CN111702549B

CN111702549B - Five-axis precise small gantry numerical control machining center with intelligent electronic balance weight

Info

Publication number: CN111702549B
Application number: CN202010649069.2A
Authority: CN
Inventors: 李爱军; 孟祥东; 殷正斌; 唐小琦; 刁思勉
Original assignee: Guangdong Pradi Technology Co Ltd
Current assignee: Guangdong Pradi Technology Co Ltd
Priority date: 2020-07-08
Filing date: 2020-07-08
Publication date: 2021-07-06
Anticipated expiration: 2040-07-08
Also published as: CN111702549A

Abstract

The invention discloses a five-axis precise small gantry numerical control machining center with an intelligent electronic counterweight. According to the method, the electronic counterweight function of the vertical shaft is realized by using the vertical shaft servo system, the electronic counterweight function is realized, the sinking of the suspension shaft can be almost completely avoided by using the electronic counterweight function, and the sinking of the counterweight shaft can be avoided when closed-loop control is activated. After the brake is released, a constant counterweight torque will maintain the position of the suspension shaft.

Description

Five-axis precise small gantry numerical control machining center with intelligent electronic balance weight

Technical Field

The invention relates to the field of machine tool digital control, in particular to a five-axis precise small gantry numerical control machining center with an intelligent electronic counterweight.

Background

When the numerical control machine tool is used for high-speed machining, the stability of the gravity shaft of the machine tool is guaranteed, and the stability plays an important role in high precision of a machined part. When the shaft moves upwards, the direction of the motor thrust is the same as that of gravity; when the shaft moves downwards, the thrust direction of the motor is opposite to the gravity. In the past, a transmission member such as a screw is easily worn on one side, and stability of machine tool precision is affected. Particularly for a ball screw without self-locking property, if the brake is released and the weight of the gravity shaft is insufficient, the gravity shaft can accidentally fall, as shown in fig. 1, the brake holds the z shaft, the brake is released, the servo is enabled, the pulse is enabled, the z shaft descends, and the shaft is stopped at a specified position by closed-loop control later. The vertical shaft of the numerical control machine tool is weighted to prevent the gravity shaft from falling, the effect is shown in figure 2, the brake holds the z shaft, the brake is released, the servo is enabled, the torque can be configured in a pulse mode, the z shaft is in place, the load of a vertical shaft screw rod and a motor of the machine tool can be reduced, the machining precision is improved, and the service life of the machine tool is prolonged.

When the existing hydraulic or mechanical counterweight moves to a stop at a high speed of the vertical shaft, the vertical shaft sags due to gravity because of the reasons of low response speed of the hydraulic or mechanical counterweight, insufficient counterweight balance degree and the like, so that the machining precision is influenced, even faults occur, and an additional structure is required.

Disclosure of Invention

Based on the problems existing in the technical background, the invention provides an intelligent electronic counterweight method, which adopts a vertical axis servo driving system to develop the vertical axis electronic counterweight function and improve the counterweight precision and reliability.

The present invention is directed to solving at least one of the problems of the prior art. Therefore, the invention discloses a five-axis precise small gantry numerical control machining center with an intelligent electronic counterweight.

Furthermore, the difference value of the torque of the upward and downward movement of different zone sections is measured and used as an electronic counterweight value to accurately balance the weight, and different electronic counterweights are applied in different movement directions of the vertical shaft.

Further, when the gravity shaft moves downwards, the value of the additional torque is increased to overcome the falling of the gravity shaft when the power supply of the machine tool is suddenly cut off.

Further, when the gravitational force moves axially upward, the magnitude of the additional torque is decreased.

Furthermore, the difference of the shaft movement direction is judged through the related interface signals, and different values are given to the driving parameters P1511 or P1513 in the PLC program. To reduce the counterweight step after brake release, the torque offset value is interconnected as a torque addition setpoint (p1511 or p1513) to achieve immediate setting of holding torque after brake release, where the relevant interfaces are db3n.dbx64.6, db3n.dbx64.7, n = [1,2, … … n ].

Furthermore, the value of the electronic counterweight is modified in real time in a Numerical Control (Numerical Control) program, and the torque value of each section of the gravity shaft area read by a Programmable Logic Controller (PLC) is read and stored in a Numerical Control program file through a data exchange area of the PLC and the Numerical Control program, or the electronic counterweight value stored in the Numerical Control program file is written into a driver by the PLC.

