KR0164659B1 - Method and apparatus for 6 freedom degree motion measuring and location tracking of moving ship using servo acceleration meter and angle meter - Google Patents

Abstract

The present invention measures the six degrees of freedom motion of the hull operating at sea and sea using servo acceleration sensor, tilt sensor, geomagnetic sensor, pressure sensor and ultrasonic sensor, and performs filtering and signal processing for actual motion estimation. As a hull motion measuring device, it corrects measurement errors according to temperature changes, measures the working depth and working altitude, corrects the motion components, and uses the low-level position data given by general-purpose position tracking devices to measure the movement data at regular intervals. It is characterized in that the function of obtaining a highly accurate measurement result with a low cost measurement system is implemented by a signal processing processor.

Description

Motion Measurement and Position Tracking Method of Six Degrees of Freedom Motion of a Moving Hull Using Servo Accelerometer and Inclinometer

1 is a conceptual diagram of the operation of ships and marine equipment operating in the ocean.

2 is a conceptual diagram of position error reduction of a combined motion measurement system.

3 is a schematic diagram of a motion measurement and position tracking system of a moving hull using a servo accelerometer and an inclinometer.

* Explanation of symbols for main parts of the drawings

1: 32-bit digital signal processing processor (DSP: TMS320C31)

2: Software built-in program memory (EPROM)

3: Data storage memory (SRAM)

4: Programmable Logic Device (EPLD)

5: LCD monitor 6: RS232C asynchronous communication port

7: AD converter 8: DA converter

9: digital signal input port 10: X-direction servo accelerometer

11: Y-direction servo accelerometer 12: Z-direction servo accelerometer

13: Pitch-direction inclinometer 14: Roll-direction inclinometer

15: Magnetic Compass 16: Thermometer

The present invention relates to a method and apparatus for measuring and positioning a six degree of freedom motion of a moving hull using a servo accelerometer and an inclinometer. The present invention relates to acceleration, inclination angle, azimuth, hydraulic pressure, Changes in altitude (wave height in the case of a waterline) are measured using servo acceleration sensors, tilt sensors, geomagnetic sensors, pressure sensors, and ultrasonic sensors, and these signals are computed quickly using a signal processor. It relates to a measurement system for estimating the six degrees of freedom motion component of the hull in real time. In addition, low-cost and high-precision positioning methods and devices are implemented by using low-level data obtained from general-purpose positioning systems for signal correction of measurement systems.

General vessels operating at sea, offshore structures suspended in fixed positions, towed ships towed by ships, remotely operated vehicles (ROVs) operating in the sea, autonomous unmanned submersibles that are not connected to cables Autonomous Underwater Vehicles (AUV) are the basic data for auditing the stability of ships, ensuring the correctness of work and controlling the system, and require the motion components of the hull and their position in absolute coordinates.

The GPS method using satellites is most widely used to measure the position of the watercraft, and the sonar position tracking device (SBL, LBL, SSBL system) using sonar is used for the underwater measurement. The gyro, acceleration sensor, inclination sensor, etc. are used for the motion measurement of the watercraft, and the high-precision expensive inertial navigation system (INS) is used for the motion measurement and position measurement of underwater ships such as submarines or manned submersibles.

However, the use of GPS is limited to the horizontal position estimation. Among the underwater acoustic positioning devices, SBL and LBL methods require a separate supporting ship and are difficult to operate. SSBL is sensitive to noise and requires separate signal processing. . In addition, the gyro system and inertial navigation system for the measurement of motion is too expensive, and low frequency drift is large for the underwater system that operates at low speed, such as an unmanned submersible, and has a disadvantage that it cannot be used for a long time. Among these existing measurement systems, precision grades are more expensive and difficult to use than unmanned submersibles for exploration or light work, and intermediate measurement systems are not enough to be used for automatic navigation of underwater hulls.

The present invention compensates for the disadvantages of the conventional measuring devices, and measures the movement of the ship moving at sea and in the sea, and combines the movement measurement data with the positioning data obtained by using a cheap general-purpose position measuring device to position the precision class. The object is to provide a measurement system capable of measuring.

In order to achieve the above object, the present invention directly calculates the position and posture of the hull from the position change amount obtained by the motion measurement in the short time range, and the data obtained from the general position measuring device (SSBL or GPS) in the long time range. It has a function to correct the error term by the motion measurement by filtering and the variable estimation, it is characterized in that it is implemented by a high-speed signal processing dedicated processor (DSP) so that this function is made in real time.

The present invention is a method and apparatus for performing precision position estimation using a measurement system composed of general-purpose sensors in performing position measurement of a moving ship in the sea and sea.

Hereinafter, the present invention will be described in detail with reference to the accompanying drawings.

1 is a conceptual view of the operation of the hull in the sea.

In the present invention, the measurement system and the processor are stored in a small main body and can be mounted in a small underwater equipment such as an unmanned submersible. The sonar sensor for the dynamic measurement is constructed as a separate container and is configured to be attached to the outside of the hull for easy measurement.

