SU1294570A1 - Apparatus for timed motion of working member of machine tool - Google Patents

Abstract

The invention relates to the engineering industry, in particular to a precision machine-tool industry. The purpose of the invention is to increase the dynamic accuracy of the device for mixing the working body of the machine by ensuring the constant dynamic characteristics of both control channels by automatically correcting the constant values of these channels. To do this, the device, containing, its two-channel system for controlling the movement of the machine tool and the synchronization unit of two control channels, introduced phase-ahead links with adjustable time constants. 2 Il. SS N3 SO e

Description

The invention relates to the machine-building industry and can be used in machine-tool construction, especially in precision, for example, in coordinate-boring, coordinate-grinding machines, in a portal machine) K) i-i:

Each 1-:) retention is to increase the dynamic N: rp pin of the device for the stirring motor 12 and the lead screw 8, designed to move the right end of the cross member 5. To match the movements of the ends of cross member 5 relative to the uprights 3 and 4 when processing the workpieces by lifting or the crossbar 5 is lowered, an electrical connection is provided between the movement control channels of the spindle screws 7 and 8. This connection is carried out through the comparison unit 28, to the inputs

i; 1 of the machine body by which the sensors 13 and 14 are displaced by the ends of the cross member 5, and the output is connected to the inverting input of the comparison unit 18 and the non-inverting input of the comparison unit 23. To control the position of the spindle head 6 is embedded in it.

Pecheni constant dynamic characteristics of both control channels due to automatic correction of the values of the constant time of these channels.

FIG. 1 shows a machine with arrangements for the ends of the cross member 5, and the output is connected to the inverting input of the comparison unit 18 and the non-inverting input of the comparison unit 23. To control the position of the spindle head 6 is embedded in it.

The tool for moving the working body 15 is a sensor 29 for linear movements, for example, a machine, a general view; in fig. 2 - prin-inductive potentiometric conversion circuit of the phase-advancing link analogue-type recipient, and the corresponding scale of 30 reference is set on the cross-piece 5 parallel to the direction of the two times the adjustable time constant.

The machine (Fig. 1) contains frame 1, table 2, pillars 3 and 4, crossmember 5 and spindle head 6. Two spindle screws 7 and 8, which interact with nuts 9 and 10, are designed to move cross member 5 along guide racks 3 and 4, and connected to the shafts of electric motors 20

headstock spouse 6.

The linear displacement sensor 29 is connected to functional converters 31 and 32, for example, a diode one, and they, in turn, are connected to boosting links 21 and 26. Each of the two DC-phase inverters 11 and 12. Two transducer units 21 and 26 with adjustable time sensors 13 and 14 linear time intervals (Fig. 2) represent

is a boost link, which includes an operational amplifier 33, a constant capacitor 34 and the same transistors 35 and 36, using 30

Spaces, such as inductosynum impulse sensors, are built into the left and right ends of the crossmember 5, and the reference scales 15 and 16 corresponding to these sensors 13 and 14 are mounted on racks 3 and 4 parallel to the axis of the spindle screws 7 and 8. Controlling the movement of the cross member 5 relative to the uprights 3 and 4 leads through two channels. In this case, one of the control channels (conditionally, the first) contains a block 17

as adjustable resistances. The transfer coefficient of such a link is the ratio of the magnitude of the active resistance of the collector junction of the transistor 36 to the value of the active resistance of the collector junction

the input of a task, for example, a digital program transistor 35, and an adjustable constant mosaic device of unified time is determined by the product of a large discrete type control system (UBSSR-D), sensor 13 moves the left end of the crossbar 5 relative to the scale 15 of reference, block 18 Comparison - Q

for example, on elements of the same series. The device works as follows.

digital-to-analog converter 19, on-pre, when setting up the machine, with an example of a code converter taking into account the position of the zero points of the indication to the corresponding voltage, the usi counting on the scales 15 and 16, thus,

20, Phase-wise link 21 with a regulation-so that they lie in the plane of the table 2.

the time constant, for example, the forma- tion of the 45, ensuring the equality of the coordinating element controlled by the power potential of the capacitor capacitance 34 by the amount of adjustable active resistance of the collector junction of the transistor 35.

a former 22, for example a thyristor, an electric motor 1 and a lead screw 7, designed to move the left end of the cross member 5.

