A side beam welding robot

Abstract

The present invention relates to the technical field of welding equipment, and discloses a side beam welding robot, which includes a tooling for clamping a workpiece, casters, two welding guns arranged relatively on both sides of the casters, a mechanical arm driving the welding guns to walk along a predetermined U-shaped path, a pressure sensor arranged at the mobile end of the mechanical arm and a screw mechanism for driving the two welding guns to move closer to or away from each other, a proximity sensor arranged on the casters, and a control unit. The present invention has the following advantages and effects: based on the U-shaped walking path preset at the mobile end of the mechanical arm, a weld tracking adjustment structure is formed by a pressure sensor and a proximity sensor, a controller, a mechanical arm and a screw mechanism, and the walking path of the welding gun is fine-tuned. While taking into account high efficiency, large welding deviations can be avoided, thereby ensuring the welding quality of the equipment to the workpiece.

Description

Technical Field

[0001] The present invention relates to the technical field of welding equipment, and particularly relates to a side crossbeam welding robot. Background Art

[0002] A vehicle frame generally consists of longitudinal beams and crossbeams. Its forms are mainly of two types: side beam type and center beam type. The side beam type vehicle frame consists of two longitudinal beams located on both sides and several crossbeams, and the longitudinal beams and crossbeams are connected into a rigid framework by riveting or welding. The crossbeams not only ensure the torsional stiffness of the vehicle frame and bear longitudinal loads, but also support the main components on the vehicle. Usually, a truck has 5 - 6 crossbeams, and sometimes there are more. The structural feature of the side beam type vehicle frame is that it is convenient for installing a cab, a carriage, and some special equipment and arranging other assemblies, which is beneficial to modifying and varying vehicles and developing multi - variety vehicles. Therefore, it is widely used in freight trucks and most special vehicles. Among them, the side crossbeam of the vehicle frame is generally set in a U - shaped structure, and its bent part is usually set in an inverted bevel or inverted rounded - corner shape.

[0003] With the rapid development of modern industrial technology, automated welding technology has been widely used in various fields. In the traditional side crossbeam welding field, usually, a U - shaped workpiece one and two U - shaped workpieces two are taken. The workpieces two respectively abut against the inner and outer side walls of the workpiece one, and then a special machine is used to weld the two U - shaped weld seams in sequence. However, due to reasons such as workpiece size errors, fixture positioning errors, thermal deformation during workpiece welding, and welding torch movement trajectory errors, the robotic arm driving the welding torch to move will not automatically adjust the path. Therefore, during welding, the relative position between the weld seam and the welding torch will deviate, resulting in defects such as missed welding and undercut, leading to a sharp decline in welding quality, which needs to be improved. Summary of the Invention

[0004] The purpose of the present invention is to provide a side crossbeam welding robot, which solves the problem that the robotic arm of the existing welding equipment cannot automatically adjust the path according to the weld deviation, and achieves the purpose of improving welding quality.

[0005] The above - mentioned technical purpose of the present invention is achieved through the following technical solutions:

[0006] A side beam welding robot comprises a tooling for clamping a workpiece, a caster, two welding guns arranged relatively on both sides of the caster, a mechanical arm for driving the welding guns to move along a predetermined U-shaped path, a pressure sensor arranged at the moving end of the mechanical arm and a screw mechanism for driving the two welding guns to move closer to or farther from each other, a proximity sensor arranged on the caster, and a control unit; the detection end of the pressure sensor is connected to the caster and is used to send the detected pressure signal to the control unit, the proximity sensor is used to sense the positions of two welds on the tooling and send two sensing signals to the control unit, the control unit is used to compare the pressure signal and the sensing signal, and control the movement of the mechanical arm and the screw mechanism so that the caster contacts the center point between the two welds of the workpiece on the tooling and the welding head of the welding gun faces the weld.

