KR20230147328A - Master motor and slave motor switching control system in tandem control of machine tool and method thereof - Google Patents

Abstract

The present invention relates to a master motor and slave motor switching control system in tandem control of a machine tool and a control method thereof which drive one of a first motor unit and a second motor unit by a main motor unit and the other one by an auxiliary motor unit through tandem control of a servo drive and allow the first motor unit and the second motor unit to be selectively switched to the main motor unit and the auxiliary motor unit by comparing an input power angle and a reference value of a motor unit currently operating as the auxiliary motor unit under the control of the servo drive if an unbalanced load occurs during tandem control so as to perform stable speed control and increase system responsiveness and efficiency.

Description

Master motor and slave motor switching control system in tandem control of machine tool and method thereof}

The present invention relates to a main motor switching control system and a control method thereof in tandem control of a machine tool. More specifically, the first motor unit and the second motor unit are connected to the first motor unit and the second motor unit through tandem control of the servo drive. One of the parts is driven by the main motor part and the other part is driven by the auxiliary motor part. If an unbalanced load occurs during tandem control, the input power angle and reference value of the motor part currently operating as the auxiliary motor part are compared and the first motor part and the second motor part are driven. 2 This relates to a main motor switching control system and its control method in tandem control of a machine tool that can perform stable speed control by selectively switching between the main motor part and the auxiliary motor part according to the control of the servo drive.

In general, machine tools refer to machines used to process metal/non-metal workpieces into desired shapes and dimensions using appropriate tools using various cutting or non-cutting processing methods.

Various types of machine tools, including turning centers, vertical/horizontal machining centers, door machining centers, Swiss turns, electric discharge machines, horizontal NC boring machines, and CNC lathes, are widely used in various industrial fields to suit the purpose of the work.

In general, various types of machine tools currently in use are equipped with an operating panel to which numerical control (NC) or computerized numerical control (CNC) technology is applied. This operating panel is equipped with various function switches or buttons and a monitor.

In addition, a machine tool includes a table on which the workpiece material is seated and transported for processing the workpiece, a pallet to prepare the workpiece before processing, a spindle on which the tool or workpiece is combined and rotated, a tailstock to support the workpiece, etc. during processing, and an anti-vibration tool. Equipped with etc.

In general, in machine tools, tables, tool rests, spindles, tailstocks, vibration stoppers, etc. are equipped with transfer units that transfer along a transfer axis to perform various machining.

In addition, machine tools generally use multiple tools for various processing, and a tool magazine or turret is used as a tool storage location to store and store multiple tools.

In addition, machine tools are generally equipped with an automatic tool changer (ATC) to withdraw or re-store a specific tool from a tool magazine according to a command from a numerical control unit in order to improve the productivity of the machine tool.

Additionally, machine tools are generally equipped with an automatic pallet changer (APC) to minimize non-processing time. The automatic pallet changer (APC) automatically exchanges pallets between the workpiece machining area and the workpiece installation area. A workpiece can be mounted on a pallet.

In general, servo motors are used to drive automatic tool changers (ATC), automatic pallet changers (APC), tailstocks, or vibration isolation devices in machine tools.

In this way, the device that controls the servo motor (SERVO MOTOR) and ultimately controls the automatic tool changer (ATC), automatic pallet changer (APC), tailstock, or vibration isolator is called a servo control device.

In particular, in cases where the size is large or a large force is required, such as a large automatic pallet changer (APC), two servomotors are installed in parallel due to productivity and economic factors and technical factors in which sufficient torque cannot be obtained with only one servomotor. One axis is driven by driving, and this is called tandem control.

However, as shown in FIG. 1, when using two servo motors, the conventional servo control device combines one inverter and one servo drive with one servo motor, respectively. That is, the first inverter 20 and the first servo drive 10 are connected to the first servo motor 30, and the second inverter 21 and the second servo drive 11 are connected to the second servo motor 31. It was operated using a connected multi inverter multi servo motor.

However, in the case of multi-inverter multi-servomotors, a separate inverter and servo drive must be combined for each servo motor, which increases the size of the device, increases manufacturing and maintenance costs, and makes it impossible to miniaturize machine tools. there was.

To solve this problem, as shown in FIG. 2, a single inverter dual servomotor (Single inverter) is used in which one inverter (20) and one servo drive (10) are operated in parallel on two servo motors (30, 31). dual servo motor (SIDM) was proposed.

However, unlike induction motors that have slip, servomotors are permanent magnet synchronous motors that do not have slip, so stable parallel operation is possible only when two servomotors are synchronized so that there is no speed deviation. If not, the servo motors are driven through resonance and step-out. There was a problem in that the stability and reliability of the control device deteriorated, and ultimately, the stability, reliability, and processing precision of the machine tool deteriorated.

To solve this resonance suppression control problem, three conventional resonance suppression control systems and resonance suppression control methods have been proposed.

First, it is an attenuation control device and method using an auxiliary inverter and an auxiliary winding. This is a structure in which the main inverter and auxiliary inverter are separately provided and a servo motor and auxiliary winding are formed. The manufacturing cost increases due to the existing two inverters, and the mass Problems such as production difficulties still remain.

Second, as the resonance suppression control is set simply by empirical methods using an active damping control device and method, the reliability and stability of the servo control device are still guaranteed because the actual occurrence of resonance or many disturbances or variables cannot be actively dealt with. There is a problem that the manufacturing cost only increases.

Third, resonance suppression control is calculated empirically using a pulsation reduction device and method using a load oscillation analyzer. There is a problem in that the accuracy and reliability of resonance suppression control are reduced by simply calculating it using an empirical method, and ultimately, the machining precision and reliability of the machine tool are reduced.

In addition, Korean Patent Publication No. 10-2020-0025683 adjusts the control gain by checking the phase margin in the Bode plot obtained through frequency analysis, and Korean Patent Application No. 10-2019- No. 0170546 finds the resonance frequency and applies a notch filter to that frequency. Both types of tandem control have the disadvantage of lowering the responsiveness of the system as speed loop control is performed and being vulnerable to changes in system parameters.

However, as shown in FIGS. 1 and 2 and previous applications, the stability and reliability of the system are not maintained only by suppressing resonance in tandem control. Specifically, in order to stably operate two servomotors in parallel through tandem control, quick switching between the main motor unit and the auxiliary motor unit is required through analysis of dynamic characteristics according to load fluctuations.

For this purpose, in the conventional tandem control of machine tools, the main motor switching control system and its control method were implemented by applying dynamic characteristic analysis according to load fluctuations using the equal area method as shown in Figures 3 and 4 to perform tandem control.

Figure 3 is a graph of equal area according to load torque, and Figure 4 shows a graph of torque angle change in a transient state. In FIG. 3, the horizontal axis represents the torque angle (δ) between the terminal voltage and the excitation voltage, and the vertical axis represents torque (T). In FIG. 4, the horizontal axis represents time (t) and the vertical axis represents torque angle (δ). In FIGS. 3 and 4, δ is the torque angle, and δ represents the load torque angle.

