Marine intelligent test device

Abstract

The invention provides a marine intelligent test device, which comprises a heave measurement unit, a tension detection device, a winch, a telescopic mechanism and a control unit, and is characterized in that the heave measurement unit is used for measuring a heave signal of a ship body and transmitting the heave signal of the ship body to the control unit; the winch is used for winding and unwinding a cable, the telescopic mechanism comprises a pulley block used for guiding the cable, the pulley block is installed on a telescopic beam, the telescopic beam is connected with a telescopic driving device used for driving the telescopic beam to horizontally move, and the cable of the winch penetrates through the pulley block on the telescopic mechanism to be connected with a tested object; the tension detection device is used for detecting the tension on the cable and transmitting a tension signal to the control unit; and the control unit is used for receiving the heave signal and the tension signal, outputting a first control signal to the winch according to the heave signal and the tension signal so as to realize winding and unwinding of the cable, and outputting a second control signal to the telescopic driving device so as to realize expansion or retraction of the telescopic beam.

Description

TECHNICAL FIELD

[0001] The present application relates to smart ocean intelligent equipment, in particular to a marine intelligent test device. BACKGROUND

[0002] In the development process of underwater detection equipment, in order to fully verify its performance, in addition to a large number of tests in inland waters such as lakes, various sea tests verification including wharf and real ship test are also needed. The underwater detection equipment adopts the shipborne flexible lifting method, which needs to be frequently retracted and released in actual use. If there is no intelligent retraction and release operation system, the test process will become very difficult and unsafe. On the other hand, when the underwater detection equipment is laid in the water for testing, its depth will change frequently due to the influence of sea waves and currents, and the performance of the equipment cannot be fully utilized. SUMMARY

[0003] The present application aims to solve at least one of the technical problems existing in the prior art, and proposes a marine intelligent test device.

[0004] The embodiment of the present application provides a marine intelligent test device, which comprises:

[0005] A heave measuring unit is used for measuring the heave signal of the ship body and transmitting the heave signal of the ship body to the control unit;

[0006] A winch is used for realizing the retraction and release of the cable, and the winch is electrically connected with the control unit;

[0007] A telescopic mechanism comprises a pulley block used for guiding the cable, the pulley block is installed on a telescopic beam, the telescopic beam is connected with a telescopic driving device used for driving the horizontal movement of the telescopic beam, the cable of the winch passes through the pulley block on the telescopic mechanism and is connected with the tested product, and the telescopic driving device is electrically connected with the control unit;

[0008] A tension detection device is used for detecting the tension on the cable and transmitting the tension signal to the control unit;

[0009] The control unit is used for receiving the heave signal and the tension signal, and outputting a first control signal to the winch to realize the retraction and release of the cable and outputting a second control signal to the telescopic driving device to realize the expansion or retraction of the telescopic beam according to the heave signal and the tension signal.

[0010] In some embodiments, the control unit is provided with a main control chain feedforward compensation chain, a feedback control chain, the feedforward compensation chain comprising a feedforward prediction module, a comprehensive heave displacement conversion module and a feedforward controller arranged in sequence, the feedforward prediction module being configured to receive a ship body heave signal measured by a heave measuring unit in real time, and obtain a ship body motion prediction signal according to the ship body heave signal, the comprehensive heave displacement conversion module being configured to convert the ship body motion prediction signal into a vertical comprehensive heave displacement of a cable extension point, and the feedforward controller being configured to generate a feedforward compensation amount according to the vertical comprehensive heave displacement, and superimpose the feedforward compensation amount on the main control chain.

[0011] The main control chain comprises a first comparison module, a trajectory tracking controller, a main superimposition module and an actuator arranged in sequence, the first comparison module being configured to subtract a command displacement from a load displacement fed back by the feedback control chain to obtain a tracking error, the trajectory tracking controller being configured to obtain a basic control amount according to the tracking error, and the main superimposition module being configured to superimpose the feedforward compensation amount output by the feedforward controller and the basic control amount to obtain a total control amount, and output the total control amount to the winch to drive the winch to wind or unwind the cable.

[0012] In some embodiments, the feedforward compensation chain further comprises a data processing module, the data processing module being configured to perform smoothing interpolation processing on the ship body motion prediction signal, and output the ship body motion prediction signal to the comprehensive heave displacement conversion module.

[0013] In some embodiments, the feedforward compensation chain further comprises a first feedforward superimposition module, the first feedforward superimposition module being configured to superimpose the ship body heave signal and an inertial navigation measurement error to obtain a first superimposed signal, and transmit the first superimposed signal to the feedforward prediction module, the feedforward prediction module being configured to obtain the ship body motion prediction signal according to the first superimposed signal, and the inertial navigation measurement error comprising a measurement element error and a lever arm error.

[0014] In some embodiments, the feedforward compensation chain further comprises a second feedforward superimposition module, the second feedforward superimposition module being configured to superimpose the ship body motion prediction signal and a wave prediction error to obtain a second superimposed signal, and transmit the second superimposed signal to the comprehensive heave displacement conversion module, the comprehensive heave displacement conversion module being configured to convert the second superimposed signal into the comprehensive heave displacement, and the wave prediction error comprising a roll error, a pitch error and a heave error.

[0015] In some embodiments, the system further comprises a speed detection device, the speed detection device being configured to detect a rotating speed of a drum of the winch, and transmit a rotating speed signal to the control unit.

[0016] In some embodiments, a transfer function of the feedforward controller is: , wherein, is a motor torque constant, is a moment coefficient, is a motor electrical constant, is a winch radius.

[0017] In some embodiments, the main control chain further comprises a second comparison module for differencing the total control quantity with a rotational speed feedback signal to obtain an error signal, and a rotational speed controller for generating a motor control signal according to the error signal to adjust the rotational speed / torque of the motor of the winch.

[0018] In some embodiments, the transfer function of the rotational speed controller is: , wherein, is a motor torque constant, is a moment coefficient, is a motor electrical constant.

[0019] In some embodiments, the feedback control chain is configured to obtain a tension signal on the cable and a length of the cable from the point of extension to the load, and obtain the load displacement according to the tension signal, the vertical integrated heave displacement, and the length of the cable from the point of extension to the load.

[0020] In some embodiments, the feedback control chain comprises a state observer configured to obtain an estimated value of the change in length of the cable according to the length of the cable from the point of extension to the test object and the tension of the cable, and an operation module configured to sum the estimated value of the change in length of the cable with the vertical integrated heave displacement, and to subtract the length of the cable from the point of extension to the test object to obtain the load displacement, and feed back the load displacement to the comparison module.

[0021] In some embodiments, the feedforward prediction module is configured to obtain historical vertical displacement compensation quantities at a plurality of time points in the past, and to obtain a polynomial describing the heave motion according to the historical vertical displacement compensation quantities at the plurality of time points in the past, and to obtain a prediction signal of the ship body motion at a future time point through the polynomial.

[0022] In some embodiments, the polynomial expression Y(j) = a + b*(2+0.1*j) + c*(2+0.1*j)*(2+0.1*j) + d*(2+0.1*j)*(2+0.1*j)*(2+0.1*j), wherein a = 0.167*(3*x0+4*x1-x2); b = 0.167*(y2-y1); c = 0.056*(5*x2-3*x0-2*x1); d = 0.167 * (8 * y1 - y2); x0 = data3; x1 = 0.5 * (data4 + data2); y1 = 0.5 * (data4 - data2); x2 = 0.5 * (data5 + data1); y2 = 0.5 * (data5 + data1); data1, data2, data3, data4, data5, data6 are the historical vertical displacement compensation amounts of the last 6 time points, and j defines the discrete time point in the future.

