CA2104179A1 - Isolation of environmental accelerations and tilts on moving platform - Google Patents
Isolation of environmental accelerations and tilts on moving platformInfo
- Publication number
- CA2104179A1 CA2104179A1 CA 2104179 CA2104179A CA2104179A1 CA 2104179 A1 CA2104179 A1 CA 2104179A1 CA 2104179 CA2104179 CA 2104179 CA 2104179 A CA2104179 A CA 2104179A CA 2104179 A1 CA2104179 A1 CA 2104179A1
- Authority
- CA
- Canada
- Prior art keywords
- sensor
- platform
- tilting device
- tilt
- tilting
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Abandoned
Links
Classifications
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01C—MEASURING DISTANCES, LEVELS OR BEARINGS; SURVEYING; NAVIGATION; GYROSCOPIC INSTRUMENTS; PHOTOGRAMMETRY OR VIDEOGRAMMETRY
- G01C9/00—Measuring inclination, e.g. by clinometers, by levels
- G01C9/02—Details
- G01C9/08—Means for compensating acceleration forces due to movement of instrument
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
- F16F—SPRINGS; SHOCK-ABSORBERS; MEANS FOR DAMPING VIBRATION
- F16F15/00—Suppression of vibrations in systems; Means or arrangements for avoiding or reducing out-of-balance forces, e.g. due to motion
- F16F15/02—Suppression of vibrations of non-rotating, e.g. reciprocating systems; Suppression of vibrations of rotating systems by use of members not moving with the rotating systems
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01C—MEASURING DISTANCES, LEVELS OR BEARINGS; SURVEYING; NAVIGATION; GYROSCOPIC INSTRUMENTS; PHOTOGRAMMETRY OR VIDEOGRAMMETRY
- G01C21/00—Navigation; Navigational instruments not provided for in groups G01C1/00 - G01C19/00
- G01C21/10—Navigation; Navigational instruments not provided for in groups G01C1/00 - G01C19/00 by using measurements of speed or acceleration
- G01C21/12—Navigation; Navigational instruments not provided for in groups G01C1/00 - G01C19/00 by using measurements of speed or acceleration executed aboard the object being navigated; Dead reckoning
- G01C21/16—Navigation; Navigational instruments not provided for in groups G01C1/00 - G01C19/00 by using measurements of speed or acceleration executed aboard the object being navigated; Dead reckoning by integrating acceleration or speed, i.e. inertial navigation
- G01C21/18—Stabilised platforms, e.g. by gyroscope
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01V—GEOPHYSICS; GRAVITATIONAL MEASUREMENTS; DETECTING MASSES OR OBJECTS; TAGS
- G01V7/00—Measuring gravitational fields or waves; Gravimetric prospecting or detecting
- G01V7/16—Measuring gravitational fields or waves; Gravimetric prospecting or detecting specially adapted for use on moving platforms, e.g. ship, aircraft
Landscapes
- Engineering & Computer Science (AREA)
- Physics & Mathematics (AREA)
- Radar, Positioning & Navigation (AREA)
- Remote Sensing (AREA)
- General Physics & Mathematics (AREA)
- Aviation & Aerospace Engineering (AREA)
- General Engineering & Computer Science (AREA)
- General Life Sciences & Earth Sciences (AREA)
- Life Sciences & Earth Sciences (AREA)
- Geophysics (AREA)
- Acoustics & Sound (AREA)
- Ocean & Marine Engineering (AREA)
- Mechanical Engineering (AREA)
- Automation & Control Theory (AREA)
- Vibration Prevention Devices (AREA)
- Platform Screen Doors And Railroad Systems (AREA)
- Warehouses Or Storage Devices (AREA)
Abstract
Abstract of the Disclosure:
A system for compensating for horizontal common-mode acceleration and tilt on a moving platform including a laboratory motion isolation table or borehole logging probe, by transforming horizontal accelerations of the platform into vertical accelerations, comprises a tilt table mounted on the platform, a sensor mounted on the tilt table or on the platform for sensing linear accelerations and tilts to which the platform is subjected, and a tilting device mounted on the platform and responsive to the sensor for tilting the tilt table to compensate for horizontal accelerations and tilts to which the platform is subjected.