2 shows the principle of the present invention, the position measured by the underwater acoustic method has an error component that changes instantaneously, and the position signal by the acceleration sensor is not good for a long time. It is a conceptual diagram of correcting the motion measurement value obtained by the acceleration sensor at a predetermined time interval using the position measurement value estimated for a long time. By combining the advantages of these two systems, you can create a low-cost measurement system with the desired precision.

3 is a schematic diagram of a motion measurement and position tracking system. The system is composed of a sensor unit for measurement and a processor unit for signal processing.

The function of each part of the measurement system is as follows.

The sensor unit measures movement acceleration in x, y, and z directions using three servo acceleration sensors, measures longitudinal and roll movements using two inclination centers, and measures one geomagnetic sensor. It consists of six degrees of freedom sensors that measure the bow yaw of the hull, which is used for altitude measurement, a pressure sensor that measures the pressure in the water, and a temperature to compensate for signal changes due to temperature changes. Sensors are used for signal correction. If the system is mounted on board a ship, an altitude sonar can be installed at the bow of the ship to measure crest height.

The processor unit uses a digital signal processing processor (DSP) to construct a system capable of processing measurement signals in real time. This processor is connected to a memory that stores calculation data for filtering the acquisition signal, compensating the signal and estimating the actual variable. Some H / Ws are simplified using programmable logic devices (EPLDs).

In the sensor unit, an AD (Analog / Digital) converter is installed to acquire an input analog signal, and a DA (Digital / Analog) converter is installed so that the calculated position signal can be used externally. Among the input signals, the inclinometer signal is also used as an output signal. The distance result obtained by the altitude sonar is connected to the processor for reading by digital input.

Since the position signals obtained from general-purpose position measuring devices such as SSBL and GPS are generally given by RS232C method, RS232C serial port is installed according to them, and if there is no external position tracking device, the position data of relative coordinate system is calculated. By installing a second RS232C serial photo, the position estimation signal calculated by the motion measurement and position tracking system can be communicated with a general personal computer.

In addition, by using the LCD, a display function for the current six degrees of freedom motion signal and the calculated estimated position signal is implemented, and not only the motion signal but also the pressure, temperature, and altitude (wave height in the case of water line) are displayed. can do.

According to the hardware configuration of the present invention, as shown in FIG. 3, the personal computer 20 and the hydroacoustic position tracking system 30 or the satellite position information system 40 are selected by the conversion switch SW so that asynchronous communication of the signal processing unit is possible. It is installed to be input to the port (6) and the signal processing unit communicates with the asynchronous communication port (6) 32-bit digital signal processing processor (1), data memory (3), programmable logic device (4), liquid crystal monitor (5) ), AD converter (7), DA converter (8), and digital signal input (9), which are connected to the sensor, among which AD converter (7) is the X-direction servo accelerometer (10), Y -Directional Servo Accelerometer 11, Z-direction Servo Accelerometer 12, Pitch Directional Inclinometer 13 Lateral Inclinometer 14 Yaw, Orientation 15, Thermometer 16 Is connected to the pressure gauge 17 and the DA converter 8 is the six degrees of freedom motion signal (X, Y, Z, longitudinal inclination, transverse direction). Connected to four, each player slope) and (digital signal input 9) is connected to the digital input port 19 via a high hydrogen or (18).

As such, the present invention constitutes a low-cost measurement system for performing six-degree-of-freedom motion measurement and position tracking of mobile ships operating at sea, and is mounted on equipment used for offshore development to ensure more accurate working positions and ensure high reliability. It can be used for underwater work, and can accurately estimate the movement trajectory of marine equipment, thereby contributing to the automation of marine work.

Claims (2)

The six degrees of freedom movement of the hull operating at sea is measured using servo acceleration sensor, inclination sensor, geomagnetic sensor, pressure sensor and ultrasonic sensor. It corrects errors, uses motion depth and working altitude to correct motion components, and corrects hull motion data estimated at constant time intervals using low-level position data obtained from general-purpose position tracking devices. If there is no external position tracking device, it can output the position data for the relative coordinate system and implement analog output, LCD screen display, serial communication, etc. for hull motion measurement and position tracking results. 6-DOF Freedom Motion Measurement and Position Tracking Method The personal computer 20 and the hydroacoustic position tracking system 30 or the satellite position information system 40 are selected by the conversion switch SW ₁ and installed to be input to the asynchronous communication port 6 of the signal processing section. 32-bit digital signal processing processor (1) and data memory (3), programmable logic device (4), liquid crystal monitor (5), AD converter (7), DA converter (8) in communication with the asynchronous communication port (6). ), Which is connected to the digital signal input 9 and is connected to the sensor unit, and is connected to the AD converter 7, the DA converter 8, and the digital signal input 9. The DA converter 7 is connected to an X-direction servo accelerometer 10, a Y-direction servo accelerometer 11, a Z-direction servo accelerometer 12, a pitch direction inclinometer 13, and rolls. DA conversion connected to direction inclinometer (14) bow angle (Yaw), azimuth (15), thermometer (16), pressure gauge (17) (8) is connected to the six degrees of freedom motion signal (X, Y, Z, longitudinal inclination, transverse inclination, bow angle inclination) and the digital signal input (9) is the altitude son (via the digital input port 19) ( 18. 6 degrees of freedom motion measurement and position measuring device for marine and subsea moving hulls.