JPWO2009084258A1 - Motor control device - Google Patents

Abstract

It is possible to adjust the control gain quietly and safely without making the motor connected to the load vibrational. A mechanical constant identifier (121) that inputs a response V and outputs a mechanical constant during frequency response measurement, a stable boundary line calculator (122) that inputs the mechanical constant and outputs a stable boundary line during gain adjustment, and the stable An adjustment curve calculator (123) for inputting a boundary line and outputting an adjustment curve, an initial value setting unit (124) for inputting the adjustment curve and outputting a control gain initial value Kin, the adjustment curve and a control gain initial value A control gain adjuster (125) that inputs Kin and outputs a compensation amount Kf and a feedback control gain Kvj.

Description

  The present invention relates to a motor control device that adjusts a control gain and controls the operation of a motor connected to a load.

The conventional motor control device has a position proportional control gain that minimizes a position deviation evaluation function that is an error square area of a position follow-up deviation at the time of transition, and that an error square area of a torque command in a steady state does not exceed a threshold value. A speed proportional control gain is set (for example, see Patent Document 1).
FIG. 5 is a block diagram showing an example of a conventional motor control device. In FIG. 5, 501 is a target value command unit for automatic gain adjustment, 502 is a position proportional control gain, 503 is a speed proportional control gain, 504 is a torque control unit, 505 is an encoder, 506 is a motor, 507 is a ball screw mechanism, and 508. Is a position deviation evaluation function calculation unit, 509 is a position deviation evaluation function storage unit, 510 is an evaluation function minimum gain determination unit, 511 is a torque command evaluation function calculation unit, 512 is a torque command evaluation function storage unit, and 513 is a torque command determination unit. It is.
The target value command unit 501 during automatic gain adjustment outputs a position command _Xr . The position proportional control gain 502 receives the position follow-up deviation E _x obtained by subtracting the position data X _f from the position command X _r and the position proportional control gain setting value K _p , and the position follow-up deviation E _x is input to the position proportional control gain set value K _p. The speed command _Vr which is a signal amplified twice is output.
The speed proportional control gain 503 inputs a speed follow-up deviation E _v obtained by subtracting the speed data V _f from the speed command V _r and a speed proportional control gain setting value K _v and calculates a torque command T _ref . The torque control unit 504 and the torque command The result is output to the evaluation function calculation unit 511.
The torque control unit 504 receives the torque command T _ref and the encoder pulse, calculates the position data X _f and the speed data V _f , feeds back, and outputs the motor current Im to the motor 506.
The encoder 505 detects the position of the motor 506 and outputs it to the torque control unit 504 as the encoder pulse.
Motor 506 drives a ball screw mechanism 507 which is connected to the input of the motor current _{I m.}
Position deviation evaluation function calculating unit 508 outputs the position deviation evaluation function is the error square area position tracking error E _x during transient type the position tracking error E _x to the position deviation evaluation function storage 509.
The position deviation evaluation function storage unit 509 receives the position deviation evaluation function, stores the input signal, and outputs the input signal to the evaluation function minimum gain determination unit 510 as a position deviation evaluation function storage value.
The evaluation function minimum gain determination unit 510 inputs the position deviation evaluation function storage value and outputs an evaluation function minimum gain, which is a combination of control gains that minimizes the input signal, to the torque command determination unit 513.
The torque command evaluation function calculation unit 511 inputs the torque command T _ref and outputs a torque command evaluation function that is an error square area of the torque command T _ref in a steady state to the torque command evaluation function storage unit 512.
The torque command evaluation function storage unit 512 receives the torque command evaluation function, stores the input signal, and outputs it as a torque command evaluation function storage value to the torque command determination unit 513.
The torque command determination unit 513 inputs the evaluation function minimum gain and the torque command evaluation function storage value, and when the torque command evaluation function storage value does not exceed a threshold value, the evaluation function minimum gain is set as a position proportional control gain setting value Kp. Output to the position proportional control gain 502 and output to the speed proportional control gain 503 as the speed proportional control gain set value Kv.

As described above, the conventional motor control device minimizes the position deviation evaluation function, which is the error square area of the position deviation at the time of transition, and the position proportional so that the error square area of the torque command at the steady state does not exceed the threshold value. The control gain and speed proportional control gain are set.
JP-A-6-208404 (page 7, FIG. 1)

The conventional motor control device minimizes the position deviation evaluation function, which is the error square area of the position deviation at the time of transition, and the position proportional control gain and speed so that the error square area of the torque command in the steady state does not exceed the threshold value. The load connected to the motor when the control system includes an observer, filter, dead time, etc., and the stable region of the control gain that is stabilized by the control system including the control target has a complicated shape to set the proportional control gain. There has been a problem that the control gain cannot be adjusted due to the vibration of the operation or becoming unstable.
The present invention has been made in view of such a problem, and calculates the stable region of the control gain and adjusts the control gain within the stable region, so that the operation of the load connected to the motor becomes oscillatory. It is an object of the present invention to provide a motor control device capable of adjusting a control gain quietly in a short time without becoming unstable.

