CN107975519B - Servo hydraulic energy double-closed-loop control system and method - Google Patents
Servo hydraulic energy double-closed-loop control system and method Download PDFInfo
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- CN107975519B CN107975519B CN201610921926.3A CN201610921926A CN107975519B CN 107975519 B CN107975519 B CN 107975519B CN 201610921926 A CN201610921926 A CN 201610921926A CN 107975519 B CN107975519 B CN 107975519B
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Abstract
The invention belongs to the field of servo mechanism hydraulic energy control, and particularly relates to a servo hydraulic energy double-closed-loop control system and method. In the invention, input pressure P flows to a first PID controller through a first adder, the first flow of the PID controller is converted into a first pressure current signal, the first pressure current signal is converted and flows to a proportional overflow valve after passing through a second adder, the proportional overflow valve flows to a current sensor and a hydraulic loop, and output pressure P' of the hydraulic loop flows to the first adder after passing through the pressure sensor; the input pressure P flows to the pressure current signal to be converted into a second current I, the current I and the feedback current I' output by the current sensor flow to the PID controller II through the third adder, and the PID controller flows to the second adder. The invention can automatically switch between the pressure current double closed loop, the single pressure closed loop and the single current closed loop according to the working state of the hydraulic energy system, thereby improving the speed and the reliability of the control of the servo hydraulic energy system.
Description
Technical Field
The invention belongs to the field of servo mechanism hydraulic energy control, and particularly relates to a servo hydraulic energy double-closed-loop control system and method.
Background
The servo mechanism is a general name of the subsystem of the carrier rocket flight control actuating mechanism in China. The servo hydraulic energy is an important component of the servo mechanism, provides stable pressure output for the servo mechanism, and has the characteristics of high power, high response and the like. The servo hydraulic energy pressure is mainly adjusted and controlled by the opening of a proportional overflow valve, and the traditional control method comprises manual adjustment control and pressure feedback closed-loop automatic control. The pressure closed-loop automatic control feeds the energy pressure acquisition back to a computer or an embedded control system through a pressure sensor, and the energy pressure acquisition is processed by the computer or the embedded control system and then is subjected to signal conversion to adjust a proportional overflow valve until the energy pressure reaches a target value, so that the defects of manual adjustment and control are overcome, but the pressure closed-loop automatic control has the characteristics of low response speed and insufficient reliability in high-power and strong electromagnetic interference environments.
Disclosure of Invention
The technical problems solved by the invention are as follows: aiming at the defects of the prior art, the servo hydraulic energy double closed-loop control system and the method are provided, and automatic switching can be carried out among the pressure current double closed loop, the single pressure closed loop and the single current closed loop according to the working state of the hydraulic energy system, so that the control speed and the control reliability of the servo hydraulic energy system are improved.
The technical scheme adopted by the invention is as follows:
a servo hydraulic energy dual closed loop control system comprising: the system comprises a pressure sensor, a current sensor, a pressure current signal conversion I, a pressure current signal conversion II, a PID controller I, a PID controller II, a proportional overflow valve and a hydraulic loop; the input pressure P flows to a first PID controller through a first adder, the output quantity of the first PID controller flows to a first pressure current signal conversion, the output quantity of the first pressure current signal conversion flows to a proportional overflow valve after passing through a second adder, the proportional overflow valve is respectively connected with a current sensor and a hydraulic circuit, and the output pressure P' of the hydraulic circuit flows to the first adder after passing through the pressure sensor; the input pressure P flows to the pressure current signal to be converted into a second current I, the current I and the feedback current I' output by the current sensor flow to the PID controller II through the third adder, and the output quantity of the PID controller II flows to the second adder.
The pressure outer ring comprises a PID controller I, a pressure current signal conversion I, a proportional overflow valve, a hydraulic loop and a pressure sensor, wherein input pressure P is target pressure, the pressure sensor acquires current output pressure P ' to obtain feedback pressure P ', a deviation signal △ P obtained by the difference between P ' and the input pressure P is used as the input of the PID controller I, and the output of the PID controller I enters an adder through the pressure current signal conversion I.
