JP2022113538A - fluid actuator - Google Patents

Abstract

To provide a fluid actuator that is able to reduce adverse effect of pipe resonance on a control device.SOLUTION: An air actuator using air as a working fluid comprises: a slider that drives a work table 110 to be driven by air; a control device 300 that calculates an amount u of operation of air, based on an input drive command Posref and drives and controls the work table 110; a servo valve that supplies air, based on the amount u of operation calculated by the control device 300; and a pipe in which air circulates between the slider and the servo valve; wherein the control device 300 comprises a phase advance/delay compensation element 380 including a phase advance compensation element in a numerator of a transmission function and a phase delay compensation element in a denominator of the transmission function and used to calculate the amount of operation.SELECTED DRAWING: Figure 3

Description

The present invention relates to control technology for fluid actuators.

A control device for an air actuator that uses air as a working fluid controls the amount of air supplied based on an input position command to drive an object to a desired position. Various control techniques such as feedback control (hereinafter also abbreviated as FB control) and feedforward control (hereinafter sometimes abbreviated as FF control) are used to quickly and accurately drive a driven object to a desired position. used.

JP-A-5-184178

In the air actuator, piping resonance may occur due to the circulation of air in the piping that supplies air to the drive unit. Since piping resonance adversely affects the operation of the control device, it must be removed by a notch filter or the like. In general, the notch filter transfer function contains homogeneous polynomials in the numerator and denominator of the variable s containing the notch frequency. Although the notch filter numerator polynomial can cancel the pipe resonance denominator polynomial, the remaining notch filter denominator polynomial can still interfere with controller operation near the notch frequency.

SUMMARY OF THE INVENTION The present invention has been made in view of such circumstances, and an object of the present invention is to provide a fluid actuator capable of reducing adverse effects of pipe resonance on a control device.

In order to solve the above problems, a fluid actuator according to one aspect of the present invention includes a drive unit that drives an object to be driven by a working fluid; A control device for control, a working fluid supply unit for supplying the working fluid based on the operation amount calculated by the control device, and a pipe through which the working fluid flows between the driving unit and the working fluid supply unit. The control device includes a phase lead compensating element in the numerator of the transfer function, a phase lag compensating element in the denominator of the transfer function, and a phase lead/lag compensating element used for calculating the actuation amount.

In the phase lead/lag compensating element of this embodiment, the polynomials of the numerator phase lead compensating element and the denominator phase lag compensating element can be designed independently of each other. Therefore, the polynomial of the denominator of the pipe resonance can be canceled by the polynomial of the phase lead compensating element of the numerator, and at the same time, the natural angular frequency of the polynomial of the phase lag compensating element of the denominator can be set to a frequency that has little effect on the operation of the control device.

Another aspect of the invention is also a fluid actuator. This fluid actuator includes a drive unit that drives a driven object with a working fluid, a control device that calculates the amount of actuation of the working fluid based on an input drive command, and drives and controls the driven object, and an actuation amount calculated by the control device. and a pipe through which the working fluid flows between the driving portion and the working fluid supply and pipe resonance occurs at a frequency near the bandwidth of the control device. The control device includes a phase lead compensating element in the numerator of the transfer function, a phase lag compensating element in the denominator of the transfer function, and a phase lead/lag compensating element used for calculating the actuation amount. A natural angular frequency of the phase lag compensating element is arranged on a higher frequency side farther from the bandwidth than the natural angular frequency of the phase lead compensating element.

In the phase lead/lag compensating element of this aspect, since the natural angular frequency of the polynomial of the phase lag compensating element in the denominator is on the higher side farther from the bandwidth of the control device than the natural angular frequency of the phase lead compensating element, can reduce the adverse effects on the operation of

Any combination of the above constituent elements, and any conversion of expressions of the present invention into methods, devices, systems, recording media, computer programs, etc. are also effective as embodiments of the present invention.

ADVANTAGE OF THE INVENTION According to this invention, the fluid actuator which can reduce the bad influence to the control apparatus by piping resonance can be provided.

