JP2022092761A - Motor control unit and motor control method, imaging apparatus, and control system - Google Patents

Abstract

To provide a motor control unit and a motor control method that can perform control based on torque calculation with higher accuracy.SOLUTION: A motor control unit performs drive control of a part to be driven through reduction gears with electric motors 11, 21. A first control unit 221 performs drive control of the first electric motor 11 by using a first command value. A second control unit 222 performs drive control of the second electric motor 21 by using a second command value different from the first command value. In position control of the part to be driven 30, a load torque calculation unit 400 calculates a helix angle generated in the reduction gears based on information on the positions of the first and second electric motors 11, 21 and information on the position of the part to be driven 30, and calculates torque generated in the reduction gears from the helix angle and a rigidity value of the reduction gears.SELECTED DRAWING: Figure 2

Description

The present invention relates to a control technique for driving one driven body by controlling a plurality of motors.

In the fields of commercial equipment and industrial equipment, drive actuators are required to have advanced control such as high-precision drive control and torque control. For example, an electrically driven pan head installed outdoors is capable of turning. In this case, it is necessary to suppress the vibration generated by being affected by the disturbance torque such as wind to prevent the quality of the image captured by the camera mounted on the electrically driven pan head from being affected.

Further, in industrial robots, advanced product assembly and the like are required, and it is necessary to detect and control a minute torque generated at the time of assembly. In order to suppress the influence of disturbance torque and realize highly accurate torque control, it is required to perform drive control after accurately measuring the load torque generated on the drive shaft. As a method of measuring the load torque generated on the drive shaft, there are a method of measuring from the drive current of the motor and a method of measuring with a torque sensor arranged in the output stage of the speed reducer. Further, there is a method of measuring from the helix angle generated inside the reducer, which is obtained from the encoder arranged in the motor and the encoder arranged in the output stage of the reducer (see Patent Document 1). However, in any torque measurement method, if the reducer provided on the drive shaft has backlash, the torque measurement accuracy or torque control accuracy may decrease due to the influence of the backlash unless sufficient measures are taken. There is sex.

Japanese Unexamined Patent Publication No. 2015-206747

In the method disclosed in Patent Document 1, the amount of backlash generated in the speed reducer is specified in advance, and the helix angle when calculating the load torque is corrected, so that the torque measurement accuracy can be improved. However, since the backlash amount has a hysteresis characteristic, it is not possible to calculate an accurate torque by calculating the torque with the backlash amount as a fixed value. Further, even if the torque calculation for correcting the backlash amount is possible, the physical backlash itself of the reducer is not suppressed. Therefore, it is difficult to perform minute torque control or the like.
An object of the present invention is to provide a motor control device and a motor control method capable of controlling based on more accurate torque calculation.

The device of one embodiment of the present invention is a motor control device that controls the drive of the driven unit by a plurality of motors via a speed reducer, and the drive control of the first motor is performed by using the first command value. A second control means for performing drive control of the second motor using a second command value different from the first command value, and a position of the first motor. Information, information on the position of the second motor, and information on the position of the driven unit are acquired, the twist angle generated in the speed reducer is calculated, and the twist angle and the rigidity value of the speed reducer are used to calculate the twist angle. A calculation means for calculating the torque generated in the speed reducer is provided.

INDUSTRIAL APPLICABILITY According to the present invention, it is possible to provide a motor control device and a motor control method capable of controlling based on more accurate torque calculation.

It is a perspective view which shows the outline of the drive device of 1st Embodiment. It is a control block diagram which shows the motor control system of 1st Embodiment. It is a flowchart explaining the torque measurement process of 1st Embodiment. It is a graph which shows the measurement result of the driven part torque of 1st Embodiment. It is a control block diagram which shows the motor control system of 2nd Embodiment. It is a control block diagram which shows the motor control system of 3rd Embodiment.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In each embodiment and drawing, the same member is given the same reference number to avoid duplicate explanations. The motor control device of the embodiment is applied to, for example, an electric drive platform of an image pickup device, and can be used for change control of an image pickup direction. The present invention can be applied to various motor control devices capable of controlling the drive of a driven unit by a plurality of motors via a speed reducer.

[First Embodiment]
FIG. 1 is a perspective view schematically showing the configuration of the drive device 100 of the present embodiment. The drive device 100 includes a first motor unit 10, a second motor unit 20, and a driven unit 30.

