Bolt fastening method, hoop fastening device and computer program product

Abstract

The embodiment of the invention is suitable for the field of bolt fastening, and provides a bolt fastening method, hoop fastening equipment and a computer program product.The method comprises the steps that a plurality of motors are controlled to fasten corresponding bolts till the tightening torque of each bolt reaches the preset standard torque; detecting the parallelism of the mounting surface of the hoop; if the parallelism is larger than or equal to the preset parallelism, the spacing distances between the multiple bolts and the preset datum plane are obtained; a first bolt corresponding to the maximum value of the spacing distance, a first motor corresponding to the first bolt, a second bolt located on the opposite side of the first bolt and a second motor corresponding to the second bolt are determined; determining a deflection angle according to the deviation between the spacing distance corresponding to the first bolt and the spacing distance corresponding to the second bolt; and the first motor is controlled to unscrew the first bolt by the deflection angle, and the second motor is controlled to screw the second bolt by the deflection angle. By the adoption of the method, the connection reliability of the bolts of the hoop can be guaranteed, and the installation quality is improved.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of bolt fastening, and particularly relates to a bolt fastening method, a hoop fastening device and a computer program product. BACKGROUND

[0002] In the fields of power systems, large mechanical equipment (for example, nuclear power plant equipment), and the like, a hoop is widely used as a common connecting component to achieve reliable connection between connecting members such as conductors, pipes, and rods (for example, conductive rods). In these application scenarios, the connection quality between the hoop and the connecting member is crucial, and bolt fastening is a key link to achieve reliable connection of the hoop. If the bolt fastening effect is poor, it may cause problems such as non-parallel installation surface of the hoop, increased contact resistance, local overheating, and the like, and in severe cases, may even cause equipment failure, power interruption, and other major accidents.

[0003] In the prior art, the fastening of the hoop bolt is usually performed manually. When manually operating, the operator relies on experience and manual tools to tighten the bolt. This way is not only inefficient, but also difficult to ensure that the tightening torques of all bolts are uniform, and it is easy to cause some bolts to be too tight and some bolts to be too loose, thereby affecting the reliability of the connection and the installation quality of the hoop. SUMMARY

[0004] The embodiments of the application provide a bolt fastening method, a hoop fastening device, and a computer program product, which can solve the problem of low reliability of connection and installation quality of each bolt of the hoop.

[0005] In a first aspect, the embodiments of the application provide a bolt fastening method applied to a hoop fastening device, the hoop fastening device comprising a plurality of motors, and the plurality of motors are respectively used to output power for fastening corresponding bolts in the hoop; the method comprises:

[0006] controlling the plurality of motors to respectively fasten the corresponding bolts until the tightening torques of the bolts reach preset standard torques;

[0007] detecting parallelism of an installation surface of the hoop;

[0008] if the parallelism is greater than or equal to a preset parallelism, obtaining interval distances between a plurality of bolts and a preset reference surface, respectively;

[0009] determining a first bolt corresponding to a maximum value of the interval distances, a first motor corresponding to the first bolt, a second bolt located at an opposite side of the first bolt, and a second motor corresponding to the second bolt;

[0010] determining a deflection angle according to a deviation between the interval distance corresponding to the first bolt and the interval distance corresponding to the second bolt;

[0011] The first motor is controlled to loosen the first bolt by a deflection angle, and the second motor is controlled to tighten the second bolt by the deflection angle.

[0012] In an embodiment, the plurality of motors are controlled to respectively tighten the corresponding bolts until the tightening torque of each bolt reaches a preset standard torque, comprising:

[0013] The plurality of motors are controlled to respectively tighten the corresponding bolts at a preset rotation speed until the tightening torque of each bolt reaches a preset initial tightening torque; the initial tightening torque is less than the preset standard torque.

[0014] The plurality of motors are controlled to increase the tightening torque of each bolt from the initial tightening torque at a same torque increasing rate until the tightening torque reaches the preset standard torque.

[0015] In an embodiment, the plurality of motors are controlled to respectively tighten the corresponding bolts until the tightening torque of each bolt reaches a preset standard torque, further comprising:

[0016] During the process of controlling the plurality of motors to respectively tighten the corresponding bolts, the currents output by the plurality of motors are respectively collected.

[0017] Based on the plurality of currents, a third motor and a fourth motor are determined, which respectively output the tightening torque with a deviation; a first current corresponding to the third motor is greater than a second current corresponding to the fourth motor.

[0018] The first current output by the third motor is reduced, and the second current output by the fourth motor is increased.

[0019] The plurality of motors are controlled to respectively tighten the corresponding bolts based on the adjusted currents until the tightening torque of each bolt reaches the preset standard torque.

[0020] In an embodiment, based on the plurality of currents, a third motor and a fourth motor are determined, which respectively output the tightening torque with a deviation, comprising:

[0021] A current difference between each two currents in the plurality of currents is calculated.

[0022] A ratio between a maximum current difference in the plurality of current differences and an average value of the plurality of current differences is calculated.

[0023] If the ratio is greater than a preset ratio, the two motors corresponding to the maximum current difference are determined as the third motor and the fourth motor.

[0024] In an embodiment, after the currents output by the plurality of motors are respectively collected during the process of controlling the plurality of motors to respectively tighten the corresponding bolts, further comprising:

[0025] If there is a current that does not satisfy a preset current constraint condition, the plurality of motors are controlled to perform a target fault response action corresponding to the current constraint condition.

[0026] If the plurality of currents all satisfy the current constraint condition, based on the plurality of currents, the third motor and the fourth motor whose output tightening torques exist deviations are determined.

[0027] In an embodiment, after controlling the plurality of motors to respectively tighten the corresponding bolts until the tightening torques of the bolts reach the preset standard torques, the method comprises:

[0028] Within a preset time length, the tightening torques of the bolts are maintained as the preset standard torques.

[0029] In an embodiment, after controlling the first motor to loosen the first bolt by the deflection angle and controlling the second motor to tighten the second bolt by the deflection angle, the method further comprises:

[0030] The target step and each step after the target step are repeatedly executed until the parallelism is less than the preset parallelism; the target step is controlling the plurality of motors to respectively tighten the corresponding bolts until the tightening torques of the bolts reach the preset standard torques.

[0031] In an embodiment, after repeatedly executing the target step and each step after the target step until the parallelism is less than the preset parallelism, the method further comprises:

[0032] Detecting the contact resistance between the hoop and the connecting piece;

[0033] If the contact resistance is greater than a preset resistance, an ultrasonic vibration signal is sent to the contact surface between the hoop and the connecting piece;

[0034] After stopping sending the ultrasonic vibration signal, the target step and each step after the target step are repeatedly executed until the contact resistance is less than or equal to the preset resistance.

[0035] In a second aspect, the embodiments of the present application provide a bolt tightening device applied to a hoop tightening equipment, the hoop tightening equipment comprising a plurality of motors, the plurality of motors being respectively used to output power for tightening corresponding bolts in the hoop; the device comprises:

[0036] A first control module is configured to control the plurality of motors to respectively tighten the corresponding bolts until the tightening torques of the bolts reach preset standard torques.

[0037] A detection module is configured to detect the parallelism of a mounting surface of the hoop.

[0038] An acquisition module is configured to acquire interval distances between the plurality of bolts and a preset reference surface if the parallelism is greater than or equal to a preset parallelism.

[0039] The first determining module is configured to determine a first bolt corresponding to a maximum value of the interval distance, a first motor corresponding to the first bolt, a second bolt located at an opposite side of the first bolt, and a second motor corresponding to the second bolt;

[0040] The second determining module is configured to determine the deflection angle according to a deviation between the interval distance corresponding to the first bolt and the interval distance corresponding to the second bolt.

[0041] The second control module is configured to control the first motor to loosen the first bolt by the deflection angle, and control the second motor to tighten the second bolt by the deflection angle.

[0042] In a third aspect, an embodiment of the present application provides a hoop fastening device, which comprises a memory, a processor, a computer program stored in the memory and executable on the processor, and a plurality of motors. The processor implements the method of the first aspect when executing the computer program, so as to control the plurality of motors to respectively output power for fastening corresponding bolts in the hoop.

[0043] In a fourth aspect, an embodiment of the present application provides a computer readable storage medium, which stores a computer program. The computer program is executed by a processor to implement the method of the first aspect.

[0044] In a fifth aspect, an embodiment of the present application provides a computer program product, which, when running on a hoop fastening device, causes the hoop fastening device to implement the method of the first aspect.

