CN102141172B - Device and method for identifying parameter of actuating mechanism in electrohydraulic linear displacement servo system - Google Patents

Abstract

The invention discloses a device and a method for identifying the parameter of an actuating mechanism in an electrohydraulic linear displacement servo system. The identification device consists of a step current signal generator, an electrohydraulic servo valve, a hydraulic cylinder, a mechanical load, a linear displacement detection sensor, a recording instrument and a hydraulic source. The identification method comprises the following steps of: inputting a step current signal into the electrohydraulic servo valve; recording the variation processes of a step current signal amplitude value and a linear displacement signal along with time variation until a straight ascension stage is reached; intersecting a straight line with a time axis along the straight ascension stage; measuring the slope of the straight line and the intercept value of the straight line intersected with the time axis; dividing the step current signal amplitude value by the slope of the straight line to acquire the equivalent viscous damping coefficient of the actuating mechanism; and multiplying the equivalent viscous damping coefficient by the intercept value to acquire the equivalent mass of the actuating mechanism. By the device and the method, the parameter of a controller of the electrohydraulic linear displacement servo system can be purposefully adjusted, and high static and dynamic properties can be acquired by the servo system.

Description

Actuator's parameter recognition device and identifying method in the electricity liquidus displacement servo-system

One. technical field:

The present invention relates to a kind of electro hydraulic servo system design method, more particularly, relate to actuator's parameter recognition device and identifying method in a kind of electric liquidus displacement servo-system.

Two. background technique:

Electricity liquidus displacement servo-system is widely used in departments such as industry, traffic, scientific research.In order to obtain good linear displacement servo performance, electric liquidus displacement servo-system must adopt closed loop control.Electricity liquidus displacement servo-system comprises electronic controller, actuator, linear displacement detecting sensor and hydraulic power.Wherein actuator by electrohydraulic control, oil hydraulic cylinder and it with mechanical load form.Have only actuator is carried out qualitative identification, could determine which type of electronic controller of design, have only the parameter of actuator is quantitatively discerned, could accurately adjust the Control Parameter of electronic controller.

At present, electric liquidus displacement servo-system electronic controller of the prior art, its Control Parameter is not to adjust according to the parameter of actuator, but directly adopts the Control Parameter of trial and error method or empirical method adjustment electronic controller.This just causes the Control Parameter adjustment of electronic controller to compare blindly, and the debugging of electric liquidus displacement servo-system is wasted time and energy, and the linear displacement servo performance is difficult to engineering demands.Therefore, when electric liquidus displacement Servo System Design and debugging, how discerning the parameter of actuator, then is that problem to be solved is arranged in the existing technology.

Three. summary of the invention:

The objective of the invention is to the problem that exists in the above-mentioned existing technology; Actuator's parameter recognition device and identifying method in a kind of electric liquidus displacement servo-system is provided; When making electric liquidus displacement Servo System Design, adjust the parameter of electronic controller with a definite target in view with debugging.

Electricity liquidus displacement servo-system comprises electronic controller, actuator, linear displacement detecting sensor and hydraulic power.Wherein actuator by electrohydraulic control, oil hydraulic cylinder and it with mechanical load form.Electrohydraulic control is the crux device of electric liquidus displacement servo-system; In electrohydraulic servo system, place switching place of electrical signal and hydraulic pressure signal; It at first converts the current signal of electronic controller output to the displacement of spool; And then convert the load flow in the hydraulic system again to, and be enlarged into the piston that large-power hydraulic can promote oil hydraulic cylinder and do linear motion, thereby drive the mechanical load work done.

Actuator by electrohydraulic control, oil hydraulic cylinder and it with mechanical load form.In the electricity liquidus displacement servo-system, during to the electrohydraulic control input current, be output as hydraulic cylinder piston and with the linear displacement of mechanical load.Therefore, be output as hydraulic cylinder piston and with the linear displacement y (t) of mechanical load (m) do with respect to the input current i (t) of the electrohydraulic control transfer function representation between (A)

$\frac{Y\left(s\right)}{I\left(s\right)}=\frac{1}{{\mathrm{<figure-callout\; id="2"\; label="m\; d\; s"\; filenames="HDA0000048335270000012.png"\; state="\{\{state\}\}">m</figure-callout>}}_d{s}^{}{}^2+B_{d}s}---\left(1\right)$

M in the formula _d---be called equivalent mass;

B _d---be called equivalent viscosity viscous damping coefficient.

Formula (1) is exactly the mathematical model of practical actuator on the engineering in the electric liquidus displacement servo-system, and it is a second-order system.Known the form that actuator's mathematical model adopts transfer function to express, only accomplished qualitative understanding it.Have only m in the formula (1) _dAnd B _dThe size identification of these two parameters is come out, and could accomplish the quantitative identification to actuator's mathematical model.So, how it is quantitatively discerned? In order to address this problem, the present invention realizes that the technological scheme that purpose is taked is:

Actuator's parameter recognition device in a kind of electric liquidus displacement servo-system; Be made up of step current signal generator, electrohydraulic control, oil hydraulic cylinder, mechanical load, linear displacement detecting sensor, recording apparatus and hydraulic power, wherein step current signal generator, electrohydraulic control, oil hydraulic cylinder, mechanical load, linear displacement detecting sensor and recording apparatus are docile and obedient the preface connection; Described step current signal generator also directly links to each other with recording apparatus; Described hydraulic power is connected with oil hydraulic cylinder with electrohydraulic control respectively.

