Multi-axis synchronous tightening device and control method thereof

Abstract

This application discloses a multi-axis synchronous tightening device and its control method, belonging to the field of bolt tightening equipment. The multi-axis synchronous tightening device includes a central multi-axis tightening controller and at least two servo tightening actuators electrically connected to it. The servo tightening actuator includes a servo motor, a reducer, a sensor, a sleeve, and an output head. The output head is connected to the output shaft of the reducer via a spline. The sensor is used to detect the torque and / or angle during the tightening process and feeds back the detection signal to the central multi-axis tightening controller in real time. According to the detection signals fed back by each sensor, the central multi-axis tightening controller performs staged synchronous tightening operations on each servo motor according to a preset tightening strategy, sequentially going through the cap-finding stage, the first pre-tightening stage, the second pre-tightening stage, and the final tightening stage. The controller judges the completion status at each stage. If the stage is not completed, the corresponding servo motor is shut down and an alarm is triggered to wait for manual handling. This helps to ensure multi-axis synchronous loading and improve the consistency of pre-tightening force.

Description

Technical Field

[0001] This application relates to the field of bolt tightening equipment technology, specifically a multi-axis synchronous tightening device and its control method, which is applicable to assembly scenarios in industries such as new energy vehicles, rail transit, commercial vehicles, aerospace, construction machinery, and valve manufacturing where multiple bolts need to be tightened simultaneously. Background Technology

[0002] In the field of mechanical assembly, many components (such as engine cylinder heads, battery pack end caps, brake discs, bogies, segments, valve bodies, etc.) require multiple bolts for fastening. Due to the elastic interaction between the bolts in a bolt group, if the bolts are tightened sequentially or each shaft is tightened independently, the preload of the bolts tightened first will loosen during the tightening of subsequent bolts. This can lead to uneven distribution of preload across the entire bolt group, leakage at the sealing surface, and reduced structural strength, directly affecting the assembly quality.

[0003] Existing methods for tightening bolts in groups mainly include single-axis servo tightening machines and multi-axis independent tightening equipment. Single-axis servo tightening machines require tightening each bolt one by one, which is not only inefficient but also results in poor consistency of preload for each bolt. Although multi-axis independent tightening equipment has multiple tightening axes, each axis operates independently according to its own program, lacking stage-level synchronous scheduling. This makes it difficult to ensure that each bolt is loaded synchronously under the same cycle and strategy, and the elastic interaction of the bolt group is not compensated, resulting in discrete preload and affecting assembly quality.

[0004] Therefore, this application provides a multi-axis synchronous tightening device and its control method to solve the above problems. Summary of the Invention

[0005] This application provides a multi-axis synchronous tightening device and its control method, aiming to solve the problems mentioned in the background art, such as the independent operation of each axis and the lack of stage-level synchronous scheduling when tightening multiple groups of bolts, which leads to the dispersion of bolt group preload and affects assembly quality.

[0006] To achieve the above objectives, this application provides the following technical solution: a multi-axis synchronous tightening device, comprising a central multi-axis tightening controller and at least two servo tightening actuators electrically connected to the central multi-axis tightening controller; The servo tightening actuator includes a servo motor, a reducer, a sensor, a sleeve, and an output head. The reducer is fixedly mounted on the drive end of the servo motor, and the input shaft of the reducer is drively connected to the drive shaft of the servo motor. The sensor is mounted on the output shaft of the reducer and fixedly connected to the reducer. The output head is connected to the end of the output shaft away from the reducer via a spline and rotates with the output shaft. The sleeve is mounted on the output head and fixedly connected to the sensor. The output head is rotatably connected to the sleeve, and the output head extends out of the end of the sleeve away from the sensor. The sensor is electrically connected to the input terminal of the central multi-axis tightening controller and is used to detect the torque and / or angle during the tightening process and feed the detection signal back to the central multi-axis tightening controller in real time. The servo motor is electrically connected to the output of the central multi-axis tightening controller. The central multi-axis tightening controller controls each servo motor to perform staged synchronous tightening operations according to a preset tightening strategy based on the detection signals fed back by each sensor.

[0007] Preferably, the tightening strategy includes at least one of the following: torque method, torque-angle method, angle-torque method, angle / torque dual-target method, yield point control method, or torque slope method.

