JP2006074896A - Motor control device - Google Patents

Abstract

Provided is a motor control device that can adjust control parameters easily and accurately, and does not vibrate and has high response and high accuracy.
An inertia total value J obtained by adding a value obtained by converting a rotor inertia value of a motor and an inertia value of a load machine driven by the motor into a rotation shaft of the motor, and a viscous friction coefficient D are set as a torque command. The relational expression from T _ref to the motor speed detection signal V _fb is multiplied by the time differential value V _fb ′ of the motor speed detection signal to integrate the time, and the relational expression from the torque command T _ref to the motor speed detection signal V _{fb is} expressed as time. A control constant identification unit is provided for converting and calculating a time-integrated expression by multiplying the differentiated expression by the time differential value V _fb ′ of the motor speed detection signal.
[Selection] Figure 1

Description

  The present invention relates to an inertia identification technique and a viscous friction coefficient identification technique in a case where there is an inertia change during operation in a motor control device that drives a robot, a machine tool, or the like.

  Some conventional motor control devices have a function of identifying inertia (see, for example, Patent Document 1).

FIG. 4 is a block diagram of a motor control device having an inertia identification function in Patent Document 1. In FIG. In FIG. 4, 51 is a speed command generation part, and outputs speed command _Vref . 52 is a speed control unit, determines a torque command so that the actual motor speed V _fb and the speed command V _ref coincide, to control the motor speed V _fb. An estimation unit 53 simulates the speed control unit 52 so that the motor speed V _fb matches the model speed V _fb . Reference numeral 54 denotes an identification unit, which is a value obtained by integrating the absolute value of the value obtained by passing a predetermined filter into the speed deviation V _e of the speed control unit 52 over a predetermined period, and the absolute value of the speed deviation V _e of the estimation unit 53. Inertia is identified from the ratio to the value obtained by integrating the time in the same interval. Only when the speed deviation V _e ˜ of the estimation unit 53 is zero and the speed V _fb of the model in the estimation unit 53 is not zero, the identification unit 54 performs an operation for identifying the inertia. is there.

In this motor control device, inertia can be identified in real time for an arbitrary speed command, so that inertia can be identified even when the inertia changes from moment to moment.
Japanese Patent No. 3185857

  However, in the conventional motor control device, if the viscous friction is large, or if there is a constant disturbance such as gravity or Coulomb friction, the inertia identification value is greatly calculated due to the influence, so control is performed using the identified inertia value. When the parameters are adjusted, there is a problem that the vibration is caused.

  The present invention has been made in view of such problems. Even when viscous friction is large, or when there is constant disturbance such as gravity or Coulomb friction, the inertia is accurately identified, and the viscous friction coefficient is also identified. It is an object of the present invention to provide a motor control device that can easily and accurately adjust control parameters and realize a high-speed, high-accuracy, low-vibration response.

The present invention according to claim 1, a speed command generation unit for generating a speed command V _ref, a speed control unit for generating a torque command T _ref as the speed command V _ref and the motor speed detection signal V _fb coincides, In a motor control device including a torque control unit that generates a motor drive current from a torque command T _ref and a detector that detects a position or speed of the motor and generates a motor speed detection signal V _fb , a motor rotor inertia From the torque command T _ref to the motor speed detection signal V _fb, the inertia total value J, which is the sum of the value and the inertia value of the load machine driven by the motor, converted into the rotation axis of the motor, and the viscous friction coefficient D wherein the torque command T _ref from the motor speed detection signal V _f which is multiplied by the time of the motor speed detection signal to equation differential value V _{fb 'and} integration time It is obtained as a control constant identifying unit that calculates and converts the expressions to time integral is multiplied by the time-differentiated value V _{fb 'of} the motor speed detection signal relation to the time obtained by differentiating the equation up.

In the present invention described in claim 2, the position controller that generates the speed command V _ref so that the position command P _ref and the motor position detection signal P _fb match, the speed command V _ref and the motor speed detection signal V _fb are A speed control unit that generates a torque command T _ref so as to match, a torque control unit that generates a motor drive current from the torque command T _ref , and a detection that detects the position or speed of the motor and outputs a motor speed detection signal V _fb Motor inertial motor, and inertia total value J, which is a sum of values obtained by converting the rotor inertia value of the motor and the inertia value of the load machine driven by the motor to the rotation axis of the motor, and the viscous friction coefficient and D, the time is multiplied by the time-differentiated value V _{fb 'of} the motor speed detection signal relationship from the torque command T _ref until the motor speed detection signal V _fb Calculated by converting the divided-mentioned formula and the torque command T _ref the relationship to the motor speed detection signal V _fb to the time integral is multiplied by the time-differentiated value V _{fb 'time} obtained by differentiating the motor speed detection signal to the formula from the formula A control constant identification unit is provided.

