JP2008290216A - Robot controller - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a robot controller in which an optimum pitch movement amount is automatically set according to the type of each of working tools. <P>SOLUTION: In this robot controller RC, the control points of the working tools 1A/1B/1C mounted on the wrist parts of robots 2A/2B/2C, respectively, are moved by predetermined pitch movement amounts by the manual operation of a teach pendant TP. The robot controller comprises an automatic pitch movement amount setting part 22 for automatically setting the pitch movement amount according to the type of each of the working tools 1A/1B/1C. When a working tool information storage part 23 is referred to and the present working tool is determined to be a consumable electrode arc welding torch, the pitch movement amount is calculated by multiplying a welding wire diameter value pre-set in a wire diameter storage part 24 by the ratio stored in a ratio storage part 25, and automatically set. Consequently, a teaching operation time can be reduced and an operability can be improved. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a robot control apparatus that moves a control point of a work tool by a predetermined minute amount.

  Conventionally, teaching is performed while finely adjusting a target position with respect to a workpiece by moving a control point of a work tool attached to a wrist portion of an industrial robot by a predetermined fine amount. In general, an operation for fine adjustment is referred to as a pitch operation, and a fine amount is referred to as a pitch movement amount (see, for example, Patent Document 1).

  Hereinafter, the prior art will be described by taking an arc welding robot with a consumable electrode type arc welding torch as a work tool as an example.

  FIG. 3 is a block diagram of a conventional arc welding robot. In the figure, the arc welding robot 2 is connected to a robot controller RC. A consumable electrode type arc welding torch 1 (hereinafter simply referred to as a welding torch 1) is attached to the wrist of the arc welding robot 2 as a work tool. A welding wire 5 as a filler material is inserted into the welding torch 1 and protrudes from the welding torch 1 by a predetermined length.

  The control point C is a position that is an object of operation control, also called TCP (Tool Center Point). In the case of the arc welding robot 2, the control point C corresponds to the distal end portion of the welding wire 5 protruding from the welding torch 1. To do.

  The robot controller RC includes a CPU 11 serving as a control center, a RAM 12 serving as a temporary storage area, a ROM 13 storing each control software, a hard disk 14 serving as a nonvolatile storage area, and drive control for driving the arc welding robot 2. Part 9 is provided. The teach pendant TP, which is a portable operation unit, is connected to the robot controller RC, and manually operates the arc welding robot 2, and various control constants such as work tool information, wire diameter, and pitch movement amount, which will be described later. Can be set.

  The ROM 13 includes an operation control unit 21 that outputs a signal for controlling the operation of the arc welding robot 2 to the drive control unit 9. The hard disk 14 includes a work tool information storage unit 23, a wire diameter storage unit 24, and a pitch movement amount storage unit 26.

  The work tool information storage unit 23 stores control constants necessary for operation control such as the type of work tool and tool parameters that define the shape of the tool. The wire diameter storage unit 24 stores a diameter value of the welding wire (hereinafter referred to as a wire diameter) as one of control constants necessary for arc welding. The pitch movement amount storage unit 26 stores a pitch movement amount. An appropriate fine amount (for example, 0.5 mm or the like) is set in advance as the initial value of the pitch movement amount, but it is also possible for the operator to change it to a desired value.

  Next, the operation will be described. When a pitch operation signal Ps is input to the robot controller RC by selecting a mode in which the operator performs a pitch operation with the teach pendant TP and performing a predetermined key operation, the control point C of the arc welding robot 2 is set. It moves by the pitch movement amount and stops.

  As described above, the operator can set a desired value for the pitch movement amount. As the desired value, in the case of the arc welding robot described above, a value obtained by halving the wire diameter is often used. For example, if the wire diameter of the welding wire currently in use is 1.6 mm, 0.8 mm is set as the pitch movement amount. Hereinafter, the reason why ½ times the wire diameter is used as a guide will be described.

