Control device, control unit, and pump system

Abstract

A control device for controlling a hydraulic pump (130) of a main machine (100) equipped with first sensors (190, 191) for detecting physical quantities of an actuator (110) includes: a flow control unit (212) for controlling the flow rate of a hydraulic fluid, a pressure control unit (211) for controlling the pressure of the hydraulic fluid, first control units (214, 216) for controlling physical quantities of an actuator (110), and a communication unit (210) for receiving first information including a target value of a physical quantity of the actuator (110) output from a main machine control unit (300) connected to the main machine (100) and the current value of the physical quantities output from the first sensors (190, 191). Necessary control is selected for each process of the main machine (100) on the basis of the first information.

Description

Control Device, Control Unit, and Pump System

[0001] The present disclosure relates to a control device, a control unit, and a pump system.

[0002] The processing device disclosed in Patent Document 1 includes a hydraulic cylinder that operates with the pressure of hydraulic oil from a hydraulic pump, and has a position sensor that detects the position of the piston rod of the hydraulic cylinder and a positioning control device that controls the position of the piston rod. The positioning control device calculates an operation amount based on the position of the piston rod detected by the position sensor and its target position. The hydraulic pump adjusts the position of the piston rod based on the operation amount.

[0003] Japanese Unexamined Patent Application Publication No. 2024-70640

[0004] The position of the piston rod indicates a physical quantity of the hydraulic cylinder. Since a control device that controls the physical quantity of an actuator such as a hydraulic cylinder is provided in the processing device separately from a pump control device that controls the pressure and flow rate of hydraulic oil, the wiring becomes complicated and the calculation processing of the operation amount also becomes complicated. For the control of such an actuator, not only the control of the physical quantity but also the control of the pressure and flow rate of the hydraulic oil are required, so there has been a demand for more convenient control of the actuator.

[0005] An object of the present disclosure is to provide a control device that can easily control an actuator driven by a hydraulic pump.

[0006] The first embodiment relates to a control device for controlling the hydraulic pump (130) of a main unit (100) which includes a hydraulic pump (130) for transporting hydraulic fluid, a motor (140) for driving the hydraulic pump (130), an actuator (110) driven by the hydraulic fluid supplied from the hydraulic pump (130), a pressure sensor (160) for detecting the pressure of the hydraulic fluid transported to the actuator (110), and first sensors (190, 191) for detecting the physical quantity of the actuator (110). The system includes a flow control unit (212) for controlling the flow rate of the hydraulic fluid, a pressure control unit (211) for controlling the pressure of the hydraulic fluid, first control units (214, 216) for controlling the physical quantities of the actuator (110), and a communication unit (210) for receiving first information including a target value for the physical quantities of the actuator (110) output from a main unit control unit (300) connected to the main unit (100) and the current value of the physical quantities output from the first sensors (190, 191). Based on the first information, the system selects the necessary control for each process of the main unit (100).

[0007] In the first embodiment, the control device (200) has a communication unit (210) that receives first information, and the first information includes information on the target value and current value of the physical quantity of the actuator (110). Therefore, the control device (200) can obtain all the information necessary to control the actuator (110) simply by receiving the first information. Having such a communication unit (210) in the control device (200) not only simplifies the installation of wiring, but also simplifies the calculation processing for controlling the physical quantity of the actuator (110) by implementing the means related to the physical quantity of the actuator (110) as software. In addition, it eliminates the need to separately provide a first control unit (214, 216) as conventional hardware, thus suppressing an increase in the manufacturing cost of the processing device.

[0008] In the second embodiment, based on the first embodiment, the flow rate control unit (212), the pressure control unit (211), and the first control unit (214, 216) are selected from among the flow rate control unit (212), the pressure control unit (211), and the first control unit (214, 216) so that the necessary control is performed for each process of the main unit (100) based on the first information.

[0009] In the second embodiment, the optimal or necessary control for various processes can be selected and executed from among flow rate control, pressure control, and physical quantity control of the actuator (110).

[0010] A third embodiment is, in the first or second embodiment, the first sensor (190, 191) is a position sensor (190) that detects the position of the actuator (110), the first control unit (214, 216) is a position control unit (214) that controls the position of the actuator (110), and the current value indicates the current position of the actuator (110).

[0011] In the third embodiment, by setting the physical quantity to the position of the actuator (110), the first control unit (214, 216) can perform position control of the actuator (110).

[0012] A fourth aspect is, in the first or second aspect, the first sensor (190, 191) is a load sensor (191) that detects the force that the actuator (110) acts on an object, the first control unit (214, 216) is a load control unit (216) that controls the force that the actuator (110) acts on an object, and the current value indicates the current force that the actuator (110) is acting on an object.

[0013] In the fourth embodiment, by defining the physical quantity as the force that the actuator (110) acts on the object, the first control unit (214, 216) can perform load control on the object by the actuator (110).

[0014] A fifth aspect is a third aspect in which the actuator (110) is controlled to perform a series of steps, and further includes a position interlocking unit (215) that controls the flow control unit (212) or the pressure control unit (211) so that when moving from one predetermined step to the next, the actuator (110) changes speed continuously and gradually.

[0015] In the fifth embodiment, the position interlocking unit (215) allows the actuator (110) to operate smoothly between consecutive steps when the actuator (110) decelerates or accelerates, or when the hydraulic fluid pressure increases or decreases. For example, if the actuator (110) is a hydraulic cylinder (110) having a rod (113), setting the target flow rate at the target position to zero allows the actuator (110) to decelerate continuously and gradually, and to align with the target position. This improves the stopping position accuracy of the rod (113), suppresses the sudden stopping of the rod (113) at the end of a step, and reduces the generation of vibrations when the rod (113) stops suddenly.

[0016] In the sixth aspect, as in the fifth aspect, the position interlocking unit (215) interpolates the step change of the target flow rate or target pressure of the hydraulic fluid in proportion to the amount of movement of the actuator (110) when transitioning from a predetermined step to the next step.

[0017] In the sixth embodiment, for example, if the actuator (110) is a hydraulic cylinder (110) having a rod (113), interpolation performed by the position linkage unit (215) can suppress the shift in the stopping position of the rod (113) relative to the target position when transitioning from a deceleration step to a stopping step of the rod (113).

[0018] The seventh embodiment is a control unit comprising one of the control devices (200) of the first to sixth embodiments and the main unit control unit (300).

[0019] In a seventh aspect, a control unit comprising a control device (200) and a main unit control unit (300) can be provided.