  According to a third aspect of the present invention, in the motor control device according to the first or second aspect, the control constant identification unit calculates the inertia total value J and the viscous friction coefficient D,

... (1)

... (2)

_{However, T ref} 'is _T time derivative of _{ref, V fb'} is _V time derivative of _fb, a and b represent arbitrary time b> a
It is made to calculate by.

According to a fourth aspect of the present invention, in the motor control device according to the first or second aspect, the control constant identifying unit defines the interval [a, b] for calculating the inertia total value J as the motor speed at the time a. A section in which the absolute value | V _fb (a) | and the absolute value of the motor speed | V _fb (b) | at time b coincide with each other, and the inertia total value J and the viscous friction coefficient D are

... (3)

... (4)

It is made to calculate by.

According to a fifth aspect of the present invention, in the motor control device according to the first or second aspect, the control constant identifying unit defines an interval [a, b] for calculating the inertia total value J as a speed differential of the motor at time a. Between the absolute value | V _fb ′ (a) | and the absolute value | V _fb ′ (b) | of the motor speed differential at time b, and the inertia total value J and the viscous friction coefficient D And

... (5)

... (6)

It is made to calculate by.
According to a sixth aspect of the present invention, in the motor control device according to the first or second aspect, when the constant disturbance force _Tc is known, the control constant identifying unit calculates the inertia total value J,

... (7)

It is made to calculate by.
The present invention is claimed in claim 7, wherein the motor control device according to claim 1 or 2, wherein the time differential value _V fb of the control constant identifying unit _{V fb} the _'time differentiated value _{T ref} of _{T ref'}
V _fb ′ = sV _fb × LPF (8)
T _ref ′ = sT _ref × LPF (9)
However, s is calculated by a Laplace operator and LPF is calculated by a transfer function of a low-pass filter.

The present invention is claimed in claim 8, wherein the motor control device according to claim 1 or 2, wherein the time differential value _V fb of the control constant identifying unit _{V fb} the _'time differentiated value _{T ref} of _{T ref'}
V _fb ′ = V _fb × (1-LPF) × α (10)
T _ref ′ = T _ref × (1-LPF) × β (11)
However, LPF is calculated by a transfer function of a low-pass filter and constants of α> 0 and β> 0.

The present invention of claim 9 is the motor control device according to claim 1 or 2, wherein the time differential value _V fb of the control constant identifying unit _{V fb} the _'time differentiated value _{T ref} of _{T ref',} utilizing the observer This is calculated.

  According to a tenth aspect of the present invention, in the motor control apparatus according to the first or second aspect, the identified inertia total value J and the identified viscous friction coefficient D can be adjusted by adjusting a control parameter or a feedforward signal. This is used for making or adjusting the vibration suppression compensator.

  The present invention according to claim 11 is the motor control device according to claim 10, wherein the feedforward signal is obtained by multiplying the differential value of the position command by the identified viscous friction coefficient D and the second-order differential value of the position command. And a value obtained by multiplying the identified inertia total value J.

