JP2017034936A - Motor control apparatus, motor device, and motor control method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a motor control apparatus capable of implementing stable torque control, a motor device and a motor control method.SOLUTION: The motor control apparatus comprises: a back drivability control part for calculating an acceleration command value based on a measurement of torsion torque that is disturbance torque of a motor for mechanically transmitting drive power to a load in accordance with a load side torque command value and the load side torque command value; a disturbance observer which estimates the disturbance torque of the motor; and an acceleration control part for calculating a current command value to be inputted to the motor based on the acceleration command value calculated by the back drivability control part and an estimate of the disturbance torque of the motor outputted from the disturbance observer.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a motor control device, a motor device, and a motor control method.

  In automatic devices such as industrial robots and power assist devices, for example, servomotors are used for movable parts such as robot joints. For example, an automatic device such as a robot controls the position of a load connected to the servo motor via a speed reduction mechanism and the torque applied to the load by controlling the rotation angle and torque of the rotation axis of the servo motor. And it realizes work close to humans. In such an automatic device, when working, a disturbance such as some force is applied to the load, and when a disturbance torque such as a torsion torque is applied from the load to the motor, the torque applied to the load does not follow the control target value. There is a case. Even in such a case, various control devices have been developed in consideration of disturbance torque so that the torque can be quickly set to the control target value and stable torque control can be performed.

  For example, a motor control device disclosed in Patent Document 1 is a motor-side disturbance observer that outputs an estimated value of disturbance torque applied to a motor by inputting a current command value to the motor and an angular velocity response value of the motor. And an angular velocity response value of the load connected to the motor and an estimated value from the motor-side disturbance observer, the load-side disturbance observer that outputs an estimated value of the load disturbance torque separated from the motor torsional torque And.

  The motor control device disclosed in Patent Document 1 realizes torque control that compensates for disturbance torque by controlling the torque applied to the load by feeding back the estimated value of the disturbance torque from the load-side disturbance observer to the current command value. ing.

JP 2008-228484 A

  However, in the motor control device disclosed in Patent Document 1, the disturbance observer parameters cannot be changed even if the characteristics of the control system change due to aging or the like, and therefore the disturbance observer cannot properly compensate the disturbance torque. There is a problem that it is difficult to perform stable torque control.

  Then, an object of this invention is to provide the motor control apparatus, motor apparatus, and motor control method which can implement | achieve stable torque control.

  The motor control device according to the present invention provides an acceleration command based on a measured value of torsion torque, which is a disturbance torque of a motor that mechanically transmits a driving force to a load in accordance with a load side torque command value, and the load side torque command value. A back drivability control unit for calculating a value, a disturbance observer for estimating a disturbance torque of the motor, the acceleration command value calculated by the back drivability control unit and the motor output from the disturbance observer And an acceleration control unit that calculates a current command value to be input to the motor based on an estimated value of disturbance torque.

  A motor device of the present invention includes the motor control device according to claim 1 and a torque measuring unit that measures the torsion torque, and one end of the torque measuring unit is connected to the motor via a speed reduction mechanism. A strain gauge disposed on a rotating shaft that generates torque according to the load-side torque command value at the other end to which the load is connected, and a resistance change of the strain gauge is detected, and the twist is detected from the detected resistance change. And a torque detection circuit for calculating torque.

  The motor control method according to the present invention provides an acceleration command based on a measured value of torsion torque, which is a disturbance torque of a motor that mechanically transmits a driving force to a load in accordance with a load side torque command value, and the load side torque command value. And calculating a current command value to be input to the motor based on the acceleration command value and an estimated value of disturbance torque of the motor estimated by a disturbance observer.

  According to the present invention, the back drivability control unit can feed back the measured value of the torsional torque actually measured to the load side torque command value to compensate for the disturbance torque and suppress the vibration, and is calculated by the disturbance observer. The estimated value of the disturbance torque of the motor is fed back to the current command value by the acceleration control unit to compensate for the dynamic friction of the motor, so that the disturbance torque can be compensated even when aging occurs, and stable torque control can be realized. .

It is the schematic which shows the whole structure of the motor apparatus using the motor control apparatus of this invention. It is the schematic which shows the cross section of the torque detector integrated reduction gear of embodiment of this invention. It is a block diagram which shows the motor control apparatus of embodiment of this invention. It is the schematic which shows the cross section of the torque detector integrated reduction gear of the modification of this invention. It is the schematic which shows the cross section of the torque detector integrated reduction gear of the modification of this invention.

(1) Configuration of Motor Device Using Motor Control Device of Embodiment of Present Invention As shown in FIG. 1, the motor device 1 of this embodiment includes a motor 2 and one end of a rotating shaft (not shown) of the motor 2. The torque detector-integrated speed reducer 3 connected to the motor 2, the rotary encoder 4 connected to the other end of the rotating shaft of the motor 2, the motor 2 and the torque detector-integrated speed reducer 3 are supplied with electric power, and the motor 2 A motor control device 5 for controlling the motor is provided.

  When electric current is supplied from the motor control device 5, the motor 2 rotates the rotation shaft to generate torque, and transmits driving force to the torque detector integrated speed reducer 3. The motor 2 is not particularly limited, and is a DC motor in this embodiment.

