JPH03138512A - Surveying machine - Google Patents

Abstract

PURPOSE:To improve the measurement accuracy by applying an AC voltage to a 1st piezoelectric body and vibrating it, and resonating an elastic body in primary mode of longitudinal vibration and exciting a standing wave. CONSTITUTION:When the 1st piezoelectric body 22 is applied with the AC voltage to vibrate, the elastic body 21 resonates in the primary mode of longitudinal vibration to excite the standing wave. Then, when 2nd piezoelectric bodies 23a and 23b are applied with an AC voltage to vibrate, the elastic body 21 vibrates in secondary mode of bending vibration to excite a standing wave. Namely, positions of fixation by fixing bolts 24a and 24b are nodes of the standing waves. At this time, the amplitudes and phases of the voltages applied to the 1st piezoelectric body 22 and 2nd piezoelectric bodies 23a and 23b are adjusted to put the elastic body 21 in nearly elliptic vibration in an optional shape.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a surveying instrument whose drive source is a piezoelectric actuator that obtains mechanical output using piezoelectric phenomena.

[Prior Art] A conventional example of a surveying instrument used for surveying various types of construction work is proposed in Japanese Patent Laid-Open No. 61-283811.

This is shown in FIG.

This surveying instrument A has two control rotary electromagnetic motors B and C attached to the side of the main body through adapters D to knobs E and F for fine adjustment in the vertical and horizontal directions, respectively.

As the target moves, the control motors B and C are driven by remote control or a drive command from a computer (not shown), and the horizontal or vertical fine adjustment knobs E and F of the surveying instrument A are rotated to adjust the telescope. This structure allows the reference direction of G to follow the movement of the measurement point.

[Problems to be Solved by the Invention] However, conventional surveying instruments measure length by moving a laser beam in horizontal and vertical directions, and use a rotary electromagnetic motor as a drive source, so the low frequency of the motor There was a problem in that vibrations were transmitted to the laser, reducing measurement accuracy.

Furthermore, since a power conversion mechanism is used to obtain linear motion, there is a problem of poor drive efficiency and an increase in the size of the device.

The present invention has been made to solve the above-mentioned problems, and aims to improve measurement accuracy by using a piezoelectric actuator as a drive source.

Furthermore, since no power conversion mechanism is used, the present invention aims to improve drive efficiency and make the device smaller and lighter.

[Means for solving the problem] In order to achieve this objective, the surveying instrument of the present invention has the following features:
A board that is a board on which a surveying instrument is placed and has a horizontality adjustment function, a turntable that is rotatably placed on the board, and a board that is placed on the turntable and that is vertical in the horizontal direction or vertical direction. A surveying instrument equipped with a movable or rotationally movable telescope and a laser firing tube is configured to use a piezoelectric actuator as a drive source.

[Operation] In the surveying instrument of the present invention having the above configuration, when an AC electric signal is applied to a piezoelectric actuator that obtains a mechanical output using a piezoelectric phenomenon, a substantially elliptical vibration of minute amplitude is excited in a predetermined part of the piezoelectric actuator. Ru. When a driven object, such as a telescope or a laser tube, is directly pressed onto the piezoelectric actuator at a predetermined pressure, the telescope or laser tube is driven in a predetermined direction by receiving a driving force caused by the frictional force.

[Example] Hereinafter, an example embodying the present invention will be described with reference to the drawings.

The piezoelectric actuator used in the present invention is disclosed in, for example, Japanese Patent Application No.
An ultrasonic transducer including a mechanical resonator as proposed in the specification and drawings attached to application No. 46866 may be used.

An example of the configuration will be described below with reference to FIG.

In the ultrasonic transducer 11 of this embodiment, a first piezoelectric body 22 for exciting bending vibration in the elastic body 21 is attached to the upper surface of an elastic body 21 having a rectangular flat plate shape. The elastic body 21
A second piezoelectric body 23a and a second piezoelectric body 23a for exciting longitudinal vibration in the elastic body 21 are provided on a side surface substantially orthogonal to the mounting surface.
3b is installed.

The longitudinal center of the elastic body 21 is fixed by fixing bolts 24a and 24b for fixing the elastic body 21. The other ends of the fixing bolts 24a and 24b are
It is fixed to bases 25a and 25b.

An electrode 26 is provided on the upper surface of the first piezoelectric body 22 . Further, electrodes 27a and 27b are installed on the upper surfaces of the second piezoelectric bodies 23a and 23b. The elastic body 21 itself also serves as a ground electrode, and is installed on the bases 25a and 25b via the fixing bolts 24a and 24b.

Furthermore, the elastic body 21 bends in a secondary mode at both free ends in the thickness direction at a predetermined frequency f, and longitudinally vibrates in a primary mode in the free end at both ends in the length direction at the same frequency f. The shape and dimensions have been adjusted.

Generally, the resonant frequency of longitudinal vibration propagating in an elastic body depends on the length of the elastic body. Further, the resonance frequency of bending vibration in the thickness direction of the elastic body depends on the length and thickness. Therefore, it is easy to design the elastic body 21 as described above, so the details thereof will be omitted.

The operation of the ultrasonic transducer 11 configured as above will be explained below.

First, when an alternating current voltage of frequency f is applied to the first piezoelectric body 22 to cause it to vibrate, the elastic body 21 resonates in the first mode of longitudinal vibration, and a standing wave is excited.

