Abstract:
A sinusoidal signal that is frequency-swept so as to have a frequency region in which each frequency has a different number of cycles and/or application duration is applied to a control system in a movement device that moves a movement target, time-series data for transmission characteristics obtained from said control system as a result of the application of the aforementioned sinusoidal signal is acquired, and said time-series data is subjected to spectral analysis. This allows the provision of a positioning control device and a frequency-characteristics measurement method that make it possible to optimize measuring precision while minimizing increases in the amount of time it takes to measure frequency characteristics.

Description:
TECHNICAL FIELD 
       [0001]    The present invention relates to a frequency-characteristics measurement method and a positioning control device that are used for controlling a position of a mobile body. 
       BACKGROUND ART 
       [0002]    In industrial machinery, such as various processing devices and mechatronics manufacturing/inspection devices, examples of primary factors for determining quality of manufactured products and mechatronics products, include accuracy of positioning a mobile body included in a device. For example, in semiconductor manufacturing inspection devices or devices for mounting a component on a substrate, accuracy of positioning control of a mobile body influences the quality of products. For example, in elevators, the accuracy is an important factor for determining safety and comfortable rides. Technology development for improving the accuracy of the positioning, has been pursued. 
         [0003]    Frequency characteristics of a mechanism system and a control system are used for designing and adjusting the above positioning control system. Measurement accuracy of the frequency characteristics influences accuracy of the positioning. For example, as a technique relating to measurement of the above frequency characteristics, PTL 1 (JP 10-339751 A) discloses an analog/digital coexisting simulating method. A signal level of an input signal, sweep start frequency, finish frequency, and an amount of a frequency step between the sweep start frequency and the finish frequency, are set. Then, a transient-characteristics analysis including an analog form and a digital form coexisting is performed from the sweep start frequency point. After that, a result of the output signal is subjected to a Fourier analysis. Signal intensity of each of a real part and an imaginary part at the input signal frequency point, is acquired so that a signal level and a phase are acquired. Until the sweep finish frequency, the analysis including the analog form and the digital form coexisting, and the Fourier analysis are repeatedly performed so that the output signal and frequency characteristics of the phase are acquired. 
       CITATION LIST 
     Patent Literature 
       [0004]    PTL: JP 10-339751 A 
       SUMMARY OF INVENTION 
     Technical Problem 
       [0005]    However, there are the following problems in the above related art. 
         [0006]    For example, in order to maintain measurement accuracy in a positioning control device using digital control, measurement is theoretically required until half of a sampling frequency (Nyquist frequency) of a positioning control system. However, when the sampling frequency is inhibited, for example, in order to shorten measurement time, in particular, the measurement accuracy of frequency characteristics is degraded in a high frequency region. Prolonging data acquisition time at each frequency can improve the measurement accuracy of the frequency characteristics. However, there is no indicator for to what extent the data acquisition time is set. Thus, it is thought that there is a case where the measurement time is unnecessarily long or a case where the measurement time is insufficient to acquire necessary measurement accuracy. 
         [0007]    In the above related art, data acquisition time for analyzing frequency characteristics of gain and the phase, is constant. Thus, there is a risk that the measurement accuracy in a high frequency region is degraded. Furthermore, since the data acquisition and the analysis are repeated in order to improve the accuracy of the frequency-characteristics measurement, the measurement time is required to be extremely long. 
         [0008]    The present invention has been made in consideration of the above problems. An object of the invention is to provide a positioning control device and a frequency-characteristics measurement method that are capable of preventing measurement time of frequency characteristics from being prolonged, and optimizing measurement accuracy. 
       Solution to Problem 
       [0009]    In order to achieve the above object, the present invention includes: a signal applying unit configured to apply a sinusoidal signal to a control system in a movement device that moves an object to be moved, the sinusoidal signal being frequency-swept so as to have a frequency region in which at least one of a cycle number and applying duration is different at each frequency; a time-series data acquisition unit configured to acquire time-series data of transmission characteristics acquired from the control system by applying the sinusoidal signal; and a spectrum analyzing unit configured to perform spectral analysis to the time-series data. 
       Advantageous Effects of Invention 
       [0010]    According to the present invention, the measurement time of the frequency characteristics can be prevented from being prolonged and the measurement accuracy can be optimized. 
     
