PH12016000059A1 - Motor control apparatus - Google Patents

Abstract

A motor control apparatus for cooperatively driving one movable portion with N pieces of motors, the motors being driven based on a common external position command, includes: a model control system configured to feed back a state to restrain an influence of vibrations to the movable portion, the model control system being configured to generate a model command based on the external position command; and N pieces of feedback control systems disposed corresponding to N pieces of the motors on a one-to-one basis, the feedback control systems being configured to perform a feedback control on the respective motors based on the model command. (N -1) pieces of the feedback control systems are configured to compensate a control error when controlling the respective motors with a difference between each of the control errors in the feedback control systems and a control error in the remaining one feedback control system.

Description

and a second feedback control system 70. ~

An external position command, which indicates a control position of a table 4 as = the movable portion, is input to the first model control system 10. The first model - control system 10 generates various first model commands. =

The first feedback control system 30 includes a feedback loop including the first motor 2. The first feedback control system 30 actually controls the first motor 2 based = on the first model command. _

The external position command identical to the command input to the first = model control system 10 is input to the second model control system 50. The second a model control system SO supplies various second model commands.

The second feedback control system 70 includes the feedback loop including the second motor 3. The second feedback control system 70 actually controls the second motor 3 based on the second model command.

In this embodiment, the first model command includes a first model position command, a first model speed command, and a first model torque command. The second model command includes a second model position command, a second model speed command, and a second model torque command.

The first feedback control system 30 includes a first control position error obtainer 31, a first synchronization position error obtainer 32, a first position synchronization compensator 33, a first synchronization compensation position error obtainer 34, a first position controller 35, a first detection speed obtainer 36, a first control speed error obtainer 37, a first speed controller 38, a first control torque obtainer 39, a first torque command low-pass filter 40, and a first torque controller 41. The first control position error obtainer 31, the first synchronization compensation position error obtainer 34, the first position controller 35, the first control speed error obtainer 37, the first speed controller 38, the first control torque obtainer 39, the first torque command low-pass filter 40, the first torque controller 41, the first motor 2, and a first sensor 42 are ~ included in a feedback loop that actually controls the first motor 2. =

The first motor 2 is, for example, a synchronous motor. The first sensor 42 © detects the rotation position of the first motor 2. The first sensor 42 is, for example, a - rotary encoder mounted to a rotor shaft of the first motor 2. The rotary encoder outputs n a pulse signal corresponding to the position of the rotor shaft of the motor. The pulse - signals are convertible to the rotation position of the first motor 2. -

The first control position error obtainer 31 obtains (generates) a first control @ position error based on the first model position command, which is supplied from the - first model control system 10, and a first detection position of the first motor 2, which is obtained from the first sensor 42. The first control position error indicates an error between these positions. The first control position error, for example, may be obtained by subtracting the first detection position from the first model position command.

The first synchronization position error obtainer 32 obtains a first synchronization position error based on the first control position error, which is obtained by the first control position error obtainer 31, and a second control position error, which is obtained by a second control position error obtainer 71 as described later. The first synchronization position error indicates a difference (a synchronization error) between these control position errors. The first synchronization position error, for example, may be obtained by subtracting another second control position error from the first control position error, which is obtained by the first control position error obtainer 31. In this case, the synchronization error of the first feedback control system 30 with respect to the second feedback control system 70 is obtained.

The first position synchronization compensator 33 obtains a first position synchronization error compensation amount based on the first synchronization position error. In this embodiment, for the first position synchronization compensator 33, for example, a proportional controller or a proportional-integral controller may be used. -

The first synchronization compensation position error obtainer 34 obtains the = first control position error after performing a synchronous compensation process based - on the first control position error, which is the control position error in the first feedback > control system 30, and the first position synchronization error compensation amount, which is a synchronous position error between the two feedback control systems. The o first control position error after performing the synchronous compensation process, for _ example, may be an addition value (a summed value) of the first control position error = and the first position synchronization error compensation amount.

The first position controller 35 obtains a first control speed based on the first control position error after performing the synchronous compensation process. The first position controller 35 obtains the first control speed according to the control position error in the first feedback control system 30 and the synchronous position error in the first feedback control system 30 using the second feedback control system 70 as a criterion. If the control position of the first feedback control system 30 delays with respect to the control position of the second feedback control system 70, the first control speed increases.

The first detection speed obtainer 36 obtains the first detection speed of the first motor 2 based on the rotation position detected by the first sensor 42. The first control speed error obtainer 37 obtains a first control speed error based on the first control speed, the first detection speed, and the first model speed command. The first control speed error, for example, may be a value found by adding the first model speed command to a control speed error obtained by subtracting the first detection speed from the first control speed. The first speed controller 38 obtains a first control torque based on the first control speed error. The first speed controller 38 obtains the first control torque according to the control speed error in the first feedback control system 30 and the first model speed command. An increase in at least one of the control speed error and the - first model speed command increases the first control torque. =

The first control torque obtainer 39 obtains a first total control torque based on = the first control torque and the first model torque command. The first total control > torque may be, for example, a value found by adding the first control torque and the first - model torque command. The first torque command low-pass filter 40 performs a low- = pass filter process on the first total control torque. Through this low-pass filter process, _ high-frequency components can be removed from the first total control torque. Such 5 high-frequency components include, for example, quantized ripple components of the 3 position by the first sensor 42. The first torque controller 41 controls the first motor 2 based on the first total control torque after performing the low-pass filter process.

Thus, by the feedback control by the first feedback control system 30, the first feedback control system 30 rotatably drives the first motor 2 according to the first model position command, the first model speed command, and the first model torque command, which are output from the first model control system 10. In accordance with the rotation of the first motor 2, the table 4 is driven. If an error occurs in the control position or the control speed in the first feedback control system 30 or if the control position of the first feedback control system 30 is shifted with respect to the control position of the second feedback control system 70, the driving torque of the first motor 2 increases or decreases so as to restrain these error and deviation. Accordingly, the first motor 2 moves to follow the first model torque command and the first model speed command, and is controlled up to the position according to the first model position command.

The first model control system 10 inputs the external position command and operates a virtual behavior of the first feedback control system 30 using the model corresponding to the first feedback control system 30. Thus, the first model control system 10 generates the first model command provided to the first feedback control ~ system 30. =

The first model position command is a command indicative of the control ~ position of the first motor 2. The first model speed command is a command indicative - ofthe control speed of the first motor 2 during driving. The first model torque - command is a command indicative of the control torque of the first motor 2 during - driving. ~

To operate behaviors of the first feedback control system 30, the first model @ control system 10 of this embodiment includes a first model position error operator 11, a y first model position controller 12, a first model speed operator 13, a first model speed error operator 14, a first model speed controller 15, a first model torque error operator 16, a first model torque command low-pass filter 17, a first movable portion model 18, a first machine table model 19, a first model position adder 20, and a first state feedback amount operator 21.

The first state feedback amount operator 21 includes a first machine table feedback amount operator 22, a first filter feedback amount operator 23, and a first total feedback amount operator 24. Accordingly, if the table 4 vibrates on the machine table due to vibrations of the machine table, the first state feedback amount operator 21 operates a total feedback amount to restrain an influence of vibrations of the machine table to the table 4.

The first model position error operator 11, the first model position controller 12, the first model speed error operator 14, the first model speed controller 15, the first model torque error operator 16, the first model torque command low-pass filter 17, the first movable portion model 18, the first machine table model 19, and the first model position adder 20 are included in a main feedback loop in the first model control system 10. This main feedback loop of the first model control system 10 corresponds to the feedback loop of the first feedback control system 30. =

The first model position error operator 11 operates a first model position error - based on the model corresponding to the first control position error obtainer 31. The " first model position error operator 11 subtracts a first model position, which is output - from the first model position adder 20, from the external position command to operate = the first model position error. -

The first model position controller 12 operates a first model speed based on the - : model corresponding to the first position controller 35. The first model position © controller 12 operates the first model speed based on the first model position error. i.

The first model speed operator 13 operates a first model detection speed based on the model corresponding to the first detection speed obtainer 36. The first model speed operator 13 operates the first model detection speed based on the first model position. The first model detection speed is output to the first feedback control system 30 as the first model speed command.

The first model speed error operator 14 operates a first model speed error based on the model corresponding to the first control speed error obtainer 37. The first model speed error operator 14 subtracts the first model detection speed from the first model speed to operate the first model speed error.

The first model speed controller 15 operates a first model torque based on the model corresponding to the first speed controller 38. The first model speed controller 15 operates the first model torque based on the first model speed error.

The first model torque error operator 16 subtracts the total feedback amount, which is operated by the first state feedback amount operator 21, from the first model torque to operate a first model torque after performing state feedback compensation.

The first model torque after performing the state feedback compensation is output to the first feedback control system 30 as the first model torque command. 12 -.______________________________

The first model torque command low-pass filter 17 performs a filter operation based on the model corresponding to the first torque command low-pass filter 40. The ® first model torque command low-pass filter 17 performs the low-pass filter process on = the first model torque after performing the state feedback compensation. =

The first movable portion model 18 operates the position of the movable portion model based on the model of the movable portion corresponding to the motion of the o mechanical system from the first motor 2 to the table 4. Here, as the movable portion _ model corresponding to the mechanical system including the first motor 2 and from a = first ball screw 5 to the table 4, a rigid body model where a deviation is less likely to © occur among them is used. The first movable portion model 18 operates the position of the first movable portion model 18 based on the first model torque after performing the state feedback compensation process and the low-pass filter process.

The first machine table model 19 operates the position of a machine table model based on the model of the machine table corresponding to the motion of the machine table to which the first motor 2 and the table 4 are mounted. The machine table is, for example, placed on a floor with leveling bolts. When the table 4 is moved at high speed, the machine table may vibrate. In this case, the relative position of the table 4 to the machine table may be shifted from the position when the machine table does not vibrate.

The model of the machine table may be, for example, obtained by modeling the vibrations of this machine table. The first machine table model 19 operates the position of the first machine table model 19 based on the first model torque after performing the state feedback compensation process and the low-pass filter process.

The first model position adder 20 adds the position of the first movable portion model 18 and the position of the first machine table model 19 to operate the first model position. The first model position, which is operated by the first model position adder 20, is output to the first feedback control system 30 as a first model position command. 13 a —

The first machine table feedback amount operator 22 operates a feedback - amount of the vibrating position (a first machine table feedback amount). Specifically, = for example, the first machine table feedback amount is operated as follows: the first . machine table feedback amount operator 22 multiplies the position of the first machine ~ table model 19 by an addition gain (Kp + KvgS + KasS?), which is an addition of a - machine table position feedback gain Kpg, a machine table speed feedback gain KvsS, - and a machine table acceleration feedback gain KAgS>. Here, S indicates a differential - operator. @

The first filter feedback amount operator 23 operates the feedback amount of the o filter process of the first model torque command low-pass filter 17. Specifically, for example, the filter process feedback amount is operated as follows: the first filter feedback amount operator 23 multiplies the first model torque after performing the state feedback compensation process and the low-pass filter process by a filter process feedback gain Kp.

