JP2008059016A - Positioning controller and positioning control method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a positioning controller and a positioning control method for detecting the temperature of an object loading section and a position detector section such as a linear scale in the case of performing the working, cutting, and conveyance of an object, and to calculate the correction quantity of the thermal expansion quantity or thermal contraction quantity of an object loading section and a position detector section accompanied with temperature change, and to correct the moving quantity of a traveling object based on the correction quantity, and to improve the working precision, cutting precision, and conveyance positioning precision of the object. <P>SOLUTION: This positioning controller is provided with: a temperature signal processing part for processing a detection signal as the temperature change of a positioning stage; a position detection means; and a position correction processing part for calculating position deviation accompanied with the thermal expansion or thermal contraction of the positioning object as position correction quantity, and configured to perform the positioning control of a motor based on the position correction quantity. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a positioning control apparatus and positioning control method for a moving body that drives a machine or the like with a servo motor or the like to perform processing, cutting, conveyance, etc. of an object, and in particular, easily eliminates the influence of temperature disturbance. The present invention relates to a positioning control device and a positioning control method for obtaining good positioning accuracy.

  A first conventional positioning control device includes a movable stage in which a moving positioning object and a gauge for detecting the position of the positioning object are provided at positions separated from each other, and the movable stage moves to move the moving object. A fixed stage provided with an object that is substantially coincident with the positioning object, position detection means for reading the gauge and detecting the position of the positioning object, and the fixing stage and the position detection means; A base member that is fixed at a distant position, and even if a temperature change occurs in the movable stage and the base member, a change in an interval between the positioning object provided on the movable stage and the gauge, and the base It is configured such that the change in the distance between the position detection means provided on the member and the fixed stage is canceled out. Furthermore, a temperature detection means and a control means for controlling the positioning of the movable stage are provided. The positioning control method is based on a signal obtained from the temperature detection means, and the control means moves the moving distance of the movable stage. Is corrected (for example, see Patent Document 1).

  Further, the second conventional positioning control device is configured to detect a current position of the moving table on the basis of a moving table that moves on the base plate by driving means and a reflected light of a mirror that is integral with the moving table. Detecting means; at least one temperature sensor for detecting the temperature of the moving table; computing means for calculating a deformation amount of the moving table based on the output; output of the current position detecting means; Control means for controlling the drive amount of the drive means based on the output is provided. In addition, a plurality of temperature sensors are respectively disposed at a plurality of parts of the moving table, and the calculation means is configured to employ one of the outputs of each of the plurality of temperature sensors. It is also configured to calculate the deformation amount of each part of the moving table based on the output. Moreover, it is also configured to correct the output of the calculation means based on the change in the center position of positioning of the positioning target object held on the moving base (for example, see Patent Document 2).

Further, in the conventional positioning control method, the detection sensor of the target object is arranged near the longest stroke end position of the target object, separated from the feed screw, and the command unit has a predetermined per unit time for directing the target object to a predetermined stop position. A command signal having the number of pulses is output. First, during the period from the origin position of the target object to the detection position of the target object by the detection sensor, based on the command signal of a predetermined number of pulses from the command unit, After the object is driven and transferred by speed control under a first control system having a pulse generating encoder linked to the sensor and a servo drive unit connected thereto, and then the object is detected by the detection sensor, A detection sensor, a calculation unit that inputs a detection signal from the detection sensor and calculates the number of pulses up to a predetermined stop position of the object, and a position update unit that inputs and counts the calculation result Under the second control system, which is added to the first control system, the object is stopped at a predetermined position by position control based on the specified number of pulses, thereby performing advanced positioning in the long stroke transfer of the object Accuracy is obtained (see, for example, Patent Document 3).

FIG. 4 is a schematic configuration diagram showing the configuration of the first conventional positioning control device. In the figure, 30 is a positioning device, 31 is a vibrator, 32 is a moving element, 33 is a vibration motor, 34 is a movable stage, 55 is a guide member, 57 is a fixed stage, 60 is a base member, and the positioning device 30 is a base. It has a member 60, a guide member 55, a movable stage 34, a fixed stage 57, and a vibration motor 33 having a mover 32 and a vibrator 31.
Changes in the distance between the positioning object 56 moved by the movable stage 34 and the gauge 59c for detecting the position of the movable stage 34, and the distance between the fixed stage 57 fixed to the base member 60 and the position detection unit 59. The change is offset.
As described above, the first conventional positioning control device is configured to cancel the misalignment due to thermal expansion or contraction, prevents misalignment, and has high alignment accuracy.