[0008] Preferably, the staged synchronous tightening operation includes, in sequence, a cap-finding stage, a first pre-tightening stage, a second pre-tightening stage, and a final tightening stage; During the cap-finding stage, the central multi-axis tightening controller controls each servo motor to rotate based on the detection signals fed back by each sensor, so that each output head engages with the head of the corresponding bolt to be tightened. During the first pre-tightening stage, the central multi-axis tightening controller controls the rotation of each servo motor simultaneously based on the detection signals fed back by each sensor, and identifies the abnormal state of the bolt to be tightened. In the second pre-tightening stage, the central multi-axis tightening controller controls the rotation of each servo motor simultaneously based on the detection signals fed back by each sensor, so that each bolt to be tightened is properly engaged. In the final tightening stage, the central multi-axis tightening controller performs closed-loop control on each servo motor based on the detection signals fed back by each sensor, so that each bolt to be tightened rotates to the target torque and / or target angle, thus completing synchronous tightening.

[0009] Preferably, during the cap-finding stage, the central multi-axis tightening controller determines whether each output head is engaged with the head of the corresponding bolt to be tightened based on the detection signal fed back by each sensor. If any output head fails to engage within the timeout period, the central multi-axis tightening controller controls the servo motor corresponding to that output head to shut down and alarms to await manual handling. During the first pre-tightening stage, the central multi-axis tightening controller identifies the abnormal state of the bolt to be tightened based on the detection signals fed back by each of the sensors. If any bolt to be tightened remains in an abnormal state after a timeout, the central multi-axis tightening controller controls the servo motor corresponding to the bolt to be tightened to shut down and alarms to await manual handling. The abnormal state includes the bolt to be tightened being tilted, the bolt surface being defective, repeated tightening, or the bolt being misplaced. In the second pre-tightening stage, the central multi-axis tightening controller determines whether each bolt to be tightened is in place based on the detection signal fed back by each sensor. If any bolt to be tightened is not in place after a timeout, the central multi-axis tightening controller controls the servo motor corresponding to the bolt to be tightened to shut down and alarms to wait for manual handling. During the final tightening stage, the central multi-axis tightening controller determines whether each bolt to be tightened has rotated to the target torque and / or target angle based on the detection signals fed back by each sensor. If the tightening torque and / or tightening angle of any bolt exceeds the time limit and it still has not rotated to the target torque and / or target angle, the central multi-axis tightening controller controls the servo motor corresponding to the bolt to be tightened to shut down and alarms to wait for manual handling.

[0010] Preferably, the central multi-axis tightening controller is equipped with a deviation processing module and an axis shielding register; The deviation processing module is used to compare the detection signal fed back by each sensor in the same stage with a preset deviation threshold. When the detection signal fed back by any sensor exceeds the preset deviation threshold, the servo motor corresponding to that sensor is paused and the servo motor is put into a waiting state in order to coordinate the tightening rhythm of each servo motor. The axis shield register is used to shield the servo motor corresponding to the sensor when the sensor malfunctions or the feedback detection signal is abnormal.

[0011] Preferably, the sleeve is provided with a floating buffer mechanism inside; The floating buffer mechanism includes a centering rod inserted and fixed to the end of the output shaft away from the reducer, and a buffer spring fitted on the centering rod. The two ends of the buffer spring are respectively connected to the output head and the end of the output shaft away from the reducer.

[0012] Preferably, it also includes a human-machine interface (HMI) electrically connected to the central multi-axis tightening controller and an industrial communication interface electrically connected to the central multi-axis tightening controller for communicating with an external PLC and / or MES system.

[0013] This application also provides a control method for a multi-axis synchronous tightening device. Using the aforementioned multi-axis synchronous tightening device, the control method includes: S100, Parameter Settings: Tightening strategies, target torque, target rotation angle, detection thresholds for each stage, time for each stage, and synchronization deviation thresholds can be preset through the human-machine interface (HMI), external PLC, and / or MES system. S200, Cap-finding stage: Each sensor feeds back a detection signal to the central multi-axis tightening controller in real time. Based on the detection signal fed back by each sensor, the central multi-axis tightening controller simultaneously controls each servo motor to rotate, so that each output head engages with the head of the corresponding bolt to be tightened. The central multi-axis tightening controller determines whether each output head is engaged with the head of the corresponding bolt based on the detection signal fed back by each sensor. If any output head fails to engage within the timeout period, the central multi-axis tightening controller controls the servo motor corresponding to that output head to shut down and alarms to await manual handling. S300, First Pre-Tightening Stage: Each sensor feeds back a detection signal to the central multi-axis tightening controller in real time. The central multi-axis tightening controller controls each servo motor to rotate based on the detection signal fed back by each sensor, and identifies the abnormal state of the bolt to be tightened. If any bolt to be tightened remains in an abnormal state after a timeout, the central multi-axis tightening controller controls the servo motor corresponding to that bolt to shut down and issues an alarm, awaiting manual intervention. S400, Second Pre-Tightening Stage: Each sensor feeds back a detection signal to the central multi-axis tightening controller in real time. Based on the detection signal fed back by each sensor, the central multi-axis tightening controller simultaneously controls each servo motor to rotate, so that each bolt to be tightened is properly engaged. Among them, the central multi-axis tightening controller determines whether each bolt to be tightened is in place based on the detection signal fed back by each sensor. If any bolt to be tightened fails to be in place within the time limit, the central multi-axis tightening controller controls the servo motor corresponding to the bolt to be tightened to shut down and alarms to wait for manual handling. S500, Final Tightening Stage: Each sensor feeds back detection signals to the central multi-axis tightening controller in real time. The central multi-axis tightening controller performs closed-loop control on each servo motor based on the detection signals fed back by each sensor, so that each bolt to be tightened rotates to the target torque and / or target angle, completing synchronous tightening. Among them, the central multi-axis tightening controller determines whether the tightening torque and / or tightening angle of each bolt to be tightened has reached the target value based on the detection signals fed back by each sensor. If the tightening torque and / or tightening angle of any bolt to be tightened fails to rotate to the target torque and / or target angle within the time limit, the central multi-axis tightening controller controls the servo motor corresponding to the bolt to be tightened to shut down and alarms to wait for manual handling.