Described electrohydraulic control, oil hydraulic cylinder and mechanical load formed to carry out the actuator of parameter recognition.

Said step current signal generator produces the step current signal and offers the electrohydraulic control in the actuator; Electrohydraulic control converts current signal to the displacement of spool; And then convert the load flow in the hydraulic system again to; And be enlarged into that large-power hydraulic can promote the piston of oil hydraulic cylinder and the mechanical load of being with is done linear motion, the linear displacement detecting sensor with piston and come out and deliver to recording apparatus and carry out record with the linear displacement input of mechanical load; Meanwhile, the step current signal of step current signal generator output is also delivered to recording apparatus it is noted.

To achieve these goals, another technological scheme that the present invention taked is: actuator's parameter identification method in a kind of electric liquidus displacement servo-system.

With amplitude is I _MStep current signal i (t) be input to the electrohydraulic control in the actuator, obtain the output response of actuator, just obtain the linear displacement y (t) that hydraulic cylinder piston and institute move with mechanical load.Write out corresponding differential equation according to transfer function formula (1)

$m_d\frac{{\mathrm{dy}}^2\left(t\right)}{{\mathrm{<figure-callout\; id="2"\; label="dt"\; filenames="HDA0000048335270000012.png"\; state="\{\{state\}\}">dt</figure-callout>}}^2}+B_d\frac{\mathrm{dy}\left(t\right)}{\mathrm{dt}}=I_M---\left(2\right)$

Under zero initial condition, the time solution of obtaining this differential equation does

$y\left(t\right)=\frac{I_M}{B_d}[t-\frac{m_d}{B_d}(1-e^{-\frac{B_d}{m_d}t})]---\left(3\right)$

Make

then formula (3) can be write as

$y\left(t\right)=\frac{I_M}{B_d}[t-T(1-e^{-\frac{1}{T}t})]---\left(4\right)$

According to this time solution of formula (4), can find following significant inference:

(1) when t → ∞, can be write as

$y\left(t\right)=\frac{I_M}{B_d}(t-T)---\left(5\right)$

(2) time solution is a straight line when t → ∞, and its slope is on abscissa intercept is

According to the above-mentioned theory analysis and through practice test, actuator's parameter identification method in the electric liquidus displacement servo-system provided by the invention may further comprise the steps:

(1) be that the step current signal of certain certain value (the amplitude size is decided according to the specification of electrohydraulic control) is input to electrohydraulic control with amplitude; Drive oil hydraulic cylinder and institute's mechanical load of be with moves through hydraulic power, by the linear displacement signal of its motion of linear displacement detecting sensor detection;

(2) with recording apparatus with described step current signal and linear displacement signal in time change procedure note, get into the straight line ascent stage until the linear displacement signal;

(3) the straight line ascent stage of displacement signal along the line is made straight line, and prolongation is crossing with time shaft.

(4) measure the slope of said straight line and the values of intercept that intersects with time shaft.

(5), obtain the equivalent viscous damping coefficient of actuator in the electric liquidus displacement servo-system with the slope of said step current signal amplitude divided by said straight line;

(6) values of intercept on said equivalent viscous damping coefficient and the said time shaft is multiplied each other, obtain the equivalent mass of actuator in the electric liquidus displacement servo-system.

The advantage and the beneficial effect of actuator's parameter recognition device and identifying method mainly are in the electric liquidus displacement servo-system of the present invention: obtain after the equivalent viscous damping coefficient and equivalent mass of actuator; The Control Parameter size of electronic controller just can design and adjust according to these two parameters of actuator in the electricity liquidus displacement servo-system; Thereby overcome the blindness of the Control Parameter adjustment of electronic controller; The adjustment of electric liquidus displacement servo-system is sparing of one's energy and the time, but also can obtains good static properties and dynamic performance.

Four. description of drawings

Fig. 1 is actuator's parameter recognition device skeleton diagram in the electric liquidus displacement servo-system of the embodiment of the invention.

When Fig. 2 is the actuator parameter recognition of the embodiment of the invention for the linear displacement signal graph of step signal input.

Five. embodiment:

In order to deepen that understanding of the present invention further is described in detail specific embodiment of the present invention below in conjunction with accompanying drawing, this embodiment only is used to explain the present invention, does not constitute the qualification to protection domain of the present invention.