FIG. 5 is a schematic configuration diagram showing a configuration of a second conventional positioning control device. In the figure, E1 is a positioning stage device, 1 is a platform, 2 is a moving table, 3 is a linear motor, 4 is a laser interferometer, 5 is a temperature sensor, 1a is a guide surface, 2a is a mirror, 2b is a static pressure pad, 3a is a driver, 4a is a controller, 5a is an amplifier, and 5b is an arithmetic unit. The moving table 2 is moved by the linear motor 3, and the laser interferometer 4 detects the current position of the moving table 2 from the reflected light of the mirror 2 a and feeds it back to the driver 3 a of the linear motor 3. Detected by the sensor 5, the output is introduced into the arithmetic unit 5b, the change in the separation distance between the positioning target object W1 and the reflecting surface of the mirror 2a is obtained and introduced into the driver 3a, and the drive amount of the linear motor 3 is corrected. is doing.
As described above, the second conventional positioning control device detects the temperature of the movable table 2 by the temperature sensor 5 to obtain a positional deviation (change in the separation distance), corrects the drive amount of the linear motor 3 and changes the temperature. This prevents a decrease in positioning accuracy.

FIG. 6 is a schematic configuration diagram showing a configuration for implementing a conventional positioning control method. In the figure, 1 is a command unit, 2 is a position update unit, 3 is a servo drive unit, a large frame 4 shows a drive unit, 5 in the frame 4 is a servo motor (M), 6 is an encoder (E), 7 is a ball screw as a feed screw, 8 is an object to be positioned, 9 is a photoelectric switch as a detection sensor, and 10 is an arithmetic unit. In the vicinity of the longest stroke position, the detection sensor 9 for the object 8 is separated from the feed screw 7, and the object 8 is detected by the servo mechanism based on a command from the command unit 1 storing the position information of the object 8. The detection position is transferred by speed control, and the detection position to the positioning position is transferred by position control and stopped.
As described above, the conventional positioning control method is a control method in which a temperature detection unit is provided separately, and a temperature change from the reference temperature of the detected temperature is fed back to the command unit to perform temperature correction on the position command for the positioning target object. In addition, an expensive position detector or the like is not provided, and the long stroke transfer of the positioning object 8 is eliminated without the influence of the temperature disturbance and a good positioning accuracy is obtained without making a large investment.
JP 2001-235692 A (page 4-10, FIG. 1) JP-A-8-137550 (page 3-5, FIG. 1) JP-A-8-044331 (page 4-5, FIG. 1)

  The first conventional positioning control device shown in FIG. 4 includes a change in the distance between the positioning object 56 moved by the movable stage 34 and the gauge 59c for detecting the position of the movable stage 34, and the base member 60. Since the change in the interval between the fixed stage 57 and the position detecting unit 59 fixed to each other cancels out, that is, the relative position between the positioning object 56 and the movable stage 34 on which the positioning target 56 is mounted is detected and canceled out. Therefore, when the positioning target 56 itself has a thermal expansion or contraction, the absolute position of the positioning target 56 cannot be detected, and there is a problem that a positional deviation occurs.

The second conventional positioning control device shown in FIG. 5 is for driving an expensive system using the laser interferometer 4, and for driving an inexpensive system using a generally used linear scale or the like. There is a problem that the configuration and method cannot be applied.

The conventional positioning control method shown in FIG. 6 relates to a relatively old technology for driving a feed screw drive system that does not use a linear scale or the like, and an inexpensive system that uses a linear scale or the like that is generally used in recent years. There is a problem that application in the case of driving is not taken into consideration and the configuration and method cannot be applied.

  The present invention has been made in view of such problems, and detects the temperature of an object mounting portion and a position detector portion such as a linear scale when processing, cutting, conveying, etc. of the object, Calculates the amount of correction for the amount of thermal expansion or thermal contraction of the object mounting part and position detector part that accompanies the change, and corrects the amount of movement of the moving object based on the amount of correction. An object of the present invention is to provide a positioning control device and a positioning control method capable of improving the conveyance positioning accuracy.