[0014] Preferably, in the cap-finding stage, the first pre-tightening stage, the second pre-tightening stage, and the final tightening stage, the central multi-axis tightening controller determines that the state of each bolt to be tightened is consistent based on the detection signals fed back by each of the sensors, and then controls each of the servo motors to rotate to enter the next stage.

[0015] Preferably, in the cap-finding stage, the first pre-tightening stage, the second pre-tightening stage and the final tightening stage, the deviation processing module compares the detection signal fed back by each sensor with a preset deviation threshold. When the detection signal fed back by any sensor exceeds the preset deviation threshold, the servo motor corresponding to that sensor is paused and the servo motor is put into a waiting state in order to coordinate the tightening rhythm of each servo motor. When the sensor malfunctions or the feedback detection signal is abnormal, the central multi-axis tightening controller's control axis shield register will shield the servo motor corresponding to the sensor, causing the corresponding servo tightening actuator to exit multi-axis synchronous tightening operation.

[0016] This application uses a single central multi-axis tightening controller to uniformly manage all servo tightening actuators, strictly following the phased operation of cap finding, first pre-tightening, second pre-tightening, and final tightening. Only when all participating tightening axes complete the current stage will they uniformly jump to the next stage. This effectively overcomes the defect of dispersed pre-tightening force caused by the elastic interaction between bolt groups during traditional multi-axis independent asynchronous tightening, enabling synchronous and uniform loading of bolt groups, and improving the sealing performance and structural reliability after assembly.

[0017] In this application, the servo tightening actuator integrates a floating buffer mechanism, which relies on a centering rod and a buffer spring to achieve axial elastic floating. This can compensate for the positioning errors of the tooling, robot, and workpiece, and avoid rigid impact when the sleeve is connected to the bolt. This not only prevents damage to the bolt threads but also protects the output sensor and extends the service life of the equipment.

[0018] This application, by setting up a deviation processing module and an axis shielding register, can pause the faster-moving axis and wait for alignment when the torque or angle progress of some axes deviates during the same tightening stage, thus maintaining the synchronous cycle of multiple axes. When a single-axis sensor fails or the signal is abnormal, the faulty axis can be shielded and made to exit synchronous operation, while the remaining servo tightening actuators can continue to complete the work. This prevents the entire machine from being completely shut down due to a single-axis failure, reducing production line downtime losses and adapting to continuous industrial production scenarios. Attached Figure Description

[0019] Figure 1 This is a system framework diagram of a multi-axis synchronous tightening device; Figure 2 A schematic diagram of the central multi-axis tightening controller in a multi-axis synchronous tightening device; Figure 3 This is a schematic diagram of the servo tightening actuator in a multi-axis synchronous tightening device; Figure 4 This is a partial cross-sectional view of the servo tightening actuator in a multi-axis synchronous tightening device.

[0020] In the picture: 100. Central multi-axis tightening controller; 110. Deviation processing module; 120. Axis Mask Register; 200. Servo tightening actuator; 210. Servo motor; 220. Speed ​​reducer; 230. Sensors; 240. Sleeve; 250. Output head; 260. Floating buffer mechanism; 261. Centering rod; 262. Buffer spring; 300. Human-Computer Interface (HMI); 400. Industrial communication interface. Detailed Implementation

[0021] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0022] This application provides a multi-axis synchronous tightening device, which is mainly used in high-end manufacturing scenarios such as automobile engine cylinder heads, chassis brackets, aerospace precision components, and rail transit tunnel segments, where multiple bolts need to be tightened simultaneously.