According to the first aspect of the present invention, the inertia and the viscous friction coefficient can be accurately identified during the operation even when the viscous friction is large, or when there is a constant disturbance such as gravity or Coulomb friction.
According to the second aspect of the present invention, the inertia and the viscous friction coefficient can be accurately identified during the operation even when the viscous friction is large, or when there is a constant disturbance such as gravity or Coulomb friction.
According to the third aspect of the present invention, it is possible to accurately identify the inertia and the viscous friction coefficient during operation even when the viscous friction coefficient is large, or when there is a constant disturbance such as gravity or Coulomb friction.
According to the fourth aspect of the present invention, the inertia and viscous friction coefficient can be accurately identified during operation even when viscous friction is large, or when there is constant disturbance such as gravity or Coulomb friction, and the identification time is shortened. can do.
According to the invention of claim 5, the inertia and viscous friction coefficient can be accurately identified during operation even when the viscous friction is large, or when there is a constant disturbance such as gravity or Coulomb friction, and the identification time is shortened. can do.
According to the sixth aspect of the present invention, the inertia and the viscous friction coefficient can be accurately identified during the operation even when the viscous friction is large, or when there is a constant disturbance such as gravity or Coulomb friction, and the identification time is shortened. can do.
According to the seventh aspect of the present invention, it is possible to accurately identify the inertia and the viscous friction coefficient during operation even when the viscous friction coefficient is large, or when there is a constant disturbance such as gravity or Coulomb friction, and the torque command to be input is input. Inertia and viscous friction coefficient can be accurately identified even if there is an error due to difference approximation in T _ref or motor speed detection signal V _fb .
According to the eighth aspect of the invention, the inertia and the viscous friction coefficient can be accurately identified during operation even when the viscous friction is large, or when there is a constant disturbance such as gravity or Coulomb friction, and the torque command to be input Inertia and viscous friction coefficient can be accurately identified even if there is an error due to difference approximation in T _ref or motor speed detection signal V _fb .
According to the ninth aspect of the invention, the inertia and the viscous friction coefficient can be accurately identified during operation even when the viscous friction is large, or when there is a constant disturbance such as gravity or Coulomb friction, and the torque command to be input Even if there is an error due to a time delay in T _ref or the motor speed detection signal V _fb , the identification of the inertia and the viscous friction coefficient can be performed accurately.
According to the invention described in claim 10, even when the viscous friction coefficient is large, or when there is a constant disturbance such as gravity or Coulomb friction, the identified inertia and viscous friction coefficient are adjusted, the feedforward signal is created, or It can be used to adjust the vibration suppression compensator.
According to the eleventh aspect of the present invention, the identified inertia and viscous friction coefficient can be used to create a feedforward signal even when the viscous friction is large, or when there is a constant disturbance such as gravity or Coulomb friction. it can.

  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 are described and described in the figure. Hereinafter, the same reference numerals are assigned to the same names as much as possible, and duplicate explanations are omitted.

  FIG. 1 is a block diagram in a case where the present invention is applied to a drive device in which a load is applied to a motor 14. In FIG. 1, 10 is a speed command generation unit, 12 is a speed control unit, 13 is a torque control unit, 14 is a motor, 15 is a detector, 16 is a differentiator, 17 is a rigid load, and 18 is a control constant identification unit. .

The speed command generator 10 outputs a speed command V _ref to the speed controller 12. The speed control unit 12 generates a torque command T _ref so that the speed command V _ref matches the motor speed signal V _fb, and outputs the torque command T _ref to the torque control unit 13 and the control constant identification unit 18. The torque control unit 13 receives the torque command T _ref , performs a torque control calculation so that the torque generated by the motor 14 matches the torque command T _ref , and outputs a motor drive current _Im to the motor 14. Motor 14 is driven by the motor drive current I _m, to generate a torque. The load 17 is driven with the torque. The motor 14 is equipped with a detector 15 and outputs a position signal P _fb to the differentiator 16. The differencer 16 receives the position signal P _fb , calculates the speed signal V _fb by taking the difference of the position signal P _fb at fixed time intervals, and outputs the speed signal V _fb to the speed control unit 12 and the control constant identification unit 18. To do. The sum of the inertia of the control constant identifying unit 18 is a speed signal _{V fb} and the torque command _T inputs the _ref, velocity signal _{V fb} and the torque command _{T ref} load attached to the rotor inertia and the motor 14 of the motor 14 from 17 The value J and viscous friction coefficient D are calculated.

FIG. 2 is a block diagram in which FIG. 1 is modified so that the position of the motor 14 can be controlled. The difference between FIG. 1 in FIG. 2 instead of the speed command generating section 10 that generates a speed command V _ref, the position controller for generating a speed command V _ref as a position command P _ref and the position signal P _fb coincides 11 is provided.

  In this description, the torque command is based on the assumption that the output of the speed control unit is a rotary motor, but in the case of a linear motor, the output of the speed control unit may be realized with the same configuration as the thrust command. Therefore, if this invention is used, an inertia total value and a viscous friction coefficient can be identified in real time by numerical formula calculation.

A feature of the present invention is that it includes a control constant identification unit 18 that calculates an inertia J and a viscous friction coefficient D based on the torque command T _ref and the motor speed detection signal V _fb .

  Hereinafter, a specific calculation method will be described.

When the control target is expressed by inertia J, viscous friction D, and constant disturbance _Tc , the relational expression between the torque command _Tref and the motor speed _Vfb is expressed by Expression (12).

(12)

Here, dV _fb / dt is a time differential value of V _fb , but in actuality, in order to use a value calculated by a mathematical operation using claim 5 or claim 6,

(13)

far.
Multiplying both sides of the equation (12) by the time differential value of the motor speed V _fb and performing time differentiation in the interval [a, b]

(14)

Here, the second term on the right side of Equation (14) is

(15)

And rearranging equation (14),

... (16)

It becomes. Here, since V _fb ′ ² ≧ 0 in the third term of the equation (16), the denominator increases with time. Therefore, if the interval [a, b] is large, the equations (16) to (17 ) Is obtained.

