Planning Method for Rectangular Laser Welding Trajectory and Energy Following and Motion Controller

Abstract

The rectangular laser welding trajectory and energy following planning method provided by the present invention forms a first rectangular trajectory according to dimensional parameters, an S-curve planning algorithm and a uniform speed planning algorithm, performs laser energy following planning on the first rectangular trajectory to form a first energy following curve, and adjusts the first X-axis position trajectory, the first Y-axis position trajectory and the first energy following curve according to a phase shift algorithm to generate a second rectangular trajectory, and the second rectangular trajectory is the final welding trajectory. The present invention uses the S-curve planning algorithm and the uniform speed planning algorithm for rectangular welding path planning and energy following synchronous control, has lower complexity and stronger flexibility, and can flexibly and conveniently adjust the energy following curve under different working conditions such as acceleration section, deceleration section, uniform speed section, low speed section and high speed section welding, so that the overall welding is uniform and consistent, and effectively improves the overall welding quality.

Description

Technical Field

[0001] The present invention relates to the technical field of laser welding, and particularly to a method for planning a rectangular laser welding trajectory and energy following, and a motion controller. Background Art

[0002] With the popularization of automated production, laser welding, as an important non-contact welding method, has been widely applied in industrial production. It realizes the atomic bonding between two separated products by focusing a high-energy laser beam on the surface or inside of the product to be processed. Due to the significant advantages of laser welding, such as a small heat-affected zone, non-contact processing, and high processing efficiency, it has been widely used in various industries. In the field of new energy lithium batteries, laser welding technology has been widely applied to the welding of tab ears, battery cell casings, sealing nails, flexible connections, explosion-proof valves, and battery modules, etc.

[0003] Currently, the widely used laser welding technology in the field is position synchronous output (PSO) laser welding technology. This technology judges whether the current position reaches the set position by receiving the current position of the welding head fed back by the encoder. When the welding head reaches the set position, a laser control signal is sent to the laser to control the laser to output laser at the set position. In this method, the same laser energy is used for welding regardless of the situation, ignoring the differences in welding speeds in the acceleration, deceleration, low-speed, or high-speed sections, which should apply to different laser energies, resulting in uneven welding. Moreover, there is a response time difference between the laser controller and the axis controller, and it is difficult to achieve synchronous control of the laser and the welding trajectory, thus leading to a decline in the overall welding quality. Summary of the Invention

[0004] The present invention proposes a method for planning a rectangular laser welding trajectory and energy following for the above problems, and the overall welding quality can be effectively improved through this method.

[0005] According to a first aspect, in one embodiment, a method for planning a rectangular laser welding trajectory and energy following is provided, including: obtaining a laser welding task set by a user, where the laser welding task includes dimension parameters and shape parameters, the shape parameters include a frame rectangle, a starting weld point arc, and an ending weld point arc, and the four corners of the frame rectangle are rounded; establishing a coordinate system based on the frame rectangle, where the X-axis direction of the coordinate system is the direction where the long side of the frame rectangle is located, and the Y-axis direction of the coordinate system is the direction where the short side of the frame rectangle is located; calculating, according to the S-curve planning algorithm and the dimension parameters, multiple sets of S-curve position values corresponding to the rectangular straight sides, the starting weld point arc, and the ending weld point arc of the frame rectangle respectively, each set of S-curve position values corresponding to an S-curve, and each set of S-curve position values including S-curve position sub-values corresponding to multiple first trajectory points, and a single S-curve position sub-value corresponding to a single first trajectory point; obtaining the first X-axis position, the first Y-axis position, and the first composite axis displacement sub-value of each first trajectory point according to each S-curve position sub-value; calculating, according to the uniform speed planning algorithm and a preset interpolation period, multiple sets of second composite axis displacement values corresponding to the rounded corners of the frame rectangle respectively, each set of second composite axis displacement values including multiple second composite axis displacement sub-values corresponding to second trajectory points; obtaining the second X-axis position and the second Y-axis position of each second trajectory point according to each second composite axis displacement sub-value; generating a first rectangular trajectory corresponding to the laser welding task according to the first X-axis positions and the first Y-axis positions of all the first trajectory points, and the second X-axis positions and the second Y-axis positions of all the second trajectory points, where the first matrix trajectory includes a first X-axis position trajectory and a first Y-axis position trajectory; obtaining a first energy value corresponding to each first trajectory point according to the energy following planning algorithm and each first composite axis displacement sub-value; obtaining a second energy value corresponding to each second trajectory point according to the energy following planning algorithm and each second composite axis displacement sub-value; performing laser energy following planning on the first rectangular trajectory according to all the first energy values and all the second energy values to generate a first energy following curve, and respectively adjusting the first X-axis position trajectory, the first Y-axis position trajectory, and the first energy following curve according to the phase shift algorithm to obtain a second X-axis position trajectory, a second Y-axis position trajectory, and a second energy following curve; generating a second rectangular trajectory according to the second X-axis position trajectory, the second Y-axis position trajectory, and the second energy following curve.

[0006] In some embodiments, it further includes: performing connection speed planning on the connection points between the starting weld point arc and each rectangular straight side, the connection points between the ending weld point arc and the frame rectangle, and the connection points between each rounded corner of the frame rectangle and each rectangular straight side.

