A method for installation and removal control of a ring groove rivet

Abstract

The application discloses a kind of installation and dismounting control method for ring groove rivet.It is different riveting force interval to set different current threshold by current control method, can realize the accurate control to riveting force without the aid of pressure sensor, reduce the manufacturing cost and weight of tool, and can take the same riveting effect as the aid of pressure sensor control;Automatic identification rivet method is used, the current slope in the riveting initial stage is classified, and different types of rivets can be quickly identified by machine, so that accurate riveting of rivets can be realized without repeated parameter adjustment in different rivet working conditions, greatly improving work efficiency.The application provides a kind of light-weight riveting tool, improves riveting, dismounting efficiency and precision.

Description

Technical Field

[0001] This invention belongs to the field of riveting technology, and particularly relates to the field of electric riveting tool design technology, specifically to a method for controlling the installation and disassembly of ring groove rivets. Background Technology

[0002] Known methods for installing and removing rivets include:

[0003] For example Figure 1 The single-groove short-tail rivet shown includes a collar 101, a rivet 102, an anvil 103, and a connecting workpiece 104. When installing the rivet, the power unit motor pulls 102 axially through the transmission device. At this time, the anvil 103 presses against the collar 101. When it reaches the bottom of the collar 101, it indicates that it has been installed on the workpiece and the installation is complete. Then, the motor is controlled to retract.

[0004] for Figure 2 The single-groove, single-sided rivet shown includes a sleeve (201), a rivet (202), an anvil (203), a cap (204), and a connecting workpiece (205). When the rivet (202) is installed, the motor of the power unit pulls the rivet (202) axially through the transmission device. At this time, when the anvil (203) abuts against the top of the sleeve (201), the cap (204) begins to compress and bulge. Once the sleeve (201) is fully compressed, and the anvil (203) abuts against the workpiece, the installation is complete.

[0005] like Figure 3 The disassembly of the single-groove short-tail rivet shown is as follows: 301 is a collar, 302 is the rivet, 303 is the disassembly cutter, and 304 is the connecting workpiece. When disassembling the rivet 302, the power unit motor pulls the rivet 302 axially through the transmission device, and the disassembly cutter 303 cuts the collar 301. When the collar 301 is completely cut off, it indicates that the disassembly work is completed, and the motor is controlled to retract.

[0006] Existing electric riveting tools often install rivets using pressure sensors or by controlling the riveting stroke. Using pressure sensors not only increases the size and weight of the power tool and the difficulty of assembly, but also requires calibration after prolonged use. Stroke control, on the other hand, is highly demanding in terms of operating conditions. When riveting or disassembling workpieces of varying thicknesses, repeated adjustments to the riveting stroke are necessary, significantly reducing operational efficiency. Furthermore, existing riveting tools cannot automatically identify the type of rivet. When riveting two or more types of rivets together, adjustments must be made individually, impacting riveting efficiency.

[0007] Therefore, it is desirable to provide an automatic control scheme for rivet installation that improves riveting and disassembly efficiency and accuracy while ensuring lightweight design. Summary of the Invention

[0008] This invention discloses a method for controlling the installation and removal of grooved rivets, addressing the shortcomings of existing technologies. The objective of this invention is to provide a method for controlling the installation and removal of grooved rivets that improves riveting efficiency and accuracy while reducing the weight of riveting tools.

[0009] The present invention provides the following technical solution.

[0010] A method for controlling the installation and removal of grooved rivets, including single-groove short-tailed grooved rivets and single-groove single-sided grooved rivets, characterized in that the control method includes: acquiring the phase current of the riveting tool motor, and first performing Clark transformation on the acquired phase current value, i.e.:

[0011]

[0012]

[0013] Then perform the Park transformation, that is:

[0014] I q =-I α sin(θ)+I β cos(θ)

[0015] The Q-axis current of the motor is then obtained through mean filtering;

[0016] Among them, I a I b I c A three-phase coordinate system for the motor phase currents; I α I β This is the orthogonalized rectangular coordinate system obtained after Clark transformation of the three-phase current; I q The current value is obtained by applying the Park transformation to the aforementioned rectangular coordinate system;

[0017] Set the current threshold for controlling motor operation according to the type of annular groove rivet; among them, at least set the current threshold for starting the controller to output the reversal signal and controlling the drive motor to reverse.

