Pipe bending processing method of mobile pipe bending robot

Abstract

This invention relates to a pipe bending method using a mobile pipe bending robot, comprising a coordinate system establishment step, a machining trajectory planning step, and a pipe bending execution step. The coordinate system establishment step includes: S11, establishing a base coordinate system; S12, establishing a robot base coordinate system; S13, establishing a robot machining coordinate system; and S14, establishing a pipe fitting coordinate system. The machining trajectory planning step includes: S21, establishing a 3D model of the pipe fitting; S22, calibrating the robot machining coordinate system based on the 3D model of the pipe fitting; and S23, calculating the pipe fitting machining parameters. The pipe bending execution step involves the machining trajectory Traj having a discontinuity point N for each bend. The robot first moves to the discontinuity point to perform the pipe bending operation, and after the bend is completed, it continues to the next trajectory segment. This invention, based on a mobile pipe bending robot, proposes a pipe bending method that improves bending accuracy, shortens overall processing time, and increases bending efficiency.

Description

Technical Field

[0001] This invention relates to the field of pipe bending technology (B21D7 / 00), specifically to a pipe bending processing method using a mobile pipe bending robot. Background Technology

[0002] Pipe bending is a processing technique that involves bending metal pipes into specific shapes. Pipe bending equipment bends the metal pipes along a certain angle to obtain the desired pipe shape or curved component. Pipe bending is widely used in automobile manufacturing, bridge construction, aerospace, chemical equipment, and other fields, and its precision directly affects the quality of the finished pipe fittings. Compared to traditional pipe bending machines and CNC pipe bending machines, pipe bending robots, which combine industrial robotic arms with bending mechanisms, feature automatic loading and unloading, and high flexibility.

[0003] Pipe bending robots typically employ an industrial six-degree-of-freedom robotic arm as the main body, with an end effector mounted on the robot's end joint axis serving as the bending mechanism. Chinese patent document CN113351704A discloses a trajectory control and forming processing method for a pipe bending robot, which focuses on the design and optimization of the pipe bending processing path for a six-degree-of-freedom pipe bending robot. Its main idea is to first establish a three-dimensional model of the pipe, then calibrate the coordinate system of the pipe bending robot. Typically, the center point of the robot's base is used as the base coordinate system, and the center point of the clamping mechanism of the bending mechanism is used as the processing coordinate system base point. This determines the control points for the pipe bending processing path, generates the processing path, and sets the robot to automatically run to those points for bending processing.

[0004] The mobile pipe bending robot, based on the fundamental structure of a pipe bending robot, is equipped with a sliding rail on its base, expanding the robot's working range and increasing its flexibility, enabling it to process long straight pipes. The newly added sliding rail extends the axial degrees of freedom of the pipe bending robot. Existing trajectory calculation methods are limited to fixed positions and are not efficient for mobile pipe bending robots. Therefore, there is currently a lack of a trajectory calculation method based on mobile pipe bending robots to ensure the reliability and efficiency of the processing trajectory, thereby guaranteeing the accuracy of the final pipe fittings. Summary of the Invention

[0005] This invention addresses the technical problem that ordinary trajectory algorithms are limited to fixed positions and have relatively poor dynamic performance. It proposes a method for calculating the bending trajectory of a mobile pipe bending robot. Based on an established coordinate system, the relative position and posture of the pipe are determined. A time control parameter is added, and the joint axis motion of the pipe bending robot and the relative motion based on the sliding straight rail are superimposed by solving the final shape of the bent pipe. The time function of the processing trajectory of the end effector is calculated, which optimizes the moving speed of the end effector along the trajectory, thereby shortening the processing time and improving work efficiency.

[0006] To achieve the above objectives, the technical solution of the present invention is as follows:

[0007] The pipe bending process of a mobile pipe bending robot includes steps for establishing a coordinate system, planning the machining trajectory, and executing the pipe bending operation.

[0008] The steps for establishing the coordinate system are as follows:

[0009] S11. Establish a base coordinate system: The origin O0 of the base coordinate system is set at the center of the linear guide rail at the bottom of the robot. The positive direction of the Z-axis Z0 is vertically upward and perpendicular to the ground. The positive direction of the X-axis X0 is determined based on the right-hand rule. The Y-axis Y0 is perpendicular to the X0O0Z0 plane, with the foot of the perpendicular intersecting at point O0. The parameters of the base coordinate system are (X0, Y0, Z0, A0, B0, C0), where A0, B0, and C0 represent the initial Euler angles of the base coordinate system O0.

