Control device, injection molding machine, and control method

Abstract

To provide a technology that easily suppresses an influence of disturbances applied to a controlled object.SOLUTION: A control device has a control part that creates a command value of a second physical quantity different from a first physical quantity according to a difference between the command value of the first physical quantity and an actual value, and controls a drive part of the controlled object according to the difference between the command value of the second physical quantity and the actual value. The control part has a disturbance correction part that estimates disturbance applied to the controlled object by using the actual value of the first physical quantity and the actual value or the command value of the second physical quantity, and corrects the command value of the second physical quantity to cancel the estimated disturbance.SELECTED DRAWING: Figure 5

Description

[Technical Field]

[0001] The present invention relates to a control device, an injection molding machine, and a control method. [Background Art]

[0002] The motor control device described in Patent Document 1 includes an auto-tuning unit that automatically adjusts control gains used by a position controller and a speed controller, using a motor torque value and a detected motor rotation speed value as input signals. The motor control device described in Patent Document 1 is used in industrial machinery (semiconductor manufacturing equipment, machine tools, injection molding machines), and is used to identify mechanical system parameters and improve control performance during online operation.

[0003] The condition monitoring device described in Patent Document 2 includes a state estimation model, and estimates the state of an equipment system that is difficult to model with a transfer function. Examples of the state of the equipment system include the quality of a product manufactured by an injection molding machine (e.g., the presence or absence of burrs) and the degree of deterioration of a mold. [Prior Art Documents] [Patent Documents]

[0004] [Patent Document 1] Japanese Patent No. 4340299 [Patent Document 2] International Publication No. WO 2018 / 220751 [Summary of the Invention] [Problem to be Solved by the Invention]

[0005] When suppressing the influence of disturbance, there are a large number of parameters for suppressing the influence of disturbance, resulting in complicated control calculations. In particular, in injection molding machines, since the characteristics of the molding material change over time, it has been difficult to suppress the variation in the characteristics of the molding material.

[0006] One aspect of the present invention provides a technique that easily suppresses the influence of disturbance applied to a control target. [Means for solving the problem]

[0007] A control device according to one aspect of the present invention includes a control unit that creates a command value for a second physical quantity different from the first physical quantity according to the difference between the command value and the actual value of the first physical quantity, and controls the drive unit of the controlled object according to the difference between the command value and the actual value of the second physical quantity. The control unit includes a disturbance correction unit that estimates disturbances acting on the controlled object using the actual value of the first physical quantity and the actual value or command value of the second physical quantity, and corrects the command value of the second physical quantity to cancel out the estimated disturbances. The disturbance correction unit has a model for estimating the current value used for outputting the controlled object from the current value input to the controlled object. The disturbance correction unit calculates a current disturbance value by comparing the current value estimated by the model with the current value input to the controlled object. [Effects of the Invention]

[0008] According to one aspect of the present invention, the effects of disturbances applied to the controlled object can be easily suppressed. [Brief explanation of the drawing]

[0009] [Figure 1] Figure 1 shows the state of an injection molding machine upon completion of mold opening according to one embodiment. [Figure 2] Figure 2 shows the state of an injection molding machine during mold clamping according to one embodiment. [Figure 3] Figure 3 is a diagram showing an example of the components of a control device in terms of functional blocks. [Figure 4] Figure 4 shows an example of the molding cycle process. [Figure 5] Figure 5 shows an injection control unit according to an embodiment. [Figure 6] Figure 6 shows an injection control unit according to a reference example. [Modes for carrying out the invention]

[0010] Embodiments of the present invention will be described below with reference to the drawings. In each drawing, the same or corresponding components are denoted by the same reference numerals, and their descriptions may be omitted.

[0011] (injection molding machine) Figure 1 shows the state of an injection molding machine when the mold opening is complete according to one embodiment. Figure 2 shows the state of the injection molding machine when the mold is clamped according to one embodiment. In this specification, the X-axis direction, Y-axis direction, and Z-axis direction are perpendicular to each other. The X-axis direction and Y-axis direction represent the horizontal direction, and the Z-axis direction represents the vertical direction. When the mold clamping device 100 is horizontal, the X-axis direction is the mold opening and closing direction, and the Y-axis direction is the width direction of the injection molding machine 10. The negative side in the Y-axis direction is called the operating side, and the positive side in the Y-axis direction is called the non-operating side.

[0012] As shown in Figures 1 and 2, the injection molding machine 10 includes a clamping device 100 for opening and closing the mold device 800, an ejector device 200 for ejecting the molded product formed in the mold device 800, an injection device 300 for injecting molding material into the mold device 800, a moving device 400 for moving the injection device 300 forward and backward relative to the mold device 800, a control device 700 for controlling each component of the injection molding machine 10, and a frame 900 for supporting each component of the injection molding machine 10. The frame 900 includes a clamping device frame 910 for supporting the clamping device 100 and an injection device frame 920 for supporting the injection device 300. The clamping device frame 910 and the injection device frame 920 are each installed on the floor 2 via leveling adjusters 930. The control device 700 is located in the internal space of the injection device frame 920. The components of the injection molding machine 10 will be described below.

[0013] (mold clamping device) In describing the mold clamping device 100, the direction of movement of the movable platen 120 when the mold is closed (for example, the positive X-axis direction) is described as forward, and the direction of movement of the movable platen 120 when the mold is open (for example, the negative X-axis direction) is described as backward.

[0014] The mold clamping device 100 performs mold closing, pressure increasing, mold clamping, pressure release, and mold opening of the mold apparatus 800. The mold apparatus 800 includes a fixed mold 810 and a movable mold 820.

[0015] The mold clamping device 100 is, for example, a horizontal type, and the mold opening / closing direction is a horizontal direction. The mold clamping device 100 includes: a fixed platen 110 to which a fixed mold 810 is attached; a movable platen 120 to which a movable mold 820 is attached; and a moving mechanism 102 that moves the movable platen 120 in the mold opening / closing direction relative to the fixed platen 110.

[0016] The fixed platen 110 is fixed to a mold clamping device frame 910. The fixed mold 810 is attached to a surface of the fixed platen 110 that faces the movable platen 120.

[0017] The movable platen 120 is disposed so as to be movable in the mold opening / closing direction relative to the mold clamping device frame 910. A guide 101 for guiding the movable platen 120 is laid on the mold clamping device frame 910. The movable mold 820 is attached to a surface of the movable platen 120 that faces the fixed platen 110.

[0018] The moving mechanism 102 performs mold closing, pressure boosting, mold clamping, pressure releasing, and mold opening of the mold device 800 by moving the movable platen 120 forward and backward relative to the fixed platen 110. The moving mechanism 102 includes: a toggle support 130 disposed at an interval from the fixed platen 110; a tie bar 140 that connects the fixed platen 110 and the toggle support 130; a toggle mechanism 150 that moves the movable platen 120 in the mold opening / closing direction relative to the toggle support 130; a mold clamping motor 160 that actuates the toggle mechanism 150; a motion conversion mechanism 170 that converts the rotational motion of the mold clamping motor 160 into linear motion; and a mold thickness adjusting mechanism 180 that adjusts the interval between the fixed platen 110 and the toggle support 130.

