JP2009163590A - Lost motion cancellation control apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve the positioning accuracy of a load while considering the influence of backlash in a mechanism for transmitting the power of a motor to the load through a speed reducer. <P>SOLUTION: The torque of the motor 3 is transmitted to a table 1 as a load through the speed reducer 4 and a ball screw driving mechanism 2 to move the table 1. A moving position of the table 1 is feedback controlled by a feedback control device 10. A lost motion cancellation control apparatus 100 determines whether or not a motor rotation direction is reversed when a set time Td elapses from a current time based on track data R and further determines whether a motor speed is reduced to a determination value or less based on a motor speed command V<SB>MO</SB>. When the reversal of the motor rotation direction is determined after the set time Td and the motor speed is reduced to the determination value or less, a noise signal N such as a sin signal is applied to the motor speed command V<SB>MO</SB>. Thus, by applying the noise signal N to the command of a feedback system, lost motion can be canceled. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a lost motion elimination control device, which is devised so that accurate positioning can be performed by eliminating the influence of backlash in the positioning control device.

  In a positioning machine such as a machine tool, a driving force of an electric motor is transmitted to a load to be driven by a reduction gear such as a gear to move the load. In this case, the position of the load is detected, and the drive of the motor is feedback controlled so that the position of the load matches the command position.

FIG. 16 conceptually shows a control system for controlling the position of the table of the machine tool.
As shown in FIG. 16, a table 1 as a load is fixed to a ball nut 2a of a ball screw driving mechanism 2, and a ball screw shaft 2b is screwed to the ball nut 2a. The rotational force of the motor 3 is transmitted to the ball screw shaft 2b via the speed reducer 4.
Therefore, when the motor 3 is rotationally driven, this rotational force is transmitted to the ball screw shaft 2b via the speed reducer 4, and this rotational force is converted into a linear motion force by the ball screw drive mechanism 2, and the table 1 reciprocates.

The position of the table (load) 2 is detected by a load position detection sensor (not shown), and a load position signal θ _L indicating the load position is output. The rotation speed of the motor 3 is detected by a motor rotation speed detection sensor (not shown), and a motor detection speed signal _VMD indicating the motor rotation speed is output.

The feedback control device 10 includes a position control unit 11, a speed control unit 12, and a current control unit 13.
The position control unit 11 obtains a deviation between the position command θ _O sent from the NC device 20 and the load position signal θ _L and multiplies this deviation by a position loop gain to output a motor speed command V _MO .
Speed control unit 12 calculates a deviation between the motor speed command V _MO and the motor detection speed signal V _MD, and outputs the torque command τ the deviation by PI such calculation (proportional integral calculation).
The current control unit 13 supplies a current having a value corresponding to the torque command τ to the motor 3. In this case, although not shown, a current loop control system that performs feedback control so as to obtain an optimum current value is formed.

  In this way, in the case of gear driving in which the driving force of the motor 3 is transmitted to the load 1 by the speed reducer 4, the tooth surfaces are simultaneously on both sides between the teeth of one gear meshing with the teeth of the other gear. It is comprised so that it may not contact. This gap between teeth is called backlash.

Here, the relationship between the gear connected to the motor shaft of the motor 3 and the gear connected to the load side will be described with reference to FIG. In FIG. 17, only a part of the teeth provided on the gear is shown.
The gear connected to the motor shaft will be described as “motor side gear G _M ”, and the gear connected to the load side will be described as “load side gear G _L ”.

17 (a) is contacted tooth surface of the motor side gear G _M and the tooth surfaces of the load side gear G _L is the load side gear G _L is left rotated by the motor side gear G _M rotates clockwise It shows the state.
FIG. 17 (b), the tooth surface of the motor side gear G _M and the tooth surface of the load side gear G _L is a non-contact, the motor side gear G _M is inverted to counterclockwise rotation of right rotation, the load side gear G _L Indicates a stationary state.
FIG. 17 (c) contacts the tooth surface of the tooth surface load side gear G _L of the motor side gear G _M which began to left rotation, the load side gear G _L by the motor side gear G _M is rotated counterclockwise Indicates a state of right rotation.

Relationship between the motor side gear G _M and the load side gear G _L is, when the inverted transitions to the state shown in FIG. 17 (b) from the state of FIG. 17 (a), the or contact surface from the tooth surface to tooth surface At the moment of switching, a stationary section in which the load side gear _GL stops is generated. At this time, the movement position of the table 1, which is a load, generates an error with respect to the target position, and the trajectory tracking accuracy decreases.

Also, at the instant that situation changes to the state shown in FIG. 17 (c) from the state of FIG. 17 (b), the tooth surfaces of the load side gear G _L which tooth surfaces of began to rotate the motor side gear G _M is stationary Touch (collision). Such a sudden collision with the tooth surface may cause instability of control.

FIG. 18 shows the position of the table and the position of the motor in the state of FIGS. That is, the solid line indicates the table position, and the dotted line indicates the motor position. The portions (a), (b), and (c) in FIG. 18 are shown in FIGS. 17 (a), (b), and (c), respectively. It corresponds to the state of.
FIG. 18 also shows that the tracking accuracy of the table position is lower than the motor position.

  Therefore, in order to improve the tracking accuracy, it is necessary to quickly eliminate the idle running state (lost motion) due to backlash.

  Many inventions have been filed to add the backlash clearance to the position command in order to eliminate the idling state (lost motion) due to the backlash. However, in these inventions, the additional timing is set so that the motor speed = 0. It is time.

  In the technique of Patent Document 1 (Japanese Patent Laid-Open No. 10-254548), the lost motion of the mechanical system is absorbed by adding an AC signal to any one of the position command, speed command, and torque command in the feedback control system. Like to do. In the technique of Patent Document 1, the AC signal is continuously added, and the amplitude of the AC signal is made variable depending on the magnitude of the torque command.

Japanese Patent Laid-Open No. 10-254548 JP 59-106010 A JP 2001-195109 A

  As described above, there is a conventional technique in which the backlash clearance is added to the position command when the motor speed is 0. However, depending on the feed speed and acceleration, the motor speed = 0 is not necessarily the moment when the lost motion occurs. Such a conventional technique may not be able to eliminate the lost motion.

  Further, in the technique of Patent Document 1, since an AC signal is continuously output, there is a possibility that the machine is worn out and the positioning accuracy is deteriorated instead.

  An object of the present invention is to provide a lost motion elimination control device capable of preventing the occurrence of lost motion and preventing the occurrence of mechanical wear in view of the above-described prior art.

The configuration of the present invention for solving the above problems is as follows.
In order to control the position of the load while moving the load by transmitting the force generated by the motor to the load that is the object to be moved by a gear mechanism in which a plurality of gears mesh and transmit the force.
A motor speed command is obtained based on a deviation between the load position signal indicating the load position and the position command, and a torque is obtained based on a deviation between the motor detection speed signal obtained by detecting the motor speed and the motor speed command. A lost motion elimination control device applied to a positioning control device including a feedback control device for obtaining a command and controlling a current value supplied to the motor based on the torque command,
The trajectory data, which is data indicating the movement position of the load, is taken in, and the load position after a preset time is pre-read from the current time point, and it is determined whether the rotation direction of the motor is reversed after the preset time. When it is determined that the rotation direction of the motor is reversed, a reading device that sets a motor rotation direction reversal flag;
When the motor speed command is taken in and the absolute value of the motor speed command is less than a predetermined first determination value, a speed reduction flag is set, and the absolute value of the motor speed command is greater than the predetermined first determination value. A speed command detection device that sets a speed increase flag when the value is greater than or equal to a second determination value;
Outputs a noise signal output signal when the reading device sets an inversion flag and the speed command detection device sets a speed decrease flag, and outputs a noise signal when the speed command detection device sets a speed increase flag A noise signal output / stop determination device that stops signal output;
When the noise signal output / stop determination device outputs a noise signal output signal, a noise signal is output, and this noise signal is added to either the position command or the motor speed command or the torque command, A noise signal generator that stops the output of the noise signal when the noise signal output / stop determination device stops outputting the noise signal output signal; and
It is provided with.

In this case, the lost motion elimination control device.
A speed / acceleration creating means for obtaining a load speed signal sθ _L that is the speed of the load and for obtaining a load acceleration signal s ² θ _L that is the acceleration of the load;
The noise signal generator is
When the load moment of inertia is J _L , the resistance between the load and the sliding part is C _L , and the external force due to Coulomb friction is F,
^{_{| J L · s 2 θ L}} + C L · sθ L | <F
If it becomes, the amplitude of the noise signal N is set to a preset amplitude value,
^{_{| J L · s 2 θ L}} + C L · sθ L |> F
In this case, the amplitude of the noise signal N may be made smaller than a preset amplitude value set in advance.