Fig. 1 is actuator's parameter recognition device skeleton diagram in the electric liquidus rate servo system of the embodiment of the invention.The involved recognition device of its expression embodiment of the invention; It comprises a step current signal generator 110, electrohydraulic control 121, oil hydraulic cylinder 122, with mechanical load 123, linear displacement detecting sensor 130, a recording apparatus 140 and a hydraulic power 150; Said step current signal generator 110, electrohydraulic control 121, oil hydraulic cylinder 122, mechanical load 123, linear displacement detecting sensor 130 and recording apparatus 140 are linked in sequence; Meanwhile, step current signal generator 110 also is directly connected to recording apparatus 140; Hydraulic power 150 is connected respectively to electrohydraulic control 121 and oil hydraulic cylinder 122.Wherein electrohydraulic control 121, oil hydraulic cylinder 122 and mechanical load 123 are formed actuator 120.

It is I that said step current signal generator 110 provides current amplitude _MStep signal; Be sent to electrohydraulic control 121; Electrohydraulic control 121 converts current signal to the displacement of spool; And then through the high power hydraulic of hydraulic power 150 after amplifying can drive oil hydraulic cylinder 122 piston and the mechanical load of being with 123 carry out straight line motion; Measure hydraulic cylinder pistons and the institute size with the mechanical load linear displacement by linear displacement detecting sensor 130, the signal of step current signal generator 110 and linear displacement detecting sensor 130 is all delivered to recording apparatus 140, the hydraulic cylinder piston that recording apparatus 140 is noted and the mechanical load linear displacement signal of being with as shown in Figure 2.

Actuator's parameter identification method may further comprise the steps in the said electric liquidus displacement servo-system:

(1) be I with amplitude _MThe step current signal i (t) of (the amplitude size is decided according to the specification of electrohydraulic control) is input to electrohydraulic control, drives oil hydraulic cylinder and institute's mechanical load of be with moves through hydraulic power, by the linear displacement signal y (t) of its motion of linear displacement detecting sensor detection;

(2) with recording apparatus with the linear displacement signal y (t) of the step current signal i (t) of input and output in time change procedure note, said linear displacement signal comprises the curved portion 1 and the follow-up straight line rising part 2 of The initial segment;

(3) make straight line along the straight line rising part 2 of said linear displacement signal, and prolongation intersect at the P point with time shaft;

(4) measure the slope K of said straight line and the values of intercept T of ordering with the P that time shaft intersects;

(5) with said step current signal amplitude I _MDivided by the slope K of said straight line, obtain the equivalent viscous damping coefficient B of actuator in the electric liquidus displacement servo-system _d

(6) with said equivalent viscous damping coefficient B _dMultiply each other with the values of intercept T on the said time shaft, obtain the equivalent mass m of actuator in the electric liquidus displacement servo-system system _d

Qualitative understanding by actuator's mathematical model can know that the mathematical model of actuator is a second-order system.According to the structural type of mathematical model, can confirm the structural type of electronic controller in the electric liquidus displacement servo-system.

Obtain above-mentioned actuator the equivalent viscous damping coefficient B _dWith equivalent mass m _dAfterwards, the parameter in actuator's mathematical model is just quantitatively identified, according to the equivalent viscous damping coefficient B of actuator _dWith equivalent mass m _dThe size of these two parameters just can design and adjust the Control Parameter of electronic controller in the electric liquidus displacement servo-system.

Facts have proved that the method for the invention not only can be sparing of one's energy and the time, and can obtain good static properties and dynamic performance in electric liquidus displacement Servo System Design and debugging.

Claims (2)

1. actuator's parameter recognition device in the electric liquidus displacement servo-system; It is characterized in that: be made up of step current signal generator, electrohydraulic control, oil hydraulic cylinder, mechanical load, linear displacement detecting sensor, recording apparatus and hydraulic power, wherein step current signal generator, electrohydraulic control, oil hydraulic cylinder, mechanical load, linear displacement detecting sensor and recording apparatus are docile and obedient preface and are connected; Said step current signal generator also directly links to each other with recording apparatus; Said hydraulic power is connected with oil hydraulic cylinder with electrohydraulic control respectively.

2. the identifying method of actuator's parameter recognition device in the electric liquidus displacement servo-system as claimed in claim 1, it is characterized in that: concrete steps are following:

(1) amplitude is input to electrohydraulic control for the step current signal of certain certain value, drives oil hydraulic cylinder and institute's mechanical load of be with moves through hydraulic power, by the linear displacement signal of its motion of linear displacement detecting sensor detection;

(2) adopt recording apparatus with described step current signal and linear displacement signal in time change procedure note, until linear displacement signal entering straight line ascent stage;

(3) the straight line ascent stage of displacement signal along the line is made straight line, and prolongation is crossing with time shaft;

(4) measure the slope of said straight line and the values of intercept that intersects with time shaft;

(5), obtain the equivalent viscous damping coefficient of actuator in the electric liquidus displacement servo-system with the slope of said step current signal amplitude divided by said straight line;

(6) values of intercept on said equivalent viscous damping coefficient and the said time shaft is multiplied each other, obtain the equivalent mass of actuator in the electric liquidus displacement servo-system.

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