JP2000141259A - Robot control device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To facilitate teaching even in case when a teaching portion is hard to visually observe. SOLUTION: A stopping condition, whether to retreat or not, a direction and moving quantity in case of retreating, etc., are previously set in a robot control device. As the stopping condition, there is a detection signal from a sensor to detect contact of a tool and an object, a load applied on a robot is more than a threshold value, moving distance after starting of manual delivery exceeds a set value, etc. Manual delivery is started (d1) by operating a signal motion direction key. The control device judges whether the set stopping condition is established (d2), and in the case when it is established, a robot position at the time is memorized (d3). The idling robot is returned to this memorized position (d4). When it is set to retreat it (d5), the robot is moved by set quantity in the set direction, and thereafter, it is stopped (d6, d7). Teaching is facilitated as manual deliver is automatically stopped when the tool and the object make contact with each other.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a robot control device, and more particularly, to a robot control device for simplifying a teaching operation.

[0002]

2. Description of the Related Art As a method of teaching a work operation to a robot, there is a direct teaching method in which the robot is manually moved to teach each teaching point or the like. In this method, a worker selects and teaches a teaching point or the like while observing a positional relationship between a tool attached to a wrist of a robot and a work target.

However, for example, when teaching the lower part of the body of an automobile as a spot welding position,
In some cases, the teaching position cannot be visually observed. Conventionally, the teaching point for such a part in which the positional relationship between the tool of the robot and the work target is difficult to see is taught based on the intuition of the worker. In the case of teaching the contact position between the tool and the work target, the degree of contact is determined by the worker, and in places where visual observation is difficult, teaching is performed based on the worker's intuition as described above. There is a method in which a worker teaches while watching a lamp or the like that notifies a contact between a tool and a work object.

[0004] Further, when teaching a position where a robot (tool) is operated in a certain direction from a current position in a certain direction,
Conventionally, a worker performs a manual feed operation while checking the current position of the robot (tool) to operate the robot (tool) to the teaching position, or directly adds the distance to be operated to the current position to directly enter the teaching position. The required method is adopted.

Further, it may be desirable to change the position and orientation of the tool by performing a manual feed operation with respect to the tip of the tool at the position where the tool moves. In such a case, conventionally, the tool coordinate system is reset every time a part where the tool tip point is set moves. Further, when teaching a teaching point by contacting or approaching the tool in a fixed posture with respect to the work target, the tool is operated until the operator reaches a desired posture by manual feeding operation.

[0006]

Relying on the intuition of the operator in teaching a part that is difficult to see visually causes inaccuracy of the teaching position and makes the teaching operation difficult. Also, in the case of teaching the contact position between the work object and the tool, the teaching based on the intuition of the worker or the teaching by the worker while monitoring the lamp for notifying the contact between the work object and the tool is not necessary. Positional variations occur, making accurate teaching work difficult.

[0007] Even when the teaching position is moved in a fixed direction from the current position by a manual operation of an operator or by adding the distance to be operated to the current position to obtain the teaching position, the teaching position varies and There is a disadvantage that the teaching operation becomes complicated. Even when the tool posture is changed based on the tool tip point, the tool coordinate system is reset every time the tool tip point moves, or the tool approaches or contacts the work object in a fixed posture. In such a case, obtaining this posture by manual operation complicates the teaching operation. Accordingly, it is an object of the present invention to improve the above-described problem and to provide a robot control device that assists a teaching operation and facilitates teaching.

[0008]

A robot controller according to the present invention controls each axis of the robot when a detection signal is output from a sensor for detecting contact between a tool attached to the robot and a work object. When the load torque applied to any of the driven motors exceeds the set torque,
When moving a predetermined distance from the start of the manual feed operation, one of the conditions is set in advance in the robot controller as a manual operation stop condition, and monitoring means for monitoring whether the manual operation stop condition is satisfied is provided. In the meantime, when the monitoring means detects that the stop condition is satisfied, the manual feed is automatically stopped. The feed direction of the manual feed operation is
Any of the X, Y, and Z axes of the robot reference coordinate system, the work coordinate system, and the tool coordinate system can be selected. Further, a storage means for storing the position of the robot when the stop condition is satisfied is provided, and the robot coasting from when the stop condition is satisfied to when the robot stops is returned to the position stored in the storage means. At this time, a storage means for setting and storing a direction and a distance to retreat from the position where the stop condition is satisfied is provided. After stopping at the position where the stop condition is satisfied, the storage means is moved by the set distance in the direction stored in the storage means. did.