The configuration of the present invention is as follows.
In order to control the position of the load while moving the load by transmitting the force generated by the motor to the load that is the object to be moved by a gear mechanism in which a plurality of gears mesh and transmit the force.
A motor speed command is obtained based on a deviation between the load position signal indicating the load position and the position command, and a torque is obtained based on a deviation between the motor detection speed signal obtained by detecting the motor speed and the motor speed command. A lost motion elimination control device applied to a positioning control device including a feedback control device for obtaining a command and controlling a current value supplied to the motor based on the torque command,
The position command and the load position signal are captured, the position command is differentiated to obtain a motor speed signal, the motor speed signal is positive, and a value obtained by subtracting the load position signal from the position command is a positive determination value set in advance. Noise signal output signal is output when the motor speed signal is negative and the value obtained by subtracting the position command from the load position signal is greater than a preset positive determination value. Stops outputting the noise signal output signal when a predetermined time elapses from when the signal is output or when the motor speed signal exceeds the preset threshold speed after the noise signal output signal is output. A noise signal output / stop determination device,
When the noise signal output / stop determination device outputs a noise signal output signal, a noise signal is output, and this noise signal is added to either the position command or the motor speed command or the torque command, A noise signal generator that stops the output of the noise signal when the noise signal output / stop determination device stops outputting the noise signal output signal; and
It is provided with.

in this case,
The motor may include a sensor that detects a motor rotation position, and a sensor signal output from the sensor may be used instead of the position command.
And a speed / acceleration creating means for obtaining a load speed signal sθ _L that is the speed of the load and for obtaining a load acceleration signal s ² θ _L that is the acceleration of the load,
The noise signal generator is
When the load moment of inertia is J _L , the resistance between the load and the sliding part is C _L , and the external force due to Coulomb friction is F,
^{_{| J L · s 2 θ L}} + C L · sθ L | <F
If it becomes, the amplitude of the noise signal N is set to a preset amplitude value,
^{_{| J L · s 2 θ L}} + C L · sθ L |> F
In this case, the amplitude of the noise signal N may be made smaller than a preset amplitude value set in advance.

The configuration of the present invention is as follows.
In order to control the position of the load while moving the load by transmitting the force generated by the motor to the load that is the object to be moved by a gear mechanism in which a plurality of gears mesh and transmit the force.
A motor speed command is obtained based on a deviation between the load position signal indicating the load position and the position command, and a torque is obtained based on a deviation between the motor detection speed signal obtained by detecting the motor speed and the motor speed command. A lost motion elimination control device applied to a positioning control device including a feedback control device for obtaining a command and controlling a current value supplied to the motor based on the torque command,
A differentiator that differentiates the load position signal and outputs a load speed signal;
The motor speed command and the load speed signal are taken in, the motor rotation direction when the motor is rotating / stopped and rotating is detected from the taken motor speed command, and the load is moved from the taken load speed signal.・ Detects the moving direction of the load when stopped and moving, and when the motor rotating direction and load moving direction are in reverse phase, or when the load is stopped and the motor is rotating When the noise signal output signal is output and the predetermined time has elapsed from the time when the noise signal output signal is output, or after the time when the noise signal output signal is output, the motor speed command exceeds the preset threshold speed. A noise signal output / stop determination device that stops the output of the noise signal output signal when it becomes large,
When the noise signal output / stop determination device outputs a noise signal output signal, a noise signal is output, and this noise signal is added to either the position command or the motor speed command or the torque command, A noise signal generator that stops the output of the noise signal when the noise signal output / stop determination device stops outputting the noise signal output signal; and
It is provided with.

in this case,
A sensor for detecting the load speed of the load may be provided instead of the differentiator, and a sensor signal output from the sensor may be used instead of the load speed signal.
And an acceleration creating means for obtaining a load acceleration signal s ² θ _L which is the acceleration of the load,
The noise signal generator is
When the load moment of inertia is J _L , the resistance between the load and the sliding part is C _L , and the external force due to Coulomb friction is F,
_{^{| J L · s 2 θ L}} + C L · sθ L | <F
If it becomes, the amplitude of the noise signal N is set to a preset amplitude value,
_{^{| J L · s 2 θ L}} + C L · sθ L |> F
In this case, the amplitude of the noise signal N may be made smaller than a preset amplitude value set in advance.

The configuration of the present invention is as follows.
The noise signal generator is characterized in that when outputting a noise signal, the amplitude of the noise signal is gradually increased to a set amplitude, and when stopping the noise signal, the amplitude of the noise signal is gradually decreased and then stopped. To do.
The noise signal output from the noise signal generator is a repetitive signal or a pulse signal.

The configuration of the present invention is as follows.
In order to control the position of the load while moving the load by transmitting the force generated by the motor to the load that is the object to be moved by a gear mechanism in which a plurality of gears mesh and transmit the force.
A motor speed command is obtained based on a deviation between the load position signal indicating the load position and the position command, and a torque is obtained based on a deviation between the motor detection speed signal obtained by detecting the motor speed and the motor speed command. A lost motion elimination control device applied to a positioning control device including a feedback control device for obtaining a command and controlling a current value supplied to the motor based on the torque command,
The position command and the load position signal are captured, the position command is differentiated to obtain a motor speed signal, the motor speed signal is positive, and a value obtained by subtracting the load position signal from the position command is a positive determination value set in advance. Noise signal output signal is output when the motor speed signal is negative and the value obtained by subtracting the position command from the load position signal is greater than a preset positive determination value. Stops outputting the noise signal output signal when a predetermined time elapses from when the signal is output or when the motor speed signal exceeds the preset threshold speed after the noise signal output signal is output. A noise signal output / stop determination device,
The motor speed command is taken in, the motor rotation direction is determined based on the motor speed command, the noise signal output / stop determination device outputs a noise signal output signal, and the motor rotation direction is a positive direction. When the determination is made, the amplitude value at the time of output is positive, the amplitude value gradually decreases with the passage of time thereafter, and finally a sawtooth noise signal having an amplitude value of zero is output. When the noise signal output / stop determination device outputs a noise signal output signal in addition to either the position command, the motor speed command or the torque command, and determines that the rotation direction of the motor is negative. A sawtooth noise signal is output in which the amplitude value at the time of output is negative, the amplitude value gradually decreases with time, and finally the amplitude value becomes zero, and this noise signal is output to the position command or In addition to any one of the motor speed or the torque command, when the noise signal output-stop determination device stops the output of the noise signal output signal, and a noise signal generator for stopping the output of the noise signal,
It is provided with.

  In this case, the noise signal generation device may continuously output the sawtooth noise signal when the motor speed command is larger than the load speed signal.

The configuration of the present invention is as follows.
In order to control the position of the load while moving the load by transmitting the force generated by the motor to the load that is the object to be moved by a gear mechanism in which a plurality of gears mesh and transmit the force.
A motor speed command is obtained based on a deviation between the load position signal indicating the load position and the position command, and a torque is obtained based on a deviation between the motor detection speed signal obtained by detecting the motor speed and the motor speed command. A lost motion elimination control device applied to a positioning control device including a feedback control device for obtaining a command and controlling a current value supplied to the motor based on the torque command,
A differentiator that differentiates the load position signal and outputs a load speed signal;
The motor speed command and the load speed signal are taken in, the motor rotation direction when the motor is rotating / stopped and rotating is detected from the taken motor speed command, and the load is moved from the taken load speed signal.・ Detects the moving direction of the load when stopped and moving, and when the motor rotating direction and load moving direction are in reverse phase, or when the load is stopped and the motor is rotating When the noise signal output signal is output and the predetermined time has elapsed from the time when the noise signal output signal is output, or after the time when the noise signal output signal is output, the motor speed command exceeds the preset threshold speed. A noise signal output / stop determination device that stops the output of the noise signal output signal when it becomes large,
The motor speed command is taken in, the motor rotation direction is determined based on the motor speed command, the noise signal output / stop determination device outputs a noise signal output signal, and the motor rotation direction is a positive direction. When the determination is made, the amplitude value at the time of output is positive, the amplitude value gradually decreases with the passage of time thereafter, and finally a sawtooth noise signal having an amplitude value of zero is output. When the noise signal output / stop determination device outputs a noise signal output signal in addition to either the position command, the motor speed command or the torque command, and determines that the rotation direction of the motor is negative. A sawtooth noise signal is output in which the amplitude value at the time of output is negative, the amplitude value gradually decreases with time, and finally the amplitude value becomes zero, and this noise signal is output to the position command or In addition to any one of the motor speed or the torque command, when the noise signal output-stop determination device stops the output of the noise signal output signal, and a noise signal generator for stopping the output of the noise signal,
It is provided with.

  In this case, the noise signal generation device may continuously output the sawtooth noise signal when the motor speed command is larger than the load speed signal.

According to the present invention, the occurrence of backlash is determined from the motor speed and motor rotation direction, from the position of the motor and load, or from the speed status of the motor and load. Sometimes a noise signal is added to the position command, speed command or torque command in the feedback control device.
For this reason, it is possible to suppress hysteresis between the input and output shafts such as a dead zone and lost motion due to backlash of a gear machine such as a reduction gear.

