Adaptive control methods and apparatus using frequency analysis of time series data

An adaptive control method for controlling a process by calculating a manipulated variable from a deviation between a setpoint variable and a control output variable and then using said manipulated variable, said method comprising the steps of:

• performing frequency analysis on time series data of said control output variable;
• determining a range of periods within which rate of change in frequency response amplitude of said control output variable in relation to gain ratio is positive;
• and
• increasing control gain by a given value when maximum value of an amplitude obtained by decomposing said time series data within said range of periods into frequency components is larger than a first value, or decreasing said control gain by a given value when said maximum value is smaller than a second value.

An adaptive control method for controlling a process by calculating a manipulated variable from a deviation between a setpoint variable and a control output variable and then using said manipulated variable, said method comprising the steps of:

• performing frequency analysis on time series data of said control output variable;
• determining a range of periods within which a substantive function is positive, wherein said substantive function is a function of frequency and whose sign is same as that of said rate of change;
• and
• increasing control gain by a given value when maximum value of an amplitude obtained by decomposing said time series data within said range of periods into frequency components is larger than a first value, or decreasing said control gain by a given value when said maximum value is smaller than a second value.

An adaptive control apparatus for controlling a process by calculating a manipulated variable from a deviation between a setpoint variable and a control output variable and then using said manipulated variable, said apparatus comprising:

• means for performing frequency analysis on time series data of said control output variable;
• means for determining a range of periods within which either rate of change in frequency response amplitude of said control output variable in relation to a control gain ratio or a substantive function, is positive, wherein said substantive function is a function of frequency and whose sign is same as that of said rate of change;
• and
• means for increasing control gain by a given value when maximum value of an amplitude obtained by decomposing said time series data within said range of periods into frequency components is larger than a first value, or decreasing said control gain by a given value when said maximum value is smaller than a second value.