RU2012030C1 - System of automatic regulation for objects with delayed operations - Google Patents

Abstract

FIELD: automatic control. SUBSTANCE: device has adders 1, 3, unit 2 for reverse simulation of inertial part of controlled object, correction unit 4, controlled object 5, delay unit 6. EFFECT: increased functional capabilities. 1 dwg

Description

 The invention relates to the field of automatic control of technological processes and can be used to control processes containing transport delay, mainly in control objects containing, in addition to the transport delay link, a high-order inertial link, as well as in cases when the dynamic error of the meter significantly affects the quality of regulation.

 Known regulators that use knowledge of the dynamics of the control object and the delay unit for the time of transport delay, for example, the Smith predictor [1], using a direct model of the object without delay and the delay unit. Using the Smith predictor, it is possible to obtain a better control quality than using typical industrial PID controllers. However, this quality of regulation is often insufficient.

 A slightly higher accuracy of regulation can be obtained using the Resvik regulator [2], which is the closest to the proposed technical solution. The Resvik controller uses the inverse dynamic model of the inertial part of the control object and a delay unit for the time of pure delay. The automatic control system using the Resvik controller includes a series-connected first adder, an inverse object model unit, a second adder and a control object, as well as a delay unit whose input is connected to the input of the control object. However, the accuracy of regulation in such a system and stability can be greatly reduced if the control object has a large order of inertia, and the meter has a significant dynamic error.

 The aim of the invention is to increase the accuracy of regulation and stability of the system, reducing its susceptibility to random meter error.

 The goal is achieved by the fact that in the automatic control system for objects with delay, containing in series the first adder, the inverse model unit of the object, the second adder, as well as the delay unit, the input of which is connected to the input of the control object, and the output - with the positive input of the second adder, an element with a rational transfer function has been introduced, the input of which is connected to the output of the second adder, and the output to the inputs of the delay unit and the control object.

 An element with a fractional rational transfer function can be a combination of typical links, determined by the nature of the object, input disturbances, and the random component of the meter error. Such an element makes it possible to best isolate and predict a useful signal against a background of noise.

 Although the use of elements with fractional rational transfer function in automatic control systems is known, however, in automatic control systems for objects containing transport delay, such elements have not been previously applied. Therefore, the proposed technical solution has "Novelty" and "Significant differences" in comparison with the known.

 The drawing shows a block diagram of an automatic control system for objects containing transport lag.

 It includes series-connected the first adder 1, block 2 of the inverse model of the inertial part of the control object 5, the second adder 3, the corrective link 4 with fractional rational transfer function, as well as the delay unit 6 for the time of the transport delay of the object. The input of the delay unit is connected to the output of the corrective link with a fractional rational transfer function, and the output to the positive input of the second adder.

 The automatic control system operates as follows.

, где S₂₀ = 1, Т₁ = 0,5 мин - константы.The control object is a first-order inertial object with a time constant Т _о = 2 min and a pure delay time τ = 2 min. At the input of the object serves "white noise" with an intensity of S ₁₀ = 100. The spectral density of the random error of the meter is set in the form
S ₂ (ω) =

where S ₂₀ = 1, T ₁ = 0.5 min are constants.

, где T =

- постоянная времени;
K =

e^-τ/T° - коэффициент усиления;
При описанных условиях Т = 0,54 мин, К = 0,22. Дисперсия отклонения выходной координаты системы от заданного значения составляет 69,9.The best transfer function of the corrective link 4 has the form
F (P) = K

where T =

- time constant;
K =

e- ^{τ / T} ° - gain;
Under the described conditions, T = 0.54 min, K = 0.22. The dispersion of the deviation of the output coordinate of the system from the set value is 69.9.

 If you use the Resvik controller (prototype) under the same conditions, then with its best setting, the dispersion is equal to 80.8.

 Thus, the proposed technical solution allows to obtain a higher accuracy of regulation compared to the prototype, namely to increase the accuracy by 15%, while the stability of regulation also increases.

Claims (1)

 AUTOMATIC CONTROL SYSTEM FOR OBJECTS WITH DELAY, containing the first adder in series, the first adder of which is the system input, the inverse model unit of the inertial part of the control object, the second adder, the second input of which is connected to the output of the delay unit, the input of which is connected to the input of the control object, the output which is connected to the second input of the first adder, characterized in that, in order to increase the accuracy of regulation, an additional corrective link is introduced from the fractional ration noy transfer function, the input of the correction element with a rational transfer function connected to the output of the second adder, and an output - to an input of the control object.