[0009]

FIG. 1 is a block diagram of a main part of a robot controller according to an embodiment of the present invention, which has the same configuration as a conventional robot controller. A main processor (hereinafter, simply referred to as a processor) 101, a RAM, a ROM, and a non-volatile memory (EE) are provided on a bus denoted by reference numeral 107.
A memory 102 composed of a PROM or the like, a teaching operation panel interface 103, an input / output interface 106 for an external device, and a servo control unit 105 are connected. The teaching operation panel 104 is connected to the teaching operation panel interface 103.

A system program for supporting the basic functions of the robot and the robot controller is stored in a ROM of the memory 102.
Is stored in Further, the operation program of the robot and the related setting data taught according to the application are stored in the nonvolatile memory of the memory 102. The RAM of the memory 102 is used as a storage area for temporarily storing data in various arithmetic processes performed by the processor 101.

The servo control unit 105 includes servo controllers # 1 to # 1.
#N (n: the number obtained by adding the number of movable axes of the tool to the total number of axes of the robot), and is created through arithmetic processing for robot control (trajectory planning and interpolation based on it, inverse transformation, etc.) In response to the movement command, the servo motors constituting the actuators of the respective axis mechanism units of the robot are controlled via the respective servo amplifiers.

The external input / output circuit of the input / output interface 106 is connected to sensors provided on the robot and actuators and sensors of peripheral devices. A sensor for detecting contact is connected.

The configuration of the above-mentioned robot control device is not different from the conventional robot control device. In the present invention, the above-mentioned teaching operation panel 104 is provided with a posture adjusting key, There is a difference in that the control of the posture and the position of the tool can be automatically executed.

FIG. 2 is an explanatory diagram of the teaching operation panel 104 in the present embodiment. The difference between the teaching operation panel 104 and the conventional teaching operation panel is that a posture adjusting key 19 is provided and that a mode for teaching assistance, which will be described later, can be selected with the soft keys 11. It is.
Others are the same as the conventional one. In FIG. 2, only parts related to the present invention are shown, and other parts are omitted. That is, as in the prior art, a display 10 such as an LCD and a soft key 1 for selecting a mode for teaching assistance in connection with the present invention.
1. X, Y, Z in the orthogonal coordinate system of the coordinate system (robot reference coordinate system, work coordinate system, tool coordinate system relatively set from the reference coordinate system) selected by the key 16 for selecting the coordinate system. Axis, a linear operation key 12 for commanding movement in the + and-directions, a rotation operation key 13 for commanding rotation in the + and-directions around the X, Y, and Z axes, and each joint axis J1 of the robot.
Each axis operation key 14 for commanding the operation of J6 in the + and-directions
Is provided. In this embodiment, the robot has six axes. Further, the teaching operation panel 104 is pressed together with the operation keys 12, 13, and 14 as in the prior art, and a shift key 15 for inputting respective commands is provided.
A key 16 for selecting a coordinate system, a mode key 17 for switching between a teaching mode and a reproduction mode, and selecting these setting display screens for setting various coordinate systems and setting parameters,
A function selection key 18 that can be set is provided. In addition to the above, it is provided with various command keys and the like as in the conventional teaching operation panel, but FIG. 2 shows only the key portion directly related to the present invention.

Through manual operation of the teaching operation panel 104, the operator teaches, corrects, registers and sets various parameters of the operation program of the robot, as well as performs the operation of reproducing the taught operation program in the same manner as before.
Execute jog feed, etc. The display is used for instructing the operator, displaying input data, and displaying simulation results.

<Position Adjustment Mode Using One Axis> In this posture adjustment mode, the tool posture is automatically changed so that the relation between the tool attached to the wrist at the tip of the robot arm and the work object becomes a desired relation. Is what you do.
That is, in this posture adjustment mode, one axis is selected from each of the work coordinate system W set for the work object and the tool coordinate system T set for the tool relative to the robot reference coordinate system, The tool posture is automatically changed so that the relationship (intersecting angle) set between the axes is obtained. As shown in FIG. 11 (c), which will be described later, this is suitable for setting the position of the spot welding gun (tool) such that the tip of the spot welding gun (tool) is perpendicular to the plane of the welding position of the work object. is there.

