JP2005253212A - Precision positioning device and its control parameter adjusting method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a precision positioning device of such a structure as a user can easily touch the adjusting part, e.g. the control parameters, in a controller of a precision positioning stage, more specifically, adjustment volume of "P component", "I component" and "D component" of the control parameters are added and alteration of parameters can be carried out easily on the user side as addition is altered, and to provide its control parameter adjusting method. <P>SOLUTION: In the precision positioning device comprising a positioning stage (3) provided with a piezoelectric actuator and a capacitive position sensor (4), P component, I component and D component of the control parameters of a precision positioning stage can be adjusted individually. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a precision positioning device using a piezoelectric actuator and a method for adjusting control parameters thereof.

In recent years, positioning composed of a positioning stage equipped with a piezoelectric actuator and a capacitive position detection sensor for fine positioning of magnetic head inspection devices that require precise movement accuracy in nanometer units and inspection devices in the semiconductor and optical fields. Devices have been used frequently.
However, in conventional positioning devices, there are variations in processing when manufacturing sensor probes that house capacitive position detection sensors, which are component parts. Therefore, sensor amplifiers with individual accuracy adjustments for each sensor probe When the sensor probe is damaged, it is necessary to replace the sensor amplifier adjusted with high accuracy together.

As a solution to the above problems,
"Positioning device comprising positioning stage equipped with piezoelectric actuator and capacitive position detection sensor, positioning device that provides position detection signal gain and offset adjustment unit in sensor amplifier or positioning stage controller" is known It has been. (See Patent Document 1)

The positioning device described in the above publication is as follows.
FIG. 5 shows a schematic configuration diagram of a positioning stage provided with the piezoelectric actuator.
In FIG. 5, reference numeral 1 denotes a piezoelectric actuator, and a stage 3 provided at the center of the base 2 of the positioning stage is supported by support portions provided at four corners of the stage 3 and is in a finely movable state. Grooved.
Reference numeral 4 denotes a capacitance type position detection sensor probe, which is assembled with high accuracy into a mounting hole provided in the base 3 via a sensor holder 5.

With the above configuration, when a voltage is applied to the piezoelectric actuator 1 in the stage 3 incorporated in the base body 2, a slight displacement of the piezoelectric actuator 1 is transmitted to the stage, and the stage moves accordingly.
Here, since the capacitance type position detection sensor probe 4 is housed in the base 2, the detection result of the capacitance of the sensor is converted into a position change amount by a sensor amplifier and the stage is moved while being fed back. And the amount of movement of the stage can be precisely controlled.

However, when manufacturing the capacitance type position detection sensor probe, since there is a processing variation due to machining, a sensor amplifier in which individual accuracy adjustment is performed for each sensor probe is incorporated in the positioning device. When the sensor probe is broken during use, there is a problem that accurate positioning accuracy cannot be obtained even if the sensor probe is replaced with another sensor probe, and the accuracy is shifted.
In order to solve this problem, focusing on the fact that this accuracy deviation does not affect the linearity error, but only the gain and offset of the position detection signal, the capacitance and capacitance of the positioning stage equipped with the piezoelectric actuator In a positioning device composed of a mold position detection sensor, a position detection signal gain and offset adjustment unit is provided in a sensor amplifier or a positioning stage controller to constitute a positioning device.

A block diagram of the positioning stage is shown in FIG.
The positioning stage 3 in FIG. 6 is assembled with a piezoelectric actuator 1 for finely moving the stage and a capacitive sensor probe 4 for detecting the operation.
A CPU (not shown) is mounted on the positioning controller, and includes a communication unit 10b that receives a command from the external host 11 in hardware and a calculation unit 10a that calculates input and output for PID control. Works with software.

Here, the sensor amplifier is a dedicated amplifier for converting a signal detected by detecting a change in position as a change in capacitance with a capacitance type sensor probe mounted on the positioning stage into a standardized voltage signal.
With the above-described configuration, the current position of the positioning stage is detected by a capacitive sensor in response to a position command given by the host, the operation amount is determined by PID calculation from the position command and the current position, and the positioning stage is moved through the piezoelectric amplifier It comes to drive.

In order to maintain compatibility with each sensor probe, the gain and offset adjustment unit of the position detection signal is installed with a socket or the like so that it can be easily replaced with the sensor input first stage in the positioning controller. (Similar effects can be obtained by providing a position detection signal gain and offset adjustment unit in the sensor amplifier.)
JP 2002-31176 A (FIGS. 1 and 2 and (0004) to (0012)

The power waveform for driving the piezoelectric actuator (piezo element) of the precision positioning stage as described above varies depending on the control parameter.
An example thereof will be described with reference to FIG.
FIG. 7A shows a case where the control parameters are set optimally, and an almost ideal trapezoidal wave rise occurs.
FIG. 7B shows a case where the control parameter is set to be overshoot, and the waveform gradually converges with a large overshoot at the start.
FIG. 7C shows a case where the control parameter is set to a value that oscillates, and has a waveform that greatly overshoots at the rise and continues to oscillate thereafter.

  In the conventional precision positioning stage controller, the adjustment of the control parameters for adjusting the waveform is fixed at the time of delivery or is limited to the adjustment by the communication command from the host computer, and is changed on the user side. That was not easy.

  An object (object) of the present invention is to provide a structure in which a user can easily touch an adjustment part of a control parameter or the like in a controller of a precision positioning stage. Specifically, the control parameter includes “P component”, “I component” and An object of the present invention is to provide a precision positioning apparatus and a method for adjusting control parameters thereof, which can add a “D component” adjustment volume to easily change parameters in accordance with the change of addition on the user side.

