Dual drive control system for machine tool and control method thereof

Abstract

According to the dual-drive control system of the machine tool of the present invention, it includes a numerical control unit; a main operating unit; a PLC, which executes control instructions by communicating with the numerical control unit or the main operating unit; a servo drive, which has a notch filter unit and executes the control instructions of the PLC; a servo motor unit, which is driven according to the control of the servo drive; and a power conversion unit, which is electrically connected to the servo motor unit and the servo drive and is used to apply current to the servo motor unit, wherein the servo drive adjusts the application state of the current transmitted to the power conversion unit according to the change of the notch filter coefficient calculated in real time by the notch filter unit, thereby performing resonance suppression caused by the operation of the servo motor unit.

Description

Technical Field

[0001] The present invention relates to a dual-drive control system for a machine tool and a control method thereof. More specifically, the present invention relates to a dual-drive control system for a machine tool that calculates a notch filter coefficient of a notch filter unit in real time through a notch filter control unit and adjusts the application state of a current applied to a power conversion unit in real time based on the calculated notch filter coefficient. Thus, the dual-drive control is used to suppress resonance generated when two servo motors are operated in parallel using a power conversion unit and a servo driver. This improves the stability and reliability of the machine tool, increases the cost-effectiveness of the operator, saves manufacturing costs and maintenance costs, and seeks to miniaturize the machine tool. Background Art

[0002] Generally speaking, a machine tool refers to a machine used to process metal / non-metal workpieces into the desired shape and size using various cutting or non-cutting methods using appropriate tools.

[0003] Various machine tools such as turning centers, vertical / horizontal machining centers, portal machining centers, switchgear, electrical discharge machines, horizontal NC drilling machines, and CNC lathes are widely used in various industrial sites according to the purpose of the corresponding work.

[0004] Generally, many machine tools currently in use have a control console that uses numerical control (NC) or CNC (computerized numerical control) technology. This console has various function switches or buttons and a monitor.

[0005] In addition, machine tools are equipped with: a transfer table for placing workpieces, i.e. materials, and transferring them for processing; a pallet for preparing the workpiece before processing; a spindle for rotating in conjunction with the tool or workpiece; a tailstock for supporting the workpiece during processing; and a vibration-proof device.

[0006] Generally, a machine tool includes a transfer table, a tool table, a main spindle, a tailstock, a vibration isolation device, and the like, and includes a transfer unit that moves along a transfer axis to perform various types of processing.

[0007] Furthermore, in general, a machine tool uses a plurality of tools to perform various types of machining, and also uses a tool magazine or a turret in the form of a tool storage area for accommodating and storing the plurality of tools.

[0008] Generally, in order to improve the productivity of a machine tool, the machine tool is equipped with an automatic tool changer (ATC) that extracts or replaces a specific tool from a tool magazine according to a command from a numerical control unit.

[0009] In addition, in order to minimize non-processing time, machine tools are generally equipped with an automatic pallet changer (APC). The automatic pallet changer (APC) automatically exchanges pallets between the workpiece processing area and the workpiece setting area. Workpieces can be loaded onto the pallet.

[0010] Typically, machine tools use servo motors to drive automatic tool changers (ATCs), automatic pallet changers (APCs), tailstocks, and anti-vibration devices.

[0011] As mentioned above, a device that controls an automatic tool changer (ATC) or an automatic pallet changer (APC), a tailstock, or an anti-vibration device by controlling a servo motor is called a servo control device.

[0012] In particular, in large automatic pallet changers (APCs) that are bulky or require great force, two servo motors are operated in parallel to drive one axis for productivity and economic reasons, as well as because a single servo motor cannot provide sufficient torque. This is called tandem control.

[0013] However, if Figure 1 As shown, when two servo motors are used, the existing servo control device combines an inverter and a servo driver with each servo motor. That is, the first servo motor 30 is connected to the first inverter 20 and the first servo driver 10, and the second servo motor 31 is connected to the second inverter 21 and the second servo driver 11 to operate in a multi-inverter multi-servo motor mode.

[0014] However, multi-inverter multi-servo motors require that each servo motor be combined with an inverter and a servo driver. This increases the size of the device, manufacturing and maintenance costs, and makes it impossible to achieve miniaturization of the machine tool.

[0015] In order to solve the above problem, Figure 2 As shown, a single inverter multiservo motor solution is proposed in which one inverter 20 and one servo driver 10 are operated in parallel with two servo motors 30 and 31 .

[0016] However, unlike induction motors that experience slip, servo motors, as permanent magnet synchronous motors, do not experience slip. Therefore, two servo motors can only operate stably in parallel if they are synchronized to eliminate speed deviation. Otherwise, resonance and step loss will reduce the stability and reliability of the servo control device, ultimately leading to reduced stability and reliability of the machine tool and reduced machining precision.

[0017] In order to solve the resonance suppression control problem, three dual-drive control systems and control methods thereof have been proposed in the past.

[0018] The first is an attenuation control device and method utilizing an auxiliary inverter and an auxiliary winding. The device and method additionally include a main inverter and an auxiliary inverter to form a structure of a servo motor and an auxiliary winding. However, due to the presence of two existing inverters, there are still problems such as increased manufacturing costs and difficulty in mass production.

[0019] The second type is an active damping control device and method, which only sets resonance suppression control through empirical methods. Therefore, it cannot flexibly handle actual resonance or many interferences or variables. It has the problem of always being unable to ensure the reliability and stability of the servo control device, and only increasing manufacturing costs.

[0020] The third type is a vibration reduction device and method utilizing a load oscillation analyzer. This device and method calculates resonance suppression control empirically, requiring a sensor capable of sensing the vibration phenomenon of the magnetic shaft current. This increases manufacturing costs, and resonance suppression control is executed without considering the actual resonance or real-time changes caused by the device's operating status. This significantly reduces accuracy and reliability, ultimately leading to reduced machining precision and reliability of the machine tool.

[0021] In addition, generally speaking, in order to suppress the resonance phenomenon, there are methods of avoiding the operating frequency band or attenuating the resonance using a notch filter through the above-mentioned three dual-drive control systems and their control methods.

[0022] like Figure 3 and Figure 4 As shown, when a notch filter is generally used to suppress resonance, it is necessary to determine the resonant frequency (ω O ), the coefficient of the attenuation amplitude (α) of the notch filter and the bandwidth (Q) of the notch filter.

[0023] However, generally speaking, even for servo motors of the same model from the same manufacturer, the coefficients of the notch filters differ depending on the manufacturing time and design differences. Furthermore, even for servo motors of the same capacity, the coefficients of the notch filters differ depending on the manufacturer.

[0024] Furthermore, since the resonant frequency, attenuation level, and bandwidth of the notch filter generated during machine tool operation change in real time, there is a problem in that the equipment tuning or equipment setup to suppress resonance through dual-drive control for each machine tool requires a lot of time and expense, causing inconvenience to the staff and reducing productivity.

[0025] Therefore, there is an urgent need to develop a dual-drive control system for a machine tool using a notch filter and a control method thereof, which is independent of the capacity or type of the servo motor, can accurately calculate the notch filter coefficient that changes in real time, output a resonance attenuation instruction based on the calculated notch filter coefficient, and cut off the current transmitted to the power conversion unit at the frequency that produces resonance through the output resonance attenuation instruction to perform resonance suppression. Summary of the Invention

[0026] Technical issues

[0027] The present invention is proposed to solve the above-mentioned problems. The purpose of the present invention is to provide a dual-drive control system for a machine tool and a control method thereof, wherein a notch filter coefficient of a notch filter unit is calculated in real time by a notch filter control unit, and the notch filter unit cuts off or applies the current transmitted to the power conversion unit according to the notch filter coefficient calculated in real time. Therefore, regardless of the type and capacity of the servo motor, the resonance suppression generated when two servo motors are operated in parallel using a power conversion unit and a servo driver is stably set and operated through the dual-drive control, thereby improving the convenience of the workers. Finally, by controlling a device driven by a servo motor such as an automatic tool changer or an automatic pallet changer, it is possible to save manufacturing costs, improve reliability due to noise reduction, and achieve miniaturization of the device.

