JP2002200535A - Control method and controller for tool magazine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a control method and controller for a tool magazine that can shorten a tool indexing time below a conventional level. SOLUTION: A parameter storing part 14 stores data on a rotational speed, a time constant, a position loop gain and a speed loop gain, and a drive controlling part 13 generates an actuating command signal, a speed command signal and a current command signal sequentially on the basis of the rotational speed and the like stored in the parameter storing part 14 to thereby control a servomotor 6 for driving a chain to which a tool holding pot is coupled. A data storing part 16 stores a rotational speed and a time constant set according to the travel of the chain, and a parameter rewriting processing part 15 recognizes the travel of the chain, searches the data stored in the data storing part 16 for a rotational speed and a time constant corresponding thereto, and rewrites the data stored in the parameter storing part 14. The servomotor 6 is controlled on the basis of the rotational speed and the time constant rewritten according to the travel of the chain.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a control method and a control apparatus for a tool magazine for holding a replacement tool mounted on a main shaft of a machine tool, and more specifically, to the operation of a servomotor as a driving means for the tool magazine. The present invention relates to a control method and a control device for controlling

[0002]

2. Description of the Related Art A machine tool such as a machining center is provided with a tool magazine holding a large number of replacement tools mounted on a spindle, and a tool mounted on the spindle and a tool magazine. The tool held in the magazine is appropriately changed by a tool changing device.

[0003] Conventionally, as one of the tool magazines, a tool magazine in which a plurality of tool holders for holding tools are connected to an endless annular chain at predetermined intervals is known. This tool magazine is composed of the endless annular chain wrapped around a plurality of sprockets, a plurality of tool holders connected to the chain at predetermined intervals, and a drive unit including a servomotor for driving the sprocket. By driving the sprocket by the servo motor, the chain is rotated, whereby the predetermined tool holder is indexed to the exchange preparation position and held by the tool holder at the exchange preparation position. The tool and the tool mounted on the main shaft are appropriately replaced by a tool changing device.

[0004] In the field of machine tools, the operation time of each operating section has been shortened in order to reduce the processing time and the processing cost. Tool magazines are no exception, and the time for indexing tool holders is being reduced. If the tool indexing time of the tool magazine (that is, the preparation time of the next tool) is longer than the processing time of the current tool (the tool mounted on the main spindle), the next tool is completed even though the processing by the current tool is completed. Is not prepared, a waiting time for tool change is generated, and as a result, a problem that the machining time is prolonged occurs.

Therefore, as described above, the tool indexing time has been shortened conventionally, that is, the chain has been moved at high speed. However, if the movement amount of the chain is large, if the moving speed is increased, Therefore, there is a certain limit in increasing the moving speed, because the vibrations accompanying this increase. For this reason, tools that require a short machining time are held by neighboring tool holders so as to prevent the above-mentioned waiting time from being generated. Nevertheless, the reduction of the tool indexing time is still insufficient. It is not possible at the moment.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a tool magazine control method and a control device capable of reducing a tool indexing time as compared with the related art.

[0007]

Means for Solving the Problems and Effects There is provided a tool magazine attached to a machine tool for holding a plurality of replacement tools, the invention being described in claim 1 of the present invention for achieving the above object. It has an endless annular chain wrapped around a plurality of sprockets, a plurality of tool holders connected to the chain at predetermined intervals, and a servomotor, and drives the sprocket to rotate the chain. A drive magazine for driving and controlling the servo motor of a tool magazine provided with a drive unit for locating the tool holder at a predetermined position, wherein an operation command signal is generated based on a preset rotation speed and a time constant. Then, a speed command signal is generated by multiplying a deviation between the generated operation command signal and the current position signal fed back from the driving means by a position loop gain, and then obtaining a speed command signal. After multiplying the deviation between the speed command signal thus obtained and the current speed signal fed back from the driving means by a speed loop gain to generate a current command signal, the servo motor is driven and controlled based on the obtained current command signal. In the control method, the amount of movement of the chain associated with the index is recognized, and a rotation speed and a time constant corresponding to the recognized amount of movement are selected from rotation speeds and time constants set in advance according to the amount of movement. And controlling the servomotor by sequentially generating the operation command signal, the speed command signal, and the current command signal based on the selected rotation speed and time constant, and driving and controlling the servomotor. According to the method.

