JPH0911079A - Deburring control method for robot - Google Patents

Abstract

PURPOSE: To prevent inertial running of a deburring tool after overload is detected, to obtain the retreat direction according to the form of a work, and shorten the cycle time of retry operation. CONSTITUTION: A shaft control means 3 drives the respective shafts of a robot according to a movement command from a movement command means 2 to operate a deburring tool 5 fitted to the arm of the robot 4, thereby deburring a work 6. At this time, an overload detecting sensor 7 detects overload applied to the deburring tool 5. A retreat and retry control means 8 causes the shaft control means 3 to forcedly stop the operation of the deburring tool 5 when overload is detected by the overload detecting sensor 7. After the operation of the deburring tool 5 is stopped, the retreat and retry control means 8 causes the shaft control means 3 to retreat the deburring tool 5 in the direction of decreasing the overload.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a robot deburring control system for deburring a work by a robot, and more particularly to a robot deburring control system for detecting an overload on a deburring tool.

[0002]

2. Description of the Related Art When performing deburring work by a robot, if the deburring tool is overloaded, the deburring tool may be damaged and the desired finishing may not be performed. Therefore, conventionally, a force sensor or the like is attached to the robot to detect an overload of the deburring tool, and the movement of the deburring tool is stopped when the overload is detected.

Further, after the deburring tool is stopped, the deburring tool is retracted from the work by a cylinder or the like. Further, so-called retry operation control has been performed in which the workpiece is approached again from the retracted state, grinding is performed, and stop and retract are repeated with detection of an overload. This retry operation control is a control method in which the operation proceeds along a set path while repeating grinding and retreat, and when grinding is completed up to a preset point, the operation is returned to the first starting point and the above operation is repeated.

[0004]

However, in the case of stopping when overload is detected, conventionally, the movement command is simply cut to the servo system. Therefore, even after the movement command is cut, the deburring tool may coast due to the accumulation of the interpolation pulse and the inertial force, which may damage the tool and the work.

Further, since the retracting operation is conventionally set in the absolute coordinate system, it is possible to retract only in a simple direction along the grinding path. For this reason, it is not always possible to retreat in the direction in which the load decreases, and sufficient deburring cannot be performed for workpieces with complicated shapes.

Further, regarding the retry operation, when one cycle of grinding is completed, the operation always returns to the same starting point,
Since the retries were carried out from there, the cycle time was unnecessarily lengthened as it moved at a low speed even to the part where grinding had already been completed.

The present invention has been made in view of the above circumstances, and an object thereof is to provide a deburring control system for a robot capable of preventing coasting of a deburring tool after overload detection. .

A second object of the present invention is to obtain a retracting direction according to the shape of the work. Furthermore, a third object of the present invention is to shorten the cycle time of the retry operation.

[0009]

In order to solve the above problems, the present invention provides a deburring control method for a robot for deburring a workpiece by a robot, comprising: a deburring tool attached to an arm of the robot; ,
Overload detection means for detecting an overload applied to the deburring tool, movement command means for issuing a movement command for each axis of the robot according to a machining program, and each burr for driving each axis of the robot according to the movement command. Axis control means for operating the removal tool, and a forced stop control means for forcibly stopping the operation of the deburring tool with respect to the axis control means when an overload is detected by the overload detection means, A deburring control system for a robot is provided.

According to the second aspect of the present invention, in a deburring control system of a robot for deburring a work by a robot, a deburring tool attached to an arm of the robot and a deburring tool applied to the deburring tool. Overload detection means for detecting a load, movement command means for issuing a movement command for each axis of the robot according to a machining program, and axis control for driving each axis of the robot according to the movement command to operate the deburring tool Means and retreat control means for retreating the deburring tool in a direction to reduce the overload when the overload is detected by the overload detection means. A deburring control method for a robot is provided.

Further, according to a third aspect of the present invention, in a deburring control system of a robot for deburring a work by a robot, a deburring tool attached to an arm of the robot, and a deburring tool applied to the deburring tool. Overload detection means for detecting a load, movement command means for issuing a movement command for each axis of the robot according to a machining program, and axis control for driving each axis of the robot according to the movement command to operate the deburring tool Means for retracting the deburring tool to the axis control means when an overload is detected by the overload detecting means, and the deburring tool retracts by a predetermined retract distance, Retry control means for retrying the deburring tool toward the work, and the retry and retract are repeated, When the deburring operation is performed up to a preset cycle end position, the deburring tool is returned to the deburring start position side, and the deburring operation by the retry control is repeated until the preset deburring stop condition is satisfied. When the deburring tool is returned to the retry cycle control means, the deburring tool is returned to a position closer to the deburring operation starting point by a predetermined amount than the point at which the overload is first detected in the previous cycle, and A deburring control system for a robot is provided, comprising: an execution position control unit that executes the retry from the returned position.

