JP2012228736A - Method and system for preparing offline teaching data - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an offline teaching data preparing method and an offline teaching data preparing system, in which a dangerous situation such as a possibility of occurrence of interference can be sensuously comprehend and information is provided for an operator to easily avoid the dangerous situation in teaching operation.SOLUTION: The offline teaching data preparing system includes: a teaching data preparing device 5 for preparing the teaching data to the welding robot 2 by using three dimensional data involving a workpiece W and a welding robot 2 and calculating virtual reaction force inversely proportional to a distance between the welding robot 2 and the workpiece W; and an input/output device 7 that can input movement and rotation of a control point of the welding robot 2 in the three dimensional data and of outputting the virtual reaction force calculated by the teaching data preparing device 5. By using the offline teaching data preparing system, the teaching data preparing device 5 executes a reaction force calculating step of calculating the total force of the virtual reaction force, and a reaction force outputting step of outputting magnitude and a direction of the calculated total force of the virtual reaction force to the input/output device 7 to prepare the teaching data for the robot.

Description

  The present invention provides a method for creating offline teaching data for a robot, which displays on a display screen three-dimensional graphic data of a workpiece stored in a teaching data creation apparatus constituted by a computer or the like, and teaches an operation locus of the robot with respect to the workpiece. And an off-line teaching data creation system.

Conventionally, in the field of robot welding and the like, as shown in Patent Document 1, teaching of a robot has been performed by a robot operation device (master arm) arranged at the operator's hand.
However, in recent years, an operation of teaching a desired operation to a robot has been performed by generating an operation trajectory of the robot by using a teaching data generation apparatus configured by a computer or the like instead of an operation device of the robot. This off-line teaching work displays the three-dimensional graphic data of a work on a display screen, and creates a robot motion trajectory while designating the work position and posture of the robot with respect to the graphic data constituting the work. Is.

As such a technique, there is one disclosed in Patent Document 2.
The robot operation teaching system of Patent Document 2 includes a manipulator having a plurality of joints and a grip, and a direct drive motor for each joint and an encoder that outputs a movement amount detection signal of a joint angle for each joint; The position / posture of the teaching target robot is determined by processing a three-dimensional solid shape process for modeling the teaching target robot and the robot working environment and the movement amount detection signal that changes according to the operation of the gripping unit. Predicting the magnitude and direction of the reaction force applied to the teaching target robot and the torque value applied to each joint when a collision with another object occurs, and causing the direct drive motor to generate a torque corresponding to the torque value A calculation control device for outputting a control signal, creating display output data and storing teaching data; and It is characterized in that the Tsu bets and 3-dimensional position and orientation of the robot working environment on the screen includes a display device and for continuously displaying.

According to this robot motion teaching system, in creating teaching data, it is possible to perform a collision check in the taught motion path in real time, and to display the robot and work environment at the time of the collision on the display device. ing.
The robot operation teaching technique described above has not only a two-dimensional mouse (ordinary mouse used for computer operation) but also a three-dimensional or more input means for moving the robot teaching point in specifying the robot work position and posture. It seems that operability can be improved by using an input device.

As input devices focused on improving operability, devices disclosed in Patent Literature 3 and Patent Literature 4 have been developed.
In Patent Document 3, in addition to a hand / arm operation input device for master / slave control based on a hand / arm operation of an operator that can supply a command signal by switching an operation target, a command for designating strength by an operation of one foot There is disclosed a robot control device that includes a foot operation input device that outputs a signal on a floor surface, and further includes a switching operation input device that generates an operation command on / off signal.

  In Patent Document 4, the input / output device main body reliably transmits propulsive force in the circumferential direction on the ground surface, and moves in all directions using near-zero friction wheels in which the force is not transmitted in the vertical direction, that is, the rotation axis direction. A mechanism is disclosed, and a wheel of the omnidirectional movement mechanism is composed of a plurality of omni foils having barrel type rollers arranged on the outer periphery.

JP-A-8-90461 JP 62-28281 A JP 2005-66752 A Japanese Patent Application No. 2000-357048

By the way, in creating the offline teaching data, the robot arm and the tool attached to the tip of the robot are made to enter the contact work area while avoiding contact with the work and the surrounding environment, and while avoiding the contact. It is necessary to teach a trajectory for retreating from the contact work area.
Therefore, the off-line teaching disclosed in Patent Document 2 is provided with an interference check function for checking whether or not interference (collision) has occurred between the arm or tool model and the workpiece or ambient environment model.

