JPH0790481B2 - Work transfer robot control method - Google Patents

Description

The present invention relates to a method for controlling a work transfer robot, and more specifically, to a predetermined transfer point by controlling the operation deceleration of the work transfer robot. The present invention relates to a method for controlling a work transfer robot that enables a work to be efficiently and accurately positioned at high speed without stopping the robot.

BACKGROUND OF THE INVENTION For example, after holding a workpiece manufactured by a press machine or the like by an air suction plate and moving to a predetermined line,
There is a work transfer robot that positions a work at a predetermined transfer point by releasing the holding state. In this case, the robot is required to shorten the cycle time as much as possible in order to improve the efficiency of work transfer work.

Therefore, as a method of shortening the cycle time, it is possible to operate the robot continuously and at high speed without stopping it. However, when the robot operates in this way, various problems occur.

That is, when the work holding state is released without stopping the operation of the robot, there is a wide range of work release timing due to the residual pressure of the suction cup, the wind pressure on the work, and the acceleration to the work, and the direction in which the work falls There is a possibility that the work may not be accurately positioned at a predetermined transfer point because the work is not fixed. Even when the trajectory of the work separated from the robot is predicted and the release point of the holding state is set in consideration of the above problems, the clamp state, the shape, etc. may be subtle due to the above factors. Therefore, the transfer position of the work may change, and the work may be deformed in some cases.

[Object of the Invention] The present invention has been made in order to overcome the above inconvenience, and after moving a robot holding a work to a vicinity of a transfer point at a predetermined deceleration, deceleration of the robot is performed. By changing the deceleration rate higher than the deceleration rate and releasing the holding state of the work piece at the same time, the work piece can be accurately positioned at a desired transfer point, and the transfer work can be performed efficiently. An object is to provide a method for controlling a work transfer robot.

[Means for Achieving the Object] In order to achieve the above object, the present invention continuously operates a work transfer robot having a work suction holding mechanism and having a variable deceleration for each teaching point. At the time of performing the work transfer work with the work, the work is held by the suction holding mechanism and is moved to a predetermined transfer position with a predetermined deceleration, and then the work is moved to a position close to the predetermined transfer position. When it arrives,
At the same time as increasing the predetermined deceleration, the holding state of the work by the suction holding mechanism is released to separate the work from the suction holding mechanism, and the work is moved in the speed vector direction at the time of the separation to predetermined the work. It is characterized by positioning at the transfer point.

[Embodiment] Next, a preferred embodiment of a method for controlling a work transfer robot according to the present invention will be given and described in detail below with reference to the accompanying drawings.

In FIGS. 1 and 2, reference numeral 10 indicates a work sorting device to which the work transfer robot control method according to the present invention is applied. This work sorting device 10 has a work transfer robot 14 supported by a frame 12, and a press device 16
The two types of works W ₁ and W ₂ manufactured by the above are separately sorted and transferred to the first conveyor 18 and the second conveyor 20. A pallet 22 in which the work W ₂ is stored is placed on the second conveyor 20.

The workpiece transfer robot 14 is composed of a three-axis control robot, and a main body 28 which can be moved in the arrow X direction by an X-axis motor 26 along a pair of guide rails 24a and 24b fixed to the frame 12.
A first arm 30 fixed to the main body 28 and extending vertically downward, and a Z-axis motor 32 having one end pivotally attached to the first arm 30.
The second arm 34 rotatable by the arrow Z direction and the other end of the second arm 34 are pivotally attached by the U-axis motor 36 to the arrow U
And a work suction-holding mechanism 38 that is rotatable in the direction. In this case, the work suction-holding mechanism 38 has two pairs of beams 40a, 40b extending in both directions and oriented in a direction orthogonal to the arrow X direction.
And 42a, 42b are attached. And these beams
40a, 40b and 42a, 42b are equipped with suction plates 44a to 44d and 46a to 46d for suction-holding the works W ₁ and W ₂ by a pneumatic mechanism (not shown).

On the other hand, there is an arrow X between the press device 16 and the first conveyor 18.
The guide rails 48a and 48b extending in the direction are provided. The guide rails 48a and 48b carry the works W ₁ and W ₂ mounted thereon and are movable in the arrow X direction by a drive mechanism (not shown). The table 50 is mounted.