[0018] The motor Q-axis current obtained by mean filtering is compared with the set current threshold to control the riveting tool motor for riveting or cutting.

[0019] This invention relates to single-groove short-tail ring groove rivets; it sets current threshold A and current threshold B; wherein, current threshold A is less than current threshold B; current threshold A is the maximum current value required for the single-groove short-tail rivet to compress the collar; current threshold B is the minimum current value required for the tail tooth of the single-groove short-tail rivet to resist tensile failure.

[0020] The control process includes: during the rivet installation process, the riveting force increases linearly, the motor rotates forward and runs at the maximum current threshold A. When the anvil touches the bottom of the collar, the riveting force increases non-linearly, and the riveting current threshold rises rapidly. When the riveting current threshold exceeds the current threshold B, the controller outputs a retraction signal to control the motor to reverse and complete the riveting.

[0021] This invention targets single-groove, single-sided annular groove rivets; it sets current thresholds A, B, and C; wherein current threshold A is less than current threshold B and less than current threshold C; current threshold A is the maximum current value required for the deformation and bulging stage of the single-groove, single-sided annular groove rivet; current threshold B is the maximum current value required for the single-groove, single-sided annular groove rivet to compress the sleeve; current threshold C is the minimum current value required for the tensile failure of the tail tooth of the single-groove, single-sided annular groove rivet.

[0022] The control process includes: during the rivet installation process, the riveting force increases linearly and is divided into two stages. Stage 1 is the single-groove, single-sided rivet deformation and bulging stage, in which the motor rotates forward and runs at the maximum current threshold A. Stage 2 is the extrusion sleeve deformation stage, in which the motor runs at the maximum current threshold B. When the anvil presses against the workpiece, the riveting force increases non-linearly, and the riveting current threshold rises rapidly. When the riveting current threshold exceeds the current threshold C, the controller outputs a retraction signal to control the motor to reverse and complete the riveting.

[0023] The riveting installation method of this invention uses automatic identification or manual setting to rivet single-groove single-sided ring groove rivets or single-groove short-tail ring groove rivets.

[0024] The automatic identification and riveting method for single-groove single-sided ring groove rivets or single-groove short-tail ring groove rivets includes: at the initial stage of riveting, based on the slope change of the obtained Q-axis current, identifying the single-groove single-sided ring groove rivet or the single-groove short-tail ring groove rivet, and setting a control method to select different riveting parameters for riveting the rivet; specifically including:

[0025] In the initial stage of riveting, the change in the slope K value of the working current of a single-groove, single-sided annular groove rivet is K. a The change in the slope K value of the working current of the single-groove short-tailed annular groove rivet is related to K b ~K c Between; where K a >K b >K c ;

[0026] When the calculated slope K ≥ K a At that time, the riveting tool automatically selects to perform riveting and installation using single-groove single-sided ring groove rivets;

[0027] When the calculated slope K b >K>K cAt that time, the riveting tool automatically selects to perform riveting and installation using single-groove single-sided annular groove rivets.

[0028] This invention automatically identifies the slope changes of the Q-axis current at multiple points in the early stage of riveting, performs automatic identification, determines the riveting method after the results of multiple points are consistent, and performs riveting installation.

[0029] This invention addresses the disassembly of single-groove short-tail ring groove rivets and single-groove single-sided ring groove rivets by setting current thresholds A and B, and additionally setting rotational speed thresholds a and b. Current threshold A is greater than current threshold B, and rotational speed threshold a is less than rotational speed threshold b. Current threshold A is the minimum current value required for rivet cutting; current threshold B is the maximum current value under no-load conditions; rotational speed threshold a is the minimum rotational speed during rivet cutting; and rotational speed threshold b is greater than the minimum rotational speed during rivet cutting.

