AT513950A1 - Mounting system for opto-electronic instruments - Google Patents

Abstract

Assembly system for an opto-electronic instrument in a host vehicle, wherein the opto-electronic instrument is connected to an inertial navigation system for detecting at least the orientation of the instrument in space, but possibly also for determining the position thereof in a coordinate system, to a rigid module and the from the opto-electronic instrument, data associated with the data supplied by the inertial navigation system data sets, wherein the module formed from the instrument and the navigation system is connected to the structure of the host vehicle via spring / damping elements and these are designed and arranged so that they form together with the mass of the module, a mechanical low-pass filter which substantially absorbs vibrations of the host vehicle, which are above a cutoff frequency, but transmits low-frequency vibrations to the module, wherein the cut-off frequency is selected so ss transmitted by the spring I attenuation elements, low-frequency movements of the module by the inertial navigation system can be detected by data.

Description

Pat. 0680 • JSIIjCjL Laser Measurement • · t · · · • · · • · ·

Systems

RIEGL

Laser Measurement Systems GmbH. HORN 5

Mounting system for opto-electronic instruments. The invention relates to a mounting system for opto-electronic

Instruments in carrier vehicles, wherein the opto-electronic instrument is connected to an inertial navigation system at least for detecting the orientation of the instrument in space but possibly also for determining the position in a coordinate system to a rigid module and the opto-electronic instrument, such as a Laser range finder or a laser scanner, data collected with the data supplied by the inertial navigation system (IMU) spatial orientation of the instrument are linked to records, with the module formed by the instrument and the navigation system (IMU) with the structure of the

Carrier is connected via spring / damping elements.

The carrier vehicles may be land or rail vehicles, or vessels, or aircraft such as airplanes or helicopters, in which, while they are moving,

Measurements, photographic recordings od. Like. Be made. All these carrier vehicles have in common that they od in these measurements, recordings. Like. Can move around one or more axes. In order to ensure a corresponding assignment to the room to be measured or recorded, it is known that the opto-electronic instrument with 2/30 1

Pat. 0680 .......... JJIEGL Laser Measurement Systems • ················································································· •••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••• can. As a rule, such an instrument is also combined with a navigation system with which its respective position in a superordinate, for example global, coordinate system is determined. As navigation systems of this kind, wheel sensors can generally also be used in rail vehicles and land vehicles, but satellite-supported systems 10 (GNNS eg GPS) have proven to be widely used for all these applications.

Navigation system (IMU) to an integrated IMU / GNNS system are combined. This gives you the exact coordinates for each measuring point in a higher-level coordinate system. 15 The opto-electronic instruments are exposed in use not only to the intended movements of the carrier vehicle but also shocks, shocks, vibrations, etc., which are transmitted from the structure of the carrier vehicle to the instruments. Such instruments typically include shock and vibration sensitive components and therefore must be connected to the structure of the host vehicle with spring / damper elements to protect them.

According to the invention the spring / Dämpfimgselemente are designed and arranged so that they form a mechanical low-pass filter together with the mass of the module, which movements esp. Oscillations of the

Carrier vehicle, which are located above a cutoff frequency substantially absorb low-frequency vibrations but transmitted to the module, wherein the cutoff frequency is chosen so that the transmitted by the spring / damping elements, low-frequency movements of the module 30 from the inertial navigation system (IMU) can be detected by data. 3/30 2

Pat. 0680 .......... J5.II; LR Laser Measurement Systems • ········································································· · · · · · · ·· I · ♦ · ♦ · · · «

In some installations of such instruments these are not mounted directly on the carrier vehicle, but on a arranged on the carrier vehicle stabilized platform. In such a case, 5 according to the invention at least that of the instrument and the

Navigation module formed mounted on the stabilized platform with the interposition of spring-damping elements, wherein the spring / damping elements are designed and arranged so that they form together with the mass of the module a mechanical low-pass filter, which vibrations of the stabilized platform, which over a

Limit frequency are substantially absorbed, but low-frequency vibrations to the module transmits, the cutoff frequency is chosen so that the transmitted by the spring / damping elements, low-frequency movements of the module from the inertial navigation system 15 can be detected in terms of data.