  In order to solve the above-mentioned problem, in a precision positioning device including a positioning stage having a piezoelectric actuator and a capacitance type position detection sensor, P component, I component, and D component of the control parameters of the positioning stage are It is characterized by being individually adjustable. (Claim 1)

  The individual adjustments of the P component, the I component, and the D component of the control parameters of the positioning stage are performed by an adjustment knob that can be adjusted by a user on the panel portion of the precision positioning device. (Claim 2)

  Further, the adjustment of the control parameter is executed in accordance with the change of the load mounted on the positioning stage. (Claim 3)

  According to the precision positioning device and the control parameter adjustment method thereof according to claims 1 to 3, the adjustment is individually performed by using the adjustment volume of the “P component”, “I component”, and “D component” of the control parameters in the precision positioning device. be able to.

The configuration of the fine movement positioning stage provided with the piezoelectric actuator of the present invention is the same as that of the conventional one shown in FIG.
Next, a block diagram of the positioning stage of the present invention is shown in FIG.
The positioning stage 3 in FIG. 1 is assembled with a piezoelectric actuator 1 for finely moving the stage and a capacitive sensor probe 4 for detecting the operation, as in the conventional stage in FIG.
The positioning controller 10 is equipped with a CPU (not shown), and includes a communication unit 10b that receives a command from the external host 11 in hardware and a PID calculation unit 10a that calculates input and output for PID control. The software works.

Here, the sensor amplifier is a dedicated amplifier for converting a signal detected by detecting a change in position as a change in capacitance with a capacitance-type sensor probe mounted on the positioning stage into a standardized voltage signal.
With the above-described configuration, the current position of the positioning stage is detected by a capacitive sensor in response to a position command given by the host, the operation amount is determined by PID calculation from the position command and the current position, and the positioning stage is moved through the piezoelectric amplifier It comes to drive.

A feature of the present invention is that an adjustment volume for changing “P component”, “I component”, and “D component” of the control parameters is provided in the PID adjustment unit in order to cope with a change in the load installed on the positioning stage. An object of the present invention is to provide a fine movement positioning stage in which 10c is added to a panel portion, and a parameter can be easily changed along with the additional change on the user side.
The gain and offset adjustment unit for the position detection signal is provided in the PID adjustment unit 10c in the positioning controller similarly to the conventional one in FIG.

A conceptual diagram of the PID adjustment unit is shown in FIG. 2 using FIG.
As shown in FIG. 2, the PID adjustment unit 10c provided in the panel portion includes a P constant setting knob connected to a variable resistor, an I constant setting, in order to individually adjust the P component, the I component, and the D component. It consists of a knob and a D constant setting knob.
In FIG. 2, the individual adjustment circuit is configured by a variable resistor, but it goes without saying that it may be configured by other elements.

Next, adjustment volume adjustment 1 for changing the control parameters “P component”, “I component” and “D component” in order to cope with a change in the load installed on the positioning stage of the present invention. An example will be described.
In FIG. 3, the control parameters “P component”, “I component” and “D component” are adjusted while the output of the piezo amplifier is connected to the oscilloscope 14 and the output waveform is observed.

FIG. 4 shows an example of the output waveform when the P component and D component are fixed and only the I component is adjusted.
FIG. 4A shows an output waveform before adjustment, which is an overshoot waveform similar to that shown in FIG. 7B.
FIG. 4B shows the result of adjusting the I component using the I constant setting knob for the purpose of adjusting the I component in order to adjust the output waveform.
From FIG. 4B, it can be understood that the amount of overshoot is reduced.
Further, FIG. 4C shows the result of adjusting the I component using the I constant setting knob for adjusting the I component in order to adjust the output waveform.
From FIG. 4C, it can be understood that the output waveform is close to the ideal rise of the trapezoidal wave, and the adjustment is completed.
In FIG. 4, the P component and the D component are fixed and only the I component is adjusted. However, depending on the case, the P component and the D component may be adjusted.

  According to the precision positioning device and the control parameter adjusting method of the present invention, the control parameters of the precision positioning device can be individually adjusted by the adjustment volume of the “P component”, “I component” and “D component”. Industrial applicability is enormous.

FIG. 1 is a diagram showing a block configuration of a positioning stage according to the present invention. FIG. 2 is a diagram showing the concept of the PID adjustment unit in the present invention. FIG. 3 is a diagram showing a state in which the control parameters “P component”, “I component”, and “D component” are adjusted by observing the output waveform of the oscilloscope in the present invention. FIG. 4 is a diagram illustrating an output waveform when only the I component is adjusted while fixing the P component and the D component in the present invention. FIG. 5 is a diagram illustrating a configuration of a positioning stage including a piezoelectric actuator. FIG. 6 is a diagram showing a block configuration of a conventional positioning stage. It is a figure which shows a mode that the power supply waveform for a drive of the piezoelectric actuator of a precision positioning stage changes with control parameters.

Explanation of symbols

1 Piezoelectric actuator (piezo element)
2 Substrate 3 Stage 4 Capacitance type position detection sensor probe 5 Sensor holder 10 Positioning controller 10a PID calculation unit 10b Communication unit 10c PID constant adjustment unit (gain / offset adjustment unit)
11 Host computer 12 Sensor amplifier 13 Piezo amplifier

Claims (3)

In a precision positioning device composed of a positioning stage equipped with a piezoelectric actuator and a capacitance type position detection sensor,
A precision positioning stage device characterized in that P component, I component, and D component of the control parameters of the positioning stage can be individually adjusted. The individual adjustment of the P component, the I component, and the D component of the control parameter of the positioning stage is performed by an adjustment knob that can be adjusted by a user on a panel portion of the precision positioning device. Precision positioning stage device. The method for adjusting a control parameter of a precision positioning stage apparatus according to claim 1 or 2, wherein the adjustment of the control parameter is executed in accordance with a change in a load mounted on the positioning stage.