| Summary: | 博士 === 大同工學院 === 機械工程學系 === 84 === A predicted fuzzy controller (PFC) incorporating a fixed metal
removal rate(MRR) controller is designed in this disseration for
the sake of the extention of the tool life and improving the
cutting productivity. The fuzzy control techniques and the grey
theory are integrated to develop a PFC to the constant turning
force operation. The most important difference between the PFC
and the conventional fuzzy control(FC) is that the fuzzy control
signal is determined by the future predicted state value
obtained by a grey model instead of the present state value used
in the traditional fuzzy controller(FC). Hence, one can get the
control signal in advance and avoid the system out of safety. On
the other hand, an auxiliary fixed metal removal rate(MRR)
controller, which can be determined by the lathe power or
machining roughness or tool chatter...etc, on the constant
turning force (CTF) operation is adopted. When the controlled
plant is a nonlinear function, the productivity will always
decrease due to the feed decreases much rapidly with the
increases of cutting depth, thus MRR reduces accordingly. A
reasonable solution is to increase the cutting speed.
Consequently, the concept of the MRR is built in the auxiliary
controller to improve the CTF control system. Because of the
prediction ability of grey model, the two inputs of the fuzzy
controller, error signal and error change signal, keep more
stable than that without prediction model. The PFC system with
MRR controller is more robust than that of the traditional FC
system.
|
|---|