[0012]

The movement command means issues a movement command for each axis of the robot according to the machining program. The axis control means drives each axis of the robot according to this movement command to operate a deburring tool attached to the arm of the robot. At this time, the overload detection means detects an overload on the deburring tool. The forced stop command means forcibly stops the operation of the deburring tool with respect to the axis control means when the overload is detected by the overload detection means.

Further, in the second aspect of the present invention, when the overload is detected by the overload detection means, the retraction control means causes the axis control means to retract the deburring tool in a direction to reduce the overload.

Further, in the third aspect of the present invention, when the deburring tool is retracted by a predetermined retract distance, the retry control means is
Retry the deburring tool toward the work. The retry cycle control means returns the deburring tool to the deburring start position side when the deburring operation is performed up to a preset cycle end position after repeated retries and retraction, and the deburring stop condition set in advance. The deburring operation by the retry control is repeated until it becomes. here,
When the deburring tool is returned, the execution position control means returns the deburring tool to a position closer to the deburring operation start point by a predetermined amount than the point at which the overload was first detected in the previous cycle, and from the returned position. Cause a retry.

[0015]

An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a conceptual diagram of the function of this embodiment. The movement command means 2 issues a movement command for each axis of the robot 4 according to the machining program 1. The axis control means 3 drives each axis of the robot 4 according to this movement command to operate the deburring tool 5 attached to the arm of the robot 4 to deburr the work 6. At this time, the overload detection sensor 7 detects an overload on the deburring tool 5. When the overload detection sensor 7 detects an overload, the evacuation / retry control means 8 causes the axis control means 3 to forcibly stop the operation of the deburring tool 5. After the operation of the deburring tool 5 is stopped, the retraction / retry control means 8 causes the axis control means 3 to retract the deburring tool 5 in a direction to reduce overload.

The retraction / retry control means 8 retries the deburring tool 5 toward the work 6 when the deburring tool 5 retracts by a predetermined retreat distance. When the deburring operation is performed up to the preset cycle end position by repeating the retry and the retraction, the deburring tool 5 is returned to the deburring start position side until the preset deburring stop condition is reached. Repeat the deburring operation by retry control. Here, when the deburring tool 5 returns,
The deburring tool 5 is returned to a position closer to the deburring operation starting point by a predetermined amount than the point where the overload was first detected in the previous cycle, and the retry is executed from the returned position.

FIG. 2 is a diagram showing a schematic configuration of the robot control system of this embodiment. A grinder 11 as a deburring tool is attached to the tip of the arm of the robot 10 via an overload detection sensor 12. The blade 11a of the grinder 11 is rotated by a spindle motor (not shown) to deburr the work 20. When the blade 11a of the grinder 11 receives a load of a certain value or more, the overload detection sensor 12 notifies the robot control device 30 of the load. The robot controller 30 drives each servo motor of the robot 10 to execute the deburring work by the grinder 11.

FIG. 3 is a view showing the schematic arrangement of the detection mechanism of the overload detection sensor 12. Inside the case 121, a swinging member 122 made of a ferromagnetic material and connected to the shaft 11b of the grinder 11 is provided. This swing member 122
Is pressed downward by a spring 123 with an appropriate force,
It is swingable within a range where it abuts on the screws 124 and 125. An electromagnetic coil 126 is provided in the case 121 so as to surround the swing member 122. The electromagnetic coil 126 generates a magnetic force by an electric current supplied from the robot control device 30 side, and the magnetic force holds the left and right neutral states of the swing member 122 with a predetermined force.

A photoelectric switch 127 is provided in the case 121, slightly above the swinging member 122. The photoelectric switch 127 includes a light emitting unit 127a and a light receiving unit 127b. Light emitting unit 127a and light receiving unit 12
7b shows that the light emitted from the light emitting section 127a is the case 12
1 so that the path of light traverses the inside of the rocking member 12
It is provided at a position such that it is included in the two rocking surfaces.