The first total feedback amount operator 24 adds various feedback amounts operated by the first state feedback amount operator 21. Here, the first total feedback amount operator 24 operates a total feedback amount by adding the first machine table feedback amount and the filter process feedback amount. The operated total feedback amount is output to the first model torque error operator 16.

By the feedback control corresponding to the first feedback control system 30, the first model control system 10 generates a first model position command, a first model speed command, and a first model torque command, which can restrain vibrations between the machine table and the table 4.

To the respective elements of the first model control system 10, control parameters may be set such that the control to the table 4 may be a desired positioning control. For example, the parameters are calculated and set such that a characteristic 14

J TR RR RRR EE ————————

equation with respect to an equation of state of the first model control system 10 has a " fivefold root. ©

Setting the parameters having the fivefold root allows the first model control = system 10 to generate the model command with which vibrations between the table 4 and > the machine table are less likely to occur. By driving the first feedback control system 30 by the model command with which vibrations are less likely to occur between the © table 4 and the machine table from the first model control system 10, the table 4 actually . driven by the first feedback control system 30 is also less likely to generate vibrations. = rs

Enhancing gains of the first model control system 10 and the first feedback ~ control system 30 in a range of allowable stability in the first feedback control system 30 ensures high-speed driving of the table 4 while actually restraining vibrations between the table 4 and the machine table.

The second feedback control system 70 includes the second control position error obtainer 71, a second position controller 75, a second detection speed obtainer 76, a second control speed error obtainer 77, a second speed controller 78, a second control torque obtainer 79, a second torque command low-pass filter 80, and a second torque controller 81. The second control position error obtainer 71, the second position controller 75, the second control speed error obtainer 77, the second speed controller 78, the second control torque obtainer 79, the second torque command low-pass filter 80, the second torque controller 81, the second motor 3, and a second sensor 82 are included in a feedback loop that actually controls the second motor 3.

These respective components of the second feedback control system 70 designate identical components to the first feedback control system 30 with different numbers (reference numerals) but the approximately identical names, and therefore such elements are not further explained here. Note that the second position controller 75 obtains a second control speed based on the second control position error obtained by the 15 ee ——

second control position error obtainer 71. That is, unlike the first feedback control ° system 30, the second feedback control system 70 obtains the second control speed based on the second control position error on which the synchronous compensation process is o not performed. -

To operate behaviors of the second feedback control system 70, the second = model control system 50 includes a second model position error operator 51, a second - model position controller 52, a second model speed operator 53, a second model speed - error operator 54, a second model speed controller 55, a second model torque error © operator 56, a second model torque command low-pass filter 57, a second movable o portion model 58, a second machine table model 59, a second model position adder 60, and a second state feedback amount operator 61.

The second state feedback amount operator 61 includes a second machine table feedback amount operator 62, a second filter feedback amount operator 63, and a second total feedback amount operator 64. Thus, the second state feedback amount operator 61 operates the total feedback amount, which is to restrain vibrations of the table 4 to the machine table when the table 4 vibrates on the machine table caused by vibrations of the machine table.

The second model position error operator 51, the second model position controller 52, the second model speed error operator 54, the second model speed controller 55, the second model torque error operator 56, the second model torque command low-pass filter 57, the second movable portion model 58, the second machine table model 59, and the second model position adder 60 are included in the main feedback loop of the second model control system 50. This main feedback loop of the second model control system 50 corresponds to the feedback loop of the second feedback i control system 70.

These respective components of the second model control system 50 designate fo identical components to the first model control system 10 with different numbers o (reference numerals) but the approximately identical names, and therefore such elements = ho are not further explained here. To parameters of the respective units of the second = model control system 50, values identical to the first model control system 10 are set. 7 i

As various signal names for the second feedback control system 70 and the be second model control system 50, the following description uses corresponding various = ; signal names for the first feedback control system 30 and the first model control system = whose numbers are changed from "first" to "second." =

The above-described various signals include, for example, the first model - 10 command, the first model position command, the first model speed command, and the first model torque command. Additionally, the above-described various signals include, for example, signals corresponding to the respective first detection position, first control position error, first synchronization position error, first position synchronization error compensation amount, first control position error after performing the synchronous compensation process, first control speed, first detection speed, first control speed error, first control torque, first total control torque, first total control torque on which the low- pass filter process has been performed, first model position error, first model speed, first model detection speed, first model speed error, first model torque, first model torque after performing the state feedback compensation, first model torque on which the state feedback compensation process and the low-pass filter process have been performed, first model position, and first machine table feedback amount.

Thus, the parameters with identical values are used between a control system with axis 1 and a control system with axis 2. This simultaneously outputs commands from the first model control system 10 and the second model control system 50 at the identical value to the respective axes. This results in concurrent application of torques to the respective axes. 17 __ a

In the motor control apparatus 1 illustrated in Fig. 1, the first sensor 42 may be integrated with the first motor 2. The components of the first feedback control system = 30 other than the first motor 2 and the first sensor 42 and the first model control system o 10 may be provided as a first computer device in a first motor control apparatus, which is ik connected to the first motor 2 and the first sensor 42 with a first cable. In this case, the - components of the first feedback control system 30 perform respective processes by = arithmetic operations (that is, for example, the first computer device performs these = arithmetic operations). These arithmetic operations can preferably correspond to = arithmetic operations of the respective units of the first model control system 10. =

Similarly, the second sensor 82 may be integrated with the second motor 3.

The components of the second feedback control system 70 other than the second motor 3 and the second sensor 82 and the second model control system SO may be provided as a second computer device in a second motor control apparatus, which is connected to the second motor 3 and the second sensor 82 with a second cable. In this case, the components of the second feedback control system 70 perform respective processes by arithmetic operations (that is, for example, the second computer device performs these arithmetic operations). These arithmetic operations can preferably correspond to arithmetic operations of the respective units of the second model control system 50.

In the case of using the first motor control apparatus and the second motor control apparatus in this manner, the first motor control apparatus is coupled to the second motor control apparatus with, for example, a communication cable. The second motor control apparatus transmits the second control position error to the first motor control apparatus.

Besides, for example, the first computer device and the second computer device may be disposed in single motor control apparatus. The components in Fig. 1 other than the first motor 2, the first sensor 42, the second motor 3, and the second sensor 82 poi may be provided as the single computer device in single motor control apparatus. In i this case, the second control position error is transmittable by, for example, program-to- - program communications. =

The first model control system 10 and the second model control system 50 may . be included in one model control system. From this single model control system, a i common model command may be supplied to the first feedback control system 30 and the second feedback control system 70. =

Next, the following describes behaviors by the motor control apparatus 1 in Fig. > . os

To control the position of the table 4, an upper controller simultaneously supplies a common external position command to the first model control system 10 and the second model control system 50.

The first model control system 10 to which the external position command has been supplied subtracts the first model position from the external position command to operate the first model position error. Further, the first model control system 10 operates the first model speed based on the first model position error. Additionally, the first model control system 10 operates the first model detection speed based on the first model position. The first model control system 10 subtracts the first model detection speed from the first model speed to operate the first model speed error. The first model control system 10 operates the first model torque based on the first model speed error.

The first model control system 10 subtracts the total feedback amount from the first model torque to operate the first model torque after performing the state feedback compensation. The first model control system 10 performs the low-pass filter process on the first model torque after performing the state feedback compensation.

The first model control system 10 operates the position of the first movable portion model 18 and the position of the first machine table model 19 based on the first model torque after performing the state feedback compensation process and the low-pass = filter process, and adds these values to operate the first model position. =

The first model control system 10 operates the feedback amount of the vibrating o position and the feedback amount of the filter process, and adds these values to operate a the total feedback amount. By this sequence of arithmetic operations, the first model - control system 10 generates the first model position command, the first model speed = command, and the first model torque command as the first model commands and outputs oo the commands to the first feedback control system 30. c

The first feedback control system 30 to which the first model command has or been supplied obtains the first control position error. The first control position error indicates a position error between the first model position command and the first detection position that is obtained from the first sensor 42. The first feedback control system 30 obtains the first synchronization position error. The first synchronization position error indicates a difference (a difference in position error, a synchronization error) between the first control position error of itself and the second control position error that is obtained by the second control position error obtainer 71. Further, the first feedback control system 30 obtains a first position synchronization error compensation amount based on the first synchronization position error.

The first feedback control system 30 obtains the first control position error after performing the synchronous compensation process based on the first control position error and the first position synchronization error compensation amount. Further, the first feedback control system 30 obtains the first control speed based on the first control position error after performing the synchronous compensation process.

The first feedback control system 30 obtains the first control speed error based on the first control speed, the first detection speed, and the first model speed command.

The first feedback control system 30 obtains the first control torque based on the first control speed error. ~

The first feedback control system 30 obtains the first total control torque based - on the first control torque and the first model torque command. The first feedback © control system 30 performs the low-pass filter process on the first total control torque. -

The first torque controller 41 of the first feedback control system 30 controls the nN first motor 2 based on the first total control torque after performing the low-pass filter - process. The first sensor 42 detects the rotation position of the first motor 2. The first . detection speed obtainer 36 obtains the first detection speed based on the rotation © position detected by the first sensor 42.

Simultaneous with the supply of the external position command to the first model control system 10, the identical external position command is supplied to the second model control system 50. The second model control system 50 performs the above-described feedback control identical to the first model control system 10.

The second feedback control system 70 to which the second model command is supplied from the second model control system 50 also performs the above-described feedback control identical to the first feedback control system 30. Note that the second feedback control system 70 does not include components corresponding to the first synchronization position error obtainer 32, the first position synchronization compensator 33, and the first synchronization compensation position error obtainer 34 of the first feedback control system 30. The second position controller 75 obtains the second control speed from the second control position error obtained by the second control position error obtainer 71. That is, the second position controller 75 obtains the second control speed based on the second control position error on which the synchronous compensation process is not performed.

In the embodiment, two feedback control systems each perform the feedback control on the motors not by the external position command but by the model command.

Moreover, two model control systems, which generate the model command from the - external position command, include the movable portion model, which corresponds to = fod the motion of the movable portion driven with the two motors, and the machine table = model, which corresponds to the motion of the machine table to which the motors and the movable portion are mounted. The two model control systems feed back the state Ae of the machine table model to restrain vibrations between the machine table and the table = 4 caused by vibrations of the machine table. Accordingly, the two model control © systems restrain the relative vibrations of the machine table to the table 4, and stabilize = the machine table and/or the table 4. “

Accordingly, the two feedback control systems perform the stable feedback control independent of each other to follow the models such that the relative vibrations of the machine table to the table 4 is less likely to occur. This allows the two motors to be controlled so as to similarly follow the external position command.

