Machining simulation device and machining simulation method

Abstract

Provided is a machining simulation device capable of obtaining a transfer function of a machine tool without requiring data collection and professional knowledge. A machining simulation device includes: a transmission characteristic generation unit that generates transmission characteristics of a machine tool; and a simulation execution unit that simulates the behavior of the machine tool using the transmission characteristics, the transmission characteristic generation unit including: a control information acquisition unit that acquires the motor information and a control parameter of a motor control system of the machine tool; a motor characteristic calculation unit that calculates motor characteristics on the basis of the motor information; a control characteristic calculation unit that calculates a control characteristic of the motor control system on the basis of the control parameter; and a transmission characteristic calculation unit that calculates a transmission characteristic that satisfies a predetermined requirement on the basis of the motor characteristic and the control characteristic.

Description

Technical Field

[0001] The present disclosure relates to a machining simulation device and a machining simulation method, and more particularly to a machining simulation device and a machining simulation method for simulating the behavior of a machine tool using a transfer function representing the transfer characteristics of the machine tool. Background Art

[0002] Patent Documents 1 to 4 describe techniques for simulating the behavior of a machine tool using a transfer function representing the transfer characteristics of the machine tool.

[0003] Patent Document 1 describes a numerical control method that enables machining to be performed in a short time without causing damage to the machined surface even if an error is included in a command path.

[0004] Specifically, Patent Document 1 describes the following: A numerical control method predicts the trajectory of a machining tool when the speed of a machine tool is controlled by the command path and the command feed speed indicated by the machining program based on the transfer characteristics from the command position to the machining position, and obtains the allowable feed speed based on the characteristic quantity representing the time variation of the position of the machining tool on the predicted trajectory and its allowable value. The characteristic quantity uses the acceleration of the machining tool on the predicted trajectory or the normal component of the acceleration.

[0005] Patent Document 2 describes a machining simulation device that prevents the occurrence of chattering vibrations due to resonance and achieves improvement in surface accuracy and the like.

[0006] Specifically, Patent Document 2 states that: a machining simulation device performs machining simulation on graphic data before machining, and a machining simulation unit simulates the frequency of forced vibration caused by intermittent cutting and / or the frequency of load variation according to machining information, and a numerical control instruction generation unit generates a numerical control instruction according to the frequency obtained thereby. It is also stated that, through the machining simulation device, the spindle rotation speed can be reflected in actual machining or machining program generation under conditions suitable for actual machining, so that the frequency of forced vibration caused by intermittent cutting and / or the frequency of load variation or their integer multiple harmonic frequencies will not be close to the natural vibration frequency of the machine, tool, fixture or workpiece, etc., and the generation of chatter caused by resonance can be prevented.

[0007] Patent Document 3 describes a processing method for obtaining correction data in a short time.

[0008] Specifically, patent document 3 describes a processing method for processing a non-circular workpiece, wherein, in the first step, the contour data of the non-circular workpiece is divided into data of the workpiece spindle and the tool feed axis, each data is Fourier transformed, and the gain and phase at each frequency are calculated; in the second step, the gain and phase of each frequency are calculated according to the transfer function of the contour shape processing spindle device and the transfer function of the tool feed axis device; in the third step, for the workpiece spindle and the tool feed axis, the gain and phase of each frequency obtained from the second step are added to the gain and phase of each frequency obtained from the first step; in the fourth step, an inverse Fourier transform is performed on the frequency data of the workpiece spindle and the tool feed axis of the non-circular workpiece obtained in the third step; in the fifth step, processing data, i.e., correction data, is prepared for the workpiece spindle and the tool feed axis of the non-circular workpiece obtained in the fourth step; and the non-circular workpiece is processed based on the correction data.

[0009] Patent Document 4 describes a machining simulation device for a machine tool that can perform machining simulation with high accuracy while suppressing an increase in time.

[0010] Specifically, patent document 4 describes a processing simulation device that performs processing simulation of a machine tool that uses a tool to process a processing object based on a processing program, wherein the processing simulation device comprises: a mechanical simulation unit that simulates the movement of the machine tool when the machine tool performs the action based on the processing program based on position instructions and the transfer characteristics of the machine tool, thereby estimating the position of the tool; and a processing simulation unit that performs processing simulation of the processing object based on information about the tool and the estimated position of the tool.

[0011] Prior art literature

[0012] Patent Literature

[0013] Patent Document 1: Japanese Patent Application Publication No. 2001-051708

[0014] Patent Document 2: International Publication No. 2002 / 003155

[0015] Patent Document 3: Japanese Patent Application Publication No. 2002-278609

[0016] Patent Document 4: Japanese Patent Application Publication No. 2019-152936 Summary of the invention

[0017] Problems to be solved by the invention

[0018] When obtaining the transfer function of a machine tool in order to perform machining simulation, data collection work accompanying a test run of the machine tool and expertise for analyzing the collected data and calculating the transfer characteristics are required.

[0019] Therefore, it is desired to obtain the transfer function of a machine tool without requiring data collection accompanying a test run of the machine tool and specialized knowledge for calculating the transfer characteristic.

[0020] Means for solving problems

[0021] A first representative aspect of the present disclosure is a processing simulation device including:

[0022] a transfer characteristic generating unit that generates a transfer characteristic of the machine tool;

[0023] a simulation execution unit that uses the transfer characteristic to simulate the behavior of the machine tool,

[0024] The transfer characteristic generating unit comprises:

[0025] a control information acquisition unit that acquires control information including motor information of the machine tool and control parameters of a motor control system of the machine tool from a storage unit;

[0026] a motor characteristic calculation unit that calculates motor characteristics based on the motor information;

[0027] a control characteristic calculation section that calculates a control characteristic of the motor control system based on the control parameter; and

[0028] a transfer characteristic calculation unit that calculates the transfer characteristic satisfying a predetermined requirement based on the motor characteristic and the control characteristic,

[0029] The predetermined requirement includes at least one of a response frequency of position control, a response frequency of speed control, a natural vibration frequency of the machine tool, and a resonance frequency between a driving part and a driven part in the machine tool.

