Offshore oil and gas drilling platform attitude control method and system based on inertial navigation

Abstract

The invention provides an offshore oil and gas drilling platform attitude control method based on inertial navigation. The method comprises the following steps: acquiring original motion data of a drilling platform through an inertial navigation system and a global navigation satellite system; performing data fusion on the measurement data of the inertial navigation system and the global navigation satellite system, estimating the current motion state of the drilling platform in real time, comparing the estimated current motion state with a preset expected motion state to obtain a motion state error, and obtaining an optimal thrust instruction of each propeller of the platform; and the optimal thrust instruction is sent to an execution mechanism of each propeller so as to drive the propellers to generate corresponding thrust and torque, and the posture and the position of the drilling platform are actively controlled. Based on the high-precision state estimation, the control system can find the tiny deviation of platform movement earlier and more accurately and respond quickly, so that the posture and the position of the platform are stabilized in a smaller error range.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of marine engineering or automatic control technology, in particular to a marine oil and gas drilling platform attitude control method and system based on inertial navigation. BACKGROUND

[0002] The marine oil and gas drilling platform is a key equipment for offshore oil and gas exploration and development. During operation, the platform will be continuously disturbed by complex marine environmental forces such as wind, wave and current, resulting in six degrees of freedom motion of roll, pitch, yaw, heave, surge and sway. In particular, excessive horizontal displacement of surge and sway and attitude angles of roll and pitch will seriously affect the safety and efficiency of drilling operations, possibly leading to drilling riser stress exceeding the standard, drilling tool damage, and even serious well control safety accidents.

[0003] In order to suppress platform motion, modern drilling platforms are usually equipped with dynamic positioning systems and attitude control systems. Early control systems rely on DGPS, underwater positioning systems and vertical motion reference units, and the core is to control the horizontal position and heading of the platform. However, such systems have obvious limitations: first, for high-frequency and small-amplitude roll and pitch attitude motion of the platform, the measurement accuracy and update frequency of traditional sensors are insufficient, resulting in control system response lag and poor stability effect; second, the system usually adopts a simple feedback control strategy, which cannot compensate in advance for rapid changes in environmental disturbances such as wind, resulting in poor dynamic performance.

[0004] Inertial navigation system (INS) can provide high-frequency and high-precision full-attitude information, which is theoretically very suitable for attitude control. However, the navigation error of INS will drift with time and needs to be effectively fused with other sensors to provide a long-term reliable attitude reference.

[0005] Therefore, there is an urgent need in the art for a high-precision and high-response speed drilling platform attitude control method and system based on inertial navigation that can overcome the above-mentioned shortcomings. SUMMARY

[0006] To solve the above technical problems, the technical solution adopted by the present application is as follows:

[0007] According to one aspect of the present application, a marine oil and gas drilling platform attitude control method based on inertial navigation is provided, comprising the following steps:

[0008] Step S1: Collecting raw motion data of the drilling platform through an inertial navigation system and a global navigation satellite system;

[0009] Step S2: data fusion is performed on the measurement data of the inertial navigation system and the global navigation satellite system by using a Kalman filter, and a current motion state of the drilling platform is estimated in real time, the current motion state including position, velocity, roll angle, pitch angle, and heading angle;

[0010] Step S3: the current motion state estimated in step S2 is compared with a preset expected motion state, a motion state error is obtained, and total control force and total control moment required for stabilizing the platform are calculated by a feedback-feedforward controller in combination with feedforward environmental wind data;

[0011] Step S4: based on the total control force and the total control moment calculated in step S3, optimal thrust instructions of the propellers of the platform are solved by a thrust distribution algorithm;

[0012] Step S5: the optimal thrust instructions are sent to the actuators of the propellers, so that the propellers generate corresponding thrust and moment, and the attitude and position of the drilling platform are actively controlled.