The first motor unit 10 includes an electric motor 11, a motor driver 12 for driving the electric motor 11, a motor position detector 13, and a first gear 14. The motor position detector 13 detects the position of the electric motor 11. The information on the position of the electric motor 11 detected by the motor position detector 13 is used for feedback control as the position information (denoted as P _m1 ) of the first motor unit 10. The first gear 14 is a power transmission member that transmits the driving force of the electric motor 11 to the driven portion 30.

The second motor unit 20 includes an electric motor 21, a motor driver 22 for driving the electric motor 21, a motor position detector 23, and a second gear 24. The motor position detector 23 detects the position of the electric motor 21. The information on the position of the electric motor 21 detected by the motor position detector 23 is used for feedback control as the position information (denoted as P _m2 ) of the second motor unit 20. The second gear 24 is a power transmission member that transmits the driving force of the electric motor 21 to the driven portion 30.

The driven unit 30 has a third gear 31, an output shaft 32, and a machine position detection sensor 33. The third gear 31 is driven by the torque transmitted from the first gear 14 and the second gear 24. The output shaft 32 is a shaft member fixed to the third gear 31. The machine position detection sensor 33 constitutes a detection unit that measures the position of the driven unit 30. For example, the mechanical position detection sensor 33 is an optical encoder and has a scale 34 and a detector 35 arranged to face the scale 34. The scale 34 is fixed to the output shaft 32, and the detector 35 is fixed to a base (not shown). With such a configuration, the machine position detection sensor 33 can directly detect the position of the driven unit 30. The machine position detection sensor 33 is not limited to the optical encoder, and a magnetic or capacitive encoder can be used.

The drive device 100 is provided with a main body base (not shown). The main body base has a role of fixing the first motor unit 10 and the second motor unit 20 and rotatably supporting the driven unit 30. Further, a controller (FIG. 2: 200) described later is connected to the drive device 100. The controller 200 controls the drive of the first and second motor units 10 and 20, and also controls the driven body (load) attached to the output shaft 32 so that it can operate at a desired position and speed. do.

In this embodiment, an example in which gears are provided as a speed reducer in the first and second motor units 10 and 20 and the driven unit 30 is shown. Another embodiment is to add gears to the torque transmission path between the first and second motor units 10 and 20 and the driven unit 30 in order to obtain a high reduction ratio. As the number of gears increases, the play due to the gap between the gears increases and the amount of backlash increases. The backlash is a gap at the meshing point between the gears constituting the speed reducer. A backlash amount is intentionally provided in order to rotate the gear smoothly. In the present embodiment, by enabling the control of backlash suppression, it is possible to suppress the influence of backlash regardless of the amount of backlash. Therefore, it is possible to design a reduction ratio with a high degree of freedom without considering the deterioration of performance due to backlash.

Next, a method of measuring the torque of the driven portion in the drive device 100, that is, the load torque applied to the reducer output shaft will be described. FIG. 2 is a control block diagram showing a motor control system of the present embodiment. The motor control system 1 includes a drive device 100, a controller 200 that controls the drive device 100, and a load torque calculation unit 400.

The position teaching data 300 is data on the drive target position of the driven unit 30, and is acquired from the input device. The input device is a teaching pendant, a personal computer (PC), or the like, and the setting operation is performed by the operator who uses the input device.

The controller 200 has a track generation unit 210, a first motor control unit 221, a second motor control unit 222, a backlash suppression command calculation unit 230, and a control command setting unit 240. The controller 200 controls the driven unit 30 so that it can operate at a desired position and speed based on the acquired position teaching data 300.
The orbit generation unit 210 performs the following calculation using the position teaching data 300.
-Calculation of the position trajectory (denoted as Pos _ref ) in the driven unit 30.
-Calculation of the velocity trajectory (denoted as Vel _ref ) in the driven unit 30.
-Calculation of the drive direction (denoted as Dir), which is a parameter for setting the drive direction of the driven unit 30.
Here, the deviation between the position orbit Pos _ref and the position P _m1 of the first motor unit 10 is referred to as P _df1 , and the deviation between the position orbit Pos _ref and the position P _m2 of the second motor unit 20 is referred to as P _df2 . write. The subtraction unit DEC1 calculates the deviation P _df1 and the subtraction unit DEC2 calculates the deviation P _df2 . The deviation P _df1 is input to the first motor control unit 221 and the deviation P _df2 is input to the second motor control unit 222. Further, the velocity trajectory Vel _ref is input from the trajectory generation unit 210 to the backlash suppression command calculation unit 230. The drive direction Dir is input from the track generation unit 210 to the control command setting unit 240, and is used for switching the control command value according to the drive direction Dir.