  FIG. 4 is a diagram for explaining how the target position is finely adjusted. In the figure, a target position K is a position where the operator wants to teach by moving the tip (control point C) of the welding wire 5. However, as shown in FIG. 6A, when it is difficult to move the control point C of the welding wire 5 so that it completely coincides with the target position K due to restrictions on the control performance of the robot. There are many. For this reason, as shown in FIG. 5B, the operator teaches the target position K in a range that does not affect the welding quality, that is, in a range that has a target margin corresponding to the radius of the welding wire 5. Yes. That is, a value obtained by halving the wire diameter is set as the pitch movement amount, and the teaching operation is performed by repeating the pitch operation.

In the above, the guideline of the pitch movement amount when the arc welding torch is a consumable electrode type has been described. Similarly, when the arc welding torch is a nonconsumable electrode type, the pitch movement amount is set with reference to 1/2 of the tip diameter of the tungsten electrode. is doing. In the case of a spot welding robot with a spot welding gun attached as a work tool, the pitch movement amount is set with reference to 1/2 the tip diameter of the electrode tip. In the case of a robot equipped with a grinder, a polishing machine, a gripping hand, etc. as work tools, the pitch movement amount is set according to the shape and characteristics of each work tool.
JP 2001-269883 A

  As described above, the operator presets the desired value of the pitch movement amount according to the wire diameter of the welding wire in use, the shape of the work tool, etc., but conversely speaking, the work tool currently in use Therefore, there is a problem that it is necessary for the operator to manually set an optimal pitch movement amount according to the above. For example, in the case of the above-described consumable electrode type arc welding robot, there are various diameters of welding wires, so the work is to set the desired value after confirming the wire diameter currently in use before using the robot. Had the problem of being necessary.

  Even if a means for setting the pitch movement amount is provided, the operability remains inferior without changing the pitch movement amount from the initial value to the desired value due to lack of manuals, lack of education for workers, etc. It was sometimes used. As a result, there is a problem that the teaching of the target position is out of the range of the target tolerance and adversely affects the welding quality.

  Furthermore, in current industrial robots, a single robot connected to a single robot controller can be used by switching a plurality of work tools by a work tool exchange function called a tool changer, or using different work tools. It is common to simultaneously control a plurality of robots equipped with In such a robot, the pitch movement amount cannot be set for each work tool or for each robot. For example, when a plurality of welding torches having different wire diameters are used by one arc welding robot, teaching is performed. In this case, it is necessary to set the pitch movement amount according to the welding torch being selected. Further, even when an arc welding robot, a spot welding robot, a handling robot, or the like is connected to one robot control device and controlled, it is necessary to set the pitch movement amount according to the work tool at each teaching.

  Accordingly, an object of the present invention is to provide a robot control device that can reduce the teaching work time by automatically setting an optimal pitch movement amount according to the type of work tool.

  To achieve the above object, according to a first aspect of the present invention, there is provided a robot control apparatus for manually moving a control point of a work tool attached to a wrist portion of a robot by a predetermined pitch movement amount according to a type of the work tool. And a pitch movement amount automatic setting unit for automatically setting the pitch movement amount.

  According to a second aspect of the present invention, when the work tool is a consumable electrode arc welding torch, the pitch movement amount automatic setting unit multiplies the predetermined welding wire diameter value by a predetermined ratio to calculate the pitch movement amount. The robot control device according to the first aspect of the invention is characterized in that it is calculated and set.

  A third invention is the robot control apparatus according to the second invention, wherein the ratio is 1/2.

  According to a fourth aspect of the present invention, there is provided the robot control apparatus according to the second aspect, further comprising a ratio setting unit for arbitrarily designating the ratio.

  According to the first invention, the pitch movement amount corresponding to the type of work tool is automatically set. For example, when a plurality of robots such as arc welding robots and spot welding robots are connected, when the work tool is switched by one robot, the operator manually operates according to the work tool currently in use. Since there is no need to set the amount of pitch movement for each operation, the number of work steps can be reduced.