[0013] In step S2, the Kalman filter is an extended Kalman filter or an unscented Kalman filter; and the specific process of the data fusion includes:

[0014] The specific process of the data fusion includes:

[0015] The specific process of the data fusion includes:

[0016] In step S3, the feedback-feedforward controller adopts a PID control law; and the environmental wind data for feedforward control are measured by a wind speed and direction instrument installed on the platform.

[0017] In step S2, the estimated motion state further includes the sway, surge, and heave motions of the platform.

[0018] A marine oil and gas drilling platform attitude control system based on inertial navigation for implementing the above method, comprising:

[0019] A data sensing module including an inertial navigation system and a global navigation satellite system, configured to collect original motion data of the drilling platform;

[0020] The central processing module is configured to perform the following operations: perform data fusion on the raw motion data to estimate the current motion state of the drilling platform in real time; calculate the required total control force and total control torque based on the error between the current motion state and the preset desired motion state and the feedforward environmental wind data; and solve for the optimal thrust command for each thruster of the platform through a thrust distribution algorithm.

[0021] The execution module includes multiple azimuth thrusters, which receive the optimal thrust command and execute the thrust action;

[0022] The human-computer interaction module is used to collect preset desired motion state parameters and display the real-time operating status of the system.

[0023] The data sensing module further includes an anemometer and a vertical motion reference unit. The anemometer is used to provide the environmental parameters required for feedforward control, and the vertical motion reference unit is used to perform redundancy verification on the roll and pitch angles estimated by the inertial navigation system and the global navigation satellite system.

[0024] The data sensing module communicates with the central processing module via Ethernet or CAN bus.

[0025] It also includes a sensor redundancy unit, which comprises at least two independent inertial navigation systems and a global navigation satellite system combined navigation system.

[0026] According to another aspect of this application, a non-transitory computer-readable storage medium is provided, wherein at least one instruction or at least one program is stored in the storage medium, the at least one instruction or the at least one program being loaded and executed by a processor to implement the aforementioned attitude control method for offshore oil and gas drilling platforms based on inertial navigation.

[0027] According to another aspect of this application, an electronic device is provided, including a processor and the aforementioned non-transitory computer-readable storage medium.

[0028] This invention offers the following advantages: By tightly coupling data fusion between an inertial navigation system and a global navigation satellite system, it obtains high-frequency, high-precision full-attitude information of the platform, including position, velocity, roll, pitch, and heading, reaching frequencies above 100Hz. This provides the control system with perception capabilities far exceeding traditional solutions. Based on this high-precision state estimation, the control system can detect minute deviations in the platform's motion earlier and more accurately, and respond quickly, thereby stabilizing the platform's attitude and position within a smaller error range. Attached Figure Description

[0029] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the following will briefly introduce the drawings needed in the embodiments description. Obviously, the drawings in the following description only show some embodiments of the present application, and all other drawings obtained by those skilled in the art without creative effort based on these drawings also belong to the protection scope of the present application.

[0030] Figure 1 The flow chart of the marine oil and gas drilling platform attitude control method based on inertial navigation provided by the embodiments of the present application. DETAILED DESCRIPTION

[0031] The technical solutions in the embodiments of the present application will be clearly and completely described in the following with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only some embodiments of the present application, but not all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative effort also belong to the protection scope of the present application.

[0032] As shown in Figure 1 a marine oil and gas drilling platform attitude control method based on inertial navigation, comprising the following specific steps:

[0033] Step S1: collecting original motion data of the drilling platform by an inertial navigation system and a global navigation satellite system.

[0034] Specifically, the inertial navigation system adopts a high-precision inertial measurement unit, for example, an optical fiber gyroscope. The inertial navigation system is fixedly installed on a rigid structure of the drilling platform close to the center of gravity of the drilling platform to minimize the measurement error caused by structural deformation. The global navigation satellite system preferably adopts a dual-antenna receiver supporting real-time dynamic differential technology. Before the platform operation, the installation deviation angle between the inertial navigation system and the drilling platform coordinate system needs to be calibrated and compensated in subsequent data processing. In this step, the inertial navigation system provides high-frequency angular velocity and specific force data above 100 Hz. The global navigation satellite system provides low-frequency but higher-precision absolute position, velocity and heading angle information.