[0007] By adopting the above technical solution, during actual welding, each structure is adjusted to a preset value, and then the caster moves toward the end of the workpiece in advance until the pressure sensor feeds back the pressure; at this time, due to the processing error of the workpiece, the workpiece tends to be straight in the horizontal direction, but there may be slight undulations in the vertical direction of the workpiece, so the pressure sensor, the control unit and the robot arm are used to maintain a suitable pre-pressure between the caster and the welding surface of the workpiece, that is, the height difference between the weld and the welding gun tends to be consistent; at the same time, the proximity sensor uses the change of the electrical signal generated in the metal body of the detection object caused by electromagnetic induction to capture the position of the weld, and then the control unit analyzes the induction signals corresponding to the two welds, and compares the analyzed positions of the two welds with the spacing of the welding gun on the screw mechanism. The comparison is performed to control the movement of the mobile end of the robot arm, and the two welding guns are driven to move closer or farther away from each other through the screw mechanism until the difference in the distance between the two welds and the casters approaches zero, and the distance between the welding points of the welding guns is equal to the distance between the two welds, so that the casters are finally moved to the center points of the two welds on the welding surface of the workpiece on the tooling, and the welding head of the welding gun is always facing the weld so as to perform double weld welding at the same time; by adopting the above structure, on the premise of a U-shaped walking path preset by the mobile end of the robot arm, a weld tracking adjustment structure is composed of a pressure sensor and a proximity sensor, a control unit, a robot arm and a screw mechanism to fine-tune the walking path of the welding gun, which can avoid large welding deviations while taking into account high efficiency, thereby ensuring the welding quality of the equipment to the workpiece.

[0008] The present invention is further configured as follows: the control unit includes a controller, a magnetic scale fixed to the moving end of the robotic arm, and a reader connected to the caster, the magnetic scale is used to measure the position of the reader and send a position signal to the controller, the signal receiving end of the controller is electrically connected to the pressure sensor and the proximity sensor, and the control output end is electrically connected to the robotic arm and the screw mechanism.

[0009] By adopting the above technical solution, during adjustment, the pressure sensor transmits the pressure signal detected by the detection end in contact with the elastic member to the controller, and the controller compares the pressure signal with the pressure threshold and calculates the travel distance of the reading head when the pressure threshold is reached. The controller then sends the calculation result to the robotic arm, and the mobile end of the robotic arm moves until the reading head moves to the preset position of the magnetic scale, so that a constant force can be maintained between the mobile end of the robotic arm and the workpiece, so that the welding head of the welding gun is always facing the weld; in addition, the controller also plays the role of receiving the induction signal of the proximity sensor and controlling the action of the lead screw mechanism.

[0010] The present invention is further configured as follows: there is a travel distance between the caster and the welding gun, a retractable elastic member is provided between the caster and the moving end of the robot arm, and the retractable portion of the elastic member abuts against the detection head of the pressure sensor.

[0011] By adopting the above technical solution, the caster serves as the main structure for realizing weld detection, and it needs to move slightly ahead of the welding gun. When the welding surface of the workpiece fluctuates, the caster will fluctuate accordingly and drive the elastic part to expand and contract, which will not directly cause the welding gun to shake due to the fluctuation of the welding surface, and can give the control unit time to feedback.

[0012] The present invention is further configured as follows: the elastic member includes a mounting plate that abuts against the detection end of the pressure sensor, a first guide bearing fixed between the moving end of the robotic arm and the mounting plate, an adjustment plate fixed on the caster, a second guide bearing and a compression spring fixed between the mounting plate and the adjustment plate, and the reader is arranged on the mounting plate.

[0013] By adopting the above technical scheme, the impact of the pressure sensor on the pressure sensor faced by the concave-convex welding is buffered by the compression spring, and the magnetic scale can directly measure the current position of the mobile end of the robot arm, which can eliminate the error caused by the slight expansion and contraction of the compression spring, so as to directly realize the feedback of the mobile end of the robot arm. If this method is not adopted, the state end feedback method must be used, and then the output feedback amount needs to be estimated by using the state feedback amount, which is more complicated; in addition, the second guide bearing is used to limit the expansion and contraction direction of the compression spring, and the first guide bearing is used to limit the moving direction of the mounting plate, thereby constraining the redundant degrees of freedom of movement of the mounting plate, that is, eliminating the lateral force pressing on the pressure sensor. The existence of this lateral force will seriously affect the life and accuracy of the pressure sensor. On the other hand, the existence of the mounting plate also reduces the impact damage to the pressure sensor when the robot arm is changed from the free feeding state to the fitting state, thereby protecting the pressure sensor.

[0014] The present invention is further configured as follows: the screw mechanism includes a support plate arranged on the movable end of the robotic arm, a slide rail and a screw motor arranged on the support plate, and two transmission nuts slidably connected to the slide rail. The screw shaft of the screw motor is configured as a bidirectional screw, and the two transmission nuts are respectively threadedly connected to the two sections of threads on the bidirectional screw, and the welding gun is arranged on the transmission nut.

