JPH07319543A - Precise positioning device - Google Patents

Abstract

PURPOSE:To stabilize an operation at the time of high-resolution positioning by eliminating load wiring not to be ignored at the time of precise positioning by controlling a driving circuit with no contact. CONSTITUTION:An ultrasonic linear motor is integrated inside a fixed part 1 and a part 2 to be driven is driven in the direction of an arrow. Then, light receiving parts 4 and 5 of phototransistors are fitted on the side face of the fixed part 1 and connected to the driving circuit inside the fixed part 1. In this case, the structure/operation of this ultrasonic linear motor is similar to the conventional technique. Further, two LEDs 6 and 7 are fitted at positions facing to the light receiving parts 4 and 5 on a controller 3, the optical signal of the LED 6 is made incident to the light receiving part 4 and the optical signal of the LED 7 is made incident to the light receiving part 5 respectively. At such a time, however, optical filters with different passing wavelengths are provided so that both the signals can not be mixed. Thus, since the driving circuit is controlled with no contact, the load due to wiring not to be ignored at the time of precise positioning is eliminated.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a precision positioning device having a high resolution of about several μm or more.

[0002]

2. Description of the Related Art In recent years, there has been a need for a positioning device with high resolution and high accuracy in various industrial equipment fields, and various devices have been devised to realize this. An ultrasonic motor has attracted attention as one of the actuators that realizes high resolution, and attempts have been made to apply it to a positioning device.

As an example of an ultrasonic motor which realizes such a high resolution, Japanese Patent Application No.
No. 321096 is available. According to this, as shown in FIG. 8, two laminated piezoelectric elements 10 are provided on the elastic body 100.
1, 102 holding members 103, 104 in the stacking direction,
The elastic body 10 is sandwiched and fixed by 105.
A plurality of sliding members 106 and 107 are bonded to the lower surface of 0 to form an ultrasonic transducer.

Then, as shown in FIG. 9, this ultrasonic transducer is provided with a linear guide 108, a guide rail 109, a holding frame 110, a screw 111, a pressing force adjusting screw 112, and a spring 11.
3. The vibrator holding member 114 holds the sliding member 10 on the sliding plate 115 while holding it so that it can move linearly in the left-right direction.
6 and 107 are pressed so as to make frictional contact with each other to form an ultrasonic linear motor.

When the ultrasonic linear motor having the above-mentioned structure is driven, the dimensions of the ultrasonic vibrator are appropriately adjusted and an AC voltage is applied to the laminated piezoelectric elements 101 and 102, as shown in FIG. The longitudinal resonance vibration and the bending resonance vibration shown in FIG. 11 occur at the same time. Two laminated piezoelectric elements 1
When the phase difference between the voltages applied to 01 and 102 is appropriately adjusted, the longitudinal vibration and the bending vibration are combined to generate elliptical vibration at the antinode position of the bending vibration. As a result, a driving force is generated between the sliding members 106 and 107 fixed at the position where the elliptical vibration occurs and the sliding plate 115 that is in contact with the sliding members 106 and 107.

More specifically, the voltage applied to the laminated piezoelectric elements 101 and 102 is 10 Vp-p, which is a frequency that matches the resonance frequency of longitudinal vibration and bending vibration of the ultrasonic vibrator.
The alternating voltage is of the order of magnitude, and the phase difference between the two alternating voltages is
One applied to one laminated piezoelectric element, the other +
The ultrasonic linear motor is driven by setting it to 90 degrees,
On the other hand, by setting this phase difference to -90 degrees, the moving direction of the ultrasonic linear motor is reversed.

[0007]

However, when a multi-axis precision positioning device is constructed by stacking a plurality of electric stages using the above-mentioned ultrasonic linear motor, that is, as shown in FIG. 7A, for example, an X-axis stage. When the Y-axis stage 117 is superposed on the 116 to form a two-axis configuration, a connecting electric wire 118 for the Y-axis motor or encoder and its driving device is required as shown in FIG. A bending force due to bending and a frictional force with which an electric wire comes into contact with a surrounding object impose a burden on the X-axis movement, so that the driven body cannot be smoothly driven in the X-axis direction, and there is a problem that the positioning resolution deteriorates.

The present invention has been made in view of the above problems, and an object of the present invention is to provide a high-resolution precision positioning device which can eliminate the burden of wiring and which has a simple configuration of a drive circuit.

[0009]

In order to achieve the above object, in the precision positioning apparatus of the present invention according to claim 1, a driving force generating device and a driven body which is driven by the driving force generating device and relatively moves. A drive circuit that is fixed to the same housing as the drive force generation device and supplies drive energy to the drive force generation device. The drive circuit is wirelessly or optically transmitted from a control device separate from the positioning device body. Controlled by communication without contact.

In this case, as described in claim 2, it is preferable to use an ultrasonic motor as the driving force generating device.

[0011]

In the precision positioning device according to the first aspect of the present invention, since the drive circuit is controlled in a non-contact manner, the load due to the wiring that cannot be ignored during precision positioning is eliminated.

