Automatic assembling mechanism for railway track fastener nuts

Abstract

The invention discloses an automatic assembling mechanism for railway track fastener nuts, and belongs to the technical field of automatic assembling equipment. The mechanism comprises a mechanical arm, a nut assembling mechanism, a power transmission device, a propelling device, a connecting seat and a visual device, the nut assembling mechanism is composed of a compliant device and a magnetic attraction device, the tail end of a mechanical arm is fixed through a connecting base, a visual device recognizes the position of a fastener in real time and guides the mechanical arm to be positioned, a servo motor transmits torque through a speed reducer and a telescopic universal connecting assembly, nut screwing is achieved, and the compliant device absorbs assembling errors and adapts to the posture. The magnetic attraction device is used for adsorbing and fixing the nut; the six-dimensional force sensor is used for monitoring and feeding back torque in real time; the control system is used for adjusting pre-tightening force; the propelling device is used for applying axial thrust; the device can realize automatic identification, positioning, tightening and pre-tightening control of the nut, and is suitable for various sleeper structures and complex track working conditions.

Description

Technical Field

[0001] This invention belongs to the field of automated assembly equipment technology, and relates to an automated assembly mechanism for railway track fastener nuts, which is suitable for the automatic identification, gripping, positioning and tightening of railway track fastener nuts. Background Technology

[0002] The railway fastening system consists of fastening components, elastic pads, fasteners, and gauge baffles. It is used to reliably fix the rails to the sleepers, bear and transmit the dynamic loads generated by train operation, and ensure the stability of track geometry and the safety of train operation. The quality of fastening assembly directly affects the stability of the track structure and operational safety.

[0003] Currently, the assembly of nuts and fasteners mainly relies on manual operation, which not only consumes a lot of manpower but also results in low efficiency, poor accuracy, and high labor intensity due to the influence of workers' experience on assembly quality. Therefore, there is an urgent need for an intelligent device that can automatically identify, grasp, position, and assemble nuts to improve work efficiency and quality, reduce labor intensity, and promote the intelligent and automated development of railway construction and maintenance.

[0004] The automated assembly mechanism provided by this invention can replace manual operation. Through visual recognition and intelligent control system, it can automatically grasp, accurately position and flexibly tighten nuts, ensure the consistency of assembly preload, improve the assembly efficiency and quality of rail fasteners, and is suitable for various working conditions and sleeper structures, further promoting the intelligent development of rail fastener assembly operations. Summary of the Invention

[0005] To address the problems mentioned in the technical background, this invention provides an automated assembly mechanism for railway track fastener nuts, which will effectively reduce the number of personnel and labor intensity required for railway track laying and replacement operations, while improving work efficiency and quality. This mechanism integrates visual recognition, intelligent control, mechanical execution, and torque feedback control functions, enabling automatic identification and gripping, precise positioning, flexible tightening, and adaptive torque control of track fastener nuts. It is suitable for various sleeper types and complex construction environments, significantly improving work efficiency while ensuring assembly quality.

[0006] This invention provides an automated assembly mechanism for railway track fastener nuts, characterized by: a robotic arm, a nut assembly mechanism, a base plate, a power transmission device, a propulsion device, a connecting seat, and a vision inspection and recognition device; the nut assembly mechanism consists of a compliant device and a magnetic attraction device; the nut assembly mechanism includes a mounting seat, an electric slip ring, a power transmission shaft, rolling bearings, bearing seats, an input end coupling flange, an output end coupling flange, a universal joint coupling, a compression spring, a six-dimensional force sensor, a fixed seat, a magnetic sleeve, and a ring magnet; the propulsion device includes a DC brushless geared motor, a motor mounting plate, a slide rail mounting seat, a slide rail, a slider, a stop block, a bent plate, a propulsion plate, a flange seat, a linear bearing, a sliding bearing, and a circular plate; the robotic arm and the power transmission device are both vertically mounted on the base plate; the nut assembly mechanism, the power transmission device, and the propulsion device constitute a cross-domain coupled composite assembly system, in which... The system forms a composite assembly system that integrates rigid transmission, compliant adjustment, magnetic field centralization, and visual guidance. Based on the fusion of five modal information (force, position, angle, torque, and vision), it achieves trajectory self-adaptation, misalignment absorption, and disturbance suppression to adapt to conditions such as bolt axial error, radial offset, spike tilt, and rail surface deformation. The nut assembly mechanism is fixed to the end of the robotic arm via a connecting seat, providing six-dimensional spatial positioning and vibration resistance. The propulsion device is connected and fixed to the lower end of the fixed seat via a motor mounting plate, synchronizing the axial propulsion force with the thread engagement state in real time. The visual detection and recognition device uses a binocular camera mounted above the nut assembly mechanism, parallel to its end, to acquire three-dimensional images of the track fastener area and form a dual closed-loop control system with attitude feedforward and mechanical feedback with the six-dimensional force sensor. The power transmission device provides torque output to the nut under the action of the compliant mechanism to complete the nut assembly.