[0010] S12. Establish the robot's base coordinate system: The origin O1 of the robot's base coordinate system is located at the center point of the six-degree-of-freedom robot base; the positive direction of the Z-axis Z1 is vertically upward and perpendicular to the ground; the positive direction of the X-axis X1 is the same as the X0 direction of the base coordinate system; the Y-axis Y1 is perpendicular to the X1O1Z1 plane, with the foot of the perpendicular intersecting at point O1; the initial position of the coordinate system coincides with the base coordinate system, and the parameters are (X1, Y1, Z1).

[0011] S13. Establish the robot machining coordinate system: The origin O2 of the robot machining coordinate system is set at the center point of the arc of the bending and clamping mechanism at the end of the robot. The positive direction of the Z-axis Z2 of the coordinate system is in contact with the tangent surface of the circular mold and faces upward. The X-axis X2 of the coordinate system coincides with the normal to the center of the arc of the clamping mechanism, and its direction is horizontal to the right. The Y-axis Y2 of the coordinate system is perpendicular to the X2O2Z2 plane, and the foot of the perpendicular intersects at point O2. The parameters of the robot machining coordinate system are (X2, Y2, Z2, A2, B2, C2), where A2, B2, and C2 represent the rotation angles around the X, Y, and Z axes of the base coordinate system O0.

[0012] S14. Establish the pipe fitting coordinate system: The origin O3 of the pipe fitting coordinate system is set at the center point of the arc of the clamping mechanism of the gripper. The positive direction of the Z-axis Z3 of the coordinate system is in contact with the tangential surface of the clamping mold and faces upward. The positive direction of the X-axis X2 of the coordinate system coincides with the center normal of the arc surface of the clamping mechanism. The positive direction of the Y-axis Y3 of the coordinate system is perpendicular to the X3O3Z3 plane, and the foot of the perpendicular intersects at point O3. The parameters of the robot machining coordinate system are (X3, Y3, Z3).

[0013] The processing trajectory planning steps are as follows:

[0014] S21. Establish a 3D model of the pipe fitting: Determine the processing parameters of the pipe fitting, including the bending angle of each bend, the position of the starting point of the bend, and the posture angle at that position;

[0015] S22. Robot machining coordinate system calibration based on the 3D model of the pipe fitting: align the origin O2 of the robot machining coordinate system with the starting point of the pipe fitting machining, i.e., one end point, so that the positive direction of the X-axis X2 of the coordinate system points to the direction of the pipe fitting, the positive direction of the Z-axis Z2 of the coordinate system is vertically upward, and the Y-axis Y2 of the coordinate system is perpendicular to the X2O2Z2 plane, with the foot of the perpendicular intersecting at point O2.

[0016] S23. Calculation of pipe fitting machining parameters:

[0017] Pipe fitting processing starting point position N0(X) 20 Y 20 Z 20 A 20 B 20 C 20 );

[0018] The starting point of the first bend is N1(X) 21 Y 21 Z 21 A 21 B 21 C 21 );

[0019] Among them, X 21 =X 20 +L1;Y 21 =Y 20 Z 21 =Z 20 A 21 =A 20 B 21 =B 20 C 21 =C 20 ;

[0020] The first bend angle is θ1(0, θ1);

[0021] The starting point of the second bend is N2(X) 22 Y 22 Z 22 A 22 B 22 C 22 );

[0022] Among them, X 22 =X 21 +L2=X 20 +L1+L2;Y 22 =Y 21 =Y 20 Z 22 =Z 21 =Z 20 A22 =A 21 ± α 21 =A 20 ± α 21 B 22 =B 21 =B 20 C 22 =C 21 =C 20 ;

[0023] The second bend angle is θ2(0, θ2);

[0024] The starting point of the nth bend is N. n (X 2n Y 2n Z 2n A 2n B 2n C 2n );

[0025] Among them, X 2n =X 20 + ;Y 2n =Y 2(n-1) =…=Y 21 =Y 20 Z 2n =Z 2(n-1) =…=Z 21 =Z 20 A 2n =A 2(n-1) ± α 2(n-1) B 2n =B 2(n-1) =…=B 21 =B 20 C 2n =C 2(n-1) =…=C 21 =C 20 ;

[0026] The steps for bending the pipe are as follows:

[0027] The processing trajectory Traj has the starting point N of each bend as the discontinuity point. The robot first moves to the discontinuity point of the trajectory to perform the pipe bending operation. After the processing of that bend is completed, it continues to the next segment of the trajectory.

