Motor amplifier and motor control method

Abstract

To provide a motor amplifier that does not stop when switching control modes.SOLUTION: A motor amplifier 1 controls rotation of a motor 4. A communication unit 12 acquires commands and control values relating to control modes of the motor 4. A control setting unit 100 also sets the control values acquired by the communication unit 12 even when the control mode is different from the current control mode. When the communication unit 12 acquires a control mode switching command, a mode control unit 110 starts control with the control value set by the control setting unit 100.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention particularly relates to a motor amplifier that controls the rotation of a motor and a method for controlling the motor amplifier. [Background technology]

[0002] Conventionally, there exist a host device such as a PLC (Programmable Logic Controller) that transmits a position command, an encoder that acquires the rotational position of a motor, and a motor amplifier connected to this encoder. Some of these motor amplifiers can be switched to various control modes by commands from a higher-level device. These control modes include, for example, a position setting mode that sets the position of the shaft rotated by the motor, a torque control mode that controls the torque, and a speed control mode that controls the speed.

[0003] On the other hand, Patent Document 1 describes an electric vehicle equipped with a control device that determines a switching modulation rate for switching the inverter control mode from an overmodulation control mode to a square wave control mode based on at least one of the altitude of the current location and the temperature of the motor. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2014-027763 A Summary of the Invention [Problem to be solved by the invention]

[0005] However, in conventional motor amplifiers, when switching control modes, the motor amplifier's control of the motor may temporarily stop in order to start operation upon receiving a command in the new control mode after the switching, which may cause the motor to suddenly change speed or vibrate. The control device described in Patent Document 1 cannot accommodate such switching of control modes from a higher-level device.

[0006] The present invention has been made in consideration of the above circumstances, and has an object to provide a motor amplifier in which control of the motor does not stop when the control mode is switched, thereby solving the above-mentioned problems. [Means for solving the problem]

[0007] The motor amplifier of the present invention is a motor amplifier that controls the rotation of a motor, and is characterized in that it comprises a communication unit that acquires commands and control values ​​regarding the control mode of the motor, a control setting unit that sets the control value acquired by the communication unit even if it is for a control mode different from the current control mode, and a mode control unit that starts control with the control value set by the control setting unit when the command to switch the control mode is acquired by the communication unit. With this configuration, control of the motor is not interrupted when the control mode is switched.

[0008] The motor amplifier of the present invention is characterized in that the control mode switching is a switching to a torque control mode that controls the torque of the motor shaft, the control setting unit sets the torque value as the control value for the torque control mode, and when the mode control unit obtains a command to switch to the torque control mode, it controls the torque of the motor shaft with the set control value. By configuring in this way, the control mode can be switched smoothly.

[0009] The motor amplifier of the present invention is characterized in that the control mode switching is from a speed control mode, which controls the speed of the shaft of the motor, to a torque control mode. By configuring in this way, the control mode can be switched smoothly.

[0010] The motor amplifier of the present invention is characterized in that the control mode switching is from a position control mode, which controls the position of the shaft of the motor, to a torque control mode. By configuring in this way, the control mode can be switched smoothly.

[0011] The motor amplifier of the present invention is characterized in that the control mode switching is switching to a speed control mode that controls the speed of the motor shaft, the control setting unit sets the speed value as the control value for the speed control mode, and when the mode control unit obtains a command to switch to the speed control mode, it controls the speed of the motor shaft at the set speed value. By configuring in this way, the control mode can be switched smoothly.

[0012] The motor amplifier of the present invention is characterized in that the control mode switching is from a position control mode, which controls the position of the shaft of the motor, to a speed control mode. By configuring in this way, the control mode can be switched smoothly.

[0013] The motor amplifier of the present invention is characterized in that the control mode switching is from a torque control mode, which controls the torque of the motor shaft, to a speed control mode. By configuring in this way, the control mode can be switched smoothly.