[0020] The eighth aspect is a pump system comprising a pump unit (500) including one of the hydraulic pumps (130), the motor (140), and the pressure sensor (160) according to any one of the first to sixth aspects, and the control device (200).

[0021] In the eighth aspect, a pump system can be provided that has a control device that can easily control the position of the actuator (110).

[0022] Figure 1 is a schematic block diagram of a processing apparatus equipped with a pump control device according to an embodiment. Figure 2 is a diagram illustrating the switching of the direction switching section. Figure 3 is a diagram illustrating the operation of the processing apparatus in each step of the press. Figure 4 is a graph illustrating the method of deceleration and stopping of the rod by rod position linkage. Figure 5 is a schematic block diagram corresponding to Figure 1 of a processing apparatus equipped with a pump control device according to a modified example. Figure 6 is a diagram corresponding to Figure 3 showing the operation of the processing apparatus in each step of the press according to a modified example. Figure 7 is a schematic block diagram corresponding to Figure 1 of a processing apparatus equipped with a pump control device according to another embodiment. Figure 8 is a schematic block diagram corresponding to Figure 1 of a processing apparatus equipped with a pump control device according to another embodiment.

[0023] Embodiments of the present invention will be described below with reference to the drawings. The following embodiments are essentially preferred examples and are not intended to limit the scope of the present invention, its applications, or its uses. Furthermore, the embodiments, modifications, and other examples described below can be combined or partially replaced to the extent that the present invention is implementable.

[0024] 《Embodiment》 (1) Overall configuration of the processing device The processing device (1) shown in Figure 1 has a main machine (100) and a pump control device (200). The processing device (1) is a press machine for forming industrial parts such as mechanical gears. The press machine forms press materials such as metal, rubber, and resin into predetermined shapes and dimensions by compressing them. Generally, high dimensional accuracy is required for forming industrial parts such as mechanical gears in a press machine.

[0025] (2) Main engine The main engine (100) comprises a tank (150), a hydraulic pump (130), a hydraulic cylinder (110), a mold (400), a direction switching unit (120), a relief valve (170), a motor (140), a rotation sensor (180), a pressure sensor (160), and a position sensor (190).

[0026] The main engine (100) has a circuit (125) consisting of oil piping through which hydraulic fluid flows. The circuit (125) includes a hydraulic cylinder (110), a tank (150), a hydraulic pump (130), a mold (400), a directional switch (120), and a relief valve (170). The circuit (125) is configured so that the hydraulic fluid moves back and forth between the tank (150) and the hydraulic cylinder (110). The oil piping includes a first upper pipe (121), a second upper pipe (122), a first lower pipe (123), and a second lower pipe (124).

[0027] (2-1) Tank Tank (150) stores hydraulic fluid. One end of the first lower pipe (123) and one end of the second lower pipe (124) are connected to the tank (150). One end of the second lower pipe (124) is the suction port of the hydraulic pump (130).

[0028] (2-2) Hydraulic pump The hydraulic pump (130) transports the hydraulic fluid. The hydraulic pump (130) in this embodiment is a unidirectional pump that rotates in one direction. The hydraulic pump (130) is connected to the second lower piping (124). The hydraulic pump (130) discharges the oil drawn up from the tank (150) to the second lower piping (124).

[0029] (2-3) Hydraulic Cylinder The hydraulic cylinder (110) in this embodiment is a single-rod hydraulic cylinder. The hydraulic cylinder (110) is driven by hydraulic fluid supplied from a hydraulic pump (130). The hydraulic cylinder (110) comprises a cylinder section (111), a piston (112), and a rod (113). The piston (112) and rod (113) housed in the cylinder section (111) move together in the vertical direction. The cylinder section (111) has a first port (P1) to which one end of the first upper pipe (121) is connected, and a second port (P2) to which one end of the second upper pipe (122) is connected. The hydraulic cylinder (110) is an example of an actuator. "Actuator position" includes the case where it is the position of one element of the movable part constituting the actuator. In this embodiment, the actuator position indicates the position of the rod (113), which is a movable part constituting the hydraulic cylinder (110). The actuator position is an example of a physical quantity of this disclosure. In other words, the position of the rod (113) is an example of a physical quantity of the hydraulic cylinder (110).

[0030] Hydraulic fluid flows into and out of the cylinder section (111) through a first port (P1) and a second port (P2). The first port (P1) is located in the head-side space (S1) of the cylinder section (111). The second port (P2) is located in the rod-side space (S2) of the cylinder. The piston (112) is integrated with the rod (113) and housed within the cylinder section (111).

[0031] The piston (112) slides along the inner wall of the cylinder section (111) between the first port (P1) and the second port (P2) and moves vertically. The piston (112) divides the space within the cylinder section (111) into a head-side space (S1) and a rod-side space (S2). The vertical movement of the piston (112) changes the spatial volume of the head-side space (S1) and the rod-side space (S2).

[0032] One end of the rod (113) is fixed to the piston (112), and the other end is fixed to the upper mold (410), which will be described later. The rod (113) moves vertically together with the piston (112). The position of the rod (113) indicates its position in the vertical direction. In the following description, the downward movement of the rod (113) is sometimes referred to as forward movement, and the upward movement of the rod is sometimes referred to as backward movement.

[0033] (2-4) The die (400) is positioned below the hydraulic cylinder (110). The die (400) has an upper die (410) and a lower die (420). The upper die (410) is connected to a rod (113). This allows the upper die (410) to move vertically. The lower die (420) is fixed below the upper die (410). The workpiece in this embodiment is a press material. The press material is pressed between the upper die (410) and the lower die (420). The press material is the subject of this disclosure.

[0034] (2-5) Directional switching section As shown in Figure 1, the directional switching section (120) is provided between the hydraulic pump (130) and the hydraulic cylinder (110) and switches the direction of the hydraulic fluid flow. One end of each of the first upper pipe (121), first lower pipe (123), second upper pipe (122), and second lower pipe (124) is connected to the directional switching section (120).

[0035] The direction switching unit (120) can be switched to a first state, a second state, and a stopped state. As shown in Figure 2, in the first state, the second upper pipe (122) and the first lower pipe (123) are in communication, and the first upper pipe (121) and the second lower pipe (124) are in communication (Figure 2(a)). In the second state, the first upper pipe (121) and the first lower pipe (123) are in communication, and the second upper pipe (122) and the second lower pipe (124) are in communication (Figure 2(b)). In the stopped state, the first upper pipe (121), the second upper pipe (122), and the first lower pipe (123) are in communication (Figure 1), and the second lower pipe (124) is disconnected from the circuit (125).