A system for compensating for horizontal common-mode acceleration and tilt on a moving platform including a laboratory motion isolation table or borehole logging probe, by transforming horizontal accelerations of the platform into vertical accelerations, comprises a tilt table mounted on the platform, a sensor mounted on the tilt table or on the platform for sensing linear accelerations and tilts to which the platform is subjected, and a tilting device mounted on the platform and responsive to the sensor for tilting the tilt table to compensate for horizontal accelerations and tilts to which the platform is subjected.
Description
, :~ ISOL~ATION OF I~NVIRONDlEMTAI~
ACC13L~3RATIONS AND TII~TS ON MOVING PI.ATFORM
! This invention relates to a system for compensating for the effects of horizontal accelerations and tilts, on a moving platform, such as an air-, land-, water-, or space-borne vehicle or in a borehole-logging probe, or on a laboratory motion isolation (seismic) table.
~ac~ground of the Invention When carrying out high resolution measurements involving free or partially free masses on a moving platform, it is often desirable to compensate for the effect of horizontal accelerations as well as tilts.
For example, let us consider an air-borne gravity gradiometer based either on pendulous or other accelerometer pairs. One way to reduce the effect of horizontal common-mode acceleration on the above sensors is to match the accelerometers over a very broad dynamic range and to closely maintain their alignment. Neither may be attainable to a sufficient degree with present technology.
Tilts can, with expensive gimballed platforms, be , ~ maintained to within a few micro-radians. Compensation for horizontal accelerations (which are typically .01 -.02 G during survey regime) has not been accomplished to date.
Statement of Invention `~ The present invention is based on the principle of 3 equivalence between tilt ~ (x,) and ~ (y) and horizontal accelerations (x) or (y), which states that an accelerometer cannot distinguish between horizontal acceleration and tilt. Consequently, the effect of x and y on a moving platform can be compensated for by tilting the platform by an angle ~ (x,y), where tan ~ (x) = x tan ~ (y) = y with x and y expressed in G's This operation transforms (in platform body co-ordinates), horizontal accelerations x, y into a vertical acceleration z, to which a pendulous hori~ontal accelerometer is relatively insensitive. Tilting is the most effective way to compensate for large-amplitude, low-frequency (below 1 Hz) horizontal accelerations.
High-frequency, low amplitude motions (vibrations) can be attenuated, for example with a piezo-electric (PZT) driven translational x, y, z stage.
.
The system in accordance with the present invention comprises a tilt table mounted on a moving platform including a laboratory motion isolation table or a borehole logging probe, a sensor mounted on the tilt 3 5 table or on the platform for sensing linear accelerations and tilts to which the platform is subjected, and a tilting device mounted on the platform ~; and responsive to the sensor for tilting the tilt tableto compensate for horizontal accelerations and tilts to which the platform is subjected.
The sensor may be, for example, a horizontal I accelerometer such as the QA 3000 manufactured by Sundstrand Data Control Inc., Redmond, Wash., or an electronic bubble level in closed feedback loop with the tilting device.
The sensor may also be an Inertial Measurement Unit (IMU) like H423 manufactured by Honeywell Inc. of Clearwater, Florida. If an IMU is used as a gravity sensor, it can be, for lower noise, installed on a tilt table in a Shuler-tuned closed loop configuration with the tilting device. Alternatively, the IMU may be a part of an autopilot, motion compensation or other device, working in open-loop configuration with the tilting device.
In the case of accelerometer-based gravity gradiometry, the sensor output may be provided by ;., ,, , : , , : , .. . . . -accelerometers of the gradiometer pairs. In this application, the sensor may be a part of the feedback loop with the tilting device thus substantially eliminating the horizontal cornmon-mode component of the gravity gradient signal.