[0028] In addition, another object of the present invention is to provide a dual-drive control system for a machine tool and a control method thereof, wherein the notch filter coefficient is calculated in real time in the notch filter control unit, and the resonance attenuation instruction is output from the instruction unit using the notch filter coefficient through the zero-pole elimination technology, and the notch filter unit applies or cuts off the current transmitted to the power conversion unit. Thus, by adjusting the current applied from the power conversion unit to the first servo motor and the second servo motor, and performing synchronized precise dual-drive control at all speeds and positions of the two servo motors, regardless of the type of servo motor unit, the servo control accuracy and reliability of the automatic tool exchange device or the automatic pallet exchange device can be greatly improved, and maintenance costs can be saved.

[0029] Technical Solution

[0030] In order to achieve the purpose of the present invention, the dual-drive control system of the machine tool according to the present invention includes: a numerical control unit; a main operating unit; a PLC, which executes control instructions by communicating with the numerical control unit or the main operating unit; a servo driver, which has a notch filter unit and executes the control instructions of the PLC; a servo motor unit, which is driven according to the control of the servo driver; and a power conversion unit, which is electrically connected to the servo motor unit and the servo driver and is used to apply current to the servo motor unit, and the servo driver adjusts the application state of the current transmitted to the power conversion unit according to the change of the notch filter coefficient calculated in real time by the notch filter unit, thereby performing resonance suppression caused by the operation of the servo motor unit.

[0031] Moreover, according to other preferred embodiments of the dual-drive control system of a machine tool of the present invention, the servo driver of the dual-drive control system of the machine tool includes: an output unit for outputting the operating speed signal of the servo motor unit and the torque signal transmitted to the power conversion unit; and a notch filter control unit for calculating the notch filter coefficient of the notch filter unit in real time, and controlling whether to apply the current transmitted to the power conversion unit based on the calculated notch filter coefficient.

[0032] Moreover, according to other preferred embodiments of the dual-drive control system of a machine tool of the present invention, the servo motor part of the dual-drive control system of the machine tool includes a first servo motor and a second servo motor connected in parallel with each other. According to the real-time change of the notch filter coefficient of the notch filter part, it is adjusted in real time whether to apply the current transmitted to the first servo motor and the second servo motor respectively through the power conversion part, thereby suppressing the resonance generated in the dual-drive control process of the first servo motor and the second servo motor.

[0033] Moreover, according to other preferred embodiments of the dual-drive control system of a machine tool according to the present invention, the notch filter control unit of the dual-drive control system of the machine tool may include: a memory unit for storing dual-drive control information for suppressing resonance generated when the first servo motor and the second servo motor operate in parallel; a calculation unit for calculating a notch filter coefficient of the notch filter unit using information stored in the memory unit; and an instruction unit for cutting off the current applied to the power conversion unit by the notch filter unit through a resonance attenuation instruction based on the result of the calculation unit, thereby performing resonance suppression in real time through dual-drive control.

[0034] Moreover, according to other preferred embodiments of the dual-drive control system of a machine tool according to the present invention, the memory unit of the dual-drive control system of the machine tool includes: a basic data storage unit for storing information related to the maximum value of the magnetic flux linkage of the corresponding permanent magnet, the angular velocity at the action point, the DC gain of the notch filter unit, the inductance of the stator winding of the servo motor unit, the pole constant of the servo motor unit, the stator winding resistance of the servo motor unit, and the rotor inertia moment of the servo motor unit; a feedback data storage unit for storing position and speed feedback information of the first servo motor generated when the first servo motor and the second servo motor are operated in parallel, and position and speed feedback information of the second servo motor generated when the second servo motor and the first servo motor are operated in parallel; and a real-time data storage unit for storing the real-time notch filter coefficient of the notch filter unit calculated by the operation unit and the current resonance attenuation instruction output by the instruction unit.

[0035] Moreover, according to other preferred embodiments of the dual-drive control system of a machine tool according to the present invention, the operation unit of the dual-drive control system of the machine tool may include: a damping coefficient calculation unit, which calculates the damping coefficient of the servo motor unit based on the data stored in the basic data storage unit; a natural frequency calculation unit, which calculates the natural frequency of the servo motor unit based on the data stored in the basic data storage unit; a pole calculation unit, which calculates the poles of the dual-drive control system based on the data stored in the basic data storage unit, the calculated value of the damping coefficient calculation unit, and the calculated value of the natural frequency calculation unit; a zero point calculation unit, which calculates the zero point of the notch filter unit based on the data stored in the basic data storage unit, the calculated value of the damping coefficient calculation unit, and the calculated value of the natural frequency calculation unit; and a coefficient calculation unit, which calculates the notch filter coefficient based on the data stored in the basic data storage unit, the calculated value of the damping coefficient calculation unit, the calculated value of the natural frequency calculation unit, the calculated value of the pole calculation unit, and the zero point value of the zero point calculation unit.

[0036] Moreover, according to other preferred embodiments of the dual-drive control system of a machine tool according to the present invention, the instruction unit of the dual-drive control system of the machine tool can utilize the data stored in the basic data storage unit, the calculated value of the damping coefficient calculation unit, the calculated value of the natural frequency calculation unit, the calculated value of the pole calculation unit, the zero point value of the zero point calculation unit, and the notch filter coefficient value of the calculation unit to output a resonance attenuation instruction through the zero-pole elimination technology.

[0037] Moreover, according to other preferred embodiments of the dual-drive control system of a machine tool according to the present invention, the output part of the dual-drive control system of a machine tool may include: a speed signal output part, which outputs the operating speed signal of the servo motor part according to the position instruction received from the numerical control part and the feedback signal received from the feedback data storage part; and a torque signal output part, which outputs the effective torque signal transmitted to the power conversion part to drive the servo motor part according to the speed signal received from the speed signal output part and the feedback signal received from the feedback data storage part.

[0038] In order to achieve other objects of the present invention, the control method of the dual-drive control system of the machine tool according to the present invention includes: the steps of storing basic data of the servo motor unit and the notch filter unit for dual-drive control; calculating the damping coefficient and natural frequency of the servo motor unit; calculating the poles of the dual-drive control system; calculating the zeros of the notch filter unit; calculating the notch filter coefficient of the notch filter unit by using the stored basic data, the calculated damping coefficient and natural frequency of the servo motor unit, the poles of the dual-drive control system and the zeros of the notch filter unit; executing the control instruction in the PLC by communicating with the numerical control unit or the main operation unit; executing the control instruction transmitted from the PLC to the servo driver; a step of providing a control instruction; a step of applying a current to a servo motor unit having a first servo motor and a second servo motor according to a signal of the servo driver by a power conversion unit; a step of storing position and speed feedback information of the first servo motor generated when the first servo motor and the second servo motor are operated in parallel, and position and speed feedback information of the second servo motor generated when the second servo motor and the first servo motor are operated in parallel; and a step of outputting a resonance attenuation instruction in real time according to the calculated notch filter coefficient, wherein the notch filter unit cuts off the current applied to the power conversion unit through the notch filter coefficient and the resonance attenuation instruction calculated in real time, thereby performing resonance suppression in real time through dual drive control.