In order to solve the above problem, the present invention is configured as follows.
According to the first aspect of the present invention, there is provided a feedback controller that calculates a torque command (T _α ) before disturbance compensation by performing a control calculation so that a command (V _r ) and a response (V) to be controlled match, and the disturbance Disturbance for calculating the estimated disturbance value (T _d ) based on the torque command (T _ref ), which is a value obtained by subtracting the estimated disturbance value (T _d ) from the pre-compensation torque command (T _α ), and the response (V). and the observer, the frequency response measurement signal (F _r) and a torque command to (T _ref) input the frequency response measurement signal at the frequency response measurement and (F _r), the torque command at the time of gain adjust (T _ref) an input signal switch for outputting a current command (I _r), and the current command torque controller which drives by supplying a motor current (I _m) to the motor of the control object on the basis of (I _r), the response ( V) and And a torque command (T _ref) and the basis vibration suppression unit for calculating a vibration suppressing signal (V _s), in a motor control device for adding the vibration suppression signal to said command _{(V r) (V s)} , A control gain adjustment unit that calculates the feedback control gain (K _vj ) and the correction amount (K _f ) of the feedback controller based on the response (V) is provided.

The invention according to claim 2 is the invention according to claim 1, wherein the frequency response measurement signal (F _r ) is a swept sine wave signal.
According to a third aspect of the present invention, in the first aspect of the present invention, the frequency response measurement signal (F _r ) is composed of a sine wave having a plurality of frequencies.

According to a fourth aspect of the present invention, in the first aspect of the invention, the control gain adjusting unit identifies a mechanical constant of the control target based on the response (V) at the time of frequency response measurement. And the feedback control gain that stabilizes the closed loop system including the feedback controller and the controlled object, and the stable boundary line that is the outline of the stable region of the compensation amount (K _f ), based on the mechanical constant And the feedback control gain and the compensation amount (K _f) so as to enhance the response and disturbance suppression characteristics of the closed loop system while maintaining the stability of the control target based on the stable boundary line. ) adjustment curve calculator for calculating an adjustment curve can be adjusted, the feedback control gain (K _vj) and before the control gain adjustment based on the adjustment curve Compensation amount (K _f) the initial value at which the control gain initial value (K _in) and the initial value setting unit for calculating a, the adjustment curve and the control gain initial value (K _in) the feedback control gain based on the (K _vj ) and a compensation gain adjuster for adjusting the compensation amount (K _f ).

  The invention according to claim 5 is the invention according to claim 4, wherein the mechanical constant identifier calculates a frequency response of the controlled object, and calculates the mechanical constant based on the frequency response. To do.

The invention according to claim 6 is the invention according to claim 4, wherein the stable boundary line calculator calculates an equivalent unit feedback system of the closed loop system based on the mechanical constant, and The stable boundary line is calculated so that the phase margin becomes a positive phase margin setting value.
According to a seventh aspect of the present invention, in the sixth aspect of the invention, the phase margin setting value allows the uncertainty when the mechanical constant is uncertain, so that the closed loop system becomes stable. It is characterized by setting to a different value.

According to an eighth aspect of the present invention, in the invention according to the fourth aspect of the present invention, when the adjustment curve computing unit has one stable curve, the compensation amount (K _f ) is zero and the feedback control gain (K _vj ) is output as a straight line such that the compensation amount (K _f ) of the stable curve increases toward the optimum control gain value at which the compensation amount (K _f ) becomes zero, and when there are two stable curves, 2 A curve that passes through the middle of the two stability curves and is directed to the control gain optimum value that is the intersection of the two stability curves is output as the adjustment curve.

The invention according to claim 9 is the invention according to claim 8, wherein the initial value setter is configured to provide the feedback control gain at a point separated from the optimum value of the control gain at a point on the adjustment curve. (K _vj ) and the compensation amount (K _f ) are output as the control gain initial value (K _in ).
The invention according to claim 10 is the invention according to claim 9, wherein the control gain adjuster is configured to move the control gain initial value (K _in ) from the control gain initial value (K _in ) toward the control gain optimum value along the adjustment curve. The feedback control gain (K _vj ) and the compensation amount (K _f ) are increased and output.

