Kiln thermal and combustion control
View Patent ↗A kiln thermal and combustion control. A predictive model is provided of the dynamics of selected aspects of the operation of the system for modeling the dynamics thereof. The model has at least two discrete models associated therewith that model at least two of the selected aspects, the at least two discrete models having different dynamic responses. An optimizer receives desired values for the selected aspects of the operation of the system modeled by the model and optimizes the inputs to the model to minimize error between the predicted and desired values. A control input device then applies the optimized input values to the system after optimization thereof.
1. A controller for controlling a multi-variable input system having a plurality of manipulatible variables (MVs) as inputs, and operable to provide a plurality of measurable outputs and at least one unmeasurable output, which unmeasurable output can not be measured in substantially real time and requires external analysis for the determination of parameters thereof, comprising:
a system predictive model that provides a model of the dynamics of selected aspects of the operation of the system for modeling the dynamics thereof and providing at least one predicted output for at least a select one of the measurable outputs;
an external predictive model for predicting as a predicted control value the dynamic response of a select one of the measurable outputs as a function of the at least one unmeasurable output to achieve a desired value of the at least one unmeasurable output;
an optimizer for receiving desired values for the selected aspects of the operation of the system modeled by said system predictive model and said predicted outputs from said system predictive model and optimizing the inputs to the predictive model to minimize error between the predicted and desired values; and
a control input device for applying the predicted control value to the system and the optimized input values to the system after optimization thereof, wherein a change in the select one of the unmeasuruble outputs is not accounted for in the control input device.
2. The controller of claim 1 , wherein said optimizer is further operable to receive constraints on said input values such that the optimization operation changes the inputs within said constraints when minimizing the error between the predicted and desired values.
3. The controller of claim 1 , wherein the system is subject to at least one disturbance variable that alters the operation of the system and wherein said predictive model will predict the behavior of the selected aspects modeled thereby in response to changes in the at least one disturbance variable and said optimizer will change the inputs to again minimize the error between the predicted and desired values.
4. A method for controlling a multi-variable input system having a plurality of manipulatible variables (MVs) as inputs, and operable to provide a plurality of measurable outputs and at least one unmeasurable output, which unmeasurable output can not be measured in substantially real time and requires external analysis for the determination of parameters thereof, comprising the steps of:
providing a system predictive model that provides a model of the dynamics of selected aspects of the operation of the system for modeling the dynamics thereof and providing at least one predicted output for at least a select one of the measurable outputs;
providing an external predictive model for predicting as a predicted control value the dynamic response of a select one of the measurable outputs as a function of the at least one unmeasurable output parameter and the desired value for that at least one parameter to predict the dynamics as a desired value of the select one of the measurable outputs required to achieve a desired value of the at least one unmeasurable output;
receiving in an optimizer desired values for the selected aspects of the operation of the system modeled by the predictive model and the predicted outputs from the predictive model in addition to the desired value of the select one of the measurable outputs generated by the external predictive model and optimizing the inputs to the predictive model to minimize error between the predicted and desired values; and
applying the predicted control value to the system and the optimized input values to the system after optimization thereof, wherein a change in the select one of the unmeasurable outputs is not accounted for in the control input device.
5. The method of claim 4 , wherein the step of optimizing is further operable to receive constraints on the input values such that the optimization operation changes the inputs within the constraints when minimizing the error between the predicted and desired values.
6. The method of claim 4 , wherein the system is subject to at least one disturbance variable that alters the operation of the system and wherein the predictive model will predict the behavior of the selected aspects modeled thereby in response to changes in the at least one disturbance variable and the step of optimizing will change the inputs to again minimize the error between the predicted and desired values.
7. The controller of claim 1 , wherein said external predictive model comprises a linear model.
8. The controller of claim 1 , wherein the unmeasurable output comprises a product that is fabricated by the system.
9. The controller of claim 1 , wherein said optimizer is not operable to utilize said external predictive model during the operation thereof for the purpose of prediction therewith.
10. The method of claim 4 , wherein the external predictive model comprises a linear model.
11. The method of claim 4 , wherein the unmeasurable output comprises a product that is fabricated by the system.
12. The method of claim 4 , wherein the step of optimizing is not operable to utilize the external predictive model during the operation thereof for the purpose of prediction therewith.