[0023] In some embodiments, the control unit is further configured to receive a deployment instruction, control the extension beam of the telescopic mechanism to be deployed, and synchronously control the winch to deploy the cable, so that the winch and the telescopic mechanism operate synchronously; after the extension beam is deployed to the position, the telescopic mechanism is controlled to stop operating, and after the test object reaches the preset depth, the winch is controlled to stop deploying the cable.

[0024] The control unit is further configured to receive a cable-retrieving instruction, control the winch to retrieve the cable, after the test object reaches the preset height, control the extension beam of the telescopic mechanism to be retracted, and synchronously control the winch to retrieve the cable, so that the winch and the telescopic mechanism operate synchronously; after the extension beam is retracted to the position, the telescopic mechanism is controlled to stop operating, and the winch is controlled to stop retrieving the cable.

[0025] In some embodiments, during the synchronous deployment and retrieval of the winch and the telescopic mechanism, the movement speed Vj of the winch and the movement speed Vs of the telescopic mechanism satisfy the following relationship: , simplified as a, simplified as b, that is , wherein M is the distance that the telescopic mechanism has operated, H is the vertical distance from the telescopic mechanism to the rotation center of the winch, and T is time.

[0026] The present application has at least the following beneficial effects:

[0027] The shipborne intelligent test device provided by the present application has certain automatic deployment and retrieval capability, can simulate the actual deployment and retrieval process of the test object on the ship, and avoids the tediousness, insecurity and low efficiency of manual operation.

[0028] In order to ensure that the extension beam of the telescopic mechanism does not contact other objects during the extension and retraction process, the winch is cooperatively controlled when the telescopic mechanism is extended and retracted.

[0029] In another aspect, the ship intelligent test device provided by the application also has certain heave compensation capability, which can effectively offset the influence of sea waves on the depth of the towed test object.

[0030] The control unit of the application comprises a main control chain, a feedforward compensation chain and a feedback control chain. The feedforward controller D(s) of the feedforward compensation chain compensates the heave and motion disturbance (such as the vertical / horizontal motion of the ship body caused by sea waves) in advance by synthesizing heave displacement filtering and B-spline interpolation, and actively offsets the influence of the disturbance on the system. The state observer of the feedback control chain estimates the internal states such as cable length change and load displacement in real time, and provides accurate state feedback for the controller, solving the problem that the key variables are difficult to measure directly. The closed-loop trajectory tracking controller G(s) of the main control chain further corrects the model deviation and unknown disturbance through the error closed loop of the command displacement-feedback displacement, and ensures that the test object accurately tracks the target trajectory.

[0031] The heave change is the core disturbance of the vertical motion of the ship body (such as the up-down fluctuation of the top end of the crane caused by sea waves). The system realizes fast response through feedforward compensation+state observation. The “prediction-advance compensation” feature of the feedforward control, combined with the “real-time state estimation” of the state observer, makes the system respond more quickly to dynamic disturbances such as ship heave and test object mutation. Even in the face of model parameter changes, the negative feedback mechanism of the closed-loop structure and the state observer can maintain the stability of the system.

[0032] In summary, the control unit has a three-layer architecture of “feedforward advance compensation+state observation real-time correction+closed-loop tracking”, which not only ensures the anti-disturbance capability and control accuracy, but also has the ability to quickly respond to dynamic changes such as ship heave. The “double-path” design of feedforward and feedback reduces the impact of single-link failure on overall control. BRIEF DESCRIPTION OF DRAWINGS

[0033] Figure 1 A schematic diagram of a ship intelligent test device provided by the embodiment of the present disclosure is provided.

[0034] Figure 2 A system block diagram of heave compensation control of an embodiment provided by the embodiment of the present disclosure is provided.

[0035] Figure 3 Another system block diagram of heave compensation control provided by the embodiment of the present disclosure is provided.

[0036] Figure 4 Still another system block diagram of heave compensation control provided by the embodiment of the present disclosure is provided.

[0037] Figure 5 A whole flowchart of a prediction algorithm provided by the embodiment of the present disclosure is provided.

[0038] Figure 6 Another schematic diagram of the intelligent test device for ships provided by the embodiment of the present application (including a fixed coordinate system and a motion coordinate system);

[0039] Figure 7 A workflow diagram of the simulation of the laying cabin provided by the embodiment of the present application;

[0040] Figure 8 A schematic diagram of the simulation of the laying of the cable provided by the embodiment of the present application;

[0041] Figure 9 The actual vertical comprehensive heave displacement curve diagram provided by the embodiment of the present application. DETAILED DESCRIPTION

[0042] In order for those skilled in the art to better understand the technical solutions of the present application, the following describes exemplary embodiments of the present application in conjunction with the accompanying drawings, which include various details of the embodiments of the present application to help understanding, and should be considered only as exemplary. Therefore, those of ordinary skill in the art should realize that various changes and modifications can be made to the embodiments described herein without departing from the scope and spirit of the present application. Also, for the sake of clarity and conciseness, the description below omits the description of well-known functions and structures.

[0043] In the case of no conflict, the embodiments of the present application and the features in the embodiments can be combined with each other.

[0044] As used herein, the term "and / or" includes any and all combinations of one or more of the associated listed items.

[0045] The terms used herein are only used to describe specific embodiments, and are not intended to limit the present application. As used herein, the singular forms "a" and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will also be understood that the terms "comprise" and / or "consist of", when used in this specification, specify the presence of stated features, integers, steps, operations, elements, and / or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and / or groups thereof. The terms "connected" or "coupled" and / or similar terms are not limited to a physical or mechanical connection, but can include an electrical connection, whether direct or indirect.

[0046] Unless otherwise defined, all terms used herein, including technical and scientific terms, have the same meaning as commonly understood by one of ordinary skill in the art. It will also be understood that terms, such as those defined in commonly used dictionaries, should be interpreted as having a meaning that is consistent with their meaning in the context of the relevant art and the present application, and will not be interpreted in an idealized or overly formal sense unless expressly so defined herein.

[0047] Referring to Figure 1 The embodiment of the present application discloses a marine intelligent test device, comprising:

[0048] A heave measuring unit is configured to measure a heave signal of a ship body and transmit the heave signal of the ship body to a control unit;

[0049] A winch is configured to realize the winding and unwinding of a cable, and the winch is electrically connected to the control unit;

[0050] A telescopic mechanism comprises a pulley block configured to guide the cable, the pulley block is installed on a telescopic beam, the telescopic beam is connected to a telescopic driving device configured to drive the horizontal movement of the telescopic beam, the cable of the winch passes through the pulley block on the telescopic mechanism and is connected to a test object, and the telescopic driving device is electrically connected to the control unit;

[0051] A tension detection device is configured to detect the tension on the cable and transmit a tension signal to the control unit;

[0052] The control unit is configured to receive the heave signal and the tension signal, output a first control signal to the winch to realize the winding and unwinding of the cable, and output a second control signal to the telescopic driving device to realize the expansion or retraction of the telescopic beam.

[0053] The marine intelligent test device can control the deployment and recovery of the test object (such as an underwater detection device), and coordinate the operation of the winch and the telescopic mechanism during the deployment and recovery process; and can realize heave simulation and heave compensation control of the test object.

[0054] In some embodiments, the winch is designed as a single-layer winding drum, and the cable is wound around one layer when it is fully retracted, and the effective length of the winding drum is set as Therefore, it can be known that: , In the formula, L is the cable length, d is the diameter of the cable groove, and D is the diameter of the cable drum. In the formula, L is the cable length, d is the diameter of the cable groove, and D is the diameter of the cable drum.