[0045] Compared with the prior art, the embodiment of the present application has the beneficial effects that: the hoop fastening device can first control multiple motors to respectively fasten corresponding bolts until the tightening torque of each bolt reaches a preset standard torque, thereby ensuring the consistency of the tightening torque of each bolt, avoiding the uneven torque problem that may occur during manual fastening or simple automatic fastening, laying a foundation for subsequent parallelism detection and adjustment, and helping to improve the overall connection reliability of the hoop. Then, the parallelism of the hoop mounting surface can be detected, and when the parallelism is greater than or equal to a preset parallelism, the spacing distance between multiple bolts and a preset reference surface is measured to determine a first bolt corresponding to the maximum spacing distance, a first motor corresponding to the first bolt, a second bolt opposite the first bolt, and a second motor corresponding to the second bolt. The parallelism is usually used to measure the mounting quality of the hoop, and if the parallelism is not up to standard, it may affect the contact effect between the hoop and the connecting piece, increase the contact resistance, and cause unstable operation of the equipment. Based on this, when it is determined that the parallelism is not up to standard, the key bolts causing the parallelism to be out of tolerance, i.e., the first bolt with the maximum spacing distance and the second bolt opposite the first bolt, can be accurately determined by measuring the spacing distance between the bolts and the preset reference surface, so that the subsequent adjustment is more targeted, improving the efficiency and accuracy of the adjustment. Moreover, the opposite adjustment method can minimize the impact on the torque balance of other bolts during the adjustment process, ensuring the overall torque stability. Finally, the deflection angle is calculated based on the deviation of the spacing distance between the first bolt and the second bolt, and the first motor is controlled to loosen the first bolt by the deflection angle, and the second motor is controlled to tighten the second bolt by the deflection angle, so that the adjustment amount (deflection angle) can be accurately quantified based on the actual deviation, making the adjustment operation more accurate. Moreover, by loosening the first bolt that is too tight and tightening the second bolt that is too loose, the stress state of the hoop can be changed, thereby effectively correcting the parallelism deviation of the mounting surface and improving the accuracy of the adjustment to improve the mounting quality of the hoop. Based on this, the above-mentioned cooperative adjustment method can quickly and accurately solve the parallelism problem while ensuring that the torque of other bolts remains basically unchanged, improving the efficiency and reliability of the adjustment, and avoiding unnecessary trouble and risks caused by re-tightening all bolts or random adjustment. BRIEF DESCRIPTION OF DRAWINGS

[0046] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the following will briefly introduce the drawings needed to be used in the embodiments or prior art description. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can be obtained by those skilled in the art without creating any inventive labor.

[0047] Figure 1 is an implementation flowchart of a bolt fastening method provided by an embodiment of the present application;

[0048] Figure 2 is a schematic diagram of an implementation of a tightening torque of a bolt in a bolt fastening method provided by an embodiment of the present application to a preset standard torque;

[0049] Figure 3 is an implementation flowchart of a bolt fastening method provided by another embodiment of the present application;

[0050] Figure 4 is an implementation flowchart of a bolt fastening method provided by another embodiment of the present application;

[0051] Figure 5 is a structural schematic diagram of a bolt fastening device provided by an embodiment of the present application;

[0052] Figure 6 is a structural schematic diagram of a hoop fastening device provided by an embodiment of the present application. DETAILED DESCRIPTION

[0053] In the following description, for the purposes of explanation and not limitation, specific details are set forth, such as particular sequences of steps, techniques, etc. in order to provide a thorough understanding of the embodiments of the present application. However, it will be apparent to those skilled in the art that the present application can be practiced in other embodiments that depart from these specific details. In other instances, detailed descriptions of well-known methods, procedures, and components are omitted so as not to obscure the description of the present application with unnecessary detail.

[0054] It should be understood that the term "comprising" when used in this specification and the appended claims, indicates the presence of the described features, integers, steps, operations, elements, and / or components, but does not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and / or groups thereof.

[0055] It should be noted that the information collection process (such as patient information collection process, physiological information collection process, etc.) / feature extraction process involved in the present application is executed with the user's knowledge and permission, i.e. the information collection process / feature extraction process meets the legal and regulatory requirements and does not belong to the act of obstructing public interests.

[0056] In addition, in the description of the present application and the appended claims, the terms "first", "second", "third", etc. are only used for differentiation of description, and cannot be understood as indicating or implying relative importance.

[0057] In the field of power systems, large mechanical equipment (for example, nuclear power plant equipment), etc., as a common connecting component, the hoop is widely used to achieve reliable connection between the connecting parts such as conductors, pipes, rods (for example, conductive rods), etc. In these application scenarios, the connection quality between the hoop and the connecting part is crucial, and bolt fastening is the key link to achieve reliable connection of the hoop. If the bolt fastening effect is poor, it may cause problems such as non-parallel installation surface of the hoop, increased contact resistance, local overheating, and even serious accidents such as equipment failure, power interruption, etc.

[0058] For example, the nuclear power plant is divided into multiple functional areas (such as inside the containment, outside the containment, auxiliary plant, etc.), and each area has different requirements for safety and sealing. Electrical penetrations (for example: medium-voltage electrical penetrations, etc.) need to introduce power from one area to another without damaging the area isolation, to power equipment (such as pumps, fans, control systems, etc.). The voltage penetration includes a shell and a conductive rod, the shell is embedded in the partition structure (for example: concrete wall or metal partition, etc.) between different functional areas, and the conductive rod is used to electrically connect two functional areas. The conductive rod is electrically connected to other areas of electrical components (for example: cables, conductive plates, electrical connecting rods, etc.) through a hoop.

[0059] In the prior art, the fastening of the hoop bolt is usually manually operated. When manually operated, the operator relies on experience and manual tools to tighten the bolt. This way not only is inefficient, but also it is difficult to ensure that the tightening torque of each bolt is uniform, and it is easy to cause some bolts to be too tight and some bolts to be too loose, affecting the reliability of the connection.

[0060] Therefore, in order to ensure the reliability of the connection of each bolt of the hoop and improve the installation quality of the hoop, the embodiments of the present application provide a bolt fastening method, which can be applied to a hoop fastening device. The hoop fastening device can include a plurality of motors, and each motor is used to output power to fasten a corresponding bolt in the hoop.

[0061] As an example, the clamp fastening device can be a special fastening tool designed according to the clamp profile size, which is used to accurately position the four fastening bolt positions of the clamp. Among them, the fastening tool can adopt an upper and lower split gland structure. Upper gland: installed on one side of the hexagonal head of the clamp screw rod, with multiple sleeves (for example, four) integrated inside, each sleeve is installed on a connecting rod directly connected to the knob. The connecting rod is equipped with a ratchet mechanism (which can allow counterclockwise rotation in the tightening direction). The knob is used to manually pre-clamp the bolt head, and the ratchet mechanism acts as a counterforce arm when servo-driven. Lower gland: installed on one side of the clamp bolt nut, with multiple sleeves (for example, four) integrated inside, each sleeve is connected to an independently rotating connecting rod (for example, four independent rotating shafts). The back of the lower gland is designed with a connecting seat for connecting the power device (servo motor set). Power and control system: the power device is a plurality of independently operating motors that drive the multiple independent rotating shafts of the lower gland. The motors are controlled by a programmable logic controller for accurate torque setting and output.

[0062] Among them, the clamp is a ring-shaped clamp used to fix or connect cylindrical objects (such as pipes, power poles, shaft parts, etc.), usually composed of two semicircular or arc-shaped metal pieces, connected and fastened by bolts, and uses the clamping force to achieve clamping on the fixed object or connection with other parts (such as pipe and bracket fixation, equipment and foundation connection, etc.).

[0063] Please refer to Figure 1 , Figure 1 An implementation flowchart of a bolt fastening method provided by an embodiment of the application is shown, which includes the following steps:

[0064] S101, control multiple motors to respectively fasten corresponding bolts until the tightening torque of each bolt reaches the preset standard torque.

[0065] In an embodiment, the above-mentioned multiple motors refer to multiple servo motors equipped in the clamp fastening device. Each motor corresponds to a different bolt on the clamp, and each motor is responsible for providing power for the fastening of the corresponding bolt. Through the driving of multiple motors, independent control and synchronous operation of multiple bolts can be achieved.

[0066] Among them, the number of the above-mentioned motors can be 2, 3, 4, etc., which is not limited.

[0067] The above-mentioned fastening corresponding bolts refers to the process of rotating the bolt by motor power to tightly connect the clamp and the connecting piece together. The purpose of the fastening operation is to enable the clamp to withstand a certain load and maintain a stable connection state.

[0068] It should be noted that the specific bolt driven by each motor is the bolt corresponding to the motor. That is, in the hoop fastening device, the motor and the bolt are in a one-to-one correspondence, that is, in the fastening process, each motor only drives a specific bolt for fastening or adjustment operation.

[0069] The above tightening torque refers to the torque output by the motor during the tightening of the bolt. The tightening torque is an important indicator of the degree of bolt fastening. A suitable tightening torque can ensure the connection strength and stability of the hoop, while avoiding damage to the bolt or hoop due to excessive torque, or a loose connection due to insufficient torque.

[0070] The above preset standard torque is a torque value set in advance before the bolt is fastened. This value can be determined according to the design requirements of the hoop, material properties, and use environment, and is a key parameter for ensuring the connection quality of the hoop. When the tightening torque of the bolt reaches the preset standard torque, it can be considered that the fastening degree of the bolt meets the requirements. As an example, the target torque can be 10 Nm.

[0071] In an embodiment, since each bolt corresponds to a motor, the torque output by the motor can be adjusted by adjusting the current and speed of the motor, so that the tightening torque of each bolt reaches the preset standard torque. For example, the motor can detect the tightening torque output by itself, and when the tightening torque is less than the preset standard torque, the output current is increased to increase the tightening torque to the preset standard torque.

[0072] In the transmission chain between the motor and the bolt, a torque sensor can be connected in series to detect the output tightening torque. Alternatively, the tightening torque can be calculated indirectly by the current. For example, it can be calculated by T = Kt*Iq. Where Kt is the torque constant of the motor, Iq is the q-axis current of the motor, and T is the equivalent torque.