According to a further feature of the invention, the mounting system comprises a two-stage mechanical decoupling, wherein on the one hand, the rigid module is mechanically decoupled from the support structure to not 20 deformations thereof transferred to the module and on the other hand, the spring / damping elements are formed so that they together form the mechanical low-pass filter with the mass of the module and its support structure. 25 For the most commonly used inertial navigation systems (IMU) and

For carrier vehicle / instrument configurations, the cutoff frequency is preferably set at about 25 Hz.

According to a further feature of the invention, the module is movably suspended or braced in all three coordinate directions 30. 4/30 3

Pat. 0680 .......... RIEGL Laser Measurement Systems • ·············································································· • · · · · · · ··· · · ·

Preferably, the spring and damping elements are designed at the individual points of attack on the module, taking into account their position relative to the center of gravity of the module so that both longitudinal and torsional vibrations or deformations are largely damped

According to the invention the spring / Dämpfimgselemente are formed and positioned on the module that based on the center of gravity of the module, the sum of the moments of those forces that are transferable to the module is substantially zero.

In applications where the measurement distance is significantly greater than the dimensions of the instrument module, displacements of the module in longitudinal directions have little effect on the measurement results, while the system is extremely sensitive to rotational movement of the module. To avoid the excitation of such rotational movements or torsional vibrations as much as possible, according to the invention, the spring and damping elements at the individual points of attack on the module, taking into account their position with respect to the center of gravity of the module designed so that torsional vibrations are largely damped.

The spring / damping elements are preferably designed and positioned on the module such that, based on the center of gravity of the module, the sum of the moments of those force components which can be transmitted to the module and which are normal to the optical axis of the optoelectronic instrument is substantially Is zero. By this measure, longitudinal movements are allowed in the direction of the optical axis of the instrument and normal to this, however, an excitation of torsional vibrations is suppressed. 5/30 4

Pat. 0680 .......... RIEGL Laser Measurement Systems • · · · · · · · · · · ········································································· ♦ ··· · ♦ ···· t

In order to avoid interfering with the installation of additional devices such as digital photo or video cameras or navigation devices or their sensors on the module fittings for rigid attachment of these accessories are provided on the module outside. Since the total mass of the module is changed by the installation of such accessories, which has an effect on tuning the mechanical low-pass filter formed from the spring / mass system, it is advantageous to provide the connection pieces on the outside of the module first Kompensationsmassen, which are reduced accordingly during assembly of additional equipment

Further features of the invention will become apparent from the following description of some embodiments and with reference to the drawings. FIG. 1 shows, as an example of an optoelectronic instrument, a laser scanner for airborne applications, partly in section. 2 shows a ready-to-install instrument in an axionometric view, FIGS. 3 and 4 illustrate two different mounting systems for two substantially similar instrument modules.

The laser scanner for "airbome" applications shown in FIG. 1 as an example of an optoelectronic instrument essentially comprises a laser rangefinder 1 according to the pulse transit time method and a downstream beam deflection device 2. In the example shown, the beam deflection device comprises a glass wedge prism 11, which rotates at high speed about the optical axis 7 of the laser rangefinder 1. 6/30 5

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The instrument is mounted on a mounting plate 31 which is connected to four columns 32 with a plate 33 and forms with these a stable and rigid frame. Within this frame 31-33, a laser source 4 is arranged, which mirrors a laser beam in the optical axis 7 of the instrument via a mirror system 5.6. Instead of the mirror system 5, 6 can also be used a flexible optical fiber light guide.

Under the laser Entfemungsmesser a cylinder 8 is provided, which is rotatably mounted in bearings 9 about the optical axis 7 of the laser removal meter 1 and driven by an electric motor 10 at high speed. In this cylinder, the glass wedge prism 11 is mounted, through which the transmitting laser beams are deflected. Upon rotation of the wedge prism 11, these laser beams 12 in their entirety form a beam cone which scans a planar area lying below the laser scanner in a circular arc. The laser beams are generally diffusely reflected from the terrain and the objects, vegetation, etc. present thereon. A small portion of this radiation reaches the laser scanner again, is aligned by the wedge prism 11 parallel to the optical axis 7 and imaged by the receiver optics 14 on the photosensitive cell of the receiver 15. In the receiver 15, the incoming optical pulses are converted into electrical signals. In an evaluation device, not shown, which may also be arranged externally and connected to the laser scanner with a cable, the electrical pulses may be digitized. From the time from the emission of the laser pulses to the arrival of the received pulses, the distance from the laser scanner is determined. On the rotating cylinder 8 and the drive motor 10, an unillustrated angle decoder is mounted. From the data of this decoder results the respective direction of the laser beam 12 in an instrument-related coordinate system. Digital stationary cameras 17 and / or video cameras 18 7/30 6 can be attached to stationary instrument base 16