[0055] In some embodiments, the servo motor is provided with an encoder, which can be used for measuring the stroke of the cable of the winch and collected by the control unit.

[0056] In some embodiments, a deployment control module and / or a heave compensation control module are arranged in the control unit, the deployment control module is configured to automatically deploy and recover the external test object, and the heave compensation control module is configured to realize automatic heave compensation.

[0057] In some embodiments, a steering mechanism is further arranged between the winch and the telescopic mechanism, and the steering mechanism comprises a steering wheel which is rotatably installed on a support.

[0058] The telescopic mechanism further comprises a mounting rack, and the telescopic beam is mounted on the mounting rack and in sliding fit with the mounting rack.

[0059] The winch, the steering mechanism and the telescopic mechanism are all mounted in the laying cabin. Figure 7 An analog laying cabin working flowchart is provided for the embodiment of the present application; see Figure 7 The general working flow of the analog laying cabin is as follows: first, the test equipment enters the cabin, the cabin is hoisted onto a vehicle and transported to a test site; the cabin is hoisted and laid to a position suitable for carrying out tests, such as the stern of a ship, and test preparation is completed. Then the cabin door is opened, the sonar wet end is laid to a predetermined depth through the laying control module, and relevant tests are carried out. In the test process, in order to ensure test effect, the heave compensation control module is started, the heave, roll and pitch parameters of the system are measured according to the heave sensing unit fixed on the winch unit, the parameters are fed back to the control unit, the winch cable is adjusted through the control unit, so that the sonar wet end is controlled within a certain depth error range. At the same time in the test process, the underwater attitude sensor monitors the sonar wet end and transmits the attitude data back for display. After the test is completed, the sonar wet end is recovered through the laying control module, the cabin door and window are closed, power is cut off, and the site is withdrawn.

[0060] In some embodiments, the laying control module is used to receive a user's laying instruction, control the telescopic beam of the telescopic mechanism to be unfolded, and synchronously control the winch to pay out the cable. After the telescopic beam is unfolded to the position, the telescopic mechanism is controlled to stop running. After the test object reaches the preset depth, the winch is controlled to stop paying out the cable.

[0061] The laying control module is used to receive a user's cable retraction instruction, control the winch to retract the cable, and after the test object reaches the preset height, control the telescopic beam of the telescopic mechanism to be retracted, synchronously control the winch to retract the cable, and after the telescopic beam is retracted to the position, control the telescopic mechanism to stop running and control the winch to stop retracting the cable.

[0062] In some embodiments, the shipborne intelligent test device of the present application further comprises an instruction input device, and the instruction input device is connected with the control unit. The instruction input device can adopt a switch or / and a touch screen.

[0063] The present application can realize analog deployment by manual electric control mode, and the mode selection switch is set to "manual" mode. The deployment process is as follows: first, manually open the electric door, manually collect the cable to hoist the equipment to a safe height, then select the high / low speed mode through the speed selection switch, select the deployment mode through the operation selection switch, control the expansion of the telescopic beam of the telescopic mechanism, and synchronously control the cable winding of the winch. After the telescopic beam is expanded to the position, the telescopic mechanism stops running, and the deployment / recovery selection switch is set to the middle position. The winch is manually wound, and when the preset depth is reached, the cable winding / cable collection selection switch is set to the middle position, the winch stops winding, and the analog deployment process is ended.

[0064] The recovery process is as follows: first, manually select the cable collection mode, and when the cable collection reaches a height that can be retracted, select the high / low speed mode through the speed selection switch, then select the recovery mode through the operation selection switch, control the telescopic beam of the telescopic mechanism to retract, and synchronously control the cable winding of the winch. After the telescopic beam is retracted to the position, the telescopic mechanism stops running, and the deployment / recovery selection switch is set to the middle position. The winch is manually wound, the equipment is placed on the bottom plate of the shelter, the initial state is restored, the cable winding / cable collection selection switch is set to the middle position, the winch stops winding, the electric door is closed, and the analog recovery process is ended. The manual control panel is also provided with an emergency stop button to realize system emergency stop operation in emergency state.

[0065] In order to ensure that the telescopic rod does not contact other objects during extension and retraction, the winch is cooperatively controlled during the telescopic operation of the telescopic mechanism, that is, the deployment control module of the present application needs to realize cooperative control of the winch and the telescopic mechanism. The cable length L from the winch to the pulley, the linear displacement of the telescopic mechanism movement and the vertical distance H of the telescopic mechanism from the rotation center of the winch have a trigonometric function relationship as shown in Figure 8 . Figure 8 In the figure, M is the distance that the telescopic mechanism has been moved; P is the distance of the next movement of the telescopic mechanism; L1 is the distance of the cable to the pulley; L2 is the distance of the cable to the pulley after the next movement of the telescopic mechanism is completed; Vj is the movement speed of the winch; and Vs is the movement speed of the telescopic mechanism.

[0066] In some embodiments, during the synchronous operation of the winch and the telescopic mechanism for deployment and recovery, the movement speed Vj of the winch and the movement speed Vs of the telescopic mechanism satisfy the following relationship: , wherein M, H and T are known constants, which can be simplified as a, which can be simplified as b, that is .

[0067] The relationship between the winch pay-off speed and time T and the telescopic mechanism speed can be obtained from the above, and the winch output speed is given according to the above calculation result, so that the winch pay-off speed and the telescopic mechanism speed are synchronized, and the safety of the load is ensured.

[0068] In some embodiments, the cable is drawn out from the winch, extends to the external device through the tensioning wheel and the fixed pulley. The cable is retracted and paid out through the motor and the speed reducer, and the speed and position are compensated in real time through the IMU, the tension sensor and the like.

[0069] The attitude measurement unit (IMU) is an inertial measurement unit that can measure the states of three degrees of freedom of the ship body in real time and give the current attitude speed. Through mathematical modeling of the compensation device, the change amount of the ship body heave degree of freedom corresponding to the change of each degree of freedom attitude can be calculated, and the change amount is applied to the winch device in real time, so that the height change caused by the ship body motion is offset, and the heave compensation effect is achieved.

[0070] The tension sensor has two purposes, one is to keep the tension at a certain constant value during control, and the other is to control the constant tension during cable retraction. The function of the tension detection device is to detect the tension change on the cable, and the tension sensor is an important element of the device. The tension sensor detects the tension on the cable in real time, converts the tension change into an electrical signal, and the sensor sends the electrical signal to the control unit.

[0071] The function of the servo motor is to drive the winch to place the device at the required depth under the water bottom, and to receive the control signal of the control unit and drive the winch to realize the retraction and pay-out of the cable, so as to achieve the wave compensation function.

[0072] The winch body is mainly composed of a servo motor, a drum, a speed reducer and the like. The servo motor drives the drum to realize the safe retraction and pay-out of the cable. The full load state of the servo motor is the state of retracting the device, and the load of the servo motor is smaller under the wave compensation.

[0073] The telescopic mechanism is provided with a limit sensor at the front end, which is used for wet end cable retraction anti-collision limiting to prevent the load from colliding with and damaging the upper end fixed pulley.

[0074] In some embodiments, the ship intelligent test device of the present application further comprises a speed detection device, which is configured to detect the rotating speed of the drum of the winch body, and then send an electrical signal to the control unit. The control unit determines the position and speed of the device in the wave according to the electrical signal, and decides whether to switch the working condition to retract and pay-out the cable.

[0075] The heave compensation of the application adopts an active compound compensation mode, considers that the load of the compensation object is small (60-200 kg), and selects an electric control driving mode for the compensation driving mode. Through heave compensation dynamics modeling and a control algorithm, corresponding control software is formed, and a heave compensation winch realizes high residual compensation precision, can well offset the influence of sea wave heave on the stability of the wet end of the sonar, and can effectively guarantee the verification of various detection performance indexes and use performance indexes of the sonar.

