KR100415820B1 - Controlling method for weaving motion of welding robot - Google Patents

Abstract

The present invention relates to a method of controlling the weaving motion of a welding robot for realizing a weaving motion close to the welding performed by a welder during welding. The present invention teaches a target position, sets a welding parameter, and a welding path based on a target position taught by a parameter. By calculating and performing the weaving welding according to the calculated path, it is possible to calculate all the welding paths at one time only by teaching and setting parameters of the target position without a separate device, thereby performing a smooth weaving operation.

Description

Controlling method for weaving motion of welding robot

The present invention relates to a method for controlling a welding robot, and more particularly, to a method for controlling a weaving motion of a welding robot for realizing a weaving motion close to welding performed by a welder during welding.

Recently, various types of industrial robots have been used in industrial fields, and among them, welding robots for welding various materials such as steel sheets have also been proposed. In welding using a robot, the base material to be welded is transported and fixed to a jig, and when the welding start point and the welding end point on the welding line to be welded are input to the target base material, the controller drives the welding torch based on the stored predetermined program. Weld.

In order to weld such a base material, a method such as arc welding is mainly used. Arc welding is a welding method in which a strong current is formed between a welding torch and a welding base material while supplying a wire to the welding torch to melt and fuse the wire and the base material instantaneously. When arc welding is carried out, predetermined welding conditions are set in advance according to the type of the base material and the shape of the mutual contact of the welding site to be welded. These welding conditions include a welding current, a welding voltage, the separation distance between the welding torch and the base material, the feeding speed of the wire and the speed of the weaving motion by the welding torch.

Weaving motion means that the robot performs oscillation motion by moving back and forth instead of just a straight line / curve to increase the amount of penetration in a single path movement when the robot performs welding. .

Conventional weaving motion is composed of N weaving cycles between the welding start point (# PNT1) and the welding end point (# PNT2), each of the weaving cycle is composed of four unit lines (# 1/4 to # 4/4). That is, the weaving motion is performed by a combination of # 1/4 per 1 to # 4/4 per N straight lines.

Hereinafter, the above-described conventional weaving motion operation will be described.

When the weaving motion command falls on the robot language program (S10), the position of the current robot is checked (S20). N weaving cycles for the weaving motion from the start point # PNT1 to the end point # PNT2 are generated and a position for this is calculated (S30).

The path of the unit line (# n / 4) of the current position and the weaving cycle to proceed is calculated (S40). That is, when the weaving motion starts, the path of the first unit line # 1/4 per 1 is calculated from the starting point # PNT1.

When the robot starts the weaving motion with respect to the calculated path by controlling each driving unit (S50), the robot moves along # 1/4 per 1 in the calculated path # PNT1 and performs welding. When welding is completed along the calculated path, the weaving motion of the corresponding path is stopped (S60).

Then, it is determined whether the current position is the end of the weaving motion. That is, it is determined whether the current position is the end point # PNT2 (that is, the position terminated to # 4/4 per N) (S70). If it is determined in step S70 that it is not the end point, the path of the current position # 1/4 per 1 and the position # 2/4 per 1 to continue is calculated (S40).

If it is determined in step S70 that the current position is the end point # PNT2, the weaving motion is terminated (S80).

The conventional weaving motion described above does not perform weaving-specific path planning for the entire weaving path area, that is, a weaving cycle that combines unit motion without the path planning for pure weaving motion. This is how we implemented it. This weaving motion is made by combining tens to hundreds of unit straight lines in one cycle, that is, combining short paths one by one. In other words, since every linear path is calculated and operated individually instead of at once, the weaving motion itself lacks the continuity of the operation, resulting in unnatural welding results.

The present invention is to solve the above problems, an object of the present invention is to provide a weaving motion control method of the welding robot that can implement a smooth weaving operation.

1 is a flow chart for explaining a weaving motion control method of a conventional welding robot.

Figure 2 is a block diagram for explaining a welding robot according to the present invention.

3 is an explanatory diagram for explaining a weaving motion according to the present invention;

Figure 4a, 4b is an explanatory diagram for explaining the weaving motion of the welding robot according to the present invention.

5a and 5b are explanatory views for explaining the weaving motion of the welding robot according to the present invention.