The current inner ring comprises a pressure current signal conversion II, a PID controller II, a proportional overflow valve and a current sensor, input pressure P enters the pressure current conversion II to be converted into target current I, the current of the proportional overflow valve is collected through the current sensor, a deviation signal △ I obtained by the difference between feedback current I ', I' and the target current value I is obtained and serves as the input of the PID controller II, and the output of the PID controller II enters an adder;
a servo hydraulic energy double closed-loop control method comprises the following steps:
step 1, obtaining a conversion relation between input pressure P and proportional relief valve control current I through theoretical analysis or experiments, and using the conversion relation in pressure current signal conversion I and pressure current signal conversion II;
step 2, inputting pressure P, collecting a current pressure value through a pressure sensor at a pressure outer ring, collecting a current value of a proportional overflow valve through a current sensor at a current inner ring, judging the current working states of the pressure sensor and the current sensor, and selecting a control method;
step 3, providing a control strategy according to the control method obtained in the step 2;
and 4, after the output of the PID controller I is subjected to pressure current conversion and the output of the PID controller II is added by the adder, the output is input into a proportional overflow valve to adjust the opening degree of the proportional overflow valve, so that the pressure value of the hydraulic energy source is adjusted.
In the step 2, when the pressure sensor and the current sensor are normal, the whole hydraulic energy system adopts pressure current double closed-loop control; when the abnormal current sensor of the pressure sensor is normal, adopting independent current closed-loop control; when the normal current sensor of the pressure sensor is abnormal, the independent pressure closed-loop control is adopted.
In the step 3, when the pressure current double closed-loop control method is adopted, the pressure outer ring PID controller I adopts integral control, the pressure regulation precision is improved, the deviation is eliminated, and the transfer function is
Wherein KiTo integrate the gain, KiWith the piecewise strategy, the current inner loop PID controller uses a ratio that increases with decreasing offset signal △ PControl, increase the regulation rate, transfer function G2(s) ═ K; when using closed loops of individual currents, G1(s) is 0, the pressure outer ring closed-loop control function is closed, the PID controller keeps the current output quantity,
same KiWith a segmented strategy, increasing as the deviation signal △ I decreases, and when a single pressure closed loop is used, G2(s) is 0, the current inner loop closed-loop control function is closed, the PID controller II keeps the current output quantity,
same KiThe segmentation strategy is employed to increase as the deviation signal △ P decreases.
The invention has the beneficial effects that:
(1) according to the servo hydraulic energy double closed-loop control system and method, the current inner loop is introduced to implement double closed-loop control on the basis of pressure closed loop, so that the control reliability of the whole energy system, particularly a high-power hydraulic energy system, is effectively improved;
(2) according to the servo hydraulic energy double closed-loop control system and method provided by the invention, the controller adopts variable parameter PID control, the control precision is ensured, the control speed is increased, and the response speed requirement is better met;
(3) the servo hydraulic energy double closed-loop control system and the method provided by the invention are also suitable for the automatic control of four parameters of pressure, temperature, flow and liquid level in the field of industrial control.
Drawings
FIG. 1 is a schematic diagram of a servo hydraulic energy control system and method.
Detailed Description
The servo hydraulic energy source double closed-loop control system and method provided by the invention are further described in detail with reference to the accompanying drawings and specific embodiments.
As shown in fig. 1, the present invention provides a servo hydraulic energy dual closed-loop control system, which includes: the system comprises a pressure sensor, a current sensor, a pressure current signal conversion I, a pressure current signal conversion II, a PID controller I, a PID controller II, a proportional overflow valve and a hydraulic loop;
the input pressure P flows to a first PID controller through a first adder, the output quantity of the first PID controller flows to a first pressure current signal conversion, the output quantity of the first pressure current signal conversion flows to a proportional overflow valve after passing through a second adder, the proportional overflow valve is respectively connected with a current sensor and a hydraulic circuit, and the output pressure P' of the hydraulic circuit flows to the first adder after passing through the pressure sensor; the input pressure P flows to the pressure current signal to be converted into a second current I, the current I and the feedback current I' output by the current sensor flow to the PID controller II through the third adder, and the output quantity of the PID controller II flows to the second adder.
