Fuzzy PID angle control method for cylindrical coordinate manipulator of drilling machine

Abstract

The invention discloses a fuzzy PID angle control method for a cylindrical coordinate manipulator of a drilling machine. The method comprises the following steps: constructing a hydraulic model of a rotary mechanism of the cylindrical coordinate manipulator of a submarine drilling machine; according to the hydraulic model of the cylindrical coordinate manipulator slewing mechanism of the seabed drilling machine, constructing a hydraulic motor control model of the cylindrical coordinate manipulator of the seabed drilling machine; a given input signal is input into the seabed drilling machine cylindrical coordinate manipulator hydraulic motor control model, and a current angle output value is obtained; and parameters of PID control are adaptively adjusted according to the fuzzy rule, so that the current angle output value better tracks the given value, and adjustment control over the angle of the manipulator is achieved. Fuzzy control is introduced, PID parameters are adjusted in real time according to the angle feedback error and the change rate of the angle feedback error, external interference is responded more quickly, the dynamic response characteristic of the system is improved, and finer manipulator angle control is achieved, so that the overall control precision is improved, and the system is more suitable for the complex marine environment.

Description

Technical Field

[0001] The present invention belongs to the technical field of the angle control strategy of the cylindrical coordinate manipulator of a drilling rig, and particularly relates to a fuzzy PID angle control method for the cylindrical coordinate manipulator of a subsea drilling rig. Background Art

[0002] Deep-sea subsea drilling rigs are important technical equipment for marine scientific research and the exploration and development of marine resources, and are currently the main technical means for deep-sea subsurface geological sampling and exploration. Accurate and comprehensive deep-sea samples and data can be obtained through subsea drilling rigs, providing a scientific basis for resource exploration and development. Subsea drilling rigs usually operate at depths of several thousand meters below the sea surface. The communication system is responsible for transmitting control signals, and the automatic control system on the water surface controls the drilling rig to complete a series of actions and work objectives, which has high integration and complexity.

[0003] As a key component in the subsea drilling rig system, the manipulator can perform complex operations in a narrow space with its flexible joint structure and precise control ability, thus ensuring the accuracy of the drilling work. The manipulator can simulate the actions of a human hand to complete tasks such as grasping, transporting, and installing drill pipes, enabling the subsea drilling rig to maintain an efficient operating state. The drill pipes and drilling tools of the subsea drilling rig are arranged in a cylindrical shape, which has a good fit with the cylindrical coordinate manipulator. The cylindrical coordinate manipulator consists of rotational and translational joints and has a cylindrical working space. In these operations, angle control is crucial for the performance of the cylindrical coordinate manipulator of the subsea drilling rig. Angle control enables the manipulator to accurately grasp, place, and rotate drill pipes and drilling tools, realizing the connection, unloading, lowering, and recovery of drill pipes and drilling tools, and improving the success rate and efficiency of the operation.

[0004] Currently, traditional PID control is mostly used for the angle control of subsea drilling rig manipulators. The subsea environment is complex and changeable with many interference factors. Traditional PID control has poor environmental adaptability and weak anti-interference ability, and cannot respond quickly to adapt to the changing operation requirements, affecting the control effect. Summary of the Invention

[0005] To solve the above technical problems, the present invention proposes a fuzzy PID angle control method for the cylindrical coordinate manipulator of a drilling rig. Based on the traditional PID angle control, fuzzy control is introduced to adjust the parameters of PID in real time according to the error of the angle feedback and its change rate, respond more quickly to external interference, improve the dynamic response characteristics of the system, realize more precise manipulator angle control, thereby improving the overall control accuracy and making it more adaptable to the complex marine environment.

[0006] The present invention provides a fuzzy PID angle control method for the cylindrical coordinate manipulator of a drilling rig, including:

[0007] Build a hydraulic model for the rotary mechanism of the cylindrical coordinate manipulator of the subsea drill rig;

[0008] Build a hydraulic motor control model for the cylindrical coordinate manipulator of the subsea drill rig according to the hydraulic model of the rotary mechanism of the cylindrical coordinate manipulator of the subsea drill rig;

[0009] Input a given input signal into the hydraulic motor control model of the cylindrical coordinate manipulator of the subsea drill rig to obtain the current angle output value;

[0010] Adjust the parameters of the PID control adaptively according to the fuzzy rules so that the current angle output value can better track the given value, realizing the adjustment control of the manipulator angle.

