Motor Drive Unit

Abstract

This motor drive device drives, on the basis of a command from a controller, a motor for controlling the position of an object and is provided with: a correction command output unit for outputting a correction command for correcting the position of the motor on the basis of the position of the object detected by a displacement sensor for detecting the position of the object; and a position control unit for outputting a drive signal for driving the motor on the basis of the command from the controller and the position of the motor detected by an encoder for detecting the position of the motor or on the basis of the correction command and the position of the motor detected by the encoder.

Description

[Technical field]

[0001] The present disclosure relates to a motor drive device that drives a motor. [Background technology]

[0002] 2. Description of the Related Art Conventionally, there is known a motor driving device that drives a motor that controls the position of an object based on a command from a controller.

[0003] For example, Patent Document 1 describes a motor drive device that drives a motor based on a corrected target position command that is output from a controller and that is a feedback of the sensing result of a sensor that detects the position of an object.

[0004] According to the technology described in Patent Document 1, feedback based on the sensing result is transmitted to the motor drive device via a controller. For this reason, a time lag may occur between the timing of sensing by the sensor and the timing of the feedback being transmitted to the motor drive device. This time lag may cause a decrease in the control accuracy of the target object's position. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] JP 2008-299710 A Summary of the Invention

[0006] In view of the above, an object of the present disclosure is to provide a motor drive device that can suppress a decrease in the control accuracy of the position of an object.

[0007] A motor driving device according to one aspect of the present disclosure is a motor driving device that drives a motor that controls a position of an object based on a command from a controller, and includes a correction command output unit that outputs a correction command to correct a position of the motor based on a position of the object detected by a displacement sensor that detects the position of the object, and a position control unit that outputs a drive signal to drive the motor based on the command from the controller and the position of the motor detected by an encoder that detects the position of the motor, or based on the correction command and the position of the motor detected by the encoder.

[0008] This provides a motor drive device that can suppress a decrease in the accuracy of controlling the position of an object. [Brief description of the drawings]

[0009] [Figure 1] FIG. 1 is a schematic diagram showing a configuration of a sheet winding system according to an embodiment. [Diagram 2] FIG. 2 is a graph showing the relationship between the position of an object detected by the displacement sensor and the voltage in a position signal output from the displacement sensor. [Diagram 3] FIG. 3 is a block diagram illustrating an example of a configuration of a position correction mechanism and a motor drive device according to an embodiment. [Figure 4] FIG. 4 is a graph showing the relationship between the position signal before saturation processing input to the saturation processor and the position signal after saturation processing output from the saturation processor. [Diagram 5] FIG. 5 is a graph showing the relationship between the amount of correction of the object position and the voltage in the correction signal output from the controller. [Figure 6] FIG. 6 is a graph showing the relationship between the correction signal before saturation processing input to the saturation processor and the correction signal after saturation processing output from the saturation processor. [Figure 7] FIG. 7 is a graph showing how the saturation processing section changes the absolute value of the first saturation voltage and the absolute value of the second saturation voltage so as to increase with time. [Figure 8] FIG. 8 is a flowchart of the first operational state change process. [Figure 9] FIG. 9 is a flowchart of the second operating state change process. [Figure 10] FIG. 10 is a flowchart of the third operating state change process. [Figure 11] FIG. 11 is a flowchart of the fourth operating state change process. [Figure 12] FIG. 12 is a flowchart of the fifth operational state change process. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] (How one aspect of the present disclosure was achieved) As described above, according to the technology described in Patent Document 1, the control accuracy of the position of the object may be reduced due to a time lag occurring between the timing of sensing by the sensor and the timing of transmitting feedback to the motor drive device. For this reason, the inventors thought that it would be possible to suppress the reduction in the control accuracy of the position of the object by suppressing this time lag. The inventors conducted extensive experiments and studies on a motor drive device capable of suppressing this time lag. As a result, the inventors came up with the following motor drive device.

[0011] A motor driving device according to one aspect of the present disclosure is a motor driving device that drives a motor that controls a position of an object based on a command from a controller, and includes a correction command output unit that outputs a correction command to correct a position of the motor based on a position of the object detected by a displacement sensor that detects the position of the object, and a position control unit that outputs a drive signal to drive the motor based on the command from the controller and the position of the motor detected by an encoder that detects the position of the motor, or based on the correction command and the position of the motor detected by the encoder.

[0012] According to the motor drive device having the above configuration, the position of the object detected by the displacement sensor can be fed back to the drive signal without going through a controller. Therefore, according to the motor drive device having the above configuration, the time lag is suppressed. Therefore, according to the motor drive device having the above configuration, it is possible to suppress a decrease in the control accuracy of the position of the object.

[0013] In addition, the motor drive device may further include a switching unit that selectively outputs the command from the controller and the correction command, and the position control unit may output the drive signal based on the command or the correction command from the controller selectively output by the switching unit and the position of the motor detected by the encoder.

[0014] This makes it possible to suppress interference between the command from the controller and the correction command.

[0015] In addition, when the switching unit is in a first state in which the command from the controller is selectively output, and a switching signal is input to switch from the first state to a second state in which the correction command is selectively output, the switching unit may switch to the second state after a predetermined period of time has elapsed since the switching signal was input.