[0030] The control process includes: during the rivet removal process, the motor rotates forward and is controlled to run at the maximum current threshold A. The motor speed gradually decreases to the speed threshold a. When the removal cutter cuts the collar, the riveting force instantly becomes zero, the load drops rapidly, the motor speed rises rapidly, and the motor current drops rapidly. When the speed rises to the speed threshold b, or the current drops to the current threshold B, the controller outputs a reversal signal to control the motor to reverse and complete the removal.

[0031] In the above control process, the speed threshold comparison starts to take effect when the motor speed is lower than the speed threshold a; the current threshold comparison starts to take effect when the motor Q-axis current threshold is greater than B.

[0032] Compared with the prior art, the present invention has the following advantages:

[0033] (1) The current control method used in this invention sets different current thresholds for different riveting force ranges, which can achieve precise control of riveting force without the aid of pressure sensors, reducing the manufacturing cost and weight of tools, while achieving the same riveting effect as with the aid of pressure sensors.

[0034] (2) The automatic rivet identification method adopted in this invention classifies the current slope at the beginning of the riveting process. It can quickly identify different types of rivets automatically. When riveting different rivets, it can achieve accurate riveting without repeatedly adjusting parameters, which greatly improves work efficiency. Attached Figure Description

[0035] Figure 1 A schematic diagram of a single-groove short-tailed annular groove rivet connection;

[0036] Figure 2 This is a schematic diagram of a single-groove, single-sided annular groove rivet connection.

[0037] Figure 3 This is a schematic diagram of the disassembly of a single-groove short-tailed annular groove rivet.

[0038] Figure 4 A schematic diagram of the working current for riveting a single-groove short-tailed annular groove rivet.

[0039] Figure 5 A schematic diagram of the working current for riveting a single-groove, single-sided annular groove rivet.

[0040] Figure 6 A schematic diagram showing the working current and motor speed for disassembling a single-groove short-tailed annular groove rivet.

[0041] Figure 7 A schematic diagram showing the slope change of the working current for single-groove single-sided and single-groove short-tail annular groove rivets.

[0042] Figure 8 This is a schematic diagram of the structure of the power tool of the present invention. Detailed Implementation

[0043] The present invention will be further described below with reference to specific embodiments. These specific embodiments are further explanations of the principles of the present invention and are not intended to limit the present invention in any way. Any technology that is the same as or similar to the present invention does not exceed the scope of protection of the present invention.

[0044] Example 1:

[0045] A control method for installing single-groove short-tail ring groove rivets, the control method includes:

[0046] By collecting the phase current of the motor, the collected current value is transformed by Park and Clark, and then the Q-axis current of the motor is obtained by mean filtering. At the same time, the control method sets two current thresholds, current threshold A and current threshold B, where current threshold A is less than current threshold B. Current threshold A is the maximum current threshold required for the single-groove short-tail rivet extrusion collar, and current threshold B is the minimum current threshold required for the single-groove short-tail rivet tail tooth to resist tensile failure.

[0047] During the riveting process, the riveting force increases linearly during the riveting installation process. The motor rotates forward and runs at the maximum current threshold A. When the anvil 103 abuts against the bottom of the collar 101, the riveting force increases non-linearly. Due to the strength and delay of the feedback adjustment, the riveting current threshold will rise rapidly. When the riveting current threshold exceeds the current threshold B, the controller outputs a reversal signal to control the motor to reverse.

[0048] like Figure 1 , Figure 4 As shown; this example uses riveting. Figure 1Taking the single-groove short-tail ring groove rivet shown as an example, the Q-axis current is calculated from the phase current. The set current thresholds A and B are both Q-axis currents, where A is set to 27A and B is set to 31A. When the anvil 103 begins to press the collar 101, the force increases linearly during the pressing process. The controller controls the motor to always keep the operating current within the value of A. When the anvil 103 moves forward to press the collar 101 to the bottom, the collar 101 is difficult to press because the bottom is close to the workpiece and the tensile strength of the tail tooth of the nail 102 is much greater than the riveting force, so the riveting force will rise sharply. At this time, the Q-axis current will also rise sharply in a short period of time. When the Q-axis current is detected to be greater than the set current threshold B, it is considered that the required riveting effect has been achieved, and the controller controls the motor to reverse and retract.