[0036] In the first state, the hydraulic fluid drawn up from the tank (150) to the second lower piping (124) flows into the head-side space (S1) via the first upper piping (121), while the hydraulic fluid in the rod-side space (S2) flows into the tank (150) via the second upper piping (122), the relief valve (170), and the first lower piping (123). As a result, the pressure of the hydraulic fluid acts downward on the piston (112), causing the piston (112) and the rod (113) to move downward.

[0037] On the other hand, in the second state, the hydraulic fluid drawn up from the tank (150) to the second lower pipe (124) flows into the rod-side space (S2) via the check valve (CV) and the second upper pipe (122), while the hydraulic fluid in the head-side space (S1) flows into the tank (150) via the first upper pipe (121) and the first lower pipe (123). As a result, the pressure of the hydraulic fluid acts upward on the piston (112), causing the piston (112) and the rod (113) to move upward.

[0038] (2-6) Relief valve The relief valve (170) is installed in the second upper piping (122). Specifically, the relief valve (170) is installed to bypass the check valve (CV) installed in the second upper piping (122). The relief valve (170) is set to the minimum pressure that can prevent the piston (112) from descending under its own weight due to the weight of the upper mold (410). The check valve (CV) allows the hydraulic fluid in the second upper piping (122) to flow toward the rod side space (S2) and restricts the flow in the opposite direction. As a result, when the piston (112) tries to move downward, the hydraulic fluid in the second upper piping (122) flows through the relief valve (170). The check valve (CV) and the relief valve (170) are integrated and function as a counterbalancing valve.

[0039] (2-7) Motor The motor (140) drives the hydraulic pump (130). The motor (140) is a servo motor. The motor (140) is controlled by a rotation command output from the calculation selection unit (213). Normally, the motor (140) rotates to cause the hydraulic fluid in the second lower pipe (124) to flow toward the hydraulic cylinder (110), but when it is necessary to reduce the pressure of the hydraulic fluid in the second lower pipe (124), it can temporarily rotate in the reverse direction to cause the hydraulic fluid in the second lower pipe (124) to flow backward into the tank (150).

[0040] (2-8) Rotation Sensor The rotation sensor (180) detects the rotation speed of the motor (140). The rotation speed of the motor (140) indicates the flow rate of the hydraulic fluid. The rotation sensor (180) transmits the detected value of the rotation speed of the motor (140) to the flow control unit (212). The flow rate of the hydraulic fluid corresponds to the discharge flow rate of the hydraulic fluid from the hydraulic pump (130).

[0041] (2-9) Pressure Sensor The pressure sensor (160) detects the pressure of the hydraulic fluid being transported to the hydraulic cylinder (110). Specifically, the pressure sensor (160) is connected to the second lower piping (124) and detects the pressure of the hydraulic fluid being transported to the hydraulic cylinder (110) when the direction switching unit (120) is in operation. During the pressing process, it reflects the pressure applied to the press material. During the rod (113) raising process, it reflects the weight of the mold. Hereinafter, the pressure of the hydraulic fluid may be simply referred to as "pressure". The pressure sensor (160) transmits the detected pressure value to the pressure control unit (211).

[0042] (2-10) Position Sensor The position sensor (190) is an example of the first sensor of the present disclosure. The position sensor (190) detects the position of the hydraulic cylinder (110). Specifically, the position sensor (190) detects the current position of the rod (113). The current position of the rod (113) indicates the current value of the physical quantity of the present disclosure. The position sensor (190) outputs information indicating the current position of the rod (113). The information indicating the current position of the rod (113) is included in the first information of the present disclosure. Note that at the bottom dead center of the press process, the processing dimensions of the processed material can be grasped by detecting the current position of the rod (113). The position sensor (190) inputs the position information of the rod (113) to the host control unit (300).

[0043] (3) Host Control Unit The processing device (1) has a host control unit (300). The host control unit (300) is composed of a programmable logic controller (PLC). The host control unit (300) is provided with a microcomputer and a memory device for storing software for operating the microcomputer. The host control unit (300) is connected to the host (100) by wire. The host control unit (300) transmits a predetermined command to the pump control device (200).

[0044] The host control unit (300) has a position sensor conversion unit (310). After receiving the current position information of the rod (113) from the position sensor (190) as an electrical signal, the position sensor conversion unit (310) converts it into predetermined numerical information and transmits it to the software of the host control unit (300). The host control unit (300) controls the direction switching unit (120).

[0045] The host control unit (300) is connected to the pump control device (200) by wire or wirelessly. For example, the host control unit (300) and the pump control device (200) are connected by industrial high-speed communication. The host control unit (300) has a host communication unit (320) and transmits a predetermined signal to the pump control device (200). The predetermined signal includes the first information described later. The predetermined command transmitted by the host control unit (300) to the pump control device (200) includes the first information.

[0046] (4) Pump control device The pump control device (200) is an example of the control device of the present disclosure. The pump control device (200) controls the hydraulic pump (130). The pump control device (200) is communicably connected to the main machine control unit (300) of the main machine (100). The pump control device (200) is provided with a microcomputer and a memory device for storing software for operating the microcomputer. The pump control device (200) selects the necessary control for each process of the main machine (100) based on the first information. Although details will be described later, the pump control device (200) of the present embodiment selects from the flow control unit (212), the pressure control unit (211), and the position control unit (214) so that the necessary control for each process of the main machine (100) is executed based on the first information.

[0047] The pump control device (200) includes a communication unit (210), a position control unit (214), a flow control unit (212), a pressure control unit (211), an arithmetic selection unit (213), and a position linkage unit (215).

[0048] (4-1) Communication unit The communication unit (210) receives the first information output from the main machine communication unit (320) of the main machine control unit (300). The first information includes information on the current position and the target position of the rod (113). The target position of the rod (113) is an example of the target value of the physical quantity of the present disclosure. Further, the first information includes information indicating the target flow rate and the target pressure of the hydraulic oil. 7>

[0049] The target flow rate corresponds to the speed at which the rod (113) moves to the target position. The target pressure corresponds to the pressure at which the rod (113) compresses the press material. The target position, the target flow rate, and the target pressure of the rod (113) are set over the entire press process.