[0073] It should be noted that in the vector control of the motor, in order to achieve accurate control of the motor torque and magnetic flux, the stator current is usually decomposed into two components, namely the d-axis current and the q-axis current. The d-axis current is used to generate the magnetic field of the motor and control the size of the magnetic flux of the motor. The q-axis current is directly related to the torque of the motor. Generally, the size of the q-axis current directly determines the size of the output torque of the motor.

[0074] It should be noted that the q-axis is not a physical output shaft of the motor (such as the rotor shaft), but a virtual coordinate axis constructed by mathematical model for precise control of motor torque and magnetic field. Based on the way of constructing the virtual coordinate axis, the complex three-phase current control logic can be effectively simplified, and the theoretical basis for motor torque regulation is provided.

[0075] In the bolt fastening process, the torque output by the motor is ultimately converted into the tightening torque of the bolt. Therefore, by collecting the q-axis current, the size of the motor output torque can be indirectly and accurately reflected, thereby providing a basis for subsequent current-based torque control and dynamic adjustment.

[0076] It should be noted that although T is not the actual torque acting on the bolt directly measured by the torque sensor, but an equivalent torque derived from the characteristics of the motor and the relationship between current and torque. However, the above equivalent torque can be considered as a tightening torque that indirectly reflects the size of the motor output torque to reflect the torque ultimately acting on the bolt by the motor.

[0077] In another embodiment, the hoop fastening device can first control multiple motors to synchronously fasten corresponding bolts at a preset rotation speed until the tightening torque of each bolt reaches a preset initial tightening torque. Wherein, the initial tightening torque is less than the preset standard torque. Then, control multiple motors to increase the tightening torque of each bolt from the initial tightening torque at the same torque growth rate until the tightening torque reaches the preset standard torque.

[0078] In an embodiment, the above-mentioned preset rotation speed refers to the pre-set motor rotation speed in the initial stage of controlling multiple motors to synchronously fasten corresponding bolts. Wherein, the above-mentioned preset rotation speed can be determined according to factors such as the material of the hoop, the specification of the bolt, and the fastening process requirements. It can be understood that selecting an appropriate preset rotation speed can ensure the fastening effect while avoiding damage to the bolt or hoop due to excessive impact caused by too high rotation speed, or affecting the fastening efficiency due to too low rotation speed. Exemplarily, the above-mentioned preset rotation speed can be 10 rpm.

[0079] The above-mentioned synchronous fastening refers to the operation of multiple motors driving corresponding bolts to rotate and fasten at the same preset rotation speed according to the same control instruction. The purpose of synchronous fastening is to enable multiple bolts to be tightened at the same speed and rhythm in the initial stage, and to try to ensure that each bolt is uniformly stressed, thereby laying a foundation for the subsequent torque growth process.

[0080] The above-mentioned initial tightening torque is an intermediate torque value pre-set in the bolt fastening process. The initial tightening torque needs to be less than the final preset standard torque, and is a transition torque value during the process of the bolt from the beginning of fastening to reaching the preset standard torque. The purpose of setting the initial tightening torque is to form a certain pre-tightening force between the hoop and the bolt in the initial fastening stage of the bolt, to ensure that the hoop mounting surface is initially fitted, and to establish an initial balanced plane for subsequent fastening.

[0081] The same torque growth rate refers to the same speed of increasing the tightening torque of the plurality of bolts by the plurality of motors during the process of increasing the initial tightening torque to the preset standard torque. The torque growth rate can be expressed by the amount of torque increase per unit time (for example, Nm / s). It should be noted that maintaining the same torque growth rate can ensure that the force on each bolt remains relatively uniform during the process of increasing the torque, avoiding problems such as hoop installation surface parallelism out of tolerance caused by the fact that some bolts increase the torque too fast or too slow. For example, the torque growth rate can be 2 Nm / s.

[0082] Based on the above description, it can be understood that when the torque has not reached the preset standard torque, the motor can be controlled to adjust the tightening torque by changing the size of the current until the preset standard torque is reached. For example, the hoop fastening device can control the plurality of motors to output currents corresponding to the preset rotation speed respectively, so that the plurality of motors fasten the corresponding bolts at the preset rotation speed respectively and synchronously, until the tightening torque of each bolt reaches the preset initial tightening torque. In addition, the hoop fastening device can control the plurality of motors to increase the current at the same current growth rate respectively, so that the plurality of motors increase the tightening torque of the corresponding bolts at the same torque growth rate from the initial tightening torque, until the tightening torque reaches the preset standard torque.

[0083] In another embodiment, the rotation speed of the motor can also be related to the magnetic flux size of the motor excitation winding, the pulse frequency of the motor driver, and other factors. Therefore, the rotation speed of the motor can also be controlled by adjusting other factors of the motor. In addition, the torque output by the motor is also related to the power of the motor, the efficiency of the transmission mechanism, and other factors. Therefore, the torque growth rate of the motor output can also be controlled by adjusting other factors of the motor. In this embodiment, the way of controlling the plurality of motors to work at the preset rotation speed and controlling the plurality of motors to work at the same torque growth rate is not limited.

[0084] In the embodiment, the plurality of motors are controlled to synchronously fasten the corresponding bolts at a preset rotating speed until the tightening torque of each bolt reaches a preset initial tightening torque, which can ensure that all the bolts approach the hoop contact surface at a consistent pace in the initial fastening stage, so that each bolt first reaches a uniform initial stress state (i.e., the initial tightening torque). Then, on the basis of the initial tightening torque, the plurality of motors are controlled to synchronously increase the torque at the same rate, which can realize the progressive and balanced increase of the bolt stress. Since the torque change pace of each motor is consistent, the stress increment of each bolt at each moment during the process from the initial state to the final standard torque is the same, which avoids the local stress concentration caused by the sudden increase of the torque of a certain bolt. Furthermore, the mounting surface of the hoop can always maintain uniform stress during the torque increase, which effectively reduces the risk of parallelism tolerance deviation caused by over-tightening or over-loosening of individual bolts.

[0085] S102, detecting the parallelism of the mounting surface of the hoop.

[0086] In an embodiment, the mounting surface refers to the inner surface of the hoop in contact with the fixed object, or the contact surface (such as the connecting flange surface of the flange hoop) when the two half rings of the hoop are spliced. The flatness and fitting accuracy of the mounting surface directly affect the tightening effect of the hoop. It can be understood that if the mounting surface is not flat or poorly fitted, it may lead to uneven stress, loose fixation, or even deformation of the fixed object.

[0087] The parallelism is one of the form and position tolerances, which refers to the state of maintaining equal distance between two planes (or lines, surfaces). For the mounting surface of the hoop, the parallelism usually refers to the parallelism between the inner mounting surfaces (the surfaces in contact with the fixed object) of the two half rings of the hoop, or the parallelism between the flange contact surfaces of the two half rings when the hoop is spliced. The smaller the parallelism error is, the more uniform the fitting of the mounting surface is, and the more stable the tightening force transmission is.

[0088] In an embodiment, the hoop fastening device can use a steel ruler (or a knife-edge ruler) with high flatness to be in contact with different positions of the mounting surface (for example, 3-4 measuring points are uniformly selected along the circumferential direction), and the gap between the steel ruler and the mounting surface is observed to obtain the parallelism.

[0089] In another embodiment, the hoop fastening device can also be installed with a plurality of laser ranging devices, which perform high-speed scanning on the mounting surface of the hoop by emitting laser beams, and collect three-dimensional coordinate data (point cloud) of the surface. For example, the point cloud density is > 20 points / cm 2That is, at least 20 points per square centimeter are collected to ensure that the surface details are captured completely (such as small concave-convex, deformation). Then, based on the point cloud data, an ideal plane of the mounting surface (i.e., a preset reference plane) is fitted by an algorithm, and the vertical distance between all scanned point clouds and the ideal plane is calculated. At this time, the hoop fastening device can determine the vertical distance corresponding to each scanning point as the parallelism, or the maximum value of each vertical distance can be determined as the parallelism, and the parallelism is not limited.

[0090] It should be noted that the parallelism is detected by the non-contact laser ranging device, which can avoid damaging the precise surface without contacting the mounting surface of the hoop. In addition, the ranging accuracy of the laser ranging device is high, and therefore the effect of bolt fastening can be accurately quantified.

[0091] In another embodiment, after obtaining the parallelism corresponding to each point cloud, a deformation field of the mounting surface can also be generated to intuitively show the deformation distribution of the mounting surface and provide a basis for subsequent angle adjustment and the like.

[0092] S103, if the parallelism is greater than or equal to the preset parallelism, the interval distance between each bolt and the preset reference plane is obtained.

[0093] In an embodiment, the preset parallelism refers to a preset maximum parallelism. For example, 2.5 mm. If the actual measured parallelism is greater than or equal to the preset parallelism, it can be considered that the fitting accuracy of the mounting surface of the hoop does not meet the requirements and needs to be adjusted.

[0094] The preset reference plane can be considered as a reference plane with known accuracy for measuring the relative position of the bolt and the mounting surface. For example, the preset reference plane can include a design reference plane of the hoop, a mounting platform plane obtained by fitting, and the like.