Specifically, when the area A in the graph of FIG. 3 is smaller than the area B (A<B), the synchronous state is maintained in a stable state, and the torque angle (δ) in FIG. 4 becomes equal to Y.

In addition, when the area A in the graph of FIG. 3 is larger than the area B (A > B), the synchronization state is unstable and the torque angle (δ) continues to increase like X in FIG. 4.

Additionally, when the area A in the graph of FIG. 3 is equal to the area B (A=B), the system is in an unstable equilibrium state, and the torque angle (δ) in FIG. 4 is equal to Z.

However, in the tandem control of a machine tool using the conventional equal-area method, the main motor switching control system and its control method have many difficulties as the magnitude of the transient torque and the magnitude of the power angle must be determined to obtain the power angle of the real-time permanent magnet synchronous motor. There was a problem that processing productivity decreased due to time and cost being consumed.

In addition, in the tandem control of machine tools applying the conventional equal-area method, the main motor switching control system and its control method need to find the magnitude of the transient d-axis reactance in order to find the power angle, but magnetic saturation of the flux linkage due to the increase in armature current Due to this phenomenon, it is not easy to obtain the size of the d-axis reactance during the transient state, causing inconvenience to the operator, reducing precision, and deteriorating stability and reliability.

Moreover, in the tandem control of a machine tool using the conventional equal-area method, the main motor switching control system and its control method must calculate the area A and B in the graph in FIG. 3 in real time, and the amount of calculation of the servo drive must increase, so the system There were problems in that miniaturization could not be achieved, manufacturing costs increased, space utilization decreased, and stable speed control could not be performed.

Accordingly, when an unequal load occurs during tandem control, the input power angle of the auxiliary motor is calculated in real time using voltage and current information, and compared with the reference value, the current auxiliary motor is quickly converted to the main motor and the existing main motor to the auxiliary motor. There is an urgent need to develop a control system and control method for switching from main motor to tandem control of machine tools that can accurately switch.

Republic of Korea Patent Publication No. 10-2020-0025683 Republic of Korea Patent Publication No. 10-2021-0078769 Republic of Korea Patent Publication No. 10-1996-0001940 Republic of Korea Patent Publication No. 10-1995-0703812

The present invention is to solve the above problems, and the purpose of the present invention is to control the first motor unit and the second motor unit through tandem control of the servo drive, with one of the first motor unit and the second motor unit being the main motor unit. The remaining one is driven by the auxiliary motor unit, and when an unbalanced load occurs during tandem control, the first motor unit and the second motor unit automatically switch between the main motor unit and the auxiliary motor unit under the control of the servo drive, providing stable speed control. The purpose is to provide a control system and control method for switching from main motor to tandem control of machine tools that can improve system responsiveness and efficiency.

In addition, another object of the present invention is to control the input from the motor unit currently operating as the auxiliary motor unit among the first motor unit and the second motor unit when an unbalanced load occurs between the main motor unit and the auxiliary motor unit according to tandem control. After calculating the power angle in real time, if the calculated input power angle is greater than the standard value, the current auxiliary motor is automatically converted to the main motor and the existing main motor is automatically converted to the auxiliary motor. If the input power angle is equal to or smaller than the standard value, the current auxiliary motor is automatically converted to the main motor. By maintaining the auxiliary motor unit and the main motor unit, stable speed control is performed to improve the stability and reliability of the machine tool, reduce manufacturing costs, miniaturize by removing unnecessary equipment, and improve reliability by reducing noise. It provides a control system for switching from tandem control to main motor and its control method for machine tools that can improve performance and durability, and reduce maintenance and management costs.

In order to achieve the purpose of the present invention, the main motor switching control system in the tandem control of the machine tool according to the present invention includes a numerical control unit; main operation department; A PLC that executes control commands through communication with the numerical control unit or the main operation unit; A servo drive that executes control commands from the PLC; A servo motor unit including a first motor unit and a second motor unit connected in parallel to each other and driven by the servo drive; And a power conversion unit electrically connected to the servo motor unit and the servo drive to apply current to the servo motor unit through tandem control of the servo drive, wherein the first motor unit and the second motor unit are Through tandem control of the servo drive, one of the first motor unit and the second motor unit is driven as a main motor unit and the other one is driven as an auxiliary motor unit, and when an unbalanced load occurs, the first motor unit and the second motor unit are driven. 2 The motor unit can be selectively switched between the main motor unit and the auxiliary motor unit by comparing the input power angle and the reference value of the motor unit currently operating as the auxiliary motor unit under the control of the servo drive.

In addition, in another preferred embodiment of the main motor switching control system in tandem control of a machine tool according to the present invention, the servo drive of the main motor switching control system in tandem control of a machine tool currently operates the main motor unit and the auxiliary motor according to tandem control. When an unbalanced load occurs between the units, the input power angle from the motor unit currently operating as the auxiliary motor unit among the first motor unit and the second motor unit is calculated in real time, and the calculated input power angle is greater than the reference value. In this case, speed control can be performed by automatically switching the current auxiliary motor unit to the main motor unit and the existing main motor unit to the auxiliary motor unit.

In addition, in another preferred embodiment of the main motor switching control system in tandem control of a machine tool according to the present invention, the servo drive of the main motor switching control system in tandem control of a machine tool switches on the first motor when an unbalanced load occurs. a memory unit that stores data for automatically switching the motor unit and the second motor unit to a main motor unit and an auxiliary motor unit under control of the servo drive; a calculation unit that checks whether an unbalanced load occurs through data stored in the memory unit and calculates an input power angle of a motor unit currently operating as an auxiliary motor unit among the first motor unit and the second motor unit; and a switching unit that determines whether to switch between the current auxiliary motor unit and the main motor unit according to tandem control according to the data stored in the memory unit and the calculation result of the calculation unit.

In addition, in another preferred embodiment of the main motor switching control system in tandem control of a machine tool according to the present invention, the memory unit of the servo drive of the main motor switching control system in tandem control of a machine tool includes a reference value, terminal voltage, excitation voltage, A basic data storage unit that stores information about synchronous reactance and synchronous angular velocity; A collection data storage unit that stores data on motor speed, magnet flux, D-axis current, Q-axis current, maximum input power, maximum output power, and stator resistance; and a real-time data storage unit that stores the results of the calculation unit and the conversion unit in real time.

In addition, in another preferred embodiment of the main motor switching control system in tandem control of a machine tool according to the present invention, the operation unit of the servo drive of the main motor switching control system in tandem control of a machine tool includes the first motor unit and the first motor unit. 2 A confirmation unit that checks whether an unbalanced load occurs when one motor unit operates as a main motor unit and the other as an auxiliary motor unit through tandem control; an input power calculation unit that calculates the current input power of the auxiliary motor unit through data stored in the memory unit when an unbalanced load occurs as a result of the verification unit; an output power calculation unit that calculates the current output power of the auxiliary motor unit using the input power calculated by the input power calculation unit and data stored in the memory unit; and an input power angle calculation unit that calculates the current input power angle of the auxiliary motor unit according to the input power calculated by the input power calculation unit, the output power calculated by the output power calculation unit, and the data stored in the memory unit. may include.