[0050] The communication unit (210) transmits an arithmetic selection signal. The arithmetic selection signal is a signal for instructing the selection from the flow control unit (212), the pressure control unit (211), and the position control unit (214) of the necessary control for each process of the main machine (100) based on the first information. The communication unit (210) transmits the information indicating the current position and the target position of the rod (113), the target flow rate, and the target pressure included in the first information.

[0051] (4-2) Position Control Unit The position control unit (214) is an example of the first control units (214, 216) of this disclosure. The position control unit (214) controls the position of the rod (113). Specifically, the position control unit (214) controls the movement of the rod (113) based on the target position and current position of the rod (113). The position control unit (214) calculates a first output value based on information (first information) received by the communication unit (210) that includes the current position and target position of the rod (113). The first output value indicates an operation amount that causes the current position of the rod (113) to follow the target position. For example, at the bottom dead center of the press, the operation amount is calculated to maintain a constant thickness of the workpiece. The first output value may be output continuously in a predetermined process.

[0052] (4-3) Flow Control Unit The flow control unit (212) controls the movement speed of the rod (113) so that the current flow rate of the hydraulic fluid becomes the target flow rate. The flow control unit (212) calculates a second output value based on the value detected by the rotation sensor (180) and the target flow rate output by the communication unit (210). In this embodiment, the flow control unit (212) calculates a second output value based on the internal target flow rate output from the first position interlocking unit (215a), which will be described later, and the value detected by the rotation sensor (180). The second output value is output continuously in a predetermined process. The internal target flow rate will be described later.

[0053] (4-4) Pressure Control Unit The pressure control unit (211) controls the thrust of the rod (113) so that the current pressure of the hydraulic fluid becomes the target pressure. The pressure control unit (211) calculates a third output value based on the value detected by the pressure sensor (160) and the target pressure output by the communication unit (210). In this embodiment, the pressure control unit (211) calculates a third output value based on the internal target pressure output from the second position interlocking unit (215b), which will be described later, and the value detected by the pressure sensor (160). The third output value is output continuously in a predetermined process. The internal target pressure will be described later.

[0054] (4-5) Calculation Selection Unit The calculation selection unit (213) selects one of the output values ​​output from the position control unit (214), the flow rate control unit (212), and the pressure control unit (211). Specifically, the calculation selection unit (213) selects one of the first output value, the second output value, or the third output value based on the calculation selection signal output from the communication unit (210). The calculation selection unit (213) outputs the selected output value to the motor (140) as a rotation command value.

[0055] (4-6) Position-linked section The position-linked section (215) calculates the internal target flow rate and the internal target pressure. The internal target flow rate is calculated to change gradually in conjunction with the position so that when the rod's current position reaches the new target position when moving from one predetermined step to the next, the new target flow rate is reached. The internal target pressure is calculated to change gradually in conjunction with the position so that when the rod's current position reaches the new target position when moving from one predetermined step to the next, the new target pressure is reached.

[0056] The position-linked unit (215) interpolates the step change in the target flow rate or target pressure of the hydraulic fluid in proportion to the amount of movement of the rod (113) so that the moving rod (113) changes speed continuously and smoothly when moving from one predetermined step to the next. The amount of movement is defined, for example, by the difference between the target position and the current position of the rod (113). In other words, in press working, the position-linked unit (215) interpolates the step change in the target flow rate or target pressure of the hydraulic fluid in proportion to the difference between the target position and the current position of the rod (113). Specifically, when moving from one predetermined step to the next, the flow rate control unit (212) or pressure control unit (211) is controlled so that the response until the rod (113) is located at the target position is continuous by modifying the target flow rate or target pressure of the next step in conjunction with the movement of the moving rod (113). The position-linked unit (215) has a first position-linked unit (215a) and a second position-linked unit (215b).

[0057] The first position interlocking unit (215a) receives position information from the communication unit (210) indicating the current position and target position of the rod (113), as well as information indicating the target flow rate. Based on this received information, the first position interlocking unit (215a) calculates the internal target flow rate and transmits the calculated internal target flow rate to the flow rate control unit (212).

[0058] The second position interlocking unit (215b) receives information from the communication unit (210) indicating the current position and target position of the rod (113), as well as information indicating the target pressure. Based on the received information, the second position interlocking unit (215b) calculates the internal target pressure and transmits the calculated internal target pressure to the pressure control unit (211).

[0059] Thus, since the internal target flow rate and internal target pressure are target values ​​that take position control into consideration, for example, the flow control unit (212) controls the movement of the rod (113) based on the internal target flow rate. When transitioning from the step of decelerating the rod (113) to the waiting step, the rod (113) gradually and continuously decelerates toward the waiting step and stops at the target position at the start of the waiting step. Specifically, when the target stopping position of the rod (113) and the target flow rate of the hydraulic fluid are input as zero, the rod (113) decelerates as it approaches the stopping position and its speed becomes zero at the stopping position.

[0060] (5) Operation of the Processing Apparatus The operation of the processing apparatus (1) in this embodiment will be explained with reference to Figure 3. The processing apparatus (1) is controlled so that the rod (113) of the hydraulic cylinder (110) performs a series of steps. The series of steps includes a standby step, a lowering step, a holding pressure step, a pressure relief step, and an upward step. In the press working of this embodiment, the standby step, lowering step, holding pressure step, pressure relief step, upward step, and standby step are performed in order. When forming multiple press materials in succession, this series of steps is performed repeatedly.

[0061] The series of movements of the rod in the pressing process shown in Figure 3 are stored in the main unit control unit (300) as a pre-designed program. The series of movements of the rod (113) may also be designed by a predetermined controller provided in the main unit control unit (300).

[0062] In each step, the main unit control unit (300) transmits first information to the communication unit (210). In each step, the rotation of the motor (140) is controlled based on the first information input to the communication unit (210).

[0063] (5-1) Standby Step During the standby step, the rod (113) is maintained in its most retracted position (highest position) (Figure 3(i)). Specifically, the main engine control unit (300) stops the direction switching unit (120). As a result, no hydraulic fluid flows through the circuit (125), and the rod (113) remains stationary in its most retracted position.

[0064] (5-2) Lowering Step In the lowering step, the main engine control unit (300) switches the direction switching unit (120) from the stopped state to the first state. Due to the rotation of the motor (140), the hydraulic fluid in the tank (150) flows into the head-side space (S1) via the second lower pipe (124) and the first upper pipe (121), and the hydraulic fluid in the rod-side space (S2) flows into the tank (150) via the second upper pipe (122) and the first lower pipe (123). As a result, the piston (112) moves downward and the rod (113) descends.