In order to solve the above problem, the present invention is configured as follows.
The invention according to claim 1 is a temperature change of the positioning stage in a positioning control device for driving a positioning stage on which a positioning object is mounted and moved, comprising a position detecting means, a temperature detecting means, and a motor. A temperature signal processing unit that processes a detection signal; and a position correction processing unit that calculates a position shift associated with thermal expansion or thermal contraction of the position detection unit and the positioning object as a position correction amount, and the position correction amount. The positioning of the motor is controlled based on the above.

  According to a second aspect of the present invention, the position correction processing unit according to the first aspect of the present invention is configured such that the coefficient of thermal expansion of the position detecting unit and the coefficient of thermal expansion of the positioning object and the position detecting unit are The position correction amount is calculated based on the difference and the detection signal.

  According to a third aspect of the invention, the position correction processing unit according to the first aspect of the invention further aligns the end of the positioning object with respect to a reference position on the movable side table of the positioning stage. The position correction amount is calculated based on the measurement distance determined by combining the fixed position and the reference position of the position detecting means.

  According to a fourth aspect of the present invention, the position correction processing unit according to the first aspect of the invention further aligns the center of the positioning object with respect to a reference position on the movable side table of the positioning stage. The position correction amount is calculated based on the measurement distance determined by combining the fixed position and the reference position of the position detecting means.

  According to a fifth aspect of the present invention, the temperature detecting means in the first aspect of the invention is arranged in the vicinity of the position detecting means.

  The invention according to claim 6 drives a positioning stage that includes a position detection means, a temperature detection means, and a motor and mounts and moves a positioning object, and based on a detection signal of the temperature detection means, In the positioning control method for correcting the moving distance of the movable side table of the positioning stage, a mounting position adjusting process is performed in which the end of the positioning object is aligned and fixed with respect to a reference position on the movable side table, and the position The reference position of the detecting means and the reference position on the movable table are matched, and the combined position is stored as the movable reference position of the movable table, and the motor is turned on according to the position command. The position detecting means performs temperature detection processing for controlling the positioning and detecting a temperature change of the positioning stage by the temperature detecting means. A position correction amount for a current position detected by the position detection unit is calculated based on a thermal expansion rate, a difference in thermal expansion coefficient between the positioning object and the position detection unit, and the temperature change. Correction amount calculation processing is performed, and the position correction amount is used for positioning control of the motor.

  According to a seventh aspect of the present invention, the temperature detection process and the position correction amount calculation process in the sixth aspect of the invention are repeatedly continued while positioning the motor in accordance with the position command.

  According to an eighth aspect of the invention, in place of the mounting position adjustment process in the sixth aspect of the invention, the center of the positioning object is fixed to a reference position on the movable table. To process.

According to the first to fourth or fourth to sixth aspects of the present invention, the thermal expansion amount or thermal contraction amount of the positioning object and the position detecting means (linear scale) accompanying the temperature change of the positioning stage is calculated. be able to. In addition, it is possible to correct the positional deviation accompanying the temperature change of the positioning stage, and it is possible to improve the processing accuracy, cutting accuracy, and conveyance positioning accuracy of the object in the positioning control of the motor.
Further, according to the invention described in claim 5, the positioning accuracy can be easily improved at low cost.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

FIG. 1 is a schematic configuration diagram of a positioning control device of the present invention. In the figure, 1 is a positioning control device, 2 is a positioning stage, 3 is an electric motor (motor), 4 is a position detector such as an encoder or linear scale, 5 is a temperature sensor, 11 is a position or speed control unit, and 12 is current control. , 13 is an inverter unit, and 14 is an FB (feedback) signal processing unit. Reference numeral 21 denotes a temperature signal processing unit, and 22 denotes a position correction processing unit. A configuration in which the electric motor 2 is driven in response to the input of the position command and the position detection signal or speed detection signal which is the output of the command and the FB signal processing unit 14 (the electric motor 2, the position detector 3, the position or speed control unit) 11, the current control unit 12, the inverter unit 13, and the FB signal processing unit 14) are configurations obtained by a well-known technique, and thus detailed description thereof is omitted.
The present invention is different from the prior art in that the positioning stage 2 includes a temperature sensor 5 and the positioning control device 1 includes a temperature signal processing unit 21 and a position correction processing unit 22. This is a positioning control method for controlling the electric motor based on the correction amount obtained by the unit 22.

