Servo System

Abstract

To execute servo control as quickly as possible even in a device after a change when the change is made on the device to which a motor servo-controlled by a servo system is attached.SOLUTION: A servo system includes a control device and one or more servo drivers, wherein a target device to be controlled can be changed, and a predetermined number of motors included in the changed target device and some or all of the one or more servo drivers are associated with each other. The servo system comprises: a detection unit configured to detect that the target device has been changed; and an adjustment unit configured to adjust a control structure in the respective one or more servo drivers so that servo control of the predetermined number of motors can be performed by the one or more servo drivers, based on configuration information of the predetermined number of motors of the changed target device when it is detected by the detection unit that the target device has been changed.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a servo system including a control device and a servo driver. [Background technology]

[0002] In a typical servo system, the servo driver that drives the motor performs control loop calculations related to position, speed, and current for servo control. A position command is issued to the servo driver from a higher-level control device (such as a PLC). To achieve this type of servo control, it is necessary to set control parameters corresponding to the motor to be driven in the control structure for that servo control. A control structure is a control calculation structure that realizes the control loop calculations for servo control.

[0003] Therefore, servo control of a motor requires setting control parameters in the control structure of the servo driver, and therefore, whenever the motor to be controlled changes, the control parameters to be set in the servo driver must be updated. For example, Patent Documents 1 and 2 disclose a configuration in which, when the model of the motor is changed, control parameters corresponding to the new model are read out and used for servo control. Furthermore, Patent Document 3 discloses a configuration in which, in a servo control device that switches between a synchronous motor and an induction motor, the control unit is configured with a control unit common to both motors and a control unit specific to each motor, thereby enabling motors with different control modes to be controlled by a single servo control device. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2013-48526 [Patent Document 2] Japanese Patent Application Laid-Open No. 2001-245488 [Patent Document 3] Japanese Patent Application Laid-Open No. 2000-270595 Summary of the Invention [Problem to be solved by the invention]

[0005] In processing lines in factories and other places where servo systems are used, the processing equipment used may be changed depending on the purpose. For example, when processing products with specific specifications, a dedicated processing equipment for the specific product may be used instead of a processing equipment used for products with other specifications. In this case, if the processing equipment controlled by the servo system is switched to another equipment while keeping the same servo system, the combination of the motor attached to the equipment, which is the direct target of servo control by the servo system, and the servo driver in the servo system will be disrupted. Generally, control parameters are determined based on the mechanical characteristics of the processing equipment (e.g., the total inertia of the load to be driven by the motor, mechanical stiffness, etc.) and the correlation between the power supply capacity of the servo driver and the electrical characteristics of the motor. Therefore, disruption of this combination makes it difficult to achieve optimal servo control of the motor.

[0006] Therefore, when the device to be controlled by the servo system is changed, it takes a lot of time to adjust the control parameters and other adjustments before the servo system can start servo control again, which can be a factor in reducing the yield in the process.

[0007] The present invention has been made in consideration of such problems, and aims to provide a technology that enables servo control to be performed in the device as quickly as possible after the device is replaced, when a device equipped with a motor that is servo-controlled by a servo system is replaced. [Means for solving the problem]

[0008] A servo system according to one aspect of the present disclosure includes a control device and one or more servo drivers, and is capable of changing a target device to be controlled, and in which a predetermined number of motors possessed by the changed target device are associated with some or all of the one or more servo drivers. The servo system is equipped with a detection unit that detects that the target device has been changed, and an adjustment unit that, when the detection unit detects that the target device has been changed, adjusts the control structure in each of the one or more servo drivers based on configuration information of the predetermined number of motors possessed by the changed target device, so that the one or more servo drivers can servo control the predetermined number of motors.

[0009] In a servo system configured in this manner, the device equipped with the motor servo-controlled by the system can be changed. That is, by switching the device to be servo-controlled by the servo system, the correspondence between one or more servo drivers of the servo system and the motors on the device side can be changed. Therefore, to enable such a usage mode, when the number of servo drivers included in the servo system is compared with the number of motors included in the device, which is the above-mentioned predetermined number, the former must be equal to or greater than the latter.

[0010] When the device controlled by a servo system can be changed in this way, multiple types of motors can be connected to a single servo driver as the driven device, allowing the servo system to be used efficiently. However, this configuration also means that various motors can be connected to the servo driver's power supply capacity. Generally, a motor is connected to a servo driver with a power supply capacity appropriate for the motor based on its electrical characteristics, and control parameters for the control structure of servo control are set based on the combination of the motor and servo driver. Therefore, to enable the device controlled by a servo system to be changed, appropriate control parameters must be set in each servo driver for each target device. The control structure is a control calculation structure for realizing the control loop calculation of servo control and is electrically formed within the servo driver.

