JP5644118B2 - Position control device - Google Patents

Description

  The present invention relates to a position control device, and more particularly to position control by a two-degree-of-freedom control system of an electric motor having current control and speed control in a minor loop and having position control as a major loop.

FIG. 3 shows a schematic configuration diagram of the position control device, where 1 is a position control unit, 2 is a speed control unit, 3 is a current control unit, and 4 is a mechanical characteristic of a rotating body that is a controlled object. is there. The speed control unit 2 calculates an angular speed command ωref based on a deviation signal between the angle command θref and the detected angle value θdet input to the position control device. The calculated angular velocity command ωref is obtained as a difference signal from the angular velocity detection ωdet in the subtraction unit 6 and input to the speed control unit 2 to produce the torque current command Tdy. Based on this torque current command Tdy, the mechanical characteristic unit 4 which is a controlled object is controlled via the current control unit 3, and the detected angular velocity value ωdet of the mechanical characteristic unit 4 at that time is fed back to the subtracting unit 6 to be compared with the angular velocity command ωref. A difference operation is performed. Further, the detected angle value θdet of the mechanical characteristic unit 4 is fed back to the subtracting unit 5 and a difference calculation with the angle command θref is executed.
Note that Patent Document 1 and the like are publicly known for performing position control as described above. In this patent document 1, a vibration suppression compensator is provided to suppress vibrations of the mechanical system even if parameters such as the resonance / semi-resonance frequency of the mechanical system are not known. Is input to a vibration suppression compensator to generate a speed command compensation signal, and the sum of this compensation signal and the speed command basic signal is used as a speed signal.

JP 2002-325473 A

As shown in FIG. 3, in the position control by the electric motor, the speed control system has a minor loop and the position control has a major loop. In the minor loop speed control, the speed is controlled by P (proportional) I (integral) control. In the position control of the major loop, the position is controlled by P (proportional) control. Conventionally, both of these adjustments are performed by adjusting the position control after adjusting the speed control system.
In recent years, a stable and highly responsive frequency characteristic has been demanded for the purpose of vibration or the like. However, in conventional feedback system control, adjustment for achieving high response is difficult.

  Accordingly, an object of the present invention is to provide a position control device that enables position control of a highly responsive command value response.

According to the first aspect of the present invention, an angular velocity command value is calculated by inputting a deviation signal based on an angle command value and an angle detection value to a position control unit, and the deviation signal between the angular velocity command value and the angular velocity detection value is proportional to an integral element. A torque current command value is calculated by inputting to a speed control unit having an element, and a controlled object is controlled via the current control unit based on the torque current command value.
The position control unit is provided with a feedforward unit, and when the angular velocity detection of the control object is ωdet, the angle detection is θdet, the motor inertia is Jdy, and the rotation loss is Ddy, an angle command θref input to the position control unit The transfer function of the position control device is obtained by the following equation from the ratio of the angle detection θdet of the control object and
θdet / θref = {KIω (FFθ + KPθ)} / { Jdys ³ + (KPω + Ddy)
s ² + KIωs + (KIω * KPθ)} (1) ′
(Where KPθ is the proportional parameter of the position controller, KPω and KIω are the proportional and integral parameters of the speed controller, and s is the Laplace operator)
When the angle command θref is a step-like command, the zero point of the numerator polynomial of the above equation = KIω (FFθ + KPθ) = KIω * KPθ as the constant term of the denominator polynomial
From the above, the parameter FFθ of the feedforward unit is set to be equal to the state where the two-degree-of-freedom control is not added, and the position control unit and the speed control unit are set by setting the motor inertia Jdy, the rotation loss Ddy, and the frequency response setting wc. Each parameter KPθ, KPω, KIω, and FFθ of the control unit and the speed control unit is obtained and configured.
The second of the present invention, when the angle command θref input to the position control unit is a lamp command,
The parameter FFθ of the feedforward unit is defined as KIω (FFθ + KPθ) = (KIω * KPθ) + KIωs, where zero of the numerator polynomial of the equation (1) ′ = constant term of denominator polynomial + 1st order
From the above, the parameter FFθ of the feedforward unit is obtained by s / G (s) (where G (s) is an arbitrary transfer function having a relative order of the first order or higher),
The position control unit and the speed control unit are configured by determining the parameters KPθ, KPω, KIω, and FFθ of the position control unit and the speed control unit by setting the motor inertia Jdy, the rotation loss Ddy, and the frequency response setting wc. It is characterized by.
According to a third aspect of the present invention, when the angle command θref input to the position control unit is an acceleration command, the parameter FFθ of the feedforward unit is set to zero of the numerator polynomial of the equation (1) ′ = constant of the denominator polynomial. KIω (FFθ + KPθ) = (KIω * KPθ) + KIωs + (KPω + Ddy) s ² as the term + first order + ^{second order}
From the above, the parameter FFθ of the feedforward unit is determined by {(Ddy + KPω) s ² + KIωs} / {KIω * G (s)} (where G (s) is an arbitrary transfer function having a relative degree of second order or higher),
The position control unit and the speed control unit are configured by determining the parameters KPθ, KPω, KIω, and FFθ of the position control unit and the speed control unit by setting the motor inertia Jdy, the rotation loss Ddy, and the frequency response setting wc. It is characterized by.