[0007] In some embodiments, the method for planning the connection speed of the connection points between the starting weld arc and each of the rectangular straight edges, the connection points between the ending weld arc and the rectangular straight edges, the connection points between the ending weld arc and the frame rectangle, and the connection points between each rounded corner of the frame rectangle and each of the rectangular straight edges includes: when the starting weld arc or the ending weld arc or the rounded corner of the frame rectangle is connected to the rectangular straight edge, making the connection speed of the connection point be the linear speed of the end point of the rounded corner of the frame rectangle, and the radii of the starting weld arc, the ending weld arc, and the rounded corners of the frame rectangle are equal; when the rectangular straight edge is connected to the starting weld arc or the ending weld arc or the rounded corner of the frame rectangle, making the connection speed of the connection point be the end point speed of the rectangular straight edge, and the end point speed of the rectangular straight edge is obtained according to the uniform speed planning algorithm. In some embodiments, the laser welding task further includes motion parameters, and the S-curve planning algorithm includes: according to the motion parameters, calculating the values of each time period corresponding to the S-curve, and the time period of the S-curve includes a first uniform speed time period; according to the motion parameters, verifying whether the value of the first uniform speed time period exists; if it exists, then calculating a second uniform speed time period, and rounding up the interpolation time of each time period of the S-curve so that the interpolation time of each time period is an integer multiple of a preset interpolation period, where the interpolation time of each time period corresponds to each time period of the S-curve; if it does not exist, then rounding up the interpolation time of each time period of the S-curve so that the interpolation time of each time period is an integer multiple of a preset interpolation period, and the interpolation time of each time period corresponds to each time period of the S-curve; according to the adjusted interpolation times, calculating the displacement values of each time period; and generating a set of S-curve position values according to the displacement values of all time periods.

[0008] In some embodiments, the uniform speed planning algorithm includes: according to a preset acceleration derivation method and angular velocity derivation method, calculating the angular velocity and linear speed of each of the second trajectory points; and calculating a corresponding set of second combined axis displacement values according to the angular velocity, the linear speed, the interpolation period, and the time point of each of the second trajectory points.

[0009] In some embodiments, the method for obtaining the first X-axis position and the first Y-axis position of each first trajectory point according to each S-curve position sub-value includes: the first X-axis position of the first trajectory point corresponding to the long side of the frame rectangle is equal to the S-curve position sub-value of the first trajectory point, and its first Y-axis position is equal to zero; the first X-axis position of the first trajectory point corresponding to the short side of the frame rectangle is equal to zero, and its first Y-axis position is equal to the S-curve position sub-value of the first trajectory point.

[0010] In some embodiments, the method for obtaining the second X-axis position and the second Y-axis position of each second trajectory point according to each second composite axis displacement sub-value includes: calculating the angular velocity of each second trajectory point according to the second composite axis displacement sub-value of each second trajectory point; and calculating the second X-axis position and the second Y-axis position of each second trajectory point according to the angular velocity of each second trajectory point and a preset angle value.

[0011] In some embodiments, the parameters of the laser welding task further include energy parameters, and the energy following planning algorithm includes: calculating, according to each of the first composite axis displacement sub-values, a first composite axis speed interpolation point corresponding to each first trajectory point; calculating, according to each of the second composite axis displacement sub-values, a second composite axis speed interpolation point corresponding to each second trajectory point; and generating a first energy following curve according to the energy parameters, all the first composite axis speed interpolation points, all the first composite axis speed interpolation points, and a laser energy following model.

[0012] In some embodiments, the phase shift algorithm includes: processing a preset offset time to respectively obtain an integer part and a decimal part of the offset time; and calculating, according to the integer part of the offset time, the decimal part of the offset time, and the first X-axis position trajectory / the first Y-axis position trajectory / the first energy following curve, a second X-axis position trajectory / a second Y-axis position trajectory / a second energy following curve, respectively.

[0013] According to a second aspect, a motion controller for a laser welding device provided in an embodiment includes: an X-axis motion controller, a Y-axis motion controller, and a laser controller; the X-axis motion controller is configured to receive the second X-axis position trajectory obtained by using the foregoing planning method to control the operation of the X-axis motor of the laser welding device; the Y-axis motion controller is configured to receive the second Y-axis position trajectory obtained by using the foregoing planning method to control the operation of the Y-axis motor of the laser welding device; and the laser motion controller is configured to receive the second energy following curve information obtained by using the foregoing planning method to control the operation of the laser controller of the laser welding device.

[0014] According to the rectangular laser welding trajectory and energy following planning method of the above embodiments, by applying the S-shaped curve planning algorithm and the uniform speed planning algorithm to the rectangular welding path planning and energy following synchronous control, compared with methods such as the currently widely used position synchronous output (PSO), it has lower complexity and stronger flexibility. In the case of welding under different working conditions such as the acceleration section, deceleration section, uniform speed section, low speed section, and high speed section, it can more flexibly and conveniently adjust the energy following curve, making the overall welding uniform and consistent, and effectively improving the overall welding quality.

[0015] Furthermore, the method provided by the present invention also has the following advantages:

[0016] In the first rectangular trajectory planning, speed planning is carried out for the entire welding shape including each connection point. Welding is performed based on the first rectangular trajectory, and the welding equipment runs at a constant speed during the entire welding process, which can reduce the vibration of the welding machine, effectively reduce the position fluctuation during welding, and improve the welding quality.

[0017] During the generation of the energy following curve, by adopting piecewise adjustable parameters, each segment of energy can be well controlled, and each point on the energy following curve can be accurately controlled, making the parameter setting more accurate and flexible.

