Force-position control system and working method for connecting a sea walkway to a floating platform

Abstract

The application discloses a force-position control system and a working method for connecting a marine corridor bridge with a floating platform, wherein a main active motion compensation control unit in the force-position control system can compensate for six-degree-of-freedom motion of a service ship and the marine floating platform, control a corridor bridge tip point (a front end center of a bridge body of the corridor bridge) to follow motion of a marine floating platform connecting point (a position of the marine floating platform suitable for connecting the corridor bridge tip point), and make the corridor bridge tip point follow the motion of the marine floating platform connecting point; after the corridor bridge tip point is connected with the connecting point, a force control unit in the force-position control system makes the corridor bridge tip point and the connecting point keep a constant expected three-dimensional contact force, so that the three-dimensional contact force between the corridor bridge tip point and the connecting point is prevented from being too large, and damage to the corridor bridge and the marine floating platform is avoided. The application can realize fixed-free connection of the corridor bridge tip point and the connecting point, facilitates emergency evacuation of the corridor bridge, and greatly improves safety of a transfer operation.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of marine and ocean engineering, in particular to a force and position control system for connecting a sea bridge to a floating platform and a working method thereof, which enables the sea bridge to be stably connected to the floating platform and ensures the safe transfer of personnel. BACKGROUND

[0002] With the development of marine economy, offshore wind power has developed rapidly. Both offshore fixed wind turbine platforms and deep-sea floating wind turbine platforms need regular maintenance and care. The most economical, safe and convenient way is to transfer maintenance personnel to offshore wind turbine platforms by maintenance ships. The installation of a sea bridge on the maintenance ship can establish a transfer channel for personnel and materials between the maintenance ship and the offshore wind turbine platform. The present application designs a force and position control system for connecting a sea bridge to a floating platform, which enables the sea bridge to be stably connected to the floating platform and ensures the safe transfer of personnel between the maintenance ship and the offshore floating platform.

[0003] Chinese patent CN110761172A discloses a telescopic trestle system and a control method thereof. The trestle is installed on a support platform or a support ship and includes a rotating mechanism, an amplitude changing mechanism, a telescopic mechanism and a motion compensation control system. The front end of the moving section of the trestle is provided with a landing device and an inclined ladder. The motion compensation control system can compensate for the six-degree-of-freedom motion of the support platform or the support ship and increase the displacement in the telescopic direction of the trestle to apply appropriate contact force to the offshore fixed platform at the end of the trestle. Since the trestle is mainly used for personnel transfer between the support ship and the offshore fixed platform, it does not have the function of compensating for the motion of the offshore platform and cannot ensure the safe transfer of personnel between the maintenance ship and the offshore floating platform.

[0004] Chinese patent CN13104153A discloses a wave compensation control system for offshore transfer trestle and a working method thereof. The wave compensation control system includes a hydraulic actuator, a measurement system, an electro-hydraulic servo valve, a wave compensation control unit, a control box, a PLC and a main control computer. After the front end of the trestle body is connected to the transfer point on the target ship, the rotating, pitching and telescopic mechanisms compensate for the disturbance of the motion of the two ships to the trestle in a passive manner. Therefore, the trestle does not have the function of controlling the contact force between the front end of the trestle body and the transfer point on the target ship. When the disturbance of the motion of the two ships to the trestle caused by changes in sea conditions is too large, it will cause the contact force between the front end of the trestle body and the transfer point on the target ship to be too large, which will cause damage to the trestle and the target ship. SUMMARY

[0005] To solve the above problems existing in the prior art, the present application provides a force and position control system and a working method for connecting a marine promenade bridge and a floating platform, wherein the active motion compensation control unit in the force and position control system can compensate for the six-degree-of-freedom motion of the service ship and the offshore floating platform, control the motion of the promenade bridge tip point (the front end center of the promenade bridge body) to follow the motion of the offshore floating platform connection point (a position of the offshore floating platform suitable for connecting the promenade bridge tip point), and make the promenade bridge tip point follow the motion of the offshore floating platform connection point; after the promenade bridge tip point is connected with the connection point, the force control unit in the force and position control system keeps the constant expected three-dimensional contact force between the promenade bridge tip point and the connection point, so as to avoid the three-dimensional contact force between the promenade bridge tip point and the connection point being too large and causing damage to the promenade bridge and the offshore floating platform.

