JP7585686B2 - Control device and control method - Google Patents

Description

This disclosure relates to a control device and a control method.

Technologies are being researched to suppress the effects of load fluctuations and control motors with high precision. For example, a method of controlling a motor in an inkjet printer is known in which the motor is controlled to micro-feed the carriage carrying the print head, thereby achieving an appropriate capping operation for the print head (see, for example, Patent Document 1).

In this control method, the drive current applied to the motor is gradually increased from an initial value, and when it is detected that the carriage has moved based on the encoder signal, the drive current is returned to the initial value, and this operation is repeated. Furthermore, the rate at which the drive current is increased is changed in response to load fluctuations.

JP 2006-25497 A

When a motor is used to drive a driven object, if the load fluctuation on the motor due to the displacement of the driven object is large, the driving force of the motor may be insufficient, causing the driven object to stop. When this occurs, it is necessary to generate a motor torque that overcomes static friction in order to displace the driven object again, which can easily lead to unstable control.

Therefore, according to one aspect of the present disclosure, it is desirable to provide a control device and control method that can appropriately control the displacement of a moving part while suppressing the effects of load fluctuations.

A control device according to one aspect of the present disclosure includes a motor, a movable part, and a controller. The movable part is configured to be displaced by receiving power from the motor. The controller is configured to control the motor.

The controller executes a control process and a correction process. In the control process, the controller calculates the amount of operation for the motor, and controls the motor by inputting power corresponding to the amount of operation to the motor. In the correction process, the controller corrects the amount of operation.

According to one aspect of the present disclosure, in the control process, when the operation amount is corrected by the correction process, the controller controls the motor by inputting power corresponding to the corrected operation amount to the motor.

According to one aspect of the present disclosure, in the correction process, the controller performs a correction to increase the operation amount when it is estimated that the moving part is displaced toward the peak position in a section upstream in the displacement direction of the moving part from a peak position, which is the position of the moving part where the load acting on the motor is estimated to reach its peak, and in a section where the load is estimated to rise toward the peak.

By increasing the amount of operation in the above section, it is possible to prevent the moving part from being overwhelmed by the load and stopping or retreating as the moving part displaces toward the peak of the load. Therefore, according to one aspect of the present disclosure, it is possible to provide a control device that can appropriately control the displacement of the moving part even in an environment where the load changes.

According to one aspect of the present disclosure, in the control process, the controller may calculate the manipulated variable so that each time the movable part is displaced a predetermined amount downstream in the displacement direction, the manipulated variable is lowered to an initial value, and then the manipulated variable is gradually increased from the initial value. In the correction process, the controller may correct the manipulated variable by correcting the initial value so as to increase it. Such a correction can prevent the movable part from being overwhelmed by the load and stopping or retreating in the control that gradually displaces the movable part.

According to one aspect of the present disclosure, in the correction process, the controller may correct the manipulated variable by adding a predetermined correction amount to the manipulated variable. Such a correction makes it possible to realize appropriate motor control according to the load without complex correction.

According to one aspect of the present disclosure, in the correction process, the controller may correct the manipulated variable by adding a correction amount corresponding to the deviation between the target speed and the speed of the moving part detected by the detector to the manipulated variable. Such a correction allows the manipulated variable to be corrected using a feedback control method, making it possible to realize appropriate motor control corresponding to the movement of the moving part relative to the load.

According to one aspect of the present disclosure, in the correction process, the controller may set a target speed based on the speed of the movable part when entering the section detected by the detector. In this case, a target speed that matches the movement of the movable part can be set, and an appropriate correction of the manipulated variable can be performed.

According to one aspect of the present disclosure, the controller may set the target speed to a target speed that increases as the moving part displaces in the section. With such a setting, momentum can be imparted to the moving part as it displaces toward the peak position, reducing the possibility that the moving part will be overcome by the load.

According to one aspect of the present disclosure, the controller may further execute a section setting process that sets the above section based on a change in load estimated from observed data of the operation amount for the motor obtained by feedback control of the displacement of the moving part. This process allows the operation amount to be corrected in an appropriate section.

According to one aspect of the present disclosure, the controller may further execute a section setting process that sets the above section based on an abnormal stop position of the moving part when the moving part abnormally stops during the process of controlling the displacement of the moving part by the motor.

According to one aspect of the present disclosure, a method for controlling a motor may be provided. The motor to be controlled may be a motor of a device including a motor and a movable part configured to be displaced by receiving power from the motor.

According to one aspect of the present disclosure, a method for controlling a motor may include calculating an operation amount for the motor, controlling the motor by inputting power corresponding to the operation amount to the motor, and correcting the operation amount.

The controlling may include controlling the motor by inputting power corresponding to the corrected manipulated variable to the motor when the manipulated variable is corrected. The correcting may include correcting to increase the manipulated variable when the movable part is estimated to be displaced toward the peak position in a section upstream in the displacement direction of the movable part from a peak position, which is the position of the movable part where the load acting on the motor is estimated to reach its peak, and in a section where the load is estimated to rise toward the peak.

This motor control method allows the displacement of moving parts to be appropriately controlled even in an environment where the load changes.

FIG. 1 is a block diagram illustrating a configuration of an image forming apparatus. 2 is a diagram illustrating the configuration of a carriage transport mechanism and a paper transport mechanism. FIG. 2 is a functional block diagram of a motor controller according to the first embodiment. 5 is a graph illustrating the on/off state of correction control and changes in a correction amount in the first embodiment. 4 is a flowchart showing a control process executed by a motor controller in the first embodiment. 10 is a flowchart showing a control process executed by a motor controller in a second embodiment. 10 is a graph illustrating the on/off of correction control and changes in a target speed used in the correction control in the second embodiment. FIG. 13 is a functional block diagram of a motor controller according to a third embodiment. 13 is a flowchart showing a section setting process executed by a motor controller in a third embodiment. 11 is a graph illustrating a change in an operation amount in constant speed transport control. 6 is a graph illustrating a method for setting a correction interval based on load data and an on/off state of correction control. FIG. 12A is a diagram for explaining the arrangement of the capping mechanism, and FIG. 12B is a diagram for explaining the configuration of the capping mechanism related to lifting up the cap. 13 is a flowchart showing a minute transport control process executed by a motor controller in the fourth embodiment. 11 is a graph illustrating a change in the amount of operation due to minute transport control together with a change in the position of the carriage. 13 is a flowchart showing a section setting process executed by a motor controller according to a modified example.