[0028] From the starting point of pipe fitting processing to the starting point of the first bend

[0029] Traj N01 =(X N01 (t), Y N01 (t), ZN01 (t), A N01 (t), B N01 (t), C N01 (t))

[0030] in:

[0031] X N01 (t)=X 20 +(X 21 -X 20 )*t / T

[0032] Y N01 (t)=Y 20 +(Y 21 -Y 20 )*t / T

[0033] Z N01 (t)=Z 20 +(Z 21 -Z 20 )*t / T

[0034] ;

[0035] Therefore, we can conclude that:

[0036] ;

[0037] ;

[0038] ;

[0039] In the formula:

[0040] A N01 (t)=A 20 +w 弯 *t*sign(A 21 -A 20 )

[0041] B N01 (t)=B 20 +w 弯 *t*sign(B 21 -B 20 )

[0042] C N01 (t)=C 20 +w 弯 *t*sign(C 21 -C 20 )

[0043] Pipe fitting machining trajectory segment n

[0044] TrajN(n-1)(n) =(X N(n-1)(n) (t), Y N(n-1)(n) (t), Z N(n-1)(n) (t), A N(n-1)(n) (t), B N(n-1)(n) (t), C N(n-1)(n) (t))

[0045] in:

[0046] ;

[0047] ;

[0048] ;

[0049] X 2(n-1)(n) (t)=X 2(n-1)(n) +(X 2(n-1) -X 20 )*t / T

[0050] Y 2(n-1)(n) (t)=Y 2(n-1)(n) +(Y 2(n-1) -Y 20 )*t / T

[0051] Z 2(n-1)(n) (t)=Z 2(n-1)(n) +(Z 21 -Z 20 )*t / T

[0052] A N(n-1)(n) (t)=A 2(n-1) +w 弯 *t*sign(A 2(n-1) -A 2(n) )

[0053] B N(n-1)(n) (t)=B 2(n-1) +w 弯 *t*sign(B 2(n-1) -B 2(n) )

[0054] C N(n-1)(n) (t)=C 2(n-1) +w 弯 *t*sign(C 2(n-1) -C 2(n) ).

[0055] As an improvement, a trajectory optimization step is also included, including...

[0056] (1) Optimization of pipe bend spacing: The horizontal movement speed of the mobile robot end relative to the robot base is V1, and the movement speed of the robot base relative to the base coordinate system on the sliding straight rail is V2; for the base coordinate system O0 and the pipe coordinate system O3, the sum of the horizontal movement speed of the robot is (V1+V2).

[0057] For each bend spacing, the bend spacing is... It can be shortened to

[0058] ;

[0059] (2) Head angle calculation optimization: The initial posture of the end effector head of the mobile robot is (A0, B0, C0). The posture at the starting point of the first bend remains unchanged. Starting from the second bend, the head angle is calculated according to the pipe processing parameters. The expression is as follows:

[0060] A 21 =A 20 n=1;

[0061] A 2n =A 2(n-1) ± α 2(n-1) n>1;

[0062] ;

[0063] α represents the angle value of the machine head rotating around the pipe, N is the starting point of the bend arc, and N' is the ending point of the bend arc. During the processing, after completing the bend, the robot uses this posture as the initial posture to calculate the rotation angle of the next bend.

[0064] The beneficial effects of this invention are as follows: It proposes a processing trajectory calculation method based on a mobile pipe bending robot. By establishing a coordinate representation method that is different from that in Chinese patent document CN113351704A, it can intuitively represent the relative position and posture relationship between the pipe and the processing equipment, reducing the programming complexity of the robot's processing trajectory. The processing path is generated by calculating the final shape of the pipe, and the processing trajectory time function is obtained by combining the robot's joint axis movement speed and the sliding rail movement speed. This allows for precise control of the robot's processing position and movement time, thereby achieving reliability in the mobile pipe bending robot's processing process. Attached Figure Description

[0065] Figure 1 A schematic diagram of the mobile pipe bending robot in operation;

[0066] Figure 2 A schematic diagram of coordinate system calibration;

[0067] Figure 3 A diagram illustrating the meaning of each parameter;

[0068] Figure 4 A schematic diagram of the robot's machining coordinate system;

[0069] Figure 5 This is a schematic diagram of an M-type tube;

[0070] Figure 6 This is a schematic diagram of the pipe bending process.

[0071] In the diagram: 1. Industrial six-degree-of-freedom robotic arm; 2. Pipe bending mechanism; 3. Sliding straight rail; 4. Pipe clamp. Detailed Implementation

[0072] Example 1

[0073] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0074] This invention proposes a pipe bending method using a mobile pipe bending robot. The system's structure is as follows: Figure 1 As shown, it includes: an industrial six-degree-of-freedom robotic arm 1; a pipe bending mechanism 2 connected to the end of the sixth axis of the joint of the industrial six-degree-of-freedom robotic arm 1; a sliding straight rail 3 installed at the bottom of the industrial six-degree-of-freedom robotic arm 1; and a pipe clamp 4 located on the front side of the industrial six-degree-of-freedom robotic arm 1.