[0023] like Figure 1-4 As shown, the multi-axis synchronous tightening device includes a central multi-axis tightening controller 100 and at least two servo tightening actuators 200 electrically connected to the central multi-axis tightening controller 100. The servo tightening actuators 200 serve as synchronous slave stations, and the central multi-axis tightening controller 100 serves as the synchronous master station. In this embodiment, the number of servo tightening actuators 200 can be flexibly configured according to the number of bolt holes in the actual workpiece, such as 2 axes, 4 axes, 6 axes, 8 axes, or even 16 axes. The central multi-axis tightening controller 100 provides unified control, thereby effectively reducing hardware costs, reducing system failure points, and achieving millisecond-level multi-axis synchronous control.

[0024] The servo tightening actuator 200 is the core component for realizing the tightening action, such as... Figure 3 As shown, the servo tightening actuator 200 includes a servo motor 210, a reducer 220, a sensor 230, a sleeve 240, and an output head 250. The reducer 220 is fixedly mounted on the drive end of the servo motor 210, and its input shaft is drively connected to the drive shaft of the servo motor 210, converting the high speed of the servo motor 210 into high torque output. The sensor 230 is mounted on the output shaft 221 of the reducer 220 and fixedly connected to it. This sensor 230 is preferably a high-precision torque / angle sensor, used to detect torque and / or angle data in real time during the tightening process. The output head 250 is splined to the end of the output shaft 221 away from the reducer 220 and rotates with the output shaft 221. The shape of the output head 250 can be customized according to the head shape of the bolt to be tightened (e.g., internal hexagon, external hexagon, spline, etc.). The sleeve 240 is fitted onto the output head 250 and fixedly connected to the sensor 230. The output head 250 is rotatably connected to the sleeve 240, and the output head 250 extends from the end of the sleeve 240 away from the sensor 230, so that it can engage with the bolt to be tightened, thereby realizing the tightening operation of the bolt.

[0025] Sensor 230 is electrically connected to the input of the central multi-axis tightening controller 100, used to detect the torque and / or angle during the tightening process and feed the detection signal back to the central multi-axis tightening controller 100 in real time; servo motor 210 is electrically connected to the output of the central multi-axis tightening controller 100, and the central multi-axis tightening controller 100 controls each servo motor 210 to perform staged synchronous tightening operations according to a preset tightening strategy based on the detection signal fed back by each sensor 230. During operation, the servo motor 210 provides high-speed rotational power, which is reduced and amplified by the reducer 220 before being transmitted to the output head 250 by the output shaft 221; the sensor 230 detects the torque and / or angle transmitted by the output shaft 221 in real time and feeds it back to the central multi-axis tightening controller 100, forming a closed-loop control of torque and / or angle.

[0026] Furthermore, to accommodate minor deviations in bolt hole positions during actual assembly and to prevent bolt stripping or misalignment due to rigid connections, such as... Figure 4 As shown, a floating buffer mechanism 260 is provided inside the sleeve 240. The floating buffer mechanism 260 includes a centering rod 261 that is inserted and fixed to the end of the output shaft 221 away from the reducer 220, and a buffer spring 262 fitted on the centering rod 261. The two ends of the buffer spring 262 are respectively connected to the output head 250 and the end of the output shaft 221 away from the reducer 220. The axial floating stroke of the floating buffer mechanism 260 is set to 20mm-50mm. Axial elastic floating is achieved by relying on the buffer spring 262, which can compensate for positional deviations caused by tooling, robot, or workpiece positioning, eliminate the impact caused by rigid docking, and greatly improve the success rate of cap finding and tightening.

[0027] In addition, the multi-axis synchronous tightening device also includes a human-machine interface (HMI) 300 electrically connected to the central multi-axis tightening controller 100, and an industrial communication interface 400 electrically connected to the central multi-axis tightening controller 100 for communication with external PLCs and / or MES systems. In this embodiment, the industrial communication interface 400 can adopt Modbus TCP or EtherCAT. Operators can intuitively set tightening strategies, tightening parameters, monitor tightening status, and view tightening curves through the HMI 300. At the same time, the industrial communication interface 400 can seamlessly connect to the factory's automated production line to achieve remote data access and single-piece traceability of assembly data.

[0028] The central multi-axis tightening controller 100 supports various advanced tightening strategies, including but not limited to at least one of the following: torque method, torque-angle method, angle-torque method, angle / torque dual-target method, yield point control method, or torque slope method. Specifically, the torque method uses reaching the target torque as the tightening termination condition; the torque-angle method uses the angle increment as the termination condition after the torque reaches a set threshold; the angle-torque method prioritizes angle and verifies torque; the angle / torque dual-target method requires both torque and angle to reach their target values; the yield point control method determines the yield point and stops tightening based on the change in the slope of the torque-angle curve; and the torque slope method uses changes in the torque slope for process control. Single or multiple combinations of tightening strategies can be selected based on bolt material, specifications, friction coefficient, and assembly process requirements.