The sensor output signal is preferably processed through a feedback controller for applying a regulated feedback control to the tilting device to cause the sensor base to tilt by an angle that will compensate for horizontal accelerations and tilts. The feedback controller is preferably a proportional-integral-derivative feedback controller.
The tilt table may be a two stage table comprising a first coarsely controlled stage using a servo-motor as lS a tilting device, and a second finely controlled stage using a transducer as a tilting device.
The sensor and tilting device may be combined in a single sensor/tilting unit. The sensor/tilting unit may be a critically-damped pendulum or a "dish" filled with liquid, on which the tilt table floats. In either cases a feedback controller will not be required for the first coarse stage.
Short Descri~tion of ths Drawing The invention will now be disclosed, by way of example, with reference to preferred embodiments illustrated in the accompanying drawings in which:
.: :, : : : . . .
~1UL1j ~ 9 ~:l 5 :~ Figure 1 shows a two-stage, two degrees of freedom (DOF), pitch and roll, active motion isolation table configuration which will attenuate residual horizontal . accelerations and tilts;
~3 5 Figure 2 shows a single-stage, DOF (pitch and ; roll), active motion isolation table configurationi and ; Figure 3 shows a two-stage, active motion isolation table configuration similar to Figure 1 which will additionally attenuate vibrations along x, y and z axes (five or six DOF).
~etailed Descri~tion of a Preferred ~mbodiment Referring to Figure 1, there is shown a two-stage tilt table in the form of a coarsely-controlled table and a finely-controlled table 2, which are affected by i 15 linear acceleration disturbance (t) and angular tilt disturbance (t). In accordance with the present invention, both of these disturbances are compensated for by tilting the sensor base by angle O (table 2), using a servo-motor 3 operating a precision lead screw (not shown) to provide a linear displacement to a ~.
resolution of about 5 - 10 micro-radians. For greater resolution than can be achieved with a mechanical , device, a pie~oelectric device (PZT) device, or electro - - -.
strictive or magneto-strictive (EST or MST
respectively), or any other suitable transducer 4 is mounted on table 1 to provide a resolution of the order ,: , . :
i':.; :' : , , , of 10 nano-radians or better.
or the purpose of the description, it is assumed that the disturbances to be compensated for are in the (x, z) vertical plane of motion. The tilt tables may however be modified to accommodate motions in all six degrees of freedom.
In the present embodiment, the sensors are pendulous acceleration sensors 5 and 6, which are mounted on tables 1 and 2 respectively to sense horizontal accelerations (and tilts). The output voltage V(t) of each accelerometer is sensed by à
detector 7 and fed to a feedback controller 8 which applies a feedback voltage to the servo-motor or the PZT
through a suitable driver 9 if required to thereby null the output voltages V(t) of the pendulous accelerometers.
For less demanding applications, a single-stage, two-DOF tilt table, as illustrated in Figure 2, may provide a simpler, less expensive alternative. The ~ -disturbances sensed by sensor 10 mounted on table 11 are ~ ~-applied to a feedback controller 12 or 13 or both.
Coarse deviations may be compensated by a servo-motor 14 through a suitable driver 15 while fine deviations of ~-~
the order of 10 nano-radians may be compensated by a PZT
16.
,~ l U ~~L l 7 9 .
'! 7 i On a seismic isolation table, where compensating tilts may be limited to several micro-radians, a PZT (or EST or MST) stage only can be used.
Figure 3 is a two-stage stabilized platform ~ 5 configuration such as shown in Figure 1 wherein stage 2 ¦ additionally includes a x,y,z vibration isolation stage ' which is part of the tilt table. In this embodiment high fre~uency low-amplitude vibrations can be attenuated with x,y,z translation devices such as piezo- - -electric (PZT) devices 4, 16, 17 working in closed loop with a suitable triaxial vibration sensor 18.