[0011] Therefore, in the servo system disclosed herein, when the detection unit detects a change in the device to be controlled (target device), the adjustment unit adjusts the control structure of each servo driver based on configuration information of a predetermined number of motors included in the target device. The configuration information indicates the type of motor installed in the target device. The configuration information preferably identifies the motor from the perspective of the power supplied to the motor. By clarifying the configuration information, it becomes possible to determine what drive current should be supplied to one or more servo drivers of the servo system, i.e., the corresponding appropriate control parameters. Then, the adjustment unit reflects the control parameters corresponding to the actual combination of motor and servo driver in the control structure of each servo driver based on the configuration information of the motor in the target device after the change, thereby effectively reducing the effort required to start servo control of the motor when the device to be controlled by the servo system is changed.

[0012] Here, in the servo system, the adjustment unit may acquire control parameters used for servo control of the predetermined number of motors in the target device after the change from a corresponding servo driver associated with the predetermined number of motors among the one or more servo drivers or from a memory area of ​​the predetermined number of motors based on the configuration information, and set the acquired control parameters in the control structure of the corresponding servo driver. The control parameters are control parameters used for servo control of the motors, other parameters related to the control parameters, etc., and are information necessary for adjusting the control structure for servo control of the motors. For example, the control parameters are set according to the power supply capacity of the corresponding servo driver. The control parameters may be set as control parameters for servo-controlling the predetermined number of motors. The control parameters stored in the memory areas of the servo drivers or motors may be fixedly stored information, or may be information that can be updated by overwriting, etc., as needed. By including an adjustment unit that functions in this way, the servo system disclosed herein can quickly create a servo control environment for the motors installed in a new target device when the target device is changed.

[0013] Alternatively, in the servo system, when the detection unit detects that the target device has been changed, the adjustment unit may cause a corresponding servo driver, among the one or more servo drivers, that corresponds to the predetermined number of motors to perform a predetermined gain adjustment process for the predetermined number of motors, and set the execution result in the control structure of the corresponding servo driver. A known technique can be appropriately adopted as the predetermined gain adjustment process, for example, a process in which the corresponding servo driver measures the frequency response of the motor and calculates gain information such as a velocity loop gain and a position loop gain based on the frequency response. By including an adjustment unit that functions in this manner, the servo system disclosed herein can, when the target device is changed, quickly create a servo control environment that appropriately reflects the current state of the target device at the time of the change, i.e., aging due to use, etc.

[0014] Here, the servo system may further include a reception unit that receives a selection of a plurality of processing patterns for the predetermined gain adjustment processing, and in this case, the adjustment unit may change the content of the predetermined gain adjustment processing in accordance with the processing pattern received by the reception unit. By preparing gain adjustment processing patterns with different content according to the purpose in this way, a more suitable servo control environment can be quickly created.

[0015] In the servo system described above, the encoders of the predetermined number of motors may be connected to some or all of the one or more servo drivers via encoder cables. Furthermore, identification information for the motors connected to the encoder cables may be stored in a terminal on the servo driver side of the encoder cables. In this case, the adjustment unit may acquire configuration information for the predetermined number of motors based on the identification information stored in the encoder cables. Generally, encoder cables connect encoders and servo drivers as one path in a control structure for servo control. Therefore, by associating motor identification information with the encoder cables, the servo system disclosed herein can conveniently acquire configuration information for the motors in the target device. Note that other methods, such as having a user input or select configuration information, may also be used to acquire the configuration information.

[0016] Furthermore, in the servo system described above, the one or more servo drivers may each have an inter-driver communication unit that enables them to communicate with each other. In this case, when the detection unit detects that the target device has been changed, the adjustment unit may be configured such that, if the number of servo drivers is greater than the predetermined number, a first driver associated with a motor among the one or more servo drivers may notify a second driver associated with no motor among the one or more servo drivers via the inter-driver communication unit that the first driver is an unnecessary servo driver, based on the configuration information. When the number of servo drivers is greater than the predetermined number, some of the servo drivers become redundant. On the other hand, the redundant servo drivers have difficulty determining whether or not a motor will be connected to them. Therefore, the first driver, which already has a motor connected and knows the configuration information of the motor of the changed device, can notify a second driver associated with no motor that the second driver is an unnecessary servo driver via the inter-driver communication unit. As a result, the servo system can quickly prepare for servo control, i.e., adjust the control structure. [Effects of the Invention]