[0039] According to other preferred embodiments of the resonance suppression control method of a machine tool of the present invention, the control method of the dual-drive control system of a machine tool may further include: after outputting the resonance attenuation instruction, storing the current notch filter coefficient calculated in real time and the resonance attenuation instruction output in real time.

[0040] Effects of the Invention

[0041] The dual-drive control system of the machine tool and the control method thereof according to the present invention have the following effects: the notch filter coefficient of the notch filter part is calculated in real time by the notch filter control part, and the current transmitted to the power conversion part is cut off or applied by the notch filter part according to the notch filter coefficient calculated in real time. Therefore, regardless of the type and capacity of the servo motor, the resonance generated when two servo motors are operated in parallel with one power conversion part and one servo driver can be stably set and operated through the dual-drive control, thereby improving the convenience of the staff. Finally, by controlling the device driven by the servo motor such as the automatic tool changing device or the automatic pallet changing device, the manufacturing cost can be saved and the reliability brought by the noise reduction can be improved. It can be universally used regardless of the type and capacity of the servo motor, thereby increasing the interchangeability of the dual-drive control system and the control method thereof.

[0042] In addition, the dual-drive control system of a machine tool and the control method thereof according to the present invention have the following effects: for the resonance generated when two servo motors are operated in parallel using a single power unit and a power conversion unit, resonance suppression is performed by applying or cutting off the current transmitted to the power conversion unit according to a resonance attenuation instruction using a notch filter coefficient calculated in real time by the notch filter unit. As a result, unnecessary components can be removed, miniaturization of the machine tool and the dual-drive control system of the machine tool can be achieved, and space utilization can be greatly improved.

[0043] Furthermore, the dual-drive control system of the machine tool according to the present invention and the control method thereof have the following effects: based on the feedback information of the first servo motor and the feedback information of the second servo motor received in real time from the feedback data storage unit, the notch filter coefficient received in real time from the data storage unit, and the current resonance attenuation instruction, the resonance generated when two servo motors are operated in parallel with one power unit and a power conversion unit is suppressed, and the dual-drive control is performed in real time by using the notch filter unit with zero-pole elimination technology to accurately control the resonance suppression of the two servo motors, thereby greatly improving the precision and reliability of the servo control device of the automatic tool exchange device or the automatic pallet exchange device, and increasing the stability and processing efficiency of the machine tool.

[0044] In addition, the dual-drive control system of the machine tool and its control method according to the present invention have the following effects: regardless of the type and capacity of the servo motor, the resonance generated when two servo motors are operated in parallel with one power unit and power conversion unit can be automatically suppressed in real time, thereby improving the convenience of the staff, minimizing non-processing time, and greatly improving the productivity of the machine tool. BRIEF DESCRIPTION OF THE DRAWINGS

[0045] Figure 1A conceptual diagram showing a conventional multi-inverter multi-servo motor in which one inverter and one servo driver are combined with one servo motor.

[0046] Figure 2 This diagram shows the concept of a single-inverter multi-servo motor system that combines one inverter and one servo driver with two servo motors to perform dual drive control.

[0047] Figure 3 and Figure 4 This is a graph for explaining the frequency characteristics of a conventional notch filter.

[0048] Figure 5 A block diagram showing the structure of a dual-drive control system for a machine tool according to an embodiment of the present invention.

[0049] Figure 6 A block diagram illustrating the configuration of a notch filter control unit of a servo driver in a dual-drive control system for a machine tool according to an embodiment of the present invention.

[0050] Figure 7 This is a graph for explaining a process in which a resonance damping command is outputted by a zero-pole cancellation technique in a command unit of a dual-drive control system of a machine tool according to the present invention.

[0051] Figure 8 1 is a sequence diagram of a control method of a dual-drive control system of a machine tool according to an embodiment of the present invention.

[0052] Figures 9 and 10 This is a graph for explaining the resonance suppression control effect achieved by the dual-drive control system of a machine tool and the control method thereof according to an embodiment of the present invention. DETAILED DESCRIPTION

[0053] Below, a detailed description of a dual-drive control system for a machine tool and a method thereof according to an embodiment of the present invention is provided with reference to the figures. The embodiments described below are provided as examples to fully convey the concepts of the present invention to those skilled in the art. Therefore, the present invention is not limited to the embodiments described below and may be embodied in other forms. Furthermore, in the figures, the size and thickness of the device may be exaggerated for convenience. Throughout this specification, the same symbols represent the same components.

[0054] The advantages, features, and techniques for achieving these advantages of the present invention will become apparent through the accompanying drawings and the following embodiments. However, the present invention is not limited to the following embodiments and can be embodied in various other forms. This embodiment further completes the disclosure of the present invention and provides a complete scope of the invention to those skilled in the art. Throughout this specification, the same symbols represent the same components. For clarity, the sizes and relative sizes of layers and regions in the figures may be exaggerated.

[0055] The terms used in this specification are intended to illustrate the embodiments and do not limit the present invention. Unless otherwise specified in this specification, the singular also includes the plural. The terms "comprise" and / or "comprising" used in this specification mean that the referenced constituent elements, steps, actions, and / or components do not exclude the presence or addition of one or more other constituent elements, steps, actions, and components.

[0056] Figure 5 A block diagram showing the structure of a dual-drive control system for a machine tool according to an embodiment of the present invention is provided. Figure 6 A block diagram illustrating the configuration of a notch filter control unit of a servo driver in a dual-drive control system for a machine tool according to an embodiment of the present invention. Figure 7 This is a graph for explaining a process in which a resonance damping command is outputted by a zero-pole cancellation technique in a command unit of a dual-drive control system of a machine tool according to the present invention. Figure 8 1 is a sequence diagram of a control method of a dual-drive control system of a machine tool according to an embodiment of the present invention. Figures 9 and 10 This is a graph for explaining the resonance suppression control effect achieved by the dual-drive control system of a machine tool and the control method thereof according to an embodiment of the present invention.

[0057] refer to Figures 5 to 7 The dual drive control system 1 of a machine tool according to an embodiment of the present invention is described. Figure 5 and Figure 6 As shown, a dual-drive control system 1 for a machine tool according to an embodiment of the present invention includes: a numerical control unit 100 , a main operation unit 200 , a PLC 300 , a servo driver 400 , a servo motor unit 600 , and a power conversion unit 500 .

[0058] The numerical control unit 100, which includes either NC (numerical control) or CNC (computerized numerical control), internally stores various numerical control programs. Specifically, the NC unit 100 stores servo motor drivers and tool operation programs. These programs are automatically loaded and activated when the NC unit is activated. Furthermore, the NC unit 100 communicates with the main operating unit 200, PLC 300, and servo driver 400 using a predetermined protocol.

[0059] In addition, the numerical control unit 100 receives feedback information from the first servo motor 610 or the second servo motor 620 of the servo motor unit 600 for driving the automatic tool changer (ATC) or the automatic pallet changer (APC). More specifically, the numerical control unit 100 receives feedback information regarding the position and speed of the first servo motor 610 or the second servo motor 620 from the feedback data storage unit 4312 of the memory unit 431 of the notch filter control unit 430, which will be described later.

[0060] The main operating unit 200 includes a screen display program and a data input program based on the screen display selection. By outputting the screen display program, a software switch is displayed on the display screen, and the on / off state of the software switch is identified, thereby executing the function of issuing input and output instructions for machine tool operations.

[0061] In addition, the main operating unit 200 includes a display, which is provided on the housing, casing or one side of the machine tool and can display a variety of function switches or buttons and various information, but is not limited thereto.

[0062] The PLC (Programmable Logic Controller) 300 communicates with the numerical control unit 100 or the main operating unit 200 via a predetermined protocol. This communication enables the PLC 300 to execute control instructions. Specifically, the PLC 300 receives control instructions from the numerical control program in the numerical control unit 100 or the main operating unit 200 and executes them.