  Hereinafter, the best mode for carrying out the present invention will be described in detail based on examples.

FIG. 1 shows a positioning control device including a lost motion elimination control device according to Embodiment 1 of the present invention. This positioning control device includes a feedback control device 10, an NC device 20, and a lost motion elimination control device 100.
The feedback control device 10 and the NC device 20 are the same as those of the prior art. The table (load) 1, the ball screw drive mechanism 2, the motor 3, and the speed reducer 4 are the same as those of the prior art.

The lost motion elimination control device 100 according to the first embodiment uses a noise signal N such as a sine wave signal as a position command θo and a motor speed command when the motor speed is low and the motor rotation direction is reversed. This is superimposed on either V _M or torque command τ.

  The lost motion elimination control device 100 includes a reading device 101, a speed command detection device 102, a noise signal output / stop determination device 103, and a noise signal generation device 104.

  Here, the operation of the lost motion elimination control apparatus 100 will be described with reference to FIGS. 1 and 2.

The reading device 101 takes in the trajectory data R from the NC device 20. The trajectory data R is data indicating the moving position of the load (table 1) whose position changes with the passage of time from the machining start time.
Further, the reading device 101 refers to the trajectory data R and pre-reads the load position after a pre-read setting time T _d [second] determined in advance from the current time point.
Then, if it is determined that the motor rotation direction is reversed after the prefetch setting time T _d [second] from the current time point based on the load position after the prefetch setting time T _d [second] as seen from the current time point, the motor rotation direction is reversed. The flag F1 is set (output).
When it is determined that the motor rotation direction is not reversed after the prefetch setting time T _d [seconds] from the current time point, the motor rotation direction reversal flag F1 is not set (not output).

Speed command detector 102 accepts the specified motor speed V _MO from the feedback control unit 10, the absolute value of the specified motor speed V _MO is, when it becomes a less than a determination value epsilon _s previously set speed decrease flag F2 Is set (output).
Further, when the absolute value of the motor speed command V _MO becomes equal to or greater than a preset second determination value ε _e , the speed increase flag F3 is set (output).
The second determination value ε _e is larger than the first determination value ε _s .

The noise signal output / stop determination device 103 outputs a noise signal output signal ON when the motor rotation direction reversal flag F1 is set and the speed reduction flag F2 is set.
On the other hand, when the flags F1 and F2 are not standing together or when the speed increase flag F3 is set after the speed decrease flag F2 is set, the output of the noise signal output signal ON is stopped.

The noise signal generator 104 generates a noise signal N. When the noise signal output signal ON is sent from the noise signal output / stop determination device 103, the noise signal N is output. This noise signal N is added to the motor speed command V _MO via the adder 14 provided in the feedback control device 10.
On the other hand, when the output of the noise signal output signal ON from the noise signal output / stop determination device 103 is stopped, the noise signal generator 104 stops the output of the noise signal N.
As the noise signal N, for example, a repetitive signal such as a sine wave signal or a pulse signal can be used.

The lost motion elimination control device 100 includes a limited period before and after this time, including a time point when the motor speed command _VMO becomes smaller (the rotational speed of the motor 3 becomes smaller) and the motor rotation direction is reversed. The noise signal N is added to the motor speed command _VMO .

As a result of the noise signal N being added to the motor speed command V _MO in this way, the motor 3 performs forward / reverse operation very minutely by the noise signal N. As a result, a dead zone due to backlash, lost motion, etc. Hysteresis between the input and output shafts can be suppressed.

In addition, the noise signal N is locally applied only in the vicinity where the rotation direction of the motor 3 is reversed (motor speed ≈ 0) to prevent deterioration of the trajectory tracking accuracy and to hardware aspects such as equipment wear and motor heat generation. The adverse effects of can be minimized.
That is, since the noise signal N may adversely affect the original positioning control, the noise signal N is not continuously applied for a long time, and is used only in a situation where backlash is a problem. In addition to preventing deterioration of the track following accuracy, adverse effects on hardware such as equipment wear and motor heat generation can be minimized.

In the example of FIG. 1, the noise signal N is superimposed on the motor speed command V _MO , but the noise signal N may be superimposed on the position command θ _O and the torque command τ.

Furthermore, when the noise signal N is output from the noise signal generator 104 and when the noise signal N that has been output is stopped, the noise signal N may be tapered.
That is, when the noise signal N is output, the amplitude of the noise signal N is gradually increased to the rated amplitude, and when the noise signal N is stopped, the noise signal amplitude is gradually decreased from the rated amplitude and then stopped. To do.
In this case, the taper is given as a function of operating speed, temperature, time, and the like.
Since the noise signal N is tapered in this way, the impact on the motor 3 that occurs when the noise signal N is output / stopped can be suppressed, so that deterioration in positioning accuracy can be prevented.

FIG. 3 shows a positioning control device including a lost motion elimination control device according to Embodiment 2 of the present invention. This positioning control device includes a feedback control device 10, an NC device 20, and a lost motion elimination control device 200.
The feedback control device 10 and the NC device 20 are the same as those of the prior art. The table (load) 1, the ball screw drive mechanism 2, the motor 3, and the speed reducer 4 are the same as those of the prior art.

The lost motion elimination control apparatus 200 according to the second embodiment monitors the position status of the motor and the load, and when it is determined that both are operating at a low speed and performing a motion specific to the lost motion, a sine wave signal, etc. The noise signal N is superimposed on any one of the position command θo, the motor speed command V _M , and the torque command τ.

  The lost motion elimination control device 200 includes a noise signal output / stop determination device 203 and a noise signal generation device 204.

Noise signal output, stop determination unit 203 fetches an instruction to the position of the motor 3 and (indicating the position of the motor 3) the position command .theta.o, the load position signal theta _L indicating the position of the load.
The noise signal output / stop determination device 203 differentiates the position command θo to obtain a motor speed signal sθo, and determines whether the motor speed signal sθo is positive or negative.
The noise signal output / stop determination device 203 stores a determination value ε that is a positive value set in advance. The determination value ε is a value corresponding to the difference between the motor position and the load position at the time of high-speed feeding without lost motion, for example, the value of θo−θ _L at the time of high-speed feeding without lost motion.

The noise signal output / stop determination device 203
(1) When the motor speed signal sθo is positive, that is, when the motor 3 is rotating forward,
θo−θ _L > ε
If
(2) When the motor speed signal sθo is negative, that is, when the motor 3 is driven in reverse,
θ _L −θo> ε
If
It is determined that a lost motion has occurred.

That is, in the state of (1) above, the motor position precedes the load position (the load follows the motor with a delay) in the state where the motor is normally driven, and both positions Since the difference is larger than the set value ε, it can be determined that the lost motion has occurred.
In the state (2), the load position precedes the motor position (the motor follows with a delay with respect to the load) in a state where the motor is driven reversely, and the difference between the two positions is Since it is larger than the set value ε, it can be determined that the lost motion has occurred.

  The noise signal output / stop determination device 203 outputs the noise signal output signal ON when it is determined that the lost motion is generated by the above-described lost motion determination method, and when it is determined that the lost motion is not generated. The noise signal output signal ON is not output.

  The noise signal output / stop determination device 203 stops the output of the noise signal output signal or outputs the noise signal output signal ON when a predetermined time elapses from the time when the noise signal output signal ON is output. Thereafter, when the motor speed signal sθo becomes larger than a preset threshold speed, the output of the noise signal output signal ON is stopped.

The noise signal generator 204 generates a noise signal N. When the noise signal output signal ON is sent from the noise signal output / stop determination device 203, the noise signal N is output. This noise signal N is added to the motor speed command V _MO via the adder 14 provided in the feedback control device 10.
On the other hand, the noise signal generation device 204 stops the output of the noise signal N when the output of the noise signal output signal ON from the noise signal output / stop determination device 203 is stopped.
As the noise signal N, for example, a repetitive signal such as a sine wave signal or a pulse signal can be used.

The lost motion elimination control device 200 directly monitors the position status of the motor and the load, and when it is determined that the movement of the motor and the load is peculiar to the lost motion, the noise signal N is transmitted to the motor speed command. It has been added to the V _M.

As a result of the noise signal N being added to the motor speed command V _MO in this way, the motor 3 performs forward / reverse operation very minutely by the noise signal N. As a result, a dead zone due to backlash, lost motion, etc. Hysteresis between the input and output shafts can be suppressed.

In addition, only when it is determined that the lost motion is actually occurring, the noise signal N is applied to prevent the deterioration of the trajectory tracking accuracy, and the adverse effects on hardware such as equipment wear and motor heat generation are minimized. Can be suppressed.
That is, since the noise signal N may adversely affect the original positioning control, the noise signal N is not continuously applied for a long time, and is used only in a situation where backlash is a problem. In addition to preventing deterioration of the track following accuracy, adverse effects on hardware such as equipment wear and motor heat generation can be minimized.