[0008] This control method can be suitably implemented by the device invention described in claim 2. That is, the invention described in claim 2 is a tool magazine attached to a machine tool and holding a plurality of replacement tools, and an endless annular chain wound around a plurality of sprockets, and a predetermined interval between the chain. A plurality of connected tool holders, a tool magazine having a servo motor, and driving means for rotating the chain by driving the sprocket to index the tool holders into predetermined positions; An apparatus for driving and controlling the servomotor, comprising: a parameter storage unit storing data relating to a preset rotation speed, a time constant, a position loop gain, and a speed loop gain; and a rotation speed stored in the parameter storage unit. And an operation command signal based on the time constant,
A speed command signal is generated by multiplying a deviation between the generated operation command signal and a current position signal fed back from the driving unit by a position loop gain stored in the parameter storage unit. After multiplying a deviation from a current speed signal fed back from the driving means by a speed loop gain stored in the parameter storage unit to generate a current command signal, the servo motor is driven based on the obtained current command signal. And a drive control unit for controlling the movement of the chain, the data storage unit storing a rotation speed and a time constant set according to the movement amount of the chain accompanying the indexing, and the movement of the chain accompanying the indexing. Recognizing the amount, retrieving the data stored in the data storage unit, and detecting the rotation speed according to the recognized movement amount of the chain. And extracting the time constant, in the extracted speed and time constants, providing a parameter rewriting process unit which rewrites the data stored in the parameter storage unit,
The drive control unit sequentially generates the operation command signal, the speed command signal, and the current command signal based on the rotation speed and the time constant rewritten by the parameter rewriting processing unit in accordance with the movement amount of the chain, and Drive motor,
The present invention relates to a tool magazine control device characterized in that it is controlled.

According to the control method and the control device, first, the parameter rewriting processing unit recognizes a moving amount of the chain to be moved in determining the next tool, and stores the moving amount in the data storage unit based on the recognized moving amount. The retrieved data is retrieved, a rotation speed and a time constant corresponding to the movement amount are extracted, and the data stored in the parameter storage unit is rewritten with the extracted rotation speed and time constant. Next, an operation command signal, a speed command signal, and a current command signal are sequentially generated by the drive control unit based on the rewritten rotation speed and time constant, and the servomotor is driven and controlled.

As described above, in the present invention, the rotation of the servomotor is controlled by the rotation speed and the time constant that are optimally set according to the amount of movement of the chain, and the movement of the chain is controlled. Specifically, when the movement amount of the chain is small, the rotation acceleration of the servomotor is increased and the rotation speed in the constant speed state is increased, so that the movement acceleration of the chain is increased and the movement speed in the constant speed state is increased. Conversely, when the moving amount is large, the rotational acceleration of the servomotor is reduced and the rotational speed in the constant speed state is reduced, so that the moving acceleration of the chain is reduced and the moving speed in the constant speed state is reduced. , The movement of the chain is controlled. If the moving amount of the chain is large, if the moving acceleration of the chain is increased or the moving speed is increased, the vibration of the chain will increase and smooth movement cannot be realized.However, if the moving amount is small, the moving acceleration of the chain will be increased. However, even if the moving speed is increased, no large vibration occurs. Therefore, the above control can be performed. Thus, when the movement amount of the chain is small, the chain is quickly started and moved at a high speed, and when the movement amount is large, the chain is slowly started and moved at a low speed. This makes it possible to reduce the tool indexing time.

The recognition of the amount of movement of the chain in the parameter rewriting processing section can be suitably performed by the invention described in claim 3. That is, in the invention described in claim 3, the amount of movement of the chain is recognized from the number of movements of the tool holder. Normally, the tool indexing command for the next tool is executed by the tool number code specified in the machining program, but the control device determines the number of the tool holder and the tool number held by this tool holder. When a tool indexing command is issued based on a tool number code, the number of tools to be moved can be recognized from the number of the tool holding unit corresponding to the command.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A tool magazine, a control method and a control device therefor according to a specific embodiment of the present invention will be described below with reference to the accompanying drawings. FIG. 1 is a partial front view showing a part of a tool magazine according to the present embodiment, and FIG. 2 is a cross-sectional view taken along a line II in FIG. 1. FIG. 3 is a block diagram showing a schematic configuration of the control device according to the present embodiment.

As shown in FIGS. 1 and 2, the tool magazine 1 of this embodiment has a plurality of sprockets 2 appropriately arranged on the same plane (however, FIG. 1 shows only one sprocket 2). ), An endless annular chain 3 wound around the sprocket 2, a plurality of tool holding pots 4 connected to the chain 3 at predetermined intervals, a servomotor 6 for driving the sprocket 2, and the like.