  The torque detector integrated speed reducer 3 includes a rotating shaft 6, a torque measuring unit 8, and a speed reducing mechanism 10, and the rotating shaft of the motor 2 and one end of the rotating shaft 6 are connected via the speed reducing mechanism 10. ing. In the torque detector integrated speed reducer 3, the speed reduction mechanism 10 converts the rotational speed and torque of the rotating shaft of the motor 2 in accordance with the reduction ratio, and transmits the converted speed to the rotating shaft 6. The other end of the rotating shaft 6 can be connected to a load such as a robot arm. The torque detector integrated speed reducer 3 further includes a torque measurement unit 8 that measures the torsion torque generated on the rotating shaft 6 and outputs a measurement value of the torsion torque.

  The rotary encoder 4 detects the position of the rotation shaft of the motor 2, that is, the rotation angle of the rotation shaft from a predetermined reference point (hereinafter referred to as the position response value of the motor 2), converts it into an electrical signal, and outputs it. .

  The motor control device 5 is connected to the motor 2, the torque detector integrated speed reducer 3, and the rotary encoder 4 via wires 7a, 7b, and 7c, respectively.

  The motor control device 5 supplies a current to the motor 2 via the wiring 7a. The motor control device 5 receives the measured value of the torsion torque output from the torque detector integrated reduction device 3 via the wiring 7b. The motor control device 5 receives the position response value of the motor 2 output from the rotary encoder 4 via the wiring 7c.

  When the load is connected to the rotating shaft 6, the motor control device 5 is configured so that the torque applied to the load follows a predetermined value (load side torque command value described later) and the motor 2. A current command value is calculated based on the position response value and the torsion torque, and the current command value is input to the motor 2 to control the motor 2. Here, inputting the current command value to the motor means supplying a direct current corresponding to the current command value to the motor.

  Next, the structure of the torque detector integrated speed reducer 3 will be further described. As shown in FIG. 2, the torque detector integrated speed reducer 3 includes a rotating shaft 6, a torque measuring unit 8, a speed reducing mechanism 10, a part of the rotating shaft 6 and a housing 12 that houses the speed reducing mechanism 10. A bearing 13 that rotatably supports the rotating shaft 6 with respect to the housing 12 and a shaft cover 14 provided on the bearing 13 are provided.

  The speed reduction mechanism 10 is a wave gear mechanism, and has a wave generator 10a connected to the tip of the rotation shaft 2a of the motor 2 (not shown), a thin metal and is formed into a cup shape and has elasticity, and an opening portion of the cup A flex spline 10b provided with gear teeth (not shown) on the outer surface of 10d, and a circular spline 10c provided with gear teeth (not shown) meshing with the gear teeth of the flex spline 10b on the inner surface. ing.

  The wave generator 10a is composed of an elliptical cam and a ball bearing disposed on the outer periphery of the cam. The inner ring of the ball bearing is fixed to the cam, and the outer ring of the ball bearing is elastically deformed via the ball. The wave generator 10a is fixed to the front end of the rotating shaft 2a supported by a bearing 16 fixed to a housing (not shown) of the motor 2 with a screw 11d. The wave generator 10a has an elliptical shape and is inserted into the flex spline 10b.

  In the flex spline 10b, one end of the rotary shaft 6 is fixed to the bottom 15 by a screw 11a, and the rotary shaft 6 is also rotated when the flex spline 10b is rotated.

  The circular spline 10c is a rigid body formed in a ring shape, and is fixed to the inner surface of the housing 12 by screws 11b. The circular spline 10c has more gear teeth than the gear teeth of the flex spline 10b. Thus, the speed reduction mechanism 10 is accommodated in the housing 12.

  In a state where the wave generator 10a is inserted into the opening 10d of the flex spline 10b, the opening 10d of the flex spline 10b is deformed into an elliptical shape, and the apex in the major axis direction of the opening 10d of the flex spline 10b that is elliptical. And the gear teeth of the circular spline 10c mesh with the gear teeth of the circular spline 10c. In this state, when the wave generator 10a rotates clockwise, the flex spline 10b is elastically deformed, and the position of meshing with the gear teeth of the circular spline 10c moves. When the wave generator 10a makes one rotation, the flex spline 10b is displaced counterclockwise by the position where the gear teeth of the flex spline 10b mesh with the gear teeth of the circular spline 10c compared to the initial position by the difference in gear teeth with the circular spline 10c. Move to. Therefore, even if the wave generator 10a makes one revolution, the flex spline 10b does not make one revolution, and the rotating shaft 6 connected to the flex spline 10b decelerates according to the gear tooth difference, and the reduction ratio of the reduction mechanism 10 is reduced. Decelerate by minutes.

  An oil seal 25 is provided in the space between the rotary shaft 6 and the housing 12 near the bottom 15 of the flex spline 10b. The oil seal 25 is fixed to the housing 12 and is in contact with the rotating shaft 6. The oil seal 25 seals the space between the rotating shaft 6 and the housing 12, and the oil on the speed reduction mechanism 10 side is removed from the housing 12. Prevents splashing inside.

  In this embodiment, the wave gear mechanism is used as the speed reduction mechanism 10, but the speed reduction mechanism 10 is not particularly limited, and another mechanism such as a planetary gear mechanism may be used as the speed reduction mechanism 10.

