阅读说明：本技术 一种改进型双闭环直流调速系统的控制方法 (Control method of improved double closed-loop direct current speed regulation system ) 是由 张鹏 朱呈祥 邓斌 邱守星 于 2019-09-16 设计创作，主要内容包括：一种改进型双闭环直流调速系统的控制方法,包括,首先确定速度环中所用模糊控制器类型,根据所确定的类型对控制器的输入、输出量进行模糊化,然后利用专家的知识和经验制定模糊规则并对相关量进行模糊推理,再通过重心法对输出量进行去模糊化得到最终输出量。本发明对传统双闭环直流调速系统存在控制精度低、抗干扰性差等缺陷,在转速环一节采用模糊PI控制器,设计出一种基于模糊控制的改进型双闭环直流调速系统的控制策略。本发明的效果在于：大大降低了双闭环直流调速系统静态误差,提高了控制精度,并使系统具有更强的抗干扰性和鲁棒性。(A control method of an improved double closed-loop direct current speed regulation system comprises the steps of firstly determining the type of a fuzzy controller used in a speed loop, fuzzifying the input quantity and the output quantity of the controller according to the determined type, then making a fuzzy rule by using expert knowledge and experience, carrying out fuzzy reasoning on related quantities, and then carrying out defuzzification on the output quantity by a gravity center method to obtain the final output quantity. The invention designs a control strategy of an improved double closed-loop direct current speed regulating system based on fuzzy control by adopting a fuzzy PI controller in a section of a rotating speed loop for the defects of low control precision, poor anti-interference performance and the like of the traditional double closed-loop direct current speed regulating system. The invention has the following effects: the static error of the double closed-loop direct current speed regulation system is greatly reduced, the control precision is improved, and the system has stronger anti-interference performance and robustness.)

1. A control method of an improved double closed loop direct current speed regulation system is characterized by comprising the following steps:

(1) determining the structure type of the fuzzy controller in the speed ring according to the structure block diagram of the fuzzy controller, and determining the input quantity and the output quantity of the controller;

(2) Defining fuzzy subsets of the input and output quantities of the fuzzy controller, and quantizing the fuzzy subsets to a specific domain of discourse;

(3) establishing a membership function of the fuzzy subset;

(4) Making a corresponding fuzzy rule table according to the knowledge and experience of experts, writing fuzzy control rule sentences item by item in the form of 'If condition and Then result' according to the content of the rule table, and selecting the most common Mamdain inference as a fuzzy inference method to obtain fuzzy output quantity;

(5) And defuzzifying the fuzzy output quantity to obtain a clear quantity for control.

2. the control method of the improved double closed-loop direct current speed regulation system as claimed in claim 1, wherein in the step (1), the fuzzy controller is a two-dimensional Mamdain type fuzzy controller, the deviation e and the deviation change rate ec of the actual rotating speed and the given rotating speed are used as input variables, and the proportional coefficient change quantity Δ K is used as an input variable_pOr the variation Δ K of the integral coefficient_iAs an output.

3. the control method of the improved double closed-loop direct current speed regulation system as claimed in claim 1, wherein in step (2), a proper discourse domain is selected for the input quantity and the output quantity, and the fuzzy subset defined by the input quantity and the output quantity is quantized to the selected discourse domain.

4. The control method of the improved double closed-loop direct current speed regulation system as claimed in claim 1, wherein in the step (5), an area equal division method is adopted, and the increment delta K can be obtained by the method_pAnd Δ K_ithe two quantities are respectively proportional to the initial proportionality coefficient K_pAnd integral coefficient K_iAnd adding the obtained product to obtain the final proportional coefficient and integral coefficient.

Technical Field

the invention relates to automatic control, in particular to a control method of an improved double closed-loop direct current speed regulating system.