[0017] To enable servo control to be performed in a device after the change as quickly as possible when a device to which a motor servo-controlled by a servo system is attached is changed. [Brief explanation of the drawings]

[0018] [Figure 1] 1 is a first diagram showing a schematic configuration of a servo system disclosed in the present application. [Figure 2A] FIG. 2 is a diagram showing the flow of control signals in a servo driver included in the servo system disclosed in the present application. [Figure 2B] FIG. 1 is a diagram illustrating a control structure for servo control included in a servo system disclosed in the present application. [Figure 3]10 is a first flowchart showing the flow of processing executed when a device that is the target of servo control is changed in the servo system disclosed in the present application. [Figure 4] FIG. 10 is a diagram showing the signal flow for detecting a modified device using an encoder cable in the servo system disclosed herein. [Figure 5] FIG. 2 is a second diagram showing a schematic configuration of the servo system disclosed in the present application. DETAILED DESCRIPTION OF THE INVENTION

[0019] Hereinafter, embodiments of the present disclosure will be described in detail with reference to the drawings. In the drawings, the same or corresponding parts are denoted by the same reference numerals, and the description thereof will not be repeated. In the present disclosure, as one exemplary embodiment of the servo system, three servo drivers are connected to a control device (PLC). However, the number of servo drivers may be one or two. More than four is fine.

[0020] FIG. 1 is a diagram illustrating a schematic configuration of a servo system 1. The servo system 1 includes a control device PLC 5 and servo drivers 4, 4a, and 4b (hereinafter also referred to as "servo drivers 4, etc.") that generate drive currents for servo-controlling the motors to be controlled in accordance with position commands for each control axis generated by the PLC 5. Therefore, the servo system 1 has a maximum of three control axes. Here, the object to be driven by the servo system 1 is device 20 or device 30. Device 20 is a machining device having three internal motors, 21, 21a, and 21b, and device 30 is a machining device having three internal motors, 21, 21a, and 21b. In the embodiment of the present application, a user obtains a desired result by appropriately switching between driving device 20 and device 30. In other words, to obtain a desired result, the user needs to switch between device 20 and device 30 as the device driven by the servo system 1. The white arrows in FIG. 1 indicate the switching of the device.

[0021] Examples of the devices 20 and 30 include XY tables of machine tools, conveyance devices, and the arms of industrial robots with multiple joint axes. The motors 21, 21a, and 21b (hereinafter also referred to as "motors 21, etc.") of the device 20 and the motors 31 and 31a (hereinafter also referred to as "motors 31, etc.") of the device 30 are AC servo motors. The motors 21, etc. and 31, etc. are respectively equipped with encoders 22, 22a, 22b, 32, and 32a, which transmit signals related to the operation of each motor via feedback. These feedback-transmitted signals (hereinafter referred to as feedback signals) include, for example, position information regarding the rotational position (angle) of the rotational shaft of the motor 21, etc., and information on the rotational speed of the rotational shaft.

[0022] The PLC 5 generates an operation command signal related to the operation (motion) of each motor of the devices 20 and 30. The operation command signal generated by the PLC 5 is transmitted to each control axis having a position control unit 401 that performs control loop calculations related to position, a speed control unit 402 that performs control loop calculations related to speed, and a current control unit 403 that performs control loop calculations related to the drive current of the motor (see FIG. 2B). The output is supplied to a servo control unit 42 of the servo driver 4. Details of the servo control structure in the servo control unit 42 will be described later.

[0023] The PLC 5 includes a communication unit 51 and a detection unit 52. The communication unit 51 is a functional unit for communicating with the servo driver 4 or the like that supplies drive current to the motor that is the target of servo control by the PLC 5. Accordingly, communication units 41, 41a, and 41b are provided corresponding to the servo drivers 4 or the like that are the communication partners. The detection unit 52 is a functional unit that detects a change in the device (target device) that is the target of control by the servo system 1, i.e., a switch from driving device 20 to driving device 30, as described above, or vice versa. The switch in the device to be driven can be detected, for example, by detecting a user input to the PLC 5 to switch the device. Alternatively, the detection unit 52 can detect the type of motor connected to the servo driver 4 or the like when switching the device, and then detect which device has been switched to based on the combination of the detected motor types.

[0024] Furthermore, in addition to detecting a change in the device to be driven, the detection unit 52 acquires configuration information of the motors in the device after the change. The configuration information of the motors in the device is information about the number and types of motors the device has, and is information for clarifying the control target when servo control is performed by the servo driver 4 or the like. In the example shown in Fig. 1, the device 20 is equipped with three motors, including motor 21, and further, information about the type of each motor, i.e., information that allows for understanding electrical characteristics such as the power required for driving, is an example of the configuration information of the motors in the device.