FIG. 3 shows the attitude adjustment mode using one axis.
The process of the processor 101 of the robot controller shown in FIG. FIG. 4 shows an example in which a spot welding gun is used as a tool.

First, as shown in FIG. 4A, a tool coordinate system T and a work coordinate system W are set in advance by operating the function selection key 18 as in the conventional case. In addition, this 1
In the posture alignment mode using axes, the posture is adjusted so that one selected axis in the work coordinate system W and the selected axis in the tool coordinate system T are set to the set intersection angle. X of T,
One of the Y and Z axes, X, Y and Z of the work coordinate system W
One of the axes is selected and set, and the intersection angle between the selected and set axes is set. In the example shown in FIG.
It is assumed that the Z axis is selected as the selected axis in both the tool coordinate system T and the work coordinate system W, and the intersection angle θ is set. Note that if the setting of the intersection angle is 0, it means that the selected axes point in the same direction. In addition, the operation speed at the time of manual feeding for posture adjustment is also set in advance.

Then, the mode key 17 is operated to set the teaching mode, and the operator operates the robot to move the tool 20 to the position where the tool 20 is to be taught with respect to the work object 21. When the user presses 15 and the posture adjustment key 19, the processor 101 starts the processing in FIG.

A unit vector t which is parallel to the axis (Z axis in FIG. 4) of the tool coordinate system T and which passes through the origin of the tool coordinate system T is obtained (see FIG. 4B) (step a1). Next, a unit vector w that passes through the origin of the tool coordinate system T and is parallel to the selected and set axis (the Z axis in FIG. 4) in the work coordinate system W is obtained (see FIG. 4C) (step a2). From the outer product of the unit vectors t and w, a normal vector n passing through the origin of the tool coordinate system T and orthogonal to the vectors t and w is obtained (see FIG. 4D) (step a3).

N = t × w (× is an operator of a cross product) It is determined whether or not the obtained normal vector n is “0” (step a 4). If the normal vector n is not “0”, the step The process proceeds to a8, and if “0”, it means that the unit vectors t and w are parallel, and that the normal vector cannot be uniquely obtained. Therefore, an alarm is generated on the display or the like of the teaching operation panel 104, and the input of the vector n 'passing through the origin of the tool coordinate system T on a plane formed by two axes different from the setting axis of the tool coordinate system is performed. A prompt message is displayed (step a5). In the example shown in FIG. 4, since the Z axis of the tool coordinate system T is set as the selected axis, in this case, the input of the vector n 'passing through the origin of the tool coordinate system T on the XY plane of the tool coordinate system is prompted. However, usually, the X axis or the Y axis may be specified. In the example of FIG. 4, the X axis is specified.

When a vector n 'is input (step a)
6), the vector n 'is set as a normal vector n (step a7), and the process proceeds to step a8. In step a8,
The intersection angle α between the vectors t and w is obtained (see FIG. 4E).
A transformation matrix F that is rotated around the normal vector n by the difference (α−θ) between the obtained intersection angle α and the set target intersection angle θ is obtained (step a9). When the set target intersection angle is “0”, the difference α−θ = α−0 = α.
Thus, a transformation matrix F that makes the vector t coincide with the vector w (in the example of FIG. 4, the Z axis of the tool coordinate system T and the Z axis of the workpiece coordinate system W are made parallel) is obtained.

The coordinate system R of the wrist flange surface at the tip of the robot arm at the current position and orientation of the robot viewed from the reference coordinate system of the robot is obtained, and the coordinate system H of the tool tip viewed from the reference coordinate system of the robot is referred to as the coordinate system R. Tool coordinate system T
(Step a10).

H = R · T Further, the coordinate system H obtained above is multiplied by the transformation matrix F to obtain a coordinate system H ′ of the target alignment position and orientation of the tool (step a11) (see FIG. 4 (f)). ). H ′ = H · F The robot is driven so as to operate at the set operation speed toward the target position / posture H ′ (step a12). In FIG. 4G, the tool posture H before the posture adjustment is indicated by a broken line, and the posture H ′ after the posture adjustment (set target intersection angle θ = 0) is indicated by a solid line.

As described above, the robot is automatically driven so that the selected axis in the tool coordinate system T has a predetermined relationship (set intersection angle θ) with the selected axis in the work coordinate system W. The posture of 20 has a desired relationship with respect to the work object 21.