The pressure outer ring comprises a PID controller I, a pressure current signal conversion I, a proportional overflow valve, a hydraulic loop and a pressure sensor, wherein the input pressure P is a target pressure, the pressure sensor acquires the current output pressure P ' to obtain a feedback pressure P ', a deviation signal △ P obtained by the difference between the P ' and the input pressure P is used as the input of the PID controller I, and the output of the PID controller I enters an adder through the pressure current signal conversion I;
the current inner ring comprises a pressure current signal conversion II, a PID controller II, a proportional overflow valve and a current sensor, input pressure P enters the pressure current conversion II to be converted into target current I, the current of the proportional overflow valve is collected through the current sensor, a deviation signal △ I obtained by the difference between feedback current I ', I' and the target current I is obtained and serves as the input of the PID controller II, and the output of the PID controller II enters an adder;
the output I of the adder is always used as the input of the proportional overflow valve, and the output of the proportional overflow valve is used as the input of the hydraulic circuit.
A servo hydraulic energy double closed-loop control method comprises the following steps:
step 1, obtaining a conversion relation between input pressure P and proportional relief valve control current I through theoretical analysis or experiments, and using the conversion relation in pressure current signal conversion I and pressure current signal conversion II;
step 2, inputting pressure P, collecting a current pressure value through a pressure sensor on a pressure outer ring, collecting a current value of a proportional overflow valve through a current sensor on a current inner ring, judging the current working states of the pressure sensor and the current sensor, and controlling the whole hydraulic energy system by adopting a pressure current double closed loop when the pressure sensor and the current sensor are normal; when the abnormal current sensor of the pressure sensor is normal, adopting independent current closed-loop control; when the normal current sensor of the pressure sensor is abnormal, adopting independent pressure closed-loop control;
step 3, the specific control method in this example: when the pressure current double closed-loop control method is adopted, the first pressure outer-loop PID controller adopts integral control, the pressure regulation precision is improved, the deviation is eliminated, and the transfer function is
Wherein KiTo integrate the gain, KiBy adopting a segmentation strategy, the deviation signal △ P is reduced and increased, the current inner loop PID controller II adopts proportional control, the regulation rate is improved, and the transfer function G is improved2(s) ═ K. When using closed loops of individual currents, G1And(s) is equal to 0, the pressure outer ring closed-loop control function is closed, the PID controller I1 keeps the current output quantity,
same KiWith a segmented strategy, increasing as the deviation signal △ I decreases, when a single pressure closed loop is used, G2(s) is 0, the current inner loop closed-loop control function is closed, the PID controller II keeps the current output quantity,
same KiThe proportional regulation P has the advantages of high response speed and quick regulation, the integral regulation I can eliminate residual error, the differential regulation D can change according to the deviation signal and act in advance, and in the engineering practice, a proper PID control strategy can be selected according to the actual system condition。
And 4, after the output of the PID controller I is subjected to pressure current conversion and the output of the PID controller II is added by the adder, the output is input into a proportional overflow valve to adjust the opening degree of the proportional overflow valve, so that the pressure value of the hydraulic energy source is adjusted.
Claims (6)
1. A servo hydraulic energy double closed-loop control system is characterized in that: the method comprises the following steps: the system comprises a pressure sensor, a current sensor, a pressure current signal conversion I, a pressure current signal conversion II, a PID controller I, a PID controller II, a proportional overflow valve and a hydraulic loop; the input pressure P flows to a first PID controller through a first adder, the output quantity of the first PID controller flows to a first pressure current signal conversion, the output quantity of the first pressure current signal conversion flows to a proportional overflow valve after passing through a second adder, the proportional overflow valve is respectively connected with a current sensor and a hydraulic circuit, and the output pressure P' of the hydraulic circuit flows to the first adder after passing through the pressure sensor; the input pressure P flows to the pressure current signal to be converted into a second current I, the current I and the feedback current I' output by the current sensor flow to the PID controller II through the third adder, and the output quantity of the PID controller II flows to the second adder.