As described above, according to the present invention, by providing the feed forward unit FFθ and setting the motor inertia Jdy, the rotation loss Ddy, and the frequency response setting wc, the position control unit and the speed control unit KPθ, KPω are uniquely set. , KIω, and FFθ parameters can be set, and high-response speed control without a steady deviation by a step-like input command can be realized.

The block diagram of the position control apparatus which shows the Example of this invention. The block diagram of the position control apparatus for demonstrating this invention. The block diagram of the conventional position control apparatus.

In the present invention, in the position control device, the position control unit is provided with a feedforward unit FFθ, and by setting the motor inertia Jdy, the rotation loss Ddy, and the frequency response setting wc, which are transfer functions of the mechanical characteristics of the controlled device, Uniquely, KPθ, KPω, KIω, and FFθ parameters of the position control unit and the speed control unit can be set.
As a result, position control without a steady deviation is enabled regardless of whether the input command (angle command) is stepped, ramped, or acceleration command.
Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

FIG. 1 is a schematic configuration diagram of a position control apparatus according to an embodiment of the present invention.
Reference numeral 10 denotes a position control unit in which a feedforward FFθ is added to the proportional element KPθ. A speed control unit 20 is a deviation signal obtained by subtracting the angle detection ωdet [rad / s] from the sum signal of the angular velocity command ωref [rad / s] and the feedforward command obtained by the addition / subtraction unit 7 as an integral element KIω / s. The angle detection ωdet is input to the proportional element KPω. The subtracting unit 8 calculates the difference between them to generate a torque current command Tdy, and controls the mechanical characteristic 4 that is a rotating body via the current control unit 3.
Here, Jdy is motor inertia [kgm ² ], Ddy is rotation loss [Nms / rad], θref is an angle command [rad], θdet is an angle detection value [rad], and s is a Laplace operator.

Prior to the description of the embodiment shown in FIG. 1, the case where the position control shown in FIG. 2 is P control and the speed control is IP control will be described.
If the current control unit has a high response characteristic that does not affect the frequency band of position control and speed control, the following equation may be used.
ωref = KPθ * (θref−θdet) (1)
ωdet = θdet * s (2)
Tdy = {(KIω / s) * (ωref−ωdet)} − (KPω * ωdet) (3)
{(Jdy * s) + Ddy} ωdet = Tdy (4)
By solving for θdet / θref from the above equations (1) to (4), θdet / θref = (KIω * KPθ) / {Jdys ³ + (KPω + Ddy) s ² + KIωs + (KIω * KPθ)} (5)
It becomes.
The denominator polynomial of equation (5) is a cubic equation, and the first to third coefficients of the equation in which the denominator polynomial is divided by the constant term KIω * KPθ and the constant term is 1 are independent of KPθ, KPω, and KIω. It has become. Therefore, when the coefficient comparison is performed so that the denominator polynomial of the equation (5) becomes 1 + c1 * s + c2 * s ² + c3 * s ³ , KPθ = 1 / c1 (6)
KPω = (c2 * Jdy / c3) −Ddy (7)
KIω = c1 * Jdy / c3 (8)
The parameters KPθ, KPω, and KIω may be determined so that For example, a binomial counting type (s + 1) ³ = 1 + 3 * s + 3 * s ² + 1 * s ^{3 in} which all poles have a damping coefficient 1 is obtained, s is replaced with s / ws, and the coefficients are c1, c2, and c3. Then, the binary-counting, and c1 = 3 / wc, c2 = 3 / wc 2, c3 = 1 / wc 3. For these c1 to c3, parameters KPθ, KPω, and KIω of the position control unit 1 and the speed control unit 20 expressed by the equations (6) to (8) are determined.