[0075] This invention proposes a method for calculating the machining trajectory of a mobile pipe bending robot, including a coordinate system establishment step, a machining trajectory planning step, a trajectory optimization step, and a pipe bending execution step.

[0076] I. Steps for establishing a coordinate system In a better example, such as Figure 2 As shown, it includes:

[0077] S11. Establish a base coordinate system: The origin O0 of the base coordinate system is located at the center-symmetric position of the sliding rail 3. The positive direction of the Z-axis Z0 is vertically upward and perpendicular to the ground; the positive direction of the X-axis X0 is determined based on the right-hand rule, and in this example, it is horizontal to the right; the Y-axis Y0 is perpendicular to the X0O0Z0 plane, with the foot of the perpendicular intersecting at point O0; the parameters of the base coordinate system O0 are (X0, Y0, Z0, A0, B0, C0); where X, Y, and Z represent the three-dimensional position points, and A0, B0, and C0 represent the initial Euler angles of the base coordinate system O0, such as... Figure 3As shown; the base coordinate system O0 is a fixed coordinate system, which is the reference coordinate system for the robot base coordinate system, the robot machining coordinate system, and the pipe coordinate system. Its position will not change during the machining process, and it is the key coordinate system for subsequent machining trajectory calculation.

[0078] S12. Establish the robot base coordinate system: The origin O1 of the robot base coordinate system coincides with the center point of the base of the industrial six-degree-of-freedom robot 1. The base of the industrial six-degree-of-freedom robot 1 and the bottom sliding rail 3 are connected by a sliding plate. The point where the center point of the base of the industrial six-degree-of-freedom robot 1 coincides with the center of the sliding plate of the sliding rail 3 is the origin O1 of the robot base coordinate system. The positive direction of the Z-axis Z1 of the coordinate system is vertically upward and perpendicular to the ground. The positive direction of the X-axis X1 of the coordinate system is the same as the direction of the base coordinate system X0, and in this example, the direction is horizontal to the right. The direction of the Y-axis Y1 of the coordinate system is perpendicular to the X1O1Z1 plane, and the foot of the perpendicular intersects at point O1. The parameters of the robot base coordinate system O1 are (X1, Y1, Z1); where XYZ represent three-dimensional position points, describing the relative positional relationship between the robot base coordinate system O1 and the base coordinate system O0. The robot base coordinate system O1 is a motion coordinate system, and its initial position coincides with the base coordinate system O0, following the movement and change of the sliding rail 3.

[0079] S13. Establish the robot machining coordinate system: The origin O2 of the robot machining coordinate system is located at the center point of the arc of the bending mold clamping mechanism in the bending mechanism 2 at the end of the industrial six-degree-of-freedom robot 1, such as... Figure 4 As shown, the positive direction of the Z-axis Z2 of the coordinate system is in contact with the tangent surface of the circular mold of the bending mechanism 2; the X-axis X2 of the coordinate system coincides with the normal of the arc center of the clamping mechanism, and in this example, the direction is positive to the right; the Y-axis Y2 of the coordinate system is perpendicular to the X2O2Z2 plane, and the foot of the perpendicular intersects at point O2; the parameters of the robot processing coordinate system are (X2,Y2,Z2,A2,B2,C2), where XYZ represents the three-dimensional position point, describing the relative position relationship of the robot processing coordinate system O2 with respect to the base coordinate system O0, and A2,B2,C2 represent the rotation angles around the base coordinate system O0 in the X, Y, and Z directions; the robot processing coordinate system O2 is a motion coordinate system, which changes during the processing according to the motion of the sliding rail 3 and the joint motion of the industrial six-degree-of-freedom robot 1. The control accuracy of this motion trajectory determines the quality of the finished product after the pipe is bent, which is the key point of the processing trajectory calculation in this invention;