In the following, for the sake of simplicity, the position P _m1 of the motor unit 10 and the position P _m2 of the motor unit 20 are the positions of the driven unit 30 (with the driven unit position PL ₎ in consideration of the reduction ratio of the speed reducer. It is assumed that the conversion has been performed so that (described) becomes the standard.

The first motor control unit 221 inputs the deviation P _df1 and outputs the first control command value (denoted as _CFB1 ). Feedback control is performed so that the deviation P _df1 is suppressed, and the control command value C _FB1 of the first motor unit 10 is output. Further, the second motor control unit 222 takes the deviation P _df2 as an input and outputs the second control command value (denoted as _CFB2 ). Feedback control is performed so that the deviation P _df2 is suppressed, and the control command value C _FB2 of the second motor unit 20 is output. For example, feedback control is general PID control, and arithmetic processing that combines proportionality, integration, and differentiation with respect to deviation is executed.

The backlash suppression command calculation unit 230 generates a backlash suppression command value (denoted as _CBL , hereinafter also simply referred to as a suppression command value). The suppression command value C _BL is a command value for causing a predetermined difference between the control command value of the first motor unit 10 and the control command value of the second motor unit 20. By providing the backlash suppression command calculation unit 230 and setting the suppression command value C _BL , it is possible to realize a state in which both the first gear 14 and the second gear 24 are in contact with the third gear 31. It is possible to reduce the play due to the gap between the gears constituting the speed reducer. As a result, when a load torque is applied to the output shaft 32 of the driven unit 30, it is possible to suppress a decrease in torque measurement accuracy due to the backlash of the reducer.

The suppression command value C _BL calculated by the backlash suppression command calculation unit 230 can be a fixed value or a variable value. For example, as a variable value, a value depending on the position orbit Pos _ref or a value depending on the velocity orbit or acceleration orbit calculated from the position orbit Pos _ref is used. If it is not necessary to suppress the backlash, the value of the suppression command value C _BL is set to zero. The backlash suppression command calculation unit 230 outputs the suppression command value C _BL to the control command setting unit 240.

The control command setting unit 240 acquires the drive direction Dir, the control command values C _FB1 and C _FB2 of each motor, and the backlash suppression command value C _BL . The control command setting unit 240 determines a driver command value (denoted as V _PWM1 ) for the first motor unit 10 and a driver command value (denoted as V _PWM2 ) for the second motor unit 20. That is, the control command setting unit 240 determines that any one of the three input command values C _FB1 , C _FB2 , and C _BL is set as the driver command values V _PWM1 and V _PWM2 from the drive direction Dir. For example, in the case of forward rotation drive, the control command value C _FB1 of the first motor is set as the driver command value V _PWM1 to the first motor unit 10, and the suppression command value C _BL is set as the driver command to the second motor unit 20. Drive control is performed as the value V _PWM2 . In the case of reverse drive, the suppression command value C _BL is set as the driver command value V _PWM1 for the first motor unit 10, and the control command value C _FB2 for the second motor is set as the driver command value for the second motor unit 20. Drive control is performed as V _PWM2 . This makes it possible to perform drive control while stably suppressing backlash generated in the reducer even when the drive direction is switched.

The controller 200 drives the driven unit 30 by controlling the first motor unit 10 and the second motor unit 20 using the driver command values V _PWM1 and V _PWM2 . Specifically, the driver command values V _PWM1 and V _PWM2 output by the controller 200 are input to the motor drivers 12 and 22, respectively. The motor driver 12 drives the electric motor 11 according to a method of controlling the drive voltage of the motor by pulse width modulation control or the like. Similarly, the motor driver 22 drives the electric motor 21.

