Operation program generation device and operation program generation method for cogging torque correction

Abstract

The present invention reduces the burden on an operator by automating the creation of an operation program.　This operation program generation device for cogging torque correction comprises: a reception unit that acquires, from a numerical control device, machine configuration information that includes at least one among the number of poles and the number of slots of a motor or that includes information associated with at least one among the number of poles and the number of slots of the motor; an operation program generation unit that generates an operation program for cogging correction on the basis of the machine configuration information; and a transmission unit that transmits the created operation program to the numerical control device. At least one among the number of poles and the number of slots of the motor may be acquired from the numerical control device, or may be acquired, on the basis of the type of the motor, from a storage unit that stores a table in which at least one among the number of poles and the number of slots of the motor is associated with the type of the motor.

Description

Device and method for generating an operating program for cogging torque correction

[0001] The present disclosure relates to an operation program generating device and an operation program generating method for cogging torque correction, and more particularly to an operation program generating device and an operation program generating method for automatically generating an operation program for cogging torque correction.

[0002] Cogging torque and its correction are described in, for example, Patent Documents 1, 2, 3 and 4.

[0003] Patent Document 1 describes a motor control system that eliminates the need for work such as no-load operation before assembling a servo motor to a machine and performs optimal cogging compensation regardless of the combination of servo motor and servo amplifier. Specifically, Patent Document 1 describes a motor control system in which a position detector connected to the servo motor is provided with a compensation data storage memory that stores compensation data for the cogging torque of the servo motor, the compensation data is transmitted to the servo amplifier by a compensation data transmission / reception unit, the servo amplifier receives the compensation data from the position detector, and the cogging torque is compensated using the compensation data received from the position detector.

[0004] Patent Literature 2 describes a machine learning device that can easily minimize motor error amounts. Specifically, Patent Literature 2 describes that the machine learning device that learns conditions associated with correction amounts for commands in a motor control device includes: a state observation unit that observes state variables composed of at least one of: data on an error amount, which is the error between a position command for a rotor of a motor driven and controlled by the motor control device and an actual position of a feed mechanism; an operation program for the motor control device; a command in the motor control device that is one of a position command, a speed command, and a current command; data on workpiece machining conditions in a machine tool that has the motor control device; and data on the state of the machine tool that has the motor control device; and a learning unit that learns conditions associated with the correction amount used to correct the command in accordance with a training data set composed of the state variables.

[0005] Patent Document 3 describes an analysis device that can easily and quickly predict the performance of motors whose performance is determined by various design factors. Specifically, Patent Document 3 describes that the analysis device includes a magnetization calculation GUI module and a model creation and torque calculation GUI module. The analysis device launches the magnetization calculation GUI module to determine the magnetization distribution in the rotor magnet and create a magnetization distribution file. Next, the analysis device launches the model creation and torque calculation GUI module and uses the magnetization distribution file to create a torque result file and a magnetic flux density distribution file. The torque result file is the result of torque fluctuations for each rotor rotation angle. When calculations are performed without a drive current, cogging torque is calculated, and when a drive current is applied, driving torque is calculated. The actual torque is calculated by subtracting the cogging torque from the driving torque. The magnetic flux density distribution file displays the magnetic flux density distribution flowing in the motor according to the rotor rotation angle, the force acting on the rotor, and the eddy current distribution flowing in the stator.

[0006] Patent Document 4 describes a motor control device that can calculate an appropriate cogging torque compensation amount even when components other than cogging torque (such as gravity torque) are superimposed on a torque command during constant low-speed feed operation. Specifically, Patent Document 4 describes that the motor control device includes: a torque command observation unit that observes the torque command when the motor is operated at a constant speed; an approximation calculation unit that approximates a torque command approximation component from the observed torque command in an interval that is an integer multiple of the motor's cogging torque period; a second torque command calculation unit that calculates a second torque command by subtracting the torque command approximation component from the torque command; a second torque command frequency analysis unit that frequency analyzes the calculated second torque command to extract frequency components that are integer multiples of the fundamental frequency of the cogging torque; and a cogging compensation calculation unit that calculates a cogging compensation amount from the amplitude and phase of each extracted frequency component.