  However, this interference check function checks the fact that the arm or tool model actually interfered with the workpiece or the surrounding environment model. Therefore, the operator can know the location of interference only when the arm or tool model interferes with the workpiece or the surrounding environment model. Therefore, the technique disclosed in Patent Document 2 is not configured to grasp the danger of interference in advance and actively avoid interference, and for an operator who is teaching, an arm or tool It is very difficult to grasp the interval between the model and the model of the workpiece and the surrounding environment.

Note that even if the input device focused on improving the operability disclosed in Patent Document 3 and Patent Document 4 is used, it cannot contribute to the improvement of workability such as creating teaching data while avoiding interference in advance. It seems to be.
Although not listed in the patent literature, there is also a method of automatically calculating a trajectory that avoids interference in order to reduce the burden on the operator. However, there are many problems that not only a long calculation time is required but also a rational trajectory in consideration of the operation after entering / retreating cannot be obtained.

  In view of the above-mentioned problems, the present invention provides information to the operator so that a dangerous situation in which interference may occur can be sensibly grasped and the dangerous situation can be easily avoided in offline teaching work. To improve the efficiency of off-line teaching work.

In order to achieve the above object, the present invention employs the following technical means.
The offline teaching data creation method according to the present invention stores three-dimensional data including a workpiece and a robot that performs a work on the workpiece, creates teaching data for the robot by using the three-dimensional data, A teaching data creation device that calculates a virtual reaction force according to the distance between the robot and the workpiece, and a movement and rotation of a control point of the robot connected to the teaching data creation device and within the three-dimensional data An off-line teaching data creation system having an input / output device capable of inputting and outputting a virtual reaction force calculated by the teaching data creation device. In the teaching data creation device, the robot and workpiece A reaction force calculation step for calculating a resultant force of a virtual reaction force that is inversely proportional to the distance of the distance, and a temporary force calculated in the reaction force calculation step. The magnitude and direction of the resultant force of the diamagnetic force while running, and the reaction force output step of outputting the input-output device, characterized by creating teaching data of the robot.

Preferably, the reaction force calculating step includes a distance between the robot and an object other than the workpiece that may interfere with the robot in addition to a resultant force of a virtual reaction force that is inversely proportional to the distance between the robot and the workpiece. It is preferable to calculate a resultant force of a virtual reaction force that is inversely proportional to.
Preferably, the reaction force calculating step calculates a resultant force of a virtual reaction force that is inversely proportional to the square of the distance.

  Another offline teaching data creation method according to the present invention stores three-dimensional data including a workpiece and a robot that performs work on the workpiece, and creates the teaching data for the robot by using the three-dimensional data. In addition, a teaching data creation device that calculates a virtual reaction force according to the distance between the robot and the workpiece, and a movement of a control point of the robot connected to the teaching data creation device and within the three-dimensional data And an offline input / output device that can output a virtual reaction force calculated by the teaching data generation device, and can be used to input the rotation. In the teaching data generation device, the robot When the distance between the workpiece and the workpiece becomes less than the danger distance that may cause interference, a virtual reaction in a direction to avoid the interference situation A reaction force calculating step for calculating a resultant force of the output force, and a reaction force output step for outputting the magnitude and direction of the resultant force of the virtual reaction force calculated in the reaction force calculating step to the input / output device. The robot teaching data is created.

Preferably, in the reaction force calculation step, a distance between the robot and an object other than a workpiece that may interfere with the robot interferes with the resultant force of the virtual reaction force in a direction to avoid the interference situation. It is preferable to calculate a virtual reaction force in a direction that avoids the interference situation when the distance becomes equal to or less than the danger distance where the danger occurs.
Preferably, in the reaction force calculation step, a plurality of the danger distances are provided in stages, and a virtual reaction force corresponding to the stages of the plurality of danger distances is calculated.

Furthermore, preferably, in the three-dimensional data, the robot control point is constrained by at least one of a point, a line, and a surface, and then the robot control point is moved and rotated in an unconstrained direction. In teaching the position and posture of the robot,
The reaction force calculating step may calculate a resultant force of a virtual reaction force in the unconstrained direction.

  The offline teaching data creation system according to the present invention stores three-dimensional data including a workpiece and a robot that performs work on the workpiece, creates teaching data for the robot by using the three-dimensional data, and A teaching data creation device for executing each step in the off-line teaching data creation method, a teaching data creation device connected to the teaching data creation device and capable of inputting movement and rotation of a control point of the robot in the three-dimensional data; And an input / output device capable of outputting a virtual reaction force calculated by the teaching data creation apparatus.