The configuration shown in Figure 3 can accommodate five degrees of freedom. The sixth degree (yaw compensation) is not shown but can be added using the same technique.
A Proportional-Integral-Derivative (PID) feedback control is preferably used to stabilize the table as a function of the pendulum output where:
e = KpV + Kd V + Ki ¦ Vdt +Vn where e = voltage applied to the PZT
Kp = proportional control gain Ki = integral control gain Kd = derivative control gain Vn = electronic noise If the tilt assembly is critically damped (i.e. no control induced oscillations) then the gains of each r~ 9 :. 8 : control component are related such that:
~:, K2p - 4 KdKi > 0 and ~c = Ki/Kp < 0.1 Hz such that integral control is used effectively where it is needed most (in this case for frequencies ~c less than 0.1 Hz).
, All modes of PID control are needed because:
`. 1) Proportional: is usually needed with integral and derivative control.
~, 10 2) Integral: is required for reducing the steady state tilt angle in the feedback ~, loop because tilt frecluencies close `~ to DC require a high gain.
3) Derivative: for decreasing the feedback response j 15 time at high frequencies as well as applying a phase-lead control.
Although the invention has been disclosed, by way of example, with reference to preferred embodiments, it :~
is to be understood that it is not limited to such embodiments and that other alternatives are also envisaged within the scope of the following claims: ~-~
ACC13L~3RATIONS AND TII~TS ON MOVING PI.ATFORM
! This invention relates to a system for compensating for the effects of horizontal accelerations and tilts, on a moving platform, such as an air-, land-, water-, or space-borne vehicle or in a borehole-logging probe, or on a laboratory motion isolation (seismic) table.
~ac~ground of the Invention When carrying out high resolution measurements involving free or partially free masses on a moving platform, it is often desirable to compensate for the effect of horizontal accelerations as well as tilts.
For example, let us consider an air-borne gravity gradiometer based either on pendulous or other accelerometer pairs. One way to reduce the effect of horizontal common-mode acceleration on the above sensors is to match the accelerometers over a very broad dynamic range and to closely maintain their alignment. Neither may be attainable to a sufficient degree with present technology.
Tilts can, with expensive gimballed platforms, be , ~ maintained to within a few micro-radians. Compensation for horizontal accelerations (which are typically .01 -.02 G during survey regime) has not been accomplished to date.
Statement of Invention `~ The present invention is based on the principle of 3 equivalence between tilt ~ (x,) and ~ (y) and horizontal accelerations (x) or (y), which states that an accelerometer cannot distinguish between horizontal acceleration and tilt. Consequently, the effect of x and y on a moving platform can be compensated for by tilting the platform by an angle ~ (x,y), where tan ~ (x) = x tan ~ (y) = y with x and y expressed in G's This operation transforms (in platform body co-ordinates), horizontal accelerations x, y into a vertical acceleration z, to which a pendulous hori~ontal accelerometer is relatively insensitive. Tilting is the most effective way to compensate for large-amplitude, low-frequency (below 1 Hz) horizontal accelerations.
High-frequency, low amplitude motions (vibrations) can be attenuated, for example with a piezo-electric (PZT) driven translational x, y, z stage.
.
The system in accordance with the present invention comprises a tilt table mounted on a moving platform including a laboratory motion isolation table or a borehole logging probe, a sensor mounted on the tilt 3 5 table or on the platform for sensing linear accelerations and tilts to which the platform is subjected, and a tilting device mounted on the platform ~; and responsive to the sensor for tilting the tilt tableto compensate for horizontal accelerations and tilts to which the platform is subjected.
The sensor may be, for example, a horizontal I accelerometer such as the QA 3000 manufactured by Sundstrand Data Control Inc., Redmond, Wash., or an electronic bubble level in closed feedback loop with the tilting device.
The sensor may also be an Inertial Measurement Unit (IMU) like H423 manufactured by Honeywell Inc. of Clearwater, Florida. If an IMU is used as a gravity sensor, it can be, for lower noise, installed on a tilt table in a Shuler-tuned closed loop configuration with the tilting device. Alternatively, the IMU may be a part of an autopilot, motion compensation or other device, working in open-loop configuration with the tilting device.