[0007] The working principle of this invention is as follows: The nut assembly mechanism is fixed to the end of the robotic arm via a connecting seat. A binocular vision detection device is installed above the nut assembly mechanism and maintains a parallel viewing angle to acquire a three-dimensional image of the fastener area. The vision controller performs feature extraction and pose recognition on the image, calculates the deviation between the actual image and the desired image, and outputs an error signal to the motion controller. The robotic arm adjusts its posture according to the control command, ensuring that the nut assembly mechanism is precisely aligned with the position of the bolt to be installed. When the robotic arm reaches the predetermined position, the servo motor transmits torque through the planetary reducer and the retractable universal joint assembly to achieve nut screwing. The retractable universal joint assembly is used to compensate for axis and position errors to ensure transmission stability; the compliant device absorbs assembly deviations and uneven force, achieving posture self-adjustment and avoiding thread mis-threading and jamming. The magnetic suction device attracts and fixes the nut, and the six-dimensional force sensor detects the torque in real time and feeds it back to the control system to achieve adaptive torque adjustment, ensuring consistent nut preload. The propulsion device is designed to apply an axial pushing force to the compression spring during the assembly stage. This causes the compression spring to elastically deform under force and continuously provide downward pressure, thereby ensuring sufficient axial clamping force on the nut during tightening, preventing loosening and improving assembly reliability. After assembly is completed, the robotic arm moves to the next fastener position and begins the cycle.

[0008] As a further technical solution, the robotic arm is preferably an Aobo six-degree-of-freedom robot driven by a servo motor; the control system includes a main power supply, a computer power supply unit, a computer control module, an input / output board, a user connection port, control boards for each axis, and a servo drive unit, used to achieve high-precision positioning control of multiple degrees of freedom, and to complete the automatic identification, positioning, and assembly guidance of the nut based on a binocular vision recognition and control algorithm; the robotic arm is fixedly mounted on the base plate by bolts; the cylindrical surface of the connecting seat is provided with several bolt holes, which are reliably connected to the end of the robotic arm by bolts, and bolt holes are respectively provided on the left and right sides of the connecting seat, which are bolted to the sides of the mounting seat to achieve stable support; the vision system adopts... A binocular camera, fixedly mounted on the mounting base, is used to acquire stereo images of the track fastener area and output spatial pose information. The power transmission device includes a servo motor, a planetary reducer, a rigid coupling, and a retractable universal joint assembly. The servo motor is bolted to the base plate and coaxially connected to the planetary reducer to achieve efficient power transmission and speed matching. The retractable universal joint assembly includes an outer cylinder, a sliding inner shaft, and an angular offset compensation unit to compensate for axial offset and track spike tilt angle. The power transmission device uses the servo motor torque and the radial force, axial force, and torque feedback from a six-dimensional force sensor to determine the engagement depth and adjust the torque threshold and assembly parameters in real time.

[0009] As a further technical solution, the nut assembly mechanism is equipped with a compliant device; the compliant device includes a fixed module and a flexible module; the fixed module includes a mounting base, an electric slip ring, a power transmission shaft, a bearing housing, and a rolling bearing; the fixed module reduces rotational runout through a bearing support structure, enabling the compliant module to maintain a stable power transmission path under high load conditions; the electric slip ring is fixedly installed on the mounting base, and its output end is connected to the power transmission shaft to realize continuous transmission of electrical signals and electrical energy during rotation; the bearing housing is fixedly connected to the lower end of the mounting base by bolts, and the rolling bearing is installed in the bearing housing to support the rotation of the power transmission shaft and reduce rotational friction, thereby ensuring the smoothness and reliability of the transmission; the flexible module in the nut assembly mechanism includes a power transmission shaft .... The system comprises an inlet coupling flange, an outlet coupling flange, a universal joint coupling, a compression spring, and a six-dimensional force sensor. The universal joint coupling compensates for angular deviations and prevents jamming caused by shaft misalignment, providing low-frequency angular compensation capability for the flexible module. The compression spring exhibits nonlinear segmented stiffness characteristics, displaying low stiffness energy absorption characteristics in the initial engagement stage and high stiffness anti-eccentric load capability in the stable thread engagement stage. The six-dimensional force sensor is installed between the outlet coupling flange and the magnetic attraction device to detect torque signals in real time during the assembly process. The compliant device works in conjunction with the power transmission device to provide the entire assembly process with comprehensive compliant capabilities including variable stiffness constraint, dynamic contact buffering, and nonlinear mechanical disturbance suppression, thereby improving the assembly stability of the system under bolt tilt, track vibration, or engagement deviation.