  Furthermore, in the conventional PID control technology, the lost motion begins to disappear only after the feedback of the table position is effective. In this embodiment, since the occurrence of the lost motion is directly detected, the conventional PID control technology is more effective than the conventional PID control technology. It becomes possible to eliminate lost motion as soon as possible.

In addition, since the generation timing of the lost motion differs depending on the feed speed, it may not be possible to compensate accurately and effectively just by monitoring the motor speed command as in the first embodiment and following a uniform rule.
In this embodiment, since the noise signal N for eliminating the lost motion is output by directly monitoring the relationship between the motor and the load operation, the lost motion can be compensated appropriately.

  In the above example, the position command θo is used as a signal indicating the position of the motor. However, an encoder or the like that detects the motor position is attached to the motor 3, and the motor position signal output from the encoder is replaced with the position command θo. It can also be used.

In the example of FIG. 3, the noise signal N is superimposed on the motor speed command V _MO , but the noise signal N may be superimposed on the position command θ _O and the torque command τ.

Furthermore, the noise signal N may be tapered when the noise signal N is output from the noise signal generator 204 and when the output noise signal N is stopped.
That is, when the noise signal N is output, the amplitude of the noise signal N is gradually increased to the rated amplitude, and when the noise signal N is stopped, the noise signal amplitude is gradually decreased from the rated amplitude and then stopped. To do.
In this case, the taper is given as a function of operating speed, temperature, time, and the like.
Since the noise signal N is tapered in this way, the impact on the motor 3 that occurs when the noise signal N is output / stopped can be suppressed, so that deterioration in positioning accuracy can be prevented.

FIG. 4 shows a positioning control device including a lost motion elimination control device according to Embodiment 3 of the present invention. This positioning control device includes a feedback control device 10, an NC device 20, and a lost motion elimination control device 300.
The feedback control device 10 and the NC device 20 are the same as those of the prior art. The table (load) 1, the ball screw drive mechanism 2, the motor 3, and the speed reducer 4 are the same as those of the prior art.

The lost motion elimination control apparatus 300 according to the third embodiment monitors the speed status of the motor and the load, determines whether the movement direction of both motors is in-phase or out-of-phase, and detects noise such as a sine wave signal when the in-phase movement is detected. The signal N is superimposed on any one of the position command θo, the motor speed command V _M , and the torque command τ.

  The lost motion elimination control device 300 includes a noise signal output / stop determination device 303, a noise signal generation device 304, and a differentiator 305.

Differentiator 305 differentiates the load position signal theta _L, and outputs a load speed signal S.theta _L indicating the speed of the load.

The noise signal output / stop determination device 303 takes in a motor speed command V _MO that indicates the speed of the motor 3 (indicating the speed of the motor 3) and a load speed signal sθ _L that indicates the speed of the load.

The noise signal output / stop determination device 303 has the determination criteria shown in Table 1 below. In Table 1, α _M is a positive constant for determining the rotation direction of the motor, and α _L is a positive constant for determining the moving direction of the load.
In Table 1,
When V _MO > α _M , it is determined that the motor 3 is rotating forward,
When V _MO <−α _M , it is determined that the motor 3 is rotating in reverse,
When | V _MO | <α _M , it is determined that the motor 3 is stopped,
When Sθ _L > α _L , it is determined that the load (table 1) is moving in the positive direction,
When Sθ _L <−α _L , it is determined that the load (table 1) is moving in the negative direction,
When | Sθ _L | <α _L , it is determined that the load (table 1) is stopped.

The noise signal output / stop determination device 303 makes the following determination according to each mode, and outputs / stops the noise signal output signal ON according to each determination.
(A) In modes 1 and 4, it is determined that the motor rotation direction and the load moving direction are in phase. In this case, it is determined that no lost motion has occurred, and the noise signal output signal ON is not output.
(B) In modes 5 and 6, it is determined that the load is moving while the motor 3 is stopped. In this case, it is determined that no lost motion has occurred, and the noise signal output signal is ON. Is not output.
(C) In modes 2 and 3, it is determined that the motor rotation direction and the load movement direction are in reverse phase, and in this case, it is determined that a lost motion has occurred, and a noise signal output signal ON is output. .
(D) In modes 7 and 8, it is determined that the load is stopped while the motor 3 is rotating. In this case, it is determined that a lost motion has occurred, and the noise signal output signal is ON. Is output.

The noise signal output / stop determination device 303 stops the output of the noise signal output signal or outputs the noise signal output signal ON when a predetermined time has elapsed from the time of outputting the noise signal output signal ON. Thereafter, when the motor speed command _VMO increases beyond a preset threshold speed, the output of the noise signal output signal ON is stopped.

The noise signal generator 304 generates a noise signal N. When the noise signal output signal ON is sent from the noise signal output / stop determination device 303, the noise signal N is output. This noise signal N is added to the motor speed command V _MO via the adder 14 provided in the feedback control device 10.
On the other hand, when the output of the noise signal output signal ON from the noise signal output / stop determination device 303 is stopped, the noise signal generator 304 stops the output of the noise signal N.
As the noise signal N, for example, a repetitive signal such as a sine wave signal or a pulse signal can be used.

The lost motion elimination control apparatus 300 directly monitors the speed status of the motor and the load, and when it is determined that the status determined from the speed of the motor and the load is a status specific to the lost motion, the noise signal N a is added to the motor speed V _M.

As a result of the noise signal N being added to the motor speed command V _MO in this way, the motor 3 performs forward / reverse operation very minutely by the noise signal N. As a result, a dead zone due to backlash, lost motion, etc. Hysteresis between the input and output shafts can be suppressed.

In addition, only when it is determined that the lost motion is actually occurring, the noise signal N is applied to prevent the deterioration of the trajectory tracking accuracy, and the adverse effects on hardware such as equipment wear and motor heat generation are minimized. Can be suppressed.
That is, since the noise signal N may adversely affect the original positioning control, the noise signal N is not continuously applied for a long time, and is used only in a situation where backlash is a problem. In addition to preventing deterioration of the track following accuracy, adverse effects on hardware such as equipment wear and motor heat generation can be minimized.

In addition, since the generation timing of the lost motion differs depending on the feed speed, it may not be possible to compensate accurately and effectively just by monitoring the motor speed command as in the first embodiment and following a uniform rule.
In this embodiment, since the noise signal N for eliminating the lost motion is output by directly monitoring the relationship between the motor and the load speed, the lost motion can be compensated appropriately.

In the above example, a load speed signal sθ _L obtained by first-order differentiation of the load position signal θ _L is used as a signal indicating the motor speed. However, a sensor (for example, a resolver) for detecting the load speed is provided in the load. the sensor signal output from the sensor can be used instead of the load speed signal S.theta _L.

In the example of FIG. 4, the noise signal N is superimposed on the motor speed command V _MO , but the noise signal N may be superimposed on the position command θ _O and the torque command τ.

Further, when the noise signal N is output from the noise signal generator 304 and when the noise signal N that has been output is stopped, the noise signal N may be tapered.
That is, when the noise signal N is output, the amplitude of the noise signal N is gradually increased to the rated amplitude, and when the noise signal N is stopped, the noise signal amplitude is gradually decreased from the rated amplitude and then stopped. To do.
In this case, the taper is given as a function of operating speed, temperature, time, and the like.
Since the noise signal N is tapered in this way, the impact on the motor 3 that occurs when the noise signal N is output / stopped can be suppressed, so that deterioration in positioning accuracy can be prevented.

FIG. 5 shows a positioning device including a lost motion elimination control device 100a according to a fourth embodiment of the present invention. This lost motion elimination control device 100a is an improvement of the lost motion elimination control device 100 of the first embodiment shown in FIG.
Therefore, only a different part from Example 1 is demonstrated, the same code | symbol is attached | subjected to the part same as Example 1, and the overlapping description is abbreviate | omitted.

  In the lost motion elimination control device 100a of the fourth embodiment, the occurrence state of the lost motion is determined from the elements of load inertia, coulomb friction, and viscous resistance, and the amplitude of the noise signal N generated from the noise signal generator 104 is adjusted. It is something that can be done.

The lost motion elimination control device 100a has two differentiators 105 and 106. The differentiator 105 differentiates the load position signal θ _L and outputs a load speed signal sθ _L indicating the load speed, and the differentiator 106 differentiates the load speed signal sθ _L to load an acceleration signal indicating the load acceleration. s ² θ _L is output.

The load speed signal sθ _L and the load acceleration signal s ² θ _L are input to the noise signal generator 104. The timing at which the noise signal generator 104 outputs the noise signal N is the same as that in the first embodiment, but in the fourth embodiment, the amplitude of the noise signal N is adjusted.

Here, the principle that is the basis for adjusting the amplitude of the noise signal N will be described.
The lost motion is a state from the meshing state of the motor and the load teeth until the motor reversely rotates and meshes with the opposite tooth, and the point is how quickly this state is finished.