Here, the control mechanism of the work transfer robot 14 is configured as shown in FIG. That is, this control mechanism includes a master operation panel 52 including a sequencer, a robot controller 54 for controlling the operation of the work transfer robot 14, and a teaching box 56 for teaching the work transfer robot 14. In this case, teaching box 56
With, it is possible to set the speed, acceleration, and deceleration for each teaching point, and to set an instruction for driving a solenoid or the like, which will be described later, at each teaching point. Robot controller
54 is each motor 26, 32, which constitutes the workpiece transfer robot 14,
36 drive control, operation control of a mechanical brake 58 for stopping the drive of these motors 26, 32, 36, and suction plates 44a to 44
The operation control of the solenoid 60 that controls the suction action of the works W ₁ and W ₂ by d, 46a to 46d is performed. In addition, each motor 26,
The operation of the workpiece transfer robot 14 by 32 and 36 is detected by the absolute encoder 62 and fed back to the robot controller 54.

The work sorting device to which the method of controlling a work transfer robot according to the present embodiment is basically configured as described above.
Flow chart shown in the figure and each motor 2 shown in FIG.
Description will be made based on the operating states of 6, 32, and 36.

First, the works W ₁ and W ₂ manufactured by the pressing device 16 are set on the transfer table 50 located at the backward end A (see FIG. 2) by a transfer device (not shown) (STP1). Then
The carriage 50 moves in the direction of arrow X along the guide rails 48a and 48b under the action of a drive mechanism (not shown), and then reaches the forward end B on the first conveyor 18 (STP2).

Next, the master operation panel 52 outputs a start command to the robot controller 54. In this case, the work suction holding mechanism 38 of the work transfer robot 14 is on standby at the pattern origin C. Therefore, the robot controller 54 operates the X-axis motor 26, the Z-axis motor 32 and the U-axis based on the start command.
The shaft motors 36 are each rotated in the negative direction at the rate shown in FIG. The work suction-holding mechanism 38 moves from the pattern origin C toward the forward end B and moves to the suction plates 44a to 44d and 46.
The a to 46d come into contact with the works W ₁ and W ₂ on the carrier 50. Then, the robot controller 54 uses the solenoid 60.
Outputs a drive signal to the workpiece W _1, W ₂ under the action of pneumatic mechanism (not shown) each suction cup 44a to 44d, are adsorbed to 46a to 46d (STP3). Then, the robot controller 54
Causes each of the motors 26, 32 and 36 to rotate in the plus direction to quickly return the work suction-holding mechanism 38 to the pattern origin C.

On the other hand, the transfer table 50 in the empty state moves under the action of a drive mechanism (not shown) along the guide rails 48a and 48b to the retreat end A, and then receives the next works W ₁ and W ₂ from the press device 16. Will be in the standby state (STP4).

The robot controller 54 again operates on each motor 26, 32 and 36.
To the pattern origin C with the work suction-holding mechanism 38 sucking the works W ₁ and W _2.
With a predetermined acceleration, the speed gradually increases while descending (STP
Five). Next, at the point where the work suction holding mechanism 38 descends by a predetermined amount, the robot controller 54 causes the motors 26, 32 and
36 is switched to the deceleration operation and the descending operation is continued at a predetermined deceleration. Then, when the work suction-holding mechanism 38 reaches the point d close to the lower end D (see FIG. 6), the robot controller 54 outputs a drive signal for deceleration to each of the motors 26, 32 and 36 again. . Therefore, the work suction-holding mechanism 38 increases its deceleration in the vicinity of the lower end D (STP6). At this time, the robot controller 54 further outputs a drive signal to the solenoid 60, and the suction plate 44a
The adsorption of the work W ₁ by the to 44d is released (STP7).