[0095] The interval distance can be considered as the vertical distance between the bolt head (or nut) and the preset reference plane. The distance reflects the height position of the bolt on the mounting surface. It can be understood that if the interval distance of a certain bolt is too large, it can be considered that the mounting position is too high (or the hoop is deformed at this position), or the bolt is too tight. That is, the mounting surface at the position of the bolt is deformed and needs to be adjusted.

[0096] In an embodiment, the interval distance can be measured by the laser ranging device in the above example, or the image of the bolt and the reference plane can be captured by an industrial camera, and the interval distance can be calculated by combining an image processing algorithm (i.e., a visual detection algorithm). In this embodiment, the way of obtaining the interval distance between each bolt and the preset reference plane is not limited.

[0097] It should be noted that when the parallelism is less than the preset parallelism, it can be considered that the effect of the bolt fastening meets the installation requirements. Further, the hoop installation can be ended.

[0098] S104, determine the first bolt corresponding to the maximum value of the interval distance, the first motor corresponding to the first bolt, the second bolt opposite to the first bolt, and the second motor corresponding to the second bolt.

[0099] In an embodiment, the bolt corresponding to the maximum value of the interval distance is the first bolt. Generally, the position of the first bolt can be one of the main factors causing the parallelism of the hoop installation surface to be out of tolerance. It can be understood that due to the large distance between the first bolt and the preset reference surface, the stress or position of the hoop at this position can be abnormal.

[0100] In the hoop fastening device, each bolt is driven to rotate by a corresponding motor, thereby realizing tightening or loosening operation. Therefore, after determining the first bolt, the motor connected to the first bolt and responsible for providing power for fastening or adjustment is the first motor.

[0101] In an embodiment, the bolts are generally symmetrically distributed in the structure of the hoop. After determining the position of the first bolt on the hoop, the second bolt opposite to the first bolt can be determined. It should be noted that selecting the opposite bolt for cooperative adjustment can more effectively change the stress state and position of the hoop during subsequent adjustment, thereby correcting the parallelism deviation of the installation surface. Through symmetric adjustment, the influence on the torque balance of other bolts can be reduced to a certain extent, thereby ensuring the overall torque stability.

[0102] The determination of the second motor is the same as the determination of the first motor, and will not be described in detail.

[0103] S105, determine the deflection angle according to the deviation between the interval distance corresponding to the first bolt and the interval distance corresponding to the second bolt.

[0104] In an embodiment, the hoop fastening device can be preconfigured with a mapping relationship between the deviation and the angle, so as to determine the deviation angle corresponding to the deviation based on the mapping relationship. In another embodiment, the product of the preset coefficient and the deviation can be determined as the above-mentioned deflection angle. For example, the above-mentioned preset coefficient can be 0.5. In this embodiment, the way of determining the deflection angle is not limited.

[0105] It should be noted that the deviation of the interval distance directly reflects the degree of tilting of the hoop. If the interval distance corresponding to the first bolt on one side is too large and the interval distance corresponding to the second bolt on the opposite side is too small, the hoop will be tilted, resulting in parallelism out of tolerance. At this time, the deflection angle can quantify the degree of tilting and be used for subsequent guided adjustment of the first bolt and the second bolt, so as to reduce the deviation of the interval distance of the two-side bolts and correct the parallelism.

[0106] S106, control the first motor to loosen the first bolt by a deflection angle, and control the second motor to tighten the second bolt by the deflection angle.

[0107] In an embodiment, the deflection angle of the bolt is the mechanical action amount finally required to be achieved, but the rotation angle of the motor needs to consider the influence of the speed reduction mechanism (such as reducer, gear box). Therefore, the hoop fastening device can determine the target rotation angle corresponding to the deflection angle based on the mapping relationship between the pre-set rotation angle and the bolt deflection angle. Further, control the first motor to loosen (reverse rotation) the first bolt by the target rotation angle. And, control the second motor to continue to tighten the second bolt by the target rotation angle.

[0108] In the embodiment, the hoop fastening device can first control multiple motors to respectively fasten corresponding bolts until the tightening torque of each bolt reaches a preset standard torque, thereby ensuring the consistency of the tightening torque of each bolt, avoiding the uneven torque that may occur during manual fastening or simple automatic fastening, laying a foundation for subsequent parallelism detection and adjustment, and helping to improve the overall connection reliability of the hoop. Then, the parallelism of the hoop mounting surface can be detected, and when the parallelism is greater than or equal to a preset parallelism, the spacing distance between multiple bolts and a preset reference surface is measured to determine a first bolt corresponding to the maximum spacing distance, a first motor corresponding to the first bolt, a second bolt opposite the first bolt, and a second motor corresponding to the second bolt. The parallelism is usually used to measure the mounting quality of the hoop. If the parallelism is not up to standard, it may affect the contact effect between the hoop and the connecting piece, increase the contact resistance, and cause unstable operation of the equipment. Based on this, when it is determined that the parallelism is not up to standard, the key bolts causing the parallelism to be out of tolerance, i.e., the first bolt with the maximum spacing distance and the second bolt opposite the first bolt, can be accurately determined by measuring the spacing distance between the bolts and the preset reference surface, so that the subsequent adjustment is more targeted, improving the efficiency and accuracy of the adjustment. Moreover, the opposite adjustment method can minimize the impact on the torque balance of other bolts during the adjustment process, ensuring the overall torque stability. Finally, the deflection angle is calculated based on the deviation of the spacing distance between the first bolt and the second bolt, and the first motor is controlled to loosen the first bolt by the deflection angle, and the second motor is controlled to tighten the second bolt by the deflection angle. The adjustment amount (deflection angle) can be accurately quantified based on the actual deviation, making the adjustment operation more accurate. Moreover, by loosening the first bolt that is too tight and tightening the second bolt that is too loose, the stress state of the hoop can be changed, thereby effectively correcting the parallelism deviation of the mounting surface and improving the accuracy and effectiveness of the adjustment. Based on this, the above-mentioned cooperative adjustment method can quickly and accurately solve the parallelism problem while ensuring that the torque of other bolts remains basically unchanged, improving the efficiency and reliability of the adjustment, and avoiding unnecessary trouble and risks caused by re-tightening all bolts or random adjustment.

[0109] In another embodiment, during the process of controlling multiple motors to respectively fasten corresponding bolts until the tightening torque of each bolt reaches a preset standard torque, even if the same control parameters (such as rotation speed, torque growth rate) are preset, the tightening torque output by each motor may still deviate in actual operation due to the following factors:

[0110] Motor individual difference: the torque constant, internal resistance and response speed of different motors may have slight differences, and the output torque is inconsistent under the same current. Mechanical transmission error: the transmission chain (reducer, coupling, sleeve) of each bolt has differences in friction coefficient and transmission efficiency, resulting in different transmission efficiency of the motor output torque to the bolt. Load fluctuation: the thread accuracy, lubrication state and surface roughness of the bolt and nut are different, resulting in different tightening resistance of each bolt, and the motor needs to output different torque to maintain the synchronous speed.

[0111] Based on the above factors, the output current of part of the motors will be too large (corresponding to high torque), and the output current of another part of the motors will be too small (corresponding to low torque), which will eventually lead to unbalanced tightening torque of each bolt.

[0112] It should be noted that if the tightening torque of each bolt is unbalanced during the tightening process, the bolt with a high tightening torque may have been subjected to excessive stress before reaching the initial tightening torque or the preset standard torque, resulting in the actual tightening torque exceeding the preset standard torque. The bolt with a lower tightening torque may not reach the initial tightening torque or the preset standard torque within the specified time, resulting in inconsistent torque of each bolt. Moreover, during the tightening process, if the unbalanced tightening torque leads to a difference in the tightening speed of each bolt, the pre-tightening force of the bolt may be unevenly distributed, causing uneven stress on the clamp, thereby affecting the reliability and stability of the clamp fastening. That is, the parallelism of the installation surface after the execution of S101 step may be large.

[0113] Therefore, in order to improve the fastening effect during the clamp fastening process, the clamp fastening device can also fasten the bolts according to the S201-S204 steps as shown in Figure 2 The details are as follows:

[0114] S201, during the process of controlling multiple motors to tighten corresponding bolts respectively, the currents output by the multiple motors are collected respectively.

[0115] In an embodiment, the above-mentioned current can be considered as the q-axis current in the S101 example.

[0116] The clamp fastening device can detect the above-mentioned current according to the current detection element related to the motor. For example, a current sensor such as a Hall current sensor is installed in the stator winding of the motor to detect the current in the stator winding in real time.

[0117] S202, based on the multiple currents, determining a third motor and a fourth motor whose tightening torques output by the multiple motors respectively have deviations.

[0118] In an embodiment, the third motor and the fourth motor are two motors determined to have a deviation in tightening torque among the plurality of motors, and the third motor corresponds to a current (first current) greater than a current (second current) corresponding to the fourth motor.

[0119] In an embodiment, based on the above explanation of the tightening torque and the current, the hoop fastening device can determine the two motors corresponding to the current difference greater than the preset difference as the third motor and the fourth motor having a deviation in tightening torque. In addition, when there are a plurality of current differences greater than the preset difference, the two motors corresponding to the maximum current difference among the plurality of current differences can be determined as the third motor and the fourth motor having a deviation in tightening torque. The deviation value can be set according to actual needs, which is not limited.

[0120] In another embodiment, the hoop fastening device can further calculate the actual torque output by each motor based on the plurality of currents. Then, the third motor and the fourth motor are determined based on the plurality of actual torques. The way of determining the third motor and the fourth motor based on the plurality of actual torques can refer to the above example, which will not be described in detail.