... (17)

  Next, using the relational expression of Expression (12) and differentiating both sides with respect to time, Expression (18) is obtained.

... (18)

The third term on the right side of Equation (18) is 0 because it is a time derivative of the constant disturbance _Tc .
Here, since the first term and the second term on the right side actually use values calculated by mathematical formulas using claim 5 or claim 6,

... (19)


... (20)

far.

Next, by multiplying both sides of the equation (18) by the time differential value of the velocity V _fb and time differential in the interval [a, b],

... (21)

Here, the first term on the right side of Equation (21) is

(22)

And rearranging equation (21)

(23)

It becomes. Here, when D is eliminated from the equations (17) and (23), the equation (1) is obtained.

... (1)

When J is deleted from Expression (17) and Expression (23), Expression (2) is obtained.

... (2)

Further, in the expressions (1) and (2), the interval in which the absolute value | V _fb (a) | of the motor speed at time a and the absolute value | V _fb (b) | of the motor speed at time b coincide with each other. If [a, b], then equation (3) is obtained from equation (1), and equation (4) is obtained from equation (2).

Further, in the equations (1) and (2), the absolute value | V _fb ′ (a) | of the motor speed differential value at time a and the absolute value | V _fb ′ (b) | of the motor speed differential value at time b. If the interval [a, b] is such that they match, Expression (5) is obtained from Expression (1), and Expression (6) is obtained from Expression (2).

It should be noted _{that the} time differential value _V fb of _{V fb ',} the time differential value _{T ref} of _{T ref'} is,
V _fb ′ = sV _fb × LPF (8)
T _ref ′ = sT _ref × LPF (9)
However, s is a differential with a Laplace operator, and LPF is calculated by a transfer function of a low-pass filter, or V _fb ′ = V _fb × (1−LPF) × α (10)
T _ref ′ = T _ref × (1-LPF) × β (11)
However, s is a Laplace operator derivative, LPF is a low-pass filter transfer function, α> 0, β> 0 or a constant, or using an observer.

  FIG. 3 is a block diagram of a motor control apparatus for explaining an example in which the inertia total value and the viscous friction coefficient identified in the present invention are used to create a feedforward signal.

In FIG. 3, 21 is a feedforward signal generator. The feedforward signal generator 21 receives the position command _Pref of the position controller 11 and generates and outputs a feedforward signal ff. The sum of the output signal of the speed controller 12 and the feedforward signal ff becomes the torque command _Tref .

In feed-forward signal generator 21, s is a Laplace operator, FF _a and FF _b are feed-forward gain. J _i and D _i are the inertia total value J and the viscous friction coefficient D identified by the control constant identification unit 18 of the present invention.

For example, the feed forward signal ff is obtained by multiplying the position command P _ref by second order, the feed forward gain FF _a , and the identified inertia total value J _i , and the position command P _ref. the multiplied by 1-order differentiation ones and the feedforward gain FF _b, it can be obtained by adding the one obtained by multiplying a further identified viscous friction coefficient D _i.

  Thus, the present invention can be used to create a feedforward signal.

  Further, since the inertia total value J and the viscous friction coefficient D identified by the present invention are accurate, it is obvious that the control parameters such as the position loop gain and the speed loop gain can be adjusted based on them. .

  Further, as an example in which the inertia total value J and the viscous friction coefficient D identified by the present invention can be used for adjusting a vibration suppression compensator such as a disturbance observer, there is, for example, Japanese Patent No. 3360935.

  In this patent, by using the inertia total value J and viscous friction coefficient D identified by the present invention, the estimated disturbance signal is accurately calculated, and vibration suppression can be realized more easily.

  The present invention can be used as a motor control device for driving a machine tool or an industrial robot.