[0006] To achieve the above-mentioned purpose, the technical scheme of the present application is as follows:

[0007] The force and position control system for connecting the marine promenade bridge and the offshore floating platform comprises the marine promenade bridge and the force and position control system.

[0008] The marine promenade bridge comprises a bridge body, a base, a transfer deck and a hydraulic actuator; the bridge body is composed of a bridge body fixed part and a bridge body telescopic part; the base is fixedly installed on the deck of the service ship; the hydraulic actuator comprises a first hydraulic motor, a hydraulic cylinder and a second hydraulic motor; the first hydraulic motor is used to drive the transfer deck and the bridge body to produce rotary motion; the hydraulic cylinder is used to drive the bridge body to produce pitching motion around the shaft connecting the transfer deck and the bridge body fixed part; and the second hydraulic motor is used to drive the bridge body telescopic part to move along the bridge body fixed part.

[0009] The force and position control system comprises a motion reference unit (MRU), a camera, a tip point follow-up expected position calculation unit, an active motion compensation control unit and a force control unit; the MRU is installed on the service ship and is used to measure the six-degree-of-freedom motion state of the service ship, i.e., roll x, pitch y, heave z, sway surge θ and yaw ψ; the camera is installed at the near tip point of the lower surface of the bridge body and is used to measure the relative position between the tip point and the connection point in the OX coordinate

[0010] In order to facilitate the description of the tip point position, an inertial coordinate system O XYZ is defined according to the right-hand rule, the coordinate origin O is any point on the earth's surface, the OX axis points to the north, the OY axis points to the east, and the OZ axis points to the center of the earth; the camera is installed at the near tip point of the lower surface of the bridge body and is used to measure the relative position between the tip point and the connection point in the OX coordinate in the OY coordinate and in the OZ coordinate denote the relative position vector of the tip point and the connection point;

[0011] ​The tip point follow-up desired position calculation unit comprises a kinematics forward solution module. The bridge operator sets the tip point desired position as a suitable position above the lap joint point according to the position of the lap joint point and actual lap joint operation requirements, and the desired position of the tip point in the OX coordinate, OY coordinate and OZ coordinate in the inertial coordinate system O XYZ is respectively and Record The tip point desired position vector is represented; the kinematics forward solution module calculates the position change amount of the tip point in the OX coordinate caused by the six-degree-of-freedom motion of the maintenance ship according to the six-degree-of-freedom motion state of the maintenance ship measured by the MRU The position change amount in the OY coordinate is and the position change amount in the OZ coordinate is Record The position change vector of the tip point caused by the six-degree-of-freedom motion of the maintenance ship is represented; the tip point follow-up desired position calculation unit receives the relative position vector ΔX between the tip point and the lap joint point from the camera s , and according to the tip point desired position vector X set by the operator r and the position change vector ΔX of the tip point caused by the six-degree-of-freedom motion of the maintenance ship c , calculates the tip point follow-up desired position vector X that keeps the relative position between the tip point and the lap joint point unchanged d ;

[0012] The active motion compensation control unit comprises a sensor unit, a kinematics inverse solution module and a motion compensation controller.

[0013] The sensor unit comprises a first encoder for measuring the actual rotation angle h1 of the first hydraulic motor, a displacement sensor for measuring the actual extension and retraction displacement h2 of the hydraulic cylinder and a second encoder for measuring the actual rotation angle h3 of the second hydraulic motor; record h = [h1, h2, h3] T The actual position vector of the hydraulic actuator is represented;

[0014] The kinematics inverse solution module receives the tip point follow-up desired position vector X from the tip point follow-up desired position calculation unit d and the tip point follow-up desired position correction vector ΔX from the force control unit, calculates the corrected follow-up desired position vector X d ′ = X d - ΔX, calculates the desired rotation angle q of the transfer deck and the bridge body, the desired pitch angle q of the bridge body and the desired extension and retraction displacement q of the bridge body according to the kinematics equation of the bridge and X d ′, record d1 q = [q d2 q d3 , q d = [q d1q d2 q d3 ] T Furthermore, based on the reduction ratio of the first hydraulic motor reducer, the desired rotation angle q for the transfer deck and bridge body to track is calculated. d1 The first hydraulic motor has a desired rotation angle h d1 Based on the geometric relationship between the hydraulic cylinder extension / retraction and the bridge's pitch angle, the desired pitch angle q for the bridge to track its trajectory is calculated. d2 The expected extension / retraction h of the hydraulic cylinder d2 Based on the reduction ratio of the second hydraulic motor reducer, the desired extension displacement q that makes the bridge body track its extension and contraction is calculated. d3 The desired rotation angle h of the second hydraulic motor d3 , remember h d =[h d1 h d2 h d3 ] T This represents the desired position vector of the hydraulic actuator;