[0019] The toggle support 130 is disposed at an interval from the fixed platen 110, and is mounted on the mold clamping device frame 910 so as to be movable in the mold opening / closing direction. Note that the toggle support 130 may be disposed movably along a guide laid on the mold clamping device frame 910. The guide for the toggle support 130 may be the same guide 101 as that for the movable platen 120.

[0020] In this embodiment, the fixed platen 110 is fixed to the clamping device frame 910, and the toggle support 130 is arranged to be movable relative to the clamping device frame 910 in the mold opening and closing direction. However, the toggle support 130 may be fixed to the clamping device frame 910, and the fixed platen 110 may be arranged to be movable relative to the clamping device frame 910 in the mold opening and closing direction.

[0021] The tie bars 140 connect the fixed platen 110 and the toggle support 130 at a distance L in the mold opening and closing direction. Multiple tie bars 140 (for example, four) may be used. Multiple tie bars 140 are arranged parallel to the mold opening and closing direction and stretch in accordance with the clamping force. At least one tie bar 140 may be provided with a tie bar strain detector 141 that detects the strain of the tie bar 140. The tie bar strain detector 141 sends a signal indicating its detection result to the control device 700. The detection result of the tie bar strain detector 141 is used for detecting the clamping force, etc.

[0022] In this embodiment, a tie bar strain detector 141 is used as a clamping force detector to detect the clamping force, but the present invention is not limited to this. The clamping force detector is not limited to strain gauge type, but may be piezoelectric, capacitive, hydraulic, electromagnetic, etc., and its mounting position is not limited to the tie bar 140.

[0023] The toggle mechanism 150 is positioned between the movable platen 120 and the toggle support 130, and moves the movable platen 120 in the mold opening and closing direction relative to the toggle support 130. The toggle mechanism 150 has a crosshead 151 that moves in the mold opening and closing direction, and a pair of link groups that bend and extend as the crosshead 151 moves. Each of the link groups has a first link 152 and a second link 153 that are bendable and extendable connected by a pin or the like. The first link 152 is pivotably attached to the movable platen 120 by a pin or the like. The second link 153 is pivotably attached to the toggle support 130 by a pin or the like. The second link 153 is attached to the crosshead 151 via a third link 154. When the crosshead 151 moves forward and backward relative to the toggle support 130, the first link 152 and the second link 153 bend and extend, and the movable platen 120 moves forward and backward relative to the toggle support 130.

[0024] Furthermore, the configuration of the toggle mechanism 150 is not limited to the configuration shown in Figures 1 and 2. For example, in Figures 1 and 2, each link group has five nodes, but it may also have four, and one end of the third link 154 may be connected to the node between the first link 152 and the second link 153.

[0025] The clamping motor 160 is attached to the toggle support 130 and operates the toggle mechanism 150. The clamping motor 160 moves the crosshead 151 forward and backward relative to the toggle support 130, thereby bending and extending the first link 152 and the second link 153, and moving the movable platen 120 forward and backward relative to the toggle support 130. The clamping motor 160 is directly connected to the motion conversion mechanism 170, but it may also be connected to the motion conversion mechanism 170 via a belt, pulley, or the like.

[0026] The motion conversion mechanism 170 converts the rotational motion of the clamping motor 160 into the linear motion of the crosshead 151. The motion conversion mechanism 170 includes a screw shaft and a screw nut that screws onto the screw shaft. A ball or roller may be interposed between the screw shaft and the screw nut.

[0027] The mold clamping device 100 performs processes such as mold closing, pressure boosting, mold clamping, depressurization, and mold opening under the control of the control device 700.

[0028] In the mold closing process, the clamping motor 160 is driven to advance the crosshead 151 to the mold closing completion position at a set movement speed, thereby advancing the movable platen 120 and bringing the movable mold 820 into contact with the fixed mold 810. The position and movement speed of the crosshead 151 are detected using, for example, a clamping motor encoder 161. The clamping motor encoder 161 detects the rotation of the clamping motor 160 and sends a signal indicating the detection result to the control device 700.

[0029] Furthermore, the crosshead position detector for detecting the position of the crosshead 151 and the crosshead speed detector for detecting the movement speed of the crosshead 151 are not limited to the clamping motor encoder 161, and general-purpose devices can be used. Similarly, the movable platen position detector for detecting the position of the movable platen 120 and the movable platen speed detector for detecting the movement speed of the movable platen 120 are not limited to the clamping motor encoder 161, and general-purpose devices can be used.

[0030] In the boosting process, the clamping motor 160 is further driven to advance the crosshead 151 from the closed position to the clamping position, thereby generating clamping force.

[0031] In the clamping process, the clamping motor 160 is driven to maintain the position of the crosshead 151 in the clamping position. In the clamping process, the clamping force generated in the pressurization process is maintained. In the clamping process, a cavity space 801 (see Figure 2) is formed between the movable mold 820 and the fixed mold 810, and the injection unit 300 fills the cavity space 801 with liquid molding material. A molded product is obtained when the filled molding material solidifies.

[0032] The number of cavity spaces 801 may be one or more. In the latter case, multiple molded products can be obtained simultaneously. An insert material may be placed in part of the cavity space 801, and the molding material may be filled in the other part of the cavity space 801. A molded product in which the insert material and the molding material are integrated is obtained.

[0033] In the depressurization process, the clamping motor 160 is driven to retract the crosshead 151 from the clamping position to the mold opening start position, thereby retracting the movable platen 120 and reducing the clamping force. The mold opening start position and the mold closing completion position may be the same position.

[0034] In the mold opening process, the clamping motor 160 is driven to retract the crosshead 151 from the mold opening start position to the mold opening completion position at a set movement speed, thereby retracting the movable platen 120 and separating the movable mold 820 from the fixed mold 810. Subsequently, the ejector device 200 ejects the molded product from the movable mold 820.

[0035] The setting conditions for the mold closing process, the pressure boosting process, and the mold clamping process are set together as a series of setting conditions. For example, the movement speed and position of the crosshead 151 (including the mold closing start position, movement speed switching position, mold closing completion position, and mold clamping position), and the mold clamping force in the mold closing process and the pressure boosting process are set together as a series of setting conditions. The mold closing start position, movement speed switching position, mold closing completion position, and mold clamping position are arranged in this order from rear to front and represent the start and end points of the section in which the movement speed is set. The movement speed is set for each section. There may be one or more movement speed switching positions. There may be no movement speed switching positions. The mold clamping position and the mold clamping force may be set individually or individually.