[0015] By adopting the above technical solution, the screw drive has the advantages of good self-locking and small starting torque. Under the premise of keeping the midpoint position between the two transmission nuts unchanged, the screw motor can drive the two welding guns to move at an equal distance to achieve horizontal transfer of the welding point.

[0016] The present invention is further configured as follows: the robotic arm includes a rodless cylinder, a frame, a Z-axis motor, at least two groups of support arms and an X-axis motor, a steering motor and a leveling motor connected in sequence along the power output direction; the slider of the rodless cylinder is fixed to the frame and is used to drive the frame to move along the X-axis; one end of the support arm is fixed to the X-axis motor, and the other end is rotatably connected to the Z-axis motor and the adjacent X-axis motor; the steering motor is rotatably connected to one of the X-axis motors and is perpendicular to the output shaft of the X-axis motor; the leveling motor is rotatably connected to the steering motor and is perpendicular to the output shaft of the steering motor.

[0017] By adopting the above technical solution, the Z-axis motor mainly makes these arms form a connecting rod structure through a revolute connection, and drives the connecting rod structure to move on the YZ plane. At the same time, the frame is driven to move along the X-axis by setting a rodless cylinder, so as to realize the movement of the welding gun in any three-dimensional direction within the predetermined space; at the same time, the welding gun is driven to rotate along the YZ axis by setting a steering motor, and the welding gun is driven to rotate around the Z axis with the assistance of the Z-axis motor, so that the two welding guns can adapt to the change of movement direction at the bend of the weld; in addition, the welding gun is driven to rotate along the axis parallel to the XY plane by the leveling motor, so that the processing end of the welding gun can be on the same XY plane to avoid welding leaks.

[0018] The present invention is further configured as follows: the tooling includes a mounting base, a pair of U-shaped rods fixed on the mounting base, a plurality of fixing seats arranged along the length direction of the U-shaped rods, a fixing pressure plate arranged on the fixing seats, and a fixing bolt threadedly connected to the fixing seats; when in use, the end of the workpiece is overlapped on the mounting base and can be slid away along the gap between the two U-shaped rods, the fixing pressure plate abuts against the top surface of the workpiece, and the fixing bolt tightly abuts against the side wall of the workpiece.

[0019] By adopting the above technical solution, during installation, the tooling can be arranged horizontally, workpiece one moves down through the gap between the fixed pressure plates, and its end is overlapped on the top surface of the mounting base, and the two workpieces two move up through the gap between the U-shaped rod and workpiece one respectively, and abut against the bottom surfaces of the corresponding fixed pressure plates, and then one of the workpieces one and two is pressed toward the clamp on the U-shaped rod on one side, and the fixing bolt on the U-shaped rod on the other side is rotated so that the fixing bolt is tightly abutted against the side wall of workpiece two; during disassembly, the fixing bolt on one side of the U-shaped rod is loosened, and then the workpiece is moved horizontally to separate it from the mounting base, and then the workpiece is removed from between the U-shaped rods.

[0020] The present invention is further configured as follows: it also includes a rotating mechanism that drives the tooling to rotate around the X-axis, the rotating mechanism includes a pair of vertical frames, a mounting frame rotatably connected between the vertical frames, a driven wheel arranged on the mounting frame, a rotating motor, a driving wheel rotatably connected to the rotating motor, and a transmission belt sleeved outside the driving wheel and the driven wheel, and the tooling is detachably connected to the mounting frame.

[0021] By adopting the above technical solution, the tooling is driven to rotate around the X-axis through the belt transmission structure. Without designing additional programs for the robot arm, the angle between the welding surface of the workpiece and the welding gun can be adjusted quickly, which is convenient for the control unit to detect and control.

[0022] The present invention is further configured as follows: a hanger is provided on the tooling, a positioning frame is provided on the mounting frame and is connected to the outside of the tooling along the axial direction of the driven wheel, at least two short chains and hooks fixed to the free ends of the short chains are provided on the positioning frame, the hooks are inserted into the hanger and force the short chains to be straightened.

[0023] By adopting the above technical solution, when loading, the tooling clamped with the workpiece is located at a predetermined position, the hook is first hooked on the hanging seat, and then the hook is driven to move and lift the tooling through the rotating mechanism, which can reduce the time of manually moving the tooling to the rotating mechanism. When unloading, the reverse operation can be performed, which is conducive to improving the efficiency of loading and unloading.