Exemplary embodiments of the present disclosure will now be described with reference to the drawings.
[First embodiment]
1 is configured as an inkjet printer, and includes a main controller 10, a communication interface 20, a print controller 30, and a transport controller 40.

The main controller 10 controls the image forming system 1. When the main controller 10 receives image data to be printed from an external device via the communication interface 20, it inputs commands to the print controller 30 and the transport controller 40 so that an image based on the received image data is formed on the paper Q.

The image forming system 1 further includes a recording head 50, an ink tank 51, a head drive circuit 55, a carriage transport mechanism 60, a CR motor 71, a motor drive circuit 73, an encoder 75, and a signal processing circuit 77. The carriage transport mechanism 60 includes a carriage 61 that carries the recording head 50.

The print controller 30 controls the CR motor 71 in accordance with instructions from the main controller 10, thereby controlling the carriage 61 transported by the carriage transport mechanism 60, and further controlling the ink ejection operation of the recording head 50. Through this control, the print controller 30 forms the image on the paper Q.

The recording head 50 is an inkjet head that ejects ink toward the paper Q. The recording head 50 is connected to an ink tank 51, which is not mounted on the carriage 61, via a tube (not shown), and ejects ink by receiving ink supply from the ink tank 51 via the tube. A signal line (not shown) is further connected to the recording head 50.

The head drive circuit 55 is configured to drive the recording head 50 in accordance with a control signal from the print controller 30. The carriage transport mechanism 60 is configured to transmit power from the CR motor 71 to the carriage 61, thereby reciprocating the carriage 61 in the main scanning direction. The detailed configuration of the carriage transport mechanism 60 will be described later with reference to FIG. 2.

The CR motor 71 is composed of a DC motor. The motor drive circuit 73 is configured to supply drive power corresponding to the operation amount U input from the print controller 30 to the CR motor 71 to drive the CR motor 71.

According to one example, the motor drive circuit 73 can apply a drive voltage or drive current corresponding to the operation amount U to the CR motor 71 to drive the CR motor 71. According to one example, the motor drive circuit 73 can drive the CR motor 71 by PWM control.

The encoder 75 is a linear encoder that outputs an encoder signal corresponding to the displacement of the carriage 61 in the main scanning direction. The signal processing circuit 77 detects the position X and velocity V of the carriage 61 in the main scanning direction based on the encoder signal input from the encoder 75. The position X and velocity V of the carriage 61 detected by the signal processing circuit 77 are input to the print controller 30.

The print controller 30 determines the amount of operation for the CR motor 71 based on the position X and speed V of the carriage 61 input from the signal processing circuit 77, and controls the CR motor 71, so as to realize transport control of the carriage 61 according to commands from the main controller 10.

Specifically, the control of the CR motor 71 is realized by a motor controller 100 provided in the print controller 30. The detailed configuration of the motor controller 100 will be described later with reference to FIG. 3.

The print controller 30 further inputs a control signal to the head drive circuit 55 based on the position X of the carriage 61 input from the signal processing circuit 77 to realize ink ejection control according to commands from the main controller 10. As a result, ink is ejected from the recording head 50 onto the paper Q to form the image to be printed on the paper Q.

The transport controller 40 controls the PF motor 91 in accordance with instructions from the main controller 10, thereby controlling the transport of the paper Q. The image forming system 1 further includes a paper transport mechanism 80, a PF motor 91, a motor drive circuit 93, an encoder 95, and a signal processing circuit 97 as components related to the transport of the paper Q.

The paper transport mechanism 80 includes a transport roller 81. The paper transport mechanism 80 receives power from the PF motor 91 to rotate the transport roller 81, thereby transporting the paper Q in a sub-scanning direction perpendicular to the main scanning direction. As a result, the paper transport mechanism 80 sends out the paper Q in the sub-scanning direction in accordance with the operation of the recording head 50.

The PF motor 91 is composed of a DC motor. The motor drive circuit 93 applies a drive current to the PF motor 91 according to the operation amount input from the transport controller 40, and drives the PF motor 91. The encoder 95 is a rotary encoder that is disposed on the rotation axis of the PF motor 91 or the transport roller 81 and outputs an encoder signal according to the rotation of the PF motor 91 or the transport roller 81.

The signal processing circuit 97 detects the amount of rotation and the rotation speed of the transport roller 81 based on the encoder signal input from the encoder 95. The amount of rotation and the rotation speed of the transport roller 81 correspond to the amount of transport and the transport speed of the paper Q transported by the rotation of the transport roller 81.

The rotation amount and rotation speed detected by the signal processing circuit 97 are input to the transport controller 40. The transport controller 40 determines the operation amount for the PF motor 91 based on the rotation amount and rotation speed input from the signal processing circuit 97, and controls the PF motor 91. In this way, the transport controller 40 controls the transport of the paper Q by the transport roller 81.

As shown in FIG. 2, the carriage transport mechanism 60 includes a carriage 61, a belt mechanism 65, and guide rails 67 and 68. The belt mechanism 65 includes a drive pulley 651 and a driven pulley 653 arranged in the main scanning direction, and a belt 655 wound between the drive pulley 651 and the driven pulley 653.

The carriage 61 is fixed to the belt 655. In the belt mechanism 65, the drive pulley 651 rotates by receiving power from the CR motor 71, and the belt 655 and the driven pulley 653 rotate in accordance with the rotation of the drive pulley 651.

The guide rails 67 and 68 extend along the main scanning direction and are positioned at positions spaced apart from each other in the sub-scanning direction. The belt mechanism 65 is disposed on the guide rail 67. The guide rails 67 and 68 are formed with, for example, a convex wall (not shown) extending along the main scanning direction in order to regulate the movement direction of the carriage 61 in the main scanning direction.