[0010] As a further technical solution, the magnetic suction device includes a fixed base, a magnetic sleeve, and an annular magnet; the fixed base is detachably connected to a six-dimensional force sensor by screws; the magnetic sleeve is located at the lower end of the fixed base and contains an annular magnet arranged in the circumferential direction to form a magnetic field gradient and provide passive attitude guidance before the nut enters the thread inlet, so that the nut can be naturally aligned and enter the initial engagement area, thereby improving the initial alignment accuracy and reducing the assembly failure rate.

[0011] As a further technical solution, the propulsion device includes a drive module and a sliding module; the drive module includes a DC brushless geared motor, a motor mounting plate, a slide rail mounting base, a slide rail, a slider, a stop block, and a bent plate; the DC brushless geared motor is fixedly connected to the mounting base of the nut assembly mechanism via the motor mounting plate, providing a stable linear driving force for the propulsion device; the slide rail mounting base is located on the right side of the DC brushless geared motor and is fixedly connected to it by bolts to form a sliding guide support structure; the slide rail is fixedly connected to the slide rail mounting base by screws, and the slider and the slide rail are engaged by a snap-fit ​​mechanism to achieve smooth sliding along the slide rail direction; the stop blocks are respectively fixed at both ends of the slide rail to limit the movement stroke of the slider and prevent it from falling off; the bent plate is fixedly connected to the slider by screws, and the output shaft of the DC brushless geared motor is connected to the bent plate to drive the bent plate along the slide rail direction. The mechanism performs reciprocating linear motion. The sliding module includes a push plate, a flange seat, a linear bearing, a sliding bearing, and a circular plate. One end of the push plate abuts against the lower end face of the curved plate, and the other end is fixedly connected to the flange seat by bolts, which is used to transmit the linear propulsion force of the drive module to the flange seat. The lower end of the flange seat is connected to the mounting holes on the circular plate through four support columns to form a stable rigid support. The inner ring of the sliding bearing is connected to the outer circle of the shaft end of the power transmission shaft by an interference fit. The outer ring is fixed by a set screw through a threaded hole on the circular plate to achieve coaxial constraint and reliable positioning of the power transmission component and the propulsion structure. During operation, the propulsion mechanism realizes torque and propulsion coupling control based on the dynamic relationship between the thread meshing resistance, the feedback of the six-dimensional force sensor, and the output torque of the power transmission device, so as to avoid jamming, stripping, or failure to engage due to excessive propulsion speed or insufficient torque.

[0012] As a further technical solution, the nut assembly mechanism can be used as a rail fastener assembly device on its own, or it can be integrated into the automated operation system of the rail work vehicle.

[0013] Additional aspects and advantages of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention.

[0014] The beneficial effects of this invention are as follows: 1. This invention integrates a binocular vision inspection system, a robotic arm, and an intelligent control algorithm, which can automatically identify the position of fasteners and complete the precise positioning and tightening of nuts, realizing full automation from identification to assembly, greatly improving assembly efficiency and accuracy, and reducing manual labor intensity.

[0015] 2. Through the combined compensation structure of the retractable universal connector and the compliant device, the axial deviation, posture error and uneven force during the assembly process can be effectively absorbed, the posture can be adaptively adjusted, the thread can be prevented from being mis-threaded or stuck, and the assembly process can be ensured to be smooth and reliable.

[0016] 3. The six-dimensional torque sensor enables real-time torque detection and adaptive adjustment, ensuring uniform and consistent nut preload; the mechanism adopts a modular design, is compact and easy to maintain, and can adapt to various sleeper structures and complex working conditions, exhibiting good versatility and stability. Attached Figure Description

[0017] Figure 1 This is an overall schematic diagram of an automated assembly mechanism for railway track fastener nuts according to an embodiment of the present invention.

[0018] Figure 2 This is a schematic diagram of the nut assembly mechanism and power transmission device in this invention.

[0019] Figure 3 This is an exploded structural diagram of the nut assembly mechanism in this invention.

[0020] Figure 4 This is a front view schematic diagram of the nut assembly mechanism and the visual inspection and recognition device in this invention.

[0021] Figure 5 This is a cross-sectional view of the nut assembly mechanism and visual inspection and recognition device of the present invention along section AA.

[0022] Figure 6 This is a schematic diagram of the propulsion device structure in this invention.

[0023] Figure 7 This is a front view schematic diagram of the propulsion device in this invention.

