Space curve welding device and welding method

Abstract

The spatial curve welding device of the present invention comprises a mechanical mechanism and a remote controller connected by communication, the mechanical mechanism comprises a frame, a gantry moving mechanism is arranged outside and above the frame, the second rotating mechanism and the locking mechanism are respectively fixedly connected to the two opposite side walls of the frame, the first rotating mechanism is also symmetrically arranged on the outer side wall of the frame, the extending direction of the rotating axis of the first rotating mechanism and the extending direction of the rotating axis of the second rotating mechanism are mutually orthogonal, and the motion output end of the gantry moving mechanism is installed with a welding mechanism. The spatial curve welding method of the present invention first models the workpiece and calculates the welding point posture data, and controls the workpiece to rotate to the specified position through the remote controller while controlling the movement of the welding gun to perform welding operations. The spatial curve welding device of the present invention uses three-dimensional software to plan the path of the weld instead of manual teaching, and controls the motor drive through the cascade PID control algorithm and pulse signal to improve the welding efficiency.

Description

Technical Field

[0001] The invention belongs to the technical field of welding, and relates to a space curve welding device. The invention also relates to a welding method using the device. Background Art

[0002] With the improvement of industrial automation technology and the rise of labor costs, production costs have increased accordingly. In order to reduce production costs, improve product quality and increase production efficiency, more and more welding robots are being used in welding production. Currently, most welding robots on the market are industrial articulated arm welding robots. In the welding robot system, the weld posture and welding gun posture have a great influence on the welding forming quality. In traditional spatial curve welding technology, the welding path needs manual teaching, and the welding gun is generally below the welding point. There is a dead point during welding, which affects the welding quality and welding efficiency. Summary of the invention

[0003] The purpose of the invention is to provide a space curve welding device, which has the characteristics of no welding dead point and high welding quality.

[0004] Another object of the present invention is to provide the above-mentioned spatial curve welding method, by planning the path of the weld in a three-dimensional model, controlling the mechanical mechanism according to the position output results of the weld point, thereby realizing the automated welding of the spatial curve of the workpiece and improving the welding quality and welding efficiency.

[0005] The technical solution adopted by the present invention is that the spatial curve welding device includes a mechanical mechanism and a remote controller connected by communication signals, the mechanical mechanism includes a frame, a gantry moving mechanism is arranged on the outside and above the frame, the second rotating mechanism and the locking mechanism are respectively fixedly connected to the opposite side walls of the frame, and the first rotating mechanism is also symmetrically arranged on the outer side wall of the frame, the extension direction of the rotation axis of the first rotating mechanism and the extension direction of the rotation axis of the second rotating mechanism are orthogonal to each other, and the motion output end of the gantry moving mechanism is installed with a welding mechanism, and the first rotating mechanism, the second rotating mechanism, the gantry moving mechanism, and the welding mechanism are respectively connected to the remote controller through communication signals.

[0006] The present invention is also characterized in that:

[0007] The first rotating mechanism includes a motor B, an output end of which is fixedly connected to a load-bearing shaft through a first motor flange, one end of which passes through a seat bearing and is fixedly connected to a bearing flange, the bearing flange is fixedly connected to the frame, the load-bearing shaft and the seat bearing are interference fit, the seat bearing is fixedly connected to a base, and the motor B is connected to a remote controller through a communication signal.

[0008] The second rotating mechanism includes a motor A fixedly connected to the frame, a second motor flange is keyed to the end of the output shaft of the motor A, and the motor A is connected to the remote controller via a communication signal.

[0009] The locking mechanism comprises a locking block fixedly connected to the inner side of the frame, a locking disc is connected to the side of the locking block facing away from the frame, and a flange bearing is fixedly connected to the side of the locking disc away from the locking block;

[0010] The locking disk is a disk structure with a threaded shaft fixedly connected to the center of the disk. A threaded through hole matching the threaded shaft is opened in the center of the locking block away from the frame. One end of the threaded shaft passes through the threaded through hole and is fixed to the frame. A flange bearing is fixedly connected to the other end of the threaded shaft and has an interference fit with the flange bearing. The center of the flange bearing is located on the extension line of the output shaft of motor A.

[0011] The gantry moving mechanism includes a gantry, on which a transverse moving mechanism is arranged, on which a longitudinal moving mechanism is slidably connected, the movement directions of the longitudinal moving mechanism and the transverse moving mechanism are orthogonal to each other, the movement output end of the longitudinal moving mechanism is fixedly connected to the welding mechanism, and the transverse moving mechanism and the longitudinal moving mechanism are located above the frame.

[0012] The gantry includes two parallel vertical frames, a horizontal beam is arranged between the tops of the two vertical frames, and the horizontal movement mechanism includes a motor C fixed to one end of the horizontal beam and a slide rail arranged on the horizontal beam. The slide rail is slidably connected to the longitudinal beam through a transmission mechanism, and the motor C is connected to the remote controller signal;

[0013] The longitudinal moving mechanism includes two longitudinal guide rails symmetrically arranged on the longitudinal beam. A motor D and a limit mechanism are respectively arranged near the two ends of the longitudinal beam. A slide is slidably installed between the two longitudinal guide rails. A transverse rack is arranged on the slide. A gear is arranged on the output shaft of motor D. The gear and rack are meshed for transmission. Motor D is connected to the remote controller signal.