In the case of accelerometer-based gravity gradiometry, the sensor output may be provided by ;., ,, , : , , : , .. . . . -accelerometers of the gradiometer pairs. In this application, the sensor may be a part of the feedback loop with the tilting device thus substantially eliminating the horizontal cornmon-mode component of the gravity gradient signal.
The sensor output signal is preferably processed through a feedback controller for applying a regulated feedback control to the tilting device to cause the sensor base to tilt by an angle that will compensate for horizontal accelerations and tilts. The feedback controller is preferably a proportional-integral-derivative feedback controller.
The tilt table may be a two stage table comprising a first coarsely controlled stage using a servo-motor as lS a tilting device, and a second finely controlled stage using a transducer as a tilting device.
The sensor and tilting device may be combined in a single sensor/tilting unit. The sensor/tilting unit may be a critically-damped pendulum or a "dish" filled with liquid, on which the tilt table floats. In either cases a feedback controller will not be required for the first coarse stage.
Short Descri~tion of ths Drawing The invention will now be disclosed, by way of example, with reference to preferred embodiments illustrated in the accompanying drawings in which:
.: :, : : : . . .
~1UL1j ~ 9 ~:l 5 :~ Figure 1 shows a two-stage, two degrees of freedom (DOF), pitch and roll, active motion isolation table configuration which will attenuate residual horizontal . accelerations and tilts;
~3 5 Figure 2 shows a single-stage, DOF (pitch and ; roll), active motion isolation table configurationi and ; Figure 3 shows a two-stage, active motion isolation table configuration similar to Figure 1 which will additionally attenuate vibrations along x, y and z axes (five or six DOF).
~etailed Descri~tion of a Preferred ~mbodiment Referring to Figure 1, there is shown a two-stage tilt table in the form of a coarsely-controlled table and a finely-controlled table 2, which are affected by i 15 linear acceleration disturbance (t) and angular tilt disturbance (t). In accordance with the present invention, both of these disturbances are compensated for by tilting the sensor base by angle O (table 2), using a servo-motor 3 operating a precision lead screw (not shown) to provide a linear displacement to a ~.
resolution of about 5 - 10 micro-radians. For greater resolution than can be achieved with a mechanical , device, a pie~oelectric device (PZT) device, or electro - - -.
strictive or magneto-strictive (EST or MST
respectively), or any other suitable transducer 4 is mounted on table 1 to provide a resolution of the order ,: , . :
i':.; :' : , , , of 10 nano-radians or better.
or the purpose of the description, it is assumed that the disturbances to be compensated for are in the (x, z) vertical plane of motion. The tilt tables may however be modified to accommodate motions in all six degrees of freedom.
In the present embodiment, the sensors are pendulous acceleration sensors 5 and 6, which are mounted on tables 1 and 2 respectively to sense horizontal accelerations (and tilts). The output voltage V(t) of each accelerometer is sensed by à
detector 7 and fed to a feedback controller 8 which applies a feedback voltage to the servo-motor or the PZT
through a suitable driver 9 if required to thereby null the output voltages V(t) of the pendulous accelerometers.
For less demanding applications, a single-stage, two-DOF tilt table, as illustrated in Figure 2, may provide a simpler, less expensive alternative. The ~ -disturbances sensed by sensor 10 mounted on table 11 are ~ ~-applied to a feedback controller 12 or 13 or both.
Coarse deviations may be compensated by a servo-motor 14 through a suitable driver 15 while fine deviations of ~-~
the order of 10 nano-radians may be compensated by a PZT
16.
,~ l U ~~L l 7 9 .
'! 7 i On a seismic isolation table, where compensating tilts may be limited to several micro-radians, a PZT (or EST or MST) stage only can be used.