[0036] The setting conditions for the depressurization process and the mold opening process are set similarly. For example, the movement speed and position of the crosshead 151 in the depressurization process and the mold opening process (mold opening start position, movement speed switching position, and mold opening completion position) are set together as a series of setting conditions. The mold opening start position, movement speed switching position, and mold opening completion position are arranged in this order from front to back and represent the start and end points of the sections in which the movement speed is set. The movement speed is set for each section. There may be one or more movement speed switching positions. There may be no movement speed switching positions. The mold opening start position and the mold closing completion position may be the same position. Also, the mold opening completion position and the mold closing start position may be the same position.

[0037] Furthermore, instead of the movement speed and position of the crosshead 151, the movement speed and position of the movable platen 120 may be set. Also, instead of the position of the crosshead (e.g., the clamping position) or the position of the movable platen, the clamping force may be set.

[0038] Incidentally, the toggle mechanism 150 amplifies the driving force of the clamping motor 160 and transmits it to the movable platen 120. This amplification ratio is also called the toggle ratio. The toggle ratio changes depending on the angle θ between the first link 152 and the second link 153 (hereinafter also referred to as the "link angle θ"). The link angle θ can be determined from the position of the crosshead 151. The toggle ratio is maximized when the link angle θ is 180°.

[0039] If the thickness of the mold device 800 changes due to replacement of the mold device 800 or a change in the temperature of the mold device 800, the mold thickness is adjusted so that a predetermined clamping force is obtained during mold clamping. In mold thickness adjustment, for example, the distance L between the fixed platen 110 and the toggle support 130 is adjusted so that the link angle θ of the toggle mechanism 150 becomes a predetermined angle at the time of mold touch when the movable mold 820 touches the fixed mold 810.

[0040] The mold clamping device 100 has a mold thickness adjustment mechanism 180. The mold thickness adjustment mechanism 180 adjusts the mold thickness by adjusting the distance L between the fixed platen 110 and the toggle support 130. The timing of the mold thickness adjustment is, for example, between the end of one molding cycle and the start of the next molding cycle. The mold thickness adjustment mechanism 180 includes, for example, a screw shaft 181 formed at the rear end of the tie bar 140, a screw nut 182 that is rotatably and immovably held by the toggle support 130, and a mold thickness adjustment motor 183 that rotates the screw nut 182 that is screwed onto the screw shaft 181.

[0041] A screw shaft 181 and screw nut 182 are provided for each tie bar 140. The rotational driving force of the mold thickness adjustment motor 183 may be transmitted to multiple screw nuts 182 via a rotational driving force transmission unit 185. Multiple screw nuts 182 can be rotated synchronously. It is also possible to rotate multiple screw nuts 182 individually by changing the transmission path of the rotational driving force transmission unit 185.

[0042] The rotational drive force transmission unit 185 is composed of, for example, gears. In this case, driven gears are formed on the outer circumference of each screw nut 182, a drive gear is attached to the output shaft of the mold thickness adjustment motor 183, and an intermediate gear that meshes with the multiple driven gears and the drive gear is rotatably held in the center of the toggle support 130. Note that the rotational drive force transmission unit 185 may be composed of a belt or pulley instead of gears.

[0043] The operation of the mold thickness adjustment mechanism 180 is controlled by the control device 700. The control device 700 drives the mold thickness adjustment motor 183 to rotate the screw nut 182. As a result, the position of the toggle support 130 relative to the tie bar 140 is adjusted, and the distance L between the fixed platen 110 and the toggle support 130 is adjusted. Multiple mold thickness adjustment mechanisms may be used in combination.

[0044] The interval L is detected using the mold thickness adjustment motor encoder 184. The mold thickness adjustment motor encoder 184 detects the amount and direction of rotation of the mold thickness adjustment motor 183 and sends a signal indicating the detection result to the control device 700. The detection result of the mold thickness adjustment motor encoder 184 is used to monitor and control the position and interval L of the toggle support 130. Note that the toggle support position detector for detecting the position of the toggle support 130 and the interval detector for detecting the interval L are not limited to the mold thickness adjustment motor encoder 184, but general-purpose devices can be used.

[0045] The clamping device 100 may have a mold temperature controller that adjusts the temperature of the mold device 800. The mold device 800 has a flow path for a temperature-controlled medium inside it. The mold temperature controller adjusts the temperature of the mold device 800 by adjusting the temperature of the temperature-controlled medium supplied to the flow path of the mold device 800.

[0046] In this embodiment, the mold clamping device 100 is a horizontal type in which the mold opening and closing direction is horizontal, but it may also be a vertical type in which the mold opening and closing direction is vertical.

[0047] In this embodiment, the clamping device 100 has a clamping motor 160 as a drive unit, but a hydraulic cylinder may be used instead of the clamping motor 160. Furthermore, the clamping device 100 may have a linear motor for opening and closing the mold, and an electromagnet for clamping the mold.

[0048] (Ejector device) In describing the ejector device 200, similar to the description of the clamping device 100, the direction of movement of the movable platen 120 when the mold is closed (for example, the positive X-axis direction) is described as forward, and the direction of movement of the movable platen 120 when the mold is open (for example, the negative X-axis direction) is described as backward.

[0049] The ejector device 200 is attached to the movable platen 120 and moves back and forth together with the movable platen 120. The ejector device 200 includes an ejector rod 210 that ejects the molded product from the mold device 800 and a drive mechanism 220 that moves the ejector rod 210 in the direction of movement of the movable platen 120 (in the X-axis direction).

[0050] The ejector rod 210 is positioned to move back and forth within a through-hole in the movable platen 120. The front end of the ejector rod 210 contacts the ejector plate 826 of the movable mold 820. The front end of the ejector rod 210 may or may not be connected to the ejector plate 826.

[0051] The drive mechanism 220 includes, for example, an ejector motor and a motion conversion mechanism that converts the rotational motion of the ejector motor into the linear motion of the ejector rod 210. The motion conversion mechanism includes a screw shaft and a screw nut that screws onto the screw shaft. A ball or roller may be interposed between the screw shaft and the screw nut.

[0052] The ejector device 200 performs the ejection process under the control of the control device 700. In the ejection process, the ejector rod 210 is advanced from the standby position to the ejection position at a set travel speed, thereby advancing the ejector plate 826 and ejecting the molded product. Subsequently, the ejector motor is driven to retract the ejector rod 210 at a set travel speed, retracting the ejector plate 826 back to its original standby position.

[0053] The position and speed of the ejector rod 210 are detected, for example, using an ejector motor encoder. The ejector motor encoder detects the rotation of the ejector motor and sends a signal indicating the detection result to the control device 700. Note that the ejector rod position detector, which detects the position of the ejector rod 210, and the ejector rod speed detector, which detects the speed of the ejector rod 210, are not limited to ejector motor encoders, but general-purpose devices can be used.

[0054] (injection device) In the description of the injection device 300, unlike the descriptions of the clamping device 100 and the ejector device 200, the direction of movement of the screw 330 during filling (for example, the negative X-axis direction) is described as forward, and the direction of movement of the screw 330 during metering (for example, the positive X-axis direction) is described as backward.