  The rotating shaft 6 has a cylindrical shape, one end connected to the speed reduction mechanism 10 is accommodated in the housing 12, and the other end projects from the torque detector integrated speed reducer 3 so that a load can be attached. Yes.

  The rotating shaft 6 has a strain-generating portion 6a having a diameter smaller than that of the other portion, and a disc-shaped rod formed on the motor 2 side of the strain-generating portion 6a and protruding from the rotating shaft 6 in a bowl shape. Part 6b. A strain gauge 18 is attached to the strain generating portion 6a. The strain generating part 6a has strength in the longitudinal direction of the rotating shaft 6 and does not deform, but has a diameter smaller than that of the other parts, and therefore deforms in the twisting direction. As a result, the strain gauge 18 is distorted by a torsion (shear strain) generated in the strain generating portion 6a, and a resistance change corresponding to the shear strain amount of the strain gauge 18 is generated.

  A substrate 19 is fixed to the flange portion 6b by a substrate fixing column 20. The substrate 19 is a ring-shaped disk. The substrate 19 includes a first substrate 19a and a second substrate 19b, and a torque detection circuit 29 connected to the strain gauge 18 is provided on the surface of the first substrate 19a. The substrate 19 is preferably circular, but may be rectangular or polygonal.

  The torque detection circuit 29 includes a resistance change detection circuit such as a Wheatstone bridge circuit that detects a resistance change of the strain gauge 18 disposed on the rotating shaft 6, and an AD converter that converts the output of the resistance change detection circuit into a digital signal. A CPU for processing the digital signal, a rectifier circuit, and a stabilization circuit are provided.

  The torque detection circuit 29 can measure the amount of shear strain applied to the strain gauge 18 by detecting the resistance change generated in the strain gauge 18 from the output voltage signal of the resistance change detection circuit converted into a digital signal. Can be calculated.

  The CPU calculates a measured value of torsion torque based on the output voltage signal of the resistance change detection circuit converted into a digital signal, and sends it to the transmitter 27.

  In the case of this embodiment, four strain gauges 18 are attached to the outer peripheral surface of the strain generating portion 6a at intervals of 90 °, and the resistance change detection circuit is a Wheatstone bridge circuit composed of four strain gauges 18. It is. With this configuration, the shear strain generated in the rotating shaft 6 can be reliably detected, and a minute resistance change generated in the strain gauge 18 can be detected, so that the torsion torque can be detected more reliably.

  The number of strain gauges 18 and the configuration of the resistance change detection circuit are preferably as described above, but are not particularly limited.

  On the surface of the second substrate 19b, there is provided a transmission unit 27 that is connected to the torque detection circuit 29 and wirelessly transmits a torsion torque measurement value signal transmitted from the torque detection circuit 29. The transmission unit 27 digitally modulates a signal of a measured value of torsion torque, and emits infrared light in accordance with the digital modulation signal output from the digital modulation circuit to generate the digital modulation signal. And a light emitting element (not shown) such as an LED that converts the light signal.

  The housing substrate 24 fixed to the housing 12 is provided with a receiving unit 28 that receives the optical signal transmitted from the transmitting unit 27 at a position facing the transmitting unit 27, and the transmitting unit 27 and the receiving unit 28. Wireless communication such as infrared communication can be performed between them.

  The receiving unit 28 receives infrared light emitted from the transmitting unit 27 and receives light such as a photodiode that converts an optical signal into an electrical signal (that is, a digital modulation signal before being converted into an optical signal by the transmitting unit 27). An element (not shown) and a digital demodulation circuit (not shown) for extracting a torsion torque measurement value signal from the digital modulation signal converted into an electric signal by digital demodulation.

  The digital demodulation circuit is connected to the wiring 7b (not shown in FIG. 2), and sends a signal corresponding to the measured value of the torsion torque to the motor control device 5.

  The torque detection circuit 29 and the transmission unit 27 are arranged so that the centrifugal force exerted on the torque detection circuit 29 and the transmission unit 27 does not easily affect the rotation shaft 6 when the substrate 19 rotates together with the rotation shaft 6. Electronic components that constitute the transmitter 27 are arranged.

  In the present embodiment, the substrate 19 is composed of two substrates, a first substrate 19a and a second substrate 19b, but the number of substrates is not particularly limited, and is composed of a single substrate. Alternatively, it may be composed of three or more substrates. In particular, it is preferable that the substrate 19 is composed of a single substrate because the length of the rotating shaft 6 can be shortened and the torque detector integrated speed reducer 3 can be reduced in size.

  Further, the rotating shaft 6 is made of a magnetic sheet such as a ferrite sheet, for example, and a secondary core 21a covering the side surface of the rotating shaft 6 and a conductive wire such as a copper wire on the surface of the secondary core 21a. A power receiving unit 21 including a secondary coil 21b formed by winding is provided.

  In the housing substrate 24, a power transmission unit 22 held by a core holder 23 fixed to the housing substrate 24 is disposed at a position facing the power reception unit 21. The power transmission unit 22 is held by a core holder 23 and is made of, for example, a magnetic material such as ferrite, and has two protrusions, a primary side core 22a and a primary side core 22a that are shaped so that the cross-sectional shape is a U-shape. A primary coil 22b formed by winding a conductive wire such as a copper wire is provided therebetween.