  According to the second invention, when the work tool is a consumable electrode type arc welding torch, the pitch movement amount is automatically set based on a preset wire diameter. That is, since the optimum pitch movement amount for consumable electrode arc welding based on the wire diameter is automatically set, teaching of the target position can be easily performed in addition to the effect of the first invention. . Further, since the wire diameter is a control constant that is essential for consumable electrode arc welding and should be determined in advance, an optimum value based on the wire diameter is automatically set without the operator being aware of the pitch movement amount. Furthermore, the operability is improved and the target position can be always taught within the target tolerance range, so that the welding quality can be improved.

  According to the third aspect, since the ratio with respect to the wire diameter is halved, in addition to the effects exhibited by the first and second aspects, the target position can be taught more easily.

  According to the fourth invention, since the ratio setting unit for arbitrarily specifying the ratio with respect to the wire diameter is provided, in addition to the effects exhibited by the first and second inventions, more optimal according to the target margin A simple pitch movement amount can be set.

  DESCRIPTION OF EMBODIMENTS Hereinafter, embodiments of the invention will be described based on examples with reference to the drawings.

  FIG. 1 is a block diagram of the industrial robot of the present invention. In the figure, the same components as those in the prior art shown in FIG.

  The arc welding robot 2A, the arc welding robot 2B, and the spot welding robot 2C are connected to the robot controller RC. A welding torch or spot welding gun as a work tool is attached to the wrist of each robot. That is, a welding torch 1A is attached to the arc welding robot 2A, a welding torch 1B is attached to the arc welding robot 2B, and a spot welding gun 1C is attached to the spot welding robot 2C. The welding torches 1A and 1B are inserted with welding wires 5A and 5B as fillers, respectively, and protrude from the welding torches 1A and 1B by a predetermined length.

  The control points Ca to Cc of each work tool are the positions subject to operation control, also called TCP (tool center point), the control point Ca is at the tip of the welding wire 5A, and the control point Cb is the welding wire 5B. The control point Cc corresponds to the pressure point by the electrode tip.

  The robot controller RC includes a CPU 11, a RAM 12, and drive control units 9A to 9C for driving the robots 2A to 2C, respectively. The teach pendant TP is used to select one of the robots 2A to 2C and perform manual operation, or to perform various settings such as work tool information and a wire diameter to be described later.

  The ROM 13 includes an operation control unit 21 and a pitch movement amount automatic setting unit 22. The operation control unit 21 outputs a signal for controlling the operation of each robot to the drive control units 9A to 9C, identifies the currently selected work tool, and requires necessary control constants from the work tool information storage unit 23 described later. Is read and set. The pitch movement amount automatic setting unit 22 automatically calculates and sets the pitch movement amount according to the type of the currently selected work tool. The pitch movement amount automatic setting unit 22 will be described later.

  The hard disk 14 includes a work tool information storage unit 23, a wire diameter storage unit 24, a ratio storage unit 25, and a pitch movement amount storage unit 26.

  The work tool information storage unit 23 stores, for each work tool, control constants necessary for operation control, such as a work tool type and a tool parameter that defines the shape of the tool. In the figure, since there are three work tools, three pieces of work tool information are stored. In the work tool information, in addition to the control constant, a desired value of the pitch movement amount may be set and stored. Hereinafter, the desired value of the pitch movement amount is not stored in the work tool information of the welding torch 1A and the welding torch 1B, and the desired value of the pitch movement amount is stored in the work tool information of the spot welding gun 1C. It will be explained as a thing.

  The wire diameter storage unit 24 stores a wire diameter as one of control constants necessary for arc welding. The wire diameter may be stored in association with the above-described work tool information, or may be stored in the work tool information storage unit 23 as one of the work tool information. The ratio storage unit 25 stores a ratio with respect to the wire diameter used for calculating the pitch movement amount. This ratio is preferably ½, but by providing a ratio setting unit, it may be configured such that an operator can specify an arbitrary ratio from the teach pendant TP. The pitch movement amount storage unit 26 stores the pitch movement amount calculated by the pitch movement amount automatic setting unit 22.

  Next, an operation in which the pitch movement amount is automatically set according to the type of work tool will be described.