[0055] The injection device 300 is mounted on a slide base 301, which is positioned to move back and forth relative to the injection device frame 920. The injection device 300 is positioned to move back and forth relative to the mold device 800. The injection device 300 touches the mold device 800 and fills the cavity space 801 within the mold device 800 with molding material. The injection device 300 includes, for example, a cylinder 310 for heating the molding material, a nozzle 320 provided at the front end of the cylinder 310, a screw 330 positioned within the cylinder 310 to move back and forth and to rotate, a metering motor 340 for rotating the screw 330, an injection motor 350 for moving the screw 330 back and forth, and a load detector 360 for detecting the load transmitted between the injection motor 350 and the screw 330.

[0056] Cylinder 310 heats the molding material supplied to its interior from the supply port 311. The molding material includes, for example, resin. The molding material is formed, for example, into pellets and supplied to the supply port 311 in a solid state. The supply port 311 is formed at the rear of cylinder 310. A cooler 312, such as a water-cooled cylinder, is provided on the outer circumference of the rear of cylinder 310. In front of the cooler 312, a first heater 313, such as a band heater, and a first temperature detector 314 are provided on the outer circumference of cylinder 310.

[0057] The cylinder 310 is divided into multiple zones along its axial direction (for example, the X-axis direction). A first heater 313 and a first temperature detector 314 are provided in each of the multiple zones. A set temperature is set for each of the multiple zones, and the control device 700 controls the first heater 313 so that the temperature detected by the first temperature detector 314 becomes the set temperature.

[0058] The nozzle 320 is located at the front end of the cylinder 310 and is pressed against the mold device 800. A second heater 323 and a second temperature detector 324 are provided on the outer circumference of the nozzle 320. The control device 700 controls the second heater 323 so that the detected temperature of the nozzle 320 reaches a set temperature.

[0059] The screw 330 is rotatably and reciprocally positioned within the cylinder 310. When the screw 330 is rotated, the molding material is fed forward along the helical groove of the screw 330. As the molding material is fed forward, it is gradually melted by the heat from the cylinder 310. As the liquid molding material is fed forward to the screw 330 and accumulates at the front of the cylinder 310, the screw 330 is retracted. Then, when the screw 330 is advanced, the liquid molding material accumulated in front of the screw 330 is injected from the nozzle 320 and filled into the mold device 800.

[0060] A backflow prevention ring 331 is mounted on the front of the screw 330 so as to be able to move back and forth, acting as a backflow prevention valve to prevent backflow of the molding material from the front to the rear of the screw 330 when the screw 330 is pushed forward.

[0061] When the screw 330 is advanced, the backflow prevention ring 331 is pushed backward by the pressure of the molding material in front of the screw 330, and retracts relative to the screw 330 to a closed position (see Figure 2) that blocks the flow path of the molding material. This prevents the molding material accumulated in front of the screw 330 from flowing backward.

[0062] On the other hand, when the screw 330 is rotated, the backflow prevention ring 331 is pushed forward by the pressure of the molding material being sent forward along the helical groove of the screw 330, and moves relative to the screw 330 to an open position (see Figure 1) that opens the flow path of the molding material. As a result, the molding material is sent forward of the screw 330.

[0063] The backflow prevention ring 331 may be either a co-rotating type that rotates together with the screw 330, or a non-co-rotating type that does not rotate together with the screw 330.

[0064] Furthermore, the injection device 300 may have a drive source that moves the backflow prevention ring 331 back and forth between an open position and a closed position relative to the screw 330.

[0065] The metering motor 340 rotates the screw 330. The drive source for rotating the screw 330 is not limited to the metering motor 340; for example, a hydraulic pump or the like may also be used.

[0066] The injection motor 350 moves the screw 330 forward and backward. Between the injection motor 350 and the screw 330, there is a motion conversion mechanism that converts the rotational motion of the injection motor 350 into the linear motion of the screw 330. The motion conversion mechanism has, for example, a screw shaft and a screw nut that screws onto the screw shaft. Balls or rollers may be provided between the screw shaft and the screw nut. The drive source for moving the screw 330 forward and backward is not limited to the injection motor 350, but may also be, for example, a hydraulic cylinder.

[0067] The load detector 360 detects the load transmitted between the injection motor 350 and the screw 330. The detected load is converted into pressure by the control device 700. The load detector 360 is installed in the load transmission path between the injection motor 350 and the screw 330 and detects the load acting on the load detector 360.

[0068] The load detector 360 sends a signal of the detected load to the control device 700. The load detected by the load detector 360 is converted into pressure acting between the screw 330 and the molding material, and is used for controlling and monitoring the pressure the screw 330 receives from the molding material, the back pressure on the screw 330, and the pressure acting from the screw 330 on the molding material.

[0069] Furthermore, the pressure detector used to detect the pressure of the molding material is not limited to the load detector 360, but a general-purpose one can be used. For example, a nozzle pressure sensor or an in-mold pressure sensor may be used. The nozzle pressure sensor is installed in the nozzle 320. The in-mold pressure sensor is installed inside the mold device 800.

[0070] The injection device 300 performs processes such as metering, filling, and holding pressure under the control of the control device 700. The filling and holding pressure processes may be collectively referred to as the injection process.

[0071] In the metering process, the metering motor 340 is driven to rotate the screw 330 at a set rotational speed, and the molding material is fed forward along the helical groove of the screw 330. As this occurs, the molding material is gradually melted. As the liquid molding material is fed forward by the screw 330 and accumulates at the front of the cylinder 310, the screw 330 is retracted. The rotational speed of the screw 330 is detected, for example, using a metering motor encoder 341. The metering motor encoder 341 detects the rotation of the metering motor 340 and sends a signal indicating the detection result to the control device 700. Note that the screw rotational speed detector for detecting the rotational speed of the screw 330 is not limited to the metering motor encoder 341, and a general-purpose one can be used.

[0072] In the weighing process, the injection motor 350 may be driven to apply a set back pressure to the screw 330 in order to limit the rapid retraction of the screw 330. The back pressure on the screw 330 is detected, for example, using a load detector 360. The weighing process is completed when the screw 330 has retracted to the weighing completion position and a predetermined amount of molding material has accumulated in front of the screw 330.

[0073] The position and rotational speed of the screw 330 in the metering process are set together as a series of setting conditions. For example, the metering start position, rotational speed switching position, and metering completion position are set. These positions are arranged in this order from front to back and represent the start and end points of the sections in which the rotational speed is set. The rotational speed is set for each section. There may be one or more rotational speed switching positions. The rotational speed switching positions may not be set. In addition, back pressure is set for each section.

[0074] In the filling process, the injection motor 350 is driven to advance the screw 330 at a set speed, filling the cavity space 801 in the mold device 800 with the liquid molding material accumulated in front of the screw 330. The position and speed of the screw 330 are detected, for example, using an injection motor encoder 351. The injection motor encoder 351 detects the rotation of the injection motor 350 and sends a signal indicating the detection result to the control device 700. When the position of the screw 330 reaches the set position, a switchover from the filling process to the holding pressure process (so-called V / P switching) occurs. The position at which the V / P switching occurs is also called the V / P switching position. The set speed of the screw 330 may be changed depending on the position and time of the screw 330.

