JPH0233454B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a conveyance device having a plurality of conveyance axes, and particularly to a positioning means thereof.

An example of a transfer device having a plurality of transfer shafts is a transfer device of a transfer press machine. For example, in the case of a three-dimensional system, this transfer device includes transfer bars 1 and 1 shown in FIG.
are clamped in the X-axis direction so as to bring them close to each other, and a material to be pressed (not shown), which is a conveyed object, is held between the fingers 2 provided on these transfer bars, and then lifted in the Z-axis direction. After that, it is operated in advance in the Y-axis direction, further in the down-movement in the Z-axis direction, and then unclamped in the X-axis direction to release the pressed material held by the fingers 2, and then returned in the Y-axis direction. A series of conveyance operations is performed in synchronization with the operation of the press machine.

By the way, the conveying means that conveys and positions the conveyed object along the bent path as described above inevitably has a long conveying path.

Therefore, in order to shorten the cycle time of conveyance, it is considered to start the conveyance means in two or three conveyance axis directions at the same time, but this causes the following inconvenience.

In other words, when transporting an object from point A to point B shown in Figure 2, if the transport means is moved simultaneously in the directions of two transport axes, the speed in the direction of each transport axis changes each time the speed in the direction of each transport axis changes. As exemplified in , different routes P, Q, and R are taken. Therefore, depending on the conveying route, a problem arises in that the conveying means comes into contact with other members of the conveying device.

An object of the present invention is to provide a conveying device for a transfer press machine that can shorten the conveyance cycle time as much as possible without causing the above-mentioned disadvantages.

Therefore, in the present invention, in a conveyance device having at least two conveyance axes sequentially driven by different positioning servo systems, means for giving a target position command to the servo system for the conveyance axis driven first; means for instructing a refraction point position a predetermined distance before the target position based on the target position command as a positional deviation between the target position and the refraction point position; means for detecting that the positional deviation matches the commanded positional deviation; and means for giving a target position command to a servo system for a conveyance axis to be driven later when the positional deviation matches the positional deviation. is provided.

Hereinafter, the present invention will be explained in detail with reference to the illustrated embodiments.

FIG. 3 shows an embodiment of the present invention applied to a transfer device of a three-dimensional transfer press machine.

The motors M _X , M _Y and M _Z shown in the figure are the first
The transfer bars 1, 1 shown in the figure are operated in the X-axis, Y-axis, and Z-axis directions, and these motors are operated by motor drive circuits 4, 5, and 6 that receive command signals from a control command circuit 3. Driven.

The motor drive circuit 4 includes a counter 41 that counts output pulses from a pulse generator (for example, a pulse encoder) 40 that is interlocked with the motor _M and the _latch contents of the latch circuit 42.
The amplifier 45 inputs the deviation ε _X converted by the converter 44 to drive the motor M _X.

Note that the amplifier 45 is fed back with an output signal of a speed generator 46 that is interlocked with the motor _MX .

The other motor drive circuits 5 and 6 are the drive circuit 4
Since the structure is exactly the same as that of , the explanation thereof will be omitted.

The control command circuit 3 includes these drive circuits 4,
5 and 6 are controlled as follows. That is, first, a position command signal to move the transfer bar 1 shown in FIG. 1 from the point P ₀ shown in FIG. 4 to the point P ₁ shown in FIG.
S ₄ a, the distance between P′ ₁ (hereinafter referred to as the bending contact point) _, which is a predetermined distance closer to the P ₀ point than the P 1 point, and the P ₁ point (P ₁ = P ₁ )
Therefore, here, the signal S ₄ c indicating 0) and the signal S ₄ d specifying the X axis are applied to the latch circuit 42, the comparison circuit 48, and the AND circuit 49 at the timing shown in FIG. The signal S ₄ b is output to cause the latch circuit 42 to latch the signal S ₄ a.

As a result, the position command signal Sa is
3, thereby causing the transfer bar 1 to start moving from the P ₀ point to the P ₁ point.

While the motor _M
Specify the position command signal S ₆ a for P ₁ to _{P 2} , the signal S ₆ c indicating the distance P' ₂ to P ₂ from the refraction point P' ₂ shown in Fig. 4, and the Z axis _. On the other hand, the comparator circuit 48 outputs the signal S ₆ d between the deviation _ε
Compare S ₄ c (P ₁ to P′ ₁ =0).

The _comparator 48 outputs a signal when the _{deviation ε} OR circuit 47,
57 and 67 to the latch signal input terminals of latch circuits 42, 52 and 62.

