JPH11258076A - Motor torque ripple measuring device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a torque ripple measuring device for measuring the torque ripple data depending on an angle generated by a motor without being influenced by friction or the like independently from the torque ripple increased in proportion to the torque ripple independent of the generated torque of the motor. SOLUTION: This measuring device includes a learning control device 2 for repeatedly correcting the control input so that a motor is rotated at a constant speed and finally realizing the constant-speed drive, taking a torque command, a speed command or a position command as the control input, and memories 4, 5 for collecting the torque command data Tr (θn) (N=1, 2, ..., N) corresponding to the motor angle (0 deg.<=θn<360 deg., n=1, 2, ..., N) for one rotation during constant speed rotation realized by the learning control device 2, and determine the torque ripple data from the torque command data by an operating device 3 and store the same.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a motor torque ripple measuring device for measuring a torque ripple generated depending on an angle of a motor.

[0002]

2. Description of the Related Art As a conventional technique for measuring torque ripple, there is a method in which a motor is rotated at a constant low speed by another rotating device, and a torque applied to a motor shaft at that time is measured (for example, Japanese Patent Laid-Open No. Hei 5 -149803).

[0003]

The torque ripple generated by the motor depending on the relative angle between the stator and the rotor is a fixed value such as cogging torque regardless of the magnitude of the generated torque of the motor. Some increase in proportion to the generated torque. However, the conventional technique has a problem that only the cogging torque can be measured, and an error occurs due to the influence of Coulomb friction or viscous friction. In addition, there is a problem that the measurement takes a long time because the measurement can be performed only at a very low speed. Therefore, the present invention provides a torque ripple measurement that measures torque ripple data dependent on an angle generated by a motor separately from data that does not depend on torque generated by the motor and that is not affected by friction or the like. It is intended to provide a device.

[0004]

SUMMARY OF THE INVENTION In order to solve the above problems, the present invention is a torque ripple measuring device for a motor provided with an angle detector, wherein a torque command, a speed command, or a position command is used as a control input. A learning control device that repeats the correction of the control input so that the motor rotates at a constant speed, and finally realizes driving at a constant speed, and a motor for one rotation at a constant speed rotation realized by the learning control device. Collect the torque command data Tr (θn) (n = 1,2,…, N) corresponding to the angle (0 degree ≦ θn <360 degree, n = 1,2, ..., N),
Means for obtaining and storing torque ripple data from the torque command data.

[0005]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIG. In the figure, reference numeral 6 denotes a motor provided with an angle detector 7, to which a torque generator 8 for generating a constant torque is connected. Although various types of torque generators 8 are conceivable, another motor that generates a constant torque may be connected, or a constant torque may be generated by connecting a weight. Reference numeral 1 denotes a torque ripple measuring device, which comprises a learning control device 2 for driving a motor 6 at a constant speed, an arithmetic unit 3 for obtaining torque ripple data, and memories 4 and 5 for storing torque ripple data. The learning control device 2 receives a torque command, a speed command, or a position command as a control input,
The correction of the control input is repeated so that the motor 6 rotates at a constant speed, and finally the driving at a constant speed is realized. There are many learning control methods. For example, a case will be described in which the third invention of Japanese Patent Application Laid-Open No. Hei 6-324710 “Learning Control Device” is applied. In order to rotate the motor at a constant speed, the increment value Δr (i) between the sampling cycle Ts of the target angle command r (i) at the time i · Ts is set to a constant value dr. Hereinafter, time i · Ts is referred to as time i for convenience. For this target angle command r (i), the control input u (i) is
(1a). u (i) = u (i ') + σ (i) (1a) Here, time i' is the time one cycle before, and (i-i '). dr
Makes one rotation. σ (i) is the control input u (i ')
, And is given by the following equation (1b).

[0006]

(Equation 1)