[0075] The position and movement speed of the screw 330 during the filling process are set together as a series of setting conditions. For example, the filling start position (also called the "injection start position"), the movement speed switching position, and the V / P switching position are set. These positions are arranged in this order from rear to front and represent the start and end points of the sections in which the movement speed is set. The movement speed is set for each section. There may be one or more movement speed switching positions. The movement speed switching positions may not be set at all.

[0076] For each section in which the movement speed of the screw 330 is set, an upper limit is set for the pressure of the screw 330. The pressure of the screw 330 is detected by the load sensor 360. If the pressure of the screw 330 is below the set pressure, the screw 330 moves forward at the set movement speed. On the other hand, if the pressure of the screw 330 exceeds the set pressure, for the purpose of protecting the mold, the screw 330 moves forward at a slower movement speed than the set movement speed so that the pressure of the screw 330 becomes below the set pressure.

[0077] Furthermore, during the filling process, after the screw 330 reaches the V / P switching position, the screw 330 may be temporarily stopped at the V / P switching position, and then the V / P switching may be performed. Immediately before the V / P switching, instead of stopping the screw 330, the screw 330 may be moved forward or backward at a slow speed. In addition, the screw position detector that detects the position of the screw 330 and the screw movement speed detector that detects the movement speed of the screw 330 are not limited to the injection motor encoder 351, but general-purpose ones can be used.

[0078] In the holding pressure process, the injection motor 350 is driven to push the screw 330 forward, maintaining the pressure of the molding material at the front end of the screw 330 (hereinafter also referred to as "holding pressure") at a set pressure, and pushing the molding material remaining in the cylinder 310 toward the mold device 800. This allows for the replenishment of molding material lost due to cooling shrinkage within the mold device 800. The holding pressure is detected, for example, using a load detector 360. The set value of the holding pressure may be changed according to the elapsed time from the start of the holding pressure process. Multiple holding pressures and holding times for maintaining the holding pressure in the holding pressure process may be set, and may be set together as a series of setting conditions.

[0079] During the holding pressure process, the molding material in the cavity space 801 within the mold device 800 is gradually cooled, and upon completion of the holding pressure process, the entrance to the cavity space 801 is sealed with solidified molding material. This state is called a gate seal, and prevents backflow of molding material from the cavity space 801. After the holding pressure process, the cooling process begins. During the cooling process, the molding material in the cavity space 801 is solidified. To shorten the molding cycle time, a metering process may be performed during the cooling process.

[0080] In this embodiment, the injection device 300 is an in-line screw type, but a pre-plasticization type or the like may also be used. In a pre-plasticization injection device, the molding material molten in a plasticizing cylinder is supplied to the injection cylinder, and the molding material is injected from the injection cylinder into the mold device. In the plasticizing cylinder, a screw is arranged to be rotatable but unable to move back and forth, or a screw is arranged to be rotatable and able to move back and forth. On the other hand, a plunger is arranged to be able to move back and forth in the injection cylinder.

[0081] Furthermore, although the injection device 300 in this embodiment is a horizontal type with the axial direction of the cylinder 310 being horizontal, it may also be a vertical type with the axial direction of the cylinder 310 being vertical. The clamping device combined with the vertical injection device 300 may be vertical or horizontal. Similarly, the clamping device combined with the horizontal injection device 300 may be horizontal or vertical.

[0082] (Mobile device) In describing the moving device 400, similar to the description of the injection device 300, the direction of movement of the screw 330 during filling (for example, the negative X-axis direction) is described as forward, and the direction of movement of the screw 330 during metering (for example, the positive X-axis direction) is described as backward.

[0083] The moving device 400 moves the injection device 300 forward and backward relative to the mold device 800. The moving device 400 also presses the nozzle 320 against the mold device 800, generating nozzle touch pressure. The moving device 400 includes a hydraulic pump 410, a motor 420 as a drive source, a hydraulic cylinder 430 as a hydraulic actuator, and the like.

[0084] The hydraulic pump 410 has a first port 411 and a second port 412. The hydraulic pump 410 is a bidirectional pump, and by switching the rotation direction of the motor 420, it can draw in working fluid (e.g., oil) from either the first port 411 or the second port 412 and discharge it from the other to generate hydraulic pressure. The hydraulic pump 410 can also draw working fluid from a tank and discharge it from either the first port 411 or the second port 412.

[0085] Motor 420 operates the hydraulic pump 410. Motor 420 drives the hydraulic pump 410 with a rotational direction and rotational torque corresponding to the control signal from the control device 700. Motor 420 may be an electric motor or an electric servo motor.

[0086] The hydraulic cylinder 430 comprises a cylinder body 431, a piston 432, and a piston rod 433. The cylinder body 431 is fixed to the injection device 300. The piston 432 divides the inside of the cylinder body 431 into a front chamber 435 as a first chamber and a rear chamber 436 as a second chamber. The piston rod 433 is fixed to the fixed platen 110.

[0087] The front chamber 435 of the hydraulic cylinder 430 is connected to the first port 411 of the hydraulic pump 410 via a first passage 401. The hydraulic fluid discharged from the first port 411 is supplied to the front chamber 435 via the first passage 401, pushing the injection device 300 forward. As the injection device 300 moves forward, the nozzle 320 is pressed against the fixed mold 810. The front chamber 435 functions as a pressure chamber that generates nozzle touch pressure on the nozzle 320 by the pressure of the hydraulic fluid supplied from the hydraulic pump 410.

[0088] Meanwhile, the rear chamber 436 of the hydraulic cylinder 430 is connected to the second port 412 of the hydraulic pump 410 via the second passage 402. The working fluid discharged from the second port 412 is supplied to the rear chamber 436 of the hydraulic cylinder 430 via the second passage 402, pushing the injection device 300 backward. As the injection device 300 is retracted, the nozzle 320 is separated from the fixed mold 810.

[0089] In this embodiment, the moving device 400 includes a hydraulic cylinder 430, but the present invention is not limited thereto. For example, instead of the hydraulic cylinder 430, an electric motor and a motion conversion mechanism that converts the rotational motion of the electric motor into the linear motion of the injection device 300 may be used.

[0090] (Control device) The control device 700 is, for example, a computer and, as shown in Figures 1 and 2, has a CPU (Central Processing Unit) 701, a storage medium 702 such as memory, an input interface 703, and an output interface 704. The control device 700 performs various controls by having the CPU 701 execute a program stored in the storage medium 702. The control device 700 also receives signals from the outside through the input interface 703 and transmits signals to the outside through the output interface 704.