The tool holding pot 4 is formed of a cylindrical member and is connected to the chain 3 via a bracket 5. The tool holding pot 4 has a holding mechanism such as a ball lock mechanism inside, and holds the tool inserted into the cylinder by the holding mechanism. The servo motor 6 is fixedly mounted on a frame 7 appropriately disposed, and the sprocket 2 is fixed to an output shaft 6a. The servo motor 6 has a position detector for detecting the rotational position of the output shaft 6a.

Thus, in the tool magazine 1, when the sprocket 2 is rotationally driven by the servo motor 6 in the direction of arrow A or B, the chain 3 is thereby rotated in the direction of arrow C or D, The tool holding pot 4 connected thereto moves in the same direction, and a predetermined one thereof is indexed to the exchange preparation position.

On the other hand, as shown in FIG. 3, the control device 10 of the present embodiment has a program storage unit 11, a program analysis unit 1
2, a drive control unit 13, a parameter storage unit 14, a parameter rewrite processing unit 15, a data storage unit 16, and the like.
It should be noted that the control device 10 of the present embodiment constitutes a numerical control device of a machine tool, and FIG. 3 shows only those parts necessary for the description of the present embodiment.

The program storage section 11 is a function section for storing a machining program created in advance, and the program analysis section 12 analyzes the machining program stored in the program storage section 11 to store the replacement tool in the machining program. This is a function unit for extracting commands relating to preparation, tool change, spindle rotation, feed speed and moving position of the feed drive system, etc., and transmits the extracted commands for preparation of the replacement tool to the drive control unit 13 and the parameter rewriting unit 15. I do.

The parameter storage unit 14 stores data such as a rotation speed, a time constant, a position loop gain, and a speed loop gain necessary for controlling the servo motor 6, a pot number of the tool holding pot 4, and a tool held therein. The drive control unit 13 receives a preparation instruction for the next tool (including the tool number of the next tool) from the program analysis unit 12 and stores it in the parameter storage unit 14. The pot number of the tool holding pot 4 holding the commanded tool is recognized from the input data, and the chain number of the chain 3 is determined based on the recognized pot number and the pot number of the tool holding pot 4 that is currently in the exchange preparation position. The amount of movement, that is, the rotational position of the servo motor 6 is calculated, and the servo motor 6 is driven so as to reach the calculated rotational position.

More specifically, the drive control unit 13 generates an operation command signal based on the rotation position of the servo motor 6 calculated as described above, and the rotation speed and time constant stored in the parameter storage unit 14. A speed command signal is generated by multiplying a deviation between the generated operation command signal and the current position signal fed back from the servo motor 6 by a position loop gain stored in the parameter storage unit 14,
Next, a current command signal is generated by multiplying a deviation between the obtained speed command signal and a current speed signal fed back from the servo motor 6 by a speed loop gain stored in the parameter storage unit 14, and then obtains the obtained current. A command signal is transmitted to the servo motor 6 to control its operation.

The rotational position of the servo motor 6 is the rotational position in the direction indicated by the arrow A or B in FIG. 1 which requires less movement of the chain 3. That is, the chain 3 is moved in the direction of the arrow C or D in which the amount of movement is small.

The data storage section 16 stores the number of movements (T _M ) of the tool holding pot 4 in the preparation operation (indexing operation) of the replacement tool and the rotation set in accordance with the number of movements of the tool holding pot 4. This is a functional unit that stores the speed and the time constant in association with each other, and specifically stores the data shown in FIG. FIG. 4 exemplifies data on a tool magazine 1 having 40 tool holding pots 4. The specific meaning of the number of movements ( _TM ) will be described later.

Further, the parameter rewriting processing section 15 calculates the number of movements (T _M ) of the tool holding pot 4 in the indexing operation based on the signal transmitted from the program analysis section 12.
, And based on the recognized number of movements (T _M ), the data stored in the data storage unit 16 is searched to extract a rotation speed and a time constant according to the number of movements (T _M ). ,
A processing unit that rewrites data stored in the parameter storage unit 14 with the extracted rotation speed and time constant,
Specifically, the processing shown in FIG. 5 is executed.

Hereinafter, the operation of the tool magazine 1 and the specific processing in the control device 10 will be described focusing on the processing shown in FIG.

First, as described above, the program analysis unit 12 analyzes the machining program stored in the program storage unit 11, and issues a command (usually, the tool number of the next tool) for preparing the next tool from the machining program. When extracted, the extracted command is transmitted to the drive control unit 13 and the parameter rewriting processing unit 15.