Here, attention is paid to the relationship between the motion of the load and the friction.
If the friction is greater than the inertial force of the load, the load will remain stationary in the lost motion state, and the lost motion state will continue unless the motor moves and the teeth mesh. This state, for example, in FIG. 17 (b), the load side gear G _L is stationary by frictional force, the motor side gear G _M is been inverted left rotation right rotation corresponds to a state that is rotated to the left (this The state is referred to as “state a”).
In this way, when the Coulomb friction is larger than the momentum, the load does not move unless the driving force is applied from the motor.Therefore, the tooth surface of the reducer is always in contact with the backlash clearance. Only lost motion occurs.
In this case, the generation period of the lost motion is long.

On the other hand, when the inertial force of the load exceeds the friction, the load continues to move with inertia and meshes with the teeth of the motor. This state, for example, in FIG. 17 (b), the continued counterclockwise rotation load side gear G _L is the inertia force, the motor side gear G _M corresponds to the state in which the left rotates been inverted left rotation right rotation (This state is referred to as “state b”).
When the momentum is large in this way, the load moves with its own inertia, so the tooth surface of the reduction gear is macroscopically floating. Therefore, the lost motion is smaller than the backlash clearance.
In this case, the lost motion generation period is short.

As described above, since the time at which the lost motion ends varies depending on the relationship between the inertial force of the load and the magnitude of the frictional force, compensation that takes these into consideration is necessary.
Therefore, when the frictional force is larger than the inertial force, the noise signal N is given large, and when the frictional force is smaller than the inertial force, the noise signal N is given small so that compensation can be performed without excess or deficiency. .

An example of the equation of motion on the load side when the motor-side teeth and the load-side teeth are not meshed is as follows. Note that J _L is a load inertia moment, C _L is a resistance such as damping between the load and a sliding portion, and F is an external force such as coulomb friction. In both cases, the nominal value is obtained and the value is determined in advance.
J _L · s ² θ _L + C _L · sθ _L = F

  In view of the above knowledge, the noise signal generator 104 adjusts the amplitude of the output noise signal N as follows.

^{_{| J L · s 2 θ L}} + C L · sθ L | <F
In this case, the frictional force overcomes the momentum, that is, the “state a”. Therefore, at this time, the amplitude of the noise signal N is increased (to a preset amplitude value set in advance).

^{_{| J L · s 2 θ L}} + C L · sθ L |> F
In this case, since the load is in a state where it continues to move due to inertia, that is, in the “state b”, the teeth on the motor side and the teeth on the load side mesh faster than in the “state a”. Therefore, at this time, the amplitude of the noise signal N is suppressed (smaller than the set amplitude value).

In order to suppress the amplitude of the noise signal N in the “state b”, for example, the noise signal generator 104 includes the characteristics shown in FIG. 6 (the horizontal axis is the amplitude A ₀ of the noise N and the horizontal axis is Γ ( ^{_{= | J L · s 2 θ}} L + C L · sθ L |. in) are stored 6, the noise amplitude when the gamma = F is set to a _01.
And
When Γ <F, A ₀ = A ₀₁ and
When Γ> F, A ₀ = (FA ₀₁ ) / Γ.

  In the above example, the amplitude of the noise signal N is decreased in inverse proportion when Γ> F, but may have a linear characteristic with a downward slope.

In Example 4, since the magnitude of the lost motion differs depending on the relationship between the momentum and the Coulomb friction, this is calculated and the amplitude of the noise signal is changed according to the magnitude of the lost motion.
In the prior art, the amplitude of the correction signal could not be sufficiently increased because it may adversely affect the trajectory accuracy. However, in this embodiment, the noise signal N having a sufficient amplitude can be provided when necessary. , Lost motion can be resolved quickly.

In the above example, are used the load acceleration signal s ² theta _L of the load position signal theta _L obtained by differentiating, may be used acceleration signals outputted acceleration of the load from the sensor capable of detecting .

Furthermore, when the noise signal N is output from the noise signal generator 104 and when the noise signal N that has been output is stopped, the noise signal N may be tapered.
That is, when the noise signal N is output, the amplitude of the noise signal N is gradually increased to the set amplitude, and when the noise signal N is stopped, the amplitude of the noise signal is gradually decreased and then stopped.
In this case, the taper is given as a function of operating speed, temperature, time, and the like.
Since the noise signal N is tapered in this way, the impact on the motor 3 that occurs when the noise signal N is output / stopped can be suppressed, so that deterioration in positioning accuracy can be prevented.

FIG. 7 shows a positioning device including a lost motion elimination control device 200a according to a fifth embodiment of the present invention. This lost motion elimination control device 200a is an improvement over the lost motion elimination control device 200 of the second embodiment shown in FIG.
Therefore, only a different part from Example 2 is demonstrated, the same code | symbol is attached | subjected to the part same as Example 2, and the overlapping description is abbreviate | omitted.

  In the lost motion elimination control device 200a of the fifth embodiment, as in the fourth embodiment, the occurrence state of the lost motion is determined from the load inertia moment, coulomb friction, and viscous resistance, and the noise signal generation device 204 generates the lost motion. The amplitude of the noise signal N can be adjusted.

The lost motion elimination control device 200a has two differentiators 205 and 206. The differentiator 205 differentiates the load position signal θ _L and outputs a load speed signal sθ _L indicating the load speed, and the differentiator 206 differentiates the load speed signal sθ _L to load an acceleration signal indicating the load acceleration. s ² θ _L is output.

The load speed signal sθ _L and the load acceleration signal s ² θ _L are input to the noise signal generator 204. The timing at which the noise signal generator 204 outputs the noise signal N is the same as in the second embodiment, but in the fifth embodiment, the amplitude of the noise signal N is adjusted.

  Similar to the noise signal generator 104 of the fourth embodiment, the noise signal generator 204 of the present embodiment adjusts the amplitude of the noise signal N to be output as follows.

^{_{| J L · s 2 θ L}} + C L · sθ L | <F
In this case, the amplitude of the noise signal N is increased because the frictional force has overcome the momentum.

^{_{| J L · s 2 θ L}} + C L · sθ L |> F
In this case, since the load continues to move due to inertia, the amplitude of the noise signal N is suppressed. The method of suppression is the same as that in the fourth embodiment.

In the above example, are used the load acceleration signal s ² theta _L of the load position signal theta _L obtained by differentiating, may be used acceleration signals outputted acceleration of the load from the sensor capable of detecting .

Furthermore, the noise signal N may be tapered when the noise signal N is output from the noise signal generator 204 and when the output noise signal N is stopped.
That is, when the noise signal N is output, the amplitude of the noise signal N is gradually increased to the set amplitude, and when the noise signal N is stopped, the noise signal amplitude is gradually decreased from the set amplitude and then stopped. To do.
In this case, the taper is given as a function of operating speed, temperature, time, and the like.
Since the noise signal N is tapered in this way, the impact on the motor 3 that occurs when the noise signal N is output / stopped can be suppressed, so that deterioration in positioning accuracy can be prevented.

Furthermore, the noise signal N may be tapered when the noise signal N is output from the noise signal generator 204 and when the output noise signal N is stopped.
That is, when the noise signal N is output, the amplitude of the noise signal N is gradually increased to the set amplitude, and when the noise signal N is stopped, the amplitude of the noise signal is gradually decreased and then stopped.
In this case, the taper is given as a function of operating speed, temperature, time, and the like.
Since the noise signal N is tapered in this way, the impact on the motor 3 that occurs when the noise signal N is output / stopped can be suppressed, so that deterioration in positioning accuracy can be prevented.

FIG. 8 shows a positioning device including a lost motion elimination control device 300a according to Embodiment 6 of the present invention. This lost motion elimination control device 300a is an improvement over the lost motion elimination control device 300 of the third embodiment shown in FIG.
Therefore, only a different part from Example 3 is demonstrated, the same code | symbol is attached | subjected to the part same as Example 3, and the overlapping description is abbreviate | omitted.

  In the lost motion elimination control device 300a of the sixth embodiment, as in the fourth embodiment, the occurrence state of the lost motion is determined from the elements of load inertia, coulomb friction, and viscous resistance, and generated from the noise signal generator 304. The amplitude of the noise signal N can be adjusted.

The lost motion elimination control device 300a has a differentiator 306. Differentiator 306 differentiates the load speed signal S.theta _L, and outputs the load acceleration signal s ² theta _L indicating the acceleration of the load.

The load speed signal sθ _L and the load acceleration signal s ² θ _L are input to the noise signal generator 304. The timing at which the noise signal generator 304 outputs the noise signal N is the same as in the third embodiment, but in the sixth embodiment, the amplitude of the noise signal N is adjusted.

  Similar to the noise signal generator 104 of the fourth embodiment, the noise signal generator 304 of the present embodiment adjusts the amplitude of the noise signal N to be output as follows.

^{_{| J L · s 2 θ L}} + C L · sθ L | <F
In this case, the amplitude of the noise signal N is increased because the frictional force has overcome the momentum.