[0030] A second representative aspect of the present disclosure is a machining simulation method, wherein a computer executes the following processing:

[0031] A process for calculating motor characteristics based on motor information of a machine tool;

[0032] a process of calculating control characteristics of the motor control system based on control parameters of the motor control system of the machine tool;

[0033] A process of calculating a transfer characteristic satisfying a predetermined requirement based on the motor characteristic and the control characteristic; and

[0034] a process of using the transfer characteristics to simulate the behavior of the machine tool,

[0035] The predetermined requirement includes at least one of a response frequency of position control, a response frequency of speed control, a natural vibration frequency of the machine tool, and a resonance frequency between a driving part and a driven part in the machine tool. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Figure 1 It is a configuration diagram showing a configuration example of a machining simulation system for a machine tool according to one embodiment of the present invention.

[0037] Figure 2 This diagram represents the driving and driven parts of a machine tool using a rigid body model.

[0038] Figure 3 This diagram represents the driving part and driven part of a machine tool using a dual inertia system model.

[0039] Figure 4 This is a block diagram showing the configuration of a position control loop when a motor control system, a driving unit, and a driven unit constitute a position control loop.

[0040] Figure 5 This is a block diagram showing a simplified structure of a position control loop.

[0041] Figure 6 This is a block diagram showing the configuration of a speed control loop when a motor control system, a driving unit, and a driven unit constitute a speed control loop.

[0042] Figure 7 It is a characteristic diagram schematically showing the frequency response gain of the transfer function.

[0043] Figure 8 This is a characteristic diagram showing an example of the frequency response gain of the speed PI control.

[0044] Fig. 9 This is a characteristic diagram showing an example of the frequency response gain of the speed P control.

[0045] Fig.10 This is a diagram showing an example of a user interface displayed on a display screen of a display device of a personal computer.

[0046] Fig.11 This is a flowchart showing the operation of the machining simulation device. DETAILED DESCRIPTION

[0047] Hereinafter, embodiments of the present disclosure will be described in detail using the drawings.

[0048] Figure 1 It is a structural diagram showing a structural example of a machining simulation system for a machine tool according to one embodiment of the present invention.

[0049] like Figure 1 As shown, a machining simulation system 10 for a machine tool includes a control device 100 for a machine tool and a machining simulation device 200 .

[0050] The control device 100 of the machine tool controls the movement of the feed axis, the rotation of the main shaft, etc. of the machine tool according to the machining program. The control device 100 has a motor and a driven part that serve as the driving part of the machine tool, and a motor control system that controls the motor. The control device 100 stores the motor information of the machine tool and the control parameters of the motor control system in the storage unit 101. The motor information and control parameters will be described later. The motor information and control parameters of the machine tool may also be stored in a storage unit that is separately provided from the control device 100. The storage unit may also be provided in the machining simulation device 200. In the case where the storage unit is separately provided from the control device 100, the machining simulation system 10 may not include the control device 100 of the machine tool.

[0051] The machining simulation device 200 includes a transfer characteristic generating unit 210 and a simulation executing unit 220. The transfer characteristic generating unit 210 calculates the transfer function of the machine tool using the motor information and control parameters acquired from the storage unit 101 of the machine tool control device 100. The simulation executing unit 220 uses the calculated transfer function to simulate the control of the machine tool control device 100 based on the machining program, the behavior of the motor as the driving unit and the driven unit, and the feedback control of the control device 100 based on the position information of the driving unit and the driven unit (for example, the feedback control described later). Figure 4 The position information of each axis is output as a simulation result.

[0052] The transfer characteristic generation unit 210 includes a control information acquisition unit 211 , a motor characteristic calculation unit 212 , a control characteristic calculation unit 213 , and a transfer characteristic calculation unit 214 .

[0053] Hereinafter, each configuration of the transfer characteristic generation unit 210 will be described.

[0054] (Control Information Acquisition Unit 211)

[0055] The control information acquisition unit 211 acquires control information including motor information and control parameters from the storage unit 101 of the control device 100 of the machine tool. The motor information is, for example, based on at least one of the motor inertia (also called motor inertia), inertia ratio, and spring constant of the motor. The inertia ratio represents load inertia / motor inertia. Load inertia is also called load inertia. Motor inertia sometimes also includes the inertia of the reducer and the ball screw. The control parameter is, for example, the position control proportional gain K of the position control unit included in the motor control system of the control device 100. P , and speed loop gain K V , speed control integral gain K of speed control unit 1 And the speed control proportional gain K of the speed control unit 2 at least one of .

[0056] The storage unit 101 may store the motor inertia as part of the specification or motor characteristic database. In this case, the control information acquisition unit 211 acquires information that can identify the motor, such as the motor model, from the storage unit 101 and acquires the motor inertia by referring to the specification or motor characteristic database.

[0057] (Motor Characteristics Calculation Unit 212)

[0058] The motor characteristic calculation unit 212 calculates the motor characteristics based on the motor information.

[0059] If Figure 2 The rigid body system model shown in FIG. 1 represents the mechanical model of the motor and the driven part of the machine tool. If the motor information is the motor inertia J M , inertia ratio R, motor characteristics M 1 It is represented by the transfer function of Mathematical Formula 1 (hereinafter referred to as Mathematical Formula 1). s is a variable of Laplace transformation.