As shown in FIG. 5, the parameter rewriting processing section 15 confirms a next tool indexing command (next tool number) transmitted from the program analysis section 12 (step S).
1), when receiving the indexing command following tool, then it recognizes the pot number T ₁ of the tool holding pot 4 holding the tool from the data stored in the parameter storage unit 14 (step S2). Note that the parameter rewriting processing unit 15
The pot number of the tool holding pot 4 recognized in this way is temporarily stored.

[0026] recognizing the pot number in step S2, then the parameter rewriting process unit 15, the recognized pot number T _1, based on the pot number T ₀ of the tool holding pot 4 at the current exchange ready position , according to equation 1 below, and then calculates the pot movement number T _M when determining the tool holding pot 4 to change preparation position (step S3).
The number of pot movements T _{M referred to} here is an arithmetically moved number, and does not necessarily match the number of movements of the tool holding pot 4 in actual indexing. Details will be described later.

[0027]

(Equation 1)

Next, the parameter rewriting process unit 15, calculated the pot moves number _{T M} is 1, or 2, or 38, or 39, or three or more 37 to determine if a whether or less (step S4) , The time constant and the rotation speed set according to the number of pot movements T _M are read from the data storage unit 16 (steps S5, S6,
In step S7), the data stored in the parameter storage unit 14 is rewritten with the obtained time constant and rotation speed (step S8, step S9, step S10).

Incidentally, as described above, the tool holding pot 4 is connected to the endless annular chain 3. For example, in FIG. 1, assuming that pot numbers are sequentially set counterclockwise from 1 for each tool holding pot 4, the tool holding pot 4 having the first pot number is indexed to the exchange preparation position. Then, when the second tool holding pot 4 is indexed, the second tool holding pot 4 is indexed to the exchange preparation position by driving the chain 3 in the direction of arrow D. On the other hand, No. 40 tool holding pot 4
In the case of indexing, the chain 3 is driven in the direction of arrow C, whereby the 40th tool holding pot 4 is indexed to the exchange preparation position. In this manner, the chain 3 is normally driven such that the amount of movement is minimized in indexing.

Therefore, the number of pot movements T _M calculated by the above equation 1 is simply a difference between numerical values related to pot numbers, and does not directly mean the number of movements of the tool holding pot 4 at the time of indexing. Therefore, in this example, I set the pot mobile number T _M corresponding to the movement number of the tool holding pot 4, and further, sets the constant and rotational speed when the response thereto. Specifically, in this example, the value of the number of pot movements T _{M at which} the number of movements of the tool holding pot 4 becomes one, that is, when the number of pot movements T _M is 1 and 39,
The value of the pot movement number T _{M at which} the number of movements of the tool holding pot 4 becomes two, that is, when the pot movement number T _M is 2 and 38, and the pot movement at which the number of movements of the tool holding pot 4 becomes three or more The value is divided into three when the value of the number T _M , that is, the number of pot movements T _M is 3 or more and 37 or less, and a time constant and a rotation speed are set according to each. Each data in the data table shown in FIG. 4 is A1 <B1 <C1,
C2 <B2 <A2.

Thereafter, the processing is continued until a processing end signal is received from the program analysis unit 12 (step S11).

In the drive controller 13, the number of movements of the tool holding pot 4, that is, the time constant and rotation speed stored in the parameter storage unit 14 rewritten according to the amount of movement, and the parameter storage An operation command signal, a speed command signal, and a current command signal are sequentially generated using a predetermined speed loop gain and a predetermined position loop gain stored in the unit 14, and the generated current signal is transmitted to the servo motor 6.

The servo motor 6 is driven by the number of movements of the tool holding pot 4, that is, a current signal generated according to the amount of movement, and drives the chain 3 through the sprocket 2.
To index the tool holding pot 4 to the exchange preparation position.