[0016] This makes it possible to switch the switching unit from the first state to the second state after waiting for a period during which the operation of the displacement sensor is unstable, such as a period immediately after starting up the displacement sensor, to elapse.

[0017] In addition, when the switching unit is in a first state in which the command from the controller is selectively output, and a switching signal is input to switch from the first state to a second state in which the correction command is selectively output, if the position of the object detected by the displacement sensor is not within a predetermined range, the switching unit may switch to the second state after the position of the object detected by the displacement sensor falls within the predetermined range.

[0018] As a result, when the position of the object detected by the displacement sensor falls within a predetermined range, the switching unit automatically switches from the first state to the second state, which makes it possible to suppress a decrease in the control accuracy of the object position caused by the switching unit not switching from the first state to the second state when the position of the object detected by the displacement sensor falls within the predetermined range.

[0019] In addition, when the switching unit is in a first state in which the command from the controller is selectively output, when a switching signal is input to switch from the first state to a second state in which the correction command is selectively output, the switching unit may be configured to switch to the second state if the position of the object detected by the displacement sensor continues to be within a predetermined range for a predetermined period of time.

[0020] This makes it possible to suppress malfunctions of the motor drive device caused by a phenomenon in which the signal indicating the position of an object detected by the displacement sensor fluctuates instantaneously, such as the occurrence of spike-like noise.

[0021] In addition, when the switching unit is in a first state in which the command from the controller is selectively output, and a switching signal is input to switch from the first state to a second state in which the correction command is selectively output, if the position of the object detected by the displacement sensor is not within a predetermined range after a predetermined period of time has elapsed since the input of the switching signal, the switching unit may switch to the second state after the position of the object detected by the displacement sensor falls within the predetermined range.

[0022] As a result, when the position of the object detected by the displacement sensor falls within a predetermined range after a predetermined period of time has elapsed, the switching unit automatically switches from the first state to the second state. Therefore, when the position of the object detected by the displacement sensor falls within a predetermined range after a predetermined period of time has elapsed, it is possible to suppress a decrease in the control accuracy of the object position due to the switching unit not switching from the first state to the second state.

[0023] In addition, when the switching unit is in a first state in which the command from the controller is selectively output, and a switching signal is input to switch from the first state to a second state in which the correction command is selectively output, the switching unit may be configured to switch to the second state if a state in which the position of the object detected by the displacement sensor remains within a predetermined range for a second predetermined period after a first predetermined period has elapsed since the switching signal was input.

[0024] As a result, if a phenomenon occurs in which the signal indicating the position detected by the displacement sensor momentarily fluctuates after the first specified period has elapsed, such as the occurrence of spike-like noise, it is possible to suppress malfunction of the motor drive device caused by this phenomenon.

[0025] In addition, the motor drive device may further include a saturation processing unit that performs saturation processing on the position of the object detected by the displacement sensor, and the correction command output unit may output the correction command based on the position where the saturation processing is performed.

[0026] This makes it possible to prevent problems caused by the motor being driven suddenly.

[0027] In addition, the saturation processing unit may change the absolute value of the saturation value in the saturation processing so as to increase it over time when a switching signal is input to switch the switching unit from a first state in which the command is selectively output to a second state in which the correction command is selectively output.

[0028] This makes it possible to suppress the occurrence of problems caused by the motor being suddenly driven as a result of the switching unit being switched from the first state to the second state.

[0029] A specific example of a motor control device according to one aspect of the present disclosure will be described below with reference to the drawings. Each embodiment shown here shows one specific example of the present disclosure. Therefore, the numerical values, shapes, components, arrangement and connection of the components, steps (processes) and order of steps shown in the following embodiments are merely examples and are not intended to limit the present disclosure. Furthermore, each figure is a schematic diagram and is not necessarily a precise illustration.

[0030] In addition, a comprehensive or specific aspect of the present disclosure may be realized by a system, a method, an integrated circuit, a computer program, or a recording medium such as a computer-readable CD-ROM (Compact Disc Read only memory), or may be realized by any combination of a system, a method, an integrated circuit, a computer program, and a recording medium.

[0031] (Embodiment) <Configuration> FIG. 1 is a schematic diagram showing a configuration of a sheet winding system 1 according to an embodiment.

[0032] As shown in FIG. 1, the sheet winding system 1 includes a motor drive device 10, a controller 20, a position correction mechanism 30, a displacement sensor 40, a winder 50, an object 60 (here, a sheet 60), and an input device 70.

[0033] The winder 50 winds up the object 60, that is, the sheet 60. Here, the winder 50 winds up the sheet 60 in the longitudinal direction (the x-axis direction shown in FIG. 1).

[0034] The displacement sensor 40 detects the position of the target object 60. Here, the displacement sensor 40 detects the position in the short-side direction of the sheet 60 (the y-axis direction shown in FIG. 1). More specifically, the displacement sensor 40 is a sensor (laser displacement sensor) that detects the position of the end portion of the sheet 60 in the y-axis direction shown in FIG. 1 by irradiating a laser beam near the end portion of the sheet 60 in the y-axis direction shown in FIG. 1 and receiving at least one of the laser beam reflected by the sheet 60 and the laser beam not reflected by the sheet 60.

