CN101285730A - One-dimensional mooring line and riser dynamic characteristics test device - Google Patents

Abstract

A device for testing the dynamic characteristics of mooring cables and risers of marine structures in the field of marine engineering technology, including a sliding mooring cable and riser test platform, a shore rail support, a replaceable brake lever, and an AC servo motor control system and pool bottom equidistant anchor points, etc. The shore rail bracket is fixed on the bank of the pool, the sliding mooring cable and the riser test platform are placed in the shore rail bracket track, and the shore rail bracket and the sliding mooring cable are horizontally connected through a replaceable brake lever And the riser test platform to fix the sliding mooring line and the riser test platform, the AC servo motor control system controls the slider sliding on the sliding mooring line and the riser test platform, the sliding mooring line and the riser test platform The lower end of the slider is tied with a mooring cable or a riser model, and the other end of the mooring cable or a riser model is fixed on an equidistant anchor point at the bottom of the pool. The invention overcomes the disadvantages of difficulty in changing a large horizontal span, poor control precision and difficult operation.

Description

One-dimensional mooring line and riser dynamic characteristics test device

technical field

The invention relates to a device in the field of marine engineering, in particular to a one-dimensional mooring cable and riser dynamic characteristic test device.

Background technique

Actual engineering experience proves that the mooring system is very important to the motion response of marine structures, and how to accurately predict the motion response of the mooring system has become a major topic in the field of ocean engineering today. When conducting model tests on deepwater platforms or FPSOs, correctly simulating their mooring lines and riser devices plays a vital role in the accuracy of the tests. Ideally, the physical characteristics of the mooring lines and risers in the model tests need to be all realistic. Under current circumstances, checking whether the mooring line model or the riser model meets the requirements mainly depends on the top tension-displacement characteristics of the model, that is, whether the static displacement characteristics meet the expected requirements, and seldom considers the dynamics of the mooring line or riser The characteristics are similar. In the past, it was considered that the horizontal oscillation velocity of the mooring structure was very small, and the dynamic effect of the mooring line could be ignored, but only the static force of the mooring line was considered. However, relevant studies have shown that mooring lines have a greater impact on the slow-swing damping of mooring structures, and the dynamic characteristics of mooring lines have attracted more and more researchers' interest.

After searching the literature of the prior art, it was found that Chen Xiaohong and Huang Xianglu mentioned a method to study the mooring line dynamics in the "Double Frequency Response Function for Measuring Mooring Line Dynamics by Random Oscillation Method" published in the fifth issue of "Journal of Shanghai Jiao Tong University" in 1995. The characteristic test is carried out in a tank with a length of 12m, a width of 0.4m, and a depth of 0.75m. The upper-end computer and DC motor equipment input the one-dimensional horizontal movement of the upper end of the mooring line, and measure the dynamic horizontal displacement and tension of the end point of the mooring line. The test has the following disadvantages: (1) The movement between the motor spindle and the worktable is transmitted through the intermediate link such as the screw. It is easy to produce elastic deformation, friction, backlash, etc., which will cause the lag of feed motion and many other nonlinear errors, which will affect the rapid response to motion commands. At the same time, the lead screw is a slender rod, which will be deformed under the action of force and heat, which will affect the processing accuracy. (2) It is necessary to manually move the test platform to change the large horizontal span, which is time-consuming and laborious; (3) The mooring cable and riser test platform are placed in the water tank as a whole, the height is limited, and the water depth is difficult to control; (4) The accuracy of the DC servo motor Lower, can not precisely control the slide block motion; In further searching, do not find identical or similar literature with subject matter of the present invention.

Contents of the invention

The purpose of the present invention is to overcome the deficiencies of the prior art and provide a one-dimensional mooring line and riser dynamic characteristic testing device. On the basis of the prior art, the present invention installs pulleys at the bottom of the mooring cable and riser test platform, designs the bracket track, arranges equidistant anchor points at the bottom of the pool, etc., and designs gears and cogged tracks to make the test more convenient to change the level Span; through the overall design of the pool bank, the water depth can be adjusted by lifting the false bottom of the pool, making the test easier to operate; by replacing the original DC motor with the AC servo motor system and PCI servo motion control card, the test accuracy is greatly improved; through the improvement The original screw transmission device is replaced by the gear and cogged track design, which improves the motion control accuracy.

