A method for adjusting the position of a rigid raft supported by air bags

Abstract

The present application relates to the technical field of vibration and noise reduction of surface ships and underwater vehicles, and discloses a pose adjustment method for a rigid floating raft supported by air bags, comprising the following steps: (1) establishing a coordinate system of the air bag supported floating raft vibration isolation system, (2) determining the position parameters of measuring points, (3) establishing a plane equation of the raft frame, (4) calculating the optimal control pressure of the air bags, (5) analyzing the pose calculation results, and (6) selecting the air bags and air charging and discharging according to the optimal control pressure of each air bag obtained in step (4) and the pose calculation results obtained in step (5); when the raft frame pose reaches the control precision, the adjustment is ended; when the raft frame pose fails to reach the control precision, the pose adjustment is re-performed by returning to step (2); the method optimizes the raft frame pose control process, and makes the physical meaning of the raft frame adjustment process clearer.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of vibration and noise reduction of surface ships and underwater vehicles, and particularly relates to a position adjustment method for a rigid floating raft supported by air bags. BACKGROUND

[0002] Air bag vibration isolators are widely used in vibration isolation systems of surface ships and underwater vehicles due to their good low-frequency vibration isolation performance. However, due to the slow air leakage of the air bag itself and external disturbances, the floating raft supported by the air bag will deviate from the balanced posture, and the shafting connected to the floating raft will be misaligned. When the position of the floating raft deviates greatly from the balanced and aligned position, the shafting of the ship will be twisted and deformed, the control effect of the floating raft vibration isolation system will be reduced, and even the safety of the ship equipment will be threatened.

[0003] In the prior art, the process of solving the position of the floating raft supported by the air bag is usually described by the rotation angle around each axis, the translation component in each direction and other parameters, which are not concise and clear enough, and the sensor data analysis and processing efficiency is not high. The position control of the floating raft is usually divided into two processes of height adjustment and horizontal posture adjustment, and the control process is complicated, the position of the raft is not clear enough, and a suitable mathematical model is needed to support and optimize the process of solving the position of the floating raft supported by the air bag. SUMMARY

[0004] In view of the above defects or improvement needs of the prior art, the present application provides a position adjustment method for a rigid floating raft supported by air bags to solve the technical problems of the prior art that the process of controlling the position of the floating raft supported by air bags is complicated, the position measurement of the raft is not accurate enough, the adjustment strategy is not clear enough, the robustness of the system is not strong enough, and the measurement error is large

[0005] To achieve the above purpose, the present application provides the following technical scheme:

[0006] A position adjustment method for a rigid floating raft supported by air bags, comprising the following steps:

[0007] (1) Establishing a coordinate system of the air bag supported floating raft vibration isolation system: taking the air bag arrangement direction coinciding with the Y axis in the raft aligned state, the horizontal plane of the raft being perpendicular to the direction of the Y axis as the X axis, and the origin O of the coordinate system coinciding with the center of gravity of the floating raft, a coordinate system of the air bag supported floating raft vibration isolation system is established;

[0008] (2) Determining the position parameters of the measuring points: obtaining the coordinates of each measuring point on the raft in the system coordinate system of step (1), wherein X and Y depend on the installation position of each displacement sensor, and Z depends on the reading of each displacement sensor;

[0009] (3) Establishing the plane equation of the raft: fitting the plane equation of the raft by using the least square method on the coordinates of the measuring points in step (2), and establishing the plane equation of the raft;

[0010] (4) Pose solution result analysis: the plane equation of the raft is obtained from step (3) to analyze the pose solution result;

[0011] (5) Optimal control pressure of the air bag: the raft adjustment process is regarded as a quasi-static process, the torque balance equations of the air bag isolators around the X and Y axes and the force balance equation along the Z axis are obtained from the statics theory, and the optimal control pressure of each air bag is obtained;

[0012] (6) The pose solution result obtained from step (4) and the optimal control pressure of each air bag obtained from step (5) are used to select the air bag and the air charging and discharging, when the raft pose reaches the control accuracy, the adjustment is ended; when the raft pose cannot reach the control accuracy, the pose adjustment is re-performed in step (2).

