SU1500995A1 - Method of limiting vibration of process system - Google Patents

Abstract

This invention relates to adaptive control of cutting machines. The purpose of the invention is to increase the productivity of processing during the passage of vibration-resistant cutting areas. A method for limiting the vibrations of the AIDS system, whereby with the vibrations of the AIDS system with an amplitude less than the allowable value, the cutting power is stabilized at a given level by controlling the feed according to the integral law as a function of the difference between the specified and current cutting power values. Additionally, when passing vibration-resistant cutting areas after reducing the set level of cutting power stabilization, the path and feed values are recorded, and then the cutting depth is reduced to the value at which the feed increased relative to the original recorded value by 2 ^{1 / XS} times, where X is the degree of feed rate in the power dependence of the cutting power on the cutting parameters, increase the level of power stabilization to the initial one and cut the reduced machining allowance, at a speed of the strokes return to the point of the fixed value of the cutting path and cut off the remaining machining allowance with the preset power stabilization level. 5 il.

Description

31500995

Fig, 5 is an example of a device that implements the proposed method.

Before cutting, the tool approaches the workpiece at the maximum feed.

five

the machining allowance h will be divided by two and the adjusting movement along coordinate 2 will cease (t "2.3 5 in FIG. 1.2 and the time interval

f / Hc-Ko. calculated on the basis of dina- on figo3) „The level S of the calculating tool durability (t. 0.1 of fig. 1, 2, time interval О - tg ON figfz). At time t ,, the infeed is reduced to a level S, at which the current value of the cutting power is equal to

unknown advance processing allowance h, value

for this

 --x --- - - - - v - t - firvn а,%

S can be determined from the well-known cutting power equation

(ABOUT

N C "li, N

about

c after fixing level 3, the movement of Z - is simultaneously fixed. Next, set the level of power stabilization to the initial NJJ value (toZ, 4 in FIG. 1.2 and time interval t –t in FIG. 3) and cut off the reduced processing allowance with higher power setpoints.

15 and, respectively, of the filing (t „4 according to figs 1.2 and the time interval .- b according to fig.3”)

After cutting the reduced allowance, the cutting power is reduced to

where is S.

- constant AND exponent indicators, depending on the material of the workpiece and tool; B is the cutting width (in the case under consideration constant) h is the depth of cut; D, Z - diameter of the tool and the number of his / teeth

In the event of vibrations exceeding the allowable value, the level of stabilization of the cutting power, and consequently, the feed rate, decreases. At some level N. and feed

 one

the amplitude of the vibrations becomes less than the allowable value; this level is fixed

Ac

S, (N.

Xj

.

also fixed (v.2 in FIG. 1, 1, 2, time intervals t - t according to fig. 3). Simultaneously, the value of the path of the cutting paths is taken. Ann 1 1 ,, passed by the tool in the workpiece. on the Z coordinate of the machine. In order to divide the unknown machining allowance into two, it is necessary to control the change in feed rate as the depth decreases due to the cutting power stabilization system. At some level

ZN,.

S, (.

V j

  Z

.) Z

the machining allowance h will be divided by two and the adjusting movement along coordinate 2 will stop (t 2,3 2.3 in FIG. 1.2 and the time interval

in fig.3). The level S is calculated after fixing level 3, and the movement of Z - is simultaneously recorded. Next, the power stabilization level is increased to the initial NJJ value (T3, 4 in FIG. 1.2 and the time interval t -t in FIG. 3) and the reduced processing allowance is cut off with higher values of the power setting and, accordingly, the supply (t „4 in FIG. 1.2 and the time interval. - b in FIG. 3) „

After cutting the reduced allowance, the cutting power is reduced to

the no-load level (t, 5 in figo1, 2 and time instant ty in figoZ) and

the cutting path 1 is fixed with a reduced allowance h, b, which is defined as the total cutting path from the moment of contact with the workpiece minus the previously fixed cutting path 1 with full allowance h (Fig. "1). At the moment (tg in FIG. 3) command for reversing the feed on the coordinate -X at high speed S "After passing the path equal to Ij (t, 6 in Fig. 2), the feed at the coordinate X stops and the feed of the high speed at coordinate

Z (t, 6.7 pfig, 152) to move d2. After processing the move - d Z, the feed at the Z coordinate is stopped and a command is given to move along the X coordinate at the feed

restrictions s. "After insertion, the feed is reduced to the level at which the current value of the cutting power

VII is equal to the specified level N, and the remaining treatment allowance is cut (t ,, 7 - 10 in FIG. I, 2 and the time interval t - t in FIG. 3). When the allowance changes (that is 8.9 in time and the instant of time t according to FNGOS), the feed changes, stabilizing the cutting power at a given level

The method can be implemented in various ways, both in hardware and in software (in a microprocessor CNC device). The device in software and hardware is depicted in FIG.