[0035] When the displacement sensor 40 detects the position of the object 60, it outputs a position signal indicating the detected position.

[0036] FIG. 2 is a graph showing the relationship between the position of the object 60 detected by the displacement sensor 40 and the voltage in the position signal output from the displacement sensor 40.

[0037] In FIG. 2, the horizontal axis represents the difference Δy1 between the position of the object 60 detected by the displacement sensor 40 and a reference position, and the vertical axis represents the voltage of the position signal.

[0038] As shown in FIG. 2, the displacement sensor 40 outputs a position signal that is a voltage proportional to a difference Δy1 between the position of the object 60 detected by the displacement sensor 40 and a reference position.

[0039] Returning to FIG. 1, the explanation of the sheet winding system 1 will be continued.

[0040] The position correction mechanism 30 includes a motor and controls the position of the object 60. Here, the position correction mechanism 30 controls the position of the sheet 60 in the y-axis direction shown in FIG.

[0041] As the winder 50 winds up the sheet 60, the position of the sheet 60 in the y-axis direction shown in Fig. 1 may shift from a desired reference position. Such a shift occurs, for example, when the thickness of the sheet 60 is non-uniform, when the rollers constituting the winder 50 are worn, etc.

[0042] The position correction mechanism 30 is a mechanism for correcting such a deviation and returning the position of the sheet 60 in the y-axis direction shown in FIG. 1 to a desired reference position.

[0043] The motor drive device 10 drives a motor included in a position correction mechanism 30 based on a position command from a controller 20 .

[0044] FIG. 3 is a block diagram showing an example of the configuration of the position correction mechanism 30 and the motor drive device 10 according to the embodiment.

[0045] As shown in FIG. 3, the position correction mechanism 30 includes a motor 31 and an encoder 32.

[0046] The motor 31 controls the position of the object 60. Here, the motor 31 controls the position of the seat 60 in the y-axis direction shown in Fig. 1. The motor 31 is driven by a drive signal (described later) output from the motor drive device 10. The motor 31 may be, for example, a rotary motor or a linear motor such as a linear motor.

[0047] The encoder 32 detects the position of the motor 31. If the motor 31 is a rotary motor, the encoder 32 detects, for example, the rotation angle of the rotary shaft of the motor 31. If the motor 31 is a linear motor, the encoder 32 detects, for example, the position of the mover of the motor 31.

[0048] When the encoder 32 detects the position of the motor 31, it outputs an encoded signal indicating the detected position.

[0049] As shown in FIG. 3, motor drive device 10 includes a position control unit 11, a correction command output unit 12, a switching unit 13, and a saturation processing unit .

[0050] The saturation processing unit 14 receives the position signal output from the displacement sensor 40, a correction signal output from the controller 20 indicating the amount of correction for the position of the object 60, and a switching signal (described later) output from the controller 20, and (1) performs saturation processing on the position of the object 60 indicated by the position signal or the corrected position of the object 60 indicated by the correction signal, and outputs the position signal after saturation processing or the correction signal after saturation processing, or (2) outputs the input position signal or the input correction signal as is without performing saturation processing.

[0051] The saturation processor 14 includes, for example, a processor (not shown) and a memory (not shown). The processor may execute a program stored in the memory to realize various functions.

[0052] FIG. 4 is a graph showing the relationship between the position signal before saturation processing input to the saturation processor 14 and the position signal after saturation processing output from the saturation processor 14. As shown in FIG.

[0053] 4, the horizontal axis represents the voltage of the position signal before saturation processing, and the vertical axis represents the voltage of the position signal after saturation processing.

[0054] As shown in FIG. 4, saturation processor 14 performs saturation processing so that the maximum voltage of the output position signal after saturation processing becomes a first saturation voltage and the minimum voltage becomes a second saturation voltage.

[0055] FIG. 5 is a graph showing the relationship between the amount of correction of the position of the object 60 and the voltage in the correction signal output from the controller 20. As shown in FIG.

[0056] In FIG. 5, the horizontal axis represents the correction amount Δy2 of the position of the object 60, and the vertical axis represents the voltage of the analog correction signal.

[0057] As shown in FIG. 5, the controller 20 outputs a correction signal that becomes a voltage proportional to a correction amount Δy2 of the position of the target object 60.

[0058] FIG. 6 is a graph showing the relationship between the correction signal before saturation processing input to the saturation processor 14 and the correction signal after saturation processing output from the saturation processor 14. As shown in FIG.

[0059] In FIG. 6, the horizontal axis represents the voltage of the correction signal before saturation processing, and the vertical axis represents the voltage of the correction signal after saturation processing.

[0060] As shown in FIG. 6, the saturation processor 14 performs saturation processing so that the maximum voltage of the output post-saturation processing correction signal becomes the first saturation voltage and the minimum voltage becomes the second saturation voltage.

[0061] When a switching signal is input from the controller 20, the saturation processor 14 has a function of changing the absolute value of the first saturation voltage and the absolute value of the second saturation voltage so that they increase with time.