The carriage 61, whose direction of movement is regulated by the guide rails 67, 68, moves and displaces along the main scanning direction on the guide rails 67, 68 in conjunction with the rotation of the belt 655. The recording head 50 moves in the main scanning direction in conjunction with the movement of the carriage 61.

The encoder 75 includes an encoder scale 75A and an optical sensor 75B. The encoder scale 75A is disposed on the guide rail 67 along the main scanning direction. The optical sensor 75B is mounted on the carriage 61. The encoder 75 inputs an encoder signal corresponding to a change in the relative position between the encoder scale 75A and the optical sensor 75B to the signal processing circuit 77.

The transport roller 81 is disposed parallel to the main scanning direction upstream of the recording head 50 in the sub-scanning direction. The transport roller 81 rotates by receiving power from the PF motor 91, and transports the paper Q transported from upstream downstream in the sub-scanning direction.

Next, the configuration of the motor controller 100 will be described. As shown in FIG. 3, the motor controller 100 includes a basic controller 110, a correction controller 120, and an adder 130.

The basic controller 110 is configured to calculate the operation amount Um for the CR motor 71 so as to realize the movement of the carriage 61 in accordance with the command from the main controller 10, without taking into account the load fluctuation taken into account by the correction controller 120. Hereinafter, this operation amount Um is also referred to as the basic operation amount Um.

The correction controller 120 is configured to output a correction amount Uc for correcting the basic operation amount Um in response to a load fluctuation acting on the carriage 61. The load can change, for example, when the ink supply tube or signal line connected to the carriage 61 bends as the carriage 61 moves.

In particular, when the tubes and signal lines are stiff, a large load is placed on the carriage 61 when they are bent. This load fluctuation depends on the position of the carriage 61. The correction controller 120 is provided to correct the amount of operation of the CR motor 71 in response to such position-dependent load fluctuation.

The adder 130 is configured to correct the basic operation amount Um from the basic controller 110 by adding the correction amount Uc from the correction controller 120, and input the corrected operation amount U = Um + Uc to the motor drive circuit 73. The motor drive circuit 73 drives the CR motor 71 so as to supply the CR motor 71 with drive power corresponding to the operation amount U input from the adder 130.

Specifically, the basic controller 110 calculates an operation amount Um corresponding to the deviation E = Vr(t) - V between the target speed Vr(t) at the corresponding time t and the detected speed V, so that the carriage 61 moves at the target speed Vr(t) specified by the main controller 10. The detected speed V here refers to the speed of the carriage 61 detected by the signal processing circuit 77.

According to one example, the basic controller 110 is configured to calculate a manipulated variable Um corresponding to the deviation E by PID control. When the derivative of the deviation E is expressed as D(E), the integral of the deviation E is expressed as I(E), the proportional gain is expressed as Kp, the derivative gain is expressed as Kd, and the integral gain is expressed as Ki, the manipulated variable Um is calculated according to the formula Um = Kp E + Kd D(E) + Ki I(E). One or both of the derivative gain Kd and the integral gain Ki may be zero.

The correction controller 120 is configured to input a constant non-zero value as the correction amount Uc to the adder 130 only when the carriage 61 is located in a predetermined correction section. The input correction amount Uc increases the drive power supplied to the CR motor 71, thereby functioning to increase the motor torque of the carriage 61 forward along its path. The increase in motor torque increases the propulsive force of the carriage 61 forward along its path.

As shown in FIG. 4, the correction section is a section upstream of the peak position, which is the point on the carriage transport path where the load acting on the carriage 61 reaches its peak, and is predetermined as a section where the load increases toward the peak position.

The top graph in Figure 4 shows the load fluctuations associated with the movement of the carriage 61 forward along its path, with the horizontal axis indicating position and the vertical axis indicating load. The graphs in the middle and bottom graphs in Figure 4 have a horizontal axis of the same scale as the top graph in Figure 4. The middle graph in Figure 4 is a graph showing the on/off state of the correction control. The bottom graph in Figure 4 is a graph showing the change in the correction amount Uc.

As can be seen from the bottom of FIG. 4, the correction amount Uc output by the correction controller 120 takes a constant non-zero value within the correction interval, and takes a value of zero outside the correction interval. The correction interval is determined, for example, by a load measurement experiment conducted before the shipment of the image forming system 1.

Because the carriage 61 reciprocates in the main scanning direction, the correction section can be determined for each of the forward and return journeys. The correction section for the forward journey can be determined as a section upstream of the forward journey peak position, based on the measurement data of the load when the carriage 61 moves forward on the forward journey, and using the forward journey peak position, which is the point where the load peaks on the forward journey, as a reference. The correction section for the return journey can be determined as a section upstream of the return journey peak position, based on the measurement data of the load when the carriage 61 moves forward on the return journey, and using the return journey peak position, which is the point where the load peaks on the return journey, as a reference.

In the correction section upstream of the peak position, the control of increasing the operation amount U by adding the correction amount Uc to the basic operation amount Um is performed for the purpose of giving momentum to the carriage 61 before the load acting on the carriage 61 reaches its peak. The movement of the carriage 61 realized by this control is conceptually similar to the movement of gaining momentum as it enters a steep slope and climbs to the top.

If the carriage 61 stops as the load increases, a motor torque that overcomes static friction is required to move the carriage 61 forward again, making it difficult to stably control the carriage 61's transport.

In this embodiment, by adding a correction amount Uc to the basic operation amount Um, the carriage 61 is given momentum in advance in the correction section upstream of the peak position, which makes it possible to prevent the carriage 61 from succumbing to the load and stopping or retreating before reaching the peak position.

Furthermore, by setting the end point of the correction section upstream of the peak position, the correction control can prevent the carriage 61 from passing through the peak position with excessive force.

Therefore, according to this embodiment, transport control can be performed appropriately even after the carriage 61 has passed the peak position. In other words, transport control of the carriage 61 can be performed appropriately not only before the carriage 61 has passed the peak position, but also after the carriage 61 has passed the peak position.