In the embodiment shown in FIG. 1, the speed control unit 10 is configured by adding a feedforward FFθ to the position control unit based on the above.
When feed forward FFθ is added,
ωref = {KPθ * (θref−θdet)} + (FFθ * θref) (9)
ωdet = θdet * s (10)
Tdy = {(KIω / s) * (ωref−ωdet)} − (KPω * ωdet) (11)
{(Jdy * s) + Ddy} ωdet = Tdy (12)
By solving for θdet / θref from the above equations (9) to (12), θdet / θref = {KIω (FFθ + KPθ)} / { Jdys ³ + (KPω + Ddy)
s ² + KIωs + (KIω * KPθ)} (13)
Thus, the transfer function of the position control device can be obtained by dividing the angle detection θdet of the controlled object input to the position control unit 10 by the angle command θref.
Next, when the angular velocity command θref to the position control unit 10 is a step-like command, the zero point of the numerator polynomial is arranged so that a steady deviation of the step command does not occur. In order to remove the steady-state deviation of the stepped command, if the equation (13) is set to zero of the numerator polynomial = denominator polynomial,
KIω (FFθ + KPθ) = KIω * KPθ (14)
It becomes. That is, the numerator term of the transfer function of the position control device obtained by the equation (13) is equivalent to the product value of the integral element KIω of the speed control unit 20 and the proportional element KPθ of the position control unit 10 which are constant terms on the denominator side. To. Thereby, FFθ of the feedforward unit is FFθ = 0 (15)
become. The fact that FFθ = 0 is equivalent to a state where 2-degree-of-freedom control is not added.
Therefore, according to this embodiment, the position control unit is provided with the feed forward unit FFθ, and the motor inertia Jdy, the rotation loss Ddy, and the frequency response setting wc are set, so that the position control unit and the speed control unit KPθ are uniquely set. , KPω, KIω, and FFθ parameters can be set, and the position control unit and the speed control unit are configured based on the setting of each parameter, so that a highly responsive position without a steady deviation by a step-like input command Control can be realized.

In this embodiment, the angle command θref input to the position control unit 10 is an example of a lamp command. Also in this case, as in the first embodiment, the position control is previously set to P control, the speed control is designed by IP control, and 2-degree-of-freedom control is added.
The zeros of the numerator polynomial are arranged so that the steady deviation of the ramp command does not occur.
From equation (13), if the zero of the numerator polynomial = the constant term of the denominator polynomial + 1st order,
KIω (FFθ + KPθ) = (KIω * KPθ) + KIωs (16)
And
FFθ = s (17)
Where FFθ = s / G (s) (18)
By doing so, position control without a steady deviation of the lamp command becomes possible. However, G (s) is an arbitrary transfer function having a relative degree of 1st order or higher.

Therefore, according to this embodiment, even when the angle command θref is a ramp command,
Similarly to the first embodiment, the feedforward unit FFθ is provided and the motor inertia Jdy, the rotation loss Ddy, and the frequency response setting wc are set, so that the position control unit and the speed control unit KPθ, KPω, KIω, And FFθ parameters can be set, and a highly responsive position control without a steady deviation by a ramp command can be realized.