[0062] FIG. 7 is a graph showing how the saturation processor 14 changes the absolute value of the first saturation voltage and the absolute value of the second saturation voltage so as to increase with time.

[0063] In FIG. 7, the horizontal axis represents time, with the time when the switching signal is input being designated as time 0, and the vertical axis represents the voltages of the first saturation voltage and the second saturation voltage.

[0064] 7, the saturation processor 14 changes the first saturation voltage so that its absolute value increases linearly with time, such that the voltage is 0 at time 0 and the voltage is Vmax at time t1. The saturation processor 14 also changes the second saturation voltage so that its absolute value increases linearly with time, such that the voltage is 0 at time 0 and the voltage is Vmin at time t1.

[0065] Returning to FIG. 3, the description of motor driving device 10 will continue.

[0066] The correction command output unit 12 receives the position signal or correction signal output from the saturation processing unit 14, and outputs a correction position command that commands the correction position of the motor 31 based on the position of the object 60 detected by the displacement sensor 40, which is indicated by the position signal, or the correction amount of the position of the object 60, which is indicated by the correction signal.

[0067] Here, as described above, the position signal output from the displacement sensor 40 is input to the correction command output unit 12 via the saturation processing unit 14, i.e., without passing through the controller 20. Therefore, the position of the object 60 detected by the displacement sensor 40 is fed back to a drive signal (described later) for driving the motor 31, without passing through the controller 20.

[0068] The correction command output unit 12 may include, for example, a processor (not shown) and a memory (not shown), and the various functions may be realized by the processor executing a program stored in the memory.

[0069] The switching unit 13 receives a position command output from the controller 20 for commanding the position of the motor 31, a corrected position command output from the correction command output unit 12, a switching signal output from the controller 20, and a position signal output from the displacement sensor 40, and selectively outputs the position command and the corrected position command. Here, the switching signal is a signal that switches the state of the switching unit 13, and more specifically, is a signal that switches between a first state in which the position command is selectively output, and a second state in which the corrected position command is selectively output.

[0070] When the switching unit 13 is in the first state, the motor driving device 10 is in a state where it drives the motor 31 based on a position command output from the controller 20. When the switching unit 13 is in the second state, the motor driving device 10 is in a state where it drives the motor 31 based on a position signal output from the displacement sensor 40 or a correction signal output from the controller 20. When the switching unit 13 is in the second state, the position command output from the controller 20 is fixed.

[0071] The switching unit 13 may include, for example, a processor (not shown) and a memory (not shown), and the various functions may be realized by the processor executing a program stored in the memory.

[0072] The switching unit 13 has the following first to fifth functions.

[0073] The first function is a function of switching to the second state after a predetermined period has elapsed since the switching signal is input when the switching unit 13 is in the first state and a switching signal for switching from the first state to the second state is input. The first function is a function that is realized when the switching unit 13 is set to the first operation mode.

[0074] The second function is a function of switching to the second state after the position of the object 60 indicated by the position signal or the correction amount of the object 60 indicated by the correction signal falls within a predetermined range when a switching signal for switching from the first state to the second state is input while the switching unit 13 is in the first state. The second function is a function that is realized when the switching unit 13 is set to the second operation mode.

[0075] Here, whether the position of the object 60 indicated by the position signal or the correction amount of the object 60 indicated by the correction signal is within a predetermined range may be determined, for example, by checking whether the voltage of the position signal or the correction signal is equal to or greater than a predetermined value. For example, it may be determined by checking whether the voltage of the position signal or the correction signal is equal to or less than a predetermined value. It may also be determined by checking whether the voltage of the position signal or the correction signal is equal to or greater than a first predetermined value and equal to or less than a second predetermined value that is greater than the first predetermined value. It may also be determined by checking whether the voltage of the position signal or the correction signal is equal to or less than a first predetermined value, or equal to or greater than a second predetermined value that is greater than the first predetermined value.

[0076] The third function is a function of switching to the second state when a switching signal for switching from the first state to the second state is input while the switching unit 13 is in the first state and the position of the object 60 indicated by the position signal continues to be within a predetermined range for a predetermined period of time. The third function is a function that is realized when the switching unit 13 is set to the third operation mode.

[0077] The fourth function is a function of switching to the second state when the switching unit 13 is in the first state and a switching signal for switching from the first state to the second state is input, if the position of the object 60 indicated by the position signal is not within a predetermined range at a time point when a predetermined period has elapsed since the input of the switching signal, switching to the second state after the position of the object 60 indicated by the position signal falls within the predetermined range. The fourth function is a function that is realized when the switching unit 13 is set to the fourth operation mode.

[0078] The fifth function is a function of switching to the second state when a switching signal for switching from the first state to the second state is input while the switching unit 13 is in the first state, if the position of the object 60 indicated by the position signal continues to be within a predetermined range for a predetermined period after a first predetermined period has elapsed since the input of the switching signal, the fifth function is a function that is realized when the switching unit 13 is set to the fifth operation mode.