[0015] The motion compensation controller receives the desired rotation angle h from the first hydraulic motor of the inverse kinematics module. d1 The expected extension / retraction amount h of the hydraulic cylinder d2 The desired rotation angle h of the second hydraulic motor d3 That is, the actual position vector h of the hydraulic actuator is obtained, and the actual rotation angle h1 of the first hydraulic motor, the actual extension and retraction displacement h2 of the hydraulic cylinder, and the actual rotation angle h3 of the second hydraulic motor are received from the sensor unit, thus obtaining the desired position vector h of the hydraulic actuator. d ; Calculate the position deviation vector Δh = h of the hydraulic actuator. d Based on this, the control signals u1 for the first hydraulic motor to track its desired rotation angle, u2 for the hydraulic cylinder to track its desired extension / retraction displacement, and u3 for the second hydraulic motor to track its desired rotation angle are calculated respectively. Let u = [u1, u2, u3]. T To ensure the desired position vector X after tracking correction of the bridge tip is maintained. d ′=X d -ΔX;

[0016] The force control unit includes a three-dimensional force sensor and an impedance controller;

[0017] According to the right-hand rule, the coordinate system T_XYZ of the apex point is defined, with its origin T located at the apex point, the TX axis pointing to the end of the bridge body along the direction of bridge body extension and contraction, the TY axis perpendicular to the TX axis pointing to the right side of the bridge body, and the TZ axis perpendicular to the TXY plane and upward.

[0018] The three-dimensional force sensor is installed at the tip of the walkway bridge to measure the actual three-dimensional contact force between the tip and the overlap point, including the contact force at the tip along the TX axis. Contact force along the TY axis and contact force along the TZ axis Denote the actual three-dimensional contact force vector

[0019] The impedance controller uses spring, mass, and damping characteristics to simulate the dynamics of the contact force between the tip and the overlap, thus correcting the vector for the desired position of the tip. The three-dimensional contact force deviation vector between the tip and the overlap point The relationship between them exhibits characteristics of a spring, mass, and damping; therefore, the differential equations for each degree of freedom of the impedance controller are:

[0020]

[0021] In the formula, m i Let be the virtual masses of the three degrees of freedom of motion of the tip of the covered bridge along the TX, TY, and TZ axes, respectively. The virtual mass matrix representing the tip; b i Let be the virtual damping of the three degrees of freedom of motion of the tip of the covered bridge along the TX, TY, and TZ axes, respectively. The virtual damping matrix representing the tip; k i Let be the stiffness damping of the tip along the TX, TY, and TZ axes, respectively. This represents the virtual stiffness matrix at the tip. Let be the correction amounts for the desired position of the tip along the TX, TY, and TZ axes, respectively. Δf represents the desired position correction vector of the apex in the apex coordinate system T_XYZ; i =f di -f i These represent the force deviations between the tip and the overlap point along the TX, TY, and TZ axes, respectively. di Let be the contact forces between the tip and the lap joint along the TX, TY, and TZ axes, respectively, when the tip is touching the lap joint of the floating platform and the maintenance vessel and platform are stationary; and let be the desired three-dimensional contact force vector between the tip and the lap joint. Then there is This represents the three-dimensional contact force deviation vector between the tip and the overlap point;

[0022] The impedance controller obtains the desired position correction vector ΔX of the tip in the tip coordinate system based on the three-dimensional contact force deviation vector ΔF and equation (1). t Then transform it into the desired position correction vector in the inertial coordinate system O_XYZ. wherein, is a follow-up desired position correction amount in the OX coordinate, is a follow-up desired position correction amount in the OY coordinate, is a follow-up desired position correction amount in the OZ coordinate.

[0023] The working method of the force-position control system for connecting a marine corridor bridge with a marine floating platform comprises the following steps:

[0024] A. After the operation and maintenance ship approaches the marine floating platform, the operator controls the hydraulic actuator of the corridor bridge according to the position of the connecting point, so that the tip point of the corridor bridge reaches a suitable position above the connecting point of the marine floating platform.