The present invention is realized through the following technical schemes, the present invention includes: sliding mooring cable and riser test platform, shore rail support, replaceable brake lever, AC servo motor control system, mooring cable and riser model As well as equidistant anchor points at the bottom of the pool, the shore rail bracket is fixed on the shore of the pool, the sliding mooring cable and the riser test platform are placed in the shore rail bracket track, and the shore rail is horizontally connected through a replaceable brake lever Type support and sliding mooring line and riser test platform to fix the sliding mooring line and riser test platform, the AC servo motor control system controls the slider movement on the sliding mooring line and riser test platform, the sliding type The lower end of the slider of the mooring line and riser test platform is tied with a mooring line or a riser model, and the other end of the mooring line or riser model is fixed on an equidistant anchor point at the bottom of the pool.

The sliding mooring cable and riser test platform includes: four pulleys, a slide rail, slider, gear, cogged track, coupling, motor support, scale pointer, two supporting steel plates and water entry rod, The connection method is as follows: a slide rail and cogged track are fixed between two supporting steel plates, four pulleys are symmetrically installed on the lower surface of the two supporting steel plates, and at the same time slide freely on the bank rail bracket, and the sliding mooring cable is used to And the replaceable brake lever between the riser test platform and the left end support side of the shore rail support realizes the braking of the sliding mooring cable and the riser test platform; the sliding mooring cable and the motor support of the riser test platform Place the AC servo motor, the AC servo motor is connected to the gear through the coupling, the gear rotates on the cogged track, the slider spans the slide rail, the AC servo motor of the AC servo motor control system can output motion modes similar to sine, Drive the gear to rotate, the gear reacts on the AC servo motor, the motor is fixed on the motor support, the motor support and the slider are connected together to drive the slider to move, the lower end of the slider is connected to the water inlet rod, and the lower end of the water inlet rod is connected to the six-component force sensor , displacement sensors and mooring cables or risers, so as to control the one-dimensional movement of the upper end of the mooring cables or risers. At the same time, a scale pointer is installed in the middle of the slider, and the scale pointer points to the shore wall scale.

The shore track type support includes: a chute track and a shore wall scale. The chute track provides the sliding track required by the sliding mooring cable and the pulley of the standpipe test platform, which is the main part of the shore rail support; the shore wall scale is marked on the bank of the pool to indicate the slide type Relative displacement of mooring lines and riser test platform. The quay wall scale is parallel to the chute track and is located at the projection position of the chute track on the quay wall. By sliding the entire sliding mooring line and riser test platform, a larger horizontal span can be achieved, that is, a larger slow drift can be achieved. Research on the dynamic characteristics of mooring lines and risers.

The replaceable brake rods include connecting rods of different sizes, and the connecting rods are fixed by sliding mooring cables and bolts and nuts on the standpipe test platform and the support side of the shore track-type bracket, so as to achieve the purpose of braking the movement of the platform system. During the test, the sliding mooring line and riser test platform must be fixed, and only the slider is allowed to drive the mooring line or riser to move, so the sliding mooring line and riser test platform must be fixed. Fixing bolts are welded to the left end of the sliding mooring cable and riser test platform and the support plate at the left end of the shore rail support for fixing the connecting rod. When studying the dynamic characteristics under a small horizontal slow drift distance, it can be realized by moving the slider position; when studying the dynamic characteristics under a medium or large slow drift distance, it is necessary to combine the mobile sliding mooring line and riser test platform and Slider implementation. When the mobile sliding mooring line and riser test platform are moved to a certain position, they can be fixed with replaceable brake rods.

The AC servo motor control system includes a set of PCI servo motion control cards and a set of AC servo motors. The control process is as follows: the PCI servo motion control card accepts the instructions from the computer to control the rotation of the AC servo motor, and the AC servo motor is axially connected with the sliding mooring cable and the gear on the standpipe test platform to ensure the synchronization of motion.

The equidistant anchor points at the bottom of the pool include 8 anchor points at the bottom of the pool, such as 0m, 2m, 4m, 6m, ... 14m. Extend the corresponding distance along the bank wall of the pool. When the span of the bank rail support cannot meet the horizontal slow drift span of the mooring cable, a larger horizontal span can be achieved by changing the equidistant anchor points at the bottom of the pool to achieve a greater degree. Research on dynamics under slow drift distance.

The mooring cable and riser models include mooring cable and riser models of various diameters, materials, and lengths, and their characteristics are made according to a certain scale reduction according to the actual mooring cables and risers.