[0035] Step S2: using a Kalman filter to fuse the measurement data of the inertial navigation system and the global navigation satellite system to estimate the current motion state of the drilling platform in real time.

[0036] The current motion state at least includes position, velocity, roll angle, pitch angle and heading angle. Preferably, the motion state also includes the sway, surge and heave motion of the drilling platform, so as to obtain complete six-degree-of-freedom motion information.

[0037] Specifically, the Kalman filter is preferably an Extended Kalman Filter (EKF) or an Unscented Kalman Filter (UKF) to handle the nonlinear characteristics of the platform motion. The data fusion is performed cyclically in a central processing module according to the following process:

[0038] State prediction: Using the specific force and angular velocity output by the inertial navigation system as input to the system model (i.e., the platform kinematic equations), state prediction is performed; the motion state of the drilling platform at the next moment is predicted.

[0039] Measurement Update: Using the position and velocity information measured by the Global Navigation Satellite System (GNSS) as the first measurement value, and the high-precision heading angle information obtained by baseline calculation from the dual antennas of the GNSS as the second measurement value, the predicted state is optimally corrected. This not only outputs high-frequency, high-precision full-attitude data, but more importantly, it can estimate and compensate for the zero-bias errors of the gyroscopes and accelerometers in the inertial navigation system in real time. This effectively suppresses the inherent drift error accumulated over time in the inertial navigation system, providing a long-term reliable state reference for the control system.

[0040] Step S3: Compare the current motion state estimated in step S2 with the preset expected motion state to obtain the motion state error. Combined with the feedforward environmental wind data, calculate the total control force and total control torque required for stabilizing the platform through the feedback-feedforward controller.

[0041] Specifically, the preset desired motion state is set by the operator through the human-machine interface module, and typically includes the target position coordinates and the desired heading angle. The motion state error is the difference between the current value and the desired value. The feedback-feedforward controller uses the classic PID control law as its feedback control part. For example, independent position PID controllers and heading PID controllers are designed to calculate the preliminary feedback control force and torque based on the position error and heading error, respectively.

[0042] The environmental wind data for the feedforward control is obtained in real time by an anemometer installed on the mast at a high position on the drilling platform.

[0043] The attitude control system incorporates a wind load model, calculating the disturbance force and torque generated by the current wind acting on the platform hull based on measured wind speed and direction. The feedforward control directly generates a control command equal in magnitude and opposite in direction to the wind disturbance force. The final total control force and torque are obtained by adding the feedback control output and the feedforward control output. This allows the system to actively counteract major environmental disturbances, rather than responding passively, significantly improving the system's anti-interference capability and dynamic response speed.

[0044] Step S4: Based on the total control force and total control torque calculated in step S3, the optimal thrust command for each thruster of the platform is solved by the thrust distribution algorithm.

[0045] Specifically, multiple azimuth thrusters are configured at the bottom or around the perimeter of the platform. The thrust distribution algorithm is existing technology, and those skilled in the art can select one based on the actual situation. This algorithm is essentially a constrained optimization problem. First, the algorithm establishes a mapping relationship (i.e., thrust distribution matrix) between the thrust of each thruster and the resultant force / torque acting on the platform as a whole, based on the installation position and angle of each thruster. Then, with the objective of minimizing total energy consumption or maximizing thrust margin, and using the upper limit of thrust and angular velocity limits for each thruster as constraints, optimization algorithms such as quadratic programming are used to calculate the optimal thrust magnitude and direction command for each thruster, thus achieving optimized allocation of control resources.

[0046] Step S5: Send the optimal thrust command to the actuator of each thruster to drive the thrusters to generate corresponding thrust and torque, and actively control the attitude and position of the drilling platform.