[0025] B. The operator starts the force-position control system of the corridor bridge, and the motion compensation control unit of the force-position control system controls the tip point of the corridor bridge to track the follow-up desired position, so that the tip point of the corridor bridge follows the connecting point to ensure that the relative position of the tip point and the connecting point remains unchanged.

[0026] C. After the tip point of the corridor bridge is connected to the connecting point of the marine floating platform, the motion compensation control unit of the force-position control system controls the tip point of the corridor bridge to follow the connecting point. At the same time, the force control unit of the force-position control system obtains the follow-up desired position correction amount for eliminating the three-dimensional contact force deviation between the tip point of the corridor bridge and the connecting point through the impedance controller, which is used to correct the follow-up desired position received by the motion compensation control unit. The motion compensation control unit controls the tip point of the corridor bridge to track the corrected follow-up desired position, so that the tip point of the corridor bridge and the connecting point maintain a constant desired three-dimensional contact force.

[0027] Compared with the prior art, the present application has the following beneficial effects:

[0028] 1. The present application proposes a force-position control system for connecting a marine corridor bridge with a marine floating platform, which controls the position of the tip point of the corridor bridge and the three-dimensional contact force between the tip point of the corridor bridge and the connecting point, to ensure stable contact between the tip point of the corridor bridge and the connecting point, avoid damage to the corridor bridge and the platform caused by excessive contact force between the corridor bridge and the platform due to changes in sea conditions, and realize fixed connection between the tip point of the corridor bridge and the connecting point, which facilitates emergency evacuation of the corridor bridge and greatly improves the safety of the transfer operation.

[0029] 2. The present application can be connected to marine structures such as offshore fixed platforms, offshore floating platforms and ships, and does not require the connected object to install any device for corridor bridge connection. As long as there is a suitable area for corridor bridge connection, safe and stable connection can be achieved, i.e. the configuration requirements for the connected object are low and the application scope is wide. BRIEF DESCRIPTION OF DRAWINGS

[0030] Figure 1It is a schematic diagram of the mechanical structure of the gallery bridge.

[0031] Figure 2 It is a local enlarged view of the end of the gallery bridge body.

[0032] Figure 3 It is a schematic diagram of the virtual spring mass damping characteristics between the tip point and the platform overlap point of the gallery bridge.

[0033] Figure 4 It is a schematic diagram of the force-position control system of the gallery bridge.

[0034] In the figure: 1, base, 2, first hydraulic motor, 3, transfer deck, 4, hydraulic cylinder, 5, second hydraulic motor, 6, bridge body fixed part, 7, bridge body telescopic part, 8, three-dimensional force sensor, 9, camera, 10, floating platform. DETAILED DESCRIPTION

[0035] The application will be further described below in conjunction with the drawings. As shown in the drawings, 1, a force-position control system for the overlap of a gallery bridge and a floating platform at sea, comprising a gallery bridge at sea and a force-position control system; Figures 1-4

[0036] The gallery bridge at sea comprises a bridge body, a base 1, a transfer deck 3 and a hydraulic actuator; the bridge body is composed of a bridge body fixed part 6 and a bridge body telescopic part 7; the base 1 is fixedly installed on the deck of a service ship; the hydraulic actuator comprises a first hydraulic motor 2, a hydraulic cylinder 4 and a second hydraulic motor 5; the first hydraulic motor 2 is used to drive the transfer deck 3 and the bridge body to produce rotary motion; the hydraulic cylinder 4 is used to drive the bridge body to produce pitching motion around the shaft connecting the transfer deck 3 and the bridge body fixed part 6; the second hydraulic motor 5 is used to drive the bridge body telescopic part 7 to move along the bridge body fixed part 6;

[0037] The force-position control system comprises a motion reference unit (MRU), a camera 9, a tip point follow-up desired position calculation unit, an active motion compensation control unit and a force control unit; the MRU is installed on the service ship and is used to measure the six degrees of freedom motion states of the service ship, i.e. roll x, pitch y, heave z, sway , surge θ and yaw ψ;