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         [0011]      FIG. 1  is a schematic view of an entire configuration of a positioning control system according to a first embodiment. 
           [0012]      FIG. 2  is a schematic view of an entire configuration of a positioning control device according to the first embodiment. 
           [0013]      FIG. 3  is an exemplary block diagram of a control system in the positioning control device. 
           [0014]      FIG. 4  is a flow chart of processes of frequency-characteristics measurement. 
           [0015]      FIG. 5  is an exemplary graphical representation of a measurement result by a simulation of transmission characteristics in the related art, illustrating frequency characteristics relating to gain. 
           [0016]      FIG. 6  is an exemplary graphical representation of a measurement result by the simulation of transmission characteristics in the related art, illustrating frequency characteristics relating to phase. 
           [0017]      FIG. 7  is a graphical representation of a measurement result by a simulation of theoretical transmission characteristics, illustrating frequency characteristics relating to gain. 
           [0018]      FIG. 8  is a graphical representation of a measurement result by the simulation of theoretical transmission characteristics, illustrating frequency characteristics relating to phase. 
           [0019]      FIG. 9  is an exemplary graphical representation of discretization of a sinusoidal signal to be applied to an object to be measured, illustrating a case where the sine signal having 30 Hz is sampled with a frequency of 1 kHz. 
           [0020]      FIG. 10  is an exemplary graphical representation of discretization of a sinusoidal signal to be applied to the object to be measured, illustrating a case where the sine signal having 300 Hz is sampled with a frequency of 1 kHz. 
           [0021]      FIG. 11  is a graphical representation of a simulated result of ideal frequency characteristics including no discretization noise in a case where a sine wave having an amplitude of 1 is applied at each frequency, illustrating the frequency characteristics relating to gain. 
           [0022]      FIG. 12  is a graphical representation of a simulated result of ideal frequency characteristics including no discretization noise in a case where a sine wave having an amplitude of 1 is applied at each frequency, illustrating the frequency characteristics relating to phase. 
           [0023]      FIG. 13  is a graphical representation of a simulated result of frequency characteristics including discretization noise in a case where a cycle number has been made to be constant and a sine wave having an amplitude of 1 is applied at each frequency, illustrating the frequency characteristics relating to gain. 
           [0024]      FIG. 14  is a graphical representation of a simulated result of frequency characteristics including discretization noise in a case where the cycle number has been made to be constant and a sine wave having an amplitude of 1 is applied at each frequency, illustrating the frequency characteristics relating to phase. 
           [0025]      FIG. 15  is a graphical representation of the cycle number upon frequency-characteristics measurement according to the first embodiment. 
           [0026]      FIG. 16  is an exemplary graphical representation of a measurement result by a simulation of transmission characteristics according to the first embodiment, illustrating frequency characteristics relating to gain. 
           [0027]      FIG. 17  is an exemplary graphical representation of a measurement result of the simulation of transmission characteristics according to the first embodiment, illustrating frequency characteristics relating to phase. 
           [0028]      FIG. 18  is a schematic view of an entire configuration of a component mounting device according to a second embodiment. 
           [0029]      FIG. 19  is a schematic view of an entire configuration of a semiconductor manufacturing/inspection device according to a third embodiment. 
           [0030]      FIG. 20  is a schematic view of an entire configuration of a printed circuit board processing device according to a fourth embodiment. 
       
    
    
     DESCRIPTION OF EMBODIMENTS 
       [0031]    Embodiments of the present invention will be described below with reference to the drawings. 
       First Embodiment 
       [0032]    A first embodiment of the present invention will be described with reference to  FIGS. 1 to 17 . 
         [0033]      FIG. 1  is a schematic view of an entire configuration of a positioning control system according to the present embodiment. 
         [0034]    In  FIG. 1 , the positioning control system includes, a table driving device  205  illustrated as an example of an object to be controlled and an object to be measured according to the present embodiment, and the positioning control device  202  for controlling the positioning control system. 
         [0035]    The table driving device  205  schematically includes a base table  100 , a top table  110  as an object to be moved, an X axis direction driving mechanism  120  and a Y axis direction driving mechanism  130  included in a movement device for moving the top table  110 . 
         [0036]    The Y axis direction driving mechanism  130  includes a Y axis direction linear guide  131 , a Y axis direction driving motor stator  132 , and a Y axis direction linear scale  133  that are arranged in a Y axis direction on the base table  100 . The Y axis direction linear guide  131  includes a sliding unit, not illustrated, fit thereto. The sliding unit guides a movement of a Y table  126  of the X axis direction driving mechanism  120  in the Y axis direction. A Y axis direction motor needle  124  disposed on the Y table  126  is driven with respect to the Y axis direction motor stator  132  so that the Y table  126  can be driven along the Y axis direction linear guide  131 . A Y scale head  125  disposed on the Y table  126  detects the Y axis direction linear scale  133  so that a position (coordinates) of the Y table  126  in the Y axis direction can be detected. Note that, the Y axis direction linear scale  133  and the Y scale head  125  are included in a portion of a position detecting device for detecting a position of the top table  110  that is an object to be moved. 
         [0037]    The X axis direction driving mechanism  120  includes an X axis direction linear guide  121 , an X axis direction driving motor stator  122 , and an X axis direction linear scale  123  that are arranged in an X axis direction on the Y table  126 . The X axis direction linear guide  121  includes a sliding unit, not illustrated, fit thereto. The sliding unit guides a movement of the top table  110  in the X axis direction. An X axis direction motor needle  111  disposed on the top table  110  is driven with respect to the X axis direction motor stator  122  so that the top table  110  can be driven along the X axis direction linear guide  121 . An X scale head.  112  disposed on the top table  110  detects the X axis direction linear scale  123  so that a position (coordinates) of the top table  110  in the X axis direction can be detected. 
         [0038]      FIG. 2  is a schematic view of an entire configuration of the positioning control device according to the present embodiment.  FIG. 3  is an exemplary block diagram of a control system in the positioning control device. 
         [0039]    As illustrated in  FIG. 3 , the control system in the positioning control device includes: for example, an object to be controlled  104  corresponding to the direction driving mechanism  120  and the Y axis direction driving mechanism  130  of the object to be measured  205 ; a command generating unit  101  for generating and outputting a position command r using previously set movement parameters, such as a target movement amount, velocity, and acceleration; a differentiator  105  for outputting a difference e between the position command r that is the output of the command generating unit  101  and a current position y that is output of the object to be controlled  104 , to a controller  102 ; the controller  102  for calculating and outputting an operation amount u 1  with respect to the object to be controlled  104 ; and an adder  103  for outputting an operation amount u 2  that is the sum of the operation amount u 1  that is the output of the controller  102  and a virtual thrust disturbance d, to the object to be controlled  104 . For example, the command generating unit  101 , the controller  102 , and the differentiator  105  correspond to constituent functions of positioning control functional unit  217  to be described later. 
         [0040]    Transmission characteristics from the thrust disturbance d to the operation amount u 2  are referred to as a sensitivity function, and are expressed by a transmission function in Mathematical Formula 1 below. 
         [0000]    
       