As described above, according to the tool magazine 1 and the control device 10 of the present embodiment, the number of movements of the tool holding pot 4, that is, the rotation speed and the time constant optimally set according to the movement amount, The rotation of the servomotor 6 is controlled, and the movement of the chain 3 is controlled. Specifically, when the moving amount of the chain 3 is small, the rotational acceleration of the servomotor 6 is increased and the rotational speed in the constant speed state is increased to increase the moving acceleration of the chain 3 and the moving speed in the constant speed state. When the moving amount is large, conversely, the rotational acceleration of the servo motor 6 is reduced and the rotational speed in the constant speed state is reduced to lower the moving acceleration of the chain 3 and the moving speed in the constant speed state is decreased. In this way, the movement of the chain 3 is controlled.
When the moving amount is large, if the moving acceleration of the chain 3 is increased or the moving speed is increased, the vibration of the chain 3 becomes large and smooth movement cannot be realized, but if the moving amount is small, the chain 3 moves. Even if the acceleration is increased and the moving speed is increased, very large vibration does not occur. Therefore, the above control can be performed.
Thus, when the moving amount of the chain 3 is small, the chain 3 is quickly started and moved at a high speed, and when the moving amount is large, it is slowly started and moved at a low speed. This makes it possible to reduce the tool indexing time.

As described above, one embodiment of the present invention has been described, but specific embodiments that can be adopted by the present invention are not limited thereto. For example, in the above example, the number of pot movements is divided into three, but the number of pot movements can be further finely divided.

[Brief description of the drawings]

FIG. 1 is a partial front view showing a part of a tool magazine according to an embodiment.

FIG. 2 is a cross-sectional view taken along a line II in FIG.

FIG. 3 is a block diagram illustrating a schematic configuration of a control device according to the embodiment.

FIG. 4 is a data table showing data stored in a data storage unit according to the embodiment.

FIG. 5 is a flowchart illustrating a processing procedure in a parameter rewriting processing unit according to the embodiment.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Tool magazine 2 Sprocket 3 Chain 4 Tool holding pot 6 Servo motor 10 Control device 11 Program storage unit 12 Program analysis unit 13 Drive control unit 14 Parameter storage unit 15 Parameter rewrite processing unit 16 Data storage unit

Claims (3)

[Claims] 1. A tool magazine attached to a machine tool and holding a plurality of replacement tools, an endless annular chain wound around a plurality of sprockets, and a plurality of tools connected to the chain at predetermined intervals. The servo motor of a tool magazine having a holder and a servo motor, and having a driving means for rotating the chain by driving the sprocket to index the tool holder to a predetermined position. A method of controlling, wherein an operation command signal is generated based on a preset rotation speed and a time constant, and a position loop gain is calculated based on a deviation between the generated operation command signal and a current position signal fed back from the driving means. Is multiplied to generate a speed command signal, and then the speed route is calculated by calculating the difference between the obtained speed command signal and the current speed signal fed back from the driving means. After generating a current command signal by multiplying a gain, the control method for driving and controlling the servomotor based on the obtained current command signal includes: recognizing a movement amount of the chain accompanying the indexing; From the preset rotation speed and time constant, a rotation speed and a time constant corresponding to the recognized moving amount are selected, and based on the selected rotation speed and the time constant, the operation command signal, A method for controlling a tool magazine, wherein a speed command signal and a current command signal are sequentially generated to drive and control the servomotor. 2. A tool magazine attached to a machine tool and holding a plurality of replacement tools, an endless annular chain wound around a plurality of sprockets, and a plurality of tools connected to the chain at predetermined intervals. The servo motor of a tool magazine having a holder and a servo motor, and having a driving means for rotating the chain by driving the sprocket to index the tool holder to a predetermined position. A parameter storage unit storing data relating to a preset rotation speed, time constant, position loop gain, and speed loop gain; and a rotation speed and time constant stored in the parameter storage unit. An operation command signal is generated, and a deviation between the generated operation command signal and a current position signal fed back from the driving means is calculated by the parameter. A speed command signal is generated by multiplying by the position loop gain stored in the data storage unit, and then a deviation between the obtained speed command signal and a current speed signal fed back from the driving unit is stored in the parameter storage unit. And a drive control unit for driving and controlling the servomotor based on the obtained current command signal after generating the current command signal by multiplying the current command signal by the speed loop gain. A data storage unit storing a rotation speed and a time constant set according to the movement amount; recognizing a movement amount of the chain associated with the indexing; searching data stored in the data storage unit; The rotation speed and the time constant according to the movement amount of the chain are extracted, and the extracted rotation speed and the time constant are used as data stored in the parameter storage unit. A parameter rewriting processing unit for rewriting data, wherein the drive control unit is configured to execute the operation command signal and the speed command signal based on the rotation speed and the time constant rewritten by the parameter rewriting processing unit in accordance with the movement amount of the chain. And a current command signal are sequentially generated to drive the servo motor,
A control device for a tool magazine, characterized in that it is controlled. 3. The tool magazine control device according to claim 2, wherein the amount of movement of the chain is recognized from the number of movements of the tool holder.