  The housing substrate 24 is provided with a switching circuit (not shown) connected to the motor control device 5 (not shown in FIG. 2) via a wiring 7b (not shown in FIG. 2). The switching circuit converts the direct current supplied from the motor control device 5 into an alternating current. The switching circuit is connected to the power transmission unit 22 and outputs the converted alternating current to the power transmission unit 22.

  The power transmission unit 22 causes the supplied AC current to flow through the primary coil 22 b, generates an AC magnetic field in the primary coil 22 b, and induces a current in the secondary coil 21 b of the power reception unit 21. Therefore, the secondary coil 21b can receive electric power from the primary coil 22b in a non-contact manner.

  The power receiving unit 21 supplies the alternating current induced in the secondary coil 21 b to the torque detection circuit 29. The torque detection circuit 29 converts the supplied AC voltage into a DC voltage by a rectifier circuit and a stabilization circuit, and supplies it to a resistance change detection circuit or the like.

  A bearing 13 that rotatably supports the rotating shaft 6 with respect to the housing 12 is provided in the housing 12 via a connection portion 26. The connecting portion 26 has a hole formed at the center thereof, and the flange portion 6b of the rotating shaft 6 is disposed in the hole, and the inner side surface 26a of the hole of the connecting portion 26 faces the flange portion 6b with a predetermined interval. As shown in FIG.

  In the present embodiment, the bearing 13 is a cross roller bearing and includes an outer ring 13a, an inner ring 13b, and a cylindrical roller 13c. The bearing 13 has the outer ring 13a fixed to the connection portion 26 and the inner ring 13b fixed to the flange portion 6b with a screw 11c, so that the rotation shaft 6 can freely rotate with respect to the housing 12. I support it.

  Thus, the bearing 13 supports the rotating shaft on the motor 2 side in the longitudinal direction of the rotating shaft 6 with respect to the strain generating portion 6a. In the present embodiment, the strain gauge 18 is loaded in the longitudinal direction of the rotating shaft 6 rather than the position where the rotating shaft 6 is supported by the bearing 13 provided in the housing 12 that houses a part of the rotating shaft 6 and the speed reduction mechanism 10. Since it is arranged on the other end side to which the screw is connected, it is possible to suppress the stress caused by the fastening of the screw or bolt at the time of assembly from occurring in the strain generating portion 6a to which the strain gauge 18 is attached, and the influence of the stress is affected. It is possible to suppress the strain gauge 18 and torsional torque can be measured more reliably.

  The shaft cover 14 is fixed to the outer ring 13a of the bearing 13 by a screw 11e, and a hole is formed at the center. The hole is formed in such a size that when the shaft cover 14 is fixed to the bearing 13, the inner surface of the hole does not contact the rotating shaft 6.

  In the torque detector integrated speed reducer 3 of the present embodiment, the torque measurement unit 8 includes the strain gauge 18, the torque detection circuit 29, the transmission unit 27, the reception unit 28, the demodulation circuit, the power reception unit 21, and the power transmission unit 22. It consists of

  Next, the motor control device 5 of this embodiment will be described. FIG. 3 is a block diagram 30 showing the motor control device 5. As shown in FIG. 3, the motor control device 5 includes a back drivability control unit 38, a disturbance observer 34 that estimates a disturbance torque of the motor 2, and an acceleration control unit 33.

The motor control device 5 calculates the current command value i _q ^ref based on the torsion torque τ _s measured by the torque measuring unit 8, the position response value θ _m detected by the rotary encoder 4, and the load side torque command value τ ^cmd. calculate. Then, the motor control device 5 inputs the current command value i _q ^ref to the motor 2 to drive the motor 2, and causes the torque generated on the rotating shaft 6 to follow the load side torque command value τ ^cmd .

  Each component of the motor control device 5 shown in FIG. 3 is a classification of the interior of the motor control device 5 for convenience, focusing on the function of controlling the motor 2, and each component can be physically divided. There is no need. The motor control device 5 may be realized by hardware using an LSI or the like, or may be realized by software using a computer program.

In this embodiment, the motor control device 5 inputs the current command value i _q ^ref to the motor 2 and drives the motor 2. However, the motor control device 5 controls the external power supply provided outside the motor control device 5 to control the current command value. A current corresponding to i _q ^ref may be supplied to the motor 2.

  The motor 2 and the torque detector integrated speed reducer 3 vibrate at a predetermined resonance frequency because the rotary shaft 6 has elasticity or the gear teeth of the speed reduction mechanism 10 are elastically coupled. It is a mechanical resonance system. Therefore, since the motor 2 and the torque detector integrated speed reducer 3 can be represented by an approximate model of a two-inertia resonance system, in FIG. 3, for convenience, the motor 2 and the torque detector integrated speed reducer 3 are It is expressed using an approximate model of a two-inertia resonance system. 3 shows a state in which a load 37 is connected to the rotating shaft 6 (not shown in FIG. 3).

Motor 2 in terms of the approximate model of the two-inertia resonant system, current - that converts the current command value i _q ^ref torque value is multiplied by a torque constant K _t the torque converter 2b to the current command value i _q ^ref By subtracting the torque response value τ ^dis of the torque detector-integrated speed reducer 3 from the subtractor 2c, the output torque value generated on the rotating shaft 2a of the motor 2 is equivalently calculated. The torque response value τ ^dis of the torque detector integrated speed reducer 3 means the torque transmitted from the torque detector integrated speed reducer 3 to the motor 2, that is, the disturbance torque of the motor 2.