The position P _m1 of the first motor unit 10 detected by the motor position detector 13 is input to the subtraction unit DEC1 in the controller 200. The subtraction unit DEC1 calculates the deviation P _df1 and outputs it to the first motor control unit 221. Further, the position _Pm2 of the second motor unit 20 detected by the motor position detector 23 is input to the subtraction unit DEC2 in the controller 200. The subtraction unit DEC2 calculates the deviation P _df2 and outputs it to the second motor control unit 222. In this embodiment, an example of a feedback loop control system in which a position feedback configuration is implemented has been described. In addition, the present invention can be applied to an embodiment of a minor loop control system in which a speed feedback configuration and a current feedback configuration are implemented.

The load torque calculation unit 400 calculates the torque of the driven unit applied to the driven unit 30 from the outside based on the driving result of the driving device 100. The load torque calculation unit 400 includes a torque calculation unit 410 and an internal torque storage unit 420.

The torque calculation unit 410 has a position P _m1 of the first motor unit 10, a position P _m2 of the second motor unit 20, and a driven unit position _PL detected by the machine position detection sensor 33 of the driven unit 30. And get. The torque calculation unit 410 calculates the helix angle (denoted as dθ) inside the speed reducer from the position of each motor unit and the position of the driven unit. Further, the torque calculation unit 410 calculates the torque generated in the speed reducer by multiplying the rigidity value of the speed reducer separately determined by the helix angle dθ. In the present embodiment, in order to stably realize the helix angle detection, the calculation method of the helix angle is switched by the drive direction Dir. For example, in the case of forward rotation drive, the first calculation formula "dθ = (P _L -P _m1 )-(P _m2 -P _m1 )" is used, and in the case of reverse rotation drive, the second calculation formula "dθ = (. " _{PL-P m2)-(P m1-P m2 ) " is} used.

The internal torque storage unit 420 includes a memory and stores data (torque calculation table data) such as friction torque generated inside the reducer. For the torque calculated by the torque calculation unit 410, a torque value including the driven unit torque TL, which is the load torque applied from the outside to the driven unit 30, and the torque generated inside the reducer is calculated. .. In order to detect the driven unit torque TL, it is necessary to remove the influence of the torque generated inside the reducer stored in the internal torque storage unit 420. That is, the subtraction unit DEC3 performs a process of subtracting the torque generated inside the reducer stored in the internal torque storage unit 420 from the output of the torque calculation unit 410, and outputs the driven unit torque TL.

The timing for storing the torque generated inside the speed reducer in the internal torque storage unit 420 is, for example, at the time of product shipment. Alternatively, it may be at any timing. In the case of the embodiment in which the torque generated inside the reducer is measured and stored at an arbitrary timing, it is possible to cope with the change in the internally generated torque due to the change with time of the drive device 100.

FIG. 3 is a flowchart illustrating a torque measurement process. Hereinafter, the case of forward rotation drive will be described. Drive control is performed by setting the control command value C _FB1 of the first motor as the driver command value V _PWM1 to the first motor unit 10 and the backlash suppression command value C _BL as the driver command value V _PWM2 to the second motor unit 20. Will be done.

First, in S1, the controller 200 controls the drive device 100 based on the position teaching data 300, and the motor is driven. At this time, since the backlash suppression is not performed, the backlash suppression command value C _BL is set to zero.

In the next S2, the controller 200 executes a determination process of whether or not to execute the torque measurement. Whether or not the torque measurement is executed is performed according to a manual selection by the user operation, or is performed by an automatic selection based on the position teaching data 300 or the information accompanying the position teaching data 300. If it is determined in S2 that torque measurement is to be performed, the process proceeds to S3, and if it is determined that torque measurement is not performed, the process proceeds to S6.

In S3, the controller 200 sets the backlash suppression command value C _BL to a predetermined value, and performs drive control so as to suppress the backlash generated inside the reducer. For example, the electric motor 11 is used as a main motor for position control, and the electric motor 21 is used as a _submotor for suppressing backlash, and drive control is performed with a torque difference based on the suppression command value CBL between the two motors.

In S4, the torque calculation unit 410 sets the helix angle dθ generated inside the reducer to the position P _m1 of the first motor unit 10, the position P _m2 of the second motor unit 20, and the driven unit position P. Calculated from _L. In the case of forward rotation drive, the helix angle dθ is calculated using the first calculation formula “dθ ₌ (PL − P _m1 ) − (P _m2 -P _m1 )”.