Pat. 0680 M ........ RIEGL Laser Measurement Systems • · · · · ········································································ • ·················. These cameras and the laser scanner are protected by an exit window 19 against environmental influences. The removal data supplied by the evaluation device are linked to the instrument-related coordinates derived from the angle decoder 5 and stored together with the data of any digital cameras 17, 18 as a respective data record. 10 15 20 25

In order to be able to transform the instrument-related data into a superordinate, for example, global coordinate system, it is necessary on the one hand to determine the orientation of the instrument 1, 2 in space and to link this with data derived from a navigation system. To determine the position of the instrument in space an inertial navigation system (IMU), 23 is used. The navigation system used for determining the position is generally based on a satellite-based system (GNNS, for example GPS). While the arrangement of this navigation system on the instrument 1, 2 is relatively uncritical, it is of crucial importance that the inertial navigation unit (IMU) 23 is completely rigid with the instrument, in this case with the laser scanner 1, 2, to a module 3 connected is. This module 3 comprises a platform 20 on which on the one hand the instrument base 16 is arranged with the rotating wedge prism 11, on the other hand carries the platform 20, the receiver optics 14 with the receiving unit 15, and four columns 21, which is welded to a plate 22. On this plate 22, the inertial navigation unit (IMU), 23 is rigidly attached.

With this frame 21, 22 and the laser source 4 is connected. The module 3 consisting of laser scanner 1, 2 and the inertial navigation unit IMU, 23 is connected to the mounting plate 31 and the plate 33 with 30 Dämpfimgselemente 24. These elements 24 serve primarily to 8/30 7

Pat. 0680 • · • • • • RIEGL Laser Measurement Systems • · ♦ »·· · · ·

Deformations of the outer structure 31-33 of the instrument, which may result, for example, by unequal heating thereof, not to be transferred to the module 3. 5 In the carrier vehicles, such as in surface aircraft and

Helicopters installed opto-electronic instruments are exposed to vibration and a wide range of vibrations and shocks, which are excited by drive motors as well as external influences. The same applies to water, land and rail vehicles. When the instruments are subjected to these forces, many of these opto-electronic instruments are relatively insensitive to dislocations in the direction of the optical axis 7 and normal to it. On the other hand, it is critical if these forces induce torsional vibrations of the instruments about axes that are normal to the optical axis. As a rule, the measuring distance is orders of magnitude larger than the instrument, so that even with small torsional vibration amplitudes considerable dislocations of the measuring points result. In the case of low-frequency oscillations, this can be compensated for by measuring the changes in the orientation of the instrument by means of the Inertial Navigation System (IMU), 23 and assigning instrument-related coordinates corresponding to the measured values. However, with higher frequency vibrations that the IMU can not follow, unacceptable measurement errors will occur. This problem not only occurs with laser scanners but also, for example, with digital still and video cameras and many other instruments with the 25 most diverse optoelectronic sensors. According to a feature of

Invention, this problem can be solved by the fact that the mounting points of the instrument are selected in the carrier vehicle so that the forces introduced into the system are directed to the instrument's center of gravity, or compensate for the center of gravity related 30 moments of these forces. 9/30 8

Pat. 0680 f (m> RIEGL Laser Measurement Systems • 4 4 4 · 4 4 · 4 4 ♦ · 4 4 4 4 44 4 ··· • 4 4 4 · 4 4 · · · · * 44 44 44 44 44 4

In the Fig.2 such an arrangement is shown. The laser scanner 1, 2 is slightly modified from that shown in FIG. 1, in particular as regards the arrangement of the damping elements 24 and their support on the outer frame and the instrument module 3.