[0007] JP 2001-037280 A JP 2017-102613 A JP 2003-141186 A JP 2011-135645 A

[0008] Cogging torque correction for built-in synchronous motors is required after installation in a machine. Adjusting the cogging torque correction parameters requires a process that involves manually setting up measurements for the motor, creating an operation program, and measuring data multiple times. To automate the creation of the operation program in this process and reduce the burden on workers, an operation program generation device and operation program generation method for cogging torque correction are desired.

[0009] A first representative aspect of the present disclosure is an operation program generation device for cogging torque correction, comprising: a receiving unit that acquires machine configuration information from a numerical control device, the machine configuration information including at least one of the number of poles and the number of slots of a motor, or including information associated with at least one of the number of poles and the number of slots of the motor; an operation program generation unit that generates an operation program for cogging correction based on the machine configuration information; and a transmitting unit that transmits the created operation program to the numerical control device.

[0010] A second representative aspect of the present disclosure is a method for generating an operation program for cogging torque correction, in which a computer executes the following processes: acquiring machine configuration information from a numerical control device, the machine configuration information including at least one of the number of poles and the number of slots of a motor, or including information associated with at least one of the number of poles and the number of slots of the motor; generating an operation program for cogging correction based on the machine configuration information; and transmitting the created operation program to the numerical control device.

[0011] FIG. 1 is a block diagram showing an example configuration of a control system including an operation program generating device for cogging torque correction according to an embodiment of the present disclosure; FIG. 2 is a characteristic diagram showing an example of phase data and a torque command; FIG. 3 is a diagram showing an example of a generated program; FIG. 4 is a diagram showing an example configuration when a shaft driven by a motor is a rotating shaft having an eccentric load; FIG. 5 is a diagram showing an example operation program when a shaft driven by a motor is a rotating shaft having an eccentric load; and FIG. 6 is a flowchart showing an example of an operation program generating method. FIG. 7 is a block diagram showing an example configuration of a control system including an operation program generating device for cogging torque correction according to a modified example of an embodiment of the present disclosure.

[0012] Hereinafter, embodiments of the present disclosure will be described in detail with reference to the drawings. Fig. 1 is a block diagram showing an example configuration of a control system including an operation program generator for cogging torque correction according to an embodiment of the present disclosure. As shown in Fig. 1, the control system 10 includes an operation program generator 100 for cogging torque correction, a numerical control device 200, an industrial machine 300, and a cogging torque correction parameter adjustment device 400. The operation program generator 100 may be included in the cogging torque correction parameter adjustment device 400 or the numerical control device 200.

[0013] The operation program generation device 100 acquires mechanical configuration information including at least one of the number of poles and the number of slots of the motor from the numerical control device 200, generates an operation program for cogging torque correction (hereinafter referred to as the operation program) based on at least one of the acquired number of poles and the number of slots of the motor, and transmits the generated operation program to the numerical control device 200.

[0014] The numerical control device 200 generates control commands such as position commands based on the received operation program, outputs the generated control commands to the industrial machine 300, operates the motor of the industrial machine 300, and acquires operation waveform data from the industrial machine 300. The operation waveform data includes data necessary for cogging torque correction, such as a torque command and phase data (indicating the armature rotation angle, with one pole pair corresponding to 0 to 360 degrees) output from a rotary encoder or the like attached to the motor. The numerical control device 200 transmits the operation waveform data to the cogging torque correction parameter adjustment device 400, receives correction parameters from the cogging torque correction parameter adjustment device 400, and outputs them to the industrial machine 300. The correction parameters may also be output from the cogging torque correction parameter adjustment device 400 to the industrial machine 300 without going through the numerical control device. An example of the phase data and torque command is shown in the characteristic diagram of FIG. 2.

[0015] The industrial machine 300 is a machine tool, a robot, or the like. The industrial machine 300 includes a motor and a servo control device that controls the motor. The servo control device generates a torque command based on a control command such as a position command output from the numerical control device 200, controls the motor, and outputs operation waveform data to the numerical control device 200. The industrial machine 300 generates a cogging correction torque using the correction parameter output from the numerical control device 200 and adds it to the torque command of the servo control device, and the servo control device controls the motor based on the torque command after cogging torque correction. The correction parameter is generated by a cogging torque correction parameter adjustment device 400.