The other control channel (conditionally, the second one) contains a task input block 17, a displacement sensor 14 for the right end of the cross member 5 relative to the reference scale 16, a comparison block 23, a digital-to-analog converter 24, an amplifier 25, an adjustable constant-time 26, a thyristor converter 27, elekt50

55

The position of the left and right ends of the cross member 5 relative to the respective scales 15 and 16 simultaneously means ensuring parallelism of the cross member 5 and the table mirror 2. The zero point on the scale 30 is assumed to correspond to the left extreme position of the spindle head 6 on the crossbar 5. Under these conditions, the dependencies The reduced electromechanical time constants of the engines 1 and 12 from the position of the spindle head 6 on the cross member 5, which are installed analytically, can be described as follows.

a rotor motor 12 and a spindle screw 8 for moving the right end of the cross member 5. In order to match the movements of the ends of the cross member 5 relative to the uprights 3 and 4 when machining the workpieces by raising or lowering the cross member 5, electrical communication is provided between the control channels of the movement of the running screws 7 and 8. This communication takes place through comparison unit 28, to the inputs

 The sensors 13 and 14 are connected to the ends of the cross member 5, and the output is connected to the inverting input of the comparison unit 18 and the non-inverting input of the comparison unit 23. To control the position of the spindle head 6 is embedded in it.

A linear displacement sensor 29, for example, an inductive potentiometric converter of analog type, and the corresponding reference scale 30 is mounted on the crossbar 5 parallel to the direction of the motor

headstock spouse 6.

The sensor 29 is linearly spaced to the functional transducers 32, for example, a diode one, and it is associated with forcing 21 and 26. Each of the two links 21 and 26 is constant time (Fig. 2)

 transistor 35, and the adjustable time constant is determined by the product of

Capacitor capacitance 34 by the amount of adjustable active resistance of the collector junction of the transistor 35.

At the same time, ensuring equality of coordination

The position of the left and right ends of the cross member 5 relative to the respective scales 15 and 16 simultaneously means ensuring parallelism of the cross member 5 and the table mirror 2. The zero point on the scale 30 is assumed to correspond to the left extreme position of the spindle head 6 on the crossbar 5. Under these conditions, the dependencies The reduced electromechanical time constants of the engines 1 and 12 from the position of the spindle head 6 on the cross member 5, which are installed analytically, can be described as follows.

For

 T

e Ti -

engine 11

Jgi + (Ch- tshb-) 1H 1 (1) Ce.

is an electromechanical constant of engine time 11; t „is the mass of the crosspiece 5; Spindle weight of spindle head 6; t is the distance between the axles

screws 7 and 8;

C2 is the capacitance of the capacitor 34, which is part of the boost link 26; X is the coordinate of the position of the spindle head 6 relative to the scale of 30 reference;

hi is the lead screw pitch 7; K 1 is the active resistance of the engine circuit 11;

l, see | - engine constructive engine 11;

- engine drive stream 11. engine 12

F: For

Tg

 + (f +) K 2 (2) - forcing link 26

C; 2Sm2F 2

T C2Ro2e

.

where T2 is the electromechanical constant of engine time 12; h2 - spindle pitch 8; H 2 active resistance of the root

engine circuit 12;

C; 2, Cm2 - engine design constants 12;

02 is the excitation flow of the engine 12. For the same dependencies, the time constants of the forcing links 21 and 26 should vary as a function of the position of the spindle head 6. This is achieved as follows. Considering that

T, R, C ,,

T is the time constant of the forcing link 21;

RI is the active resistance of the collector junction of the transistor 35, which is part of the forcing element 21;

Ci is the capacitance of the capacitor 34, which is part of the boost link 21,

T2 R2C2, (4)

e TZ is the time constant of the forcing link 26;

R2 is the resistance of the collector junction of the transistor 35, which is part of the forcing element 26,

mean, in turn,

RI Roie

DGSh

where ROI and t) 1 are constant parameters depending on the type of transistor 35,

included in the force link 21; -control voltage at the base of the transistor 35, which is part of the boost circuit 21,

R, R ,,

(6)

where Ro2 and 1) 2 are constant parameters, depending on 10c on the type of transistor 35,

included in the force link 26;

U2 is the control voltage at the base of the transistor 35, which is part of the forcing star, 15 to 26.

We obtain the equations relating the control voltage with the value of the time constant:

for boost link 21

T |

CiRoie

L

(7)

 boost link 26

T C2Ro2e

.

(eight)

25

40

Equating the right-hand sides of equations (1) and (7) and equations (2) and (8), respectively, let us establish the relationship between the coordinate position of the spindle head 6 and the magnitude of the control voltage at the base of the transistor 30 tor 35:

for the first control scale + (+ shshb) -% R |

 C ,, (9)

35

for the second control channel

Jg2 + (+ mu, 6) R 2 Sysm2F 2

 C2Ro2e. (10)

The logarithm of equation (9) and (10), we define the analytical expressions for the static characteristics of the functional converters 31 and 32;

for functional converter 31

 and, - i 1 si + (.., .l - C.RoiCia.cbT 01)

for functional converter 32

50 ,, i (+ tsh.4 -) - RH2. Dch C2Ro2C2CM2 (DY

Thus, since the change in the constant time of the forcing element 21 occurs due to the change in the active resistance of the collector junction of the transistor 35, and the value of the specified resistance, in turn, depends on the value of the control signal fed to the cross member 5 until until the signal at the output of comparison unit 23 becomes zero.