[0065] In the descent step, the following steps are executed in order: an accelerated descent step (Figure 3(ii)), a high-speed descent step (Figure 3(iii)), and a decelerated descent step (Figure 3(iv)).

[0066] The acceleration descent step is a step in which the rod (113) is accelerated until it reaches a predetermined position from a standby position. During the acceleration descent step, the rotation of the motor (140) is controlled by flow rate control. Specifically, the calculation selection unit (213) selects a second output value based on the calculation selection signal. Based on the second output value, the rotation speed of the motor (140) is controlled, and the rod (113) is accelerated to reach a target speed at the acceleration completion position.

[0067] The high-speed descent step is a step in which the flow rate of the hydraulic fluid is maintained at a constant level. When the position sensor (190) detects that the rod (113) has reached a predetermined position, the calculation selection unit (213) selects a second output value based on the calculation selection signal. Based on the second output value, the rotational speed of the motor (140) is controlled, and the rod (113) is indirectly accelerated so that its current position follows the change in the target position. In this way, the target flow rate remains constant until the rod (113) reaches the deceleration start position, and the rod (113) descends at a constant speed.

[0068] The deceleration descent step is a step in which the rod (113) is decelerated from a predetermined position until it reaches a position where the upper die (410) contacts the press material. During the deceleration descent step, the rotation of the motor (140) is controlled by flow rate control. The calculation selection unit (213) selects a second output value based on the calculation selection signal. Based on the second output value, the rod (113) is decelerated to reach a target speed at the deceleration completion position.

[0069] (5-3) Compression Step In the compression step, the press material is compressed by the upper die (410) to a predetermined shape (Figure 3(v)). In the compression step, the rotation of the motor (140) is controlled by flow rate control. Specifically, the calculation selection unit (213) selects a second output value based on the calculation selection signal.

[0070] When the upper die (410) comes into contact with the press material, processing pressure is generated. As the load pressure increases, the rotational speed of the motor (140) decreases, and the downward speed of the rod (113) tends to decrease. However, because the flow control unit (212) provides feedback on the rotational speed of the motor (140), the flow rate of the hydraulic fluid is controlled to remain constant based on the second output value. As a result, the motor rotation is maintained at the speed of the low-speed process. When the position sensor (190) detects that the rod (113) has reached the bottom dead center, the process moves to the holding pressure step.

[0071] (5-4) Holding Pressure Step The holding pressure step is a step in which the rod (113) is stopped at the target position for a certain period of time while the press material is compressed (Figure 3 (vi)). In the holding pressure step, the rotation of the motor (140) is controlled by the pressure of the hydraulic fluid. Specifically, the calculation selection unit (213) selects a third output value based on the calculation selection signal. The third output value at this time indicates the manipulated amount calculated so that the rod (113) generates a thrust equivalent to the target pressure. Based on the third output value, the rotation speed of the motor (140) is adjusted so that a current pressure equal to the manipulated amount is generated compared to the target pressure. As a result, the rotation speed of the motor (140) is maintained at almost zero. However, a reaction force (upward force) from the press material acts on the upper die (410), so the rod (113) tries to move backward as it is pushed by the press material. For this reason, the rotation speed of the motor (140) is not simply stopped, but generates torque that can maintain the target pressure against the load pressure. In the holding pressure step, simply maintaining the pressure is insufficient, as variations in the amount and temperature of the compressed material will result in variations in the processed dimensions of the material. Therefore, in the precision press machine (processing device (1)), the rod (113) is positioned with an accuracy of several micrometers near the target position. The holding pressure step may also include a precision holding pressure step (Figure 3 (vii)). In the precision holding pressure step, the rotation of the motor (140) is controlled by the position control of the rod (113). The calculation selection unit (213) selects a first output value based on the calculation selection signal. In the precision holding pressure step, the rod (113) is controlled to stop at the target position by changing the pressure of the hydraulic fluid.

[0072] (5-5) Pressure Release Step The pressure release step is a step in which the current pressure of the hydraulic fluid generated in the pressure holding step is reduced to zero (Figure 3 (viii)). The calculation selection unit (213) selects a third output value based on the calculation selection signal. No position-based linked calculation is performed in the pressure release step. Specifically, the target position is set to a negative value outside the movement range, and in this case, the target pressure is output as is as the internal target pressure. On the other hand, if the main engine control unit (300) is set to gradually reduce the target pressure to zero, the pressure control unit (211) calculates a negative value for the manipulated amount because the internal target pressure becomes smaller than the value detected from the input pressure sensor (160). As a result, the motor rotation reverses, and the hydraulic fluid compressed on the cylinder head side is returned to the tank (150) by the reverse-rotating hydraulic pump (130), causing the pressure to decrease. In other words, although the input to the pressure control unit (211) is limited to positive values, the calculation result can be reversed to positive or negative. In other words, during the positioning and holding pressure step, the rotation speed of the motor (140) is kept at almost zero while a predetermined positive current pressure is generated. Then, during the pressure relief step, as the current pressure decreases until it reaches zero, the rotation speed of the motor (140) also decreases. However, because it decreases from an almost zero state, the motor (140) ends up rotating in the reverse direction. When the current pressure reaches zero, the rotation speed of the motor (140) returns to zero, and the pressure relief step ends. At the end of the pressure relief step, the direction switching unit (120) is switched to the stop state, and it temporarily enters a standby state in preparation for the next step.

[0073] (5-6) Lifting Step The lifting step is a step in which the rod (113) is retracted to the standby position. During the lifting step, the main engine control unit (300) switches the direction switching unit (120) from the stopped state to the second state (b). During the lifting step, the hydraulic fluid in the head-side space (S1) flows into the tank (150) via the first upper pipe (121) and the first lower pipe (123), and at the same time, the hydraulic fluid in the tank (150) flows into the rod-side space (S2) via the second lower pipe (124) and the second upper pipe (122). As a result, the piston (112) rises together with the rod (113). A load pressure is generated on the piston (112) mainly due to the weight of the upper mold, but the lifting speed of the rod (113) is maintained by selecting the flow rate control unit (212) and feedback-controlling the rotation speed of the motor.

[0074] In the ascent step, the accelerating ascent step (Figure 3 (ix)), the high-speed ascent step (Figure 3 (x)), and the decelerating ascent step (Figure 3 (xi)) are executed in order.