Figure 3 is a two-stage stabilized platform ~ 5 configuration such as shown in Figure 1 wherein stage 2 ¦ additionally includes a x,y,z vibration isolation stage ' which is part of the tilt table. In this embodiment high fre~uency low-amplitude vibrations can be attenuated with x,y,z translation devices such as piezo- - -electric (PZT) devices 4, 16, 17 working in closed loop with a suitable triaxial vibration sensor 18.
The configuration shown in Figure 3 can accommodate five degrees of freedom. The sixth degree (yaw compensation) is not shown but can be added using the same technique.
A Proportional-Integral-Derivative (PID) feedback control is preferably used to stabilize the table as a function of the pendulum output where:
e = KpV + Kd V + Ki ¦ Vdt +Vn where e = voltage applied to the PZT
Kp = proportional control gain Ki = integral control gain Kd = derivative control gain Vn = electronic noise If the tilt assembly is critically damped (i.e. no control induced oscillations) then the gains of each r~ 9 :. 8 : control component are related such that:
~:, K2p - 4 KdKi > 0 and ~c = Ki/Kp < 0.1 Hz such that integral control is used effectively where it is needed most (in this case for frequencies ~c less than 0.1 Hz).
, All modes of PID control are needed because:
`. 1) Proportional: is usually needed with integral and derivative control.
~, 10 2) Integral: is required for reducing the steady state tilt angle in the feedback ~, loop because tilt frecluencies close `~ to DC require a high gain.
3) Derivative: for decreasing the feedback response j 15 time at high frequencies as well as applying a phase-lead control.
Although the invention has been disclosed, by way of example, with reference to preferred embodiments, it :~
is to be understood that it is not limited to such embodiments and that other alternatives are also envisaged within the scope of the following claims: ~-~
Claims (11)
1. A system for compensating for horizontal common-mode acceleration and tilt on a moving platform including a laboratory motion isolation table or borehole logging probe, by transforming horizontal accelerations of the platform into vertical accelerations, comprising:
a) a tilt table mounted on the platform;
b) a sensor mounted on the tilt table or on the platform for sensing linear accelerations and tilts to which the platform is subjected; and c) a tilting device mounted on the platform and responsive to the said sensor for tilting the tilt table to compensate for horizontal accelerations and tilts to which the platform is subjected.
a) a tilt table mounted on the platform;
b) a sensor mounted on the tilt table or on the platform for sensing linear accelerations and tilts to which the platform is subjected; and c) a tilting device mounted on the platform and responsive to the said sensor for tilting the tilt table to compensate for horizontal accelerations and tilts to which the platform is subjected.
2. A system as defined in claim 1, wherein the sensor is a horizontal accelerometer or an electronic bubble level, in closed feedback loop with the said tilting device.
3. A system as defined in claim 1, wherein in case of accelerometer-based gravity gradiometry using accelerometer pairs, the sensor output is provided by at least one accelerometer of the gradiometer pairs, in closed feedback loop with the said tilting device.
4. A system as defined in claim 1, wherein the sensor is an Inertial Measurement Unit (IMU), which may be installed either on a tilt table capable of working in a Shuler-tuned closed loop configuration with the tilting device, or separately in open loop configuration with the tilting device, as a part of an autopilot, motion compensation or other device.
5. A system as defined in claim 1, further comprising a feedback controller responsive to the output of the sensor for applying a regulated feedback control to the tilting device to cause the table to tilt by an angle that will compensate for horizontal accelerations and tilts.
6. A system as defined in claim 5, wherein the feedback controller is a proportional-integral-derivative feedback controller.
7. A system as defined in claim 1 wherein said tilt table is a two-stage table comprising a first coarsely controlled stage using a servo-motor as a tilting device, and a second finely-controlled stage using a transducer as a tilting device.
8. A system as defined in claim 7, wherein the second stage includes a high frequency vibration insolation stage comprising x, y,z translation devices responsive to vibration sensors.