[0024] The present invention is further configured as follows: the mounting frame is provided with a positioning block and is threadedly connected with three locking bolts; the mounting base frame is provided with a positioning hole embedded with the positioning block and three locking screw holes threadedly connected with the locking bolts.

[0025] By adopting the above technical solution, the preliminary positioning of the tooling on the mounting frame is first achieved by engaging the positioning block with the positioning hole, and then the tooling is fixed by cooperating with the locking bolt and the locking screw hole, which is easy and quick to operate.

[0026] The beneficial effect of the present invention is that, based on the preset U-shaped walking path of the moving end of the robotic arm, a weld tracking adjustment structure is composed of a pressure sensor and a proximity sensor, a controller, a robotic arm and a screw mechanism to fine-tune the walking path of the welding gun. While taking into account high efficiency, large welding deviations can be avoided, thereby ensuring the welding quality of the equipment to the workpiece. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0028] Figure 1 It is a schematic structural diagram of the side beam welding robot of the present invention when welding a cross section of a workpiece.

[0029] Figure 2 It is a structural schematic diagram of the side beam welding robot of the present invention when welding a vertical section of a workpiece.

[0030] Figure 3 It is a structural schematic diagram of the workpiece clamping device of the present invention.

[0031] Figure 4 It is a structural schematic diagram of the tooling of the present invention.

[0032] Figure 5 It is a schematic structural diagram of the mechanical arm of the present invention.

[0033] Figure 6 It is a schematic diagram of the connection relationship between the welding gun, casters and screw mechanism of the present invention.

[0034] Figure 7 It is a schematic diagram of the connection relationship between the caster, the elastic member and the weld tracking adjustment device of the present invention.

[0035] In the figure, 1, workpiece clamping device; 11, positioning hole; 12, locking bolt; 13, positioning block; 14, locking screw hole; 2, tooling; 21, mounting base; 22, U-shaped rod; 23, fixed seat; 24, fixed pressure plate; 25, adjusting bolt; 26, fixing bolt; 27, strip groove; 28, hanging seat; 3, rotating mechanism; 31, stand; 32, mounting frame; 33, driven wheel; 34, rotating motor; 35, driving wheel; 36, transmission belt; 37, positioning frame; 38, short chain; 39, hook; 4, welding device; 5, mechanical arm; 51, rodless cylinder; 52, frame; 53 , Z-axis motor; 54, support arm; 55, X-axis motor; 56, steering motor; 57, leveling motor; 58, moving arm; 59, slide; 6, casters; 7, welding gun; 8, weld seam tracking adjustment device; 81, pressure sensor; 82, screw mechanism; 821, support plate; 822, slide rail; 823, screw motor; 824, transmission nut; 83, proximity sensor; 84, control unit; 841, controller; 842, magnetic scale; 843, reading head; 9, elastic member; 91, mounting plate; 92, first guide bearing; 93, adjustment plate; 94, second guide bearing; 95, compression spring. DETAILED DESCRIPTION

[0036] The technical solution of the present invention will be clearly and completely described below in conjunction with specific embodiments. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0037] Reference Figure 1 and Figure 2 , is a side beam welding robot disclosed in the present invention, comprising a workpiece clamping device 1 for clamping a workpiece, a welding device 4 for welding two welds on a workpiece at the same time, and a weld tracking adjustment device 8. Among them, the workpiece clamping device 1 comprises a tool 2 for clamping a workpiece, a rotating mechanism 3 for driving the tool 2 to rotate around the X-axis, and the welding device 4 comprises a mechanical arm 5 with a preset U-shaped walking path, a caster 6 arranged at the moving end of the mechanical arm 5, and two welding guns 7 arranged on both sides of the caster 6. The weld tracking adjustment device 8 can be controlled by feedback of the pressure state and relative position state between the caster 6 and the weld, so that the mechanical arm 5 can automatically adjust the path according to the calculated weld deviation, so that the welding heads of the two welding guns 7 can be respectively oriented to the welds on both sides.

[0038] Reference Figure 3The rotating mechanism 3 includes a pair of vertical frames 31 arranged side by side along the X-axis direction, a mounting frame 32 rotatably connected between the vertical frames 31, a driven wheel 33 arranged on the mounting frame 32, a rotating motor 34, a driving wheel 35 rotatably connected to the rotating motor 34, and a transmission belt 36 sleeved outside the driving wheel 35 and the driven wheel 33. The tooling 2 is driven to rotate around the X-axis by the belt transmission structure, and the angle between the workpiece welding surface and the welding gun 7 can be quickly adjusted to 90° without designing additional programs for the robot arm 5, so that the weld seam tracking adjustment device 8 can track and adjust it.