[0015] The motor control method of the present invention is a motor control method executed by a motor amplifier that controls the rotation of a motor, which acquires a control value related to a control mode of the motor, sets the acquired control value even if the acquired control value is for a control mode different from a current control mode, acquires a command related to the control mode of the motor, and starts control using the set control value if the command is a command to switch the control mode. By configuring in this way, there is no downtime when the control mode is switched. Effect of the Invention

[0016] According to the present invention, even if a control value that is not used in the current control mode is acquired, the control value can be set by a control setting unit, and when a command to switch the control mode is acquired, control is started using the set control value, thereby providing a motor amplifier that prevents control of the motor from being stopped when the control mode is switched. [Brief description of the drawings]

[0017] [Figure 1] 1 is a system configuration diagram of a control system according to an embodiment of the present invention. [Diagram 2] 4 is a flowchart of a motor control process according to the embodiment of the present invention. [Diagram 3] FIG. 4 is a conceptual diagram of a motor control process according to the embodiment of the present invention. [Figure 4] FIG. 1 is a conceptual diagram of a conventional motor control process. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0018] <Embodiment Mode> [Configuration of control system X] The configuration of a control system X according to an embodiment of the present invention will be described with reference to FIG. The control system X according to this embodiment is an example of a control system that controls the servo of the motor 4 according to a command from a higher-level device 2. The control system X includes a motor amplifier 1, a higher-level device 2, an encoder 3, and a motor 4.

[0019] The motor amplifier 1 is a control device connected to a higher-level device 2 and an encoder 3. In this embodiment, the motor amplifier 1 acquires various commands transmitted from the higher-level device 2 and control values ​​associated with these commands, and controls the drive of a motor 4 based on these.

[0020] Here, the motor amplifier 1 according to this embodiment can be switched between a plurality of control modes in response to a command from the higher-level device 2. The control modes according to this embodiment include, for example, a position setting mode, a torque control mode, and a speed control mode. Of these, in this embodiment, the position setting mode is a mode in which the axial position (angular position) of the shaft S rotated by the motor 4 is set (controlled) to a position specified by a control value. The torque control mode is a mode in which torque control is performed to maintain the torque of the shaft S at a torque set by a control value. The speed control mode is a mode in which speed control is performed to rotate the shaft S to maintain the speed set by the control value. Each control mode will be described in detail later.

[0021] The motor amplifier 1 and the higher-level device 2 are connected by a field network such as EtherCAT. On the other hand, the motor amplifier 1 and the encoder 3 are connected by a dedicated line or a serial communication line, for example, and power for servo-driving the motor 4 is also supplied. This power is supplied to the motor 4 via the encoder 3 or directly. Furthermore, the motor amplifier 1 can also calculate a torque value indicating the torque of the shaft S by using a current feedback value of the motor control of the motor 4. In addition, the motor amplifier 1 can also obtain state information such as temperature from the encoder 3 or the motor 4. Furthermore, the motor amplifier 1 may be capable of responding to a data request from the higher-level device 2. The detailed functional configuration of the motor amplifier 1 will be described later.

[0022] The higher-level device 2 is a device for a client (customer) that transmits commands. The higher-level device 2 is, for example, a PLC or a logic board of various devices equipped with a microcontroller. Specifically, the higher-level device 2 transmits a control signal for controlling the motor 4 as a command to the motor amplifier 1. The period for transmitting this command, the amount of data transmitted at one time, etc. are arbitrary (variable) depending on the configuration of the field network and the configuration of the higher-level device 2. In addition, the higher-level device 2 may perform periodic communication even without a command. Furthermore, the higher-level device 2 can also obtain the detected position data of the motor 4 and other data from the motor amplifier 1.

[0023] The encoder 3 is a device that acquires the rotational position of the motor. In this embodiment, the encoder 3 detects position data of the rotational position of the shaft S related to the rotation axis A of the motor 4, and transmits the position data to the motor amplifier 1 as angle information. For this reason, the encoder 3 includes, for example, a magnetic or optical angle detection mechanism, a control calculation means such as an MPU (Micro Processing Unit, microcontroller), a DSP (Digital Signal Processor), or an ASIC (Application Specific Integrated Circuit), and a non-temporary recording medium such as a RAM (Random Access Memory) that holds angle information and temporary data, and a ROM (Read Only Memory) that records a control program. The encoder 3 may also include a temperature sensor that measures the temperature of the motor 4 or the encoder 3 itself. In addition, the encoder 3 may be capable of transmitting signals from the temperature sensor, the battery voltage sensor, and the like as a type of data different from the position data.