[0024] Figure 8 This is a cross-sectional view of the BB section of the propulsion device in this invention.

[0025] Figure 9 This is a schematic diagram of the structural composition of the connector in this invention.

[0026] Figure 10 This is a schematic diagram of the composition of the fastener in this invention.

[0027] Reference numerals: Base plate 1, robotic arm 2, power transmission device 3, connecting seat 4, vision inspection and recognition device 5, nut assembly mechanism 6, propulsion device 7, fastener 8, compliant device 61, fixing module 62, flexible module 63, magnetic suction device 64, drive module 71, sliding module 72, road stud 81, nut 82, servo motor 31, planetary reducer 32, rigid coupling 33, telescopic universal joint assembly 34, outer cylinder 341, inner sliding shaft 342, cylindrical surface 41, left side plate 43, right side plate 44, bolt hole 45, binocular camera 51, camera mounting plate 52, mounting seat 621, electric slip ring 622, power transmission shaft 623, rolling bearing 624, bearing seat 625, input end coupling flange 631, output end coupling flange 632, universal joint coupling 633, compression spring 634, Six-dimensional force sensor; 635, Fixing base; 641, Magnetic sleeve; 642, Ring magnet; 643, DC brushless geared motor; 711, Motor mounting plate; 712, Slide rail mounting base; 713, Slide rail; 714, Slider; 715, Stop block; 716, Bend plate; 717, Push plate; 721, Flange seat; 722, Linear bearing; 723, Sliding bearing; 724, Circular plate; 725; Upper cover plate; 6211, Bolt hole; 6212, Lower cover plate; 6213, Bolt hole; 6214, Bolt hole; 6215, Key; 6231, Outer ring; 6221, Inner ring; 6222, Threaded hole; 6223, Fixing base flange face; 6411, Threaded hole; 6412, Flange face; 6413, Threaded hole; 6414, End face; 6421, Output shaft; 7111, Support column; 7221, Mounting hole; 7251, Threaded hole; 7252. Detailed Implementation

[0028] The technical solution of this patent will be further described in detail below with reference to specific embodiments.

[0029] The embodiments of this patent are described in detail below. Examples of these embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain this patent, and should not be construed as limiting this patent.

[0030] In the description of this patent, it should be understood that the terms “center,” “upper,” “lower,” “front,” “back,” “left,” “right,” “vertical,” “horizontal,” “top,” “bottom,” “inner,” “outer,” “side,” and “between,” etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this patent and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this patent.

[0031] In the description of this patent, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "setting" should be interpreted broadly. For example, they can refer to a fixed connection or setting, a detachable connection or setting, or an integral connection or setting. Those skilled in the art can understand the specific meaning of the above terms in this patent according to the specific circumstances.

[0032] Please refer to the attached document. Figures 1-10 This invention discloses an automated assembly mechanism for railway track fastener nuts. This mechanism integrates visual recognition, intelligent control, mechanical execution, and torque feedback control functions, enabling automatic identification and gripping, precise positioning, flexible tightening, and adaptive torque control of track fastener nuts. It is suitable for various sleeper types and complex construction environments. The key feature is that the robotic arm 2 and the power transmission device 3 are vertically fixed to the base plate 1 by bolts. The nut assembly mechanism 6, the power transmission device 3, and the propulsion device 7 are constructed as a cross-domain coupled composite assembly system. At the structural level, this system forms an assembly link with rigid transmission, compliant adjustment, magnetic field centralization, power coupling, and visual guidance. At the control level, it constructs a five-modal information fusion mechanism of force, position, angle, torque, and vision. The system is used to address issues such as axial error, radial offset, angular tilt, and rail surface deformation in the track fastener 8. Under the condition of track spike 81 attitude offset, trajectory adjustment, misalignment absorption, assembly stability control and mechanical disturbance suppression are achieved; the nut assembly mechanism 6 is fixed to the end of the robotic arm 2 through the connecting seat 4, which is used to provide six-dimensional spatial positioning accuracy and vibration resistance under high load conditions; the propulsion device 7 is connected and fixed to the lower part of the mounting seat 621 through the motor mounting plate 712, so that the axial propulsion force and the thread engagement state generate real-time dynamic synchronization; the binocular camera 51 in the vision detection and recognition device 5 is mounted above the nut assembly mechanism 6 through the camera mounting plate 52 and kept parallel, which is used to acquire three-dimensional images of the track fastener area; the binocular vision data and the micro-contact force sensed by the six-dimensional force sensor 635 together constitute a dual closed-loop control system of spatial posture feedforward and mechanical state feedback, and the power transmission device 3 provides torque output to the nut under the action of the compliant mechanism to complete the assembly of nut 82.