[0016] The cogging torque correction parameter adjusting device 400 outputs a correction parameter based on operational waveform data. Devices that output correction parameters based on operational waveform data are already known. For example, Patent Document 4 describes a cogging correction parameter calculating unit that generates and outputs correction parameters (frequency, amplitude, and phase) based on a torque command and a motor position (reference phase) output from an encoder attached to the motor.

[0017] Also, a configuration for generating cogging correction torque using correction parameters output from a cogging torque correction parameter adjustment device 400, which is used in an industrial machine 300, is already known. For example, Patent Document 4 describes a motor control device having a configuration for generating cogging correction torque using correction parameters (frequency, amplitude, and phase), adding the generated cogging correction torque to a torque command, and controlling the motor based on the torque command after cogging torque correction.

[0018] The following describes the configuration of the operation program generating device 100. The operation program generating device 100 includes a receiving unit 110, an operation program generating unit 120, and a transmitting unit .

[0019] The receiving unit 110 acquires machine configuration information including at least one of the number of poles and the number of slots of the motor from the numerical control device 200 .

[0020] The operation program generation unit 120 generates an operation program based on machine configuration information including at least one of the number of poles and the number of slots of the motor. First, the operation program generation unit 120 calculates the cogging torque generation period based on at least one of the number of poles and the number of slots of the motor included in the machine configuration information. Then, the operation program generation unit 120 creates an operation program so that cogging torque data for one or more periods can be acquired. The transmission unit 130 transmits the operation program to the numerical control device 200.

[0021] (Program Creation Example) As an example of program creation, an example of program creation will be described for a case where the axis driven by the motor is a rotating axis with an eccentric load. In the following explanation, an example of creating an operation program based on the number of poles and the number of slots of the motor acquired from the numerical control device 200 will be described. The receiving unit 110 acquires machine configuration information from the numerical control device 200, including the number of poles and slots of the motor, the eccentric load, and the direction of the gravitational load.

[0022] The operation program generation unit 120 calculates the period during which cogging torque occurs based on the number of poles and slots of the motor. For example, if the motor has eight poles and nine slots, the period during which cogging torque occurs is 5 degrees, which is 360 degrees divided by 72, the least common multiple of 8 and 9. Therefore, the operation program generation unit 120 generates an operation program that sets the amount of movement so that the motor rotation angle is 5 degrees or more. Figure 3 shows an example of a generated operation program. If the shaft driven by the motor is a rotating shaft (rotating tilt shaft) with an eccentric load, the operation program is generated taking the following points into consideration:

[0023] As shown in FIG. 4 , when the shaft driven by the motor is a rotating shaft (rotating tilt shaft) with an eccentric load, the influence of gravity changes depending on the angle θ. That is, the rotational direction component of gravity changes depending on the angle θ. Therefore, the force required to hold the shaft, i.e., the torque offset, changes depending on the angle θ. As such, in a rotating shaft with an eccentric load, the influence of gravity increases depending on the shaft angle, reducing the accuracy of cogging torque correction. To perform cogging torque correction with high accuracy, the receiving unit 110 obtains information on the eccentric load and the direction of the gravity load from the numerical control device 200 and creates a program to operate within a range where the influence of gravity (the force required to hold the shaft) is small. In the example of FIG. 4 , the influence of gravity is small when the angle θ is near 0 degrees.

[0024] The operation program generation unit 120 generates an operation program in which the angle θ of the A-axis (rotating axis) is in the range of −2.5 degrees to 2.5 degrees so that the cogging torque generation period is 5 degrees and the angle θ is near 0 degrees. Fig. 5 is a diagram showing an example of an operation program when the axis driven by the motor is a rotating axis with an eccentric load.

[0025] The above describes an example of creating a program that creates an operating program based on the number of poles and the number of slots of a motor. However, if one of the number of poles and the number of slots of the motor used in the industrial machine 300 is determined, the other of the number of poles and the number of slots of the motor can be obtained from the numerical control device 200, and an operating program can be generated based on the other of the number of poles and the number of slots of the motor.