The overall bank design, sliding mooring cable and riser test platform design, gear, cogged track design and AC servo motor control system design of the present invention overcome the shortcomings of difficulty in changing a large horizontal span, poor control accuracy, and difficult operation. , which can be better used in the dynamic characteristic test of mooring lines and risers of marine structures. Considering the material characteristics, since the shore track support needs to support the sliding mooring line and the riser test platform, the rigidity requirement is high, and a steel structure is required; at the same time, due to the design of the replaceable connecting rod, the movement of the test platform is avoided. Sliding mooring lines and riser test platforms can be made from lighter materials, making them easier to handle. Since the movement of the slider depends on the transmission of the gears, the slider needs to be made of particularly lightweight materials. The present invention can be used for dynamic testing of mooring lines or risers in various forms, including catenary type, tension type and the like.

Description of drawings

Figure 1 is a flow chart of the AC servo motor control system

Figure 2 is the overall layout of the shore

Figure 3 is the structural diagram of the shore rail support

Figure 4 is a schematic diagram of the sliding mooring line and riser test platform system

Figure 5 is a schematic diagram of the overall structure

In the figure: pool bank 1, false bottom 2, bank track support 3, chute track 4, shore wall scale 5, sliding mooring cable and riser test platform 6, slider 7, scale pointer 8, water entry rod 9. Couplings 10, gears 11, slide rails 12, replaceable brake levers 13, pulleys 14, supporting steel plates 15, equidistant anchor points at the bottom of the pool 16, mooring lines or riser models 17 and AC servo motor control system 18, tooth groove track 19, motor support 20.

Detailed ways

The embodiments of the present invention are described in detail below in conjunction with the accompanying drawings: this embodiment is implemented on the premise of the technical solution of the present invention, and detailed implementation methods and specific operating procedures are provided, but the protection scope of the present invention is not limited to the following the described embodiment.

As shown in Figure 5, this example includes: shore rail support 3, sliding mooring cable and riser test platform 6, replaceable brake lever 13, mooring cable or riser model 17, and isometric anchors at the bottom of the pool Point 16 and AC servo motor control system 18 and so on. The connection method is: the bank rail bracket 3 is fixed on the bank of the pool, the sliding mooring cable and the riser test platform 6 are placed on the bank rail bracket 3, and the 18-axis AC servo motor control system is connected to the sliding mooring cable And the riser test platform 6, the sliding mooring line and the riser test platform 6 are connected to the equidistant anchor point 16 at the bottom of the pool through the mooring line or the riser model 17.

As shown in Figure 2, the bank track support 3 is fixed on the bank of the pool, the sliding mooring cable and riser test platform 6 are placed on the bank track support 3, and the sliding mooring cable and riser test platform 6 The equidistant anchor points 16 at the bottom of the pool on the false bottom 2 are connected by mooring lines or riser models 17 .

As shown in Figure 4, the sliding mooring line and riser test platform 6 includes: slider 7, scale pointer 8, water entry rod 9, coupling 10, gear 11, slide rail 12, four pulleys 14, two The supporting steel plate 15, the cogged track 19, the motor support 20, etc., are connected as follows: the sliding mooring line and the standpipe test platform 6 are placed on the chute track 4 as a whole, the sliding mooring line and the standpipe test platform 6 The AC servo motor control system 18 is connected through the coupling 10, the motor is installed on the motor support 20, and is used to control the movement of the gear 11, and the gear 11 moves horizontally and one-dimensionally on the chute track 19, thereby driving the sliding mooring rope and The slider 7 on the riser test platform oscillates, the lower end of the slider 7 is riveted into the water rod 9, the water rod 9 is attached to the mooring line or the riser model 17, and the other end of the mooring line or the riser model 17 is fixed at the bottom of the pool at an equal distance Anchor point 16 on.

Described slide rail 12 and tooth groove track 19 are fixed between two support steel plates 15, and chute track 19 is positioned at the groove in the middle of slide rail 12, and four pulleys 14 are symmetrically installed on two support steel plate 15 lower surfaces, simultaneously Sliding freely on the shore track type support 3, the platform braking is realized by the replaceable brake lever 13 between the sliding mooring cable and the standpipe test platform 6 and the left end support edge of the shore track type support 3.

The slider 7 straddles the slide rail 12, and there is a certain distance between the upper and lower planes of the slider 12 and the slide rail. The AC servo motor of the AC servo motor control system 18 can output a motion mode similar to sine, and through the coupling 10 drives the gear 11 to move, and the gear 11 moves one-dimensionally on the cogged track 19, thereby driving the slider 7 to move one-dimensionally on the slide rail 12.