[0033] The nut assembly mechanism 6 is fixed to the end of the robotic arm 2 via the connecting seat 4. The propulsion device 7 is connected and fixed to the lower part of the mounting seat 621 via the motor mounting plate 712. The binocular vision detection device 5 is installed above the nut assembly mechanism 6 and maintains a parallel viewing angle to acquire stereoscopic images of the fastener 8 area. The vision controller performs feature extraction and pose recognition on the image, calculates the deviation between the actual image and the desired image, and outputs an error signal to the motion controller. The robotic arm 2 adjusts its posture according to the control command to make the nut assembly mechanism 6 accurately aligned with the position directly above the road stud 81 to be installed. When the robotic arm 2 reaches the predetermined position, the servo motor 31 transmits torque through the planetary reducer 32 and the telescopic universal connection assembly 34 to realize the assembly of the nut 82. The retractable universal joint assembly 34 compensates for axis and position errors, ensuring stable transmission; the compliant device 61 absorbs assembly deviations and uneven force, achieving adaptive posture adjustment and avoiding thread mis-threading and jamming; the propulsion device 7 ensures stable transmission of propulsion force and reliable structural connection during assembly; the magnetic suction device 64 attracts and fixes the nut 82, and the six-dimensional force sensor 635 detects the assembly torque in real time and feeds it back to the control system, achieving adaptive adjustment of preload and ensuring consistent preload of the nut 82. After assembly, the robotic arm 2 moves to the next fastener position to continue operation.

[0034] The robotic arm 2 preferably adopts an Aobo six-degree-of-freedom robot and is driven by a servo motor. Its control system includes a main power supply, a computer power supply unit, a computer control module, an input / output board, a user connection port, control boards for each axis, and a servo drive unit, etc., to achieve high-precision positioning control of multiple degrees of freedom, and to complete the automatic identification, positioning, and assembly guidance of the nut 82 based on the visual recognition and control algorithm of the binocular camera 51. The robotic arm 2 is fixedly mounted on the base plate 1 by bolts. The cylindrical surface 41 of the connecting seat 4 is provided with several bolt holes 42 for connection with the end of the robotic arm 2. The left side plate 43 and the right side plate 44 of the connecting seat 4 are respectively provided with bolt holes 45, and are fixed to the left and right side plates of the mounting base 621 by bolts to achieve reliable structural installation and stable support. The binocular camera 51 in the vision inspection and recognition device 5 is fixed above the nut assembly mechanism 6 by the camera mounting plate 52. The camera mounting plate 52 is fixed to the lower cover plate 6213 of the mounting base 621 by bolts. The lower cover plate 6213 is provided with bolt holes 6215. The binocular camera 51 acquires a stereo image of the track fastener area and outputs spatial pose information for automatic guidance of nut assembly. The power transmission device 3 includes a servo motor 31, a planetary reducer 32, a rigid coupling 33, and a telescopic universal joint assembly 34. The servo motor 31 is fixedly mounted on the base plate 1 by bolts and coaxially connected to the planetary reducer 32 to achieve efficient power transmission and speed matching. The telescopic universal joint assembly 34 includes an outer cylinder 341, an inner sliding shaft 342, and an angular offset compensation unit. The inner sliding shaft 342 slides along the axial direction of the outer cylinder to compensate for the axial offset of the nut 82 and the road spike 81. The angular offset compensation unit adopts a universal joint structure to absorb the angular deviation of the road spike tilt. The power transmission device 3 monitors the output torque of the servo motor 31 and combines the radial force, axial force, and torque information collected by the six-dimensional force sensor 635 to determine the thread engagement depth and contact state, and adjusts the torque threshold and assembly control parameters in real time.