[0014] The welding mechanism comprises a welding gun and a wire feeding mechanism. The welding gun is fixedly connected to the motion output end of the gantry moving mechanism, and the wire feeding mechanism is connected to the remote controller signal.

[0015] Another technical solution adopted by the present invention is a space curve welding method, which is specifically implemented according to the following steps:

[0016] Step 1, respectively fix the two ends of the fixture to the second motor flange and the flange bearing, then respectively install the two parts of the workpiece to be welded on the fixture, manually rotate the locking plate to control the fixture to align the welding surfaces of the workpiece to be welded, manually control each motor to zero, and set the position of the workpiece to be welded at this time as the initial position;

[0017] Step 2: 3D software modeling, path planning for the weld, extracting the coordinates of each discrete welding point on the weld trajectory at the initial position, taking each discrete welding point at the top as the target, and calculating the position output result of each discrete point of the weld;

[0018] Step 3, input the posture output result obtained in step 2 to the remote controller, and the remote controller sends a signal to control the first rotating mechanism, the second rotating mechanism, the gantry moving mechanism, and the welding mechanism to move jointly, and weld each discrete welding point of the weld until all discrete points of the weld are welded, and the spatial curve welding is completed.

[0019] Another technical solution of the present invention is also characterized in that:

[0020] The specific operation of step 2 is to model the workpiece according to the initial position state in the three-dimensional software, set the extension direction of the rotation axis of the first rotating mechanism to the Y axis, the extension direction of the rotation axis of the second rotating mechanism to the X axis, and the movement direction of the longitudinal moving mechanism to the Z axis, and establish a world coordinate system with the intersection of the X axis and the Y axis as the spatial origin, input the welding point spacing in the workpiece model, form a welding trajectory curve at the position where the two surfaces to be welded are butted, calculate and form a welding curve through all points at the butt position of the two surfaces to be welded, discretize the welding curve into points according to the welding point spacing requirements, and obtain the initial position coordinates of each discrete welding point;

[0021] With the welding point at the top as the goal, the motor expected angle angle_set(t) and actual angle angle(t) corresponding to each discrete welding point on the welding curve are calculated in sequence, as well as the position data of each discrete welding point on the X-axis and Z-axis, which are the position output results of each discrete point of the weld;

[0022] The expected angle angle_set(t) is the angle that the motor needs to rotate when each discrete welding point rotates from the X axis to the world coordinate XZ plane. The actual angle angle(t) is the angle that the motor has rotated at this time.

[0023] The initial coordinates of the Nth discrete welding point are (x0, y0, z0); the discrete welding point is rotated around the X-axis to the world coordinate XZ plane, at which the y0 coordinate is 0. Through homogeneous matrix calculation, the rotation angle α of the discrete welding point around the X-axis is obtained, which is the expected angle angle_set(t) of motor A. The actual angle angle(t) of the motor at the Nth discrete welding point is the angle that motor A has rotated at this time, that is, the expected angle of motor A at the N-1th discrete welding point; the discrete welding point and the two surfaces to be welded each form a prime line, and the angle between the two prime lines is angle θ. A plane is made through angle θ / 2, which is the angle bisector of the tangent plane of the two curved surfaces. A unit vector is made through angle θ / 2, and a polar unit vector coordinate system is established with the origin of the world coordinate system as the origin, and the angle between the angle bisector and the Z axis is obtained. That is the expected angle of motor B, and the actual angle of motor B is the expected angle of motor B at the N-1th point; a homogeneous matrix transformation is performed according to the obtained expected rotation angle, that is, the angle bisector plane is made parallel to the Z axis, and the final position of the discrete welding point after transformation is obtained (x1, 0, z1), where x1 and z1 are the position data of the welding gun on the X-axis and Z-axis.

[0024] Specifically, step 3 is to import the output results of the position and posture of each discrete point of the weld in step 2 into the reserved serial port of the single-chip data of the remote controller, and at the same time input the wire feeding speed required for welding into the reserved serial port, and the remote controller controls motor A, motor B, motor C, motor D, and the wire feeding mechanism to operate synchronously and continuously respectively;

[0025] The remote controller is connected to the ESC via bus communication. The ESC sends control signals to control the speed of motor A and motor B. Motor A and motor B are equipped with ESCs with different IDs. The remote controller performs closed-loop control on motor A and motor B through the cascade PID control algorithm. The first-loop controller is an angle controller, which calculates the desired speed speed_set(t):

[0026]

[0027] Where err1(t)=angle_set(t)-angle(t), kp1, ki1, kd1 are the three PID parameters of the first loop, angle_set(t) is the expected angle, and angle(t) is the actual angle;

[0028] The second loop controller is a speed controller, which calculates the control quantity u(t) and controls the rotation speed of motor A and motor B according to the control quantity u(t);

[0029]

[0030] Where err2(t)=speed_set(t)-speed(t), kp2, ki2, kd2 are the three PID parameters of the second loop, speed(t) is the actual speed, the actual speed is the working speed of the motor at time t, that is, the actual speed of the motor at the Nth welding point is the expected speed of the N-1th welding point;