For proper transport control, the correction amount Uc can be determined by experimentation to be an appropriate value for the load. The correction amount Uc may be determined taking into account the maximum current that can be applied to the CR motor 71.

The basic controller 110, correction controller 120, and adder 130 described above may be provided in the motor controller 100 as dedicated circuits. Alternatively, the motor controller 100 may be equipped with a CPU and memory, and may function as the basic controller 110, correction controller 120, and adder 130 by executing processing according to a computer program.

According to one example, the motor controller 100 can realize the functions of the basic controller 110, the correction controller 120, and the adder 130 by repeatedly executing the control process shown in FIG. 5.

When the control process starts, the motor controller 100 calculates the basic operation amount Um (S110). Furthermore, based on the position X of the carriage 61 detected by the signal processing circuit 77, it is determined whether the carriage 61 is located in the correction zone (S120).

When it is determined that the carriage 61 is located in the correction section (Yes in S120), the motor controller 100 calculates the operation amount U = Um + Uc by adding a fixed correction amount Uc to the basic operation amount Um (S130), and inputs the operation amount U = Um + Uc to the motor drive circuit 73 (S140). This causes the motor drive circuit 73 to drive the CR motor 71 with the drive power corresponding to the operation amount U.

If it is determined that the carriage 61 is not located in the correction zone (No in S120), the motor controller 100 does not correct the basic operation amount Um, but inputs it to the motor drive circuit 73 as the operation amount U (S150).

By repeatedly executing the above-described control process, the motor controller 100 can update the operation amount U input to the motor drive circuit 73 for each control period. This allows the motor controller 100 to correct the operation amount U in response to the load increase at an appropriate time during the process in which the load acting on the carriage 61 increases toward the peak position, thereby increasing the motor torque and appropriately controlling the conveyance around the peak position of the carriage 61.

In the above example, whether the carriage 61 is located in the correction zone is determined based on the position X detected by the signal processing circuit 77, but it may be determined using another method. For example, the motor controller 100 may be configured to determine that the carriage 61 is located in the correction zone when the carriage 61 is in a time period in which it is estimated to be located in the correction zone based on the elapsed time from the start of control of the CR motor 71.

In other words, the correction control may be turned on and off based on the time elapsed since the start of the control. In this case, the time period during which the carriage 61 is estimated to be located in the correction zone when there is no control error may be preset as the correction period.

The technology of this embodiment described above is particularly useful in an environment where the tubes connected to the print head 50 are stiff and the load fluctuations on the carriage 61 are large. UV inkjet printers are known as inkjet printers with stiff tubes.

UV inkjet printers use ink that hardens when exposed to ultraviolet (UV) light, so tubes that have the ability to block UV light are used to supply the ink. Such tubes are hard. Therefore, the technology of this embodiment is particularly useful when applied to UV inkjet printers.

[Second embodiment]
Next, a description will be given of an image forming system 1 according to a second embodiment. In the image forming system 1 according to the second embodiment, the correction controller 120 is configured to output a correction amount Uc according to the speed V of the carriage 61 in the correction section.

The image forming system 1 of the second embodiment is configured similarly to the image forming system 1 of the first embodiment, except that the correction amount Uc is not a constant value. Therefore, in the following, we will omit a description of the same configuration as the image forming system 1 of the first embodiment, and will selectively describe the configuration of the image forming system 1 of the second embodiment that is different from the first embodiment.

The correction controller 120 of this embodiment outputs a correction amount Uc for the basic operation amount Um so that the speed V of the carriage 61 increases as the carriage 61 approaches the peak position when the carriage 61 passes through the correction section. The function of this correction controller 120 is realized by the motor controller 100 executing the control process shown in FIG. 6 instead of the control process shown in FIG. 5.

In the control process shown in FIG. 6, the motor controller 100 calculates the basic operation amount Um as in the first embodiment (S210). The motor controller 100 further determines whether the carriage 61 is located in the correction zone based on the position X of the carriage 61 detected by the signal processing circuit 77 (S220).

When it is determined that the carriage 61 is located in the correction zone (Yes in S220), the motor controller 100 determines whether it has just entered the correction zone (S230). When it is determined that it has just entered the correction zone (Yes in S230), the motor controller 100 sets a target speed profile in which the current detected speed V corresponding to the speed of the carriage 61 at the time of entering the correction zone is set to the initial value Vcr1 of the target speed Vcr (S240).

The target velocity profile indicates the target velocity Vcr(t) at each time point t when the carriage 61 passes through the correction section. The target velocity Vcr(t) is expressed by the following formula.
Vcr(t)=(Vcr2-Vcr1)/TL・(t-t1)+Vcr1

In the above formula, time t1 corresponds to the time when the carriage 61 passes the start point of the correction interval, and time (t-t1) corresponds to the elapsed time since the carriage 61 passed the start point of the correction interval. The speed Vcr2 corresponds to the target speed Vcr of the carriage 61 when it passes the end point of the correction interval. The target speed Vcr2 is set to, for example, a predetermined multiple of the initial value Vcr1. The predetermined multiple here is greater than 1.

The acceleration time TL is calculated according to the formula TL = |X2 - X1|/{(Vcr2 + Vcr1)/2}. X1 corresponds to the start position X1 of the correction section, and X2 corresponds to the end position of the correction section. In other words, the acceleration time TL corresponds to the passing time when the carriage 61, whose speed at the start point is Vcr1, passes through the correction section, whose distance from the start point to the end point is D = |X2 - X1|, while accelerating at a constant acceleration so that the carriage 61 reaches a speed of Vcr2 at the end point.

In other words, the target speed Vcr(t) is defined as the target speed for realizing constant acceleration motion in which the carriage 61 passes the start point of the correction interval at a speed Vcr1 and passes the end point of the correction interval at a speed Vcr2.

The lower part of Figure 7 shows the trajectory of this target speed Vcr(t) on a graph with the vertical axis representing speed. This target speed Vcr(t) is the target speed that is given to the correction controller 120 and used to calculate the correction amount Uc. Note that the target speed Vcr(t) is not the target speed that is given to the basic controller 110 and used to calculate the basic operating amount Um.