[0038] In order to facilitate the description of the tip point position, an inertial coordinate system O XYZ is defined according to the right-hand rule, the coordinate origin O is any point on the earth's surface, the OX axis points to the north, the OY axis points to the east, and the OZ axis points to the center of the earth; the camera 9 is installed at the near tip point of the lower surface of the bridge body and is used to measure the relative position of the tip point and the overlap point in the OX coordinate , the relative position in the OY coordinate , and the relative position in the OZ coordinate​ Let denote the relative position vector of the tip point and the lap point;

[0039] The tip point follow-up desired position calculation unit comprises a kinematics forward solution module; the operator sets the tip point desired position as a suitable position above the lap point according to the position of the lap point and the actual lap joint operation demand, and the desired position of the tip point in the OX coordinate, the OY coordinate and the OZ coordinate in the inertial coordinate system O_XYZ is respectively and Let denote the tip point desired position vector; the kinematics forward solution module calculates the position change amount of the tip point in the OX coordinate caused by the six-degree-of-freedom motion of the operation ship according to the six-degree-of-freedom motion state of the operation ship measured by the MRU the position change amount in the OY coordinate and the position change amount in the OZ coordinate Let denote the position change vector of the tip point caused by the six-degree-of-freedom motion of the operation ship; the tip point follow-up desired position calculation unit receives the relative position vector ΔX between the tip point and the lap point from the camera 9 s , and calculates the tip point follow-up desired position vector X r that keeps the relative position of the tip point and the lap point unchanged according to the tip point desired position vector X c set by the operator and the position change vector ΔX d of the tip point caused by the six-degree-of-freedom motion of the operation ship;

[0040] The active motion compensation control unit comprises a sensor unit, a kinematics inverse solution module and a motion compensation controller;

[0041] The sensor unit comprises a first encoder for measuring the actual rotation angle h1 of the first hydraulic motor 2, a displacement sensor for measuring the actual extension displacement h2 of the hydraulic cylinder 4 and a second encoder for measuring the actual rotation angle h3 of the second hydraulic motor 5; let h = [h1, h2, h3] T denote the actual position vector of the hydraulic actuator;

[0042] The kinematics inverse solution module receives the tip point follow-up desired position vector X d from the tip point follow-up desired position calculation unit and the tip point follow-up desired position correction vector ΔX from the force control unit, and calculates the corrected follow-up desired position vector X d ′ = X d - ΔX, calculates the desired rotation angle q d of the transfer deck 3 and the bridge body according to the kinematics equation of the bridge and X d1, the desired pitch angle q of the bridge d2 and the desired telescopic displacement q of the bridge d3 , let q d =[q d1 , q d2 , q d3 ] T ; further, according to the reduction ratio of the first hydraulic motor 2 reducer, the desired rotation angle h d1 of the first hydraulic motor 2 is calculated to make the transfer deck 3 and the bridge track their desired rotation angle q d1 , according to the geometric relationship between the telescopic displacement of the hydraulic cylinder 4 and the pitch angle of the bridge, the desired telescopic displacement h d2 of the hydraulic cylinder 4 is calculated to make the bridge track its desired pitch angle q d2 , according to the reduction ratio of the second hydraulic motor 5 reducer, the desired rotation angle h d3 of the second hydraulic motor 5 is calculated to make the bridge track its desired telescopic displacement q d3 , let h d =[h d1 , h d2 , h d3 ] T represent the desired position vector of the hydraulic actuator;

[0043] The motion compensation controller receives the desired rotation angle h d1 of the first hydraulic motor 2, the desired telescopic displacement h d2 of the hydraulic cylinder 4, and the desired rotation angle h d3 of the second hydraulic motor 5 from the inverse kinematics module, i.e. obtains the actual position vector h of the hydraulic actuator, receives the actual rotation angle h1 of the first hydraulic motor 2, the actual telescopic displacement h2 of the hydraulic cylinder 4, and the actual rotation angle h3 of the second hydraulic motor 5 from the sensor unit, i.e. obtains the desired position vector h d of the hydraulic actuator; calculates the position deviation vector Δh = h d -h of the hydraulic actuator, and according to which, the control signal u1 to make the first hydraulic motor 2 track its desired rotation angle, the control signal u2 to make the hydraulic cylinder 4 track its desired telescopic displacement, and the control signal u3 to make the second hydraulic motor 5 track its desired rotation angle are calculated respectively, let u = [u1, u2, u3] T to ensure that the gallery bridge tip point tracks the corrected follow-up desired position vector X d ′ = X d -ΔX;