^{_{| J L · s 2 θ L}} + C L · sθ L |> F
In this case, since the load continues to move due to inertia, the amplitude of the noise signal N is suppressed. The method of suppression is the same as that in the fourth embodiment.

In the above example, are used the load acceleration signal s ² theta _L of the load position signal theta _L obtained by differentiating, may be used acceleration signals outputted acceleration of the load from the sensor capable of detecting .

Further, when the noise signal N is output from the noise signal generator 304 and when the noise signal N that has been output is stopped, the noise signal N may be tapered.
That is, when the noise signal N is output, the amplitude of the noise signal N is gradually increased to the set amplitude, and when the noise signal N is stopped, the amplitude of the noise signal is gradually decreased and then stopped.
In this case, the taper is given as a function of operating speed, temperature, time, and the like.
Since the noise signal N is tapered in this way, the impact on the motor 3 that occurs when the noise signal N is output / stopped can be suppressed, so that deterioration in positioning accuracy can be prevented.

FIG. 9 shows a positioning device including a lost motion elimination control device 200b according to Embodiment 7 of the present invention. This lost motion elimination control device 200b is an improvement over the lost motion elimination control device 200 of the second embodiment shown in FIG.
Therefore, only a different part from Example 2 is demonstrated, the same code | symbol is attached | subjected to the part same as Example 2, and the overlapping description is abbreviate | omitted.

In the lost motion elimination control device 200b of the seventh embodiment, the noise signal output signal ON is sent from the noise signal output / stop determination device 203 to the noise signal generation device 204b, and the motor speed command V _MO is sent from the position control unit 11. Will be sent.

The noise signal generator 204b outputs a sawtooth noise signal N _b (see FIGS. 11A and 11B). Timing for outputting the noise signal N _b of the sawtooth is, the noise signal generator 204 in Embodiment 2 is the same as the timing for outputting the noise signal N.

Here, the noise signal generator 204b, a procedure for generating and outputting a noise signal N _b sawtooth will be described with reference to FIG. 10 is a flow chart.

  In step 1, it is determined whether or not the occurrence of lost motion has been detected, that is, whether or not the noise signal output signal ON has been input to the noise signal generator 204b.

When detecting the occurrence of lost motion, i.e., when the noise signal output signal ON is input to the noise signal generator 204b determines at step 2, the direction of rotation of the motor 3, on the basis of the motor speed V _MO .

When the rotation direction of the motor 3 is positive, at step 3, obtaining a noise signal N _b using the following equation.
N _b = No (1-L∫dt)
However, No and L are predetermined constants.

The noise signal N _b obtained by the above equation is subjected to limit processing in step 4 and when the value of the noise signal N _b gradually decreases with time and becomes zero, the value of the noise signal N _b is thereafter obtained. Holds the value to zero so that does not become negative.
Then, in step 5, and it outputs a sawtooth noise N _b as shown in FIG. 11 (a).

When it is determined in step 2 that the rotation direction of the motor 3 is negative, in step 6, the noise signal N _b is obtained using the following equation.
N _b = −No (1−L∫dt)
However, No and L are predetermined constants.

The noise signal N _b obtained by the above equation is subjected to limit processing in step 7 and when the value of the noise signal N _b gradually increases with time and becomes zero, the value of the noise signal N _b is thereafter obtained. Holds the value to zero so that does not become positive.
Then, in step 8, and it outputs a sawtooth noise N _b as shown in FIG. 11 (b).

If it is determined in step 2 that the rotation direction of the motor 3 has become zero (still), the noise signal N _b is set to 0 in step 9, and further, immediately before steps 10 and 11. when the value of the noise signal N _b up is not zero and resets the integrated value, as zero value of the noise signal N _b, finally in step 12, the output noise signal N _b with a value of zero Yes (stops noise signal output).

When it is determined in step 1 that no lost motion has occurred, if the value of the noise signal N _b until just before in steps 13 and 14 is not zero, the integrated value is reset and the value of the noise signal N _b is zero. as at the final step 15, (it stops outputting the noise signals) for outputting a noise signal N _b with a value of zero.

According to this embodiment, by adding the noise signal N _b sawtooth at the moment of lost motion generation, input, such as dead band or lost motion due to the backlash - it is possible to suppress the hysteresis between the output shaft.

Furthermore, the noise signal N _b, the value is the largest at the moment the output has become a amplitude characteristic whose value gradually decreases with followed the time course.
Therefore, the output of the noise signal N _b can be suddenly engage the teeth of the reduction gear. Then, by the value of the noise signal N _b by the tapered portion of the noise signal N _b by monotonically decreasing adapt the teeth, it can attenuate immediately vibration generated by the impact on engagement.

In the example of FIG. 9, the noise signal N _b is superimposed on the motor speed command V _MO , but the noise signal N _b may be superimposed on the position command θ _O and the torque command τ.

Further, the techniques shown in the fourth and fifth embodiments can be added.
That is, the state of occurrence of lost motion is determined from the elements of load inertia, coulomb friction, and viscous resistance, and the relationship between the frictional force and the inertial force is obtained from the following equation of motion.
J _L · s ² θ _L + C _L · sθ _L = F
Then, when the frictional force is greater than the inertia force is applied increases the initial value No of the noise signal N _b, if the frictional force is smaller than the inertial force by giving small initial value No of the noise signal N _b, Compensation can be implemented without excess or deficiency.

FIG. 12 shows a positioning device including a lost motion elimination control device 200c according to the eighth embodiment of the present invention. This lost motion elimination control device 200c is an improvement over the lost motion elimination control device 200b of the seventh embodiment shown in FIG.
Therefore, only a different part from Example 7 is demonstrated, the same code | symbol is attached | subjected to the part same as Example 7, and the overlapping description is abbreviate | omitted.

In the seventh embodiment, when the lost motion is detected, a single noise signal N _b is output. However, in the eighth embodiment, after the lost motion occurs, the noise signal N _b is converged until the lost motion converges. Are repeatedly output continuously.
That is, as shown in FIG. 13, when the motor speed is larger than the load speed, the noise signal _Nb is repeatedly output continuously.
This is because when the lost motion occurs, the motor always precedes the load, so that compensation is made only when the condition is satisfied.
On the contrary, when the load is ahead of the motor, it is a trajectory error unrelated to the lost motion, and therefore, it may be corrected by a commonly used feed forward or feedback mechanism.

Therefore, in Example 8, includes a differentiator 205, the differentiator 205 differentiates the load position signal theta _L, and outputs a load speed signal S.theta _L.
The noise signal generator 204c takes in a load speed signal sθ _L indicating the load speed and a motor speed command V _MO indicating the motor speed.
Then, a initial value No of the noise signal N _b as follows.

(I) When the motor speed command V _MO is larger than the load speed signal sθ _L.
No = (V _MO −sθ _L ) × K
However, K is an arbitrary positive number.
(Ii) When the motor speed command V _MO > 0 and the load speed signal sθ _L <0.
No = 0
(Iii) When the motor speed command V _MO <0 and the load speed signal sθ _L > 0.
No = 0

The calculation for creating the slope of the noise signal N _b is the same as in the seventh embodiment.
In the case of (i) above, that is, when the motor speed command V _MO is continuously larger than the load speed signal sθ _L ,
No = (V _MO −sθ _L ) × K
The noise signal Nb is continuously output.

According to this embodiment, by adding the noise signal N _b sawtooth at the moment of lost motion generation, input, such as dead band or lost motion due to the backlash - it is possible to suppress the hysteresis between the output shaft.

Furthermore, the noise signal N _b, the value is the largest at the moment the output has become a amplitude characteristic whose value gradually decreases with followed the time course.
Therefore, it is possible to engage the teeth of the reduction gear to the output of the noise signal N _b suddenly. Then, by the value of the noise signal N _b by the tapered portion of the noise signal N _b by monotonically decreasing adapt the tooth, it can be attenuated in real vibrations caused by impact in engagement.

Further, since the lost motion continues to repeatedly command the noise signal N _b until convergence, it is possible to suppress lost motion without depending on the state of contact of the clearance and teeth backlash.

FIG. 14 shows a positioning device including a lost motion elimination control device 300b according to Embodiment 9 of the present invention. This lost motion elimination control device 300b is an improvement of the lost motion elimination control device 300 of the third embodiment shown in FIG.
Therefore, only a different part from Example 3 is demonstrated, the same code | symbol is attached | subjected to the part same as Example 3, and the overlapping description is abbreviate | omitted.

In the lost motion elimination control device 300b of the ninth embodiment, the noise signal output signal ON is sent from the noise signal output / stop determination device 303 to the noise signal generation device 304b, and the motor speed command V _MO is sent from the position control unit 11. Will be sent.

The noise signal generator 304b outputs a sawtooth noise signal N _b (see FIGS. 11A and 11B). Timing for outputting the noise signal N _b of the sawtooth is, the noise signal generator 304 in Embodiment 3 is the same as the timing for outputting the noise signal N.