[0060] [Mathematical formula 1]

[0061]

[0062] If Figure 3 The dual inertia system model shown in FIG. 1 is used to represent the mechanical model of the motor and the driven part of the machine tool. When the motor information is the motor inertia J M , natural vibration frequency ω O , resonance frequency ω P When the motor characteristic M 2 It is represented by the transfer function of Mathematical Formula 2 (hereinafter referred to as Mathematical Formula 2).

[0063] [Mathematical formula 2]

[0064]

[0065] The natural vibration frequency ω in equation 2 O , resonance frequency ω P Use motor inertia J M , inertia ratio R, and spring constant K of the spring element between motor inertia and load inertia S , calculated by Formula 3 (the following Formula 3).

[0066] [Mathematical formula 3]

[0067]

[0068] The natural vibration frequency ω of the dual inertia system model OIt is the natural frequency of the free vibration of the driven part when the driving part is fixed, sometimes called the anti-resonance frequency. The resonant frequency ω of the dual inertial system model P This is the frequency at which the driving part and the driven part vibrate in opposite phases.

[0069] Regarding the transfer function combining the motor inertia and the load inertia using spring elements, for example, it is recorded in "Study on low-frequency vibration suppression control based on a dual-inertia system model for the feed axis of NC machine tools", Heisuke Iwashita et al., Journal of the Japan Society for Precision Engineering, Vol. 82, No. 8, 2016.

[0070] (Control Characteristics Calculation Unit 213)

[0071] The control characteristic calculation unit 213 calculates the control characteristic of the motor control system based on the control parameter.

[0072] When the motor control system included in the control device 100, the driving unit, and the driven unit form a position control loop, the position control loop is composed of Figure 4 The block diagram of Figure 4 As shown in FIG. 1 , the position control loop can be represented by a position control unit 111, a speed control unit 112, a mechanical model unit 113 composed of a driving unit and a driven unit, and an integrator 114. Figure 4 As shown in the figure, the position control loop is usually composed of a double loop with a speed control loop inside. Figure 4 In the figure, y' represents the position command, y represents the actual position, r represents the speed command, u represents the operation amount, and w represents the actual speed. The operation amount u is, for example, a torque command, but in a servo motor, the torque constant K T , torque = K T × current holds, so the manipulated variable u may also be set to current.

[0073] The response frequency of the position control loop has to be lower than the response frequency of the speed control loop located inside, so for simplicity, the position control loop is Figure 4 In the structure of the block diagram shown in the figure, the closed-loop transfer function from the speed command r to the speed performance w is regarded as 1, which can be Figure 5 The structure of the block diagram is shown.

[0074] In the position control loop is Figure 5 In the case of the structure of the block diagram shown in FIG. 1 , the position control loop is composed of the position control unit 111 and the integrator 114, and the motor control system corresponds to the position control unit 111. The control characteristic C of the position control unit 111 of the motor control system is P Using C P =K P To express, the control parameter is the position control proportional gain K P .

[0075] When the motor control system included in the control device 100, the driving unit, and the driven unit form a speed control loop, the speed control loop is as follows: Figure 6 The speed control loop can be represented by a speed control unit 112 and a mechanical model unit 113 composed of a driving unit and a driven unit. The speed control unit 112 is equivalent to a motor control system.

[0076] In the case of speed PI control, the control characteristic C of the speed control unit 112 of the motor control system becomes V It is represented by Mathematical Formula 4 (hereinafter referred to as Mathematical Formula 4). In Mathematical Formula 4, K V is the speed loop gain, K 1 is the speed control integral gain, K 2 is the speed control proportional gain. The control parameter is the speed loop gain K V , speed control integral gain K 1 And speed control proportional gain K 2 .

[0077] [Formula 4]

[0078]

[0079] In the case of speed P control, the control characteristic C of the speed control unit V By setting K in equation 4 1 =0, K 2 = 1 and find out, it becomes C V =K V The control parameter is the speed loop gain K V .

[0080] (Transfer characteristic calculation unit 214)

[0081] The transfer characteristic calculation unit 214 changes at least one of the motor characteristic calculated by the motor characteristic calculation unit 212 and the control characteristic calculated by the control characteristic calculation unit 213 to calculate the transfer characteristic of the machine tool so as to satisfy a predetermined requirement. The predetermined requirement is at least one of the response frequency of the position control, the response frequency of the speed control, the natural vibration frequency of the machine tool, and the resonance frequency of the driving part and the driven part in the machine tool. The predetermined requirement will be described later. The value of the predetermined requirement may be given by the user, or may be obtained by the transfer characteristic calculation unit 214 from the storage unit 101 of the control device 100, a storage unit provided outside the control device 100, or a storage unit provided in the processing simulation device.

[0082] First, the transfer characteristics of the machine tool will be described.

[0083] The closed loop transfer function GC Using the open loop transfer function G O , use G C =G O / (1+G O )express.

[0084] The transfer characteristic calculation unit 214 obtains the closed-loop transfer function G of the position control loop as follows: PC (s), closed-loop transfer function G of the speed control loop VC (s).

[0085] because Figure 5 The open-loop transfer function G of the position control loop is shown as PO (s) is G PO (s) = K P / s, so the closed-loop transfer function of the position control loop is G PC (s) is expressed by Formula 5 (hereinafter referred to as Formula 5).

[0086] [Formula 5]

[0087]

[0088] The closed-loop transfer function G of the speed control loop VC (s), in the case of speed PI control, the open-loop transfer function G VO (s) is expressed by Formula 6 (hereinafter referred to as Formula 6), and is therefore expressed by Formula 7 (hereinafter referred to as Formula 7). In Formulas 6 and 7, M represents the motor characteristics, and when the mechanical model is represented by a rigid body system model, M=M 1 When the mechanical model is represented by a dual inertial system model, M = M 2 .