[0024] In response to a control signal from the motor amplifier 1, the motor 4 rotates a shaft S, which is a rotary output shaft, about a rotary axis A as a central axis. The motor 4 is a typical servo motor or the like that includes a rotor, bearings, a stator, a bracket, and the like.

[0025] [Motor amplifier 1 configuration] To explain in more detail, in this embodiment, the motor amplifier 1 includes a communication unit 12 and a control unit 10.

[0026] The communication unit 12 is a communication means that receives communication on the field network, acquires commands addressed to the motor amplifier 1 from the higher-level device 2, and transmits the commands to the control unit 10. The communication unit 12 includes, for example, a circuit (physical layer) for communication in a field network.

[0027] The control unit 10 is a control and calculation means that servo-drives the motor 4 based on a command obtained from the communication unit 12, and controls the position of the shaft S. The control unit 10 includes control and calculation means such as an MPU, a DSP, and an ASIC. In this embodiment, the control unit 10 can control the motor 4 by referring to angle information acquired from the encoder 3, information from various other sensors, torque values, and the like, depending on the control mode.

[0028] The storage unit 11 is a non-transitory recording medium such as a RAM, a ROM, etc. The control unit 10 and the storage unit 11 may be integrally configured. The storage unit 11 stores a control program for the motor amplifier and various data.

[0029] Next, the functional configuration of the motor amplifier 1 will be described. The control unit 10 includes a control setting unit 100 and a mode control unit 110 . The storage unit 11 stores the control value data 200 .

[0030] The control setting unit 100 also sets the control value acquired by the communication unit 12 when it is for a control mode different from the current control mode. Specifically, the control setting unit 100 stores a control value associated with a command obtained from the higher-level device 2 in the storage unit 11 as control value data 200. This allows the control setting unit 100 to set a control value required when switching the control mode before switching. Specifically, the control setting unit 100 sets a position value, which is an angular position value, as a control value for the position control mode. Alternatively, the control setting unit 100 sets a torque value as a control value for the torque control mode. Alternatively, the control setting unit 100 sets a speed value as a control value for the speed control mode.

[0031] When the mode control unit 110 receives a command to switch the control mode via the communication unit 12, the mode control unit 110 starts control using the control value set by the control setting unit 100. When the mode control unit 110 receives a command to switch to the torque control mode, the mode control unit 110 controls the torque of the shaft S of the motor 4 at a torque value that is a set control value. When the mode control unit 110 receives a command to switch to the speed control mode, it controls the speed of the shaft S of the motor 4 at a speed value that is a set control value. In addition, in this embodiment, the mode control unit 110 can calculate the difference between the current speed value of the shaft S of the motor 4 and the set speed value, and complement the difference value to smoothly change the speed of the shaft of the motor 4.

[0032] In this embodiment, the communication unit 12 also acquires commands and control values ​​related to the control mode of the motor 4.

[0033] The control value data 200 is data including control values ​​set for each control mode, which are transmitted together with a command from the higher-level device 2. Of these, the control value for the position setting mode is set to, for example, an angular position value corresponding to the angle information of the encoder. This angular position is an absolute value indicating the rotational position of the shaft S of the motor 4 corresponding to the accuracy of the encoder 3, for example, 17 bits to 32 bits. The control value for the torque control mode is set to, for example, a torque value. This torque value is an absolute value of, for example, 8 bits to 32 bits corresponding to a torque feedback value. The control value for the speed control mode is an absolute value of, for example, 8 bits to 32 bits corresponding to a speed value of the angular velocity of the shaft S.