  FIG. 2 is a flowchart showing the positioning control method of the present invention, and FIG. 3 is a schematic configuration diagram of the positioning stage 2 for explaining the positioning control method of the present invention. 2 and 3, the positioning control method of the present invention will be described. Here, the electric motor 2 in FIG. 1 is described as the linear motor stator 103 and the linear motor movable element 104 in FIG. 3, and the position detector 3 in FIG. 1 is described as the linear scale 106 and the position detection head 107 in FIG. . 3 shows the positioning stage 2 including the linear guide 105, the positioning stage 2 having an air bearing may be used.

  (Step 1) When the object 8 is mounted on the movable table 102, the object 8 is fixed and mounted so that the end of the object 8 is aligned with the reference position on the movable table 102, and the process proceeds to Step 2. Since the reference position on the movable table 102 is determined in advance when the object 8 is mounted, the object 8 can be arbitrarily fixed and mounted. In addition, it is desirable that the alignment work is fixed within a desired positioning accuracy using a jig or the like to such an extent that a temperature change described later can be ignored.

(Step 2) The reference position of the linear scale 106 (point A in FIG. 3) and the reference position on the movable side table 102 (point B in FIG. 3) are matched, and the process proceeds to step 3. The alignment operation is performed by, for example, moving and positioning the movable side table 102 to such an extent that a temperature change described later can be ignored. The stage may be moved by, for example, returning to the origin.

  (Step 3) The current position of the movable table 102 is stored as a reference position, and the process proceeds to Step 4. The current position of the movable table 102 is detected by a position detection head 107 facing the linear scale 106, and the detection signal is signal-processed by the FB signal processing unit 14. If the difference between the reference position of the linear scale 106 (point A in FIG. 3) and the reference position on the movable table 102 (point B in FIG. 3) is known in advance, and the difference is stored, The processing of step 2 and step 3 need not be performed.

  (Step 4) The positioning control device 1 controls the inverter unit 13 in FIG. 1 based on the input position command and a corrected feedback signal described later, and drives the linear motor to move the mover table 102. Further, the temperature change of the positioning stage 2 at this time is detected by the temperature sensor 109, the detection signal is signal-processed by the temperature signal processing unit 21, and the process proceeds to Step 5. Here, it is desirable that the temperature sensor 109 is mounted on the positioning stage 2 in the vicinity of the linear scale 106 of the fixed side table 101, for example. Further, when the positioning stage 2 is configured, since the heat radiation time constant of the heat generated when the linear motor is driven is large, it can be considered that the temperature change near the object 8 and the temperature change near the linear scale 106 are substantially the same. The number of temperature sensors 109 attached can also be one.

(Step 5) For example, the position of the point B ′ in FIG. 3 is calculated based on Expression (1), and the process proceeds to Step 6.
θ _{B ′} = θ _B × (1 + ρ ₁ t) + θ _B1 × (1 + ρ ₂ t) (1)
Here, θ _B is the distance between point _B and point A, θ _B1 is the distance between point B ′ and point B, ρ ₁ is the expansion coefficient of the linear scale 106, and ρ ₂ is the linear scale 106 and the object 8. The difference in expansion coefficient, t, is the detected temperature. [rho ₁ is the known value seen in the material specification of the linear scale 106, [rho ₂ is a known value seen in the material specifications of the material specifications and the linear scale 106 of the object 8, Moreover, theta _B Step 3 is a distance determined by the position detected by the position detection head 107 facing the linear scale 106 after processing, and θ _B1 is a known value indicating the width (length) of the object 8.
Therefore, θ _B × (1 + ρ ₁ t) means the thermal expansion amount or thermal contraction amount of the linear scale 106, and θ _B1 × (1 + ρ ₂ t) means the thermal expansion amount or thermal contraction amount of the object 8. To do.

  (Step 6) The position calculated based on the equation (1) is corrected as a correction amount considering the thermal expansion amount or thermal contraction amount of the object 8 and the linear scale 106, etc. Is output to the position or speed control unit at, and the process proceeds to step 7.