[0047] Specifically, the optimal thrust command is sent to the local controller of each thruster via Ethernet or CAN bus. The thrusters adjust the propeller speed and rudder angle according to the command, thereby generating precise thrust and torque, which work together to counteract environmental interference and ultimately stabilize the rolling, pitching, and heading attitude and position of the drilling platform within the allowable error range, ensuring the safety of drilling operations.

[0048] An attitude control system for an offshore oil and gas drilling platform based on inertial navigation for implementing the above method includes:

[0049] The data sensing module, including an inertial navigation system and a global navigation satellite system, is used to collect raw motion data of the drilling platform.

[0050] The central processing module performs data fusion on the raw motion data to estimate the current motion state of the drilling platform in real time; based on the error between the current motion state and the preset expected motion state and the feedforward environmental wind data, it calculates the required total control force and total control torque; and solves for the optimal thrust command of each thruster of the platform through a thrust distribution algorithm.

[0051] The execution module includes multiple azimuth thrusters, which receive the optimal thrust command and execute the thrust action.

[0052] The human-machine interface (HMI) module is used to collect preset desired motion state parameters and display the real-time operating status of the system. The HMI module typically includes one or more workstations, providing a graphical interface that allows operators to set target points, select control modes such as automatic positioning and head-hold, and monitor the platform's attitude, position, thruster status, environmental parameters, and system alarm information in real time.

[0053] In a preferred embodiment, the data sensing module further includes an anemometer and a vertical motion reference unit. The anemometer provides the environmental parameters required for feedforward control. The vertical motion reference unit is an existing, mature attitude sensor that provides roll and pitch angle data for real-time comparison and redundancy verification with the roll and pitch angles estimated by the inertial navigation system and the global navigation satellite system. When the difference between the two exceeds a preset threshold, an alarm is issued, indicating a possible sensor malfunction, which greatly enhances the reliability of the system.

[0054] Furthermore, the data sensing module and the central processing module are connected via a high-speed, reliable industrial communication bus, such as Ethernet or CAN bus.

[0055] To meet the high safety requirements of marine operations, the system of this invention also includes a sensor redundancy unit. This sensor redundancy unit comprises at least two independent inertial navigation systems and a global navigation satellite system (GNSS) integrated navigation system. Multiple inertial navigation systems and the GNSS integrated navigation system operate simultaneously. The central processing module uses a "voting" or "optimal value selection" algorithm to process the output data from multiple systems. When the primary system data is abnormal, it can seamlessly switch to the backup system, thus forming a fault-tolerant and highly reliable system.

[0056] Embodiments of the present invention also provide a computer program product including program code, which, when the program product is run on an electronic device, causes the electronic device to perform the steps of the methods described above in various exemplary embodiments of the present invention.

[0057] Furthermore, although the steps of the method in this disclosure are described in a specific order in the accompanying drawings, this does not require or imply that the steps must be performed in that specific order, or that all the steps shown must be performed to achieve the desired result. Additional or alternative steps may be omitted, multiple steps may be combined into one step, and / or a step may be broken down into multiple steps.

[0058] From the above description of the embodiments, those skilled in the art will readily understand that the exemplary embodiments described herein can be implemented by software or by combining software with necessary hardware. Therefore, the technical solutions according to the embodiments of this disclosure can be embodied in the form of a software product, which can be stored in a non-volatile storage medium (such as a CD-ROM, USB flash drive, external hard drive, etc.) or on a network, including several instructions to cause a computing device (such as a personal computer, server, mobile terminal, or network device, etc.) to execute the method according to the embodiments of this disclosure.

[0059] In an exemplary embodiment of this disclosure, an electronic device capable of implementing the above-described method is also provided.

[0060] Those skilled in the art will understand that various aspects of the present invention can be implemented as systems, methods, or program products. Therefore, various aspects of the present invention can be specifically implemented in the following forms: entirely hardware implementations, entirely software implementations (including firmware, microcode, etc.), or implementations combining hardware and software aspects, collectively referred to herein as “circuits,” “modules,” or “systems.”