The upper and middle graphs in FIG. 7 are similar to the upper and middle graphs in FIG. 4. The process of S240 is executed only once, immediately after the carriage 61 enters the correction zone, while the carriage 61 is passing through the correction zone.

When the process in S240 is completed or a negative judgment is made in S230, the motor controller 100 calculates in S250 a correction amount Uc according to the deviation δ = Vcr(t) - V between the target speed Vcr(t) at the point in time t corresponding to the current time and the detected speed V of the carriage 61. Specifically, the motor controller 100 can calculate a correction amount Uc = K · δ that is proportional to the deviation δ. K is a proportional gain.

Then, the motor controller 100 calculates the corrected operation amount U = Um + Uc by adding the correction amount Uc calculated in S250 to the basic operation amount Um (S260), and inputs the corrected operation amount U = Um + Uc to the motor drive circuit 73 (S270). This causes the motor drive circuit 73 to drive the CR motor 71 with the drive power corresponding to the operation amount U.

On the other hand, if it is determined that the carriage 61 is not located in the correction zone (No in S220), the motor controller 100 inputs the basic operation amount Um to the motor drive circuit 73 as the operation amount U without correction (S290).

By repeatedly executing the above-described control process, the motor controller 100 can update the operation amount U input to the motor drive circuit 73 for each control period. This allows the motor controller 100 to appropriately correct the operation amount in response to an increase in load.

In particular, in this embodiment, the correction control is realized in the form of feedback control based on the detected speed V of the carriage 61. Therefore, the correction control that accelerates the carriage 61 toward the peak position can be appropriately executed based on the actual movement of the carriage 61. This is useful for appropriately controlling the transport of the carriage 61 around the peak position.

In the image forming system 1 of the second embodiment described above, as in the first embodiment, the correction control may be turned on/off based on the elapsed time from the start of control. In other words, whether the carriage 61 is located in the correction zone may be determined based on the elapsed time from the start of control.

In addition, the target speed Vcr(t) does not have to be a target speed that changes linearly. For example, the target speed Vcr(t) may be a constant value that corresponds to a predetermined multiple of the speed V of the carriage 61 when entering the correction section.

[Third embodiment]
Next, an image forming system 1 of a third embodiment will be described. The image forming system 1 of the third embodiment is configured similarly to the image forming system 1 of the first embodiment, except that the image forming system 1 of the third embodiment includes a motor controller 200 shown in Fig. 8 instead of the motor controller 100 shown in Fig. 3. Therefore, in the following, a description of the same configuration as the image forming system 1 of the first embodiment will be omitted, and configurations of the image forming system 1 of the third embodiment that are different from the first embodiment will be selectively described.

The motor controller 200 of this embodiment includes a basic controller 110, a correction controller 120, and an adder 130, which are configured in the same manner as in the first embodiment, as well as a range setter 210.

The section setter 210 is configured to acquire, as load data, time series data of a combination of the position X of the carriage 61 and the operation amount U observed during constant speed transport control of the carriage 61 by speed feedback control, and to set a correction section upstream of the peak position of the load on the path of the carriage 61 estimated from the load data. The correction controller 120 is configured to turn the correction control on and off based on the correction section set by the section setter 210.

The function of the section setter 210 can be realized by a dedicated circuit in the motor controller 200. Alternatively, the motor controller 200 can be equipped with a CPU and memory, and can function as the section setter 210 by executing processing according to a computer program.

Specifically, the motor controller 200 can function as the section setter 210 by executing the section setting process shown in FIG. 9. When the image forming system 1 is started up, the motor controller 200 can execute the section setting process in accordance with a command from the main controller 10.

When the section setting process starts, the motor controller 200 first acquires load data (S310). To acquire the load data, the motor controller 200 can execute constant speed transport control of the carriage 61.

Specifically, as constant speed transport control, the motor controller 200 calculates an operation amount U corresponding to the deviation E=Vr(t)-V between the target speed Vr(t) shown in the upper part of FIG. 10 and the detected speed V of the carriage 61, and inputs drive power corresponding to the operation amount U to the CR motor 71 via the motor drive circuit 73, thereby executing processing to control the CR motor 71. The constant speed transport control can be realized by PID control based on the deviation E, similar to the basic controller 110. The operation amount U in this case corresponds to the basic operation amount Um.

The target speed Vr(t) can be set to an optimal speed for searching for the load peak. The target speed Vr(t) includes an acceleration section, a constant speed section, and a deceleration section, and in the constant speed section, the target speed Vr(t) has a constant value Vc.

This constant speed transport control allows for time series data of combinations of the carriage 61 position X and the operation amount U in the acceleration section, constant speed section, and deceleration section to be obtained, as shown in the lower part of Figure 10. The lower part of Figure 10 shows the change in the operation amount U using a graph with the horizontal axis indicating the carriage 61 position X and the vertical axis indicating the operation amount U.

From this time series data, the motor controller 200 extracts the time series data of the constant speed section where speed control is performed based on a constant target speed Vr(t) = Vc as load data.

The motor controller 200 analyzes the load data acquired in this manner and detects the load peak in the constant speed section (S320). The operation amount U corresponds to the torque of the CR motor 71, and the torque corresponds to the load acting on the carriage 61. For this reason, in this embodiment, the change in the operation amount U in the constant speed section is regarded as a change in the load, and the peak of the operation amount U is detected as the load peak.

In this embodiment, peak detection is performed on the assumption that the load fluctuation is unimodal and that the peak of the operation amount U in the constant speed section exists at only one point. When detecting the peak, the motor controller 200 determines the peak position, which is the point where the load shows a peak, and the operation amount peak value U = Up, which is the operation amount at the peak position.

Furthermore, the motor controller 200 searches for the point where the operation amount U is the smallest in the constant speed section, and determines the reference position where the operation amount U is the smallest, and the operation amount reference value U = Uo, which is the operation amount at the reference position (S330). As another example, the motor controller 200 may determine the operation amount U at the start point of the constant speed section in the load data as the operation amount reference value U = Uo.