[0049] Example 2:

[0050] A control method for installing single-groove, single-sided ring groove rivets, the control method including:

[0051] By collecting the phase current of the motor, the collected current value is subjected to Clark and Park transformations, and then the Q-axis current of the motor is obtained by mean filtering. At the same time, the control method sets three current thresholds: current threshold A, current threshold B, and current threshold C. Among them, current threshold A is less than current threshold B and less than current threshold C. Current threshold A is the maximum current threshold required for the deformation and bulging stage of the 204 rivet, current threshold B is the maximum current threshold required for the single-groove single-sided rivet extrusion sleeve 201, and current threshold C is the minimum current threshold required for the tensile failure of the single-groove single-sided rivet tail tooth.

[0052] During the control process, the riveting force increases linearly during rivet installation and is divided into two stages. Stage 1 is the deformation and bulging stage of the single-groove single-sided cap 204, in which the motor rotates forward and operates at the maximum current threshold A. Stage 2 is the deformation stage of the extruded sleeve 201, in which the motor operates at the maximum current threshold B. When the anvil 203 presses against the workpiece 205, the riveting force increases non-linearly. Due to the strength and delay of the feedback adjustment, the riveting current will rise rapidly. When the riveting current exceeds the current threshold C, the controller outputs a retraction signal to control the motor to reverse.

[0053] like Figure 2 , Figure 5 As shown, this example uses Figure 2Taking the single-groove, single-sided annular groove rivet as an example. Similar to Example 1, the current thresholds A, B, and C are all Q-axis currents, where A is 28A, B is 32A, and C is 37A. When the anvil 203 abuts against the cap 201, the cap 204 begins to deform and bulge. The controller controls the motor's operating current to the maximum of 28A. As the riveting progresses, after the cap 204 has deformed and bulged, the anvil 203 begins to squeeze the sleeve 201. At this time, the controller controls the motor's operating current to 32A. When the anvil 203 moves to the bottom of the sleeve 201, that is, when it contacts the workpiece, since the workpiece is difficult to deform and the tensile strength of the tail tooth of the rivet 202 is much greater than the riveting force, the riveting force will rise sharply, and the Q-axis current will also rise sharply. When the Q-axis current is detected to be greater than the current threshold C, it is considered that the required riveting effect has been achieved, and the controller controls the motor to reverse and retract.

[0054] Example 3:

[0055] A control method for disassembling single-groove short-tail ring groove rivets, the control method including:

[0056] The method involves collecting motor phase currents, performing Clark and Park transformations on the collected current values, and then using mean filtering to obtain the motor's Q-axis current. The control method calculates the motor speed in real time using the motor's Hall effect signals. Simultaneously, the control method sets two judgment conditions to improve disassembly accuracy and reduce damage to the workpiece: a current threshold A and a current threshold B, and a speed threshold a and a speed threshold b. Current threshold A is greater than current threshold B, and speed threshold a is less than speed threshold b. Current threshold A is the minimum current value required for rivet cutting; current threshold B is the maximum current value under no-load conditions; speed threshold a is the minimum speed during rivet cutting; and speed threshold b is greater than the minimum speed during rivet cutting.

[0057] During the rivet disassembly process, the motor rotates forward and is controlled to run at the maximum current threshold A. The motor speed gradually decreases to the speed threshold a. When the disassembly cutter 303 cuts off the single-groove short-tail rivet collar 301, the riveting force instantly becomes zero, the load drops rapidly, the motor speed rises rapidly, and the motor current drops rapidly. When the current drops to the current threshold B, or the speed rises to the speed threshold b, the controller outputs a reversal signal to control the motor to reverse.