[0061] An electronic device according to this embodiment of the invention. The electronic device is merely an example and should not be construed as limiting the functionality or scope of the embodiments of the invention.

[0062] Electronic devices are manifested in the form of general-purpose computing devices. Components of an electronic device may include, but are not limited to: at least one processor, at least one memory, and buses connecting different system components (including memory and processor).

[0063] The storage device stores program code that can be executed by the processor to perform the steps described in the "Exemplary Methods" section above, according to various exemplary embodiments of the present invention.

[0064] The storage may include readable media in the form of volatile storage, such as random access memory (RAM) and / or cache memory, and may further include read-only memory (ROM).

[0065] The storage may also include programs / utilities having a set (at least one) of program modules, including but not limited to: an operating system, one or more applications, other program modules, and program data, each or some combination of these examples may include an implementation of a network environment.

[0066] A bus can represent one or more of several bus architectures, including a memory bus or memory controller, a peripheral bus, a graphics acceleration port, a processor, or a local bus that uses any of the various bus architectures.

[0067] Electronic devices can also communicate with one or more external devices (such as keyboards, pointing devices, Bluetooth devices, etc.), one or more devices that enable users to interact with the electronic device, and / or any device that enables the electronic device to communicate with one or more other computing devices (such as routers, modems, etc.). This communication can be performed through input / output (I / O) interfaces. Furthermore, electronic devices can also communicate with one or more networks (such as local area networks (LANs), wide area networks (WANs), and / or public networks, such as the Internet) via network adapters.

[0068] In exemplary embodiments of this disclosure, a computer-readable storage medium is also provided, on which a program product capable of implementing the methods described above is stored. In some possible embodiments, various aspects of the invention may also be implemented as a program product comprising program code that, when the program product is run on a terminal device, causes the terminal device to perform the steps of the various exemplary embodiments of the invention described in the "Exemplary Methods" section of this specification.

[0069] The program product may employ any combination of one or more readable media. A readable medium may be a readable signal medium or a readable storage medium. A readable storage medium may be, for example, but not limited to, an electrical, magnetic, optical, electromagnetic, infrared, or semiconductor system, apparatus, or device, or any combination thereof. More specific examples of readable storage media (a non-exhaustive list) include: an electrical connection having one or more wires, a portable disk, a hard disk, random access memory (RAM), read-only memory (ROM), erasable programmable read-only memory (EPROM or flash memory), optical fiber, portable compact disk read-only memory (CD-ROM), optical storage devices, magnetic storage devices, or any suitable combination thereof.

[0070] Computer-readable signal media may include data signals propagated in baseband or as part of a carrier wave, carrying readable program code. Such propagated data signals may take various forms, including but not limited to electromagnetic signals, optical signals, or any suitable combination thereof. A readable signal medium may also be any readable medium other than a readable storage medium, capable of sending, propagating, or transmitting programs for use by or in conjunction with an instruction execution system, apparatus, or device.

[0071] The program code contained on the readable medium may be transmitted using any suitable medium, including but not limited to wireless, wired, optical fiber, RF, etc., or any suitable combination thereof.

[0072] Program code for performing the operations of this invention can be written in any combination of one or more programming languages, including object-oriented programming languages ​​such as Java and C++, and conventional procedural programming languages ​​such as C or similar languages. The program code can execute entirely on the user's computing device, partially on the user's device, as a standalone software package, partially on the user's computing device and partially on a remote computing device, or entirely on a remote computing device or server. In cases involving remote computing devices, the remote computing device can be connected to the user's computing device via any type of network, including a local area network (LAN) or a wide area network (WAN), or it can be connected to an external computing device (e.g., via the Internet using an Internet service provider).

