JPH06206137A - Loader controller - Google Patents

Abstract

PURPOSE:To automate the instruction for a gravity shaft with a high precision, as for a gantry loader, etc. CONSTITUTION:A gravity shaft skip shifting means 24b and a gravity shaft instruction position determining means 25b are installed. The gravity shaft skip shifting means 24b lowers a loader chuck 6 holding a work W through applying a torque limit in an automatic instruction process, and presses the loader chuck 6 onto the upper surface of a fixed article 3. At this time, the load electric current of a Y shaft servomotor 31 as gravity shaft flows always by a constant electric current value I so that the loader chuck 6 and the work W do not drop, and when the electric current collides with the fixed article 3, the electric current value gradually lowers to zero. If time lapses in this state, electric current starts to increase. Accordingly, at the position where the motor electric current I becomes zero, the loader chuck is placed on the fixed article 3. The gravity shaft instruction position determining means 25b monitors the reduction of the motor electric current, and when a set reduction value (e.g. zero value) I0 is realized, the coordinate values of the Y shaft position detector 31 is read out. The instruction position is determined, setting the read- out value as standard.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a loader control device such as a gantry loader in a machine tool such as a lathe, and more particularly to a teaching structure thereof.

[0002]

2. Description of the Related Art In a gantry loader, one end of a work is gripped by a loader chuck to carry the work between a work supply table and a spindle chuck. When the length of the work is different, it is necessary to change the receiving / delivering position of the loader chuck by the work supply table or the spindle chuck. Therefore, conventionally, the receiving / delivering position of the loader chuck is taught each time the lot is changed to a lot having a different work length. This teaching is given, for example, by operating the loader in the manual mode.

However, the teaching operation by the operation in the manual mode is complicated and troublesome, and the teaching requires a long time.

Therefore, the present applicant has considered a method of automatically determining a teaching point by detecting the load of the loader. That is, as shown in FIG. 12A, the loader chuck 71 holding the work W is horizontally skipped to move the spindle chuck 7
This is a method in which the axis feed is stopped and the coordinate position is determined as the teaching position when the load is pressed against No. 2 and the load rises to the set level. As shown in FIG. 7B, with respect to the work feeder 73, the loader chuck 71 is moved down and the teaching position is determined by load detection in the same manner as described above. As a load detecting method, a method of monitoring a current is adopted, which is generally adopted as a load detecting method of a servo motor.
That is, it is determined that the load increases as the current increases.

[0005]

Although the teaching position can be determined by the load detection when the feed axis is the horizontal axis Z as shown in FIG. 12 (A), it can be determined well as shown in FIG. 12 (B). When the gravity axis (vertical axis) Y is large, it cannot be accurately performed. That is, in the case of the horizontal axis Z, the work W is the main shaft chuck 72.
The relationship between the load after being pressed against and the motor load current has a proportional relationship as shown in FIG. Therefore, it is possible to determine that the predetermined load T _H has acted by appropriately setting the contact determination current value I _A. However, in the case of the gravity axis Y as shown in FIG.
A constant holding current is constantly flowing so that the loader chuck 71 and the work W do not drop, and when hitting the work feeder 73, the current decreases for a predetermined time as shown in FIG. 13B. In this state, when the time further elapses, the current starts to increase, and when the contact determination current value I _A is reached, it is determined that the work feeder 73 has been hit.

At this time, the load T _V applied to the work feeder 73 is the sum of the weight of the loader chuck 71 on the gravity axis Y and the load due to the current flowing until the load current of the servo motor is detected. , Which is a considerably large value. T _V > T _H. Therefore, it is impossible to detect the load on the gravity axis Y and determine the teaching position only by increasing the current, and accurate teaching cannot be performed.

An object of the present invention is to provide a loader control device capable of automatically teaching a gravity axis with high accuracy.

[0008]

The structure of the present invention will be described with reference to FIG. 8 corresponding to the embodiment. This loader control device is provided with a gravity axis skip moving means (24b) and a gravity axis teaching position determining means (25b). The gravity axis skip moving means (24b) is means for lowering the loader chuck (6) holding the work (W) in the automatic teaching process and pressing it against the upper surface of the fixed object (3). The gravity axis teaching position determining means (25b) monitors the load current (I) of the motor (31) of the ascending / descending feed shaft (Y) of the loader chuck (6) during the skip movement, and the current value is the set decrease value. It is a means for reading the coordinate value of the feed axis (Y) when it decreases to (I ₀ ), and determining the teaching position based on this read value.