[0089] [Mathematical formula 6]

[0090]

[0091] [Formula 7]

[0092]

[0093] The closed-loop transfer function of the speed control loop is G VC (s) In the case of speed P control, by setting K in equation 7 1 =0, K 2 =1 and is expressed by Formula 8 (hereinafter referred to as Formula 8).

[0094] [Mathematical formula 8]

[0095]

[0096] Next, predetermined requirements will be described.

[0097] (When the predetermined requirement is the response frequency of the position control)

[0098] If the transfer function is a rational function of s, then when the command a is a sine wave with a frequency of ω, the control variable b also becomes a sine wave with a frequency of ω. At this time, the amplitude ratio of the command a and the control variable b is called the frequency response gain at the frequency of ω. The closed-loop transfer function G C The frequency response gain of (s) can be calculated by replacing s with jω using Formula 9 (hereinafter referred to as Formula 9). The unit is decibel (dB).

[0099] [Mathematical formula 9]

[0100] 20log|G C (jω)|

[0101] Generally, the frequency response gain of the closed-loop transfer function is near 0 dB when the frequency response gain of the open-loop transfer function is 0 dB or more. When the frequency response gain of the closed-loop transfer function is near 0 dB (amplitude ratio 1), it means that the controlled variable b follows the command a.

[0102] Therefore, the frequency response gain of the closed-loop transfer function intersects with or becomes maximum at about 0dB-3dB (amplitude ratio 1 / √2) is called the control response frequency.

[0103] In addition, the frequency at which the frequency response gain of the open-loop transfer function intersects with 0 dB is called the control response frequency.

[0104] If the transfer function G of mathematical formula 5 is PC When s in (s) is replaced by jω, equation 10 (hereinafter referred to as equation 10) is obtained, ω=K where 20log|G(jω)|=-3dB is obtained. P It becomes the response frequency of position control.

[0105] [Formula 10]

[0106]

[0107] (When the predetermined requirement is the response frequency of speed control)

[0108] The open-loop transfer function of the speed control loop when the control characteristic C is speed P control and the motor characteristic M is a dual inertia system model is expressed by Formula 11 (hereinafter referred to as Formula 11).

[0109] [Mathematical formula 11]

[0110]

[0111] The frequency response gain of the transfer function of Equation 11 is given by Figure 7 The gain line diagram is shown schematically. Figure 7 In the figure, the horizontal axis is the logarithmic scale of frequency.

[0112] The position where the frequency response gain intersects with 0 dB is the response frequency, the position where the frequency response gain takes a minimum value is the natural vibration frequency, and the position where the frequency response gain takes a maximum value is the resonance frequency.

[0113] like Figure 7 As shown, the frequency value is usually resonant frequency> natural vibration frequency> speed control response frequency. This relationship is also the same in the case of speed PI control. When the frequency ω is below the speed control response frequency, the resonant frequency ω P > Natural vibration frequency ω O >Frequencyω(ω P >ω O >ω), becomes ω P 2 >ω O 2 >ω 2 , so we can ignore s in equation 2 2 If we ignore s 2 , then Mathematical formula 2 is equal to Mathematical formula 1. That is, when the response frequency of the speed control is considered, Mathematical formula 1 representing the rigid body system model can be used as the motor characteristic M.

[0114] <In the case of speed PI control>

[0115] As the control characteristic C, when the speed PI control is considered and a rigid body system model is used as the motor characteristic M, the equation 7 is as shown in the equation 12 (hereinafter referred to as the equation 12).

[0116] [Mathematical formula 12]

[0117]

[0118] When s in Formula 12 is replaced by jω, Formula 12 becomes as shown in Formula 13 (hereinafter referred to as Formula 13).

[0119] [Mathematical formula 13]

[0120]

[0121] Using Equation 13, the frequency response gain is expressed as in Equation 14 (hereinafter referred to as Equation 14).

[0122] [Mathematical formula 14]

[0123]

[0124] In equation 14, the frequency response gain is 0 dB or more until the value of equation 15 (hereinafter equation 15) at which the absolute value of the denominator is equal to the absolute value of the numerator. Therefore, the value ω of equation 15 is used as the response frequency of the speed PI control.

[0125] [Mathematical formula 15]

[0126]

[0127] Figure 8 This is a characteristic diagram showing an example of the frequency response gain of the speed PI control.

[0128] <Speed ​​P Control>

[0129] Considering the case of speed P control as the control characteristic C, when using the rigid body system model as the motor characteristic M, in mathematical formula 14, let K 1 =0, K 2 =1, the frequency response gain is as shown in Formula 16 (hereinafter referred to as Formula 16).

[0130] [Formula 16]

[0131]

[0132] In equation 16, the value ω of equation 17 (hereinafter referred to as equation 17) of 20log|G(jω)|=-3dB is used as the response frequency of the speed P control.

[0133] [Mathematical formula 17]

[0134]

[0135] Fig. 9 This is a characteristic diagram showing an example of the frequency response gain of the speed P control.

[0136] (When the predetermined requirement is the natural vibration frequency or resonance frequency of the machine tool)

[0137] As mentioned above, if you use Figure 3 The dual inertia system model shown in FIG. 1 represents the motor as the driving part of the machine tool and the driven part. When the motor information is the motor inertia J M , natural vibration frequency ω O , resonance frequency ω P When the motor characteristic M 2 It is expressed by equation 2. The natural vibration frequency ω in equation 2 is O , resonance frequency ω P Use the motor inertia J M, inertia ratio R, spring constant K of the spring element between motor inertia and load inertia S , expressed by Mathematical Formula 3. These natural vibration frequencies ω O , resonance frequency ω P It becomes the natural vibration frequency and resonant frequency of the machine tool.