1 is a perspective view of an air stage to which a fluid actuator of this embodiment is applied; FIG. It is a sectional view of an air actuator. 1 is a block diagram schematically showing the configuration of a control device for an air actuator; FIG. FIG. 4 is a diagram showing an example arrangement of various frequencies that affect the operation of the control device; FIG. 10 is a diagram showing the effect of a phase lead/lag compensating element;

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, embodiments for carrying out the present invention will be described in detail with reference to the drawings. In the description and drawings, the same or equivalent components, members, and processes are denoted by the same reference numerals, and overlapping descriptions are omitted as appropriate. The scales and shapes of the illustrated parts are set for convenience in order to facilitate explanation, and should not be construed as limiting unless otherwise specified. The embodiments are illustrative and do not limit the scope of the invention in any way. Not all features or combinations thereof described in the embodiments are essential to the invention.

FIG. 1 is a perspective view of an air stage to which the fluid actuator of this embodiment is applied. The air stage 100 mainly includes a surface plate 102, a vibration isolator 104, a vibration isolator 106, a work table 110, one X-axis air actuator 120, and two Y-axis air actuators 130A and 130B (hereinafter referred to as Y-axis air actuators 130A and 130B). Actuator 130). The surface plate 102 is supported by an anti-vibration table 104 . The air stage 100 has an H-shaped structure in which two air actuators are provided, the upper axis being the X axis and the lower axis being the Y1 and Y2 axes. The vibration isolator 106 reduces vibration from the floor where the air stage 100 is arranged, and suppresses vibration of the surface plate 102 .

The X-axis air actuator 120 and the Y-axis air actuator 130 are fluid actuators that use air as a working fluid to drive the work table 110 along the X-axis and the Y-axis, respectively. The X-axis air actuator 120 has a guide (square shaft) 122, a slider 124, a servo valve 126 (not shown), and a pipe 128 (not shown). Similarly, the Y-axis air actuator 130 has guides 132 , sliders 134 , servo valves 136 and piping 138 . Work table 110 is provided on slider 124 . Both ends of the guide 122 are supported by sliders 134 of the Y-axis air actuators 130A and 130B, respectively.

In the configuration of the air actuators 120 and 130 described above, the sliders 124 and 134 constitute a drive section that drives the worktable 110 as a drive target along the X-axis and the Y-axis. Further, the servo valves 126 and 136 constitute working fluid supply units that supply air to the sliders 124 and 134 based on the intake/exhaust amount, which is the working amount of air calculated by a control device to be described later. Piping 128, 138 circulates air between the drive and the working fluid supply.

When air flows through the pipes 128, 138, pipe resonance, which is a type of mechanical resonance, occurs. The resonance frequency ω ₀ of the pipe resonance is approximately represented by the following equation for the Helmholtz resonator.
ω ₀ =c(S/VL) ^1/2
Here, c is the speed of sound in air, S is the cross-sectional area of the pipes 128 and 138, V is the volume of the pipes 128 and 138 from the servo valves 126 and 136 to the sliders 124 and 134, and L is the air flow through the pipes 128 and 138. It corresponds to the length that feeds the sliders 124 , 134 . When this resonant frequency ω ₀ approaches the bandwidth of the controller (generally expressed in the Bode plot as the frequency at which the gain is 3 dB lower than the low frequency range), the operation of the controller is adversely affected. There is no problem if the resonance frequency ω ₀ can be made sufficiently higher than the bandwidth by shortening the pipe length L, but it may be difficult due to constraints such as the layout of the device. In one example of the air stage 100 investigated by the present inventor, each frequency was as follows. Bandwidth of control device: about 15 Hz, resonance frequency ω ₀ of pipe resonance: about 50-80 Hz, resonance frequency of mechanical resonance other than pipe resonance: 200 Hz or more. As will be described later, the fluid actuator of the present invention is particularly suitable for systems in which such pipe resonance cannot be ignored.

A position sensor 140 detects the position of the worktable 110 in the X-axis direction. A position sensor 142 detects the position of the work table 110 in the Y-axis direction.

FIG. 2 is a cross-sectional view of the air actuator. The X-axis air actuator 120 has a guide 122 , a slider 124 , a servo valve (spool valve) 126 and a pipe 128 .