[0009]

[Operation] Loader chuck (6) holding the work (W)
Is axially moved downward by a command from the gravity axis skip moving means (24b) and pressed against the fixed object (3) via the work (W). At this time, the load current (I) of the motor (31) of the ascending / descending feed shaft (Y), which is a gravity shaft, is constantly flowing so that the loader chuck (6) and the work (W) do not drop. When hitting the fixed object (3), the current value gradually decreases to zero. In this state, when the time further passes, the current starts to increase. That is, the position (H) where the motor current becomes zero is a state in which the loader chuck (6) is placed on the fixed object (3). The gravity axis teaching position determining means (25b) monitors the decrease in the motor current (I), and when the set decrease value (I ₀ ) becomes zero, for example, the coordinate value of the feed axis (Y) is set. read. The teaching position is determined based on this read value.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described with reference to FIGS. In FIG. 1, a loader 1 is of a gantry type, and is movably installed on a rail 4 installed between a lathe 2 and a work feeder 3. Loader 1
Is provided with a pair of loader chucks 6 at the lower end of the elevating rod 5 so as to be reversible with each other. The loader chuck 6 moves along the rails 4 in the traveling axis (Z axis) direction and the gravity axis (Y
It is possible to move in the (axis) direction. The elevating drive is performed by the Y-axis servo motor 31 shown in FIG. 3 (and FIG. 8), and the traveling drive is performed by the Z-axis servo motor 32. Each of these servomotors 31 and 32 is composed of a DC motor, and each of them is provided with position detectors 35 and 36 such as a pulse coder and ammeters 33 and 34 for detecting a load current.

In FIG. 1, a lathe 2 is a spindle chuck 7
Is a turret lathe in which a turret 8 (FIG. 2) is installed on the lateral side of the machine, and has a ceiling opening 9 on the ceiling surface of the machine body cover through which the loader chuck 6 can move in and out. The work feeder 3
A pallet (not shown) on which the work W is placed is moved along a predetermined circulation path, and two points located below the traveling path of the loader 1 on the circulation path are set at the material loading position P.
3 and the processed product carry-out position P4.

In the loader 1, for example, the following operation is repeated. That is, the loader chuck 6 is moved to a predetermined entry position Q facing the spindle chuck 7, and the loader 1 is moved to the spindle chuck 7 side from here, so that the work W gripped by the spindle chuck 7 is moved to one of the loaders. Unload with chuck 6. Then, it is retracted to the approach position Q. Here, the positions of the two loader chucks 6 are switched by a reversing operation, the loader 1 is again moved to the spindle chuck 7 side, and the material work W grasped in advance is loaded on the spindle chuck 7. After that, the loader 1 is retracted to the entry position Q, the loader chuck 6 is ejected above the lathe 2, and then the loader chuck 6 is moved to above the finished product unloading position P4. Then, the loader chuck 6 holding the workpiece W is lowered and the finished workpiece W is unloaded onto the workpiece feeder 3.

After that, the loader chuck 6 is raised, the material carrying-in position P3 is moved upward, and the loader chuck 6 is lowered, so that the loader chuck 6 grips a new material work W on the work feeder 3. Then, the loader chuck 6 rises, the loader 1 travels above the approach position Q, and waits for the completion of machining by the lathe 2. When the processing is completed, the loader chuck 6 is lowered to the entry position Q and the above operation is repeated. In the case of a model having only one loader chuck 6, after unloading, the loader chuck 6 is moved to the finished product unloading position P4 to discharge the finished product work W, and thereafter, the material work W is carried in and loaded sequentially.

When performing such repetitive operation,
When the type of work W is changed, there are loader coordinate values that need to be changed and coordinate values that do not need to be changed depending on the work length. That is, coordinate values that do not need to be changed are
The Z coordinate of the material loading position P3 and the workpiece unloading position P4, both Y and Z coordinates of the entry position Q, and the loading position P
2 and Y coordinates of the unloading position P1. The coordinate values that need to be changed are the Z coordinate of the loading position P2 and the unloading position P1, and the material loading position P.
3 and the Y-coordinate of the processed product unloading position P4.

The loader control device of this embodiment is designed to automatically teach the coordinate values at the four positions that change depending on the work length, and the Y coordinate of the material carry-in position P3 and the workpiece carry-out position P4 of these coordinate values. The present invention is applied to automatic teaching as described below. Each coordinate value that does not change depending on the workpiece length is set when the machine is installed and operated as a fixed value.

FIG. 3 is a conceptual diagram of the loader control device. The loader control device 10 is an NC control device including a CPU, a memory device, and the like, and has a function of interactively setting each data and the like using an operation panel 12 having a display device 11 such as a CRT. The data memory 13, the basic loader control means 21, the mode-based operation control means 16, and the work-based loader control program storage means 17 are the main functional means constituting the loader control device 10. The basic loader control means 21 comprises an overall operation control means 14 and a partial operation control means 15.

