JPH0580601B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a tilt angle detector that electrically measures tilts around a plurality of coordinate axes simultaneously.

[Prior art and its problems]

Conventional tilt angle detectors are those that use the movement of liquid bubbles 10 as shown in Fig. 7 (Japanese Patent Publication No. 48-42511), and those that use mechanical balance with a weight 11 as shown in Fig. 8. (Japanese Patent Application Laid-Open No. 1983-66870)
These methods all detect inclinations in one direction, and cannot measure inclinations around multiple coordinate axes at the same time. If a measurement is forced, a plurality of similar devices are required, which has the disadvantage of increasing the number of parts, increasing the size, and increasing the cost.

[Purpose of the invention]

This invention eliminates the above drawbacks by attaching a liquid level detection line to a tilt angle detector filled with a conductive fluid, detecting changes in the liquid level as changes in resistance between the liquid level detection lines, and detecting this as a change in resistance between the liquid level detection lines. The object of the present invention is to provide a tilt angle detector that can electrically measure the tilt around each coordinate axis in an arbitrary coordinate system.

[Summary of the invention]

The present invention provides an inclination angle detector comprising a container filled with a conductive fluid and inclined with respect to the inclination of an object to be measured, and at least three liquid level detection lines for detecting the liquid level of the conductive fluid. be.

〔Effect of the invention〕

According to the present invention, it is possible to simultaneously measure the inclination around each coordinate axis in an arbitrary coordinate system with a simple structure,
The number of parts can be reduced, the size can be reduced, and costs can be reduced.

[Embodiments of the invention]

Embodiments of this invention will be described using FIGS. 1 to 6.

FIG. 1 shows a tilt angle detector, in which a liquid level detection line 2 is embedded in a case 1, and a conductive fluid 3 such as mercury is sealed therein. However, case 1 must be a non-conductor or must be completely insulated from the liquid level detection line.

The resistance per unit length of the liquid level detection line was sufficiently large compared to that of the conductive fluid, and in this example, a coiled line was used. Thereby, it is possible to detect a large resistance change even in response to a liquid level change due to a slight inclination. The liquid level detection lines are arranged on the sides of the cubic case 1, that is, in the three orthogonal axes, and the amount of the conductive fluid sealed is such that the three liquid level detection lines can simultaneously detect the liquid level.

Figures 2 to 5 are diagrams explaining the tilt angle measurement method using the tilt angle detector of this embodiment. Figure 2 is a diagram explaining the measurement principle, and Figure 3 is a diagram for the reference position. , and FIG. 4 shows the case where it is tilted from the reference position. In FIG. 2, three liquid level detection lines are in contact with the conductive fluid F at distances a', b', and c' from the end point 0. If it is at the reference point as shown in Figure 3,
a'=b'=c', and when tilted from the reference point as shown in FIG. 4, a'≠b'≠c'.

Considering the state shown in FIG. 2, the liquid level L is at positions a', b', and c' from the terminal end O, respectively. In this part, that is, the part where the liquid level detection line M is immersed in the conductive fluid, when a current is applied, the conductive fluid has a lower resistance than the liquid level detection line, and no current flows through the liquid level detection line. Utilizing this, the length from the terminal end O to the liquid level is electrically detected, thereby measuring the inclination angle around each coordinate axis in the coordinates X-Y-Z fixed in space.

Let the resistance per unit length of the liquid level detection line be ρ,
Also, for simplicity, assuming that the resistance of the conductive fluid is O, the resistance RA between the liquid level detection lines, OA, OB, and OC,
RB and RC are expressed by formulas (1) to (3).

RA=(a−a′)ρ (1) RB=(b−b′)ρ (2) RC=(c−c′)ρ (3) From this, the lengths of a′, b′, and c′ are It can be found from equations (4), (5), and (6).

a′=a−RA/ρ (4) b′=b−RA/ρ (5) c′=c−RC/ρ (6) Once the lengths of a′, b′, and c′ are found, the slope The normal component of the liquid surface to the coordinate system X'-Y'-Z' fixed to the angle detector is determined, and this and the normal component of the liquid surface to the coordinate system X-Y-Z fixed in space. From the relationship, the inclination of the inclination angle detector around each coordinate axis of coordinates X-Y-Z can be determined.

The inclinations in the three directions shown in Figure 5 and a'/a, b'/
The relationship between b, c'/c is as shown in equations (7), (8), and (9), and b'/b・c'/c=cosφsinθcosψ+sinφsinψ(
7) a′／a・c′／c＝sinφsinθcosψ−cosφsinψ(
8) a'/a・b'/b=cosθcosψ From this, φ, θ, and ψ can be found.

FIG. 6 shows a circuit for converting the change in the resistance value of the liquid level detection line into voltage and inputting it into the computer.
A constant voltage is applied to each of the three liquid level detection lines, and as the resistance value of the liquid level detection lines changes, the voltage of the liquid level detection lines changes. The angle of inclination in three directions is calculated using a calculator based on this input to the converter.

Note that the present invention is not limited to the above embodiments. For example, in the embodiment described above, the case 1 has a cubic shape, but it may have a spherical shape or any other shape. Further, the shape of the liquid level detection line is not limited to a coil shape, but can take various shapes. Further, the mounting direction of the liquid level detection line is not limited to the three mutually orthogonal directions, but may be around each coordinate axis in any coordinate system that is not linearly dependent.

[Brief explanation of drawings]

FIG. 1 is a fragmented cross-sectional view of the tilt angle detector, FIGS. 2 to 5 are diagrams explaining the method of measuring the tilt angle,
FIG. 6 is a sectional view showing a liquid level detection circuit used in the present invention, and FIGS. 7 and 8 are sectional views showing a conventional detector. 1...Case, 2...Liquid level detection line, 3...Mercury, 4...Lead wire, 5...Switch, 6...
A/D converter, 7...CPU (computer).

Claims (1)

[Claims] 1. A container that tilts in accordance with the tilt of the object to be measured;
A conductive fluid sealed in this container, a plurality of liquid level detection lines arranged so as to be in contact with the liquid surface of this conductive fluid, and the said conductivity with respect to a coordinate system consisting of these plurality of liquid level detection lines. means for calculating the inclination angle of the object to be measured around each coordinate axis in the arbitrary coordinate system from the relationship between the normal direction component of the liquid level of the fluid and the normal direction component with respect to another arbitrary coordinate system; A tilt angle detector comprising: 2. The tilt angle detector according to claim 1, wherein the conductive fluid is mercury. 3. The tilt angle detector according to claim 1, wherein the liquid level detection line is formed in a coil shape.