Next, when an AC voltage of frequency f is applied to the second piezoelectric bodies 23a and 23b to cause them to vibrate, the elastic body 21 is
It vibrates in the following mode and a standing wave is excited. In other words, the positions fixed by the fixing bolts 24a and 24b are the nodes of each standing wave.

At this time, the first piezoelectric body 22 and the second piezoelectric bodies 23a and 2
By adjusting the amplitude and phase of the voltage applied to the elastic body 3b, the elastic body 21 has the ability to generate substantially elliptical vibration of an arbitrary shape with a vehicle force <'oJ.

Further, in the above embodiment, the explanation was given using the first-order mode of longitudinal vibration and the second-order mode of bending vibration, but the invention is not limited to this, and various vibration modes such as longitudinal vibration, bending vibration, shear vibration, and torsional vibration can be used. can be considered, and higher-order modes may also be used.

FIG. 2 shows the configuration of a surveying instrument that suitably utilizes the above-mentioned ultrasonic transducer 11.

The surveying instrument 31 has a horizontal first turntable 33 mounted on a base plate 32, and a vertical shaft 34 that can move in the vertical direction is attached to the first turntable 33. A vertical second turntable 35 is attached to the shaft 34.
is attached to the second turntable 35, and a laser emitting tube 36 and a telescope 37 are fixed to the second turntable 35.

Next, the ultrasonic transducer 11. The crimping methods a to 11c will be explained.

FIG. 4 shows a portion where the ultrasonic transducer 11a is pressed onto the vertical shaft 34. The ultrasonic transducer 1 1, a is case 3
8 and is supported by the first support part 39. The vertical shaft 34 is supported by linear bearings 40a to 40d, and the ultrasonic transducer 1.1a is attached to the vertical shaft 34.
is pressed by a rubber roller 41.

FIG. 5 shows a portion where the ultrasonic transducer 11b is crimped onto the first turntable 33. As shown in FIG. The ultrasonic transducer 11b
is connected to the first turntable 3 by the second support part 42.
It is crimped on the side of 3.

Further, the second turntable 35 and the ultrasonic vibrator 11
The positional relationship with c is also similar.

Next, the ultrasonic transducer 1 1 crimped onto the vertical shaft 34
, a will be taken as an example to explain its operation. When an alternating current voltage is applied to the ultrasonic transducer 11a, approximately elliptical vibration with a very small vibration amplitude of several micrometers to several tens of micrometers is excited. As a result, the vertical shaft 34 is driven in a predetermined direction by receiving a driving force caused by the frictional force between the ultrasonic transducer 11a and the vertical shaft 34. Therefore, the above-mentioned surveying instrument 31 can directly drive the vertical shaft 34 linearly. As a result, it is possible to realize a compact and lightweight surveying instrument that does not require a power transmission mechanism.

Furthermore, since low frequency vibrations unlike conventional electromagnetic motors do not occur, a surveying instrument with high measurement accuracy can be obtained.

Further, the operating principles of the first turntable and the second turntable are also the same.

Furthermore, the piezoelectric actuator used in the present invention has the following advantages over conventional electromagnetic motors.

1) Since no winding is required and the structure is simple, it can be made smaller and lighter.

2) High energy conversion efficiency can be obtained; for example, the output/volume ratio and output/weight ratio are 10 times or more compared to a DC motor.

3) Excellent responsiveness and position control as it utilizes frictional force.

4) Does not generate magnetic or electrical noise.

In the above embodiment, an ultrasonic vibrator that generates standing wave vibration is used as the piezoelectric actuator, but the present invention is not limited to this, and examples include a laminated piezoelectric actuator, a bimorph piezoelectric actuator, and a traveling wave ultrasonic motor. Various actuators can be considered.

Furthermore, although an example in which the shape of the ultrasonic transducer is a flat plate has been described, the shape is not limited to this, and the shape is rod-like, rectangular, etc.
Various shapes can be considered, such as cylindrical, annular, and disk-like.

In addition, various modifications can be made without departing from the spirit of the present invention.

[Effects of the Invention] As is clear from the detailed description above, according to the present invention, a surveying instrument with high measurement accuracy can be obtained.

Furthermore, a surveying instrument that has high drive efficiency and can be made smaller and lighter can be obtained.

[Brief explanation of the drawing]

Figures 1 to 5 show embodiments embodying the present invention. Figure 1 is a diagram showing the top surface of an ultrasonic transducer used in the present invention, and Figure 2 is a surveying example to which the present invention is applied. 3 is a diagram showing the top surface of the surveying instrument to which the present invention is applied, FIGS. 4 and 5 are diagrams showing the crimping part of the ultrasonic transducer, and FIG. FIG. 1 is a diagram showing an example of a surveying instrument. In the figure, lla to 11c are ultrasonic transducers, 32 is a substrate, and 3
3 is the first turntable, 35 is the second turntable,
36 is a laser launcher, and 37 is a telescope.

Claims (1)

[Claims] 1. A board on which a surveying instrument is placed and which has a horizontality adjustment function; a turntable rotatably placed on the board; and a turntable placed on the turntable. , a surveying instrument equipped with a telescope and a laser firing tube that can move vertically or rotationally in the horizontal direction or in the vertical direction, characterized in that a piezoelectric actuator is used as a drive source. 2. The surveying instrument according to claim 1, wherein the piezoelectric actuator is an ultrasonic vibrator including a mechanical resonator having a vibration portion that performs substantially elliptical vibration.