[0034] [Motor control processing] Next, a motor control process according to the embodiment of the present invention will be described with reference to FIG. 2 and FIG. In the motor control process of this embodiment, a control value related to the control mode of the motor 4 is acquired in response to a command. The acquired control value is also set in case it is for a control mode different from the current control mode. If a command related to the control mode of the motor 4 is then acquired and this command is a command to switch the control mode, control is started with the set control value. In the motor control process of this embodiment, the control unit 10 mainly executes a control program stored in the storage unit 11 in cooperation with each unit, using hardware resources. The motor control process of this embodiment will be described below step by step with reference to the flowchart of FIG.

[0035] (Step S101) First, the control setting unit 100 and the communication unit 12 perform a command control value acquisition process. The communication unit 12 acquires various commands for the motor amplifier 1 and control values ​​associated with these commands via the factory network. The control setting unit 100 interprets (decodes) the acquired command and control value, and temporarily stores them in the memory unit 11. This command includes a command related to the control mode of the motor 4. In addition, the control setting unit 100 can always accept commands other than the current control mode.

[0036] Specifically, the communication unit 12 acquires, as commands, for example, a control mode switching command for switching (setting) the control mode, a position command for setting a position in a position setting mode, a torque command for setting a torque value in a torque setting mode, a speed command for setting a speed in a speed control mode, etc. Other commands include, for example, a control mode monitor command for notifying the higher-level device 2 of the control mode, a torque monitor command for notifying the higher-level device 2 of a torque feedback value, a speed monitor command for notifying the higher-level device 2 of the speed of the shaft S, etc. For example, a position command is accompanied by a set value including an angular position value as a control value, a torque command is accompanied by a set value including a torque value as a control value, and a speed command is accompanied by a set value including a speed value as a control value.

[0037] (Step S102) Next, the control setting unit 100 judges whether or not it has acquired control values ​​for a control mode different from the current one. Specifically, the control setting unit 100 judges whether or not the control value transmitted together with the command is a control value for a control mode different from the current control mode. In this embodiment, for example, when the current control mode is a position setting mode, the control setting unit 100 judges "Yes" when it acquires a speed command or a torque command and their control values. Alternatively, for example, when the current control mode is a torque control mode, the control setting unit 100 judges "Yes" when it acquires a position command or a speed command and their control values. Alternatively, for example, when the current control mode is a speed control mode, the control setting unit 100 judges "Yes" when it acquires a position command or a torque command and their control values. In other cases, the control setup section 100 determines No.

[0038] If the answer is Yes, the control setting unit 100 advances the process to step S103. If the answer is No, the control setting unit 100 advances the process to step S104.

[0039] (Step S103) When a control value for a control mode different from the current control mode is acquired, the control setting unit 100 performs a control value setting process. The control setting unit 100 also sets the control value if it is for a control mode different from the current control mode. Specifically, in this embodiment, for example, the control setting unit 100 sets a setting value including a position value, a setting value including a torque value, or a setting value including a speed value acquired as a control value to the control value data 200 regardless of the current control mode.

[0040] Specifically, in this embodiment, in the position control mode, the control value of the position command is acquired and used for operation, and other control values ​​are not used. However, even if the host device 2 is currently in the position control mode, it may obtain a torque feedback value from the motor 4 and calculate an optimal torque value. The host device 2 may then be capable of transmitting the optimal torque value as a control value together with a torque command. As a specific example, the host device 2 may obtain a torque value while specifying a position to rotate when tightening a screw, and calculate a final tightening force as the torque value. Similarly, even if the host device 2 is currently in the position control mode, it may be possible to obtain the speed value of the motor 4 and transmit an optimal speed value as a control value together with a speed command before switching to the speed control mode. Alternatively, the host device 2 may be possible to transmit a speed value according to the next operation together with a speed command.

[0041] In these cases, the control setting unit 100 can receive control values ​​to be used in the torque control mode or the speed control mode while operating in the position control mode. The control setting unit 100, which has received these control values, sets them in the control value data 200 before switching to the torque control mode or the speed control mode. That is, the control setting unit 100 can set in the control value data 200 each control value to be used after the control mode is changed, regardless of the control mode, or before the control mode is changed.