In such an overload detection sensor 12, when the blade 11a of the grinder 11 is loaded with a load larger than a predetermined value due to the grinding resistance, the swing member 122 overcomes the magnetic force of the electromagnetic coil 126 and rotates clockwise in the drawing. Move. Then, the end portion 122 a of the swing member 122 blocks the optical path of the photoelectric switch 127. As a result, the robot control device 30 detects that the blade 11a is overloaded by a predetermined amount or more.

FIG. 4 is a block diagram showing a schematic configuration of the robot controller 30. The robot controller 30 has a processor board 31.
Include a processor 31a, a ROM 31b, and a RAM 31c.
There is. The processor 31a uses the robot controller 30 according to the system program stored in the ROM 31b.
Take control of the whole. The RAM 31c stores various data, and also stores an operation program of the robot 10 and data necessary for deburring control described later. A part of the RAM 31c is configured as a non-volatile memory, and operation programs and various parameters are stored in this non-volatile memory part. The processor board 31 is coupled to the bus 39.

The digital servo control circuit 32 uses the bus 3
9 is coupled to the servo motor 5 via the servo amplifier 33 in response to a movement command from the processor board 31.
1, 52, 53, 54, 55 and 56 are driven. These servo motors are built in the robot 10 and operate each axis of the robot 10. The digital servo control circuit 32 applies counter electromotive force to the servo motors 51, 52, 53, 54, 55, and 56 when the motion command sent together with the movement command from the processor board 31 becomes 0. , Forcibly stop the axis movement.

The serial port 34 is connected to the bus 39, the teaching operation panel 57 with a display, and other RS232C.
It is connected to the device 58. Further, a CRT 36a is connected to the serial port, and the CRT 36a displays a processing state and the like. The digital I / O 35 has
The operation panel 36b is connected.

Digital I / O 35 and analog I / O
A sensor control circuit 40 is connected to O37. The sensor control circuit 40 supplies the current of the value instructed via the analog I / O 37 to the coil 126 of the overload detection sensor 12.
To supply. Further, the sensor control circuit 40 controls the light emission of the light emitting section 127a of the photoelectric switch 127 of the overload detection sensor 12 and monitors the light receiving state (on / off state) of the light receiving section 127b. This light receiving state is sent to the program 31a side via the digital I / O 35.
Teaching data and the like are stored in the large capacity memory 38.

Next, an actual processing example of the deburring control method of this embodiment will be described. FIG. 5 is a diagram showing an outline of the processing procedure of the deburring control system of this embodiment. Work 20
When removing the burr 21, the machining program instructs machining of the straight line path L1 from the start point Ps to the end point Pe, for example. The grinder 11 moves along the linear path L1 from the state where the blade 11a approaches the starting point Ps, and retracts in a direction to reduce the overload each time the overload detection sensor 12 detects the overload. At this time, the grinder 11 is also retracted upward by a preset distance.

When the evacuation is completed in this way, the grinder 11 again moves parallel to the linear path L1 and the work 20
The retry operation is performed against. Thus, the grinder 11
Repeats the evacuation and the retry until it finally arrives at the position Pe ₁ just above the end point Pe.

FIG. 6 is a view for explaining a concrete processing procedure of the deburring control system of this embodiment. Here, the burr 21 of the work 20 shown in FIG. 5 is removed from the start point Ps to the end point Pe.
It is assumed that a command to grind up to is issued. First, if the movement starts from the starting point Ps and an overload is detected at the point P _{10 of the} burr 21, the gran inder 11 forcibly stops the rotation and movement of the blade 11a on the spot. Thereby, the interference with the work due to the inertia of the grinder 11 can be prevented, and the blade 11a can be prevented from being damaged.

At the same time as the movement of the gran inder 11 is stopped, the grand inder 11 is retracted in the direction opposite to the traveling direction. This allows
The blade 11a can always be retracted in a direction that reduces the load on the blade 11a, and deburring of a workpiece having a complicated shape can be easily performed. The retracting direction may be a direction preset in the tool coordinate system. By doing so, even if the direction of the grinder 11 changes, the retreat direction can always be set to a fixed direction with respect to the grinder 11.
Deburring of workpieces with complicated shapes can be performed easily.

The point P, which is the position of the first overload detection,
₁₀ is stored in the RAM 31c or the like. Further, each time an overload is detected, the register set in the RAM 31c or the like is updated with the overload detection number N in the grinding cycle.