<Position Adjustment Mode by Coordinate System>
In the posture alignment mode using axes, the robot is automatically driven to change the posture of the tool 20 so that the axes selected in the tool coordinate system T and the work coordinate system W have a predetermined relationship (set intersection angle relationship). However, in the posture alignment mode using the coordinate system, the robot automatically drives the robot so that the tool coordinate system T has a set relative relationship with the work coordinate system W to change the tool posture. It is.

First, a tool coordinate system T and a work coordinate system W are set in the same manner as in the above-described posture adjustment mode using one axis. In addition, the operation speed at the time of manual feeding in alignment is set. Further, a relative relationship to be established between the workpiece coordinate system W and the tool coordinate system T is set. When it is desired to set the rotated work coordinate system to the target posture of the tool coordinate system T, the rotation angles of the work coordinate system around the X, Y, and Z axes are set. Then, by continuously pressing the shift key 15 and the posture adjustment key 19 of the teaching operation panel 104 at the same time, the processor 104 executes the processing of FIG. 5 and automatically changes the tool posture to the target posture.

FIG. 6 is a diagram for explaining the operation in the posture adjustment mode using this coordinate system. FIG. 6A shows a work object (work coordinate system) and a tool (tool coordinate system) before the posture adjustment is performed. System). Shift key 15
When the posture adjustment key 19 is pressed at the same time, first, a conversion matrix F for rotating the work coordinate system W by the set rotation angle is set based on the set rotation angles about the work coordinate system X, Y, and Z axes. Then, the conversion matrix F is multiplied by the work coordinate system W to obtain a converted work coordinate system G (step b2) (see FIG. 6B).

G = W · F Next, the coordinate system R of the wrist flange surface of the tip of the robot arm in the current robot position and orientation viewed from the reference coordinate system of the robot is obtained, and the tool tip viewed from the reference coordinate system of the robot is obtained. The coordinate system H is obtained from the coordinate system R and the tool coordinate system T (step b3).

H = R · T The obtained coordinate systems G and H are taken as posture components Gr and Hr, respectively.
And the position components Gl and Hl, and the posture component Hr of the coordinate system H is replaced with the posture component Gr of the coordinate system G to obtain a new coordinate system H 'of the coordinate system of the tool tip (step b4).
(See FIG. 6 (c)). That is, the coordinate system G and the coordinate system H are expressed by the following equations (1) and (2).

[0031]

(Equation 1)

[0032]

(Equation 2) The posture component Hr of the coordinate system H is replaced with the posture component Gr of the coordinate system G, and the other new coordinate system H ′ is expressed by Equation 3.

[0033]

(Equation 3) The robot is driven at the set operation speed toward the new coordinate system H ′ obtained by the above equation (3), and the tool posture is changed so that the tool coordinate system has a relative relationship set to the work coordinate system. End the posture adjustment operation (step b)
5).

<Coordinate system setting mode on tool movable member>
The coordinate system setting mode on the tool movable member is the tool 2
0 is applied when a servo gun or the like driven by a servomotor and capable of detecting the position of the tool movable section is used. In this coordinate system setting mode, it is assumed that the movable part of the tool 20 is servo-controlled as an additional axis of the robot controller, and that the tool movable part is also controlled by the robot controller. Further, a key may be provided on the teaching operation panel 104 as manual operation means for manually feeding the tool movable section, but this means is omitted in the example shown in FIG.

The tool tip point (hereinafter referred to as TCP)
When it is more convenient to rotate or move the tool with reference to the above, when the tool coordinate system T is set on the tool 20 and the portion where the TCP is set moves, the TCP In addition, the tool coordinate system T is automatically set. Hereinafter, a description will be given with reference to the flowchart of the process performed by the processor 101 of the robot control device illustrated in FIG. 7 and the operation explanatory diagrams illustrated in FIGS. 8 and 9.

First, a reference tool coordinate system T is set for a part of the tool 20. 8A shows an example in which the movable part 20a of the tool 20 is set (an example in which the movable tip of the spot welding gun is set), and FIG. 8A 'shows an example in which the fixed part 20b of the tool 20 is set. 8 and 9, (a) to (c) show the case where the tool coordinate system T is set to the movable part 20 a of the tool 20, and (a ′) to (c ′) show that the tool coordinate system T An example in the case of setting to the fixed part 20b of FIG.