[0075] The acceleration-up step is a step in which the rod (113) is accelerated until it reaches a predetermined position from its bottom dead center. During the acceleration-up step, the rotational speed of the motor (140) is controlled by flow rate control. Specifically, the calculation selection unit (213) selects a second output value based on the calculation selection signal. Based on the second output value, the rotational speed of the motor (140) is controlled, and the rod (113) is accelerated to reach a target speed at the acceleration completion position.

[0076] The high-speed ascent step is a step in which the flow rate of the hydraulic fluid is maintained at a constant level. When the position sensor (190) detects that the rod (113) has reached a predetermined position, the calculation selection unit (213) selects a second output value based on the calculation selection signal. Based on the second output value, the rotation of the motor (140) is controlled so that the speed of the rod (113) is maintained at a high level. That is, the target flow rate remains constant until the rod (113) reaches the deceleration start position, and the rod (113) rises at a constant speed.

[0077] The deceleration-up step is a step in which the rod (113) is decelerated until it reaches a standby position from a predetermined position. In the deceleration-up step, the rotation of the motor (140) is controlled by flow rate control. Specifically, the calculation selection unit (213) selects a second output value based on the calculation selection signal, and the rotation speed of the motor (140) is controlled based on the second output value, so that the rod (113) is decelerated to reach a target speed of zero at the standby position.

[0078] When the rod (113) reaches the standby position, the standby step is executed again (Figure 3 (xii)). Specifically, the main engine control unit (300) sets the target flow rate and target pressure to zero, and switches the direction switching unit (120) to the stop state. As a result, the rod stops and the motor speed is controlled to zero. Also, because the pressure command value is zero, the motor's rotational torque and the hydraulic fluid pressure are both zero. In practice, however, in the standby state, the target pressure is often set slightly to apply a small amount of pre-pressure to prevent the generation of air bubbles in the piping.

[0079] (6) Features (6-1) Feature 1 The pump control device (200) of this embodiment includes a flow control unit (212) that controls the flow rate of the hydraulic fluid, a pressure control unit (211) that controls the pressure of the hydraulic fluid, a position control unit (214) that controls the position of the rod (113), and a communication unit (210) that receives first information including information on the target position and current position of the rod (113) output from the main engine control unit (300). Based on the first information, the pump control device (200) selects the necessary control for each process of the main engine (100).

[0080] According to this embodiment, since the pump control device (200) has a communication unit (210) that receives first information, and the first information includes target position and current position information of the rod (113), the pump control device (200) can easily control the main unit (100) simply by receiving the first information, and consequently simplify the position control of the rod (113). With such a communication unit (210), not only is the installation of wiring simplified, but the calculation processing for controlling the physical quantities of the hydraulic cylinder (110) can be simplified by implementing means related to the physical quantities of the hydraulic cylinder (110) as software. In addition, since it is not necessary to separately provide a first control unit (214, 216) as conventional hardware, the increase in manufacturing costs of the processing device can be suppressed.

[0081] (6-2) Feature 2 The pump control device (200) of this embodiment selects from the flow rate control unit (212), pressure control unit (211), and position control unit (214) so ​​that the necessary control is executed for each process of the main unit (100). This allows for free selection and control of flow rate control, pressure control, and position control. The communication unit (210) receives first information including information on the target position and current position of the rod (113) output from the main unit (100), and outputs a predetermined signal to select the necessary control for each process of the main unit (100) from the flow rate control unit (212), pressure control unit (211), and position control unit (214). In this way, the pump control device (200) can select from the flow rate control unit (212), pressure control unit (211), and position control unit (214) so ​​that the necessary control is executed for each process of the main unit (100).

[0082] (6-3) Feature 3 In this embodiment, when moving from a predetermined step to the next step, the moving rod (113) changes speed continuously and smoothly, and the step change in the target flow rate or target pressure of the hydraulic fluid is further interpolated in proportion to the amount of movement of the rod (113).

[0083] The position-linking unit (215) calculates an internal target flow rate or internal target pressure, which allows the movement of the rod (113) to be gradually accelerated or decelerated toward the target position. This improves the accuracy of the stopping position of the rod (113) when decelerating and stopping toward the standby position by setting the standby position and target speed to zero at the deceleration start position. In particular, when transitioning from the deceleration descent step to the compression step, the movement of the rod (113) is gradually decelerated toward the target position. Therefore, if a low speed target value is set toward the position where the upper die touches the actual material, the compression of the material begins simultaneously with the completion of deceleration, thus shortening the cycle time. Because the rod (113) moves smoothly in this way, abrupt stops at the end of the deceleration step are suppressed, and the generation of vibrations that occur when the rod (113) stops abruptly can be reduced.

[0084] Here, we will explain the rod deceleration method using Figure 4. In a typical rod deceleration method, a rod (113) moving at high speed transitions to a deceleration upward step when it reaches a predetermined position X1 based on the target flow rate Q1, and is controlled so that the flow rate becomes zero after a preset deceleration time TS has elapsed from the time it reaches the predetermined position X1. As a result, the rod (113) can be decelerated during the deceleration time TS and stop without shock. However, in this deceleration method, the flow rate becomes zero after the deceleration time TS has elapsed, but the rod (113) does not stop at the standby position X2 every time, so the stopping position of the rod (113) varies. In other words, the standby position X2 cannot be set directly from the main engine control unit (300). Furthermore, the standby position X2 is also unstable due to the variation in deceleration time.

[0085] Therefore, the pump control device (200) of this embodiment has a position interlocking unit (215) that calculates an internal target flow rate or internal target pressure. Specifically, the first position interlocking unit (215a) receives input of a stop position X2 and a target flow rate of zero at the deceleration start position X1 of the rod (113), and calculates an internal target flow rate Q2 in which the current flow rate Q1 gradually becomes zero as the rod (113) approaches the stop position X2.

[0086] The flow control unit (212) controls the operation of the motor (140) based on the internal target flow rate Q2 and the current rotational speed of the motor (140). When the position sensor (190) detects that the rod (113) has reached a predetermined position X1, the first position interlocking unit sets a standby position X2 and a standby speed of zero, thereby gradually decreasing the internal target flow rate in conjunction with the subsequent position change, and stopping when the flow rate becomes zero when the rod (113) reaches X2.

[0087] Thus, even if the deceleration time TS varies due to motor rotation response or cylinder friction, the rod (113) continuously and gradually decelerates during the deceleration upward step and stops at the standby position X2. Similarly, during the deceleration downward step, when the position sensor (190) detects that the rod (113), which is descending at high speed, has reached the deceleration start position, the deceleration downward step is executed, and the rod is decelerated to the optimal set speed for compressing the press material at the deceleration completion position where the upper die (410) contacts the press material. In addition, since the compression of the material can be started simultaneously, there is no need to have a low-speed idle section, and the cycle time can be shortened.