Next, in S5, the load torque calculation unit 400 calculates the driven unit torque, which is the load torque applied to the speed reducer. By multiplying the helix angle dθ acquired in S4 by the rigidity value of the speed reducer separately determined, the torque generated by the speed reducer can be obtained. However, since the calculated torque generated by the reducer includes the internal friction torque generated due to the friction of the reducer, the load torque acting on the reducer is obtained as it is. It is not possible. In the present embodiment, the subtraction unit DEC3 subtracts the torque generated inside the reducer stored in the internal torque storage unit 420 from the torque calculated by the torque calculation unit 410, so that the load torque applied to the reducer is applied. The driven unit torque TL is obtained.

In S6, the controller 200 executes the drive end determination process. If it is determined that the drive is not terminated, the process returns to S1 and the process is continued. If it is determined in S6 that the drive is terminated, the series of operations is terminated.

When the controller 200 switches the drive direction with respect to the rotation direction of the driven unit 30 (switching from the forward rotation direction to the reverse rotation direction or switching in the opposite direction), the controller 200 is for suppressing backlash, which is one of the two motors. It controls the drive of the motor. Further, when the backlash amount of the speed reducer acquired in advance from the storage unit or the like is larger than a predetermined threshold value, the controller 200 controls the drive of the backlash suppressing motor.

In the present embodiment, by the above operation control, it is possible to calculate the helix angle generated in the speed reducer while suppressing the backlash generated in the speed reducer. That is, it is possible to detect minute torque changes with high accuracy, which was not possible due to backlash in the prior art.

FIG. 4 is a graph showing the measurement result of the driven unit torque. An example is shown in a case where a predetermined load is set on the driven portion 30 of the drive device 100 and the drive is driven so that a load in the vertical direction is applied. In FIGS. 4A to 4C, the horizontal axis represents the position of the driven portion, and the vertical axis represents the torque.

FIG. 4A is a diagram showing the relationship between the position of the driven portion and the torque measurement value obtained from the helix angle calculated in S4 of FIG. The graph shows the measurement result including the internal friction torque caused by the friction of the reducer. Without correction using the data of the internal torque storage unit 420, it is not possible to obtain only the driven unit torque TL.

FIG. 4B is a diagram showing the relationship between the position of the driven unit stored in the internal torque storage unit 420 and the torque generated inside the reducer. It can be seen that vibration appears periodically according to the number of teeth of the reducer.

FIG. 4C is a diagram showing a torque calculation result calculated in S5 of FIG. By subtracting the torque generated inside the reducer shown in FIG. 4 (B) from the torque calculation result shown in FIG. 4 (A), the driven unit torque TL acting on the driven unit 30 is obtained. It becomes possible. However, the torque calculation result is processed by a low-pass filter having a predetermined cutoff frequency.

According to the present embodiment, in a configuration in which one driven body is driven via a speed reducer by controlling a plurality of motors, the helix angle is calculated while the backlash generated by the speed reducer is suppressed, and torque calculation is performed. Since it can be performed, it is possible to detect a minute torque change with higher accuracy. In addition, the backlash generated by the speed reducer can be physically suppressed. This leads to suppressing the dead zone in control due to backlash, and can realize highly accurate control such as minute torque control.

[Second Embodiment]
Next, a second embodiment of the present invention will be described. Regarding the application of the motor control device, for example, in an electrically driven pan head equipped with a commercial camera, the quality of captured images may be affected by disturbances such as wind when used outdoors. In order to suppress the influence of disturbance such as wind with good responsiveness, it is required to measure the disturbance torque applied to the driven unit 30 and suppress the influence of the disturbance torque. In the present embodiment, a configuration example in which a motor control system is mounted in a drive unit that controls turning in the panning direction and the tilting direction of the electric drive platform is shown. In the present embodiment, the components having the same functions as those in the first embodiment are given the symbols already used, and detailed description thereof will be omitted. The method of omitting such a description is the same in the embodiments described later.

FIG. 5 is a control block diagram showing the configuration of the motor control system 1000 of the present embodiment. The difference from the first embodiment is that an external torque control unit 500 is added in order to suppress the influence of the disturbance torque.