[0076] The ship will produce six degrees of freedom motion of sway, surge, heave and roll, pitch, yaw under the action of sea waves, and various operation systems and auxiliary systems on the ship body will also produce heave motion, at this time, high load will affect the ship operation, and great operation loss and safety hidden danger will also be caused. For underwater hoisting, because the cable length and water resistance are relatively large, swinging situation generally does not occur. However, the ship motion caused by sea waves will cause the dramatic change of cable tension, among which the influence of ship heave on cable tension is the most significant. When the tension change exceeds the design limit, the cable may break. Therefore, in order to guarantee the safety of offshore operation, certain technical means must be adopted to compensate the influence of ship motion.

[0077] The ship sailing in the wind and waves will produce six degrees of freedom motion of yaw, roll, pitch, sway, surge and heave (heave), combined with the actual use of the test equipment, the heave compensation system needs to compensate the cable length, and the cable length can be decomposed into vertical and horizontal directions. For the vertical direction of the ship stern, the most influential is the motion of two degrees of freedom of pitch and heave, and for the horizontal direction of the ship stern, the most influential is the motion of two degrees of freedom of yaw and sway. The scheme adopts inertial navigation to measure the total heave and sway motion of the ship stern, wherein the heave motion is the superposition of the vertical components of the two motions of pitch and heave, and the sway motion is the superposition of the horizontal components of the two motions of yaw and sway.

[0078] The scheme plans to adopt a rotating type heave compensation device in the form of a winch, establishes a complete mathematical model of the heave compensation system, introduces the multi-closed loop idea in the electric drive system into the heave compensation control system, constructs a control structure containing three closed loops, analyzes the dynamic characteristics from the frequency domain, and gives the design method of the three controllers. In order to obtain accurate depth setting precision, the application also constructs a state observer based on cable tension detection, and fully considers the feasibility of physical implementation.

[0079] The active heave compensation system is a winch heave compensation system, which keeps the equipment pulled by the bow and stern of the ship at the same depth on the seabed through the motor winding and unwinding winch. Considering the feasibility of practical application, the design constructs a motion reference unit to measure the heave motion of the ship body in real time, takes the heave displacement of the ship body as a measurable disturbance, applies the structure invariance principle to design a feedforward compensator, and improves the compensation precision of the system.

[0080] The heave signal of the ship can be collected by the inertial navigation sensor arranged near the winch to obtain the posture change of the ship, and the posture change in the heave direction, the posture change speed and acceleration are calculated through coordinate transformation, and the output signal of the acceleration sensor is used to eliminate the interference of zero drift, zero offset and high frequency noise.

[0081] The tension sensor is used to detect the dynamic tension of the cable in real time. The equipment placed in the water during the heave of the ship will change the tension of the cable due to the traction of the cable. The tension sensor detects the force of the cable during traction and feeds back the signal to the control system.

[0082] The control unit is used to collect the heave motion acceleration signal and the tension signal of the ship, and perform mathematical processing such as smoothing, filtering and integration on the collected signals to obtain the speed and displacement of the heave motion of the ship, and calculate the control amount of the electric winch through the PID control algorithm.

[0083] In some embodiments, referring to Figures 2 to 4 , the heave compensation control module includes a main control chain, a feedforward compensation chain and a feedback control chain. The feedforward compensation chain includes a feedforward prediction module, a comprehensive heave displacement conversion module and a feedforward controller arranged in sequence. The feedforward prediction module is used to receive the ship body heave signal measured by the heave measuring unit in real time, and obtain a prediction signal of the ship body motion (a prediction signal of the ship body motion in the next control period) according to the ship body heave signal. The comprehensive heave displacement conversion module is used to convert the prediction signal of the ship body motion to obtain the vertical comprehensive heave displacement of the cable extension point M (such as but not limited to the top end of the crane). The feedforward controller is used to generate a feedforward compensation amount according to the vertical comprehensive heave displacement, and superimpose the feedforward compensation amount on the main control chain.

[0084] The main control chain includes a first comparison module, a trajectory tracking controller, a main superposition module and an actuator arranged in sequence. The first comparison module is used to subtract the instruction displacement from the load displacement feedback by the feedback control chain to obtain a tracking error. The trajectory tracking controller is used to obtain a basic control amount according to the tracking error. The main superposition module is used to superimpose the feedforward compensation amount output by the feedforward controller and the basic control amount to obtain a total control amount, and output the total control amount to the winch to drive the winch to reel in or out the cable.

[0085] Since the active heave compensation control unit is a position disturbance system, simple closed-loop control is difficult to achieve good control effect. Therefore, according to the principle of structural invariance, the system designs a feedforward controller to suppress the ship motion disturbance. The ship motion signal measured by the inertial navigation attitude sensor is input to the AR prediction model after low-pass filtering, and the future motion trend of the ship body is obtained. Through the feedforward controller, it is superimposed into the closed-loop control loop and output to the control unit to control the servo motor, so that the servo motor can wind the cable in advance to eliminate other attitude disturbances.

[0086] In some embodiments, the feedforward prediction module is configured to obtain a history of vertical displacement compensation amounts at a plurality of time points in the past, i.e., history of heave compensation calculation results, and obtain a polynomial describing heave motion according to the history of vertical displacement compensation amounts at the plurality of time points in the past, and obtain a prediction signal of ship motion at a future time point through the polynomial.

[0087] In some embodiments, the polynomial expression cha_value[j]=a+b*(2+0.1*j)+c*(2+0.1*j)*(2+0.1*j)+d*(2+0.1*j)*(2+0.1*j)*(2+0.1*j), wherein a=0.167*(3*x0+4*x1-x2); b=0.167*(y2-y1); c=0.056*(5*x2-3*x0-2*x1); d=0.167*(8*y1-y2); x0=data3; x1=0.5*(data4+data2); y1=0.5*(data4-data2); x2=0.5*(data5+data1); y2=0.5*(data5+data1); data1, data2, data3, data4, data5, data6 are history of vertical displacement compensation amounts at a plurality of time points in the past, i.e., history of heave compensation calculation results, and j defines a discrete time point in the future.

[0088] The heave compensation prediction displacement amount slash_cha=cha_value[j] at a future time point (determined by j);

[0089] The predicted speed slash_vol=b+4*c+12*d;

[0090] The predicted acceleration slash_acc=2*c+12*d.

[0091] By predicting the displacement amount through heave compensation, the ship body motion signal at this moment can be reversely deduced, such as the 6 signal key features of the heave measuring unit. The 6 signal of the heave measuring unit (especially Heave, Roll and Pitch) is the “source data” for calculating the real-time compensation amount.

[0092] The present application obtains the rotation angle and the translation distance of the ship body around the rotation angle and the translation distance , the rotation angle and the translation distance , the rotation angle and the translation distance , the rotation angle and the translation distance , and then the coordinate data in the fixed reference system is obtained through coordinate transformation.

[0093] According to the coordinate data in the fixed reference system, the heave displacement, that is, the Z-axis position offset caused by heave motion, is calculated; and the vertical displacement compensation amount is obtained according to the heave displacement.

[0094] The ship body motion data in the fixed reference system is obtained through coordinate transformation, including: constructing a rotation transformation matrix, rotating the original motion system coordinates (Wheel_Point_m[0 / 1 / 2]) according to the rotation transformation matrix, adding the translation transformation vector to the rotated coordinates, and finally obtaining the ship body motion data Wheel_Point_f[0 / 1 / 2] in the fixed reference system. The subsequent calculation of delta_l (vertical difference value between the fixed system and the motion system), heave_convert (heave displacement), and the motion prediction based thereon are all based on the fixed reference system data.