[0026] Next, a description will be given with reference to a flowchart of an operation program generation method by the operation program generation device 100. Fig. 6 is a flowchart showing an example of the operation program generation method.

[0027] In step S11, the receiving unit 110 acquires, from the numerical control device 200, machine configuration information including at least one of the number of poles and the number of slots of the motor.

[0028] In step S12, the operation program generating unit 120 obtains the generation period of the cogging torque based on at least one of the number of poles and the number of slots of the motor.

[0029] In step S13, the operation program generator 120 creates an operation program so that data of the cogging torque for one cycle or more can be acquired.

[0030] In step S14 , the transmitting unit 130 transmits the operation program to the numerical control device 200 .

[0031] According to the operation program generating device 100 of this embodiment described above, the creation of an operation program can be automated, thereby reducing the burden on the operator.

[0032] (Modification) FIG. 7 is a block diagram showing an example configuration of a control system including an operation program generator for cogging torque correction according to a modification of an embodiment of the present disclosure. In the control system 10A, the operation program generator 100 of the control system 10 is replaced with an operation program generator 100A. The operation program generator 100A includes a storage unit 140 that stores a table that associates at least one of the number of poles and the number of slots of a motor with the motor type. The motor type is information associated with at least one of the number of poles and the number of slots of the motor. The receiving unit 110 acquires machine configuration information including the motor type from the numerical control device 200, and the operation program generator 120 searches the storage unit 140 based on the motor type and acquires at least one of the number of poles and the number of slots of the motor from the storage unit 140. The operation program generator 120 may include the storage unit 140 externally.

[0033] In order to realize the functional blocks included in the operation program generation device in each embodiment described above, the operation program generation device can be realized by hardware, software, or a combination of these. Here, being realized by software means being realized by a computer reading and executing a program.

[0034] To realize the components included in the operation program generation device by software or a combination of these, the operation program generation device includes a processing unit such as a CPU (Central Processing Unit). The processing unit functions as an execution unit. The operation program generation device also includes an auxiliary storage device such as an HDD (Hard Disk Drive) that stores various control programs such as application software or an OS (Operating System), and a main storage device such as a RAM (Random Access Memory) that stores data temporarily required for the processing unit to execute the program.

[0035] The operation program generating device then causes the arithmetic processing unit to read application software or an OS from the auxiliary storage device, and executes arithmetic processing based on the application software or the OS while expanding the loaded application software or the OS into the main storage device. Furthermore, based on the results of this arithmetic processing, the operation program generating device controls various hardware components included in the operation program generating device. This realizes the functional blocks of this embodiment.

[0036] The components included in the operation program generation device can be realized by hardware including electronic circuits, etc. When the operation program generation device is configured by hardware, some or all of the functions of the components included in the operation program generation device can be configured by integrated circuits (ICs), such as an ASIC (Application Specific Integrated Circuit), a gate array, an FPGA (Field Programmable Gate Array), or a CPLD (Complex Programmable Logic Device). Although examples have been described above in which the operation program generation device is realized by hardware, software, or a combination thereof, the same applies to the numerical control device and the cogging torque correction parameter adjustment device.

[0037] The program can be stored and supplied to a computer using various types of non-transitory computer-readable media. Non-transitory computer-readable media include various types of tangible storage media. Examples of non-transitory computer-readable media include magnetic recording media (e.g., hard disk drives), magneto-optical recording media (e.g., magneto-optical disks), CD-ROMs (Read Only Memory), CD-Rs, CD-R / Ws, and semiconductor memories (e.g., mask ROMs, PROMs (Programmable ROMs), EPROMs (Erasable PROMs), flash ROMs, and RAMs (Random Access Memory)). The program may also be supplied to the computer by various types of transient computer readable media.

[0038] According to the operation program generating device and operation program generating method of the present embodiment and the modified example described above, the creation of an operation program can be automated, reducing the burden on the operator.

[0039] Although the above-described embodiments are preferred embodiments of the present invention, the scope of the present invention is not limited to the above-described embodiments, and the present invention can be implemented in various modified forms within the scope that does not deviate from the gist of the present invention.