According to the first to seventh aspects of the present invention, the stable region of the control gain can be calculated and the control gain can be adjusted within the stable region, so that the control gain can be adjusted quietly and safely without making the controlled object vibrational. It can also achieve high control performance automatically.
Further, according to the invention described in claims 8 to 10, the control gain is adjusted from the control gain initial value close to the optimal value of the control gain on the adjustment curve on which the vibration hardly occurs in the stable region. The control gain can be adjusted quietly, safely and in a short time, and high control performance can be realized automatically.

The block diagram which shows the outline | summary of the motor control apparatus of 1st Example of this invention. The figure which shows the equivalent unit feedback system of the motor control apparatus of FIG. 1 which shows 1st Example of this invention. The figure showing the Bode diagram and Nyquist diagram of the open loop system in the simulation which shows 1st Example of this invention The figure showing the stable boundary line, adjustment curve, and control gain initial value in the simulation which shows 1st Example of this invention Block diagram showing an example of a conventional motor control device

Explanation of symbols

DESCRIPTION OF SYMBOLS 101 Command generator 102 Feedback controller 103 Input signal switch 104 Torque controller 105 Control object 106 Response detector 107 Disturbance observer 108 Frequency response measurement signal generator 110 Vibration suppression part 111 Vibration component calculator 112 Phase adjuster 113 Compensation Quantity adjuster 120 Control gain adjuster 121 Mechanical constant identifier 122 Stable boundary line calculator 123 Adjustment curve calculator 124 Initial value setter 125 Control gain adjuster 201 Open loop transfer function 501 Target value command unit 502 during automatic gain adjustment Proportional control gain 503 Speed proportional control gain 504 Torque control unit 505 Encoder 506 Motor 507 Ball screw mechanism 508 Position deviation evaluation function calculation unit 509 Position deviation evaluation function storage unit 510 Evaluation function minimum gain determination unit 511 Torque command evaluation function calculation unit 51 Torque command evaluation function storage unit 513 torque command determination unit

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
Although various functions and means are built in the actual motor control device, only the functions and means related to the present invention will be described and described in the figure. Hereinafter, the same reference numerals are assigned to the same names as much as possible, and the duplicate description is omitted.

  FIG. 1 is a block diagram showing an outline of a motor control device according to a first embodiment of the present invention. In FIG. 1, 101 is a command generator, 102 is a feedback controller, 103 is an input signal switch, 104 is a torque controller, 105 is a control target, 106 is a response detector, 107 is a disturbance observer, and 108 is a frequency response measurement. 110 is a vibration suppression unit, 120 is a control gain adjustment unit, 111 is a vibration component calculator, 112 is a phase adjuster, 113 is a compensation amount adjuster, 121 is a machine constant identifier, and 122 is stable. The boundary line calculator, 123 is an adjustment curve calculator, 124 is an initial value setter, and 125 is a control gain adjuster.

The control target 105 is a motor connected with a load.
The command generator 101 outputs a command _Vr .
The response detector 106 detects the response of the control target 105 and outputs a response V.
The frequency response measurement signal generator 108 outputs a frequency response measurement signal Fr.
The feedback controller 102 calculates the pre-disturbance compensation torque command T _α by inputting the vibration suppression tracking deviation obtained by subtracting the response V from the command V _r and adding the vibration suppression signal V _s and the feedback control gain K _vj .
The input signal switch 103 receives a torque command T _ref obtained by subtracting the estimated disturbance value T _d from the pre-disturbance compensation torque command T _α and a frequency response measurement signal F _r , and the torque command T _ref is a current command when adjusting the gain. as I _r, the time frequency response measurement input signal Fr for frequency response as the current command I _r, and outputs the torque controller 104.
Torque controller 104 receives the current command _{I r,} drives the motor of the controlled object 105 by passing a motor current _{I m.}
The disturbance observer 107 receives the torque command T _ref and the response V during gain adjustment, and calculates a disturbance estimated value T _d .

The vibration suppression unit 110 includes a vibration component calculator 111, a phase adjuster 112, and a compensation amount adjuster 113, and inputs a torque command T _ref , a response V, and a compensation amount K _f at the time of gain adjustment. A suppression signal V _s is calculated.
The vibration component calculator 111 receives the torque command T _ref and the response V, calculates the vibration component of the response V, and outputs it to the phase adjuster 112.
The phase adjuster 112 receives the vibration component, calculates a phase adjustment vibration component obtained by adjusting the phase of the input signal, and outputs the calculated phase adjustment vibration component to the compensation amount adjuster 113.
Compensation amount adjuster 113 calculates the phase adjustment vibration component and the compensation amount K _f enter the phase adjustment vibration component in the compensation amount K _f vibration suppression signal V _s obtained by multiplying the.