Further, the motor 2 equivalently calculates the speed response value ω _m that is the rotational speed of the rotating shaft 2a of the motor 2 by converting the output torque value calculated by the subtractor 2c into a speed by the torque-speed converter 2d. To do. The speed response value ω _m can be calculated by multiplying the term 1 / (J _m s + D _m ) in the torque-speed converter 2d shown in FIG. 3 and the output torque value from the subtractor 2c. J _m is the moment of inertia of the motor 2, D _m is the viscous friction of the motor 2, and s is a Laplace operator.

The torque detector integrated speed reducer 3 represented by an approximated model of a two-inertia resonance system is a load that comprehensively includes disturbance torque such as inertia variation and friction of the load 37 connected to the rotating shaft 6 from the torsion torque τ _s. The output torque value generated in the rotating shaft 6 is equivalently calculated by subtracting the torque response value τ _L of 37 by the subtractor 3c.

Further, the torque detector-integrated speed reducer 3 converts the output torque value calculated by the subtractor 2c into a speed by a torque-speed converter 3d, so that the rotational speed of the rotating shaft 6 of the torque detector-integrated speed reducer 3 is converted. the velocity response value omega _L is calculated equivalently. The speed response value ω _L can be calculated by multiplying the term 1 / (J _L s + D _L ) in the torque-speed converter 3d shown in FIG. 3 and the output torque value from the subtractor 3c. J _L is the moment of inertia of the torque detector integrated reduction gear 3, D _L is the viscous friction torque detector integrated reduction gear 3.

In the approximated model of the two-inertia resonance system, the torsion torque τ _s generated in the torque detector-integrated speed reducer 3 is determined between the torsion angle caused by the speed difference between the motor 2 and the load 37 and the motor 2 and the load 37. It is modeled as the product of the spring constant K _s that is determined depending on the mechanical resonance vibrations.

In other words, the speed difference between the motor 2 and the load 37, the deceleration mechanism 10 (FIG velocity response value omega _m by multiplying the reciprocal of the reduction ratio R _g in velocity response value omega _m of the motor 2 at the speed reduction ratio inverter 3a from the converted value in accordance with the reduction ratio of not shown) to 3, it is calculated by subtracting the velocity response value omega _L of the torque detector integrated reduction gear 3 by the subtracter 3b.

The torsion torque τ _s is converted into a torsion angle of the rotating shaft 6 by integrating the speed difference calculated by the subtractor 3 b by an integrator 3 f having a spring constant K _s as a gain, and the torsion angle is converted into a spring constant. is the equivalent to the calculated multiplying the K _s.

In the approximation model of the two-inertia resonance system, the torsion torque τ _s calculated in this way is added to the subtractor 3c, and this torsion torque τ _s is multiplied by the reciprocal of the reduction ratio R _g by the reduction ratio inverse converter 3g. The value τ _s / R _g calculated in this way is expressed as a torque response value τ ^dis as if it was added to the subtractor 2 c of the motor 2.

In FIG. 3, the motor 2 outputs a position response value θ _m of the motor 2 that is a value obtained by integrating the speed response value ω _m by the integrator 2e, and the torque detector integrated speed reducer 3 outputs the speed response value. indicates to output a position response value theta _L of the load 37 is a value obtained by integrating the omega _L in integrator 3e.

Actually, the torsion torque τ _s physically generated in the rotating shaft 6 is measured by the torque measuring unit 8. In the block diagram 30 shown in FIG. 3, an approximation model of a two-inertia resonance system is applied. Therefore, the torsion torque τ _s calculated as described above is represented as being measured by the torque measuring unit 8.

The back drivability control unit 38 calculates an acceleration command value based on the measured value of the torsion torque τ _s measured by the torque measurement unit 8 and the load side torque command value τ ^cmd, and the torque generated on the rotating shaft 6 is calculated. While following the load side torque command value τ ^cmd , the resonance ratio of the motor 2 and the torque detector integrated speed reducer 3 is controlled to suppress the vibration of the motor 2 and the torque detector integrated speed reducer 3.

  In the case of the present embodiment, the back drivability control unit 38 includes a load side torque control element 31 that controls the torque generated in the rotating shaft 6 and a resonance ratio control element 32 that controls the resonance ratio.

The load-side torque control element 31 is based on the measured value of the torsion torque τ _s measured by the torque measuring unit 8 and the load-side torque command value τ ^cmd, and the load-side acceleration command value ^~ θ ^{·· ref} Is calculated. Here, “ ^˜ ” means a numerical value on the load side, and “ ^·· ” means a second-order differentiation. In the present embodiment, the load side torque control element 31 performs I-PD control based on the measured value of the torsion torque τ _s and the load side torque command value τ ^cmd, and the torque generated on the rotating shaft 6 is the load side torque command. It follows the value τ ^cmd .

Specifically, the load-side torque control element 31 is provided with a measurement of the torsional torque tau _s from the load torque command value tau ^cmd subtracted by the subtractor 31a, the output of the subtractor 31a, an integral gain K _i integration Input to the controller 31b.

