测是电火花加工控制系统的一个关键环节,本文针对高速走丝电火花线切割加工,对放电间隙电压量的变化特性进行了理论分析和试验研究,提出了一种“变阈值电压法”的检测方法,经试验证明该方法可较好地对高速走丝电火花切割加工中间隙状态进行检测。 相似文献
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如何控制好放电间隙状态是提高电火花机床性能的关键之一。而识别放电间隙状态与建立描述其特性的数学模型是设计控制系统和改进性能的前提。一、放电间隙状态的分析放电过程中,因受各种因素变化的影响,如间隙的大小,脉冲参数,工件的几何形状,加工深度,工作液的压力、流场分布,废屑在间隙内分布情况以及其它大量随机因素,使间隙状态在迅速地变化着。 相似文献
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论文将多柔体动力学的建模方法引入柔性机器人的动力学分析中。应用Lagrange方程建立空间刚-柔耦合多体系统动力学方程,采用牛顿二状态模型,对含间隙机器人的副间接触和分离过程,建立了铰接间隙动力学方程。仿真分析结果表明,由于间隙铰的存在。间隙运动副反力呈现大幅度连续波动现象,使整个机器人的稳定性大大降低。而当记入大臂的柔性后,间隙副反力的波动减小,所以,机器人可以通过适当添加弹性补偿单元降低部分副间碰撞时的冲击效应,提高机构运转的稳定性。 相似文献
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往复走丝线切割加工过程中电极丝的横向振动是影响加工质量的重要因素,制约了其进一步应用发展。基于此,对电极丝振动的产生原因和影响因素进行深入分析,设计了一种智能张力控制系统,通过检测间隙放电过程中的间隙电压和间隙电流,应用模糊算法识别采样周期内的间隙放电状态,然后对间隙放电状态中火花率的占比情况二次应用模糊算法得出紧丝机构所需要的进给量。经实验验证,这种方法可以通过张力控制来减少电极丝的振动,使工件的表面粗糙度和尺寸误差分别减低13.4%和9.5%,有效地提高了往复走丝线切割的加工质量。 相似文献
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C.C. Kao Albert J. Shih 《International Journal of Machine Tools and Manufacture》2006,46(15):1996-2008
Monitoring the gap voltage and current in micro-hole electrical discharge machining (EDM) using high-speed data acquisition with 0.5 ns sampling period is conducted. The spark and arc pulses at three stages, namely electrode dressing, drilling, and penetration, of the micro-hole EDM are recorded. The EDM process parameters are setup to use negative polarity to blunt the electrode tip and positive polarity for micro-hole drilling and penetration. A new phenomenon of pre-discharging current is discovered. In the first 20–30 ns of spark and arc pulses, the current starts to rise while the voltage remains the same. Effects of EDM process parameters, including the open voltage, electrode diameter, and polarity, on the rate of spark and arc pulses and electrode feed rate are investigated. A model based on the RLC circuit is developed to study the ringing effect at the end of a discharge. The intrinsic parasitic capacitance and resistance of a RLC circuit are calculated from the decaying voltage signal and compared under two sets of experiments with varying wire electrode diameter and gap voltage to validate the ringing model. The calculation and experimental results validate the proposed RLC model for ringing phenomenon. The model shows the electrode diameter has negligible effect on ringing and high open voltage increases the parasitic resistance and damping in ringing. The monitoring technique and ringing model developed in this research can assist in the selection and optimization of micro-hole EDM process parameters. 相似文献
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In order to improve the performance of machines, there is a growing need to develop a highly stable servo control system for electrical discharge machining (EDM). With the perpetual push towards the untended EDM operation, an adaptive control system is and will continue to be a primary option. In this paper, a new EDM adaptive control system which directly and automatically regulates tool-down-time has been developed. Based on the real-time-estimated parameters of the EDM process model, by using minimum-variance control strategy, the process controller, a self-tuning regulator, was designed to control the machining process so that the gap states follow the specified gap state. With a properly selected specified gap states, this adaptive system improves the machining rate by, approximately, 100% and in the meantime achieves a more robust and stable machining than the normal machining without adaptive control. This adaptive control system helps to gain the expected goal of an optimal machining performance. 相似文献
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An analogue wattmeter has been developed for direct measurement of electrical power dissipation at the discharge gap during electrical discharge machining (EDM). A microcomputer samples power and corresponding gap voltage at regular intervals. Digitally encoded waveforms, which represent blocks of continuous power and voltage pulse trains, are stored on floppy disks for subsequent display and analysis. The advantage of using this microcomputer-based integrated measurement system is the ability to capture both typical and random events or phenomena in EDM and also to extract and process information from the digitized waveforms which represent characteristics of