In the present invention having the above-described means, the distance to the workpiece and the surrounding environment is calculated for a part of the robot arm and the processing tool, and the virtual reaction force corresponding to the distance is calculated before the collision state is reached. To the input / output device. Thereby, the teaching point of the robot can be efficiently created while avoiding the collision.
In addition, by combining vectors corresponding to reaction forces in various directions generated according to the distance from the surrounding environment, the reaction force is almost offset and the place where the reaction force is small , It can be detected at a certain distance from the surrounding environment. This makes it possible to notify the operator of a position / posture at a reasonably safe distance from the surrounding environment, and the operator can easily determine whether the situation is safe or dangerous while performing the teaching operation. can do.

For example, when the tip of the torch in the welding operation is made to follow the weld line of the workpiece, the distance between the workpiece having the weld line and the tip of the torch approaches. In this case, if a reaction force according to the distance from the surrounding environment is simply returned, a virtual force is generated in the direction away from the weld line, making it difficult to create a teaching point at the target position / posture. .
In response to this, by specifying geometric information that constrains the tip of the processing tool, for example, a line, a point, or a surface, the robot keeps the processing tool tip constrained at the specified geometric position. Can be changed in a direction to avoid the interference and position. By returning to the input / output device the reaction force calculated with components other than the position / posture components that realize the constraint of the tool tip, the operator can keep the tool tip at the target position, line, or surface. It is possible to easily determine and set the safe posture of the robot.

  By using the offline teaching data creation method and the offline teaching data creation system according to the present invention, it is possible to sensuously grasp a dangerous situation where interference may occur in the offline teaching work, and to easily identify the dangerous situation. Information can be provided to the operator so that it can be avoided, and the efficiency of teaching work can be improved.

It is a figure which shows schematic structure of the offline teaching data creation system by embodiment of this invention. It is a figure which shows the view of the calculation method of the virtual reaction force fi which generate | occur | produces with a certain mass point of a robot arm. It is a figure which shows the relationship between the virtual reaction force fi which acts on each mass point of the robot arm which approached in the workpiece | work, the translational force F which acts on a robot arm, and the rotational force N. It is a figure which illustrates the relationship between the distance to a workpiece | work and the magnitude | size of the virtual reaction force fi to generate | occur | produce. It is a figure which illustrates the attitude | position change of a robot arm when restraining the welding torch front-end | tip. It is the flowchart which showed the procedure of the teaching point creation work in this embodiment.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the following description, the same components are denoted by the same reference numerals. Further, the same components have the same names and functions. Therefore, the detailed description about the same thing is not repeated.
An offline teaching data creation system according to an embodiment of the present invention will be described with reference to the drawings.

First, the overall configuration of the robot system 1 according to the present embodiment will be described.
As shown in FIG. 1, a robot system 1 includes a robot 2 (welding robot 2) that performs a welding operation, a control device 4 that includes a teaching pendant 3, and a teaching data creation device that includes an information processing device such as a personal computer. 5 and the like. The welding robot 2 is a vertical articulated 6-axis industrial robot, and a welding tool 6 composed of a welding torch or the like is provided at the tip thereof. The welding robot 2 may be mounted on a slider (not shown) that moves itself.

  The control device 4 controls the operation of the welding robot 2 according to a teaching program taught in advance. The teaching program may be created using the teaching pendant 3 connected to the control device 4 or may be created offline using the teaching data creation device 5. In any case, the teaching program is created in advance before the welding robot 2 actually performs the welding operation. The teaching program created using the teaching data creation device 5 is transferred to the control device 4 via a medium or the like in which data is magnetically or electrically stored, or transferred to the control device 4 by data communication.

  A teaching data creation device 5 as a teaching data creation device includes a display capable of graphic display as a display device, and includes a keyboard, a mouse, and an input / output device 7 (details will be described later) as input devices. Further, the teaching data creation device 5 includes a reading device or a communication device in order to capture CAD information for creating three-dimensional data of the workpiece W. In this way, the input / output device 7 and various devices are connected to the teaching data creation device 5 to constitute an offline teaching data creation system.