[0044] The force control unit includes a three-dimensional force sensor 8 and an impedance controller;

[0045] A tip point coordinate system T_XYZ is defined according to the right-hand rule, with its origin T at the tip point, TX axis pointing to the end of the bridge along the bridge extension direction, TY axis perpendicular to TX axis pointing to the right side of the bridge, and TZ axis perpendicular to TXY plane pointing upward;

[0046] The three-dimensional force sensor 8 is installed at the tip point of the gallery bridge, for measuring the actual three-dimensional contact force between the tip point and the landing point, including the contact force along TX axis direction at the tip point the contact force along TY axis direction and the contact force along TZ axis direction Let the actual three-dimensional contact force vector be

[0047] The impedance controller simulates the tip point and landing point contact force dynamics with spring, mass and damping characteristics, i.e. the relationship between the desired position correction vector and the three-dimensional contact force deviation vector between the tip point and the landing point The impedance controller has the spring, mass and damping characteristics, so the differential equation of each degree of freedom of the impedance controller is:

[0048]

[0049] In the formula, m i are the virtual masses of the three motion degrees of freedom of the gallery bridge tip point along TX, TY and TZ axes, respectively, let denote the virtual mass matrix of the tip point; b i are the virtual dampings of the three motion degrees of freedom of the gallery bridge tip point along TX, TY and TZ axes, respectively, let denote the virtual damping matrix of the tip point; k i are the stiffness dampings of the three degrees of freedom of the tip point along TX, TY and TZ axes, respectively, let denote the virtual stiffness matrix at the tip point; are the servo desired position correction amounts of the tip point along TX, TT and TZ axes directions, respectively, let denote the servo desired position correction vector of the tip point in the tip point coordinate system T_XYZ; Δf i = f di -f i are the force deviations between the tip point and the landing point along TX, TY and TZ axes directions, respectively, f di are the contact forces between the tip point and the landing point along TX, TT and TZ axes directions when the tip point is landed on the landing point of the offshore floating platform 10, and the service ship and the platform are static; let the desired three-dimensional contact force vector between the tip point and the landing point be then denote the three-dimensional contact force deviation vector between the tip point and the landing point;

[0050] The impedance controller obtains the servo desired position correction vector of the tip point in the tip point coordinate system according to the three-dimensional contact force deviation vector and formula 1 t And then it is transformed into the desired position correction vector in the inertial coordinate system O_XYZ Wherein, is the servo desired position correction in the OX coordinate, is the servo desired position correction in the OY coordinate, is the servo desired position correction in the OZ coordinate.

[0051] The working method of the force-position control system for connecting the offshore corridor bridge with the offshore floating platform comprises the following steps:

[0052] A. After the operation and maintenance ship approaches the offshore floating platform 10, the operator controls the hydraulic actuator of the corridor bridge according to the position of the connecting point, so that the tip point of the corridor bridge reaches a suitable position above the connecting point of the offshore floating platform 10;

[0053] B. The operator starts the force-position control system of the corridor bridge, and the motion compensation control unit of the force-position control system controls the tip point of the corridor bridge to track the servo desired position, so that the tip point of the corridor bridge follows the motion of the connecting point and ensures that the relative position of the tip point and the connecting point is unchanged;

[0054] C. After the tip point of the corridor bridge is connected to the connecting point of the offshore floating platform 10, the motion compensation control unit of the force-position control system controls the tip point of the corridor bridge to follow the motion of the connecting point; at the same time, the force control unit of the force-position control system obtains the servo desired position correction for eliminating the three-dimensional contact force deviation between the tip point of the corridor bridge and the connecting point through the impedance controller, and the servo desired position correction is used to correct the servo desired position received by the motion compensation control unit, and then the motion compensation control unit controls the tip point of the corridor bridge to track the corrected servo desired position, so that the tip point of the corridor bridge and the connecting point maintain a constant desired three-dimensional contact force.

[0055] The present application is not limited to the embodiments, and any equivalent concept or change within the technical scope disclosed in the present application is included in the protection scope of the present application.