[0138] A method in which the transfer characteristic calculation unit 214 calculates the transfer characteristic of a machine tool that satisfies predetermined requirements will be described below.

[0139] The transfer characteristic generating unit 210 included in the machining simulation device 200 has Fig.10 The user interface is shown as application software for a personal computer.

[0140] Fig.10 This is a diagram showing an example of a user interface displayed on a display screen of a display device of a personal computer.

[0141] like Fig.10 As shown, the value read from the control information acquired by the control information acquisition unit 211 is displayed on the display screen, for example, the position control proportional gain K P , speed loop gain K V , speed control integral gain K 1 , speed control proportional gain K 2 Other control parameters, and motor inertia J M , inertia ratio R, spring constant K S Specifically, Fig.10 As shown, the position control proportional gain K on the display screen P Displayed as 30, speed loop gain K V Displayed as 1, speed control integral gain K 1 Displayed as 1089, speed control proportional gain K 2 Displayed as 10.164, motor inertia J M Displayed as 0.022[kgm 2 ], the inertia ratio R is shown as 1.2, and the spring constant K S The displayed value is 6878 [Nm]. These control parameters and motor information are changed based on predetermined requirements input by the user.

[0142] On the left side of the screen, an area is displayed for selecting the axis for which a model is to be generated from among multiple axes of the machine tool.

[0143] The user sets the predetermined requirements through an input form (not shown). Fig.10 The “speed control response frequency: target 50 Hz” which is the setting result in the input table is displayed in the graph, and the dotted line in the graph represents 50 Hz.

[0144] By pressing Fig.10 The transfer characteristic calculation unit 214 changes the control characteristic or the motor characteristic according to a predetermined condition and supplies the generated transfer characteristic to the simulation execution unit 220. The details of the operation of changing the control characteristic or the motor characteristic according to a predetermined condition will be described later.

[0145] The frequency response of the open-loop transfer function obtained from the result read from the control information is displayed on the display screen. When the user presses the reflection button, the transfer characteristic calculation unit 214 changes the control characteristic or the motor characteristic according to the predetermined requirements, and when the transfer function is generated, the frequency response is rewritten according to the generated transfer characteristic. It is also possible to overlay the frequency response based on the generated transfer characteristic without rewriting the frequency response. In addition, the frequency response can be based on the transfer function G taking feedback into consideration. C (s).

[0146] The timing at which the transfer characteristic calculation unit 214 changes the control characteristic or the motor characteristic or changes the display of the frequency response may not be when the reflection button is pressed, but may be when the user changes a predetermined element through an input form, for example.

[0147] Fig.10 The numerical values ​​shown in the figure may be rounded off to an appropriate number of decimal places, but the number of decimal places has no particular meaning and is not particularly limited.

[0148] In addition, Fig.10 It is assumed that the motor is a rotary motor and the unit of motor inertia is inertia [kgm 2 ], but when a linear motor is used, the unit of inertia can also be set to mass [kg]. The spring constant is also set to [Nm] assuming a torsion spring, but when a telescopic spring is used, it can also be set to [N / m].

[0149] The natural vibration frequency ω shown in equation 3 O and the resonant frequency ω P , the frequency ω shown in equation 10, the frequency ω shown in equation 15, and the frequency ω shown in equation 16 are angular frequencies [rad / s]. Fig.10 The units of frequencies exemplified for screen display and predetermined requirements are Hz, but these units may also be rad / s.

[0150] An operation example in which the transfer characteristic calculation unit 214 changes the control characteristic or the motor characteristic according to the predetermined requirements in order to calculate the transfer characteristic of the machine tool satisfying the predetermined requirements will be described below.

[0151] (1) Change the position control proportional gain K PExample of satisfying the predetermined requirement of "position control response frequency"

[0152] When the user specifies 10 Hz as the response frequency of the position control, if the frequency 10 Hz is expressed as an angular frequency, it becomes 10×2π(rad / s)=62.832(rad / s). As explained using mathematical formula 10, since the position control proportional gain K P Equal to the response frequency of position control, so the position control proportional gain K P Set to K P =10×2π=62.832.

[0153] Become the control characteristic C P Position control proportional gain K P from Fig.10 The value 30 shown is changed to 62.832 so as to satisfy the "response frequency of position control" which is a predetermined requirement.

[0154] (2) Change the speed loop gain K V Example of satisfying the predetermined requirement "speed control response frequency" (in the case of speed PI control)

[0155] The left side of Formula 15 is changed to fc [Hz] to obtain Formula 18 (hereinafter referred to as Formula 18).

[0156] [Mathematical formula 18]

[0157]

[0158] In equation 18, the motor inertia J M No change. Generally, in PI control, the speed control integral gain K is adjusted in a balanced manner. 1 and speed control proportional gain K 2 , but the speed control integral gain K is not changed here 1 About changing the remaining speed loop gain K V and inertia ratio R, the user can choose Fig.10 The detailed setting items not shown in the figure can be changed by only changing one of them. Alternatively, one of them can be changed preferentially within the allowable range according to the detailed setting items, and the other can be changed when the predetermined requirements cannot be met within the allowable range.

[0159] In this example, the following describes how to change only the speed loop gain K V The speed control response frequency of 50 Hz is an example to meet the predetermined requirements. V Solve equation 18 and calculate the speed loop gain K through equation 19 (hereinafter referred to as equation 19): V .

[0160] [Mathematical formula 19]

[0161]

[0162] In this way, the control characteristic C V The speed loop gain K V Changed from 1 to 2.191, changed control characteristic C V , in order to satisfy the "speed control response frequency" which is a predetermined requirement.

