Control device and computer-readable recording medium

Abstract

A control device according to the present disclosure comprises: a rotation speed acquisition unit that acquires the rotation speed of at least one among a spindle motor, a tool, and a workpiece driven in an industrial machine to be controlled in which a feeding speed is controlled so that a machining load reaches a target spindle load; a machining information acquisition unit that acquires motor characteristic information including the maximum output of each rotation speed, and tool information including the allowable load for each tool; a target spindle load changing unit that changes the target spindle load on the basis of the rotation speed, the motor characteristic information, and the tool information; and a control unit that controls the feeding speed so that the machining load reaches the target spindle load.

Description

Control device and computer-readable recording medium

[0001] The present disclosure relates to a control device and a computer-readable recording medium.

[0002] When machining a workpiece, there is adaptive control as a function of adjusting the feed rate so as to keep the machining load on the spindle at a target load (for example, Patent Document 1, etc.). The maximum output of the spindle motor varies depending on the rotational speed. Therefore, there is a technique for performing adaptive control according to the output characteristics (for example, Patent Document 2, etc.).

[0003] Japanese Patent Application Laid-Open No. 2018-173735, Japanese Utility Model Publication No. 62-186035

[0004] There is an allowable load for the tool used in machining. If machining continues with a load exceeding the allowable load, the tool will break. Since this non-allowance varies depending on the tool, it is necessary to limit the target load by the allowable load of the tool when using adaptive control. There is also a method of manually setting the target load considering the tool, but this is a burden on the user. Also, depending on the setting, there is a problem that the cycle time of machining becomes long. In the field, a technique that enables easy adaptive control considering the specifications of the tool is desired.

[0005] The control device according to the present disclosure solves the above problems by referring to the output characteristics of the spindle motor and the allowable load of the tool and setting the value that is lower than both as the target load.

[0006] And one aspect of the present disclosure is a rotational speed acquisition unit that acquires the rotational speed of at least any one of a spindle motor, a tool, and a workpiece driven in an industrial machine to be controlled that controls the feed rate so that the machining load becomes a target spindle load, motor characteristic information including the maximum output for each rotational speed, and tool information including the allowable load for each tool, a target spindle load change unit that changes the target spindle load based on the rotational speed, the motor characteristic information, and the tool information, and a control unit that controls the feed rate so that the machining load becomes the target spindle load.

[0007] This is a schematic hardware configuration diagram of the control device according to the first embodiment. This is a block diagram showing the schematic functions of the control device according to the first embodiment. This is a schematic diagram showing an example of a function that represents the characteristics of the maximum output with respect to the rotational speed of the spindle motor. This is a table diagram illustrating the relationship between the rotational speed of the spindle motor and the allowable load of the tool.

[0008] Embodiments of this disclosure will be described below with reference to the drawings. In the following description, components having the same or similar functions will be denoted by the same reference numerals. Duplication of these components may be omitted.

[0009] In this application, "based on XX" means "based on at least XX," and includes cases where it is based on another element in addition to XX. Furthermore, "based on XX" is not limited to cases where XX is used directly, but also includes cases where it is based on something that has been calculated or processed. "XX" is any element (for example, any information).

[0010] [First Embodiment] Figure 1 is a schematic hardware configuration diagram showing the main parts of a control device according to one embodiment of the present disclosure. The control device 1 of the present disclosure can be implemented as a control device for controlling industrial machinery such as machine tools and robots.

[0011] The CPU 11 in the control device 1 of this disclosure is a processor that controls the control device 1 as a whole. The CPU 11 reads a system program stored in the ROM 12 via the bus 22 and controls the entire control device 1 according to the system program. The RAM 13 temporarily stores temporary calculation data, display data, and various data input from external sources.