[0031] The remote controller performs open-loop control of motors C and D through pulse signals, and uses hardware to open a direct data transmission path between RAM and I / O devices, that is, using DMA to generate M pulse signals. Among them, x 总 is the difference between the welding gun position data of two adjacent discrete welding points, x iis the displacement of the welding gun for each rotation of the motor output shaft, a is the subdivision number of the driver connected to the motor, and b is the motor step angle. After the DMA output is completed, the DMA transfer completion event in the hardware interrupt is triggered, an interrupt is generated, and the output of the pulse signal is stopped to achieve the number of control pulse signals, thereby controlling the displacement of the welding gun driven by C and motor D;

[0032] The remote controller controls the start and stop and speed of the wire feeding mechanism through pulse signals at the same time, realizing the start and stop of wire feeding and wire feeding speed control; the output pulse signal frequency calculation formula is: f is the pulse signal frequency, b is the motor step angle, and a is the subdivision number of the driver connected to the motor; the calculation formula for the wire feeding speed input value is: V = n*2π*r, V is the wire feeding speed, n is the motor speed, and r is the radius of the clamping wheel;

[0033] The remote controller controls motor A, motor B, motor C, motor D, and the wire feeding mechanism to perform synchronous and continuous motion respectively until the welding of all discrete welding points is completed, thereby completing the spatial curve welding work.

[0034] The beneficial effects of the present invention are:

[0035] 1. The spatial curve welding device of the present invention uses three-dimensional software to plan the path of the weld, replacing manual teaching and improving welding efficiency;

[0036] 2. The spatial curve welding device of the present invention cooperates with the two-degree-of-freedom rotating mechanism and the two-degree-of-freedom moving mechanism to ensure that each welding point on the welding line is always kept directly above the welding gun without changing its posture. The welding gun can work vertically to improve the welding quality and eliminate the welding dead point.

[0037] 3. The spatial curve welding device of the present invention drives the motor to control the rotation of the workpiece according to the posture output result, so that the welding gun can work into the angle bisector plane at the welding point, so that the welding gun can enter the maximum working space, effectively avoiding the interference of the workpiece itself with the welding gun;

[0038] 4. The space curve welding device of the present invention has a simple structure and a universal design, and is suitable for space curve welding between different workpieces to be welded;

[0039] 5. The spatial curve welding method of the present invention controls each motor through a cascade PID control algorithm and a pulse signal to respectively control the workpiece posture adjustment, welding gun position adjustment and welding wire feeding speed adjustment. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] Figure 1 It is a structural schematic diagram of the space curve welding device of the present invention;

[0041] Figure 2 The present invention Figure 1 A top view of

[0042] Figure 3 It is a structural schematic diagram of the first rotating mechanism in the space curve welding device of the present invention;

[0043] Figure 4 It is a structural schematic diagram of the locking mechanism in the space curve welding device of the present invention;

[0044] Figure 5 It is a structural schematic diagram of the gantry moving mechanism in the space curve welding device of the present invention;

[0045] Figure 6 It is a structural schematic diagram of the first rotation position of the frame in the space curve welding device of the present invention;

[0046] Figure 7 It is a structural schematic diagram of the second rotation position of the frame in the space curve welding device of the present invention;

[0047] Figure 8 It is a schematic structural diagram of the third rotation position of the frame in the space curve welding device of the present invention;

[0048] Fig. 9 It is a flowchart of the space curve welding method of the present invention;

[0049] Fig.10 It is a path planning logic block diagram of the space curve welding method of the present invention;

[0050] Fig.11 It is a control flow chart of the space curve welding method of the present invention;

[0051] Fig.12 It is an electric control logic block diagram of a remote controller in the space curve welding method of the present invention;

[0052] Fig.13 It is a schematic diagram of a welding curve of the space curve welding method of the present invention;

[0053] Fig.14 is a schematic diagram of the rotation angle α of the space curve welding method of the present invention;

[0054] Fig.15 It is a schematic diagram of the angle bisecting plane in the space curve welding method of the present invention.

[0055] In the figure, 1. first rotating mechanism, 1-1. motor B, 1-2. first motor flange, 1-3. load-bearing shaft, 1-4. seat bearing, 1-5. bearing flange;

[0056] 2. Locking mechanism, 2-1. Right frame, 2-2. Locking block, 2-3. Locking plate, 2-4. Flange bearing;

[0057] 3. Gantry moving mechanism, 3-1. Longitudinal moving mechanism, 3-2. Transverse moving mechanism, 3-3. Limiting mechanism, 3-4. Motor C, 3-5. Motor D;

[0058] 4. Welding mechanism, 4-1. Welding gun, 4-2. Wire feeding mechanism;

[0059] 5. Second rotating mechanism, 5-1. Motor A, 5-2. Second motor flange;

[0060] 6. Base, 7. Frame, 8. Fixture reserved position, 9. Welding curve, 10. Welding point. DETAILED DESCRIPTION

[0061] The present invention is described in detail below with reference to the accompanying drawings and specific embodiments.

[0062] The space curve welding device of the present invention has a structure as follows Figure 1 and Figure 2 As shown, it includes a mechanical mechanism and a remote controller connected by communication signals. The remote controller receives and stores data and transmits signals to control the motor drive. The mechanical mechanism includes a frame 7. A gantry moving mechanism 3 is arranged on the outside and above the frame 7. The second rotating mechanism 5 and the locking mechanism 2 are respectively fixed to the opposite side walls of the frame 7. The first rotating mechanism 1 is also symmetrically arranged on the outer side wall of the frame 7. The extension direction of the rotation axis of the first rotating mechanism 1 and the extension direction of the rotation axis of the second rotating mechanism 5 are orthogonal to each other. The motion output end of the gantry moving mechanism 3 is installed with a welding mechanism 4. The first rotating mechanism 1, the second rotating mechanism 5, the gantry moving mechanism 3, and the welding mechanism 4 are respectively connected to the remote controller through communication signals.