[0025] Next, the functional units of the servo driver 4 and the like will be described. Since the functional units of the servo drivers 4, 4a, and 4b are all substantially the same, the following description will mainly focus on the servo driver 4. The servo driver 4 has a communication unit 41, a servo control unit 42, an adjustment unit 43, a reception unit 44, a storage unit 45, and a drive circuit 47. The communication unit 41 has already been mentioned, so the other functional units will mainly be described.

[0026] As described above, the servo control unit 42 has a servo control structure formed in the servo driver 4 and is a functional unit that performs control loop calculations for servo control of the associated motor. The servo control structure will be described with reference to FIGS. 2A and 2B. FIG. 2A illustrates the flow of control signals related to servo control of the motor 21, focusing on the servo driver 4. An operation command signal received from the PLC 5 is received by the communication unit 41 and provided to the servo control unit 42. The servo control unit 42 generates a current command for driving the drive circuit 47 using an internal servo control structure (see FIG. 2B). A feedback signal from the encoder 22 of the motor 21 is delivered to the servo control structure via an encoder cable 220. The drive circuit 47 is a so-called inverter device. AC power supplied from an AC power source (not shown) is used to power the drive circuit 47. In the present disclosure, the drive circuit 47 is a type that receives three-phase AC, but it may also be a type that receives single-phase AC. The drive circuit 47 generates a drive current for driving the motor 21.

[0027] 2B shows a servo control structure of the servo control unit 42. The servo control structure includes a position control unit 401, a speed control unit 402, and a current control unit 403. The position control unit 401 performs, for example, proportional control (P control). Specifically, a speed command vcmd is calculated by multiplying a position deviation, which is the deviation between a position command pcmd generated in the PLC 5 and a detected position, by a predetermined position proportional gain.

[0028] The speed control unit 402 performs, for example, proportional-integral control (PI control). The torque command τcmd is calculated by multiplying the integral of the speed deviation, which is the deviation between the speed command vcmd calculated by the control unit 401 and the detected speed, by a predetermined speed integral gain, and multiplying the sum of the calculation result and the speed deviation by a predetermined speed proportional gain. Also, the speed control unit 402 may perform P control instead of PI control.

[0029] The current control unit 403 outputs a current command Ccmd to the drive circuit 47 based on the deviation between the torque command τcmd calculated by the speed control unit 402 and the drive current supplied from the drive circuit 47 to the windings of the motor 21. Upon receiving the current command Ccmd, the drive circuit 47 generates a drive current for the motor 21. The current control unit 403 includes a filter (first-order low-pass filter) related to the torque command and one or more notch filters, and may have, as control parameters, cutoff frequencies related to the performance of these filters, etc.

[0030] In the servo control structure, a detected position signal and a detected speed signal calculated based on a detection signal from encoder 22 of motor 21 are fed back as feedback signals relating to position and speed to position control section 401 and speed control section 402, respectively. In order to perform control loop calculations by servo control section 42, it is necessary to set control parameters such as control gain, notch filter cutoff frequency, and other parameters that reflect the mechanical and structural conditions of motor 21, which is the direct drive target, and device 20 in which motor 21 is incorporated.

[0031] In the embodiment disclosed herein, different types of devices 20 and 30 are driven by the same servo system 1. The combination of servo drivers in the servo system 1 is fixed regardless of the device being driven. Therefore, depending on the combination of the servo system 1 and the device being driven, the combination of the servo driver's power supply capacity and the motor may deviate from the intended combination. For example, the motor 21 is originally driven by a servo driver with a maximum power supply capacity of 10 A, but when connected to the servo system 1, the maximum current of the servo driver 4 for the corresponding control axis may be 20 A. In such a case, a control parameter is required to limit the upper limit of the current supply by the servo driver 4 to 10 A and prevent electromagnetic problems from occurring when driving the motor 21.

[0032] Next, when the detection unit 52 detects a change in the target device, the adjustment unit 43 adjusts the servo control structure based on the configuration information of the motor in the changed device. In other words, the adjustment unit 43 is a functional unit that adjusts the control structure for servo control of the motor to be controlled so that the changed device can be suitably servo-controlled by the servo system 1. The configuration information of the motor in the changed device can be acquired from the detection unit 52. By acquiring the configuration information of the motor, the adjustment unit 43 can determine the type of motor to be installed in the changed device, i.e., the type of motor to be associated with the servo driver 4.