The two feedback control systems can control the two motors by the common external position command simultaneously input so as to synchronize the two motors with one another. Even if the machine table to which the table 4 is mounted vibrates, the two feedback control systems can restrain vibrations of the table 4 and synchronize the two motors with one another.

Moreover, in this embodiment, the first feedback control system 30 compensates the control error of itself with the difference between the control error of itself (for example, the control position error) and the control error in the second feedback control system 70 (for example, the control position error). While the first feedback control system 30 synchronizes the two motors with one another such that a deviation of control error of itself with respect to the control error in the second feedback control system 70 is less likely to occur, the first feedback control system 30 performs the feedback control on itself. In other words, while the feedback control systems, which are independent of

Fu each other, control the two motors so as to be independent of each other, the deviation in - control error possibly occurring between the first feedback control system 30 and the = second feedback control system 70 can be compensated. That is, the two feedback = control systems can compensate the deviation in the control error possibly occurring vr between these two feedback control systems. =

Thus, in this embodiment, a model following control on the two motors that = cooperatively move one movable portion is performed by the common external position © command and using the identical model to feed back the state so as to restrain the = vibrations between the machine table and the table 4. This allows making the torque “ commands provided to the two feedback control systems to be identical between all axes.

Even if the machine table possibly vibrates, the vibrations between the machine table and the table 4 can be restrained. Therefore, the control such that the deviation is less likely to occur between the control errors in the two feedback control systems can be performed.

Due to another cause, a slight deviation between control errors may occur between the two feedback control systems. In this embodiment, this deviation is compensated between the two feedback control systems. Accordingly, the control . systems with two motors perform controls where a control less likely to generate a synchronization deviation caused by vibrations and a control for restraining the synchronization deviation are duplicated. This ensures enhancing the synchronization accuracy of two motors to control one movable portion with the two motors.

Consequently, in this embodiment, even if the machine table vibrations possibly occur in the machine that drives one movable portion with two motors, the vibrations between this machine table and the table 4 can be restrained. This ensures enhancing the following capability of the two motors to commands. Further, the synchronization accuracy between the two motors can be ensured, and as a result, the high-speed and high-accuracy positioning can be performed. ©

In the example described in the embodiment, two sets of model control systems o and feedback control systems are used to drive the movable portion with two motors. -

In the example, a synchronization position error obtainer, a position synchronization - compensator, and a synchronization compensation position error obtainer are applied to the first feedback control system. Besides, the synchronization position error obtainer, - the position synchronization compensator, and the synchronization compensation - position error obtainer may be applicable to the second feedback control system. =

Furthermore, the movable portion may be driven with three or more motors. In this case, the model control systems and feedback control systems may be disposed basically by the identical number of sets to the motors.

N (N is a natural number of two or more) pieces of motors may drive the movable portion. In this case, the synchronization position error obtainers, the position synchronization compensators, and the synchronization compensation position error obtainers may be disposed in (N — 1) pieces of feedback control systems. It is only necessary for (N — 1) pieces of the synchronization position error obtainers in (N — 1) pieces of the feedback control systems to, for example, obtain a synchronization position error based on these respective control position errors and the control position error of the remaining one feedback control system.

If the table 4 vibrates on the machine table due to vibrations of the machine table, the first state feedback amount operator 21 may operate a total feedback amount to restrain vibrations of the table 4 to the machine table.

Various signal names for the second feedback control system 70 and the second model control system 50 may employ corresponding various signal names for the first feedback control system 30 and the first model control system 10 whose numbers are changed from the first to the second. The use of the parameters with identical values 24

LL between the control system with axis 1 and the control system with axis 2 may = simultaneously output commands from the first model control system 10 and the second = model control system 50 at the identical value to the respective axes. This results in ~ concurrent application of torques to the axes. ~

Second Embodiment =

Fig. 2 is a block diagram of the motor control apparatus 1 according to a second : embodiment of the present invention. The motor control apparatus 1 illustrated in Fig. = 2 differs from the motor control apparatus 1 illustrated in Fig. 1 in that the second @ feedback control system 70 includes a second synchronization position error obtainer 72, = a second position synchronization compensator 73, and a second synchronization compensation position error obtainer 74.

The second synchronization position error obtainer 72, the second position synchronization compensator 73, and the second synchronization compensation position error obtainer 74 correspond to the first synchronization position error obtainer 32, the first position synchronization compensator 33, and the first synchronization compensation position error obtainer 34.

The second synchronization position error obtainer 72 obtains a second synchronization position error based on the second control position error, which is obtained by the second control position error obtainer 71, and the first control position error, with is obtained by the first control position error obtainer 31. The second synchronization position error indicates a difference (a synchronization error) between these control position errors. The second synchronization position error, for example, may be operated by subtracting another first control position error from the second control position error that is obtained by the second control position error obtainer 71.

In this case, the synchronization error of the second feedback control system 70 with respect to the first feedback control system 30 is obtained.

The second position synchronization compensator 73 obtains a second position - synchronization error compensation amount based on the second synchronization = position error. In this embodiment, a deviation in control position errors between the no first feedback control system 30 and the second feedback control system 70 is mutually on compensated. Therefore, the proportional controller may be used for the first position synchronization compensator 33 and the second position synchronization compensator - 2 .

The second synchronization compensation position error obtainer 74 obtains the = second control position error after performing the synchronous compensation process ~ based on the second control position error, which is the control position error in the second feedback control system 70, and the second position synchronization error compensation amount, which is a synchronous position error between the two feedback control systems. The second control position error after performing the synchronous compensation process, for example, may be an addition value (a summed value) of the second control position error and the second position synchronization error compensation amount.

The second position controller 75 obtains a second control speed based on the second control position error after performing the synchronous compensation process.

The second position controller 75 obtains the second control speed according to the control position error in the second feedback control system 70 and the synchronous position error in the second feedback control system 70 using the first feedback control system 30 as a criterion. If the control position of the second feedback control system 70 delays with respect to the control position of the first feedback control system 30, the second control speed increases.

The configurations and behaviors of the motor control apparatus 1 illustrated in

Fig. 2 other than these are similar to those illustrated in Fig. 1, and therefore the description thereof is omitted here. -

In this embodiment, the first feedback control system 30 and the second © feedback control system 70 can mutually compensate the position error between two - axes (for example, a deviation in control position error). Consequently, even if the - control responses from the individual feedback control systems are not high, the position error between the axes can be decreased and the synchronization accuracy can be - increased. This embodiment can be expected to provide the synchronization accuracy . further higher than the first embodiment. =

In view of this, for example, by causing the first feedback control system 30 and o the second feedback control system 70 to follow the identical vibration model, the synchronization error is less likely to occur and the synchronization error between the axes caused by other causes can be efficiently restrained compared with the first embodiment.

Thus, in this embodiment, the individual model control systems are provided using the identical model in the machine that drives one movable portion with a plurality of (here, two) motors. Further, the actual feedback control systems perform control so as to follow this model. Accordingly, even if machine table vibrations possibly occur, vibrations between this machine table and the table 4 can be restrained. Thus, the synchronization accuracy between the two motors can be ensured, and consequently, the high-speed and high-accuracy positioning can be performed.

Third Embodiment

Fig. 3 is a block diagram of the motor control apparatus 1 according to the third embodiment of the present invention. The motor control apparatus 1 illustrated in Fig. 3 includes the first model control system 10, the first feedback control system 30, the second model control system 50, and the second feedback control system 70. Similar to the motor control apparatus 1 illustrated in Fig. 1, the motor control apparatus 1 illustrated in Fig. 3 cooperatively drives one movable portion using two motors, i.€., the = first motor 2 and the second motor 3. Accordingly, the motor control apparatus 1 = ensures high-speed, high-accuracy positioning of the movable portion.

The following mainly describes differences with the motor control apparatus 1 o illustrated in Fig. 1. Like reference numerals designate corresponding or identical a components throughout the motor control apparatuses 1 in Figs. 1 and 3, and therefore = such elements are not further explained here. -

The first feedback control system 30 includes the first control position error = obtainer 31, the first synchronization position error obtainer 32, the first position - synchronization compensator 33, the first synchronization compensation position error obtainer 34, the first position controller 35, the first detection speed obtainer 36, the first control speed error obtainer 37, the first speed controller 38, the first control torque obtainer 39, and the first torque controller 41.

The first control position error obtainer 31, the first synchronization compensation position error obtainer 34, the first position controller 35, the first control speed error obtainer 37, the first speed controller 38, the first control torque obtainer 39, the first torque controller 41, the first motor 2, and the first sensor 42 are included in a feedback loop that actually controls the first motor 2. The first torque controller 41 controls the first motor 2 based on the first total control torque output from the first control torque obtainer 39.

The first model control system 10 inputs the external position command, and operates a virtual behavior of the first feedback control system 30 using the model corresponding to the first feedback control system 30. The first model control system 10 generates the first model command provided to the first feedback control system 30.

To operate behaviors of the first feedback control system 30, the first model control system 10 of this embodiment includes the first model position error operator 11,

the first model position controller 12, a first front stage state compensation model speed © error operator 91, a first rear stage state compensation model speed error operator 92, the i. first model speed controller 15, a first front stage state compensation model torque error - operator 93, a first rear stage state compensation model torque error operator 94, a first o two-inertia model 95, a first torque feedback amount operator 106, and a first speed feedback amount operator 107. -

The first model position error operator 11, the first model position controller 12, - the first front stage state compensation model speed error operator 91, the first rear stage = state compensation model speed error operator 92, the first model speed controller 15, 5 the first front stage state compensation model torque error operator 93, the first rear stage state compensation model torque error operator 94, and the first two-inertia model 95 are included in the main feedback loop of the first model control system 10. This main feedback loop of the first model control system 10 corresponds to the feedback loop of the first feedback control system 30.

As the behavior of the mechanical system from the first motor 2 to the table 4, the first two-inertia model 95 operates the behavior of the vibrating table 4. The two- i inertia model is a model that expresses the mechanical system by two models, i.e., a motor side model corresponding to the first motor 2 side and a load side model corresponding to the table 4 side. The two-inertia model accommodates torsional vibration components between the motor side model and the load side model.

The first two-inertia model 95 of this embodiment includes a first motor side model 96, a first front stage motor side integrator 97, a first rear stage motor side integrator 98, a first torsional torque operator 99, a first load side model 100, a first front stage load side integrator 101, a first rear stage load side integrator 102, an inside-first- model acceleration error operator 103, an inside-first-model speed error operator 104, and an inside-first model position error operator 105.