         
           
             
               
                 
                   
                     G 
                     S 
                   
                   = 
                   
                     
                       
                         u 
                         2 
                       
                       d 
                     
                     = 
                     
                       1 
                       
                         1 
                         + 
                         
                           C 
                           · 
                           P 
                         
                       
                     
                   
                 
               
               
                 
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                     Mathematical 
                      
                     
                         
                     
                      
                     Formula 
                      
                     
                         
                     
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                     1 
                   
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         [0041]    Transmission characteristics from the thrust disturbance d to the operation amount u 1  are referred to as a complementary sensitivity function, and are expressed by transmission characteristics in Mathematical Formula 2 below. 
         [0000]    
       
         
           
             
               
                 
                   
                     G 
                     cS 
                   
                   = 
                   
                     
                       
                         u 
                         1 
                       
                       d 
                     
                     = 
                     
                       
                         
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                           · 
                           P 
                         
                         
                           1 
                           + 
                           
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                             · 
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                         - 
                         
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                           S 
                         
                       
                     
                   
                 
               
               
                 
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                     Mathematical 
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                     Formula 
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                     2 
                   
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         [0042]    Transmission characteristics from the operation amount u 2  to the operation amount u 1  are referred to as open loop characteristics, and are expressed by transmission characteristics in Mathematical Formula 3 below. 
         [0000]    
       
         
           
             
               
                 
                   
                     G 
                     L 
                   
                   = 
                   
                     
                       
                         u 
                         1 
                       
                       
                         u 
                         2 
                       
                     
                     = 
                     
                       
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                         · 
                         P 
                       
                       = 
                       
                         
                           
                             G 
                             cS 
                           
                           
                             G 
                             S 
                           
                         
                         = 
                         
                           
                             1 
                             
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                               S 
                             
                           
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                     Mathematical 
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                      
                     Formula 
                      
                     
                         
                     
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                     3 
                   
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         [0043]    In a case where the operation amount u 2  and the current position y have been extracted in a state where the operation amount u 1  has been made to be zero by, for example, the controller  102  (control has not been performed), transmission characteristics from the operation amount u 2  to the current position y are referred to as object-to-be-controlled characteristics, and are expressed by a transmission function in Mathematical Formula 4 below in a state where the operation amount u 1  has been made not to be zero (the control has been performed), the transmission characteristics from the operation amount u 2  to the current position y are referred to as a setting function, and are expressed by the product of the sensitivity function and the object-to-be-controlled characteristics as in Mathematical Formula 5 below. That is, in this case, characteristics of the object to be controlled  104  can be calculated by the setting function and the sensitivity function. 
         [0000]    
       
         
           
             
               
                 
                   
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                     P 
                   
                   = 
                   
                     
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                     P 
                   
                 
               
               
                 