A static pressure bearing is formed between the guide 122 and the slider 124, and the air pressure constantly supplied between the outer peripheral surface of the guide 122 and the inner peripheral surface of the slider 124 floats the slider 124 from the guide 122 without contact. It is movable in the X-axis direction.

The slider 124 is provided with a servo chamber 150 as an internal space, which is partitioned into a positive side chamber 152 and a negative side chamber 154 by a pressure receiving plate 123 integrally formed with the guide 122 .

Slider 124 is driven by servo valve 126 . A servo valve 126 controls the amount of intake and exhaust of the control port according to the position of the spool. Each axis air actuator 120, 130 comprises a pair of servo valves 126P, 126N respectively located on the positive and negative sides thereof. The control port of the positive side servo valve 126P communicates with the positive side chamber 152 via the positive side pipe 128P. A control port of the negative side servo valve 126N communicates with the negative side chamber 154 via a negative side pipe 128N. The position of the slider 124 is controlled by the differential pressure generated between the positive side chamber 152 and the negative side chamber 154 according to the spool positions of the servo valves 126P and 126N. Although the X-axis air actuator 120 has been described above as an example, the Y-axis air actuator 130 can be configured similarly.

FIG. 3 is a block diagram schematically showing the configuration of the control device 300 for the air actuators 120 and 130. As shown in FIG. The control device 300 includes an FB control section 310 that performs feedback control and an FF control section 360 that performs feedforward control. The calculation result u output by the output unit 302 of the control device 300 is a valve command that determines the intake/exhaust amount of the servo valves 126 and 136, and the position of the work table 110 is controlled by the differential pressure generated thereby. A position Pos _fb of the work table 110 detected by the position sensors 140 and 142 is used for feedback control in the FB control section 310 .

FF control section 360 includes three pairs of differentiators 364 , 366 , 368 and proportional compensators 370 , 372 , 374 from input section 301 to output section 302 of control device 300 . The first-stage differentiator 364 differentiates the position command Pos _ref as the drive command input from the input unit 301 and converts it into a velocity, and the first-stage proportional compensator 370 multiplies the proportional gain K _ffv to perform FB control. A speed command for the work table 110 is calculated together with the position compensation amount calculated by the unit 310 . The second-stage differentiator 366 differentiates the velocity from the differentiator ₃₆₄ and converts it into acceleration. , and an acceleration command for the work table 110 is calculated. The third-stage differentiator 368 differentiates the acceleration from the differentiator 366, and the third-stage proportional compensator 374 multiplies by the proportional gain _Kffj , and is combined with the acceleration compensation amount calculated by the FB control unit 310 to perform provisional calculation. Compute the result u'.

The FB control unit 310 is configured based on a PDD ² (Proportional-Differential-2nd Derivative) compensator. Specifically, the FB control unit 310 controls the position of the work table 110 in a major loop (outer loop) and controls the speed and acceleration of the work table 110 in a minor loop (inner loop). Of the two minor loops, the outer velocity loop is also called a mid loop, and the inner acceleration loop is simply called an inner loop. By differentiating the measured position Pos _fb of the work table 110 with the differentiator 330, the measured velocity of the work table 110 is obtained, and by differentiating it with the differentiator 332, the measured acceleration of the work table 110 is obtained.

FB control section 310 includes four subtractors 312 , 314 , 316 , and 352 in series from input section 301 to output section 302 . The subtractor 312 is a position deviation calculator that calculates a position deviation, which is the difference between the position command Pos _ref input by the input unit 301 of the control device 300 and the measured position Pos _fb of the work table 110 . The subtractor 314 is a speed deviation calculator that calculates a speed deviation, which is the difference between a speed command obtained based on a calculation described later and the measured speed of the work table 110 output by the differentiator 330 . The subtractor 316 is an acceleration deviation computing unit that computes an acceleration deviation, which is the difference between an acceleration command obtained based on a later-described computation and the measured acceleration of the work table 110 output by the differentiator 332 . The subtractor 352 is a disturbance remover that removes disturbance from the provisional calculation result u' obtained based on the calculation described later.