When the operation stop mode is set in advance by the parameter, the retreat operation is not performed when the overload is detected, and the rotation and movement of the blade 11a are stopped at the same time.
An alarm is displayed on the CRT 36a or the like.

FIG. 7 is a time chart showing the control timing of the save operation. When the overload detection is turned on (time t ₁ ), the motion command to the servo system is set to 0 to forcibly stop the grinding operation, and at the same time, the retract operation is performed. This saving operation continues from time t ₂ the overload is turned off until a time t ₃ after a predetermined time t _x has elapsed.

Returning to FIG. 6, after the evacuation operation as described above is completed, the grinder 11 also moves upward by a preset offset amount. Therefore, the blade 11a moves at the point P ₁₀
It moves to point P ₁₁ by the retracting operation from. When the point P ₁₁ is reached, the straight line L is rotated while rotating the blade 11a again.
1 is moved in a direction parallel to 1 and the burr 21 is ground (retry operation). Then, when an overload is applied at the point P ₁₂ , it is stopped, retracted, and moved by the offset amount, similarly to the point P _10, and moves to the point P ₁₃ . After that, a retry operation, a save operation, etc. are performed by the same procedure, and the points P _14, P
It moves to ₁₅ and stops moving when it reaches the same coordinate point P ₁₆ (cycle end point) as the end point Pe on the axis parallel to the linear path L1.

After the stop at the point P ₁₆ , the grinding start state is restored via the points P ₁₇ and P ₁₈ . However, in this case, not the starting point Ps, but the point P on the starting point Ps side by the predetermined distance D _O from the point P ₁₀ at which the overload is first detected in the previous cycle.
Return to position ₂₀ . This makes it possible to shorten the movement distance due to the grinding speed each time the cycle is repeated.
Work efficiency is improved.

Further, when entering the next cycle, the grinding speed is set to a speed corresponding to the overload detection number N in the previous cycle. That is, the smaller the overload detection number N, the faster the grinding speed. As a result, work efficiency is further improved.

After that, the grinding cycle is repeated by the same procedure, and when the distance between the point P ₁₆ and the end point Pe becomes equal to or less than the predetermined distance D ₁ , all the work is finished. In this embodiment, the overload detection sensor 1 is used as overload detection means.
However, the overload may be detected by estimating the disturbance load applied to the servomotor side of the robot 10 on the digital servo control circuit 32 side. As is well known, the disturbance load is estimated based on a feedback signal obtained from a position detector such as a pulse coder provided on the servo motor side.

Further, in the present embodiment, the retreating operation is performed after the grinder 11 is forcibly stopped at the same time when the overload is detected. However, the gain of the servo motor of the robot 10 is reduced to reduce at least the load. The servo stiffness in the opposite direction may be reduced. As a result, the load on the grinder 11 can be released without performing the retracting operation.

[0037]

As described above, according to the present invention, the deburring tool attached to the arm of the robot is operated,
When an overload is detected by the overload detection means, the operation of the deburring tool is forcibly stopped, so it is possible to prevent interference with the work due to the inertia force of the deburring tool and prevent damage etc. You can

Further, in the second aspect of the present invention, when the overload detecting means detects the overload, the deburring tool is retracted in the direction of reducing the overload, so that the load on the deburring tool is always reduced. Can be retracted in any direction,
Deburring of workpieces with complicated shapes can be performed easily.

Further, according to the third aspect of the present invention, when the deburring tool is returned, the deburring tool is returned to a position near the deburring operation starting point by a predetermined amount from the point where the overload is first detected in the previous cycle. Since the retry is performed from the returned position, the grinding can be always performed from a point near the burr of the work each time the cycle is repeated.
Therefore, the movement distance depending on the grinding speed can be shortened and the work efficiency is improved.

[Brief description of the drawings]

FIG. 1 is a conceptual diagram of functions of the present embodiment.

FIG. 2 is a diagram showing a schematic configuration of a robot control system of the present embodiment.

FIG. 3 is a diagram showing a schematic configuration of a detection mechanism of an overload detection sensor.

FIG. 4 is a block diagram showing a schematic configuration of a robot controller.

FIG. 5 is a diagram showing an outline of a processing procedure of a deburring control system of the present embodiment.

FIG. 6 is a diagram illustrating a specific processing procedure of the deburring control method of the present embodiment.

