A device and method for automatic calibration of servo press position

Abstract

The present invention belongs to the fields of control technology and metal forming technology, and specifically relates to a device and method for automatic position calibration of a servo press. The present invention installs a fine-tuning motor inside a slider, the fine-tuning motor is connected to a screw B, the screw B is connected to a fine-tuning device, and the fine-tuning device is rigidly connected to the slider: a screw position sensor is installed at the screw A of the servo press, a slider position sensor is installed at the slider, and a fine-tuning position sensor is installed at the fine-tuning device, and the measured feedback value is transmitted to the electronic control system of the servo press, and automatic measurement is achieved through a series of settings. The present invention greatly reduces the technical requirements for calibration personnel, and the accuracy and precision are greatly improved compared to existing solutions, which not only ensures safety but also saves labor.

Description

Technical Field

[0001] The invention belongs to the fields of control technology and metal forming technology, and in particular relates to a device and method for automatic position calibration of a servo press. Background Art

[0002] After the design of the connecting rod servo press is completed, it enters the trial operation stage, and a work needs to be carried out to calibrate the position of the slider and the screw rod. This work requires the analysis of the physical model and mathematical model of the transmission mechanism components of the servo press, and then record the position of the slider at the bottom dead center, and at the same time record the position of the screw rod at this time. According to the stroke setting range, the corresponding position information of the slider and the screw rod can be derived by mathematical formulas. The important information of the above two key points is written into the control system of the press, so that when the slider is at the bottom dead center, the slider position information and the screw rod position information can satisfy the corresponding relationship of the mathematical formula. The control steps and process are as described above, but during the calibration process, it is necessary to use the handwheel or button on the operating table to operate so that the main drive servo motor and the fine-tuning motor can run at the specified position. There are three disadvantages: First, since the screw of the large servo press is located at a high height from the ground, a single person cannot complete the calibration work. Two people are required to operate and record the position respectively, which is a large workload and dangerous; second, there is a possibility of data errors during the calibration process; third, the calibration personnel also need to be very familiar with the mechanical design, transmission components and models of the servo press, which has high requirements. Summary of the invention

[0003] In order to solve the deficiencies of the prior art, the present invention provides a device and method for automatically calibrating the position of a servo press.

[0004] The present invention is achieved through the following technical solutions:

[0005] A device for automatic position calibration of a servo press comprises a servo press, wherein a servo motor of the servo press is connected to a reducer and a servo driver respectively, a fine-tuning motor is installed inside a slider of the servo press, the fine-tuning motor is connected to an electronic control system of the servo press, and receives commands from the electronic control system of the servo press, the fine-tuning motor is connected to a screw rod B, the screw rod B is connected to a fine-tuning device, and the fine-tuning device is rigidly connected to the slider: a screw rod position sensor is installed at a screw rod A of the servo press, a slider position sensor is installed at a slider, a fine-tuning position sensor is installed at a fine-tuning device, and the screw rod position sensor and the slider position sensor are installed at the fine-tuning device. The sensor and the fine-tuning position sensor are connected to the servo press machine electronic control system, and the measurement feedback value is transmitted to the servo press machine electronic control system; the servo press machine electronic control system is connected to the servo driver, the servo press machine electronic control system sends control instructions to the servo driver, and can receive feedback information from the servo driver; the servo press machine electronic control system is connected to the human-computer interaction platform, and the control instructions are issued to the servo press machine electronic control system through the human-computer interaction platform, and the current calibration status is displayed; it also includes a working stopper A placed on the machining surface and a working stopper B placed on the workbench.

[0006] Furthermore, the servo press is a connecting rod type servo press.