[0091] The control device 700 repeatedly manufactures molded products by repeatedly performing processes such as metering, mold closing, pressure increasing, mold clamping, filling, holding pressure, cooling, depressurization, mold opening, and ejection. A series of operations to obtain a molded product, such as the operations from the start of one metering process to the start of the next metering process, is also called a "shot" or "molding cycle." The time required for one shot is also called the "molding cycle time" or "cycle time."

[0092] A single molding cycle includes, for example, a weighing process, a mold closing process, a pressurizing process, a clamping process, a filling process, a holding pressure process, a cooling process, a depressurizing process, a mold opening process, and an ejection process, in this order. The order here refers to the order in which each process begins. The filling, holding pressure, and cooling processes take place during the clamping process. The start of the clamping process may coincide with the start of the filling process. The completion of the depressurizing process coincides with the start of the mold opening process.

[0093] Furthermore, multiple processes may be performed simultaneously in order to shorten the molding cycle time. For example, the metering process may be performed during the cooling process of the previous molding cycle, or during the mold clamping process. In this case, the mold closing process may be performed at the beginning of the molding cycle. The filling process may also be started during the mold closing process. The ejection process may also be started during the mold opening process. If an on-off valve is provided to open and close the flow path of the nozzle 320, the mold opening process may be started during the metering process. This is because even if the mold opening process is started during the metering process, if the on-off valve closes the flow path of the nozzle 320, the molding material will not leak from the nozzle 320.

[0094] Furthermore, a single molding cycle may include steps other than the weighing step, mold closing step, pressurization step, mold clamping step, filling step, holding pressure step, cooling step, depressurization step, mold opening step, and ejection step.

[0095] For example, after the holding pressure process is completed and before the metering process begins, a pre-metering suck-back process may be performed in which the screw 330 is retracted to a preset metering start position. This reduces the pressure of the molding material accumulated in front of the screw 330 before the metering process begins and prevents the screw 330 from retracting too quickly at the start of the metering process.

[0096] Furthermore, after the metering process is completed and before the filling process begins, a post-metering suck-back process may be performed in which the screw 330 is retracted to a preset filling start position (also called the "injection start position"). This reduces the pressure of the molding material accumulated in front of the screw 330 before the filling process begins and prevents leakage of the molding material from the nozzle 320 before the filling process begins.

[0097] The control device 700 is connected to an operating device 750 that accepts user input operations and a display device 760 that displays a screen. The operating device 750 and the display device 760 may be integrated, for example, by a touch panel 770. The touch panel 770, as the display device 760, displays a screen under the control of the control device 700. The screen of the touch panel 770 may display information such as the settings of the injection molding machine 10 and the current status of the injection molding machine 10. The screen of the touch panel 770 may also display operation parts such as buttons and input fields that accept user input operations. The touch panel 770, as the operating device 750, detects user input operations on the screen and outputs a signal corresponding to the input operation to the control device 700. This allows, for example, the user to operate the operation parts provided on the screen while confirming the information displayed on the screen to set the injection molding machine 10 (including inputting setting values). Furthermore, by operating the operation parts provided on the screen, the user can make the injection molding machine 10 operate in accordance with the operation part. The operation of the injection molding machine 10 may also include the operation (including stopping) of, for example, the clamping device 100, the ejector device 200, the injection device 300, the moving device 400, etc. Furthermore, the operation of the injection molding machine 10 may also include switching the screens displayed on the touch panel 770, which serves as the display device 760.

[0098] Although the operating device 750 and display device 760 of this embodiment have been described as being integrated as a touch panel 770, they may be provided independently. Furthermore, multiple operating devices 750 may be provided. The operating device 750 and display device 760 are positioned on the operating side (negative Y-axis direction) of the clamping device 100 (more specifically, the fixed platen 110).

[0099] (Details of the control device) Next, an example of the components of the control device 700 will be described with reference to Figure 3. Note that the functional blocks shown in Figure 3 are conceptual and do not necessarily have to be physically configured as shown. All or part of each functional block can be functionally or physically distributed and integrated in any unit. Each processing function performed by each functional block can be implemented, in whole or in part, by a program executed on the CPU, or by hardware using wired logic.

[0100] As shown in Figure 3, the control device 700 includes, for example, a mold clamping control unit 711, an ejector control unit 712, an injection control unit 713, and a metering control unit 714. The mold clamping control unit 711 controls the mold clamping device 100 and performs the mold closing process, pressure boosting process, mold clamping process, depressurization process, and mold opening process shown in Figure 4. The ejector control unit 712 controls the ejector device 200 and performs the ejection process. The injection control unit 713 controls the injection drive source of the injection device 300 and performs the injection process. The injection drive source is, for example, an injection motor 350, but may also be a hydraulic cylinder or the like. The injection process includes a filling process and a holding pressure process. The injection process is performed during the mold clamping process. The metering control unit 714 controls the metering drive source of the injection device 300 and performs the metering process. The metering drive source is, for example, a metering motor 340, but may also be a hydraulic pump or the like.

[0101] The filling process involves controlling the injection drive source so that the actual value of the movement speed of the injection member located inside the cylinder 310 reaches a set value. The filling process involves moving the injection member forward to fill the inside of the mold device 800 with liquid molding material (e.g., resin) accumulated in front of the injection member. The injection member is, for example, a screw 330, but it may also be a plunger.

[0102] The movement speed of the injection member is detected using a speed detector. The speed detector is, for example, an injection motor encoder 351. In the filling process, as the injection member moves forward, the pressure acting on the molding material from the injection member increases. The filling process may include a step of temporarily stopping the injection member or a step of retracting the injection member immediately before the holding pressure process.

[0103] The holding pressure process is a process of controlling the injection drive source so that the actual pressure acting on the molding material from the injection member reaches a set value. The holding pressure process is a process of replenishing the molding material that has been lost due to cooling shrinkage within the mold device 800 by pushing the injection member forward. The pressure is detected using a pressure detector such as a load detector 360. A nozzle pressure sensor or an in-mold pressure sensor may be used as the pressure detector.

[0104] Next, before describing the injection control unit 713A according to an embodiment with reference to Figure 5, we will describe the injection control unit 713B according to a reference example with reference to Figure 6. In the following description, the set value may be referred to as the command value.

[0105] The injection control unit 713B controls the injection device 300 shown in Figures 1 and 2, and an inverter (not shown) that supplies alternating current to the injection device 300. The injection device 300, as the control unit 713, includes an injection motor 350 and a transmission mechanism that transmits the driving force of the injection motor 350 to the molding material. The transmission mechanism includes a motion conversion mechanism such as a ball screw that converts the rotational motion of the injection motor 350 into the linear motion of the screw 330, and the screw 330.

[0106] As will be explained in more detail later, the injection control unit 713B creates a current command value Iref for the injection motor 350 according to the difference Vdev (Vdev = Vref - Vdet) between the rotational speed command value Vref and the actual rotational speed value Vdet of the injection motor 350. The injection control unit 713B also controls the controlled object according to the difference Idev (Idev = Iref - Idet) between the current command value Iref and the actual current value Idet of the injection motor 350.