[0033] Then, the adjustment unit 43, having identified the type of motor to be controlled, adjusts the servo control structure necessary to servo-control the motor. The following two examples are given as specific examples of how the adjustment unit 43 adjusts the servo control structure. (First adjustment form) In the first adjustment form, the adjustment unit 43 acquires control parameters for the motor associated with the servo driver 4 (motor 21 if the changed device is device 20, or motor 31 if the changed device is device 30) from the storage unit 45 based on the configuration information of the motor, and adjusts the servo control structure using the acquired control parameters so that servo control of the motor becomes possible. The storage unit 45 is a memory that stores and stores information about the control parameters of the motors of each control axis related to the device to be controlled by the servo system 1. The storage of information about the control parameters in the storage unit 45 is performed in accordance with the adjustment process shown in FIG. 3, which will be described later. It is carried out inside.

[0034] According to the first adjustment mode, the servo system 1 is used to control the device. When the target device is changed, the servo control structure is quickly adjusted using information about the control parameters stored in the storage unit 45. Note that the information about the control parameters may be stored in a storage area of ​​the motor associated with the servo driver 4 or in an external storage area electrically connected to the servo driver 4, instead of in the storage unit 45 provided in the servo driver 4, and when the detection unit 52 detects a change in the device, the adjustment unit 43 may obtain the information about the control parameters from the adjustment area.

[0035] (Second adjustment form) In the second adjustment mode, the adjustment unit 43 causes the servo driver 4 to execute a gain adjustment process to acquire control gains to be set in the position control unit 401 and the speed control unit 402 of the servo control structure, among the control parameters for the motor associated with the servo driver 4, based on the motor configuration information. This gain adjustment process can employ well-known techniques, for example, adjusting the control gains based on the frequency response of each control axis. A control program for this gain adjustment process is stored in the servo driver 4 and can be executed by each servo driver 4. Gain adjustment may be performed individually for each control axis so that the gain adjustment process for each control axis does not affect other control axes. Alternatively, gain adjustment may be performed simultaneously for multiple control axes, taking into account the coordination of the control axes in the device. The adjustment unit 43 then reflects the control gains acquired by this adjustment process in the servo control structure of the motor.

[0036] According to the second adjustment mode, the control gain adjustment process is performed after the device is changed, so that the servo control structure can be adjusted using control gains that optimally reflect the current situation in the changed device. Depending on the device, friction, wear, rigidity, etc. within the device may change over time, which may cause the optimal control gain to fluctuate accordingly. Therefore, by performing the control gain adjustment process using the adjustment unit 43 upon device change and adjusting the servo control structure to reflect this, the performance of the changed device can be maximized. Note that the gain adjustment process only calculates some of the control gains, so for other control parameters, the control parameters obtained by the first adjustment mode described above can be used as needed.

[0037] Furthermore, while the gain adjustment process can obtain optimal control gains, it takes a certain amount of time to obtain them, which may hinder the device from quickly starting control after the change. Therefore, the adjustment unit 43 may be configured so that there are multiple patterns of gain adjustment processes that the adjustment unit 43 can execute, and the user can select which pattern to execute when executing the gain adjustment process. The user's pattern selection is input via the PLC 5, and the input result is accepted by the accepting unit 44. Multiple patterns of gain adjustment processes can be set so that they vary in processing time. Examples include a pattern in which frequency responses are acquired at multiple positions within the movable range of the control axis to obtain optimal control gains, a pattern in which frequency responses are acquired at only one predetermined position within the movable range of the control axis to obtain control gains, and a pattern in which gain adjustment is not performed. Furthermore, the gain adjustment process does not need to be performed on all control axes; it may be performed only on some control axes desired by the user. In this case, information about the control axes to be executed, along with a request for a gain adjustment process pattern, is also passed to the accepting unit of each servo driver.

[0038] Similarly to the servo driver 4, the servo driver 4a includes a communication unit 41a, a servo control unit 42a, an adjustment unit 43a, a reception unit 44a, a storage unit 45a, and a drive circuit 47a. Like the servo driver 4, the servo driver 4b also includes a communication unit 41b, a servo control unit 42b, an adjustment unit 43b, a reception unit 44b, a storage unit 45b, and a drive circuit 47b.

[0039] <Adjustment control> Here, the adjustment control executed in the servo system 1 will be described with reference to Fig. 3. The adjustment control is repeatedly executed by cooperation of the functional units of the PLC 5, servo driver 4, etc. shown in Fig. 1. In the description of this embodiment, it is basically assumed that device 30 has been connected to the servo system 1 until now, and that the connection is switched to device 20. When referring to a case other than this, this will be clearly stated. Therefore, the target device before the change is device 30, and the target device after the change is device 20.