Furthermore, when the torque output in the gravity shaft movement needs to be read, a first program in a numerical control program is operated, a real number array is defined in the first program, an M command in the numerical control program activates an FB2 function in the PLC, the torque value of each area of the gravity shaft is read through the B2 function, the torque value is written into a data exchange area $ A _ DBR [ n ] of the PLC and the numerical control program, the torque value is stored in the real number array, and the torque value is written into a file by a Write command.

Furthermore, before dynamically setting the electronic counterweight value, a second program in the numerical control program is operated, wherein the second program comprises 2 real number arrays, one real number array stores electronic counterweight values in different areas when the gravity axis moves downwards, the other array contains electronic counterweight values in different areas when the gravity axis moves upwards, and the 2 real number arrays are input into a PLC storage area through a self-defined M instruction, wherein in the areas when the gravity axis moves differently, the PLC calls an FB3 function to give different values to P1511 or P1512, so that the function of accurately controlling the electronic counterweight is realized.

The invention further discloses an electronic device comprising:

a processor; and the number of the first and second groups,

a memory for storing executable instructions of the processor;

wherein the processor is configured to execute the intelligent electronic counterweight method of the five-axis precision mini-gantry numerically controlled machining center with the intelligent electronic counterweight via execution of the executable instructions.

The invention further discloses a computer readable storage medium, on which a computer program is stored, which when executed by a processor implements the intelligent electronic counterweight method of the five-axis precise mini-gantry numerical control machining center with the intelligent electronic counterweight.

Compared with the prior art, the method has the advantages that the electronic counterweight function of the vertical shaft is realized by using the vertical shaft servo system, the electronic counterweight function is realized, the sinking of the suspension shaft can be almost completely avoided by using the electronic counterweight function, and the sinking of the counterweight shaft can be avoided when closed-loop control is activated. After the brake is released, a constant counterweight torque will maintain the position of the suspension shaft.

Drawings

The invention will be further understood from the following description in conjunction with the accompanying drawings. The components in the figures are not necessarily to scale, emphasis instead being placed upon illustrating the principles of the embodiments. In the drawings, like reference numerals designate corresponding parts throughout the different views.

Fig. 1 is a schematic diagram of a gravity shaft falling caused by insufficient counterweight of the gravity shaft in the prior art.

Fig. 2 is a schematic diagram of a vertical axis of a machine tool being weighted to prevent a gravity axis from falling.

Fig. 3 is a control flow chart of an intelligent electronic counterweight method based on a gravity axis of a machine tool.

Detailed Description

Example one

In the control flow of the intelligent electronic balancing method based on the gravity axis of the machine tool as shown in fig. 3, on the vertical axis without hydraulic or mechanical balancing, the electronic balancing weight is set by the torque limit offset in the vertical axis servo system, so that the upper torque limit and the lower torque limit of the vertical axis servo are translated according to the offset value.

To illustrate, different electronic weights are applied with different directions of motion of the vertical axis. When the gravity shaft moves downwards, the value of the additional torque needs to be larger, and the additional torque is used for overcoming the falling of the gravity shaft when the power supply of the machine tool is suddenly cut off. When the gravitational force moves axially, the magnitude of the additional torque can be small due to inertia during the movement. Meanwhile, different values of the electronic counter weights are adopted in different movement directions, so that the single-side abrasion of the transmission part is avoided, and a good effect is achieved.

To explain further, the electronic weight values of different regions are different. Due to tolerances in machine parts, variations in the assembler, the gravity shaft cannot maintain a constant torque over the full stroke. And measuring the difference value of the torques of the upward and downward movements of the different area sections as an electronic counterweight value to ensure more accurate counterweight.

To illustrate further, the value of the electronic weight is modified in real time in a Numerical Control (Numerical Control) program. Through a data exchange area between a PLC (Programmable Logic Controller) and an NC (numerical control), torque values of each section of the gravity shaft area read by the PLC are read out and stored into an NC file, or electronic weight values stored in the NC file are written into a driver by the PLC. The counterweight numerical value is conveniently modified in the NC program file instead of the PLC, so that the operation is simple and convenient.