Next, the position O of the movable portion serving as a reference is set with respect to the reference tool coordinate system T set above. FIG.
In (b) and (b '), the reference position O of the movable part is set on the tool coordinate system T with reference to the position of the fixed part on the side where the chip of the movable part is provided.

Further, the moving direction of the movable portion 20a of the tool 20 is set by designating the direction of the X, Y and Z axes of the tool coordinate system T. 8C and 8C, the Z axis of the tool coordinate system T is set. Further, after setting the operation speed in the manual feed operation, the movable portion (movable chip) 20a of the tool 20 is manually fed,
Alternatively, it is moved to a desired position P by executing a program (see FIGS. 9A and 9A). Then, when the shift key 15 and the operation direction key 12 are depressed and a manual feed is commanded based on the tool coordinate system T, the processor 101 of the robot controller starts the processing in FIG.

First, the set tool movable section 20a
From the reference position O to the current position P of the tool movable section 20a (L = PO) (step c1) (FIG. 9)
(B), (b ')), and a transformation matrix F is obtained as a translation sequence of the obtained distance L in the axial direction of the set moving direction (the Z-axis direction in this example) (step c2). Then, a new tool coordinate system T ′ is obtained from the reference coordinate system T of the set tool coordinate system and the conversion matrix F by the following equation (step c3) (see FIGS. 9C and 9C).

T '= TF The manual feed operation in the commanded axial direction is executed based on the obtained new tool coordinate system T' (step c4).
As shown in FIGS. 9B and 9B and FIGS. 9C and 9C, even if the movable portion 20a of the tool 20 moves, the tool coordinate system T after the movement automatically changes. Since the movement in the commanded operation direction is performed based on the obtained and obtained tool coordinate system T ′, it is possible to avoid a problem that the tool 20 and the work object 21 interfere during the movement. .

<Stop Mode Based on Stop Condition> The stop mode based on the stop condition is performed when a certain set stop condition is satisfied while the robot is being moved manually.
The robot operation is automatically stopped. For this purpose, in this embodiment, the conditions for the stop must be set in advance. For example, the stop condition is as follows. (1) A sensor for detecting contact between the tool and the work object is provided, a signal from the sensor is detected via the input / output interface 106, and this is set as a stop condition. (2) The load torque of the servomotor that drives each axis of the robot is detected. When even one axis exceeds the threshold value, it is detected that the tool 20 and the work object 21 are in contact with each other, and this is set as a stop condition. The load torque is detected based on the feedback value of the drive current of the servomotor of the square axis or the torque command value (current command value), and when the feedback value or the torque command value is equal to or larger than the set threshold value, Stop condition. Further, when an observer for estimating the load torque is provided, the stop condition may be set to stop when the load torque estimated by the observer exceeds a threshold value. (3) When the moving distance from the manual feed start point exceeds the set value, the automatic stop is performed. There are various types of stop conditions, but an optimum stop condition is selected according to an application example.
For example, assuming that the above-described determination of the stop conditions (1) to (3) is set in the robot controller, which stop condition is to be selected is set in advance. In addition,
When the stop condition of the above (3) is selected, it is necessary to set a moving distance from a start point to be automatically stopped as a set value.

Further, the operation speed during the manual operation is set, and after the stop condition is satisfied, it is set whether or not to operate in the specified amount and in the specified direction from the stop position. Select and set the coordinate system (reference coordinate system of the robot, work coordinate system, tool coordinate system, etc.) as the reference of the operation direction, and set any of the X, Y, Z axes of this selected coordinate system as the operation direction And the moving distance is also set.

As described above, after the stop condition, the operation speed, and whether or not the evacuation is performed after the stop condition is satisfied, the evacuation direction and the amount of the evacuation are set, and then the shift key 15 and the operation direction key 12 or 13 are depressed. , If you command manual feed,
The processor 101 of the robot control device starts the processing in FIG.

The processor 101 operates the operation direction keys 12,
A movement command for moving at the set operation speed in the operation direction instructed in step 13 is output to move the robot at the set operation speed (step d1), and it is determined whether a stop condition is satisfied (step d2). If not, it is determined whether the shift key 15 or the operation direction keys 12, 13 have been released (step d8).
Again (return to step d1, steps d1, d2, d8
Is repeatedly executed. If the shift key 15 or the operation direction keys 12 and 13 are released before it is detected that the stop condition is satisfied, the robot operation is stopped (step d7).