[0029] To achieve high-precision synchronous tightening, this embodiment divides the tightening process into four sequential stages: the cap-finding stage, the first pre-tightening stage, the second pre-tightening stage, and the final tightening stage.

[0030] During the cap-finding stage, the central multi-axis tightening controller 100 simultaneously controls each servo motor 210 to rotate at a low speed, driving the output head 250 to find and engage the head of the bolt to be tightened. Based on the detection signals fed back by each sensor 230, the central multi-axis tightening controller 100 determines whether each output head 250 is engaged with the head of the corresponding bolt to be tightened. If any output head 250 fails to engage within a preset time (timeout), it indicates that the axis alignment has failed. The central multi-axis tightening controller 100 will control the servo motor 210 to shut down and sound an alarm, awaiting manual intervention. Other axes that have successfully engaged can remain in a waiting or paused state. After all servo tightening actuators 200 have completed cap-finding, the central multi-axis tightening controller 100 issues a jump command, and all axes synchronously enter the first pre-tightening stage.

[0031] In the first pre-tightening stage, the central multi-axis tightening controller 100 controls all servo motors 210 to synchronously accelerate and rotate for initial pre-tightening. During this stage, the central multi-axis tightening controller 100 identifies abnormal conditions of the bolts to be tightened based on detection signals fed back by the sensors 230, such as bolt tilting, poor bolt surface, repeated tightening, or misplaced bolts. If an abnormality is detected on a certain axis and is not eliminated within a timeout period, the corresponding servo motor 210 is shut down and an alarm is triggered, awaiting manual intervention. After all axes have completed their pre-tightening, the system switches to the second pre-tightening stage.

[0032] In the second pre-tightening stage, the central multi-axis tightening controller 100 continues to control all servo motors 210 to rotate synchronously, so that each bolt to be tightened is in place. In this stage, the central multi-axis tightening controller 100 determines whether each bolt to be tightened is in place based on the detection signal fed back by each sensor 230. If any bolt to be tightened is not in place after a timeout, the central multi-axis tightening controller 100 controls the servo motor 210 corresponding to the bolt to be tightened to shut down and alarms to wait for manual handling. After all axes are aligned, the final tightening stage begins.

[0033] In the final tightening stage, the central multi-axis tightening controller 100 performs closed-loop control on each of the servo motors 210, causing each bolt to be tightened to rotate to the target torque and / or target angle, thus completing synchronous tightening. During this process, the central multi-axis tightening controller 100 determines whether each bolt to be tightened has rotated to the target torque and / or target angle based on the detection signals fed back by each of the sensors 230. If any bolt fails to rotate to the target torque and / or target angle within the timeout period, the central multi-axis tightening controller 100 controls the servo motor 210 corresponding to that bolt to be tightened to shut down and triggers an alarm, awaiting manual intervention. The remaining axes then select to continue operation or stop synchronously according to preset logic.

[0034] It is understandable that during multi-axis synchronous tightening, slight progress deviations may inevitably occur between the axes due to mechanical transmission clearances, individual bolt differences, or sensor errors.

[0035] To address this issue, the central multi-axis tightening controller 100 includes a deviation processing module 110 and an axis shielding register 120. The deviation processing module 110 monitors the detection signals fed back by each sensor 230 within the same stage in real time and compares them with a preset deviation threshold. When the detection signal fed back by any sensor 230 (such as the current torque value or angle value) exceeds the preset deviation threshold, it indicates that the tightening progress of that axis has fallen behind that of the other axes. At this time, the deviation processing module 110 pauses the servo motor 210 corresponding to that sensor 230 and performs a waiting operation on that servo motor 210 until the progress of the other axes catches up or the deviation returns to the threshold range, thereby coordinating the tightening rhythm of each servo motor 210 and ensuring multi-axis synchronization.

[0036] The axis shield register 120 is used to handle sudden failures. When a sensor 230 on a certain axis malfunctions or the feedback detection signal shows a serious abnormality (such as signal loss or value jump), the central multi-axis tightening controller 100 will control the axis shield register 120 to shield the servo motor 210 corresponding to the faulty axis, causing it to exit the current multi-axis synchronous tightening operation. This can prevent a single point of failure from causing the scrapping of an entire batch of workpieces or equipment damage, improving the system's fault tolerance and production continuity.