[0063] The first rotating mechanism 1 has a structure as follows Figure 3 As shown, it includes a motor B1-1, the motor B1-1 is screwed to the first motor flange 1-2, the first motor flange 1-2 is bolted to one end of the load-bearing shaft 1-3 through a connecting flange, the load-bearing shaft 1-3 is installed in the seat bearing 1-4, and has an interference fit with the seat bearing 1-4, the seat bearing 1-4 is fixed to the base 6 through a bearing frame, the other end of the load-bearing shaft 1-3 is fixed to the bearing flange 1-5, and the bearing flange 1-5 is bolted to the frame 7, that is, the motion output end of the first rotating mechanism 1 transmits power, so that the frame 7 as a whole is Figure 1 The Y-axis in the middle is the axis of rotation; the seat bearing 1-4 is fixedly mounted on the base 6 by bolts, so that the first rotating mechanism 1 is fixed on the base 6, and the motor B1-1 is connected to the remote controller through a communication signal.

[0064] like Figure 2As shown, the second rotating mechanism 5 includes a motor A5-1 fixedly connected to the frame 7, the end key of the output shaft of the motor A5-1 is connected to the second motor flange 5-2, the motor A5-1 is electrically connected or signal-connected to the remote control end, the second rotating mechanism 5 rotates around the output shaft of the motor A5-1, and a position 8 is reserved for the fixture between the second motor flange 5-2 and the flange bearing 2-4. The workpiece to be welded is installed on the fixture, and the fixture is divided into two parts, which are fixedly connected to the second motor flange 5-2 and the flange bearing 2-4 respectively by bolts.

[0065] like Figure 4 As shown, the locking mechanism 2 is arranged on the inner side of the right frame 2-1 of the frame 7, and includes a locking block 2-2, which is sleeved with the right frame 2-1 and fixed by bolts. The locking disk 2-3 is a disk structure and a threaded shaft is fixedly passed through the center of the disk. A threaded through hole matching the threaded shaft is opened in the center of the locking block 2-2 away from the right frame 2-1. One end of the threaded shaft passes through the threaded through hole and is fixedly connected to the right frame 2-1. The other end of the threaded shaft is fixedly connected to a flange bearing 2-4 and has an interference fit with the flange bearing 2-4. The center of the flange bearing 2-4 is located on the extension line of the output shaft of the motor A5-1. The flange bearing 2-4 is provided with an internal threaded hole, through which it is connected to the workpiece clamp bolt at the reserved position 8. By manually rotating the locking disk 2-3, the threaded shaft expands and contracts in the locking block 2-2, thereby driving the clamp to adjust the spacing of the workpieces to be welded.

[0066] like Figure 1 and Figure 5 As shown, the gantry moving mechanism 3 includes a gantry, and the gantry includes two parallel vertical frames, a crossbeam is arranged between the tops of the two vertical frames, and the frame 7 is located between the two vertical frames and below the crossbeam. A transverse moving mechanism 3-2 is arranged on the crossbeam, and the transverse moving mechanism 3-2 includes a motor C3-4 fixed to one end of the crossbeam and a slide rail arranged on the crossbeam. The motor C3-4 is connected to the remote controller signal, and the slide rail is slidably connected to the longitudinal beam through the transmission mechanism. The remote controller sends a signal to the motor C3-4 to control the longitudinal beam to move in a direction parallel to the X-axis.

[0067] The longitudinal moving mechanism 3-1 includes two longitudinal guide rails arranged on the longitudinal beam. Motor D3-5 and limit mechanism 3-3 are respectively arranged near the two ends of the longitudinal beam. Motor D3-5 is connected to the remote controller signal. A slide is slidably installed between the two longitudinal guide rails. A transverse rack is arranged on the slide. A gear is arranged on the output shaft of motor D3-5. The gear is meshed with the transverse rack for transmission. The motor D3-5 can drive the gear to rotate, thereby driving the slide to move along the longitudinal guide rail, that is, in a direction parallel to the Z axis.

[0068] The welding mechanism 4 includes a welding gun 4-1 and a wire feeding mechanism 4-2. The welding gun 4-1 is installed at the bottom of the slide. The welding gun 4-1 is driven by the longitudinal moving mechanism 3-1 and the transverse moving mechanism 3-2 to move horizontally up and down and left and right on the gantry beam. The wire feeding mechanism 4-2 includes a motor E and a clamping wheel. The motor E is connected to the remote control terminal signal to control the wire feeding mechanism 4-2 to feed the wire to the welding gun 4-1 during the welding process. The welding point of the workpiece to be welded is located directly below the welding gun 4-1. The extension line of the welding gun 4-1 and the output shaft of the motor A5-1 are in the same plane. The welding gun 4-1 can maintain vertical operation without a welding dead point, thereby ensuring the welding quality.