The control gain adjustment unit 120 includes a machine constant identifier 121, a stable boundary line calculator 122, an adjustment curve calculator 123, an initial value setter 124, and a control gain adjuster 125. During frequency response measurement, The response V is input, and the compensation amount _Kf and the feedback control gain are calculated at the time of gain adjustment.
The machine constant identifier 121 receives the response V at the time of frequency response measurement, calculates the machine constant of the controlled object 105, and outputs it to the stable boundary line calculator 122.
Specifically, the mechanical constant identifier 121 calculates a frequency response (Bode diagram) based on the response V, calculates an anti-resonance frequency and a resonance frequency from a frequency and a frequency at which a peak occurs in the amplitude diagram, and the groove The anti-resonance damping coefficient and the resonance damping coefficient are calculated from the peak Q value and the moment of inertia of the controlled object 105 based on the value of the amplitude diagram at a frequency sufficiently lower than the lowest of the anti-resonance frequencies. And the antiresonance frequency, the resonance frequency, the damping coefficient, and the moment of inertia are used as the mechanical constant.

The stable boundary line calculator 122 inputs the mechanical constant at the time of gain adjustment, and a feedback control gain K _vj that makes the closed loop system including the feedback controller 102, the control target 105, the response detector 106, and the disturbance observer 107 critically stable. and it calculates the curve a is the stability boundary line of a combination of the compensation amount K _f, and outputs the adjusted curve calculator 123.
The adjustment curve calculator 123 receives the stable boundary line during gain adjustment, and provides a feedback control gain K _vj and a compensation amount K _f so that the response V does not vibrate within the stable region surrounded by the stable boundary line. An adjustment curve consisting of a combination of the above is calculated and output to the initial value setting unit 124 and the control gain adjustment unit 125.
The initial value setter 124 inputs the adjustment curve at the time of gain adjustment, and sets a point that is on the adjustment curve and is sufficiently close to the optimal control gain point that is the point at which the response V is optimal during normal operation. _It is calculated as in and output to the control gain adjuster 125.
The control gain adjuster 125 inputs the adjustment curve and the control gain initial value K _in at the time of gain adjustment, and a compensation amount K _f from the control gain initial value K _in along the adjustment curve toward the optimum control gain point. The feedback control gain K _vj is changed, and the compensation amount K _f is output to the compensation amount adjuster 113 and the feedback control gain K _vj is output to the feedback controller 102.

The frequency response measurement signal F _r may be any signal as long as it can measure the frequency response of the motor control device, but is preferably a swept sine wave signal. Further, it may be composed of sine waves having a plurality of frequencies. By using the frequency response measurement signal _Fr as a swept sine wave signal, the frequency response of the controlled object 105 can be accurately measured in a short time. In addition, by setting the frequency response measurement signal _Fr to a sine wave having a plurality of frequencies, the frequency response of the control target 105 can be measured accurately in a short time.

The present invention is different from the prior art in that a mechanical constant identifier 121 that inputs a response and outputs a mechanical constant at the time of frequency response measurement, and a stable boundary line calculator that inputs the mechanical constant and outputs a stable boundary line at the time of gain adjustment. and 122, the an adjustment curve calculator 123 for outputting the inputted adjustment curve stability boundary line, the initial value setting unit 124 for outputting the inputted adjustment curve control gain initial value K _in, the control gain with the adjustment curve the control gain adjuster 125 for outputting the inputted initial value _{K in} the compensation amount _{K f} and the feedback control gain _{K vj,} a portion comprising a.

Hereinafter, the details of how the control gain adjustment unit 120 calculates the compensation amount K _f and the feedback control gain K _vj.
In this embodiment, it is assumed that the feedback controller 102 is coupled in series with a speed PI controller and a torque command filter that is a first-order low-pass filter, and the control target 105 includes a notch filter, a dead time, and a three-inertia mechanism. .
The command V _r is a speed command, and the response V is a motor speed (hereinafter referred to as “motor speed V”).
Speed PI controller transfer function _G c (s), the torque command filter transfer function _G t (s), transmission of a notch filter function _G n (s), 3 inertial mechanical transfer function _G p (s), and, The transfer function G _b (s) of the phase adjuster 112 that is a bandpass filter is expressed by Expressions (1) to (5), respectively.

_{However, K vj} speed proportional control gain, _{T i} is the time constant velocity control integration.