[0063] After receiving and executing control commands from the numerical control unit 100 or the main operation unit 200, the PCL 300 outputs the commands to the numerical control unit 100, which then transmits the control commands to the servo driver 400 via the main operation unit 200. If necessary, the PLC 300 can also transmit control commands from the user to the servo driver 400 in real time via the main operation unit 200.

[0064] The servo driver 400 executes control commands from the PLC 300. Specifically, the servo driver 400 controls the drive of the servo motor of the servo motor unit 500 (described later) based on the control commands from the PLC 300. Ultimately, it controls the drive of various servo motor-driven machine tool components, such as the automatic tool changer (ATC) or automatic pallet changer (APC), the tailstock, and the anti-vibration device. The servo driver 400 transmits control results to the PLC 300 via contacts or communication based on a predetermined protocol.

[0065] In addition, the servo driver 400 receives feedback information from the first servo motor 610 or the second servo motor 620 of the servo motor unit 600 for driving an automatic tool changer (ATC) or an automatic pallet changer (APC). More specifically, the numerical control unit 100 receives feedback information regarding the position and speed of the first servo motor 610 or the second servo motor 620 from the feedback data storage unit 4312 of the memory unit 431 of the first notch filter control unit 430, which will be described later.

[0066] The servo motor unit 600 is driven by the control of the servo driver 400 .

[0067] like Figure 5 As shown, the servo motor unit 600 of the servo control device 1 for a machine tool according to an embodiment of the present invention includes a first servo motor 610 and a second servo motor 620 .

[0068] The first servo motor 610 and the second servo motor 620 are connected in parallel to a power conversion unit 500 to be described later, and are operated in parallel by current applied to the power conversion unit 500 according to a control signal of a servo driver.

[0069] In addition, according to the real-time change of the notch filter coefficient of the notch filter part, whether to apply the current transmitted to the first servo motor and the second servo motor respectively through the power conversion part is adjusted in real time, thereby performing resonance suppression generated in the dual drive control of the first servo motor and the second servo motor.

[0070] In addition, the servo motor unit 600 is driven by the first servo motor 610 or the second servo motor 620 according to the control of the servo driver 400 in accordance with the corresponding sequence information and position information or program.

[0071] The power conversion unit 500 is electrically connected to the servo motor unit 600 and the servo driver 400 . In addition, the power conversion unit 500 applies electric energy to the servo motor unit 600 in response to a contact signal from the servo driver 400 .

[0072] As described above, according to the dual-drive control system of a machine tool of the present invention, the notch filter control unit 433 calculates the notch filter coefficients of the notch filter unit in real time, and the notch filter unit 420 cuts off or applies the current transmitted to the power conversion unit 500 based on the notch filter coefficients calculated in real time. This suppresses the resonance that occurs when each of the first servo motor 610 and the second servo motor 620 of the servo motor unit 600 operates in parallel. Specifically, the notch filter unit 420, upon receiving the resonance damping command and the resonance damping command signal output from the command unit 430 of the servo driver, cuts off the current supplied to the power conversion unit 500 at a specific frequency and supplies the current supplied to the power conversion unit 500 at other frequencies. This adjusts the current applied or cut off to each of the first servo motor 610 and the second servo motor 620 in real time, and suppresses the resonance that occurs when the first servo motor 610 and the second servo motor 620 operate in parallel through dual-drive control using the notch filter unit.

[0073] Therefore, the notch filter coefficient of the notch filter unit is calculated in real time by the notch filter control unit, and the current transmitted to the power conversion unit is cut off or applied by the notch filter unit according to the notch filter coefficient calculated in real time. Therefore, regardless of the type or capacity of the servo motor, the resonance generated when two servo motors are operated in parallel using one power conversion unit and one servo driver can be stably set and operated through dual-drive control, thereby improving the convenience of the staff. Finally, by controlling devices driven by servo motors such as automatic tool changers or automatic pallet changers, manufacturing costs can be saved and reliability brought about by noise reduction can be improved. Moreover, it can be universally used regardless of the type and capacity of the servo motor, thereby increasing the interchangeability of the dual-drive drive system and its control method.

[0074] like Figure 5 As shown, the servo driver 400 of the dual-drive control system 1 for a machine tool according to an embodiment of the present invention includes an output unit 410 , a notch filter unit 420 and a notch filter control unit 430 .

[0075] Although not shown, the servo driver 400 of the machine tool's dual-drive control system may also include a controller, as needed. The controller is internal to the servo driver 400 and stores a detailed control instruction interpretation program, various machining programs, and driver programs. Furthermore, the controller communicates with the numerical control unit 100, main operating unit 200, PLC 300, servo motor unit 600, and power conversion unit 500 via a predetermined protocol.

[0076] As needed, the main operating unit 200 may transmit the control instructions of the main operating unit to the servo driver 400 directly through the PLC 300 without passing through the numerical control unit 100 .

[0077] As described above, since the detailed control instruction interpretation program or other control program is all stored inside the controller of the servo driver 400 described later, it is not necessary to receive the drive instructions of the servo motor unit 500 from the CNC unit 100. Instead, the servo driver 400 can execute the instructions through the main operating unit 200 and the PLC300 to drive the servo motor unit 600 described later.

[0078] Therefore, the detailed control instructions performed in the numerical control unit 100 can be executed by the controller of the servo driver 400, so that the servo driver function can be executed by programming the protocol function with other numerical control units only. In this way, multiple programs can be driven by the servo driver, which can greatly improve the interchangeability of the device and seek user convenience.

[0079] The output unit 410 outputs an operating speed signal of the servo motor unit 600 and a torque signal to be transmitted to the power conversion unit 500 .

[0080] In addition, if Figure 5 As shown, the output unit 410 of the dual-drive control system 1 of the machine tool according to the preferred embodiment of the present invention includes: a speed signal output unit 411 and a torque signal output unit 412.

[0081] The speed signal output unit 411 outputs an operating speed signal of the servo motor unit 600 according to the position command received from the numerical control unit 100 and the feedback signals of the first servo motor 610 and the second servo motor 620 received from the feedback information storage unit 4312 .

[0082] Specifically, during the initial driving of the dual-drive control system, the speed signal output unit 411 outputs an operating speed signal of the servo motor unit 600 based on the position command initially received from the numerical control unit 100, in a state before the first servo motor 610 and the second servo motor 620 are operating in parallel. Then, based on the speed command output by the speed signal output unit 411, feedback information of the first servo motor 610 generated when the first servo motor 610 and the second servo motor 620 of the servo motor unit 600 are operating in parallel is transmitted to the feedback data storage unit 4312. After the initial driving, the operating speed signal of the servo motor unit 600 is output based on the feedback signals of the first servo motor 610 and the second servo motor 620 transmitted through the feedback information storage unit 440 and the position command received from the numerical control unit 100.

[0083] The torque signal output unit 412 outputs an effective torque signal to be transmitted to the power conversion unit 500 to drive the servo motor unit 600 based on the speed signal received from the speed signal output unit 411 and the feedback signal received from the feedback data storage unit 4312 .

[0084] Specifically, during the initial driving of the dual-drive control system, the torque signal output unit 412 outputs an effective torque signal to the power conversion unit 500 based on the speed command initially received by the speed signal output unit 411, in a state before the first servo motor 610 and the second servo motor 620 are operated in parallel, thereby driving the servo motor unit 600. Then, based on the effective torque signal output by the torque signal output unit 412, feedback information from the first servo motor 610 and the second servo motor 620 generated when the power conversion unit 500 drives the first servo motor 610 and the second servo motor 620 of the servo motor unit 600 to operate in parallel is transmitted to the feedback data storage unit 4312. After the initial driving, the effective torque signal transmitted through the feedback data storage unit 4312 and the operating speed signal received from the speed signal output unit 411 are output to the power conversion unit 500.