[0011] Optionally, the hydraulic model of the rotary mechanism of the cylindrical coordinate manipulator of the subsea drill rig includes: an electric motor, a hydraulic pump, a pressure compensator, a proportional direction valve, a relief valve, and a hydraulic motor.

[0012] Optionally, the hydraulic motor model of the cylindrical coordinate manipulator of the subsea drill rig includes: a controller module, a proportional amplification module, an electro-hydraulic proportional valve module, a hydraulic motor module, an execution module, and a detection and feedback module.

[0013] Optionally, building the hydraulic motor model of the cylindrical coordinate manipulator of the subsea drill rig includes:

[0014] Obtain the transfer function of the proportional amplification module;

[0015] Obtain the transfer function of the electro-hydraulic proportional valve module;

[0016] Obtain the spool displacement of the electro-hydraulic proportional valve module, and combine with the external load disturbance to obtain the angular displacement of the hydraulic motor;

[0017] According to the angular displacement, obtain the transfer function of the angular displacement to the spool displacement and the transfer function of the angular displacement to the external load torque;

[0018] According to the transfer function of the proportional amplification module, the transfer function of the electro-hydraulic proportional valve module, the transfer function of the angular displacement to the spool displacement, and the transfer function of the angular displacement to the external load torque, obtain the total transfer function;

[0019] According to the total transfer function, obtain the hydraulic motor control model of the cylindrical coordinate manipulator of the subsea drill rig.

[0020] Optionally, the method for obtaining the transfer function of the proportional amplification module is:

[0021]

[0022] where U(s) is the input voltage of the proportional amplifier, I(s) is the input current of the proportional amplifier, K ais the proportional amplifier coefficient;

[0023] The method for obtaining the transfer function of the electro-hydraulic proportional valve module is:

[0024]

[0025] where X v is the spool displacement of the proportional valve, I is the input current of the electromagnet, s is the Laplace operator, and K sv is the displacement gain of the proportional valve, ω sv is the natural frequency of the proportional valve, and ζ sv is the damping ratio of the proportional valve;

[0026] The method for obtaining the angular displacement of the hydraulic motor is:

[0027]

[0028] where D m is the displacement of the hydraulic motor, θ m is the rotation angle of the hydraulic motor, Kq is the flow gain of the proportional valve, and β e is the effective bulk modulus of the working fluid, T L is the external load torque, V t is the total volume of the hydraulic motor and its pipelines, J t is the total moment of inertia of the hydraulic motor and the load, B m is the viscous damping coefficient, ω h is the hydraulic natural frequency, and ξ h is the hydraulic damping coefficient, and K ce is the total flow rate of the hydraulic motor;

[0029] The method for obtaining the transfer function of the angular displacement with respect to the spool displacement is:

[0030]

[0031] where θ m (s) is the angular displacement, and X v (s) is the spool displacement;

[0032] The method for obtaining the transfer function of the angular displacement with respect to the external load torque is:

[0033]

[0034] where T L (s) is the external load torque;

[0035] The method for obtaining the total transfer function is:

[0036]

[0037] Among them, G(s) is the total transfer function, and U f (s) is the feedback signal, and U e (s) is the error signal.

[0038] Optionally, controlling the current angle output value by using the manipulator fuzzy PID angle control method includes:

[0039] Obtaining the deviation and deviation rate between the current angle output value and the given angle;

[0040] Performing fuzzy processing on the deviation and deviation rate, and combining with the fuzzy rule base to obtain a correction coefficient;

[0041] Performing defuzzification processing on the correction coefficient, and combining with the initial control parameters to obtain the final control parameters;

[0042] Controlling the current angle output value by using the final control parameters.

[0043] Optionally, the method for the control parameters is:

[0044]

[0045] Among them, K P 、K I 、K D are respectively the final control parameters of the PID controller, k p 、k i 、k d are respectively the initial control parameters of the PID controller, and ΔK P 、ΔK I and ΔK D are respectively the parameter increments output by the fuzzy controller.

[0046] Compared with the prior art, the present invention has the following advantages and technical effects:

[0047] Based on the traditional PID angle control, the present invention introduces fuzzy control to adjust the parameters of the PID in real time according to the error of the angle feedback and its change rate, responds to external interference faster, improves the dynamic response characteristics of the system, realizes more precise manipulator angle control, thereby improving the overall control accuracy and making it more adaptable to complex marine environments.