The teaching data creation device 5 stores three-dimensional data including a workpiece W and a welding robot 2 that performs a welding operation on the workpiece W, and an operator (operator) M inputs the three-dimensional data using the three-dimensional data. By operating the apparatus, teaching data for the welding robot 2 can be created.
Further, in the case of the present embodiment, the teaching data creation device 5 calculates a virtual reaction force according to the distance between the welding robot 2 and the workpiece W, and the calculated reaction force is input to the input / output device 7. Is configured to return to

By the way, as the input / output device 7, FALCON (registered trademark) manufactured by NOVINT (NOVINT FALCON website, http://home.novint.com/products/novint) falcon.php), PHANTOM (http://www.ddd.co.jp/product/phantom/) and SPIDER (http://www.ddd.co.jp/product/spidar) Input / output devices such as /index.html) can be used.

In this embodiment, the above-described FALCON manufactured by NOVINT is used as the input / output device 7. Hereinafter, the description will be made with the input / output device 7 in mind.
The input / output device 7 includes an input grip 8, and three-dimensional input is possible with respect to the teaching data creation device 5 by moving the input grip 8 in three dimensions, up and down, left and right, and front and rear. Further, the input / output device 7 generates a reaction force (force feedback) for each dimension input based on an instruction from the teaching data creation device 5.

  In this embodiment, the dimensions that can be input by the input / output device 7 are three dimensions (robot base coordinates) of the X-axis direction, the Y-axis direction, and the Z-axis direction of the three-dimensional data displayed on the display of the teaching data creation device 5. X, Y, Z). At this time, the dimensions of the reaction force that can be generated by the input / output device 7 are the three dimensions of the X-axis direction, the Y-axis direction, and the Z-axis direction of the three-dimensional data, similar to the input dimension. By adopting other input / output devices, it is possible to perform input / output in a maximum of 6 dimensions including rotations (α, β, γ) around each coordinate axis.

  The input / output device 7 of this embodiment moves and rotates the tip of the welding tool 6 attached to the tip of the welding robot 2 in the three-dimensional data by moving the input grip 8 (control point of the welding robot 2). Input is possible. Further, the input / output device 7 can generate a reaction force having a magnitude instructed from the teaching data creation device 5. Thereby, it becomes difficult to move the input grip 8 in the direction against the reaction force, and the input against the reaction force can be suppressed.

Needless to say, the input / output device 7 is not limited to FALCON manufactured by NOVINT. As long as the above-described input / output device is available, a PHANTOM and SPIDER manufactured by Inet and other input / output devices can be used as the input / output device 7.
In the offline teaching data creation system having the above-described configuration, the teaching data creation device 5 calculates a reaction force of a virtual reaction force fi (virtual reaction force) that is inversely proportional to the distance between the welding robot 2 and the workpiece W. The robot teaching data is created while executing the force calculation step and the reaction force output step of outputting the magnitude and direction of the resultant force of the virtual reaction force fi calculated in the reaction force calculation step to the input / output device 7.

  In creating the teaching data, a force having a magnitude corresponding to the distance between the mass point set in the welding robot 2 in the three-dimensional data and the workpiece W is calculated as a virtual reaction force fi acting on the mass point. . Further, the off-line teaching data creation system is characterized in that the resultant resultant force of the virtual reaction force fi is output to the input / output device 7 as a force acting in the direction opposite to the workpiece W at the mass point.

This virtual reaction force fi is not a force generated when the mass point set in the welding robot 2 interferes with the workpiece W, but depends on the approach distance between the mass point and the workpiece W before the mass point interferes with the workpiece W. This is the force calculated by the teaching data creation device 5.
In addition, the mass point set in the welding robot 2 here is a point that is convex on the surface of the model of the welding robot 2 in the three-dimensional data and is set in advance in a portion that easily interferes with the workpiece W. . This mass point may be set at all the vertices forming the outer shape of the model of the welding robot 2 or may be set at the vertices of the surface portion of the calculation mesh created by stress calculation or the like.

In the present embodiment, the mass point is set as described above from the balance between the moving speed of the welding robot 2 and the time required for the calculation in the teaching data creation device 5.
With the input / output device 7 having such a configuration, it is possible to suppress input to the teaching data creation apparatus 5 or to output a reaction force against the input to call attention. Processing performed by the teaching data creation device 5 to generate a reaction force on the input / output device 7 will be described in detail below.