The block diagram of the motor control apparatus explaining the 1st example to which the present invention is applied. FIG. 1 is a block diagram of a motor control apparatus capable of performing position control according to a first embodiment to which the present invention is applied. The block diagram of the motor control apparatus explaining the 2nd example to which the present invention is applied. A block diagram of a motor control device for explaining a conventional inertia identification method

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Speed command generation part 11 Position control part 12 Speed control part 13 Torque control part 14 Motor 15 Detector 16 Differentiator 17 Load 18 Control constant identification part 21 Feedforward signal generator 51 Speed command generation part 52 Speed control part 53 Estimation part 54 Identification part

Claims (11)

A speed command generator for generating a speed command _{V ref,} a speed control unit for generating a torque command _{T ref} as the speed command _{V ref} and the motor speed detection signal _{V fb} coincides, the motor drive from the torque command _{T ref} In a motor control device comprising: a torque control unit that generates a current; and a detector that detects a position or speed of the motor and generates the motor speed detection signal V _fb .
An inertia total value J, which is a sum of values obtained by converting the rotor inertia value of the motor and the inertia value of the load machine driven by the motor into the rotation shaft of the motor, and the viscous friction coefficient D are used as the torque command. The relational expression from T _ref to the motor speed detection signal V _fb is multiplied by the time differential value V _fb ′ of the motor speed detection signal to integrate the time and the torque command T _ref to the motor speed detection signal V _fb . A motor control apparatus comprising: a control constant identification unit that converts and calculates a time integral value obtained by multiplying a time differential value V _fb ′ of the motor speed detection signal by a time derivative of the relational expression. A position controller that generates a speed command V _ref so that the position command P _ref and the motor position detection signal P _fb match, and a torque command T _ref so that the speed command V _ref and the motor speed detection signal V _fb match. A motor including a speed control unit that generates, a torque control unit that generates a motor drive current from the torque command T _ref , and a detector that detects the position or speed of the motor and outputs the motor speed detection signal V _fb In the control device,
An inertia total value J, which is a sum of values obtained by converting the rotor inertia value of the motor and the inertia value of the load machine driven by the motor into the rotation shaft of the motor, and the viscous friction coefficient D are used as the torque command. The relational expression from T _ref to the motor speed detection signal V _fb is multiplied by the time differential value V _fb ′ of the motor speed detection signal to integrate the time and the torque command T _ref to the motor speed detection signal V _fb . A motor control apparatus comprising: a control constant identification unit that converts and calculates a time integral value obtained by multiplying a time differential value V _fb ′ of the motor speed detection signal by a time derivative of the relational expression. The control constant identification unit calculates the inertia total value J and the viscous friction coefficient D.

... (1)

... (2)
_{However, T ref} 'is _T time derivative of _{ref, V fb'} is _V time derivative of _fb, a and b represent arbitrary time b> a
The motor control device according to claim 1, wherein the motor control device is calculated by: The control constant identification unit determines the interval [a, b] for calculating the inertia total value J as the absolute value | V _fb (a) | of the motor speed at time a and the absolute value of the motor speed at time b. | V _fb (b) | is a section in which the values coincide with each other, and the inertia total value J and the viscous friction coefficient D are

... (3)

... (4)
The motor control device according to claim 1, wherein the motor control device is calculated by: The control constant identification unit determines an interval [a, b] for calculating the inertia total value J as an absolute value | V _fb ′ (a) | of a motor speed differential value at a time a and a motor speed at a time b. The section is such that the absolute value | V _fb ′ (b) | of the differential value matches, and the inertia total value J and the viscous friction coefficient D are

... (5)

... (6)
The motor control device according to claim 1, wherein the motor control device is calculated by: When the constant disturbance force _Tc is known, the control constant identification unit calculates the inertia total value J,

... (7)
The motor control device according to claim 1, wherein the motor control device is calculated by: Said control constant identification _unit, the time differential value _V fb of _{V fb ',} the time differential value _{T ref} of _{T ref',}
V _fb ′ = sV _fb × LPF (8)
T _ref ′ = sT _ref × LPF (9)
3. The motor control device according to claim 1, wherein s is calculated by a Laplace operator and LPF is calculated by a transfer function of a low-pass filter. Said control constant identification _unit, the time differential value _V fb of _{V fb ',} the time differential value _{T ref} of _{T ref',}
V _fb ′ = V _fb × (1-LPF) × α (10)
T _ref ′ = T _ref × (1-LPF) × β (11)
3. The motor control device according to claim 1, wherein the LPF is calculated by a transfer function of a low-pass filter and constants of α> 0 and β> 0. The control constant identification unit, the time differential value V _fb of V _fb the _'time differentiated value T _ref of T _ref', the motor control device according to claim 1 or 2, wherein the calculating using the observer .   The identified inertia total value J and the identified viscous friction coefficient D are used for adjusting a control parameter, creating a feedforward signal, or adjusting a vibration suppression compensator. 2. The motor control device according to 2.   A value obtained by multiplying the feedforward signal by a value obtained by multiplying the differential value of the position command by the identified viscous friction coefficient D and a value obtained by multiplying the second-order differential value of the position command by the identified total inertia value J. The motor control device according to claim 10, wherein