[0007] Based on the above-mentioned servo press position automatic calibration device, a servo press position automatic calibration method includes the following steps:

[0008] Step 1: First, place the work block A on the machining surface, and place the work block B on the workbench of the servo press. Start the automatic calibration control through the human-computer interaction platform, and the servo press machine electronic control system starts to execute the automatic calibration program;

[0009] Step 2: After receiving the command from the servo press machine electronic control system, the servo driver controls the servo motor to make the screw A move downward. When the servo motor reaches the torque threshold, the lower surface position of the screw A for: ,in is the height of the working stopper A, is the height of the machined surface;

[0010] Step 3: The servo press machine electronic control system reads the current screw position A position feedback from the screw position sensor , then the difference between the feedback value of the screw position sensor and the lower surface position of screw A is , recorded as the offset of screw rod A, and stored in the memory of the servo press machine electronic control system;

[0011] Step 4: According to the corresponding relationship between the slider stroke and the position of the screw rod A, the position of the screw rod A The slider stroke position is , stored in the memory of the servo press machine electronic control system;

[0012] Step 5: After completing the above steps, the servo press machine electronic control system sends a command to the fine-tuning motor driver in the fine-tuning motor. The fine-tuning motor driver controls the fine-tuning motor to move, thereby driving the screw rod B and the fine-tuning device to move the slider downward; when the slider moves to the upper surface of the working block B and the torque of the fine-tuning motor reaches the threshold, the servo press machine electronic control system reads the feedback value of the slider position sensor as , then the difference between the slider position sensor feedback value and the slider actual position is , recorded as the slider position offset, and stored in the memory of the servo press machine electronic control system;

[0013] Step 6: In step 5, when the slider moves to the upper surface of the working block B and the torque of the fine-tuning motor reaches the threshold, the feedback value of the fine-tuning position sensor read by the servo press machine electronic control system is , then the difference between the feedback value of the fine-tuning position sensor and the mold closing height is , recorded as the offset of the fine-tuning position, where the mold closing height ;

[0014] Step 7: After step 6, the servo press machine electronic control system controls the servo driver so that the servo motor drives the screw A to move 10 mm upward in a straight line through the reducer, which is defined as the bottom dead point position of the screw A. The feedback value of the current screw position sensor is read as At the same time, the servo press machine electronic control system reads the feedback value of the slider position sensor at this time , then according to the calibrated slider position offset, the slider bottom dead center position is calculated as: , and stored in the memory of the servo press machine's electronic control system. At this point, the calibration of the three position sensors is completed.

[0015] Beneficial effects of the present invention:

[0016] 1. The technical requirements for calibration personnel are greatly reduced;

[0017] 2. The fully automatic calibration process is completed within 1 minute, and the accuracy and precision are greatly improved compared with the existing solutions;

[0018] 3. Due to the high degree of automation in the calibration process, the operational safety of the calibration engineer is more guaranteed, and there is no need for multiple people to coordinate the calibration inside the press body, which ensures safety and saves labor. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 It is a schematic diagram of the structure of the device of the present invention.

[0020] Figure 2 This is the corresponding relationship diagram between the screw position and the slider stroke.

[0021] In the figure, 1 is a screw position sensor, 2 is a screw A, 3 is a slider, 4 is a fine-tuning motor, 5 is a fine-tuning position sensor, 6 is a fine-tuning device, 7 is a slider position sensor, 8 is a screw B, 9 is a machined surface, 10 is a working block A, 11 is a reducer, 12 is a servo motor, 13 is a servo driver, 14 is a servo press machine electronic control system, 15 is a human-computer interaction platform, 16 is a working block B, 17 is a workbench, 18 is a connecting rod LA, 19 is a connecting rod LB, and 20 is a connecting rod LC. DETAILED DESCRIPTION

[0022] Specific embodiments of the present invention are given below. It should be noted that the present invention is not limited to the following specific embodiments, and all equivalent changes made on the basis of the technical solution of this application belong to the protection scope of the present invention.