[0035] The nut assembly mechanism 6 includes a compliant device 61, which comprises a fixed module 62 and a flexible module 63. The fixed module 62 includes a mounting base 621, an electric slip ring 622, a power transmission shaft 623, a rolling bearing 624, and a bearing housing 625. The fixed module 62 reduces rotational runout through a bearing support structure, enabling the flexible module 63 to maintain a stable power transmission path under high load conditions. The outer ring 6221 of the electric slip ring 622 is fixedly connected to the bolt holes 6212 of the upper cover plate 6211 of the mounting base 621 by bolts, and the inner ring 6222 is fitted onto the power transmission shaft 623 and secured by set screws. The threaded hole 6223 is used for fixing, thereby ensuring that the power drive shaft 623 provides continuous rotational electrical signals and continuous transmission of electrical energy to the six-dimensional force sensor 635 when it rotates. The shaft end of the power drive shaft 623 is connected to the retractable universal joint assembly 34 via a key 6231 to form a torque transmission connection structure. The bearing housing 625 is fixed to the lower cover plate 6213 of the mounting base 621 by bolts. The lower cover plate 6213 has bolt holes 6214, and the rolling bearing 624 is installed in the bearing housing 625 to support the rotation of the power drive shaft 623 and reduce rotational friction, thereby ensuring the transmission. Stability and reliability; the flexible module 63 in the nut assembly mechanism 6 includes an input coupling flange 631, an output coupling flange 632, a universal joint coupling 633, a compression spring 634, and a six-dimensional force sensor 635; the universal joint coupling 633 is connected between the input coupling flange 631 and the output coupling flange 632, and is used to compensate for angular deviations within a certain range, ensuring continuous and stable power transmission, preventing jamming or wear caused by shaft misalignment, and providing low-frequency angular compensation capability for the flexible module 63; the compression spring 634 is set between the input coupling flange 631 and the output coupling flange Between 632, there is a nonlinear segmented stiffness characteristic, exhibiting low stiffness energy absorption characteristics in the initial stage of meshing and high stiffness anti-eccentric load capability in the stable thread engagement stage; the six-dimensional force sensor 635 is installed between the output end coupling flange 632 and the magnetic suction device 64 to detect the torque signal in real time during the assembly process, realizing torque feedback and compliance control; the compliance device 61 and the power transmission device 3 work together to give the entire assembly process a comprehensive compliance capability of variable stiffness constraint, dynamic contact buffer, and nonlinear mechanical disturbance suppression, thereby improving the assembly stability of the system under spike tilt, track vibration or meshing deviation.

[0036] The magnetic suction device 64 includes a fixed base 641, a magnetic sleeve 642, and an annular magnet 643. The flange face 6411 of the fixed base is detachably connected to the six-dimensional force sensor 635 through the threaded hole 6412, and its opposite flange face 6413 is connected to the magnetic sleeve 642 through the threaded hole 6414. The magnetic sleeve 642 is located at the lower end of the fixed base 641. The annular magnet 643 inside it forms a magnetic field gradient in a circumferential direction, providing passive guidance before the nut 82 enters the threaded inlet, so that the nut enters the initial engagement area in a natural and stable posture, thereby improving the initial alignment accuracy and reducing the assembly failure rate.

[0037] The propulsion device 7 includes a drive module 71 and a sliding module 72. The drive module 71 includes a DC brushless geared motor 711, a motor mounting plate 712, a slide rail mounting base 713, a slide rail 714, a slider 715, a stop block 716, and a bent plate 717. The DC brushless geared motor 711 is bolted to the mounting base 621 of the nut assembly mechanism 6 via the motor mounting plate 712 to provide a stable linear driving force for the propulsion device. The slide rail mounting base 713 is mounted on the right side of the DC brushless geared motor 711 and fixed with bolts to form a sliding guide. The sliding module 72 includes a support structure; the slide rail 714 is fixedly connected to the slide rail mounting base 713 by screws, and the slider 715 is connected to the slide rail 714 by a snap-fit ​​connection to achieve smooth sliding along the slide rail direction; the stop blocks 716 are fixed to both ends of the slide rail 714 to limit the movement stroke of the slider 715 and prevent it from falling off; the bent plate 717 is fixedly connected to the slider 715 by screws, and the output shaft 7111 of the DC brushless geared motor 711 is connected to the bent plate 717 to drive the bent plate to perform reciprocating linear motion along the slide rail direction; the sliding module 72 includes a push plate. 721, flange seat 722, linear bearing 723, sliding bearing 724, and circular plate 725. One end of the push plate 721 abuts against the lower end face of the bent plate 717, and the other end is fixed to the flange seat 722 by bolts, used to transmit the linear thrust of the drive module to the flange seat 722. The lower end of the flange seat 722 is connected to the mounting holes 7251 of the circular plate 725 by four support columns 7221, forming a stable rigid support. The inner ring of the sliding bearing 724 is interference-fitted with the outer circle of the power transmission shaft end, and the outer ring passes through the threaded hole 725 on the circular plate 725. 2. Set screws are used for fixing to achieve coaxial constraint and reliable positioning of the power transmission components and the propulsion structure, ensuring the axial propulsion accuracy and torque transmission stability during the assembly of nut 82; During operation, the propulsion device 7 realizes torque and propulsion coupling control based on the dynamic relationship between the thread meshing resistance, the feedback of the six-dimensional force sensor 635 and the output torque of the power transmission device 3, that is, it automatically adjusts the propulsion speed according to the torque change, so that the thread meshing has dynamic following ability and avoids jamming, stripping or failure to screw in due to excessive propulsion speed or insufficient torque.