The data memory 13 has a mode selection means 1
8, various data setting area 20, teaching data storage area 1
9 and 9 are provided. The various data setting area 20 is a storage area for setting various setting values other than the teaching data by operating the operation panel 12 or the like. The mode selection means 18 is a storage area for a mode setting flag, and can selectively set the A mode and the B mode as basic modes. In A mode, the operation mode, teaching mode,
Three modes are selectable, and an automatic mode. B
In the mode, interactive automatic edit mode, non-interactive automatic edit mode, and invalid mode can be selected as operation modes.

In the A mode, the control of the loader 1 depends on one of the basic loader control programs 41, as will be described later in detail, and the teaching position is changed each time the work is changed. And respond. In other words, it is a mode mainly based on the teaching position. The B mode is a mode in which a loader control program for each work W is created based on the basic loader control program 41, and is a program-based mode.

The basic loader control means 21 is a control means for executing the basic loader control program 41. The basic loader control program 41 is composed of a main program 40 in which an overall operation for teaching and driving is described as will be described later with FIG. 4, and a teaching macro program 37 called by the main program 40. The means for executing the main program 40 is the overall operation control means 14, and the means for executing the teaching macro program 37 is the partial operation control means 15.

The partial motion control means 15 has a driving time control means 22 and a teaching time control means 23, and a teaching operation for one location and a driving operation control command corresponding to teaching data are set. The teaching time control means 23 is configured to skip the movement means 24.
And teaching position determining means 25. The skip moving means 24 is a means for monitoring the torque acting on the Y-axis servo motor 31 and the Z-axis servo motor 32 with the current values of the ammeters 33 and 34, and performing low speed feeding while applying the torque limit. Horizontal axis skip moving means 24 for axis
a (FIG. 8) and vertical axis skip moving means 24b for the Y axis. The teaching position determining means 25 is also composed of a horizontal axis teaching position determining means 25a for the Z axis and a gravity axis teaching position determining means 25b for the Y axis. Each teaching position determination means 25a,
25b includes the control programs of FIGS. 6 and 9 which will be described later.

In FIG. 3, mode-specific operation control means 16
Is composed of an A mode control means 26 and a B mode control means 27 which respectively perform dedicated control in the A mode and the B mode.
The A mode control means 26 has a standard coordinate value automatic setting means 28, and the B mode control means 27 has an automatic editing means 29. Work loader control program storage means 17
Is a memory area for storing each work loader control program 30 created in the B mode. The detailed functions of the respective means will be supplemented later in the description of the operation.

FIG. 4 shows the program structure of the basic loader control program 41. Basic loader control program 41
Is commonly used for A mode and B mode during teaching,
In addition, there is a program used in the operation mode in the A mode. In the main program 40 of the basic loader control program 41, a calling command G100, a stop command M120, and a replacement command M77 for the teaching macro program 37 are described for each teaching point, and in addition to the operation performed by the teaching macro program 37. A command for each operation required during operation, such as a move command T1 to the first teaching motion start position, is described. The stop command M120 and the replacement command M77 are commands that have no effect in the A mode. In the teaching macro call command G100, arguments Z1, Z2, Y3 and Y4 indicating teaching positions are set. The arguments Z1 and Z2 correspond to the Z coordinates of the unloading position P1 and the loading position P2, respectively, and the arguments Y4 and Y4 correspond to the Y coordinates of the material loading position P3 and the workpiece unloading position P4, respectively. At the end of the program, the tape end processing command M
Before 30, the flag setting command T2 for performing a predetermined automatic flag setting is described.

The teaching macro program 37 comprises an operating section and a teaching section. The operation section is a program section for performing axis movement based on the teaching data when not in the teaching mode in the A mode, and determines where to move based on an argument. That is, the feed position of the axis feed command R2 is set as a variable according to the argument. The teaching portion is a program portion for performing a teaching operation, and determines which position is taught by an argument and which of the horizontal axis teaching position determining means 25a and the gravity axis teaching position determining means 25b is used.

The operation of the above configuration will be described. In automatic teaching, the teaching screen is called on the display device 11 of the operation panel 12 to select a mode, the material work W is set on the work feeder 3 and the finished work W is set on the spindle chuck 7, and the start button is pressed. As a result, the teaching is performed automatically thereafter.