[0037] This application also provides a control method for a multi-axis synchronous tightening device. Using the aforementioned multi-axis synchronous tightening device, the control method includes the following steps: S100, Parameter Settings: Through the human-machine interface HMI300, external PLC and / or MES system, the tightening strategy (such as torque method), target torque, target rotation angle, detection threshold for each stage (such as cap-finding torque threshold, abnormal state torque slope threshold), time for each stage and synchronization deviation threshold are preset, and the bolt abnormal judgment conditions, synchronization deviation threshold and timeout threshold are pre-entered into the central multi-axis tightening controller 100. S200, Cap-finding stage: The central multi-axis tightening controller 100 simultaneously controls each servo motor 210 to rotate at low speed. Each sensor 230 feeds back detection signals to the central multi-axis tightening controller 100 in real time. Based on the detection signals fed back by each sensor 230, the central multi-axis tightening controller 100 causes each output head 250 to engage with the head of the corresponding bolt to be tightened. During this process, the central multi-axis tightening controller 100 determines whether each output head 250 is engaged with the head of the corresponding bolt based on the detection signals fed back by each sensor 230. If any output head 250 fails to engage within the timeout period, the central multi-axis tightening controller 100 controls the servo motor 210 corresponding to that output head 250 to shut down and triggers an alarm, awaiting manual intervention. After all servo tightening actuators 200 have completed cap-finding, the central multi-axis tightening controller 100 issues a jump command, and all axes synchronously enter the next tightening stage.

[0038] S300, First Pre-Tightening Stage: The central multi-axis tightening controller 100 controls all servo motors 210 to synchronously accelerate and rotate for initial pre-tightening. During this process, the central multi-axis tightening controller 100 identifies abnormal states of the bolts to be tightened based on detection signals fed back by the sensors 230, such as bolt tilting, poor bolt surface, repeated tightening, or misplaced bolts. If an abnormality is detected on a certain axis and is not eliminated within a timeout period, the corresponding servo motor 210 is shut down and an alarm is triggered, awaiting manual intervention. After all axes are completed, the system switches to the next tightening stage.

[0039] S400, Second Pre-Tightening Stage: The central multi-axis tightening controller 100 continues to control all servo motors 210 to rotate synchronously, so that each bolt to be tightened is in place; during this process, the central multi-axis tightening controller 100 determines whether each bolt to be tightened is in place based on the detection signal fed back by each of the sensors 230. If any bolt to be tightened is not in place after a timeout, the central multi-axis tightening controller 100 controls the servo motor 210 corresponding to the bolt to be tightened to shut down and alarms to wait for manual handling. After all axes are aligned, the final tightening stage begins.

[0040] S500, Final Tightening Stage: The central multi-axis tightening controller 100 performs closed-loop control on each of the servo motors 210, causing each bolt to be tightened to rotate to the target torque and / or target angle, completing synchronous tightening. During this process, the central multi-axis tightening controller 100 determines whether each bolt to be tightened has rotated to the target torque and / or target angle based on the detection signals fed back by each of the sensors 230. If any bolt fails to rotate to the target torque and / or target angle within the timeout period, the central multi-axis tightening controller 100 controls the servo motor 210 corresponding to that bolt to be tightened to shut down and triggers an alarm, awaiting manual intervention. The remaining axes select to continue operation or stop synchronously according to preset logic.

[0041] In each of the stages S200 to S500 described above, the central multi-axis tightening controller 100 will judge the status of each bolt to be tightened in real time. When all axes in the working state meet the completion conditions of the current stage (consistent status), the controller controls each servo motor 210 to rotate synchronously to enter the next stage.

[0042] Meanwhile, in each stage from S200 to S500, the deviation processing module 110 continuously operates, comparing the detection signals fed back by each sensor 230 with preset deviation thresholds. When the detection signal fed back by any sensor 230 exceeds the preset deviation threshold, the servo motor 210 corresponding to that sensor 230 is paused and put into a waiting state to coordinate the tightening rhythm of each servo motor 210. If a sensor 230 malfunctions or its feedback signal is abnormal during operation, the central multi-axis tightening controller 100 controls the axis shielding register 120 to shield the corresponding servo motor 210, causing it to exit multi-axis synchronous tightening operation, while the remaining normal axes continue to complete the synchronous tightening task.

[0043] The above description is merely a preferred embodiment of this application, but the scope of protection of this application is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in this application, based on the technical solution and concept of this application, should be included within the scope of protection of this application.