In addition, in another preferred embodiment of the main motor switching control system in tandem control of a machine tool according to the present invention, the switching unit of the servo drive of the main motor switching control system in tandem control of a machine tool calculates the input power angle through the calculation unit. a comparison unit that compares the current input power angle of the auxiliary motor unit with data stored in the memory unit; And, as a result of the comparison of the comparison unit, if the input power angle of the current auxiliary motor unit calculated through the input power angle calculation unit is greater than the reference value, the current auxiliary motor unit is automatically converted to the main motor unit and the existing main motor unit is automatically converted to the auxiliary motor unit, and the input power angle is automatically converted to the main motor unit. If the input power angle of the current auxiliary motor unit calculated through each calculation unit is less than or equal to the reference value, a selection unit that maintains the current auxiliary motor unit and the main motor unit as is.

In addition, in another preferred embodiment of the main motor switching control system in tandem control of a machine tool according to the present invention, the input power angle calculation unit of the servo drive of the main motor switching control system in tandem control of a machine tool is configured to operate the auxiliary motor in a normal state. The calculation can be performed with the magnitude of the negative input power and output power being the same and the resistance component being ignored.

In addition, in another preferred embodiment of the main motor switching control system in tandem control of a machine tool according to the present invention, the servo drive of the main motor switching control system in tandem control of a machine tool includes the memory unit, the operation unit, and the switching unit. It may further include a display unit that displays a negative result.

In order to achieve another object of the present invention, the main motor switching control method in tandem control of a machine tool according to the present invention is to switch the first motor unit and the second motor unit between the main motor unit and the second motor unit under the control of the servo drive when an unbalanced load occurs. Storing data for automatically switching between auxiliary motor units; Executing control commands in a PLC through communication with a numerical control unit or main operation unit; Executing a control command transmitted from the PLC by the servo drive; Among the first motor unit and the second motor unit, one is primarily selected as a main motor unit and the other is primarily selected as an auxiliary motor unit, and the selected main motor unit and the auxiliary motor unit are controlled in tandem through the servo drive; Checking whether an unbalanced load occurs when the first motor unit and the second motor unit are controlled in tandem, with one currently operating as a main motor unit and the other motor unit as an auxiliary motor unit; As a result of confirmation, if an unbalanced load occurs, calculating the current input power of the auxiliary motor unit through pre-stored data; Calculating the current output power of the auxiliary motor unit using the calculated input power and previously stored data; calculating the current input power angle of the auxiliary motor unit according to the calculated input power, the calculated output power, and previously stored data; Comparing the calculated current input power angle of the auxiliary motor unit with a pre-stored reference value; and automatically converting the current auxiliary motor unit to the main motor unit and the existing main motor unit to the auxiliary motor unit according to the comparison result, or selecting whether to maintain the current auxiliary motor unit and the main motor unit as is.

In addition, in another preferred embodiment of the main motor switching control method in tandem control of a machine tool according to the present invention, the selection step of the main motor switching control method in tandem control of a machine tool is determined by the calculated current input power angle of the auxiliary motor unit. If it is greater than the standard value, the current auxiliary motor unit is automatically converted to the main motor unit and the existing main motor unit is automatically converted to the auxiliary motor unit. If the calculated input power angle of the current auxiliary motor unit is less than or equal to the standard value, the current auxiliary motor unit and main motor unit are left as is. It can be maintained.

In the tandem control of a machine tool according to the present invention, the main motor switching control system and its control method have the first motor unit and the second motor unit through tandem control of the servo drive, and one of the first motor unit and the second motor unit is the main motor unit. The remaining motor unit is driven by the auxiliary motor unit, and when an unbalanced load occurs during tandem control, the first motor unit and the second motor unit automatically switch between the main motor unit and the auxiliary motor unit under the control of the servo drive, ensuring stable speed. It reduces manufacturing costs by performing control, improves reliability by improving stability, and can be used universally regardless of the type and capacity of the servomotor, so it is a control system for switching from tandem control of machine tools to a main motor and its control method. It has the effect of increasing compatibility.

In addition, in tandem control of a machine tool according to the present invention, the main motor switching control system and its control method assist with the current main motor unit when tandem controlling two servo motors such as parallel operation by one power unit and a power conversion unit. In the case where an unbalanced load occurs between the motor units, the input power angle from the motor unit currently operating as the auxiliary motor unit among the first motor unit and the second motor unit is calculated in real time, and the calculated input power angle is greater than the reference value. The current auxiliary motor unit is automatically converted to the main motor unit and the existing main motor unit is automatically converted to the auxiliary motor unit. If the input power angle is equal to or smaller than the standard value, the subdrive performs tandem control to maintain the current auxiliary motor unit and main motor unit as is. Accordingly, by removing unnecessary components, the tandem control system of the machine tool can be miniaturized and space utilization can be maximized.

Moreover, in tandem control of a machine tool according to the present invention, the main motor switching control system and its control method change the input power angle of the auxiliary motor unit according to the unbalanced load that occurs in real time according to the operation status of the servo motor unit according to the tandem control of the servo drive. It automatically calculates in real time and compares it with the reference value to quickly and automatically select whether to switch between the main motor unit and the auxiliary motor unit to perform tandem control, thereby increasing system responsiveness and maintaining robust characteristics against changes in system parameters. It has the effect of maximizing the precision and reliability of the servo control device of the tool changer or automatic pallet changer, and increasing the stability and processing efficiency of the machine tool.

In addition, in tandem control of a machine tool according to the present invention, the main motor switching control system and its control method are used to determine the type of servo motor when an unbalanced load occurs when two servo motors are operated in parallel by one power unit and a power conversion unit. Regardless of capacity, it automatically converts the current auxiliary motor unit to the main motor unit in real time or performs tandem control while maintaining the existing status, thereby promoting operator convenience and minimizing non-processing time to maximize machine tool productivity. There is a possible effect.

Figure 1 shows a conceptual diagram of a multi-inverter multi-servo motor in which one inverter and one servo drive are combined with one conventional servo motor.
Figure 2 shows a conceptual diagram of a single inverter multi-servo motor in which tandem control is performed by combining two conventional servomotors with one inverter and one servo drive.
Figure 3 shows a graph of equal area according to load torque.
Figure 4 shows a graph of torque angle trend in a transient state.
Figure 5 shows a block diagram of the configuration of a main motor switching control system in tandem control of a machine tool according to an embodiment of the present invention.
Figure 6 shows a block diagram of the configuration of the servo drive of the main motor switching control system in tandem control of a machine tool according to an embodiment of the present invention.
Figure 7 shows a procedure diagram of a main motor switching control method in tandem control of a machine tool according to an embodiment of the present invention.
Figure 8 shows a graph for stability analysis of the power angle of a permanent magnet synchronous electric motor.
Figure 9 shows a graph for confirming the speed response characteristics to an unbalanced load between two permanent magnet synchronous motors.
FIG. 10 shows an enlarged graph of portion K of FIG. 9.
FIG. 11 shows an enlarged graph of portion J of FIG. 9.