A position proportional compensator 320 is provided as a position compensating element for compensating the position of the work table 110 between the subtractor 312 for calculating the position deviation and the subtractor 314 for calculating the speed deviation. The position proportional compensator 320 multiplies the position deviation by the proportional gain _Kp , and together with the input from the proportional compensator 370 of the FF control unit 360 constitutes a speed command calculation unit that calculates a speed command for the work table 110 .

A velocity proportional compensator 322 is provided as a velocity compensating element for compensating the velocity of the work table 110 between the subtractor 314 that computes the velocity deviation and the subtractor 316 that computes the acceleration deviation. The speed proportional compensator 322 multiplies the speed deviation by a proportional gain _Kv , and configures an acceleration command calculation unit that calculates an acceleration command for the work table 110 in combination with the input from the proportional compensator 372 of the FF control unit 360 .

An acceleration proportional compensator 324 is provided as an acceleration compensating element for compensating the acceleration of the worktable 110 between the subtractor 316 that calculates the acceleration deviation and the subtractor 352 that removes the disturbance. The acceleration proportional compensator 324 multiplies the acceleration deviation by the proportional gain Ka, and forms _a provisional calculation section that obtains the provisional calculation result u' in combination with the input from the proportional compensator 374 of the FF control section 360 .

FB control section 310 includes notch filter 340 , disturbance observer 350 , and phase lead/lag compensation element 380 in addition to the above configuration.

Notch filter 340 is a band-stop filter having a narrow stopband centered at notch frequency ω _no , and is composed of two filter elements 340 A and 340 B provided before and after subtractor 352 . In the present embodiment, the notch frequency ω _no is set to a value close to the pipe resonance frequency ω ₀ for the purpose of removing pipe resonance. A detailed frequency allocation will be described later.

A disturbance observer 350 (DOB: Disturbance Observer) as a disturbance estimator is a state observer that estimates the disturbance to the position of the work table 110 based on the provisional calculation result u' and the measured velocity and acceleration of the work table 110. FIG. The measured quantities supplied to the disturbance observer 350 are not limited to velocity and acceleration, but may be any combination of work table 110 drive quantities including position.

Phase lead/lag compensating element 380 includes a phase lead compensating element in the numerator of the transfer function and a phase lag compensating element in the denominator of the transfer function. A transfer function of the phase lead/lag compensation element 380 is expressed by the following equation.
(ω _pd ² (s ² +2ζ _pl ω _pl s+ω _pl ² ))/(ω _pl ² (s ² +2ζ _pd ω _pd s+ω _pd ² ))
Here, both the phase lead compensating element of the numerator and the phase lag compensating element of the denominator are represented by a second-order polynomial of the variable s after Laplace transform. The second order polynomial of the phase lead compensating element includes the natural angular frequency ω _pl and the damping ratio ζ _pl . The second order polynomial of the phase lag compensating element includes the natural angular frequency ω _pd and the damping ratio ζ _pd . Since these parameters can be set independently of each other, the quadratic polynomials of the numerator phase lead compensating element and the denominator phase lag compensating element can be designed independently of each other.

FIG. 4 shows an example arrangement of various frequencies that affect the operation of controller 300 . This figure schematically shows a gain diagram representing frequency change of gain among Bode diagrams representing frequency characteristics of the control device 300 .

Bandwidth ω _b defines the frequency band in which controller 300 can operate. That is, the control device 300 is required to process signals with frequencies lower than the bandwidth _ωb . The bandwidth ω _b is generally represented by the frequency at which the gain is 3 dB lower than the low frequency region in the Bode diagram, but can be arbitrarily set according to the specifications of the control device 300 .

The resonant frequency ω ₀ is the frequency of pipe resonance. In the air actuators 120 and 130 of the present embodiment, the resonance frequency ω ₀ is positioned close to the bandwidth ω _b , and pipe resonance R occurs near the high frequency side of the operating band of the control device 300 . Since the operation of the control device 300 is adversely affected in this state, the piping resonance R is removed by the notch filter 340 described below. Incidentally, the transfer function of the pipe resonance R is represented by the following equation.
ω ₀ ² /(s ² +2ζ ₀ ω ₀ s+ω ₀ ² )
Here, the denominator is represented by a second-order polynomial of the variable s after Laplace transform, and includes the resonance frequency _ω0 as the natural angular frequency and the damping ratio _ζ0 .

