Two-axis inclinometer.

0001The invention relates to a biaxial inclinometer according to the preamble of claim 1.

0002Such inclinometers are used, for example, in geodesy to level geodetic measuring instruments. In such inclinometers, an element is provided which changes its position depending on the force of gravity. A measurement mark is mapped onto a positionally stable receiver via this element. A resulting deviation in position from a previously adjusted zero point is a measure of the inclination of the device.

0003Such an inclinometer is known from EP 0 161 207 B1. With slit lighting, a light beam is projected onto a combined glass-liquid prism via a mirror. The prism has a container filled with silicone oil, the inclination being determined by reflection on the liquid horizon and projection of the beam onto a light-sensitive array. With the slit illumination described and shown here, only a uniaxial direction of inclination can be determined with a limited measuring range. In the case of geodetic instruments, in particular, biaxial inclination measurements are required.

0004It is an object of the present invention to develop an inclinometer in such a way that two-axis measurements are made possible with high measuring accuracy and a large measuring range.

0005According to the invention, this object is achieved by the characterizing features of patent claim 1. Advantageous further developments are the subject of the dependent claims.

0006The invention is illustrated in exemplary embodiments and is explained in more detail with reference to the schematic drawings. Show it:<dl id="dl0001"><dt>1</dt><dd>a measuring arrangement with liquid prism in transmitted light,</dd><dt>2</dt><dd>a carrier with a geometric figure designed as a herringbone pattern,</dd><dt>3</dt><dd>a linear array with a projected angle of the geometric figure,</dd><dt>4</dt><dd>a measuring arrangement with liquid prism and beam splitter,</dd><dt>5</dt><dd>a measuring arrangement with a liquid prism and total reflection on the liquid horizon,</dd><dt>6</dt><dd>a measuring arrangement with a thread pendulum,</dd><dt>7</dt><dd>a carrier with a geometric figure designed as a diamond pattern,</dd><dt>8</dt><dd>a carrier with a geometrical figure designed as a meander pattern,</dd><dt>9</dt><dd>a carrier with a geometric figure from broken individual angles,</dd><dt>10</dt><dd>an inclined measuring arrangement with liquid prism in transmitted light.</dd></dl>

0007FIG. 1 shows an arrangement for a biaxial inclinometer with a light source 2, from which an illuminating beam 10 is imaged through a carrier 3 and a liquid prism 1. Optics 4 and 5 are arranged in the beam path. The liquid prism 1 has a liquid 6 in a container 7, which preferably consists of transparent silicone oil. The container 7 is closed by a transparent end plate 11. With the two optics 4, 5, a pattern 12; 17; 18 mapped onto a linear array 8 via the liquid 6, the illuminating beam 10 running parallel in the area of ​​the liquid 6. The arrangement described here can be arranged both in its own housing and as a component in a geodetic measuring instrument.

0008In this embodiment, the illumination beam 10 is deflected in the X and Y directions by refraction on the inclined liquid horizon 9, the liquid 6 behaving like an optical wedge.

0009FIG. 2 shows the carrier 3 with a herringbone pattern 12 arranged thereon from individual angles 13, which are arranged on the carrier 3 in different line widths and at an irregular distance from one another. This coded arrangement achieves a larger measuring range for the inclination measurement. The evaluation of a two-axis inclination measurement with a 90 ° angle is explained in more detail with reference to FIG. 3.

0010FIG. 3 shows the linear array 8 with a single projected angle 13 of the geometric figure. The two legs 15, 16 of the angle 13 cut the array 8 at a point A₁, A₂.

0011As a normal position, ie there is no inclination for X and Y, the tip of the angle 13 was adjusted to the coordinates X₀ and Y₀ and an XY coordinate system was calculated.

0012An XY inclination is determined from the positional deviation of the tip of the angle 13 using the formulas listed below:<maths id="math0001" num=""><img file="EP0507102A2_D0001.tif" /></maths>

0013In order to evaluate an inclination in the Y direction, the angle 13 on the array 8 shifts along the Y axis and thus the tip of the angle 13 parallel to the array 8. This shift is calculated from the amount of the distance Y_s - Y₀ determined.