Further load torque control element 31, the measured value of the torsional torque tau _s, and input to the pseudo differentiator 31d comprises a proportional controller 31c having a proportional gain K _p of the differential gain K _d, the proportional controller 31c The adder 31e adds the output and the output of the pseudo-differentiator 31d.

The load side torque control element 31 subtracts the output of the adder 31e from the output of the integration controller 31b by the subtractor 31f, and calculates the load side acceleration command value ^~ θ ^{·· ref} . As described above, in the motor control device 5, the torsion torque τ _s is fed back to the load side torque command value τ ^cmd by the load side torque control element 31, and the disturbance torque applied to the rotating shaft 6 through the load 37 is compensated.

The load side torque control element 31 calculates the load side acceleration command value ^to θ ^{·· ref} based on the load side torque command value τ ^cmd and the measured value of the torsion torque τ _s measured by the torque measuring unit 8. As long as it is not limited, it may have only one controller such as a proportional controller and an integral control controller, or may be a combination of two controllers such as a proportional integral controller and a proportional derivative controller. .

The load-side torque command value tau ^cmd may be input from the outside to the motor control unit 5 stores the advance load torque instruction value tau ^cmd in a storage medium provided in the motor control unit 5, the The stored load side torque command value τ ^cmd may be used.

The resonance ratio control element 32 corrects the acceleration command value input from the load side torque control element 31 based on the measured value of the torsion torque τ _s measured by the torque measuring unit 8. Resonance ratio control element 32, the measured value of the torsional torque tau _s, torque comprises a gain K _r - input to the acceleration transducer 32b gain K _r by multiplying the torsion torque tau _s and converts the torque to acceleration.

Resonance ratio control element 32 from the load side acceleration command value ^~ theta ^{· · ref,} the torque - by subtracting the output of the acceleration transducer 32b subtractor 32a, corrects the load side acceleration command value ^~ theta ^{· · ref} . In this way, the resonance ratio control element 32 controls the resonance ratio of the system including the motor 2 and the torque detector-integrated speed reducer 3, so that the motor control device 5 has the motor 2 and torque detector-integrated speed reducer. 3 is suppressed. The resonance ratio is about 2.236.

The back-drivability control unit 38, by setting the proportional gain K _p of the proportional controller 31c as appropriate, even if the gain K _r is set to 0, the motor 2 and the torque detector by controlling the resonance ratio The vibration of the integrated speed reducer 3 can be suppressed. This vibration of the motor 2 and the torque detector integrated reduction gear 3, the value of the sum K _{p +} K _r of the proportional gain K _p of the gain K _r and proportional controller 31c is equal constant at a predetermined value, K it is suitably change the value of _r and K _p is thereby inhibited.

Since that the gain K _r is set to 0 is equivalent to that it does not have a resonance ratio control element 32, the back drivability control unit 38, depending on the value of the proportional gain K _p, the resonance ratio control Element 32 can be omitted.

Similarly, the back drivability control unit 38, the value of the gain _{K r} is next proportional gain _{K p} is 0, can be omitted proportional controller 31c.

Reduction ratio converter 36 has a reduction ratio R _g as a gain, converts the corrected by the resonance ratio control element 32 the load-side acceleration command value ^~ theta ^{· · ref} of the motor side acceleration command value theta ^{· · ref} . When the reduction ratio of the reduction mechanism 10 is 1, it is not necessary to provide the reduction ratio converter 36 and the reduction ratio inverse converters 3a and 3g. In this case, the load side acceleration command value ^to θ ^{·· ref} becomes the motor side acceleration command value θ ^{·· ref} as it is.

The disturbance observer 34 is based on the current command value i _q ^ref that is an input to the motor 2 and the output from the motor 2 and the position response value θ _m detected by the rotary encoder 4. Estimated value ^ ^τdis is calculated. Here, “^” means an estimated value. In the present embodiment, the disturbance observer 34 estimates the disturbance torque based on the current command value i _q ^ref and the position response value θ _m . However, the present invention is not limited to this, and the current command value i _The disturbance torque may be estimated based on _q ^ref and the speed response value ω _m of the motor 2.

The acceleration control unit 33 inputs the motor side acceleration command value θ ^{·· ref} to an acceleration-current converter 33a having a gain J _mn / K _tn and converts the acceleration into a current. Further, the acceleration control unit 33 inputs the estimated value τ ^dis of the disturbance torque of the motor 2 to a torque-current converter 33c having a gain 1 / K _tn , and converts the torque into a current.

The acceleration control unit 33 adds the output of the acceleration-current converter 33a and the output of the torque-current converter 33c by the adder 33b, and calculates the current command value i _q ^ref . Here, K _tn is a nominal value of the torque constant, and J _mn is a nominal value of the moment of inertia of the motor 2.

As described above, in the motor control device 5, the estimated value ^ ^τdis of the disturbance torque of the motor 2 calculated by the disturbance observer 34 based on the input and output of the motor 2 by the acceleration control unit 33 is the current command value i _q ^ref. Thus, the dynamic friction of the motor 2 is compensated.

Thus, the motor control device 5 inputs the current command value i _q ^ref calculated by the acceleration control unit 33 to the motor 2 so that the torque applied to the load 37 follows the load-side torque command value τ ^cmd. Can be controlled.