To set the same program of movement of both ends of the cross member 5, a control signal is supplied to both control channels from the same task input block 17. However, in the process of processing the workpieces by raising or lowering the cross member 5 along the uprights 3 and 4 of the transistor 35 from the output of the functional converter 31, the required law of changing the time constant is formed using the functional converter 31, the static characteristic (11) of which establishes a relationship between the position of the spindle head 6 and the magnitude of the control signal based on the transistor 35, and, consequently, the constant value of the time of the forcing element 21. Similarly

thus, the static characteristic (12) for the differences in the electromechanical-functional converter shown is 32 of the permissible time constants of the motors 11 and

It is necessary to implement the required law of change 12, caused by the movement of the spindle

the constant time of the forcing element 26 of the headstock 6, possible violation of synchronicity as a function of the position of the spindle head 6 of the displacements of the ends of the cross member 5 (when starting the value of the transmission coefficient of the force forcing, reverse, transition from one speed to

link 21 remains constant at the expense of another). Therefore, in order to avoid disturbing the fact that the control signal from the output of the functional converter 31 is fed simultaneously to the bases of both transistors 35 and 36, and with the same change in the active resistances of the collector junction transistors 35 and 36, the ratio of these resistances does not change. For the same reason, the transmission coefficient of the forcing link 26 remains unchanged.

After preliminary adjustment of the device it is prepared for work. Further, 25 of rank 5 must accelerate (or stop as the cross member 5 moves out of one massage) more slowly than the right end,

positions to another, as well as during processing. However, at the same time as moving the blanks by raising or lowering the crossbar 5 along the uprights 3 and 4, the program for the required movement of the crossbar 5 sets the synchronism of movement of the ends of the crossbar 5 into the control system the boosting elements 21 and 26 are inserted.

Suppose, for definiteness, that 2Q spindle head 6 has moved along cross-piece 5 to the left of its middle position. Then, the reduced electromechanical time constant for the engine 11 increases, and for the engine 12 it decreases, and in dynamics the left end of the tailstock 6 changes us, the signal from the sensor 29 of its movements enters the inputs of the functional converters 31 and

with the help of input block 17, 0–2, which leads to a change in the signals by

neither, but the actual position of the crossbar 5 is determined by the indications of the sensors 13 and 14 of the movements of the ends of the perepin 5. If there is a discrepancy between the desired and actual positions of the outputs. At the same time, the signal at the output of converter 31, arriving at the base of transistor 35, decreases, and the active resistance value 1 of the collector junction of transistor 35 increases, causing the left end of crossbar 5 at the output — the increase in the time constant of the comparison fory block 18 appears differential circuit 21. At the same time, the analog signal, which is converted using digital-analog converter 19 from

digital form to voltage. Last thing

40

This leads to a decrease in the time constant of the forcing element 26. Due to the corresponding formation of the static characteristics (1) and (12) of the functional transducers 21 and 26, the reduced electromechanical time constants of the motors 11 and 12 constant time of the corresponding forcing links 21 and 26 are achieved at

amplified in the amplifier 20, passes through the forcing link 21, the thyristor converter 22 and is fed to the electric motor 11, and it reports the rotation of the driving screw 7, which, turning, raises or lowers the left end of the cross-member 5 until the signal is at 45 any position the spindle head 6 at the output of the comparison unit 18 will not become equal to the cross-bar 5. Thus, the change of the legal zero is zero. At the same time, if there is a discrepancy between the target and the actual position of the right end of the cross member 5, a difference signal appears at the output of the comparator unit 23, which with the help of digit 50

Analogue converter 24 is converted from digital form to voltage. The latter is amplified in the amplifier 25, passes through the forcing link 26, when the spindle head 6 moves, the negative phase shift introduced by the motors 11 and 12 into the amplitude-phase frequency characteristics of the control system is compensated by the adjustable positive phase shift introduced by the accelerating links 21 and 26. The parameters of the remaining units of the control system are the post-motor converter 27 and are supplied to us, therefore the required performance of the electric motor 12, and it together t-rotations ispolzonie-operation systems are provided lead screw 8, which cooks vaniem-model correcting links

Chiva, raises or lowers the right frame (not shown), which are part of the cross-piece 5 in Tirisnets until the signal at the output of the comparator unit 23 becomes zero.