[0042] (Step S104) Next, the mode control unit 110 judges whether the acquired command is a command to switch the control mode. At this time, the mode control unit 110 judges as Yes when the acquired command is a mode switching command to switch to a control mode different from the current control mode. The mode control unit 110 judges as No in other cases. If the answer is Yes, the mode control unit 110 advances the process to step S105. If the answer is No, the mode control unit 110 advances the process to step S106.

[0043] (Step S105) When a control mode switching command is acquired, the mode control unit 110 performs an operation mode switching process. The mode control unit 110 checks that the control values ​​to be used in the post-switching control mode have been set by referring to the control value data 200. Then, the mode control unit 110 starts control using the control values ​​required for the post-switching control mode from the set control values.

[0044] For example, when the mode control unit 110 acquires a control mode switching command from the position control mode or the speed control mode to the torque control mode, it controls the torque of the shaft S of the motor 4 using the set torque value as the control value. Alternatively, when the mode control unit 110 receives a control mode switching command, for example, to switch from the position control mode or the torque control mode to the speed control mode, it may control the speed of the shaft S of the motor 4 using the set speed value as the control value. As a result, when the control mode is switched, the device can immediately operate in the new mode, thereby enabling the control mode to be switched smoothly.

[0045] In this embodiment, in these cases, by performing an interpolation process such as linear interpolation as described below, it becomes possible to switch the torque or speed even more smoothly.

[0046] An example of performing the interpolation process when switching from the position control mode to the speed control mode will be described in detail with reference to Fig. 3. In each graph in Fig. 3, the horizontal axis indicates the passage of time on the same time axis, and the vertical axis indicates an example of each value. 3(a) shows that a control mode switching command is sent from the upper device 2 and the position control mode is switched to the speed control mode. That is, the value indicating the control mode (control mode value) is changed. 3(b) is a graph showing the control mode value transmitted to the upper device 2 by the control mode monitor command. As shown here, a time lag occurs in the change of the control mode value because the control mode after switching is actually performed and then the control mode after switching is transmitted to the upper device 2. Fig. 3(c) is a graph showing the change in the position value in the position control mode. In the position control mode, when the angular position changes, the change (slope) can be calculated as the velocity Vp. Note that after switching to the velocity control mode, the position value may be fixed.

[0047] 3(d) is an example in which the control value of the speed value is set by the speed command. In this embodiment, the thin line indicates an example in which the speed command is input before the mode switching is executed, and the speed value Vv associated with the speed command is set as the control value. Here, as shown in FIG. 3(c), the speed at the time when the position control mode is switched to the speed control mode is a speed value Vp, and in this example, the speed value Vp is smaller than the speed value Vv. In this embodiment, even if the velocity value Vp and the velocity value Vv differ in this way, the current velocity value Vp and the set velocity value Vv are set in advance, so it is possible to smoothly complement them to become Vv.

[0048] Specifically, the mode control unit 110 can change the internal speed command VvI, which is the final control value, to the value of the speed command Vv over a specific time Td according to the speed difference Vd between the operating speed Vp in the position control mode and the speed value Vv of the speed command. Among these, Td = kVd …… Equation (1) can be calculated as such. That is, the time Td is proportional to the speed difference Vd, and the larger the speed difference, the larger Td. Here, "k" in Equation (1) is a constant that can be set according to the load and inertia. Also, if a speed command is input before mode switching, it is possible to calculate the time Td before switching the operating mode.

[0049] Also, assuming the elapsed time after speed mode switching is t, the internal speed command VvI can be calculated by the following linear interpolation formula (2) or formula (3). When t < Td: VvI = (Vd / Td) × t + Vp …… Equation (2) When t > Td: VvI = Vv = Vd + Vp …… Equation (3)

[0050] In this way, by changing the internal speed command to Vv over time, it is possible to suppress a sudden change in speed. Figure 3(e) shows the actual operation (speed) of the motor 4. In this example, it is operating smoothly from the speed value Vp to the speed value Vv.

[0051] In the above example, although the example of switching from the position control mode to the speed control mode has been described, the same type of interpolation is possible even for switching from the position control mode to the torque control mode. That is, the control mode switch may be from the position control mode to the torque control mode.