(2) Operation and Effect In the above configuration, the motor control device 5 according to the present embodiment is a torsional torque that is a disturbance torque of the motor 2 that mechanically transmits the driving force to the load according to the load side torque command value τ ^cmd. Based on the measured value of τ _s and the load side torque command value τ ^cmd , a back drivability control unit 38 for calculating a load side acceleration command value ^~ θ ^{·· ref} as an acceleration command value is provided. .

Further, the motor control device 5 estimates the disturbance torque of the motor 2 based on the current command value i _q ^ref input to the motor 2 and the position response value θ _m detected by the rotary encoder 4, and the disturbance torque of the motor 2. The disturbance observer 34 for outputting the estimated value ^ τ ^dis of the acceleration and the acceleration command value calculated by the back drivability control unit 38 and converted into the motor side acceleration command value θ ^{·· ref} by the reduction ratio converter and the disturbance observer And an acceleration control unit 33 that calculates a current command value i _q ^ref to be input to the motor 2 based on the estimated value τ ^dis of the disturbance torque of the motor 2 that is output.

Therefore, in the motor control device 5 of the present embodiment, the back drivability control unit 38 feeds back the measured value of the torsional torque τ _s actually measured by the torque measuring unit 8 to the load side torque command value τ ^cmd so that the disturbance torque And the vibration ratio can be suppressed by controlling the resonance ratio of the motor 2 and the torque detector integrated speed reducer 3, and the disturbance torque of the motor 2 calculated by the disturbance observer 34 based on the input and output of the motor 2. The estimated value ^ τ ^dis can be fed back to the current command value i _q ^ref by the acceleration control unit 33 to compensate for the dynamic friction of the motor 2, so that disturbance torque can be compensated even when aging occurs, and stable torque control is possible. Can be realized.

(3) Other Embodiments The present invention is not limited to the above-described embodiments, and various modifications can be made within the scope of the gist of the present invention.

  In the above embodiment, the power receiving unit 21 is provided on the rotating shaft 6 of the torque detector integrated speed reducer 3, and the power transmitting unit 22 held by the core holder 23 fixed to the casing substrate 24 facing the power receiving unit 21 is provided. However, the present invention is not limited to this.

  For example, the power receiving unit 21 may be provided on the outer surface of the flex spline 10b as in the torque detector integrated reduction device 301 shown in FIG.

  In this case, in the torque detector integrated reduction device 301, the sheet-like secondary core 21a is disposed so as to cover the outer surface of the flex spline 10b of the reduction mechanism 10, and the secondary coil 21b is disposed on the secondary core 21a. Is formed, and the power receiving unit 21 is provided.

  In such a torque detector-integrated speed reducer 301, the power receiving unit 21 is provided on the outer side surface of the flex spline 10b. Therefore, the torque detector according to the embodiment in which the power receiving unit 21 is provided on the side surface of the rotating shaft 6. The housing 1201 and the rotating shaft 601 can be made shorter than the integrated speed reducer 301, and the size can be reduced.

  Further, like the torque detector-integrated speed reducer 302 shown in FIG. 5 in which the same components as those in FIG. 2 are given the same reference numerals, the strain is generated on the rotating shaft 602 and the strain gauge 18 is adhered. The power receiving unit 21 may be provided on the outer surface of the cylindrical member 42 disposed so as to surround the outer periphery of the unit 602a.

  In this case, the rotating shaft 602 includes a strain generating portion 602a and two flange portions, a first flange portion 602b and a second flange portion 602c. The first flange portion 602b is provided at the end of the strain-generating portion 602a on the motor 2 side, and the cylindrical member 42 is attached thereto. The second flange portion 602c is provided at the end of the strain generating portion 602a on the distal end side of the rotating shaft 602.

  The cylindrical member 42 is formed in a cylindrical shape, and has an inner diameter that is approximately the same as the outer diameter of the flange portion 602b so as to be fitted to the flange portion 602b. The cylindrical member 42 has the flange portion 602b inserted therein until one end comes into contact with the convex portion 602d formed on the motor 2 side end of the flange portion 602b. The mounting position of the cylindrical member 42 is fixed by the convex portion 602d, and is fixed to the flange portion 602b by the screw 11f. The cylindrical member 42 is disposed so as to surround the outer periphery of the strain generating portion 602a to which the strain gauge 18 is attached.

  In the power receiving unit 21, a sheet-like secondary core 21a is disposed so as to cover the outer peripheral surface of the cylindrical member 42, and the secondary coil 21b is wound on the secondary core 21a, whereby the cylindrical member 42 is wound. It is formed on the outer peripheral surface.

  In such a torque detector-integrated speed reducer 302, the power receiving unit 21 is provided on the outer peripheral surface of the cylindrical member 42 attached to the flange portion 602b so as to surround the strain generating portion 602a. The housing 1202 and the rotating shaft 602 can be made shorter and smaller than the torque detector-integrated speed reducer 3 of the embodiment in which the power receiving unit 21 is directly provided on a part of the surface.

  Further, in the torque detector-integrated reduction device 302, since the substrate 19 is also disposed so as to surround the outer periphery of the strain generating portion 602a, the casing 1202 and the rotating shaft 602 can be further shortened, and further miniaturized. it can.