[0018] The algorithm of phase shift can modify the phases of the X-axis position trajectory, Y-axis position trajectory, and energy following curve, so that the control system of the entire welding equipment is synchronized, reducing the response time difference during welding, avoiding the laser from emitting light ahead or lagging, and thus improving the welding quality. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 is a flowchart of a method for planning a rectangular laser welding trajectory and energy following;

[0020] Figure 2 is a schematic diagram of a rectangular welding shape;

[0021] Figure 3 is a schematic diagram of an S-shaped curve;

[0022] Figure 4 is a flowchart of an S-shaped curve planning algorithm of an embodiment;

[0023] Figure 5 is a flowchart of a method for obtaining the first X-axis position and the first Y-axis position of each first trajectory point according to each S-shaped curve position sub-value of an embodiment;

[0024] Figure 6 is a flowchart of a constant speed planning algorithm of an embodiment;

[0025] Figure 7 is a flowchart of a method for obtaining the second X-axis position and the second Y-axis position of each second trajectory point according to each second combined axis displacement sub-value of an embodiment;

[0026] Figure 8 is a flowchart of an energy following planning algorithm of an embodiment;

[0027] Figure 9 is a schematic diagram of the position where the K-value coefficient corresponding trajectory is located in an embodiment;

[0028] Figure 10 is a flowchart of a phase shift algorithm of an embodiment;

[0029] Figure 11 A flowchart of a method for planning the connection speed of the connection points between the arc of the starting welding point and the rectangular straight edge, the connection points between the arc of the ending welding point and the rectangular straight edge, and the connection points between each rounded corner of the frame rectangle and the respective rectangular straight edges in an embodiment. Detailed implementation manners

[0030] The present invention will be further described in detail below in conjunction with the accompanying drawings through specific implementation manners. Similar elements in different implementation manners are labeled with related similar element numbers. In the following implementation manners, many details are described to enable a better understanding of the present application. However, those skilled in the art can easily recognize that some of the features can be omitted in different situations, or can be replaced by other elements, materials, or methods. In some cases, some operations related to the present application are not shown or described in the specification to avoid overwhelming the core part of the present application with excessive description. For those skilled in the art, it is not necessary to describe these related operations in detail, and they can fully understand the related operations based on the description in the specification and general technical knowledge in the art.

[0031] In addition, the features, operations, or characteristics described in the specification can be combined in any appropriate manner to form various implementation manners. At the same time, the steps or actions in the method description can also be reordered or adjusted in a manner obvious to those skilled in the art. Therefore, the various sequences in the specification and drawings are only for clearly describing a certain embodiment and do not mean a necessary sequence, unless it is stated that a certain sequence must be followed.

[0032] The serial numbers assigned to the components herein, such as "first", "second", etc., are only used to distinguish the described objects and do not have any sequential or technical meaning.

[0033] In the position synchronous output (PSO) laser welding technology, when it is recognized that the current position of the welding head reaches the set position, a laser control signal is sent to the laser to control the laser to output laser at the set position. This method uses the same laser energy for welding regardless of the situation, ignoring the differences in welding speed in the acceleration section, deceleration section, low-speed section, or high-speed section, which should be applicable to different laser energies, resulting in uneven welding. Moreover, there is a response time difference between the laser controller and the axis controller, and it is difficult to achieve synchronous control of the laser and the welding trajectory, thus leading to a decline in the overall welding quality.

[0034] In an embodiment of the present invention, a first rectangular trajectory is formed according to the parameters of the laser welding task set by the user, the S-shaped curve planning algorithm, and the uniform speed planning algorithm, and laser energy following planning is performed on the first rectangular trajectory to form a first energy following curve; then, according to the phase shift algorithm, the first X-axis position trajectory, the first Y-axis position trajectory, and the first energy following curve are adjusted to generate a final welding trajectory. In the case of welding under different working conditions such as the acceleration section, the deceleration section, the uniform speed section, the low speed section, and the high speed section, the energy following curve can be adjusted more flexibly and conveniently, so that the overall welding is uniform and consistent, and the overall welding quality is effectively improved.

[0035] Please refer to Figure 1 , an embodiment of the present invention provides a method for planning a rectangular laser welding trajectory and energy following, including:

[0036] S10: Obtain the laser welding task set by the user, where the laser welding task includes dimension parameters and shape parameters, and the shape parameters include a frame rectangle, a starting weld point arc, and an ending weld point arc, and the four corners of the frame rectangle are rounded corners.

[0037] In some embodiments, as Figure 2 shown, the dimension parameters include the length values of the long sides (L1 and L3) and short sides (L2 and L4) of the frame rectangle, the angles and radii of the rounded corners R1, R2, R3, R4 of the frame rectangle, as well as the angles and radii of the starting weld point arc and the ending weld point arc, etc., and also include the relative distance Start_L, which is used to determine the position of point B. According to the dimension parameters of the laser welding task set by the user, the corresponding welding shape can be generated, and the welding shape includes a frame rectangle, a starting weld point arc, and an ending weld point arc, and the four corners of the frame rectangle are rounded corners. During welding, start welding from point C of the starting weld point arc, pass through point B along the arc section, then weld in the direction of point A, but do not pass through point A, move along the R1 arc trajectory, then pass through L2-R2-L3-R3-L4-R4-L1 in sequence and return to point B, and finally run to the end point D of the ending weld point arc section to terminate.

[0038] S20: Establish a coordinate system according to the frame rectangle, where the X-axis direction of the coordinate system is the direction where the long side of the frame rectangle is located, and the Y-axis direction of the coordinate system is the direction where the short side of the frame rectangle is located.

[0039] During application, in the moving XY platform used for laser welding, the moving directions of the X-axis and the Y-axis should be consistent with this direction. If the direction of a certain axis is inconsistent, the position trajectory of this axis needs to be reversed in the generated rectangular welding trajectory.

[0040] S30: Calculate multiple sets of S-curve position values corresponding to the straight sides of the frame rectangle, the starting welding point arc, and the ending welding point arc respectively according to the S-curve planning algorithm and the dimensional parameters. Each set of S-curve position values corresponds to an S-curve, and each set of S-curve position values includes S-curve position sub-values corresponding to multiple first trajectory points. A single S-curve position sub-value corresponds to a single first trajectory point. The first trajectory point is one of the trajectory points that can respectively form the long side / short side, the starting welding point arc, and the ending welding point arc of the frame rectangle. For example, the multiple first trajectory points corresponding to a set of S-curve position values can form the trajectory corresponding to the short side L4 ( Figure 2 as shown).