[0095] lo=SQRT((Wheel_Point_m[0]-Top_Point_f[0])*(Wheel_Point_m[0]-Top_Point_f[0])+(Wheel_Point_m[1]-Top_Point_f[1])*(Wheel_Point_m[1]-Top_Point_f[1])+(Wheel_Point_m[2]-Top_Point_f[2])*(Wheel_Point_m[2]-Top_Point_f[2]))).

[0096] l = SQRT((Wheel_Point_f[0]-Top_Point_f[0])*(Wheel_Point_f[0]-Top_Point_f[0])+(Wheel_Point_f[1]-Top_Point_f[1])*(Wheel_Point_f[1]-Top_Point_f[1])+(Wheel_Point_f[2]-Top_Point_f[2])*(Wheel_Point_f[2]-Top_Point_f[2]))).

[0097] Fixed system and the vertical difference between the moving system delta_l = Wheel_Point_f[2] - Wheel_Point_m[2].

[0098] Heave displacement heave_convert = A * delta_l. A is the proportional coefficient of the actual heave physical quantity. In some embodiments, A is 3.6.

[0099] The present application also includes: batch storage of N (such as 6) historical vertical displacement compensation quantities, and automatic switching to the "calculation state" after storage, that is, obtaining a polynomial describing the heave motion according to the historical vertical displacement compensation quantities at the last N (such as 6) time points.

[0100] The predicted signal of the ship body motion at the future time point is obtained through the polynomial.

[0101] The historical vertical displacement compensation quantities at multiple time points are sequentially stored in the array present_data, specifically:

[0102] When the system is in the "data saving state", the following operations are performed:

[0103] The current input historical vertical displacement compensation quantity slash is stored in the i-th position of the array present_data (i is the array index, starting from 0).

[0104] The index i is incremented by 1 to prepare for storing the next slash value.

[0105] It is judged whether 6 data have been stored:

[0106] If i < 6 (not full), the "data saving state" is maintained, and the next slash value is continuously received and stored. If i ≥ 6 (6 data are stored), the state is switched to the "calculation state", that is, a polynomial describing the heave motion is obtained according to the historical vertical displacement compensation quantities at the last N (such as 6) time points.

[0107] The flag slash_flag is used to mark that the data is full, so that other logic (such as a calculation module) can determine whether to start processing.

[0108] The above method of the present application realizes "sliding window data collection". By counting i, it ensures that the present_data array always stores "the slash data of the last 6 time points" (from present_data[0] to present_data[5]). After being full, the state switching is triggered automatically, which connects the "data calculation" process and is the key link of the "collection-processing" closed loop, ensuring that the subsequent calculation has enough historical data support (such as fitting a polynomial using the 6 data in the code).

[0109] The present application also controls the number of "future motion prediction" through the counting variable j, and updates the historical data array after completing the prediction, forming a "calculation-update-re-calculation" closed loop. The specific analysis is as follows:

[0110] J is the "index of future time" (range 1~M), which corresponds to the M discrete future time points that need to be predicted (such as t=2.1 to t=3.0, interval 0.1 unit time).

[0111] When j<M (not completed M time point prediction): j is incremented by 1, and the state.calculate state is maintained to continue calculating the prediction value (cha_value[j]) of the next future time point.

[0112] When j≥M (M time point prediction has been completed): theoretically, it switches to the state.update state (update data).

[0113] In some embodiments, M is 10.

[0114] Regardless of whether j is less than M (such as M is 10), it will eventually enter the state.update state (redundant logic in code design to "ensure timely data update", avoiding state stuck due to j counting abnormality).

[0115] The state.update state (update data) includes updating the historical data array to prepare for the next round of prediction.

[0116] Array left shift: through the loop of k=1~4, the elements of index 1~4 in present_data are updated to the values of index 2~5 (i.e. "left shift one bit"), which is equivalent to discarding the oldest historical data (present_data[0], which is no longer used in subsequent calculation).

[0117] Supplement new data: store the latest input data slash in present_data[5] (the end of the array), so that present_data always maintains "the history data of the last 6 time points".

[0118] Reset the count and state: j is reset to 1 (start from the beginning to calculate the prediction of the next 10 future time points), the state is switched back to state.calculate, and the next round of prediction is started.

[0119] The above process of the application is: using the current 6 history data to calculate the prediction value of 10 future time points → discarding the oldest data, supplementing new data, and resetting the count → returning to state.calculate, i.e. continuing to predict the next batch of 10 future time points based on the updated 6 history data.

[0120] The above scheme of the application realizes continuous and real-time prediction of ship motion through "rolling update of history data + repeated prediction of future time points", j controls the calculation of the prediction value of 10 future time points each time, and after completion, it is forced to enter the data update state; state.update maintains the latest 6 history data through "left shift array + supplement of new data", and continues the next round of prediction after resetting the count; the whole forms a closed loop of "real-time data → future prediction → data update", which guarantees the continuity and timeliness of the motion prediction.

[0121] In some embodiments, the feedforward compensation chain further comprises a data processing module for performing smoothing interpolation processing on the prediction signal of the ship motion and outputting to the comprehensive heave displacement conversion module.

[0122] In some embodiments, the feedforward compensation chain further comprises a first feedforward superposition module for superimposing the ship heave signal and the inertial navigation measurement error to obtain a first superposition signal, and transmitting the first superposition signal to the feedforward prediction module, the feedforward prediction module is used to obtain the prediction signal of the ship motion according to the first superposition signal, and the inertial navigation measurement error includes measurement element error and lever arm error.

[0123] In some embodiments, the feedforward compensation chain further comprises a second feedforward superposition module for superimposing the prediction signal of the ship motion and the wave prediction error to obtain a second superposition signal, and transmitting the second superposition signal to the comprehensive heave displacement conversion module, the comprehensive heave displacement conversion module is used to convert the second superposition signal into a comprehensive heave displacement, and the wave prediction error includes roll error, pitch error and heave error.

[0124] In some embodiments, the intelligent test device for marine application further comprises a speed detection device for detecting the rotating speed of the winch body, and then sending an electric signal to the control unit, which judges the position and speed of the device in the wave and decides whether to switch the working condition and release or wind the cable.

[0125] In some embodiments, the main control chain further comprises a second comparison module for subtracting the total control amount from the rotating speed feedback signal to obtain an error signal, and a rotating speed controller for generating a motor control signal according to the error signal to adjust the rotating speed / torque of the motor of the winch.

[0126] The rotating speed feedback signal is the rotating speed detected by the speed detection device.

[0127] In some embodiments, the feedback control chain is used to obtain the tension signal on the cable and the length of the cable from the extension point to the test object (or the length of the cable released), and obtain the load displacement according to the tension signal, the vertical comprehensive heave displacement and the length of the cable from the extension point to the test object (or the length of the cable released).

[0128] In some embodiments, the feedback control chain comprises a state observer for obtaining an estimated value of the length change of the cable according to the length of the cable from the extension point to the load , the tension F of the cable , and an operation module for summing the estimated value of the length change of the cable and the vertical comprehensive heave displacement and subtracting the length of the cable from the extension point to the load to obtain the estimated load displacement (that is, the estimated value of the load displacement), and feeding back the estimated load displacement to the comparison module.

[0129] In other embodiments, the feedback control chain can also not have a state observer, but can collect the load displacement through a motor encoder or an encoder at the pulley. That is, the present application can detect the angle of rotation of the motor through the motor encoder to calculate the length of the cable in real time and the load displacement, or can detect the angle of rotation of the pulley through the encoder to calculate the length of the cable in real time and the load displacement.