5 and 6 show the operation during automatic teaching in the case of the horizontal axis (Z). This operation is common to A mode and B mode. This figure shows the operation at the loading position P2 (FIG. 1). The start position is a coordinate position at the time of calling the macro and is, for example, the approach position Q in FIG. The axis is moved rapidly from the start position to the set value (step S1 in FIG. 6), and then the skip movement is started. As a result, when the work W is pressed against the spindle chuck 7, the load current of the Z-axis servomotor 32 increases. During the skip movement, this load current value is monitored (S
3) When the limit value is reached, the axis is stopped (S4). The coordinate value at the time of stop is read, and the value corrected by the correction amount Δs is determined as the coordinate value of the teaching position (S5). This determined value is stored in a predetermined address (address corresponding to the argument) in the teaching determined value storage area 19 (S6).

Even when the load current does not reach the limit value,
When it reaches the position of (set value) + (predetermined skip movement amount) (S7), the axis feed is stopped (S8). in this case,
Although NG is displayed on the screen (S9), the stop position is stored in the teaching determination value storage area 19 as the determination value. When the teaching operation is completed, the teaching program automatically moves to the next teaching start position according to the main program 40.

It should be noted that approximate coordinate values are arbitrarily set in advance as the set values. The skip movement amount and the correction amount Δs are also set appropriately. The correction value Δs indicates the offset amount with respect to the skip coordinate value. That is, the data for correcting the slippage of the loader chuck 6 and the mechanical deflection amount at the time of pressing is set. The correction amount Δs may be set after the teaching position is fixed, and the determined value may be changed in conjunction with this value. These set values, skip movement amount,
The standard coordinate value automatic setting means 28 allows the correction amount Δs to be automatically set according to the data registered in advance, only by designating the model data.

8 and 9 show the teaching operation in the case of the gravity axis (Y axis), that is, the teaching operation of the Y-axis coordinate of the finished product carry-out position P4 or the material carry-in position P3. Similar to the case of the horizontal axis, the axis is moved rapidly from the start position to the set value (step U1 in FIG. 9), and then the skip movement is started (U2). During this movement, the Y-axis servo motor 31
A negative torque acts to prevent the loader chuck 6 from falling, and a negative holding current flows as a load current. When the work W hits the upper surface of the work feeder 3, the load gradually decreases and the holding current approaches zero. The position H where the holding current becomes zero is a state in which the loader chuck 6 is placed on the work feeder 3 via the work W, and this position H is determined as the coordinate value of the taught position (U5). In addition, from the position H, the correction calculation (U4) is performed as in the case of the horizontal axis.
Alternatively, the coordinates of the teaching position may be determined.

After the loader chuck 6 is placed on the work feeder 3, the axial feed is continued. Therefore, the loader chuck 6 is pressed against the work feeder 3 and the load current of the Y-axis servo motor 31 is in the positive direction. Gradually increase. When this limit is reached by this increase (U
6) Stop the axis feed (U7). During this stop, the torque limit current continues to flow. When a predetermined stop time elapses, the loader chuck 6 rises, reaches the origin of rise, and stops. Even if the load current does not reach the limit value, when the position reaches (set value) + (predetermined skip movement amount), (U
8) Stop the axis feed (U9). In this case, NG is displayed on the screen or the like (U10), but the stop position is stored in the teaching determination value storage area 19 as the determination value. Such automatic teaching according to the horizontal axis and the gravity axis is sequentially performed at each of the four teaching positions. In this embodiment, teaching is performed in the order of the unloading position P1, the loading position P2, the finished product unloading position P4, and the material loading position P3.

10 and 11 show the operation after automatic teaching in the case of the horizontal axis in the A mode. When the coordinates are determined by automatic teaching, the operation mode is set. In the operation mode, the operation part of the teaching macro program 37 controls the
That is, by the control of the driving control means 22 in FIG. 3, fast-forwarding is performed to the front by the predetermined distance a of the determined coordinates (FIG.
Step R1) of the above, from there to the determined coordinates are sent at low speed. The predetermined distance a is set to an appropriate value, for example, a value of about 10 mm.

In each operation mode selectable in the A mode, the following operation is performed. In the teaching mode, the operation ends when all teaching positions are determined by executing one cycle of the main program 40. It is also possible to make repeat operation in this mode. In the operation mode, it operates according to the coordinates determined in the teaching mode. In the automatic mode, operate the first cycle started in the teaching mode,
From the next cycle, the operation mode is automatically entered. The switching to the automatic operation is performed by the mode change flag setting command T2 set at the end of the main program 40 functioning in the automatic mode to set the flag.

