SU1740806A1 - Electrohydraulic servo robot drive - Google Patents

Abstract

Use: in control systems of industrial robots and manipulators. The invention: the corrective device ensures the invariance of the drive quality indicators to the variable parameters of the load. The adjustment of parameters is carried out on the basis of information about the torque effects on the drive. This information is removed from the outputs of the second and sixth adders and with the help of the division unit, as well as the first, second, fourth, and fifth multiplication units, is inserted into the correction device and ensures the corresponding correction of the input signal. 2 Il.

Description

The invention relates to hydraulics and can be used in control systems for industrial robots and manipulators.

The purpose of the invention is to increase accuracy and stability.

Fig. 1 shows a block diagram of an electro-hydraulic servo drive: Fig. 2 is a kinematic diagram of a robot.

The electro-hydraulic follow-up drive of the robot contains a serially connected error meter 1, the first differentiating element 2 with deceleration, the 3 division unit, the second differentiating element 4 with deceleration, the first multiplication unit 5, the first adder 6, the second multiplication unit 7, the first amplifier 8, the actuator 9 of the regulator of the pump 10 connected by hydrolines 11 and 12 with a hydraulic motor 13 with a reducer, the output shaft 14 of which is kinematically connected with the working member of the robot and the first position sensor 15 connected by its output to toromu input meter

. 1 mismatch, the output of which through the aperiodic link 16 of the second order is connected to the second input of the first adder 6, the first quad 17 in series, the third multiplier 18, the second adder 19, the second input of which is connected to the output of the first voltage source 20, and the output - to the second inputs of the first 5 and fourth 21 multipliers, the first input of the last is connected to the first input of the fifth multiplication unit 22 and the output of the 3 division unit, and the output via the first aperiodic link 23 of the first order - to the third input the first adder 6, the fourth input of which through the second aperiodic link 24 of the first order is connected to the output of the fifth multiplication unit 22, sequentially connected the third adder 25, the first and second inputs of which are respectively connected to the second input of the fifth multiplication unit 22 and the second source 26 a reference voltage, and a second amplifier 27, the output of which is connected to the second input

"In"

CD

the second multiplication unit 7, and the second input of the 3 division unit to the output of the third adder 25, connected in series to the second position sensor 28, the fourth adder 29, the second input of which is connected to the output of the third source 30 of the reference voltage, the fifth adder31 and the sixth block 32 multiplies, as well as force sensor 33, fourth reference voltage source 34 and first speed sensor 35. In addition, it additionally contains serially connected third position sensor 36, first functional sinus transducer 37 and second quad 38 whose output is connected to the third input of second adder 19, third amplifier 39 connected in series, second functional sinus transducer 40, seventh block 41 multiplying, the second input of which is connected to the output of the second speed sensor 42, the eighth block 43 multiplying and the sixth adder 44, the output of which is connected to the first input of the third adder 25, and its second th input through the ninth multiplication unit 45 to the output (. - / first speed sensor 35, serially connected fifth voltage source 46 and seventh adder 47, the output of which is connected to the second input of the eighth multiplication unit 43, serially connected sixth source 48 the reference voltage and the eighth adder 49, the first input of which through the third quad 50 is connected to the output of the fourth adder 29, its second input through the tenth multiplication unit 51 to the output of the sixth multiplication unit 32, and the output to the second inputs of the third block 18 intelligently neither the seventh adder 47, as well as the serially connected ninth adder 52, the first and second inputs of which are respectively connected to the outputs of the sixth multiplication unit 32 and the fourth adder 29, and the eleventh multiplication unit53, the second input of which is connected to the output of the first quad 17, and the output - to the second input of the ninth multiplication unit 45, the input of the first quad 17 through the third functional cosine converter 54 being connected to the output of the second sensor. 36 position and the input of the third amplifier 39, the output of the sensor 33 of the force to the second input of the sixth multiplication unit 32, the second input of the fifth adder 31 to the output of the fourth source 34 of the reference voltage, and the second input of the tenth multiplication unit 51 to the output of the fifth adder 31.

Electro-hydraulic follower drive works as follows.

A control input q 1 is supplied to the input of the follower drive, providing the required control law.