Claims

1. A force-position control system for the docking of a sea walkway to a floating offshore platform, characterized in that: The offshore corridor bridge and the force-position control system are included. The offshore corridor bridge includes a bridge body, a base (1), a transfer deck (3) and a hydraulic actuator; the bridge body is composed of a bridge body fixed part (6) and a bridge body telescopic part (7); the base (1) is fixedly installed on the deck of a service ship; the hydraulic actuator includes a first hydraulic motor (2), a hydraulic cylinder (4) and a second hydraulic motor (5); the first hydraulic motor (2) is used to drive the transfer deck (3) and the bridge body to generate rotary motion; the hydraulic cylinder (4) is used to drive the bridge body to generate pitching motion around the shaft connecting the transfer deck (3) and the bridge body fixed part (6); and the second hydraulic motor (5) is used to drive the bridge body telescopic part (7) to move along the bridge body fixed part (6). The force-position control system includes a motion reference unit (MRU), a camera (9), a tip-point follow-up desired position calculation unit, an active motion compensation control unit, and a force control unit; the MRU is installed on the maintenance vessel and is used to measure the roll of the maintenance vessel. , swaying Rise and fall , sweeping , unrestrained and bow rocking The motion states have six degrees of freedom. ; To facilitate illustrating the location of the apex, an inertial coordinate system is defined according to the right-hand rule. O_XYZ Its coordinate origin For any point on the Earth's surface, The axis points due north. The axis points due east. The axis points towards the Earth's center; the camera (9) is mounted near the tip of the lower surface of the bridge body to measure the distance between the tip and the overlap point. Relative position on coordinates ,exist Relative position on coordinates and in Relative position on coordinates ,remember This represents the relative position vector between the tip and the overlap point; The desired position calculation unit for the tip point includes a forward kinematics module; the bridge operator sets the desired position of the tip point to a suitable position above the overlap point based on the location of the overlap point and the actual overlap operation requirements, in the inertial coordinate system. O_XYZ Down coordinate, coordinates and The desired positions on the coordinates are respectively , and ,remember This represents the desired position vector of the tip; the forward kinematics module calculates the position of the tip caused by the six-degree-of-freedom motion of the maintenance vessel, based on the six-degree-of-freedom motion state of the maintenance vessel measured by the MRU. Change in position on coordinates ,exist Change in position on coordinates and in Change in position on coordinates ,remember This represents the position change vector of the tip point caused by the six-degree-of-freedom motion of the maintenance vessel; the tip point follow-up expected position calculation unit receives the relative position vector between the tip point and the overlap point from the camera (9). Then, based on the desired position vector of the tip set by the operator... and the vector of tip position change caused by the six-degree-of-freedom motion of the maintenance vessel Calculate the desired position vector of the tip while keeping the relative positions of the tip and the overlap point unchanged. ; The active motion compensation control unit includes a sensor unit, a kinematic inverse solution module and a motion compensation controller. The sensor unit comprises a first encoder for measuring the actual rotation angle of the first hydraulic motor (2), a displacement sensor for measuring the actual extension displacement of the hydraulic cylinder (4), and a second encoder for measuring the actual rotation angle of the second hydraulic motor (5); and represents the actual position vector of the hydraulic actuator. ​​​ The inverse kinematics module receives the desired position vector of the tip from the desired position calculation unit. and the tip-following desired position correction vector from the force control unit The corrected desired position vector after adjusting for maintaining a constant desired three-dimensional contact force is calculated. According to the kinematic equations of the covered bridge and The expected rotation angles of the transfer deck (3) and the bridge body were calculated. Desired pitch angle of the bridge and the expected expansion and contraction displacement of the bridge body ,remember Furthermore, based on the reduction ratio of the first hydraulic motor (2) reducer, the angle at which the transfer deck (3) and the bridge body track their desired rotation angle is calculated. The first hydraulic motor (2) has the desired rotation angle. Based on the geometric relationship between the extension and retraction of the hydraulic cylinder (4) and the pitch angle of the bridge, the method to make the bridge track its desired pitch angle is calculated. The expected extension / retraction of the hydraulic cylinder (4) Based on the reduction ratio of the second hydraulic motor (5) reducer, the required displacement for the bridge body to track its desired extension and contraction displacement is calculated. The desired rotation angle of the second hydraulic motor (5) ,remember This represents the desired position vector of the hydraulic actuator; The motion compensation controller receives the desired rotation angle of the first hydraulic motor (2) , the desired extension amount of the hydraulic cylinder (4) , the desired rotation angle of the second hydraulic motor (5) , and obtains the actual position vector of the hydraulic actuator , receives the actual rotation angle of