[0085] The notch filter unit 420 blocks the current applied to the power conversion unit 500 at a specific frequency, and directly passes the current applied to the power conversion unit 500 at other frequencies without filtering.

[0086] The notch filter control unit 430 calculates the notch filter coefficient of the notch filter unit in real time and controls whether to apply the current transmitted to the power conversion unit based on the calculated notch filter coefficient. Specifically, the notch filter control unit 430 calculates the damping coefficient and natural frequency of the servo motor before the initial drive of the dual-drive control system, and calculates the notch filter coefficient of the notch filter unit. In addition, after the initial drive of the dual-drive control system, after the first servo motor 610 and the second servo motor 620 of the servo motor unit 600 operate in parallel, the notch filter control unit 430 outputs a resonance attenuation command to cut off the transmission to the power conversion unit 500 through the notch filter unit, thereby performing the function of suppressing the resonance generated when the first servo motor 610 and the second servo motor 620 operate in parallel.

[0087] The output unit 410 , the notch filter unit 420 and the notch filter control unit 430 are all installed inside the servo driver 400 , and a detailed control instruction interpretation program, or various processing programs and driver programs may be stored inside.

[0088] In addition, the output unit 410 , the notch filter unit 420 , and the notch filter control unit 430 may communicate with the numerical control unit 100 , the main operation unit 200 , the PLC 300 , the servo motor unit 600 , and the power conversion unit 500 through a predetermined protocol.

[0089] Therefore, in the dual-drive control system of the machine tool according to the present invention, the resonance generated when two servo motors are operated in parallel with one power unit and power conversion unit is suppressed by applying or cutting off the current transmitted to the power conversion unit by the notch filter unit according to the resonance attenuation instruction using the notch filter coefficient calculated in real time. As a result, unnecessary components can be removed, the machine tool and the dual-drive control system of the machine tool can be miniaturized, and space utilization can be greatly improved.

[0090] like Figure 5 and Figure 6 As shown, the notch filter control unit 430 of the servo driver 400 of the dual-drive control system 1 for a machine tool according to an embodiment of the present invention includes a memory unit 431 , a calculation unit 432 and an instruction unit 433 .

[0091] The memory unit 431 stores various information for dual drive control for suppressing resonance generated when the first servo motor and the second servo motor operate in parallel.

[0092] The calculation unit 432 calculates the notch filter coefficients of the notch filter unit 420 in real time using the information stored in the memory unit 431 .

[0093] The command unit 433 uses a resonance damping command to cause the notch filter unit to cut off or pass the current applied to the power conversion unit based on the result of the calculation unit 431 , thereby suppressing resonance in real time through dual drive control.

[0094] The memory unit 431 , the calculation unit 432 , and the instruction unit 433 are provided inside the notch filter control unit 430 , and can store a detailed control instruction interpretation program, various processing programs, and a driver program.

[0095] In addition, the memory unit 431 , the calculation unit 432 and the instruction unit 433 can communicate with the numerical control unit 100 , the main operation unit 200 , the PLC 300 , the servo motor unit 600 , the power conversion unit 500 , the output unit 410 and the notch filter unit 420 through a predetermined protocol.

[0096] like Figure 5 As shown, the memory unit 431 of the notch filter control unit 430 of the servo driver 400 of the dual-drive control system 1 of the machine tool according to one embodiment of the present invention includes: a basic data storage unit 4311, a feedback data storage unit 4312 and a real-time data storage unit 4313.

[0097] The basic data storage unit 4311 is used to store information related to the maximum value of the magnetic flux linkage of the corresponding permanent magnet, the angular velocity at the operating point, the DC gain of the notch filter unit, the inductance of the stator winding of the servo motor unit, the pole constant of the servo motor unit, the stator winding resistance of the servo motor unit, and the rotor inertia moment of the servo motor unit.

[0098] The basic data can be stored by a worker through the numerical control unit 100 or the main operation unit 200, or can be stored in the PLC 300 in the form of a program.

[0099] The feedback data storage unit 4312 is used to store position and speed feedback information of the first servo motor 610 and the second servo motor 620 generated when the first servo motor 610 and the second servo motor 620 are operated in parallel, and position and speed feedback information of the second servo motor generated when the second servo motor is operated in parallel with the first servo motor.

[0100] As described above, the feedback data storage unit 4312 can be electrically connected to the output unit 410, the notch filter unit 420, the power conversion unit 500, the real-time data storage unit 4313, the servo motor unit 600, the CNC unit 100, the main operation unit 200 and the PLC300, and communicate through a predetermined protocol.

[0101] The real-time data storage unit 4313 is used to store the real-time notch filter coefficients of the notch filter unit calculated by the calculation unit and the current resonance attenuation instruction output by the instruction unit.

[0102] As described above, the real-time data storage unit 4313 can be electrically connected to the output unit 410, the notch filter unit 420, the power conversion unit 500, the feedback data storage unit 4312, the servo motor unit 600, the CNC unit 100, the main operation unit 200 and the PLC300, and communicate through a predetermined protocol.

[0103] like Figure 5 As shown, the operation unit 432 of the notch filter control unit 430 of the servo driver 400 of the dual-drive control system 1 of the machine tool according to one embodiment of the present invention includes: a damping coefficient calculation unit 4321, a natural frequency calculation unit 4322, a pole calculation unit 4323, a zero point calculation unit 4324 and a coefficient calculation unit 4325.

[0104] The damping coefficient calculation unit 4321 calculates the damping coefficient of the servo motor unit based on the data stored in the basic data storage unit.

[0105] The natural frequency calculation unit 4322 calculates the natural frequency of the servo motor unit based on the data stored in the basic data storage unit.

[0106] The pole calculation unit 4323 calculates the poles of the dual drive control system based on the data stored in the basic data storage unit, the damping coefficient calculation value of the damping coefficient calculation unit, and the natural frequency calculation value of the natural frequency calculation unit.

[0107] The zero point calculation unit 4324 calculates the zero point of the notch filter unit based on the data stored in the basic data storage unit, the damping coefficient calculation value of the damping coefficient calculation unit, and the natural frequency calculation value of the natural frequency calculation.

[0108] The coefficient calculation unit 4325 calculates the notch filter coefficient based on the data stored in the basic data storage unit, the damping coefficient calculation value of the damping coefficient calculation unit, the natural frequency calculation value of the natural frequency calculation unit, the pole calculation value of the dual drive control system of the pole calculation unit, and the zero point calculation value of the notch filter unit of the zero point calculation unit.

[0109] The instruction unit 433 outputs a resonance attenuation instruction using the zero-pole elimination technology based on the data stored in the basic data storage unit, the damping coefficient calculation value of the damping coefficient calculation unit, the natural frequency calculation value of the natural frequency calculation unit, the pole calculation value of the dual-drive control system of the pole calculation unit, the zero point calculation value of the notch filter unit of the zero point calculation unit, and the notch filter coefficient value of the coefficient calculation value.

[0110] Therefore, according to the dual-drive control system of the machine tool of the present invention, based on the feedback information of the first servo motor and the feedback information of the second servo motor received in real time from the feedback data storage unit, the notch filter coefficient received in real time from the data storage unit, and the current resonance attenuation instruction, the resonance generated when the two servo motors are operated in parallel through a power unit and a power conversion unit is suppressed, and the precise resonance suppression control of the two servo motors is performed in real time by performing dual-drive control through the notch filter unit using zero-pole elimination technology. As a result, the precision and reliability of the servo control device of the automatic tool exchange device or the automatic pallet exchange device can be greatly improved, and the stability and processing efficiency of the machine tool can be increased.