[0048] For the cylindrical coordinate manipulator of the subsea drilling rig operating in a relatively harsh environment, the adjustment time of the fuzzy PID control of the present invention is shorter, and it has better stability in the case of large changes in the manipulator angle and torque. In addition, the response speed can be adaptively adjusted according to the magnitude of the angle change, that is, when the angle deviation is large, the speed is fast; when the angle deviation is small, the speed is slow. Description of the Drawings

[0049] The accompanying drawings, which form a part of this application, are used to provide a further understanding of this application. The schematic embodiments of this application and their descriptions are used to explain this application and do not constitute an improper limitation to this application. In the accompanying drawings:

[0050] Figure 1 is a flowchart of a fuzzy PID angle control method for a drilling rig cylindrical coordinate manipulator according to an embodiment of the present invention;

[0051] Figure 2 is a three-dimensional view of a subsea drilling rig cylindrical coordinate manipulator according to an embodiment of the present invention;

[0052] Figure 3 is a schematic diagram of an equivalent simplified model of a manipulator according to an embodiment of the present invention;

[0053] Figure 4 is a schematic diagram of the control of a manipulator hydraulic system according to an embodiment of the present invention;

[0054] Figure 5 is a control block diagram of a hydraulic motor according to an embodiment of the present invention;

[0055] Figure 6 is a transfer function block diagram of a hydraulic motor system according to an embodiment of the present invention;

[0056] Figure 7 is an angle control transfer function block diagram of a hydraulic motor system according to an embodiment of the present invention;

[0057] Figure 8 is a fuzzy control structure diagram according to an embodiment of the present invention;

[0058] Figure 9 is a fuzzy PID control structure diagram according to an embodiment of the present invention;

[0059] Figure 10 is a membership function diagram of the deviation e according to an embodiment of the present invention;

[0060] Figure 11 is a membership function diagram of the deviation change rate ec according to an embodiment of the present invention;

[0061] Figure 12 is a membership function diagram of the deviation ΔK P according to an embodiment of the present invention;

[0062] Figure 13 is a membership function diagram of the deviation ΔK I according to an embodiment of the present invention;

[0063] Figure 14 is a membership function diagram of the deviation ΔK D according to an embodiment of the present invention;

[0064] Figure 15It is the input / output surface view of the embodiment of the present invention;

[0065] Figure 16 It is the simulation structure diagram of each part of the hybrid energy storage model predictive overall control method of the embodiment of the present invention;

[0066] Figure 17 It is the simulation structure diagram of each part of the PI control method of the hybrid energy storage system of the embodiment of the present invention;

[0067] Figure 18 It is the simulation structure diagram of each part of the PI control method of the hybrid energy storage system under the first working condition of the embodiment of the present invention;

[0068] Figure 19 It is the simulation structure diagram of each part of the PI control method of the hybrid energy storage system under the second working condition of the embodiment of the present invention;

[0069] Figure 20 It is the comparison diagram of voltage fluctuations between PI control and model predictive overall control under the third working condition of the embodiment of the present invention. Specific implementation manners

[0070] It should be noted that, without conflict, the embodiments in the present application and the features in the embodiments can be combined with each other. The present application will be described in detail below with reference to the drawings and in combination with the embodiments.

[0071] It should be noted that the steps shown in the flowchart of the drawings can be executed in a computer system such as a set of computer-executable instructions, and although the logical order is shown in the flowchart, in some cases, the steps shown or described can be executed in a different order than here.

[0072] The present invention proposes a fuzzy PID angle control method for a drilling rig cylindrical coordinate manipulator, as Figure 1 shown, which specifically includes the following steps:

[0073] Construct a hydraulic model of the rotary mechanism of the subsea drilling rig cylindrical coordinate manipulator;

[0074] According to the hydraulic model of the rotary mechanism of the subsea drilling rig cylindrical coordinate manipulator, construct a hydraulic motor model of the subsea drilling rig cylindrical coordinate manipulator;

[0075] Input a preset voltage value into the hydraulic motor model of the subsea drilling rig cylindrical coordinate manipulator to obtain the current angle output value;

[0076] According to the fuzzy rules, adaptively adjust the parameters of the PID to reduce the difference between the current angle output value and the given angle, and realize the adjustment and control of the manipulator angle.

[0077] Specifically, the formulation of fuzzy rules is usually based on engineering experiments and empirical summaries to establish a suitable fuzzy rule base. The main principles are as follows:

[0078] The deviation e refers to the difference between the current angle and the set angle; the change rate of the deviation ec reflects the changing trend of the deviation over time, that is, the changing speed of the gap between the current angle and the set angle. Through this value, the change of the future deviation can be predicted. For example, when ec is large, it indicates that the system is quickly approaching or moving away from the set point. When ec is small or close to zero, it indicates that the system may have approached a stable state.