[0079] The position control unit 11 receives a position command or a correction command selectively output from the switching unit 13 and an encoded signal output from the encoder 32, and outputs a drive signal for driving the motor 31 based on the position command and the position of the motor 31 indicated by the encoded signal, or based on the corrected position command and the position of the motor 31 indicated by the encoded signal. Here, the drive signal is a current passed through the motor 31 to drive the motor 31.

[0080] Position control unit 11 may include, for example, a processor (not shown) and a memory (not shown), and the various functions may be realized by the processor executing a program stored in the memory.

[0081] Returning to FIG. 1, the explanation of the sheet winding system 1 will be continued.

[0082] The input device 70 receives an input of an operation command for the sheet winding system 1 from a user who uses the sheet winding system 1. Then, the input device 70 outputs the received operation command to the controller 20.

[0083] The input device 70 may have various functions realized by, for example, a personal computer having an input / output device.

[0084] The controller 20 receives an operation command from the input device 70, and generates a position command, a switching signal, and a correction signal based on the operation command. The controller 20 outputs the generated position command, switching signal, and correction signal to the motor drive device 10.

[0085] The controller 20 may include, for example, a processor (not shown) and a memory (not shown), and various functions may be realized by the processor executing a program stored in the memory.

[0086] <Operation> The operation of the motor driving device 10 configured as above will now be described.

[0087] The motor driving device 10 can perform a first operating state change process to a fifth operating state change process, which change the operating state from a state in which the motor 31 is driven based on a position command output from the controller 20 to a state in which the motor 31 is driven based on a position signal output from the displacement sensor 40 or a correction signal output from the controller 20.

[0088] First, the first operational state change process will be described.

[0089] FIG. 8 is a flowchart of the first operational state change process.

[0090] The first operating state change process is initiated, for example, when, with the switching unit 13 set to the first operating mode, a switching signal output from the controller 20 to the switching unit 13 indicating that the state of the switching unit 13 is to be switched from the first state to the second state is input to the switching unit 13.

[0091] When the first motor driving process is started, the switching unit 13 checks whether or not its own state is the first state (step S10).

[0092] In the process of step S10, if the state of the motor driving device 10 itself is the first state (step S10: Yes), the switching unit 13 waits until a predetermined period of time has elapsed since the switching signal was input (step S20: No is repeated). When the predetermined period of time has elapsed (step S20: Yes), the switching unit 13 switches its state from the first state to the second state (step S30). As a result, the operating state of the motor driving device 10 is changed from a state in which the motor 31 is driven based on a position command output from the controller 20 to a state in which the motor 31 is driven based on a position signal output from the displacement sensor 40 or a correction signal output from the controller 20.

[0093] When the motor driving device 10 is not in the first state in the process of step S10 (step S10: No) or when the process of step S30 ends, the motor driving device 10 ends the first operating state change process.

[0094] FIG. 9 is a flowchart of the second operating state change process.

[0095] The second operating state change process is initiated, for example, when the switching unit 13 is set to the second operating mode and a switching signal output from the controller 20 to switch the state of the switching unit 13 from the first state to the second state is input to the switching unit 13.

[0096] When the second motor driving process is started, the switching unit 13 checks whether its own state is the first state (step S110).

[0097] In the process of step S110, if the switching unit 13's own state is the first state (step S110: Yes), the switching unit 13 checks whether the position of the target object 60 indicated by the position signal is within a predetermined range (step S120).

[0098] In the process of step S120, if the position of the object 60 is not within the predetermined range (step S120: No), the switching unit 13 waits until the position of the object 60 is within the predetermined range (step S120: No is repeated).

[0099] In the process of step S120, if the position of the target object 60 is within a predetermined range (step S120: Yes), the switching unit 13 switches its own state from the first state to the second state (step S130). As a result, the operation state of the motor driving device 10 is changed from a state in which the motor 31 is driven based on a position command output from the controller 20 to a state in which the motor 31 is driven based on a position signal output from the displacement sensor 40 or a correction signal output from the controller 20.

[0100] When the motor driving device 10 is not in the first state in the process of step S110 (step S110: No) and when the process of step S130 ends, the motor driving device 10 ends the second operating state change process.

[0101] FIG. 10 is a flowchart of the third operating state change process.

[0102] The third operating state change process is initiated, for example, when the switching unit 13 is set to the third operating mode and a switching signal output from the controller 20 to switch the state of the switching unit 13 from the first state to the second state is input to the switching unit 13.

[0103] When the third motor driving process is started, the switching unit 13 checks whether its own state is the first state (step S210).

[0104] In the process of step S210, if the state of the motor driving device 10 itself is the first state (step S210: Yes), the switching unit 13 waits until the state in which the position of the object 60 indicated by the position signal is within a predetermined range continues for a predetermined period (step S220: No is repeated). If the state in which the position of the object 60 indicated by the position signal is within a predetermined range continues for a predetermined period (step S220: Yes), the switching unit 13 switches its state from the first state to the second state (step S230). As a result, the operation state of the motor driving device 10 is changed from a state in which the motor 31 is driven based on a position command output from the controller 20 to a state in which the motor 31 is driven based on a position signal output from the displacement sensor 40 or a correction signal output from the controller 20.

[0105] When the motor driving device 10 is not in the first state in the process of step S210 (step S210: No) or when the process of step S230 ends, the motor driving device 10 ends the third operating state change process.