[0052] Similarly, the control mode switch may be from the torque control mode to the speed control mode, and the same type of interpolation can be performed. Alternatively, the control mode may be switched from a speed control mode to a torque control mode, and similar complementation can be performed.

[0053] Here, if the control value to be used in the post-switching control mode has not yet been set, the mode control unit 110 waits to receive it from the higher-level device 2, and then starts control in the post-switching operation mode.

[0054] (Step S106) When a command other than the control mode switching command is acquired, the mode control unit 110 processes the other command. The mode control unit 110 performs various processes according to the commands. For example, when a control mode monitor command is received, the mode control unit 110 notifies the higher-level device 2 of the current control mode, when a torque monitor command is received, the torque feedback value, and when a speed monitor command is received, the speed of the shaft S.

[0055] Alternatively, in this embodiment, when a control mode switching command for switching from the torque control mode or the speed control mode to the position control mode is acquired, the position of the shaft S of the motor 4 may be controlled after waiting for the acquisition of the position value of the position command acquired after the control mode switching command. This is because in the torque control mode or the speed control mode, the angular position of the shaft S changes from moment to moment, and therefore control must be started after a position command is acquired. Specifically, the mode control unit 110 acquires angle information from the encoder 3, and controls the angular position of the shaft S of the motor 4 according to a position value, which is a control value included in the position command. This concludes the motor control process according to the embodiment of the present invention.

[0056] [Main Effects of the Present Embodiment] With the above configuration, the following effects can be obtained. In a conventional motor amplifier, when switching the drive of a motor from a position control mode to another control mode, control is disabled while a different control value is being set after the control mode is switched.

[0057] The switching of control modes in this conventional motor amplifier will be described with reference to FIG. FIG. 4(a), like FIG. 3(a), shows that a control mode switching command is sent from the upper device 2 and the position control mode is switched to the speed control mode. FIG. 4(b) shows that, like FIG. 3(b), a time lag occurs since the control mode monitor command transmits the control mode to the higher-level device 2 after switching. Fig. 4(c) is a graph showing the change in the position value in the position control mode, similar to Fig. 3(c). In the position control mode, the speed Vp can be calculated based on the gradient of the position value. Here, in a conventional motor amplifier, before the control mode is switched, only the control value commands (position value, speed value, torque value) corresponding to the control mode at that time are accepted and operation is performed.

[0058] 4(d) shows that after the control mode switching is completed, the motor starts to operate by receiving the control value commands (position value, speed value, torque value) in the new control mode after the control mode switching is completed. That is, in the conventional motor amplifier, after confirming that the control mode has been switched by the control mode monitor, the motor receives any one of the position command, speed command, and torque command transmitted from the upper device 2 and sets this control value.

[0059] FIG. 4(e) shows the change in actual motor operation (speed) in a conventional motor amplifier. As described above, in a conventional motor amplifier, after switching the control mode, the amplifier receives a command in the new control mode and starts operating. For this reason, during the period from switching the control mode to accepting the speed command, there is a temporary state in which no control value is set by the speed command. If there is no speed command, even if only temporarily, the motor stops operating. This period can be up to about 50 milliseconds, for example. The motor is then controlled by receiving the command after switching. In other words, when switching the control mode while the motor is operating, the command is not connected smoothly, and the motor moves as if it is temporarily stopped.

[0060] As described above, it was difficult for conventional motor amplifiers to switch control modes continuously, which resulted in large changes in motor speed, causing vibrations and noise. However, in the technology described in Patent Document 1, there is no description of such switching of control modes.