At this time, since the position command signal S ₆ a is generally given to the latch circuit 62, the motor M _Z operates at the same time as the latch signal S ₄ e is input.
This moves the transfer bar from point _P1 toward point _P2 .

Therefore, before the transfer bar is moved from point _P1 to point _P'2 , a position command signal in the advance direction _P2 to _P3 is sent at the timing shown in Figure 5a.
S ₅ a, a signal suggesting the distance P′ ₃ ~ _{P 3} shown in Fig. 4
A signal S ₅ c and a signal S ₅ a specifying the Y axis are outputted from the control command circuit 3, and a signal is outputted from the comparison circuit 68 when the transfer bar reaches the bending contact point _P'2 . The output signal of the comparator circuit 68 causes the AND circuit 60 to output S ₆ e, and this signal generally causes the position command signal S ₅ a applied to the latch circuit 52 to be latched in this circuit, so that the motor M _Y is will be activated.

Since the motor M _Z is still operating at this point, the motor M Z remains active for the period T ₁ shown in FIG. 5d.
M _Y is actuated simultaneously, and as a result, the transfer bar is moved in a manner that passes through area A shown by diagonal lines.

Thereafter, the control signal is outputted from the control command circuit at the timing shown in FIG. _5a , and the latch signal is sequentially outputted in the manner shown in _FIG . _Z is also the point of refraction
From P _{5 '} , motor _M

In the above embodiment, the transfer bar is not moved in two axes simultaneously in the transition from clamp operation to lift operation and the transition from down operation to unclamp operation, but this ensures reliable clamping and unclamping operations. It is for the purpose of doing. Of course, it is also possible to simultaneously move two axes at the _four points P ₁ and P. In such a case, the signals S ₄ c and S ₆ c shown in FIG. 3 should be set to predetermined finite values during return and advance operations. You can set it to . Furthermore, the widths of the above areas A, B and C are
It is changed by changing the positions of the refraction points P′ ₂ , P′ ₃ , and P′ _5. On the other hand, the movement locus of the transfer bar within each of the above regions changes depending on the movement speed in each axial direction. be done. Note that each output signal of the circuit 3 is output in synchronization with the operating angle θ of the press.

As described above, in the method according to the present invention, the conveyance means is simultaneously operated in two axes only at the conveyance direction switching section, so that the cycle time for conveyance positioning can be reduced without bringing the conveyance means into contact with other objects. Can be shortened.

Further, in the present invention, the refraction point position is specified as a positional deviation between the target position and the refraction point position, and when the actual positional deviation of the moving body matches the specified positional deviation, the conveyance shaft that is subsequently driven A target position command is given to the servo system.

Since the servo system for each conveyance axis is provided with a means for detecting positional deviation, the present invention, which determines the bending point position based on the positional deviation, utilizes the functions of the conventional servo system. The position of the refraction point can be easily detected.

Further, according to the present invention, since the refraction point can be changed, it is possible to easily set the refraction point that is optimal for the dynamic characteristics of the transport mechanism.

Of course, the present invention can be effectively applied not only to the transfer device of a press machine but also to other transfer devices, such as the positioning of a robot arm. It can also be applied to a conveyance device having a two-dimensional conveyance axis.

[Brief explanation of drawings]

Fig. 1 is a perspective view conceptually showing the operation mode of the transfer bar of the transfer press machine, and Fig. 2 is the movement of the transfer means when the transfer means are simultaneously operated in each axis direction in a two-dimensional transfer device. FIG. 3 is a block diagram showing an example of a control circuit of a transfer press machine to which the present invention is applied; FIG. 4 is a diagram showing a transfer bar of a three-dimensional transfer press machine operated according to the present invention. Figures 5a to 5e are diagrams illustrating the operating trajectory when the
3 is a timing chart showing the operation of the circuit shown in the figure. 1... Transfer bar, 3... Control command circuit, 4, 5, 6... Motor drive circuit, M _X , M _Y ,
_MZ ...Motor.

Claims (1)

[Claims] 1. In a conveyance device having at least two conveyance axes sequentially driven by different positioning servo systems, means for giving a target position command to the servo system for the conveyance axis driven first. and means for instructing a refraction point position a predetermined distance before the target position based on the target position command as a positional deviation between the target position and the refraction point position; means for detecting that the actual positional deviation matches the instructed positional deviation; and when the coincidence of the positional deviations is detected, giving a target position command to the servo system for the transport axis that will be driven later; A transfer device for a transfer press machine, comprising means.