[0041] In some embodiments, the parameters of the laser welding task further include motion parameters, such as Figure 4 as shown, the S-curve planning algorithm includes:

[0042] S301: Calculate the values of each time period corresponding to the S-curve according to the motion parameters. The time period of the S-curve includes the first constant-speed time period.

[0043] In some embodiments, the motion parameters include the initial speed f s , the end speed f e , the maximum speed F, the interpolation period T S , the total path length L, the expected maximum acceleration A, the expected maximum deceleration D, and the expected jerk J, etc.

[0044] Such as Figure 3 as shown, in the S-curve planning, the planning process is divided into seven stages, where: T 1 section is the acceleration increasing time period of the acceleration section, T 2 section is the acceleration constant time period of the acceleration section, T 3 section is the acceleration decreasing time period of the acceleration section, T 4 section is the constant-speed time period, T 5 section is the acceleration increasing time period of the deceleration section, T 6 section is the acceleration constant time period of the deceleration section, T 7 section is the acceleration decreasing time period of the deceleration section, T 1 section to T 7 section is the time passed in each section during the interpolation of the seven stages. Among them, the relationship between T k and t k is as follows: Among them, k is the time point, t k is the time value at the k-th time point, T k is the time period value between the k-th time point and the k - 1-th time point. In this embodiment, the first constant-speed time period is the T 4 section.

[0045] According to variables such as the total length L of the interpolation path, the initial speed f s , the end speed f e and the maximum speed F, etc., variables such as the interpolation time and acceleration of each interpolation stage can be initialized and calculated. The S-shaped curve is fitted from the displacement values of the seven stages in the S-curve planning. The method of calculating the values of each time period corresponding to the S-shaped curve according to the motion parameters is the prior art in this field and will not be elaborated here.

[0046] S302: Verify whether the value of the first constant-speed time period exists according to the motion parameters.

[0047] In some embodiments, by verifying whether the jerk, acceleration, and deceleration parameters are reasonable, that is, whether they can meet the requirement of the total path length L, it is determined whether the constant-speed time period T 4 (i.e., the first constant-speed time period) exists.

[0048] The jerk J is calculated in the following manner 0 :

[0049]

[0050] Where: J 0 is the jerk, A is the expected maximum acceleration set by the user, D is the expected maximum deceleration set by the user, and T a is the jerk time (i.e., the calculated T 1 , T 3 , T 5 , T 7 section time, T 1 = T 3 = T 5 = T 7 ).

[0051] The maximum acceleration A 0 and the maximum deceleration D 0 are calculated in the following manner

[0052]

[0053]

[0054] Where sgn() is the sign function, A is the expected maximum acceleration set by the user, D is the expected maximum deceleration set by the user, f s is the initial speed set by the user, F is the maximum speed set by the user, and J 0 is the jerk.

[0055]

[0056] Where, fs The initial speed set for the user, F is the maximum speed set for the user, and f e is the end speed set for the user, and T 4 is the time value of the constant-speed time period, and J 1 is for T 2 the jerk value during the T 5 is for T 5 the jerk value during the time period, such that J = J 1 = J 5 , when the constant-speed time period T 4 = 0, L1 is less than the total path length L set by the user, that is, when T 4 = 0, there is no constant-speed time period.

[0057] S303: If it exists, calculate the second constant-speed time period, round up the interpolation time for each time period of the S-shaped curve so that the interpolation time for each time period is an integer multiple of the preset interpolation period, where the interpolation time for each time period corresponds to each time period of the S-shaped curve.

[0058] In application, when T 4 ≠ 0, that is, when there is a first constant-speed time period T 4 value, it is necessary to calculate and find the second constant-speed section T 41 value, and the calculation method of T 41 is: T 41 = (L - L1) / F, and the values of each parameter can refer to step S302.

[0059] S304: If it does not exist, round up the interpolation time for each time period of the S-shaped curve so that the interpolation time for each time period is an integer multiple of the preset interpolation period, and the interpolation time for each time period corresponds to each time period of the S-shaped curve.

[0060] In actual application, there will be cases where the interpolation time for each time period is not an integer, which greatly affects the interpolation accuracy. In this embodiment, the interpolation time for each time period is rounded up so that the interpolation time for each time period is an integer multiple of the preset interpolation period. The following is an example of adjusting the interpolation time for the T 1 section:

[0061] T 11 = ceil(T 1 / T S )

[0062] where ceil() is the ceiling function, T S is the interpolation period, T 1 is the interpolation time before rounding, and T 11 is the interpolation time after rounding.

[0063] S305: Calculate the displacement values for each time period based on the rounded interpolation times. The calculation method involved is an existing technique in the art and will not be elaborated here.

[0064] S306: Generate a set of S-curve position values based on the displacement values of all time periods.

[0065] In practical applications, for the convenience of subsequent step calls, the S-curve planning algorithm can be encapsulated into the following function interface:

[0066] [dis_on,count] = SCurvePlanNew(Dis,F,A,D,J,Ts,fs,fe)

[0067] Where SCurvePlanNew() is the function interface, and the input parameters are motion parameters, including: displacement Dis, maximum speed F, acceleration A, deceleration D, jerk J, interpolation period T S , starting speed f s , ending speed f e . The output parameters are the S-curve position value array dis_on() and the total number of S-curve position sub-values count. The S-curve position sub-values in dis_on() are the calculated displacement values for each time period.

[0068] S40: Obtain the first X-axis position, first Y-axis position, and first composite axis displacement sub-value of each first trajectory point according to each S-curve position sub-value.