[0069] The spatial curve welding device of the present invention is a universal mechanism, and a fixture reserved position 8 is reserved in advance. When different welding workpieces are replaced, the fixture can be customized according to the shape and size of the workpiece.

[0070] The space curve welding method of the present invention has the following process: Fig. 9 As shown, the workpiece to be welded is modeled by three-dimensional software, and the output data is transmitted to the remote controller to control the space curve welding device to perform automatic welding. The specific implementation is as follows:

[0071] Step 1: Figure 6 , Figure 7 , Figure 8 As shown, the two parts of the clamp are respectively installed at the reserved position 8 of the clamp between the second motor flange 5-2 and the flange bearing 2-4, and fixed by bolts, and then the two parts of the workpiece to be welded are respectively installed on the clamp, and the locking plate 2-3 is manually rotated to control the clamp to connect the welding surfaces of the workpiece to be welded, and each motor is manually controlled to zero, and the position of the workpiece to be welded at this time is set as the initial position.

[0072] Step 2: 3D software modeling, path planning for the weld, extracting the coordinates of each discrete welding point on the weld trajectory at the initial position, taking each discrete welding point at the top as the target, and calculating the position output results of each discrete point of the weld in turn;

[0073] like Fig.10 As shown, the model is built in the 3D software according to the initial position of the workpiece. The extension direction of the rotation axis of the first rotating mechanism 1 is set to the Y axis, the extension direction of the rotation axis of the second rotating mechanism 5 is set to the X axis, and the movement direction of the longitudinal moving mechanism 3-1 is set to the Z axis. The world coordinate system is established with the intersection of the X axis and the Y axis as the spatial origin. The welding point spacing is input in the workpiece model, as shown in FIG. Fig.13 As shown, a welding trajectory curve is formed at the position where the two surfaces to be welded are butted. The welding curve 9 is calculated by identifying all points at the position where the two surfaces to be welded are butted through the point cloud. The welding curve 9 is discretized into points according to the welding point spacing requirements to obtain the initial position coordinates of each discrete welding point 10.

[0074] With the welding point at the top as the goal, the motor expected angle angle_set(t) and actual angle angle(t) corresponding to each discrete welding point on the welding curve 9 are calculated in sequence, as well as the position data of each discrete welding point on the X-axis and Z-axis, which are the position output results of each discrete point of the weld.

[0075] The expected angle angle_set(t) is the angle that the motor needs to rotate when each discrete welding point rotates to the world coordinate XZ plane with the X axis as the axis, and the actual angle angle(t) is the angle that the motor has rotated at this time.

[0076] The initial coordinates of the Nth discrete welding point are recorded as (x0, y0, z0); the discrete welding point is rotated around the X axis to the world coordinate XZ plane, at which time the y0 coordinate is 0, and the homogeneous matrix is ​​calculated, such as Fig.14 As shown, the rotation angle α of the discrete welding point around the X-axis is the expected angle angle_set(t) of the motor A5-1. The actual angle angle(t) of the motor at the Nth discrete welding point is the angle that the motor A5-1 has rotated at this time, that is, the expected angle of the motor A5-1 at the N-1th discrete welding point, as shown in Fig.14 As shown; the discrete welding point and the two surfaces to be welded each form a prime line, and the angle between the two prime lines is angle θ, as shown Fig.15 As shown, a plane is made through the angle θ / 2, which is the angle bisector of the tangent plane of the two surfaces. A unit vector is made through the angle θ / 2, and a polar unit vector coordinate system is established with the origin of the world coordinate system as the origin, and the angle between the angle bisector and the Z axis is obtained. That is the expected angle of motor B1-1, and the actual angle of motor B1-1 is the expected angle of motor B1-1 at the N-1th point; a homogeneous matrix transformation is performed according to the obtained expected rotation angle, that is, the angle bisector plane is made parallel to the Z axis, and the final position (x1, 0, z1) of the discrete welding point after transformation is obtained, and x1 and z1 are the position data of the welding gun 4-1 on the X-axis and Z-axis.

[0077] Step 3, input the posture output result obtained in step 2 to the remote controller, and the remote controller sends a signal to control the first rotating mechanism 1, the second rotating mechanism 5, the gantry moving mechanism 3, and the welding mechanism 4 to move jointly, and weld each discrete weld point on the welding curve 9 from the starting point to the end point in sequence, until all discrete weld points are welded, and the spatial curve welding is completed.

[0078] Specifically, step 3 outputs the position and posture output results of each discrete point of the weld in step 2, imports them from the PC to the reserved serial port of the single-chip data of the remote controller, and inputs the wire feeding speed required for welding into the reserved serial port, and manually controls the wire feeding speed parameters according to actual use requirements. The remote controller controls the motor A5-1, the motor B1-1, the motor C3-4, the motor D3-5, and the motor E in the wire feeding mechanism 4-2 to jointly operate; Fig.11 As shown, motor A5-1 controls the welding workpiece to rotate around the output shaft of motor A5-1 according to the input data, and motor B1-1 controls the welding workpiece to rotate on the Y axis according to the posture data to control the workpiece posture; motor C3-4 controls the welding gun to move in the direction parallel to the X axis according to the posture data, and motor D3-5 controls the welding gun to move on the Z axis according to the posture data to control the position of the welding gun; wire feeding mechanism 4-2 controls the wire feeding speed according to the input data.