The external torque control unit 500 acquires a torque estimated value (denoted as _TLest ) and a driven unit torque TL. The torque estimated value _TLest is an estimated value of the torque generated by driving the driven unit 30 generated by the track generation unit 210. The driven unit torque TL is the torque generated in the driven unit 30. The external torque control unit 500 estimates the disturbance torque (denoted as TL _dis ) included in the driven unit torque TL from the torque estimated value TL _est and the driven unit torque TL. The external torque control unit 500 calculates a disturbance suppression command value (denoted as TL _cor ), which is a command value for suppressing the disturbance torque TL _dis . The disturbance suppression command value TL _cor is acquired by performing an operation such as PID control on the disturbance torque TL _dis . The disturbance suppression command value TL _cor is input from the external torque control unit 500 to the control command setting unit 240.

The control command setting unit 240 acquires the disturbance suppression command value TL _cor , adds it to the backlash suppression command value C _BL , and outputs it to the drive device 100. That is, the disturbance suppression command value TL _cor includes a correction value for the suppression command value C _BL . In the orbit generation unit 210, it is necessary to set the load information of the image pickup device or the like attached to the driven unit 30 as a setting necessary for estimating the torque estimated value _TLest , and it is necessary to set the load information in the setting unit (not shown). And the setting process is executed.

In the motor control system 1000, by detecting the disturbance torque TL _dis such as wind applied to the driven unit 30 and performing the motor control, it is possible to control the disturbance torque TL _dis . In addition, it is possible to measure and control the disturbance torque while suppressing the backlash generated by the reducer. Especially in a situation where the wind direction is frequently switched, the electrically driven pan head can be controlled with higher accuracy, so that deterioration of the quality of the captured image can be suppressed.

[Third Embodiment]
A third embodiment of the present invention will be described with reference to FIG. When an industrial robot or the like is used to assemble products to each other or to apply a solvent to a product, the robot is required to control a minute torque. As the robot control system of the present embodiment, an example in which a motor control system is mounted on a drive unit of each joint axis of a 6-axis articulated robot which is a working device is shown.

FIG. 6 is a control block diagram showing the motor control system 2000 of the present embodiment. The torque control command unit 600 calculates a torque command value (denoted as _Tref ) in each joint axis for realizing a separately set desired operation. The torque command value _Tref is decomposed as a torque command value for each joint shaft and transmitted to the drive unit of each joint shaft. For example, the torque command value transmitted to the first axis of the 6-axis articulated robot is referred to as _Tref1 . Since the 6-axis articulated robot has the same control block configuration for each joint axis in the present embodiment, the first-axis control block configuration of the 6-axis articulated robot will be described below.

The controller 200 has a torque control unit 610 and a backlash suppression command calculation unit 230. The controller 200 controls the driven unit 30 so that it can operate at a desired torque based on the command value of the torque control command unit 600.

The torque control unit 610 acquires a deviation (denoted as T _df1 ) between the torque command value _Tref1 of the _first axis in the drive axis of the 6-axis articulated robot and the torque TL1 of the driven unit. The subtraction unit DEC4 calculates the torque deviation T _df1 . The torque control unit 610 performs feedback control so that the torque deviation T _df1 is suppressed, and outputs the torque control value (denoted as C _FBT 1) of the first axis. The feedback control is a general PID control, and an operation that combines proportionality, integration, and differentiation with respect to the deviation is performed.

The backlash suppression command calculation unit 230 generates a backlash suppression command value (denoted as C _BL 1) in order to cause a predetermined difference between the control command value of the first motor and the control command value of the second motor. do. The suppression command value C _BL1 is a fixed value or a variable value depending on the torque command value _Tref1 , and is input to the control command setting unit 240.

The control command setting unit 240 acquires the torque control value C _FBT1 and the backlash suppression command value C _BL1 . The control command setting unit 240 sets the torque control value C _FBT 1 as the driver command value V _PWM1 to the first motor unit 10 or the driver command to the second motor unit 20 according to the code of the torque control value C _FBT1 . Value V Determines whether to use _PWM2 . For example, in the case of driving in the positive torque direction, the torque control value C _FBT1 is set as the driver command value V _PWM1 to the first motor unit 10, and the backlash suppression command value C _BL1 is set as the driver command value to the second motor unit 20. Drive control is performed as V _PWM2 . In the case of driving in the negative torque direction, the backlash suppression command value C _BL1 is set as the driver command value V _PWM1 for the first motor unit 10, and the torque control value C _FBT1 is set as the driver command value for the second motor unit 20. Drive control is performed as V _PWM2 . This makes it possible to perform torque control while stably suppressing backlash generated in the speed reducer when switching the drive direction.