[0038] The nut assembly mechanism 6 can be used independently as a rail fastener assembly device, or it can be integrated into the automated construction system of the rail work vehicle.

[0039] This invention provides an automated assembly mechanism for railway track fastener nuts. The mechanism integrates a binocular vision device at the end of the nut assembly unit. Through the collaborative work of a robotic arm and the vision system, it achieves precise identification and automatic positioning of the fastener nut's position and orientation, eliminating the need for manual intervention. This automated assembly method reduces manual labor intensity, minimizes potential safety risks, and significantly improves work efficiency. The nut assembly mechanism can reliably complete the automatic tightening of fastener nuts, offering advantages such as reliable transmission, simple control, convenient maintenance, and consistent assembly quality, thereby achieving highly efficient automated assembly of railway track fastener nuts.

[0040] Obviously, those skilled in the art can make various modifications, improvements, and substitutions to this invention without departing from its spirit and essence. Any such modifications, improvements, and substitutions that fall within the protection scope of the claims of this invention and their equivalents should be included within the protection scope of this invention.

Claims

1. An automated assembly mechanism for railway track fastener nuts, characterized by: The device comprises a mechanical arm, a nut assembly mechanism, a bottom plate, a power transmission device, a propulsion device, a connecting seat and a visual detection and recognition device. The nut assembly mechanism is composed of a compliant device and a magnetic attraction device. The nut assembly mechanism comprises a mounting seat, an electric slip ring, a power transmission shaft, a rolling bearing, a bearing seat, an input end coupling flange, an output end coupling flange, a universal joint coupling, a compression spring, a six-dimensional force sensor, a fixing seat, a magnetic attraction sleeve and a ring-shaped magnet. The propulsion device comprises a DC brushless reduction motor, a motor mounting plate, a slide rail mounting seat, a slide rail, a slide block, a stop block, a bent plate, a propulsion plate, a flange seat, a linear bearing, a sliding bearing and a circular plate. The mechanical arm and the power transmission device are both vertically installed on the bottom plate. The nut assembly mechanism, the power transmission device and the propulsion device constitute a cross-domain coupled composite assembly system, which forms a composite assembly system with rigid transmission, compliant adjustment, magnetic field centralization and visual guidance cooperation at the structural level. Based on the five-mode information fusion of force, position, angle, torque and vision, the trajectory is self-adaptive, misalignment is absorbed and disturbance is suppressed to adapt to the working conditions such as bolt axial error, radial offset, spike inclination and rail surface deformation. The nut assembly mechanism is fixed at the end of the mechanical arm through the connecting seat to provide six-dimensional spatial positioning and anti-vibration capability. The propulsion device is connected and fixed through the motor mounting plate and the lower end of the fixing seat to synchronize the axial propulsion force and the thread engagement state in real time. The visual detection and recognition device adopts a binocular camera and is installed above the nut assembly mechanism, parallel to the end thereof, to obtain a three-dimensional image of the rail fastener area and form a posture feedforward and mechanical feedback double closed-loop control with the six-dimensional force sensor. The power transmission device provides torque output to the nut under the action of the compliant mechanism to complete the assembly of the nut.

2. An automated assembly mechanism for railway track fastener nuts as claimed in claim 1, wherein: The mechanical arm is preferably a Zhibo six-degree-of-freedom robot and is driven by a servo motor; the control system comprises a main power supply, a computer power supply unit, a computer control module, an input / output board, a user connection port, an axis control board and a servo drive unit, for realizing high-precision positioning control of multiple degrees of freedom, and automatic identification, positioning and assembly guidance of the nut based on binocular vision recognition and control algorithm; the mechanical arm is fixedly installed on the bottom plate by bolts; the cylindrical surface of the connecting seat is provided with a plurality of bolt holes, and the connecting seat is reliably connected with the end of the mechanical arm through bolts, and the left and right sides of the connecting seat are respectively provided with bolt holes, which are connected with the two sides of the mounting seat by bolts to realize stable support; the vision system adopts a binocular camera, which is fixedly installed on the mounting seat and used for collecting stereoscopic images of the track fastener area and outputting spatial pose information; the power transmission device comprises a servo motor, a planetary reducer, a rigid coupling and a telescopic universal joint assembly; the servo motor is fixedly installed on the bottom plate and coaxially connected with the planetary reducer, so as to realize efficient power transmission and speed matching; the telescopic universal joint assembly comprises an outer cylinder, a sliding inner shaft and an angular offset compensation unit, for compensating axial offset and spike inclination angle; the power transmission device judges the meshing depth and adjusts the torque threshold and assembly parameters in real time through the torque of the servo motor and the radial force, axial force and torque feedback of the six-dimensional force sensor.