[0061] In contrast, the motor amplifier 1 according to an embodiment of the present invention is a motor amplifier that controls the rotation of a motor 4, and is characterized by comprising a communication unit 12 that acquires commands and control values ​​related to the control mode of the motor 4, a control setting unit 100 that sets the control value acquired by the communication unit 12 even if it is for a control mode different from the current control mode, and a mode control unit 110 that starts control with the control value set by the control setting unit 100 when a command to switch the control mode is acquired by the communication unit 12. With this configuration, the control values ​​to be used after the control mode is set in advance before switching from the control mode, and thus the motor 4 does not stop temporarily. Therefore, the motor can be controlled continuously, and the control mode can be switched smoothly. In other words, when the control mode is switched, continuous control can be performed, and the motor can immediately operate in the new control mode. In this way, by eliminating the period when control is not possible, the motor 4 can be controlled continuously, the switching becomes smooth, and the generation of vibrations and noise can be suppressed.

[0062] In the motor amplifier 1 according to the embodiment of the present invention, the control mode is switched to a torque control mode in which the torque of the shaft of the motor 4 is controlled, and the control setting unit 100 sets a torque value as a control value for the torque control mode, and when the mode control unit 110 receives a command to switch to the torque control mode, it controls the torque of the shaft of the motor 4 with the set control value. With this configuration, the torque control value is received and set before switching to the torque control mode, which allows the control mode to be switched smoothly.

[0063] In the motor amplifier 1 according to the embodiment of the present invention, the control mode is switched from a speed control mode, which controls the speed of the shaft of the motor, to a torque control mode. With this configuration, the control mode can be smoothly switched from the speed control mode to the torque control mode.

[0064] In the motor amplifier 1 according to the embodiment of the present invention, the control mode is switched from a position control mode, which controls the position of the motor shaft, to a torque control mode. With this configuration, the control mode can be smoothly switched from the position control mode to the torque control mode.

[0065] In the motor amplifier 1 according to the embodiment of the present invention, the control mode is switched to a speed control mode for controlling the speed of the shaft of the motor 4, and the control setting unit 100 sets a speed value as a control value for the speed control mode, and when the mode control unit 110 receives a command to switch to the speed control mode, it controls the speed of the shaft of the motor 4 at the set speed value. With this configuration, when switching from the position control mode to the speed control mode, the speed control value is received and set before switching to the speed control mode, which allows the control mode to be switched smoothly.

[0066] In the motor amplifier 1 according to the embodiment of the present invention, the control mode is switched from a position control mode, which controls the position of the motor shaft, to a speed control mode. With this configuration, the control mode can be smoothly switched from the speed control mode to the torque control mode.

[0067] In the motor amplifier 1 according to the embodiment of the present invention, the control mode is switched from a torque control mode, which controls the torque of the motor shaft, to a speed control mode. With this configuration, the control mode can be smoothly switched from the position control mode to the torque control mode.

[0068] In the motor amplifier 1 according to the embodiment of the present invention, the mode control unit 110 calculates the difference between the current shaft speed value of the motor 4 and the set speed value, and changes the shaft speed of the motor 4 by complementing the difference value. With this configuration, the speed can be changed more smoothly when switching from the position control mode to the speed control mode, thereby making it possible to further reduce the generation of vibrations and noise.

[0069] Other Embodiments In the above embodiment, when switching from the torque control mode or the speed control mode to the position control mode, the angular position of the shaft S is controlled after waiting for a position command after switching. However, even when switching to the position control mode, it is possible to set a position value before switching and use the set position value when a control mode switching command is acquired. That is, when the mode control unit 110 acquires a control mode switching command for switching from the torque control mode or the speed control mode to the position control mode, for example, the mode control unit 110 may control the position of the shaft S of the motor 4 using the set position value as the control value. In this case, the mode control unit 110 can also adjust and synchronize the speed of the shaft S in accordance with the period of command transmission so that, once the position value is set, it becomes the position value of the position command immediately after obtaining the control mode switching command.

[0070] In the above embodiment, an example has been described in which, when switching from the position control mode to the speed control mode, if the speed value is different from the current speed, linear interpolation is performed to gradually change the speed of the shaft S. However, a configuration may be possible in which this linear interpolation is not performed. In this case, the motor 4 may be controlled so that the speed value becomes the set value immediately after the control mode switching command is acquired.