[0111] In addition, the dual-drive control system of the machine tool according to the present invention is independent of the type and capacity of the servo motors, and automatically suppresses and controls the resonance generated when the two servo motors operate in parallel through a power unit and a power conversion unit in real time, thereby seeking the convenience of the staff, minimizing non-processing time, and greatly improving the productivity of the machine tool.

[0112] refer to Figures 5 to 7 The calculation principle of the calculation unit 432 and the command unit 433 of the notch filter control unit 430 will be described. Specifically, the calculation unit 432 and the command unit 433 of the notch filter control unit 430 calculate the notch filter coefficient in real time according to the following principle and output the resonance attenuation command based on the calculated notch filter coefficient.

[0113] Under normal conditions, the state variable is expressed as X=X0+△X, and the linearized state equation is obtained using Taylor series, which is calculated using Mathematical Formula 1.

[0114] <Mathematical formula 1>

[0115]

[0116]

[0117]

[0118]

[0119]

[0120] However, in Mathematical Formula 1, the dual-drive control system operating in parallel is very complicated in order to evaluate the stability.

[0121] Therefore, to simplify Mathematical Formula 1, it is assumed that the mechanical time constant of the servo motor is sufficiently larger than the electrical time constant, and Mathematical Formula 1 is rearranged to obtain the value calculated using Mathematical Formula 2.

[0122] <Mathematical formula 2>

[0123]

[0124] Therefore, the transfer function obtained from equation 2 becomes equations 3 and 4.

[0125] <Mathematical formula 3>

[0126]

[0127] That is, the extreme point calculation unit 4323 calculates according to Mathematical Formula 3.

[0128] In addition, in Mathematical Formula 3, which is the characteristic equation of the transfer function, the damping coefficient and natural frequency of the servo motor part of the parallel operation dual drive control system are calculated by Mathematical Formula 5.

[0129] <Mathematical formula 4>

[0130]

[0131] That is, the zero point calculation unit 4324 calculates it using the mathematical formula 4.

[0132] <Mathematical formula 5>

[0133]

[0134]

[0135] That is, the damping coefficient calculation unit 4321 and the natural frequency calculation unit 4322 are calculated using Math. 4.

[0136] Figure 7 The conceptual diagram of the zero-pole elimination technique in the complex plane is shown in FIG. Figure 7 As shown, in general, when controlling, the denominator of the transfer function can be set to 0 to explain the response characteristics of the system. Therefore, the poles of the dual-drive control system of mathematical formula 3 are expressed on the complex plane ( Figure 7 (indicated by a dotted line X).

[0137] like Figure 7 As shown in FIG. 3 , the pole of the dual drive control system represented by Mathematical Formula 3 is close to the imaginary axis, which means that the dual drive control system operating as the power conversion unit resonates. Figure 7 As the X-axis is taken as the reference, it becomes more stable as it moves to the left, and shows an unstable state due to resonance as it moves to the right.

[0138] The numerator of equation 4, i.e., the zero of the notch filter, is arranged at the position of the denominator of equation 3, i.e., the pole of the dual-drive control system ( Figure 7 Indicated by the solid line O in the figure), if the poles of the notch filter are arranged in such a way as to eliminate the basic resonance component of the dual drive control system operated by one power conversion unit with the required performance ( Figure 7 (indicated by the solid line X in the figure), stable dual-drive control with suppressed resonance can be achieved, which is expressed by Mathematical Formula 6.

[0139] <Mathematical formula 6>

[0140]

[0141] That is, the resonance damping command of the command unit is derived from Mathematical Formula 6.

[0142] Then, the resonant frequency in the notch filter coefficient and the resonant frequency of the servo motor of the dual drive control system can be set as shown in Math Formula 7.

[0143] <Mathematical formula 7>

[0144] ω0=ω n

[0145] As a result, as described above, the notch filter coefficients represented by Equation 8 can be obtained by using the pole placement method by combining the zeros of the notch filter (the numerator of Equation 4) and the poles of the dual-drive control system (the denominator of Equation 3).

[0146] <Mathematical formula 8>

[0147]

[0148]

[0149] That is, the coefficient calculation unit 4325 is derived from mathematical formula 8.

[0150] Each factor in the above-mentioned Mathematical Formulas 1 to 8 is as follows.

[0151] αl: high frequency gain limit value

[0152] δ:V t and E f The torque angle between

[0153] ′δ: Torque angle in transition state

[0154] Δδ: Linearized torque angle

[0155] Δu: Input variable variation component

[0156] Δx: state variable change component

[0157] Δω r re : Linearized rotor angular velocity

[0158] ζ: decay constant

[0159] ω0: angular velocity at the action point

[0160] ω r re : angular velocity of the rotor

[0161] ω ω re : arbitrary angular velocity

[0162] ω s : Synchronous angular velocity

[0163] i uvw : Three-phase current

[0164] i r ds ,i r qs : Rotation coordinate system d r -q r Shaft stator current

[0165] i ω ds ,i ω qs : any coordinate system d ω -q ω Shaft stator current

[0166] ir* ds ,i r* qs : Rotation axis coordinate system d r -q r Axis stator command current

[0167] i ω* ds ,i ω* qs : any coordinate system d ω -q ω Axis stator command current

[0168] Kn: DC gain of notch filter

[0169] ω o : Notch filter resonant frequency

[0170] α: attenuation size of the notch filter

[0171] Q: Notch filter bandwidth

[0172] L s : Inductance of the motor stator winding

[0173] P f : Motor pole constant

[0174] R s : Resistance of the motor stator winding

[0175] V t : Terminal voltage

[0176] V uvw : Three-phase voltage

[0177] x: state variable

[0178] x0: state variable at the action point

[0179] J: Motor rotor inertia moment

[0180] S: σ+Jω (σ is a real number, Jω is an imaginary number, that is, S is a factor that shows the size and phase in the frequency space)

[0181] As described above, according to the dual-drive control system of a machine tool of the present invention, the notch filter coefficient of the notch filter unit is calculated in real time by the notch filter control unit, and the current transmitted to the power conversion unit is cut off or applied by the notch filter unit using the notch filter coefficient calculated in real time. Therefore, regardless of the type or capacity of the servo motor, the resonance suppression generated when two servo motors are operated in parallel using a single power conversion unit and a single servo driver is stably set and operated by the dual-drive control. This improves the convenience of the operator. Finally, by controlling a device driven by a servo motor, such as an automatic tool changer or an automatic pallet changer, manufacturing costs can be saved and reliability due to noise reduction can be improved. Moreover, the control system can be universally used regardless of the type and capacity of the servo motor. By automatically suppressing the resonance generated when two servo motors are operated in parallel using a single power unit and a power conversion unit in real time, the convenience of the operator can be achieved, non-machining time can be minimized, and the productivity of the machine tool can be greatly improved.

[0182] Although not shown in the drawings, the dual-drive control system 1 for a machine tool according to an embodiment of the present invention may further include an input unit and a display unit.

[0183] The input unit is provided in the form of a switch or a touch button on an operating panel or a main operating unit, so as to execute a function that can be arbitrarily selected by the staff to perform resonance suppression control or not in real time when the servo motor units are running in parallel.

[0184] That is, when the two servo motors of the servo motor unit of the dual drive control system of the machine tool are operated in parallel, if the input unit does not select the function of the notch filter control unit, the dual drive control system of the machine tool does not operate the resonance suppression control function.