[0079] like Fig.12 As shown, motor A5-1 and motor B1-1 are equipped with ESCs with different IDs. The remote controller communicates with the ESCs through bus communication. On the one hand, it sends the current value of motion control, and on the other hand, it identifies the corresponding motor by judging the ID of the ESC, which is convenient for feedback data analysis. The ESC sends control signals to control the speed of motor A5-1 and motor B1-1;

[0080] The remote controller performs closed-loop control on motor A5-1 and motor B1-1 through a cascade PID control algorithm. The first-loop controller is an angle controller that calculates the desired speed speed_set(t):

[0081]

[0082] Where err1(t) = angle_set(t) - angle(t), kp1, ki1, kd1 are the three PID parameters of the first loop, angle_set(t) is the expected angle, and angle(t) is the actual angle;

[0083] The second-loop controller is a speed controller, which calculates the control quantity u(t) and controls the rotation speed of motor A5-1 and motor B1-1 according to the control quantity u(t);

[0084]

[0085] Among them, err2(t)=speed_set(t)-speed(t), kp2, ki2, kd2 are the three PID parameters of the second loop, speed(t) is the actual speed, and the actual speed is the working speed of the motor at time t, that is, the actual speed of the motor at the Nth welding point is the expected speed of the N-1th welding point.

[0086] The remote controller uses pulse signals to open-loop control motors C3-4 and D3-5 to achieve the displacement distance of the welding gun on the X-axis and Z-axis. The hardware is used to open a direct data transmission path between RAM and I / O devices, that is, to use DMA to generate M pulse signals. Among them, x 总 is the difference between the position data of welding gun 4-1 of two adjacent discrete welding points, x i is the displacement of the welding gun 4-1 per rotation of the motor output shaft, a is the subdivision number of the driver connected to the motor, and b is the motor step angle; after the DMA output is completed, the DMA transfer completion event in the hardware interrupt is triggered, an interrupt is generated, and the output of the pulse signal is stopped to achieve the number of control pulse signals, thereby controlling the displacement of the welding gun driven by C3-4 and motor D3-5;

[0087] The remote controller simultaneously sends a pulse signal to the motor E of the wire feeding mechanism 4-2 to control the start and stop and speed of the motor E, thereby realizing speed control of the wire feeding, that is, inputting the required wire feeding speed and outputting the pulse signal frequency controlled by the motor; the calculation formula is: V=n*2π*r, V is the wire feeding speed, n is the motor speed, r is the radius of the clamping wheel, f is the pulse frequency, b is the motor step angle, and a is the number of subdivisions of the driver connected to the motor;

[0088] The remote controller controls motor A5-1, motor B1-1, motor C3-4, D3-5, and motor E of wire feeding mechanism 4-2 to perform synchronous and continuous movement respectively until the welding of all discrete welding points is completed and the spatial curve welding work is completed.

[0089] Compared with not using DMA, this method greatly reduces the burden on the CPU, improves the efficiency of the CPU, and improves the real-time performance of the control system.

[0090] The spatial curve welding device of the present invention has the following working principle:

[0091] In the 3D software, a model of the workpiece to be welded is established, the 3D data of the welding curve is extracted, the motion data of the mechanical motion is calculated, and the sequential mechanical motion of the welding point continuously moving to the top is generated, thereby realizing the data of automatic welding of the spatial curve; the data obtained on the PC side and the wire feeding speed requirements of the wire feeding mechanism are imported into the single-chip data reserved serial port of the remote controller, and the remote controller realizes the position control of motor A5-1 and motor B1-1 through the cascade PID control algorithm, generates a specified number of pulse signals through DMA, and controls the operation of motor C3-4, motor D3-5, and motor E with a given pulse number; motor A5-1, motor B1-1, motor C3-4, motor D3-5 , motor E performs synchronous continuous motion; the remote control end controls motor A5-1 according to the posture result to drive the workpiece to be welded to rotate with the output shaft of motor A5-1 as the axis, and rotates the point to be welded to the first and second quadrants of the XZ plane in space; motor B1-1 rotates according to the data result, drives the frame part to rotate with Y as the axis, corrects the welding posture of the workpiece, so that the welding gun 4-1 can perform welding operations on the angle bisector plane formed by the workpiece cutting plane, and avoids the interference of the workpiece on the welding gun position during welding; motor C3-4 and motor D3-5 control the welding gun 4-1 to move on the X axis and Z axis respectively to reach the welding position, and motor E controls the wire feeding speed to feed the welding wire to the welding gun 4-1 for welding. According to the posture data result, the motor is controlled to repeat the above process to realize the automation of spatial curve welding.

[0092] The spatial curve welding method of the present invention utilizes three-dimensional software to plan the path of the weld, and controls the cooperation between a two-degree-of-freedom rotating mechanism and a two-degree-of-freedom moving mechanism through a cascade PID control algorithm and a pulse signal, so that each welding point on the welding line is always kept directly above when the welding gun posture remains unchanged, and the welding gun can maintain vertical operation to improve the welding quality and eliminate welding dead points.