Hereinafter, the main motor switching control system and its control method in tandem control of a machine tool according to an embodiment of the present invention will be described in detail with reference to the drawings. The embodiments introduced below are provided as examples so that the idea of the present invention can be sufficiently conveyed to those skilled in the art. Accordingly, the present invention is not limited to the embodiments described below and may be embodied in other forms. Also, in the drawings, the size and thickness of the device may be exaggerated for convenience. Like reference numerals refer to like elements throughout the specification.

The advantages and features of the present invention and methods for achieving them will become clear by referring to the embodiments described in detail below along with the accompanying drawings. However, the present invention is not limited to the embodiments disclosed below and will be implemented in various different forms. These embodiments only serve to ensure that the disclosure of the present invention is complete and that common knowledge in the technical field to which the present invention pertains is provided. It is provided to fully inform those who have the scope of the invention, and the present invention is only defined by the scope of the claims. Like reference numerals refer to like elements throughout the specification. The sizes and relative sizes of layers and regions in the drawings may be exaggerated for clarity of explanation.

The terminology used herein is for describing embodiments and is therefore not intended to limit the invention. As used herein, singular forms also include plural forms, unless specifically stated otherwise in the context. As used in the specification, “comprise” and/or “comprising” refers to the presence of one or more other components, steps, operations and/or elements. or does not rule out addition.

Figure 5 shows a block diagram of the configuration of the main motor switching control system in tandem control of a machine tool according to an embodiment of the present invention, and Figure 6 shows a block diagram of the main motor switching control system in tandem control of a machine tool according to an embodiment of the present invention. It shows a block diagram of the servo drive configuration of the conversion control system. Figure 7 shows a procedure diagram of a main motor switching control method in tandem control of a machine tool according to an embodiment of the present invention. Figure 8 shows a graph for stability analysis of the power angle of a permanent magnet synchronous electric motor. Figure 9 shows a graph for confirming the speed response characteristics for unbalanced load between two permanent magnet synchronous motors, Figure 10 shows an enlarged graph of part K of Figure 9, and Figure 11 shows an enlarged graph of part J of Figure 9. Shows a graph.

5 to 6 and 8 to 11, the main motor switching control system 1 in tandem control of a machine tool according to the present invention will be described. As shown in Figures 5 and 6, in tandem control of a machine tool according to an embodiment of the present invention, the main motor switching control system 1 includes a numerical control unit 100, a main operation unit 200, a PLC 300, It includes a servo drive 400, a servo motor unit 600, and a power conversion unit 500.

The numerical control unit 100 includes a numerical control (NC) or computerized numerical control (CNC) and has various numerical control programs built in. That is, the numerical control unit 100 is equipped with a drive program for the servomotor unit, a tool operation program, etc., and the corresponding program is automatically loaded and operated as the numerical control unit is driven. Additionally, the numerical control unit 100 communicates with the main manipulation unit 200, PLC 300, and servo drive 400 using a predetermined protocol.

In addition, the numerical control unit 100 includes a first motor unit 610 and/or It receives collected information according to the operation and feedback information about the processing results of the calculation unit from the second motor unit 620. More specifically, the numerical control unit 100 is configured from the collected data storage unit of the memory unit and the basic data storage unit to be described later, the feedback data storage unit of the storage unit of the d-axis current control unit of the first motor unit or the second motor unit, and the main motor unit or auxiliary motor unit. It receives collected information and feedback information about terminal voltage, excitation voltage, synchronous reactance, synchronous angular speed, motor speed, magnetic flux of magnet, D-axis current, Q-axis current, maximum input power, maximum output power, and stator resistance position.

The main operation unit 200 includes a screen display program and a data input program according to screen display selection, displays a software switch on the display screen according to the output of the screen display program, and turns the software switch on/off. It performs the function of recognizing and issuing input/output commands for machine operation.

In addition, although not necessarily limited to this, the main operating unit 200 is installed in the housing, case, or one side of the machine tool and includes various function switches or buttons and a monitor capable of displaying various information. In other words, monitors include liquid crystal displays (LCD), thin film transistor-liquid crystal displays (TFT LCD), organic light-emitting diodes (OLED), and flexible displays. , a 3D display, or an electronic ink display, and may be formed in a touch screen form.

The PLC (Programmable Logic Controller, 300) performs communication with the numerical control unit 100 or the main operation unit 200 according to a predetermined protocol, and performs the function of executing control commands through this communication. That is, the PLC 300 operates by receiving control commands according to the numerical control program of the numerical control unit 100 or the main operation unit 200.

In addition, after receiving control commands from the numerical control unit 100 or the main manipulation unit 200 and executing them, the PLC 300 outputs them to the numerical control unit 100 and sends the control commands to the servo drive through the main manipulation unit 200. Deliver to (400). If necessary, the PLC 300 may transmit real-time control commands from the user to the servo drive 400 through the main operation unit 200.

The servo drive 400 executes control commands from the PLC (300). That is, the servo drive 400 uses control commands from the PLC 300 to control one of the first and second motor units of the servo motor unit 600, which will be described later, as the master motor, and the other motor unit. Select the auxiliary motor unit (Slave motor) to control the operation of the current main motor unit and auxiliary motor unit, and finally, the automatic tool changer (ATC) or automatic pallet changer (APC) driven by the main motor unit and auxiliary motor unit. ), controls the operation of various parts of machine tools such as tailstock and vibration stop. The servo drive 400 transmits the control result to the PLC 300 through a contact or communication using a predetermined protocol.

In addition, the servo drive 400 is currently the main motor unit and the auxiliary motor unit among the first motor unit and the second motor unit of the servo motor unit 600 used to drive the automatic tool changer (ATC) or the automatic pallet changer (APC). It receives various collected information and feedback information about the motor units that operate as a motor unit.

The servo motor unit 600 is driven through tandem control of the servo drive 400. As shown in FIG. 5, in tandem control of a machine tool according to an embodiment of the present invention, the servomotor unit 600 of the main motor switching control system 1 includes a first motor unit 610 connected in parallel with each other, It is provided with a second motor unit 620, and both the first motor unit and the second motor unit are formed as servo motors. In addition, the master motor and slave motors change in real time depending on the operation status of the servo motor according to the tandem control of the servo drive.

The power conversion unit 500 is electrically connected to the servo motor unit 600 and the servo drive 400. In addition, the power conversion unit 500 applies current to the servo motor unit 600 through tandem control according to the contact signal of the servo drive 400.

In the servo motor unit, one of the first and second motor units is driven as the main motor unit and the other as an auxiliary motor unit through tandem control of the servo drive, and an unbalanced load is generated. In this case, the first motor unit and the second motor unit selectively switch to the main motor unit and the auxiliary motor unit by comparing the input power angle and the reference value of the motor unit currently operating as the auxiliary motor unit under the control of the servo drive.