Although the speed proportional control gain K _vj and the speed control integration time constant T _i are feedback control gains, it is well known that when the speed proportional control gain K _vj is determined, the speed control integration time constant T _i is dependently determined. Therefore, in this embodiment, only a method for obtaining the speed proportional control gain K _vj as the feedback control gain is described.

However, the tau _f is time constant torque command filter.

Here, ω _n is the notch filter frequency, and ζ _n is the attenuation coefficient of the notch filter.

Where J is the total moment of inertia of the three inertia mechanism, ω _r1 is the first resonance frequency, ζ _r1 is the first resonance damping coefficient, ω _a1 is the first anti-resonance frequency, and ζ _a1 is the first anti-resonance damping coefficient, ω _r2 is the second resonance frequency, ζ _r2 is the attenuation coefficient of the second resonance, ω _a2 is the second anti-resonance frequency, and ζ _a2 is the attenuation coefficient of the second anti-resonance.

Where τ is a bandpass filter time constant.

  The disturbance observer 107 estimates a part of the constant of the control target 105 that is not accurately known, and disturbance due to gravity disturbance or noise. The transfer function of the disturbance observer 107 is expressed by equation (6).

Where T _d ^* is the Laplace transform of the estimated disturbance value T _d , J ₀ is the nominal moment of inertia, D ^* is the Laplace transform of the normalized estimated disturbance D, V ^* is the Laplace transform of the motor speed V, and T _ref ^* is the controlled object 105 is a Laplace transform of a torque command T _ref for generating torque for driving the motor constituting the motor 105, G _vd (s) is a transfer function from the motor speed V ^* to the estimated disturbance value T _d ^* , and l ₁ and l ₂ are The disturbance observer gain, G _td (s), is a transfer function from the torque command T _ref ^* to the disturbance estimated value T _d ^* .

  The vibration component calculator 111 calculates the motor speed from which the vibration component has been removed by the speed observer represented by the equation (7), and subtracts the motor speed from which the vibration component has been removed from the motor speed V. The vibration component contained in is calculated.

Where V _e ^* is the Laplace transform of the estimated motor speed V _e , G _tv (s) is the transfer function from the torque command T _ref ^* to the estimated motor speed V _e ^* , l is the speed observer gain, and G _vv (s) is It is a transfer function from the motor speed V ^* to the estimated motor speed V _e ^* .

The phase adjuster 112 is composed of a bandpass filter represented by Expression (5), and calculates the phase adjusted vibration component that is changed so that the phase of the input vibration component matches the phase of the command V _r .

FIG. 2 is a diagram showing an equivalent unit feedback system of the motor control device of FIG. 1 showing the first embodiment of the present invention. In FIG. 2, 201 is an open loop transfer function.
FIG. 2 is obtained by equivalently converting the part excluding the control gain adjusting unit 120 from FIG. 1 into a unit feedback system.
The open-loop transfer function 201 is expressed by using the dead time T _L , the first rational transfer function G ₁ (s) shown in Expression (8), and the second rational transfer function G ₂ (s) shown in Expression (9). It is represented by (10).

However, _Kf is the compensation amount in FIG.

  In order to calculate the stable boundary line by the stable boundary line calculator 122, the open loop transfer function 201 of FIG. 2 is approximated as shown in Expression (10).

However, N _olv , D _ol0 , and D _olv are polynomials of a Laplace variable s independent of the speed proportional control gain K _vj and the compensation amount K _f , and Padé approximation is used for approximation from the irrational transfer function to the rational transfer function.

The stable region where the closed loop system is stable in the (K _vj , K _f ) plane is obtained from the condition that the phase margin of the open loop transfer function 201 is positive in the unit feedback system.
Substituting s = jω into equation (10) to obtain the phase margin condition yields equation (11). However, j is an imaginary unit.

However, N _r , N _i , D _0r , D _vr , D _0i , and D _vi are polynomials relating to s independent of the speed proportional control gain K _vj and the compensation amount K _f .

Equation (12) holds because the gain crossover frequency omega _c is the amplitude of the open-loop transfer function 201 is one.

  Equation (12) is transformed to obtain equation (13).

When the value of K _vj · K _f is determined, K _vj can be obtained using equation (13).

  Next, the condition that the phase margin of the open loop transfer function 201 is δ is expressed by Expression (14).

Gain crossover frequency ω phase of the open loop transfer function 201 in _c is expressed by Equation (15).

Substituting equation (15) into equation (14) and solving for K _f · K _vj yields equation (16).