The first motor side model 96 operates a first motor side model acceleration as ~ follows: the first motor side model 96 multiplies the first model torque after performing a = state compensation described later to be input to the first two-inertia model 95 by 1/JM gain accommodating a motor side inertia. =

The first front stage motor side integrator 97 integrates the first motor side n model acceleration to operate a first motor side model speed. The first motor side - model speed can be used as a model speed obtained by the first two-inertia model 95. -

The first motor side model speed is output as the first model speed command. =

The first rear stage motor side integrator 98 integrates the first motor side model > speed to operate the first motor side model position. The first motor side model position can be used as a model position obtained by the first two-inertia model 95.

The first motor side model position is output as the first model position command.

The first load side model 100 multiplies a first torsional torque, which is operated by the first torsional torque operator 99, by 1/JL gain accommodating a load side inertia to operate a first load side model acceleration.

The first front stage load side integrator 101 integrates the first load side model acceleration to operate a first load side model speed. The first rear stage load side integrator 102 integrates the first load side model speed to operate the first load side model position. The inside-first-model acceleration error operator 103 subtracts the first load side model acceleration from the first motor side model acceleration to operate an inside-first-model acceleration error.

The inside-first-model speed error operator 104 subtracts the first load side model speed from the first motor side model speed to operate an inside-first-model speed error. The inside-first model position error operator 105 subtracts the first load side model position from the first motor side model position to operate an inside-first-model position error. The first torsional torque operator 99 multiplies the inside-first-model

Lo position error by a gain KB, which corresponds to torsional rigidity, to obtain the first ~ torsional torque. ©

The vibration model allows the two-inertia model to operate behaviors - generating torsional vibrations between the motor side model and the load side model.

The first torque feedback amount operator 106 and the first speed feedback amount operator 107 operate the feedback amount that is a feedback amount of the state = of the two-inertia model. The first torque feedback amount operator 106 multiplies the - inside-first-model acceleration error by feedback gain KAB to operate a first torque = feedback amount. The first speed feedback amount operator 107 multiplies the inside- 7 first-model speed error by feedback gain KVB to operate a first speed feedback amount.

The first front stage state compensation model speed error operator 91 subtracts the first speed feedback amount from the first model speed that is operated by the first model position controller 12. The first rear stage state compensation model speed error operator 92 subtracts the first motor side model speed from the arithmetic operation result of the first front stage state compensation model speed error operator 91. Thus, the state feedback amount related to the speed operated by the first two-inertia model 95 is subtracted from the error (the first model speed error) between the first model speed error and the first motor side model speed. Accordingly, the compensated first model speed error after performing the state compensation is obtained. The first model speed controller 15 operates the first model torque from the first model speed error after performing the state compensation.

The first front stage state compensation model torque error operator 93 subtracts the first torque feedback amount from the first model torque. The first rear stage state compensation model torque error operator 94 subtracts the first torsional torque from the arithmetic operation result of the first front stage state compensation model torque error operator 93. Thus, the state feedback amount related to the acceleration operated by the first two-inertia model 95 is subtracted from the error (the first model torque error) - between the first model torque and the first torsional torque. Accordingly, the = compensated first model torque error after performing the state compensation is obtained. 3

The first model torque error after performing this state compensation is output to the first or motor side model 96 of the first two-inertia model 95. The first model torque error after - performing the state compensation is a model torque provided to the first two-inertia = model 95, and is output as the first model torque command. =

The first model control system 10 generates the first model position command, © the first model speed command, and the first model torque command by the feedback ” control corresponding to the first feedback control system 30.

To the respective elements of the first model control system 10, control parameters to ensure a desired positioning control of the table 4 may be set. In this embodiment, a state feedback of an acceleration difference (an inside-model acceleration error) and a speed difference (the inside-model speed error) between the motor side model and the load side model is performed using a two-inertia system machine model.

In this case, by the application of the modern control theory, parameters where the table 4 is stabilized to be less likely to vibrate are calculated. By calculating and setting the parameters such that the characteristic equation with respect to the equation of state of the model control system has a fourfold root, the table 4 is stabilized so as to be less likely to vibrate.

The second feedback control system 70 includes the second control position error obtainer 71, the second position controller 75, the second detection speed obtainer 76, the second control speed error obtainer 77, the second speed controller 78, the second control torque obtainer 79, and the second torque controller 81. Then, the second control position error obtainer 71, the second position controller 75, the second detection speed obtainer 76, the second control speed error obtainer 77, the second speed controller

78, the second control torque obtainer 79, the second torque controller 81, the second ~ motor 3, and the second sensor 82 are included in the feedback loop that actually © controls the second motor 3. =

These respective components of the second feedback control system 70 on designate identical components to the first feedback control system 30 with different - numbers (reference numerals) but the approximately identical names, and therefore such ° elements are not further explained here. Note that the second position controller 75 _ obtains a second control speed based on the second control position error obtained by the > second control position error obtainer 71. That is, unlike the first feedback control © system 30, the second feedback control system 70 obtains the second control speed based on the second control position error on which the synchronous compensation process is not performed.

To operate behaviors of the second feedback control system 70, the second model control system 50 includes the second model position error operator 51, the second model position controller 52, a second front stage state compensation model speed error operator 111, a second rear stage state compensation model speed error operator 112, the second model speed controller 55, a second front stage state compensation model torque error operator 113, a second rear stage state compensation model torque error operator 114, a second two-inertia model 115, a second torque feedback amount operator 126, and a second speed feedback amount operator 127.

The second two-inertia model 115 includes a second motor side model 116, a second front stage motor side integrator 117, a second rear stage motor side integrator 118, a second torsional torque operator 119, a second load side model 120, a second front stage load side integrator 121, a second rear stage load side integrator 122, an inside- second-model acceleration error operator 123, an inside-second-model speed error operator 124, and an inside-second-model position error operator 125.

The second model position error operator 51, the second model position o controller 52, the second front stage state compensation model speed error operator 111, = the second rear stage state compensation model speed error operator 112, the second - model speed controller 55, the second front stage state compensation model torque error - operator 113, the second rear stage state compensation model torque error operator 114, wn and the second two-inertia model 115 are included in the main feedback loop of the - second model control system 50. This main feedback loop of the second model control - system 50 corresponds to the feedback loop of the second feedback control system 70. =

These respective components of the second model control system 50 designate = identical components to the first model control system 10 with different numbers (reference numerals) but the approximately identical names, and therefore such elements are not further explained here. To parameters of the respective units of the second model control system 50, values identical to the first model control system 10 are set.

As various signal names for the second feedback control system 70 and the second model control system 50, the following description uses corresponding various signal names for the first feedback control system 30 and the first model control system 10 whose numbers are changed from "first" to second."

The above-described various signals include, for example, the first model command, the first model position command, the first model speed command, and the first model torque command.

Additionally, the above-described various signals include signals corresponding to the respective first motor side model acceleration, first motor side model speed, first motor side model position, first load side model acceleration, first load side model position, inside-first-model acceleration error, inside-first-model speed error, first torsional torque, first torque feedback amount, and first model torque error.

Further, the above-described various signals include signals corresponding to the respective first detection position, first control position error, first synchronization position error, first position synchronization error compensation amount, first control ® position error after performing the synchronous compensation process, first control speed, = first detection speed, first control speed error, first control torque, first total control > torque, first total control torque on which the low-pass filter process has been performed, ~ first model position error, first model speed, first model detection speed, first model c speed error, first model torque, first model torque after performing the state feedback _ compensation, first model torque on which the state feedback compensation process and = the low-pass filter process have been performed, first model position, and first machine = table feedback amount.

Thus, the parameters with identical values are used between a control system with axis 1 and a control system with axis 2. This simultaneously outputs commands from the first model control system 10 and the second model control system 50 at the identical value to the respective axes. This results in concurrent application of torques to the respective axes.

Next, the following describes behaviors by the motor control apparatus 1 illustrated in Fig. 3.

To control the position of the table 4, the upper controller simultaneously supplies a common external position command to the first model control system 10 and the second model control system 50.

The first model control system 10 to which the external position command has been supplied subtracts the first model position from the external position command to operate the first model position error. Additionally, the first model control system 10 operates the first model speed based on the first model position error. The first model control system 10 subtracts the first speed feedback amount from the first model speed.

The first model control system 10 further subtracts the first motor side model speed from the arithmetic operation result to operate the first model speed error after performing the - state compensation. The first model control system 10 operates the first model torque = based on the first model speed error after performing the state compensation. The first . model control system 10 subtracts the first torque feedback amount and the first torsional = torque from the first model torque to operate the first model torque error after performing the state compensation. -

First, the first two-inertia model 95 operates the first motor side model - acceleration based on the first model torque error after performing the state = compensation and then operates the first motor side model speed and the first motor side o model position. The first two-inertia model 95 operates the first load side model acceleration based on the first torsional torque and then operates the first load side model speed and the first load side model position. The first two-inertia model 95 operates the inside-first-model acceleration error, the inside-first-model speed error, and the inside- first-model position error, which are differences between the motor side and the load side.

The first two-inertia model 95 operates the first torsional torque, the first torque feedback amount, and the first speed feedback amount.

By this sequence of arithmetic operations, the first model control system 10 generates the first model position command, the first model speed command, and the first model torque command as the first model commands and outputs the commands to the first feedback control system 30.

The first feedback control system 30 to which the first model command has been supplied obtains the first control position error. The first control position error indicates a position error between the first model position command and the first detection position that is obtained from the first sensor 42. Further, the first feedback control system 30 obtains the first synchronization position error, which indicates a difference (an error in position error, synchronization error) between the first control

MOTOR CONTROL APPARATUS ~

BACKGROUND 2 ~ 1. Technical Field Woy Lh “\ \ J 7

The present invention relates to a motor control apparatus. =, AE

Aer 2. Description of the Related Art hs ~

A component mounting machine, such as a mounter, drives a movable portion at = high speed with a motor and positions the movable portion at high accuracy to increase the number of mounted components per unit time. This ensures reducing a production cost taken for component mounting work. For example, a large-sized mounter using a large movable portion with which a large number of printed circuit boards are mountable at the same time probably drives one movable portion at high speed with a plurality of motors.

For example, the motor control apparatus disclosed in JP-A-2003-345442 drives one movable portion with two motors. These two motors are controlled by the motor control models and servo controllers, which are disposed corresponding to the respective two motors. The servo controller actually controls motions of the motor based on the external position command. The motor control models include element models corresponding to the respective elements of the servo controllers. The motor control model obtains the model torque, the model speed, and the model position based on the external position command. The motor control model operates differences between these pieces of model information and the control torque, the control speed and the control position in the actual control, which are fed back from the servo controller. The motor control model returns the differences to the servo controller at a constant proportion.

position error of itself and the second control position error that is obtained by the second x control position error obtainer 71. Additionally, the first feedback control system 30 = obtains a first position synchronization error compensation amount based on the first - synchronization position error. >

The first feedback control system 30 obtains the first control position error after n performing the synchronous compensation process based on the first control position - error and the first position synchronization error compensation amount. The first - feedback control system 30 obtains the first control speed based on the first control = position error after performing the synchronous compensation process. o

The first feedback control system 30 obtains the first control speed error based on the first control speed, the first detection speed, and the first model speed command.