Then, based on the peak position, the operation volume peak value Up, and the operation volume reference value Uo, the motor controller 200 searches within the load data for a point upstream of the path of the carriage 61 from the peak position where the operation volume U represents a predetermined percentage A% of the operation volume peak value Up, and sets the corresponding point as the end point of the correction section (S340).

The ratio here corresponds to the ratio of the operation amount U to the operation amount peak value Up when the operation amount reference value Uo is set to 0% and the operation amount peak value Up is set to 100%. In other words, the end point of the correction section corresponds to a point on the course upstream of the peak position where the operation amount U in the load data indicates a value of {(Up-Uo) x (A/100) + Uo}.

The motor controller 200 can refer to the operation amount U of each position X in the load data from the peak position toward the upstream of the course, and set the point where the operation amount U indicates a percentage A% of the operation amount peak value Up as the end point of the correction section. The percentage A% is, for example, 80%.

Furthermore, the motor controller 200 searches for a point on the path of the carriage 61 upstream of the end point of the correction section where the operation amount U indicates a predetermined percentage B% of the operation amount peak value Up, and sets the corresponding point as the start point of the correction section (S350). The percentage B% is set to a value smaller than the percentage A% corresponding to the end point of the correction section. The percentage B% is, for example, 30%.

The motor controller 200 can sequentially refer to the operation amount U at each position X in the load data from the end point of the correction section toward the upstream of the course, and set the point where the operation amount U indicates a predetermined ratio B% of the operation amount peak value Up as the start point of the correction section. Hereinafter, this ratio is also referred to as the "load ratio."

In this way, the motor controller 200 sets the section with a load ratio of B% to A% as the correction section based on the load data, and ends the section setting process shown in Figure 9.

The top part of Figure 11 corresponds to a graph of the operation amount U, which shows an enlarged view of the constant speed section peak position in the graph in the bottom part of Figure 10. Here, the operation amount U is converted into a load ratio and shown on the vertical axis. The bottom part of Figure 11 is a graph showing, with a thick solid line, the on/off state of the correction control when a point with a load ratio of 30% is set as the start point of the correction section and a point with a load ratio of 80% is set as the end point of the correction section.

According to this embodiment, the correction section is updated each time the image forming system 1 is started by executing the section setting process (Figure 9). Therefore, even if the load changes over time, the operation amount can be appropriately corrected in response to an increase in load, and the influence of load fluctuations can be suppressed, and the transport control of the carriage 61 can be appropriately performed.

In addition, the above-mentioned section setting process can be executed for each traveling direction of the carriage 61. According to this example, it is possible to appropriately set and update the correction section for each traveling direction. The function as the section setter 210 of the third embodiment is not limited to the image forming system 1 of the first embodiment, and may be provided in the image forming system 1 of the second embodiment.

[Fourth embodiment]
Next, an image forming system 1 according to a fourth embodiment will be described. The fourth embodiment is an example in which the technical concept of the present disclosure is applied to minute transport control of the carriage 61 when the recording head 50 is capped.

The image forming system 1 of the fourth embodiment is basically configured in the same way as the image forming system 1 of the first embodiment, except for the configuration and processing related to the micro-transport control of the carriage 61. Therefore, in the following, the description of the same configuration as the image forming system 1 of the first embodiment will be omitted, and the configuration of the fourth embodiment that is different from the first embodiment will be selectively described.

As shown in FIG. 12A, the image forming system 1 of this embodiment includes a capping mechanism 69 at the end of the transport path of the carriage 61. The capping mechanism 69 is mechanically connected to a lever 69a that protrudes upward from a through hole 68a provided in the guide rail 68, and is configured to lift up a platform 692 equipped with a cap 691 in conjunction with the movement of the lever 69a.

When the carriage 61 moves through the terminal area of the transport path, the lever 69a comes into contact with the carriage 61, moves under the action of force from the carriage 61, and lifts the platform 692 upward. The carriage 61 is controlled by the print controller 30 to move to this terminal area when the print job is completed, whereby the recording head 50 is capped.

As shown in FIG. 12B, the platform 692 is supported by multiple (e.g., four) links 695 provided in the capping mechanism 69. The links 695 are rotatably connected to a portion of the image forming system 1 located below the platform 692, and lift the platform 692 up and down by rotating.

The capping mechanism 69 completes the attachment of the cap 691 to the recording head 50 when the carriage 61 is positioned at the end of the transport path. This covers the nozzle surface of the recording head 50. This end of the transport path corresponds to the home position of the carriage 61.

When the carriage 61 moves away from the lever 69a, in other words, from the home position toward the center of the transport path, the capping mechanism 69 is released from the force acting from the carriage 61 through the lever 69a, and uses gravity to lift down the platform 692.

In this way, the carriage 61 is subjected to a large load in the terminal area because it must move to the home position while in contact with the lever 69a connected to the capping mechanism 69. On the other hand, in the terminal area, it is necessary to prevent the nozzle surface from being damaged by the sliding of the cap 691 against the nozzle surface, so the carriage 61 must be moved to the home position at a low speed.

For this reason, the motor controller 100 is configured to execute the micro-transport control process shown in FIG. 13 in the terminal region. Micro-transport control is a control that gradually increases the operation amount U for the CR motor 71 from an initial value, and when the position X of the carriage 61 detected by the signal processing circuit 77 changes by a unit amount forward along the path, the operation amount U is lowered to the initial value, and the operation amount U is gradually increased again, thereby repeating this operation, thereby moving the carriage 61 by a small amount. The unit amount corresponds to the smallest unit of the position X of the carriage 61 that can be detected by the signal processing circuit 77.

The upper part of Figure 14 shows a graph with a horizontal axis indicating time and a vertical axis indicating the operation amount U, which shows how the operation amount U increases stepwise due to micro-conveyance control. The lower part of Figure 14 shows a graph with the same horizontal axis of time as the upper part of Figure 14 and a vertical axis indicating the position of the carriage 61, which shows the change in position of the carriage 61. As can be seen from the graph in the upper part of Figure 14, in the micro-conveyance control process, correction control is performed to increase the initial value of the operation amount U when the carriage 61 is located in the correction section.