[0040] First, in S101, it is determined whether a new device has been connected to the servo system 1, i.e., whether the device to be servo-controlled by the servo system 1 has changed. This determination process is performed by the detection unit 52. Here, acquisition of configuration information of the motor of the device 20 by the detection unit 52 will be described with reference to FIG. 4. FIG. 4 shows a state in which the device 20 is connected to the servo system 1, i.e., a state after the target device has been switched from the device 30 to the device 20. In this state, motors 21, 21a, and 21b are associated with the servo drivers 4, 4a, and 4b of the servo system 1, respectively. Encoders 22, 22a, and 22b of the motors 21, 21a, and 21b are connected by encoder cables 220, 220a, and 220b, respectively, and feedback signals from each motor are fed back to the servo control unit 42 of the associated servo driver 4, etc. (signal feedback paths are not shown).

[0041] Here, the encoder cable 220 connecting the servo driver 4 and the encoder 22 of the motor 21 will be described. A terminal 222 of the encoder cable 220 on the servo driver 4 side is provided with a memory 221 that stores identification information for identifying the motor 21. Therefore, when the terminal 222 is connected to the connector 450 of the servo driver 4, the servo driver 4 can access the identification information in the memory 221 via the terminal 222. As a result, the identification information in the memory is collected in the detection unit 52 of the PLC 5 via the communication unit 41. The encoder cables 220a and 220b connecting the servo drivers 4a and 4b to the encoders 22a and 22b of the motors 21a and 21b, respectively, have a similar configuration. When the terminals 222a and 222b are connected to the connectors 450a and 450b of the servo drivers 4a and 4b, respectively, the identification information of the motors 21a and 21b stored in the memories 221a and 221b is collected in the detection unit 52 of the PLC 5 via the communication units 41a and 41b.

[0042] As a result, the detection unit 52 can determine that the group of motors connected to the servo system 1 are motors 21, 21a, and 21b, and by comparing this information with the device information list created by the processing of S103 described later, which is information on the group of motors owned by devices that have been connected to the servo system 1 in the past, the detection unit 52 can determine that the device controlled by the servo system 1 is device 20. If the device that was previously the controlled object was device 30, the change in this information allows the detection unit 52 to determine that a new device has been reconnected to the servo system 1.

[0043] Alternatively, the user may input to the PLC 5 that a new device is to be connected to the servo system 1. In this case, the user's input enables the detection unit 52 to determine that a new device has been connected to the servo system 1. After the user's input, the detection unit 52 collects identification information of each motor from the memory 221 of the encoder cable 220 connected to the servo driver 4, etc., and acquires configuration information of the motors in the device 20.

[0044] If a positive determination is made in S101, the process proceeds to S102, and if a negative determination is made, the adjustment control is temporarily terminated. Then, in S102, it is determined whether the device newly connected to the servo system 1 is the first connection, that is, whether there is no history of past connection. This determination is made by the detection unit 52 based on the device information list created in S103. If a positive determination is made in S102, the process proceeds to S103, and if a negative determination is made, the process proceeds to S104.

[0045] In S103, when a device is connected to the servo system 1 for the first time, the detection unit 52 generates a device information list including information about the motor installed in the device, and stores information about control parameters for servo control of the motor in the device in the memory unit 45 or the like of each driver. The former device information list is generated when the device is unregistered (a device information list has not been created) using the configuration information of the motor in the device collected by the detection unit 52 as described above. The latter control parameter information is stored in the memory unit 45 or the like in association with the device information. This completes preparations for forming a servo control structure that appropriately corresponds to the changed target device when the target device is changed in the future. The control parameters initially stored may be input by a user using a known method, or may reflect the results of adjustments such as gain adjustment performed when the device is first started up. When the registration process in S103 is completed, the adjustment control is temporarily terminated. At this time, a servo control structure corresponding to the target device connected for the first time is formed in the servo driver 4 or the like of the servo system 1 along with the registration process.

[0046] A negative determination in S102 means that the target device is a device that has previously been connected to the servo system 1. Therefore, in S104, the detection unit 52 identifies the target device. In this embodiment, the device 20 is identified as the target device. Next, in S105, based on the motor configuration information of the target device identified in S104, control parameters for realizing servo control in the target device for the motors associated with each servo driver are read from the storage unit 45, etc. For example, if the device 20 is the target device, it can be understood from the device information list that the motor configuration is motors 21, 21a, and 21b. Therefore, the detection unit 52 instructs the adjustment unit 43, etc. of the servo driver 4, etc. to read information about the control parameters of the associated motor 21, etc. from the storage unit 45, etc., and the adjustment unit 43, etc. executes this instruction.

