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Volume 4
Nano Research & Applications
ISSN: 2471-9838
Page 99
&
JOINT EVENT
October 04-05, 2018 Moscow, Russia
2
nd
Edition of International Conference on
26
th
International Conference on
Advanced Nanotechnology
Materials Technology and Manufacturing Innovations
Advanced Nanotechnology 2018
& Materials-Manufacturing 2018
October 04-05, 2018
Nano Res Appl 2018, Volume 4
DOI: 10.21767/2471-9838-C5-021
Extended adaptive control for electrical discharge machining
Ming Zhou
Beijing University of Civil Engineering and Architecture, China
E
lectrical discharge machining (EDM) has been used widely in industries over 8 decades because of its two remarkable
advantages over conventional machining technologies: non-contact machining and machining conductive materials
of any hardness. However, its essentially weak stability of machining restricts sustained machining in poor flushing
conditions, especially in machining materials of high melting points like molybdenum-titanium-zirconium (TZM) alloy
and the materials of low thermal conductivities like titanium and Inconel 718, etc. To solve this issue, some efforts of
analyzing and disclosing EDM process dynamical properties had been paid. EDM process is, in fact, a non-stationary
and nonlinear process with strong stochastic disturbances and the adaptive control theories seemed most likely fit for it.
However, the first developed adaptive control system with minimum-variance control law, though the machining rate
has been doubled, still had troubles in stabilizing EDM processes, especially in non-stationary stages. A new approach
with minimum-variance and pole-placement coupled control law was studied and testified more feasible in dealing
with machining in non-stationary stages. However, significant improvements had been achieved when two-step-ahead
prediction control law was studied. Further explorations of EDM processes revealed that both of machining situation
and machining state were changing all the time while in machining. If machining situation and machining state were
considered simultaneously, more robust control systems for EDM would become possible. Thus, a new control system
which was called an extended adaptive control systemhas been developed. In this system, there were two control variables
working harmoniously in parallel to control the machining situation and the machining state respectively. This control
system not only sustained fast and stable EDM, but also extended its efficient machining in machining molybdenum-
titanium-zirconium (TZM) alloy, titanium alloy, and Inconel alloy, as well. More importantly, this new approach solved
an issue once considered bottleneck constraint in 1991 that there existed coupling disturbances from one control variable
to another in machining which has restricted the development of multivariable control systems for EDM.
zhouming@bucea.edu.cn