[0058] like Figure 3 , Figure 6 As shown, this example uses disassembly. Figure 3Taking the single-groove, single-sided ring groove rivet as an example, 601 represents the operating current, and 602 represents the motor speed. Similar to Example 1, the set current thresholds A and B are both Q-axis currents, where A is 38A and B is 10A; the set speed thresholds a and b are 3000 r / min and 3500 r / min, respectively. During disassembly, as... Figure 6 As shown, when the disassembly cutter head 303 contacts the collar 301, the working current gradually increases to the current threshold A, and the speed gradually decreases to the speed threshold a. When the disassembly cutter head 303 cuts the collar 301, the working current instantly decreases to the current threshold B, or the speed instantly increases to the speed threshold b. At this time, the controller determines that the disassembly is complete, controls the motor to reverse and return to the origin.

[0059] Example 4:

[0060] An automatic rivet identification method includes comparing the slope change of the Q-axis current during the initial stage of riveting to distinguish between single-groove single-sided rivets and single-groove short-tail rivets. During the initial stage of riveting, the operating current is small and has not reached the current closed-loop condition; at this time, the current is in an open-loop state. The change in operating current at this stage varies with the riveting force and has no impact on the subsequent judgment of whether the riveting is qualified.

[0061] like Figure 7 As shown, in the initial stage of riveting, the slope K value of a single-groove single-sided rivet remains around K1, while the current slope K value of a single-groove short-tail rivet varies between K2 and K3. Due to the varying riveting force characteristics of these two types of rivets, K1 is always greater than (K2 to K3). Therefore, this method is used to determine whether the rivet is a single-groove single-sided rivet or a single-groove short-tail rivet, and the controller selects the corresponding riveting parameters accordingly. Simultaneously, to avoid errors caused by current sampling interference and ensure the accuracy of the judgment, a multi-point, multiple-time sampling and comparison method will be used to minimize the impact of current sampling errors.

[0062] This invention provides an electric tool for implementing the above-described control method, such as... Figure 8 As shown, Figure 8The diagram shows the structure of the power tool of the present invention. The power tool includes: a rivet mounting or dismounting gun head 801, a ball screw 802, a secondary reduction mechanism 803, a primary reduction mechanism 804, a motor 805, a human-machine interface system 806, a controller 807, and a battery 808. The battery 808 supplies power to the controller 807, which controls the motor 805 to drive the primary reduction mechanism 804 to rotate radially. The radial rotation force is then converted into axial movement force by the secondary reduction mechanism 803 and the ball screw 802, thereby driving the gun head 801 to move back and forth. The human-machine interface system 806 can select different modes according to actual needs, including a manual judgment mode and an automatic judgment mode.

Claims

1. A method for controlling the installation and removal of grooved rivets, the grooved rivets including single-groove short-tail type grooved rivets and single-groove single-sided type grooved rivets, characterized in that, The control method includes: acquiring the phase current of the riveting tool motor, and first performing Clark transformation on the acquired phase current value, that is: Then perform the Park transformation, that is: The Q-axis current of the motor is then obtained through mean filtering; Among them, I a I b I c A three-phase coordinate system for the motor phase currents; I α I β This is the orthogonalized rectangular coordinate system obtained after Clark transformation of the three-phase current; I q The current value is obtained by applying the Park transformation to the aforementioned rectangular coordinate system; Set the current threshold for controlling motor operation according to the type of annular groove rivet; among them, at least set the current threshold for starting the controller to output the reversing signal and controlling the drive motor to reverse. The motor Q-axis current obtained by mean filtering is compared with the set current threshold to control the riveting tool motor to perform riveting or cutting. The riveting installation employs automatic identification or manual setting for riveting single-groove single-sided ring groove rivets or single-groove short-tail ring groove rivets. The automatic identification method for riveting single-groove single-sided ring groove rivets or single-groove short-tail ring groove rivets includes: at the initial stage of riveting, based on the slope change of the obtained Q-axis current, identifying the single-groove single-sided ring groove rivet or single-groove short-tail ring groove rivet and setting a control method, selecting different riveting parameters to rivet the rivet; specifically including: In the initial stage of riveting, the change in the slope K value of the working current of a single-groove, single-sided annular groove rivet is K. a The change in the slope K value of the working current of the single-groove short-tailed annular groove rivet is related to K b ~K c Between, where K a >K b >K c ; When the calculated slope K ≥ K a At that time, the riveting tool automatically selects to perform riveting and installation using single-groove single-sided ring groove rivets; When the calculated slope K b >K>K c At that time, the riveting tool automatically selects to perform riveting and installation using single-groove single-sided annular groove rivets.

