Symbolization apparatus and process control system and control support system using the same apparatus

A process control system for detecting process conditions and producing control values based on said detected process conditions to thereby control a process system in target process conditions, comprising:

• means for detecting process conditions of said process control system during every moment of operation of said process system;
• memory means for storing said detected process conditions;
• means for sampling said process conditions stored in said memory means and for performing a sum-of-product calculation using fature extraction filters stored in a filter memory unit to obtain values indicating polynomial expansion coefficients;
• means for transforming said values indicating polynomial expansion coefficients in said process conditions into symbolic expressions in a form of fuzzy logic expressions indicating qualitative process conditions according to a membership function;
• knowledge base means for storing causal relations between said process conditions and process control values;
• combination network means for determining a combination of symbolic expressions according to said causal relations stored in said knowledge base means;
• symbol conversion means for receiving said combination of symbolic expressions from said combination network means and obtaining a weighted average of said combination of symbolic expressions as process control values using coupling weighting factors;
• and
• means for converting said process control values into control signals supplied to said process system.

A process control system for detecting process conditions and producing control values based on said detected process conditions to thereby control a process system in target process conditions, comprising:

• means for detecting process conditions of said process control system during every moement of operation of said process system;
• memory means for storing said detected process conditions;
• means for sampling said process conditions stored in said memory means and for performign a predetermined calculation using sampled process conditions to obtain values indicating levels and trends in said process conditions;
• means for transforming said values indicating levels and trends in said process conditions into symbolic expressions indicating qualitative process conditions according to a membership function;
• means for determining process control values by selecting process conditions close to desired conditions according to said symbolic expressions indicating qualitative process conditions;
• means for converting said process control values into control signals supplied to said process system
• wherein said determining means comprises:
• means for storing said symbolic expressions from said transforming means,
• knowledge base means for storing causal relations between said process conditions and said process control values,
• combination network means for determining combinations of said symbolic expressions according to said causal relations stored in said knowledge base means, and
• symbol conversion means for receiving said combinatinos of said symbolic expressions from said combination network means and for making weighted average of said symbolic expressions as said process control values using coupling weighing factors;
• means for storing history of said symbolic expressions from said transforming means and said process cotnrol values from said determining means;
• means for correcting said coupling weighing factors in said symbol conversion means according to said stored history of said symbolic expressions and said process control values by means of an error back propagation learning method;
• restoration means for restoring said symbolic expressions indicating qualitative process conditions to a time-series of data of the process in a form of polygonal line;
• display means for displaying said time-series of data;
• and
• model generation means for generating and expressing a model of said process system in a form of connecting state of the combination network by means of said causal relations stored in said knowledge base means, said model generation means having a structure identical to that of said determining means.

A process control system for detecting process conditions and producing control values based on said detected process conditions to thereby control a process system in target process conditions, comprising:

• means for detecting process conditions of said process control system during every moment of operation of said process system;
• memory means for storing said detected process conditions;
• means for sampling said process conditions stored in said memory means and for performing a predetermined calculation using sampled process conditions to obtain values indicating levels and trends in said process conditions;
• means for transforming said values indicating levels and trends in said process conditions into symbolic expressions indicating qualitative process conditions according to a membership function;
• means for determining process control values by selecting process conditions close to desired conditions according to said symbolic expressions indicating qualitative process conditions;
• means for converting said process control values into control signals supplied to said process system
• wherein said determining means comprises:
• means for storing said symbolic expressions from said transforming means,
• knowledge base means for storing causal relations between said process conditions and said process control values,
• combination network means for determining combinations of said symbolic expressions according to said causal relations stored in said knowledge base means, and
• symbol conversion means for receiving said combinations of said symbolic expressions from said combination network means and for making weighted average of said symbolic expressions as said process control values using coupling weighing factors;
• means for storing history of said symbolic expressions from said transforming means and said process control values from said determining means;
• means for correcting said coupling weighing factors in said symbol conversion means according to said stored history of said symbolic expressions and said process control values by means of an error back propagation learning method;
• means for inputting process control values by an operator;
• simulation means for simulating change of conditions of a simulation model of a process system;
• comparator unit for comparing said procesas conditions of said history in said history storing means with the result of said simulatino by said simulation means;
• and
• display means for displaying a comparison result from said comparator unit to display said result to said operator.

A process control system for detecting process conditions and producing control values based on said detected process conditions to thereby control a process system in target process conditions, comprising:

• means for detecting process conditions of said process control system during every moment of operation of said process system;
• memory means for storing said detected process conditions;
• means for sampling said process conditions stored in said memory means and for performing a predetermined calculation using sampled process conditions to obtain values indicating levels and trends in said process conditions;
• means for transforming said values indicating levels and trends in said process conditions into symbolic expressions indicating qualitative process conditions according to a membership function;
• means for determining process control values by selecting process conditions close to desired conditions according to said symbolic expressions indicating qualitative process conditions;
• means for converting said process control values into control signals supplied to said process system
• wherein said determining means comprises:
• means for storing said symbolic expressions from said transforming means,
• knowledge base means for storing causal relations between said process conditions and said process control values,
• combination network means for determining combinations of said symbolic expressions according to said causal relations stored in said knowledge base means, and
• symbol conversion means for receiving said combinations of said symbolic expressions from said combination network means and for making weighted average of said symbolic expressions as said process control values using coupling weighing factors;
• means for storing history of said symbolic expressions from said transforming means and said process control values from said determining means;
• means for correcting said coupling weighing factors in said symbol conversion means according to said stored history of said symbolic expressions and said process control values by means of an error back propagation learning method;
• searching means for searching for past symbolic expressions of said process conditions and said process control values in said history storing means to extract said symbolic expressions most similar to present symbolic expressions;
• and
• restoration means for restoring said symbolic expressions received from said searching means to a time-series of data of the process in a form of polygonal line.