  As described above, it is desirable that both the cylindrical member 42 and the substrate 19 are arranged so as to surround the outer periphery of the strain-generating portion 602a. However, at least one of the cylindrical member 42 and the substrate 19 has an outer periphery of the strain-generating portion 602a. If it arrange | positions so that may be enclosed, the torque detector integrated reduction gear 3 can be reduced in size.

  It should be noted that the cylindrical member 42 and the substrate 19 are preferably formed in a cylindrical shape or a donut shape and surround the outer periphery of the strain-generating portion 602a without a single round, but the cylindrical member 42 and the substrate 19 are partially missing. Thus, a part of the outer periphery of the strain generating portion 602a may not be covered.

  Further, the torque detector integrated reduction device 302 includes a radial deep groove ball bearing as a bearing 1302 that rotatably supports the rotating shaft 602 with respect to the housing 1202. The bearing 1302 includes an outer ring 1302a fixed to the connection portion 2602 fixed to the housing 1202, an inner ring 1302b fixed to the second flange portion 602c of the rotating shaft 602, and a ball disposed between the outer ring 1302a and the inner ring 1302b. 1302c. The bearing 1302 is covered with a shaft cover 1402 attached to the housing 1202.

  Further, the torque detector integrated speed reducer 302 is a radial deep groove ball bearing, and includes a bearing 41 provided in the vicinity of the speed reduction mechanism 10. The torque detector-integrated speed reducer 302 is supported by a bearing 41 so that the rotary shaft 602 can rotate with respect to the housing 1202. The bearing 41 includes an outer ring 41 a fixed to the housing 1202, an inner ring 41 b fixed to one flange 602 b of the rotating shaft 602, and a ball 41 c disposed between the outer ring 41 a and the inner ring 41 b. As described above, the torque detector-integrated speed reducer 302 supports the rotating shaft 602 by the two bearings 1302 and 41, and thus can support the rotating shaft 602 more reliably.

  Further, the bearing 41 is provided with a seal member (not shown) to prevent oil on the speed reduction mechanism 10 side from scattering into the housing 1202.

  As described above, in the present invention, a bearing other than the cross roller bearing may be used as a bearing that rotatably supports the rotating shaft with respect to the casing, and the rotating shaft 6 may be formed using two or more bearings. May be supported.

DESCRIPTION OF SYMBOLS 1 Motor apparatus 2 Motor 3 Torque detector integrated reduction gear 5 Motor control apparatus 6 Rotating shaft 8 Torque measurement part 10 Deceleration mechanism 31 Load side torque control element 32 Resonance ratio control element 33 Acceleration control part 34 Disturbance observer 38 Back drivability Control unit

Claims (9)

Back drivability that calculates an acceleration command value based on a measured value of torsion torque that is a disturbance torque of a motor that mechanically transmits driving force to a load according to the load side torque command value and the load side torque command value A control unit;
A disturbance observer for estimating a disturbance torque of the motor;
An acceleration control unit that calculates a current command value to be input to the motor based on the acceleration command value calculated by the back drivability control unit and an estimated value of the disturbance torque of the motor output from the disturbance observer. A motor control device comprising: The back drivability control unit
A load-side torque control element that calculates the acceleration command value based on the measured value of the torsional torque and the load-side torque command value;
The motor control device according to claim 1, further comprising: a resonance ratio control element that corrects the acceleration command value based on a measured value of the torsional torque. The motor control device according to claim 1 or 2,
A torque measuring unit for measuring the torsion torque,
The torque measuring unit is
One end is connected to the motor via a speed reduction mechanism, and the other end to which the load is connected is a strain gauge disposed on a rotating shaft that generates torque according to the load side torque command value;
And a torque detection circuit that detects a change in resistance of the strain gauge and calculates the torsion torque from the detected change in resistance. The strain gauge is disposed on the other end side in the longitudinal direction of the rotary shaft with respect to a position where the rotary shaft is supported by a bearing provided in a housing for housing a part of the rotary shaft and the speed reduction mechanism. The motor device according to claim 3. The torque measuring unit is
A primary coil fixed to a housing that houses a part of the rotating shaft and the speed reduction mechanism;
5. The motor device according to claim 3, further comprising: a secondary coil that is provided in the speed reduction mechanism so as to face the primary coil and receives electric power from the primary coil in a non-contact manner. The torque measuring unit is
A primary coil fixed to a housing that houses a part of the rotating shaft and the speed reduction mechanism;
A cylindrical member mounted on the rotating shaft, provided so as to face the primary coil, and a secondary coil that receives power from the primary coil in a non-contact manner;
The torque detection circuit is provided on a substrate fixed to the rotating shaft;
5. The motor device according to claim 3, wherein at least one of the cylindrical member and the substrate is disposed so as to surround an outer periphery of a strain generating portion to which the strain gauge is attached. The motor that outputs torque according to the input current command value;
A speed reduction mechanism connected to the motor;
The motor device according to claim 3, further comprising: the rotating shaft connected to the speed reduction mechanism. An acceleration command value is calculated based on a measured value of torsion torque that is a disturbance torque of a motor that mechanically transmits driving force to a load according to a load side torque command value, and the load side torque command value,
A motor control method, comprising: calculating a current command value to be input to the motor based on the acceleration command value and an estimated value of disturbance torque of the motor estimated by a disturbance observer. The motor control method according to claim 8, wherein the acceleration command value is corrected based on a measured value of the torsion torque.

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