these events.In this investigation, samples of power and voltage pulse characteristics during four EDM tests have been recorded, analysed for unit and time-averaged variations and meticulously studied with the aid of the microcomputer-based system. Power and voltage waveforms have been reconstructed from the digital data and are suitably displayed. Random and systematic or cyclic variations as shown by the analysed data, together with the corresponding reconstructed waveforms, are presented. Reasons for the variations are discussed in the light of similar observations verified by other researchers.This paper reports part of a continuing programme involving the use of microcomputer-based measurement systems for both on-line monitoring and off-line analysis of the EDM process. 相似文献
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Masahiro FujikiGap-Yong Kim Jun NiAlbert J. Shih 《International Journal of Machine Tools and Manufacture》2011,51(1):77-83
A new gap control strategy for five-axis milling using near-dry electrical discharge machining (EDM) has been experimentally investigated. The conventional EDM control strategy only allows the retraction of the electrode in the direction of machining trajectory, which results in inefficient gap control when the electrode is not perpendicular to the workpiece. The new gap controller is capable of retracting the electrode in the direction of its orientation. This enables more efficient enlargement of the discharge gap leading to faster recovery of average gap voltage. Experimental results show a 30% increase in material removal rate while the tool electrode wear ratio and surface roughness are not affected. Furthermore, EDM efficiency is improved due to the change in the electrode retraction in its axial direction. The gain tuning of the proposed controller is also discussed. This study shows the direction of electrode retraction is important for five-axis near-dry EDM milling. 相似文献
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Y.S. Tarng C.M. Tseng L.K. Chung 《International Journal of Machine Tools and Manufacture》1997,37(4):511-522
In this paper, the use of fuzzy set theory to construct a new pulse discriminator in electrical discharge machining (EDM) is reported. The classification of various discharge pulses in EDM is based on the features of the measured gap voltage and gap current. To obtain optimal classification performance, a machine learning method based on a simulated annealing algorithm is adopted to automatically synthesize the membership functions of the fuzzy pulse discriminator. Experimental results have shown that EDM discharge pulses can be not only correctly but also quickly classified under varying cutting conditions using this approach. 相似文献
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This paper describes improvement of the machining characteristics of dry electrical discharge machining (dry EDM) by controlling the discharge gap distance using a piezoelectric actuator. Dry EDM is a new process characterized by small tool electrode wear, negligible damage generated on the machined surface, and significantly high material removal rate especially when oxygen gas is used. However, the narrow discharge gap length compared with conventional EDM using oil as the dielectric working fluid results in frequent occurrence of short circuiting which lowers material removal rate. A piezoelectric actuator with high frequency response was thus introduced to help control gap length of the EDM machine. To elucidate the effects of the piezoelectric actuator, an EDM performance simulator was newly developed to evaluate the machining stability and material removal rate of dry EDM. 相似文献
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This paper describes the development of a pulse generator for nano EDM using a capacity coupling method. To obtain discharge craters of nanometer diameter, a pulse generator was coupled to the tool electrode by a capacitor. Since the influence of the stray capacitance in the electric feeders can be eliminated, the discharge energy can be minimized to accomplish nano EDM. This method also allows non-contact feeding of electric current to the rotating spindle, minimizing the run-out of the tool electrode. To control the gap width, the gap voltage was also measured using the capacity coupling method. 相似文献
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