[0012] The non-volatile memory 14 is composed of, for example, a memory backed up by a battery (not shown) or an SSD (Solid State Drive), and its stored state is maintained even when the power to the control device 1 is turned off. The non-volatile memory 14 stores control programs and data read from an external device 72 via the interface 15, data and control programs input via the input device 71, and various data acquired from the industrial machine 3. The control programs and data stored in the non-volatile memory 14 may be expanded into the RAM 13 when executed or used. In addition, various system programs, such as known analysis programs, are pre-written in the ROM 12.

[0013] Interface 15 is an interface for connecting the CPU 11 of the control device 1 to an external device 72 such as a USB memory, CompactFlash®, or SD card. The external device 72 can read control programs and various data used to control the industrial machine 3, for example. Control programs and various data edited within the control device 1 can also be stored in the external device 72. The PLC (Programmable Logic Controller) 16 controls the industrial machine 3 and its peripheral devices (for example, tool changers, actuators such as robots, sensors attached to the industrial machine 3, etc.) by outputting signals via the I / O unit 17 according to the sequence program built into the control device 1. The PLC 16 also receives signals from various switches on the control panel and peripheral devices located on the main body of the industrial machine 3, performs the necessary signal processing, and then passes the signals to the CPU 11.

[0014] The display device 70 displays data loaded into memory, data obtained as a result of the execution of control programs and system programs, etc., which are output via the interface 18. In addition, the input device 71, which consists of a keyboard and a pointing device, transmits commands and data based on the operator's operations to the CPU 11 via the interface 19.

[0015] Interface 20 is an interface for connecting the CPU 11 of the control device 1 to a wired or wireless network 5. The network 5 may communicate using technologies such as serial communication (RS-485, for example), Ethernet® communication, optical communication, wireless LAN, Wi-Fi®, Bluetooth®, etc. At least one computer 4, fog computer 6, cloud server 7, etc. are connected to the network 5 and exchange data with the control device 1.

[0016] The axis control circuit 30, which controls the drive shafts of the industrial machine 3, receives a position command for the drive shaft from the CPU 11 and outputs a command for the drive shaft to the servo amplifier 40. The servo amplifier 40 receives this command and drives the servo motor 50, which is the drive shaft, to move each part of the industrial machine 3 along its respective axis. Each servo motor 50 has a built-in position sensor and feeds back the position feedback signal from this position sensor to the axis control circuit 30. The axis control circuit 30 performs feedback control of the servo motor 50 based on this position feedback signal. In the hardware configuration diagram of Figure 1, only one axis control circuit 30, servo amplifier 40, and servo motor 50 are shown, but in reality, as many as the number of axes on the industrial machine 3 to be controlled are provided. For example, when controlling a machine tool with a typical linear three-axis system, three sets of axis control circuits 30, servo amplifiers 40, and servo motors 50 are provided to move the spindle to which the tool is attached and the workpiece relative to each other in the linear three-axis direction (X axis, Y axis, Z axis).

[0017] The spindle control circuit 60 receives a spindle rotation command and outputs a spindle speed signal to the spindle amplifier 61. The spindle amplifier 61 receives this spindle speed signal and rotates the spindle motor 62 of the industrial machine 3 at the commanded rotational speed, driving the spindle. The spindle motor 62 rotates the tool or workpiece attached to the industrial machine 3. A position coder 63 is coupled to the spindle motor 62. The position coder 63 outputs a feedback pulse synchronized with the rotation of the spindle, and this feedback pulse is read by the CPU 11.

[0018] Figure 2 is a schematic block diagram showing the functions of the control device 1 according to the first embodiment of this disclosure. Each function of the control device 1 according to this embodiment is realized by the CPU 11 of the control device 1 shown in Figure 1 executing a system program and controlling the operation of each part of the control device 1.

[0019] The control device 1 of this embodiment includes a control unit 100, a rotation speed acquisition unit 120, a machining information acquisition unit 140, and a target spindle load changing unit 150. Furthermore, the RAM 13 to non-volatile memory 14 of the control device 1 have a control program 200 for controlling the industrial machine 3 pre-stored in them. In addition, a motor information storage unit 210, which is a region where information relating to the characteristics of each motor attached to the industrial machine 3 is pre-stored, and a tool information storage unit 220, which is a region where information relating to the tools used for machining in the industrial machine 3 is pre-stored.