Further, in the precision positioning device according to the second aspect, by using an ultrasonic motor having high resolution as the driving force generating device, higher resolution and higher precision positioning is realized.

[0013]

Embodiment 1 An embodiment of a precision positioning device according to the present invention will be described below with reference to the accompanying drawings. First, a first embodiment of the present invention will be described. FIG. 1 is a schematic view showing a precision positioning device.

In the figure, an ultrasonic linear motor (not shown) is incorporated in the fixed portion 1 to drive the driven portion 2 in the direction of the arrow. The light receiving portions 4 and 5 of the phototransistor are attached to the side surfaces of the fixed portion 1 and are connected to the drive circuit inside the fixed portion 1.
The structure and operation of the ultrasonic linear motor are the same as those of the conventional technology. Further, although a single-axis stage is shown in the drawing, a plurality of these are actually combined to form a multi-axis stage.

Two LEDs 6 and 7 are attached to the control device 3 at positions facing the light receiving portions 4 and 5, respectively.
Of the light signal of the LED 7 and the light signal of the LED 7 of the LED 7, respectively. At this time, an optical filter having different passing wavelengths is provided so that the signals of both are not confused.

Next, the drive circuit inside the fixed portion 1 will be described with reference to FIG. The oscillator 7 generates a frequency four times as high as the drive frequency of the ultrasonic motor, and the oscillation output is connected to the clock input terminal CK of the drive pattern generator 10 via the AND gate 8. To the other input of the AND gate 8, the signal of the phototransistor 4 inverted by the inverter 11 is input. The signal of the phototransistor 5 is the up / down input terminal U / of the drive pattern generator 10.
Connected to D. The drive pattern generator 10 is configured using a commercially available stepping motor drive IC (for example, PMM8713 manufactured by Sanyo Denki Co., Ltd.).

The output A of the starting pattern generator 10 alternately turns ON / OFF the two FETs 12a and 13a, and alternately applies a positive voltage and 0V to the piezoelectric element 15a via the inductor 14a. Similarly, the output B of the drive pattern generator 10 turns on / off the FETs 12b and 13b alternately.
Then, a positive voltage and 0 V are alternately applied to the piezoelectric element 15b via the inductor 14b. All circuits above are battery 1
Works with 6. In the experiment, it was confirmed that the voltage of the battery 16 was several V and the ultrasonic motor generated the necessary driving force.

Next, the operation of the precision positioning device of this embodiment having the above-mentioned structure will be described. In the present embodiment, as will be described below, when the control device 3 lights the LED 6, an AC voltage is applied to the ultrasonic motor to drive the driven body 2.
Moves. When the LED 7 is turned ON / OFF, the moving direction of the driven body 2 is switched.

Now, when the LED 6 is off,
The output of the phototransistor 4 is pulled up to the H level, and the inverted L level of the output 11 is input to one of the AND gates 9. Therefore, the drive pattern generator 1
No clock is input to the 0 CK terminal. For this reason,
No drive signal is supplied to the piezoelectric elements 15a and 15b, and the ultrasonic motor is in a stopped state.

When the LED 6 is turned on, the phototransistor 4 is turned on and the clock of the oscillator 8 is ANDed.
The signal is input to the CK terminal via the gate 9. At this time, the drive pattern generator 10 operates as shown in FIG. In other words, when a clock is applied to the CK terminal, the output terminals A and B have a phase difference of 90 degrees from each other and a quarter of the clock.
A frequency signal appears. When the H / L level of the signal applied to the U / D terminal is inverted, the phases of the output terminals A and B are inverted. The outputs of the terminals A and B are current-amplified by the FETs 12 and 13, and the inductor 14 removes the harmonics of the rectangular wave to drive the piezoelectric element 15.

As described above, according to this embodiment, it is possible to eliminate the wiring of the positioning device with a simple structure. This eliminates the burden of wiring when the precision positioning device has a multi-axis structure, and enables smooth and highly accurate positioning.

The precision positioning device of the present embodiment has a direct purpose of preventing deterioration of the positioning accuracy due to a disturbance such as wiring load, and is premised on positioning in an open loop without feedback. This does not prevent the closed loop control by using the non-contact displacement gauge 17 as shown in FIG. 4A or the CCD camera 18 and the image processing device 19 as shown in FIG. 4B. Absent. This is because the non-contact control can produce various technical effects by itself.

[0023]

Second Embodiment Next, a second embodiment of the present invention will be described. Figure 5
FIG. 3 is a schematic view showing a precision positioning device. In this embodiment, the position of the driven portion 32 is detected by the encoder 33,
Feedback was applied to the controller 34.

In the figure, an ultrasonic linear motor (not shown) is incorporated in the fixed portion 31 to drive the driven portion 32 in the arrow direction. The position of the driven portion 32 is detected by the linear encoder 33 and transmitted to the drive circuit inside the fixed portion 31. Fixed part 3
Light receiving parts 39 and 40 of the phototransistor and LEDs 41 and 42 are attached to the side surface of the No. 1 and connected to a drive circuit inside the fixing part 31.