[0130] In other embodiments, the feedforward prediction module adopts a prediction algorithm based on an AR model. The principle of the AR prediction model is to read the historical ship motion data, obtain the approximate curve of these signals through fitting, and finally predict the ship in the future for a certain time through the curve obtained by fitting.

[0131] The present application adopts attitude displacement compensation and ship speed compensation to weaken the influence of heave, in order to weaken the disturbance caused by ship displacement. Since the original signal of inertial navigation will have a certain delay, and the sampling rate is low, the present application designs a polynomial feedforward prediction algorithm based on time sequence, which can deduce the motion trend of the current or even future ship body according to the historical wave signal, and through the feedforward controller, the system can take action in advance to offset the adverse effects caused by time lag and large inertia characteristics.

[0132] The present application can also detect the angle of the pulley rotation through the encoder, and calculate the length of the cable in real time.

[0133] In some embodiments, the predicted signal of ship motion further comprises the following steps before displacement conversion: performing a smooth interpolation processing on the predicted signal of ship motion.

[0134] In some embodiments, the predicted signal of ship motion is obtained according to the ship heave signal, and specifically comprises: inputting the ship heave signal into an AR prediction model to obtain the predicted signal of ship motion.

[0135] In a short time range, the vertical motion of the test product caused by the ship motion can be regarded as a stationary random process, and the vertical displacement thereof obeys the following AR prediction model: , Wherein: - the order of the AR model; - the autoregressive coefficient of the AR model; - white noise sequence.

[0136] The key to obtaining an AR prediction model with high accuracy is to estimate the autoregressive coefficient of the model . Here we use the least squares method to estimate the vector of autoregressive coefficient according to the historical data, and the estimated vector is .

[0137] After completing the estimation of the autoregressive coefficient , the order of the AR model needs to be obtained to get the complete AR prediction model. The solution of the order is also called the order determination of the AR model.

[0138] The system selects the AIC criterion order determination method. First, the maximum order of the model is determined by offline estimation method. Then the order is taken from 1 to , and each order ​The autoregressive coefficients in the AR model are estimated by least square method, and the AIC criterion number of each model is calculated . Finally, the size of all is compared, and when there is one , , , it is the order of the AR prediction model.

[0139] After obtaining the autoregressive coefficients and order of the AR model through historical data, the predicted wave data of the future steps are : When , there is:

[0140] When , there is:

[0141] When , there is:

[0142] The overall flow chart of the wave prediction algorithm is shown in Figure 5 .

[0143] Because the ship has roll and pitch, the heave displacement of each point on the ship is not the same. The inertial measurement unit used to measure the change of the ship's pose is usually installed on the deck rather than the top of the crane, so a corresponding coordinate transformation is needed to convert the data measured by the inertial measurement unit into the vertical heave displacement of the top of the crane, otherwise there will be a large error.

[0144] In the system, the real-time attitude of the ship motion is read through inertial navigation to obtain real-time data of wave disturbance. The wave disturbance is acting on the six degrees of freedom of the ship, including the roll, pitch and heave of the ship. We need to obtain the disturbance of the wave in the vertical direction to the cable contraction point through conversion.

[0145] The system needs to determine the mathematical relationship between the cable length and the ship attitude through the motion law of the inertial navigation measurement data. Considering the convenience of calculation, two coordinate systems are established, as shown in Figure 6 .

[0146] The motion coordinate system P is fixed to the ship and moves with the ship. The origin of the coordinate system coincides with the origin of the inertial navigation, and is simply referred to as the body coordinate system or the dynamic coordinate system; the fixed coordinate system O is relatively static with respect to the earth, and is simply referred to as the static coordinate system or the fixed coordinate system. The dynamic coordinate system and the static coordinate system are coincident at the initial position.

[0147] Assume that the inertial measurement unit measures the rotation angle of the ship body around at this time , and the translation distance is , around Rotation angle is Translation distance is , around Rotation angle is Translation distance is The ship's current motion attitude is obtained, and a coordinate system is established with the location of the inertial measurement unit after the motion as the origin. At this point, from the coordinate system To coordinate system The rotation transformation matrix is: .

[0148] For ease of writing, for abbreviation, for The abbreviation for .

[0149] From coordinate system To coordinate system The translation transformation vector is:

[0150] Let point M be the location of the cable retraction point, and let the coordinates of M in coordinate system P be... The hull can be considered a rigid structure, when point Exercise until the point , when the point Exercise until the point At this point In coordinate system The coordinates in are .

[0151] Then point The coordinates in coordinate system P (or static coordinate system) are:

[0152] Let the obtained coordinates be... Then, the combined vertical heave displacement caused by the ship's motion at the cable retraction point is:

[0153] When at rest, the origin can be obtained in coordinate system P, and the coordinates of point P are: The coordinates of point M are The unit is meters.

[0154] Assume the ship moves to the coordinate system In the middle of the time, there was for , for Because the relative position of M to the ship body is invariable, the coordinates of M in the coordinate system .

[0155] The coordinates of M in the coordinate system , the coordinates of point M in the coordinate system P are:

[0156] The coordinates of M in the coordinate system 1.82. If the heave of the installation position point is used to replace the heave of the out-rope point, the following is obtained: .

[0157] In some embodiments, after obtaining the total control quantity, the method further comprises the steps of: subtracting the total control quantity from the rotation speed feedback signal to obtain an error signal, generating a motor control signal according to the error signal, and adjusting the rotation speed / torque of the motor of the winch.

[0158] In some embodiments, the motor control signal is generated according to the error signal, specifically comprising: inputting the error signal into a rotation speed controller to obtain the motor control signal.

[0159] Rotation speed controller design: according to the system model, for the rotation speed loop of the servo motor, the open-loop transfer function is:

[0160] In order to realize zero steady-state error of rotation speed and improve trajectory tracking accuracy, an integral link must be provided in front of the load disturbance action point, which should be included in the rotation speed controller. Therefore, the rotation speed controller adopts PI regulation, and the transfer function is:

[0161] In order to let the zero point of the controller and the large time constant pole of the control object be cancelled out, The control parameters of satisfy the condition: , Take , .

[0162] The rotation speed loop .

[0163] In some embodiments, the basic control quantity is obtained according to the tracking error, specifically comprising: inputting the tracking error into a trajectory tracking controller to obtain the basic control quantity.

[0164] ​​​​​Trajectory tracking controller design: further push the load displacement outer ring open-loop transfer function:

[0165] Neglect the influence of cable damping C, for the above formula The frequency characteristics are: .

[0166] The frequency characteristics are:

[0167] The approximate conditions for the above outer ring simplification are: the cutoff frequency And .

[0168] So the open-loop transfer function of the simplified position outer ring is: .

[0169] The system can use proportional control, and the proportional coefficient can be taken as .

[0170] In some embodiments, the feedforward compensation quantity is generated according to the vertical comprehensive heave displacement, specifically comprising: inputting the vertical comprehensive heave displacement into a feedforward controller to obtain a feedforward compensation quantity.

[0171] According to the principle of structural invariance, the expression of the feedforward controller can be obtained from the mathematical model of the system:

[0172] The above feedforward controller can theoretically completely compensate for the interference caused by ship motion, but the above feedforward controller has high order, as a preferred embodiment, in actual design, the third order term and the second order term can be omitted, only the differential term is retained, and the simplified feedforward controller is: , Wherein, is the motor torque constant, is the motor electrical constant, is the total inertia of the winch, reducer and the like converted to the motor output shaft, is the total viscous damping coefficient of the winch, reducer and the like converted to the motor output shaft, is the winch radius, is the reduction ratio, is the cable damping coefficient, is the cable stiffness coefficient, is the equivalent static tension, is the equivalent mass, is the mechanical efficiency.