[0079] Furthermore, the hydraulic model of the rotary mechanism of the cylindrical coordinate manipulator of the subsea drill rig includes: an electric motor, a hydraulic pump, a pressure compensator, a proportional direction valve, a relief valve, and a hydraulic motor.

[0080] Specifically, the cylindrical coordinate manipulator of the subsea drill rig is an important component for the subsea drill rig to complete the grasping and drilling actions of drill pipes and drilling tools. The three-dimensional model is as Figure 2 shown, and the abstract simplified structure diagram is as Figure 3 shown. It has three degrees of freedom and four actions, namely rotation, telescoping, vertical movement, and the closing and releasing of the gripper. The rotation function is realized by driving a hydraulic motor controlled by an electro-hydraulic valve, and the angle ranges from 0 to 360 degrees. The vertical and telescoping movements are realized by hydraulic cylinders. Among the actions realized by the manipulator, the rotation action is one of the most important actions. The accuracy of the rotation angle determines whether the subsequent coherent actions can be carried out normally.

[0081] The hydraulic system and its control of the rotary mechanism of the manipulator are as Figure 4 shown. This system mainly consists of an electric motor, a hydraulic pump, a pressure compensator, a proportional direction valve, a relief valve, and a hydraulic motor. The working principle of this system is as follows: By controlling the opening of the proportional valve through the input signal, the amount of oil flowing through the hydraulic motor is adjusted, thereby achieving precise control of the speed and rotation direction of the hydraulic motor. The control strategy adopts a position feedback closed-loop system. This system continuously detects and feeds back position data through sensors. If a deviation is detected between the set position and the actual position, the system will adjust through solenoid valves and actuators. In addition, due to the limited volume of the oil tank of the underwater hydraulic system, the system is equipped with a pressure compensator to automatically adjust the ambient pressure at different depths and compensate in real time for the oil volume changes caused by oil elasticity, temperature changes, or flow differences during the operation of asymmetric cylinders.

[0082] Furthermore, the hydraulic motor model of the cylindrical coordinate manipulator of the subsea drill rig includes: a controller module, a proportional amplification module, an electro-hydraulic proportional valve module, a hydraulic motor module, an execution module, and a detection and feedback module.

[0083] Specifically, the rotary hydraulic system of the cylindrical coordinate manipulator of the subsea drill rig is a complex system composed of several hydraulic components. This complex system can be equivalent to multiple standard links. By analyzing the transfer functions of these standard links, the equivalent model of the entire system can be obtained. The structure of the manipulator control system is as shown in Figure 5 Figure Figure 5 , which mainly includes a controller link, a proportional amplification link, an electro-hydraulic proportional valve link, a hydraulic motor link, an actuator link, and a detection and feedback link.

[0084] Furthermore, the construction of the hydraulic motor model of the cylindrical coordinate manipulator of the subsea drill rig includes:

[0085] Obtain the transfer function of the proportional amplification module;

[0086] Obtain the transfer function of the electro-hydraulic proportional valve module;

[0087] Obtain the spool displacement of the electro-hydraulic proportional valve module, and combine with the external load disturbance to obtain the angular displacement of the hydraulic motor;

[0088] According to the angular displacement, obtain the transfer function of the angular displacement to the spool displacement and the transfer function of the angular displacement to the external load torque;

[0089] According to the transfer function of the proportional amplification module, the transfer function of the electro-hydraulic proportional valve module, the transfer function of the angular displacement to the spool displacement, and the transfer function of the angular displacement to the external load torque, obtain the total transfer function;

[0090] According to the total transfer function, obtain the hydraulic motor model of the cylindrical coordinate manipulator of the subsea drill rig.

[0091] The specific construction method is as follows:

[0092] (1) Modeling of the proportional amplifier and the proportional valve:

[0093] The proportional amplifier is used to activate the proportional valve. It is a voltage-current converter with a high output impedance and is regarded as a proportional amplification link to ensure that the electrical signal can be effectively converted and drive the proportional valve. Its transfer function is:

[0094]

[0095] where U(s) is the input voltage of the proportional amplifier, I(s) is the input current of the proportional amplifier, and K a is the proportional amplifier coefficient or gain.

[0096] The spool displacement of the solenoid valve is proportional to the input current of the proportional electromagnet, and the spool displacement determines the flow rate into the actuator. In engineering, the proportional valve is regarded as a second-order link, and its transfer function is as shown in Equation (2).