Instructions noise signal generator 304b generates and outputs a noise signal N _b sawtooth is similar to the operation in the noise signal generating device 204b in Embodiment 7 shown in FIG.

According to this embodiment, by adding the noise signal N _b sawtooth at the moment of lost motion generation, input, such as dead band or lost motion due to the backlash - it is possible to suppress the hysteresis between the output shaft.

Furthermore, the noise signal N _b, the value is the largest at the moment the output has become a amplitude characteristic whose value gradually decreases with followed the time course.
Therefore, it is possible to engage the teeth of the reduction gear to the output of a noise signal N _b suddenly. Then, by the value of the noise signal N _b by the tapered portion of the noise signal N _b by monotonically decreasing adapt the tooth, it can be attenuated in real vibrations caused by impact in engagement.

In the example of FIG. 14, the noise signal N _b is superimposed on the motor speed command V _MO , but the noise signal N _b may be superimposed on the position command θ _O and the torque command τ.

Moreover, the technique shown in Examples 4 and 5 can be added.
That is, the state of occurrence of lost motion is determined from the elements of load inertia, coulomb friction, and viscous resistance, and the relationship between the frictional force and the inertial force is obtained from the following equation of motion.
J _L · s ² θ _L + C _L · sθ _L = F
Then, when the frictional force is greater than the inertia force is applied increases the initial value No of the noise signal N _b, if the frictional force is smaller than the inertial force by giving small initial value No of the noise signal N _b, Compensation can be implemented without excess or deficiency.

FIG. 15 shows a positioning device including a lost motion elimination control device 300c according to Example 10 of the present invention. This lost motion elimination control device 300c is an improvement over the lost motion elimination control device 300b of the ninth embodiment shown in FIG.
Therefore, only the parts different from the ninth embodiment will be described, the same parts as those of the ninth embodiment will be denoted by the same reference numerals, and the duplicate description will be omitted.

In the ninth embodiment, when the lost motion is detected, a single noise signal N _b is output. However, in the tenth embodiment, after the lost motion occurs, the noise signal N _b is converged until the lost motion converges. Are repeatedly output continuously.
That is, as shown in FIG. 13, when the motor speed is larger than the load speed, the noise signal _Nb is repeatedly output continuously.
This is because when the lost motion occurs, the motor always precedes the load, so that compensation is made only when the condition is satisfied.
On the contrary, when the load is ahead of the motor, it is a trajectory error unrelated to the lost motion, and therefore, it may be corrected by a commonly used feed forward or feedback mechanism.

Therefore, in the tenth embodiment, the noise speed generator 304c receives the load speed signal sθ _L indicating the load speed and the motor speed command V _MO indicating the motor speed.
Then, a initial value No of the noise signal N _b as follows.

(Vi) When the motor speed command V _MO is larger than the load speed signal sθ _L.
No = (V _MO −sθ _L ) × K
However, K is an arbitrary positive number.
(V) When the motor speed command V _MO > 0 and the load speed signal sθ _L <0.
No = 0
(Vi) When the motor speed command V _MO <0 and the load speed signal sθ _L > 0.
No = 0

The calculation for creating the slope of the noise signal N _b is the same as in the seventh embodiment.
Then, when the above (vi), that is, when the motor speed V _MO is greater state continues than the load speed signal S.theta _L is
No = (V _MO −sθ _L ) × K
The noise signal Nb is continuously output.

According to this embodiment, by adding the noise signal N _b sawtooth at the moment of lost motion generation, input, such as dead band or lost motion due to the backlash - it is possible to suppress the hysteresis between the output shaft.

Furthermore, the noise signal N _b, the value is the largest at the moment the output has become a amplitude characteristic whose value gradually decreases with followed the time course.
Therefore, we are possible to engage the teeth of the reduction gear to the output of the noise signal N _b suddenly. Then, by the value of the noise signal N _b by the tapered portion of the noise signal N _b by monotonically decreasing adapt the tooth, it can be attenuated in real vibrations caused by impact in engagement.

Further, since the lost motion continues to repeatedly command the noise signal N _b until convergence, it is possible to suppress lost motion without depending on the state of contact of the clearance and teeth backlash.

The block block diagram which shows the positioning control apparatus provided with the lost motion cancellation control apparatus which concerns on Example 1 of this invention. Explanatory drawing which shows the operation state of the lost motion cancellation control apparatus which concerns on Example 1. FIG. The block block diagram which shows the positioning control apparatus provided with the lost motion cancellation control apparatus which concerns on Example 2 of this invention. The block block diagram which shows the positioning control apparatus provided with the lost motion cancellation control apparatus which concerns on Example 3 of this invention. The block block diagram which shows the positioning control apparatus provided with the lost motion cancellation control apparatus which concerns on Example 4 of this invention. The characteristic view which shows the amplitude characteristic of the noise signal N. The block block diagram which shows the positioning control apparatus provided with the lost motion cancellation control apparatus which concerns on Example 5 of this invention. The block block diagram which shows the positioning control apparatus provided with the lost motion cancellation control apparatus which concerns on Example 6 of this invention. The block block diagram which shows the positioning control apparatus provided with the lost motion cancellation control apparatus which concerns on Example 7 of this invention. The flowchart which shows the procedure which produces | generates and outputs a sawtooth-shaped noise signal. The wave form diagram which shows a sawtooth-shaped noise signal. The block block diagram which shows the positioning control apparatus provided with the lost motion cancellation control apparatus which concerns on Example 8 of this invention. The characteristic view which shows the relationship between a motor speed and load speed, and the output state of sawtooth noise. The block block diagram which shows the positioning control apparatus provided with the lost motion cancellation control apparatus which concerns on Example 9 of this invention. The block block diagram which shows the positioning control apparatus provided with the lost motion cancellation control apparatus which concerns on Example 10 of this invention. The conceptual diagram which shows the control system which controls the position of the table of a machine tool. Explanatory drawing which shows the relationship between the gear connected with the motor shaft of the motor, and the gear connected to the load side. The characteristic view which shows the position of a table and the position of a motor.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Table 2 Ball screw drive mechanism 3 Motor 4 Reduction gear 10 Feedback control apparatus 11 Position control part 12 Speed control part 13 Current control part 20 NC apparatus 100,100a Lost motion cancellation control apparatus 101 Reading apparatus 102 Speed command detection apparatus 103 Noise signal output 103 Stop determination device 104 Noise signal generation device 200, 200a, 200b Lost motion cancellation control device 203 Noise signal output / stop determination device 204 Noise signal generation device 300, 300a, 300b Lost motion cancellation control device 303 Noise signal output / stop determination device 304 Noise signal generator

Claims (14)