Figure 6 is a flow chart for explaining a weaving motion control method of a usage robot according to the present invention.

Explanation of symbols on the main parts of the drawings

10: control means 11: first storage unit

12: second storage unit 20: input unit

30: display part 40: central processing part

50: axis controller 60: servo circuit

70: welder interface 80: robot mechanism

90: arc welding controller 100: welding torch

Weaving motion control method of the welding robot according to the present invention in order to achieve the above object, the step of teaching the target position, the step of setting the welding parameters, calculating the welding path by the parameters and the taught target position, calculation And performing the weaving welding along the route.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings.

Referring to FIG. 2, the robot mechanism 80 of the welding robot according to the present invention described above includes a welding torch 100 at a joint portion, and the welding torch 100 is an arc welding power controller 90. The robotic mechanism 80 and the arc welding power controller 90 are connected to the control means 10 to be controlled.

The control means 10 includes a central processing unit (CPU) 40, storage units 11 and 12, an input unit 20, a display unit 30, and an axis controller 50. And a welder interface 70, all of which are connected to the central processing unit 40 via a bus. The control means also includes a servo circuit portion 60 for controlling a servo motor (not shown) or the like for driving respective axes of the robotic mechanism 80.

The storage unit comprises a first storage unit 11 for storing a control program and a second storage unit 12 for storing data and control parameters. The input unit 20 includes various input buttons (not shown) for operating the welding robot and inputting data, and the display unit 30 includes a display such as a CRT or LCD to display the operating state of the welding robot. . The axis controller 50 includes an interpolator (not shown) for controlling a plurality of axes. In addition, a plurality of sensors (encoders; not shown) are installed in each part of the welding mechanism, and the data detected through the sensors is stored in the second storage unit 12 through the central processing unit 40.

The general process of arc welding is as follows.

The predetermined target base material is fixed to the welding jig. The central processing unit 40 performs welding according to the pre-stored data. Before the welding, the central processing unit 40 checks the welding start line, the welding end point, and the welding line of the welding site, which compensates the error based on the actual position of the base material to be welded. The method of calculating and confirming the welding line of the welding start point, the welding end point and the welding portion is already known. For example, the contact shape type between the base materials centered on the welding line, the rough welding start point and the end point of the welding line are set, the welding torch is positioned at a part of the space adjacent to the welding start point, and the welding torch is directed toward the base material. By detecting the contact between the welding torch and the base material by moving the position of the base material, there is a method of welding by calculating the welding line based on the contact shape type and the determined position of the base material between the base materials.

On the other hand, when the welding torch of the welding robot is disposed at the starting point of welding, the gas supply device supplies the shielding gas, while welding the target base material while properly supplying the wire through the wire supply device.

Hereinafter, the weaving motion according to the present invention will be described.

Referring to FIG. 3, when the base materials 111 and 112 are welded, the weaving motion according to the present invention has three coordinate axes consisting of x, y, and z. The x axis is a left and right weaving motion direction, and the y axis is a welding progress direction ( Linear motion path direction), and the z axis is the weaving perpendicular direction (torch approach direction).

The weaving motion is optional (/ opt), weaving type (TYPE), weaving frequency (FREQ), weaving amplitude (AMP), left and right delay time (TIME LEFT, TIME RIGHT) or left and right travel distance (DL, DR), And many other parameters. Each parameter value is input from a user through an input unit or uses preset data stored in the storage unit 10.

The option (/ opt) designates an end point of the weaving motion. For example, when welding a thin plate and a thick plate, the welding is terminated at the plate to prevent damage to the plate. When the thick plate is located on the left side of the welding progress direction, the webbing ends on the left side 122 of the weaving reference line on the weaving plane 121 with the option (/ opt) as / L (see FIG. 4A), and the thick plate is welded. If it is located on the right side of the direction, the option (/ opt) is set to / R to end the weaving at the right side 9223 of the weaving reference line on the weaving plane 121 (FIG. 4B). If there is no option (/ opt), weaving ends at the weaving baseline.