[0097]

[0098] where K sv is the displacement gain of the proportional valve, ω sv is the natural frequency of the proportional valve, and ζ sv is the damping ratio of the proportional valve.

[0099] (2) Modeling of the hydraulic valve-controlled motor system:

[0100] To deeply understand the dynamic characteristics of the hydraulic motor power mechanism and optimize the control strategy, the mathematical model of this embodiment is constructed and the following assumptions are made:

[0101] ① The pipeline is designed to be short and thick, so pressure loss and dynamic effects are ignored;

[0102] ② The internal and external leakage fluid flow states of the hydraulic motor are regarded as laminar flow, and the fluid density and temperature remain unchanged;

[0103] ③ The proportional valve is regarded as an ideal spool valve;

[0104] ④ The pressure of the main oil circuit of the hydraulic system remains unchanged, and the return oil pressure is assumed to be zero to prevent additional pressure loss;

[0105] ⑤ The bulk modulus of elasticity of the hydraulic oil remains unchanged under different system pressures;

[0106] ⑥ The elastic deformation between the motor and the load is ignored.

[0107] The linearized flow equation of the hydraulic motor electro-hydraulic proportional valve is shown in Equation (3):

[0108] q L =K q x v -K c p L (3)

[0109] q L is the load flow of the proportional valve, Kq is the flow gain of the proportional valve, x v is the spool displacement of the proportional valve, Kc is the flow-pressure coefficient of the proportional valve, and p L is the load pressure. After Laplace transform, we get:

[0110] Q L =K q X v -K c P L (4)

[0111] The flow continuity equation of the hydraulic motor is as shown in Equation (5):

[0112]

[0113] D mis the displacement of the hydraulic motor, θ m is the rotation angle of the hydraulic motor, C tm is the total leakage coefficient of the hydraulic motor, V t is the total volume of the hydraulic motor and its pipeline, β e is the effective volume elastic modulus of the working oil. After Laplace transform, Equation (6) can be obtained:

[0114]

[0115] The balance equation of the output torque and the load torque of the hydraulic motor is as shown in Equation (7):

[0116]

[0117] Among them, J t is the total moment of inertia of the hydraulic motor and the load, B m is the viscous damping coefficient, G is the load torque spring stiffness, T L is the external load torque. After Laplace transform, Equation (8) can be obtained:

[0118] D m P L =J t θ m s 2 +B m θ m +Gθ m +T L (8)

[0119] By combining Equations (4), (6), and (8), the expression of the total output angular displacement of the motor under the combined action of the spool displacement and the external load disturbance can be obtained as shown in Equation (9).

[0120]

[0121] It can be seen from Equation (9) that the output angular displacement of the hydraulic motor is related to physical quantities such as inertial load, oil compressibility, motor leakage, and elastic load. Simplifying Equation (9), when G = 0, and

[0122]

[0123] it can be obtained:

[0124]

[0125] Among them, ω h is the hydraulic natural frequency,

[0126] ξ h is the hydraulic damping coefficient,

[0127] is the speed amplification coefficient, dimensionless. From formula (11), the transfer function of the motor output angular displacement to the spool displacement can be obtained as follows:

[0128]

[0129] The transfer function of the motor output angular displacement to the external load torque is:

[0130]

[0131] The rotation angle θ m (s) and the rotational speed ω m are related by ω m = dθ m / dt. After Laplace transform, it can be obtained that θ m (s) = ω m / s. Formulas (12) and (13) can be transformed into:

[0132]

[0133] The sensor link can be regarded as a proportional link, and the sensor gain K f can be obtained as:

[0134]

[0135] From the conversion relationship between the joint space and the driving space, the mathematical model of the hydraulic motor angle position control system can be obtained, as shown in Figure 6 . Among them, U 1 and θ 1 are the system set value and the output value, and the system transfer function is:

[0136]

[0137] The parameters of the hydraulic motor system are shown in Table 1. Substituting the data in Table 1 into the structure diagram of the hydraulic motor system, we can obtain Figure 7 .

[0138] Table 1

[0139]

[0140] Since the operating environment of the manipulator is at the deep seabed and the main force during the rotation process is relatively large, the comprehensive effect of the torque during the rotation process of the manipulator needs to be considered, and its expression is shown in formula (19).

[0141]

[0142] In the formula, T q is the driving torque of the hydraulic motor, T f is the torque generated by the seawater resistance, and T mThe torque generated by each frictional force, J is the moment of inertia, and B is the viscous damping coefficient.