[0185] The display shows the damping coefficient value, natural frequency value, pole calculation value, zero calculation value, notch filter coefficient value, and resonance attenuation command value of the calculation unit. These values allow real-time visual confirmation of whether resonance is suppressed and the control status when two servo motors in the servo motor unit are running in parallel.

[0186] The display unit can be composed of an LCD, LED, PDP display, etc. in the main operation unit or the numerical control unit, but is not necessarily limited to this.

[0187] like Figure 8As shown, the control method of the dual-drive control system of a machine tool according to a preferred embodiment of the present invention includes: a step of storing basic data (S1); a step of calculating the damping coefficient and natural frequency of the servo motor unit (S2); a step of calculating the poles of the dual-drive control system (S3); a step of calculating the zero points of the notch filter unit (S4); a step of calculating the notch filter coefficient (S5); a step of executing the PLC (S6); a step of executing the servo driver (S7); a step of applying power to the power conversion unit (S8); a step of storing feedback information (S9); a step of outputting a resonance attenuation instruction (S10); and a step of storing real-time data (S11). In each step, the specific execution or content of the system or device is the same as that of the dual-drive control system of the machine tool in the specification of the present invention. The following focuses on the special features of the control method of the dual-drive control system of the machine tool.

[0188] Basic data storage unit 4311 stores basic data related to the servo motor unit and notch filter unit for dual drive control. This information, including the maximum value of the magnetic flux linkage of the corresponding permanent magnets, the angular velocity at the operating point, the DC gain of the notch filter unit, the inductance of the servo motor unit's stator winding, the servo motor unit's pole constant, the servo motor unit's stator winding resistance, and the servo motor unit's rotor inertia moment, can be executed by the operator through CNC unit 100 or main operation unit 200 and stored in the PLC 300 in the form of a program.

[0189] After the basic data storage step ( S1 ), the damping coefficient and natural frequency of the servo motor unit are calculated. Specifically, the damping coefficient and natural frequency of the servo motor unit are calculated using Equation 5 by the damping coefficient calculation unit and the natural frequency calculation unit.

[0190] After the step ( S2 ) of calculating the damping coefficient and the natural frequency of the servo motor unit, the poles of the dual drive control system are calculated using Equation 3 in the pole calculation unit of the dual drive control system.

[0191] After the pole calculation step ( S3 ) of the dual drive control system, the zero point calculation unit of the notch filter unit calculates the zero point of the notch filter unit using Equation 4.

[0192] After the step (S4) of calculating the zero point of the notch filter unit, the coefficient calculation unit calculates the notch filter coefficient of the notch filter unit using Mathematical Formula 8 using the basic data stored in the basic data storage unit, the calculated damping coefficient and natural frequency of the servo motor unit, the poles of the dual-drive control system, and the zero point of the notch filter unit.

[0193] After the notch filter coefficient calculation step (S5), the control command is executed in the PLC through communication with the numerical control unit or the main operation unit.

[0194] After the PLC executes step (S6), the servo driver executes the control instruction sent from the PLC.

[0195] After the servo driver executes step ( S7 ), the power conversion unit applies current to the servo motor unit including the first servo motor and the second servo motor according to the signal from the servo driver.

[0196] After the power application step (S8) of the power conversion unit, position and speed feedback information of the first servo motor generated when the first servo motor and the second servo motor are operated in parallel, and position and speed feedback information of the second servo motor generated when the second servo motor and the first servo motor are operated in parallel are stored in the feedback data storage unit.

[0197] After the feedback information storage step (S9), the command unit outputs a resonance attenuation command in real time using Equation 6 based on the notch filter coefficient calculated by the coefficient calculation unit, and transmits it to the notch filter unit.

[0198] After the resonance damping command output step (S10), the current applied to the power conversion unit is cut off by the notch filter unit according to the notch filter coefficient and the resonance damping command calculated in real time, thereby suppressing resonance in real time through dual drive control.

[0199] Furthermore, after the resonance damping instruction output step ( S10 ), the current notch filter coefficient calculated in real time and the resonance damping instruction output in real time are stored.

[0200] Therefore, according to the control method of a dual-drive control system for a machine tool of the present invention, a notch filter control unit calculates a notch filter coefficient of the notch filter unit in real time, and uses the notch filter unit to cut off or apply current to the power conversion unit based on the notch filter coefficient calculated in real time. Thus, regardless of the type or capacity of the servo motors, dual-drive control stably sets and operates to suppress resonance generated when two servo motors are operated in parallel using a single power conversion unit and a single servo driver. This improves operator convenience. Ultimately, the control method can be used to control servo-motor-driven devices such as automatic tool changers and automatic pallet changers, thereby reducing manufacturing costs and improving reliability due to noise reduction. Furthermore, the method is universally applicable regardless of the type and capacity of the servo motors, thereby increasing the compatibility of the dual-drive control system and its control method. By applying or cutting off current to the power conversion unit based on a resonance damping command using the notch filter unit calculated in real time, resonance suppression can be performed. Consequently, unnecessary components can be eliminated, miniaturizing the machine tool and the dual-drive control system for the machine tool, and significantly improving space utilization.

[0201] refer to Figure 6 and Figure 7 The effects of the resonance suppression control device and the resonance suppression control method for a machine tool according to the present invention will be described in more detail. Figure 6 is a Bode diagram showing the change in vibration amount based on frequency, Figure 7 is a Bode diagram showing the phase difference based on frequency. Figure 6 as well as Figure 7 In FIG. 1 , the solid line represents a state where two servo motors are operated in parallel in a conventional servo control device, and the dotted line represents a state where the resonance suppression control device and the resonance suppression control method for a machine tool according to the present invention are applied.

[0202] like Figure 9 as well as Figure 10 As is known, in conventional machine tools that have not employed the dual-drive control system and method according to the present invention, resonance has occurred, and the phase has also been shown to be approximately 9 degrees relative to 180 degrees. In contrast, when the dual-drive control system and method according to the present invention are employed, resonance is eliminated without an inflection point, thereby completely suppressing resonance. The phase has also been shown to be 57 degrees relative to 180 degrees.

[0203] Specifically, if we observe the transfer function G(S) of the mathematical model of dual drive control ( Figure 9 and 10 The frequency response of the dot-dash line in the middle shows an unstable response with a resonance at 22.9 rad / sec and a phase margin of 9 degrees. However, the transfer function H(S) ( Figure 9 and 10 The notch filter (dashed line in the figure) attenuates the resonance point, which has increased to 19 dB, and the phase margin is 57 degrees. This confirms that the frequency response of the transfer function G0(S) of the entire dual-drive control system shows a stable response with suppressed resonance.

[0204] Finally, compared with the prior art, the dual-drive control system of the machine tool according to the present invention and the control method thereof can ensure more than 5 times the stability and reliability.

[0205] That is, according to the dual-drive control system of the machine tool and the control method thereof of the present invention, the calculation unit calculates the notch filter coefficient of the notch filter unit in real time through mathematical formulas 6 and 8, and the instruction unit reflects the coefficient to output a resonance attenuation instruction to cut off or apply the current applied to the power conversion unit, and controls the current supplied to the first servo motor and the second servo motor. Therefore, in the dual-drive control process of simultaneously controlling two servo motors using one power conversion unit, resonance suppression is controlled in real time, thereby ensuring stability and reliability of approximately 5.2 times against interference.

[0206] The detailed description of the present invention described above refers to the preferred embodiments of the present invention. However, any person skilled in the art or a person of ordinary skill in the art will understand that various modifications and changes may be made to the present invention without departing from the scope of the invention and the technical scope as described in the patent claims. Therefore, the technical scope of the present invention is not limited by the contents described in the detailed description of the specification, but is determined by the patent claims.