The weaving type (TYPE) defines a weaving type. The weaving type (TYPE) is divided into single vibration weaving if the types 1 and 2, pendulum-type weaving if 3, and user weaving if 0. The single vibration weaving is a base material is stationary and the welding is performed while the welding torch moves by the motion of the welding robot. When the weaving type (TYPE) is 1, it has a cogwheel-shaped weaving shape as shown in FIG. TYPE) is 2, and has a trapezoidal weaving shape as shown in FIG. 5B. The pendulum-type weaving is the base material is conveyed and the welding torch is welded while the pendulum movement in the vertical direction with respect to the conveying direction of the base material.

The weaving frequency (FREQ) is for designating the number of weaving when the weaving motion is performed, and has a range of 0.1 to 9.9 kHz. That is, when the weaving frequency FREQ is 1 kHz, weaving is performed once per second.

The weaving amplitude (AMP) is to determine the vibration range from the weaving reference line connecting the starting position (# PNT1) and the target position (# PNT2) in the weaving motion according to the weaving frequency from left to right, from 0.1 to left and right It has a range of 99 mm.

The left delay time (TIME LEFT) is a parameter applied to pendulum-type weaving or cogwheel-type single vibration weaving. The time to stay at the highest point when moved is in the range of 0.1 to 9.9 sec. In addition, the right delay time (TIME RIGHT) is also a parameter applied to the gear type single vibration weaving, when the single vibration weaving is performed according to the weaving frequency (FREQ), the highest point when the right side moves by the weaving amplitude (AMP) from the weaving reference line. Dwell time in the range of 0.1 to 9.9 sec (FIG. 5A).

The left traveling distance DL is a parameter applied in trapezoidal single vibration weaving, and when the single vibration weaving is performed according to the weaving frequency FREQ, the left traveling distance DL moves to the left by the weaving amplitude AMP from the weaving reference line, and then moves in the welding progress direction. Distance, in millimeters (mm). In addition, the right traveling distance DR is also a parameter applied to trapezoidal single vibration weaving. When the single vibration weaving is performed according to the weaving frequency FREQ, the right traveling distance DR moves to the right by the weaving amplitude AMP from the weaving reference line and then moves in the welding progress direction. 5b). In the weaving motion control method according to the present invention, when the weaving motion is in progress, the following interrupt signal (I / O no. Or @ R ##) is received from the outside. , **) occurs, immediately end the weaving motion. In the weaving motion control method according to the present invention, in the case of pendulum-type weaving (in-place weaving) designated as TYPE2, I / O / no. Is added to the parameter of the single vibration weaving to end the weaving motion. That is, when the I / O no. Is set to 1, if the value of the input terminal of the central processing unit 40 is -1, the weaving motion is continued. On the contrary, if the value of the input terminal is 1, the weaving motion is terminated. Also, when "external variable, number" is added to the parameter in pendulum-type weaving, the weaving operation is terminated if the value of external variable @ R ## matches "**" which follows. This method can be applied to the case of controlling several welding robots using one central processing unit 940.

The welding speed is a speed when the welding torch moves from the starting position # PNT1 to the target position # PNT2, and has a range of 8 to 16 mm / sec.

The weaving control method of the welding robot according to the present invention, when teaching the target point (# PNT2) with the current position and the starting point (# PNT1), the weaving motion by the point and the parameters taught Is done. The teaching means that the user inputs the coordinates of the starting point # PNT1 and the destination point # PNT2 through the input unit 920 so that the central processing unit 40 can recognize it. That is, the central processing unit 940 recognizes coordinate values input through the input unit 20, and determines the start position and the end position of the weaving motion with reference to the coordinate values.

Hereinafter, the application form and application examples of the above-described parameters will be described.

Each parameter is applied in the format of WS (/ opt) TYPE, FREQ, AMP, TIME LEFT (or DL), TIME RIGHT (or DR), (I / O no. Or @ R ##, **). Is the weaving motion start command.

1) Gear type single vibration weaving

WS 1, 1.5, 4, 0, 0

WS is a weaving motion start command that initiates single vibration weaving with frequency 4 and amplitude 1.5 times per second with weaving type 1. At this time, since the weaving type (TYPE) is the first, the welding torch 100 performs the single vibration weaving of the gear type, and the left and right delay times (TIME LEFT and TIME RIGHT) are zero.

2) Trapezoidal Type Single Vibration Weaving

WS 2, 1.5, 4, 2, 1

WS is a weaving motion start command with weaving type 2, i.e. trapezoidal pendulum weaving. Welding is to be 1.