[0143] The hydrodynamic water resistance is as shown in Equation (20):

[0144]

[0145] In the formula, C f is the seawater damping coefficient, ρ h is the seawater density, A e is the water-facing area of the actuator, and v is the moving speed of the actuator.

[0146] The expression of the resistance torque exerted by water on the area is as shown in Equation (21):

[0147]

[0148] In the formula, (r 1 , r 2 ) is the acting area, r is the radius of the area, and h is the height of the acting area.

[0149] The expression of the combined torque of the frictional forces is as shown in Equation (22):

[0150]

[0151] In the formula, p max is the maximum peak pressure, and q is the displacement of the hydraulic motor.

[0152] Furthermore, using the manipulator fuzzy PID angle control method to control the current angle output value includes:

[0153] Obtaining the deviation and deviation rate between the current angle output value and the given angle;

[0154] Performing fuzzy processing on the deviation and deviation rate, and combining with the fuzzy rule base to obtain the correction coefficient;

[0155] Performing defuzzification processing on the correction coefficient, and combining with the initial control parameters to obtain the final control parameters;

[0156] Using the final control parameters to control the current angle output value.

[0157] Specifically, fuzzy control is a non-linear control technology with good robustness. The structure diagram of the fuzzy controller is as Figure 8 shown, and it mainly consists of fuzzification, fuzzy rule base, fuzzy inference, and defuzzification. Combining fuzzy control and traditional PID control can form fuzzy PID control. This control method can adaptively adjust the parameters of PID according to the customized fuzzy rules, enabling it to adapt to the changing control system. The schematic diagram of fuzzy PID is as Figure 9 shown.

[0158] The inputs of the fuzzy PID are the system deviation e and the change rate ec of the system deviation. Through fuzzyfication and a customized fuzzy rule base, the correction coefficients ΔK P 、ΔK I and ΔK D can be obtained. Then, through defuzzification, the increment values of the PID controller parameters can be obtained, and the parameters of the PID controller are adjusted in real time. The corrected PID parameters are shown in Equation (23).

[0159]

[0160] K P 、K I 、K D are the final control parameters of the PID controller respectively;

[0161] k p 、k i 、k d are the initial control parameters of the PID controller respectively;

[0162] ΔK P 、ΔK I and ΔK D are the parameter increments of the PID controller respectively;

[0163] In this system, the fuzzy PID angle controller of the manipulator is a two-input and three-output system. According to the actual design and operation of the system and the simulation experiment, the value ranges of the input and output variables are set as follows:

[0164] e ∈ [-350, 350], ec ∈ [-1000, 1000], ΔK P ∈ [-3, 10], ΔK I ∈ [-0.5, 0.5], ΔK D ∈ [-0.05, 0.05].

[0165] The value range of the domain of the fuzzy controller is divided into {NB, NM, NS, ZO, PS, PM, PB}, which represent negative large, negative medium, negative small, zero, positive small, positive medium, and positive large respectively. In addition, the membership function is selected as the triangular membership function, which has strong linear regulation ability. The membership functions of each domain are as Figures 10 - 14 shown.

[0166] Regarding the formulation of fuzzy rules, it is usually based on engineering experiments and empirical induction to formulate a suitable fuzzy rule base. The main principles are as follows:

[0167] The deviation e refers to the difference between the current angle and the set angle; the change rate of the deviation ec reflects the changing trend of the deviation over time, that is, the changing speed of the gap between the current angle and the set angle. Through this value, the change of the future deviation can be predicted. For example, when ec is large, it indicates that the system is approaching or moving away from the set point rapidly. When ec is small or close to zero, it indicates that the system may have approached the stable state.

[0168] When e is large, it is necessary to reduce the error, improve the rapid response of the system, and appropriately increase ΔK P and reduce ΔK I 。

[0169] When e and ec are medium, ΔK P is slightly reduced, ΔK I and ΔK D are medium.

[0170] When e is small, overshoot should be prevented and the system stability should be improved. Appropriately increase the value of ΔK P , ΔK D , when ec is small, ΔK D increases; when ec is large, ΔK D decreases.

[0171] The fuzzy rules of the fuzzy PID are shown in Table 2. From left to right in the table are the rules for ΔK P , ΔK I and ΔK D . The membership functions of two inputs and three outputs are as Figures 10 - 14 shown, and the input-output surface view is as Figure 15 shown.