At the output of the comparison element 1, an error signal d is generated, which, after correction in blocks 2-7 and 16, amplifies, arrives at the actuator 9 to the regulator of the pump 10, which, creating a flow of working fluid in the hydraulic lines 11 and 12,

0 affects the motor and gearbox 13, the output shaft of which changes the position of the control object, reducing the mismatch d. Electro-hydraulic drive when working with various loads

5 and also due to the mutual degrees of mobility of the executive organ, it has variable moment characteristics, which can vary within wide limits. This reduces the qualitative performance indicators of the hydraulic drive and leads to the loss of stability of its operation. As a result, the problem arises related to ensuring the invariance of the dynamic properties of the drive to changes in its moment load characteristics, which allows to ensure the stability of the specified quality of the system.

This description describes the electro-hydraulic servo drive

0 turns work relative to the vertical axis of its executive organ. The kinematic scheme of the robot is shown in FIG.

In Figures 1 and 2, the following symbols are introduced: qi, q2, q3 — the corresponding generalized coordinates of the degrees of mobility of the robot; qi, q2, q3 are the rates of change of the generalized coordinates qi, Q2, and qs; U - amplified signal; GHz, T2, TZ - respectively

0 mass units executive ortan; mr is the mass of the captured cargo; 12, distance from the center of mass of the second and third links to their axes of rotation; h - distance from the center of mass of the third link to the center

5 gripper.

In order to achieve quality control of the coordinate qi. it is necessary to compensate for the negative effects of changes in the coordinates q2 and q2, as well as qs and

0 on drive dynamic properties

The kinematic energy of all the moving masses of the actuator (FIG. 2) is represented by

T + rri2l22 + N3 + tz (1z + qs) +

5 + tg (s + q3) q 2+

- q23 + 1/2 {Isi + (S2 - IS3) sin2qz +

A

 + 1mz -t m2l22 + t20z + qs} 2 + + mr (Is + qs + Is) cos2q2} qt2.

4a potential energy is

П + тз (1з + дз) + тг (1з + дз + 1з) stn q2,

where g is the acceleration of free fall;

Isi, Is2. Is3 are the moments of inertia of the corresponding links relative to their longitudinal axes;

INI, Iw2, and yy moments of inertia of the corresponding links relative to the transverse axes passing through their centers of mass.

The following relations are fulfilled simultaneously: fc- - {IS1 + OS2 + lS3) sin Q2 +

H

+ IN2 + iN3 + GP2 I 2 + tz03 + Q3) +

+ gpg {1z + qs + h) cos2 q2} qi,

sCLzILo

ffqi () - (si + (+ IS3) sin2q2 +

 + lN3 + m2l22 + tz (1z + qs} 2 + + mr (qs + 1z) cos2q2}, qi + {2 tz (s + qa) + + mr (lj + qs + 1z) cos (q2) + t s2 + s3 - IN2 -lN3 - Sh2G2 - rm (3 + RZG.

- mr (5-i-q3 (+ Is) sin (2q2) q2} qi - H (q2, q3) qi + h (q2, q2, q3.q3) qi, where H, h are variable functions. Considering Lagrange equations of the 2nd kind of moment effect on the drive of the robot's rotation (coordinate qi) has the form

MV H (q2q3) q l + h (q2.q2, q3, q3) qi (1) The transfer function of an open drive can be represented as

  W (P) Wy {P) Wp (P) WHrM (P) Wx (P),

where P is the differentiation symbol,

W (P) open drive transfer function;

Wy (P) and Wp (P), respectively, the transfer functions of the amplifier 8 and the regulator 9 of the pump 10;

Mngm (P) is the transfer function of a hydraulic transmission consisting of a pump 10 i of a hydraulic motor 13;

A / C (P) is the transfer function of the correction device.

Moreover, the transfer function of the hydraulic transmission is

(HO. YlV

lVE (L, h QOIW | L

K, (l ,, ht6oiW | ij

where y is the angle of rotation of the regulator 55 of the pump 10,

K-ilLsl DE s const, ym const,

five

ten

15

0

five

0

five

0

0

five

Ut - the maximum angle of rotation of the regulator of the pump 10;

KE - the reduced value of the coefficient of bulk elasticity of the liquid;

ip - gear ratio;

Wg is the characteristic volume of the hydraulic motor 13;

Wit is the characteristic volume of the pump 10;

It is the speed of rotation of the pump 10;

V is the volume of the working fluid in the discharge hydraulic line 11 and the discharge cavity of the pump 10,

1E is the working fluid fluid.