(Step 7) It is determined whether or not the process of moving the mover table 102 by driving the linear motor is continued. If the process is continued, the processes of Steps 4 to 6 are repeated. For example, the repetition is performed every predetermined time. When not continuing, a series of processes are complete | finished.

In the process of step 1, when the object 8 is mounted on the movable table 102, the object 8 is first fixed, and the positional deviation between the end of the object 8 and the reference position on the movable table 102 is corrected. It is good also as (theta) _B in Formula (1) by measuring.
Further, in the processing of step 1, even when the center of the object 8 is aligned with the reference position on the movable table 102 instead of the end of the object 8, the correction amount is calculated in the same manner based on the equation (1). it can.

It is a schematic block diagram of the positioning control apparatus of this invention. It is a flowchart which shows the positioning control method of this invention. It is a schematic block diagram of the positioning stage 2 for demonstrating the positioning control method of this invention. It is a schematic block diagram which shows the structure of the 1st conventional positioning control apparatus. It is a schematic block diagram which shows the structure of the 2nd conventional positioning control apparatus. It is a schematic block diagram which shows the structure which implements the conventional positioning control method.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Positioning control apparatus 2 Positioning stage 3 Electric motor (motor)
4 position detector 5 temperature sensor 11 position or speed control unit 12 current control unit 13 inverter unit 14 FB (feedback) signal processing unit 21 temperature signal processing unit 22 position correction processing unit 101 fixed side table 102 movable side table 103 linear motor fixed Child 104 Linear motor mover 105 Linear guide 106 Linear scale 107 Position detection head 108 Object 109 Temperature sensor

Claims (8)

In a positioning control device for driving a positioning stage for mounting and moving a positioning object, comprising a position detecting means, a temperature detecting means, and a motor,
A temperature signal processing unit that processes a detection signal that is a temperature change of the positioning stage;
A position correction processing unit that calculates a positional shift associated with thermal expansion or thermal contraction of the position detection unit and a positional shift associated with thermal expansion or thermal contraction of the positioning object as a position correction amount;
A positioning control device that controls the positioning of the motor based on the position correction amount.   The position correction processing unit calculates the position correction amount based on a thermal expansion coefficient of the position detection unit, a difference in thermal expansion coefficient between the positioning object and the position detection unit, and the detection signal. The positioning control device according to claim 1. The position correction processing unit is further configured to align and fix the end of the positioning object with respect to a reference position on the movable side table of the positioning stage; and
A reference position of the position detecting means;
The positioning control apparatus according to claim 1, wherein the position correction amount is calculated based on a measurement distance determined by combining the two. The position correction processing unit is further fixed to the reference position on the movable side table of the positioning stage with the center of the positioning object aligned and fixed,
A reference position of the position detecting means;
The positioning control apparatus according to claim 1, wherein the position correction amount is calculated based on a measurement distance determined by combining the two.   The positioning control device according to claim 1, wherein the temperature detection unit is disposed in the vicinity of the position detection unit. A position detection means, a temperature detection means, and a motor, which is equipped with a motor, drives a positioning stage on which a positioning object is mounted and moves, and based on a detection signal of the temperature detection means, a moving distance of the movable side table of the positioning stage In a positioning control method for correcting
A mounting position alignment process for fixing and fixing the end of the positioning object with respect to a reference position on the movable table,
A reference position alignment process is performed in which a reference position of the position detection unit and a reference position on the movable side table are matched, and the combined position is stored as a movable reference position of the movable side table,
In addition to controlling the positioning of the motor in accordance with a position command, the temperature detecting means detects a temperature change of the positioning stage by the temperature detecting means,
The position correction amount of the current position detected by the position detection means based on the thermal expansion coefficient of the position detection means, the difference in thermal expansion coefficient between the positioning object and the position detection means, and the temperature change To calculate the position correction amount,
A positioning control method, wherein the position correction amount is used for positioning control of the motor.   The positioning control method according to claim 6, wherein the temperature detection process and the position correction amount calculation process are repeatedly continued while the motor is positioned in accordance with the position command.   The positioning control method according to claim 6, wherein a process of aligning and fixing the center of the positioning object with respect to a reference position on the movable side table is performed instead of the mounting position alignment process.

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