[0173] The control unit's residual error is caused by a plurality of error sources, including inertial navigation measurement error , wave prediction error , error caused by the simplified feedforward controller , and error caused by the mechanism friction .

[0174] In some embodiments, the predicted signal of the ship body motion is obtained according to the ship body heave signal, specifically including: superimposing the ship body heave signal and the inertial navigation measurement error to obtain a first superimposed signal, and obtaining the predicted signal of the ship body motion according to the first superimposed signal. In some embodiments, the predicted signal of the ship body motion is subjected to displacement conversion, specifically including: superimposing the predicted signal of the ship body motion and the wave prediction error to obtain a second superimposed signal, and performing displacement conversion on the second superimposed signal to obtain the comprehensive heave displacement.

[0175] The inertial navigation measurement error and the wave prediction error include roll error, pitch error and heave error. The simplified feedforward controller. The total Coulomb friction torque converted to the motor output shaft.

[0176] The inertial navigation measurement error and the wave prediction error are superimposed and input into the comprehensive heave displacement conversion equation, which has: , wherein is the heave displacement conversion equation, is the ideal state of the ship's pose, is the actual state of the vertical comprehensive heave displacement of the cable extension point.

[0177] Further, the vertical comprehensive heave displacement of the cable extension point in the actual state is input into the simplified feedforward controller , and the error acting on the load displacement is: , wherein is the vertical comprehensive heave displacement of the cable extension point in the ideal state; is the common fraction of the two transfer functions; is the speed loop transfer function.

[0178] According to the system model, the error of the mechanism friction acting on the load displacement is:

[0179] The total error of the system is:

[0180] The inertial navigation measurement error includes measurement element error and lever arm error. The measurement element error is mainly caused by design principles, processing technology and assembly technology, etc. The measurement element error of the selected inertial navigation system is: the roll angle and pitch angle measurement accuracy is ± 0.03°, and the heave measurement accuracy is 5 cm or 5%.

[0181] The cause of the lever arm error: when the mass center of the inertial navigation system does not coincide with the mass center of the ship, if the ship has angular motion, due to the Lever arm effect, the output of the accelerometer contains the lever arm error.

[0182] According to the data, due to the Lever arm effect, the specific force at the position of the inertial navigation system and the specific force at the mass center of the ship have the following relationship: , is the specific force at the position of the inertial navigation system, is the specific force at the mass center of the ship, is the lever arm length, is the angular velocity of the ship relative to the inertial coordinate system.

[0183] The error term in it is .

[0184] Next, the parameters of and are determined. It can be approximately considered that the mass center of the ship is at the geometric center of the ship. The inertial navigation system is located on the stern deck. A rectangular coordinate system is established with the mass center of the ship as the origin, and .

[0185] According to the data, the roll amplitude of a large ship under extreme conditions is 30°, and the roll period is , where C is the roll period coefficient and can be taken as 0.8, B is the ship width and can be taken as 14.28 m, is the initial stability height and can be taken as 0.8 m, and is obtained. The roll motion can be approximated as a sinusoidal motion, and the roll angle .

[0186] The pitch amplitude of a large ship under extreme conditions is 20°, and the pitch period is , where is the pitch period coefficient and can be taken as 0.55, L is the ship length and can be taken as 100 m, and is obtained. The pitch motion can be approximated as a sinusoidal motion, and the roll angle .

[0187] Thus, the derivation of the roll and pitch angle can be calculated , .

[0188] Substituting can be calculated .

[0189] Thus, the displacement error caused by it is .

[0190] As a result, the inertial navigation measurement error includes measurement element error and rod arm error, so the inertial navigation measurement error vector is: .

[0191] In this system, the original signal of inertial navigation will have a certain delay, and the sampling rate is low, so we design a polynomial feedforward prediction algorithm based on time series, which can infer the current and even future ship motion trend according to the historical signal, and compensate to the control loop according to the system delay, to offset the adverse effects of time delay and large inertia on the system control.

[0192] When multi-step prediction is performed, the later prediction data is obtained based on the previous prediction data, so it is easy to cause error accumulation when long-term prediction is performed.

[0193] When the historical data sequence obeys a known prediction model, the prediction value of the heave displacement after steps is: (1) when , ; ; (2) when , ; Where p is the set order.

[0194] In this system, the sampling period T of inertial navigation is 0.01s, and the response time of the whole system is about estimated by experience, so two-step prediction is selected, and the prediction time is 0.02s. Using matlab for simulation analysis, taking the heave displacement signal as , the roll angle signal , and the pitch angle signal , the maximum heave displacement error is 0.0125m, the maximum roll angle error is​ For , the maximum value of the pitch angle error For .

[0195] As can be seen from the above, the wave prediction error includes the roll error, the pitch error and the heave error, so the wave prediction error vector is:

[0196] From the foregoing error transmission analysis, the inertial navigation measurement error and the wave prediction error are superimposed and input to the comprehensive heave displacement conversion equation to obtain the vertical comprehensive heave displacement of the cable extension point in the actual state . Then input to the simplified feedforward controller, and finally act on the load displacement .

[0197] Therefore, the vertical comprehensive heave displacement of the cable extension point in the actual state needs to be solved first. The ship's position and posture in the ideal state are , and the heave motion amplitude is 1.5 m. Due to the influence of the inertial navigation measurement error and the wave prediction error , the actual measured position and posture of the ship are:

[0198] According to the coordinate transformation, in the ideal state, the cable retraction point moves to , and the coordinates of in the static coordinate system P are:

[0199] At this time, the comprehensive vertical heave displacement of the cable retraction point caused by the ship's motion is:

[0200] However, in the actual situation, due to the existence of errors, the coordinates of in the static coordinate system P are:

[0201] The actual heave displacement obtained is: The vertical comprehensive heave displacement of the cable extension point in the actual state is Figure 9 as shown in .

[0202] Further, the vertical comprehensive heave displacement of the cable extension point in the actual state is Input to the simplified feedforward controller The error in the load displacement is: , where The maximum error .

[0203] The above is the error of the system caused by the wave signal with heave variation amplitude of 1.5 meters, and the error of the system caused by different wave signals is related to the heave variation amplitude, which is analyzed as follows. The ideal state of the ship is , and the heave amplitude is A.

[0204] In the ideal state, the cable contraction point moves to , and the coordinates in the static coordinate system P are:

[0205] In the actual situation, the coordinates in the static coordinate system P are: .

[0206] Obviously, there is not a simple proportional relationship between the amplitude and the residual error, and the invention uses matlab quadratic polynomial fitting to obtain , wherein represents the amplitude.

[0207] The coulomb friction existing in each transmission mechanism will also affect the control accuracy of the system, and for the system, the total coulomb friction can be expressed as: , wherein, is the friction torque converted to the output shaft of the servo motor, is the static friction converted to the output shaft, is the coulomb friction converted to the output shaft, is the angular velocity of the output shaft of the servo motor, is the Stribeck angular velocity.

[0208] Through the analysis of the data, it can be obtained that , , .

[0209] According to the mathematical model, it can be obtained that the error of the load displacement acted by the friction of the mechanism is: ​

[0210] rated speed of the motor i.e. error value for- m.