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         [0044]    Typically, the open loop characteristics are used for evaluating stability of the control system. The sensitivity function is used for evaluating disturbance suppression characteristics, and the complementary sensitivity function is used for evaluating response characteristics. Therefore, the open loop characteristics, the sensitivity function, and the complementary sensitivity function are measured so that the control system can be evaluated and a parameter of the controller  102  can be adjusted. The object-to-be-controlled characteristics are measured so that a structure and the parameter of the controller  102  can be designed and the control system can be constructed. 
         [0045]    Note that, the block diagram of the uniaxial control system is only illustrated in  FIG. 3  in order to simplify the descriptions. For a multiaxial control system, interference between axes is prevented so that a control system of each axis includes the same block. Furthermore, for an object to be controlled (object to be measured) of a multiple input/output system including a plurality of inputs or outputs, a control system of each pair of the input and the output includes the same block. 
         [0046]    The positioning control system illustrated in  FIG. 3  is only an example. For example, a configuration of the positioning control system according to the present embodiment is not limited to this. That is, for example, the input of the controller  102  may include the operation amounts u 1  and u 2 , the current position y, and the position command r in addition to the difference e. Various configurations can be arranged for purposes. Similarly,  FIG. 3  is exemplary transmission characteristics necessary for designing and adjusting the controller  102 , and, for example, a configuration of the object to be measured is not limited to this. That is, in a case where transmission characteristics between two points of an object to be controlled is measured, a virtual disturbance may be applied and a quantity of state of each of the two points may be extracted so that the transmission characteristics may be measured. Selection can be freely performed for purposes. 
         [0047]    In  FIG. 2 , the positioning control device  202  schematically includes: a display unit  204  for displaying various information and a setting screen; an input device  201  for inputting the various information and setting values; the positioning control functional unit  217  for controlling a movement of the object to be measured  205  (the table driving device  205  in  FIG. 1 : hereinafter, simply referred to as the object to be measured  205 ); and a frequency-characteristics measurement functional unit  203  for measuring frequency characteristics of the object to be measured  205 . 
         [0048]    The positioning control functional unit  217  controls movements of the X axis direction driving mechanism  120  and the Y axis direction driving mechanism  130  of the object to be measured (table driving device)  205  so as to move the top table  110 . Then, the positioning control functional unit  217  performs positioning of the top table  110  with respect to the base table  100 . 
         [0049]    The frequency-characteristics measurement function  203  includes a storage unit.  206 , a frequency calculating unit  207 , a cycle-number calculating unit  208 , a sine wave generating unit (signal applying unit)  209 , and a gain/phase calculating unit  210 . 
         [0050]    The storage unit  206  stores: setting values  212 , such as a sine wave applying unit and an output signal corresponding to transmission characteristics required to be measured, a frequency range and a frequency interval to be measured, a sine-wave cycle-number and measurement time at each frequency, and a sine wave amplitude; various default values  211  previously set; frequency data  213 , cycle-number data  214 , and frequency-characteristics data  216  that are results calculated by the frequency calculating unit  207 , the cycle-number calculating unit  208 , and the gain/phase calculating unit  210 ; and time-series data  215  output from the object to be measured  205 . 
         [0051]    The frequency calculating unit  207  calculates the frequency data  213  based on, for example, the measurement frequency range and the number of frequency points included in the setting values  212  that are the default values  211 , and then stores the frequency data  213  in the storage device  206 . 
         [0052]    The cycle-number calculating unit  208  calculates the cycle-number data  214  according to measurement at each frequency based on, for example, sampling time included in the setting values  212  and the frequency data  213 , and stores the cycle-number data  214  in the storage device  206 . 
         [0053]    The sine wave generating unit  209  generates a sine wave determined based on the sine wave amplitude included in the setting values  212  and the frequency data  213 , by a cycle number determined based on the cycle-number data  214 . Then, the sine wave generating unit  209  applies the sine wave by the cycle number, to the object to be measured  205 . 
         [0054]    The gain/phase calculating unit  210  calculates the frequency-characteristics data  216  at a measurement frequency, based on the time-series data  215  and the frequency data  213 , and stores the frequency-characteristics data  216  in the storage device  206 . 
         [0055]    The display unit  204  displays a cycle number at each frequency used for measurement and measured frequency characteristics, using, for example, the frequency data  213 , the cycle-number data  214 , and the frequency-characteristics data  216 . Note that, the data to be displayed may be constituent for purposes, for example, may include the time-series data  215 . 
         [0056]    According to the present embodiment, the positioning control device having the above configuration measures target transmission characteristics of the object to be measured  205 . 
         [0057]    Here, frequency-characteristics measurement according to the present embodiment, will be described with reference to  FIG. 4 . 
         [0058]      FIG. 4  is a flow chart of processes of the frequency-characteristics measurement. 
         [0059]    In  FIG. 4 , first, a normal positioning movement is stopped in the frequency-characteristics measurement. An operator uses the input unit  201  so as to set setting values, such as a sine wave applying unit and an output signal corresponding to transmission characteristics required to be measured, a frequency range and a frequency interval to be measured, a sine-wave cycle-number and measurement time at each frequency, and a sine wave amplitude (Step S 301 ). 
         [0060]    For example, upon measuring the open loop characteristics in Mathematical Formula 3 above in the control system illustrated in  FIG. 3 , the sine wave applying unit should be set to be d, and the output signal should be set to be u 1  and u 2 . Note that, the setting values each are set by an operator or a user. The default values stored in the device may be used for all the setting values or a part of the setting values. 
         [0061]    Next, a frequency and the number of all frequency points k to be measured, are calculated based on, for example, the frequency range and the frequency interval that have been set (Step S 302 ). A sine-wave cycle-number at each measurement frequency, is calculated and set (Step S 303 ). The frequency-characteristics measurement is performed after the parameters have been set (Step S 304 ). In the calculation of the sine-wave cycle-number at each measurement frequency at Step S 303 , a calculation is performed so as to have a frequency region in which at least one of a cycle number and applying duration is different at each frequency (to be described later). 
         [0062]    In the frequency-characteristics measurement at Step S 304 , first, initialization of a sine wave to be applied for setting a frequency sending index i for determining the frequency to be measured, security of an output signal storage region, initialization necessary for the frequency-characteristics measurement, are performed (Step S 305 ). 
         [0063]    Next, the index i is updated so that the frequency to be measured is updated to be f(i) (Step S 306 ). The sine wave generating unit applies a sine wave having the frequency f(i) and an amplitude set, to the object to be measured  205  (Step S 307 ). An output signal in the measurement at the index i, stored (Step S 308 ). Gain/phase characteristics at the index i are calculated (Step S 09 ). 
         [0064]    The gain characteristics g and the phase characteristics p of the signal can be calculated by Mathematical Formulae 6 and 7 below using a cosine wave component. Re and a sine wave component Im at the frequency f(i) of the output signal. 
         [0000]    
       