Claims

1. Space curve welding device, characterized in that: The invention comprises a mechanical mechanism and a remote controller connected by communication signals, wherein the mechanical mechanism comprises a frame (7), a gantry moving mechanism (3) is arranged outside and above the frame (7), a second rotating mechanism (5) and a locking mechanism (2) are respectively fixedly connected to two opposite side walls of the frame (7), a first rotating mechanism (1) is also symmetrically arranged on the outer side wall of the frame (7), the rotation axis extension direction of the first rotating mechanism (1) and the rotation axis extension direction of the second rotating mechanism (5) are orthogonal to each other, a welding mechanism (4) is installed at the motion output end of the gantry moving mechanism (3), and the first rotating mechanism (1), the second rotating mechanism (5), the gantry moving mechanism (3) and the welding mechanism (4) are respectively connected to the remote controller by communication signals; The space curve welding method of the space curve welding device is specifically implemented according to the following steps: Step 1, respectively fix the two parts of the clamp to the second motor flange (5-2) and the flange bearing (2-4), then respectively install the two parts of the workpiece to be welded on the clamp, manually rotate the locking plate (2-3), control the clamp to align the welding surfaces of the workpiece to be welded, manually control each motor to zero, and set the position of the workpiece to be welded at this time as the initial position; Step 2: 3D software modeling, path planning for the weld, extracting the coordinates of each discrete welding point on the weld trajectory at the initial position, taking each discrete welding point at the top as the target, and calculating the position output result of each discrete point of the weld; Step 3, inputting the position output result obtained in step 2 into the remote controller, the remote controller sends a signal to control the first rotating mechanism (1), the second rotating mechanism (5), the gantry moving mechanism (3), and the welding mechanism (4) to move jointly, and weld each discrete welding point of the weld until all the discrete welding points of the weld are welded, and the spatial curve welding is completed; The specific operation of step 2 is to model the workpiece according to the initial position state in the three-dimensional software, set the extension direction of the rotation axis of the first rotating mechanism (1) to be the Y axis, the extension direction of the rotation axis of the second rotating mechanism (5) to be the X axis, and the movement direction of the longitudinal moving mechanism (3-1) to be the Z axis, establish a world coordinate system with the intersection of the X axis and the Y axis as the spatial origin, input the welding point spacing in the workpiece model, form a welding trajectory curve at the position where the two surfaces to be welded are butted, calculate and form a welding curve (9) through all points at the butt position of the two surfaces to be welded, and discretize the welding curve (9) into points according to the welding point spacing requirements to obtain the initial position coordinates of each discrete welding point (10); With the welding point at the top as the goal, the motor expected angle angle_set(t) and actual angle angle(t) corresponding to each discrete welding point on the welding curve (9) are calculated in turn, as well as the position data of each discrete welding point on the X-axis and Z-axis, which are the position output results of each discrete point of the weld; The expected angle angle_set(t) is the angle that the motor needs to rotate when each discrete welding point rotates from the X axis to the world coordinate XZ plane. The actual angle angle(t) is the angle that the motor has rotated at this time. The initial coordinates of the Nth discrete welding point are denoted as (x0, y0, z0); the discrete welding point is rotated around the X-axis to the world coordinate XZ plane, at which the y0 coordinate is 0. Through homogeneous matrix calculation, the rotation angle α of the discrete welding point around the X-axis is obtained, which is the expected angle angle_set(t) of motor A(5-1). The actual angle angle(t) of the motor at the Nth discrete welding point is the angle that motor A(5-1) has rotated at this time, that is, the expected angle of motor A(5-1) at the N-1th discrete welding point; the discrete welding point forms a prime line with each of the two surfaces to be welded, and the angle between the two prime lines is angle θ. A plane is made through angle θ / 2, which is the angle bisector of the tangent plane of the two curved surfaces. A unit vector is made through angle θ / 2, and a polar unit vector coordinate system is established with the origin of the world coordinate system as the origin, to obtain the angle between the angle bisector and the Z axis. That is, the expected angle of motor B (1-1), and the actual angle of motor B (1-1) is the expected angle of motor B (1-1) at the N-1th point; a homogeneous matrix transformation is performed according to the obtained expected rotation angle, that is, the angle bisector plane is made parallel to the Z axis, and the final position (x1, 0, z1) of the discrete welding point after transformation is obtained, and x1 and z1 are the position data of the welding gun (4-1) on the X axis and the Z axis; Specifically, step 3 includes: importing the output results of the position and posture of each discrete point of the weld in step 2 into the reserved serial port of the single-chip data of the remote controller, and inputting the wire feeding speed required for welding into the reserved serial port, and the remote controller controls the motor A (5-1), the motor B (1-1), the motor C (3-4), the motor D (3-5), and the wire feeding mechanism (4-2) to operate synchronously and continuously; The remote controller is connected to the ESC via bus communication. The ESC sends control signals to control the speed of motor A (5-1) and motor B (1-1). Motor A (5-1) and motor B (1-1) are equipped with ESCs with different IDs. The remote controller performs closed-loop control on motor A (5-1) and motor B (1-1) via a cascade PID control algorithm. The first-loop controller is an angle controller that calculates the desired speed speed_set(t): Where err1(t)=angle_set(t)-angle(t), kp1, ki1, kd1 are the three PID parameters of the first loop, angle_set(t) is the expected angle, and angle(t) is the actual angle; The second loop controller is a speed controller, which calculates the control quantity u(t) and controls the rotation speed of motor A (5-1) and motor B (1-1) according to the control quantity u(t); Where err2(t)=speed_set(t)-speed(t), kp2, ki2, kd2 are the three PID parameters of the second loop, speed(t) is the actual speed, the actual speed is the working speed of the motor at time t, that is, the actual speed of the motor at the Nth welding point is the expected speed of the N-1th welding point; The remote controller performs open-loop control of motor C (3-4) and motor D (3-5) through pulse signals, and uses hardware to open a direct data transmission path between RAM and I / O devices, that is, using DMA to generate M pulse signals. Among them, x 总 is the difference between the position data of the welding gun (4-1) of two adjacent discrete welding points, x i is the displacement of the welding gun (4-1) per rotation of the motor output shaft, a is the number of subdivisions of the driver connected to the motor, and b is the motor step angle. After the DMA output is completed, the DMA transfer completion event in the hardware interrupt is triggered, an interrupt is generated, and the output of the pulse signal is stopped to achieve the number of control pulse signals, thereby controlling the displacement of the welding gun driven by C (3-4) and motor D (3-5); The remote controller controls the start and stop and the rotation speed of the wire feeding mechanism (4-2) through the pulse signal at the same time, thereby realizing the start and stop of the welding wire feeding and the wire feeding speed control; the output pulse signal frequency calculation formula is: f is the pulse signal frequency, b is the motor step angle, and a is the subdivision number of the driver connected to the motor; the calculation formula for the wire feeding speed input value is: V = n*2π*r, V is the wire feeding speed, n is the motor speed, and r is the radius of the pressure wheel; The remote controller controls motor A (5-1), motor B (1-1), motor C (3-4), motor D (3-5) and wire feeding mechanism (4-2) to perform synchronous and continuous movement respectively until the welding of all discrete welding points is completed, thus completing the spatial curve welding work.