Here, e is a deviation between the target angle command and the motor angle, and Δ represents an increment value during the sampling cycle. v _m , p _n , g _n , E are coefficients determined by a discrete-time transfer function model from the control input u to the increment value of the motor angle, Na and Nb are model orders, and M is a prediction interval of future deviation. is there. According to the equation (1b), the correction amount is determined so that the future deviation predicted using the transfer function model is minimized, so that if the correction of the equation (1) is continued, the deviation decreases rapidly,
Rotation at a constant speed according to the target angle command is realized. When the learning is completed, the motor angle for one rotation at the realized constant speed rotation (0 degree ≦ θn <360 degree, n = 1,
2, ..., N) corresponding to the torque command data Tr (θn) (n = 1,2,
.., N) are output from the learning control device 2 to the arithmetic unit 3. Calculator 3 Tcg a than the torque ripple data more torque command data obtained as a result of the learning control unit 2 has learned under different conditions ^{(θn) = {Tr + (} θn) + Tr - (θn)} / 2 (n = 1,2,..., N) (2), stored in the memory 4, and further, Trp (θn) = {Tr1 (θn) -Tr2 (θn)-(Td1-Td2)} / (Td1-Td2) ) (n = 1, 2,..., N) (3) and stored in the memory 5. Where Tr ⁺ (θn)
Tr and ^- (.theta.n) is a torque command data obtained as a result of learning, respectively for positive rotation command Derutaaru≡dr 'and reverse rotation command Δr≡ -dr', and Tr1 (θn) Tr2 (θn) is , Two kinds of constant torques -Td1 and -Td2 by the torque generator 8
Is applied to the motor, and the rotation command Δr≡dr ”
Is torque command data obtained as a result of learning with respect to. Equations (2) and (3) will be described. First, Tr ⁺ (θ
n) is a torque command for realizing positive rotation Δr≡dr ', so the following equation Tr ⁺ (θn) ≒ Tq ⁺ (θn)) 1 + Trpl (θn)｝ Tcog (θn) + Tclb + D・ It is considered that dr '/ Ts｝ (4) holds. Here, Tq ⁺ is the motor torque, Trpl is the proportional constant at each angle of the torque ripple proportional to the motor torque, Tcog is the torque ripple not proportional to the motor torque such as cogging torque, Tclb is Coulomb friction, and D is the viscous friction coefficient. is there. Similarly, the following equation Tr For reverse rotation ^{- (θn) ≒ Tq - (} θn) ≒ {1 + Trpl (θn)} · {Tcog (θn) - Tclb - D · dr '/ Ts} (5) Is considered to hold. Therefore, from equations (4) and (5),
(2) expression, Tcg (θn) = {Tr + (θn) + Tr - (θn)} / 2 ≒ {1 + Trpl (θn)} · Tcog (θn) ≒ Tcog (θn) (n = 1, 2, ..., N) (6), and a torque ripple that is not proportional to the motor torque is obtained. Next, Tr1 (θn) and Tr2 (θn) are equal to a constant torque −Td1
Tr1 (θn) そ れ ぞ れ Tq1 (θn) ≒ ｛1 + Trpl (θn)｝ Tcog (θn ) + Tclb + D ・ dr ”/ Ts + Td1｝ (7) Tr2 (θn) ≒ Tq2 ≒ ｛1 + Trpl (θn)｝ ｛Tcog (θn) + Tclb + D ・ dr” / Ts + Td2｝ ( Where Tq1 and Tq2 are the motor torques.From the above equation, Tr1 (θn) −Tr2 (θn) ≒ ｛1 + Trpl (θn)｝ · (Td1-Td2) (9 ), Trp (θn) = = Tr1 (θn) -Tr2 (θn)-(Td1-Td2)｝ / (Td1-Td2) ≒ Trpl (θn) ,…, N) (10) to obtain the torque ripple proportionality constant proportional to the motor torque.If the time dtm until the torque command is reflected in the actual torque cannot be ignored, Angular velocity dθ / dt = product of dr / Ts and dtm (dθ / dt) ・ dt
m and the torque ripple data Tcg (θn) and Tr
p (θn) is shifted with respect to the angle θn.For example, the value calculated on the right side of the equation (2) is not Tcg (θn) but Tcg (θn + (dθ / dt)
・ Dtm) Further, when measurement data of the torque applied to the motor shaft is obtained by the torque sensor, torque measurement data may be used instead of the torque command data. In the present invention, "rotation" means "movement",
If "angle" is replaced with "relative position", "rotor is mover", and "motor angle for one rotation" is replaced with "relative position of stator and mover", it can be applied to linear motor. Needless to say.

[0008]

As described above, according to the present invention, the torque ripple data depending on the angle generated by the motor is separately calculated from the torque ripple data which increases in proportion to the torque independent of the motor generated torque. Since the measurement can be performed without being affected by such factors, there is an effect that a torque ripple measuring device with high measurement accuracy can be realized.

[Brief description of the drawings]

FIG. 1 is a diagram showing a specific embodiment of the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Torque ripple measuring device 2 Learning control device 3 Computing unit 4, 5 Memory for storing torque ripple data for one rotation 6 Motor 7 Angle detector 8 Torque generator

Claims (5)

[Claims] An apparatus for measuring torque ripple of a motor including an angle detector, wherein a torque command, a speed command, or a position command is used as a control input to repeatedly correct a control input so that the motor rotates at a constant speed. A learning control device that finally realizes driving at a constant speed, and a motor angle for one rotation (0 degrees ≦ θn <360 degrees, n = 1, at the time of constant speed rotation realized by the learning control device).
2, ..., N) corresponding to the torque command data Tr (θn) (n = 1,2,
.., N), and obtains and stores torque ripple data from the torque command data. Wherein said learning control unit forward and allowed reverse drive the motor at a constant speed by its two collected during the torque command data Tr ⁺ and (θn) Tr ^- Tcg by using the (.theta.n) ( ^{θn) = {Tr + (θn} ) + Tr - (θn)} / 2 (n = 1,2, ..., n) by claim 1, wherein further comprising means for storing calculated torque ripple data Motor torque ripple measuring device. 3. The learning control device drives the motor at a constant speed in a state where two types of constant torques -Td1 and -Td2 are applied to the motor, and collects two types of torque command data Tr1 ( Trp (θn) = {Tr1 (θn) -Tr2 (θn)-(Td1-Td2)} / (Td1-Td2) using (θn) and Tr2 (θn) (n = 1,2,…, N) 2. The motor torque ripple measuring device according to claim 1, further comprising means for obtaining and storing torque ripple data according to: 4. The product (dθ) of the angular velocity dθ / dt at a constant speed and the time dtm until the torque command is reflected on the actual torque.
/ dt) · dtm to the torque ripple data at the angle θ
4. A motor torque ripple measuring device according to claim 1, further comprising means for shifting with respect to n. 5. The motor torque ripple measuring device according to claim 1, wherein torque measurement data measured by a torque sensor is used instead of the torque command data.