         
           
             
               
                 
                   g 
                   = 
                   
                     
                       
                         Re 
                         2 
                       
                       + 
                       
                         Im 
                         2 
                       
                     
                   
                 
               
               
                 
                   [ 
                   
                     Mathematical 
                      
                     
                         
                     
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                     Formula 
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                   ] 
                 
               
             
             
               
                 
                   p 
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                         - 
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         [0065]    Similarly, for example, gain transmission characteristics Gt and phase transmission characteristics Pt from a signal A to a signal B, can be calculated by Mathematical Formulae 8 and 9 below using a cosine wave component ReA and a sine wave component ImA of the signal A and a cosine wave component ReB and a sine wave component ImB of the signal B. 
         [0000]    
       
         
           
             
               
                 
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                     Mathematical 
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                     8 
                   
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         [0066]    Here, it is determined whether measurement of all frequencies to be measured that have been set has been completed (Step S 310 ). In a case where a determined result is NO, the series of processing of Steps S 306  to S 309  is repeated until the determining result at Step S 310  becomes YES. In a case where the determined result at Step S 310  is YES, for example, the frequency characteristics that has been measured and the cycle number that has been calculated, are displayed on the display unit  204  (Step S 311 ) after passing through Step S 304 . Then, the processing is completed. 
         [0067]    Note that, in the frequency-characteristics measurement illustrated in  FIG. 4 , for example, the display at Step S 311  may be configured to display every time a calculated result in the gain/phase calculation at Step S 309  is output. The gain/phase calculating at Step S 308  may be performed after the measurement of all frequencies has been completed, namely, after Step S 304 . 
         [0068]    Here, the frequency-characteristics measurement according to the present embodiment will be described in detail in comparison with the related art. 
         [0069]      FIGS. 5 and 6  are exemplary graphical representations of measurement results by a simulation of transmission characteristics in the related art.  FIG. 5  is the graphical representation of frequency characteristics relating to gain.  FIG. 6  is the graphical representation of frequency characteristics relating to phase.  FIGS. 7 and 8  are graphical representations of measurement results by a simulation of theoretical transmission characteristics.  FIG. 7  is the graphical representation of frequency characteristics relating ng to gain.  FIG. 8  is the graphical representation of frequency characteristics relating to phase. 
         [0070]    In the related art illustrated in  FIGS. 5 and 6 , a measurement cycle number for each frequency has been made to be constant. A state where a sine wave to be applied and a signal to be output include no external noise, is provided. However, the transmission characteristics in the related art illustrated in  FIGS. 5 and 6  have agreement in a low frequency region but difference in a high frequency region of more than 90 Hz in comparison with the theoretical transmission characteristics illustrated in  FIGS. 7 and 8 . Since a condition in which the signal to be applied and the output signal do not include the external noise, is provided, it is thought that the difference in the measurement results of transmission functions is caused by a measurement error due to discretization of the input/output signals. 
         [0071]      FIGS. 9 and 10  are exemplary graphical representations of discretization of sinusoidal signals to be applied to an object to be measured.  FIG. 9  illustrates a case where the sinusoidal signal having 30 Hz is sampled with a frequency of 1 kHz.  FIG. 10  illustrates a case where the sinusoidal signal having 300 Hz is sampled with a frequency of 1 kHz. 
         [0072]    As illustrated in  FIG. 9 , in a case where a frequency region of the sinusoidal signal (30 Hz) is relatively lower than the sampling frequency (1 kHz), the sine wave to be applied can be achieved to be substantially a theoretical sine wave. However, in a case where a frequency region of the sinusoidal signal (300 Hz) is relatively higher than the sampling frequency (1 kHz), the sine wave to be applied cannot be achieved to be a theoretical sine wave. That is, the disagreement between the sine wave after discretization and the theoretical sine wave, becomes noise caused by the discretization (discretization noise), and causes the measurement error illustrated in  FIGS. 5 and 6 . 