A method of calculating the virtual reaction force fi acting on the mass point will be described with reference to FIGS.
FIG. 2 is a diagram illustrating the concept of a method for calculating the virtual reaction force fi generated at a certain point of the welding robot 2.
As shown in FIG. 2, for a certain mass point of the model of the welding robot 2, a vector (isotropic vector) is set so as to be directed from the mass point in all directions in the three-dimensional space. These isotropic vectors are required not only to have no deviation in direction but also to have sufficient resolution to obtain high calculation accuracy. Therefore, for example, a vector is set in the direction of the center of each surface of the regular n-hedron around the target mass point. In this embodiment, a vector in the center direction of each surface of the regular icosahedron is set.

  The shortest distance between the mass point in each vector set in this way and the workpiece W or the surrounding environment is calculated temporarily, and the size of each vector is inversely proportional to the square of the shortest distance from the workpiece W. The ambient environment here is “an object other than the workpiece W that the welding robot 2 may interfere with”, for example, a mounting table or a positioner on which the workpiece W is mounted, or gripping the workpiece W For example, a clamp member is applicable.

  As shown in FIG. 4A, the size of the isotropic vector decreases in inverse proportion to the square of the distance l as the distance from the interference area representing the workpiece W increases. When the distance to the workpiece W is closer than the dangerous distance at which the danger of interference with the workpiece W occurs, the size of the isotropic vector is set to a constant value that is lower than a preset upper limit value. This constant value is a value obtained by multiplying a preset upper limit value by an arbitrary ratio. In this embodiment, the upper limit value is multiplied by, for example, 80% in consideration of the operability of the input / output device 7. ing.

When the workpiece W does not exist in the direction of the vector from the mass point, the size of the vector is calculated as zero.
A combined vector of each vector obtained by the above calculation is obtained, and the obtained combined vector is set as a vector of the virtual reaction force fi generated at the mass point. The vector of the virtual reaction force fi generated at the mass point i is expressed by the following equation (1), where V _j is the direction of the isotropic vector and l _j is the distance from the workpiece W and the surrounding environment at that time. . Note that a minus sign is attached to the right side of equation (1).

In this way, the magnitude of the isotropic vector around the mass point is made inversely proportional to the square of the distance of the mass point from the workpiece W, and the vector of the virtual reaction force fi at the mass point i is obtained by the equation (1). The vector of the virtual reaction force fi faces away from the workpiece W.
As shown in FIG. 4A, the size of the isotropic vector at the mass point i may be continuously changed in inverse proportion to the square of the distance to the workpiece W. As shown, it may be changed step by step.

  FIG. 4B shows an isotropic vector size change in the case where a plurality of danger distances at which a danger of interference with the workpiece W occurs are provided in stages. When the distance between the mass point and the workpiece W is greater than the safe distance at which no danger of interference occurs, the size of the isotropic vector is set to zero. When the distance between the mass point and the workpiece W is equal to or less than the first danger distance less than the safety distance, the magnitude of the isotropic vector is set to a constant value of a predetermined magnitude. When the mass point further approaches the workpiece W and becomes equal to or less than the second danger distance, the size of the isotropic vector is set to a constant value larger than the value less than or equal to the first danger distance. The size of the isotropic vector below the second danger distance is set to a constant value below a preset upper limit value. This constant value is a value obtained by multiplying a preset upper limit value by an arbitrary ratio. In this embodiment, the upper limit value is multiplied by, for example, 80% in consideration of the operability of the input / output device 7. ing.

  By combining isotropic vectors whose magnitudes are obtained in this way, a virtual that changes stepwise according to a plurality of danger distances provided stepwise regardless of the above-described equation (1). The reaction force fi can also be calculated. If the virtual reaction force fi at the mass point i changes stepwise, as a result, the change in the reaction force felt by the operator M via the input / output device 7 also becomes stepwise, and the operator M reliably changes the virtual reaction force fi. Is expected to be detected.

  When the force that can be generated by the input / output device 7 is weak, or when it is difficult for the operator M to feel the reaction force that continuously changes in FIG. 4A, as shown in FIG. It is preferable to generate a reaction force that changes stepwise. In other words, if the stepwise reaction force shown in FIG. 4B is returned to the input / output device 7, an intuitive and easy-to-understand force is generated for the operator, and the input / output device 7 is ergonomic. It can be an optimal operation device from a general viewpoint.

  The welding robot 2 is provided with a plurality of mass points, and a virtual reaction force fi acting on each mass point is calculated based on the equation (1). Although the virtual reaction force fi acting on each mass point is different in magnitude and direction, if the welding robot 2 is regarded as a rigid body, the translational force and the rotational force generated in the welding robot 2 can be derived. The derived translational force and rotational force are converted into a force generated at a control point of the welding robot 2 (the tip of the welding tool 6 in this embodiment).