[0106] FIG. 11 is a flowchart of the fourth operating state change process.

[0107] The fourth operating state change process is initiated, for example, when the switching unit 13 is set to the fourth operating mode and a switching signal output from the controller 20 to switch the state of the switching unit 13 from the first state to the second state is input to the switching unit 13.

[0108] When the fourth motor driving process is started, the switching unit 13 checks whether its own state is the first state (step S310).

[0109] In the process of step S310, if the switching unit 13 is in the first state (step S310: Yes), the switching unit 13 waits until a predetermined period of time has elapsed since the switching signal was input (step S320: Yes is repeated). When the predetermined period of time has elapsed (step S320: No), the switching unit 13 checks whether the position of the target object 60 indicated by the position signal is within a predetermined range (step S330).

[0110] In the process of step S330, if the position of the object 60 is not within the predetermined range (step S330: No), the switching unit 13 waits until the position of the object 60 is within the predetermined range (step S330: No is repeated).

[0111] In the process of step S330, if the position of the target object 60 is within a predetermined range (step S330: Yes), the switching unit 13 switches its own state from the first state to the second state (step S340). As a result, the operation state of the motor driving device 10 is changed from a state in which the motor 31 is driven based on the position command output from the controller 20 to a state in which the motor 31 is driven based on the position signal output from the displacement sensor 40 or the correction signal output from the controller 20.

[0112] When the motor driving device 10 is not in the first state in the process of step S310 (step S310: No) or when the process of step S340 ends, the motor driving device 10 ends the fourth operating state change process.

[0113] FIG. 12 is a flowchart of the fifth operational state change process.

[0114] The fifth operating state change process is initiated, for example, when, with the switching unit 13 set to the fifth operating mode, a switching signal output from the controller 20 to switch the state of the switching unit 13 from the first state to the second state is input to the switching unit 13.

[0115] When the fifth motor driving process is started, the switching unit 13 checks whether its own state is the first state (step S410).

[0116] In the process of step S410, if the state of the switching unit 13 itself is the first state (step S410: Yes), the switching unit 13 waits until a predetermined period has elapsed since the switching signal was input (step S420: Yes is repeated). When the predetermined period has elapsed (step S420: No), the switching unit 13 waits until the state in which the position of the object 60 indicated by the position signal is within a predetermined range continues for a predetermined period (step S430: No is repeated). When the state in which the position of the object 60 indicated by the position signal is within a predetermined range continues for a predetermined period (step S430: Yes), the switching unit 13 switches its state from the first state to the second state (step S440). As a result, the operation state of the motor driving device 10 is changed from a state in which the motor 31 is driven based on the position command output from the controller 20 to a state in which the motor 31 is driven based on the position signal output from the displacement sensor 40 or the correction signal output from the controller 20.

[0117] When the motor driving device 10 is not in the first state in the process of step S410 (step S410: No) or when the process of step S440 ends, the motor driving device 10 ends the fifth operating state change process.

[0118] <Consideration> According to the motor drive device 10, the position of the object 60 detected by the displacement sensor 40 can be fed back to the drive signal without going through the controller 20. This reduces the time lag between the timing of sensing by the sensor and the timing of the feedback being transmitted to the motor drive device, which occurs in the technology described in Patent Document 1. Therefore, according to the motor drive device 10, it is possible to prevent a decrease in the control accuracy of the position of the object 60.

[0119] In the motor drive device 10, the switching unit 13 selectively outputs the position command and the corrected position command, thereby making it possible to suppress interference between the position command and the corrected position command.

[0120] According to the motor drive device 10, when the switching unit 13 is in the first state and a switching signal for switching from the first state to the second state is input, the switching unit 13 can switch to the second state after a predetermined time has elapsed since the switching signal was input. Therefore, the switching unit 13 can switch from the first state to the second state after waiting for a period during which the operation of the displacement sensor 40 is unstable, such as a period immediately after the displacement sensor 40 is started.

[0121] According to the motor drive device 10, when the switching unit 13 is in the first state, if the position of the object 60 detected by the displacement sensor 40 is not within a predetermined range when a switching signal for switching from the first state to the second state is input, the switching unit 13 can switch to the second state after the position of the object 60 detected by the displacement sensor 40 falls within the predetermined range. Therefore, when the position of the object 60 detected by the displacement sensor 40 falls within the predetermined range, the switching unit 13 automatically switches from the first state to the second state. Therefore, when the position of the object 60 detected by the displacement sensor 40 falls within the predetermined range, it is possible to suppress a decrease in the control accuracy of the position of the object 60 caused by the switching unit 13 not switching from the first state to the second state.

[0122] According to the motor drive device 10, when a switching signal for switching from the first state to the second state is input, the switching unit 13 can switch to the second state if the position of the object 60 detected by the displacement sensor 40 continues to be within a predetermined range for a predetermined period of time in the first state. Therefore, when a phenomenon occurs in which the signal indicating the position of the object 60 detected by the displacement sensor 40 momentarily fluctuates, for example, when a spike-like noise is carried over, a malfunction of the motor drive device 10 caused by this phenomenon can be suppressed.