The lower end of the water entry rod 9 is connected with a six-component force sensor and a displacement sensor, so as to control the one-dimensional movement of the upper end of the mooring cable or riser. At the same time, a scale pointer 8 is installed at the middle position of the slider 7, and the scale pointer 8 points to the rail-type support on the shore. 3 in the wall scale 5.

The motor support 20 is used to support the motor and to transmit the one-dimensional motion of the gear 11 to the slider 7 .

The total length of the sliding mooring line and riser test platform is 1350mm, and the maximum stroke of the slider is 1150m.

As shown in FIG. 3 , the shore rail support 3 includes: a chute rail 4 and a shore wall scale 5 . The chute track 4 can provide the sliding track for the sliding mooring line and the riser test platform 6, and the shore wall scale 5 is a group of scales with a unit of 5 centimeters engraved on the pool wall for indicating the sliding The relative positions of mooring lines and riser test platform 6. The midpoint of the chute track 4 is vertically above the anchor point 0m at the bottom of the pool.

The total length of the bank track-type support 3 is 6m, and it is necessary to ensure that the chute track 4 is parallel to the horizontal plane during installation, and no obvious inclination is allowed.

Described chute track 4 is long and is 6m.

As shown in FIG. 1 , the AC servo motor control system 18 is composed of a set of PCI servo motion control cards and a set of AC servo motors. The control process is: the computer sends instructions to the PCI servo motion control card, the servo motion control card controls the rotation of the AC servo motor, and the AC servo motor is connected to the sliding mooring cable and the coupling 10 of the standpipe test platform 6 to ensure that its motion is coaxial , the AC servo motor drives the gear 11 to rotate.

The PCI motion control card is a 4-axis stepping pulse servo motion control card based on PCI bus technology, which is used in conventional precise motion control. It simplifies the stepping and pulse servo motion control, which can significantly improve the motion performance of the motor. The card adopts MCX314 motion ASIC chip, which can provide various motion control functions, such as 2/3-axis linear interpolation, 2-circle circular interpolation, T/S curve acceleration/acceleration, etc. In addition, when the PCI PCI motion control card performs these motion control functions to control the motor, it will not increase the burden on the processor. The AC servo motor adopts Mitsubishi HC-KFS AC servo motor with a power of 750W and MR-J2S AC servo.

The replaceable brake rod 13 can manufacture rods of different lengths as required. The brake lever is fixed between the left side of the sliding mooring cable and the standpipe test platform 6 and the support plate on the left side of the bank rail support 3 by bolts and nuts. Considering the actual needs of the test device, make a file every 500mm, and you can make 600mm, 1100mm, 1600mm (the center of the sliding mooring line and riser test platform 6 is located above the anchor point 0m, this rod can be used), 2100mm, 2600mm and other 5 pieces brake lever.

When measuring the dynamic characteristics of a certain mooring line or riser according to the research plan, first fix the bracket at the corresponding position on the bank of the pool according to the above, and adjust the position of the sliding mooring line and riser test platform 6 so that the midpoint is located at the track type. The middle position of the support 3, that is, the bottom of the pool is equidistant from the vertical top of 0m from the anchor point 16. Utilize replaceable brake rod 13 to fix sliding type mooring line and riser test platform 6, make its track direction fixed. The AC servo motor control system 18 is adjusted to ensure that it outputs the desired oscillatory motion. The AC servo motor control system 18 controls the movement of the gear 11 through the coupling 10 of the sliding mooring line and the riser test platform 6, and the gear 11 oscillates on the cogged track 20 to drive the sliding mooring line and the riser test platform 6. The upper slider 7 makes one-dimensional oscillating motion in the direction of the track. The lower end of the slider 7 is riveted into the water rod 9. The water rod 9 is connected to the mooring line or the riser model 17, and the other end of the mooring line or the riser model 17 is fixed on the bottom of the pool. Isometric anchors 16 on. A six-component force sensor and a displacement sensor can be installed on the top of the mooring line and the riser model 17, and by analyzing and recording the data of the six-component force sensor and the displacement sensor, the motion curve and the dynamic force curve of the upper end point of the mooring line or riser can be obtained, It can be used to further study the hydrodynamic coefficient of mooring lines and risers, etc.

When it is necessary to study the dynamic characteristics of mooring lines and risers in the case of moderate or large-scale slow drift, the sliding mooring line and riser test platform 6 can be moved left or right to the designated position, and the scale on the slider 7 can be passed. The pointer 8 is positioned, and the appropriate brake lever 13 is replaced to fix the sliding mooring line and the standpipe test platform 6 at the same time. When the extreme position of the shore track support 3 still cannot meet the horizontal span, the position of the anchor point 16 at the bottom of the pool can be replaced, such as moving from the position of 2m to the position of 4m or 6m at the bottom of the pool.