The first feedback control system 30 obtains the first control torque based on the first control speed error.

The first feedback control system 30 obtains the first total control torque based on the first control torque and the first model torque command.

The first torque controller 41 of the first feedback control system 30 controls the first motor 2 based on the first total control torque. The first sensor 42 detects the rotation position of the first motor 2. The first detection speed obtainer 36 obtains the first detection speed based on the rotation position detected by the first sensor 42.

Simultaneous with the supply of the external position command to the first model control system 10, the identical external position command is supplied to the second model control system 50. The second model control system 50 performs the above-described feedback control identical to the first model control system 10.

The second feedback control system 70 to which the second model command is supplied from the second model control system 50 also performs the above-described feedback control identical to the first feedback control system 30.

In the embodiment, two feedback control systems each perform the feedback ~ control on the motors not by the external position command but by the model command. =

Moreover, two model control systems, which generate the model command from the = external position command, include the two-inertia model, which corresponds to the - motion of the mechanical system from the motors to the movable portion when the o movable portion is driven with two motors. Additionally, the two model control =

Ja systems feed back the state of the two-inertia model to restrain vibrations of the table 4 - caused by vibrations of the mechanical system from the motors to the movable portion. :

Thus, the two model control systems restrain the vibrations of the table 4 to stabilize the = table 4.

Accordingly, the two feedback control systems perform the stable feedback control independent of each other to follow the models such that the vibrations of the table 4 is less likely to occur. This allows the two motors to be controlled so as to similarly follow the external position command.

The two feedback control systems can control the two motors based on the common external position command simultaneously input so as to synchronize the two motors with one another. Even if the mechanical system from the motors to the movable portion vibrates, the two feedback control systems can synchronize the two motors with one another while restraining vibrations of the table 4.

Moreover, in this embodiment, the first feedback control system 30 compensates the control error of itself with the difference between the control error of itself (for example, the control position error) and the control error in the second feedback control system 70 (for example, the control position error). While the first feedback control system 30 synchronizes the two motors with one another such that a deviation of control error of itself with respect to the control error in the second feedback control system 70 is less likely to occur, the first feedback control system 30 performs the feedback control on itself. In other words, while the feedback control systems, which are independent of ro each other, control the two motors so as to be independent of each other, the deviation in = control error possibly occurring between the first feedback control system 30 and the 2 second feedback control system 70 can be compensated. That is, the two feedback = control systems can compensate the deviation in the control error possibly occurring ~ between these two feedback control systems. = da

Thus, in this embodiment, the model following control on the two motors that = cooperatively move one movable portion is performed by the common external position = command and using the identical two-inertia model to feed back the state so as to - compensate the vibrations of the mechanical system from the motors to the table 4.

This allows making the torque commands provided to the two feedback control systems to be identical between all axes. Even if the mechanical system from the motors to the table 4 possibly vibrates, the vibrations of the table 4 can be restrained. Therefore, the control such that the deviation is less likely to occur between the control errors in the two feedback control systems can be performed.

Due to another cause, a slight deviation between control errors may occur between the two feedback control systems. In this embodiment, this deviation is compensated between the two feedback control systems. Accordingly, the control systems with two motors perform controls where a control less likely to generate a synchronization deviation caused by vibrations and a control for restraining the synchronization deviation are duplicated. This ensures enhancing the synchronization accuracy of two motors to control one movable portion with the two motors.

Consequently, in this embodiment, even if the vibrations possibly occur between the motors and the table 4 in the machine that drives one movable portion with two motors, the vibrations of the table 4 can be restrained. This ensures enhancing the following capability of the two motors to commands. Further, the synchronization accuracy between the two motors can be ensured, and as a result, the high-speed and high- ~ accuracy positioning can be performed. -

In the example described in the embodiment, two sets of model control systems . and feedback control systems are used to drive the movable portion with two motors. -

In the example, a synchronization position error obtainer, a position synchronization = compensator, and a synchronization compensation position error obtainer are applied to - the first feedback control system. Besides, the synchronization position error obtainer, - pw] the position synchronization compensator, and the synchronization compensation = position error obtainer may be applicable to the second feedback control system. =

Furthermore, the movable portion may be driven with three or more motors. In this case, the model control systems and feedback control systems may be disposed basically by the identical number of sets to the motors.

N (N is a natural number of two or more) pieces of motors may drive the movable portion. In this case, the synchronization position error obtainers, the position synchronization compensators, and the synchronization compensation position error obtainers may be disposed in (N — 1) pieces of feedback control systems. It is only necessary for (N — 1) pieces of the synchronization position error obtainers in (N — 1) pieces of the feedback control systems to, for example, obtain a synchronization position error based on these respective control position errors and the control position error of the remaining one feedback control system.

Fourth Embodiment

Fig. 4 is a block diagram of the motor control apparatus 1 according to a fourth embodiment of the present invention. The motor control apparatus 1 illustrated in Fig. 4 differs from the motor control apparatus 1 illustrated in Fig. 3 in that the second feedback control system 70 includes a second synchronization position error obtainer 72, a second position synchronization compensator 73, and a second synchronization compensation position error obtainer 74. o

The second synchronization position error obtainer 72, the second position = synchronization compensator 73, and the second synchronization compensation position : error obtainer 74 correspond to the first synchronization position error obtainer 32, the - first position synchronization compensator 33, and the first synchronization = compensation position error obtainer 34. -

The second synchronization position error obtainer 72 obtains a second - synchronization position error based on the second control position error, which is = obtained by the second control position error obtainer 71, and the first control position : error, with is obtained by the first control position error obtainer 31. The second synchronization position error indicates a difference (a synchronization error) between these control position errors. The second synchronization position error, for example, may be operated by subtracting another first control position error from the second control position error that is obtained by the second control position error obtainer 71.

In this case, the synchronization error of the second feedback control system 70 with respect to the first feedback control system 30 is obtained.

The second position synchronization compensator 73 obtains a second position synchronization error compensation amount based on the second synchronization position error. In this embodiment, a deviation in control position errors between the first feedback control system 30 and the second feedback control system 70 is mutually compensated. Therefore, the proportional controller may be used for the first position synchronization compensator 33 and the second position synchronization compensator 73.

The second synchronization compensation position error obtainer 74 obtains the second control position error after performing the synchronous compensation process based on the second control position error, which is the control position error in the second feedback control system 70, and the second position synchronization error - — compensation amount, which is a synchronous position error between the two feedback = control systems. The second control position error after performing the synchronous - compensation process, for example, may be an addition value (a summed value) of the on second control position error and the second position synchronization error compensation amount. c

The second position controller 75 obtains a second control speed based on the _ second control position error after performing the synchronous compensation process. =

J

The second position controller 75 obtains the second control speed according to the oe control position error in the second feedback control system 70 and the synchronous position error in the second feedback control system 70 using the first feedback control system 30 as a criterion. If the control position of the second feedback control system 70 delays with respect to the control position of the first feedback control system 30, the second control speed increases.

The configurations and behaviors of the motor control apparatus 1 illustrated in

Fig. 4 other than these are similar to those illustrated in Fig. 3, and therefore the description thereof is omitted here.

In this embodiment, the first feedback control system 30 and the second feedback control system 70 can mutually compensate the position error between two axes (for example, a deviation in control position error). Consequently, even if the control responses from the individual feedback control systems are not high, the position error between the axes can be decreased and the synchronization accuracy can be increased. This embodiment can be expected to provide the synchronization accuracy further higher than the third embodiment.

In view of this, for example, by causing the first feedback control system 30 and the second feedback control system 70 to follow the identical vibration model, the synchronization error is less likely to occur and the synchronization error between the o axes caused by other causes can be efficiently restrained compared with the third = embodiment. ~

Thus, in this embodiment, the individual model control systems are provided using the identical two-inertia model in the machine that drives one movable portion with a plurality of (here, two) motors. Further, the actual feedback control systems = perform control so as to follow this model. Accordingly, even if vibrations possibly - occur between the motors and the table 4, vibrations between the motors and the table 4 @ can be restrained. Thus, the synchronization accuracy between the two motors can be © ensured, and consequently, the high-speed and high-accuracy positioning can be performed.

The motor control apparatus according to embodiments of the present invention as described above may be any of the following first to thirteenth motor control apparatuses.

The first motor control apparatus (1) is a motor control apparatus (1) for cooperatively driving one movable portion (4) with N (N: natural number of two or more) pieces of motors (2, 3), the motors (2, 3) being driven based on a common external position command. The motor control apparatus (1) includes: a model control system (10, 50) configured to feed back a state to restrain an influence of vibrations to the movable portion (4), the model control system (10, 50) being configured to generate a model command including a model position command based on the external position command; and N pieces of feedback control systems (30, 70) disposed corresponding to

N pieces of the motors (2, 3) on a one-to-one basis, the feedback control systems (30, 70) being configured to perform a feedback control on the respective motors (2, 3) based on the model command. (N — 1) pieces of the feedback control systems (30, 70) are configured to compensate a control error when controlling each of the motors (2, 3) with a difference between each of the control errors in the feedback control systems and a ~ control error in the remaining one feedback control system (30, 70). =

The second motor control apparatus (1) according to the first motor control — apparatus is configured as follows. The model control system (10, 50) includes a = movable portion (4) model and a machine table model, the movable portion (4) model - corresponding to a motion of the movable portion (4) driven by the motors (2, 3), the - machine table model corresponding to a motion of a machine table to which the motors - (2, 3) and the movable portion (4) are mounted, the model control system being = configured to feed back a state of the machine table model to restrain vibrations between the machine table and the movable portion (4) caused by vibrations of the machine table.

The model control system (10, 50) includes a model position adder (20, 60), the model position adder being configured to operate a position obtained by adding a position of the movable portion (4) model and a position of the machine table model as a model position to be output as the model position command.

The third motor control apparatus (1) according to the second motor control apparatus is configured as follows. The model control system (10, 50) includes a model position error operator (11, 51), the model position error operator being configured to subtract the model position output from the model position adder (20, 60) from the external position command to operate a model position error. N pieces of the feedback control systems (30, 70) each include a control position error obtainer (31, 71), the control position error obtainer being configured to obtain a control position error based on the model position command and a position of each of the motors (2, 3) detected by a sensor (42, 82), the control position error indicating a position error in each of the motors 2, 3).