[0020] The control unit 100 has the general functions required to control the industrial machine 3. It outputs commands to control the industrial machine 3 based on given commands. For example, the control unit 100 sequentially reads and analyzes blocks of the control program 200 and outputs position commands to move each part of the industrial machine 3 along a predetermined axis based on the analysis results of the commands from the blocks. It also outputs a rotation command for the spindle of the industrial machine 3 based on the analysis results of the commands from the blocks. The commands analyzed by the control unit 100 may be commands read from the control program 200. Alternatively, the commands analyzed by the control unit 100 may be commands input via the input device 71.

[0021] The control unit 100 performs known adaptive control when controlling the machining of a workpiece by the industrial machine 3, controlling the feed rate so that the load on the spindle during machining becomes the target spindle load. Since adaptive control has already been sufficiently explained in the aforementioned Patent Documents 1 and 2, a detailed explanation in this disclosure is omitted.

[0022] The rotational speed acquisition unit 120 acquires the rotational speed of at least one of the spindle motor 62, tool, or workpiece driven in the industrial machine 3. The rotational speed acquisition unit 120 may, for example, acquire the rotational speed per unit time of at least one of the spindle motor 62, tool, or workpiece commanded by the control program 200. Alternatively, it may acquire the rotational speed per unit time of the spindle motor 62 commanded by the control unit 100. The rotational speed acquisition unit 120 outputs the acquired rotational speed to the target spindle load changing unit 160.

[0023] The machining information acquisition unit 140 acquires motor characteristic information, including the maximum output of the spindle motor 62 at the rotational speed acquired by the rotational speed acquisition unit 120, and tool information, including the allowable load for each tool. The machining information acquisition unit 140 may also acquire motor characteristic information from, for example, a motor information storage unit 210 provided on the control device 1. Alternatively, it may acquire tool information from, for example, a tool information storage unit 220 provided on the control device 1. The machining information acquisition unit 140 outputs the acquired motor characteristic information and tool information to the target spindle load changing unit 160.

[0024] The motor information storage unit 210 has pre-stored information relating to the identification of the motor used in the industrial machine 3. This motor characteristic information includes at least the relationship between the motor's rotational speed and maximum output. The motor characteristic information may be stored, for example, in the form of a function or as table-formatted data. Figure 3 is a schematic diagram showing a graph of an example of a function that shows the characteristics of the maximum output with respect to the rotational speed of the spindle motor 62. By preparing such a function as motor characteristic information, the maximum output of the spindle motor 62 at a given rotational speed can be determined based on the rotational speed of the spindle motor 62.

[0025] The tool information storage unit 220 has tool information pre-stored in it relating to the specifications of the tools used in the industrial machine 3. This tool information includes at least the relationship between the motor rotation speed and the allowable load of the tool. The tool information may be stored, for example, in the form of a function or as table-formatted data. Figure 4 is a table diagram illustrating the relationship between the rotation speed of the spindle motor 62 and the allowable load of the tool. In this table, the allowable load of the tool up to a predetermined rotation speed is shown for each tool. For example, tool A, which is installed as tool number 01, has a rotation speed of 1000 [min -1 Larger than 2000 [min -1 The permissible load when it is less than or equal to 40% is 40%. By preparing such a table as tool information, for example, the permissible load of the tool at a given rotational speed can be determined based on the rotational speed of the spindle motor 62.

[0026] The target spindle load changing unit 160 changes the target spindle load in the adaptive control performed by the control unit 100 based on the rotational speed acquired by the rotational speed acquisition unit 120 and the motor characteristic information and tool information acquired by the machining information acquisition unit 140. The target spindle load changing unit 160 determines the maximum output of the spindle motor 62 at the given rotational speed based on the rotational speed and motor characteristic information. The target spindle load changing unit 160 also determines the allowable load of the tool at the given rotational speed based on the rotational speed and tool information. Subsequently, the target spindle load changing unit 160 determines the smaller value between the determined maximum output and the allowable load as the target spindle load. Then, it notifies the control unit 100 of the determined target spindle load.