[0163] (3) Change the speed loop gain K V Example of satisfying the predetermined requirement "speed control response frequency" (in the case of speed P control)

[0164] The left side of Formula 17 is changed to fc [Hz] to obtain Formula 20 (hereinafter referred to as Formula 20).

[0165] [Mathematical formula 20]

[0166]

[0167] In equation 20, the motor inertia J M In this example, the case where the "speed control response frequency" of 50 Hz, which is a predetermined requirement, is satisfied by changing the inertia ratio R is first studied. Formula 20 is solved for the inertia ratio R, and the inertia ratio R is obtained by Formula 21 (hereinafter referred to as Formula 21).

[0168] [Mathematical formula 21]

[0169]

[0170] The inertia ratio R can be 0 when there is no load inertia, but it cannot be negative. Therefore, if R = 0, for K V Solve equation 20, and the speed loop gain K V This becomes Formula 22 (hereinafter referred to as Formula 22).

[0171] [Mathematical formula 22]

[0172] K V =2πf C J M =2π×50×0.022=6.912

[0173] In this way, in order to satisfy the predetermined requirement of "speed control response frequency", the motor characteristic M 1 The inertia ratio R is changed from 1.2 to 0, and the control characteristic C V The speed loop gain K VChange from 1 to 6.912, thus changing the motor characteristic M 1 And control characteristics C V .

[0174] (4) Change the spring constant K S In order to satisfy the predetermined requirement "the natural frequency of the machine tool", the spring constant K is S Solve the natural vibration frequency ω shown in equation 3 O , and obtain Mathematical Formula 23 (the following Mathematical Formula 23).

[0175] [Mathematical formula 23]

[0176] K S =RJ M ω O 2

[0177] When the predetermined requirement is a natural frequency of 45 Hz, the spring constant K shown in equation 24 (hereinafter equation 24) is obtained by equation 23: S .

[0178] [Mathematical formula 24]

[0179] K S =RJ M ω O 2 =1.2×0.022×(2×π×45) 2 =2111[Nm]

[0180] In this way, the spring constant K of the motor characteristic is S from Fig.10 The 6878 [Nm] shown is changed to 2111 [Nm], and the motor characteristic M is changed 2 , in order to satisfy the "natural vibration frequency of the machine tool" which is a predetermined requirement.

[0181] (5) Change the spring constant K S Example of satisfying the predetermined requirement "resonance frequency of the driving part and the driven part in the machine tool"

[0182] For spring constant K S Solve the resonant frequency ω shown in equation 3 P , and obtain mathematical formula 25 (the following mathematical formula 25).

[0183] [Mathematical formula 25]

[0184]

[0185] When the predetermined requirement is a resonance frequency of 80 Hz, the spring constant K shown in equation 26 (hereinafter equation 26) is obtained by equation 25: S .

[0186] [Mathematical formula 26]

[0187]

[0188] In this way, the spring constant K that becomes the motor characteristic S from Fig.10 The 6878 [Nm] shown is changed to 3032 [Nm], and the motor characteristic M is changed 2 , so as to satisfy the predetermined requirement of "resonance frequency of the machine tool".

[0189] In the above examples (4) and (5), the spring constant K is changed. S Although the example of is described, the inertia ratio R may also be changed. S and inertia ratio R, the user can choose Fig.10 The detailed setting items not shown in the figure can be changed by only changing one of them. Alternatively, one of them can be changed preferentially within the allowable range according to the detailed setting items, and the other can be changed when the predetermined requirements cannot be met within the allowable range.

[0190] The transfer characteristic calculation unit 214 can change at least one of the motor inertia, inertia ratio, spring constant, position control proportional gain, speed loop gain, speed control integral gain, and speed control proportional gain so that the transfer characteristic satisfies the predetermined requirements. When the rigid body system model taking into account the load inertia is not used as the motor characteristic (R=0), the transfer characteristic calculation unit 214 can use a rigid body system model obtained by adding the load inertia to the motor inertia so that the transfer characteristic satisfies the predetermined requirements. In addition, when the rigid body system model is used as the motor characteristic, the transfer characteristic calculation unit 214 can use a dual inertia system model combining the motor inertia and the load inertia through a spring element so that the transfer characteristic satisfies the predetermined requirements.

[0191] In the above-described embodiment, more factors are considered in the control characteristics and the motor characteristics, and a more accurate simulation result can be expected. For example, in academic literature, a damper (damping) is considered when the dual inertial system model is first derived.

[0192] However, even if the simulation execution unit takes the damper or nonlinearity into consideration, the damper or nonlinearity can be ignored in the calculation of the control characteristic or motor characteristic changed by the transfer characteristic calculation unit. This is because the damper and nonlinearity are less sensitive to frequency characteristics such as the response frequency, natural frequency, and resonance frequency than the control gain, inertia ratio, and spring constant.

[0193] In the above, each structure of the processing simulation device 200 has been described.

[0194] In the following description, an example in which the machining simulation method is executed using the machining simulation device 200 is described, but the machining simulation method may also be executed in a device other than the machining simulation device 200 .

[0195] Fig.11 This is a flowchart showing the operation of the machining simulation device.

[0196] In step S1, the control information acquisition unit 211 acquires control information including motor information and control parameters. The motor information is, for example, based on at least one of the motor inertia, inertia ratio, and spring constant of the motor. The control parameter is, for example, a position control proportional gain K of the position control unit included in the motor control system of the control device 100. P , speed loop gain K V , speed control integral gain K of speed control unit 1 , and the speed control proportional gain K of the speed control unit 2 at least one of .

[0197] In step S2 , the motor characteristic calculation unit 212 calculates the motor characteristics based on the motor information.

[0198] In step S3, the control characteristic calculation unit 213 calculates the control characteristic of the motor control system based on the control parameter. Step S3 may be performed before step S2 or in parallel with step S2.