Expression (2) shows that the parameters of the transfer function WHDM (P) are essentially variable and depend on AND (q2, qa), h (q2, Q2. Qs, qs). As a result, the dynamic properties of the electro-hydraulic servo drive significantly change. In order to preserve the dynamic properties of the robot's electro-hydraulic servo drive in question, it is necessary to stabilize all the parameters of the transfer function W (P).

The WK (P) correction is performed using a second-order aperiodic link of order 16 with a transfer function.

one

(TiP-b1) () two differentiating units with a slowdown of 2 and 4 types

W2 (p) xiTnVTi} - W4 (p)

as well as periodic links 23 and 24 with transfer functions

No. w24 (P)

Wie (P) W23 (P)

T2P + 1

The parameters Ti and T2 are chosen sufficiently small in order to give the drive the necessary dynamic properties. The second-order aperiodic link 16, the differentiating links with deceleration 2 and 4, 3 and the first-order aperiodic links 26 and 31 are included as shown in FIG.

The sensors 36 and 28 are installed in the second and third degrees of the mobility of the robot, respectively (see Fig. 2).

Functional converters 37 and AO implement the sin function. and the function transducer 54 is a cos function.

As a result, at the output of the quadrants 38 and 17, respectively, the signals are formed

Sln2Q2 and.

The speed sensors 42 and 35, respectively, are installed in the second and third degrees of the mobility of the robot (see Fig. 2} and the values of and q3 are measured.

The amplifier 39 has a gain factor of 2, therefore, at the output

The multiplication unit 41 generates a signal qa sln2q2.

Sources 30 and 34 of the reference voltage respectively form signals 1h and 1h. The first and second positive inputs of adders 29 and 31 have unit gains, therefore, the signals z + dz and 1z + dz + 1z, respectively, are formed at their outputs, and at the outputs of the quad 50 and block 51 multiply, respectively (z + dz) 2, rtir $ + Chz + 3), since sensor 33 measures the mass of the seized load. The source 48 of the reference voltage supplies to the third unitary positive input of the adder 49 a signal equal to m + L3 + mate. The second (from the side of block 51 multiplies the first positive inputs of adder 49, respectively, have a unit gain and a gain equal to gpz. As a result, the output of multiplication unit 18 produces a signal cos Q2 mz + mate + gpz (g + dz) + + mr (i $ + qa + bf,

The source 20 of the reference voltage is applied to the second positive input of the adder 19 i by a unit gain signal Isi h lip. The third (from the side of the quad 38) and the First positive inputs of this adder, respectively, have a gain factor equal to S2 + Is3 and a unit gain factor. As a result, at the output of the adder 19, a signal si Ј f2 N (IS2 bs) smzq + 1m2 b 1c + tinrte + gpz Oz + dz), + mr (c + qs + 1z) is formed

c, az H (qa, dz)

At the output of the source 46 of the reference voltage, the signal Is24 Isa is formed. The second is negative (from the adder 49) and the first positive inputs of the adder 47 have unit gains. As a result, the output of the multiplier 43 produces a signal

And Isa + is3 - Iwa - mz - mala - tz (1z-dz} 2- -tg {1 -dz-Nz) 1 sin (2qa) q2.

The first (on the side of the multiplier 32) and the second positive inputs of the adder 52, respectively, have a gain of 2 and a gain of 2 tons. As a result, at the output of multiplication unit 45, a signal is generated that is equal to B (z + dz) t t t (z + dz + 1z) cos2 (yes) dz.

The positive inputs of the adder 44 have unit gains. As a result, a signal is generated at its output.

gfqa yes, dz, dz) A + B.

