SU1205130A1 - Adaptive control device for metal-cutting machine tool - Google Patents

Abstract

The invention relates to the field of automatic control and allows to increase the used effective power of the main drive electric motor (EGP) and processing performance by using the property of the electric motor to work for some time with power overload without stalling. 1 Specified maximum cutting power in the system: setpoint 1 power - first Comparison element 2 - power regulator 3 - feed restriction block 4 - feed drive 5 - control object 6 - EGP 7 - power sensor 8 - first limit switch 9 - sensor IR 10 temperature — the second amplifier 11 — the second element 12 of the comparison — the temperature controller 13 — the temperature setpoint 14 is controlled depending on the difference in the temperature of the EGP heating and its permissible temperature set by the setting unit 14. As the temperature increases to an acceptable level, the device reduces the cutting power (MR) to nominal. After a time set by regulator 13, the EGP is cooled and the MP is set to maximum. 1 3. п.ф-л, 4 Il. with b (L: l 00

Description

This invention relates to automatic control and regulation, in particular to adaptive control of cutting machines.

The purpose of the invention is to increase the use of the effective power of the main drive motor and increase the processing capacity.

Figure 1 shows the functional diagram of the device j in figure 2 - diagrams of the operation of the device; FIG. 3 shows the technical implementation of the temperature regulator / FIG. 4 is a diagram of its operation.

Adaptive control device for cutting machine (Fig. 1) QQAepsMT power setting device 1, first comparison element 2, power controller 3, feed limiting unit 4, adjustable feed drive 5, control object 6, main drive 7, power sensor 8 The first amplifier 9, the temperature sensor 10, the second amplifier 11, the second comparison element 12, the temperature controller 13, the temperature setpoint 14.

The temperature controller 13 (FIGURE 3) contains an operational amplifier 15, a first capacitor 16, a diode 17, a potentiometer 18, a first resistor 19, a zero-body 20, a second resistor 21, a second capacitor 22, the first element IS-HE 23, the second element is AND 24, relay 25, normally open contact 26.

In addition, N,., And N are the specified and actual cutting power (effective motor power),

ft.N-NorN - mismatch of the cutting power control loop,

NH and Ngon NH - nominal and maximum allowable load power of the electric motor,

L - coefficient of permissible motor overload

Mjjj- (- the setpoint of the permissible power of the load of the electric motor according to the technological conditions;

S and Sgon - the current feed and the maximum allowable feed tool and parts;

-ILS - cycle duration, lep and L-, q - duration of clean and rough processing in the cycle ,;

icu and t-c ".u tool change time and tool with the part;

five

n 5

five

0

five

0

302

Q, Qgon and QOJ. - current permissible temperature of heating of the electric motor and ambient temperature;

L0-8dop-0 - misalignment of the contour of stabilization of the heating temperature of the electric motor;

9no - null organ hysteresis loop.

The simplified part machining cycle consists (figure 2) of rough cutting, tool change -CU. (CHRISTING t-Luc cutting, tool and part change loua- In order to achieve the highest productivity, the processing in draft mode is carried out with the maximum possible cutting power (effective power of the main drive electric motor.) Considerations (cleanliness and surface roughness, tool strength, machining accuracy) are carried out with a lower cutting power than in draft mode.

The device works as follows.

In the initial state, the setting unit 14 (figure 1) sets the permissible temperature 0a to the heating of the electric motor of the main drive 7. At the beginning of operation, the temperature of this engine, measured by sensor 10, is equal to the ambient temperature QOC and much less than 9gon-. The positive difference d0-9 dop-b of the output of the comparison element 12 fully opens the temperature regulator 13, and a voltage proportional to Myop NMN where L 1.3 + 2.0 depending on the type of engine is set at its output.

Unit 1 for a specific processing mode sets the value of the specified cutting power NO (Fig. 3). Unit 1 is a divider with a variable transfer coefficient K supplied to it by the output voltage of temperature regulator 13. The gear ratio K varies from 0-1. For draft modes, usually K 1 and, therefore, in the initial state for Figure 2, No, -KMgon J n-In block 4

the limit is established — the supply of tool supplying Soon to the part is permissible.

When the device is put into operation, the voltage of the setting device 1 (Fig. 1) passes through the reference element 2, the power regulator 3 and causes the drive 5 to move the tool to the workpiece with the feed. At the moment i touches the tool with the workpiece, the main drive motor 7 is loaded, and The second input of the reference element 2 is proportional to the load power of the main drive motor. The output signal of the comparison element 2, proportional to the difference uN-IMci-N, establishes such a supply S, which ensures the loading of the main drive electric motor to a given value Mo-AMn and with some allowable adjustment error. Due to the depth And width of processing, the hardness of the material of the workpiece, the wear of the tool, the feed is continuously changing, stabilizing the loading of the electric motor at a given level (Fig. 2).