To set the same program of movement of both ends of the cross member 5, a control signal is supplied to both control channels from the same task input block 17. However, in the process of processing the workpieces by raising or lowering the cross member 5 along the uprights 3 and 4 due to the difference in the electromechanical constant times of the engines 11 and

another). Therefore, in order to avoid

rank 5 must accelerate (or slow down) more slowly than the right end,

synchronism of movement of the ends of the cross member 5, the forcing links 21 and 26 are introduced into the control system.

Suppose, for definiteness, that spindle head 6 has moved along crossbar 5 to the left of its middle position. Then, the reduced electromechanical time constant of the engine 11 increases, and that of the engine 12 decreases, and in dynamics the left end is transversely, however, simultaneously with the displacement of the pinings

of the common grandmother 6 is changed, and the signal from the sensor 29 of its movements is fed to the inputs of the functional converters 31 and

s2, which leads to a change in signals

s2, which leads to a change in signals

their exits. At the same time, the signal at the output of converter 31, arriving at the base of transistor 35, decreases, and the value of active resistance; 1, the collector junction of transistor 35 increases, causing an increase in the constant force forcing time 21. At the same time,

This leads to a decrease in the time constant of the forcing element 26. Due to the corresponding formation of the static characteristics (1) and (12) of the functional transducers 21 and 26, the reduced electromechanical time constants of the motors 11 and 12 constant time of the corresponding forcing links 21 and 26 are achieved. at

any position of the spindle head 6 on the crossbar 5. Thus, the change in its shape

any position of the spindle head 6 on the crossbar 5. Thus, the change in its shape

when the tailstock 6 moves, the negative phase shift introduced by the motors 11 and 12 into the amplitude-phase frequency characteristics of the control system is compensated for by the controlled positive phase shift introduced by the accelerators 21 and 26. The parameters of the remaining units of the control system are constant 10

15

7

transducers 22 and 27. As a result, the influence of the position of the spindle head 6 on the dynamic characteristics of both control channels is eliminated, and with respect to the disturbing effect considered, projection of the synchronism of movement of the ends of the cross member 5 relative to the pillars 3 and 4 for any position of the spindle head 6 on the crossbar 5.

In the case when ACS is affected by other possibilities that are not related to the change of the position of the spindle head 6 on the crossbar 5 (such opportunities are usually insignificant in size and are semi-static), for example, it shows non-identity of kinematic chains driving screws 7 and 8, it is provided to introduce a correction signal generated by the comparison unit 28 into both control channels. Suppose, for definiteness, that in the process of moving the cross member 5 upwards along the rack m 3 and 4, the left end of the cross member 5 is ahead of its right end. In this case, the readings of the sensors 13 and 14 for mixing the ends of the cross member 5 become different, and a difference signal of positive polarity appears at the output of the comparison unit 28. It is fed to the inverting input of the comparator unit 18 and the non-inverting input of the comparator unit 23, as a result of which the signal at the output of the comparator unit 18 is reduced, and at the output of the comparator unit 23 it increases. In this case, the speed of rotation of the engine 11 falls, and the speed of the engine 12 increases until the signal at the output of the comparison unit 28 becomes zero, i.e. while the coordinates are 20

thirty

Research Institute of the ends of the cross member 5 will not be equal

35

five

five

0

0

five

AND

between themselves. The process of compensating for the misalignment of the positions of the ends of the cross member 5 as it moves downward is completely analogous to that considered. In this way, the matching of the ends of the cross member 5 when processing the blanks is ensured.

Claims (1)

Invention Formula A device for synchronously mixing the working body of the machine, on which a unit movable relative to the working body is located, containing a moving unit moving sensor, a task input unit, a two-channel working unit movement control system, each channel of which includes a working body mixing sensor, comparison unit, amplifier, , a controlled power converter and a motor connected kinematically with a working body, the input block of the task being associated with the inputs of the comparison blocks of both channels, and the inverter The input input of the first comparison unit of the first channel and the non-inverting input of the second comparison unit are connected to the output of the third comparison unit, the inputs of which are connected to the working element movement sensors, characterized in that, in order to increase the dynamic accuracy, each control channel is equipped with a functional converter and a phase-wrench link variable time constant, while the phase-dependent link is connected in series between the amplifier and the controlled power converter and connected via fu The national converter with the sensor is moved11 of the mobile unit relative to the working element. Compiled by A. Semenov Editor V. Dankotehred I. VeresKorrektor T. Kolb Order 428/14 Circulation 787 Subscription VNIIPI State Committee of the USSR for Investigation of Discoveries 1 13035, Moscow, Zh-35, Raushsk nab. 4/5 Production and printing company, Uzhgorod, ul. Project, 4