9. A system as defined in claim 7, wherein the sensor and tilting device are combined in a single sensor/tilting unit.
10. A system as defined in claim 9, wherein the sensor/tilting unit is a critically-damped pendulum.
11. A system as defined in claim 9, wherein the sensor/tilting unit is a dish filled with liquid, on which the tilt table floats.
Priority Applications (3)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA 2104179 CA2104179A1 (en) | 1993-08-16 | 1993-08-16 | Isolation of environmental accelerations and tilts on moving platform |
| PCT/CA1994/000441 WO1995005576A1 (en) | 1993-08-16 | 1994-08-16 | Isolation of environmental accelerations and tilts on moving platform |
| AU74551/94A AU7455194A (en) | 1993-08-16 | 1994-08-16 | Isolation of environmental accelerations and tilts on moving platform |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA 2104179 CA2104179A1 (en) | 1993-08-16 | 1993-08-16 | Isolation of environmental accelerations and tilts on moving platform |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA2104179A1 true CA2104179A1 (en) | 1995-02-17 |
Family
ID=4152153
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA 2104179 Abandoned CA2104179A1 (en) | 1993-08-16 | 1993-08-16 | Isolation of environmental accelerations and tilts on moving platform |
Country Status (3)
| Country | Link |
|---|---|
| AU (1) | AU7455194A (en) |
| CA (1) | CA2104179A1 (en) |
| WO (1) | WO1995005576A1 (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US6213442B1 (en) | 1998-10-08 | 2001-04-10 | Lord Corporation | Isolation system for isolation tables and the like |
| CN115218860A (en) * | 2022-09-20 | 2022-10-21 | 四川高速公路建设开发集团有限公司 | Road deformation prediction method based on Mems acceleration sensor |
Families Citing this family (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP3114571B2 (en) * | 1995-05-26 | 2000-12-04 | 株式会社村田製作所 | Acceleration sensor |
| MXPA00011040A (en) * | 1998-05-12 | 2003-08-01 | Lockheed Corp | System and process for secondary hydrocarbon recovery. |
| JP2002031187A (en) * | 2000-07-13 | 2002-01-31 | Ebara Corp | Vibration resistant device using magnetic levitation device |
| RU2298211C2 (en) * | 2000-11-28 | 2007-04-27 | Бизнес Артс Инк. | Mode of gravitational gradiometry and arrangements for its realization |
| RU2522116C1 (en) * | 2013-04-05 | 2014-07-10 | Анатолий Борисович Попов | Method of inserting laser beam vertical line of ballistic gravimeter and gravimeter for realising said method |
Family Cites Families (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US3015962A (en) * | 1955-11-30 | 1962-01-09 | Research Corp | Method and apparatus for indicating the vertical |
| FR1525230A (en) * | 1967-04-03 | 1968-05-17 | Sagem | Improvements made to installations with apparatus sensitive to apparent vertical |
| US3668932A (en) * | 1970-12-04 | 1972-06-13 | Hughes Aircraft Co | Gravity gradient meter |
-
1993
- 1993-08-16 CA CA 2104179 patent/CA2104179A1/en not_active Abandoned
-
1994
- 1994-08-16 AU AU74551/94A patent/AU7455194A/en not_active Abandoned
- 1994-08-16 WO PCT/CA1994/000441 patent/WO1995005576A1/en active Application Filing
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US6213442B1 (en) | 1998-10-08 | 2001-04-10 | Lord Corporation | Isolation system for isolation tables and the like |
| CN115218860A (en) * | 2022-09-20 | 2022-10-21 | 四川高速公路建设开发集团有限公司 | Road deformation prediction method based on Mems acceleration sensor |
| CN115218860B (en) * | 2022-09-20 | 2022-12-09 | 四川高速公路建设开发集团有限公司 | Road deformation prediction method based on Mems acceleration sensor |
Also Published As
| Publication number | Publication date |
|---|---|
| WO1995005576A1 (en) | 1995-02-23 |
| AU7455194A (en) | 1995-03-14 |
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