[0027] Furthermore, the maximum output of the spindle motor 62, which is included in the motor characteristic information stored in the motor information storage unit 210, and the allowable load of the tool, which is included in the tool information stored in the tool information storage unit 220, are often provided separately. Therefore, the units of their values ​​may differ. In such cases, the target spindle load changing unit 160 should convert the units of both to the same unit, and then determine the target spindle load as the smaller of the maximum output of the spindle motor 62 and the allowable load of the tool.

[0028] The target spindle load changing unit 160 may determine the target spindle load by multiplying the target spindle load, which is determined based on the maximum output of the spindle motor 62 and the allowable load of the tool, by a predetermined ratio (for example, 0.95). Alternatively, it may determine the target spindle load by subtracting a predetermined difference in deviation from the determined target spindle load. By configuring it in this way, the target spindle load can be set to a value that has a certain margin from the maximum output of the spindle motor 62 and the allowable load of the tool, making it possible to set a safer target spindle load.

[0029] When the control unit 100 receives notification of the target spindle load from the target spindle load changing unit 160, it adjusts the feed rate to achieve the target spindle load during adaptive control. The control unit 100 may also set the abnormal spindle load to be a value obtained by multiplying the notified target spindle load by a predetermined ratio (for example, 1.05). Alternatively, the control unit 100 may set the abnormal spindle load to be a value obtained by adding a predetermined difference in deviation to the notified target spindle load. Furthermore, the control unit 100 may raise a warning to notify that there is an abnormality if the load on the spindle motor 62 exceeds the abnormal spindle load.

[0030] The control device 1 according to this embodiment, with the above configuration, can perform adaptive control while avoiding spindle overload and tool breakage by setting a target spindle load considering the maximum output of the spindle and the allowable load of the tool. Furthermore, by setting based on the allowable load, manual setting is not required, and the effect of shortening the cycle time is maximized.

[0031] [Other Embodiments] In the embodiments described above, the motor information storage unit 210 and the tool information storage unit 220 are provided on the RAM 13 or non-volatile memory 14 of the control device 1. However, these storage units may be provided on other computers, such as the fog computer 6. In such a configuration, the machining information acquisition unit 140 acquires motor characteristic information and tool information from an external computer via the network 5. By providing each storage unit on an external computer, motor characteristic information and tool information can be shared among multiple control devices 1. Furthermore, it becomes possible to reduce the management costs associated with this information.

[0032] While embodiments of this disclosure have been described in detail above, this disclosure is not limited to the individual embodiments described above. These embodiments can be added, replaced, modified, partially deleted, etc., in any way that does not depart from the spirit of the invention or from the idea and intent of this disclosure derived from the claims and their equivalents. For example, the order of operations and processes in the embodiments described above are shown as examples only and are not limited thereto. The same applies when numerical values ​​or mathematical formulas are used in the description of the embodiments described above.

[0033] The following are annotations to embodiments of the present disclosure. (Annotation 1) A control device (1) according to one aspect of the present disclosure includes: a rotation speed acquisition unit (120) that acquires the rotation speed of at least one of a spindle motor (62), a tool, or a workpiece driven in an industrial machine (3) to be controlled, which controls the feed rate so that the machining load becomes a target spindle load; a machining information acquisition unit (140) that acquires motor characteristic information including the maximum output for each rotation speed and tool information including the allowable load for each tool; a target spindle load changing unit (160) that determines the target spindle load based on the rotation speed, the motor characteristic information, and the tool information; and a control unit (100) that controls the feed rate so that the machining load becomes the target spindle load.