[0107] The rotational speed of the injection motor 350 is an example of the first physical quantity, and the current of the injection motor 350 is an example of the second physical quantity. Alternatively, the moving speed of the screw 330 may be used as the first physical quantity. The moving speed of the screw 330 is proportional to the rotational speed of the injection motor 350. The greater the rotational speed of the injection motor 350, the greater the moving speed of the screw 330.

[0108] As shown in Figure 6, the injection control unit 713B includes, for example, a first subtraction unit 781, a current command creation unit 782, a second subtraction unit 783, and a voltage command creation unit 784. The first subtraction unit 781 calculates the difference Vdev (Vdev = Vref - Vdet) between the rotational speed command value Vref and the actual rotational speed value Vdet of the injection motor 350. The actual rotational speed value Vdet is obtained by the speed detector 785. As described above, for example, the injection motor encoder 351 is used as the speed detector 785.

[0109] The current command generation unit 782 generates a current command value Iref for the injection motor 350 such that the magnitude of the difference Vdev calculated by the first subtraction unit 781 becomes small (preferably zero). For example, PI calculation or PID calculation is used to generate the current command value Iref. The second subtraction unit 783 calculates the difference Idev (Idev = Iref - Idet) between the current command value Iref and the actual current value Idet. The actual current value Idet is obtained by the current detector 786. The current detector is attached to the inverter or the injection motor 350, for example.

[0110] The voltage command generation unit 784 generates a voltage command value such that the magnitude of the difference Idev calculated by the second subtraction unit 783 becomes small (preferably zero). The inverter supplies alternating current to the injection motor 350 according to the voltage command value generated by the voltage command generation unit 784.

[0111] Note that the injection control unit 713B may not have some of the components shown in Figure 6. Also, the injection control unit 713B may have components not shown in Figure 6. For example, the injection control unit 713B may have a torque command generation unit (not shown) instead of the current command generation unit 782. This is because the torque of the injection motor 350 is approximately proportional to the current of the injection motor 350.

[0112] The torque command generation unit generates the torque command value Tref for the injection motor 350 so that the magnitude of the difference Vdev calculated by the first subtraction unit 781 becomes small (preferably zero). The second subtraction unit 783 calculates the difference Tdev (Tdev = Tref - Tdet) between the torque command value Tref and the actual torque value Tdet. The voltage command generation unit 784 generates the voltage command value so that the magnitude of the difference Tdev calculated by the second subtraction unit 783 becomes small (preferably zero).

[0113] The injection molding machine 10 heats and melts the molding material (for example, resin) inside the cylinder 310. A screw 330 is provided inside the cylinder 310 so as to be able to move back and forth, and the molten molding material accumulates in front of the screw 330. The injection molding machine 10 moves the screw 330 forward, filling the cavity space 801 inside the mold device 800 with the molten molding material and solidifying it. This produces a molded product.

[0114] Conventionally, the properties of the molding material change over time, which in turn causes the magnitude of disturbances acting on the controlled object to change over time, making it difficult to suppress the effects of these disturbances. For example, in the filling process, as the filling of the molding material progresses, the reaction force acting from the molding material on the screw 330 increases, sometimes causing the forward speed of the screw 330 to drop below the set value. As a result, the molding material may solidify before it completely fills the cavity space 801, leading to a molding defect called a short.

[0115] If the speed control gain is increased to suppress the decrease in the forward speed of the screw 330, oscillation occurs in the injection motor 350 that moves the screw 330 forward, resulting in molding defects. Also, while it is conceivable to set the temperature of the cylinder 310 higher to improve the fluidity of the molding material, if the temperature of the molding material is too high, molding defects called burning will occur.

[0116] Next, the injection control unit 713A according to the embodiment will be described with reference to Figure 5. Below, the differences from the injection control unit 713B according to the reference example will be mainly described. The injection control unit 713A has a disturbance correction unit 790. The disturbance correction unit 790 is a disturbance observer that estimates disturbances applied to the controlled object using the actual rotational speed value Vdet and the actual current value Idet, and corrects the current command value Iref to cancel out the estimated disturbance. By estimating disturbances applied to the controlled object with the disturbance observer and feeding them back to the input to the controlled object, the effects of disturbances can be easily and quickly removed when disturbances occur.

[0117] The disturbance correction unit 790 may estimate the disturbance applied to the controlled object using current command values ​​Iref and Irefa instead of the actual current value Idet. The disturbance correction unit 790 estimates the current value Ir input to the injection motor 350 using the actual current value Idet, but it is also possible to estimate the current value Ir using current command values ​​Iref and Irefa instead of the actual current value Idet.

[0118] The disturbance correction unit 790 has an inverse model 791 that estimates the current value Im used for the rotation of the injection motor 350 from the current value Ir input to the injection motor 350, for example, from the actual rotational speed value Vdet of the injection motor 350. The disturbance correction unit 790 also has a subtraction unit 792 that compares the current value Im estimated by the inverse model 791 with the current value Ir input to the injection motor 350. The subtraction unit 792 calculates the current disturbance value Id (Id = Ir - Im) caused by the disturbance applied to the controlled object by subtracting Im from Ir.

[0119] The disturbance correction unit 790 has an adder 793 that adds the current command value Iref created by the current command creation unit 782 and the current disturbance value Id. The adder 793 inputs the added value (Iref + Id) as the corrected current command value Irefa to the second subtraction unit 783. Here, if the current disturbance value Id is zero, the corrected current command value Irefa is equal to the current command value Iref before correction. The second subtraction unit 783 calculates the difference Ideva (Ideva = Irefa - Idet) between the corrected current command value Irefa and the actual current value Idet.

[0120] The voltage command generation unit 784 generates a voltage command value such that the magnitude of the difference Ideva calculated by the second subtraction unit 783 becomes small (preferably zero). The inverter supplies AC current to the injection motor 350 according to the voltage command value generated by the voltage command generation unit 784. By estimating the current disturbance value Id in this way and feeding it back to the input to the controlled object, the effects of disturbances can be easily and quickly removed when disturbances occur.

[0121] The inverse model 791 estimates the current value Im based on the mechanical properties of the controlled object, without considering the properties of the molding material. The mechanical properties of the controlled object include, for example, the moment of inertia of the controlled object and the viscous friction coefficient of the controlled object. In this embodiment, in order to simplify the model, the properties of the mechanical parts on the injection motor 350 side of the screw 330 coupling, particularly the ball screw, bearings, and injection motor 350, are considered, while the influence of the properties of the molding material is not considered. The properties of the mechanical parts on the cylinder 310 side of the screw 330 coupling are not considered, but may be considered. The inverse model 791 is created from the equation of motion of the controlled object. The properties of the molding material (e.g., viscosity) change over time and are therefore difficult to model. By not considering the properties of the molding material, the control calculation can be simplified.