When the gain crossover frequency ω _c is determined, K _f · K _vj is obtained from the equation (16).
K _f · _K A value of _vj into equation (13) _{K vj} is _{determined, K f} is determined by dividing the K f · _{K vj} in _{K vj.}
In this way, the stable boundary line that makes the closed loop system of FIG. 1 stable with a phase margin δ (K _vj , K _f ) is obtained.
When the stable boundary line is composed of two curves, the optimum gain set in which the closed loop system of FIG. 1 is stable and the bandwidth is large (K _vj , K _f ) is the intersection of the two curves.
On the other hand, when the stable boundary line is composed of one curve, the optimum gain set is a point where K _f = 0 in the one curve.

Adjustment curve calculator 123, if the stability curves of one compensation amount K _f is zero, the compensation amount K _f of the feedback control gain is the stability curves toward the control gain optimum value is that the zero An increasing straight line is output as the adjustment curve, and when there are two stability curves, a curve that passes through the middle of the two stability curves and reaches the optimum control gain value that is the intersection of the two stability curves is the adjustment curve. Output as.
The initial value setting unit 124 outputs the feedback control gain and the compensation amount _Kf as the control gain initial value K _{in at} a point separated from the control gain optimum value at a point on the adjustment curve.
Thus, by setting the adjustment curve, it is possible to quietly and safely adjust (K _vj , K _f ) to the optimum gain set without causing the closed loop system of FIG. 1 to vibrate.
Control gain adjuster 125, controls the gain initial value the optimum gain set in towards the control gain set is the intersection of the stability boundary line along the adjustment line from _{K in (K vj, K f} ) adjusting. Control gain set _(K vj, K _f) along the adjustment curve closer to the optimum gain set, the control gain set to be the highest value _{K vj} range response V does not oscillate _(K vj, K _f) The optimum value is used.
Compensation amount adjuster 113 multiplies the amount of compensation K _f to the phase adjustment vibration component calculates the vibration suppression signal V _s.
In the gain adjustment of the present invention, by adjusting (K _vj , K _f ) along the adjustment curve from the control gain initial value toward the optimum gain set, the closed loop system can be shortened without making it vibrate. The optimum gain set can be adjusted quietly and safely in time.

In this embodiment, the feedback controller 102 is a speed PI controller. However, the speed P controller, the speed IP controller, the position P speed PI controller, the position P speed IP controller, the position The present invention can be similarly applied to an arbitrary controller such as a PID controller.
Further, the present invention can be similarly applied regardless of the torque command filter, notch filter, disturbance observer, presence / absence of dead time, and the number of dead times.

  In addition, the present invention can be applied to the control object 105 for a rigid body mechanism and an arbitrary multi-inertia mechanism similarly to the present embodiment.

Further, in order to lower the orders of the equations (13) and (16), G _n (s) · G _p (s) is approximated as in the equation (17), and the stable boundary line is obtained in the same manner. (K _vj , K _f ) can be automatically adjusted.

Hereafter, the simulation result of a present Example is shown. The numerical values used in the simulation are as follows.
J = 1.51 × 10 ⁻⁴ [kg · m ² ],
ω _r1 = 295 × 2 × π [rad / s], ζ _r1 = 0.16,
ω _a1 = 128 × 2 × π [rad / s], ζ _a1 = 0.16,
ω _r2 = 1340 × 2 × π [rad / s], ζ _r2 = 0.05,
ω _a2 = 906 × 2 × π [rad / s], ζ _a2 = 0.05, n _d = 10,
s ₀ = 50 × 2 × π [rad / s], l ₁ = 6.28 × 10 ² ,
l ₂ = 9.87 × 10 ⁴ , Kv = 60 × 2 × π [s ⁻¹ ],
J ₀ = 1.51 × 10 ⁻⁴ [kg · m ² ],
K _vj = Kv × J = 0.0569 [N · m · s / rad], T _i = 4 / Kv = 0.0085 [s], τ _f = 1 / (4 × Kv) = 0.44 × 10 ^-3 [s],
ω _n = ω _r2 = 1340 × 2 × π [rad / s], ζ _n = 0.7,
Trat = 0.637 [N · m], T = 125 × 10 ⁻⁶ [s],
T _t = 250 × 10 ⁻⁶ [s]
Where n _d is the order of the Padé approximation used in equation (10), s ₀ is the pole of the velocity observer, l ₁ and l ₂ are disturbance observer gains such that the pole is s _0, and K _v is the normalized velocity proportional control. The gain, T _rat is the rated torque, T is the control period, and _{TL is the} dead time. The nominal moment of inertia J ₀ is a value of moment of inertia used for the disturbance observer 107 and the vibration component calculator 111.