[0211] Through the above calculation and analysis, the total error of the system is:

[0212] When A=0.3m, the error is 0.047486m, which is less than 0.05m;

[0213] When A=0.5m, the error is 0.049486m, which is less than 0.05m;

[0214] When A=0.8m, the error is 0.065486m, and the residual error is 8.1%;

[0215] When A=1m, the error is 0.070486m, and the residual error is 7%;

[0216] When A=1.2m, the error is 0.076486m, and the residual error is 6.3%;

[0217] When A=1.5m, the error is 0.086m, and the residual error is 5.73%;

[0218] In summary, the residual error of the system meets the performance index requirements.

[0219] The control unit also collects the roll angle, pitch angle, azimuth angle, heave value, residual error and other data and feeds them back to the upper computer in real time.

[0220] The heave simulation is a sinusoidal heave signal actively generated by the system during testing, and is a working mode of the winch working state during reaction simulation heave compensation. The standard sinusoidal signal is automatically generated by the system software, and the amplitude and frequency can be set. The amplitude and frequency setting values are not greater than the maximum working capacity of the system.

[0221] The overall functional requirements of the marine intelligent test device are:

[0222] 1. Heave compensation operation can be started, and heave compensation operation is automatically performed according to the real-time change of heave;

[0223] 2. The cable tension signal can be collected, and when the tension exceeds the range, an alarm can be given and the winch can be controlled to stop urgently;

[0224] 3. The motor has a power-off brake function, which ensures that the test object does not continuously descend when the system suddenly loses power;

[0225] 4. The winch has a cable winding and unwinding limit;

[0226] 5. The extension and retraction of the telescopic mechanism can be controlled, the running speed is divided into high speed mode and low speed mode, and the telescopic mechanism limiting signal acquisition function is provided;

[0227] 6. It has the functions of emergency stop, automatic start / stop, etc.

[0228] Example embodiments have been disclosed herein and, although the use of specific terms is exemplified throughout, they are used in this context only and should not be construed as limiting in any manner. In some instances, it will be apparent to those skilled in the art that features, characteristics or / and elements described in connection with a particular embodiment can be used in conjunction with other embodiments unless otherwise explicitly stated. As such, those skilled in the art will appreciate that various changes can be made without departing from the scope of the application as set forth in the claims that follow.

Claims

1. A marine intelligent test system, characterized in that, The utility model relates to a kind of ship motion control system, including: heave measuring unit, the heave measuring unit is used to measure ship body heave signal, and the heave signal of ship body is passed to control unit; winch, the winch is used to realize the take-up of cable, the winch is electrically connected with control unit; retractable mechanism, the retractable mechanism includes for the pulley block of cable guiding, the pulley block is installed on retractable beam, the retractable beam is connected with retractable drive device for driving retractable beam horizontal movement, the cable of winch passes through the pulley block on retractable mechanism and is connected with test object, the retractable drive device is electrically connected with control unit; tension detection device, the tension detection device is used to detect tension on cable, and passes tension signal to control unit; control unit, the control unit is used to receive the heave signal, tension signal, and according to the heave signal, tension signal, output first control signal to winch, realize the take-up of cable;Output second control signal to retractable drive device, realize the deployment or retraction of retractable beam.

2. The system of claim 1, wherein: The control unit is provided with main control chain feedforward compensation chain, feedback control chain, the feedforward compensation chain includes the feedforward prediction module, integrated heave displacement conversion module and feedforward controller arranged in sequence, the feedforward prediction module is used to receive the heave signal of ship body that heave measuring unit real-time measurement, and according to ship body heave signal, obtain the forecast signal of ship motion, the integrated heave displacement conversion module is used to carry out displacement conversion to the forecast signal of ship motion, obtains the vertical integrated heave displacement of cable extension point, the feedforward controller is used to generate feedforward compensation according to the vertical integrated heave displacement, and the feedforward compensation is superimposed to main control chain; The main control chain includes the first comparison module, trajectory tracking controller, main superposition module and actuator arranged in sequence, the first comparison module is used to difference instruction displacement and the load displacement that feedback control chain feedback, obtains tracking error, the trajectory tracking controller is used to obtain basic control quantity according to the tracking error, the main superposition module is used to carry out superposition operation to the feedforward compensation of feedforward controller output and basic control quantity, obtains total control quantity, and is output to winch, drives winch to take-up cable.

3. The system of claim 2, wherein: The feedforward compensation chain further includes data processing module, and the data processing module is used for the forecast signal of ship motion carries out smooth interpolation processing, and is output to integrated heave displacement conversion module.

4. The system of claim 2, wherein: The feedforward compensation chain further includes first feedforward superposition module, the first feedforward superposition module is used to superimpose ship body heave signal and inertial navigation measurement error, obtains first superposition signal, and passes first superposition signal to feedforward prediction module, the feedforward prediction module is used to obtain the forecast signal of ship motion according to first superposition signal, and the inertial navigation measurement error includes measurement element error and lever error.

5. The system of claim 2, wherein: The feedforward compensation chain further comprises a second feedforward superposition module, configured to superimpose a predicted signal of the hull motion and a wave prediction error to obtain a second superposition signal, and transmit the second superposition signal to a comprehensive heave displacement conversion module, which is configured to convert the second superposition signal into a comprehensive heave displacement.

6. The system of claim 2, wherein: The main control chain further comprises a second comparison module and a rotating speed controller, the second comparison module is configured to subtract the total control quantity from the rotating speed feedback signal to obtain an error signal, and the rotating speed controller is configured to generate a motor control signal according to the error signal to adjust the rotating speed / torque of the motor of the winch.

7. The system of claim 2, wherein: The feedback control chain comprises a state observer and an operation module, the state observer is configured to obtain an estimated value of the length change of the cable according to the length of the cable from the cable extension point to the test object and the tension of the cable, and the operation module is configured to sum the estimated value of the length change of the cable and the vertical comprehensive heave displacement and subtract the length of the cable from the cable extension point to the test object to obtain a load displacement, and feed back the load displacement to the comparison module.

8. The system of claim 2, wherein: The feedforward prediction module is configured to obtain historical vertical displacement compensation quantities at a plurality of recent time points, and obtain a polynomial describing heave motion according to the historical vertical displacement compensation quantities at the plurality of recent time points, and obtain a predicted signal of the hull motion at a future time point through the polynomial.

9. The system of claim 8, wherein: The polynomial expression Y(j) is a+b*(2+0.1*j)+c*(2+0.1*j)*(2+0.1*j)+d*(2+0.1*j)*(2+0.1*j)*(2+0.1*j), wherein a=0.167*(3*x0+4*x1-x2); b=0.167*(y2-y1); c=0.056*(5*x2-3*x0-2*x1); d=0.167*(8*y1-y2); x0=data3; x1=0.5*(data4+data2); y1=0.5*(data4-data2); x2=0.5*(data5+data1); y2=0.5*(data5+data1); data1, data2, data3, data4, data5 and data6 are historical vertical displacement compensation quantities at the six most recent time points, and j defines a discrete time point in the future. The control unit is further configured to receive a deployment instruction, control the extension beam of the telescopic mechanism to be unfolded, and synchronously control the winch to deploy the cable, so that the winch and the telescopic mechanism operate synchronously to deploy; after the extension beam is unfolded to the position, the telescopic mechanism is controlled to stop operating, and after the test object reaches the preset depth, the winch is controlled to stop deploying the cable. The control unit is further configured to receive a cable recovery instruction, control the winch to recover the cable, after the test object reaches the preset height, control the extension beam of the telescopic mechanism to be retracted, and synchronously control the winch to recover the cable, so that the winch and the telescopic mechanism operate synchronously to recover, after the extension beam is retracted to the position, the telescopic mechanism is controlled to stop operating, and the winch is controlled to stop recovering the cable. ​ ​ ​ ​ ​ ​ ​ ​ ​ 10. The system of claim 1, wherein: ​ ​

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