3-freedom uncoupling control system for chemical ring-opening non-stable tandem course

Abstract

The control system comprises a controller of given value response, a controller for stabilizing response of given value, disturbance observer, id models of astable process in controlled transtage and stable process in last stage, and signal mixer. Open loop control mode is adopted in given value response. Using proportion controller stabilizes astable cascading process. Amount of deviation between stabilized output of id model of process in transtage and actual output in transtage as well as amount of deviation between stabilized output of id model of global cascading astable process and actual output of process in last stage are utilized as feedback information for restraining interference signal of load in transtage and last stage. The disturbance observers in innerring and outer ring execute adjusting function. The control system can keep favorable robustness and stability, can adapt to modeling error of cascading processes and perturbation of procedural parameter in bigger range.

Description

Technical field: [0001] The invention relates to a three-degree-of-freedom decoupling control system for an open-loop unstable cascade process in chemical production. It is aimed at the open-loop unstable cascade process whose output can be measured in the intermediate stage in the chemical production. Based on robust control theory, a novel decoupling control system is proposed, which belongs to the field of industrial process control technology. Background technique: [0002] Unstable objects in the chemical process are difficult to control, especially for unstable processes with obvious time lag. The outstanding problem is that they are more sensitive to load interference and easily cause large fluctuations in process output, such as steam drum boilers, chemical continuous stirred reactors (CSTR) and thermal reactors in the energy industry. This situation is usually very unfavorable and harmful to actual production. Therefore, when it is possible to measure the output of the i...

AI Technical Summary

Problems solved by technology

Once the final performance index of the entire control system cannot meet the specified requirements, or the performance index of the control system decreases due to process parameter perturbation during system operation, the inner and outer loop controllers must be readjusted according to the above tuning steps. Therefore, whether it is pre-tuning the conventional cascade control system or adjusting the conventional cascade control system online is relatively cumbersome, and the performance of the control system obtained without careful tuning is not necessarily better than the classic single-loop control structure.

Especially for unstable processes, a very obvious water bed effect will appear when adjusting the setpoint response and load disturbance response at the same time (Kemin Zhou, Doyle, J.C. and Glove; K. Essentials of Robust Control. Prentice hall, Upper Saddle River, 1998.), the contradiction of trade-off is much sharper than that of open-loop stable process cascade control system

[0004] Therefore, in many practical industrial applications such as steam drum boilers, chemical continuous stirring reactors and pharmaceutical processes, engineers and actual users even give up the conventional cascade control structure after weighing the above-mentioned advantages and disadvantages and still adopt the classic single-loop control structure. The superiority of the cascade control structure has not been brought into full play in the actual applicable occasions and working conditions

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