the first hydraulic motor (2) , the actual extension displacement of the hydraulic cylinder (4) , and the actual rotation angle of the second hydraulic motor (5) , and obtains the desired position vector of the hydraulic actuator ; A position deviation vector of the hydraulic actuator is calculated , from which a control signal is calculated respectively so that the first hydraulic motor (2) tracks its desired rotation angle , a control signal of the hydraulic cylinder (4) tracks its desired extension displacement , a control signal of the second hydraulic motor (5) tracks its desired rotation angle , a record , to ensure that the gallery bridge tip point tracks the corrected follow-up desired position vector ; The force control unit includes a three-dimensional force sensor (8) and an impedance controller. Define the coordinate system of the apex point according to the right-hand rule. T_XYZ Its origin T Located at the apex, The shaft points towards the end of the bridge structure along the direction of bridge expansion and contraction. Axis perpendicular The axis points to the right side of the bridge body. The axis is perpendicular to the TXY plane and points upwards; The three-dimensional force sensor (8) is installed at the tip point of the gallery bridge for measuring the actual three-dimensional contact force between the tip point and the lap point, including the contact force along the axial direction at the tip point , the contact force along the axial direction , and the contact force along the axial direction , and the actual three-dimensional contact force vector ; The impedance controller presents spring, mass and damping characteristics to simulate the tip point and lap point contact force dynamics, even if the desired position correction vector and the three-dimensional contact force deviation vector between the tip point and the lap point of the tip point are modified Thus, the differential equations for each degree of freedom of the impedance controller are: （1） In the formula, The tip of the covered bridge along , and The virtual mass of the three degrees of freedom of the axis of motion, denoted as The virtual mass matrix representing the tip; The tip of the covered bridge along , and The virtual damping of the three degrees of freedom of the axis is denoted as... The virtual damping matrix represents the tip. They are the tips along the edges , and The stiffness and damping of the three degrees of freedom of the axis, denoted as This represents the virtual stiffness matrix at the tip. They are the tips along the edges , and The desired position correction in the axial direction is denoted as... Indicates the position of the apex in the apex coordinate system. T_XYZ The expected position correction vector under the following conditions; The points between the tip and the overlap are respectively along , and Force deviation in the axial direction, The tip of the vessel is attached to the joint point of the floating platform (10) at the sea surface, and the maintenance vessel is stationary with the platform. , and The contact force between the apex and the overlap point along the axial direction; denote the desired three-dimensional contact force vector between the apex and the overlap point. Then there is This represents the three-dimensional contact force deviation vector between the tip and the overlap point; The impedance controller is based on the three-dimensional contact force deviation vector. And with equation (1), the desired position correction vector of the tip in the tip coordinate system is obtained. Then transform it into an inertial coordinate system. O_XYZ The expected position correction vector below ,in, In order to be in The expected position correction amount on the coordinate system. In order to be in The expected position correction amount on the coordinate system. In order to be in The expected position correction amount on the coordinate system.

2. The method of claim 1, wherein the force-position control system is used for the offshore jetty bridge and offshore floating platform connection, and the method comprises the following steps: The method includes the following steps: A. After the service ship approaches the offshore floating platform (10), an operator controls the hydraulic actuator of the corridor bridge according to the position of the lapping point, so that the tip point of the corridor bridge reaches a suitable position above the lapping point of the offshore floating platform (10); B. The operator starts the force-position control system of the corridor bridge, the motion compensation control unit of the force-position control system controls the tip point of the corridor bridge to track the desired following position, so that the tip point of the corridor bridge follows the lapping point and ensures that the relative position of the tip point and the lapping point remains unchanged; C. After the tip point of the corridor bridge lapping on the lapping point of the offshore floating platform (10), the motion compensation control unit of the force-position control system controls the tip point of the corridor bridge to follow the lapping point; at the same time, the force control unit of the force-position control system obtains a following desired position correction amount for eliminating the three-dimensional contact force deviation between the tip point of the corridor bridge and the lapping point through the impedance controller, which is used to correct the following desired position received by the motion compensation control unit, and the motion compensation control unit controls the tip point of the corridor bridge to track the corrected following desired position, so that the tip point of the corridor bridge and the lapping point maintain a constant desired three-dimensional contact force.

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