Under the mounting plate 31 of the laser scanner 1, 2, a further plate 25 is provided, to which four so-called Drahtseilfedem 26 are attached.

The other side of these springs 26 is connected to the platform 27, which can be attached to the structure of the carrier vehicle 10 with screws, not shown. The springs are tuned with the mass of the instrument module 3 so as to form together with this a mechanical low-pass filter. The cutoff frequency is chosen so that only vibrations can reach the instrument module 3, which can still be detected by the IMU, 23 metrologically. The plate 25 is positioned on the instrument 15 so that the plane of its underside over which the

Excited forces are introduced into the system, the center of gravity 28 of the instrument including the plate 25 contains. Thus, torsional vibrations of the instrument about axes which are normal to the optical axis, suppressed as far as possible. 20

The spring assembly 25 to 27 is an integral part of the instrument, which is specially adapted to the system and is installed and removed together with this in the carrier vehicle. In the illustrated example, a two-stage mechanical decoupling 25 is realized. A first, which prevents the transfer of deformations to the module and a second, which minimizes the effects of vibrations, vibrations and forces introduced into the system by the host vehicle. 10/30 9

Pat. 0680 RIEGL Laser Measurement Systems • ········································································· •························ »«

FIG. 3 shows a further example of the assembly of an opto-electronic instrument which is intended for use in a carrier vehicle, wherein the illustration of the rigid frame structure fastened to the carrier vehicle has been dispensed with for reasons of clarity. The consisting of laser scanner 1,2 and IMU, 23 module 3 is based on the one hand with the plate 31 and three spring / damping elements 24 and with the IMU housing via single, similar spring / damping element 24 on this frame construction. Vibrations, vibrations, etc. of the carrier vehicle act on the frame structure, the three attached to the mounting plate 31 spring / damping elements 24, and attached to the IMU housing single element 24. The center of gravity 28 of the module 3 is in this example on the instrument axis in a distance a from this single element 24. The three elements 24 on the mounting plate 31 is the distance of the center of gravity 28 _b, where a is equal to 3 b. Thus, the moments of the initiated, normal to the optical axis 7 directed force components are balanced and it is the excitation of a torsional vibration of the module avoided.

Fig. 4 shows an alternative arrangement of the spring / damping elements 24. These are arranged in the corners of a virtual cube and aligned with the center of the cube. The elements 24 are based on the other side analogous to FIG. 3 on an unillustrated frame structure connected to the structure of the carrier vehicle. The center of the virtual cube substantially coincides with the center of gravity 28 of the module 3, so that no torsional vibrations of the module 3 are excited by the introduced forces. The elements 24 are tuned in their entirety with the mass of the module and constitute a spring / mass system, which acts as a mechanical low-pass filter and passes only forces in a frequency range on the module, which 11/30

Pat. 0680 RIEGL Laser Measurement Systems ··············································································································································································

Excite movements of the module 3, which are metrologically detectable by the IMU, 23.

Instead of arranging the spring / damping elements at the corner points of a virtual cube, this can also be arranged at the corner points of other regular bodies, for example at the vertices of a regular virtual tetrahedron.

In contrast to the instrument with a two-stage mechanical decoupling shown in FIG. 2, the systems shown in FIGS. 3 and 4 have a one-stage mechanical decoupling.

RIEGL

Horn, on 31.01.2013

Laser Measurement Systems GmbH ΛΛ 12/30

Claims (12)