The speed proportional control gain K _vj , the speed control integral time constant T _i and the torque command filter time constant τ _f are set dependently using the normalized speed proportional control gain K _v as described above.
As described above, the model used for this simulation is shown in FIG. 1. In FIG. 1, the feedback controller 102 is a speed PI controller expressed by equation (1) and a torque command filter expressed by equation (2), and the torque controller 104 is expressed by equation (3). The control object 105 is represented by equation (4), and the vibration component calculator 111 subtracts the estimated velocity value V ^* calculated by the velocity observer of equation (7) from the response V to calculate the vibration component. And the phase adjuster 112 is a bandpass filter of equation (5), and the disturbance observer 107 is of equation (6). However, the expression (4) representing the controlled object 105 is expressed in discrete time of the control cycle T, and the torque command T _ref is saturated at the rated torque T _rat .

FIG. 3 is a diagram showing a Bode diagram and a Nyquist diagram of an open loop system in the simulation showing the first embodiment of the present invention.
FIG. 3A is a Bode diagram of the open loop transfer function 201 of FIG. In FIG. 3A, the solid line is a Bode diagram based on the three-inertia system model of Equations (3) and (4), and the alternate long and short dash line is the Bode diagram based on the two-inertia approximation model of Equation (17). It is.
3 from (a), the other around the second reaction resonance frequency omega _a2, the 3-inertia system Bode diagram based on the model substantially coincides with the Bode diagram based on the 2-mass approximation model.
In FIG. 3A, it can be seen from the phase diagram that a, b, and c are frequencies at which the amplitude is 1, and the frequency having the smallest phase margin is the point c.
FIG. 3B is a Nyquist diagram of the open loop system. In FIG. 3B, the solid line is a Nyquist diagram based on the three-inertia system model, the alternate long and short dash line is a Nyquist diagram based on the two-inertia approximation model, and the broken line is a unit circle.
In FIG. 3B, a, b, and c indicate points where the Nyquist diagram intersects the unit circle, respectively, and correspond to a, b, and c in FIG. It can be seen from FIG. 3B that point c is closest to the second quadrant and has the greatest influence on the stability of the unit feedback system of FIG.

Varying the normalized speed proportional control gain K _v, the phase diagram of FIG. 3 (a) hardly changes, only the amplitude view changes approximately in proportion to the amount of change in normalized speed proportional control gain K _v.
The frequency of vibration that occurs when the normalized speed proportional control gain _Kv is increased substantially matches the phase crossover frequency that is the frequency at which the phase diagram is -180 degrees.
Stable boundary calculator 122 first draw the Bode diagram shown in FIG. 3 (a) by setting an appropriate value to the speed proportional control gain K _v, determined the phase crossover frequency, suppressing the vibration suppressing unit 110 and suppressing vibration frequency ω _v.
Next, determine the value of the normalized speed proportional control amplitude such that slightly less than 1 in the phase crossover frequency gain K _v.
The bandpass filter time constant τ, disturbance observer gains l ₁ and l ₂ , and observer gain l are set as follows.
l ₁ = ω _v / 2, l ₂ = ω _v / 2, l = ω _v / 2, τ = 2 / ω _v
Based on the above set values, the stable boundary line calculator 122 calculates the stable boundary line.
The stable boundary line calculator 122 calculates a closed-loop equivalent unit feedback system including the feedback controller 102 and the control target 105 based on the machine constant, and a phase margin setting in which the phase margin of the equivalent unit feedback system is a positive number. The stable boundary line is calculated to be a value.
The phase margin set value is set to a value that allows the uncertainty when the machine constant is uncertain and stabilizes the closed-loop system.

FIG. 4 is a diagram showing a stable boundary line, an adjustment curve, and an initial control gain value in the simulation showing the first embodiment of the present invention. In FIG. 4, a solid line indicates a stable boundary line, a broken line indicates an adjustment curve, x indicates a control gain initial value, and □ indicates a stable region.
In this simulation, the phase margin δ was set to 0 degree.
As shown in FIG. 4, the stability boundary line operator 122 outputs the stability boundary line, adjustment curve calculator 123 outputs the adjustment curve, the initial value setting unit 124 sets the control gain initial value K _in The control gain adjuster 125 adjusts the control gain set (K _vj , K _f ) from the control gain initial value K _in toward the optimum gain set that is the intersection of the stable boundary lines along the adjustment curve.

  If the machine constant output from the machine constant identifier 121 is inaccurate, setting the phase margin δ to a value larger than 0 degrees narrows the stable region of FIG. 4 and reduces the inaccuracy of the machine constant. The gain can be adjusted quietly and safely without making the closed loop system of FIG. 1 oscillating.