[0023] The present invention includes a servo press, the power source of the servo press relies on a servo motor 12, and the servo motor 12 is connected to the reducer 11 through a mechanical rigid connection. The reducer 11 drives the screw A2 to move up and down by converting the rotational motion into a linear motion, and the screw A2 drives the connecting rod LC20 to move, so that the connecting rod LA18 and the connecting rod LB19 also follow, and finally the slider 3 can complete the up and down movement. The above structure is a conventional structure of a servo press, which will not be repeated here. A fine-tuning motor 4 is installed inside the slider 3, and the fine-tuning motor 4 is connected to the servo press machine electronic control system 14 to receive the command of the servo press machine electronic control system 14. At the same time, the fine-tuning motor 4 is connected to the screw B8 to control the movement of the screw B8, and the screw B8 is connected to the fine-tuning device 6, and the fine-tuning device 6 is rigidly connected to the slider 3. In this way, the screw B8 is controlled by the fine-tuning motor 4, and then the screw B8 drives the fine-tuning device 6, and the fine-tuning device 6 drives the slider 3, and then the movement of the slider 3 is controlled to adjust the mold closing height. The servo motor 12 mentioned above can be used to complete the stroke movement of the servo press, and the fine-tuning motor 4 is used to complete the mold adjustment movement.

[0024] The present invention installs a screw position sensor 1 at the screw A2, a slider position sensor 7 at the slider 3, and a fine-tuning position sensor 5 at the fine-tuning device 6. The above-mentioned screw position sensor 1, slider position sensor 7, and fine-tuning position sensor 5 are all connected to the servo press machine electronic control system 14, and the measurement values ​​of different positions are respectively fed back to the servo press machine electronic control system 14.

[0025] The servo press machine electronic control system 14 is connected to the servo driver 13. The servo press machine electronic control system 14 sends control instructions to the servo driver 13 and can receive feedback information from the servo driver 13. The servo driver 13 is connected to the servo motor 12 through a cable.

[0026] The servo press machine electronic control system 14 is connected to the human-machine interaction platform 15 , and control instructions are issued to the servo press machine electronic control system 14 through the human-machine interaction platform 15 , and the current calibration status is displayed.

[0027] The calibration method requires a working block A10, which is a rigid object with a known height. The height of the working block A10 is recorded as , place the working block A10 on the machined surface 9, the height of the machined surface 9 is known as .

[0028] The calibration method also requires the use of a working block B16, which is also a rigid object with a known height. The height of the working block B16 is recorded as , place the work block B16 on the workbench 17 of the servo press, take the workbench 17 as the zero reference surface, and the height of the work block That is the actual position of slider 3 at this time.

[0029] The present invention designs an automatic calibration method through the above-mentioned servo press automatic calibration device, and the specific steps are as follows:

[0030] Step 1: First, the calibration personnel puts the working block A10 on the machined surface 9 and the working block B16 on the workbench 17 of the servo press, and then starts the automatic calibration control through the human-computer interaction platform 15. At this time, the servo press machine electronic control system 14 starts to execute the automatic calibration program.

[0031] Step 2: After receiving the instruction from the servo press machine electronic control system 14, the servo driver 13 controls the servo motor 12 to make the screw rod A2 move downward. Since the working block A10 is a rigid object, when the screw rod A2 moves to the position of the working block A10, the torque of the servo motor 12 gradually increases from the ideal 0N·m (in practice, due to the existence of the balance bar, the torque is a very small value). When a certain torque threshold is reached, it can be determined that the screw rod A2 has contacted the block. The torque threshold is set in advance. The torque threshold needs to ensure that it will not cause mechanical failure and deformation. At this time, the lower surface position of the screw rod A2 It can be obtained according to the working block A10 and the machined surface 9: .

[0032] Step 3: The servo press machine electronic control system 14 reads the current screw position A2 feedback from the screw position sensor 1 , then the difference between the current feedback value of the screw position sensor 1 and the lower surface position of the screw A2 is , recorded as the offset of the screw rod A2, and stored in the memory of the servo press machine electronic control system 14.

[0033] Step 4: According to the corresponding relationship between the stroke of slider 3 and the position of screw rod A2, the position of screw rod A2 It can be obtained that the stroke position of slider 3 at this time is , stored in the memory of the servo press machine electronic control system 14.

