Control system for plant

Abstract

A control system for a plant which controls the plant using an identifier and a sliding mode controller. The identifier identifies a model parameter vector of a controlled object model of the plant. The sliding mode controller controls the plant using the model parameter vector identified by the identifier. According to the identifier, an identifying error of the model parameter vector is calculated and an updating vector is calculated according to the identifying error. The updating vector is corrected by multiplying a past value of at least one element of the updating vector by a predetermined value which is greater than “0” and less than “1”. The model parameter vector is calculated by adding the corrected updating vector to a reference vector of the model parameter vector.

What is claimed is:  
     
         1 . A control system for a plant, comprising: 
 identifying means for identifying a model parameter vector of a controlled object model which is obtained by modeling said plant, based on an input and an output of said plant; and    a sliding mode controller for controlling said plant using the model parameter vector identified by said identifying means;    said identifying means comprising: 
 identifying error calculating means for calculating an identifying error of the model parameter vector;  
 updating vector calculating means for calculating an updating vector according to said identifying error; and  
 updating vector correcting means for correcting said updating vector by multiplying a past value of at least one element of said updating vector by a predetermined value which is greater than 0 and less than 1;  
 wherein said identifying means calculates the model parameter vector by adding the corrected updating vector to a reference vector of the model parameter vector.  
   
     
     
         2 . A control system according to  claim 1 , wherein said updating vector correcting means does not multiply one of an element of the updating vector which is relevant to the input of said plant and an element of the updating vector which is irrelevant to the input and the output of said plant, by the predetermined value.  
     
     
         3 . A control system according to  claim 1 , wherein said updating vector correcting means multiplies at least one element of the reference vector by the predetermined value.  
     
     
         4 . A control system according to  claim 1 , wherein said identifying means identifies the model parameter vector using a fixed gain algorithm.  
     
     
         5 . A control system according to  claim 1 , wherein said identifying error calculating means performs a low-pass filtering of the identifying error and outputs the identifying error after the low-pass filtering.  
     
     
         6 . A control system according to  claim 1 , further comprising predicting means for calculating a predicted value of the output of said plant, wherein said sliding mode controller uses the calculated predicted value.  
     
     
         7 . A control system according to  claim 6 , wherein said predicting means calculates the predicted value using the model parameter vector identified by said identifying means.  
     
     
         8 . A control system according to  claim 1 , wherein a control input applied from said sliding mode controller to said plant includes an adaptive law input.  
     
     
         9 . A control system according to  claim 1 , wherein said plant includes a throttle valve actuating device having a throttle valve of an internal combustion engine and actuating means for actuating said throttle valve, and said sliding mode controller calculates a parameter for determining a control input to be applied to said throttle valve actuating device to make the opening of said throttle valve coincide with a target opening.  
     
     
         10 . A control system for a plant, comprising: 
 identifying means for identifying a model parameter vector of a controlled object model which is obtained by modeling said plant, based on an input and an output of said plant; and    a sliding mode controller for controlling said plant using the model parameter vector identified by said identifying means;    said identifying means comprising: 
 identifying error calculating means for calculating an identifying error of the model parameter vector; and  
 identifying error correcting means for correcting the identifying error in a decreasing direction, if the identifying error is in a predetermined range;  
 wherein said identifying means calculates the model parameter vector using the identifying error corrected by said identifying error correcting means.  
   
     
     
         11 . A control system according to  claim 10 , wherein said identifying error correcting means sets the identifying error to “0”, if the identifying error is in the predetermined range.  
     
     
         12 . A control system according to  claim 10 , wherein the predetermined range is set according to an amount of change in a control target value or an amount of change in the output of said plant.  
     
     
         13 . A control system according to  claim 10 , further comprising predicting means for calculating a predicted value of the output of said plant, wherein said sliding mode controller uses the calculated predicted value.  
     
     
         14 . A control system according to  claim 13 , wherein said predicting means calculates the predicted value using the model parameter vector identified by said identifying means.  
     
     
         15 . A control system according to  claim 10 , wherein said plant includes a throttle valve actuating device having a throttle valve of an internal combustion engine and actuating means for actuating said throttle valve, and said sliding mode controller calculates a parameter for determining a control input to be applied to said throttle valve actuating device to make the opening of said throttle valve coincide with a target opening.  
     
     
         16 . A control method for a plant, comprising the steps of: 
 a) identifying a model parameter vector of a controlled object model which is obtained by modeling said plant, based on an input and an output of said plant; and    b) controlling said plant with a sliding mode control using the identified model parameter vector;    said step a) of identifying the model parameter vector, comprising the steps of: 
 i) calculating an identifying error of the model parameter vector;  
 ii) calculating an updating vector according to said identifying error; and  
 iii) correcting the updating vector by multiplying a past value of at least one element of the updating vector by a predetermined value which is greater than 0 and less than 1;  
 wherein the model parameter vector is calculated by adding the corrected updating vector to a reference vector of the model parameter vector.  
   
     
     
         17 . A control method according to  claim 16 , wherein one of an element of the updating vector which is relevant to the input of said plant and an element of the updating vector which is irrelevant to the input and the output of said plant, is not multiplied by the predetermined value.  
     
     
         18 . A control method according to  claim 16 , wherein at least one element of the reference vector is multiplied by the predetermined value.  
     
     
         19 . A control method according to  claim 16 , wherein the model parameter vector is identified using a fixed gain algorithm.  
     
     
         20 . A control method according to  claim 16 , wherein a low-pass filtering of the identifying error is performed and the identifying error after the low-pass filtering is used in the calculation of the updating vector.  
     
     
         21 . A control method according to  claim 16 , further comprising the step of calculating a predicted value of the output of said plant, wherein the calculated predicted value is used in controlling said plant with the sliding mode control.  
     