Pat. 0680 RIEGL Laser Measurement Systems • · · · · · ··· «· • ·············································· · · RIEGL Laser Measurement Systems GmbH. HORN CLAIMS 1. A mounting system for an optoelectronic instrument in a host vehicle, the optoelectronic instrument having an inertial navigation system for detecting at least the orientation of the instrument in space, but possibly also determining its position in a coordinate system, into a rigid module and the data acquired by the optoelectronic instrument, for example from a laser descent meter or a laser scanner, is linked to the data supplied by the inertial navigation system of the orientation of the instrument to data records, wherein the module formed from the instrument and the navigation system with the structure the carrier vehicle via spring / damping elements is characterized in that the spring / damping elements are designed and arranged so that they form a mechanical low-pass filter together with the mass of the module which vibrations of Carrier vehicle, which are above a Grenzffequenz substantially absorbed low-frequency vibrations but transmits to the module, wherein the cutoff frequency is chosen so that the transmitted by the spring / damping elements, low-frequency movements of the module from the inertial navigation system can be detected by data. Pat. 0680 · ** ·· ** · • KlBGl »Lase» Measurement Systems ········ t ··· ^ 2. mounting system for an opto-electronic instrument according to claim 1, characterized in that provided on the carrier vehicle stabilized platform characterized in that at least the module formed from the instrument and the navigation system with the interposition of spring-damping elements on the stabilized platform is mounted, wherein the spring - / damping elements are designed and arranged so that they form a mechanical low-pass filter together with the mass of the module, which substantially absorbs vibrations of the stabilized platform, which is above a cutoff frequency, low-frequency oscillations but transmits to the module, the cutoff frequency chosen is that the transmitted by the spring / damping elements, low-frequency movements of the module from the inertial navigation system can be detected by data. 3. mounting system for an opto-electronic instrument in a carrier vehicle according to claim 1 or 2, characterized in that the mounting system comprises a two-stage mechanical decoupling, on the one hand, the rigid module is mechanically decoupled from the support structure to not transmit deformations of the same to the module and on the other hand, the spring / damping elements are formed so that they form a mechanical low-pass filter together with the mass of the module and its support structure, the vibrations of the host vehicle, which are above the cutoff frequency substantially absorbed, but transmits low-frequency vibrations to the module, said Limit frequency is selected so that the permitted by the spring / damping elements low-frequency movements of the module from the inertial navigation system can be detected in terms of data. (FIG 2) 14/30 2 Pat. 0680 RIEGL Laser Measurement Systems • ···························································· ·· ·· ·· »· · · · 4. mounting system for an opto-electronic instrument according to one of the claims 1 to 3, characterized in that the cutoff frequency is set at about 25 Hz. 5. mounting system for an opto-electronic instrument according to one of the claims 1 to 4, characterized in that the module is movably suspended or braced in all three coordinate directions. 6. mounting system for an opto-electronic instrument according to one of the claims 1 to 5, characterized in that the spring and damping elements are designed at the individual points of attack on the module, taking into account their position with respect to the center of gravity of the module so that both longitudinal - As torsional vibrations or deformations are largely damped. (FIG.4) 7. mounting system for an opto-electronic instrument according to claim 6, characterized in that the spring / Dämpfimgselemente are formed and positioned on the module that based on the center of gravity of the module, the sum of the moments of those forces that are transferable to the module , is essentially zero. (FIG.4) 8. mounting system for an opto-electronic instrument according to one of the claims 1 to 5, characterized in that 15/30 3 Pat. 0680 RIEGL Laser Measurement Systems I ·· ·· ·· · ♦ ···· ····· ♦ ···· ..... the spring and damping elements are designed at the individual points of attack on the module, taking into account their position relative to the center of gravity of the module so that torsional vibrations are largely damped. (FIG. 3) 5 9. assembly system for an opto-electronic instrument according to claim 8, characterized in that the spring / damping elements are designed and positioned on the module 10, that based on the center of gravity of the module, the sum of the moments of those force components that on the Modulus are transferable and are normal to the optical axis of the opto-electronic instrument, is substantially zero. (FIG.3) 10. mounting system for an opto-electronic instrument according to one of the preceding claims, characterized in that provided on the module connecting pieces for the rigid attachment of video and / or photo cameras and or or of navigation systems or their sensors 20 and optionally of Kompensationsmassen are. 11. Opto-electronic instrument with a mounting system according to one of the preceding claims, characterized in that the instrument 25 comprises a platform or the like., Which is rigidly connected to the structure of the carrier vehicle and that the spring / damping elements between the instrument module and the Platform are provided. (FIG.2) 12. Opto-electronic instrument according to claim 11, characterized in that 16/30 4 Pat. 0680 RIEGL Laser Measurement Systems the housing of the instrument module has a flange od. Like. And between the flange and the platform, the spring / damping elements are arranged and the center of gravity of the instrument module is located substantially in the flange plane. (FIG 2) RIEGL Horn, on 31.01. 2013 Laser Measurement Systems GmbH 17/30 5