FIG. 3 shows the relationship between the virtual reaction force fi acting on each mass point of the welding robot 2 that has entered the workpiece W, and the translational force F and the rotational force N acting on a certain control point of the welding robot 2.
In FIG. 3A, the arrangement when the welding robot 2 that has entered the workpiece W is viewed from the side with respect to the entry direction is shown in the left figure, and the arrangement when viewed from the front in the entry direction is shown in the right figure. Each is shown. The left diagram in FIG. 3A shows that virtual reaction forces f1 to f3 are acting on three mass points of the welding robot 2. These virtual reaction forces f <b> 1 to f <b> 3 work as a component force as shown in the right diagram of FIG. If the following equations (2) and (3) are used, the translation acting on the control point of the welding robot 2 when the welding robot 2 is regarded as a rigid body from the component of the virtual reaction force fi acting on the mass point of the welding robot 2 The force F and the rotational force N can be obtained.

  When the virtual reaction force fi is used at each mass point of the welding robot 2 and the welding robot 2 is regarded as a rigid body and the number of mass points is m, the translational force vector F, which is the translational force F acting on the control point, is expressed by the following equation: (2).

  In addition, the rotational force N acting on the control point is expressed by the following two equations: the vector of the virtual reaction force fi and the position vector ui at each mass point, as shown in the following equation (3). It can be expressed by the composition of the outer product of.

  As described above, the translational force F and the rotational force N acting on the control point of the welding robot 2 are obtained from the virtual reaction force fi acting on each mass point of the welding robot 2 using the equations (2) and (3). The teaching data creation device 5 converts the translational force F and the rotational force N into a force acting on the control point of the welding robot 2 and instructs the input / output device 7 of a vector of the force acting on the control point. The device 7 generates a reaction force corresponding to the indicated vector with respect to the movement of the input grip 8. The operator can sensuously detect a state in which the welding robot 2 is likely to interfere with the workpiece W by the reaction force generated by the input device.

  At this time, the teaching data creating apparatus 5 is such that the value obtained by multiplying the maximum reaction force that can be generated by the input / output device 7 by a predetermined ratio becomes the upper limit of the reaction force that is actually generated by the input / output device 7. Next, the input vector 7 is instructed by multiplying the force vector acting on the control point of the welding robot 2 by an appropriate magnification. Here, the predetermined ratio by which the maximum reaction force of the input / output device 7 is multiplied is an arbitrary value. In the present embodiment, for example, 80% is added to the maximum reaction force in consideration of the operability of the input / output device 7. Multiply.

  3B, when the operator operates the input grip 8 so as not to oppose the reaction force of the input / output device 7 as much as possible, the control point of the welding robot 2 is indicated by a dotted line in the workpiece W. FIG. 3 is guided to the arrangement of FIG. 3B indicated by a solid line in the workpiece W. The risk of the control point of the welding robot 2 interfering with the workpiece W is eliminated by the arrangement shown in FIG.

Not only this, but the operator M can sense the force according to the degree of approach between the welding robot 2 and the workpiece W, so that the interference with the workpiece W and the isotropic distance from the workpiece W can be instantly known. Therefore, the operator M can confirm the graphic screen displayed on the display with the minimum necessary amount, and can easily determine whether or not the teaching point can be created at the current position.
As described above, the offline teaching data creation system according to the present embodiment calculates the force acting on the control point of the welding robot 2 and causes the input / output device 7 to generate a reaction force.

The teaching work using the offline teaching data creation system will be described below with reference to FIG. The teaching work here refers to creating a teaching point while moving and rotating the control point of the welding robot 2, for example, the tip of the welding torch of the welding robot 2, using the input / output device 7 that generates a reaction force. It is.
First, the teaching data creation device 5 displays the three-dimensional data of the welding robot 2 and the workpiece W stored in the storage device on the display.

  Next, the operator M who creates teaching data operates the input grip 8 of the input / output device 7 to move the control point of the welding robot 2. The teaching data creation device 5 detects the amount of change in the position of the input grip 8 and moves and rotates part or all of the position and posture of the welding robot 2 associated with the input grip 8 according to the amount of change. As a result, the control point of the welding robot 2 in the three-dimensional data displayed on the display is moved and rotated to change the position and posture of the welding robot 2 (step S1).