  FIG. 2 is a flowchart showing a processing flow of the pitch movement amount automatic setting unit 22. In step S1 in the figure, the work tool information of the work tool attached to the currently selected robot is read. Next, in step S2, it is determined based on the work tool information whether the current work tool is a consumable electrode arc welding torch. If it is determined that it is a consumable electrode arc welding torch, the process proceeds to step S3. If it is determined that it is not a consumable electrode arc welding torch, the process proceeds to step S5.

  In step S3, the wire diameter and ratio are read. In step S4, the pitch movement amount is calculated by multiplying the wire diameter by the ratio.

  In step S5, if it is a consumable electrode arc welding torch, the pitch movement amount calculated in step S4 is used. If it is not a consumable electrode arc welding torch, the pitch movement amount stored in the work tool information read in step S1 is This is stored in the movement amount storage unit 26.

  Through the above steps, the pitch movement amount corresponding to the currently selected work tool is automatically set. When the pitch operation signal Ps is input from the teach pendant TP by the operator's operation, the control point of the selected robot is moved by the set pitch movement amount and stopped.

  As described above, the pitch movement amount corresponding to the type of work tool is automatically set. For example, when a plurality of robots such as arc welding robots and spot welding robots are connected, when the work tool is switched by one robot, the operator manually operates according to the work tool currently in use. Since there is no need to set the amount of pitch movement for each operation, the number of work steps can be reduced.

  In particular, when the work tool is a consumable electrode arc welding torch, the pitch movement amount is calculated based on a preset wire diameter. That is, since the optimum pitch movement amount for consumable electrode arc welding based on the wire diameter is automatically set, in addition to the above effects, the target position can be easily taught. Further, since the wire diameter is a control constant that is essential for consumable electrode arc welding and should be determined in advance, an optimum value based on the wire diameter is automatically set without the operator being aware of the pitch movement amount. Furthermore, the operability is improved and the target position can be always taught within the target tolerance range, so that the welding quality can be improved.

  Moreover, since the ratio with respect to the wire diameter is set to ½, in addition to the above effects, the target position can be taught more easily.

  Further, since the ratio setting unit for arbitrarily specifying the ratio with respect to the wire diameter is provided, in addition to the above effects, an optimum pitch movement amount that matches the target margin can be set.

  In the embodiment described above, an example is shown in which two arc welding robots and one spot welding robot are connected to one robot control device, but the present invention is not limited to this embodiment. Even when a plurality of welding torches are switched and used by a tool changer mechanism with one arc welding robot, the pitch movement amount can be automatically calculated and set in the same manner as described above.

It is a block diagram of the industrial robot of this invention. It is a flowchart which shows the flow of a process of the pitch movement amount automatic setting part of this invention. It is a block diagram of the conventional arc welding robot. It is a figure for demonstrating a mode that a target position is finely adjusted.

Explanation of symbols

1 welding torch 1A welding torch 1B welding torch 1C spot welding gun 2 arc welding robot 2A arc welding robot 2B arc welding robot 2C spot welding robot 5 welding wire 5A welding wire 5B welding wire 9 drive control unit 9A drive control unit 9B drive control unit 9C Drive control unit 14 Hard disk 21 Operation control unit 22 Pitch movement amount automatic setting unit 23 Work tool information storage unit 24 Wire diameter storage unit 25 Ratio storage unit 26 Pitch movement amount storage unit
K target position Ca control point Cb control point Cc control point Ps pitch operation signal RC robot controller TP teach pendant

Claims (4)

In the robot control device that moves the control point of the work tool attached to the wrist portion of the robot by a predetermined pitch movement amount by manual operation,
A robot control apparatus comprising a pitch movement amount automatic setting unit that automatically sets the pitch movement amount according to a type of the work tool.   When the work tool is a consumable electrode arc welding torch, the pitch movement amount automatic setting unit calculates and sets the pitch movement amount by multiplying a preset welding wire diameter value by a predetermined ratio. The robot control apparatus according to claim 1, wherein   The robot control apparatus according to claim 2, wherein the ratio is ½.   The robot control apparatus according to claim 2, further comprising a ratio setting unit for arbitrarily specifying the ratio.

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