When the micro-conveyance control process shown in FIG. 13 is started, the motor controller 100 sets the operation amount U for the CR motor 71 to a predetermined standard initial value Uk (S410). After that, the motor controller 100 executes an operation amount update process that increases the operation amount U by a predetermined amount from the current value (S420).

Next, the motor controller 100 determines whether the carriage 61 has moved forward due to an increase in the amount of operation U by determining whether the position X of the carriage 61 detected by the signal processing circuit 77 has changed forward in its path (S430).

If it is determined that the carriage 61 has not moved forward (No in S430), the motor controller 100 executes the operation amount update process (S420) to further increase the operation amount U from the current value by a predetermined amount. Then, it is determined whether the carriage 61 has moved forward (S430).

In this way, the motor controller 100 realizes the process of gradually increasing the operation amount U by a predetermined amount until the carriage 61 moves forward by repeatedly executing the operation amount update process.

When it is determined that the carriage 61 has moved forward (Yes in S430), the motor controller 100 determines whether the end condition of the micro-transport control process has been satisfied (S440). For example, the motor controller 100 can determine that the end condition has been satisfied when the carriage 61 has reached the home position, which is the end point of the transport path.

When the motor controller 100 determines that the termination condition is satisfied (Yes in S440), it terminates the micro-transport control process shown in FIG. 13. On the other hand, when it determines that the termination condition is not satisfied (No in S440), it determines whether the forward-moving carriage 61 is located in the correction zone (S450).

If it is determined that the carriage 61 is not located in the correction zone (No in S450), the motor controller 100 returns the operation amount U to the standard initial value Uk (S460), and executes a process of increasing the operation amount U by a predetermined amount from the initial value Uk until the carriage 61 moves forward (S420, S430).

On the other hand, if it is determined that the carriage 61 is located in the correction zone (Yes in S450), the motor controller 100 sets the operation amount U to a corrected initial value (Uk+Ukc) obtained by adding a certain correction amount Ukc to the standard initial value Uk, and executes a process of increasing the operation amount U by a predetermined amount from the corrected initial value (Uk+Ukc) until the carriage 61 moves forward (S420, S430).

By executing the micro-transport control process including these procedures, the motor controller 100 sets an initial value (Uk+Ukc) that is greater than the standard initial value Uk when the carriage 61 is located in a correction section upstream of the peak position. This provides momentum to the forward motion of the carriage 61 in the correction section.

Even when the operation amount U is returned to the initial value in the micro-transport control process, the carriage 61 basically continues to move forward due to inertia. Therefore, correcting the initial value to a larger value and shortening the time it takes for the carriage 61 to move forward a unit amount corresponds to increasing the speed of the carriage 61.

By giving the carriage 61 momentum in this way, as in the first and second embodiments, the carriage 61 can overcome the peak load and move appropriately to the end point of the transport path. Furthermore, it is possible to prevent the carriage 61 from moving to the end point of the transport path at an excessive speed, which would damage the recording head 50.

Although exemplary embodiments of the present disclosure have been described above, the present disclosure is not limited to the above embodiments and may take various forms. For example, the technology of the present disclosure may be applied to a control device that controls the displacement of a movable part in a mechanical structure that includes other movable parts, not just a carriage transport mechanism 60 that includes a carriage 61 as a movable part.

The correction section may be set or updated based on the abnormal stop position when an abnormal stop occurs in a moving part. For example, a control device to which the technology disclosed herein is applied may be configured to execute correction control by setting a predetermined section upstream of the abnormal stop position as the correction section when an abnormal stop occurs in a moving part, based on the abnormal stop position.

For example, as shown in FIG. 15, when the carriage 61 abnormally stops during transport control in the main scanning direction of the carriage 61 (Yes in S510), the motor controller 100 may be configured to execute a process of setting a correction section of a predetermined length upstream of the path at a predetermined distance from the abnormal stop position (S520).

When the carriage 61 passes through the correction section set in S520 in the direction of the abnormal stop position, the motor controller 100 may operate to input the operation amount U = Um + Uc, which is the basic operation amount Um plus the correction amount Uc, to the motor drive circuit 73.

In addition, the motor controller 100 may be configured to increase the correction amount Uc from the standard value when the carriage 61 stops even during correction control.

The functions of one component in the above embodiments may be distributed among multiple components. The functions of multiple components may be integrated into one component. Part of the configuration of the above embodiments may be omitted. At least part of the configuration of the above embodiments may be added to or substituted for the configuration of another of the above embodiments. All aspects included in the technical ideas identified from the wording of the claims are embodiments of the present disclosure.

1...image forming system, 10...main controller, 20...communication interface, 30...print controller, 40...transport controller, 50...recording head, 51...ink tank, 55...head drive circuit, 60...carriage transport mechanism, 61...carriage, 65...belt mechanism, 67...guide rail, 68...guide rail, 68a...through hole, 69...capping mechanism, 69a...lever, 71...CR motor, 73...motor drive circuit, 75...encoder, 77...signal processing circuit, 80...paper transport mechanism, 81...transport roller, 91...PF motor, 93...motor drive circuit, 95...encoder, 97...signal processing circuit, 100, 200...motor controller, 110...basic controller, 120...correction controller, 130...adder, 210...interval setter.