[0172] Table 2

[0173]

[0174] The following elaborates on this embodiment in conjunction with the attached Figures 16 - 20 :

[0175] According to the mathematical model of the cylindrical coordinate manipulator hydraulic motor control system shown in the figure, in this embodiment, Matlab / Simulink software is used to build its model and simulate and verify the control strategy. In the control strategy part, traditional PID control and fuzzy PID control are respectively adopted, and the two control methods are compared. During the comparison, different working conditions are divided. The first working condition is a single-step angle, the second working condition is multiple consecutive steps of the angle, and in the third working condition, the change of the combined torque of the load torque and the interference torque is also added to simulate the changing interference environment on the seabed.

[0176] (1) In the first working condition, the simulation models for controlling the manipulator angle using traditional PID control and fuzzy PID control are as follows Figures 16 - 17 as shown. Initially, k p = 10, k i = 0.5, k d = 0.05. Set the angle to step from 0 degrees in the initial state to 40 degrees at 1 s. The control effects under the two control methods are as follows Figure 18 shown. It can be seen from the figure that when the manipulator angle has a small - range step, the response speed of fuzzy PID is faster and the adjustment time is shorter.

[0177] (2) In the second working condition, the angle is continuously changed to verify the performance of the two control methods. The initial state is 0 degrees. At 1 s, the angle steps to 40 degrees, at 3 s it steps to 340 degrees, and at 5 s it steps to 140 degrees again. The control effects under the two control methods are as follows Figure 19 shown. It can be seen from the figure that when the manipulator angle changes continuously, the control effect of fuzzy PID is better than that of traditional PID control in terms of rapidity and stability. Especially when the angle changes greatly, the overshoot of traditional PID control is large and the adjustment time is long. It can also be concluded from the results shown in the figure that when using fuzzy PID control, as the angle steps, the response speed can be adaptively adjusted according to the magnitude of the step difference. When the angle deviation changes greatly, the response speed increases; when the angle deviation is small, the response speed decreases slightly. In contrast, the adaptive adjustment ability of traditional PID control is poor.

[0178] (3) In the third working condition, in the second working condition with continuous angle change, a combined torque composed of load torque and disturbance torque that changes continuously is added. Set the initial torque to 0, at 1 s it steps to 50 N·m, at 3 s the torque steps to 250 N·m, and at 5 s it steps to 150 N·m again. The control effects of the two control methods under the third working condition are as follows Figure 20 shown. It can be concluded from the figure that under torque change and disturbance, fuzzy PID control not only has a certain advantage in response speed, but also when the torque steps greatly, that is, when there is a large disturbance, the stability of fuzzy PID control is better than that of traditional PID control, and there is a large overshoot in the angle under traditional PID control.

[0179] In summary, based on the comparison of the simulation results of the above three working conditions, it can be concluded that for the cylindrical - coordinate manipulator of the subsea drill operating in a relatively harsh environment, the adjustment time of fuzzy PID control is shorter, and it has better stability when the manipulator angle and torque change greatly. In addition, the response speed can be adaptively adjusted according to the magnitude of the angle change, that is, when the angle deviation is large, the speed is fast; when the angle deviation is small, the speed is slow.

[0180] In this embodiment, the cylindrical coordinate manipulator of a subsea drilling rig is taken as the research object. When controlling its angle, the traditional PID control has poor environmental adaptability and weak anti-interference ability, and it cannot respond quickly to adapt to the changing operation requirements, which affects the control effect. Based on the modeling of the manipulator's hydraulic system, fuzzy control is introduced to adjust the parameters of PID in real time according to the error of the angle feedback and its change rate. Finally, a simulation model is built in Matlab / Simulink and three working conditions are simulated to conduct a comparative analysis of fuzzy PID and traditional PID. The simulation results show that the proposed fuzzy PID angle control strategy for the manipulator has good dynamic performance and anti-interference ability, thus improving the overall control accuracy and making it more adaptable to the complex marine environment.

[0181] The above are only the preferred specific embodiments of the present application, but the protection scope of the present application is not limited thereto. Any changes or substitutions that can be easily thought of by those skilled in the art within the technical scope disclosed in the present application should be covered by the protection scope of the present application. Therefore, the protection scope of the present application should be subject to the protection scope of the claims.

Claims

1. A fuzzy PID angle control method for a cylindrical coordinate manipulator of a drilling rig, characterized in that: include: Construct a hydraulic model of the rotary mechanism of the cylindrical coordinate manipulator of the submarine drilling rig; According to the hydraulic model of the rotary mechanism of the cylindrical coordinate manipulator of the submarine drilling rig, a control model of the hydraulic motor of the cylindrical coordinate manipulator of the submarine drilling rig is constructed; Inputting a given input signal into the hydraulic motor control model of the cylindrical coordinate manipulator of the seabed drilling rig to obtain a current angle output value; The parameters of PID control are adaptively adjusted according to fuzzy rules so that the current angle output value can better track the given value, thus realizing the adjustment and control of the robot angle.