[0039] Reference Figure 4 The tooling 2 includes a mounting frame 21, a pair of U-shaped rods 22 fixed on the mounting frame 21, six fixing seats 23 arranged along the length direction of the U-shaped rods 22, a fixing pressure plate 24 arranged on the fixing seat 23, and an adjusting bolt 25 and a fixing bolt 26 threadedly connected to the fixing seat 23. Among them, a strip groove 27 is provided on the fixing pressure plate 24, and the adjusting bolt 25 is passed through the strip groove 27 and abuts against the end face of the fixing pressure plate 24, so that the fixing pressure plate 24 abuts against the top surface of the workpiece. The axis of the adjusting bolt 25 and the axis of the fixing bolt 26 are perpendicular to the length direction of the corresponding workpiece fixing section. When in use, the fixing bolt 26 can rotate on the fixing seat 23 and tightly abut against the circumferential side wall of the workpiece. When disassembling, the end of the workpiece overlaps the mounting frame 21 and can slide and detach along the U-shaped gap between the two U-shaped rods 22.

[0040] Reference Figure 3 and Figure 4 In addition, in order to facilitate loading and unloading of the tooling 2, a hanging seat 28 is provided on the tooling 2, and a positioning frame 37 is provided on the mounting frame 32, which is connected to the outside of the tooling 2 along the axial direction of the driven wheel 33. The positioning frame 37 is provided with two short chains 38 and a hook 39 fixed to the free end of the short chain 38. The hook 39 is inserted into the hanging seat 28 and forces the short chain 38 to be straightened. At the same time, a positioning block 13 (refer to Figure 2 ), and is threadedly connected with three locking bolts 12, and the mounting base 21 is provided with a positioning hole 11 embedded with the positioning block 13, and three locking screw holes 14 threadedly connected with the locking bolts 12.

[0041] When loading, the tool 2 clamped with the workpiece is located at a predetermined position, the hook 39 is first hooked on the hanger 28, and then the hook 39 is driven by the rotating mechanism 3 to move and lift the tool 2, which can reduce the time of manually moving the tool 2 to the rotating mechanism 3. Then the mounting base 21 is abutted against the mounting frame 32, and the initial positioning of the tool 2 on the mounting frame 32 is achieved by the positioning block 13 and the positioning hole 11, and then the locking bolt 12 cooperates with the locking screw hole 14 to fix the tool 2, which is simple and quick to operate. When unloading, the reverse operation can be performed, which is conducive to improving the efficiency of unloading and unloading.

[0042] Reference Figure 5 The robot arm 5 includes a rodless cylinder 51, a frame 52, a Z-axis motor 53, two groups of arms 54 and an X-axis motor 55, a steering motor 56 and a leveling motor 57 which are sequentially connected along the power output direction. The output shafts of these motors may be provided with a deceleration or speed regulation structure. The specific connection method is that the rodless cylinder 51 is set on a slide 59, and the slider of the rodless cylinder 51 is fixed on the frame 52 which is slidably connected to the slide 59, and is used to drive the frame 52 to reciprocate along the X-axis; the Z-axis motor 53 is fixed on the frame 52, and its output shaft is fixed to the upper end of the first arm 54 to drive the first arm 54 to rotate along the Z-axis; the first X-axis motor 55 is fixed to the lower end of the first arm 54, and its output shaft is fixed to one end of the second arm 54 to drive the other end of the second arm 54 The second arm 54 is a second arm 54, and the output shaft of the second arm 54 is fixed to the steering motor 56, and is perpendicular to the output shaft of the steering motor 56, so as to drive the steering motor 56 to rotate around the X-axis; finally, the leveling motor 57 is fixed to the output shaft of the steering motor 56, so that the leveling motor 57 rotates around the axis of the steering motor 56, and the output shaft of the leveling motor 57 is perpendicular to the output shaft of the steering motor 56, and is fixed with a moving arm 58 as a moving end.