[0047] Then, in S106, a determination is made as to whether or not to perform gain adjustment processing in the device modified as described above. This determination is made by the adjustment unit 43 or the like based on a user's gain adjustment processing pattern request received by the reception unit 44 or the like. For example, the gain adjustment patterns received by the reception unit 44 or the like include a full adjustment pattern in which frequency responses are acquired at multiple positions in the movable range of the control axis and a control gain is calculated; a simple adjustment pattern in which frequency responses are acquired at one position in the movable range and a control gain is calculated; and a pattern in which gain adjustment processing is not performed. The user selects one of these patterns. If the user selects either the full adjustment pattern or the simple adjustment pattern, a positive determination is made in S106. If any other pattern is selected, a negative determination is made in S106. If the user desires to perform gain adjustment processing only on some control axes, that information is also passed to the reception unit 44 or the like. If a positive determination is made in S106, the process proceeds to S107; if a negative determination is made, the process proceeds to S109.

[0048] In S107, the adjustment unit 43 etc. executes the gain adjustment process shown in the second adjustment form described above based on the pattern request received by the reception unit 44 etc. As a result, the adjustment unit 43 etc. can obtain the control gain for the servo control structure that is most suitable for the current state of the device for each control axis or for the control axis requested by the user. Then, in the following S108, the control gain included in the control parameters read out in S105 is adjusted to the newly obtained control gain. At this time, information about the control parameters stored in the storage unit 45 etc. is also updated.

[0049] Then, in S109, the adjustment unit 43 or the like sets the control parameters reflecting the adjusted control gains if the gain adjustment process has been performed, or sets the control parameters read from the storage unit 45 or the like if the gain adjustment process has not been performed, in the servo control structure formed in the servo driver 4 or the like for each control axis. As a result, when a device connected to the servo system 1 is changed, a servo control structure corresponding to the changed device is suitably formed in the servo driver 4 or the like. As a result, even in the changed device, it becomes possible to perform servo control in that device as quickly as possible.

[0050] Here, as described above, when the target device is changed from device 30 to device 20, the number of motors corresponding to the maximum number of control axes of servo system 1, which is 3, are connected to each servo driver 4, etc., but conversely, when the target device is changed from device 20 to device 30, the number of motors (two motors) fewer than the maximum number of control axes of servo system 1, which is 3, are connected to servo drivers 4, 4a, and no motor is connected to servo driver 4b. In such a case, adjustment unit 43b of servo driver 4b receives a notification from detection unit 52 that, based on the motor configuration information of device 30, there is no motor corresponding to servo driver 4b in device 30, i.e., that servo driver 4b is unnecessary, and adjustment is made so that servo control by servo control unit 42b is not performed.

[0051] <Modification> A modified example of the servo system 1 disclosed herein will be described with reference to FIG. 5. FIG. 5 is a diagram illustrating a schematic configuration of the servo system 1 according to this modified example. The differences between the schematic configuration illustrated in FIG. 1 and the schematic configuration illustrated in FIG. 5 are that, in this modified example, a detection unit for detecting a change in the target device is formed in the servo driver 4, not in the PLC 5, and that the servo drivers 4, 4a, and 4b included in the servo system 1 are communicatively connected to each other via a communication line separate from the communication line with the PLC 5 (i.e., the communication line between the communication unit 51 of the PLC 5 and the communication unit 41, etc., of the servo driver 4, etc.). In relation to the latter, to enable communication between the servo drivers, the servo drivers 4, 4a, and 4b are provided with inter-driver communication units 48, 48a, and 48b, respectively, and communication via each inter-driver communication unit is referred to as "inter-driver communication." This inter-driver communication has a faster communication speed than communication with the PLC 5, and signals can be exchanged more quickly between the servo drivers because they do not require processing by the PLC 5.

[0052] The detection unit 46 is functionally the same as the detection unit 52 formed in the PLC 5, and is a functional unit that detects, for example, that a target device in the servo system 1 has been changed. The detection unit 46 also collects configuration information of the motors in the target devices, which is performed by the detection unit 52. Therefore, with regard to the collection of identification information of each motor shown in FIG. 4, in the servo driver 4, the identification information of the motor 21 stored in the memory 221 is passed to the detection unit 46, and the identification information of the motors 21a and 21b stored in the memories 221a and 221b is passed from the servo drivers 4a and 4b to the servo driver 4 via inter-driver communication and acquired by the detection unit 46. In addition, commands from the detection unit 46 to the adjustment units 43a and 43b of the servo drivers 4a and 4b (such as commands related to reading out the control parameters in S105 and the gain adjustment process in S107) are also exchanged via inter-driver communication.