[0199] In step S4 , the transfer characteristic calculation unit 214 determines whether a predetermined requirement has been input, and if so, the process proceeds to step S5 , and if not, the process proceeds to step S6 .

[0200] In step S5 , the transfer characteristic calculation unit 214 changes at least one of the motor characteristic calculated by the motor characteristic calculation unit 212 and the control characteristic calculated by the control characteristic calculation unit 213 so as to satisfy the input predetermined requirement.

[0201] In step S6, when at least one of the motor characteristic and the control characteristic is changed in step S5, the transfer characteristic calculation unit 214 calculates the transfer characteristic of the tool according to at least one of the changed motor characteristic and the control characteristic. When the predetermined requirement is not input in step S4, the transfer characteristic calculation unit 214 calculates the transfer characteristic of the tool according to at least one of the motor characteristic calculated by the motor characteristic calculation unit 212 and the control characteristic calculated by the control characteristic calculation unit 213.

[0202] In step S7, the simulation execution unit 220 uses the calculated transfer function to simulate the control of the control device 100 of the machine tool based on the machining program, the behavior of the motor as the driving part and the driven part, and the feedback control of the control device 100 based on the position information of the driving part and the driven part, and outputs the position information of each axis as a simulation result.

[0203] The components included in the machining simulation device of the embodiment described above can be implemented by hardware, software, or a combination thereof. Here, implementation by software means implementation by a computer reading and executing a program.

[0204] In order to realize the structural parts included in the machining simulation device through software or a combination thereof, the machining simulation device has a processor such as a CPU (Central Processing Unit). The processor functions as an execution unit. The machining simulation device may also have multiple processors that operate in parallel. In addition, the machining simulation device also has an auxiliary storage device such as a HDD (Hard Disk Drive) that stores various programs such as application software or OS (Operating System), and a hard disk drive for storing the programs executed by the processor. Figure 1 , Figure 6 A main storage device such as a RAM (Random Access Memory) stores programs required for the functions and operations of the machining simulation device described above and data temporarily required for the programs. The machining simulation device may include a plurality of main storage devices.

[0205] Then, in the machining simulation device, the processor reads the application software or OS from the auxiliary storage device, expands the read application software or OS in the main storage device, and performs calculation processing based on the application software or OS. In addition, based on the calculation result, various hardwares of the machining simulation device are controlled. Thus, the functional blocks of this embodiment are realized.

[0206] The structural parts included in the processing simulation device can be realized by hardware including electronic circuits, etc. In the case where the processing simulation device is composed of hardware, for example, a part or all of the functions of each structural part included in the processing simulation device can be composed of an integrated circuit (IC) such as ASIC (Application Specific Integrated Circuit), gate array, FPGA (Field Programmable Gate Array), CPLD (Complex Programmable Logic Device), etc.

[0207] The program can be stored and provided to the computer using various types of non-transitory computer readable media. Non-transitory computer readable media include various types of tangible storage media. Examples of non-transitory computer readable media include magnetic recording media (e.g., hard disk drives), magneto-optical recording media (e.g., magneto-optical disks), CD-ROMs (read-only memories), CD-Rs, CD-R / Ws, and semiconductor memories (e.g., mask ROMs, PROMs (programmable ROMs), EPROMs (erasable PROMs), flash ROMs, and RAMs (random access memories)). In addition, the program can also be provided to the computer via various types of transient computer readable media (transitory computer readable medium).

[0208] The machining simulation device and machining simulation method of the embodiment described above have the effect of being able to obtain the transfer function of the machine tool without requiring data collection accompanying the test run of the machine tool and specialized knowledge for calculating the transfer characteristic.

[0209] The present disclosure is described above, but the present disclosure is not limited to the above-mentioned embodiments and modifications. These embodiments and modifications can be variously added, replaced, changed, partially deleted, etc. without departing from the scope of the main purpose of the present disclosure, or without departing from the scope of the main purpose of the present disclosure derived from the contents recorded in the scope of the patent protection requested and its equivalents.

[0210] In addition, these embodiments and modified examples can also be implemented in combination. For example, in the above-mentioned embodiment, the order of each operation and the order of each process are shown as an example, and are not limited to this.

[0211] The following supplementary notes are further disclosed with respect to the above-mentioned embodiment.

[0212] (Note 1)

[0213] A processing simulation device 200, comprising:

[0214] a transfer characteristic generating unit 210 for generating a transfer characteristic of a machine tool;

[0215] a simulation execution unit 220 that uses the transfer characteristic to simulate the behavior of the machine tool,

[0216] The transfer characteristic generating unit comprises:

[0217] a control information acquisition unit 211 that acquires control information including motor information of the machine tool and control parameters of the motor control system of the machine tool from a storage unit;

[0218] a motor characteristic calculation unit 212 for calculating motor characteristics based on the motor information;

[0219] a control characteristic calculation unit 213 for calculating the control characteristic of the motor control system based on the control parameter;

[0220] a transfer characteristic calculation unit 214 for calculating the transfer characteristic satisfying predetermined requirements based on the motor characteristic and the control characteristic,

[0221] The predetermined requirement includes at least one of a response frequency of position control, a response frequency of speed control, a natural vibration frequency of the machine tool, and a resonance frequency between a driving part and a driven part in the machine tool.

[0222] (Note 2)

[0223] The processing simulation device according to Supplement 1, wherein:

[0224] The motor information includes at least one of the motor inertia, inertia ratio and spring constant of the motor,

[0225] The control parameter includes at least one of a position control proportional gain, a speed loop gain, a speed control integral gain, and a speed control proportional gain.