The operation after automatic teaching in the B mode will be described. In the B mode, based on the main program 40 of the basic loader control program 41, a new work-specific loader control program 3 is created by the automatic editing means 29 as follows.
0 is created. That is, when automatic teaching is performed, the replacement instruction M77 prepared in the main program 40 is prepared.
Is replaced by the axis feed command (Y--) as shown in FIG. 7 (B). The value determined by the above-described automatic teaching is written in the coordinate value of this axis feed command. In this way, each replacement command M77 is replaced with the axis feed command, and the completed loader control program 30 is registered in the work-specific loader control program storage means 17.

In each operation mode selectable in the B mode,
The following actions take place: In the interactive automatic edit mode, when the teaching operation ends at each teaching position, the editing operation is automatically performed, and after the teaching position is written in the program, the teaching operation is stopped on the spot under the control of the stop command M120. The non-interactive automatic editing mode is basically the same as the interactive automatic editing mode, but it does not stop at the teaching position. After the program is edited, it starts automatically.

The invalid mode is a mode for invalidating the teaching operation by the basic loader control program 41. This mode is set after the program is created in the interactive automatic editing mode or the non-interactive automatic editing mode. As a result, the loader control program 30 created in the B mode can be executed. If the mode change flag setting command T2 is included in the basic loader control program 41, the invalid mode is automatically set after one cycle of operation in the automatic edit mode.

According to this loader control device, automatic teaching can be performed in this manner, operation is simple, and teaching can be performed quickly. When teaching the gravity axis, the loader chuck 6
Since the teaching position is determined by detecting the change in the motor current that decreases due to the load on the work feeder 3, position teaching can be performed accurately regardless of gravity acting on the loader chuck 6 and the like. Although the above embodiments have been described with respect to application to a gantry loader, the present invention can be applied to teaching of a shaft on which gravity acts in various other types of loaders. Further, the present invention can be applied not only to the loader 1 attached to the lathe but also to loaders equipped in various machine tools.

[0036]

According to the loader control device of the present invention, the loader chuck holding the work is lowered by the skip movement and pressed against the upper surface of the fixed object, and the change in the motor current which is reduced by the loader chuck being mounted on the fixed object is detected. Since the teaching position is determined in this way, the teaching of the loader chuck position in the case of the gravity axis can be automatically performed with high accuracy.

[Brief description of drawings]

FIG. 1 is a front view of a loader and a lathe to which a loader control device according to an embodiment of the present invention is applied.

FIG. 2 is a plan view of the lathe.

FIG. 3 is a block diagram of a conceptual configuration of the same loader control device.

FIG. 4 is an explanatory diagram showing a program configuration of the basic loader control program.

FIG. 5 is an explanatory diagram of a teaching operation in the case of a horizontal axis.

FIG. 6 is a flowchart of the same teaching operation.

FIG. 7 is an explanatory diagram showing a program structure before and after teaching in the B mode.

FIG. 8 is an explanatory diagram showing a conceptual configuration of a main part of the same loader control device and a teaching operation of a gravity axis.

FIG. 9 is a flowchart of a gravity axis teaching operation.

FIG. 10 is an explanatory diagram of a driving operation corresponding to teaching data in the case of a horizontal axis.

FIG. 11 is a flowchart of the same driving operation.

FIG. 12 is an explanatory diagram of a reference proposal example of a teaching method.

FIG. 13 is a graph showing the relationship between the load current and the load.

[Explanation of reference numerals] 1 ... loader, 2 ... lathe, 3 ... work feeder, 5 ... elevating rod, 6 ... loader chuck, 7 ... spindle chuck, 10
... Loader control device, 14 ... Overall operation control means, 15 ... Partial operation control means, 19 ... Teaching decision value storage area, 21 ... Basic loader control means, 22 ... Running control means, 23 ... Teaching control means, 24 ... Skip moving means, 24a ... Horizontal axis skip moving means, 24b ... Gravity axis skip moving means,
25 ... Teaching position determining means, 25a ... Horizontal axis teaching position determining means, 25b ... Gravity axis teaching position determining means, 31 ... Y axis servo motor, 32 ... Z axis servo motor, 33, 34 ... Ammeter, 40 ... Main program , 41 ... Basic loader control program, P1 ... Unloading position, P2 ... Loading position, P3 ... Material loading position, P4 ... Workpiece unloading position, W ... Work

Claims (1)

[Claims] 1. A gravitational axis skip moving means for lowering a loader chuck holding a work in an automatic teaching process to press the loader chuck against the upper surface of a fixed object, and a load current of a motor of a lifting feed shaft of the loader chuck during the skip movement. A loader control device comprising: a gravity axis teaching position determining means for monitoring and reading a coordinate value of the feed axis when the current value decreases to a set reduction value, and determining a teaching position based on the read value.