[0040] The following supplementary notes are further disclosed regarding the above embodiment: (Supplementary Note 1) An operation program generation device for cogging torque correction, comprising: a receiving unit (110) that acquires machine configuration information from a numerical control device (200), the machine configuration information including at least one of the number of poles and the number of slots of a motor, or information associated with at least one of the number of poles and the number of slots of the motor; an operation program generation unit (120) that generates an operation program for cogging correction based on the machine configuration information; and a transmitting unit (130) that transmits the created operation program to the numerical control device (200).

[0041] (Supplementary Note 2) The operation program generation device according to Supplementary Note 1 includes a memory unit (140) that stores a table that associates at least one of the number of poles and the number of slots of the motor with the motor type of the motor, wherein the receiving unit (110) acquires machine configuration information including the motor type, which is information associated with at least one of the number of poles and the number of slots of the motor, from the numerical control device (200), and the operation program generation unit (120) acquires at least one of the number of poles and the number of slots of the motor from the memory unit based on the motor type acquired from the numerical control device (200), and generates an operation program for cogging correction based on at least one of the number of poles and the number of slots of the motor.

[0042] (Supplementary Note 3) The operation program generating device according to Supplementary Note 1 or 2, wherein the operation program is a program including a movement corresponding to one or more cycles of the cogging torque of the motor.

[0043] (Supplementary Note 4) The device according to Supplementary Note 3, wherein the machine configuration information includes information regarding directions of eccentric loads and gravitational loads of the shafts driven by the motors, and the operation program generation unit (120) generates the operation program for operating in an area where the influence of the eccentric loads and the gravitational loads is small.

[0044] (Supplementary Note 5) A method for generating an operation program for cogging torque correction, in which a computer executes the following processes: a process of receiving machine configuration information from a numerical control device (200), the machine configuration information including at least one of the number of poles and the number of slots of a motor, or information associated with at least one of the number of poles and the number of slots of the motor; a process of generating an operation program for cogging correction based on the machine configuration information; and a process of transmitting the created operation program to the numerical control device (200).

[0045] REFERENCE SIGNS LIST 10 Control system 100 Cogging torque correction operation program generating device 110 Receiving unit 120 Operation program generating unit 130 Transmitting unit 140 Storage unit 200 Numerical control device 300 Industrial machine 400 Cogging torque correction parameter adjusting device

Claims

1. A receiving unit that acquires, from a numerical control device, mechanical configuration information including at least one of the number of poles and the number of slots of a motor, or information associated with at least one of the number of poles and the number of slots of the motor; an operation program generation unit that generates an operation program for cogging correction based on the mechanical configuration information; and a transmission unit that transmits the generated operation program to the numerical control device. An operation program generation device for cogging torque correction.

2. The operation program generation device according to claim 1, further comprising a storage unit that stores a table associating at least one of the number of poles and the number of slots of the motor with the motor type. The receiving unit acquires, from the numerical control device, mechanical configuration information including the motor type, which is information associated with at least one of the number of poles and the number of slots of the motor. The operation program generation unit acquires at least one of the number of poles and the number of slots of the motor from the storage unit based on the motor type acquired from the numerical control device, and generates the operation program for cogging correction based on at least one of the number of poles and the number of slots of the motor.

3. The operation program generation device according to claim 1 or 2, wherein the operation program is an operation program including a movement corresponding to one or more cycles of the cogging torque of the motor.

4. The operation program generation device according to claim 3, wherein the mechanical configuration information includes information regarding the directions of the eccentric load and the gravitational load of the shaft driven by the motor, and the operation program generation unit generates the operation program that operates in a region where the influence of the eccentric load and the gravitational load is small.

5. A method for generating an operation program for cogging torque correction, in which a computer executes a process of acquiring, from a numerical control device, mechanical configuration information including at least one of the number of poles and the number of slots of a motor, or information associated with at least one of the number of poles and the number of slots of the motor; a process of generating an operation program for cogging correction based on the mechanical configuration information; and a process of transmitting the generated operation program to the numerical control device.

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