According to the method, the electronic counterweight function of the vertical shaft is realized by using the vertical shaft servo system, the electronic counterweight function is realized, the sinking of the suspension shaft can be almost completely avoided by using the electronic counterweight function, and the sinking of the counterweight shaft can be avoided when closed-loop control is activated. After the brake is released, a constant counterweight torque will maintain the position of the suspension shaft.

Example two

When the numerical control machine tool is used for high-speed machining, the stability of the gravity shaft of the machine tool is guaranteed, and the high-precision machining method plays an important role in the high precision of the machined part. When the shaft moves upwards, the direction of the motor thrust is the same as that of gravity; when the shaft moves downwards, the thrust direction of the motor is opposite to the gravity. In the past, a transmission member such as a screw is easily worn on one side, and stability of machine tool precision is affected. Especially for ball screws without self-locking characteristics, if the gravity shaft counter weight is insufficient when the brake is released, the gravity shaft can accidentally fall. Therefore, we have chosen the S120 driver from Siemens and have chosen the "electronic weight" function.

On a vertical axis without mechanical counterweights, electrical counterweights can be placed by torque limit offset (p 1532). p1520 (upper torque limit) and p1521 (lower torque limit) will be translated by this offset value. The offset value may be read from r0031 and transferred into p 1532.

To reduce the weight step after releasing the brake, the torque offset value may be interconnected as a torque addition set value (p1511 or p1513) so that the holding torque can be given directly after the brake is released.

This example illustrates the improvement of the present invention over the prior art, mainly from the following three points:

1. different directions of motion apply different electronic weights (additional torque).

The difference in the direction of the shaft movement is detected by the relevant interface signals (db3n.dbx64.6, db3n.dbx64.7, n = [1,2, … … n ]), and different values are assigned to the drive parameters P1511 or P1513 in the PLC program.

When the gravity shaft moves downwards, the value of the additional torque needs to be larger, and the additional torque is used for overcoming the falling of the gravity shaft when the power supply of the machine tool is suddenly cut off. When the gravitational force moves axially, the magnitude of the additional torque can be small due to inertia during the movement.

Meanwhile, different values of the electronic counter weights are adopted in different movement directions, so that the single-side abrasion of the transmission part is avoided, and a good effect is achieved.

2. Difference of electronic balance weight value of different regions

Due to tolerances in machine parts, variations in the assembler, the gravity shaft cannot maintain a constant torque over the full stroke. And measuring the difference value of the torques of the upward and downward movements of the different area sections as an electronic counterweight value to ensure more accurate counterweight.

3. And reading out and storing the torque value of each section of the gravity shaft area read by the PLC into an NC file through a data exchange area of the PLC and the NC, or writing the electronic balance weight value stored in the NC file into a driver by the PLC. The aim of this is to modify the counterweight value conveniently in the NC program file, rather than in the PLC, with ease of operation.

When the output torque in the gravity shaft movement needs to be read, an NC program A is operated, a real number array is defined in the program A, an M command in the NC program activates an FB2 function in the PLC, an FB2 reads the torque value of each gravity shaft area, the torque value is written into a data exchange area $ A _ DBR [ n ] of the PLC and the NC, then the torque value is stored in the real number array in a transferring mode, and the Write command is used for writing a file.

Before dynamically setting 'electronic counterweight value', an NC program B is operated, wherein the program B comprises 2 real number arrays, one real number array comprises electronic counterweight values in different areas when the gravity axis moves downwards, the other array comprises electronic counterweight values in different areas when the gravity axis moves upwards, and the 2 real number arrays are input into a PLC storage area through a self-defined M instruction. In different areas of shaft movement, the PLC calls the FB3 function to assign different values in the array to P1511 or P1512 to control the electronic balance weight more accurately.

It should also be noted that the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising an … …" does not exclude the presence of other like elements in a process, method, article, or apparatus that comprises the element.

As will be appreciated by one skilled in the art, embodiments of the present application may be provided as a method, system, or computer program product. Accordingly, the present application may take the form of an entirely hardware embodiment, an entirely software embodiment or an embodiment combining software and hardware aspects. Furthermore, the present application may take the form of a computer program product embodied on one or more computer-usable storage media (including, but not limited to, disk storage, CD-ROM, optical storage, and the like) having computer-usable program code embodied therein.