Further, when the control target 105 is an arbitrary multi-inertia system, the closed loop system of FIG. 1 does not include a disturbance observer, regardless of the presence or number of notch filters and low-pass filters, and the control law of the feedback controller 102. However, the present invention can be applied in the same manner as the present embodiment.
That is, the present invention is also applied to the case where the feedback controller is speed P control, speed IP control, position P speed P control, position P speed PI control, position P speed IP control, position PID control, etc. It can be applied in the same way.

  As described above, the control gain stable region is calculated based on the machine constant of the controlled object, so that the controlled gain can be adjusted quietly and safely without making the controlled object oscillating, and automatically high. Control performance can be realized.

  Since the control gain can be adjusted quietly and safely without making the motor connected to the load vibrational, it can be widely applied to general industrial equipment such as semiconductor manufacturing equipment, liquid crystal panel manufacturing equipment, machine tools, and industrial robots.

Claims (10)

A feedback controller for calculating a torque command (T _α ) before disturbance compensation by performing a control calculation so that the command (V _r ) and the response (V) of the controlled object match;
The estimated disturbance value (T _d ) is calculated based on the torque command (T _ref ), which is a value obtained by subtracting the estimated disturbance value (T _d ) from the pre-disturbance torque command (T _α ), and the response (V). A disturbance observer,
Frequency response measurement signal (F _r) and a torque command to (T _ref) and inputs the frequency response measurement signal at the frequency response measurement (F _r), the current command and the torque command (T _ref) at the time of gain adjustment ( An input signal switcher that outputs as I _r ),
A torque controller that drives the motor to be controlled by passing a motor current (I _m ) based on the current command (I _r );
A vibration suppression unit that calculates a vibration suppression signal (V _s ) based on the response (V) and the torque command (T _ref ), and adds the vibration suppression signal (V _s ) to the command (V _r ). In the motor control device
A motor control apparatus comprising: a control gain adjustment unit that calculates a feedback control gain (K _vj ) and the correction amount (K _f ) of the feedback controller based on the response (V). The motor control device according to claim 1, wherein the frequency response measurement signal (F _r ) is a swept sine wave signal. The motor control device according to claim 1, wherein the frequency response measurement signal (F _r ) includes a sine wave having a plurality of frequencies. The control gain adjusting unit is configured to identify a machine constant to be controlled based on the response (V) at the time of frequency response measurement.
Based on the mechanical constant, the feedback control gain for stabilizing the closed loop system including the feedback controller and the control target, and a stable boundary line that is an outline of a stable region of the compensation amount (K _f ) are calculated. A boundary line calculator,
Based on the stable boundary line, an adjustment curve capable of adjusting the feedback control gain and the compensation amount (K _f ) so as to improve the response and disturbance suppression characteristics of the closed loop system while maintaining the stability of the control target is calculated. An adjustment curve calculator,
An initial value setter that calculates a control gain initial value (K _in ) that is an initial value of the feedback control gain (K _vj ) and the compensation amount (K _f ) in control gain adjustment based on the adjustment curve;
A control gain adjuster that adjusts the feedback control gain (K _vj ) and the compensation amount (K _f ) based on the adjustment curve and the control gain initial value (K _in ). The motor control device according to claim 1.   The motor control device according to claim 4, wherein the mechanical constant identifier calculates a frequency response of the control target and calculates the mechanical constant based on the frequency response.   The stable boundary line computing unit calculates an equivalent unit feedback system of the closed loop system based on the mechanical constant, and the stable boundary line so that the phase margin of the equivalent unit feedback system becomes a positive phase margin set value. The motor control device according to claim 4, wherein the motor control device is calculated.   7. The motor control according to claim 6, wherein the phase margin setting value is set to a value that allows the uncertainty when the mechanical constant is uncertain and makes the closed loop system stable. apparatus. In the adjustment curve calculator, when there is one stable curve, the compensation amount (K _f ) is zero, and the feedback control gain (K _vj ) is zero for the compensation amount (K _f ) of the stable curve. A straight line that increases toward the optimal control gain value as a point is output as the adjustment curve, and when there are two stable curves, the control is the intersection of the two stable curves through the middle of the two stable curves. The motor control device according to claim 4, wherein a curve toward an optimum gain value is output as the adjustment curve. The initial value setting unit calculates the feedback control gain (K _vj ) and the compensation amount (K _f ) at the point separated from the optimal value of the control gain at the point on the adjustment curve by the initial value of the control gain. The motor control device according to claim 8, wherein the motor control device outputs as (K _in ). The control gain adjuster increases the feedback control gain (K _vj ) and the compensation amount (K _f ) from the control gain initial value (K _in ) toward the control gain optimum value along the adjustment curve. The motor control device according to claim 9, wherein the motor control device outputs the motor control device.