[0034] Correspondence between the stroke of slider 3 and the position of screw rod A2 , as attached Figure 2 As shown, the horizontal axis Indicates the position of screw A2, ordinate Indicates the stroke of the slider 3. The relationship between the stroke of the slider 3 and the position of the screw rod A2 can be calculated by the connecting rod structure of the servo press itself and the position of the screw rod A2 and then derived by existing mathematical formulas, or the corresponding relationship between the two can be obtained by using mechanical dynamics simulation software. For these common knowledge, the present invention will not be described in detail here. This corresponding relationship generally exists in the form of a two-dimensional table in the memory of the servo press complete electronic control system 14. By querying this two-dimensional table, the stroke position of the slider 3 when the lower surface of the screw rod A2 contacts the working block A10 can be obtained. , and then store it in the memory of the servo press machine electronic control system 14.

[0035] Step 5: After completing the above steps, the servo press machine electronic control system 14 sends a command to the fine-tuning motor driver in the fine-tuning motor 4. The fine-tuning motor driver controls the movement of the fine-tuning motor 4, thereby driving the screw rod B8 and the fine-tuning device 6 to move the slider 3 downward. When the slider 3 moves to the upper surface of the working stop block B16, the torque of the fine-tuning motor 4 gradually increases from a small value. When it reaches the threshold, it is considered that the lower surface of the slider 3 contacts the upper surface of the working stop block B16. Similarly, the threshold is set in advance, and the threshold must ensure that it will not cause mechanical failure and deformation. At this time, the servo press machine electronic control system 14 reads the feedback value of the slider position sensor 7 as , then the difference between the feedback value of the slider position sensor 7 and the actual position of the slider 3 is , recorded as the position offset of the slider 3, and stored in the memory of the servo press machine electronic control system 14.

[0036] Step 6: In step 5, when the slider 3 moves to the upper surface of the working block B16 and the torque of the fine-tuning motor 4 reaches the threshold value, the servo press machine electronic control system 14 reads the feedback value of the fine-tuning position sensor 5 as According to the basic concept of servo press, the mold closing height is , then the difference between the feedback value of the fine-tuning position sensor 5 and the mold closing height is , recorded as the offset of the fine-tuning position.

[0037] Step 7: After step 6, the servo press machine electronic control system 14 controls the servo driver 13 so that the servo motor 12 drives the screw rod A2 to move straight upward by 10 mm through the reducer 11, which is defined as the bottom dead point position of the screw rod A2. The feedback value of the current screw rod position sensor 1 is read as , then the position relationship of the screw rod A2 is: At the same time, the servo press machine electronic control system 14 reads the feedback value of the slider position sensor 7 at this time , then according to the calibrated position offset of slider 3, the bottom dead point position of slider 3 can be calculated as: , stored in the memory of the servo press machine electronic control system 14.

[0038] At this point, the calibration of the three position sensors is completed.

[0039] The technical problem solved by the present invention is mainly to realize the fully automatic calibration process of the connecting rod servo press, which does not require any manual recording process, nor does it require the calibration personnel to be proficient in complex physical models and mathematical formula derivation processes. The only operation required by the calibration personnel is to place the working block A10 and the working block B16 used in the specified position and press the automatic calibration button of the human-computer interaction platform 15. The entire calibration process can be completed within 1 minute.