2. The servo hydraulic energy double closed-loop control system according to claim 1, characterized in that a pressure outer ring comprises a PID controller I, a pressure current signal conversion I, a proportional overflow valve, a hydraulic loop and a pressure sensor, wherein an input pressure P is a target pressure, the pressure sensor acquires a current output pressure P ' to obtain a feedback pressure P ', a deviation signal △ P obtained by the difference between the P ' and the input pressure P is used as the input of the PID controller I, and the output of the PID controller I is converted into an adder through the pressure current signal conversion I.
3. The servo hydraulic energy double closed-loop control system according to claim 1, characterized in that the current inner loop comprises a pressure current signal conversion II, a PID controller II, a proportional overflow valve and a current sensor, input pressure P enters the pressure current signal conversion II to become target current I, the current sensor collects current of the proportional overflow valve to obtain a feedback current I ', a deviation signal △ I obtained by the difference between the I' and the target current I is used as the input of the PID controller II, and the output of the PID controller II enters the adder.
4. A servo hydraulic energy double closed-loop control method is characterized in that: according to a servo hydraulic energy source double closed loop control system, comprising: the system comprises a pressure sensor, a current sensor, a pressure current signal conversion I, a pressure current signal conversion II, a PID controller I, a PID controller II, a proportional overflow valve and a hydraulic loop; the input pressure P flows to a first PID controller through a first adder, the output quantity of the first PID controller flows to a first pressure current signal conversion, the output quantity of the first pressure current signal conversion flows to a proportional overflow valve after passing through a second adder, the proportional overflow valve is respectively connected with a current sensor and a hydraulic circuit, and the output pressure P' of the hydraulic circuit flows to the first adder after passing through the pressure sensor; the input pressure P flows to the pressure current signal conversion II to obtain a current I, the current I and the feedback current I' output by the current sensor flow to the PID controller II through the third adder, and the output quantity of the PID controller II flows to the second adder;
the method comprises the following steps:
the method comprises the following steps that (1) theoretical analysis or experiments are carried out to obtain a conversion relation between input pressure P and proportional relief valve control current Itotal, and the conversion relation is used for pressure current signal conversion I and pressure current signal conversion II;
step (2), inputting pressure P, collecting a current pressure value through a pressure sensor on a pressure outer ring, collecting a current value of a proportional overflow valve through a current sensor on a current inner ring, judging the current working states of the pressure sensor and the current sensor, and selecting a control method;
step (3), a control strategy is proposed according to the control method obtained in the step (2);
and (4) after the adder adds the output of the PID controller I and the output of the PID controller II through pressure current conversion, inputting the output of the PID controller I into a proportional overflow valve to adjust the opening degree of the proportional overflow valve, and adjusting the pressure value of the hydraulic energy.
5. The servo hydraulic energy source double closed-loop control method according to claim 4, characterized in that: in the step (2), when the pressure sensor and the current sensor are normal, the whole hydraulic energy system adopts pressure current double closed-loop control; when the abnormal current sensor of the pressure sensor is normal, adopting independent current closed-loop control; when the normal current sensor of the pressure sensor is abnormal, the independent pressure closed-loop control is adopted.
6. The servo hydraulic energy source double closed-loop control method according to claim 5, characterized in that: in the step (3), when the pressure current double closed-loop control method is adopted, the pressure outer ring PID controller I adopts integral control, the pressure regulation precision is improved, the deviation is eliminated, and the transfer function is
Wherein Ki is integral gain, Ki adopts a segmentation strategy, the Ki is increased along with the reduction of the deviation signal △ P, the current inner loop PID controller II adopts proportional control to improve the regulation rate, the transfer function G2(s) is K, when a single current closed loop is adopted, G1(s) is 0, the pressure outer loop closed loop control function is closed, the PID controller keeps the current output quantity,
similarly, Ki is increased along with the reduction of the deviation signal △ I by adopting a segmentation strategy, when the single pressure closed loop is adopted, G2(s) is 0, the current inner loop closed loop control function is closed, the PID controller II maintains the current output quantity,
also Ki is segmented and increases as the deviation signal △ P decreases.
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