[0071] Alternatively, in addition to linear interpolation, the speed may be gradually changed by non-linear interpolation, S-curve, spline interpolation, or other interpolation formulas. Furthermore, it is also possible to change this complement equation depending on switching from the position control mode to the speed control mode, switching from the position control mode to the torque control mode, switching from the torque control mode to the speed control mode, and switching from the speed control mode to the torque control mode. By configuring in this way, it becomes possible to perform optimal complementation in accordance with the configuration of the control system.

[0072] In the above embodiment, the control values ​​are set before and after switching of the control mode. However, it is also possible to set a plurality of control values ​​in accordance with the flow of commands (macro) from the upper device 2, such as screw tightening and a predetermined operation of the arm. In other words, the above-mentioned complementation method may be changed in accordance with the change of a plurality of control modes, and optimal complementation may be performed. For this reason, it is also possible to perform optimal control by using so-called AI, such as a convolutional neural network. With this configuration, the motor 4 can be controlled more smoothly.

[0073] It goes without saying that the configurations and operations of the above-described embodiments are merely examples and can be modified as appropriate without departing from the spirit and scope of the present invention. [Explanation of symbols]

[0074] 1 Motor amplifier 2. Upper device 3 Encoder 4 Motor 10 Control section 11 Storage section 12 Communications Department 100 Control setting section 110 Mode control section 200 Control value data A-axis S shaft X Control System

Claims

1. A motor amplifier that controls the rotation of a motor, a communication unit for receiving commands and control values ​​related to a control mode of the motor; a control setting unit that sets the control value acquired by the communication unit even if the control value is for a control mode different from a current control mode; a mode control unit that starts control at the control value set by the control setting unit when the command to switch the control mode is received by the communication unit, The mode control unit is Calculating a difference between a current value of the shaft speed of the motor and a set value of the speed, and changing the shaft speed of the motor by complementing the difference value; A speed command is input before the control mode is switched, and Td, which is a specific time during which the speed value is changed, is calculated by the following formula (1). Td=kVd... Formula (1) Here, Td is proportional to the speed difference Vd, and the larger the speed difference, the larger Td is. "k" is a constant that is set according to the load and inertia. A motor amplifier comprising:

2. The control mode switching is a switching to a torque control mode for controlling a torque of a shaft of the motor, the control setting unit sets a value of the torque as the control value for the torque control mode; When the mode control unit receives a command to switch to the torque control mode, the mode control unit controls the torque of the motor shaft with the set control value.

2. The motor amplifier according to claim 1 .

3. The control mode switching is a switching from a speed control mode for controlling the speed of the shaft of the motor to the torque control mode.

3. The motor amplifier according to claim 2.

4. The control mode switching is a switching from a position control mode for controlling the position of the shaft of the motor to the torque control mode.

3. The motor amplifier according to claim 2.

5. The control mode switching is a switching to a speed control mode for controlling a speed of a shaft of the motor, the control setting unit sets the speed value as the control value for the speed control mode; When the mode control unit receives a command to switch to the speed control mode, Controlling the speed of the motor shaft at the set speed value 2. The motor amplifier according to claim 1 .

6. The control mode switching is a switching from a position control mode for controlling the position of the shaft of the motor to the speed control mode.

6. The motor amplifier according to claim 5.

7. The control mode switching is a switching from a torque control mode in which the torque of the shaft of the motor is controlled to the speed control mode.

6. The motor amplifier according to claim 5.

8. A motor control method executed by a motor amplifier that controls rotation of a motor, comprising: obtaining a control value relating to a control mode of the motor; The control value is set even if the acquired control value is for a control mode different from the current control mode, Obtaining a command regarding the control mode of the motor; If the command is a command to switch the control mode, start control with the set control value; Calculating a difference between a current value of the shaft speed of the motor and a set value of the speed, and changing the shaft speed of the motor by complementing the difference value; A speed command is input before the control mode is switched, and Td, which is a specific time during which the speed value is changed, is calculated by the following formula (1). Td=kVd... Formula (1) Here, Td is proportional to the speed difference Vd, and the larger the speed difference, the larger Td is. "k" is a constant that is set according to the load and inertia. A motor control method comprising:

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