     
         22 . A control method according to  claim 21 , wherein the predicted value is calculated using the identified model parameter vector.  
     
     
         23 . A control method according to  claim 16 , wherein a control input applied to said plant in said step b) includes an adaptive law input.  
     
     
         24 . A control method according to  claim 16 , wherein said plant includes a throttle valve actuating device having a throttle valve of an internal combustion engine and actuating means for actuating said throttle valve, and a parameter for determining a control input to be applied to said throttle valve actuating device is calculated in said step b) to make the opening of said throttle valve coincide with a target opening.  
     
     
         25 . A control method for a plant, comprising the steps of: 
 a) identifying a model parameter vector of a controlled object model which is obtained by modeling said plant, based on an input and an output of said plant; and    b) controlling said plant with a sliding mode control using the model parameter vector identified by said identifying means;    said step a) comprising the steps of: 
 i) calculating an identifying error of the model parameter vector; and  
 ii) correcting the identifying error in a decreasing direction, if the identifying error is in a predetermined range;  
 wherein the model parameter vector is calculated using the corrected identifying error.  
   
     
     
         26 . A control method according to  claim 25 , wherein the identifying error is set to “0”, if the identifying error is in the predetermined range.  
     
     
         27 . A control method according to  claim 25 , wherein the predetermined range is set according to an amount of change in a control target value or an amount of change in the output of said plant.  
     
     
         28 . A control method according to  claim 25 , further comprising the step of calculating a predicted value of the output of said plant, wherein the calculated predicted value is used in controlling said plant with the sliding mode control.  
     
     
         29 . A control method according to  claim 28 , wherein the predicted value is calculated using the identified model parameter vector.  
     
     
         30 . A control method according to  claim 25 , wherein said plant includes a throttle valve actuating device having a throttle valve of an internal combustion engine and actuating means for actuating said throttle valve, and a parameter for determining a control input to be applied to said throttle valve actuating device is calculated in said step b) to make the opening of said throttle valve coincide with a target opening.  
     
     
         31 . A control system for a plant, comprising: 
 an identifying module for identifying a model parameter vector of a controlled object model which is obtained by modeling said plant, based on an input and an output of said plant; and    a sliding mode controller for controlling said plant using the model parameter vector identified by said identifying module;    said identifying module comprising: 
 an identifying error calculating module for calculating an identifying error of the model parameter vector;  
 an updating vector calculating module for calculating an updating vector according to said identifying error; and  
 an updating vector correcting module for correcting said updating vector by multiplying a past value of at least one element of said updating vector by a predetermined value which is greater than 0 and less than 1;  
 wherein said identifying module calculates the model parameter vector by adding the corrected updating vector to a reference vector of the model parameter vector.  
   
     
     
         32 . A control system according to  claim 31 , wherein said updating vector correcting module does not multiply one of an element of the updating vector which is relevant to the input of said plant and an element of the updating vector which is irrelevant to the input and the output of said plant, by the predetermined value.  
     
     
         33 . A control system according to  claim 31 , wherein said updating vector correcting module multiplies at least one element of the reference vector by the predetermined value.  
     
     
         34 . A control system according to  claim 31 , wherein said identifying module identifies the model parameter vector using a fixed gain algorithm.  
     
     
         35 . A control system according to  claim 31 , wherein said identifying error calculating module performs a low-pass filtering of the identifying error and outputs the identifying error after the low-pass filtering.  
     
     
         36 . A control system according to  claim 31 , further comprising predicting module for calculating a predicted value of the output of said plant, wherein said sliding mode controller uses the calculated predicted value.  
     
     
         37 . A control system according to  claim 36 , wherein said predicting module calculates the predicted value using the model parameter vector identified by said identifying module.  
     
     
         38 . A control system according to  claim 31 , wherein a control input applied from said sliding mode controller to said plant includes an adaptive law input.  
     
     
         39 . A control system according to  claim 31 , wherein said plant includes a throttle valve actuating device having a throttle valve of an internal combustion engine and actuating module for actuating said throttle valve, and said sliding mode controller calculates a parameter for determining a control input to be applied to said throttle valve actuating device to make the opening of said throttle valve coincide with a target opening.  
     
     
         40 . A control system for a plant, comprising: 
 an identifying module for identifying a model parameter vector of a controlled object model which is obtained by modeling said plant, based on an input and an output of said plant; and    a sliding mode controller for controlling said plant using the model parameter vector identified by said identifying module;    said identifying module comprising: 
 an identifying error calculating module for calculating an identifying error of the model parameter vector; and  
 an identifying error correcting module for correcting the identifying error in a decreasing direction, if the identifying error is in a predetermined range;  
 wherein said identifying module calculates the model parameter vector using the identifying error corrected by said identifying error correcting module.  
   
     
     
         41 . A control system according to  claim 40 , wherein said identifying error correcting module sets the identifying error to “0”, if the identifying error is in the predetermined range.  
     
     
         42 . A control system according to  claim 40 , wherein the predetermined range is set according to an amount of change in a control target value or an amount of change in the output of said plant.  
     
     
         43 . A control system according to  claim 40 , further comprising predicting module for calculating a predicted value of the output of said plant, wherein said sliding mode controller uses the calculated predicted value.  
     
     
         44 . A control system according to  claim 43 , wherein said predicting module calculates the predicted value using the model parameter vector identified by said identifying module.  
     
     
         45 . A control system according to  claim 40 , wherein said plant includes a throttle valve actuating device having a throttle valve of an internal combustion engine and actuating module for actuating said throttle valve, and said sliding mode controller calculates a parameter for determining a control input to be applied to said throttle valve actuating device to make the opening of said throttle valve coincide with a target opening.