The fourth motor control apparatus (1) according to the third motor control apparatus is configured as follows. (N — 1) pieces of the feedback control systems (30,

70) each include a synchronization position error obtainer (32, 72), the synchronization < position error obtainer being configured to obtain a difference between each control ~ position error and the control position error in the remaining one feedback control system. =

The feedback control system (30, 70) is configured to compensate the control position > error when controlling each of the motors (2, 3) with a difference between each of the - control position errors in the feedback control systems and the control position error in = the remaining one feedback control system (30, 70). =

The fifth motor control apparatus (1) according to the fourth motor control ® apparatus is configured as follows. The model control system (10, 50) includes: a - model position controller (12, 52) configured to operate a model speed based on the model position error; a model speed operator (13, 53) configured to operate a model detection speed as a model speed command based on the model position output from the model position adder (20, 60), the model speed command being one of the model command; a model speed error operator (14, 54) configured to subtract the model detection speed from the model speed to operate a model speed error; a model speed controller (15, 55) configured to operate a model torque based on the model speed error; a model torque error operator (16, 56) configured to subtract a state feedback amount from the model torque to operate the model torque after performing a state compensation as a model torque command, the model torque command being one of the model command; a model low-pass filter (17, 57) configured to perform a low-pass filter process on the model torque after performing the state compensation, the model low-pass filter being configured to output the model torque to the movable portion (4) model and the machine table model; and a state feedback amount operator configured (21, 61) to operate the state feedback amount according to the state of the machine table model. N pieces of the feedback control systems (30, 70) each include: a position controller (35, 75) configured to obtain a control speed based on the control position error after performing a compensation process; a detection speed obtainer (36, 76) configured to ~ obtain a detection speed based on the position detected by the sensor (42, 82), the sensor = being configured to detect the position of each of the motors (2, 3); a control speed error o obtainer (37, 77) configured to obtain a control speed error based on the control speed, - the detection speed, and the model speed command, the control speed error being obtained by adding the model speed command to a speed error between the control speed - and the detection speed; a speed controller (38, 78) configured to obtain a control torque - from the control speed error; a control torque obtainer (39, 79) configured to obtain a © total control torque, the total control torque indicating a sum of the control torque and the o model torque command; a control low-pass filter (40, 80) configured to perform a low- pass filter process on the total control torque; and a torque controller (41, 81) configured to control the respective motors (2, 3) based on the total control torque after performing the low-pass filter process.

The sixth motor control apparatus (1) according to the first motor control apparatus is configured as follows. The model control system (10, 50) includes a multi- inertia model (95, 115), the multi-inertia model corresponding to a motion of a mechanical system from the motors (2, 3) to the movable portion (4), the model control system being configured to feed back a state of the multi-inertia model (95, 115) to restrain vibrations of the movable portion (4) caused by vibrations of the mechanical system, and the multi-inertia model (95, 115) is configured to operate a model position, the model position being output as the model position command.

The seventh motor control apparatus (1) according to the sixth motor control apparatus is configured as follows. The model control system (10, 50) includes a model position error operator (11, 51), the model position error operator being configured to subtract the model position output from the multi-inertia model (95, 115) from the external position command to operate a model position error. N pieces of the feedback

Thus, the motor control model operates the control error in the servo controller ~ and returns the control error to the servo controller. This allows the servo controller to = control the motions of the motor following the model torque, the model speed, and the model position, which are obtained by the motor control model. o

Thus, the motor control apparatus disclosed in JP-A-2003-345442 determines " the error between the motor control model and control by the servo controller as a - disturbance, and performs phase compensation on the error. This restrains a deviation ~ between the model and the control by the servo controller. Therefore, it is considered = that the use of the identical model between the control systems of the plurality of motors ensures restraining the deviation (the synchronization error) between the axes. : Unlike the technique disclosed in JP-A-2003-345442, one motor may drive one movable portion. In this case, the movable portion possibly yaws so as to be inclined with respect to the driving direction of the motor. With the technique disclosed in JP-

A-2003-345442, two motors drive one movable portion. It is considered that this can also be expected to restrain this yaw.

However, with an actual mechanical system, in the case of using the plurality of motors, for example, ball screws, which drive the movable portion, or the like possibly cause torsional vibrations. Additionally, a machine table to which the plurality of motors and the movable portion are mounted may vibrate. This may vibrate the movable portion. The method disclosed in JP-A-2003-345442 does not consider a function to restrain these torsional vibrations and machine table vibrations. Therefore, for example, in the case of low rigidity of the mechanical system, this causes a problem that it is difficult to sufficiently restrain these vibrations.

Additionally, in the case where the machine table vibrations or torsional vibrations possibly occur actually, a control for restraining the vibrations is performed.

Consequently, this makes it difficult to sufficiently enhance control responses from servo 2 -....._______

control systems (30, 70) each include a control position error obtainer (31, 71), the - control position error obtainer being configured to obtain a control position error based = on the model position command and a position of each of the motors (2, 3) detected by a = sensor (42, 82), the control position error indicating the position error in each of the = motors. -

The eighth motor control apparatus (1) according to the seventh motor control © apparatus is configured as follows. (N — 1) pieces of the feedback control systems (30, = 70) each include a synchronization position error obtainer (32, 72), the synchronization s position error obtainer being configured to obtain a difference between each of the e control position errors in the feedback control systems and the control position error in the remaining one feedback control system (30, 70), and the feedback control system is configured to compensate the control position error when controlling each of the motors (2, 3) with a difference between each of the control position errors in the respective feedback control systems and the control position error in the remaining one feedback control system (30, 70).

The ninth motor control apparatus (1) according to the eighth motor control apparatus is configured as follows. The model control system (10, 50) includes: a model position controller (12, 52) configured to operate a model speed based on the model position error; a state compensation model speed error operator (14, 54) configured to subtract a state feedback amount of a speed and a model speed operated by the multi-inertia model (95, 115) from the model speed to operate a model speed error after performing a state compensation; a model speed controller (15, 55) configured to operate a model torque based on the model speed error after performing the state compensation; and a state compensation model torque error operator (16, 56) configured to subtract a state feedback amount of acceleration and a torsional torque operated by the multi-inertia model (95, 115) from the model torque, the state compensation model torque error operator being configured to operate a model torque error after performing = the state compensation to output the model torque error to the multi-inertia model (95, 115). N pieces of the feedback control systems (30, 70) each include: a position ~ controller (35, 75) configured to obtain a control speed based on the control position o : 5 error after performing a compensation process; a detection speed obtainer (36, 76) configured to obtain a detection speed based on the position detected by the sensor (42, - 82), the sensor being configured to detect the position of each of the motors (2, 3); a - control speed error obtainer (37, 77) configured to obtain a control speed error based on ® the control speed, the detection speed, and the model speed command, the model speed - command being operated in the multi-inertia model (95, 115) as one of the model command, the control speed error being obtained by adding the model speed command to a speed error between the control speed and the detection speed; a speed controller (38, 78) configured to obtain a control torque from the control speed error; a control torque obtainer (39, 79) configured to obtain a total control torque, the total control torque indicating a sum of the control torque and the model torque command, the model torque command being operated in the multi-inertia model (95, 115) as one of the model command; and a torque controller (41, 81) configured to control the respective motors (2, 3) based on the total control torque.

The tenth motor control apparatus (1) according to any of the first to ninth motor control apparatuses is configured as follows. The identical model command is simultaneously input from the model control system (10, 50) to N pieces of the feedback control systems (30, 70).

The eleventh motor control apparatus (1) according to any of the first to tenth motor control apparatuses is configured as follows. N pieces of the model control systems (10, 50) are disposed to correspond to N pieces of the feedback control systems (30, 70) on a one-to-one basis, and N pieces of the model control systems (10, 50) have an identical feedback loop, the model control systems being configured to generate the ~ identical model command based on the common external position command. =

The twelfth motor control apparatus (1) according to any of the first to eleventh ~ motor control apparatuses is configured as follows. The feedback control systems o comprises two feedback control systems (30, 70), and the two feedback control systems in (30, 70) are each configured to compensate a control error to control the motors (2, 3) - with a difference between the respective control errors in the feedback control systems - and the control error in another feedback control system (30, 70). @

The thirteenth motor control apparatus (1) according to any of the first to twelfth A motor control apparatuses is configured as follows. A characteristic equation with respect to an equation of state of the model control system (10, 50) has a multiple root.

The present invention also relates to a motor control apparatus that includes a plurality of motors cooperatively driving one movable portion to position the movable portion at high speed and high accuracy.

The embodiments of the present invention may be the following fourteenth to twenty sixth motor control apparatuses.

The fourteenth motor control apparatus is a motor control apparatus for cooperatively moving one movable portion with N (N: natural number of two or more) pieces of motors. The motors are driven by a common external position command.

The motor control apparatus includes a model control system and N pieces of feedback control systems. The model control system is configured to feed back a state to restrain an influence of vibrations to the movable portion. The model control system is configured to generate a model command including a model position command from the external position command. N pieces of the feedback control systems are disposed corresponding to N pieces of the motors on a one-to-one basis. The feedback control systems are configured to perform a feedback control on the respective motors by the model command. (N — 1) pieces of the feedback control systems are configured to ~ compensate a control error when controlling the respective motors with a difference with = a control error in the remaining one feedback control system. ~

The fifteenth motor control apparatus according to the fourteenth motor control - apparatus is configured as follows. The model control system includes a movable portion model and a machine table model. The movable portion model corresponds to a = motion of the movable portion driven by the motors. The machine table model - corresponds to a motion of a machine table to which the motors and the movable portion = are mounted. The model control system is configured to feed back a state of the 5 machine table model to restrain vibrations between the machine table and the movable portion caused by vibrations of the machine table. The model control system includes a model position adder. The model position adder is configured to operate a position obtained by adding a position of the movable portion model and a position of the machine table model as a model position to be output as the model position command.

The sixteen motor control apparatus according to the fifteenth motor control apparatus is configured as follows. The model control system includes a model position error operator. The model position error operator is configured to subtract the model position output from the model position adder from the external position command to operate a model position error. N pieces of the feedback control systems each include a control position error generator. The control position error generator is configured to generate a control position error based on the model position command and a position of each of the motors detected by a sensor, which detects the position. The control position error indicates these position errors.

The seventeenth motor control apparatus according to the sixteen motor control apparatus is configured as follows. (N — 1) pieces of the feedback control systems each include a synchronization position error generator. The synchronization position error generator is configured to generate a difference between each of the control position = errors and the control position error in the remaining one feedback control system. The = feedback control system is configured to compensate the control position error when - oe controlling each of the motors with a difference with the control position error in the a remaining one feedback control system. -

The eighteenth motor control apparatus according to the seventeenth motor = control apparatus is configured as follows. The model control system includes a model Ty position controller, a model speed operator, a model speed error operator, a model speed = controller, a model torque error operator, a model low-pass filter, and a state feedback ~ amount operator. The model position controller is configured to operate a model speed from the model position error. The model speed operator is configured to operate a model detection speed as a model speed command from the model position output from the model position adder. The model speed command is one of the model command.

