智能自适应电火花加工

Intelligent Adaptive Electrical Discharge Machining (EDM)

摘要: 为最大限度发挥自适应电火花加工能力，更加科学地解决加工稳定性与加工效率的矛盾，提出了智能自适应电火花加工。即在“感知”间隙中放电脉冲的基础上，对信号做进一步的“认知”处理，获得极间环境状态指标和加工状态指标，然后根据实时变化的加工环境，计算出“控制行为的指导思想”，即获得平衡加工稳定性和加工速率的放电状态期望值，最后，根据这个期望值，获得当前加工状态的最优控制。智能制造的核心是“控制行为的指导思想”，是最优控制行为的指导原则；由自适应控制具体实现最优控制行为。本文通过两个自适应控制系统，实现了智能自适应电火花加工，即一个自适应控制系统完成“控制行为的指导思想”，另一个自适应控制系统完成最优控制行为。实验结果表明，该智能自适应电火花加工成倍地提高了电火花加工的能力，特别是针对核工业、航空工业等的高温合金、超硬合金如钼钛锆合金、镍基718合金等，都能够实现稳定、快速地加工，展示了智能自适应电火花加工的强大加工能力。

Abstract: To fully exert the ability of adaptive EDM and solve the contradiction between machining stability and machining efficiency, intelligent adaptive EDM has been studied and developed. Based on the “perceived” signals of discharge pulses in a gap between electrode and work-piece, the signals were computed to obtain machining situation state index and machining state index which were the outcomes of so called “cognitive process”. Then a machining state expectation index defined to be a "guiding criterion of control behavior" which was used to balance machining efficiency and machining stability had to be derived in terms of varied machining situations. With this criterion, an optimized control behavior had to be achieved. The core of the intelligent adaptive manufac-turing is the "guiding criterion of control behavior". The optimized control behavior was accom-plished by an adaptive control system. In this paper, two cascaded adaptive control systems were used to realize the intelligent adaptive EDM; one performed the function of the "guiding criterion of control behavior" and the other the function of the optimal control behavior. The experimental results demonstrated that the intelligent adaptive EDM has greatly improved the ability of EDM, especially in machining high-temperature alloys and super-hard alloys mostly in nuclear industries and aviation industries, e.g. molybdenum-titanium-zirconium alloy and inconel 718 alloy, etc., and proved that this control system can achieve stable and fast machining.