[0080] S14. Establish the pipe fitting coordinate system: The origin O3 of the pipe fitting coordinate system is located at the center point of the arc of the clamping mechanism of the pipe fitting holder 4. The positive direction of the Z-axis Z3 of the coordinate system is in contact with the tangential surface of the clamping mold and faces upward; the positive direction of the X-axis X2 of the coordinate system coincides with the center normal of the arc surface of the clamping mechanism, and in this example, the direction is horizontal to the right; the positive direction of the Y-axis Y3 of the coordinate system is perpendicular to the X3O3Z3 plane, and the foot of the perpendicular intersects at point O3; the pipe fitting coordinate system O3 is a fixed coordinate system, and its position will not change during the processing. The coordinate system parameters are (X3,Y3,Z3), where XYZ describes the three-dimensional position point and describes the relative position relationship of the pipe fitting coordinate system O3 with respect to the base coordinate system O0. Through this position information, combined with the processing length of the pipe fitting, the starting point position of the processing can be determined, which is convenient for obtaining the subsequent processing trajectory parameters;

[0081] II. Taking the M-type tube as an example, such as Figure 5 As shown, the machining trajectory planning steps include the following steps:

[0082] S21. Establish a 3D model of the pipe fitting: Based on the origin O2 of the robot machining coordinate system O2 of the M-shaped pipe and the starting point N0(X) of the pipe fitting bend. 20 ,Y 20 Z 20 A 20 B 20 C 20 The coordinate system X-axis (X2) points towards the pipe, the coordinate system Z-axis (Z2) points vertically upward, and the coordinate system Y-axis (Y2) is perpendicular to the X2O2Z2 plane, with the feet of the perpendiculars intersecting at point O2. During the processing, the pipe bending mechanism 2 and the robot's processing coordinate system O2 move along the direction of the pipe, with its X-axis data changing constantly, while the Y-axis and Z-axis coordinates remain unchanged. Upon reaching the processing point, the pipe bending mechanism 2 is rotated by the industrial six-degree-of-freedom robot 1, causing it to rotate around the X-axis (X2) of the processing coordinate system O2, thus achieving three-dimensional pipe bending.

[0083] S22. Robot machining coordinate system calibration based on the 3D model of the pipe fitting: align the origin O2 of the robot machining coordinate system with the starting point of the pipe fitting machining, i.e., one end point, so that the positive direction of the X-axis X2 of the coordinate system points to the direction of the pipe fitting, the positive direction of the Z-axis Z2 of the coordinate system is vertically upward, and the Y-axis Y2 of the coordinate system is perpendicular to the X2O2Z2 plane, with the foot of the perpendicular intersecting at point O2.

[0084] S23. Calculation of pipe fitting machining parameters:

[0085] (1) The starting point of the first bend, N1(X) 21 ,Y 21 Z 21 A 21 B 21 C 21 );

[0086] Among them, X 21 =X 20 +L1;Y 21 =Y 20 Z 21 =Z 20 A 21 =A 20 B 21 =B 20 C 21 =C 20 ;

[0087] L1 is the feed rate for the first stage of processing;

[0088] The first bend angle is θ1(0,θ1);

[0089] After the processing is completed, the rotating shaft of the bending mechanism 2 returns to the center, the bending angle θ1 is zeroed, and then the next bending process is carried out.

[0090] (2) The starting point of the second bend, N2(X) 22 ,Y 22 Z 22 A 22 B 22 C 22 );

[0091] Among them, X 22 =X 21 +L2=X 20 +L1+L2;Y 22 =Y 21 =Y 20 Z 22 =Z 21 =Z 20 A 22 =A 21 ± α 21 =A 20 ± α 21 B 22 =B 21 =B 20 C 22 =C 21 =C 20 ;

[0092] L2 is the feed rate for the second stage of processing;

[0093] α 21 It represents the rotation angle of the pipe bending mechanism 2 around the X-axis X2 direction of the machining coordinate system O2. Clockwise rotation around the pipe is positive, and counterclockwise rotation is negative.

[0094] The angle of the second bend is θ2(0,θ2);

[0095] (3) The starting point of the third bend is N3(X) 23 ,Y 23 Z 23 A 23 B 23 C 23 );

[0096] Among them, X 23 =X 22 +L3=X 21 +L2+L3=X 20 +L1+L2+L3;Y 23 =Y 22 =Y 21 =Y 20 Z 23 =Z 22 =Z 21 =Z 20 A 23 =A 22 ± α 22 ± α 21 =A 21 ± α 22 ± α 21 =A 20 ± α 22 ± α 21 B 23 =B 22 =B 21 =B 20 C 23 =C 22 =C 21 =C 20 ;

[0097] L2 is the feed rate for the second stage of processing;

[0098] α 22 It represents the rotation angle of the pipe bending mechanism 2 around the X-axis X2 direction of the machining coordinate system O2. Clockwise rotation around the pipe is positive, and counterclockwise rotation is negative.