[0122] The disturbance correction unit 790 uses the value obtained by processing the actual current value Idet with a first-order low-pass filter 794 as the current value Ir, which is compared with the current value Im estimated by the inverse model 791. By representing the model of the electrical characteristics of the controlled object (e.g., current loss due to electrical resistance) with a first-order low-pass filter 794, the control calculation can be simplified. Note that the actual current value Idet is the actual current value after converting three-phase AC to two-phase AC.

[0123] For example, the disturbance correction unit 790 includes a multiplication unit 795 that multiplies the actual current value Idet detected by the current detector 786 by a torque multiplier Kt to output an actual torque value Tdet (Tdet = Idet × Kt), and a first-order low-pass filter 794 that outputs a current value Ir by taking the output of the multiplication unit 795 (actual torque value Tdet) as input. The first-order low-pass filter 794 is a first-order lag filter.

[0124] Note that the configuration of the injection control unit 713A is not limited to the configuration shown in the block diagram of Figure 5. For example, the position of the primary low-pass filter 794 can be changed, and the configuration of the injection control unit 713A may be an equivalent transformation of the block diagram of Figure 5.

[0125] The above describes an example of applying the present invention to the injection control unit 713, but the present invention can also be applied to the mold clamping control unit 711, the ejector control unit 712, and the metering control unit 714.

[0126] The clamping control unit 711 controls a clamping device 100 shown in Figures 1 and 2, and an inverter (not shown) that supplies alternating current to the clamping device 100. The clamping device 100, as the object of control of the clamping control unit 711, includes a clamping motor 160 and a transmission mechanism that transmits the driving force of the clamping motor 160 to the molding material. The transmission mechanism includes a motion conversion mechanism 170 such as a ball screw that converts the rotational motion of the clamping motor 160 into the linear motion of the crosshead 151, a toggle mechanism 150 including the crosshead 151, a movable platen 120 that moves forward and backward by the toggle mechanism 150, and a movable mold 820 that moves forward and backward together with the movable platen 120. During clamping, a cavity space 801 is formed between the movable mold 820 and the fixed mold 810, and the molding material is filled into the cavity space 801. The movable mold 820 is pushed back by the pressure of the molding material. Therefore, as the properties of the molding material change over time during the injection process, the disturbances applied to the object controlled by the clamping control unit 711 may also change over time. By applying the present invention to the clamping control unit 711, the disturbances applied to the object can be estimated and fed back into the input to the object, making it possible to easily and quickly eliminate the effects of disturbances when they occur.

[0127] The ejector control unit 712 controls the ejector device 200 shown in Figures 1 and 2, and an inverter (not shown) that supplies alternating current to the ejector device 200. The ejector device 200, as the object of control of the ejector control unit 712, includes an ejector motor and a transmission mechanism that transmits the driving force of the ejector motor to the molding material. The transmission mechanism includes a motion conversion mechanism such as a ball screw that converts the rotational motion of the ejector motor into the linear motion of the ejector rod 210, the ejector rod 210, and an ejector plate 826 that moves back and forth together with the ejector rod 210. The ejector device 200 is capable of compressing the molding material filled in the cavity space 801 during mold clamping. The compression of the molding material is performed before the molding material has completely solidified and during the injection process. At this time, the ejector plate 826 is pushed back by the pressure of the molding material. Therefore, as the properties of the molding material change over time during the injection process, the disturbances applied to the object controlled by the ejector control unit 712 may also change over time. By applying the present invention to the ejector control unit 712, the disturbances applied to the object can be estimated and fed back into the input to the object, making it possible to easily and quickly eliminate the effects of disturbances when they occur.

[0128] The metering control unit 714 controls the injection device 300 shown in Figures 1 and 2, and an inverter (not shown) that supplies alternating current to the injection device 300. The injection device 300, as a control of the metering control unit 714, includes a metering motor 340 and a transmission mechanism that transmits the driving force of the metering motor 340 to the molding material. The transmission mechanism includes a coupling that transmits the rotational motion of the metering motor 340 to the screw 330, and the screw 330. The screw 330 is rotatably and reciprocally mounted inside the cylinder 310. In the metering process, the resin pellet is fed forward along the helical groove of the screw 330 by rotating the screw 330. As the resin pellet is fed forward, it gradually melts due to the heat from the cylinder 310. In the metering process, new resin pellets are supplied into the cylinder 310, and the temperature distribution of the resin inside the cylinder 310 changes over time. Therefore, the properties of the molding material change over time during the weighing process, and the disturbances applied to the controlled object of the weighing control unit 714 may also change over time. By applying the present invention to the weighing control unit 714, the disturbances applied to the controlled object can be estimated and fed back into the input to the controlled object, thereby easily and quickly eliminating the effects of disturbances when they occur.

[0129] The present invention may be applied to machines other than injection molding machines, or to control devices for machines other than injection molding machines.

[0130] While embodiments of the control device, injection molding machine, and control method according to the present invention have been described above, the present invention is not limited to the above embodiments. Various changes, modifications, substitutions, additions, deletions, and combinations are possible within the scope described in the claims. These also naturally fall within the technical scope of the present invention. [Explanation of Symbols]

[0131] 10 injection molding machine 700 Control Unit 713 Injection Control Unit (Control Unit) 790 Disturbance Correction Unit

Claims

1. A control device having a control unit that creates a command value for a second physical quantity different from the first physical quantity according to the difference between the command value and the actual value of the first physical quantity, and controls the controlled object according to the difference between the command value and the actual value of the second physical quantity, The control unit includes a disturbance correction unit that estimates disturbances acting on the controlled object using the actual value of the first physical quantity and the actual value or command value of the second physical quantity, and corrects the command value of the second physical quantity to cancel out the estimated disturbance. The disturbance correction unit has a model for estimating the current value used for outputting the controlled object from among the current values ​​input to the controlled object. The disturbance correction unit is a control device that calculates a current disturbance value by comparing the current value estimated by the model with the current value input to the controlled object.

2. The control device according to claim 1, wherein the second physical quantity is electric current.

3. The control device according to claim 1 or 2, wherein the disturbance correction unit estimates the disturbance applied to the controlled object based on the mechanical properties of the controlled object, without considering the properties of the molding material.

4. The control device according to claim 1 or 2, wherein the disturbance correction unit estimates the disturbance using a value obtained by processing the actual value or command value of the second physical quantity with a first-order low-pass filter.

5. An injection molding machine comprising the control device according to claim 1 or 2, and the controlled object.

6. A control method comprising a control step of creating a command value for a second physical quantity different from the first physical quantity according to the difference between the command value and the actual value of the first physical quantity, and controlling the controlled object according to the difference between the command value and the actual value of the second physical quantity, The control step includes a disturbance correction step which estimates disturbances acting on the controlled object using the actual value of the first physical quantity and the actual value or command value of the second physical quantity, and corrects the command value of the second physical quantity to cancel out the estimated disturbance. The disturbance correction step uses a model that estimates the current value used for outputting the controlled object from the current value input to the controlled object. The disturbance correction step is a control method comprising the step of calculating a current disturbance value by comparing the current value estimated by the model with the current value input to the controlled object.

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