         [0073]      FIGS. 11 and 12  are graphical representations of ideal frequency-characteristics simulated results including no discretization noise in a case where a sine wave having an amplitude of 1 has been applied at each frequency.  FIG. 11  is the graphical representation of the frequency characteristics relating to gain.  FIG. 12  is the graphical representation of the frequency characteristics relating to phase.  FIGS. 13 and 14  are graphical representations of simulated results of frequency characteristics including the discretization noise in a case where a cycle number has been made to be constant and a sine wave having an amplitude of 1 has been applied at each frequency.  FIG. 13  illustrates the frequency characteristics relating to gain.  FIG. 14  illustrates the frequency characteristics relating to phase. 
         [0074]    As illustrated in  FIGS. 11 to 14 , it can be seen that the frequency characteristics of the applied sine wave are degraded in accuracy due to the discretization noise. Since the applied sine wave is output by the frequency-characteristics measurement function, the applied sine wave has been known. Therefore, according to the present embodiment, the measurement error of the applied sine wave due to the discretization noise is defined as an indicator, and a cycle number is calculated and used for the measurement. Thus, measurement accuracy is improved. 
         [0075]    In  FIGS. 13 and 14 , gain characteristics G 1  of the applied sine wave are expressed by Mathematical Formula 10 below. Here, N is a sample number (integer) of measurement time. A relationship between the sample number N and the cycle number C is expressed by Mathematical Formula 11 below. A relationship between the sample number N and the measurement time T is expressed by Mathematical Formula 12 below. Note that f is a measurement frequency and Ts is sample time in Mathematical Formulae 10 to 12. 
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         [0076]    In the applied sine wave, gain characteristics including no discretization noise become amplitude, and thus have been known. Therefore, when a measurement error tolerated by the gain characteristics G 1  is made to be defined as an indicator, only the sample number N is an unknown variable in Mathematical Formula 10 above. Mathematical Formula 10 above is solved with respect to the sample number N so that the cycle number C at each frequency is acquired by Mathematical Formula 11 above. Similarly, the measurement time T at each frequency is acquired by Mathematical Formula 12 above. Here, a method for solving Mathematical Formula 10 above with respect to the sample N may be any of an analytical solution and a numerical solution. Furthermore, Mathematical Formula 10 may be solved with respect to an approximate expression thereof. A cycle number to be used may be the cycle number C acquired, by Mathematical Formula 11 above, or more. Measurement time to be used may be the measurement time T acquired by Mathematical Formula 12 above, or more. 
         [0077]    According to the present embodiment, the cycle number or the measurement time that have been calculated above is used so that the frequency characteristics with high accuracy can be measured in a short time. 
         [0078]    Note that, according to the present embodiment, the gain characteristics of the applied sine wave have been illustrated in Mathematical Formula 10 above, but a calculating method and an expression are not limited to the gain characteristics. That is, for example, the signal to be used for the calculation may be an output signal. The characteristics to be used may be phase characteristics. 
         [0079]      FIG. 15  is a graphical representation of the cycle number upon the frequency-characteristics measurement according to the present embodiment. 
         [0080]      FIG. 15  has been calculated by Mathematical Formula 10 above, and includes a frequency region  701  in which the cycle number is constant at the minimum cycle number set, a frequency region  702  in which the cycle number is variable, and a frequency region  703  in which the cycle number is constant at the maximum cycle number set. 
         [0081]    The minimum cycle number Cmin is set in consideration of external noise. In a case where the cycle number C acquired by Mathematical Formula 10 above is less than the minimum cycle number Cmin (C&lt;Cmin), a cycle number Cm to be used for the measurement is made to be Cmin (Cm=Cmin). Accordingly, the frequency region  701  in which the cycle number Cm is constant in the low frequency region, can be made. 
         [0082]    The maximum cycle number Cmax is set from entire measurement time or a frequency region in which measurement accuracy is secured. In a case where the cycle number C acquired by Mathematical Formula 10 above is the maximum cycle number Cmax or less (C≦Cmax), the cycle number Cm to be used for the measurement is made to be the cycle number C (Cm=C). In a case where the cycle number C exceeds the maximum cycle number Cmax (C&gt;Cmax) the cycle number Cm to be used for the measurement is made to be the maximum cycle number Cmax (Cm=Cmax). Accordingly, the frequency region  703  in which the cycle number Cm is constant in the high frequency region, can be made, and the region  702  in which the cycle number Cm is variable, can be made. 
         [0083]    Note that cycle-number characteristics are not limited to  FIG. 15 . That is, the minimum cycle number and the maximum cycle number may be arbitrarily determined. In a case where there are one or more frequency regions each in which the cycle number is variable, the number of frequency regions in which the cycle number is fixed may be zero or more. Furthermore, the same may be true of the measurement time. 