[0121] As an example, the hoop fastening device can first calculate the current difference between each two currents among the plurality of currents. Then, the ratio between the maximum current difference among the plurality of current differences and the average value of the plurality of current differences is calculated, and when the ratio is greater than a preset ratio, the two motors corresponding to the maximum current difference are determined as the third motor and the fourth motor. Otherwise, when the ratio is less than or equal to the preset ratio, it can be considered that the maximum current difference is small, and the difference between the tightening torques output by the two motors corresponding to the maximum current difference is small, so there is no need to adjust the current additionally.

[0122] The preset ratio can be set according to actual needs, which is not limited. For example, the preset ratio can be 0.5%.

[0123] It should be noted that when calculating the maximum current difference and the average value of the current difference, the absolute value of each current difference is usually taken to eliminate the influence of direction and only focus on the size of the current difference.

[0124] For example, the clamp fastening device can subtract the current value of each motor from the current values of all other motors to obtain the current difference between each pair of motors. For example, if the current values of motor 1, motor 2, motor 3, and motor 4 are I1, I2, I3, and I4, respectively, the current differences I1-I2, I1-I3, I1-I4, I2-I3, I2-I4, and I3-I4 can be calculated. Each of the current differences can be described in absolute value. Then, if the current difference I1-I4 is the largest (i.e., the largest current difference), the ratio of the largest current difference I1-I4 to the average of all current values can be calculated. When the ratio is greater than a preset ratio (1) and I4 is greater than I1, the motor outputting the current I4 is considered to be the third motor, and the motor outputting the current I1 is considered to be the fourth motor.

[0125] In another embodiment, when determining the largest current difference, the difference between the largest current and the smallest current can be directly determined as the largest current difference. However, since the average of multiple current differences needs to be calculated, the largest current difference can be determined after the current differences between each pair of currents are calculated.

[0126] In this embodiment, by calculating the current difference between any two currents, the clamp fastening device can comprehensively capture the differences in the output torques of the motors and avoid missing local deviations. Then, the largest current difference (reflecting the most significant torque deviation) can be extracted from all current differences, and the average of all current differences (reflecting the overall average deviation level) can be calculated to quantify the relative relationship between the local extreme deviation and the overall average deviation through the ratio of the largest current difference to the average. Finally, when the ratio is greater than a preset ratio, it can be considered that there is an extreme deviation far exceeding the overall average level, and at this time, the two motors corresponding to the largest current difference are determined as the third motor and the fourth motor that need to be adjusted, which not only improves the flexibility and accuracy of the judgment, avoids false positives or false negatives caused by a fixed threshold, but also avoids adjusting all motors without distinction, realizes targeted adjustment, and ensures the efficiency and effectiveness of the adjustment.

[0127] S203, reducing the first current output by the third motor and increasing the second current output by the fourth motor.

[0128] S204, controlling the plurality of motors to fasten the corresponding bolts based on the adjusted currents, respectively, until the tightening torque of each bolt reaches a preset standard torque.

[0129] In an embodiment, the manner of reducing the first current can be to take the difference between the first current and a first preset current as the reduced first current, or to take the product of the first current and a first preset percentage (less than 1) as the reduced first current. For example, the product of the first current and 90% can be taken as the reduced first current.

[0130] In an embodiment, the manner of increasing the second current can be to take the sum of the second current and a second preset current as the increased second current, or to take the product of the second current and a second preset percentage (greater than 1) as the increased second current. For example, the product of the second current and 105% can be taken as the increased second current.

[0131] In the embodiment, the manner of reducing the first current and the manner of increasing the second current are not limited.

[0132] In an embodiment, the manner of controlling the plurality of motors to fasten the corresponding bolts based on the adjusted currents can be to control the third motor to fasten the bolts based on the reduced first current, to control the fourth motor to fasten the bolts based on the increased second current, and to control the remaining motors to maintain the currents output by the motors unchanged to fasten the bolts.

[0133] It should be noted that when the tightening torque of each bolt does not reach the preset standard torque, the hoop fastening device can execute the above steps S201-S204 once every preset interval time length, so that the tightening torque of each bolt can be maintained balanced when the bolts are fastened. For example, the above process can be executed every 0.5s.

[0134] In this embodiment, in the process of controlling multiple motors to respectively tighten corresponding bolts, the current value output by each motor is collected in real time, which can provide data support for subsequent judgment of whether the torque output by each motor is deviated. Then, based on the collected multiple current values, the difference between each two currents is calculated to determine the third motor and the fourth motor whose tightening torque is deviated, where the current corresponding to the third motor (the first current) is greater than the current corresponding to the fourth motor (the second current), which can accurately identify the motor whose output torque is deviated, provide a clear target for subsequent adjustment operation, avoid blind adjustment of all motors, and improve the pertinence and efficiency of adjustment. Finally, for the determined third motor and fourth motor, measures can be taken to reduce the first current output by the third motor and increase the second current output by the fourth motor, and control multiple motors to tighten corresponding bolts based on the adjusted current until the tightening torque of each bolt reaches the preset standard torque. Based on this, by reducing the current of the third motor to reduce its output torque, it can avoid that the tightening torque of the bolt corresponding to the motor is too large, and by increasing the current of the fourth motor to increase its output torque, it can increase the tightening torque of the bolt corresponding to the motor. Further, through the above adjustment, the tightening torque of each bolt during the tightening process can gradually tend to be balanced. That is, it ensures that the force of each bolt is balanced in real time, and avoids the clamping hoop from being skewed due to uneven force.

[0135] In another embodiment, due to the influence of factors such as individual differences of motors, mechanical transmission errors, and load fluctuations (thread jamming during bolt tightening), the motor output current may be abnormal. If the abnormal current is not handled in time, it may cause problems such as motor overload, insufficient or unstable output torque, thereby affecting the tightening effect of the bolt.

[0136] Based on this, in order to ensure the tightening effect of the bolt, after performing the above S201 step, if there is a current that does not meet the preset current constraint condition, the clamping hoop tightening device can control multiple motors to perform a target fault response action corresponding to the current constraint condition. Otherwise, when it is determined that the multiple currents all meet the current constraint condition, the third motor and the fourth motor whose tightening torque output by the multiple motors is deviated are determined based on the multiple currents in the above S202 step.

[0137] Wherein, the current constraint condition can be 1 or multiple, which is not limited. Wherein, the fault response action can correspond to the current constraint condition, for example, one fault response action can correspond to one or more current constraint conditions. At this time, the target fault response action is the fault response action corresponding to the current constraint condition that the current meets at this time.

[0138] As an example, the current constraint condition can include that the current change rate is greater than a preset change rate (e.g., the current change rate is greater than 2 A / s), the current is greater than a first preset multiple of the rated current and less than or equal to a second preset multiple of the rated current, and the current is greater than the second preset multiple of the rated current. As an example, the first preset multiple can be 1.1, and the second preset multiple can be 1.3.

[0139] Corresponding to the above current constraint condition, when the current change rate is greater than the preset change rate, the fault response action (corresponding to the gradual jamming of the bolt) can be that within 100 ms, the current corresponding to the current change rate greater than the preset change rate is reduced (e.g., the current is reduced by 50%), and an audible and visual alarm is performed; when the current is greater than the first preset multiple of the rated current and less than or equal to the second preset multiple of the rated current, the fault response action (corresponding to the sudden jamming of the bolt) can be that within 50 ms, the motor corresponding to the current is controlled to loosen the bolt by a preset angle (e.g., the motor is controlled to reverse the bolt by an angle corresponding to 0.5 turns), and an audible and visual alarm is performed; and when the current is greater than the second preset multiple of the rated current, the fault response action (corresponding to the mechanical thinking of the bolt) can be that within 20 ms, the total power supply is controlled to be turned off, the bolt is stopped, and an audible and visual alarm is performed.

[0140] In the above examples, different current constraint conditions correspond to different levels of fault types, and therefore the corresponding fault response actions are also different. Based on this, for different fault types (gradual jamming, sudden jamming, and mechanical jamming), different current constraint conditions and corresponding fault response actions are set, which can take appropriate measures according to the severity of the fault through a hierarchical processing manner, avoid overreaction or insufficient reaction, and effectively protect the safety of the clamp fastening protection device and the operator.

[0141] In another embodiment, the above current constraint condition can be multiple, and the fault response action can be only one. For example, the fault response action can be that within 20 ms, the total power supply is controlled to be turned off, the bolt is stopped, and an audible and visual alarm is performed, so as to maximize the safety during the fastening process.

[0142] In this embodiment, the current of each motor is monitored in real time, and when the current of any one or more motors does not meet the preset current constraint condition, the corresponding target fault response action is immediately controlled to be performed by the plurality of motors, which can take measures at the first time when the motor current is abnormal, and avoid further damage to the motor and the entire bolt fastening caused by the current abnormality. In addition, if the plurality of currents all meet the current constraint condition, it can be considered that the motor is running normally. Therefore, the above S202 step and the subsequent steps of fastening the bolt can be performed.

[0143] In another embodiment, the process of detecting whether the current meets the preset current constraint condition can also be performed in step S106. That is, the process of detecting whether the current meets the preset current constraint condition can be applied to the entire process when the motor needs to output torque, to ensure the safety of the motor operation.