Since the motor control system 2000 can detect a minute load torque applied to the driven portion 30 on each drive shaft (joint shaft) of the working device (6-axis articulated robot), it is more accurate. Torque control is possible. Since high-precision torque control is possible in situations where minute torque control is required, it is possible to realize work such as assembling products with each other and applying a solvent to products.

In the present embodiment, the control of backlash suppression is executed during the execution of torque measurement, but it is not always necessary to set the control of backlash suppression to be an effective setting. For example, if the direction of the load torque does not change, the suppression command value C _BL is set to zero. By performing drive control while maintaining the same torque detection accuracy and controllability, it is possible to reduce the amount of heat generated by the drive device 100. Further, when the backlash amount is smaller than a predetermined threshold value, the suppression command value C _BL is set to zero, so that the same effect as described above can be exhibited.

According to the above embodiment, it is possible to provide a motor control device and a control method capable of more accurate torque control while suppressing a decrease in torque measurement accuracy due to the backlash of the speed reducer. Although the preferred embodiment of the present invention has been described, the present invention is not limited to the above-described embodiment, and various combinations, modifications and modifications can be made within the scope of the gist thereof.

10 First motor unit 20 Second motor unit 30 Driven unit 100 Drive device 200 Controller 221 First motor control unit 222 Second motor control unit 230 Backlash suppression command calculation unit 400 Load torque calculation unit

Claims (14)

It is a motor control device that controls the drive of the driven unit by a plurality of motors via a reducer.
The first control means for controlling the drive of the first motor using the first command value,
A second control means for controlling the drive of the second motor using a second command value different from the first command value, and
By acquiring the information on the position of the first motor, the information on the position of the second motor, and the information on the position of the driven portion, the torsion angle generated in the speed reducer is calculated, and the torsion angle and the said A motor control device including a calculation means for calculating the torque generated in the speed reducer from the rigidity value of the speed reducer. A first detecting means for detecting the driving position of the first motor, a second detecting means for detecting the driving position of the second motor, and a third detecting the position of the driven portion. The motor control device according to claim 1, further comprising a detection means. A storage means for storing torque data generated inside the speed reducer when driving the driven unit according to the first and second command values is provided.
The first or second aspect of the present invention is characterized in that the calculation means calculates the torque generated in the driven unit from the torque generated in the speed reducer and the data stored in the storage means. The motor control device described. The motor control according to any one of claims 1 to 3, further comprising a third control means for calculating a torque applied to the driven unit from the outside and controlling the torque. Device. The motor according to any one of claims 1 to 4, further comprising an acquisition means for acquiring a suppression command value that causes a difference between the first command value and the second command value. Control device. A third control means that calculates the torque applied to the driven unit from the outside and controls the suppression of the torque.
It is provided with an acquisition means for acquiring a suppression command value that causes a difference between the first command value and the second command value.
The third control means according to any one of claims 1 to 3, wherein the third control means controls torque applied to the driven portion by changing the suppression command value acquired by the acquisition means. The motor control device described. 3. The motor control device described. The motor control device according to any one of claims 1 to 7, wherein when the drive direction of the driven unit is switched, the calculation means changes the calculation method of the helix angle depending on the drive direction. .. The first or second control means is characterized in that when the drive direction of the driven unit is switched, the drive control of the first or second motor is used to control the decrease in torque measurement accuracy. The motor control device according to any one of claims 1 to 8. When the backlash amount generated by the speed reducer is larger than the threshold value, the first or second control means controls the drive control of the first or second motor to suppress a decrease in torque measurement accuracy. The motor control device according to any one of claims 1 to 9. 5. 6. The motor control device according to 6. An image pickup apparatus according to any one of claims 1 to 11, wherein the image pickup direction is changed by the motor control device. A control system characterized in that the drive control of the drive shaft of the work device is performed by the motor control device according to any one of claims 1 to 11. It is a motor control method executed by a motor control device that controls the drive of a driven unit by a plurality of motors via a reducer.
The first control process that controls the drive of the first motor using the first command value, and
A second control step of controlling the drive of the second motor using a second command value different from the first command value, and
By acquiring the information on the position of the first motor, the information on the position of the second motor, and the information on the position of the driven portion, the torsion angle generated in the speed reducer is calculated, and the torsion angle and the said A motor control method comprising a calculation process for calculating the torque generated in the speed reducer from the rigidity value of the speed reducer.

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