         [0084]      FIGS. 16 and 17  are exemplary graphical representations of measured results of a simulation of transmission characteristics according to the present embodiment.  FIG. 16  is the graphical representation of frequency characteristics relating to gain.  FIG. 17  is the graphical representation of frequency characteristics relating to phase. 
         [0085]    According to the present embodiment, since the measurement cycle number illustrated in  FIG. 15  is used, there is agreement in a frequency region of up to 400 Hz as illustrated in  FIGS. 16 and 17  in comparison with the theoretical transmission characteristics (refer to  FIGS. 7 and 8 ). That is, it can be seen that the frequency characteristics with high accuracy can be measured according to the present embodiment in comparison with the transmission characteristics in the related art (refer to  FIGS. 5 and 6 ). In other words, the frequency region in which the cycle number is variable is provided as in the present embodiment so that the frequency characteristics with high accuracy can be measured in a short time. 
         [0086]    Effects according to the present embodiment including the above constituents, will be described. 
         [0087]    Typically, in order to maintain measurement accuracy in a positioning control device using digital control, measurement is theoretically required until half of a sampling frequency (Nyquist frequency) of a positioning control system. However, when the sampling frequency is inhibited, for example, in order to shorten measurement time, in particular, the measurement accuracy of frequency characteristics is degraded in a high frequency region. Prolonging data acquisition time at each frequency can improve the measurement accuracy of the frequency characteristics. However, there is no indicator for to what extent the data acquisition time is set. Thus, it is thought that there is a case where the measurement time is unnecessarily long or a case where the measurement time is insufficient to acquire necessary measurement accuracy. 
         [0088]    For example, two methods can be considered in order to reduce a measurement error due to discretization noise and improve measurement accuracy. One method shortens sampling time as a reference of discretization, improves feasibility of a signal even in a high frequency region, and reduces discretization noise so as to improve the measurement accuracy. However, sampling time, as a control period, for positioning control is used in the positioning control device. Therefore, even when sampling time shorter than the control period is achieved for the frequency-characteristics measurement, actual sampling time becomes the control period in a control loop. Thus, no effect can be expected. Another method increases a cycle number to be used for the measurement and increase signal intensity of a measurement frequency so as to improve the measurement accuracy. That is, increasing the cycle number is effective for the noise-resistant frequency-characteristics measurement. However, since discretization noise and external noise are unified and dealt with in the known art, there is no indicator for setting the cycle number or the measurement time. This is because external noise depends on a measurement environment and cannot be previously determined. 
         [0089]    In the related art, data acquisition time for analyzing frequency characteristics of gain and phase is constant. Thus, there is a risk that measurement accuracy is degraded in a high frequency region. Furthermore, since data acquisition and analysis are repeated in order to improve accuracy of the frequency-characteristics measurement, extremely long measurement time is required. 
         [0090]    In contrast, according to the present embodiment, a sine wave frequency-swept so as to have the frequency region in which at least one of the cycle number or applying duration as different at each frequency, has been made to be applied to the control system in the movement device for moving the object to be moved. The measurement time of the frequency characteristics can be prevented from being prolonged and the measurement accuracy can be optimized. The frequency characteristics with high accuracy can be measured in a short time. 
       Second Embodiment 
       [0091]    A second embodiment of the present invention will be described with reference to  FIG. 18 . 
         [0092]    According to the present embodiment, the positioning control device according to the first embodiment has been applied to a component mounting device as a positioning control system. The component mounting device includes a positioning control device  202  that controls operation of the component mounting device and measures frequency characteristics of the component mounting device. 
         [0093]      FIG. 18  is a schematic view of an entire configuration of the component mounting device according to the present embodiment. 
         [0094]    In  FIG. 18 , a Y beam  1303  movable in a Y axis direction in the drawing, is driven and positioned by two Y linear motors  1301  and  1302  in the Y axis direction with respect to a base. Similarly, a mounting head  1305  is driven and positioned by an X linear motor  1304  in an X axis direction with respect to the Y beam  1303 . Accordingly, the mounting head  1305  is freely positioned on an XY plane. The mounting head  1305  includes a plurality of suction nozzles  1306 . Each of the plurality of suction nozzles  1306  sucks, holds a component, and is moved in a Z direction so as to mount the component on an arbitrary position on a printed circuit board  1307 . 