The motor of the main drive 7 under the action of the load N: N (, begins to heat up. In this case, from the point of view of the thermal state of the engine, two modes of operation of the device are possible. In the first (fig.2c1) processing time in the roughing pass with the maximum possible load, The center temperature is such that the engine temperature does not have time to reach the allowable value Soon-In this case, the output signal of the comparison element 12 is always positive (uQ 9), the temperature controller does not change its state, and the control process proceeds, as shown in FIG. .2a.

After the end of the roughing pass, when the tool is changed (time interval -tcu, in FIG. 2), the engine is somewhat cooled. After the finishing pass with the power setpoint, the engine is again heated, but its temperature still does not reach the limit Ojon. After the end of the finishing pass, the interval icyn of the tool and part change, during which the engine is again cooled, follows.

In the second mode (figure 2 (), the processing time with

12051304

possible load NO-1I

 H

that is.

that the engine is heated at some point in time to the maximum allowable temperature Qgon. In this case, the output signal of the comparison element 12 becomes equal to zero or takes a negative value (l 6 0) | and the temperature controller 13 reduces its output voltage to a value equivalent to Nc-From this point on, the No-Nn i installation and the main drive motor operate at a nominal load, and its temperature does not increase above the maximum permissible.

The timing of the operation of the device for the second mode is described in more detail in FIG. 4.

In the initial state, when black cutting (when the power setting Nj No is selected the highest;) the output of the null organ 20 with hysteresis (Fig. 3) has a zero potential, and the output of the forming circuit on the AND-NE 23 and 24 elements the logical unit from which the relay 25 is turned on (element 24 is with the active output). Divider 18 (bypass resistor 19) is set to limit the level of regulator 13 and the corresponding 1K) to.

With increasing temperature b to an acceptable level, boop works

about

the null organ 20, and using the forming circuit 23 and 24, the relay 25 is turned off for a time determined by the parameters of the resistive-capacitive circuit 21 and 22. In this case, the limit level of the regulator 13 varies from J-Nn to NH (Fig.4) . After a delay, the relay 25 is turned on again, the resistor 19 is shunted by the contact 26, and the limiting level becomes equal to J.Kn however, due to the discharge of the capacitor 16 through the diode 17 during the switching off of the relay 25, the output signal of the regulator 13 corresponds to M the signal is governed by an integral law, providing © - Qfon under varying ambient conditions. For example, the dotted curve in FIG. 4 from time 4 corresponds to a deterioration in the engine cooling conditions, a decrease in the ambient temperature 0 ° C, etc.

After completion of the rough cut (time ij in Fig. 4), the engine is cooled. B moment i null body

0

five

0

five

0

returns to its original state and is again ready for a new black cutting cycle (if it is provided by the processing technology).

2, for comparison, the dash-dotted line shows the process control process in draft mode in the known control system. As can be seen, in this case the effective cutting power does not exceed NM and, therefore, in the device, by increasing the cutting power in draft modes to Nn place a proportional increase in the working feed S, reducing machine time and, accordingly, improving processing performance.

Claims (2)

Invention Formula one . An adaptive control of the cutting machine, containing a feed restriction unit and serially connected power setting, first comparison element, power regulator, adjustable feed drive, control object, main drive, power sensor and amplifier connected to the second input of the first comparison element, and the output of the limiting unit is connected to the second input of the power controller, characterized in that, in order to increase the utilization of the effective power of the main drive electric motor and power processing capacity, a temperature ramp and serially connected temperature sensors connected to the main drive, a second amplifier, a second reference element, a J temperature controller, the output of which is connected to the power setting input and a temperature setting output connected to the second input of the second element compare. 0 2. The device according to claim 1, characterized in that the temperature controller is designed as an integrating operational amplifier, 5 whose input is connected to the first output of the second reference element and to the diode anode, and the output to the input of the power setting device and to the first extreme terminal of the potentiometer, the middle 0 the output of which is connected to the cathode of the diode, and the second end of the output through the first resistor to the negative pole of the power source, the first element in series 5 AND-NOT, the second resistor and capacitor, as well as sequentially included null-organ, the second element of IS-NOT and the relay, the input of the null-organ is connected to the second output of the second 0 comparison element, the second output of the relay coil - to the positive pole of the power source, the first and second inputs of the first element are NOT connected to the first input of the second  element NAND, the second input of which is connected to a capacitor, the second input of which is connected to the negative pole of the power source, the first resistor is bypassed normally open relay contact. Mode 1 LM / i / yj "t N P .i additional  2 R Ll t. ft wasp f-HttV. but) S) .Z