3) Pendulum Weaving

WS 3,1.5,4,0,0

WS is a weaving motion start command that starts pendulum-type weaving with frequency 4 and amplitude 1.5 times per second with weaving type 3.

Hereinafter, the weaving control method of the welding robot according to the present invention will be described with reference to FIG. 6.

The central processing unit 40 performs welding by controlling a welding robot and an arc welding machine according to a program stored in the first storage unit 11. In the case of the weaving motion, the central processing unit 40 follows the following procedure.

The central processing unit 40 detects the position # PNT0 of the current welding torch 100 (S100). At this time, the position (# PNT0) of the current welding torch 100 is detected by the signal fed back from the robot mechanism 80 during the operation of the welding robot, the method is in accordance with the conventional robot position detection method.

After detecting the current position # PNT0, the user teaches the target position # PNT2 via the input unit 20 (S110). And the user inputs parameters such as welding speed, weaving type (TYPE), weaving frequency (FREQ), weaving amplitude (AMP), left and right delay time (TIME LEFT, TIME RIGHT) to the input unit 20 or stored in the storage unit A preset parameter value is set (S120). At this time, when the weaving type (TYPE) is trapezoidal weaving of the single vibration type weaving, the left and right delay times (TIME LEFT, TIME RIGHT) are left and right travel distances (DL, DR).

When the setting of the parameter is completed, the central processing unit 40 calculates all paths between the start position # PNT1 and the target position # PNT2 (S130). After the path is calculated, the central processing unit 40 stores the data about the calculated path in the second storage unit 12.

When all the paths are calculated, the central processing unit 40 performs welding while weaving the welding torch 100 according to the parameter value while moving the welding torch 100 along the calculated path by controlling the welding robot (S140). Accordingly, the welding torch 100 moves at a set speed from the start position # PNT1 to the target position # PNT2, and oscillates by the weaving amplitude AMP according to the weaving frequency FREQ. .

As described in detail above, according to the weaving motion control method of the welding robot according to the present invention, it is possible to calculate all the welding paths at one time only by teaching and setting parameters of the target position without a separate device and perform a smooth weaving operation accordingly. have.

Claims (9)

In the control method of the welding robot which performs welding to the welding part between the base materials which mutually contact, Teaching the destination location, Setting a welding parameter including a weaving type, a weaving frequency, and a weaving amplitude on a straight path between the welding start position and the target position; Calculating a welding path by the welding parameter and the taught target position; Weaving control method of the welding robot, characterized in that it comprises the step of performing the weaving welding in accordance with the calculated welding path. delete The method of claim 1, The weaving type, A pendulum-type weaving in which a welding torch vibrates from side to side on the straight path and the base material moves; The base material is fixed and the welding robot weaving control method of the welding robot, characterized in that it comprises a single vibration type weaving vibrating on the linear path to the target position. The method of claim 1, The weaving amplitude is a weaving control method of the welding robot, characterized in that the amplitude of the welding torch to move to the left and right of the straight path. The method of claim 1, The weaving frequency is a weaving control method of the welding robot, characterized in that the number of times the execution of the welding torch vibrates to the left and right of the straight path. The method of claim 3, wherein When the pendulum-type weaving the parameter A left delay time for setting the time of staying at the left highest point of the weaving amplitude based on the straight path; Weaving control method of the welding robot, characterized in that further comprising a right delay time for setting the time to stay at the right highest point of the weaving amplitude on the basis of the straight path. The method of claim 3, wherein The single vibration type weaving is a gear type weaving, The parameter is a left delay time for setting the time to stay at the left highest point of the weaving amplitude on the basis of the linear path, Weaving control method of the welding robot, characterized in that further comprising a right delay time for setting the time to stay at the right highest point of the weaving amplitude on the basis of the straight path. The method of claim 3, wherein The single vibration type weaving is trapezoidal weaving, The parameter is a left travel distance for setting the travel distance from the left highest point of the weaving amplitude on the basis of the straight path, Weaving control method of the welding robot, characterized in that it further comprises a right traveling distance to set the travel distance at the right highest point of the weaving amplitude on the basis of the straight path. The method of claim 1, The parameter further comprises a weaving end point for setting the end of the weaving motion at any one of the left and right of the target position on the basis of the straight path.