         [0095]    Other components are similar to those according to the first embodiment. 
         [0096]    According to the present embodiment including the above configuration, an effect similar to that according to the first embodiment, can be acquired. 
       Third Embodiment 
       [0097]    A third embodiment of the present invention will be described with reference to  FIG. 19 . 
         [0098]    According to the present embodiment, the positioning control device according to the first embodiment has been applied to a semiconductor manufacturing/inspection device as a positioning control system. The semiconductor manufacturing/inspection device includes a positioning control device  202  that controls operation of the semiconductor manufacturing/inspection device and measures frequency characteristics of the semiconductor manufacturing/inspection device. 
         [0099]      FIG. 19  is a schematic view of an entire configuration of the semiconductor manufacturing/inspection device according to the present embodiment. 
         [0100]    In  FIG. 19 , a Y linear guide  1402  is disposed in a Y axis direction in the drawing on a base  1401 . A Y table  1404  is restricted so as to be free only in the Y axis direction. The Y table  1404  is positioned in the Y axis direction by a Y linear motor  1403 . A top table  1407  is restricted by an X linear guide  1405  so as to be free only in an X axis direction with respect to the Y table  1404 . The top table  1407  is positioned in the K axis direction by an X linear motor  1406 . Accordingly, a wafer  1408  disposed on the top table  1407  is positioned in the KY axes directions with respect to the base  1404 . For example, an optical beam or an electron beam  1409  for the semiconductor manufacturing or the inspection on is irradiated on the wafer  1408  so that the semiconductor manufacturing and inspection are performed. 
         [0101]    Other components are similar to those according to the first embodiment. 
         [0102]    According to the present embodiment including the above configuration, an effect similar to that according to the first embodiment, can be acquired. 
       Fourth Embodiment 
       [0103]    A fourth embodiment according to the present invention will be descried with reference to  FIG. 20 . 
         [0104]    According to the present embodiment, the positioning control device according to the first embodiment has been applied to a printed circuit board processing device as a positioning control system. The printed circuit board processing device includes a positioning control device  202  that controls operation of the printed circuit board processing device and measures frequency characteristics of the printed circuit board processing device. 
         [0105]      FIG. 20  is a schematic view of an entire configuration of the printed circuit board processing device according to the present embodiment. 
         [0106]    In  FIG. 20 , a table  1503  is disposed on a bed.  1  through two guides  1504  so as to be free in a Y axis direction in the drawing. A Y feed screw  1505  positions the table  3  in the Y axis direction. A portal-typed column rail  1502  is disposed on the bed  1501 . A sliding ng plate  1508  is fit to a side surface of the portal-typed column rail  1506  through an K guide  1506 . The sliding plate  1508  is positioned in an X axis direction with respect to the portal-typed column rail  1506  by an X driving unit (not illustrated). Accordingly, the sliding plate  1508  and the table  1503  are relatively positioned in the XY axes directions. A plurality of drill units  1507  are disposed on the sliding plate  1508 , and performs processing of a printed circuit board disposed on the table  1503 . 
         [0107]    Other components are similar to those according to the first embodiment. 
         [0108]    According to the present embodiment including the above configuration, an effect similar to that according to the first embodiment, can be acquired. 
       REFERENCE SIGNS LIST 
       [0000]    
       
           100  base table 
           110  top table 
           111  X axis direction motor needle 
           120  X axis direction driving mechanism 
           121  X axis direction linear guide 
           122  X axis direction driving motor stator 
           123  X axis direction linear scale 
           124  Y axis direction driving motor needle 
           125  scale head 
           126  Y table 
           130  Y axis direction driving mechanism 
           131  Y axis direction linear guide 
           132  Y axis direction driving motor stator 
           133  Y axis direction linear scale 
           201  input device 
           202  positioning control device 
           203  frequency-characteristics measurement functional unit 
           204  display unit 
           205  object to be measured (table driving device) 
           206  storage unit 
           207  frequency calculating unit 
           208  cycle-number calculating unit 
           209  sine wave generating unit (signal applying unit) 
           210  gain/phase calculating unit 
           211  default values 
           212  setting values 
           213  frequency data 
           214  cycle-number data 
           215  time-series data 
           216  frequency-characteristics data 
           217  positioning control functional unit