In other words, the main motor unit and the auxiliary motor unit are not specifically designated, but are connected in parallel according to the tandem control of the servo drive and are changed in real time according to the load amount of the main motor unit and the auxiliary motor unit operating through synchronization.

Specifically, when an unbalanced load occurs between the main motor unit and the auxiliary motor unit according to tandem control, the servo drive monitors the input power angle in real time from the motor unit currently operating as the auxiliary motor unit among the first motor unit and the second motor unit. After calculation, if the calculated input power angle is greater than the reference value, the current auxiliary motor unit is automatically converted to the main motor unit and the existing main motor unit is automatically converted to the auxiliary motor unit to perform speed control according to tandem control.

In this way, in tandem control of a machine tool according to the present invention, the main motor switching control system and its control method assist with the current main motor unit when tandem controlling two servo motors such as parallel operation by one power unit and a power conversion unit. In the case where an unbalanced load occurs between the motor units, the input power angle from the motor unit currently operating as the auxiliary motor unit among the first motor unit and the second motor unit is calculated in real time, and the calculated input power angle is greater than the reference value. The current auxiliary motor unit is automatically converted to the main motor unit and the existing main motor unit is automatically converted to the auxiliary motor unit. If the input power angle is equal to or smaller than the standard value, the subdrive performs tandem control to maintain the current auxiliary motor unit and main motor unit as is. This reduces manufacturing costs, improves reliability by improving stability, and can be used universally regardless of the type and capacity of the servomotor, increasing the compatibility of the main motor conversion control system and its control method in tandem control of machine tools. By removing unnecessary components, the tandem control system of the machine tool can be miniaturized and space utilization can be maximized.

As shown in Figures 5 and 6, in tandem control of a machine tool according to the present invention, the servo drive 400 of the main motor switching control system 1 includes a memory unit 410, a calculation unit 420, and a switching unit 430. ), and/or a display unit 440.

Although not shown in the drawing, the servo drive 400 of the main motor switching control system in tandem control of a machine tool may additionally include a controller as needed. This controller is installed inside the servo drive 400, and a detailed control command decoding program, various processing programs, and driving programs are separately built in. In addition, the controller communicates with the numerical control unit 100, the main operation unit 200, the PLC 300, the servomotor unit 600, and the power conversion unit 500 using a predetermined protocol.

If necessary, the main operation unit 200 can directly transmit the control commands of the main operation unit to the servo drive 400 through the PLC 300 without going through the numerical control unit 100.

In this way, since the detailed control command decoding program and separate control program are all built into the controller of the servo drive 400, which will be described later, the main operation unit ( The servo drive 400 may execute commands through 200 and the PLC 300 to drive the servo motor unit 600, which will be described later.

Therefore, detailed control commands from the numerical control unit 100 can be performed by the controller of the servo drive 400, making it possible to perform the servo drive function by programming only other numerical control units and protocol functions. Through this, various programs can be run, maximizing equipment compatibility and promoting user convenience.

The memory unit 410 stores data for automatically switching the first motor unit and the second motor unit to the main motor unit and the auxiliary motor unit under the control of the servo drive when an unbalanced load occurs. This memory unit 410 may be a variety of storage devices such as ROM, RAM, EPROM, flash drive, hard drive, etc., or may be web storage that performs the storage function of the storage unit on the Internet. When an unbalanced load occurs in the memory unit, the task of storing information for tandem control to automatically switch the first motor unit and the second motor unit to the main motor unit and the auxiliary motor unit under the control of the servo drive is performed by the operator using the numerical control unit. Alternatively, it can be performed through the main operation unit and saved in program form through the PLC or input unit.

The calculation unit 420 checks whether an unbalanced load occurs through data stored in the memory unit and calculates the input power angle of the motor unit currently operating as the auxiliary motor unit among the first motor unit and the second motor unit.

The switching unit 430 determines whether to switch between the current auxiliary motor unit and the main motor unit according to tandem control according to the data stored in the memory unit and the calculation result of the calculation unit.

The display unit 440 displays the results of the memory unit, calculation unit, and conversion unit. These display units include liquid crystal display (LCD), thin film transistor-liquid crystal display (TFT LCD), organic light-emitting diode (OLED), and flexible display. , a 3D display, or an e-ink display.

In addition, although not necessarily limited to this, the display unit is formed in the form of a touch screen and can be installed in the housing, case, or one side of the servo drive to display various function switches or buttons and various information.

The memory unit 410, the calculation unit 420, and the switching unit 430 are installed inside the servo drive, and detailed control command decoding programs, various processing programs, and driving programs may be separately built in.

In addition, the memory unit 410, the calculation unit 420, the switching unit 430, and the display unit 440 include the numerical control unit 100, the main operation unit 200, the PLC 300, the servo motor unit 600, and the power Communication can be performed with the conversion unit 500 using a predetermined protocol.

As shown in Figure 6, in tandem control of a machine tool according to the present invention, the memory unit 410 of the servo drive 400 of the main motor switching control system 1 includes a basic data storage unit 411 and a collection data storage unit. (412), and a real-time data storage unit (413).

The basic data storage unit 411 stores information about the reference value, terminal voltage (V _t ), excitation voltage (E _f ), synchronous reactance (X _s ), and synchronous angular velocity (ω _s ).

The collection data storage unit 412 includes motor speed (ω _r ), magnetic flux of the magnet (ϕ _a ), D-axis current (i ^r _ds ), Q-axis current (i ^r _qs ), maximum input power (P _{in_max} ), and maximum Stores data on output power (P _{out_max} ) and stator resistance (R _s ).

The real-time data storage unit 413 stores the results of the calculation unit and the conversion unit in real time. That is, the real-time data storage unit stores the results of the confirmation unit, input power calculation unit, output power calculation unit, input power angle calculation unit, comparison unit, and selection unit of the calculation unit described later in real time.

As shown in Figure 6, in tandem control of a machine tool according to the present invention, the calculation unit 420 of the servo drive 400 of the main motor switching control system 1 includes a confirmation unit 421 and an input power calculation unit 422. , an output power calculation unit 423, and an input power angle calculation unit 424.

The confirmation unit 421 checks whether an unbalanced load occurs when the first motor unit and the second motor unit are currently operating as a main motor unit and the other as an auxiliary motor unit through tandem control.

The input power calculation unit 422 calculates the current input power (P _in ) of the auxiliary motor unit through the data stored in the memory unit when an unbalanced load occurs as a result of the verification unit. Specifically, if an unbalanced load occurs as a result of the confirmation of the confirmation unit, the input power calculation unit 422 calculates the current input power of the auxiliary motor unit through Equation 3, described later, using the data stored in the basic data storage unit and the collection data storage unit.

The output power calculation unit 423 calculates the current output power (P _out ) of the auxiliary motor unit using the input power calculated through the input power calculation unit and the data stored in the memory unit. Specifically, the output power calculation unit 423 calculates the input power (P _in ) calculated through the input power calculation unit and the current output power (P _out ) of the auxiliary motor unit through the data stored in the basic data storage unit and the collection data storage unit, as described later. It is calculated through Equation 4.