2. The space curve welding device according to claim 1, characterized in that: The first rotating mechanism (1) comprises a motor B (1-1), the output end of the motor B (1-1) is fixedly connected to a load-bearing shaft (1-3) via a first motor flange (1-2), one end of the load-bearing shaft (1-3) passes through a seat bearing (1-4) and is fixedly connected to a bearing flange (1-5), the bearing flange (1-5) is fixedly connected to a frame (7), the load-bearing shaft (1-3) and the seat bearing (1-4) are interference fit, the seat bearing (1-4) is fixedly connected to a base (6), and the motor B (1-1) is connected to the remote controller via a communication signal.

3. The space curve welding device according to claim 1, characterized in that: The second rotating mechanism (5) comprises a motor A (5-1) fixedly connected to the frame (7), the end of the output shaft of the motor A (5-1) is key-connected with a second motor flange (5-2), and the motor A (5-1) is connected to the remote controller via a communication signal.

4. The space curve welding device according to claim 3, characterized in that: The locking mechanism (2) comprises a locking block (2-2) fixedly connected to the inner side of the frame (7); a locking disk (2-3) is connected to the side of the locking block (2-2) facing away from the frame (7); and a flange bearing (2-4) is fixedly connected to the side of the locking disk (2-3) away from the locking block (2-2); The locking disk (2-3) is a disk structure, a threaded shaft is fixedly connected to the center of the disk, a threaded through hole matching the threaded shaft is opened at the center of the locking block (2-2) on one side away from the frame (7), one end of the threaded shaft passes through the threaded through hole and is fixedly connected to the frame (7), and a flange bearing (2-4) is fixedly connected to the other end of the threaded shaft and is interference fit with the flange bearing (2-4), and the center of the flange bearing (2-4) is located on the extension line of the output shaft of the motor A (5-1).

5. The space curve welding device according to claim 1, characterized in that: The gantry moving mechanism (3) comprises a gantry, on which a transverse moving mechanism (3-2) is arranged, and on which a longitudinal moving mechanism (3-1) is slidably connected, wherein the moving directions of the longitudinal moving mechanism (3-1) and the transverse moving mechanism (3-2) are orthogonal to each other, and a moving output end of the longitudinal moving mechanism (3-1) is fixedly connected to the welding mechanism (4), and the transverse moving mechanism (3-2) and the longitudinal moving mechanism (3-1) are located above the frame (7).

6. The space curve welding device according to claim 5, characterized in that: The gantry comprises two parallel vertical frames, a horizontal beam is arranged between the top ends of the two vertical frames, the horizontal movement mechanism (3-2) comprises a motor C (3-4) fixed to one end of the horizontal beam and a slide rail arranged on the horizontal beam, the slide rail is slidably connected to the longitudinal beam through a transmission mechanism, and the motor C (3-4) is connected to a remote controller signal; The longitudinal moving mechanism (3-1) comprises two longitudinal guide rails symmetrically arranged on the longitudinal beam, a motor D (3-5) and a limit mechanism (3-3) are respectively arranged near the two ends of the longitudinal beam, a slide is slidably installed between the two longitudinal guide rails, a transverse rack is arranged on the slide, a gear is arranged on the output shaft of the motor D (3-5), the gear is meshed with the rack for transmission, and the motor D (3-5) is connected to the remote controller signal.

7. The space curve welding device according to claim 1, characterized in that: The welding mechanism (4) comprises a welding gun (4-1) and a wire feeding mechanism (4-2); the welding gun (4-1) is fixedly connected to the motion output end of the gantry moving mechanism (3); and the wire feeding mechanism (4-2) is connected to a remote controller signal.

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