Although the invention has been described above with reference to various embodiments, it should be understood that many changes and modifications may be made without departing from the scope of the invention. It is therefore intended that the foregoing detailed description be regarded as illustrative rather than limiting, and that it be understood that it is the following claims, including all equivalents, that are intended to define the spirit and scope of this invention. The above examples are to be construed as merely illustrative and not limitative of the remainder of the disclosure. After reading the description of the invention, the skilled person can make various changes or modifications to the invention, and these equivalent changes and modifications also fall into the scope of the invention defined by the claims.

Claims

1. A five-axis precise small gantry numerical control machining center with intelligent electronic counterweights is characterized in that the electronic counterweights are arranged in a vertical axis servo system through torque limit deviation on a vertical axis without hydraulic or mechanical counterweights, so that the upper torque limit and the lower torque limit of a vertical axis servo are translated according to the deviation value; and modifying the value of the electronic counterweight in real time in a numerical control program, reading out the torque value of each section of the gravity shaft area read by the PLC and storing the torque value into a numerical control program file through a data exchange area of the PLC and the numerical control program, or writing the electronic counterweight value stored in the numerical control program file into a driver by the PLC.

2. The five-axis precise small gantry numerical control machining center with intelligent electronic counterweight according to claim 1, wherein the difference value of the torque of upward and downward movement of different zone segments is measured and used as an electronic counterweight value to precisely balance, and different electronic counterweights are applied in different movement directions of a vertical axis.

3. The five-axis precision small gantry numerical control machining center with intelligent electronic balance weight according to claim 2, characterized in that when the gravity axis moves downwards, the value of the additional torque is increased to overcome the falling of the gravity axis when the power supply of the machine tool is suddenly cut off.

4. The five-axis precision small gantry numerically controlled machining center with intelligent electronic counterweights as claimed in claim 2, wherein the magnitude of the additional torque is reduced when the gravitational axis moves upward.

5. The five-axis precision small gantry numerical control machining center with intelligent electronic balance weight as claimed in any one of claims 2-4, characterized in that the difference of the shaft movement direction is identified by the related interface signals, different values are assigned to the driving parameters P1511 or P1513 in the PLC program, and the torque offset value is interconnected as the torque additional set value (P1511 or P1513) to reduce the balance weight step after the brake is released, so as to realize the direct setting of the holding torque after the brake is released, wherein the related interfaces are DB3n.dbx64.6, DB3n.dbx64.7, and n is [1,2, … … n ].

6. The five-axis precision small gantry numerical control machining center with intelligent electronic balance weight as claimed in claim 1, wherein when it is needed to read the output torque in the gravity axis motion, a first program in a numerical control program is run, wherein a real number array is defined in the first program, an M command in the numerical control program activates the FB2 function in the PLC, the torque value of each region of the gravity axis is read through the FB2 function, and is written into a data exchange region $ a _ DBR [ n ] of the PLC and the numerical control program, and then is saved in the real number array, and is written into a file by a Write command.

7. The five-axis precision small gantry numerical control machining center with intelligent electronic balance weight as claimed in claim 6, wherein before dynamically setting the electronic balance weight value, a second program in the numerical control program is run, the second program contains 2 real number arrays, one real number array contains electronic balance weight values in different areas when the gravity axis moves downwards, the other array contains electronic balance weight values in different areas when the gravity axis moves upwards, and the 2 real number arrays are input into a PLC storage area through a self-defined M instruction, wherein in the areas where the gravity axis moves differently, the PLC calls an FB3 function to give different values in the arrays to P1511 or P1512, so as to realize the function of precisely controlling the electronic balance weight.

8. An electronic device, comprising:

a processor; and the number of the first and second groups,

a memory for storing executable instructions of the processor;

wherein the processor is configured to execute the electronic balance weight control method of the five-axis precision small gantry numerical control machining center with intelligent electronic balance weight of any one of claims 1 to 7 through executing the executable instructions.

9. A computer-readable storage medium, on which a computer program is stored, wherein the computer program, when executed by a processor, implements the electronic counterweight control method of the five-axis precision small gantry numerically controlled machining center with intelligent electronic counterweight of any of claims 1 to 7.