The input power angle calculation unit 424 determines the current auxiliary motor according to the input power (P _in ) calculated by the input power calculation unit, the output power (P _out ) calculated by the output power calculation unit, and the data stored in the memory unit. Calculate the negative input power angle (δ _in ). Specifically, the input power angle calculation unit 424 includes the input power (Pin) calculated by the input power calculation unit, the output power (P _out ) calculated by the output power calculation unit, and the basic data storage unit and the collected data storage unit. The current input power angle (δ _in ) of the auxiliary motor unit is calculated through Equation 6, described later, using the data stored in .

In addition, in order to derive quick and rapid response while maintaining accuracy and stability, it is not necessarily limited to this, but according to a preferred embodiment of the present invention, the input power angle calculation unit calculates the input power and output power of the auxiliary motor unit in a normal state. Calculation is performed using Equation 7, described later, with the same size and ignoring the resistance component.

As shown in Figure 6, in tandem control of a machine tool according to the present invention, the switching unit 430 of the servo drive 400 of the main motor switching control system 1 includes a comparing unit 431 and a selecting unit 432. Includes.

The comparison unit 431 compares the current input power angle of the auxiliary motor unit calculated through the input power angle calculation unit with data stored in the memory unit. Specifically, the comparison unit compares the current input power angle (δ _in ) of the auxiliary motor unit calculated through the input power angle calculation unit with the reference value stored in the basic data storage unit.

If the input power angle (δ _in ) of the current auxiliary motor unit calculated through the input power angle calculation unit as a result of the comparison of the comparison unit is greater than the reference value, the selection unit 432 automatically converts the current auxiliary motor unit to the main motor unit and the existing main motor unit to the auxiliary motor unit. Convert it to In addition, the selection unit maintains the current auxiliary motor unit and the main motor unit as is when the input power angle (δ _in ) of the current auxiliary motor unit calculated through the input power angle calculation unit as a result of the comparison of the comparison unit is less than or equal to the reference value. That is, the selection unit transmits a switching signal or a maintenance signal to the power conversion unit, and the power conversion unit applies current to the servomotor unit according to the signal to switch or maintain the main motor unit and the auxiliary motor unit of the first motor unit and the second motor unit. The operation is performed.

With reference to FIGS. 3 to 6 and FIGS. 8 to 11, the main motor switching control principle in tandem control of a machine tool according to the present invention will be explained.

As described above, when performing tandem control with two motor units connected in parallel as a main motor unit and an auxiliary motor unit, if an unbalanced load occurs, stable control is not performed.

Specifically, during tandem control, the main control target is the master motor, which is the master motor, and the slave motor, which is the auxiliary motor, is not controlled. However, if an unbalanced load occurs in the auxiliary motor, stable control may not be performed. do.

That is, in Figure 8, the horizontal axis represents the torque angle and the vertical axis represents the torque. As shown in Figure 8, stability analysis according to motor power angle is derived through Equations 1 and 2.

That is, the mechanical output torque (steady state) relative to the output power is derived from Equation 1 below.

[Equation 1]

Additionally, when the torque is suddenly changed, the transient torque is derived through Equation 2 below.

[Equation 2]

Here, V _t is the terminal voltage, E _f is the excitation voltage, X _s is the synchronous reactance, ω _s is the synchronous angular velocity, and δ is the torque angle between the terminal voltage and the excitation voltage.

These data are collected in real time through the basic data storage unit and the collected data storage unit and are updated through feedback.

As shown in Figure 8, when an unbalanced load occurs, the parameter of the motor unit that changes first is the power angle. As shown in Figure 8, the torque angle (δ) oscillates near the load torque angle (δ _L ) and when it reaches a steady state, δ'=δ _L. If the _δ'max value generated in a transient state exceeds the maximum of 90 degrees, an accident occurs due to step-out.

Specifically, when T _e is the motor torque, T _L is the load torque, T _max is the maximum torque produced by the motor, and δ is the power angle, the state without load is expressed by Equation 1 through Equation 8, and the state with load is is expressed as equation 9 through equations 1 and 2.

[Equation 8]

Motor torque T _e = T _max SINδ at no load

[Equation 9]

Motor torque under load T _e + T _L = T _max SINδ'

In Equations 8 and 9 above, assuming a stable state of 90 degrees or less as shown in Figure 8, the power angle δ' when there is a load is in the form of a SIN graph, so it is clearly larger than the power angle δ when there is no load. This happens. In other words, as can be seen from Equations 8 and 9, the existence of load torque can be immediately confirmed by the change in power angle.

Based on this principle, the main motor switching control system and control method in tandem control of a machine tool according to the present invention captures the load torque in real time by the power angle of the auxiliary motor part in the fastest, most accurate and stable manner when an unbalanced load occurs. Calculation of the input power angle (δ _in ) is required as a possible parameter.

To this end, the verification unit analyzes and checks the data stored in the basic data storage unit, the collected data storage unit, and the real-time data storage unit to determine whether an unbalanced load occurs.

If an unbalanced load occurs as a result of the confirmation in the confirmation unit, the current input power of the auxiliary motor unit is calculated through Equation 3 below in the input power calculation unit.

[Equation 3]

Afterwards, since the mechanical output is the last term in Equation 3, the output power is derived as in Equation 4, and the input power calculated through the input power calculation unit and the data stored in the basic data storage unit, the collected data storage unit, and the real-time data storage unit are The current output power of the auxiliary motor unit is calculated through Equation 4 below in the output power calculation unit.

[Equation 4]

Based on the above-mentioned Equation 4, the input power angle and output power angle are expressed as Equation 5 below.

[Equation 5]

By organizing Equation 4 above, Equation 6 is obtained, and the input power angle can be obtained in real time. That is, the input power calculated by Equation 3 by the input power angle calculation unit, the output power calculated by Equation 4 by the output power calculation unit, and the basic data storage unit, the collected data storage unit, and the real-time data. According to the data stored in the storage unit, the current input power angle of the auxiliary motor unit can be calculated through Equation 6.

[Equation 6]

In addition, in order to derive quick and rapid response while maintaining accuracy and stability, the input power angle calculation unit determines the input power and output power of the auxiliary motor unit in the normal state, and calculates the input power through Equation 7 below while ignoring the resistance component. Perform angle calculations.

[Equation 7]

Here, terminal voltage (V _t ), excitation voltage (E _f ), synchronous reactance (X _s ), synchronous angular velocity (ω _s ), motor speed (ω _r ), magnetic flux of magnet (ϕ _a ), and D-axis current (i ^r _ds ), Q-axis current (i ^r _qs ), maximum input power (P _{in_max} ), maximum output power (P _{out_max} ), stator resistance (R _s ), input power (P _in ), output power (P _out ), The input power angle (δ _in ), is.