[0069] In some embodiments, the method for obtaining the first X-axis position and first Y-axis position of each first trajectory point according to each S-curve position sub-value, as Figure 5 shown, includes:

[0070] S41: The first X-axis position of the first trajectory point corresponding to the long side of the frame rectangle is equal to the S-curve position sub-value of the first trajectory point, and its first Y-axis position is equal to zero. The specific calculation method is as follows:

[0071] Total_X(i) = dis_on(i)

[0072] Total_Y(i) = 0

[0073] S(i) = dis_on(i)

[0074] Where: dis_on() is an array of S-shaped curve position values, Total_X(i) is the first X-axis position of the S-shaped curve position sub-value of the i-th first trajectory point, Total_Y(i) is the second Y-axis position of the S-shaped curve position sub-value of the i-th first trajectory point, and S(i) is the first combined axis displacement sub-value of the i-th S-shaped curve position sub-value.

[0075] S42: The X-axis position of the first trajectory point corresponding to the short side of the frame rectangle is equal to zero, and its first Y-axis position is equal to the S-shaped curve position sub-value of this first trajectory point. The specific calculation method is as follows:

[0076] Total_X(i) = 0

[0077] Total_Y(i) = dis_on(i)

[0078] S(i) = dis_on(i)

[0079] Where: dis_on() is an array of S-shaped curve position values, the total number of S-shaped curve position sub-values in dis_on() is count, Total_X(i) is the first X-axis position of the S-shaped curve position sub-value of the i-th first trajectory point, Total_Y(i) is the first Y-axis position of the S-shaped curve position sub-value of the i-th first trajectory point, and S(i) is the first combined axis displacement sub-value of the i-th S-shaped curve position sub-value.

[0080] S50: According to the uniform motion planning algorithm and the preset interpolation period, calculate multiple groups of second combined axis displacement values corresponding to the rounded corners of the frame rectangle. Each group of second combined axis displacement values includes multiple second combined axis displacement sub-values corresponding to the second trajectory points. The second trajectory points are one of the trajectory points corresponding to the four rounded corners that can respectively form the frame rectangle. For example, the multiple second trajectory points corresponding to a group of second combined axis displacement values can form the trajectory corresponding to the rounded corner R1 ( Figure 2 as shown).

[0081] In some embodiments, as Figure 6 shown, the uniform motion planning algorithm includes:

[0082] S51: According to the preset acceleration derivation method and angular velocity derivation method, calculate the angular velocity and linear velocity of each second trajectory point.

[0083] In some embodiments, if the user gives the maximum acceleration a_max, then the X-axis acceleration and Y-axis acceleration should not be greater than a_max. The angular velocity derivation method is described below taking the Y-axis as an example:

[0084] At the start of the arc segments at the four corners of the frame rectangle, the acceleration reaches the set maximum acceleration a_max, then:

[0085] a = ((Total_Y(2 * th1) - Total_Y(th1)) / Ts - (Total_Y(th1) - 0) / T S ) / T S

[0086] That is: a = (R 1 * cos(th1) - R 1 * cos(th1) 2 ) / T S / T S <= a_max

[0087] where th1 is the angular velocity of the arc segment, T S is the interpolation period, a is the acceleration, R 1 is the angle of the fillet R1, and Total_Y() is the current relative position of the motor on the Y-axis.

[0088] When a = a_max, by solving the quadratic equation, the value of the angular velocity th1 can be obtained, and at the same time, the value of the linear velocity Ve1 can also be deduced. The calculation method of the linear velocity Ve1 is as follows: linear velocity = angular velocity * radius.

[0089] S52: Calculate a corresponding set of second composite axis displacement values according to the angular velocity, linear velocity, preset interpolation period, and time point of each second trajectory point.

[0090] In some embodiments, the arc segments at the four corners of the frame rectangle are uniformly planned, and the interpolation points at each time period are calculated, that is, the second composite axis displacement sub-values, and are calculated by the following method:

[0091] S(i) = Ve1 * T S * i

[0092] where S(i) is a set of current second composite axis displacement values of the arc segment, S(i) is exactly the arc length of the arc segment at each angular position, Ve1 is the linear velocity of the uniform motion of the arc segment, T S is the interpolation period, and i is the i-th time point.

[0093] S60: Obtain the second X-axis position and second Y-axis position of each second trajectory point according to each second composite axis displacement sub-value.

[0094] In some embodiments, the method for obtaining the second X-axis position and second Y-axis position of each second trajectory point according to each second composite axis displacement sub-value is as Figure 7 shown and includes:

[0095] S61: Calculate the angular velocity th1 of each second trajectory point based on the second composite axis displacement sub-value of each second trajectory point. The calculation method is as follows:

[0096] th1(i) = S(i) / R 1

[0097] Where: th1 is the angular velocity, and R 1 is the angle of the fillet R1.

[0098] S62: Calculate the second X-axis position and the second Y-axis position of each second trajectory point based on the angular velocity of each second trajectory point and a preset angle value. The calculation method is as follows:

[0099] Total_X(i) = R 1 *sin(th1(i))

[0100] Total_Y(i) = R 1 -R 1 *cos(th1(i))

[0101] Where: Total_X(i) is the current relative position of the motor on the X-axis of the i-th second trajectory point, and Total_Y(i) is the current relative position of the motor on the Y-axis of the i-th second trajectory point.

[0102] S70: Generate a first rectangular trajectory corresponding to the laser welding task based on the first X-axis position and the first Y-axis position of all first trajectory points, and the second X-axis position and the second Y-axis position of all second trajectory points. The first matrix trajectory includes a first X-axis position trajectory and a first Y-axis position trajectory.

[0103] Generate the trajectories corresponding to the rectangular straight edges, the starting weld point arc, and the ending weld point arc according to all first trajectory points respectively, and generate the trajectories corresponding to the four fillets of the frame rectangle according to all second trajectory points respectively. Then splice all the generated trajectories to obtain the first rectangular trajectory.

[0104] In some embodiments, the method for planning a rectangular laser welding trajectory and energy following provided by the present invention further includes: planning the connection speeds of the connection points between the starting weld point arc and each rectangular straight edge, the connection points between the ending weld point arc and the frame rectangle, and the connection points between each fillet of the frame rectangle and each rectangular straight edge.