When the stop condition is satisfied, that is, when the stop condition of (1) is set, the contact detection signal from the sensor is input to the input / output interface 106 or the processor 101 When it is detected that the contact detection signal is input, the position at this time is stored, and the manual feed operation of the robot is automatically stopped (shift key 15 and operation direction keys 12, 13). (Step d2, d3). When the condition (2) is set as the stop condition, the processor 101 sets the load torque (current feedback value or torque command value, torque observer value, It is determined whether or not the estimated torque value is equal to or greater than a threshold value (step d2). If the load torque of any of the motors is equal to or greater than the threshold value, the stop condition is satisfied and the position at this time is stored and The operation is stopped (step d3).

Further, when the stop condition of the above (3) is set, the processor 101 adds a moving amount of the robot to the register at predetermined intervals after starting the manual movement in step d1, and this addition is performed. The stop condition is determined based on whether the value has reached the set value. When the added value becomes equal to or larger than the set value, the stop condition is satisfied (step d2), the position of the robot at that time is stored, and the robot is stopped (step d3).

Even if a command to stop the robot is output from the robot controller, the robot decays and stops. Therefore, the robot is moved to the position where the stored stop condition is satisfied, and the stop condition is satisfied. Return to the position (step d4). Then, it is determined whether or not the evacuation is set (step d5). If the evacuation is set, the robot is moved by the set amount of movement in the set direction (step d6), and the robot is stopped (step d7). ).
If the retreat is not set, the robot is stopped while stopping at the stop condition position.

The embodiment of the manual feeding assisting the teaching operation according to the present invention has been described above. The robot controller may be provided with any one of the above-described posture adjustment modes and coordinate system setting modes, or may be provided with all of them. Then, a stop mode based on a stop condition is executed while each is called and executed by a soft key or the like.

In the following embodiments, the above-mentioned "posture adjustment mode using one axis", "posture adjustment mode using a coordinate system",
The “coordinate system setting mode on the tool movable member” and the “stop mode according to the stop condition” are stored in the robot controller, and are selected by the soft keys 11 to execute the processing of the selection method.

Since the work coordinate system and the tool coordinate system (the reference tool coordinate system in the "coordinate system setting mode for tool movable member" mode) are common to all modes, the function selection key 1
8 to select a coordinate system setting, and collectively set a work coordinate system and a tool coordinate system for the above four modes for assisting the teaching operation. Also, the set value of the manual operation speed of the teaching assist operation may be set in advance to be common to all modes, or if the manual operation speed is changed after each mode, By operating the key 11, the setting of each mode is called, and each operation speed is set. Further, in the "coordinate system setting mode on the movable tool member", the reference position O must be set. However, such a set value unique to each mode is set by calling each mode setting. Keep it.

<Application Example to Servo Gun> An embodiment applied to a servo gun in which the movable tip is driven by a servomotor or the like for performing spot welding will be described.
In this embodiment, the gun opening / closing direction and the work
It is necessary to teach the attitude of the servo gun 20 so that the hitting plane is vertical. Further, it is necessary to teach the contact position between the fixed tip 20b and the work 21.
Moreover, in the spot welding of a vehicle body, which is generally performed, the lower part of the panel often becomes difficult to see due to the shadow of the vehicle body. Under such circumstances, the teaching assisting method of the present invention is used. The teaching will be described.

First, as shown in FIG. 11A, the robot is manually fed to move the servo gun 20 to a position near the hit point of the work 21. Next, it is necessary to change the attitude of the servo gun so that the opening / closing direction of the servo gun is perpendicular to the hitting surface of the work object. In this case, there are three methods. One is a method using the “coordinate system setting mode on the tool movable member”, and the other is a “one-axis posture adjustment mode” and a “one-axis posture adjustment”. Mode ".

Therefore, as a first method, the teaching operation panel 1
After switching to the “coordinate system setting mode on the tool movable member” using the soft key 04 or the like and moving the tip of the servo gun to move the TCP as close as possible to the work object 21, the gun opening and closing direction is changed to the work object 21. If the rotation operation key 13 is selected so as to be perpendicular to the hitting surface of the robot, and the shift key 15 and the selection rotation operation key 13 are pressed, the processor 101 of the robot control device performs the processing shown in FIG. The robot is operated based on the TCP set at the tip (see FIG. 11B). As a result, the posture of the servo gun 20 can be manually moved such that the opening / closing direction of the servo gun 20 is perpendicular to the striking surface of the work target 21 without interference between the servo gun 20 and the work target 21.