Afterwards, when the input power angle of the current auxiliary motor unit is calculated according to Equation 6 or 7 in the input power angle calculation unit, the comparison unit compares the reference value stored in the basic data storage unit with the current input power angle of the auxiliary motor unit. .

Afterwards, if the input power angle of the current auxiliary motor unit calculated through the input power angle calculation unit as a result of the comparison of the comparison unit in the selection unit is greater than the standard value, the current auxiliary motor unit is automatically converted to the main motor unit and the existing main motor unit is automatically converted to the auxiliary motor unit, and the input If the input power angle of the current auxiliary motor unit calculated through the power angle calculation unit is less than or equal to the reference value, the current auxiliary motor unit and main motor unit are maintained as is.

Figure 9 shows the rated speed of both motor units (V) in an unloaded state to confirm the speed response characteristics to an unbalanced load between the two permanent magnet synchronous motor motor units of the first motor unit and the second motor unit connected in parallel with each other. Apply the 4000rpm command, and when the speed reaches the rated speed, load torque of 50% of the rated torque is applied only to M2 (master motor, main motor part), released after 2 seconds, and then again 2 seconds later to M1 (slave motor, auxiliary motor part). When 50% of the rated torque is applied as load torque to the motor unit only, a graph is shown for the time (time, ms) on the horizontal axis and the speed (speed, r/mim) on the vertical axis. FIG. 10 is a detailed graph of part K of FIG. 9 and FIG. 11 is a detailed graph of part J of FIG. 9, showing a graph of time (time, ms) on the horizontal axis and speed (speed, r/mim) on the vertical axis.

As shown in Figures 9 and 10, 2 is output at the beginning when the select signal (S) reaches the rated speed, which means that M2 operates as a master motor, and in part K of Figure 9, it operates as a master motor. Even when load torque is applied only to M2, M2 continues to be controlled in master mode.

As shown in FIGS. 9 to 11, 50% of the rated torque is applied as a load torque only to M1, which is the slave motor, in the J portion of FIG. 9, and the select signal (S) changes from 2 to 1, thereby making M1 the master. It shows control by changing to a motor.

Specifically, the transient speed response to such a load change (generating an unbalanced load) is as shown in Figure 11. The speed of M2, which has been changed from a master motor to a slave motor, is after vibrating for 60 ms around the speed of M1, which has been converted from a conventional slave motor to a master motor. It can be seen that the steady state has been reached.

As can be seen from the actual experiments shown in FIGS. 9 to 11, the main motor switching control system in the tandem control of the machine tool according to the present invention is an unbalance that occurs in real time depending on the operation status of the servo motor unit according to the tandem control of the servo drive. Depending on the load, the input power angle of the auxiliary motor unit is automatically calculated in real time and compared with the reference value to quickly and automatically select whether to switch between the main motor unit and the auxiliary motor unit to perform tandem control, ensuring stable speed control even under unbalanced load changes. possible.

In addition, in the tandem control of a machine tool according to the present invention, the main motor switching control system increases system responsiveness and has robust characteristics against changes in system parameters, thereby improving the precision of the servo control device of the automatic tool changer or automatic pallet changer. It maximizes reliability and increases the stability and processing efficiency of machine tools, and when an unbalanced load occurs when two servo motors are operated in parallel by one power unit and power conversion unit, regardless of the type and capacity of the servo motors. By automatically converting the current auxiliary motor unit to the main motor unit in real time or performing tandem control while maintaining the existing status, it is possible to improve the convenience of workers and maximize the productivity of machine tools by minimizing non-processing time.

As shown in Figure 7, the main motor switching control method in tandem control of a machine tool according to an embodiment of the present invention includes a data storage step (S1), a PLC execution step (S2), a servo drive operation step (S3), and a main motor Taboo/auxiliary motor unit first selection step (S4), confirmation step (S5), input power calculation step (S6), output power calculation step (S7), input power angle calculation step (S8), comparison step (S9), and a selection step (S10). In each step, the specific performance or content of the system or device is the same as the main motor switching control system in the tandem control of the machine tool in the specification of the present invention, and hereinafter, the control of the tandem control system of the machine tool will be described with reference to FIGS. 7 to 11. The unique features of the method are explained with emphasis.

When an unbalanced load occurs, data is stored to automatically convert the first motor unit and the second motor unit into a main motor unit and an auxiliary motor unit under the control of the servo drive.

After the data storage step (S1), control commands are executed in the PLC through communication with the numerical control unit or main operation unit.

After the PLC execution step (S2), the control command transmitted from the PLC is executed by the servo drive.

After the servo drive operation step (S3), one of the first motor unit and the second motor unit is primarily selected as the main motor unit and the other one is primarily selected as the auxiliary motor unit, and the selected main motor unit and the auxiliary motor unit are selected through the servo drive. Tandem control is performed. That is, when tandem control is performed through a servo drive, one of the first and second motor units is primarily selected as the main motor unit and the other is primarily selected as the auxiliary motor unit.

After the first selection step (S4) of the main motor unit/auxiliary motor unit, the first motor unit and the second motor unit are controlled in tandem, resulting in an unbalanced load when one currently operates as the main motor unit and the other as the auxiliary motor unit. Check whether

After the confirmation step (S5), if an unbalanced load occurs as a result of the confirmation, the current input power of the auxiliary motor unit is calculated using previously stored data.

After the input power calculation step (S6), the current output power of the auxiliary motor unit is calculated using the calculated input power and previously stored data.

After the output power calculation step (S7), the current input power angle of the auxiliary motor unit is calculated according to the calculated input power, calculated output power, and previously stored data.

After the input power angle calculation step (S8), the calculated current input power angle of the auxiliary motor unit is compared with a previously stored reference value.

After the comparison step (S9), depending on the comparison result, it is selected whether to automatically convert the current auxiliary motor unit to the main motor unit and the existing main motor unit to the auxiliary motor unit or to maintain the current auxiliary motor unit and main motor unit as is. That is, if the input power angle of the current auxiliary motor unit calculated through the selection unit in the selection step (S10) is greater than the reference value, the current auxiliary motor unit is automatically converted to the main motor unit and the existing main motor unit is automatically converted to the auxiliary motor unit, and the calculated current auxiliary motor unit is automatically converted to the auxiliary motor unit. If the negative input power angle is less than or equal to the reference value, the current auxiliary motor unit and main motor unit are maintained as is.

In the tandem control of a machine tool according to the present invention, the main motor switching control method is to control the first motor unit and the second motor unit through tandem control of the servo drive, where one of the first motor unit and the second motor unit is the main motor unit and the other one is the main motor unit. The motor is driven by the auxiliary motor unit, and when an unbalanced load occurs during tandem control, the first motor unit and the second motor unit automatically switch between the main motor unit and the auxiliary motor unit under the control of the servo drive, thereby performing stable speed control. This reduces manufacturing costs, improves reliability by improving stability, and can be used universally regardless of the type and capacity of the servomotor, increasing the compatibility of the main motor conversion control system and its control method in tandem control of machine tools. You can do it.