[0144] In an embodiment, based on the above embodiments, after performing the step of controlling multiple motors to respectively tighten corresponding bolts until the tightening torque of each bolt reaches the preset standard torque, the steps S102-S105 are used to detect the parallelism and determine the deflection angle when the parallelism is greater than or equal to the preset parallelism. In these steps, the motor does not need to output the tightening torque.

[0145] Based on this, after S101, the hoop tightening device can also maintain the tightening torque of each bolt at the preset standard torque for a preset time period. That is, during the preset time period, the motor can not need to operate, and the hoop tightening device can perform steps S102-S105.

[0146] The preset time period can be set according to actual needs, and is not limited. For example, the preset time period can be 2s.

[0147] It should be noted that maintaining the tightening torque of each bolt at the preset standard torque for a preset time period can effectively offset the initial creep effect between the bolt and the hoop. After the bolt is tightened, due to the plastic properties of the material itself and the micro-deformation of the hoop, a small creep may occur under stress. That is, the bolt will slowly relax due to continuous stress, and the contact part of the hoop may also deform slightly due to stress release, resulting in a slight decrease in the actual torque over time. By maintaining the preset standard torque for a preset time period, the initial creep can occur in a controlled state, avoiding unexpected torque decay due to unrelieved creep in subsequent use, thereby ensuring the stability of the torque in long-term use. Moreover, during the preset time period, when the parallelism is detected to be greater than or equal to the preset parallelism, the subsequent steps can be adjusted to further improve the effect of the hoop tightening.

[0148] Based on the explanation of the above embodiments, it can be considered that after performing the above S101-S106 once, the parallelism may still not meet the requirements. Based on this, in order to ensure that the parallelism of the installed hoop meets the requirements, the hoop tightening device can repeatedly perform the target step and each step after the target step until the parallelism is less than the preset parallelism. The target step is to control multiple motors to respectively tighten corresponding bolts until the tightening torque of each bolt reaches the preset standard torque. That is, it starts to perform from step S101 again.

[0149] In another embodiment, based on the explanation of S101, the fastening process includes: controlling the plurality of motors to synchronously fasten the corresponding bolts at a preset rotation speed, until the tightening torque of each bolt reaches a preset initial tightening torque, and controlling the plurality of motors to increase the tightening torque of each bolt from the initial tightening torque at a same torque increasing rate, until the tightening torque reaches a preset standard torque. In this embodiment, since the tightening torque of each bolt after the execution of S101-S106 is usually close to the preset standard torque. Therefore, in the repeated execution process, the execution of the step of controlling the plurality of motors to increase the tightening torque of each bolt from the initial tightening torque at a same torque increasing rate, until the tightening torque reaches a preset standard torque in S101 is not limited.

[0150] It should be noted that even if the tightening torque of each bolt is close to the preset standard torque in the repeated execution of the above steps, the repeated execution of the fastening process can further adjust the unevenly stressed bolts. Further, the stress of each bolt can be more uniform to reduce the parallelism of the hoop mounting surface.

[0151] It should be noted that the parallelism of the mounting surface is usually a geometric precision index, which can reflect the fit degree of the hoop mounting surface and the connecting member surface (such as the uniformity of the plane gap), and the core is to ensure the stability of the mechanical structure, and avoid local stress concentration, component deformation or mechanical wear caused by the inclination of the mounting surface. However, the parallelism less than the preset parallelism can only indicate that the hoop mounting surface is aligned with the connecting member surface, and cannot ensure the microscopic close contact between the contact surfaces. That is, even if the macroscopic parallelism, the contact surface may still have insufficient actual contact area due to the presence of oil stains, oxide layers, small protrusions or depressions. Further, the contact between the hoop and the connecting member affects the conductive effect.

[0152] Therefore, in order to further improve the conductive effect of the hoop and the connecting member, the hoop fastening device can also fasten the bolts according to S301-S303 steps as shown in Figure 3 The details are as follows:

[0153] S301, detecting the contact resistance between the hoop and the connecting member.

[0154] In an embodiment, the above connecting member includes but is not limited to a conductor, a pipeline, a rod (for example, a conductive rod), and the like, which is not limited. For ease of explanation, the above connecting member can be a conductive rod.

[0155] The above contact resistance refers to the resistance generated when the current passes through the contact surface of two conductors (such as the hoop and the connecting member), and is a core index for measuring the electrical connection quality between the conductors.

[0156] It should be noted that from a microscopic point of view, even if two conductor surfaces are macroscopically adhered, actual contact only occurs at a few protruding "contact points" (due to surface roughness, oxide layer, contaminants, etc.). When the current passes through these limited contact points, it will generate additional resistance due to the reduction of the conduction area and the concentration of the current path, i.e. contact resistance. Its size is closely related to the contact surface pressure, cleanliness, material properties, surface treatment process, etc. Generally, the greater the contact surface pressure, the higher the cleanliness, the better the metal conductivity, the smaller the contact resistance; if there is an oxide film, oil stain, rust, etc., it will significantly increase the contact resistance.

[0157] In an embodiment, the detection of the above-mentioned contact resistance can be achieved by measuring the voltage drop when the current passes through the contact surface through a special instrument or method, and then calculating the resistance value by Ohm's law. Common detection methods can include: direct current voltage drop method, four-wire method to measure voltage drop, micro-ohmmeter measurement method, which will not be described in detail.

[0158] S302, if the contact resistance is greater than the preset resistance, an ultrasonic vibration signal is sent to the contact surface between the clamp and the connecting piece.

[0159] In an embodiment, the above-mentioned preset resistance is a contact resistance threshold value preset according to the conduction requirements, safety standards or design requirements of the equipment. When the actual contact resistance exceeds this value, measures need to be taken to optimize the connection quality. Exemplarily, the above-mentioned preset resistance can be 5Ω.

[0160] Among them, the above-mentioned ultrasonic vibration signal is a mechanical vibration signal with a frequency higher than 20kHz (which cannot be heard by human ears), which is converted into a high-frequency mechanical vibration by an ultrasonic generator and acts on the contact surface to remove impurities and improve the adhesion state. Based on this, the clamp fastening device can be connected with an ultrasonic activation system to generate and send ultrasonic vibration signals.

[0161] Among them, the ultrasonic activation system can include an ultrasonic generator, a transducer (vibrator) and an amplitude transformer. The ultrasonic generator can convert electrical energy into high-frequency (for example, 20kHz) electrical signals (ultrasonic vibration signals) to drive the transducer to vibrate; the transducer can convert electrical signals into mechanical vibrations (for example, amplitude 3μm) by using piezoelectric effect, which is the core component of energy conversion. The amplitude transformer can amplify the vibration amplitude and transmit it to the surface of the clamp, so that the vibration energy acts on the contact surface.

[0162] Among them, the amplitude of ultrasonic vibration directly affects the shear stress (lateral force generated by vibration) of the contact surface. By controlling the amplitude to be 3μm, the shear stress between the micro protrusions of the contact surface can exceed the yield strength of copper (33MPa), thereby breaking the oxide layer and promoting close contact between metals.

[0163] In addition, during the process of sending the ultrasonic vibration signal, the servo system can also be used to fine-tune and compensate the pressure fluctuation (for example, ±0.1 Nm). It should be noted that the pressing force of the clamp and the connecting piece is controlled by the servo system, and when the pressure fluctuation exceeds ±0.1 Nm, the motor can adjust the pressing force in real time to ensure the stability of the contact surface pressure and avoid the fluctuation of the contact resistance caused by the change of the pressure.

[0164] In another embodiment, when the contact resistance is less than or equal to the preset resistance, it can be considered that the electrical connection quality of the contact surface between the clamp and the connecting piece meets the requirements, and no further processing is required. Further, the clamp fastening process can be ended.

[0165] S303, after stopping sending the ultrasonic vibration signal, repeatedly performing the target step and each step after the target step until the contact resistance is less than or equal to the preset resistance.

[0166] In an embodiment, the condition for stopping sending the ultrasonic vibration signal can be that the duration of sending the ultrasonic vibration signal reaches a preset duration (for example, 20s), or the temperature of the contact surface is greater than or equal to a preset temperature (for example, 80℃), the sending of the ultrasonic vibration signal is stopped.

[0167] It should be noted that the duration of sending the ultrasonic vibration signal is 20 seconds, which can balance the needs of removing impurities and avoiding overheating (long-time vibration may cause the temperature of the contact surface to exceed the limit). In addition, the contact surface of the clamp and the connecting piece will generate Joule heat when the current passes through due to the existence of the contact resistance. If the temperature of the contact surface rises, it may cause the oxide layer of the contact surface to generate faster (high temperature promotes the oxidation of metal), further increasing the contact resistance; and the uneven thermal expansion of the material causes the change of the pressure distribution of the contact surface, affecting the stability of the connection.

[0168] It should be noted that during the process of sending the ultrasonic vibration signal, the high-frequency vibration may have a certain impact on the tightening torque of the bolt. On the one hand, the vibration may change the friction between the bolt and the connected component, thereby causing the loss of the tightening torque; on the other hand, the vibration may change the pre-tightening force distribution of the bolt, affecting the tightening quality of the bolt.