[0226] (Note 3)

[0227] The processing simulation device according to Supplement 2, wherein:

[0228] The motor characteristic calculation unit 212 calculates the motor characteristic using a rigid body system model including the motor inertia and the inertia ratio or a dual inertia system model including the motor inertia, the inertia ratio, and the spring constant.

[0229] (Note 4)

[0230] The processing simulation device according to Supplement 2, wherein:

[0231] The control characteristic calculation unit 213 calculates the control characteristic using the position control proportional gain.

[0232] (Note 5)

[0233] The processing simulation device according to Supplement 2, wherein:

[0234] The control characteristic calculation unit 213 calculates the control characteristic using the speed loop gain, or the speed loop gain, the speed control integral gain, and the speed control proportional gain.

[0235] (Note 6)

[0236] The processing simulation device according to Supplement 1, wherein:

[0237] The motor characteristics include at least one of motor inertia, inertia ratio and spring constant,

[0238] The control characteristic comprises at least one of a position control proportional gain, a speed loop gain, a speed control integral gain and a speed control proportional gain,

[0239] The transfer characteristic calculation unit 214 changes at least one of the motor inertia, the inertia ratio, the spring constant, the position control proportional gain, the speed loop gain, the speed control integral gain, and the speed control proportional gain so that the transfer characteristic satisfies the predetermined requirement.

[0240] (Note 7)

[0241] The processing simulation device according to Supplement 1, wherein:

[0242] The transfer characteristic calculation unit 214 adds load inertia to motor inertia or combines motor inertia and load inertia via a spring element so that the transfer characteristic satisfies the predetermined requirement.

[0243] (Note 8)

[0244] A machining simulation method, wherein:

[0245] The following processing is performed by the computer:

[0246] A process for calculating motor characteristics based on motor information of a machine tool;

[0247] a process of calculating control characteristics of the motor control system based on control parameters of the motor control system of the machine tool;

[0248] A process of calculating a transfer characteristic satisfying a predetermined requirement based on the motor characteristic and the control characteristic;

[0249] a process of using the transfer characteristics to simulate the behavior of the machine tool,

[0250] The predetermined requirement includes at least one of a response frequency of position control, a response frequency of speed control, a natural vibration frequency of the machine tool, and a resonance frequency between a driving part and a driven part in the machine tool.

[0251] Description of Reference Numerals

[0252] 10Processing simulation system,

[0253] 100 Machine tool control device,

[0254] 101 Storage Department,

[0255] 200 machining simulation device,

[0256] 210 transfer characteristic generating unit,

[0257] 211 Control Information Acquisition Unit,

[0258] 212 Motor characteristics calculation unit,

[0259] 213 Control characteristics calculation unit,

[0260] 214 Transfer characteristic calculation unit,

[0261] 220 simulation execution unit.

Claims

1. A processing simulation device, characterized in that: have: a transfer characteristic generating unit that generates a transfer characteristic of the machine tool; and a simulation execution unit that uses the transfer characteristic to simulate the behavior of the machine tool, The transfer characteristic generating unit comprises: a control information acquisition unit that acquires control information including motor information of the machine tool and control parameters of a motor control system of the machine tool from a storage unit; a motor characteristic calculation unit that calculates motor characteristics based on the motor information; a control characteristic calculation unit that calculates a control characteristic of the motor control system based on the control parameter; as well as a transfer characteristic calculation unit that calculates the transfer characteristic satisfying a predetermined requirement based on the motor characteristic and the control characteristic, The predetermined requirement includes at least one of a response frequency of position control, a response frequency of speed control, a natural vibration frequency of the machine tool, and a resonance frequency of a driving part and a driven part in the machine tool.

2. The processing simulation device according to claim 1, characterized in that: The motor information includes at least one of the motor inertia, the inertia ratio, and the spring constant of the motor. The control parameter includes at least one of a position control proportional gain, a speed loop gain, a speed control integral gain, and a speed control proportional gain.

3. The processing simulation device according to claim 2, characterized in that: The motor characteristic calculation unit calculates the motor characteristic using a rigid body system model including the motor inertia and the inertia ratio or a dual inertia system model including the motor inertia, the inertia ratio, and the spring constant.

4. The processing simulation device according to claim 2, characterized in that: The control characteristic calculation section calculates the control characteristic using the position control proportional gain.

5. The processing simulation device according to claim 2, characterized in that: The control characteristic calculation section calculates the control characteristic using the speed loop gain, or the speed loop gain, the speed control integral gain, and the speed control proportional gain.

6. The processing simulation device according to claim 1, characterized in that: The motor characteristics include at least one of motor inertia, inertia ratio and spring constant, The control characteristic comprises at least one of a position control proportional gain, a speed loop gain, a speed control integral gain and a speed control proportional gain, The transfer characteristic calculation unit changes at least one of the motor inertia, the inertia ratio, the spring constant, the position control proportional gain, the speed loop gain, the speed control integral gain, and the speed control proportional gain so that the transfer characteristic satisfies the predetermined requirement.

7. The processing simulation device according to claim 1, characterized in that: The transfer characteristic calculation unit adds load inertia to motor inertia or combines motor inertia and load inertia using a spring element so that the transfer characteristic satisfies the predetermined requirement.

8. A processing simulation method, characterized in that: The following processing is performed by the computer: A process for calculating motor characteristics based on motor information of a machine tool; a process of calculating control characteristics of the motor control system based on control parameters of the motor control system of the machine tool; A process of calculating a transfer characteristic satisfying a predetermined requirement based on the motor characteristic and the control characteristic; as well as a process of using the transfer characteristics to simulate the behavior of the machine tool, The predetermined requirement includes at least one of a response frequency of position control, a response frequency of speed control, a natural vibration frequency of the machine tool, and a resonance frequency between a driving part and a driven part in the machine tool.

Images