In response to the movement of the control point of the welding robot 2 in step S1, the teaching data creation device 5 calculates a virtual reaction force fi generated at each mass point provided in the welding robot 2 (step S2, reaction force calculation step). ).
Based on the virtual reaction force fi calculated in step S2, the teaching data creation device 5 derives the translational force F and the rotational force N generated in the welding robot 2 (FIG. 6, step S3).

The teaching data creation device 5 converts the translational force F and the rotational force N derived in step S3 into a force generated at a control point of the welding robot 2, and sends a force vector generated at the control point to the input / output device 7. Instruct. The input / output device 7 generates a reaction force corresponding to the direction and size of the instructed vector (step S4, reaction force output step).
The operator M moves and rotates the control point of the welding robot 2 to a desired position while referring to the reaction force generated by the input / output device 7 and the three-dimensional data displayed on the display of the teaching data creation device 5. . The operator M confirms the interference between the welding robot 2 and the workpiece W while moving the control point of the welding robot 2, and determines whether or not to create a teaching point (step S5).

When the teaching point is not created, the offline teaching data creation system returns to step S1 and repeats the process up to step S4. When the teaching point is created, the system proceeds to step S6.
In step S5, when the operator M determines that there is no interference between the welding robot 2 and the workpiece W and decides to create a teaching point, the teaching data creation device 5 determines the current position and designation of the welding robot 2 as the teaching point. (Step S6).

When the registration in step S6 is completed, the operator M determines whether or not to continue the current teaching work. When the teaching work is continued, the teaching data creation device 5 returns the process to step S1, and when the teaching work is not continued, the current teaching work is ended (step S7).
As described above, in the offline teaching data creation system according to the present embodiment, the virtual reaction force fi generated at each mass point provided in the welding robot 2 is considered. However, in the teaching of work performed while a part of the robot and the workpiece W are in contact with each other, such as welding, an undesired reaction force of the operator M may be generated in the input / output device 7.

That is, in the welding operation, since the tip of the welding torch of the welding robot 2 contacts the workpiece W on the welding line, when the force acting on the control point of the welding robot 2 is simply calculated, the direction in which the tip of the welding torch moves away from the workpiece W Reaction force may be generated. Then, it becomes impossible to create and edit teaching points on the weld line easily.
Therefore, as shown in FIG. 5, the tip of the welding torch attached to the welding robot 2 is set as a control point of the welding robot 2, and the control point of the welding robot 2 is set so that this control point is arranged on the welding line. It can be constrained. That is, the control point of the welding robot 2 is constrained by any of a point, a line, and a surface in the three-dimensional data so as not to leave the welding line.

That is, if the control point of the welding robot 2 is constrained with a point, the control point is constrained with respect to translational motion, and the degree of freedom that is not constrained is only rotational motion (swivel motion) at that point.
Moreover, if the control point of the welding robot 2 is constrained by a line, the degree of freedom of the control point is only a one-dimensional translational movement on the line and a rotational movement on the line.
Finally, if the control point of the welding robot 2 is constrained by a surface, the degree of freedom of the control point is only a two-dimensional translational motion on the surface and a rotational motion on the surface.

That is, restraining the control point of the welding robot 2 means limiting the degree of freedom of the control point of the welding robot 2.
For example, as shown in FIG. 5A, the tip of the welding torch is used as a control point, and this control point is constrained on the weld line so as not to deviate from the weld line. Then, if a reaction force is generated in the direction indicated by the arrow at the control point of the welding robot 2, the operator M operates the input / output device 7 to control the welding robot 2 in a direction to cancel the generated reaction force. Move and rotate the point.

As shown in FIG. 5B, the welding robot 2 moves to a position where interference with the workpiece W can be avoided while restraining the control point on the welding line by this movement and rotation.
In addition, in step S4 of FIG. 6, a restriction is set so that the force in the direction perpendicular to the weld line is zero with respect to this control point, which is the tip of the welding torch. Thereby, the offline teaching data creation system according to the present embodiment can allow the operator to easily recognize interference other than the contact portion even for the contact work such as welding.

  By the way, it should be thought that embodiment disclosed this time is an illustration and restrictive at no points. In particular, in the embodiment disclosed this time, matters that are not explicitly disclosed, such as operating conditions and measurement conditions, various parameters, dimensions, weights, volumes, and the like of a component deviate from a range that is normally implemented by those skilled in the art. Instead, values that can be easily assumed by those skilled in the art are employed.