[0040] The embodiment described above is only one of the more preferred specific implementations of the present invention. Common changes and substitutions made by those skilled in the art within the scope of the technical solution of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for automatic position calibration of a servo press, based on a device for automatic position calibration of a servo press, wherein the device comprises a servo press, wherein a servo motor (12) of the servo press is respectively connected to a reducer (11) and a servo driver (13), and wherein: A fine-tuning motor (4) is installed inside the slider (3) of the servo press, and the fine-tuning motor (4) is connected to the servo press machine electronic control system (14) to receive commands from the servo press machine electronic control system (14). The fine-tuning motor (4) is connected to a screw B (8), and the screw B (8) is connected to a fine-tuning device (6). The fine-tuning device (6) is rigidly connected to the slider (3): a screw position sensor (1) is installed at the screw A (2) of the servo press, a slider position sensor (7) is installed at the slider (3), and a fine-tuning position sensor (5) is installed at the fine-tuning device (6). The screw position sensor (1), the slider position sensor (7), and the fine-tuning position sensor (5) are all connected to the servo press machine electronic control system (14). 4) connected, and transmits the measured feedback value to the servo press machine electronic control system (14); the servo press machine electronic control system (14) is connected to the servo driver (13), the servo press machine electronic control system (14) sends control instructions to the servo driver (13), and can receive feedback information from the servo driver (13); the servo press machine electronic control system (14) is connected to the human-machine interaction platform (15), and sends control instructions to the servo press machine electronic control system (14) through the human-machine interaction platform (15), and displays the current calibration status; and also includes a working stopper A (10) placed on the machined surface (9), and a working stopper B (16) placed on the workbench (17); The method for automatic calibration of the position of a servo press comprises the following steps: Step 1: first, place the working block A (10) on the machined surface (9), place the working block B (16) on the workbench (17) of the servo press, start the automatic calibration control through the human-machine interaction platform (15), and the servo press machine electronic control system (14) starts to execute the automatic calibration program; Step 2: After receiving the command from the servo press machine electronic control system (14), the servo driver (13) controls the servo motor (12) to move the screw rod A (2) downward. When the servo motor (12) reaches the torque threshold, the lower surface position of the screw rod A (2) is for: ,in is the height of the working stopper A (10), is the height of the machined surface (9); Step 3: The servo press machine electronic control system (14) reads the current screw position A (2) fed back by the screw position sensor (1) , then the difference between the feedback value of the screw position sensor (1) and the lower surface position of the screw A (2) is , recorded as the offset of the screw rod A (2), and stored in the memory of the servo press machine electronic control system (14); Step 4: Based on the correspondence between the travel of the slider (3) and the position of the screw rod A (2), the position of the screw rod A (2) The stroke position of the slider (3) at this time is obtained as , stored in the memory of the servo press machine electronic control system (14); Step 5: After the above steps are completed, the servo press machine electronic control system (14) sends a command to the fine-tuning motor driver in the fine-tuning motor (4), and the fine-tuning motor driver controls the fine-tuning motor (4) to move, thereby driving the screw rod B (8) and the fine-tuning device (6), so that the slider (3) moves downward; when the slider (3) moves to the upper surface of the working block B (16) and the torque of the fine-tuning motor (4) reaches the threshold value, the servo press machine electronic control system (14) reads the feedback value of the slider position sensor (7) , then the difference between the feedback value of the slider position sensor (7) and the actual position of the slider (3) is , recorded as the position offset of the slider (3), stored in the memory of the servo press machine electronic control system (14), the actual position of the slider (3) is the height of the working stopper B (16); Step 6: In step 5, when the slider (3) moves to the upper surface of the working block B (16) and the torque of the fine-tuning motor (4) reaches the threshold value, the servo press machine electronic control system (14) reads the feedback value of the fine-tuning position sensor (5) as follows: , then the difference between the feedback value of the fine-tuning position sensor (5) and the mold closing height is , recorded as the offset of the fine-tuning position, where the mold closing height ; Step 7: After step 6, the servo press machine electronic control system (14) controls the servo driver (13) so that the servo motor (12) drives the screw rod A (2) to move 10 mm upward in a straight line through the reducer (11), which is defined as the bottom dead point position of the screw rod A (2). The feedback value of the current screw rod position sensor (1) is read as At the same time, the servo press machine electronic control system (14) reads the feedback value of the slider position sensor (7) at this time. , then according to the calibrated position offset of the slider (3), the bottom dead point position of the slider (3) is calculated as: , and stored in the memory of the servo press machine electronic control system (14). At this point, the calibration of the three position sensors is completed.

2. The method for automatic position calibration of a servo press according to claim 1, characterized in that: The servo press is a connecting rod type servo press.

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