[0043] The Z-axis motor 53 is mainly used to connect these arms 54 to form a connecting rod structure through a revolute pair, and drives the connecting rod structure to move on the YZ plane, and drives the frame 52 to move along the X axis by setting the rodless cylinder 51, so as to realize the movement of the welding gun 7 in any three-dimensional direction within the predetermined space. At the same time, the steering motor 56 is set to drive the welding gun 7 to rotate along the YZ axis, and the Z-axis motor 53 is used to drive the welding gun 7 to rotate around the Z axis, so that the two welding guns 7 can adapt to the change of movement direction at the bend of the weld. In addition, the leveling motor 57 drives the welding gun 7 to rotate along the axis parallel to the XY plane, so that the processing end of the welding gun 7 can be on the same XY plane to avoid welding leaks.

[0044] Reference Figure 6 and Figure 7 The weld tracking adjustment device 8 includes a pressure sensor 81 arranged at the end of the movable arm 58, a screw mechanism 82 for driving the two welding guns 7 to move closer to or away from each other, a proximity sensor 83, and a control unit 84.

[0045] Reference Figure 6, wherein the lead screw mechanism 82 includes a support plate 821 disposed at the end of the movable arm 58, a slide rail 822 and a lead screw motor 823 disposed on the support plate 821, and two transmission nuts 824 slidably connected to the slide rail 822. The lead screw shaft of the lead screw motor 823 is configured as a bidirectional lead screw, and the two transmission nuts 824 are respectively threadedly connected to the two sections of threads on the bidirectional lead screw, and the welding gun 7 is disposed on the transmission nut 824. The lead screw drive has the advantages of good self-locking and small starting torque. On the premise of keeping the midpoint position between the two transmission nuts 824 unchanged, the lead screw motor 823 can drive the two welding guns 7 to move at an equal distance to achieve horizontal transfer of the welding point.

[0046] Reference Figure 7 In addition, there is a travel distance between the caster 6 and the welding gun 7, and a retractable elastic member 9 is provided between the caster 6 and the movable arm 58. The elastic member 9 includes a mounting plate 91 that abuts against the detection end of the pressure sensor 81, a first guide bearing 92 fixed between the movable arm 58 and the mounting plate 91, an adjustment plate 93 fixed on the caster 6, a second guide bearing 94 fixed between the mounting plate 91 and the adjustment plate 93, and a compression spring 95.

[0047] The caster 6 is the main structure for realizing weld detection, and it needs to move slightly ahead of the welding gun 7. When the welding surface of the workpiece rises and falls, the caster 6 rises and falls accordingly and drives the elastic part 9 to expand and contract. It will not directly cause the welding gun 7 to shake due to the fluctuation of the welding surface, and can give the control unit 84 time to feedback. The compression spring 95 is used to buffer the impact of the caster 6 on the pressure sensor 81 after the concave-convex welding, and the magnetic scale 842 can directly measure the current position of the mobile end of the robot 5, which can eliminate the error caused by the slight expansion and contraction of the compression spring 95, so as to directly realize the feedback of the mobile end of the robot 5. If this method is not adopted, the state end feedback method must be used, and then the output feedback amount needs to be estimated using the state feedback amount, which is more complicated; in addition, the second guide bearing 94 is used to limit the expansion and contraction direction of the compression spring 95, and the first guide bearing 92 is used to limit the moving direction of the mounting plate 91, thereby constraining the redundant degrees of freedom of movement of the mounting plate 91, that is, eliminating the lateral force pressing on the pressure sensor 81. The existence of this lateral force will seriously affect the life and accuracy of the pressure sensor 81. On the other hand, the existence of the mounting plate 91 also reduces the impact damage to the pressure sensor 81 when the robot 5 changes from the free feeding state to the fitting state, thereby protecting the pressure sensor 81.

[0048] Finally, the control unit 84 includes a controller 841, a magnetic scale 842 fixed to the moving arm 58, a reader 843 arranged on the mounting plate 91 and contacting the magnetic scale 842, a signal receiving end of the controller 841 is electrically connected to the pressure sensor 81 and the proximity sensor 83, and a control output end is electrically connected to the mechanical arm 5 and the lead screw motor 823. When in use, the magnetic scale 842 is used to measure the position of the reader 843 and send the position signal to the controller 841, the pressure sensor 81 is used to detect the pressure between the detection end and the mounting plate 91, and send the pressure signal to the control unit 84, the proximity sensor 83 is used to sense the position of the two welds on the tooling 2, and send the two sensing signals to the control unit 84, and the control unit 84 is used to compare the pressure signal and the sensing signal, and control the mechanical arm 5 and the lead screw mechanism 82 to move, so that the caster 6 contacts the center point between the two welds of the workpiece on the tooling 2, and the welding head of the welding gun 7 faces the weld.