Claims (12)

A motor;
A movable part configured to be displaced by receiving power from the motor;
a controller configured to control the motor;
Equipped with
The controller:
a control process for controlling the motor by calculating an operation amount for the motor and inputting electric power corresponding to the operation amount to the motor;
A correction process for correcting the manipulated variable;
Run
In the control process, the manipulated variable is calculated so that each time the movable part is displaced a predetermined amount downstream in the displacement direction, the manipulated variable is lowered to an initial value and then gradually increased from the initial value, and when the manipulated variable is corrected by the correction process, the motor is controlled by inputting the power corresponding to the corrected manipulated variable to the motor;
In the correction process, when it is estimated that the movable part is displaced in the direction in which the load acting on the motor increases in a section in which the load is estimated to increase, the control device corrects the initial value to increase, thereby correcting the manipulated variable to increase. The control device according to claim 1 ,
The controller is a control device that corrects the manipulated variable by adding a predetermined correction amount to the manipulated variable in the correction process. The control device according to claim 1 ,
The controller is a control device that, in the correction process, corrects the manipulated variable by adding a correction amount corresponding to the deviation between a target speed and the speed of the movable part detected by a detector to the manipulated variable. A motor;
A movable part configured to be displaced by receiving power from the motor;
a controller configured to control the motor;
Equipped with
The controller:
a control process for controlling the motor by calculating an operation amount for the motor and inputting electric power corresponding to the operation amount to the motor;
A correction process for correcting the manipulated variable;
Run
In the control process, when the operation amount is corrected by the correction process, the electric power corresponding to the corrected operation amount is input to the motor to control the motor;
In the correction process, when it is estimated that the movable part is displaced in the direction in which the load acting on the motor increases in a section in which the load is estimated to increase , the control device corrects the operation amount by adding a correction amount corresponding to the deviation between a target speed and the speed of the movable part detected by a detector to the operation amount, thereby increasing the operation amount. The control device according to claim 3 or 4,
The controller is a control device that, in the correction process, sets the target speed based on the speed of the movable part when entering the section, which is detected by the detector. The control device according to any one of claims 3 to 5,
The controller is a control device that sets, as the target speed, a target speed that increases as the movable part is displaced in the section. A motor;
A movable part configured to be displaced by receiving power from the motor;
a controller configured to control the motor;
Equipped with
The controller:
a control process for controlling the motor by calculating an operation amount for the motor and inputting electric power corresponding to the operation amount to the motor;
A correction process for correcting the manipulated variable;
A section setting process;
Run
In the control process, when the operation amount is corrected by the correction process, the electric power corresponding to the corrected operation amount is input to the motor to control the motor;
the correction process performs correction so as to increase the operation amount when it is estimated that the movable part is displaced in a direction in which the load acting on the motor increases in a section in which the load is estimated to increase,
In the section setting process, the control device sets the section based on a change in load estimated from observation data of an operation amount for the motor obtained by feedback control of a displacement of the movable part. A motor;
A movable part configured to be displaced by receiving power from the motor;
a controller configured to control the motor;
Equipped with
The controller:
a control process for controlling the motor by calculating an operation amount for the motor and inputting electric power corresponding to the operation amount to the motor;
A correction process for correcting the manipulated variable;
A section setting process;
Run
In the control process, when the operation amount is corrected by the correction process, the electric power corresponding to the corrected operation amount is input to the motor to control the motor;
the correction process performs correction so as to increase the operation amount when it is estimated that the movable part is displaced in a direction in which the load acting on the motor increases in a section in which the load is estimated to increase,
In the section setting process ,
A control device that sets the section based on an abnormal stop position of the movable part when the movable part abnormally stops during a process of controlling the displacement of the movable part by the motor. A motor;
A movable part configured to be displaced by receiving power from the motor;
A method for controlling the motor in an apparatus comprising:
Calculating an operation amount for the motor;
Controlling the motor by inputting power corresponding to the operation amount to the motor;
correcting the manipulated variable; and
Including,
the controlling includes calculating the manipulated variable so that the manipulated variable is lowered to an initial value and then gradually increased from the initial value each time the movable part is displaced a predetermined amount downstream in the displacement direction, and when the manipulated variable is corrected, controlling the motor by inputting the power corresponding to the corrected manipulated variable to the motor;
The control method includes correcting the initial value to increase when it is estimated that the movable part is displaced in a direction in which the load acting on the motor increases in a section in which the load is estimated to increase , thereby correcting the manipulated variable to increase. A motor;
A movable part configured to be displaced by receiving power from the motor;
A method for controlling the motor in an apparatus comprising:
Calculating an operation amount for the motor;
Controlling the motor by inputting power corresponding to the operation amount to the motor;
correcting the manipulated variable; and
Including,
the controlling includes, when the operation amount is corrected, controlling the motor by inputting the electric power corresponding to the corrected operation amount to the motor;
The control method includes correcting the manipulated variable so as to increase it by adding a correction amount corresponding to a deviation between a target speed and a speed of the movable part detected by a detector to the manipulated variable when it is estimated that the movable part is displaced in a direction in which the load acting on the motor increases in a section in which the load is estimated to increase. A motor;
A movable part configured to be displaced by receiving power from the motor;
A method for controlling the motor in an apparatus comprising:
Calculating an operation amount for the motor;
Controlling the motor by inputting power corresponding to the operation amount to the motor;
correcting the manipulated variable; and
Including,
the controlling includes, when the operation amount is corrected, controlling the motor by inputting the electric power corresponding to the corrected operation amount to the motor;
the correcting step includes correcting the amount of operation so as to increase the amount of operation when it is estimated that the movable part is displaced in a direction in which the load acting on the motor increases in a section in which the load is estimated to increase ,
The control method includes:
Setting the section based on a change in load estimated from observed data of an operation amount for the motor obtained by feedback control of the displacement of the movable part.
The control method further comprises : A motor;
A movable part configured to be displaced by receiving power from the motor;
A method for controlling the motor in an apparatus comprising:
Calculating an operation amount for the motor;
Controlling the motor by inputting power corresponding to the operation amount to the motor;
correcting the manipulated variable; and
Including,
the controlling includes, when the operation amount is corrected, controlling the motor by inputting the electric power corresponding to the corrected operation amount to the motor;
the correcting step includes correcting the amount of operation so as to increase the amount of operation when it is estimated that the movable part is displaced in a direction in which the load acting on the motor increases in a section in which the load is estimated to increase ,
The control method includes:
The section is set based on an abnormal stop position of the movable part when the movable part abnormally stops during a process of controlling the displacement of the movable part by the motor.
The control method further comprises :

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