In this embodiment, when the input to the position control unit 10 is an acceleration command, it is possible to realize speed control with high response so that no steady deviation occurs. Even when the input command is an acceleration command, the design is performed in the same manner as in the first embodiment shown in FIG. 1, and the zeros of the numerator polynomial are arranged so that a steady deviation of the acceleration command does not occur.
From equation (13), if the zero of the numerator polynomial = the constant term of the denominator polynomial + 1st order + second order,
KIω (FFθ + KPθ) = (KIω * KPθ) + KIωs + (KPω + Ddy) s ² (19)
And
FFθ = {(Ddy + KPω) s ² + KIωs} / KIω (20)
become. Here, FFθ = {(Ddy + KPω) s ² + KIωs} / {KIω * G (s)} (21)
By doing so, position control without steady deviation of the acceleration command becomes possible.
However, G (s) is an arbitrary transfer function having a relative order of second order or higher.
Therefore, according to this embodiment, by providing the feedforward unit FFθ and setting the motor inertia Jdy, the rotation loss Ddy, and the frequency response setting wc, the position control unit without steady deviation and the speed control unit KPθ, The KPω, KIω parameter, and FFθ parameter can be set, and high-responsive position control without a steady deviation by the acceleration command can be realized.

DESCRIPTION OF SYMBOLS 1, 10 ... Position control part 2, 20 ... Speed control part 3 ... Current control part 4 ... Mechanical property part 5, 6, 8 ... Subtraction part 7 ... Addition / subtraction part

Claims (3)

An angular velocity command value is calculated by inputting a deviation signal based on the angle command value and the angle detection value to the position control unit, and the deviation signal between the angular velocity command value and the angular velocity detection value is input to the speed control unit having an integral element and a proportional element. Input the torque current command value and calculate the control object via the current control unit based on the torque current command value.
The position control unit is provided with a feedforward unit, and when the angular velocity detection of the control object is ωdet, the angle detection is θdet, the motor inertia is Jdy, and the rotation loss is Ddy, an angle command θref input to the position control unit The transfer function of the position control device is obtained by the following equation from the ratio of the angle detection θdet of the control object and
θdet / θref = {KIω (FFθ + KPθ)} / { Jdys ³ + (KPω + Ddy)
s ² + KIωs + (KIω * KPθ)} (1) ′
(Where KPθ is the proportional parameter of the position controller, KPω and KIω are the proportional and integral parameters of the speed controller, and s is the Laplace operator)
When the angle command θref is a step-like command, the zero point of the numerator polynomial of the above equation = KIω (FFθ + KPθ) = KIω * KPθ as the constant term of the denominator polynomial
From the above, it is assumed that the parameter FFθ of the feedforward unit is equivalent to a state where the two-degree-of-freedom control is not added, and the position control unit and the speed control unit are set by setting the motor inertia Jdy, the rotation loss Ddy, and the frequency response setting wc. A position control device characterized by determining and configuring each parameter KPθ, KPω, KIω, and FFθ of a control unit and a speed control unit. When the angle command θref input to the position control unit is a lamp command,
The parameter FFθ of the feedforward unit is defined as KIω (FFθ + KPθ) = (KIω * KPθ) + KIωs, where zero of the numerator polynomial of the equation (1) ′ = constant term of denominator polynomial + 1st order
From the above, the parameter FFθ of the feedforward unit is obtained by s / G (s) (where G (s) is an arbitrary transfer function having a relative order of the first order or higher),
The position control unit and the speed control unit are configured by determining the parameters KPθ, KPω, KIω, and FFθ of the position control unit and the speed control unit by setting the motor inertia Jdy, the rotation loss Ddy, and the frequency response setting wc. The position control device according to claim 1. When the angle command θref input to the position control unit is an acceleration command, the parameter FFθ of the feedforward unit is set to zero of the numerator polynomial of the equation (1) ′ = constant term of denominator polynomial + 1st order + second order KIω (FFθ + KPθ) = (KIω * KPθ) + KIωs + (KPω + Ddy) s ²
From the calculation of the parameter FFθ of the feedforward unit by {(Ddy + KPω) s ² + KIωs} / {KIω * G (s)} (where G (s) is an arbitrary transfer function having a relative order of second or higher). The position control unit and the speed control unit are obtained by determining the parameters KPθ, KPω, KIω, and FFθ of the position control unit and the speed control unit by setting the motor inertia Jdy, the rotation loss Ddy, and the frequency response setting wc. The position control device according to claim 1, wherein:

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