[0099] The second bend angle is θ3(0,θ3);

[0100] III. The steps for bending the pipe are as follows:

[0101] (1) N0(X) 20 ,Y 20Z 20 A 20 B 20 C 20 ) to N1(X 21 ,Y 21 Z 21 A 21 B 21 C 21 The processing trajectory Traj N01 ;

[0102] Traj N01 =(X N01 (t),Y N01 (t),Z N01 (t),A N01 (t),B N01 (t),C N01 (t));

[0103] in:

[0104] X N01 (t)=X 20 +(X 21 -X 20 )*t / T;

[0105] Y N01 (t)=Y 20 +(Y 21 -Y 20 )*t / T;

[0106] Z N01 (t)=Z 20 +(Z 21 -Z 20 )*t / T;

[0107] t is the current time, T is the total time required for operation, and the displacement of this trajectory is calculated based on the ratio of the moving distance to the time. If the pipe bending mechanism 2 moves horizontally along the pipe fitting in the X-axis X2 direction of the machining coordinate system O2 with a speed of V... X ,but

[0108] ;

[0109] The processing trajectory Traj from N0 to N1 N01 Expressed as a function of velocity and time, as follows:

[0110] ;

[0111] ;

[0112] ;

[0113] If the rotational speed of the bending shaft of the pipe bending mechanism 2 is w 弯 Its rotation trajectory is expressed as a function of angle and time, as follows:

[0114] A N01 (t)=A 20 +w 弯 *t*sign(A 21 -A 20 );

[0115] B N01 (t)=B 20 +w 弯 *t*sign(B 21 -B 20 );

[0116] C N01 (t)=C 20 +w 弯 *t*sign(C 21 -C 20 );

[0117] (2) N1(X) 21 ,Y 21 Z 21 A 21 B 21 C 21 ) to N2(X 22 ,Y 22 Z 22 A 22 B 22 C 22 The processing trajectory Traj N12 ;

[0118] Traj N12 =(X N12 (t),Y N12 (t),Z N12 (t),A N12 (t),B N12 (t),C N12 (t));

[0119] ;

[0120] ;

[0121] ;

[0122] A N12 (t)=A 21 +w 弯 *t*sign(A22 -A 21 )

[0123] B N12 B(t)=B 21 +w 弯 *t*sign(B 22 -B 21 )

[0124] C N12 C(t)=C 21 +w 弯 *t*sign(C 22 -C 21 )

[0125] (3) N2(X 22 , Y 22 , Z 22 , A 22 , B 22 , C 22 ) to N3(X 23 , Y 23 , Z 23 , A 23 , B 23 , C 23 ) of the machining trajectory Traj N23 ;

[0126] Traj N23 =(X N23 (t), Y N23 (t), Z N23 (t), A N23 (t), B N23 (t), C N23 (t));

[0127] ;

[0128] ;

[0129] ;

[0130] A N23 A(t)=A 22 +w 弯 *t*sign(A 23 -A 22 )

[0131] B N23 B(t)=B 22 +w 弯 *t*sign(B 23 -B 22 )

[0132] C N23 (t)=C 22 +w 弯 *t*sign(C 23 -C 22 );

[0133] IV. The trajectory optimization steps include the following:

[0134] (1) Optimization of bend spacing. For N0(X) 20 ,Y 20 Z 20 A 20 B 20 C 20 ) to N1(X 21 ,Y 21 Z 21 A 21 B 21 C 21 The processing trajectory Traj N01 Its length is L1. The pipe bending mechanism 2 is driven by the joints of the industrial six-degree-of-freedom robot 1 to move horizontally along the pipe in the X-axis X2 direction of the machining coordinate system O2 at a speed of V. X Because the industrial six-degree-of-freedom robot 1 has a linear guide rail 3 on its base, the robot moves on the linear guide rail 3 with a relative velocity V with respect to the base coordinate system O0. 轨 Therefore, its total speed

[0135] V 总 =V X +V 轨 ;

[0136] Its trajectory can be optimized as follows:

[0137] ;

[0138] ;

[0139] ;

[0140] Its bend spacing It can be shortened to:

[0141] ;

[0142] (2) Head angle calculation optimization. The initial posture of the end-effector bending mechanism 2 of the mobile pipe bending robot is (A 20 B 20 C 20 The starting attitude of the first bend is (A) 21 B 21 C 21),in:

[0143] A 21 =A 20 ;

[0144] That is, the first bend maintains its initial posture;

[0145] A 22 =A 21 ± α 21 ;

[0146] in α 21 The angle of rotation of the pipe bending mechanism 2 around the X-axis (X2 direction) of the machining coordinate system O2;

[0147] ;

[0148] ;

[0149] Where N is the starting point of the arc of the bend, N ’ For the endpoint of the curved pipe, such as Figure 6 As shown;

[0150] For surface N0N1N2 ’ The normal vector components;

[0151] For surfaces N1N2N3 ’ The normal vector components;

[0152] There are many specific ways to implement this invention. The above description is only a preferred embodiment of this invention. It should be noted that for those skilled in the art, several improvements can be made without departing from the principle of this invention, and these improvements should also be considered within the scope of protection of this invention.