3. An automated assembly mechanism for railway track fastener nuts as claimed in claim 1, wherein: A compliant device is arranged in the nut assembly mechanism; the compliant device comprises a fixed module and a flexible module; the fixed module comprises a mounting seat, an electric slip ring, a power transmission shaft, a bearing seat and a rolling bearing; the fixed module reduces rotational runout through a bearing support structure, so that the compliant module can still maintain a stable power transmission path under high load conditions; the electric slip ring is fixedly installed on the mounting seat, and its output end is connected with the power transmission shaft, for realizing continuous transmission of electrical signals and electrical energy during rotation; the bearing seat is fixedly connected to the lower end of the mounting seat by bolts, and the rolling bearing is installed in the bearing seat, for supporting the rotation of the power transmission shaft and reducing rotational friction, thereby ensuring the stability and reliability of transmission; the flexible module in the nut assembly mechanism comprises an input end coupling flange, an output end coupling flange, a universal joint coupling, a compression spring and a six-dimensional force sensor; the universal joint coupling is used to compensate for angular deviation and avoid jamming caused by axis misalignment, and provides low-frequency angular compensation capability for the flexible module; the compression spring has a nonlinear segmented stiffness characteristic, presents low stiffness energy absorption characteristics at the initial stage of engagement, and presents high stiffness anti-bias load capacity at the stable stage of thread engagement; the six-dimensional force sensor is installed between the output end coupling flange and the magnetic attraction device, for detecting torque signals in real time during assembly; the compliant device and the power transmission device jointly act, so that the entire assembly process has comprehensive compliant capabilities of variable stiffness constraint, dynamic contact buffering and nonlinear mechanics disturbance suppression, thereby improving the assembly stability of the system under bolt inclination, track vibration or engagement deviation.

4. An automated assembly mechanism for railway track fastener nuts as claimed in claim 1, wherein: The magnetic attraction device comprises a fixed seat, a magnetic attraction sleeve and a ring-shaped magnet; the fixed seat is detachably connected with the six-dimensional force sensor through a screw; the magnetic attraction sleeve is arranged at the lower end of the fixed seat and internally arranged with the ring-shaped magnet arranged along the circumferential direction, used for forming a magnetic field gradient and providing a passive posture guide before the nut enters the threaded entrance, so that the nut is naturally centered and enters the initial engagement area, thereby improving the initial alignment accuracy and reducing the assembly failure rate.

5. An automated assembly mechanism for railway track fastener nuts as claimed in claim 1, wherein: The advancing device comprises a driving module and a sliding module; the driving module comprises a direct-current brushless reduction motor, a motor mounting plate, a sliding rail mounting seat, a sliding rail, a sliding block, a stop block and a bent plate; the direct-current brushless reduction motor is fixedly connected with the mounting seat of the nut assembly mechanism through the motor mounting plate, used for providing stable linear driving force for the advancing device; the sliding rail mounting seat is arranged at the right side of the direct-current brushless reduction motor and fixedly connected therewith through bolts, so as to form a sliding guide support structure; the sliding rail is fixedly connected with the sliding rail mounting seat through screws, and the sliding block and the sliding rail are buckled to realize smooth sliding along the sliding rail; the stop blocks are respectively fixed at both ends of the sliding rail, used for limiting the movement stroke of the sliding block and preventing it from falling off; the bent plate is fixedly connected on the sliding block through screws, and the output shaft of the direct-current brushless reduction motor is connected with the bent plate, used for driving the bent plate to make reciprocating linear motion along the sliding rail; the sliding module comprises a pushing plate, a flange seat, a linear bearing, a sliding bearing and a circular plate; one end of the pushing plate abuts against the lower end surface of the bent plate, and the other end is fixedly connected with the flange seat through bolts, used for transmitting the linear advancing force of the driving module to the flange seat; the lower end of the flange seat is connected with the mounting holes on the circular plate through four support columns, so as to form stable rigid support; the inner ring of the sliding bearing is connected with the outer circle of the shaft end of the power transmission shaft through interference fit, and the outer ring is fixed by a jackscrew through the threaded holes on the circular plate, so as to realize coaxial constraint and reliable positioning of the power transmission component and the advancing structure; during the working process of the advancing mechanism, the dynamic relationship among the threaded engagement resistance, the six-dimensional force sensor feedback and the output torque of the power transmission device is realized, so as to realize torque and advancing coupling control, and avoid the sticking, slipping or rotation failure caused by too fast advancing speed or insufficient torque.

6. An automated assembly mechanism for railway track fastener nuts as claimed in any one of claims 1 to 5, wherein: The nut assembly mechanism can be used as a track fastener assembly device alone, or can be integrated into the track operation vehicle automatic operation system.

Images