The controller 34 has two LEDs 35, 3
6 is attached at a position facing the phototransistors 39 and 40, and the optical signal of the LED 35 is the phototransistor 3
9, the optical signals of the LEDs 36 enter the phototransistors 40, respectively. Two phototransistors 37 and 38 are also attached to the control device 34 at positions facing the LEDs 41 and 42, and the optical signal of the LED 41 enters the phototransistor 37 and the optical signal of the LED 42 enters the phototransistor 38, respectively. At this time, optical filters having different passing wavelengths are provided so that these signals are not confused.

Next, the drive circuit inside the fixed portion 31 will be described with reference to FIG. The drive circuit is composed of a power unit and a sensor unit. The power unit has the same configuration as that of the first embodiment, and the driver 43 drives the motor 44 according to the optical signals received by the phototransistors 39 and 40. The sensor unit converts the displacement of the driven unit 32 detected by the linear encoder 33 into an UP / DOWN pulse signal by the encoder circuit 45, and turns on either the UP pulse LED 41 or the DOWN pulse LED 42. It should be noted that these circuits are operated by a battery built in the fixing portion 21.

Next, referring to FIG. 6A, the internal structure of the controller 34 will be described. The control device 34 receives a command pulse from the operation unit 49 that commands the displacement amount of the driven unit 32, and LE.
The deviation counter 48 counts the difference between the optical signal corresponding to the amount of displacement from D41 and 42 and the signal of the phototransistors 37 and 38 which received the optical signal, and inputs it to the microcomputer 46. The output of the microcomputer 46 is connected to the LED driver 47 and turns on the LEDs 35 and 36.

Next, the operation of the precision positioning apparatus of this embodiment having the above-mentioned structure will be described.

A deviation occurs in the deviation counter 48 by operating the operation section 49, and the deviation is read by the microcomputer 46. The microcomputer 46 calculates the drive amount of the motor 44 by the program, and lights the LEDs 35 and 36 according to the result.

The optical signals of the LEDs 35 and 36 are received by the phototransistors 39 and 40, and drive the motor 44 via the motor driver 43. The displacement of the driven portion 2 due to this is detected by the linear encoder 33, and the encoder circuit 45 turns on the LEDs 41 and 42 a number of times corresponding to the displacement amount.

The optical signals of the LEDs 41 and 42 are received by the phototransistors 37 and 38, and the deviation of the deviation counter 48 is subtracted by this signal.

As described above, the deviation of the deviation counter 48 is controlled to be zero, and the positioning is performed by the closed loop control.

According to this embodiment, it is possible to eliminate the wiring of the motor and the encoder when the positioning for the closed loop control is performed. This eliminates the burden of wiring when the precision positioning device has a multi-axis structure, and enables smooth and highly accurate positioning.

[0034]

As described above, according to the precision positioning device of the present invention, the following effects can be obtained.

In the precision positioning device according to the first aspect, since the drive circuit is controlled in a non-contact manner, it is possible to eliminate a load due to wiring that cannot be ignored during precision positioning, so that the operation during high resolution positioning is stable.

In the precision positioning device according to the second aspect, by using an ultrasonic motor having essentially high resolution as the driving force generating device, it is possible to realize highly accurate positioning with higher resolution.

[Brief description of drawings]

FIG. 1 is a schematic diagram showing a precision positioning device according to a first embodiment.

FIG. 2 is a circuit diagram showing a drive circuit of the precision positioning device according to the first embodiment.

FIG. 3 is a timing chart showing the operation of the drive circuit of the precision positioning device of the first embodiment.

FIG. 4 is a diagram illustrating a modified example of the first embodiment.

FIG. 5 is a schematic diagram showing a precision positioning device according to a second embodiment.

FIG. 6 is a block diagram showing a drive circuit and a control circuit of the precision positioning device according to the second embodiment.

FIG. 7 is a diagram illustrating a problem of the conventional technique.

FIG. 8 is a diagram illustrating a conventional technique.

FIG. 9 is a diagram illustrating a conventional technique.

FIG. 10 is a diagram illustrating a conventional technique.

FIG. 11 is a diagram illustrating a conventional technique.

[Explanation of symbols]

 1 Fixed body 2 Driven body 3 Control device 4,5 Light receiving part 6,7 LED

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Yoshihisa Taniguchi 2-43-2 Hatagaya, Shibuya-ku, Tokyo Inside Olympus Optical Co., Ltd. (72) Inventor Kazuhiro Awai 2-43-2 Hatagaya, Shibuya-ku, Tokyo Olympus Optical Industry Co., Ltd.

Claims (2)

[Claims] 1. A driving force generator, a driven body which is driven by the driving force generator and moves relatively, and is fixed to the same housing as the driving force generator and supplies driving energy to the driving force generator. And a drive circuit for controlling the drive circuit, and the drive circuit is controlled in a contactless manner by a control device separate from the positioning device body by wireless or optical communication. 2. The precision positioning device according to claim 1, wherein an ultrasonic motor is used as the driving force generator.