[0053] It can be understood that the adjustment control shown in Fig. 3 can be performed even in the servo system 1 configured in this way. The detection unit 46 may be disposed in any of the servo drivers included in the servo system 1, but preferably, when the number of motors in the target device after the change is the minimum of one, and the connected servo driver is fixed to a specific servo driver (for example, servo driver 4), the detection unit 46 is disposed in the fixed servo driver. It is preferable to place the detection unit 46 in the position indicated by the arrows. Also, when the target device is changed from device 20 to device 30, if the number of motors in the target device after the change is less than the maximum number of control axes (3) of the servo system 1, there will be a servo driver to which no motor is connected. The adjustment unit of such a servo driver is notified via inter-driver communication from the detection unit 46 that there is no corresponding motor based on the motor configuration information of the target device after the change, i.e., that the servo driver is unnecessary. As a result, the servo driver to which no motor is connected is adjusted so that servo control is not performed.

[0054] <Appendix 1> A servo system (1) including a control device (5) and one or more servo drivers (4, 4a, 4b), in which a target device to be controlled can be changed, and a predetermined number of motors of the target device after the change can be associated with some or all of the one or more servo drivers (4, 4a, 4b), a detection unit (52, 46) that detects that the target device has been changed; an adjustment unit (43, 43a, 43b) that, when the detection unit (52, 46) detects that the target device has been changed, adjusts a control structure in each of the one or more servo drivers (4, 4a, 4b) based on configuration information of the predetermined number of motors possessed by the changed target device so that the one or more servo drivers (4, 4a, 4b) can servo-control the predetermined number of motors; A servo system comprising: [Explanation of symbols]

[0055] 1 Servo System 21, 21a, 21b, 31, 31a motors 5 PLC 20, 30 devices 42, 42a, 42b Servo control section 43, 43a, 43b adjustment section 44, 44a, 44b Reception 45, 45a, 45b storage section 46 Detection unit 52 Detection unit 220, 220a, 220b Encoder Cable 221, 221a, 221b memory

Claims

1. A servo system including a control device and one or more servo drivers, in which a target device to be controlled can be changed, and a predetermined number of motors of the target device after the change can be associated with some or all of the one or more servo drivers, a detection unit that detects that the target device has been changed; an adjustment unit that, when the detection unit detects that the target device has been changed, adjusts a control structure in each of the one or more servo drivers based on configuration information of the predetermined number of motors possessed by the changed target device so that the one or more servo drivers can servo-control the predetermined number of motors; A servo system comprising:

2. the adjustment unit acquires control parameters used for servo control of the predetermined number of motors in the target device after the change from a corresponding servo driver associated with the predetermined number of motors among the one or more servo drivers or from a memory area of ​​the predetermined number of motors based on the configuration information, and sets the acquired control parameters in the control structure of the corresponding servo driver.

2. The servo system according to claim 1.

3. the control parameters are control parameters for servo-controlling the predetermined number of motors, which are set according to the power supply capacity of the corresponding servo driver; 3. The servo system according to claim 2.

4. When the detection unit detects that the target device has been changed, the adjustment unit causes a corresponding servo driver, among the one or more servo drivers, that corresponds to the predetermined number of motors to execute a predetermined gain adjustment process for the predetermined number of motors, and sets the execution result in the control structure of the corresponding servo driver.

2. The servo system according to claim 1.

5. a reception unit that receives a selection of a plurality of processing patterns related to the predetermined gain adjustment processing, the adjustment unit changes the content of the predetermined gain adjustment process in accordance with the processing pattern accepted by the acceptance unit.

5. The servo system according to claim 4.

6. an encoder included in each of the predetermined number of motors is connected to a part or all of the one or more servo drivers by an encoder cable; Identification information of the motor to which the encoder cable is connected is stored in a terminal of the encoder cable on the servo driver side, the adjustment unit acquires configuration information of the predetermined number of motors based on the identification information stored in the encoder cable. The servo system according to any one of claims 1 to 5.

7. The one or more servo drivers each have an inter-driver communication unit that enables communication between the servo drivers, When the detection unit detects that the target device has been changed, if the number of the servo drivers is greater than the predetermined number, the adjustment unit notifies a first driver, which is associated with a motor among the one or more servo drivers, via the inter-driver communication unit, a second driver, which is not associated with a motor among the one or more servo drivers, that the first driver is an unnecessary servo driver, based on the configuration information. The servo system according to any one of claims 1 to 6.

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