US 2005/0038532 A1 · Apparatus and method of controlling single-input-multi-output systems

Abstract

An apparatus and method is disclosed for automatically controlling single-input-multi-output (SIMO) systems or processes. The control output signals of a plurality of single-input-single-output (SISO) automatic controllers are combined by a combined output setter so that these SISO controllers are converted to a multi-input-single-output (MISO) automatic controller based on certain criteria; and its resulting controller output signal is able to manipulate only one actuator to control a plurality of continuous process variables or attempt to minimize a plurality of error signals between the setpoints and their corresponding process variables. Without the need of building process mathematical models, this inventive apparatus and method is useful for automatically controlling unevenly paired multivariable systems or processes where there are less system inputs than outputs including but not limited to industrial furnaces, rapid thermal processing (RTP) chambers, chemical mechanical planarization (CMP) systems, and distillation columns.

Claims34

Dependent claims

A multi-input-single-output controller for a process having a plurality of process outputs which are controlled by one controller output applied to one actuator whose output is the input of said process, said controller comprising:

a) a plurality of neural networks each including:
i) an error input representative of the difference between a predetermined setpoint and one of said process outputs;
ii) a normalization unit for normalizing said error input to a predetermined range of values;
iii) a scaling function for scaling said normalized error input to produce a value E1 of the form
E
1
=
K
c
T
c
⁢
N
⁡
(
e
⁡
(
t
)
)
,
or an equivalent thereof, in which Kc is the controller gain;
Tc is the user-selected time constant of said process;
N(.) is the normalization function of said normalization unit;
and e(t) is the value of said error input at any given time;
iv) a layer of input neurons having as their inputs successively time-delayed values of E1;
v) a layer of hidden neurons each having as its output the sum of individually weighted ones of said successively time-delayed values of E1;
vi) an output neuron having as its output the sum of a first function of the individually weighted outputs of said hidden neurons;
vii) a control signal which is at least in part the denormalized value of a second function of the output of said output neuron;
and
b) said control signals of said plurality of neural networks being combined by a combined output setter to produce said controller output.

29 more elements

Dependencies are inferred from the claim text.

Apparatus and method of controlling single-input-multi-output systems

Life of this patent

Apparatus and method of controlling single-input-multi-output systems

Life of this patent

Abstract

Claims34