[0105] In some embodiments, the method for planning the connection speeds of the connection points between the starting weld point arc and each rectangular straight edge, the connection points between the ending weld point arc and the frame rectangle, and the connection points between each fillet of the frame rectangle and each rectangular straight edge, as Figure 11 shown, includes:

[0106] S1201: When the starting solder joint arc or the ending solder joint arc or the rounded corner of the frame rectangle connects to the frame rectangle, the connection speed of the connection point is made to be the linear speed of the end point of the rounded corner of the frame rectangle, and the radii of the starting solder joint arc, the ending solder joint arc, and the rounded corner of the frame rectangle are equal;

[0107] S1202: When the straight side of the rectangle connects to the starting solder joint arc or the ending solder joint arc or the rounded corner of the frame rectangle, the connection speed of the connection point is made to be the end point speed of the straight side of the rectangle, and the end point speed of the straight side of the rectangle is obtained according to the uniform speed planning algorithm.

[0108] By performing speed planning on each connection point through the above method to obtain a suitable connection speed, the acceleration can be limited, further reducing the vibration of the welding machine and improving the welding quality.

[0109] The method provided by the present invention forms a first rectangular trajectory according to the dimension parameters, the S-curve planning algorithm, and the uniform speed planning algorithm. In the first rectangular trajectory planning, speed planning is performed on the entire welding shape including each connection point. Welding is performed based on the first rectangular trajectory, and the welding equipment runs at a uniform speed throughout the welding process, which can reduce the vibration of the welding machine, effectively reduce the position fluctuation during welding, and improve the welding quality.

[0110] S80: According to the energy following planning algorithm and each of the first combined axis displacement sub-values, a first energy value corresponding to each first trajectory point is obtained.

[0111] S90: According to the energy following planning algorithm and each of the second combined axis displacement sub-values, a second energy value corresponding to each second trajectory point is obtained.

[0112] In some embodiments, the parameters of the laser welding task further include energy parameters, such as Figure 8 As shown, the energy following planning algorithm involved in steps S80 and S90 includes:

[0113] S91: According to each first combined axis displacement sub-value, a first combined axis speed interpolation point corresponding to each first trajectory point is calculated, which is achieved through the following method:

[0114] V(1)=0;

[0115] for i = 2:Count

[0116] V(i)=(S(i)-S(i - 1)) / T S ;

[0117] End

[0118] wherein, V(i) is the first combined axis speed interpolation point (i.e., the speed value of the i-th first trajectory point), Count is the total number of first trajectory points, S(i) is the first combined axis displacement sub-value, and TS is the interpolation period.

[0119] S92: According to each second composite axis displacement sub-value, calculate the second composite axis velocity interpolation point corresponding to each second trajectory point. The implementation method is the same as that in step S91 and will not be elaborated here.

[0120] S93: Generate a first energy following curve according to the energy parameter, all the first composite axis velocity interpolation points, all the second composite axis velocity interpolation points, and the laser energy following model formula.

[0121] In some embodiments, substitute the first composite axis velocity interpolation point and the second composite axis velocity interpolation point into the laser energy following model formula respectively. The model formula can perform proportional scaling and translation processing on the curve; substitute each first trajectory point / each second trajectory point corresponding to the straight side and R corner (including the starting welding point arc, the ending welding point arc, and the four corners) of the first rectangular trajectory into the model separately, calculate each first energy value / each second energy value according to the known energy parameter, and then obtain the converted first energy following curve.

[0122] The energy following model formula for the long side and R corner (including the starting welding point arc, the ending welding point arc, and the four corners) of the first rectangular trajectory is as follows:

[0123] P[i] = P max -(V max -V[i])*K10 + Kn (1)

[0124] The energy following model formula for the short side of the first rectangular trajectory is as follows:

[0125] P[i] = (P max -(V max -V[i])*K10 - Pr)*Kn2 + Pr (2)

[0126] where, i is the i-th first trajectory point or second trajectory point; P[i] is the energy value array; P max is the total laser power, that is, the maximum energy; Pr is the energy value of the R corner; V max is the highest speed in the trajectory planning; V[i] is the current speed array of the composite axis; K10 is the energy parameter, which is an externally adjustable proportional coefficient, and the value range of K10 is from 0.5 to 1.5. The smaller the value of K10, the smaller the energy value; Kn is the energy parameter, which is an externally adjustable coefficient of K1-K2, K4-K6, K8-K9, and the value range is from -10 to 10. For example Figure 9As shown, K1-K2, K4-K6, and K8-K9 respectively correspond to the positions of each straight edge and rounded corner, and can individually adjust the energy of a certain section in the rectangular trajectory, and can be finely adjusted according to the welding process requirements; Kn2 is an energy parameter, which is an adjustable coefficient of external K3 and K7, corresponding to the two short sides of the frame rectangle, and the value range is from -10 to 10, and can be finely adjusted according to the welding process requirements; K11 is an energy parameter, which is the angular velocity proportionality coefficient of the starting welding point arc or the ending welding point arc, and the value range is from -10 to 10, and is finely adjusted according to the welding process requirements. Figure 9 The figure shows the position where the K value coefficient corresponds to the trajectory.

[0127] In the process of generating the energy following curve provided by the present invention, by using piecewise adjustable parameters, the energy of each section can be well controlled, and each point on the energy following curve can be accurately controlled, making its parameter setting more flexible and convenient.

[0128] S100: According to all the first energy values and all the second energy values, perform laser energy following planning for the first rectangular trajectory to generate a first energy following curve;

[0129] Through the energy following model in step S93, multiple groups of energy values P[i] corresponding to the long side, short side, and R corner (including the starting welding point arc, ending welding point arc, and four corners) of the first rectangular trajectory are obtained respectively. By splicing the multiple groups of energy values P[i], the first energy following curve of the first rectangular trajectory can be generated.