Although the detailed description of the present invention described above has been described with reference to preferred embodiments of the present invention, those skilled in the art or those skilled in the art will understand the present invention as described in the patent claims to be described later. It will be understood that the present invention can be modified and changed in various ways without departing from the spirit and technical scope. Therefore, the technical scope of the present invention should not be limited to what is described in the detailed description of the specification, but should be defined by the scope of the patent claims.

1: Main motor conversion control system
10: 1st servo drive
11: 2nd servo drive
20: first inverter
21: second inverter
30: 1st servo motor
31: 2nd servo motor
100: Numerical control unit
200: main operation unit
300: PLC
400: Servo drive
410: memory unit
420: calculation unit
430: transition unit
440: display unit
500: Power conversion unit
600: Servo motor part
610: first motor unit
620: 2nd motor unit

Claims (10)

Numerical control unit;
main operation department;
A PLC that executes control commands through communication with the numerical control unit or the main operation unit;
A servo drive that executes control commands from the PLC;
A servo motor unit including a first motor unit and a second motor unit connected in parallel to each other and driven by the servo drive; and
It includes a power conversion unit that is electrically connected to the servo motor unit and the servo drive and applies current to the servo motor unit through tandem control of the servo drive,
The first motor unit and the second motor unit drive one of the first motor unit and the second motor unit as a main motor unit and the other one as an auxiliary motor unit through tandem control of the servo drive,
When an unbalanced load occurs, the first motor unit and the second motor unit are selectively switched to the main motor unit and the auxiliary motor unit by comparing the input power angle and the reference value of the motor unit currently operating as the auxiliary motor unit under the control of the servo drive. A control system for switching from a main motor to a tandem control of a machine tool, characterized in that:
According to paragraph 1,
According to tandem control, when an unbalanced load occurs between the main motor unit and the auxiliary motor unit, the servo drive adjusts the input power angle from the motor unit currently operating as the auxiliary motor unit among the first motor unit and the second motor unit. In tandem control of a machine tool, the speed control is performed by automatically switching the current auxiliary motor unit to the main motor unit and the existing main motor unit to the auxiliary motor unit when the calculated input power angle is greater than the reference value after calculating in real time. Main motor switching control system.
According to paragraph 1,
The servo drive is,
a memory unit storing data for automatically switching the first motor unit and the second motor unit to a main motor unit and an auxiliary motor unit under control of the servo drive when an unbalanced load occurs;
a calculation unit that checks whether an unbalanced load occurs through data stored in the memory unit and calculates an input power angle of a motor unit currently operating as an auxiliary motor unit among the first motor unit and the second motor unit; and
a switching unit that determines whether to switch between the current auxiliary motor unit and the main motor unit according to tandem control according to the data stored in the memory unit and the calculation result of the calculation unit; Transition control system.
According to paragraph 3,
The memory unit,
A basic data storage unit that stores information on reference values, terminal voltage, excitation voltage, synchronous reactance, and synchronous angular velocity;
A collection data storage unit that stores data on motor speed, magnet flux, D-axis current, Q-axis current, maximum input power, maximum output power, and stator resistance; and
A main motor switching control system in tandem control of a machine tool, comprising a real-time data storage unit that stores the results of the calculation unit and the switching unit in real time.
According to paragraph 3,
The calculation unit is,
a confirmation unit that checks whether an unbalanced load occurs when the first motor unit and the second motor unit operate through tandem control, with one currently operating as a main motor unit and the other as an auxiliary motor unit;
an input power calculation unit that calculates the current input power of the auxiliary motor unit through data stored in the memory unit when an unbalanced load occurs as a result of the verification unit;
an output power calculation unit that calculates the current output power of the auxiliary motor unit using the input power calculated by the input power calculation unit and data stored in the memory unit; and
an input power angle calculation unit that calculates the current input power angle of the auxiliary motor unit according to the input power calculated by the input power calculation unit, the output power calculated by the output power calculation unit, and the data stored in the memory unit; A main motor switching control system in tandem control of a machine tool, comprising:
According to clause 5,
The switching unit,
a comparison unit that compares the current input power angle of the auxiliary motor unit calculated through the input power angle calculation unit with data stored in the memory unit; and
As a result of the comparison of the comparison unit, if the input power angle of the current auxiliary motor unit calculated through the input power angle calculation unit is greater than the reference value, the current auxiliary motor unit is automatically converted to the main motor unit and the existing main motor unit is automatically converted to the auxiliary motor unit, and the input power angle is automatically converted to the main motor unit. If the input power angle of the current auxiliary motor unit calculated through the calculation unit is less than or equal to the reference value, a selection unit that maintains the current auxiliary motor unit and the main motor unit as is; a main motor in tandem control of a machine tool, comprising a. Transition control system.
According to clause 5,
The input power angle calculator,
A main motor switching control system in tandem control of a machine tool, characterized in that the magnitude of the input power and output power of the auxiliary motor part are the same in a normal state and the calculation is performed while ignoring the resistance component.
According to paragraph 3,
The servo drive is,
A main motor switching control system in tandem control of a machine tool, further comprising a display unit that displays results of the memory unit, the calculation unit, and the switching unit.
When an unbalanced load occurs, storing data to automatically convert the first motor unit and the second motor unit into a main motor unit and an auxiliary motor unit under the control of a servo drive;
Executing control commands in a PLC through communication with a numerical control unit or main operation unit;
Executing a control command transmitted from the PLC by the servo drive;
Among the first motor unit and the second motor unit, one is primarily selected as a main motor unit and the other is primarily selected as an auxiliary motor unit, and the selected main motor unit and the auxiliary motor unit are controlled in tandem through the servo drive;
Checking whether an unbalanced load occurs when the first motor unit and the second motor unit are controlled in tandem, with one currently operating as a main motor unit and the other motor unit as an auxiliary motor unit;
As a result of confirmation, if an unbalanced load occurs, calculating the current input power of the auxiliary motor unit through pre-stored data;
Calculating the current output power of the auxiliary motor unit using the calculated input power and previously stored data;
calculating the current input power angle of the auxiliary motor unit according to the calculated input power, the calculated output power, and previously stored data;
Comparing the calculated current input power angle of the auxiliary motor unit with a pre-stored reference value; and
Tandem control of a machine tool, comprising automatically converting the current auxiliary motor unit to the main motor unit and the existing main motor unit to the auxiliary motor unit according to the comparison results, or selecting whether to maintain the current auxiliary motor unit and the main motor unit as is. Main motor switching control method.
According to clause 9,
The selection step is,
If the calculated input power angle of the current auxiliary motor unit is greater than the standard value, the current auxiliary motor unit is automatically converted to the main motor unit and the existing main motor unit is automatically converted to the auxiliary motor unit. If the calculated input power angle of the current auxiliary motor unit is less than or equal to the standard value, the existing main motor unit is automatically converted to the auxiliary motor unit. A main motor switching control method in tandem control of a machine tool, characterized in that the current auxiliary motor unit and main motor unit are maintained as is.

Images