[0207] Explanation of symbols

[0208] 1: Resonance suppression control device, 10: First servo driver, 11: Second servo driver, 20: First inverter, 21: Second inverter, 30: First servo motor, 31: Second servo motor, 100: CNC unit, 200: Main operation unit, 300: PLC, 400: Servo driver, 410: Output unit, 411: Speed signal output unit, 412: Torque signal output unit, 420: Notch filter unit, 430: Notch filter control unit, 431: Notch filter control unit, 432: Notch filter control unit, 433: Notch filter control unit, 434: Notch filter control unit, 435: Notch filter control unit, 436: Notch filter control unit, 437: Notch filter control unit, 438: Notch filter control unit, 439: Notch filter control unit, 440: Notch filter control unit, 441: Notch filter control unit, 442: Notch filter control unit, 443: Notch filter control unit, 444: Notch filter control unit, 445: Notch filter control unit, 446: Notch filter control unit, 447: Notch filter control unit, 448: Notch filter control unit, 449: Notch filter control unit, 450: Notch filter control unit, 451: Notch filter control unit, 452: Notch filter control unit, 453: Notch filter control unit, 454: Notch filter control unit, 455: Notch filter control unit, 456: Notch filter control unit, 457: Notch filter control unit, 458: Notch filter control unit, 459: Notch filter control unit, 460: Notch filter control unit, 461: Notch filter control unit, 462: Notch filter control unit, 463: Notch filter control unit 1: Memory unit, 4311: Basic data storage unit, 4312: Feedback data storage unit, 4313: Real-time data storage unit, 432: Operation unit, 4321: Damping coefficient calculation unit, 4322: Natural frequency calculation unit, 4323: Pole calculation unit, 4324: Zero calculation unit, 4325: Coefficient calculation unit, 433: Instruction unit, 500: Power conversion unit, 600: Servo motor unit, 610: First servo motor, 620: Second servo motor.

Claims

1. A dual-drive control system for a machine tool, characterized in that: include: CNC department; Main operating unit; A PLC executes control instructions by communicating with the numerical control unit or the main operation unit; A servo driver having a notch filter unit and executing control instructions of the PLC; a servo motor unit driven according to the control of the servo driver; and a power conversion unit, electrically connected to the servo motor unit and the servo driver, for applying current to the servo motor unit; The servo driver adjusts the application state of the current transmitted to the power conversion unit according to the change of the notch filter coefficient calculated in real time by the notch filter unit, thereby performing resonance suppression caused by the operation of the servo motor unit. The servo drive comprises: an output unit for outputting an operating speed signal of the servo motor unit and a torque signal transmitted to the power conversion unit; and a notch filter control unit that calculates a notch filter coefficient of the notch filter unit in real time and controls whether to apply the current transmitted to the power conversion unit according to the calculated notch filter coefficient; The servo motor unit includes a first servo motor and a second servo motor connected in parallel. According to the real-time change of the notch filter coefficient of the notch filter unit, whether to apply the current transmitted to the first servo motor and the second servo motor respectively through the power conversion unit is adjusted in real time, thereby controlling the resonance suppression generated during the dual drive control process of the first servo motor and the second servo motor. The notch filter control unit includes: a memory unit storing dual-drive control information for suppressing resonance generated when the first servo motor and the second servo motor operate in parallel; a calculation unit that calculates a notch filter coefficient of the notch filter unit using the information stored in the memory unit; and The command unit cuts off the current supplied to the power conversion unit by the notch filter unit through a resonance damping command based on the result of the calculation unit, thereby performing resonance suppression in real time through dual drive control.

2. The dual-drive control system for a machine tool according to claim 1, characterized in that: The memory unit includes: a basic data storage unit for storing information related to a maximum value of magnetic flux linkage caused by corresponding permanent magnets, an angular velocity at an operating point, a DC gain of a notch filter unit, an inductance of a stator winding of a servo motor unit, a pole constant of the servo motor unit, a stator winding resistance of the servo motor unit, and a rotor inertia moment of the servo motor unit; a feedback data storage unit for storing position and speed feedback information of the first servo motor generated when the first servo motor and the second servo motor are operated in parallel, and position and speed feedback information of the second servo motor generated when the second servo motor and the first servo motor are operated in parallel; and The real-time data storage unit is used to store the real-time notch filter coefficient of the notch filter unit calculated by the calculation unit and the current resonance attenuation instruction output by the instruction unit.

3. The dual-drive control system for a machine tool according to claim 2, characterized in that: The computing unit includes: a damping coefficient calculation unit that calculates a damping coefficient of the servo motor unit based on the data stored in the basic data storage unit; a natural frequency calculation unit that calculates the natural frequency of the servo motor unit based on the data stored in the basic data storage unit; a pole calculation unit that calculates poles of the dual-drive control system based on the data stored in the basic data storage unit, the calculated value of the damping coefficient calculation unit, and the calculated value of the natural frequency calculation unit; a zero point calculation unit that calculates a zero point of the notch filter unit based on the data stored in the basic data storage unit, the calculated value of the damping coefficient calculation unit, and the calculated value of the natural frequency calculation unit; and The coefficient calculation unit calculates a notch filter coefficient based on the data stored in the basic data storage unit, the calculated value of the damping coefficient calculation unit, the calculated value of the natural frequency calculation unit, the calculated value of the pole calculation unit, and the zero point value of the zero point calculation unit.

4. The dual-drive control system for a machine tool according to claim 3, characterized in that: The instruction unit uses the data stored in the basic data storage unit, the calculated value of the damping coefficient calculation unit, the calculated value of the natural frequency calculation unit, the calculated value of the pole calculation unit, the zero point value of the zero point calculation unit, and the notch filter coefficient value of the calculation unit to output a resonance attenuation instruction through the zero-pole elimination technology.

5. The dual-drive control system for a machine tool according to claim 2, characterized in that: The output unit includes: a speed signal output unit that outputs an operating speed signal of the servo motor unit according to a position instruction received from the numerical control unit and a feedback signal received from the feedback data storage unit; and The torque signal output unit outputs an effective torque signal to be transmitted to the power conversion unit to drive the servo motor unit based on the speed signal received from the speed signal output unit and the feedback signal received from the feedback data storage unit.

6. A control method for a dual-drive control system of a machine tool, characterized in that: include: A step of storing basic data for a servo motor unit and a notch filter unit for dual drive control; Calculating the damping coefficient and natural frequency of the servo motor unit; Steps for calculating the poles of a dual-actuator control system; the step of calculating the zero point of the notch filter portion; a step of calculating a notch filter coefficient of the notch filter unit by using the stored basic data, the calculated damping coefficient and natural frequency of the servo motor unit, the poles of the dual-drive control system, and the zeros of the notch filter unit; The steps of executing control instructions in PLC through communication with the numerical control unit or main operation unit; The step of executing the control instruction transmitted from the PLC by the servo drive; A step of applying a current to a servo motor unit including a first servo motor and a second servo motor by a power conversion unit according to a signal from the servo driver; storing position and speed feedback information of the first servo motor generated when the first servo motor and the second servo motor are operated in parallel, and storing position and speed feedback information of the second servo motor generated when the second servo motor and the first servo motor are operated in parallel; as well as The step of outputting a resonance attenuation instruction in real time according to the calculated notch filter coefficient, The notch filter unit cuts off the current applied to the power conversion unit using the notch filter coefficient and the resonance damping command calculated in real time, thereby performing resonance suppression in real time through dual drive control.

7. The control method of the dual-drive control system of a machine tool according to claim 6, characterized in that: include: After outputting the resonance damping instruction, a step of storing the current notch filter coefficient calculated in real time and the resonance damping instruction output in real time.

Images