  In the above-described embodiment, the tip of the welding torch can be moved by the input / output device 7. Instead, the attitude of the welding torch can be changed by the input / output device 7. Even in this case, a technique of “calculating a virtual reaction force according to the distance between the welding robot 2 and the workpiece W and returning the calculated reaction force to the input / output device 7” of the present invention is employed. Thus, the operator can grasp the dangerous situation in which interference may occur sensuously and can easily create the teaching data while easily avoiding the dangerous situation.

In the above-described embodiment, the magnitude of the virtual reaction force fi is inversely proportional to the square of the distance from the workpiece W, but is not limited to the square, and may be inversely proportional to the first power or the power of the third power or higher.
Furthermore, in the above-described embodiment, the welding robot has been described as an example. However, the present invention also applies to the creation of teaching data for stitch operations such as sealing processing for attaching a sealant to the workpiece W and painting processing for applying paint. It is possible to apply.

DESCRIPTION OF SYMBOLS 1 Robot system 2 Welding robot 3 Teaching pendant 4 Control apparatus 5 Teaching data creation apparatus 6 Welding torch 7 Input / output device 8 Input grip M Operator W Workpiece

Claims (8)

3D data including a workpiece and a robot that performs work on the workpiece is stored, teaching data for the robot is created by using the 3D data, and a virtual according to the distance between the robot and the workpiece A teaching data creation device for calculating an effective reaction force;
Connected to the teaching data creation device, can input the movement and rotation of the robot control point in the three-dimensional data, and can output the virtual reaction force calculated by the teaching data creation device. An offline teaching data creation system having an output device,
In the teaching data creation device,
A reaction force calculating step for calculating a resultant force of a virtual reaction force inversely proportional to the distance between the robot and the workpiece;
A reaction force output step of outputting the magnitude and direction of the resultant force of the virtual reaction force calculated in the reaction force calculation step to the input / output device;
Offline teaching data creation method for creating robot teaching data while executing   The reaction force calculation step is inversely proportional to the distance between the robot and an object other than the workpiece that may interfere with the robot, in addition to the resultant force of the virtual reaction force that is inversely proportional to the distance between the robot and the workpiece. 2. The offline teaching data creation method according to claim 1, wherein a resultant force of a virtual reaction force is calculated.   The off-line teaching data creation method according to claim 1, wherein the reaction force calculation step calculates a resultant force of a virtual reaction force that is inversely proportional to the square of the distance. 3D data including a workpiece and a robot that performs work on the workpiece is stored, teaching data for the robot is created by using the 3D data, and a virtual according to the distance between the robot and the workpiece A teaching data creation device for calculating an effective reaction force;
Connected to the teaching data creation device, can input the movement and rotation of the robot control point in the three-dimensional data, and can output the virtual reaction force calculated by the teaching data creation device. An offline teaching data creation system having an output device,
In the teaching data creation device,
A reaction force calculating step for calculating a resultant force of a virtual reaction force in a direction to avoid the interference situation when the distance between the robot and the workpiece is equal to or less than a dangerous distance in which a danger of interference occurs;
A reaction force output step of outputting the magnitude and direction of the resultant force of the virtual reaction force calculated in the reaction force calculation step to the input / output device;
Offline teaching data creation method for creating robot teaching data while executing   In the reaction force calculation step, in addition to the resultant force of the virtual reaction force in the direction of avoiding the interference situation, the distance between the robot and an object other than the workpiece that may interfere with the robot has a risk of interference. 5. The off-line teaching data creation method according to claim 4, wherein a virtual reaction force in a direction to avoid the interference situation is calculated when the distance becomes less than the danger distance to be generated.   6. The off-line teaching according to claim 4 or 5, wherein the reaction force calculation step calculates a virtual reaction force corresponding to the plurality of danger distances by providing a plurality of danger distances in stages. Data creation method. In the three-dimensional data, the robot control point is constrained by at least one of a point, a line, and a surface, and then the robot control point is moved and rotated in an unconstrained direction. When teaching posture,
The off-line teaching data creation method according to claim 1, wherein the reaction force calculation step calculates a resultant force of the virtual reaction force in the unconstrained direction. 8. The storage device according to claim 1, wherein three-dimensional data including a workpiece and a robot that performs work on the workpiece is stored, and teaching data for the robot is created by using the three-dimensional data. A teaching data creation device for executing each step in the offline teaching data creation method;
Connected to the teaching data creation device, can input the movement and rotation of the robot control point in the three-dimensional data, and can output the virtual reaction force calculated by the teaching data creation device. An output device;
An off-line teaching data creation system.