[0169] Based on this, after stopping sending the ultrasonic vibration signal, in order to ensure the fastening effect of the clamp, it is necessary to start from step S101 again until the contact resistance is less than the preset resistance. At this time, after ending the entire clamp fastening process, not only the parallelism of the clamp mounting surface is less than the preset parallelism, but also the contact resistance between the clamp and the connecting piece will be less than or equal to the preset resistance.

[0170] In the embodiment, the contact resistance is a key indicator for measuring the quality of the electrical connection between the hoop and the connecting piece. By detecting the contact resistance, problems existing in the electrical connection can be found in time, providing a basis for subsequent processing. Then, the detected contact resistance is compared with the preset resistance to determine whether the current contact resistance meets the requirements. That is, when the contact resistance is greater than the preset resistance, it indicates that the quality of the electrical connection does not meet the requirements. At this time, the hoop fastening device can send an ultrasonic vibration signal to the contact surface between the hoop and the connecting piece to effectively remove impurities such as oxidation layer, oil stains, dust, etc. on the contact surface, improve the microstructure of the contact surface, and promote the close contact between metals. Finally, after stopping sending the ultrasonic vibration signal, the target steps of controlling multiple motors to respectively tighten corresponding bolts until the tightening torque of each bolt reaches the preset standard torque, and the subsequent steps are repeated until the contact resistance is less than or equal to the preset resistance. The tightening torque of the bolt can be re-adjusted to compensate for the torque loss caused by the ultrasonic vibration signal, ensuring that the tightening torque, parallelism and contact resistance of the bolt still meet the preset standards, and ensuring the reliability and stability of the bolt connection. That is, it ensures that the mechanical connection and electrical connection between the hoop and the connecting piece meet the requirements, and improves the fastening effect of the hoop.

[0171] In order to more clearly illustrate the scheme in the present application, the following uses specific embodiments to explain the scheme in the present application. For details, please refer to Figure 4 , Figure 4 is an implementation schematic diagram of a bolt fastening method provided by another embodiment of the present application.

[0172] The hoop fastening device can include a display touch device, and a user can set one or more information such as initial tightening torque, preset standard torque, preset parallelism, torque growth number, preset ratio, current constraint condition, preset time length, and preset resistance in the display touch device. In actual application, the hoop fastening device can control multiple motors to respectively and synchronously tighten corresponding bolts at a preset rotating speed until the tightening torque of each bolt reaches the preset initial tightening torque. And control multiple motors to increase the tightening torque of each bolt at the same torque growth rate from the initial tightening torque until the tightening torque reaches the preset standard torque.

[0173] In the process of fastening the bolt, the hoop fastening device can also respectively collect the currents output by the multiple motors, and based on the multiple currents, determine the third motor and the fourth motor whose tightening torques output by the multiple motors respectively exist deviations. Then, the first current output by the third motor is reduced, and the second current output by the fourth motor is increased to control the multiple motors to respectively tighten corresponding bolts based on the adjusted currents until the tightening torque of each bolt is the preset standard torque.

[0174] Afterwards, the hoop fastening device can maintain the tightening torque of each bolt as the preset standard torque within a preset time period. And, the parallelism of the installation surface of the hoop can also be detected within the preset time period, and when the parallelism is greater than or equal to the preset parallelism, the interval distance between each of the plurality of bolts and the preset reference surface is obtained. And, the first bolt corresponding to the maximum value of the interval distance, the first motor corresponding to the first bolt, the second bolt opposite to the first bolt, and the second motor corresponding to the second bolt are determined.

[0175] Then, the hoop fastening device can determine the deflection angle according to the deviation between the interval distance corresponding to the first bolt and the interval distance corresponding to the second bolt, to control the first motor to loosen the first bolt by the deflection angle, and control the second motor to tighten the second bolt by the deflection angle. And, the steps of controlling the plurality of motors to tighten the corresponding bolts respectively until the tightening torque of each bolt reaches the preset standard torque, and the subsequent steps are repeatedly executed until the parallelism is less than the preset parallelism.

[0176] Finally, when the parallelism is less than the preset parallelism, the hoop fastening device can detect the contact resistance between the hoop and the connecting piece. And, when the contact resistance is greater than the preset resistance, an ultrasonic vibration signal is sent to the contact surface between the hoop and the connecting piece, and after stopping sending the ultrasonic vibration signal, the steps of controlling the plurality of motors to tighten the corresponding bolts respectively until the tightening torque of each bolt reaches the preset standard torque, and the subsequent steps are repeatedly executed again until the contact resistance is less than or equal to the preset resistance.

[0177] Need to be explained, in the execution of the above-mentioned bolt fastening process, it is necessary to detect whether there is a current that does not meet the preset current constraint condition. And, when there is a current that does not meet the constraint condition, the plurality of motors perform the target fault response action corresponding to the current constraint condition to ensure the safety in the fastening process. And, when the plurality of currents all meet the current constraint condition, the subsequent steps are continued to be executed based on the plurality of currents. For example, the step of determining the third motor and the fourth motor whose tightening torque output by the plurality of motors respectively exists deviation based on the plurality of currents is executed.

[0178] In this embodiment, during the process of controlling multiple motors to tighten corresponding bolts, reducing the current of the third motor to decrease its output torque can prevent excessive tightening torque of the bolt corresponding to that motor. Simultaneously, increasing the current of the fourth motor to increase its output torque can increase the tightening torque of the bolt corresponding to that motor. Furthermore, through these adjustments, the tightening torque of each bolt gradually becomes more balanced during the tightening process. That is, it ensures that the force on each bolt is balanced in real time, avoiding clamp misalignment due to uneven force, which would cause the parallelism to be less than the preset parallelism. Moreover, after the parallelism becomes less than the preset parallelism, by sending an ultrasonic vibration signal when the contact resistance is greater than the preset resistance, and repeatedly executing the target step of controlling multiple motors to tighten corresponding bolts until the tightening torque of each bolt reaches the preset standard torque, and subsequent steps, until the contact resistance is less than or equal to the preset resistance, the tightening torque of the bolts can be readjusted to compensate for the torque loss caused by the ultrasonic vibration signal. This ensures that the tightening torque, parallelism, and contact resistance of the bolts still meet the preset standards, guaranteeing the reliability and stability of the bolt connection. That is, ensure that the mechanical and electrical connections between the clamp and the connector meet the requirements to improve the clamp's fastening effect.

[0179] Please see Figure 5 , Figure 5 This is a schematic diagram of a bolt fastening device according to an embodiment of this application. The bolt fastening device in this embodiment includes modules for performing... Figures 1 to 4 The steps in the corresponding embodiments. Please refer to the details. Figures 1 to 4 as well as Figures 1 to 4 The relevant descriptions in the corresponding embodiments are shown below. For ease of explanation, only the parts relevant to this embodiment are shown. The bolt fastening device can be applied to a clamp fastening device, which includes multiple motors, each motor outputting power to fasten the corresponding bolt in the clamp. See also... Figure 5 The bolt fastening device 500 may include: a first control module 510, a detection module 520, an acquisition module 530, a first determination module 540, a second determination module 550, and a second control module 560, wherein:

[0180] The first control module 510 is used to control multiple motors to tighten corresponding bolts until the tightening torque of each bolt reaches the preset standard torque.

[0181] The detection module 520 is used to detect the parallelism of the mounting surface of the clamp.

[0182] The acquisition module 530 is used to acquire the interval distance between multiple bolts and the preset reference surface if the parallelism is greater than or equal to the preset parallelism.

[0183] The first determining module 540 is configured to determine a first bolt corresponding to a maximum value of the interval distance, a first motor corresponding to the first bolt, a second bolt opposite to the first bolt, and a second motor corresponding to the second bolt.

[0184] The second determining module 550 is configured to determine the deflection angle according to a deviation between the interval distance corresponding to the first bolt and the interval distance corresponding to the second bolt.

[0185] The second control module 560 is configured to control the first motor to loosen the first bolt by the deflection angle, and control the second motor to tighten the second bolt by the deflection angle.

[0186] In an embodiment, the first control module 510 is further configured to:

[0187] control the plurality of motors to synchronously tighten the corresponding bolts at a preset rotating speed, until the tightening torque of each bolt reaches a preset initial tightening torque, wherein the initial tightening torque is less than a preset standard torque;

[0188] control the plurality of motors to increase the tightening torque of each bolt from the initial tightening torque at a same torque increasing rate, until the tightening torque reaches the preset standard torque.

[0189] In an embodiment, the first control module 510 is further configured to:

[0190] collect currents output by the plurality of motors during the process of controlling the plurality of motors to tighten the corresponding bolts, respectively;

[0191] determine a third motor and a fourth motor from the plurality of motors based on the plurality of currents, wherein the third motor and the fourth motor have a deviation in the tightening torque output by the third motor and the fourth motor, respectively, and a first current corresponding to the third motor is greater than a second current corresponding to the fourth motor;

[0192] reduce the first current output by the third motor, and increase the second current output by the fourth motor;

[0193] control the plurality of motors to tighten the corresponding bolts based on the adjusted currents, respectively, until the tightening torque of each bolt reaches the preset standard torque.

[0194] In an embodiment, the first control module 510 is further configured to:

[0195] calculate current differences between two currents from the plurality of currents;

[0196] calculate a ratio between a maximum current difference from the plurality of current differences and an average value of the plurality of current differences;

[0197] if the ratio is greater than a preset ratio, determine that two motors corresponding to the maximum current difference are the third motor and the fourth motor, respectively.