As a second method, when using the "one-axis orientation adjustment mode", select the "one-axis orientation alignment mode" using the soft key 11, and then use the tool coordinate system T for the orientation adjustment. , The axis of the workpiece coordinate system W and its intersection angle θ are set. In the example of FIG. 11C, the Z axis is selected from the tool coordinate system T and the work coordinate system W as the orientation alignment axis, and the intersection angle θ is set to “0” (that is, Z in both coordinate systems). The axes are parallel). Then, when the shift key 15 and the posture adjustment key 19 are pressed, the processor 101 of the robot control device starts the processing shown in FIG. 3, and the Z axis, which is the selected axis of the tool coordinate system T and the work coordinate system W, is The robot is driven so as to have the set intersection angle θ (= 0), and the servo gun 20 is positioned so that the opening / closing direction is perpendicular to the striking surface of the work target 21 (see FIG. 11C).

Further, the "posture alignment mode using coordinate system" is selected, and a rotation angle around each axis of the work coordinate system W which defines the relative relationship between the tool coordinate system T and the work coordinate system W is set.
When the shift key 15 and the posture adjusting key 19 are pressed, the processor 101 executes the processing shown in FIG. 5, and the opening / closing direction of the servo gun 20 is perpendicular to the hitting surface of the work target 21 as shown in FIG. It is positioned so that it becomes. In the example of FIG. 11C, since the tool coordinate system T may be set to the work coordinate system W, the rotation angles around the respective axes to be set are all “0”, and the conversion matrix obtained in step b1 of FIG. F is a unit matrix.

As described above, after the servo gun 20 is positioned so that the opening / closing direction of the servo gun 20 is perpendicular to the hitting surface of the work object 21, the mode is switched to the "stop mode by stop condition", and the stop condition to be monitored is changed. If selection is set and retraction is not performed, and the operation key 12 in the direction in which the fixed tip contacts the work object 21 and the shift key 15 are pressed, the processor 101 of the robot control device will start processing.
0, and automatically stops at the position where the work target 21 and the fixed-side tip 20b of the tool 20 are in contact (and further, at the position moved by the set direction and the moving amount).

<Example of application to air gun> In the case where the spot welding gun is not a servo gun driven by a servo motor, but an air gun that opens and closes with air pressure, the air gun 2
It is necessary that the opening and closing direction of 0 be perpendicular to the hitting surface with respect to the work 21 and that the fixed tip 20a and the work 21 be spaced apart by the distance. Therefore, when the air gun 20 is used, similarly to the servo gun described above, the gun is released and manually fed to an appropriate position near the hit point of the work object 21, and the "posture alignment mode using the coordinate system" is selected. Then, as in the case of the servo gun, the gun opening and closing direction is made perpendicular to the hitting plane, and the "stop mode based on stop conditions" is selected in the same manner as in the case of the servo gun. Thereafter, since it is necessary to separate by a predetermined distance, retreat is selected, and the retreat direction and the retreat movement amount are set. In the example of FIG. 12, the retreat direction is set to the Z-axis direction of the work coordinate system (or the tool coordinate system), and a target movement amount is set. If so, steps d5 and d6 are performed in the processing of FIG. Thus, after contact between the work object 21 and the tool 20, the tool 20 is separated by a set distance and the robot stops.

<Example of Application to Servo Hand> FIG. 13 is an explanatory diagram of an example in which the present invention is applied to the teaching of the gripping position and posture for the hand 20 driven by the servo motor. First, with the hand 20 opened, the robot is manually operated to approach the work object 21 (see FIG. 13A). Next, it is necessary to rotate the hand so that the holding surface of the hand is parallel to the side surface of the work target. This method includes a “one-axis orientation mode” and a “coordinate orientation mode”. , There is a method of using a “coordinate system setting mode on the tool movable member”.