FIG. 7 is a time chart showing the control timing of the save operation.

[Explanation of symbols]

 1 Machining program 2 Movement command means 3 Axis control means 4 Robot 5 Deburring tool 6 Work 7 Overload detection sensor 8 Evacuation / retry control means 10 Robot 11 Grinder 11a Blade 12 Overload detection sensor 20 Work 30 Robot controller 31a Processor ( CPU) 31b ROM 31c RAM 32 Digital servo control circuit 33 Servo amplifier 40 Sensor control circuit 51-56 Servo motor

Claims (8)

[Claims] 1. A robot deburring control method for deburring a workpiece by a robot, comprising: a deburring tool attached to an arm of the robot; and an overload detection for detecting an overload on the deburring tool. Means, movement command means for issuing a movement command for each axis of the robot according to a machining program, axis control means for driving each axis of the robot according to the movement command to operate the deburring tool, and the overload detection A deburring control method for a robot, comprising: a forced stop control means for forcibly stopping the operation of the deburring tool with respect to the axis control means when an overload is detected by the means. 2. A deburring control method for a robot for deburring a work by a robot, comprising: a deburring tool attached to an arm of the robot; and overload detection for detecting an overload on the deburring tool. Means, movement command means for issuing a movement command for each axis of the robot according to a machining program, axis control means for driving each axis of the robot according to the movement command to operate the deburring tool, and the overload detection Deburring control means for retracting the deburring tool in a direction to reduce the overload when the overload is detected by the means. . 3. The deburring control of the robot according to claim 2, wherein the retraction control means is configured to retract the deburring tool in a retreat direction preset in a tool coordinate system. method. 4. The deburring control system for a robot according to claim 2, wherein the retraction control means is configured to retract the deburring tool in a direction opposite to a traveling direction. 5. A robot deburring control method for deburring a work by a robot, comprising: a deburring tool attached to an arm of the robot; and overload detection for detecting an overload on the deburring tool. Means, movement command means for issuing a movement command for each axis of the robot according to a machining program, axis control means for driving each axis of the robot according to the movement command to operate the deburring tool, and the overload detection A deburring control means for reducing the gain of at least one axis of the robot to reduce the rigidity of the axis when an overload is detected by the means. 6. A deburring control method for a robot for deburring a workpiece by a robot, comprising: a deburring tool attached to an arm of the robot; and overload detection for detecting an overload on the deburring tool. Means, movement command means for issuing a movement command for each axis of the robot according to a machining program, axis control means for driving each axis of the robot according to the movement command to operate the deburring tool, and the overload detection When an overload is detected by the means, a retreat control means for retracting the deburring tool with respect to the axis control means, and a deburring tool retracted by a predetermined retreating distance, the deburring toward the workpiece. The retry control means for retrying the tool, the retry and the retreat are repeated, and the deburring operation is set in advance. When carried out up to the cycle end position,
A retry cycle control means for returning the deburring tool to the deburring start position side and repeating the deburring operation by the retry control until a preset deburring stop condition is reached, and when the deburring tool returns, And an execution position control means for returning the deburring tool to a position near the deburring operation start point by a predetermined amount from the point where the overload is first detected in the cycle, and executing the retry from the returned position. A deburring control method for robots, which is characterized in that 7. A deburring control method for a robot for deburring a work by a robot, comprising: a deburring tool attached to an arm of the robot; and overload detection for detecting an overload on the deburring tool. Means, movement command means for issuing a movement command for each axis of the robot according to a machining program, axis control means for driving each axis of the robot according to the movement command to operate the deburring tool, and the overload detection When an overload is detected by the means, a retreat control means for retracting the deburring tool with respect to the axis control means, and a deburring tool retracted by a predetermined retreating distance, the deburring toward the workpiece. The retry control means for retrying the tool, the retry and the retreat are repeated, and the deburring operation is set in advance. When carried out up to the cycle end position,
Retry cycle control means for returning the deburring tool to the deburring start position side and repeating the deburring operation by the retry control until a preset deburring stop condition, and the number of retries in one cycle. A deburring control for a robot, comprising: a retry count storing means to be stored; and a speed changing control means for changing the moving speed of the deburring tool in the present cycle according to the retry count in the previous cycle. method. 8. The deburring control method for a robot according to claim 7, wherein the speed change control means is configured to increase the moving speed of the deburring tool as the number of retries decreases. .