[0073] Furthermore, the above figures are merely illustrative of the processes included in the method according to exemplary embodiments of the present invention, and are not intended to be limiting. It is readily understood that the processes shown in the above figures do not indicate or limit the temporal order of these processes. Additionally, it is readily understood that these processes may be executed synchronously or asynchronously, for example, in multiple modules.

[0074] It should be noted that although several modules or units for the device used to perform actions have been mentioned in the detailed description above, this division is not mandatory. In fact, according to embodiments of this disclosure, the features and functions of two or more modules or units described above can be embodied in one module or unit. Conversely, the features and functions of one module or unit described above can be further divided and embodied by multiple modules or units.

[0075] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A method for attitude control of an offshore oil and gas drilling platform based on inertial navigation, characterized in that, Includes the following steps: Step S1: Collect raw motion data of the drilling platform using an inertial navigation system and a global navigation satellite system; Step S2: Use a Kalman filter to fuse the measurement data from the inertial navigation system and the global navigation satellite system to estimate the current motion state of the drilling platform in real time. The current motion state includes position, velocity, roll angle, pitch angle, and heading angle. Step S3: Compare the current motion state estimated in step S2 with the preset expected motion state to obtain the motion state error, and combine it with the feedforward environmental wind data to calculate the total control force and total control torque required for stabilizing the platform through the feedback-feedforward controller; Step S4: Based on the total control force and total control torque calculated in step S3, the optimal thrust command for each thruster of the platform is solved using the thrust distribution algorithm; Step S5: Send the optimal thrust command to the actuator of each thruster to drive the thrusters to generate corresponding thrust and torque, and actively control the attitude and position of the drilling platform.

2. The method according to claim 1, characterized in that, In step S2, the Kalman filter is an extended Kalman filter or an unscented Kalman filter; the specific process of data fusion includes: The specific force and angular velocity output by the inertial navigation system are used as inputs to the system model for state prediction. The predicted state is updated using position and velocity information measured by the Global Navigation Satellite System (GNSS) and heading angle information measured by the dual antennas of the GNSS.

3. The method according to claim 1, characterized in that, In step S3, the feedback-feedforward controller adopts a PID control law; the environmental wind force data for feedforward control is obtained by measuring the anemometer and wind direction installed on the platform.

4. The method according to claim 1, characterized in that, The motion states estimated in step S2 also include the platform's sway, undulation, and heave motions.

5. An attitude control system for an offshore oil and gas drilling platform based on inertial navigation for implementing the method of any one of claims 1-4, characterized in that, include: The data sensing module, including an inertial navigation system and a global navigation satellite system, is used to collect raw motion data of the drilling platform; The central processing module is configured to perform the following operations: perform data fusion on the raw motion data to estimate the current motion state of the drilling platform in real time; Based on the error between the current motion state and the preset desired motion state, and the feedforward environmental wind data, the required total control force and total control torque are calculated; the optimal thrust command for each thruster of the platform is solved by the thrust distribution algorithm. The execution module includes multiple azimuth thrusters, which receive the optimal thrust command and execute the thrust action; The human-computer interaction module is used to collect preset desired motion state parameters and display the real-time operating status of the system.

6. The system according to claim 5, characterized in that, The data sensing module also includes an anemometer and a vertical motion reference unit. The anemometer is used to provide the environmental parameters required for feedforward control, and the vertical motion reference unit is used to perform redundancy verification on the roll and pitch angles estimated by the inertial navigation system and the global navigation satellite system.

7. The system according to claim 6, characterized in that, The data sensing module communicates with the central processing module via Ethernet or CAN bus.

8. The system according to claim 6 or 7, characterized in that, Also includes: The sensor redundancy unit includes at least two independent inertial navigation systems and a global navigation satellite system combined navigation system.

9. A non-transitory computer-readable storage medium, characterized in that, The storage medium stores at least one instruction or at least one program segment, which is loaded and executed by a processor to implement the method as described in any one of claims 1-4.

10. An electronic device, characterized in that, Includes a processor and the non-transitory computer-readable storage medium as described in claim 9.

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