In order to control the position of the load while moving the load by transmitting the force generated by the motor to the load that is the object to be moved by a gear mechanism in which a plurality of gears mesh and transmit the force.
A motor speed command is obtained based on a deviation between the load position signal indicating the load position and the position command, and a torque is obtained based on a deviation between the motor detection speed signal obtained by detecting the motor speed and the motor speed command. A lost motion elimination control device applied to a positioning control device including a feedback control device for obtaining a command and controlling a current value supplied to the motor based on the torque command,
The trajectory data, which is data indicating the movement position of the load, is taken in, and the load position after a preset time is pre-read from the current time point, and it is determined whether the rotation direction of the motor is reversed after the preset time. When it is determined that the rotation direction of the motor is reversed, a reading device that sets a motor rotation direction reversal flag;
When the motor speed command is taken in and the absolute value of the motor speed command is less than a predetermined first determination value, a speed reduction flag is set, and the absolute value of the motor speed command is greater than the predetermined first determination value. A speed command detection device that sets a speed increase flag when the value is greater than or equal to a second determination value;
Outputs a noise signal output signal when the reading device sets an inversion flag and the speed command detection device sets a speed decrease flag, and outputs a noise signal when the speed command detection device sets a speed increase flag A noise signal output / stop determination device that stops signal output;
When the noise signal output / stop determination device outputs a noise signal output signal, a noise signal is output, and the noise signal is added to either the position command or the motor speed command or the torque command, A noise signal generator that stops the output of the noise signal when the noise signal output / stop determination device stops outputting the noise signal output signal; and
A lost motion elimination control device characterized by comprising: In order to control the position of the load while moving the load by transmitting the force generated by the motor to the load that is the object to be moved by a gear mechanism in which a plurality of gears mesh and transmit the force.
A motor speed command is obtained based on a deviation between the load position signal indicating the load position and the position command, and a torque is obtained based on a deviation between the motor detection speed signal obtained by detecting the motor speed and the motor speed command. A lost motion elimination control device applied to a positioning control device including a feedback control device for obtaining a command and controlling a current value supplied to the motor based on the torque command,
The position command and the load position signal are captured, the position command is differentiated to obtain a motor speed signal, the motor speed signal is positive, and a value obtained by subtracting the load position signal from the position command is a positive determination value set in advance. Noise signal output signal is output when the motor speed signal is negative and the value obtained by subtracting the position command from the load position signal is greater than a preset positive determination value. Stops outputting the noise signal output signal when a predetermined time elapses from when the signal is output or when the motor speed signal exceeds the preset threshold speed after the noise signal output signal is output. A noise signal output / stop determination device,
When the noise signal output / stop determination device outputs a noise signal output signal, a noise signal is output, and the noise signal is added to either the position command or the motor speed command or the torque command, A noise signal generator that stops the output of the noise signal when the noise signal output / stop determination device stops outputting the noise signal output signal; and
A lost motion elimination control device characterized by comprising: In claim 2,
A lost motion elimination control apparatus comprising: a sensor for detecting a motor rotation position in the motor; and a sensor signal output from the sensor is used instead of the position command. In order to control the position of the load while moving the load by transmitting the force generated by the motor to the load that is the object to be moved by a gear mechanism in which a plurality of gears mesh and transmit the force.
A motor speed command is obtained based on a deviation between the load position signal indicating the load position and the position command, and a torque is obtained based on a deviation between the motor detection speed signal obtained by detecting the motor speed and the motor speed command. A lost motion elimination control device applied to a positioning control device including a feedback control device for obtaining a command and controlling a current value supplied to the motor based on the torque command,
A differentiator that differentiates the load position signal and outputs a load speed signal;
The motor speed command and the load speed signal are taken in, the motor rotation direction when the motor is rotating / stopped and rotating is detected from the taken motor speed command, and the load is moved from the taken load speed signal.・ Detects the moving direction of the load when stopped and moving, and when the motor rotating direction and load moving direction are in reverse phase, or when the load is stopped and the motor is rotating When the noise signal output signal is output and the predetermined time has elapsed from the time when the noise signal output signal is output, or after the time when the noise signal output signal is output, the motor speed command exceeds the preset threshold speed. A noise signal output / stop determination device that stops the output of the noise signal output signal when it becomes large,
When the noise signal output / stop determination device outputs a noise signal output signal, a noise signal is output, and the noise signal is added to either the position command or the motor speed command or the torque command, A noise signal generator that stops the output of the noise signal when the noise signal output / stop determination device stops outputting the noise signal output signal; and
A lost motion elimination control device characterized by comprising: In claim 4,
A lost motion elimination control device comprising a sensor for detecting a load speed of the load instead of the differentiator, and using a sensor signal output from the sensor instead of the load speed signal. In claim 1,
A speed / acceleration creating means for obtaining a load speed signal sθ _L that is the speed of the load and for obtaining a load acceleration signal s ² θ _L that is the acceleration of the load;
The noise signal generator is
When the load moment of inertia is J _L , the resistance between the load and the sliding part is C _L , and the external force due to Coulomb friction is F,
^{_{| J L · s 2 θ L}} + C L · sθ L | <F
If it becomes, the amplitude of the noise signal N is set to a preset amplitude value,
^{_{| J L · s 2 θ L}} + C L · sθ L |> F
The lost motion elimination control device is characterized in that, when it becomes, the amplitude of the noise signal N is made smaller than a preset set amplitude value. In claim 2 or claim 3,
A speed / acceleration creating means for obtaining a load speed signal sθ _L that is the speed of the load and for obtaining a load acceleration signal s ² θ _L that is the acceleration of the load;
The noise signal generator is
When the load moment of inertia is J _L , the resistance between the load and the sliding part is C _L , and the external force due to Coulomb friction is F,
^{_{| J L · s 2 θ L}} + C L · sθ L | <F
If it becomes, the amplitude of the noise signal N is set to a preset amplitude value,
^{_{| J L · s 2 θ L}} + C L · sθ L |> F
The lost motion elimination control device is characterized in that, when it becomes, the amplitude of the noise signal N is made smaller than a preset set amplitude value. In claim 4 or claim 5,
An acceleration creating means for obtaining a load acceleration signal s ² θ _L that is an acceleration of the load;
The noise signal generator is
When the load moment of inertia is J _L , the resistance between the load and the sliding part is C _L , and the external force due to Coulomb friction is F,
^{_{| J L · s 2 θ L}} + C L · sθ L | <F
If it becomes, the amplitude of the noise signal N is set to a preset amplitude value,
^{_{| J L · s 2 θ L}} + C L · sθ L |> F
The lost motion elimination control device is characterized in that, when it becomes, the amplitude of the noise signal N is made smaller than a preset set amplitude value. In any one of Claims 1 thru | or 8,
The noise signal generator is characterized in that when outputting a noise signal, the amplitude of the noise signal is gradually increased to a set amplitude, and when stopping the noise signal, the amplitude of the noise signal is gradually decreased and then stopped. Lost motion elimination control device. In any one of Claims 1 to 9,
The lost motion elimination control apparatus, wherein the noise signal output from the noise signal generation apparatus is a repetitive signal or a pulse signal. In order to control the position of the load while moving the load by transmitting the force generated by the motor to the load that is the object to be moved by a gear mechanism in which a plurality of gears mesh and transmit the force.
A motor speed command is obtained based on a deviation between the load position signal indicating the load position and the position command, and a torque is obtained based on a deviation between the motor detection speed signal obtained by detecting the motor speed and the motor speed command. A lost motion elimination control device applied to a positioning control device including a feedback control device for obtaining a command and controlling a current value supplied to the motor based on the torque command,
The position command and the load position signal are captured, the position command is differentiated to obtain a motor speed signal, the motor speed signal is positive, and a value obtained by subtracting the load position signal from the position command is a positive determination value set in advance. Noise signal output signal is output when the motor speed signal is negative and the value obtained by subtracting the position command from the load position signal is greater than a preset positive determination value. Stops outputting the noise signal output signal when a predetermined time elapses from when the signal is output or when the motor speed signal exceeds the preset threshold speed after the noise signal output signal is output. A noise signal output / stop determination device,
The motor speed command is taken in, the motor rotation direction is determined based on the motor speed command, the noise signal output / stop determination device outputs a noise signal output signal, and the motor rotation direction is a positive direction. When the determination is made, the amplitude value at the time of output is positive, the amplitude value gradually decreases with the passage of time thereafter, and finally a sawtooth noise signal having an amplitude value of zero is output. When the noise signal output / stop determination device outputs a noise signal output signal in addition to either the position command, the motor speed command or the torque command, and determines that the rotation direction of the motor is negative. A sawtooth noise signal is output in which the amplitude value at the time of output is negative, the amplitude value gradually decreases with time, and finally the amplitude value becomes zero, and this noise signal is output to the position command or In addition to any one of the motor speed or the torque command, when the noise signal output-stop determination device stops the output of the noise signal output signal, and a noise signal generator for stopping the output of the noise signal,
A lost motion elimination control device characterized by comprising: In claim 11,
The lost motion elimination control device, wherein the noise signal generator continuously outputs the sawtooth noise signal when the motor speed command is larger than the load speed signal. In order to control the position of the load while moving the load by transmitting the force generated by the motor to the load that is the object to be moved by a gear mechanism in which a plurality of gears mesh and transmit the force.
A motor speed command is obtained based on a deviation between the load position signal indicating the load position and the position command, and a torque is obtained based on a deviation between the motor detection speed signal obtained by detecting the motor speed and the motor speed command. A lost motion elimination control device applied to a positioning control device including a feedback control device for obtaining a command and controlling a current value supplied to the motor based on the torque command,
A differentiator that differentiates the load position signal and outputs a load speed signal;
The motor speed command and the load speed signal are taken in, the motor rotation direction when the motor is rotating / stopped and rotating is detected from the taken motor speed command, and the load is moved from the taken load speed signal.・ Detects the moving direction of the load when stopped and moving, and when the motor rotating direction and load moving direction are in reverse phase, or when the load is stopped and the motor is rotating When the noise signal output signal is output and the predetermined time has elapsed from the time when the noise signal output signal is output, or after the time when the noise signal output signal is output, the motor speed command exceeds the preset threshold speed. A noise signal output / stop determination device that stops the output of the noise signal output signal when it becomes large,
The motor speed command is taken in, the motor rotation direction is determined based on the motor speed command, the noise signal output / stop determination device outputs a noise signal output signal, and the motor rotation direction is a positive direction. When the determination is made, the amplitude value at the time of output is positive, the amplitude value gradually decreases with the passage of time thereafter, and finally a sawtooth noise signal having an amplitude value of zero is output. When the noise signal output / stop determination device outputs a noise signal output signal in addition to either the position command, the motor speed command or the torque command, and determines that the rotation direction of the motor is negative. A sawtooth noise signal is output in which the amplitude value at the time of output is negative, the amplitude value gradually decreases with time, and finally the amplitude value becomes zero, and this noise signal is output to the position command or In addition to any one of the motor speed or the torque command, when the noise signal output-stop determination device stops the output of the noise signal output signal, and a noise signal generator for stopping the output of the noise signal,
A lost motion elimination control device characterized by comprising: In claim 13,
The lost motion elimination control device, wherein the noise signal generator continuously outputs the sawtooth noise signal when the motor speed command is larger than the load speed signal.

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