FIG. 13B is an explanatory diagram in the case of using the “coordinate system setting mode on the tool movable member”. First, the TCP set in the movable portion of the hand is manually moved, The work object 21 is brought as close as possible. Then, the mode is switched to the “coordinate system setting mode on tool movable member”, and the rotation direction is selected.
When the shift key 15 and the shift key 15 are pressed, the processor 101 of the robot controller performs the processing shown in FIG. 7 and rotates around the TCP so that the teaching side of the hand 20 and the side of the work object are manually parallel. It can be operated (see FIG. 13B).

FIG. 13 (c) is an explanatory diagram in the case of using the "one-axis attitude adjustment mode" or the "coordinate attitude alignment mode". When the “one-axis orientation matching mode” is applied, for example, an axis parallel to the holding surface of the hand 20 in the tool coordinate system T (the Z axis in FIG. 13C) and a work object in the workpiece coordinate system W An axis parallel to the side surface 21 (the Z axis in FIG. 13C) is selected and its intersection angle is set to “0”.
By pressing the shift key 15 and the posture adjustment key 19,
The processor 101 performs the processing of FIG.
Can be operated so that the teaching side surface of the work object 21 and the side surface of the work object 21 are parallel to each other. When the “posture adjustment mode using the coordinate system” is used, in the example of FIG. 13C, the rotation angles of the work coordinate system W around the X, Y, and Z axes are all “0”. When the shift key 15 and the posture adjustment key 19 are pressed, the processor 101 performs the processing of FIG. 5 and can operate the teaching side of the hand 20 and the side of the work 21 so as to be parallel.

[0061]

According to the present invention, the stop condition is set, and when the stop condition is satisfied, the manual feed is automatically stopped, so that accurate teaching is possible.

[Brief description of the drawings]

FIG. 1 is a main block diagram of an embodiment of the present invention.

FIG. 2 is an explanatory diagram of a teaching operation panel according to the embodiment.

FIG. 3 is a flowchart of a one-axis attitude alignment process used in the embodiment of the present invention.

FIG. 4 is an explanatory diagram of an operation and an action in a posture adjustment process using the same one axis.

FIG. 5 is a flowchart of a posture alignment process using a coordinate system used in an embodiment of the present invention.

FIG. 6 is an explanatory diagram of an operation and an action in a posture adjustment process using the same coordinate system.

FIG. 7 is a flowchart of a coordinate system setting process on a tool movable member used in the embodiment of the present invention.

FIG. 8 is an explanatory diagram of an operation and an action in a coordinate system setting process on the tool movable member.

FIG. 9 is a continuation of the operation and operation explanatory diagram in the coordinate system setting processing on the tool movable member.

FIG. 10 is a flowchart of an automatic manual feed stop process according to the embodiment of the present invention.

FIG. 11 is an explanatory diagram when the embodiment of the present invention is applied to a servo gun that performs spot welding.

FIG. 12 is an explanatory diagram of an operation of retracting after a tool comes into contact with a work object when the embodiment of the present invention is applied to an air gun for performing spot welding.

FIG. 13 is an operation explanatory diagram when the embodiment of the present invention is applied to a hand in which a movable part is driven by a servo system.

[Explanation of symbols]

 Reference Signs List 20 tool 21 work target 20a movable part 20b fixed part 104 teaching operation panel T tool coordinate system W work coordinate system

Claims (4)

[Claims] When a detection signal is output from a sensor that detects a contact between a tool attached to a robot and a work object, a load torque applied to one of the motors driving each axis of the robot. Exceeds a set torque, or when a predetermined distance has been moved from the start of the manual feed operation, one of the following is set in advance in the robot controller as a manual operation stop condition, and monitoring is performed to monitor whether the manual operation stop condition is satisfied. A robot control device comprising: means for automatically stopping manual feeding when the monitoring means detects that a stop condition is satisfied during manual feeding operation. 2. The feed direction of the manual feed operation is represented by X, X or X in a robot reference coordinate system, a work coordinate system or a tool coordinate system.
2. The system according to claim 1, wherein any one of the Y and Z axes can be selected.
The robot control device described in the above. 3. A storage means for storing a position of the robot at the time when the stop condition is satisfied, wherein the robot coasting from the satisfaction of the stop condition to the stop is returned to the position stored in the storage means. The robot control device according to claim 1 or 2, wherein 4. A storage means for setting and storing a direction and a distance to retreat from a position where the stop condition is satisfied, and after stopping at a position where the stop condition is satisfied, moving by a set distance in the direction stored in the storage means. 4. The robot control device according to claim 3, wherein the control is performed.