Claims (10)

1. A one-dimensional mooring cable and riser dynamic characteristic test device, characterized in that it includes: a sliding mooring cable and riser test platform, a shore rail support, a replaceable brake lever, and an AC servo motor control system , the mooring cable and riser model, and the equidistant anchor points at the bottom of the pool, wherein: the shore track support is fixed on the bank of the pool, and the sliding mooring line and riser test platform is placed in the bank track support track. The replaceable brake lever is horizontally connected to the shore rail support and the sliding mooring line and riser test platform to fix the sliding mooring line and riser test platform, and the AC servo motor control system controls the sliding mooring line and riser The slider on the test platform slides, and the lower end of the slider of the sliding mooring line and riser test platform is attached to the mooring line or the riser model, and the other end of the mooring line or the riser model is fixed on the equidistant anchor point at the bottom of the pool . 2. The one-dimensional mooring line and riser dynamic characteristic test device according to claim 1, wherein the sliding mooring line and riser test platform comprises: four pulleys, a slide rail, a slider, Gears, couplings, cogged rails, scale pointers, two supporting steel plates and water inlet rods, slide rails and cogged rails are fixed between the two supporting steel plates, four pulley pairs are set on the lower surface of the two supporting steel plates, and the motor Installed on the motor support, the motor and the gear are connected through a coupling, the motor support and the slider are connected together, the slider spans the slide rail, the lower end of the slider is connected to the water rod, and the lower end of the water rod is connected to the mooring cable and For the riser model, a scale pointer is installed in the middle of the slider. 3. The one-dimensional mooring line and standpipe dynamic characteristic test device according to claim 2, characterized in that the four pulley pairs slide freely on the shore track support at the same time, and the sliding mooring line and standpipe The replaceable brake lever between the tube test platform and the left end support edge of the shore rail support realizes the braking of the sliding mooring line and the riser test platform. 4. The one-dimensional mooring cable and riser dynamic characteristic test device according to claim 2, characterized in that the lower end of the water entry rod is connected to a six-component force sensor and a displacement sensor, and the six-component force sensor and displacement sensor are installed on the mooring At the top of the cable and riser model, by analyzing and recording the six-component force sensor data and displacement sensor data, the motion curve and dynamic force curve of the upper end point of the mooring cable or riser are obtained. 5. The one-dimensional mooring cable and standpipe dynamic characteristic test device according to claim 1, wherein the bank rail-type support includes: a chute track, a bank scale, and the bank scale is marked on the pool wall , the quay wall scale is used to indicate the relative displacement of the sliding mooring line and the riser test platform on the shore rail support. The quay wall scale is parallel to the chute track and is located at the projected position of the chute track on the quay wall. 6. The one-dimensional mooring line and standpipe dynamic characteristic test device according to claim 5, wherein the chute track of the bank rail support is parallel to the horizontal plane, and the chute track provides a sliding mooring line and The sliding track required for the pulley of the riser test platform. 7. The one-dimensional mooring line and riser dynamic characteristic test device according to claim 1 or 6, characterized in that, the scale pointer in the sliding mooring line and riser test platform points to the bank rail support shore wall scale. 8. The one-dimensional mooring line and riser dynamic characteristic test device according to claim 1, wherein the replaceable brake lever includes connecting rods of various scales, and the connecting rod passes through the sliding mooring line and riser. The bolts and nuts on the support side of the test platform and the shore track-type bracket are fixed. 9. The one-dimensional mooring line and riser dynamic characteristic test device according to claim 1, wherein the AC servo motor control system includes a set of PCI servo motion control card and a set of AC servo motor, and the PCI servo motion The control card accepts the instructions sent by the computer to control the rotation of the AC servo motor. The AC servo motor and the gear are connected through a coupling to ensure that their movement is coaxial, and the rotation of the AC servo motor drives the gear to move. 10. The one-dimensional mooring line and riser dynamic characteristic test device according to claim 1, characterized in that, the equidistant anchor points at the bottom of the pool include 0m, 2m, 4m, 6m, ... 14m, etc. There are 8 anchor points at the bottom of the pool, the 0m point is vertically below the midpoint of the bank rail support, and the other points extend corresponding distances along the bank wall of the pool.

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