0014To evaluate an inclination in the X direction, the angle 13 shifts parallel to the array 8 along the X axis and thus the tip of the angle 13 perpendicular to the array 8. This shift is calculated from the amount of the distance X_s - X₀ determined.

0015With an overlapping movement, ie an inclination in the X and Y directions, the amounts of the two resulting displacements on the array 8 can be determined separately.

0016To simplify the calculation, the angle 13 can be 90 ° (ctg 45 ° = 1). However, the measurement sensitivity can also be changed by the choice of the angle. From the above formulas it is clear that with an angle α> 45 ° the sensitivity to an XY shift is greater than with α <45 °. By using a geometric figure, as has already been described for example in FIG. 2, the measuring range is expanded and several measurements can be carried out simultaneously for error compensation. Due to the different line width and / or the different spacing of the individual angles 13 from one another, each individual angle 13 can be clearly identified on the basis of this coding and evaluated in a computer unit (not shown).

0017FIG. 4 shows a further exemplary embodiment with a divider prism 14. The beam 10 is deflected via this divider prism 14 and broken on the liquid horizon 9. The image with the geometric figure is reflected on the mirror 21. The reflected image is imaged on the array 8 via the prism 14.

0018FIG. 5 shows an exemplary embodiment with a combined glass-liquid prism 1, which is characterized in that the incident illuminating beam 10 is reflected on the liquid horizon 9 in the case of oblique illumination and a high deflection of the illuminating beam 10 is achieved therefrom even with slight XY inclinations leaves.

0019FIG. 6 shows an embodiment of the arrangement with a thread pendulum 19, on which the carrier 3 with the geometric structure is arranged. The carrier 3 is illuminated with a light source 2 and the image is projected onto the linear array 8 arranged under the carrier 3. If the distance between the carrier 3 and the array 8 is chosen to be as small as possible in this embodiment, the use of additional optics can be dispensed with.

0020FIG. 7 shows the carrier 3 with a diamond pattern 18 arranged thereon from individual angles 13. Analogously to the exemplary embodiment in FIG. 2, the individual angles 13 can also be embodied here in different line widths.

0021FIG. 8 shows the carrier 3 with a meandering pattern 19 arranged thereon from individual angles 13 strung together. In this embodiment, the individual angles 13 can be provided on the carrier 3 in different line widths and / or at different distances from one another.

0022FIG. 9 shows a geometrical figure with broken individual angles. These angles 22 do not restrict the function of the geometric figure, but only limit the maximum measuring range in the X or Y direction.

002310 shows, analogously to FIG. 1, an inclined measuring arrangement in transmitted light illumination. The liquid horizon 9 aligns itself under the action of gravity with respect to the actual horizon 20 and, together with the cover glass 11, forms an optical wedge on which the parallel illuminating beam 10 is broken. The geometrical figure is depicted on the linear array 8 via the optics 5.

0024The invention is not limited to geodetic measuring instruments, but can be used anywhere as a separate device or in combination with another instrument where XY inclinations are to be recorded.

Reference list

0025<dl id="dl0002"><dt>1 -</dt><dd>Liquid prism</dd><dt>2 -</dt><dd>Light source</dd><dt>3 -</dt><dd>carrier</dd><dt>4 -</dt><dd>optics</dd><dt>5 -</dt><dd>optics</dd><dt>6 -</dt><dd>liquid</dd><dt>7 -</dt><dd>container</dd><dt>8 -</dt><dd>Linear array</dd><dt>9 -</dt><dd>Liquid horizon</dd><dt>10 -</dt><dd>Illuminating beams</dd><dt>11 -</dt><dd>End plate</dd><dt>12 -</dt><dd>Herringbone</dd><dt>13 -</dt><dd>angle</dd><dt>14 -</dt><dd>Divider prism</dd><dt>15;16 -</dt><dd>Thigh of 13</dd><dt>17 -</dt><dd>Meander pattern</dd><dt>18 -</dt><dd>Diamond pattern</dd><dt>19 -</dt><dd>Thread pendulum</dd><dt>20 -</dt><dd>horizon</dd><dt>21 -</dt><dd>mirror</dd><dt>22 -</dt><dd>broken angle</dd></dl>