Claims

1. A multi-axis synchronous tightening device, characterized in that: Includes a central multi-axis tightening controller (100) and at least two servo tightening actuators (200) electrically connected to the central multi-axis tightening controller (100); The servo tightening actuator (200) includes a servo motor (210), a reducer (220), a sensor (230), a sleeve (240), and an output head (250). The reducer (220) is fixedly mounted on the drive end of the servo motor (210), and the input shaft of the reducer (220) is connected to the drive shaft of the servo motor (210). The sensor (230) is mounted on the output shaft (221) of the reducer (220) and is connected to the reducer. (220) Fixed connection, the output head (250) is connected to the end of the output shaft (221) away from the reducer (220) by a spline, and rotates with the output shaft (221); the sleeve (240) is fitted on the output head (250) and fixedly connected to the sensor (230), the output head (250) is rotatably connected to the sleeve (240), and the output head (250) extends out of the end of the sleeve (240) away from the sensor (230); The sensor (230) is electrically connected to the input terminal of the central multi-axis tightening controller (100) and is used to detect the torque and / or angle during the tightening process and feed the detection signal back to the central multi-axis tightening controller (100) in real time. The servo motor (210) is electrically connected to the output of the central multi-axis tightening controller (100). The central multi-axis tightening controller (100) controls each servo motor (210) to perform stage-level synchronous tightening operation according to the detection signal fed back by each sensor (230) and a preset tightening strategy.

2. The multi-axis synchronous tightening device according to claim 1, characterized in that: The tightening strategy includes at least one of the following: torque method, torque-angle method, angle-torque method, angle / torque dual-target method, yield point control method, or torque slope method.

3. The multi-axis synchronous tightening device according to claim 1, characterized in that: The staged synchronous tightening operation includes, in sequence, a cap-finding stage, a first pre-tightening stage, a second pre-tightening stage, and a final tightening stage; During the cap-finding stage, the central multi-axis tightening controller (100) controls each servo motor (210) to rotate according to the detection signal fed back by each sensor (230), so that each output head (250) engages with the head of the corresponding bolt to be tightened. During the first pre-tightening stage, the central multi-axis tightening controller (100) controls each servo motor (210) to rotate based on the detection signals fed back by each of the sensors (230) to identify the abnormal state of the bolt to be tightened; In the second pre-tightening stage, the central multi-axis tightening controller (100) controls each servo motor (210) to rotate according to the detection signal fed back by each of the sensors (230), so that each bolt to be tightened fits in place; In the final tightening stage, the central multi-axis tightening controller (100) performs closed-loop control on each servo motor (210) based on the detection signals fed back by each of the sensors (230), so that each bolt to be tightened rotates to the target torque and / or target angle, and completes synchronous tightening.

4. The multi-axis synchronous tightening device according to claim 3, characterized in that: During the cap-finding stage, the central multi-axis tightening controller (100) determines whether each output head (250) is engaged with the head of the corresponding bolt to be tightened based on the detection signal fed back by each sensor (230). If any output head (250) fails to engage within the time limit, the central multi-axis tightening controller (100) controls the servo motor (210) corresponding to that output head (250) to shut down and alarms to wait for manual processing. During the first pre-tightening stage, the central multi-axis tightening controller (100) identifies the abnormal state of the bolt to be tightened based on the detection signals fed back by each of the sensors (230). If any bolt to be tightened remains in an abnormal state after a timeout, the central multi-axis tightening controller (100) controls the servo motor (210) corresponding to the bolt to be tightened to shut down and alarms to await manual handling. The abnormal state includes the bolt being tilted, the bolt surface being defective, repeated tightening, or the bolt being misplaced. In the second pre-tightening stage, the central multi-axis tightening controller (100) determines whether each bolt to be tightened is in place based on the detection signal fed back by each sensor (230). If any bolt to be tightened is not in place after a timeout, the central multi-axis tightening controller (100) controls the servo motor (210) corresponding to the bolt to be tightened to shut down and alarms to wait for manual handling. During the final tightening stage, the central multi-axis tightening controller (100) determines whether each bolt to be tightened has rotated to the target torque and / or target angle based on the detection signal fed back by each of the sensors (230). If the tightening torque and / or tightening angle of any bolt to be tightened exceeds the time limit and it still has not rotated to the target torque and / or target angle, the central multi-axis tightening controller (100) controls the servo motor (210) corresponding to the bolt to be tightened to shut down and alarms to wait for manual handling.

5. The multi-axis synchronous tightening device according to claim 3, characterized in that: The central multi-axis tightening controller (100) is equipped with a deviation processing module (110) and an axis shielding register (120). The deviation processing module (110) is used to compare the detection signal fed back by each sensor (230) in the same stage with a preset deviation threshold. When the detection signal fed back by any sensor (230) exceeds the preset deviation threshold, the servo motor (210) corresponding to the sensor (230) is paused and the servo motor (210) is put into waiting mode to coordinate the tightening rhythm of each servo motor (210). The axis shield register (120) is used to shield the servo motor (210) corresponding to the sensor (230) when the sensor (230) malfunctions or the feedback detection signal is abnormal.