2. The method for controlling the installation and removal of ring groove rivets according to claim 1, characterized in that: For single-groove short-tail ring groove rivets, current thresholds A and B are set; wherein, current threshold A is less than current threshold B; current threshold A is the maximum current value required for the single-groove short-tail rivet to compress the collar; current threshold B is the minimum current value required for the single-groove short-tail rivet to resist tensile failure. The control process includes: during the rivet installation process, the riveting force increases linearly, the motor rotates forward and runs at the maximum current threshold A. When the anvil touches the bottom of the collar, the riveting force increases non-linearly, and the riveting current threshold rises rapidly. When the riveting current threshold exceeds the current threshold B, the controller outputs a retraction signal to control the motor to reverse and complete the riveting.

3. The method for controlling the installation and removal of ring groove rivets according to claim 1, characterized in that: For single-groove, single-sided annular groove rivets, current thresholds A, B, and C are set; where current threshold A is less than current threshold B and less than current threshold C; current threshold A is the maximum current value required for the deformation and bulging stage of the single-groove, single-sided annular groove rivet; current threshold B is the maximum current value required for the single-groove, single-sided annular groove rivet to compress the sleeve; and current threshold C is the minimum current value required for the tensile failure of the tail tooth of the single-groove, single-sided annular groove rivet. The control process includes: during the rivet installation process, the riveting force increases linearly and is divided into two stages. Stage 1 is the single-groove, single-sided rivet deformation and bulging stage, in which the motor rotates forward and runs at the maximum current threshold A. Stage 2 is the extrusion sleeve deformation stage, in which the motor runs at the maximum current threshold B. When the anvil presses against the workpiece, the riveting force increases non-linearly, and the riveting current threshold rises rapidly. When the riveting current threshold exceeds the current threshold C, the controller outputs a retraction signal to control the motor to reverse and complete the riveting.

4. The method for controlling the installation and removal of ring groove rivets according to claim 2 or 3, characterized in that: At the initial stage of riveting, the slope changes of Q-axis current at multiple points are collected and automatically identified. After the results of multiple points are consistent, the riveting method is determined and the riveting installation is carried out.

5. The method for controlling the installation and removal of ring groove rivets according to claim 1, characterized in that: For the disassembly of single-groove short-tail ring groove rivets and single-groove single-sided ring groove rivets, current thresholds A and B are set, and speed thresholds a and b are added. Current threshold A is greater than current threshold B, and speed threshold a is less than speed threshold b. Current threshold A is the minimum current value required for rivet cutting; current threshold B is the maximum current value under no-load conditions; speed threshold a is the minimum speed during rivet cutting; and speed threshold b is greater than the minimum speed during rivet cutting. The control process includes: during the rivet removal process, the motor rotates forward and is controlled to run at the maximum current threshold A. The motor speed gradually decreases to the speed threshold a. When the removal cutter cuts the collar, the riveting force instantly becomes zero, the load drops rapidly, the motor speed rises rapidly, and the motor current drops rapidly. When the speed rises to the speed threshold b, or the current drops to the current threshold B, the controller outputs a reversal signal to control the motor to reverse and complete the removal.

6. The method for controlling the installation and removal of ring groove rivets according to claim 5, characterized in that: During the control process, the speed threshold comparison begins when the motor speed is lower than the speed threshold a; the current threshold comparison begins when the motor Q-axis current threshold is greater than B.

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