[0123] According to the motor drive device 10, when the switching unit 13 is in the first state, if a switching signal for switching from the first state to the second state is input, and if the position of the object 60 detected by the displacement sensor 40 is not within a predetermined range at a time point when a predetermined time has elapsed since the switching signal was input, the switching unit 13 can switch to the second state after the position of the object 60 detected by the displacement sensor 40 falls within the predetermined range. Therefore, when the position of the object 60 detected by the displacement sensor 40 falls within the predetermined range after a predetermined time has elapsed, the switching unit 13 automatically switches from the first state to the second state. Therefore, when the position of the object 60 detected by the displacement sensor 40 falls within the predetermined range after a predetermined time has elapsed, it is possible to suppress a decrease in the control accuracy of the position of the object 60 due to the switching unit 13 not switching from the first state to the second state.

[0124] According to the motor drive device 10, when a switching signal for switching from the first state to the second state is input, the switching unit 13 can switch to the second state if the state in which the position of the object 60 detected by the displacement sensor 40 remains within a predetermined range for a second predetermined period after the first period has elapsed since the switching signal was input. Therefore, when a phenomenon occurs in which the signal indicating the position of the object 60 detected by the displacement sensor 40 momentarily fluctuates after the first predetermined period has elapsed, such as a phenomenon in which spike-like noise is carried over, a malfunction of the motor drive device 10 caused by this phenomenon can be suppressed.

[0125] According to the motor drive device 10, the saturation processor 14 performs saturation processing on the position of the target object 60 detected by the displacement sensor 40, and the correction command output unit 12 can output the second drive signal based on the position where the saturation processing has been performed. This makes it possible to prevent problems caused by the motor 31 being driven suddenly.

[0126] According to the motor drive device 10, when a switching signal for switching the switching unit 13 from the first state to the second state is input, the saturation processing unit 14 can change the absolute value of the saturation value in the saturation processing so as to increase it over time. This makes it possible to suppress the occurrence of problems caused by the motor 31 being suddenly driven as a result of the switching unit 13 being switched from the first state to the second state.

[0127] (Other embodiments) As described above, the embodiments have been described as examples of the technology disclosed in this application. However, the technology according to this disclosure is not limited to these, and can be applied to embodiments or modified examples in which changes, substitutions, additions, omissions, etc. are appropriately made without departing from the spirit of this disclosure.

[0128] (1) In the embodiment, the object 60 has been described as being a sheet as an example of the object 60. However, the object 60 may be any object as long as the position of the object 60 can be controlled by the motor 31, and is not necessarily limited to the example of a sheet.

[0129] (2) In the embodiment, the command output from the controller 20 to the motor drive device 10 is described as a position command commanding the position of the motor 31. However, the command output from the controller 20 to the motor drive device 10 is not necessarily limited to the example of a position command, so long as it is a command for driving the motor 31. For example, the command output from the controller 20 to the motor drive device 10 may be a speed command commanding the speed of the motor 31. In this case, the position control unit 11 outputs a drive signal for driving the motor 31 based on the speed command and the position of the motor 31 indicated by the encoded signal. For example, the command output from the controller 20 to the motor drive device 10 may be a torque command commanding the acceleration of the motor 31. In this case, the position control unit 11 outputs a drive signal for driving the motor 31 based on the torque command and the position of the motor 31 indicated by the encoded signal.

[0130] (3) In the embodiment, the command output by the correction command output unit 12 has been described as a correction position command that commands a correction position of the motor 31. However, the command output by the correction command output unit 12 is not necessarily limited to the example of a correction position command, as long as it is a command for driving the motor 31. For example, the command output by the correction command output unit 12 may be a correction speed command that commands the speed of the motor 31. In this case, the position control unit 11 outputs a drive signal for driving the motor 31 based on the correction speed command and the position of the motor 31 indicated by the encoded signal. For example, the command output by the correction command output unit 12 may be a correction torque command that commands the acceleration of the motor 31. In this case, the position control unit 11 outputs a drive signal for driving the motor 31 based on the correction torque command and the position of the motor 31 indicated by the encoded signal.

[0131] (4) In the embodiment, the displacement sensor 40 has been described as a laser displacement sensor that detects the position of the object 60 by receiving laser light. However, the displacement sensor 40 does not necessarily need to be limited to the example of a laser displacement sensor as long as it can detect the position of the object 60. For example, the displacement sensor 40 may be a pressure displacement sensor that detects the position of the object 60 by detecting pressure. For example, the displacement sensor 40 may be a temperature displacement sensor that detects the position of the object 60 by detecting temperature. Or it may be an acceleration displacement sensor that detects the position of the object 60 by detecting acceleration.