The first input of the adder 25 (on the side of the adder 44) has a gain factor equal to C, and its second input has a gain factor equal to one. A source

the reference voltage 26 has an output signal proportional to 0.01 Wg2 Lp2. As a result, a signal Uh + 0.01 W2gi2p is generated at the output of the adder 25, which

is supplied to division unit 3. Amplifier 27 has a gain factor proportional to the value (0.01 Wg ip) -1. Thus, taking into account the type of transfer functions W2 (P). W4 (P). Wi6 (P), W2C (P). W24 (P) output

block 7 multiply form-1 signal

(

Ke (L, h OOlW $)

R

, rtsYn 1. E (bE | -001 w | ip P t

00 (Ljh 00 Wn 1rP1G, ri) tgr + (}

As a result, the transmittance function of the corrective condition has

(j l2if-15 g. 5, JJLL. uki.1

U (L, hvOO V | E1 ООШ | ф)

L CH (-

TIOQI.jhfWaip l.

1-fr --- J,

five

0

five

five

0

five

0

and the transfer function of the direct drive circuit will be

W (P) Wy (P) WP (P)

From this expression it can be seen that all the parameters of the transfer function W (P) in the course of overation of the developed correction remain constant, and therefore the dynamic properties and quality indicators of the entire drivetrain, i.e. accuracy and stability will not depend on the variables H and h.

idKHM way, in the drive provided the desired invariance to change the load characteristics.

The practical implementation of the proposed device is not difficult, since it uses only typical electronic elements.

Claims (1)

Invention Formula Electro-hydraulic follower of the robot, containing a serially connected error meter, the first differentiating element with deceleration, the division unit, the second differentiating element with deceleration, the first multiplication unit, the first adder, the second multiplication unit, the first amplifier, the drive of the regulator of the pump connected rollers with a hydraulic motor, the output shaft of which is kinematically connected with the working device of the robot and the first position sensor connected to the error meter, the output cat through the aperiodic link, the second order is connected to the input of the first adder, and the first quadrant connected in series, the third multiplication unit, the second adder, whose input is connected to the first reference voltage source, and the output to the inputs of the first and fourth multiplication blocks, another input the latter is connected to the input of the fifth multiplication unit and the output of the division unit, and the output through the first aperiodic link of the first order is connected to the input of the first accumulator, whose input through the second aperiodic link of the first order Connected with the tricks of the fifth multiplier unit, the third adder connected in series, the inputs of which are connected to the input of the fifth multiplication unit and the second source of the reference voltage, and the second amplifier, the output of which is connected to the input of the second multiplication unit, and the second input of the division unit - to the output a third adder, a series of connected second position sensors and a fourth adder, the input of which is connected to the third reference voltage source, as well as the fifth adder, the sixth multiplication unit, the force sensor, the fourth source The nickname of the reference voltage and the first speed sensor are distinguished by the fact that, in order to increase accuracy and stability, it is equipped with a second and third position sensors, a second speed sensor, first and second functional sinus transducers, a functional cosine transducer, the second and third quadrants, the third amplifier, the seventh, eighth and ninth, tenth and eleventh multiplication blocks, the sixth to seventh adders, as well as the fifth and sixth sources of reference voltage, while sequentially connected s the third position sensor, the first sinus transducer and the second quad, the output of which is connected to the input of the second adder, are connected in series to the third the amplifier, the second sinus converter, the seventh multiplication unit, one input of which is connected to the second speed sensor, the eighth multiplication and the sixth summatgr, the VUHOD of which is connected to the third adder's input, and the other input of the sixth adder through the ninth multiplication unit is connected to the first sensor. first, the fifth source of the reference voltage and the seventh adder, the output of which is connected to the input of the eighth multiplicator, are connected in series, the sixth source of the reference voltage and the eighth summation are connected in series , One- third input of which through squarer -Connect, oyhodu fourth adder and its other input through a tenth multiplier - to the output of the sixth block of multiplication, and you / od - to the inputs of the third multiplier and the seventh adder, are connected in series the ninth adder, the inputs of which are connected to the outputs of the sixth block of multiplication and the fourth sum of the ora, and the eleventh WLM of multiplication, one input of which is connected to the output of the first quadrator, and the output to the input the ninth multiplication unit, the input of the first quadrant through the cosine converter is connected to the third position sensor to the input of the third amplifier, the force sensor connected to the input of the sixth block multiplying, the inputs of the nth adder are connected to the fourth adder and the fourth source of the reference voltage. and the output is to the inputs of the sixth and tenth blocks of multiplication, W 9080W.I / 77 / FIG. 2