[0198] In an embodiment, the bolt fastening device 500 further comprises:

[0199] The third control module is configured to control the plurality of motors to perform a target fault response action corresponding to the current constraint condition if the current does not meet the preset current constraint condition.

[0200] The third determination module is configured to determine a third motor and a fourth motor whose tightening torques are deviated based on the plurality of currents if the plurality of currents all meet the current constraint condition.

[0201] In an embodiment, the bolt fastening device 500 further comprises:

[0202] The maintenance module is configured to maintain the tightening torque of each bolt as the preset standard torque within a preset time length.

[0203] In an embodiment, the bolt fastening device 500 further comprises:

[0204] The first execution module is configured to repeatedly perform the target step and each step after the target step until the parallelism is less than the preset parallelism, wherein the target step is to control the plurality of motors to tighten the corresponding bolts respectively until the tightening torque of each bolt reaches the preset standard torque.

[0205] In an embodiment, the bolt fastening device 500 further comprises:

[0206] The detection module is configured to detect the contact resistance between the hoop and the connecting piece.

[0207] The ultrasonic module is configured to send an ultrasonic vibration signal to the contact surface between the hoop and the connecting piece if the contact resistance is greater than the preset resistance.

[0208] The second execution module is configured to repeatedly perform the target step and each step after the target step until the contact resistance is less than or equal to the preset resistance after stopping sending the ultrasonic vibration signal.

[0209] It is understood that, Figure 5 The structure diagram of the bolt fastening device shown is used to perform Figures 1 to 4 each step in the corresponding embodiment, and for Figures 1 to 4 each step in the corresponding embodiment has been explained in detail in the above embodiments, please refer to Figures 1 to 4 and Figures 1 to 4 the related description in the corresponding embodiment, which will not be repeated here.

[0210] Figure 6 is a structure diagram of a hoop fastening device provided by an embodiment of the present application. As Figure 6As shown, the hoop fastening device 600 of the embodiment includes a processor 610, a memory 620, and a computer program 630 stored in the memory 620 and executable by the processor 610, such as a program of the bolt fastening method. The hoop fastening device includes a plurality of motors 640. The processor 610 implements the steps in each of the embodiments of the bolt fastening method described above when executing the computer program 630 to control the plurality of motors 640 to respectively output power for fastening corresponding bolts in the hoop. For example Figure 1 As shown, S101 to S104 are implemented. Alternatively, the processor 610 implements the steps in each of the embodiments of the bolt fastening method described above when executing the computer program 630. Figure 5 The functions of the modules in the corresponding embodiments, for example, Figure 5 The functions of the modules are shown in the above description of the corresponding embodiments, and details are described in the above description of the corresponding embodiments. Figure 5 The functions of the modules in the corresponding embodiments, for example,

[0211] For example, the computer program 630 can be divided into one or more modules, and the one or more modules are stored in the memory 620 and executed by the processor 610 to implement the bolt fastening method provided by the embodiments of the present application. The one or more modules can be a series of computer program instruction segments capable of completing a specific function, and the instruction segments are used to describe the execution process of the computer program 630 in the hoop fastening device 600. For example, the computer program 630 can implement the bolt fastening method provided by the embodiments of the present application.

[0212] The hoop fastening device 600 can include, but is not limited to, the processor 610 and the memory 620. Those skilled in the art can understand that Figure 6 The hoop fastening device 600 is only an example and does not constitute a limitation on the hoop fastening device 600, and can include more or fewer components than shown, or combine certain components, or different components, for example, the hoop fastening device can also include an input / output device, a network access device, a bus, etc.

[0213] The processor 610 can be a central processing unit, and can also be other general-purpose processors, digital signal processors, application-specific integrated circuits, ready programmable gate arrays or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc. The general-purpose processor can be a microprocessor or the processor can be any conventional processor.

[0214] The memory 620 can be an internal storage unit of the hoop fastening device 600, such as a hard disk or a memory of the hoop fastening device 600. The memory 620 can also be an external storage device of the hoop fastening device 600, such as a plug-in hard disk, a smart memory card, a flash memory card, etc. Further, the memory 620 can include both the internal storage unit and the external storage device of the hoop fastening device 600.

[0215] The embodiment of the present application provides a computer readable storage medium, comprising a memory, a processor and a computer program stored in the memory and executable on the processor, and the processor implements the bolt fastening method in each of the above embodiments when executing the computer program.

[0216] The embodiment of the present application provides a computer program product, which, when running on the hoop fastening device, enables the hoop fastening device to execute the bolt fastening method in each of the above embodiments.

[0217] The above embodiments are only used to illustrate the technical solutions of the present application, rather than limit them; although the foregoing embodiments of the present application are described in detail, those skilled in the art should understand: the technical solutions recorded in the foregoing embodiments can still be modified, or some technical features can be replaced by equivalents; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present application, and should be included in the protection scope of the present application.

Claims

1. A bolt fastening method, characterized in that, The method is applied to a clamp fastening device, which includes multiple motors, each of which outputs power to fasten a corresponding bolt in the clamp; the method includes: Control the multiple motors to tighten the corresponding bolts respectively until the tightening torque of each bolt reaches the preset standard torque; Check the parallelism of the mounting surface of the clamp; If the parallelism is greater than or equal to the preset parallelism, then the interval distance between the multiple bolts and the preset reference surface is obtained; The first bolt corresponding to the maximum value of the interval distance is determined, the first motor corresponding to the first bolt is determined, the second bolt is located on the opposite side of the first bolt, and the second motor corresponding to the second bolt is determined; The deflection angle is determined based on the deviation between the interval distance corresponding to the first bolt and the interval distance corresponding to the second bolt; The first motor is controlled to loosen the first bolt by the deflection angle, and the second motor is controlled to tighten the second bolt by the deflection angle.

2. The method according to claim 1, characterized in that, The control of the plurality of motors to tighten the corresponding bolts until the tightening torque of each bolt reaches a preset standard torque includes: The multiple motors are controlled to simultaneously tighten the corresponding bolts at preset speeds until the tightening torque of each bolt reaches the preset initial tightening torque; the initial tightening torque is less than the preset standard torque. The multiple motors are controlled to increase the tightening torque of each bolt by the same torque increase rate, starting from the initial tightening torque, until the tightening torque reaches the preset standard torque.

3. The method according to claim 1, characterized in that, The method of controlling the plurality of motors to tighten the corresponding bolts until the tightening torque of each bolt reaches the preset standard torque also includes: During the process of controlling the multiple motors to tighten the corresponding bolts, the current output by the multiple motors is collected respectively; Based on the multiple currents, a third motor and a fourth motor are identified as having deviations in the tightening torque output by the multiple motors; the first current corresponding to the third motor is greater than the second current corresponding to the fourth motor; Decrease the first current output by the third motor, and increase the second current output by the fourth motor; The multiple motors are controlled to tighten the corresponding bolts based on the adjusted current until the tightening torque of each bolt reaches the preset standard torque.

4. The method according to claim 3, characterized in that, The method of determining, based on multiple currents, that the third and fourth motors, respectively, have deviations in the tightening torque output by the multiple motors, includes: Calculate the current difference between any two of the multiple currents; Calculate the ratio between the maximum current difference among the plurality of current differences and the average value of the plurality of current differences; If the ratio is greater than the preset ratio, then the two motors corresponding to the maximum current difference are determined to be the third motor and the fourth motor, respectively.

5. The method according to claim 3, characterized in that, After collecting the current output by each of the multiple motors during the process of controlling the multiple motors to tighten the corresponding bolts, the method further includes: If the current does not meet the preset current constraint condition, then control the multiple motors to execute the target fault response action corresponding to the current constraint condition; If all of the currents satisfy the current constraint condition, then based on the multiple currents, the third motor and the fourth motor, which have deviations in the tightening torque output by the multiple motors, are determined.

6. The method according to claim 1, characterized in that, After controlling the plurality of motors to tighten the corresponding bolts until the tightening torque of each bolt reaches a preset standard torque, the process includes: Within a preset time period, the tightening torque of each bolt is maintained at the preset standard torque.

7. The method according to any one of claims 1-6, characterized in that, After controlling the first motor to loosen the first bolt by the deflection angle and controlling the second motor to tighten the second bolt by the deflection angle, the method further includes: Repeat the target step and all subsequent steps until the parallelism is less than the preset parallelism; the target step is to control the multiple motors to tighten the corresponding bolts until the tightening torque of each bolt reaches the preset standard torque.

8. The method according to claim 7, characterized in that, After repeatedly executing the target step and each subsequent step until the parallelism is less than the preset parallelism, the method further includes: Detect the contact resistance between the clamp and the connector; If the contact resistance is greater than the preset resistance, an ultrasonic vibration signal is sent to the contact surface between the clamp and the connector; After stopping the transmission of the ultrasonic vibration signal, the target step and all subsequent steps are repeated until the contact resistance is less than or equal to the preset resistance.

9. A clamp fastening device, comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, characterized in that, It also includes multiple motors, wherein when the processor executes the computer program, it implements the method as described in any one of claims 1 to 8, to control the multiple motors to output power for the corresponding bolts in the clamping hoop.

10. A computer program product, characterized in that, When the computer program product is run on the clamp fastening device, the clamp fastening device performs the method as described in any one of claims 1 to 8.

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