The notch frequency ω _no of the notch filter 340 is set within a narrow band NB from the resonance frequency ω ₀ to less than Δω as a second predetermined value. In order to effectively remove the pipe resonance R, it is ideal to set the notch frequency ω _no to be the same as the resonance frequency ω ₀ . be done. Δω is preferably smaller than the difference ω ₀ −ω _b between the resonance frequency ω ₀ and the bandwidth ω _b , for example, Δω<(ω ₀ −ω _b )/N where N is an arbitrary natural number.

The transfer function of notch filter 340 is represented by the following equation.
(s ² +2ζ _no K _de ω _no s+ω _no ² )/(s ² +2ζ _no ω _no s+ω _no ² )
Here, both the numerator and the denominator are represented by a second-order polynomial of the variable s after Laplace transform, and include the notch frequency ω _no as the natural angular frequency and the damping ratio ζ _no . K _de contained only in the numerator is a parameter that determines the depth of the notch.

The notch filter 340 represented by the transfer function (s ² +2ζ _no K _de ω _no s+ω _no ² )/(s ² +2ζ _no ω _no s+ω _no ² ) is replaced by the transfer function ω ₀ ² /(s ² +2ζ ₀ ω ₀ s+ω ₀ ² ), the _notch frequency _{ω no} and the resonance frequency _{ω 0} ^{are approximate} values _. The term s ² +2ζ ₀ ω ₀ s+ω ₀ ² is substantially canceled (pole-zero canceled). As a result, the transfer function after application of the notch filter 340 is ω ₀ ² /(s ² +2ζ _no ω _no s+ω _no ² ). Thus, the numerator term of the notch filter 340 can substantially cancel the denominator term of the pipe resonance R, but instead leaves the second order polynomial s ² +2ζ _no ω _no s+ω _no ² in the denominator of the notch filter 340 . The notch frequency ω _no , which is the natural angular frequency, is in the vicinity of the operating band (bandwidth ω _b ) of the control device 300, like the resonance frequency ω ₀ in the second-order polynomial of the denominator of the transfer function before cancellation. Therefore, the operation of the control device 300 may continue to be hindered. A phase lead/lag compensating element 380 described below reduces this adverse effect.

Since the two terms expressed as "substantially canceled out" in the above explanation are not the same, they are not actually canceled out completely, and a certain amount of the term remains. However, since these residual terms have only a slight effect on the operation of control device 300, the following description assumes that there are no residual terms.

The natural angular frequency ω _pl included in the quadratic polynomial of the phase lead compensating element, which is the numerator term of the phase lead/lag compensating element 380, is set within a narrow band NB from the resonance frequency ω ₀ to less than Δω as the first predetermined value. be done. The natural angular frequency _ωpd included in the quadratic polynomial of the phase delay compensating element, which is the denominator term of the phase delay compensating element 380, is set to be at least _Δω higher than the resonance frequency ω0. As is clear from the figure, the difference ω _pd - ω _b between the natural angular frequency ω _pd and the bandwidth ω _b of the phase lag compensating element is greater than the difference ω ₀ - ω _b between the resonance frequency ω ₀ and the bandwidth ω _b . . That is, the natural angular frequency _ωpd is arranged on the high-frequency side farther from the bandwidth _ωb than the resonance frequency _ω0 . As will be described later, in the final transfer function of the control device 300, the phase delay compensation element s ² +2ζ _pd ω _pd s+ω _pd ² remains in the denominator, but its natural angular frequency ω _pd is sufficiently larger than the bandwidth ω _b . , the adverse effect on the operation of the control device 300 can be reduced.