The model speed error operator is configured to subtract the model detection speed from the model speed to operate a model speed error. The model speed controller is configured to operate a model torque from the model speed error. The model torque error operator is configured to subtract a state feedback amount from the model torque to operate the model torque after performing a state compensation as a model torque command. The model torque command is one of the model command. The model low-pass filter is configured to perform a low-pass filter process on the model torque after performing the state compensation. The model low-pass filter is configured to output the model torque to the movable portion model and the machine table model.

The state feedback amount operator is configured to operate the state feedback amount according to the state of the machine table model. N pieces of the feedback control systems each include a position controller, a detection speed generator, a control speed error generator, a speed controller, a control torque generator, a control low-pass filter,

and a torque controller. The position controller is configured to generate a control > speed from the control position error after performing a compensation process. The = detection speed generator is configured to generate a detection speed from the position © detected by the sensor. The sensor is configured to detect the position of each of the o motors. The control speed error generator is configured to generate a control speed error based on the control speed, the detection speed, and the model speed command. -

The control speed error is obtained by adding the model speed command to a speed error - between the control speed and the detection speed. The speed controller is configured © to generate a control torque from the control speed error. The control torque generator is configured to generate a total control torque based on the control torque and the model torque command. The total control torque indicates a sum of the control torque and the model torque command. The control low-pass filter is configured to perform a low- pass filter process on the total control torque. The torque controller is configured to control the respective motors based on the total control torque after performing the low- pass filter process.

The nineteenth motor control apparatus according to the fourteenth motor control apparatus is configured as follows. The model control system includes a multi- inertia model. The multi-inertia model corresponds to a motion of a mechanical system from the motors to the movable portion. The model control system is configured to feed back a state of the multi-inertia model to restrain vibrations of the movable portion caused by vibrations of the mechanical system. The multi-inertia model is configured to operate a model position. The model position is output as the model position command.

The twentieth motor control apparatus according to the nineteenth motor control apparatus is configured as follows. The model control system includes a model position error operator. The model position error operator is configured to subtract the 52

Lo model position output from the multi-inertia model from the external position command ro to operate a model position error. N pieces of the feedback control systems each - include a control position error generator. The control position error generator is configured to generate a control position error based on the model position command and = aposition of each of the motors detected by a sensor, which detects the position. The control position error indicates these position errors. =

I.

The twenty first motor control apparatus according to the twentieth motor - control apparatus is configured as follows. (N — 1) pieces of the feedback control systems each include a synchronization position error generator. The synchronization > position error generator is configured to generate a difference between each of the control position errors and the control position error in the remaining one feedback control system. The feedback control system is configured to compensate the control position error when controlling each of the motors with a difference with the control position error in the remaining one feedback control system.

The twenty second motor control apparatus according to the twenty first motor control apparatus is configured as follows. The model control system includes a model position controller, a state compensation model speed error operator, a model speed controller, and a state compensation model torque error operator. The model position controller is configured to operate a model speed from the model position error. The state compensation model speed error operator is configured to subtract a state feedback amount of a speed and a model speed operated by the multi-inertia model from the model speed to operate a model speed error after performing a state compensation. The model speed controller is configured to operate a model torque from the model speed error after performing the state compensation. The state compensation model torque error operator is configured to subtract a state feedback amount of acceleration and a torsional torque operated by the multi-inertia model from the model torque. The state compensation model torque error operator is configured to thus operate a model torque - error after performing the state compensation to output the model torque error to the = multi-inertia model. N pieces of the feedback control systems each include a position vs controller, a detection speed generator, a control speed error generator, a speed controller, - acontrol torque generator, and a torque controller. The position controller is configured nN to generate a control speed from the control position error after performing a - compensation process. The detection speed generator is configured to generate a - detection speed from the position detected by the sensor. The sensor is configured to = detect the position of each of the motors. The control speed error generator is © configured to generate a control speed error based on the control speed, the detection speed, and the model speed command. The model speed command is operated in the multi-inertia model as one of the model command. The control speed error is obtained by adding the model speed command to a speed error between the control speed and the detection speed. The speed controller is configured to generate a control torque from the control speed error. The control torque generator is configured to generate a total control torque based on the control torque and the model torque command. The total control torque indicates a sum of the control torque and the model torque command.

The model torque command is operated in the multi-inertia model as one of the model command. The torque controller is configured to control the respective motors based on the total control torque.

The twenty third motor control apparatus according to any one of the fourteenth to the twenty second motor control apparatuses is configured as follows. The identical model command is simultaneously input from the model control system to N pieces of the feedback control systems.

The twenty fourth motor control apparatus according to any one of the fourteenth to the twenty third motor control apparatuses is configured as follows. N pieces of the model control systems are disposed to correspond to N pieces of the . feedback control systems on a one-to-one basis. N pieces of the model control systems configure an identical feedback loop. The model control systems are configured to generate the identical model command from the common external position command. -

The twenty fifth motor control apparatus according to any one of the fourteenth to the twenty fourth motor control apparatuses is configured as follows. A number of =

Jo the feedback control systems is two. The two feedback control systems are each - configured to mutually compensate a control error to control the motors with a difference = with the control error in another feedback control system. -

The twenty sixth motor control apparatus according to any one of the fourteenth to the twenty fifth motor control apparatuses is configured as follows. A characteristic equation with respect to an equation of state of the model control system has a multiple root.

With the fourteenth motor control apparatus, N pieces of the feedback control systems each perform the feedback control on the motors not by the external position command but by the model command including the model position. Moreover, the model control systems, which generate the model command including the model position command from the external position command, feed back the state to restrain the influence of vibrations to the movable portion.

Therefore, N pieces of the feedback control systems perform the feedback control following the models to restrain the influence of vibrations independent of each other. This allows N pieces of the motors to be controlled so as to similarly follow the external position command.

N pieces of the feedback control systems ensure controlling N pieces of the motors by the common external position command so as to synchronize N pieces of the motors with one another. For example, assume that, as a result of vibrations of the machine table to which the movable portion or the like is mounted or vibrations of the - movable portion to the motors, the vibrations affect the movable portion. In this case, ~ while the influence is restrained, N pieces of the motors can be synchronized which one - another. ~

Moreover, in the fourteenth motor control apparatus, (N — 1) pieces of the “ feedback control systems compensate the control errors of the respective feedback a. control systems with the difference with the control error in the remaining one feedback = control system. While (N — 1) pieces of the feedback control systems perform o synchronization such that a deviation of each control error with respect to the control error in the one feedback control system is less likely to occur, (N — 1) pieces of the feedback control systems each perform the feedback control. That is, while the feedback control systems independent of each other control N pieces of the motors so as to be independent of each other, this motor control apparatus ensures compensating the deviation in control error possibly occurring between the one feedback control system and (N — 1) pieces of the feedback control systems. The one feedback control system and (N — 1) pieces of the feedback control systems can compensate the deviation in the control errors possibly occurring between N pieces of these feedback control systems.

Thus, this fourteenth motor control apparatus performs a model following control on the plurality of motors that cooperatively move the one movable portion by the common external position command and using the identical model to feed back the state so as to restrain the influence of vibrations to the movable portion. This allows making the torque commands provided to the feedback control systems to be identical between all axes. Accordingly, for example, even if the machine table vibrations occur or the movable portion vibrates to the motors, this motor control apparatus ensures restraining the influence of the vibrations to the movable portion caused by such circumstance and improving following capability to the commands while performing the 56 -....______

controllers on individual axes. If the control responses from the servo controllers on the o individual axes are not high, it is difficult to sufficiently restrain an error between a - model and the servo controllers (control by the servo controllers). Ifit is difficult to 2 sufficiently restrain the error between the model and the servo controllers, enhancing - synchronization accuracy between the axes becomes difficult. "

The present invention has been made to solve the above-described problems. -

An object of the present invention is to provide the following motor control apparatus. ”

With a machine that drives one movable portion with a plurality of motors, the motor © control apparatus restrains an influence of vibrations to the movable portion. This o ensures high synchronization accuracy of the plurality of motors. Consequently, with this motor control apparatus, high-speed and high-accuracy positioning can be performed.

SUMMARY

A motor control apparatus according to an aspect of the present invention (the present motor control apparatus) for cooperatively driving one movable portion with N (N: natural number of two or more) pieces of motors, the motors being driven based on a common external position command, includes: a model control system configured to feed back a state to restrain an influence of vibrations to the movable portion, the model control system being configured to generate a model command including a model position command based on the external position command; and N pieces of feedback control systems disposed corresponding to N pieces of the motors on a one-to-one basis, the feedback control systems being configured to perform a feedback control on the ; respective motors based on the model command. (N — 1) pieces of the feedback control systems are configured to compensate a control error when controlling the respective motors with a difference between each of the control errors in the feedback control systems and a control error in the remaining one feedback control system. 3 _—

control such that the deviation is less likely to occur between the control errors in the o plurality of feedback control systems. Additionally, the motor control apparatus = compensates a slight deviation in control errors possibly occurring between N pieces of . the feedback control systems due to another cause between N pieces of the feedback - control systems. Accordingly, the control systems with N pieces of the motors perform controls where a control less likely to generate a synchronization deviation by restraining - the influence of vibrations to the movable portion and a control that restrains the - synchronization deviation are duplicated. This ensures enhancing the synchronization < accuracy of the plurality of motors to control the one movable portion with the plurality o of motors. This ensures achieving high-speed, high-accuracy positioning.

The foregoing detailed description has been presented for the purposes of illustration and description. Many modifications and variations are possible in light of the above teaching. It is not intended to be exhaustive or to limit the subject matter described herein to the precise form disclosed. Although the subject matter has been described in language specific to structural features and/or methodological acts, it is to be understood that the subject matter defined in the appended claims is not necessarily limited to the specific features or acts described above. Rather, the specific features and acts described above are disclosed as example forms of implementing the claims appended hereto.

With the motor control apparatus, N pieces of the feedback control systems each ° perform the feedback control on the motors not by the external position command but by o the model command including the model position. Moreover, the model control ~ systems, which generate the model command including the model position command - from the external position command, feed back the state to restrain the influence of = vibrations to the movable portion. -

Therefore, N pieces of the feedback control systems perform the feedback ” control following the models to restrain the influence of vibrations independent of each = other. This allows N pieces of the motors to be controlled so as to similarly follow the = external position command.