[0132] (5) In the embodiment, it has been described that when switching unit 13 is in the second state, the position command sent from controller 20 to switching unit 13 is fixed. However, in this case, the position command sent from controller 20 to switching unit 13 does not necessarily have to be fixed, and may not be fixed. [Industrial Applicability]

[0133] The present disclosure is widely applicable to motor driving devices that drive motors. [Explanation of symbols]

[0134] 1 Sheet winding system 10 Motor drive device 11 Position control section 12 Correction command output section 13 Switching section 14 Saturation Processing Section 20 Controller 30 Position correction mechanism 31 Motor 32 Encoder 40 Displacement Sensor 50 Winder 60 Object (sheet) 70 Input Device

Claims

1. A motor drive device that drives a motor that controls a position of an object based on a command from a controller, a correction command output unit that outputs a correction command for correcting a position of the motor based on a position of the object detected by a displacement sensor that detects the position of the object; a position control unit that outputs a drive signal for driving the motor based on the command from the controller and a position of the motor detected by an encoder that detects the position of the motor, or based on the correction command and the position of the motor detected by the encoder; a switching unit that selectively outputs the command from the controller and the correction command, the position control unit outputs the drive signal based on the command or the correction command selectively output from the switching unit and the position of the motor detected by the encoder; when a switching signal is inputted to the switching unit in a first state in which the command from the controller is selectively outputted, the switching unit switches to the second state after a predetermined period has elapsed since the input of the switching signal, indicative of switching from the first state to a second state in which the correction command is selectively outputted. Motor drive device.

2. A motor drive device that drives a motor that controls the position of an object based on a command from a controller, comprising: a correction command output unit that outputs a correction command for correcting a position of the motor based on a position of the object detected by a displacement sensor that detects the position of the object; a position control unit that outputs a drive signal for driving the motor based on the command from the controller and a position of the motor detected by an encoder that detects the position of the motor, or based on the correction command and the position of the motor detected by the encoder; a switching unit that selectively outputs the command from the controller and the correction command, the position control unit outputs the drive signal based on the command or the correction command selectively output from the switching unit and the position of the motor detected by the encoder; a switching unit configured to switch from the first state in which the command from the controller is selectively output to a second state in which the correction command is selectively output, and when a switching signal is input to switch from the first state to a second state in which the correction command is selectively output, if the position of the object detected by the displacement sensor is not within a predetermined range, the switching unit switches to the second state after the position of the object detected by the displacement sensor falls within the predetermined range.

3. A motor drive device that drives a motor that controls the position of an object based on a command from a controller, comprising: a correction command output unit that outputs a correction command for correcting a position of the motor based on a position of the object detected by a displacement sensor that detects the position of the object; a position control unit that outputs a drive signal for driving the motor based on the command from the controller and a position of the motor detected by an encoder that detects the position of the motor, or based on the correction command and the position of the motor detected by the encoder; a switching unit that selectively outputs the command from the controller and the correction command, the position control unit outputs the drive signal based on the command or the correction command selectively output from the switching unit and the position of the motor detected by the encoder; when a switching signal is input to the switching unit in a first state in which the command from the controller is selectively outputted, to switch from the first state to a second state in which the correction command is selectively outputted, if a state in which the position of the object detected by the displacement sensor remains within a predetermined range for a predetermined period of time, the switching unit switches to the second state. Motor drive device.

4. A motor drive device that drives a motor that controls the position of an object based on a command from a controller, comprising: a correction command output unit that outputs a correction command for correcting a position of the motor based on a position of the object detected by a displacement sensor that detects the position of the object; a position control unit that outputs a drive signal for driving the motor based on the command from the controller and a position of the motor detected by an encoder that detects the position of the motor, or based on the correction command and the position of the motor detected by the encoder; a switching unit that selectively outputs the command from the controller and the correction command, the position control unit outputs the drive signal based on the command or the correction command selectively output from the switching unit and the position of the motor detected by the encoder; when a switching signal is input to switch from the first state to a second state in which the command from the controller is selectively output, if a position of the object detected by the displacement sensor is not within a predetermined range at a time point when a predetermined period has elapsed since the input of the switching signal, the switching unit switches to the second state after the position of the object detected by the displacement sensor falls within the predetermined range. Motor drive device.

5. A motor drive device that drives a motor that controls the position of an object based on a command from a controller, comprising: a correction command output unit that outputs a correction command for correcting a position of the motor based on a position of the object detected by a displacement sensor that detects the position of the object; a position control unit that outputs a drive signal for driving the motor based on the command from the controller and a position of the motor detected by an encoder that detects the position of the motor, or based on the correction command and the position of the motor detected by the encoder; a switching unit that selectively outputs the command from the controller and the correction command, the position control unit outputs the drive signal based on the command or the correction command selectively output from the switching unit and the position of the motor detected by the encoder; when a switching signal is input to the switching unit in a first state in which the command from the controller is selectively output, the switching unit switches to the second state if a state in which the position of the object detected by the displacement sensor remains within a predetermined range for a second predetermined period after a first predetermined period has elapsed since the input of the switching signal. The motor drive device according to claim 2 .

6. Further, a saturation processing unit that performs saturation processing on the position of the object detected by the displacement sensor, the correction command output unit outputs the correction command based on a position where the saturation process is performed. The motor drive device according to any one of claims 1 to 5.

7. The saturation processing unit changes an absolute value of the saturation value in the saturation processing so as to increase over time when a switching signal is input to switch the switching unit from a first state in which the command from the controller is selectively output to a second state in which the correction command is selectively output. The motor drive device according to claim 6.

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