6. The multi-axis synchronous tightening device according to claim 1, characterized in that: The sleeve (240) is provided with a floating buffer mechanism (260) inside. The floating buffer mechanism (260) includes a centering rod (261) inserted and fixed to the end of the output shaft (221) away from the reducer (220) and a buffer spring (262) fitted on the centering rod (261). The two ends of the buffer spring (262) are respectively connected to the output head (250) and the end of the output shaft (221) away from the reducer (220).

7. The multi-axis synchronous tightening device according to claim 1, characterized in that: It also includes a human-machine interface (HMI) (300) electrically connected to the central multi-axis tightening controller (100) and an industrial communication interface (400) electrically connected to the central multi-axis tightening controller (100) for communicating with an external PLC and / or MES system.

8. A control method for a multi-axis synchronous tightening device, employing the multi-axis synchronous tightening device according to any one of claims 1-7, characterized in that: The control method includes: S100, Parameter settings: Through the human-machine interface HMI (300), external PLC and / or MES system, preset tightening strategy, target torque, target rotation angle, detection threshold for each stage, time for each stage and synchronization deviation threshold; S200, Cap-finding stage: Each sensor (230) feeds back a detection signal to the central multi-axis tightening controller (100) in real time. The central multi-axis tightening controller (100) controls each servo motor (210) to rotate according to the detection signal fed back by each sensor (230), so that each output head (250) engages with the head of the corresponding bolt to be tightened. The central multi-axis tightening controller (100) determines whether each output head (250) engages with the head of the corresponding bolt according to the detection signal fed back by each sensor (230). If any output head (250) fails to engage within the time limit, the central multi-axis tightening controller (100) controls the servo motor (210) corresponding to that output head (250) to shut down and alarms to wait for manual handling. S300, First pre-tightening stage: Each sensor (230) feeds back a detection signal to the central multi-axis tightening controller (100) in real time. The central multi-axis tightening controller (100) controls each servo motor (210) to rotate according to the detection signal fed back by each sensor (230) and identifies the abnormal state of the bolt to be tightened. The central multi-axis tightening controller (100) identifies the abnormal state of the bolt to be tightened according to the detection signal fed back by each sensor (230). If any bolt to be tightened is still in an abnormal state after a timeout, the central multi-axis tightening controller (100) controls the servo motor (210) corresponding to the bolt to be tightened to shut down and alarms to wait for manual handling. S400, Second Pre-Tightening Stage: Each sensor (230) feeds back a detection signal to the central multi-axis tightening controller (100) in real time. The central multi-axis tightening controller (100) controls each servo motor (210) to rotate according to the detection signal fed back by each sensor (230), so that each bolt to be tightened is in place. The central multi-axis tightening controller (100) determines whether each bolt to be tightened is in place according to the detection signal fed back by each sensor (230). If any bolt to be tightened is not in place after a timeout, the central multi-axis tightening controller (100) controls the servo motor (210) corresponding to the bolt to be tightened to shut down and alarms to wait for manual handling. S500, Final Tightening Stage: Each sensor (230) feeds back a detection signal to the central multi-axis tightening controller (100) in real time. The central multi-axis tightening controller (100) performs closed-loop control on each servo motor (210) based on the detection signal fed back by each sensor (230), so that each bolt to be tightened rotates to the target torque and / or target angle to complete synchronous tightening. The central multi-axis tightening controller (100) determines whether the tightening torque and / or tightening angle of each bolt to be tightened reaches the target value based on the detection signal fed back by each sensor (230). If the tightening torque and / or tightening angle of any bolt to be tightened fails to rotate to the target torque and / or target angle within the time limit, the central multi-axis tightening controller (100) controls the servo motor (210) corresponding to the bolt to be tightened to shut down and alarms to wait for manual handling.

9. The control method for the multi-axis synchronous tightening device according to claim 8, characterized in that: In the cap-finding stage, the first pre-tightening stage, the second pre-tightening stage and the final tightening stage, the central multi-axis tightening controller (100) determines that the state of each bolt to be tightened is consistent based on the detection signal fed back by each of the sensors (230), and then controls each of the servo motors (210) to rotate to enter the next stage.

10. The control method for the multi-axis synchronous tightening device according to claim 8, characterized in that: In the cap-finding stage, the first pre-tightening stage, the second pre-tightening stage and the final tightening stage, the deviation processing module (110) compares the detection signal fed back by each sensor (230) with the preset deviation threshold. When the detection signal fed back by any sensor (230) exceeds the preset deviation threshold, the servo motor (210) corresponding to that sensor (230) is paused and the servo motor (210) is put into waiting mode to coordinate the tightening rhythm of each servo motor (210). When the sensor (230) malfunctions or the feedback detection signal is abnormal, the central multi-axis tightening controller (100) controls the axis shielding register (120) to shield the servo motor (210) corresponding to the sensor (230), causing the corresponding servo tightening actuator to exit multi-axis synchronous tightening operation.

Images