The device contains a control program input unit (UE) 1, a buffer unit 2, a control generation unit 3

reduced by / glcha GI, A. ribations. In HCKOTopi.yfi, the moment is set: - Wits ratio. Log-icic unit 27 5 is controlled from; one hundred g {and. g, i, n 1.1 p l D) and typing commands for the subcontractors; block 31 for calculating additional frames and in block 30; memory; block 30; naNrsiTvi fixes

ten

1VDH signals, 4.5 units of comparison, digital regulators 6.7, digital-analog converters 8.9, drives 10, 11 of the machine feed, sensors 12.13 feedback along the way, analog-digital converters 14.15, machine 16, a power sensor 17, a vibration sensor 18, analog-digital converters 19, 20, comparison blocks 21, 22, power controllers and level 24 memorize the current value of a coherent vibration, block 25 of the library of typical cutting modes Blocks 21-25 are the digital part 26 of the adaptive control system, logical blocks 27-29, memory block 30 and block 31 the calculation of the Additional frames is included in block 32 of the formation of the trajectory of

The device works as follows

In the preparatory frame, the input unit 1 enters the required geometrical information of the working frame into the buffer unit 2 and the required technological information (data about the tool, machined parts, cutting modes) in the 25o block. In block 25 in the preparatory frame based on TexHonor The i4ecKHX UE data calculates the necessary parameters for the operation of the adaptive control system: maximum output20

Nata X X and in accordance with the previously established control subroutine gives the command to move along the Z coordinate in the required direction through block 3. The feed rate for the Z coordinate is set the same as for the main X coordinate:

  Sx

at the same time, working off of the working frame (comrade, movement along the X coordinate) does not stop. When the tool position changes along the Z 25 coordinate, the cutting depth decreases, and as a result, to maintain the specified power level, the N - LT doesn’t change the feed. As soon as the current feed level becomes paBHbiNf S In what is fixed by block 28, the last

thirty

sends a command to stop moving along the Z coordinate and fixing the actual Z position to Z in block 31 (the end of the first additional frame).

charter

S, i “,,,. . power setting N

WKt

permissible vibration level A, coefficient o Simultaneously, geometric information is entered into block 31 for calculating additional frames about the quality trajectory of tool movement in additional frames (without taking into account specific displacement values that are refined during operation),

In the workframe, the actuator 11 processes the displacement X. When a tool is inserted into the part, the cutting power S appears, monitored by the sensor 1 7 o

The actual value of N is compared with Nj - N

in the control signal generation unit 3, the feed rate S is amplified so that N Ng N.

With a higher level of vibration

given by N N, the difference using the 23 D controller

And the allowable level A of the regulator 24 reduces the power setting of N3 which becomes less than the initial set level NQ, while

6

reduced by / glcha GI, A. ribations. In HCKOTopi.yfi, the moment is set: - Wits ratio. Log-icic unit 27 5 is controlled from; one hundred g {and. g, i, n 1.1 p l D) and typing commands for the subcontractors; block 31 for calculating additional frames and in block 30; memory; block 30; naNrsiTvi fixes

remembers the current value of the copdn-) 10

remembers current value

0

Nata X X and in accordance with the previously established control subroutine gives the command to move along the Z coordinate in the required direction through block 3. The feed rate for the Z coordinate is set the same as for the main X coordinate:

  Sx

at the same time, working off of the working frame (comrade, movement along the X coordinate) does not stop. When the tool position changes along the Z 5 coordinate, the cutting depth decreases, and as a result, to maintain the specified power level, the N - LT doesn’t change the feed. As soon as the current feed becomes paBHbiNf S 2 In what is fixed by block 28, the last

0

0

five

gives the command to stop moving along the Z coordinate and fixing the actual Z position Z to block 31 (the end of the first additional frame).

After that, the working of the working frame along the X coordinate with a reduced processing allowance, excluding the occurrence of unacceptable vibrations, continues. The power setting N, in this case, increases to the initial value N and the feed even more increases. When cutting a reduced allowance of processing, which is fixed by block 29, the latter gives a command to block 31 to stop working the working frame, remembering the current value of X X ,, at this moment and

on-frame

0

the second addition to work

The second additional frame has the following program: return on an accelerated course along the X coordinate to the position X X (movement LH

five

 X,

2 - X,) AND BEFORE the initial position Zg BY the Z coordinate (displacement Z Z, - Z). At the same time, in the buffer device 2, the desired position of the working frame (coordinates

z z, X

a) working frame is back in operation, ensuring

- o includes

cutting off the remaining machining allowance without vibrations with the initial power setting N, K. 3 o

Claims (1)

Invention Formula A method for limiting vibrations of a technological system whereby at vibrations of a technological system with an amplitude less than the allowable value, the cutting power is stabilized at a given level by controlling the feed according to the integral law as a function of the difference between the specified and current values of the cutting power, and if vibrations occur, the specified value decreases the cutting power level of another value, at which the vibrations do not exceed the permissible value, after passing the nibro-resistant area n Witzlaus level stabilized moschnocti cutting zadanno- to its former level, characterized By the fact that, in order to increase the machining productivity when passing vibration-resistant cutting sites, after reducing the preset level of cutting power stabilization, the values of the traversed path and feed are recorded, and then the cutting depth is reduced to the value at which the feed increases relative to the fixed value of times where Xg is an exponent when feeding in the power dependence of the cutting power on the cutting parameters, increase the level of cutting power stabilization to the original specified value and Cutting the reduced machining allowance, after reducing the stabilized cutting power to the idle level at high speed, returns to the point of the fixed value of the cutting path and cutting off the remaining machining allowance with the specified level of cutting power stabilization. Phi1.1 four  250 Fi &. r-g / l Wf .  fi.ft a zoMKH $ MM / MOH