Background

In the development of modern industry, the speed regulating system of the direct current motor is widely applied to electric traction due to good speed regulating, starting and braking effects of the speed regulating system. The speed regulating system of the direct current motor is generally designed into a double closed loop system, namely a double loop system of a rotating speed loop and a current loop, and the two loops are respectively controlled by a speed regulator and a current regulator. When the speed of the dc motor is adjusted, the design of the controller is often critical to achieve high dynamic and static control performance. The controller with good performance plays an important role in optimizing overshoot and reducing the static error rate, and is beneficial to prolonging the service life of the motor.

in a traditional strategy, a controller in a double-closed-loop direct-current speed regulation system usually adopts a conventional PI controller, the controller is simple in structure and convenient to implement, but a motor has the characteristic of nonlinearity, and when the dragging load of the motor suddenly changes or elastically changes, the conventional PI controller is often difficult to meet the requirements of high-performance and high-precision occasions. In order to solve the above problems, most researchers have conducted a combination of intelligent algorithm strategies with conventional industrial production. For example, expert rules are combined with PIDs, fish swarm algorithms are combined with PIDs, and so on.

the method for controlling the double closed loop direct current speed regulation in the current industrial production mainly comprises the following steps:

1. Conventional PI controllers: the two loops are matched with a conventional PI controller for speed regulation control, the control strategy has a simple structure and is convenient to implement, and the control strategy has the defects that the control strategy cannot be suitable for a system with a large model parameter change range and a strong nonlinear link of a controlled object.

2. An expert rule PI controller: an expert rule algorithm is added in the conventional PI control, the control strategy can carry out parameter on-line self-tuning along with a controlled object, and the control strategy has certain intelligent capability and has the defect that the control strategy is troublesome to be suitable for the design of a specific model and an expert rule base.

Disclosure of Invention

The invention aims to design a control strategy of an improved double closed-loop direct current speed regulating system by combining a fuzzy algorithm and a conventional PI controller aiming at the defects of the traditional controller.

in order to achieve the above purpose, the technical scheme of the invention is as follows:

A control method of an improved double closed loop direct current speed regulation system comprises the following steps:

(1) Determining the structure type of the fuzzy controller in the speed ring according to the structure block diagram of the fuzzy controller, and determining the input quantity and the output quantity of the controller;

(2) Defining fuzzy subsets of the input and output quantities of the fuzzy controller, and quantizing the fuzzy subsets to a specific domain of discourse;

(3) Establishing a membership function of the fuzzy subset;

(4) making a corresponding fuzzy rule table according to the knowledge and experience of experts, writing fuzzy control rule sentences item by item in the form of 'If condition and Then result' according to the content of the rule table, and selecting the most common Mamdain inference as a fuzzy inference method to obtain fuzzy output quantity;

(5) And defuzzifying the fuzzy output quantity to obtain a clear quantity for control.

Further, in the step (1), the fuzzy controller is of a two-dimensional Mamdain type fuzzy controller, the deviation e and the deviation change rate ec of the actual rotating speed and the given rotating speed are used as input variables, and the proportional coefficient change quantity delta K is used_pOr the variation Δ K of the integral coefficient_iAs an output.

further, in step (2), a proper domain is selected for the input and output quantities, and the fuzzy subset defined by the input and output quantities is quantized to the selected domain.

Further, in the step (5), the increment Δ K can be obtained by using an area equipartition method_pAnd Δ K_iThe two quantities are respectively proportional to the initial proportionality coefficient K_pand integral coefficient K_iAnd adding the obtained product to obtain the final proportional coefficient and integral coefficient.

compared with the prior art, the invention has the beneficial effects that:

According to the control method of the improved double closed-loop direct current speed regulation system, the fuzzy rule PI controller is designed by adopting a method of combining the fuzzy algorithm and the conventional PID control, the overshoot of the system can be reduced in the system by the controller, the regulation precision and the anti-interference performance of the system are improved, and the defects of poor dynamic and static performances, low robustness and the like of the traditional control strategy are overcome.

Drawings

FIG. 1 is a block diagram of the fuzzy controller architecture of the present invention;

FIG. 2 is a specific block diagram of a dual fuzzy controller in an embodiment of the present invention;

FIG. 3 is a schematic diagram of an idealized load simulation of an improved control strategy and a conventional control strategy in an embodiment of the present invention;

FIG. 4 is a simulation of loading disturbances for the improved control strategy and the conventional control strategy according to an embodiment of the present invention.

The specific implementation mode is as follows:

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.