2. The fuzzy PID angle control method for a drilling rig cylindrical coordinate manipulator according to claim 1 is characterized in that: The hydraulic model of the rotary mechanism of the cylindrical coordinate manipulator of the seabed drilling rig comprises: an electric motor, a hydraulic pump, a pressure compensator, a proportional directional valve, a relief valve and a hydraulic motor.

3. The fuzzy PID angle control method for a drilling rig cylindrical coordinate manipulator according to claim 2 is characterized in that: The hydraulic motor model of the cylindrical coordinate manipulator of the seabed drilling rig comprises: a controller module, a proportional amplification module, an electro-hydraulic proportional valve module, a hydraulic motor module, an execution module and a detection feedback module.

4. The fuzzy PID angle control method for a drilling rig cylindrical coordinate manipulator according to claim 3 is characterized in that: Constructing the hydraulic motor model of the cylindrical coordinate manipulator of the submarine drilling rig includes: Obtaining a transfer function of the proportional amplification module; Obtaining a transfer function of the electro-hydraulic proportional valve module; Acquire the valve core displacement of the electro-hydraulic proportional valve module, and acquire the angular displacement of the hydraulic motor in combination with external load interference; According to the angular displacement, a transfer function of the angular displacement to the valve core displacement and a transfer function of the angular displacement to the external load torque are obtained; Obtaining a total transfer function according to the transfer function of the proportional amplification module, the transfer function of the electro-hydraulic proportional valve module, the transfer function of the angular displacement to the valve core displacement, and the transfer function of the angular displacement to the external load torque; According to the total transfer function, a control model of the hydraulic motor of the cylindrical coordinate manipulator of the seabed drilling rig is obtained.

5. A drilling rig cylindrical coordinate manipulator fuzzy PID angle control method according to claim 4, characterized in that: The method for obtaining the transfer function of the proportional amplification module is: Among them, U(s) is the proportional amplifier input voltage, I(s) is the proportional amplifier input current, K a is the proportional amplifier coefficient; The method for obtaining the transfer function of the electro-hydraulic proportional valve module is: Among them, X v is the displacement of the proportional valve core, I is the input current of the electromagnet, s is the Laplace operator, K sv is the displacement gain of the proportional valve, ω sv Proportional valve natural frequency, ζ sv Proportional valve damping ratio; The method to obtain the angular displacement of the hydraulic motor is: Among them, D m is the displacement of the hydraulic motor, θ m is the hydraulic motor rotation angle, Kq is the proportional valve flow gain, β e is the effective bulk elastic modulus of the working oil, T L is the external load moment, V t is the total volume of the hydraulic motor and its pipeline, J t is the total moment of inertia of the hydraulic motor and the load, B m is the viscous damping coefficient, ω h is the hydraulic natural frequency, ξ h is the hydraulic damping coefficient, K ce is the total flow of the hydraulic motor; The method to obtain the transfer function of angular displacement to valve core displacement is: Among them, θ m (s) is the angular displacement, X v (s) is the valve core displacement; The method to obtain the transfer function of angular displacement to external load torque is: Among them, T L (s) is the external load moment, θ m (s) is the angular displacement; The method for obtaining the total transfer function is: Among them, G(s) is the system function, U f (s) is the feedback signal, U e (s) is the error signal.

6. The fuzzy PID angle control method for a drilling rig cylindrical coordinate manipulator according to claim 1 is characterized in that: Adaptively adjusting the parameters of PID according to fuzzy rules to reduce the difference between the current angle output value and the set angle, and realizing the adjustment control of the robot angle includes: Obtaining the deviation and deviation rate between the current angle output value and a given angle; Performing fuzzy processing on the deviation and the deviation rate, and obtaining a correction coefficient in combination with a fuzzy rule base; Defuzzifying the correction coefficient and obtaining the final control parameter by combining the initial control parameter; The current angle output value is controlled using the final control parameter.

7. The fuzzy PID angle control method for a cylindrical coordinate manipulator of a drilling rig according to claim 6 is characterized in that: The method of controlling the parameters is: Among them, K P , K I , K D are the final control parameters of the PID controller, k p , k i , k d are the initial control parameters of the PID controller, ΔK P , ΔK I and ΔK D They are the parameter increments output by the fuzzy controller respectively.

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