[0034] (Note 2) The tool information used by the control device (1) in other embodiments of the present disclosure includes an allowable load corresponding to the combination of the tool and the rotational speed. (Note 3) The target spindle load changing unit (160) in the control device (1) in other embodiments of the present disclosure converts the maximum output of the motor characteristic information and the allowable load of the tool information to the same units as the target spindle load, and then sets the smaller of the maximum output and the allowable load as the target spindle load.

[0035] (Note 4) The target spindle load changing unit (160) of the control device (1) in another aspect of the present disclosure further subtracts a predetermined percentage or difference of deviation from the obtained target spindle load. (Note 5) The control unit (100) of the control device (1) in another aspect of the present disclosure determines the abnormal spindle load as the value obtained by adding a predetermined percentage or difference of deviation to the target spindle load, and notifies that there is an abnormality when the machining load exceeds the abnormal spindle load.

[0036] (Note 6) A computer-readable recording medium according to one aspect of the present disclosure records a program that causes the computer to operate as a spindle motor (62) driven in an industrial machine (3) that controls the feed rate so that the machining load becomes the target spindle load, a rotation speed acquisition unit (120) that acquires the rotation speed of at least one of the tool or workpiece, a machining information acquisition unit (140) that acquires motor characteristic information including the maximum output for each rotation speed and tool information including the allowable load for each tool, a target spindle load changing unit (160) that changes the target spindle load based on the rotation speed, the motor characteristic information and the tool information, and a control unit (100) that controls the feed rate so that the machining load becomes the target spindle load.

[0037] 1 Control device 3 Industrial machine 4 Computer 5 Network 6 Fog computer 7 Cloud server 11 CPU 12 ROM 13 RAM 14 Non-volatile memory 15, 18, 19, 20 Interface 16 PLC 17 I / O unit 22 Bus 30 Axis control circuit 40 Servo amplifier 50 Servo motor 60 Spindle control circuit 61 Spindle amplifier 62 Spindle motor 63 Position coder 70 Display device 71 Input device 72 External device 100 Control unit 120 Rotation speed acquisition unit 140 Machining information acquisition unit 160 Target spindle load change unit 200 Control program 210 Motor information storage unit 220 Tool information storage unit

Claims

1. A control device comprising: a rotational speed acquisition unit that acquires the rotational speed of at least one of the spindle motor, tool, or workpiece driven in an industrial machine to be controlled, which controls the feed rate so that the machining load becomes the target spindle load; a machining information acquisition unit that acquires motor characteristic information including the maximum output for each rotational speed and tool information including the allowable load for each tool; a target spindle load changing unit that determines the target spindle load based on the rotational speed, the motor characteristic information, and the tool information; and a control unit that controls the feed rate so that the machining load becomes the target spindle load.

2. The control device according to claim 1, wherein the tool information includes an allowable load corresponding to the combination of the tool and the rotational speed.

3. The control device according to claim 1, wherein, if the maximum output of the motor characteristic information and the allowable load of the tool information differ from the units of the target spindle load, the target spindle load is set to the smaller of the maximum output and the allowable load after converting them to the same units as the target spindle load.

4. The control device according to claim 1, wherein the target spindle load changing unit further subtracts a predetermined percentage or difference of deviation from the obtained target spindle load.

5. The control device according to claim 1, wherein the control unit determines an abnormal spindle load as the value obtained by adding a predetermined percentage or difference deviation to the target spindle load, and notifies that there is an abnormality when the machining load exceeds the abnormal spindle load.

6. A computer-readable recording medium that records a program causing the computer to operate as: a rotational speed acquisition unit that acquires the rotational speed of at least one of the spindle motor, tool, or workpiece driven in an industrial machine to be controlled, which controls the feed rate so that the machining load becomes the target spindle load; a machining information acquisition unit that acquires motor characteristic information including the maximum output for each rotational speed and tool information including the allowable load for each tool; a target spindle load changing unit that changes the target spindle load based on the rotational speed, the motor characteristic information, and the tool information; and a control unit that controls the feed rate so that the machining load becomes the target spindle load.

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