[0130] In the laser energy following planning of the first rectangular trajectory of the present invention, all the first energy values and all the second energy values are considered, making the laser energy following of the first rectangular trajectory more accurate and the welding more uniform.

[0131] S110: According to the phase shift algorithm, adjust the first X-axis position trajectory, the first Y-axis position trajectory, and the first energy following curve to obtain a second X-axis position trajectory, a second Y-axis position trajectory, and a second energy following curve, and generate a second rectangular trajectory according to the second X-axis position trajectory, the second Y-axis position trajectory, and the second energy following curve.

[0132] In actual application, during the operation of the motor of the welding equipment, due to factors such as system response, it is very difficult to achieve synchronous control, which will cause a delay in the laser light output and affect the welding effect. Therefore, a phase shift algorithm is added for correction.

[0133] In some embodiments, as Figure 10 shown, the phase shift algorithm includes:

[0134] S1101: Process the preset offset time to respectively obtain the integer part and the decimal part of the offset time, and the calculation method is as follows:

[0135] int_ps_axis = floor(ps_axis)

[0136] Among them, floor() is the floor function, ps_axis is the offset time preset by the user, and int_ps_axis is the integer time after flooring.

[0137] float_time = (ps_axis - int_ps_axis)

[0138] Among them, float_time is the fractional part of the offset time, that is, float_time is the new offset time.

[0139] S1102: According to the integer part of the offset time, the fractional part of the offset time, and the first X-axis position trajectory / first Y-axis position trajectory / first energy following curve, calculate the second X-axis position trajectory / second Y-axis position trajectory / second energy following curve respectively. The motion controller of the laser welding equipment controls the movement of the axis motor and the output of laser energy according to the second X-axis position trajectory, the second Y-axis position trajectory, and the second energy following curve.

[0140] In some embodiments, the second X-axis position trajectory, the second Y-axis position trajectory, and the second energy following curve are calculated in the following manner:

[0141] endpos(i) = pos(int_ps_axis + i) + float_time * (pos(int_ps_axis + i + 1) - pos1(int_ps_axis + i))

[0142] Among them, endpos() is the new trajectory array calculated by interpolation, i is the array coordinate, pos() corresponds to the position of the first X-axis position trajectory or the first Y-axis position trajectory or the first energy following curve. The second X-axis position trajectory, the second Y-axis position trajectory, and the second energy following curve are obtained respectively in the above manner (wherein, the second X-axis position trajectory is calculated according to the first X-axis position trajectory, the second Y-axis position trajectory is calculated according to the first Y-axis position trajectory, and the second energy following curve is calculated according to the first energy following curve).

[0143] The present invention adopts a phase shift algorithm, which can modify the phases of the X-axis position trajectory, the Y-axis position trajectory, and the energy following curve, so that the control system of the entire welding equipment is synchronized, reducing the response time difference during the welding process, resulting in the laser being ahead or behind in light output, thereby improving the welding quality.

[0144] The method provided by the present invention applies the S-shaped curve planning algorithm and the uniform speed planning algorithm to the rectangular welding path planning and the energy following synchronous control. Compared with the methods such as the currently widely used position synchronous output (PSO), it has lower complexity and stronger flexibility. In the case of welding under different working conditions such as the acceleration section, deceleration section, uniform speed section, low speed section, and high speed section, it can adjust the energy following curve more flexibly and conveniently, making the overall welding uniform and consistent, and effectively improving the overall welding quality.

[0145] In another embodiment of the present invention, a motion controller of a laser welding device is provided, including: an X-axis motion controller, a Y-axis motion controller, and a laser controller; the X-axis motion controller is configured to receive the second X-axis position trajectory obtained by using the foregoing planning method to control the operation of the X-axis motor of the laser welding device; the Y-axis motion controller is configured to receive the second Y-axis position trajectory obtained by using the foregoing planning method to control the operation of the Y-axis motor of the laser welding device; the laser motion controller is configured to receive the second energy following curve information obtained by using the foregoing planning method to control the operation of the laser controller of the laser welding device.

[0146] The above uses specific examples to elaborate on the present invention, which is only used to help understand the present invention and is not intended to limit the present invention. For those skilled in the technical field to which the present invention pertains, based on the idea of the present invention, several simple deductions, deformations, or substitutions can also be made.

Claims

1. Planning method for rectangular laser welding trajectory and energy following, Characterized in that, Comprising: Obtaining a laser welding task set by a user, the laser welding task including dimension parameters and shape parameters, the shape parameters including a frame rectangle, a starting weld point arc and an ending weld point arc, and the four corners of the frame rectangle being rounded corners; Establishing a coordinate system according to the frame rectangle, the X-axis direction of the coordinate system being the direction where the long side of the frame rectangle is located, and the Y-axis direction of the coordinate system being the direction where the short side of the frame rectangle is located; Calculating, according to an S-curve planning algorithm and the dimension parameters, multiple sets of S-curve position values corresponding to the rectangular straight sides, the starting weld point arc and the ending weld point arc of the frame rectangle respectively, each set of S-curve position values corresponding to an S-curve, each set of S-curve position values including multiple S-curve position sub-values, and a single S-curve position sub-value corresponding to a single first trajectory point; Obtaining the first X-axis position, the first Y-axis position and the first combined axis displacement sub-value of each first trajectory point according to each S-curve position sub-value; Calculating, according to a uniform speed planning algorithm and a preset interpolation period, multiple sets of second combined axis displacement values corresponding to the rounded corners of the frame rectangle respectively, each set of second combined axis displacement values including multiple second combined axis displacement sub-values corresponding to second trajectory points; Obtaining the second X-axis position and the second Y-axis position of each second trajectory point according to each second combined axis displacement sub-value; Generating a first rectangular trajectory corresponding to the laser welding task according to the first X-axis positions and the first Y-axis positions of all the first trajectory points, and the second X-axis positions and the second Y-axis positions of all the second trajectory points, the first rectangular trajectory including a first X-axis position trajectory and a first Y-axis position trajectory; Obtaining a first energy value corresponding to each first trajectory point according to an energy following planning algorithm and each first combined axis displacement sub-value; Obtaining a second energy value corresponding to each second trajectory point according to an energy following planning algorithm and each second combined axis displacement sub-value; Performing laser energy following planning on the first rectangular trajectory according to all the first energy values and all the second energy values to generate a first energy following curve; Adjusting the first X-axis position trajectory, the first Y-axis position trajectory and the first energy following curve respectively according to a phase shift algorithm to obtain a second X-axis position trajectory, a second Y-axis position trajectory and a second energy following curve, and generating a second rectangular trajectory according to the second X-axis position trajectory, the second Y-axis position trajectory and the second energy following curve.