[0088] 《Modified Version》 (7) Processing Apparatus As shown in Figure 5, the modified processing apparatus (1) controls the load of the hydraulic cylinder (110) acting on the press material instead of the position control of the above embodiment. Due to friction etc. that occurs when the rod (113) moves within the cylinder part (111), the thrust efficiency converted from hydraulic pressure to cylinder thrust decreases. In this modified version, the load on the press material by the rod is feedback controlled in the holding pressure step. In other words, the precision holding pressure step of this modified version is performed by controlling the load on the press material by the rod. The following will mainly describe the configuration of the modified processing apparatus (1) that differs from the processing apparatus of the above embodiment.

[0089] The main unit (100) has a load sensor (191). The load sensor (191) is an example of the first sensor (191) of this disclosure. The load sensor (191) of this modified example detects the force that the hydraulic cylinder (110) exerts on the press material. Specifically, the load sensor (191) is a so-called load cell that converts the force (load, torque, etc.) exerted by the rod (113) on the press material via the upper die (410) into an electrical signal. The force exerted by the hydraulic cylinder (110) on the press material is an example of a physical quantity of this disclosure. The load sensor (191) converts a current value indicating the current force (current value) acting on the press material into an electrical signal and transmits it to the main unit control unit (300). The main unit (100) of this modified example also has a position sensor (190) that detects the position of the rod (113). In this modified example, the position sensor (190) is not the first sensor of this disclosure. The position sensor (190) transmits an electrical signal indicating the position of the detected rod (113) to the position sensor conversion unit (310) of the main unit control unit (300). The information indicating the position of the rod (113) is used for switching steps in the operation of the processing apparatus (1). The information indicating the position of the rod (113) is not included in the first information of this modified example.

[0090] The main control unit (300) includes a load sensor conversion unit (311). The load sensor conversion unit (311) receives the current value of the rod (113) from the load sensor (191) as an electrical signal, converts it into predetermined numerical information, and transmits it to the software of the main control unit (300).

[0091] The pump control device (200) comprises a communication unit (210), a flow rate control unit (212), a pressure control unit (211), a load control unit (216), and a calculation selection unit (213). The first information in this modified example includes the target value of the force that the rod (113) exerts on the press material, and the current value output from the load sensor (191). The pump control device (200) in this modified example selects either the flow rate control unit (212) or the pressure control unit (211) based on the first information so that the necessary control is performed for each process of the main engine (100). Specifically, the communication unit (210) transmits a calculation selection signal to the calculation selection unit (213). The calculation selection signal is a signal that instructs the selection of the necessary control for each process of the main engine (100) from either the flow rate control unit (212) or the pressure control unit (211). The communication unit (210) outputs information indicating the current value and target value of the rod (113) included in the first information, and the target flow rate of the hydraulic fluid.

[0092] The flow control unit (212) calculates a fourth output value based on the value detected by the rotation sensor (180) and the target flow rate output by the communication unit (210).

[0093] The load control unit (216) controls the force acting on the press material of the rod (113). Specifically, the load control unit (216) receives the current value and target value of the rod (113) output from the communication unit (210) and calculates a fifth output value based on them. The fifth output value may be calculated so that, for example, the thickness of the press material is kept constant at the bottom dead center of the press. The load control unit (216) transmits the fifth output value to the pressure control unit (211). The fifth output value may be output continuously in a predetermined process.

[0094] The pressure control unit (211) calculates a sixth output value based on the value detected by the pressure sensor (160) and the fifth output value. The sixth output value is output continuously in a predetermined process.

[0095] The calculation selection unit (213) selects one of the output values ​​output from the flow rate control unit (212) and the pressure control unit (211). Specifically, the calculation selection unit (213) selects either the fourth output value or the sixth output value based on the calculation selection signal output from the communication unit (210). The calculation selection unit (213) outputs the selected output value to the motor (140) as a rotation command value.

[0096] (8) Operation of the Processing Apparatus The operation of the modified processing apparatus (1) will be explained using Figure 6. The modified processing apparatus (1) has a standby step, a lowering step, a holding pressure step, a pressure release step, and an upward step, similar to the embodiment described above. The following will mainly explain the differences from the operation of the processing apparatus of the embodiment described above.

[0097] The descent step consists of a first low-speed descent step (Figure 6(ii)), a high-speed descent step (Figure 6(iii)), and a second low-speed descent step (Figure 6(iv)), which are executed in order. In the first low-speed descent step, the rod (113) descends from the standby position to the high-speed switching position. In the high-speed descent step, the rod (113) descends from the high-speed switching position to the low-speed switching position. In the second low-speed descent step, the rod (113) descends from the low-speed switching position to the deceleration completion position.

[0098] The high-speed descent step is the same as the high-speed descent step of the operation of the processing apparatus (1) in the above embodiment. In the first and second low-speed descent steps, the rotation of the motor (140) is controlled by flow rate control. In the first and second low-speed descent steps, the flow rate of the hydraulic fluid is kept constant. Specifically, in the first and second low-speed descent steps, the target flow rate is determined based on the fourth output value. The target flow rate in the first low-speed descent step is lower than the target flow rate in the high-speed descent step. In the first and second low-speed descent steps, the rotational speed of the motor (140) is controlled based on the target flow rate, and the rod (113) descends at a constant speed.

[0099] In the precision holding pressure step of this modified example (Figure 6(vii)), the rotation of the motor (140) is controlled by load control. Load control is the control of the force that the rod (113) exerts on the press material. Specifically, the calculation selection unit (213) selects a sixth output value based on the calculation selection signal. The rotation speed of the motor is controlled based on the sixth output value so that the load on the press material is maintained at the target load until the end of the precision holding pressure step.

[0100] The ascent step consists of a first low-speed ascent step (Figure 6(ix)), a high-speed ascent step (Figure 6(x)), and a second low-speed ascent step (Figure 6(xi)), performed in order. In the first low-speed ascent step, the rod (113) rises from the bottom dead center to the high-speed switching position. In the high-speed ascent step, the rod (113) rises from the high-speed switching position to the low-speed switching position. In the second low-speed ascent step, the rod (113) rises from the low-speed switching position to the standby position.