N pieces of the feedback control systems can control N pieces of the motors based on the common external position command so as to synchronize N pieces of the motors with one another. For example, as a result of vibrations of the machine table to which the movable portion or the like is mounted or vibrations of the movable portion to the motors, the vibrations may affect the movable portion. In this case, while the influence of these vibrations is restrained, N pieces of the motors can be synchronized with one another.

Moreover, in the motor control apparatus, (N — 1) pieces of the feedback control systems compensate the control errors of the respective feedback control systems with the difference between the respective control errors and the control error in the remaining one feedback control system. While (N — 1) pieces of the feedback control systems synchronize N pieces of the motors with one another such that a deviation of each control error with respect to the control error in the one feedback control system is less likely to occur, (N — 1) pieces of the feedback control systems each perform the feedback control. That is, while the feedback control systems, which are independent of each other, control N pieces of the motors so as to be independent of each other, this motor ee ———— EE —— EE control apparatus can compensate the deviation in control error possibly occurring between the one feedback control system and (N — 1) pieces of the feedback control = systems. That is, the one feedback control system and (N — 1) pieces of the feedback - control systems can compensate the deviation in the control errors possibly occurring > between N pieces of these feedback control systems.

Thus, this motor control apparatus performs a model following control on the = plurality of motors that cooperatively moves one movable portion based on the common _ external position command and using the identical model to feed back the state so as to = restrain the influence of vibrations to the movable portion. This allows making the - torque commands provided to the feedback control systems to be identical between all axes. Accordingly, for example, even if the machine table vibrations occur or the movable portion vibrates to the motors, this motor control apparatus can restrain the influence of the vibrations to the movable portion caused by such circumstance. This enhances the following capability to the commands. Accordingly, the control such that the deviation is less likely to occur between the control errors in the plurality of feedback control systems can be performed.

Due to another cause, a slight deviation between control errors possibly occurs between N pieces of the feedback control systems. This motor control apparatus compensates this deviation between N pieces of the feedback control systems.

Accordingly, the control systems with N pieces of the motors perform controls where a control less likely to generate a synchronization deviation by restraining the influence of vibrations to the movable portion and a control for restraining the synchronization deviation are duplicated. This can enhance the synchronization accuracy of the plurality of motors to drive (control) the one movable portion with the plurality of motors. Consequently, the high-speed and high-accuracy positioning can be performed.

BRIEF DESCRIPTION OF THE DRAWINGS 0

Fig. 1 is a block diagram of a motor control apparatus according to a first = embodiment of the present invention; -

Fig. 2 is a block diagram of a motor control apparatus according to a second - embodiment of the present invention; in

Fig. 3 is a block diagram of a motor control apparatus according to a third - embodiment of the present invention; and ~

Fig. 4 is a block diagram of a motor control apparatus according to a fourth = embodiment of the present invention. -

DESCRIPTION OF THE EMBODIMENTS

In the following detailed description, for purpose of explanation, numerous specific details are set forth in order to provide a thorough understanding of the disclosed embodiments. It will be apparent, however, that one or more embodiments may be practiced without these specific details. In other instances, well-known structures and devices are schematically shown in order to simplify the drawing,

The following describes embodiments of the present invention with reference to the drawings.

First Embodiment

Fig. 1 is a block diagram of a motor control apparatus 1 according to a first embodiment of the present invention. In the motor control apparatus 1 in Fig. 1, two motors, a first motor 2 and a second motor 3, cooperatively drive one movable portion.

Accordingly, the motor control apparatus 1 ensures positioning the movable portion at high speed and high accuracy.

As illustrated in Fig. 1, the motor control apparatus 1 includes a first model control system 10, a first feedback control system 30, a second model control system 50,

Claims (13)

: Co Zh ME What is claimed is: ¥ f py

1. A motor control apparatus for cooperatively driving one movable portion with Np x ¢ (N: natural number of two or more) pieces of motors, the motors being driven based on a ©» - common external position command, the motor control apparatus comprising: = a model control system configured to feed back a state to restrain an influence ~ of vibrations to the movable portion, the model control system being configured to © iF generate a model command including a model position command based on the external = position command; and = N pieces of feedback control systems disposed corresponding to N pieces of the ne motors on a one-to-one basis, the feedback control systems eing configured to perform a feedback control on the respective motors based on the model command, wherein (N — 1) pieces of the feedback control systems are configured to compensate a control error when controlling the respective motors with a difference between each of the control errors in the feedback control systems and a control error in the remaining one feedback control system.

2. The motor control apparatus according to claim 1, wherein the model control system includes a movable portion model and a machine table model, the movable portion model corresponding to a motion of the movable portion driven by the motors, the machine table model corresponding to a motion of a machine table to which the motors and the movable portion are mounted, the model control system being configured to feed back a state of the machine table model to restrain vibrations between the machine table and the movable portion caused by vibrations of the machine table, and the model control system includes a model position adder, the model position adder being configured to operate a position obtained by adding a position of the movable portion model and a position of the machine table model as a model position to be output as the model position command. te .

3. The motor control apparatus according to claim 2, wherein 7 the model control system includes a model position error operator, the model - position error operator being configured to subtract the model position output from the © model position adder from the external position command to operate a model position = error, and = N pieces of the feedback control systems each include a control position error wr obtainer, the control position error obtainer being configured to obtain a control position error based on the model position command and a position of each of the motors detected by a sensor, the control position error indicating a position error in each of the motors.

4. The motor control apparatus according to claim 3, wherein (N — 1) pieces of the feedback control systems each include a synchronization position error obtainer, the synchronization position error obtainer being configured to obtain a difference between each control position error and the control position error in the remaining one feedback control system, and the feedback control system is configured to compensate the control position error when controlling each of the motors with a difference between each of the control position errors in the feedback control systems and the control position error in the remaining one feedback control system.

5. The motor control apparatus according to claim 4, wherein the model control system includes: a model position controller configured to operate a model speed based on the model position error; - a model speed operator configured to operate a model detection speed = as a model speed command based on the model position output from the model position pi adder, the model speed command being one of the model command, = a model speed error operator configured to subtract the model detection speed from the model speed to operate a model speed error; © a model speed controller configured to operate a model torque based on _ the model speed error; = a model torque error operator configured to subtract a state feedback o amount from the model torque to operate the model torque after performing a state compensation as a model torque command, the model torque command being one of the model command; a model low-pass filter configured to perform a low-pass filter process on the model torque after performing the state compensation, the model low-pass filter being configured to output the model torque to the movable portion model and the machine table model; and a state feedback amount operator configured to operate the state feedback amount according to the state of the machine table model, wherein N pieces of the feedback control systems each include: a position controller configured to obtain a control speed based on the control position error after performing a compensation process; a detection speed obtainer configured to obtain a detection speed based on the position detected by the sensor, the sensor being configured to detect the position of each of the motors; a control speed error obtainer configured to obtain a control speed error based on the control speed, the detection speed, and the model speed command, the control speed error being obtained by adding the model speed command to a speed error - between the control speed and the detection speed; = a speed controller configured to obtain a control torque from the control o — speed error; : a a control torque obtainer configured to obtain a total control torque, the ~ total control torque indicating a sum of the control torque and the model torque = command; oo a control low-pass filter configured to perform a low-pass filter process = on the total control torque; and ~ a torque controller configured to control the respective motors based on the total control torque after performing the low-pass filter process.

6. The motor control apparatus according to claim 1, wherein the model control system includes a multi-inertia model, the multi-inertia model corresponding to a motion of a mechanical system from the motors to the movable portion, the model control system being configured to feed back a state of the multi- inertia model to restrain vibrations of the movable portion caused by vibrations of the mechanical system, and the multi-inertia model is configured to operate a model position, the model position being output as the model position command.

7. The motor control apparatus according to claim 6, wherein the model control system includes a model position error operator, the model position error operator being configured to subtract the model position output from the multi-inertia model from the external position command to operate a model position error, and

N pieces of the feedback control systems each include a control position error ~ obtainer, the control position error obtainer being configured to obtain a control position error based on the model position command and a position of each of the motors detected . by a sensor, the control position error indicating the position error in each of the motors. o ee

8. The motor control apparatus according to claim 7, wherein = (N — 1) pieces of the feedback control systems each include a synchronization ~ position error obtainer, the synchronization position error obtainer being configured to = obtain a difference between each of the control position errors in the feedback control co systems and the control position error in the remaining one feedback control system, and the feedback control system is configured to compensate the control position error when controlling each of the motors with a difference between each of the control position errors in the feedback control systems and the control position error in the remaining one feedback control system.

9. The motor control apparatus according to claim 8, wherein the model control system includes: a model position controller configured to operate a model speed based on the model position error; a state compensation model speed error operator configured to subtract a state feedback amount of a speed and a model speed operated by the multi-inertia model from the model speed to operate a model speed error after performing a state compensation; a model speed controller configured to operate a model torque based on the model speed error after performing the state compensation; and a state compensation model torque error operator configured to subtract oo a state feedback amount of acceleration and a torsional torque operated by the multi- = inertia model from the model torque, the state compensation model torque error operator = being configured to operate a model torque error after performing the state compensation = to output the model torque error to the multi-inertia model, wherein vr N pieces of the feedback control systems each include: =. a position controller configured to obtain a control speed based on the 5 control position error after performing a compensation process; = a detection speed obtainer configured to obtain a detection speed based ® on the position detected by the sensor, the sensor being configured to detect the position of each of the motors; a control speed error obtainer configured to obtain a control speed error based on the control speed, the detection speed, and the model speed command, the model speed command being operated in the multi-inertia model as one of the model command, the control speed error being obtained by adding the model speed command to a speed error between the control speed and the detection speed; a speed controller configured to obtain a control torque from the control speed error; a control torque obtainer configured to obtain a total control torque, the total control torque indicating a sum of the control torque and the model torque command, the model torque command being operated in the multi-inertia model as one of the model command; and a torque controller configured to control the respective motors based on the total control torque.

10. The motor control apparatus according to any one of claims 1 to 9, wherein the identical model command is simultaneously input from the model control system to N pieces of the feedback control systems. > po

11. The motor control apparatus according to any one of claims 1 to 10, wherein . N pieces of the model control systems are disposed to correspond to N pieces of ~ the feedback control systems on a one-to-one basis, and = N pieces of the model control systems have an identical feedback loop, the - model control systems being configured to generate the identical model command based on the common external position command. © 0

12. The motor control apparatus according to any one of claims 1 to 11, wherein the feedback control systems comprises two feedback control systems, and the two feedback control systems are each configured to compensate a control error to control the motors with a difference between the respective control errors in the feedback control systems and the control error in another feedback control system.

13. The motor control apparatus according to any one of claims 1 to 12, wherein a characteristic equation with respect to an equation of state of the model control system has a multiple root.