Claims

1. A pipe bending processing method using a mobile pipe bending robot, characterized in that: This includes steps such as coordinate system establishment, machining trajectory planning, pipe bending execution, and trajectory optimization. The steps for establishing the coordinate system are as follows: S11. Establish the base coordinate system: The origin O0 of the base coordinate system is set at the center of the linear guide rail at the bottom of the robot. The positive direction of the Z-axis Z0 is vertically upward and perpendicular to the ground. The positive direction of the X-axis X0 is determined based on the right-hand rule. The Y-axis Y0 is perpendicular to the X0O0Z0 plane, with the foot of the perpendicular intersecting at point O0. The parameters of the base coordinate system are (X0, Y0, Z0, A0, B0, C0), where A0, B0, and C0 represent the initial Euler angles of the base coordinate system O0, A0 corresponds to the rotation angle around the X-axis, B0 corresponds to the rotation angle around the Y-axis, and C0 corresponds to the rotation angle around the Z-axis. S12. Establish the robot's base coordinate system: The origin O1 of the robot's base coordinate system is located at the center point of the six-degree-of-freedom robot's base; the positive direction of the Z-axis Z1 is vertically upward and perpendicular to the ground; the positive direction of the X-axis X1 is the same as the X0 direction of the base coordinate system; the Y-axis Y1 is perpendicular to the X1O1Z1 plane, with the foot of the perpendicular intersecting at point O1; the initial position of the coordinate system coincides with the base coordinate system, and the parameters are (X1, Y1, Z1). S13. Establish the robot machining coordinate system: The origin O2 of the robot machining coordinate system is set at the center point of the arc of the bending and clamping mechanism at the end of the robot. The positive direction of the Z-axis Z2 of the coordinate system is in contact with the tangent surface of the circular mold and faces upward. The X-axis X2 of the coordinate system coincides with the normal to the center of the arc of the clamping mechanism, and its direction is positive to the right. The Y-axis Y2 of the coordinate system is perpendicular to the X2O2Z2 plane, and the foot of the perpendicular intersects at point O2. The parameters of the robot machining coordinate system are (X2, Y2, Z2, A2, B2, C2), where A2, B2, and C2 represent the rotation angles around the X, Y, and Z axes of the base coordinate system O0. S14. Establish the pipe fitting coordinate system: The origin O3 of the pipe fitting coordinate system is set at the center point of the arc of the clamping mechanism of the clamping device. The positive direction of the Z-axis Z3 of the coordinate system is in contact with the tangential surface of the clamping mold and faces upward. The positive direction of the X-axis X3 of the coordinate system coincides with the center normal of the arc surface of the clamping mechanism. The positive direction of the Y-axis Y3 of the coordinate system is perpendicular to the X3O3Z3 plane, and the foot of the perpendicular intersects at point O3. The parameters of the pipe fitting coordinate system are (X3, Y3, Z3). The processing trajectory planning steps are as follows: S21. Establish a 3D model of the pipe fitting: Determine the processing parameters of the pipe fitting, including the bending angle of each bend, the position of the starting point of the bend, and the posture angle at that position; S22. Robot machining coordinate system calibration based on the 3D model of the pipe fitting: align the origin O2 of the robot machining coordinate system with the starting point of the pipe fitting machining, i.e., one end point, so that the positive direction of the X-axis X2 of the coordinate system points to the direction of the pipe fitting, the positive direction of the Z-axis Z2 of the coordinate system is vertically upward, and the Y-axis Y2 of the coordinate system is perpendicular to the X2O2Z2 plane, with the foot of the perpendicular intersecting at point O2. S23. Calculation of pipe fitting machining parameters: Pipe fitting processing starting point position N0(X) 20 Y 20 Z 20 A 20 B 20 C 20 ); The starting point of the first bend is N1(X) 21 Y 21 Z 21 A 21 B 21 C 21 ); Among them, X 21 = X 20 + L1; Y 21 = Y 20 ; Z 21 = Z 20 ; A 21 = A 20 ; B 21 = B 20 ; C 21 = C 20 ; L1 is the distance the first bend starting point N1 moves relative to the pipe fitting processing starting point N0 about the X-axis X2. The first bend angle is θ1(0, θ1); The starting point of the second bend is N2(X) 22 Y 22 Z 22 A 22 B 22 C 22 ); Among them, X 22 = X 21 + L2 = X 20 + L1 + L2; Y 22 = Y 21 = Y 20 ; Z 22 = Z 21 = Z 20 ; A 22 = A 21 ± ∆α 21 = A 20 ± ∆α 21 ; B 22 = B 21 = B 20 ; C 22 = C 21 = C 20 ; L2 is the distance that the starting point N2 of the second curve moves relative to the starting point N1 of the first curve about the X-axis X2. ∆α 21 This is the angle at which the head rotates around the pipe during the second bend; The second bend angle is θ2(0, θ2); The starting point of the nth bend is N. n (X 2n Y 2n Z 2n A 2n B 2n C 2n ); where, X 2n = X 20 + ; Y 2n = Y 2(n-1) = … = Y 21 = Y 20 ; Z 2n = Z 2(n-1) = … = Z 21 = Z 20 ; A 2n = A 2(n-1) ± ∆α 2(n-1) ; B 2n = B 2(n-1) = … = B 21 = B 20 ; C 2n = C 2(n-1) = … = C 21 = C 20 ; Where ∆α 2(n-1) This represents the angle at which the head rotates around the pipe fitting during the nth bend. The steps for bending the pipe are as follows: The processing trajectory Traj has the starting point N of each bend as the discontinuity point. The robot first moves to the discontinuity point of the trajectory to perform the pipe bending operation. After the processing of that bend is completed, it continues to the next segment of the trajectory. From the starting point of pipe fitting processing to the starting point of the first bend Traj N01 =(X N01 (t),Y N01 (t),Z N01 (t),A N01 (t),B N01 (t),C N01 (t)) in: X N01 (t)=X 20 +(X 21 -X 20 )*t / T AND N01 (t)=Y 20 +(And 21 -AND 20 )*t / T Z N01 (t)=Z 20 +(Z 21 -Z 20 )*t / T ； Where t represents the variable of the function, i.e., time; T represents the total time required for the movement; Therefore, we can conclude that: ； ； ； Where V X This indicates the horizontal velocity along the X-axis (X2 direction); In the formula: A N01 (t)=A 20 +w 弯 *t*sign(A 21 -A 20 ) B N01 (t)=B 20 +w 弯 *t*sign(B 21 -B 20 ) C N01 (t)=C 20 +w 弯 *t*sign(C 21 -C 20 ) Among them, w 弯 This indicates the rotational speed of the bending shaft in the pipe bending mechanism; Pipe fitting machining trajectory segment n Traj N(n-1)(n) =(X N(n-1)(n) (t),Y N(n-1)(n) (t),Z N(n-1)(n) (t),A N(n-1)(n) (t),B N(n-1)(n) (t),C N(n-1)(n) (t)) in: ； ； ； X 2(n-1)(n) (t)=X 2(n-1)(n) +(X 2(n-1) -X 20 )*t / T AND 2(n-1)(n) (t)=Y 2(n-1)(n) +(And 2(n-1) -AND 20 )*t / T Z 2(n-1)(n) (t)=Z 2(n-1)(n) +(Z 21 -Z 20 )*t / T A N(n-1)(n) (t)=A 2(n-1) +w 弯 *t*sign(A 2(n-1) -A 2(n) ) B N(n-1)(n) (t)=B 2(n-1) +w 弯 *t*sign(B 2(n-1) -B 2(n) ) C N(n-1)(n) (t)=C 2(n-1) +w 弯 *t*sign(C 2(n-1) -C 2(n) ); The trajectory optimization steps are as follows: (1) Optimization of pipe bend spacing: The horizontal movement speed of the mobile robot end relative to the robot base is V1, and the movement speed of the robot base relative to the base coordinate system on the straight rail is V2; for the base coordinate system O0 and the pipe coordinate system O3, the sum of the horizontal movement speed of the robot is (V1+V2). For each bend spacing, the bend spacing is... It can be shortened to ； (2) Head angle calculation optimization: The initial posture of the end effector head of the mobile robot is (A0, B0, C0). The posture at the starting point of the first bend remains unchanged. Starting from the second bend, the head angle is calculated according to the pipe processing parameters. The expression is as follows: A 21 =A 20 n=1; A 2n =A 2(n-1) ±∆α 2(n-1) n>1; ； ∆α represents the angle value of the machine head rotating around the pipe, N is the starting point of the bend arc, and N' is the ending point of the bend arc. During the processing, after completing the bend, the robot uses this posture as the initial posture to calculate the rotation angle of the next bend.

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