[0101] The high-speed lifting step is the same as the high-speed lifting step of the operation of the processing apparatus (1) in the above embodiment. In the first and second low-speed lifting steps, the rotation of the motor (140) is controlled by flow rate control. In the first and second low-speed lifting steps, the flow rate of the hydraulic fluid is kept constant. Specifically, in the first and second low-speed lifting steps, the target flow rate is determined based on the fourth output value. The target flow rate in the first low-speed lifting step is lower than the target flow rate in the high-speed lifting step. In the first and second low-speed lifting steps, the rotational speed of the motor (140) is controlled based on the target flow rate, and the rod (113) rises at a constant speed.

[0102] Conventionally, precisely controlling the load acting on the press material requires a separate load control device from the pump control device. Compared to a typical press working machine that only controls hydraulic pressure from a pump, the cost increases due to the addition of the load control device. Furthermore, when a load control device is installed, signals are transmitted via analog voltage between the main machine control unit (300) and the load control device, and between the load control device and the pump control unit. However, if the signal deteriorates due to voltage drops or noise caused by the wiring, the accuracy of the load control decreases. In addition, it is necessary to connect wiring from the load sensor to both the main machine control unit and the load control device, which increases the man-hours and costs required to install such wiring.

[0103] In this modified processing apparatus (1), a load control unit (216) is provided within the pump control unit (200). By incorporating software for calculating load control into the pump control unit (200) in this way, the need for a separate load control unit is eliminated, thus reducing costs. In addition, signal degradation can be suppressed because the aforementioned analog voltage signal transmission is no longer required. Furthermore, the wiring connections are simplified, which reduces the aforementioned man-hours and costs.

[0104] 《Other Embodiments》 The above embodiments and their variations may also be configured as follows.

[0105] The pump control device (200) of the embodiment may be provided with either a first position interlocking unit (215a) or a second position interlocking unit (215b).

[0106] In the above embodiment, a second position linkage unit (215b) may be implemented instead of the first position linkage unit (215a). The second position linkage unit (215b) calculates an internal target pressure based on the position information of the target position and current position of the rod (113) and the target pressure, so that the thrust of the rod (113) changes continuously in conjunction with the current position. This is used when the compression process is performed by thrust control rather than speed control. Furthermore, depending on the molded product (machine part) to be pressed, the first position linkage unit (215a) and the second position linkage unit (215b) may operate in conjunction.

[0107] As shown in Figure 7, the processing apparatus (1) according to the above embodiment may have a control unit (700) in which a pump control device (200) and a main unit control unit (300) are integrated. The processing apparatus (1) according to the above modified example may also be configured to have a control unit (700).

[0108] As shown in Figure 8, the processing apparatus (1) may have a pump system (600) in which a pump unit (500) including a hydraulic pump (130), a motor (140), and a pressure sensor (160), and a pump control device (200) are integrated. In this case, the pump unit (500) and the pump control device (200) can be retrofitted to or replaced with an existing processing apparatus (1). The processing apparatus (1) according to the above modified example may also be configured to have a pump system (600).

[0109] While embodiments and modifications have been described above, it will be understood that a variety of changes in form and details are possible without departing from the spirit and scope of the claims. Furthermore, these embodiments and modifications may be combined or substituted as appropriate, as long as they do not impair the functions of the subject matter of this disclosure. The terms “first,” “second,” etc., described above are used to distinguish the phrases to which these terms are attached and do not limit the number or order of such phrases.

[0110] As described above, this disclosure is useful for control devices and pump systems.

[0111] 100 Main engine 110 Hydraulic cylinder (actuator) 113 Rod 130 Hydraulic pump 140 Motor 160 Pressure sensor 190 Position sensor (first sensor) 191 Load sensor (first sensor) 200 Pump control device (control device) 210 Communication unit 211 Pressure control unit 212 Flow control unit 214 Position control unit (first control unit) 215 Position interlocking unit 216 Load control unit (first control unit) 300 Main engine control unit 500 Pump unit 600 Pump system 700 Control unit

Claims

1. A control device for controlling the hydraulic pump (130) of a main unit (100) comprising: a hydraulic pump (130) for transporting hydraulic fluid; a motor (140) for driving the hydraulic pump (130); an actuator (110) driven by the hydraulic fluid supplied from the hydraulic pump (130); a pressure sensor (160) for detecting the pressure of the hydraulic fluid transported to the actuator (110); and first sensors (190, 191) for detecting the physical quantities of the actuator (110), wherein the control device comprises: a flow control unit (212) for controlling the flow rate of the hydraulic fluid; a pressure control unit (211) for controlling the pressure of the hydraulic fluid; and first control units (214, 216) for controlling the physical quantities of the actuator (110), A control device comprising a communication unit (210) that receives first information including a target value of the physical quantity of the actuator (110) output from a main unit control unit (300) connected to the main unit (100) and the current value of the physical quantity output from the first sensors (190, 191), wherein the control device selects the necessary control for each process of the main unit (100) based on the first information.

2. The control device according to claim 1, wherein, based on the first information, the flow rate control unit (212), the pressure control unit (211), and the first control unit (214, 216) are selected from among the flow rate control unit (212), the pressure control unit (211), and the first control unit (214, 216) so that the necessary control is performed for each process of the main unit (100).

3. The control device according to claim 1 or 2, wherein the first sensor (190, 191) is a position sensor (190) that detects the position of the actuator (110), the first control unit (214, 216) is a position control unit (214) that controls the position of the actuator (110), and the current value indicates the current position of the actuator (110).

4. The control device according to claim 1 or 2, wherein the first sensor (190, 191) is a load sensor (191) that detects the force acting on an object by the actuator (110), the first control unit (214, 216) is a load control unit (216) that controls the force acting on an object by the actuator (110), and the current value indicates the current force acting on an object by the actuator (110).

5. The control device according to claim 3, wherein the actuator (110) is controlled to perform a plurality of consecutive steps, and further comprises a position interlocking unit (215) that controls the flow control unit (212) or the pressure control unit (211) so that when transitioning from a predetermined step to the next step, the actuator (110) in motion changes speed continuously and smoothly.

6. The control device according to claim 5, wherein the position interlocking unit (215) interpolates the step change of the target flow rate or target pressure of the hydraulic fluid in proportion to the amount of movement of the actuator (110) when transitioning from a predetermined step to the next step.

7. A control unit comprising the control device (200) and the main unit control unit (300) according to any one of claims 1 to 6.

8. A pump system comprising a pump unit (500) including the hydraulic pump (130), the motor (140), and the pressure sensor (160) according to any one of claims 1 to 6, and the control device (200).

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