[0049] During actual welding, each structure is adjusted to a preset value, and then the caster 6 moves toward the end of the workpiece in advance until the pressure sensor 81 feeds back the pressure. At this time, due to the processing error of the workpiece, the workpiece tends to be straight in the horizontal direction, but there may be slight undulations in the vertical direction. The pressure sensor 81 transmits the pressure signal to the controller 841, and the controller 841 compares the pressure signal with the pressure threshold and calculates the travel distance of the reader 843 when the pressure threshold is reached. Then the controller 841 sends the calculation result to the robot 5, and the robot 5 moves in a direction perpendicular to the welding surface of the workpiece until the reader 843 moves to the preset position of the magnetic scale 842, and finally maintains a suitable pre-pressure between the caster 6 and the welding surface of the workpiece, that is, the height difference between the weld and the welding gun 7 tends to be consistent. On this basis, the proximity sensor 83 uses the changes in electrical signals generated in the metal body of the detection object caused by electromagnetic induction to capture the position of the weld, and then the controller 841 analyzes the induction signals corresponding to the two welds, and compares the positions of the two welds obtained by analysis with the spacing between the two welding guns 7 on the screw mechanism 82, thereby controlling the robot arm 5 to move in a direction perpendicular to its travel direction, and driving the two welding guns 7 to move closer or farther away from each other through the screw mechanism 82 until the difference in the spacing between the two welds and the caster 6 approaches zero, and the spacing between the welding points of the welding gun 7 is equal to the spacing between the two welds, and finally the caster 6 moves to the center point of the two welds on the welding surface of the workpiece on the tooling 2, and the welding head of the welding gun 7 is always facing the weld.

[0050] The specific implementation principle of this embodiment is:

[0051] S1 The robot arm 5 drives the welding gun 7 to move to the initial processing point along a predetermined U-shaped route, and the tooling 2 loads the material;

[0052] The S2 caster 6 moves along the Y axis and contacts the welding surface of the workpiece near the end;

[0053] S3 The pressure sensor 81 detects a pressure signal, and the controller 841 compares the pressure signal with the pressure threshold, and calculates the travel distance of the reading head 843 when the pressure threshold is reached. The controller 841 then sends the calculation result to the robot arm 5, so that the robot arm 5 moves until the reading head 843 travels to the corresponding position of the magnetic scale 842;

[0054] S4 Then the proximity sensor 83 works, the proximity sensor 83 detects the horizontal distance between the welds on both sides and the caster 6, the controller 841 calculates the centering displacement of the caster 6, and the robot arm 5 drives the caster 6 to move to the center position between the two welds;

[0055] S5 At the same time, the controller 841 compares and calculates the distance between the two welding guns 7 and the distance between the welds on both sides, and the screw mechanism drives the two welding guns 7 to move synchronously to the calculated position so that the welding heads of the welding guns 7 face the welds;

[0056] S6 Finally, the welding gun 7 is started, and the robot arm 5 drives the welding gun 7 to move along the X-axis and Y-axis directions, and the rotating mechanism 3 drives the tooling 2 to rotate, so that the axis of the leveling motor 57 and the connecting line of the two processing ends of the welding gun 7 are parallel to the welding surface of the workpiece on the tooling 2;

[0057] During S7 welding, refer to S3-S5 to perform weld tracking and adjust the position of welding gun 7.