In this case, the work W ₁ continues to descend to the first conveyor 18 side at the speed immediately before the suction action by the suction plates 44a to 44d is released, while the work suction holding mechanism 38 increases the deceleration faster than immediately before. It descends toward the descending end D at a speed. Here, if the deceleration is not increased at the point d near the descending end D, the work W ₁ is sucked by the suction disc even after the suction action is released.
It is dragged by 44a to 44d, which causes the work W ₁ to descend in the direction of arrow a in FIG. On the other hand, when the deceleration of the work suction holding mechanism 38 is increased at the point d, the work W ₁ and the work suction holding mechanism are
The workpiece W ₁ is forcibly separated from the workpiece 38 due to the difference in deceleration, and the workpiece W ₁ descends in the direction of arrow b, which is the tangential direction of the moving direction of the workpiece suction holding mechanism 38 when the suction is released. As a result, the work W ₁ is accurately positioned at a predetermined transfer position on the first conveyor 18 without being affected by the next operation of the work suction holding mechanism 38 (STP8). Then, the work W ₁ placed on the first conveyor 18 is conveyed to a predetermined work station (STP9).

On the other hand, the work suction-holding mechanism 38 that has separated the work W ₁ toward the first conveyor 18 speeds up again based on the drive signal from the robot controller 54 (STP10) without stopping its operation, and each motor 26, Under the driving action of 32 and 36, the front end F is passed through the front end B, the pattern origin C, and the ascending end E.
Move to (STP11). Then, only the Z-axis motor 32 is rotated in the negative direction, is directed to the pallet 22 placed on the second conveyor 20, moves to the descending end G, and stops.
Next, the robot controller 54 outputs a drive signal to the solenoid 60, whereby the suction action of the work W ₂ by the suction plates 46a to 46d is released (STP12). In this case, the work W ₂ is transferred into the pallet 22 (STP13) and conveyed to the predetermined work station by the second conveyor 20 (STP14).

On the other hand, the work transfer robot 14 in which the work W ₂ is separated from the work suction holding mechanism 38 returns to the pattern origin C again,
Wait for work to transfer the next work W ₁ and W ₂ (ST
P15).

[Effects of the Invention] As described above, according to the present invention, after the work is held by the work holding means, the work is moved to the vicinity of a predetermined point at a predetermined deceleration, and then the deceleration is increased and the work holding state is maintained. By releasing the above, the work is promptly transferred to the predetermined point without stopping the robot. In this case, by increasing the deceleration, the work and the work holding means can be reliably separated, and the work moves in the direction of the speed vector at the time of separation without being influenced by the movement direction of the work holding means, It will be transferred to a predetermined location accurately. Further, since the operation of the work holding means does not affect the work released from the held state, the work holding means can be quickly moved to the next work point, thereby shortening the cycle time. However, it is possible to improve work efficiency.

Although the present invention has been described with reference to the preferred embodiment, the present invention is not limited to this embodiment,
It goes without saying that various improvements and design changes can be made without departing from the scope of the present invention.

[Brief description of drawings]

FIG. 1 is a perspective view of the configuration of a work sorting apparatus to which the method for controlling a work transfer robot according to the present invention is applied, FIG. 2 is an operation explanatory view of the work sorting apparatus shown in FIG. 1, and FIG. FIG. 4 is a schematic block diagram of the control mechanism of the work transfer robot shown in FIG. 4, FIG. 4 is a flowchart showing the operation procedure of the work sorting apparatus shown in FIG. 1, and FIG. 5 is a drive system for the work transfer robot shown in FIG. 6 is an explanatory view of the locus of the robot and the locus of the work at the departure point of the work. 10 …… Work sorting device, 12 …… Frame 14 …… Work transfer robot, 16 …… Press device 18, 20 …… Conveyor, 26, 32, 36 …… Motor 38 …… Work suction holding mechanism 44a to 44d , 46a-46d …… Suction board 50 …… Transportation platform

 ─────────────────────────────────────────────────── ─── Continuation of front page (72) Inventor Kuniichi Negishi 1-10-1 Shin-Sayama, Sayama-shi, Saitama Honda Engineering Co., Ltd. (56) References: 63-107584 (JP, U)

Claims (1)

[Claims] 1. When performing a work transfer work by continuously operating a work transfer robot having a work suction and hold mechanism and a deceleration variable for each teaching point, the work is held by the suction and hold mechanism. In the state of holding, it moves toward a predetermined transfer position at a predetermined deceleration, and then, when the work reaches a point close to the predetermined transfer point,
At the same time as increasing the predetermined deceleration, the holding state of the work by the suction holding mechanism is released to separate the work from the suction holding mechanism, and the work is moved in the speed vector direction at the time of the separation to predetermined the work. A method for controlling a work transfer robot, which is characterized by positioning at a transfer point.