The transfer function (ω _pd ² (s ² +2ζ _pl ω _pl s + ω _pl ² ))/(ω _pl ² (s ² +2 ζ _pd ω _pd s + ω _pd ² )) of the phase lead/lag compensation element 380 is applied to the notch filter 340. When applied to the subsequent transfer function ω ₀ ² /(s ² +2ζ _no ω _no s+ω _no ² ), since the natural angular frequency ω _pl and the notch frequency ω _no both within the narrow band NB are approximate values, the former The numerator term s ² +2ζ _pl ω _pl s+ω _pl ² and the latter denominator term s ² +2ζ _no ω _no s+ω _no ² are substantially canceled. Also, since the natural angular frequency ω _pl and the resonance frequency ω ₀ which are also within the narrow band NB are approximate values, the former denominator term ω _pl ² and the latter numerator term ω ₀ ² are substantially canceled. As a result, the transfer function after applying the phase lead/lag compensating element 380 is ω _pd ² /(s ² +2ζ _pd ω _pd s+ω _pd ² ), and the phase lag compensating element remains as the denominator term. However, since this natural angular frequency ω _pd is sufficiently higher than the bandwidth ω _b , it does not interfere with the operation of control device 300 .

According to the above configuration, the pipe resonance R can be removed by the notch filter 340, the remaining term (denominator term) of the notch filter 340 can also be removed by the phase lead compensation element, and finally the phase delay that does not hinder the operation of the control device 300 can be obtained. Only compensating elements can be left. Therefore, the adverse effect on the control device 300 can be reduced while removing the pipe resonance R.

FIG. 5 illustrates the effect of phase lead/lag compensation element 380. FIG.

FIG. 5A shows gain characteristics of the control device 300 before and after the improvement by the phase lead/lag compensation element 380. FIG. A curve indicated by 41 is the gain characteristic before the phase lead/lag compensating element 380 is applied, and a curve indicated by 42 is the gain characteristic after the phase lead/lag compensating element 380 is applied. In curve 41, the gain begins to decrease from frequency ω1, but in curve 42, the gain begins to decrease from frequency ω2, which is higher than frequency ω1. Thus, the phase lead/lag compensation element 380 has the effect of widening the bandwidth of the control device 300 . Comparing the manner in which the gain decreases, the slope of the curve 41 is not stable, and there are places where the gain is locally high (convex upward), whereas the curve 42 has an almost constant slope and a gentle slope. Draw a descending line. The reason for this is thought to be that phase lead/lag compensating element 380 moves the pole of control device 300 to the high band corresponding to the phase lag compensating element, thereby improving the phase lag in the low band.

In FIG. 5(B), the curve indicated by 43 is the speed command calculated by proportional compensator 370 . This figure shows the process in which the work table 110 accelerates and reaches a constant speed state. The curve labeled 44 is the position deviation (output of subtractor 312) before applying the phase lead/lag compensating element 380, and the curve labeled 45 is the position deviation after applying the phase lead/lag compensating element 380. is. Both positional deviations vibrate with the acceleration of the worktable 110, but the curve 45 after applying the phase lead/lag compensating element 380 has a smaller amplitude than the curve 44 before applying the phase lead/lag compensating element 380, and the positional deviation converges quickly. Thus, the phase lead/lag compensation element 380 has the effect of improving the responsiveness (vibration controllability) of the control device 300 .

The present invention has been described above based on the embodiments. It should be understood by those skilled in the art that the embodiments are examples, and that various modifications can be made to combinations of each component and each treatment process, and such modifications are also within the scope of the present invention.

Although the notch filter 340 for removing the pipe resonance R is provided in the embodiment, the notch filter 340 may not be provided in the present invention. In this case, the transfer function (ω _{pd 2} ^{( s 2 + 2ζ} _{pl ω pl s} ⁺ _{ω pl 2} ⁾ )/(ω _pl ² (s ² +2ζ _pd ω _pd s+ω _pd ² )) is applied, but since the resonance frequency ω ₀ and the natural angular frequency ω _pl are approximate values, the former denominator term s ² +2ζ ₀ ω ₀ s+ω ₀ ² and the latter numerator term s ² +2ζ _pl ω _pl s+ω _pl ² substantially cancel. Also, since the natural angular frequency ω _pl and the resonance frequency ω ₀ are approximate values, the former numerator term ω ₀ ² and the latter denominator term ω _pl ² are substantially canceled. As a result, the final transfer function after applying the phase lead/lag compensation element 380 is ω _pd ² /(s ² +2ζ _pd ω _pd s+ω _pd ² ), as in the embodiment. Therefore, effects similar to those of the embodiment can be obtained.