Claims

1. A side beam welding robot, characterized in that: The invention comprises a tool (2) for clamping a workpiece, a caster (6), two welding guns (7) arranged opposite to each other on both sides of the caster (6), a mechanical arm (5) for driving the welding guns (7) to move along a predetermined U-shaped path, a pressure sensor (81) arranged at the moving end of the mechanical arm (5) and a screw mechanism (82) for driving the two welding guns (7) to move closer to or farther from each other, a proximity sensor (83) arranged on the caster (6), and a control unit (84); the detection end of the pressure sensor (81) is connected to the caster (6) and is used to send a detected pressure signal to the control unit (84); the proximity sensor (83) is used to sense the positions of two welding seams on the tool (2) and to move the two welding seams closer to or farther from each other. The control unit (84) is used to compare the pressure signal and the sensing signal and control the movement of the mechanical arm (5) and the lead screw mechanism (82) so that the caster (6) contacts the center point between the two welds of the workpiece on the tooling (2) and the welding head of the welding gun (7) faces the weld. The control unit (84) includes a controller (841), a magnetic scale (842) fixed to the moving end of the mechanical arm (5), and a reader (843) connected to the caster (6). The magnetic scale (842) is used to measure the position of the reader (843) and send the position signal to the controller (841). The signal receiving end of the controller (841) The pressure sensor (81) and the proximity sensor (83) are electrically connected, and the control output end is electrically connected to the mechanical arm (5) and the screw mechanism (82). There is a travel distance between the caster (6) and the welding gun (7). A retractable elastic member (9) is arranged between the caster (6) and the moving end of the mechanical arm (5). The retractable part of the elastic member (9) abuts against the detection head of the pressure sensor (81). The elastic member (9) includes a mounting plate (91) abutting against the detection end of the pressure sensor (81), a first guide bearing (92) fixed between the moving end of the mechanical arm (5) and the mounting plate (91), an adjustment plate (93) fixed on the caster (6), and a retractable elastic member (9) fixed on the mounting plate (91). The second guide bearing (94) and the compression spring (95) are arranged between the mounting plate (91) and the adjustment plate (93); the reader (843) is arranged on the mounting plate (91); the robot arm (5) comprises a rodless cylinder (51), a frame (52), a Z-axis motor (53), at least two groups of support arms (54) and an X-axis motor (55), a steering motor (56) and a leveling motor (57) connected in sequence along the power output direction; the slider of the rodless cylinder (51) is fixed on the frame (52) and is used to drive the frame (52) to move along the X-axis; one end of the support arm (54) is fixed on the X-axis motor (55), and the other end is rotatably connected to the Z-axis motor (53) and the adjacent X-axis motor (55);The steering motor (56) is rotatably connected to one of the X-axis motors (55) and is perpendicular to the output shaft of the X-axis motor (55); the leveling motor (57) is rotatably connected to the steering motor (56) and is perpendicular to the output shaft of the steering motor (56); the tooling (2) comprises a mounting frame (21), a pair of U-shaped rods (22) fixed to the mounting frame (21), a plurality of fixing seats (23) arranged along the length direction of the U-shaped rods (22), and a fixing pressing sheet (24) arranged on the fixing seat (23). ), a fixing bolt (26) threadedly connected to the fixing seat (23); when in use, the end of the workpiece overlaps the mounting base (21) and can slide and detach along the gap between the two U-shaped rods (22), the fixed pressing plate (24) abuts against the top surface of the workpiece, and the fixing bolt (26) tightly abuts against the side wall of the workpiece, and also includes a rotating mechanism (3) for driving the tooling (2) to rotate around the X-axis, the rotating mechanism (3) includes a pair of vertical frames (31), a mounting frame (31) rotatably connected between the vertical frames (31) 32), a driven wheel (33) arranged on the mounting frame (32), a rotating motor (34), a driving wheel (35) rotatably connected to the rotating motor (34), and a transmission belt (36) sleeved outside the driving wheel (35) and the driven wheel (33); the tooling (2) is detachably connected to the mounting frame (32); a hanging seat (28) is arranged on the tooling (2); a positioning frame (37) is arranged on the mounting frame (32) and is connected to the outside of the tooling (2) along the axial direction of the driven wheel (33); the positioning frame (37) is provided with at least two short chains (38) and a hook (39) fixed to the free end of the short chain (38), the hook (39) is inserted into the hanging seat (28) and forces the short chain (38) to be straightened, the mounting frame (32) is provided with a positioning block (13) and is threadedly connected with three locking bolts (12), and the mounting base (21) is provided with a positioning hole (11) embedded with the positioning block (13) and three locking screw holes (14) threadedly connected with the locking bolts (12).

2. The side beam welding robot according to claim 1, characterized in that: The screw mechanism (82) comprises a support plate (821) arranged at the moving end of the mechanical arm (5), a slide rail (822) and a screw motor (823) arranged on the support plate (821), and two transmission nuts (824) slidably connected to the slide rail (822); the screw shaft of the screw motor (823) is configured as a bidirectional screw, and the two transmission nuts (824) are respectively threadedly connected to two sections of threads on the bidirectional screw; the welding gun (7) is arranged on the transmission nut (824).

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