2. The planning method according to claim 1, Characterized in that, Further comprising: Performing connection speed planning on the connection points between the starting weld point arc and each rectangular straight side, the connection points between the ending weld point arc and the frame rectangle, and the connection points between each rounded corner of the frame rectangle and each rectangular straight side.

3. The planning method according to claim 2, Characterized in that, The method for planning the connection speed of the connection points between the starting weld arc and each rectangular straight edge, the connection points between the ending weld arc and the frame rectangle, and the connection points between each rounded corner of the frame rectangle and each rectangular straight edge includes: When the starting weld arc or the ending weld arc or the rounded corner of the frame rectangle connects to the rectangular straight edge, the connection speed of the connection point is the linear speed of the end point of the rounded corner of the frame rectangle, and the radii of the starting weld arc, the ending weld arc, and the rounded corner of the frame rectangle are equal; When the rectangular straight edge connects to the starting weld arc or the ending weld arc or the rounded corner of the frame rectangle, the connection speed of the connection point is the end point speed of the rectangular straight edge, and the end point speed of the rectangular straight edge is obtained according to the uniform motion planning algorithm.

4. The planning method according to claim 1, characterized in that the laser welding task further includes motion parameters, and the S-curve planning algorithm includes: According to the motion parameters, calculate the values of each time period corresponding to the S-curve. The time periods of the S-curve include the first uniform motion time period; According to the motion parameters, verify whether the value of the first uniform motion time period exists; If it exists, calculate the second uniform motion time period, and round up the interpolation time of each time period of the S-curve so that the interpolation time of each time period is an integer multiple of the preset interpolation period, where the interpolation time of each time period corresponds to each time period of the S-curve; If it does not exist, round up the interpolation time of each time period of the S-curve so that the interpolation time of each time period is an integer multiple of the preset interpolation period, and the interpolation time of each time period corresponds to each time period of the S-curve; According to the rounded-up interpolation time of each, calculate the displacement value of each time period; According to the displacement values of all time periods, generate a set of S-curve position values.

5. The planning method according to claim 1, characterized in that the uniform motion planning algorithm includes: According to the preset acceleration derivation method and angular velocity derivation method, calculate the angular velocity and linear velocity of each second trajectory point; According to the angular velocity, the linear velocity, the interpolation period, and the time point of each second trajectory point, calculate a corresponding set of second combined axis displacement values.

6. The planning method according to claim 1, characterized in that the method for obtaining the first X-axis position and the first Y-axis position of each first trajectory point according to each S-curve position sub-value includes: The first X-axis position of the first trajectory point corresponding to the long side of the frame rectangle is equal to the S-curve position sub-value of the first trajectory point, and its first Y-axis position is equal to zero; The first X-axis position of the first trajectory point corresponding to the short side of the frame rectangle is equal to zero, and its first Y-axis position is equal to the S-curve position sub-value of the first trajectory point.

7. The planning method according to claim 1, characterized in that the method for obtaining the second X-axis position and the second Y-axis position of each second trajectory point according to each second combined axis displacement sub-value includes: Calculate the angular velocity of each second trajectory point according to the second composite axis displacement sub-value of each second trajectory point; Calculate the second X-axis position and the second Y-axis position of each second trajectory point according to the angular velocity of each second trajectory point and a preset angle value.

8. The planning method according to claim 1, characterized in that, the parameters of the laser welding task further include energy parameters, and the energy following planning algorithm includes: Calculate the first composite axis speed interpolation point corresponding to each first trajectory point according to each of the first composite axis displacement sub-values; Calculate the second composite axis speed interpolation point corresponding to each second trajectory point according to each of the second composite axis displacement sub-values; Generate a first energy following curve according to the energy parameters, all the first composite axis speed interpolation points, all the second composite axis speed interpolation points, and the laser energy following model.

9. The planning method according to claim 1, characterized in that, the phase shift algorithm includes: Process the preset offset time to obtain the integer part and the decimal part of the offset time respectively; Calculate the second X-axis position trajectory / second Y-axis position trajectory / second energy following curve respectively according to the integer part of the offset time, the decimal part of the offset time, and the first X-axis position trajectory / the first Y-axis position trajectory / the first energy following curve.

10. A motion controller for a laser welding device, characterized in that, comprising: an X-axis motion controller, a Y-axis motion controller, and a laser controller; The X-axis motion controller is configured to receive the second X-axis position trajectory obtained by using the planning method according to any one of claims 1-9 to control the operation of the X-axis motor of the laser welding device; The Y-axis motion controller is configured to receive the second Y-axis position trajectory obtained by using the planning method according to any one of claims 1-9 to control the operation of the Y-axis motor of the laser welding device; The laser motion controller is configured to receive the second energy following curve information obtained by using the planning method according to any one of claims 1-9 to control the operation of the laser controller of the laser welding device.

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