In the embodiments, in order to simplify the explanation, the case where the numerator and denominator of the transfer function are represented by a second-order polynomial has been described. It can be similarly applied to the case represented by

In the embodiment, the servo command for determining the amount of intake and exhaust of the servo valves 126 and 136 is given as an example of the working amount of the working fluid. For example, flow rate, pressure, and temperature including intake/exhaust amount may be used as operating amounts.

Although the air actuator using air as the working fluid has been described in the embodiments, the fluid actuator of the present invention may use other fluids as the working fluid. For example, a hydraulic actuator using oil as a working fluid, a hydraulic actuator using water as a working fluid, and a gas actuator using any gas other than air as a working fluid may be used. These various fluid actuators can be used for various industrial machines such as boilers and construction machines, social infrastructures such as bridges, various industrial structures such as environmental plants and water treatment facilities, and other industrial equipment.

In the embodiment, the control device 300 having the position of the work table 110 as the main control target is exemplified, but the main control target of the control device 300 may be other drive amounts such as the speed and acceleration of the work table 110 . In this case, the command value of the driving amount of the main controlled object is input to the control device 300, and the FB control is performed in the outer loop based on the deviation between it and the measured value of the driving amount.

Note that the functional configuration of each device described in the embodiments can be realized by hardware resources, software resources, or cooperation between hardware resources and software resources. Processors, ROMs, RAMs, and other LSIs can be used as hardware resources. Programs such as operating systems and applications can be used as software resources.

100 air stage, 110 work table, 120 X-axis air actuator, 122 guide, 123 pressure receiving plate, 124 slider, 126 servo valve, 128 piping, 130 Y-axis air actuator, 132 guide, 134 slider, 136 servo valve, 138 piping, 300 controller, 310 FB controller, 340 notch filter, 350 disturbance observer, 360 FF controller, 380 phase lead/lag compensation element.

Claims (5)

a driving unit that drives a driven object with a working fluid;
a control device that calculates an actuation amount of the working fluid based on an input drive command and controls the drive target;
a working fluid supply unit that supplies the working fluid based on the amount of operation calculated by the control device;
a pipe through which the working fluid flows between the drive unit and the working fluid supply unit,
The control device includes a phase lead compensating element in the numerator of the transfer function, a phase lag compensating element in the denominator of the transfer function, and a phase lead/lag compensating element used to calculate the actuation amount. a difference between a natural angular frequency of the phase lead compensation element and a frequency of pipe resonance generated when the working fluid flows through the pipe is less than a first predetermined value;
2. The fluid actuator according to claim 1, wherein the natural angular frequency of said phase lag compensating element is higher than said pipe resonance frequency by at least said first predetermined value. The control device includes, in the numerator and denominator of the transfer function, a notch frequency whose difference from the frequency of pipe resonance generated when the working fluid flows through the pipe is less than a second predetermined value, and the operation amount is calculated. with a notch filter used for
a difference between the natural angular frequency of the phase lead compensating element and the notch frequency is less than the second predetermined value;
3. The fluid actuator according to claim 1, wherein the natural angular frequency of the phase lag compensating element is higher than the notch frequency by at least the second predetermined value. a driving unit that drives a driven object with a working fluid;
a control device that calculates an actuation amount of the working fluid based on an input drive command and controls the drive target;
a working fluid supply unit that supplies the working fluid based on the amount of operation calculated by the control device;
a pipe in which the working fluid flows between the drive unit and the working fluid supply unit, and pipe resonance occurs at a frequency near the bandwidth of the control device;
The control device includes a phase lead compensating element in the numerator of the transfer function, a phase lag compensating element in the denominator of the transfer function, and a phase lead/lag compensating element used to calculate the actuation amount,
The fluid actuator, wherein the natural angular frequency of the phase lag compensating element is arranged on a higher frequency side away from the bandwidth than the natural angular frequency of the phase lead compensating element. 5. The control device according to claim 4, wherein the notch filter includes a notch frequency closer to the bandwidth than the natural angular frequency of the phase lag compensating element in the numerator and denominator of the transfer function, and is used to calculate the actuation amount. fluid actuator.

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