[0013] As preferred, the specific steps of step (3) for establishing the plane equation of the raft include:

[0014] (31) The plane equation is established as:

[0015] Z=aX+bY+c

[0016] Wherein a, b, and c are unknown numbers;

[0017] (32) Random errors are added in the plane equation of step (31), then:

[0018] z i =Z i +v i

[0019] or z i =aX i +bY i +c+v i

[0020] In the formula, z i is the measured data, Z i is the true value, v i is the random error, i represents the number of the measuring point in the system, and i=1~8;

[0021] (33) The total error is obtained by adding the measurement error each time, then:

[0022]

[0023] (34) The optimization index function J is defined, the plane fitting is performed by using the least square method, and the best function matching of the data is found by minimizing the sum of squares of errors:

[0024]

[0025] The smaller J is, the better the plane fitting is, that is, the plane equation corresponding to the minimum of the optimization index function J is the plane equation of the raft.

[0026] Step (3) of establishing the plane equation of the raft further comprises:

[0027] (35) converting the plane equation obtained in step (34) into the solving of three unknowns, if J is minimized, the extreme value method is used to obtain:

[0028]

[0029] (36) further arranging the formula in step (35) to obtain:

[0030]

[0031] (37) converting the formula in step (36) into a matrix form to obtain:

[0032]

[0033] (38) solving the matrix equation in step (37) to obtain The obtained plane equation of the raft is:

[0034]

[0035] wherein, and indicate the inclination of the raft, the positive and negative of the actual height of the center of gravity of the raft and the ideal centering height indicate the size relationship.

[0036] As preferred, the analysis of the pose solution result in step (4) is:

[0037] According to the system coordinate system in step (1), the plane where the raft is located is divided into four quadrants, and the plane equation obtained in step (38) is combined to obtain:

[0038] ① if and , the first quadrant of the raft is the highest, and the third quadrant is the lowest;

[0039] ② if and , the second quadrant of the raft is the highest, and the fourth quadrant is the lowest;

[0040] ③ if and , the third quadrant of the raft is the highest, and the first quadrant is the lowest;

[0041] ④ if and​ The fourth quadrant of the raft frame has the highest height, and the second quadrant has the lowest height.

[0042] If the result is positive, it means that the center of gravity of the raft frame is above the ideal centering height; otherwise, the center of gravity of the raft frame is below the ideal centering height.

[0043] As preferred, the step (5) of obtaining the optimal control pressure of the air bag specifically includes the following steps:

[0044] (51) The adjustment process of the raft frame is regarded as a quasi-static process, and the moment balance equations of the air bag isolator around the X and Y axes and the force balance equation along the Z axis are obtained from the statics theory:

[0045]

[0046] wherein k represents the number of the air bag in the system, and k ∈ [1, 6], P k represents the pressure of the kth air bag, X k , Y k represents the coordinates of the kth air bag, S e represents the effective area of the air bag, and G represents the total weight of the raft air bag isolation system.

[0047] (52) The uniformity of the air bag pressure is increased as a constraint condition, and the variance of the pressure of each air bag is required to be minimized, i.e.:

[0048]

[0049] (53) The optimal control pressure P sk of each air bag is obtained on the basis of step (52), i.e.:

[0050]

[0051] As preferred, the selection order of the air bag and the inflation and deflation in step (6) is as follows: the quadrant is selected first, and then the air bag is selected, i.e. the corresponding quadrant is obtained from the analysis of the results of the position and posture calculation in step (4), and the air bag is selected in combination with the step (5) of obtaining the optimal control pressure of the air bag, i.e.:

[0052] When , ① if and , the air bag of the first quadrant is deflated;

[0053] ② if and , the air bag of the second quadrant is deflated;

[0054] ③ if and , the air bag of the third quadrant is deflated;

[0055] If and deflate the airbag in the fourth quadrant;

[0056] When , ① if and inflate the airbag in the third quadrant;

[0057] ② if and inflate the airbag in the fourth quadrant;

[0058] ③ if and inflate the airbag in the first quadrant;

[0059] ④ if and inflate the airbag in the second quadrant.

[0060] As a preferred, define the actual pressure and optimal pressure ratio parameter λ k to select the airbag most in need of control:

[0061]

[0062] When there are two or more airbags in any quadrant, numbered m1, m2, …, m n :

[0063] ① if and , deflate the airbag m r ;

[0064] ② if and , inflate the airbag m r ;

[0065] Wherein, m1, m2, …, m n represent each airbag in the system; n is the total number of airbags in the system, n≥2 and n is an integer; r represents the subscript of the airbag number in the system, r∈[1, n] and r is an integer.

[0066] As a preferred, when one or more displacement sensors fail, only the displacement sensor data at the corresponding position needs to be removed, and the remaining displacement sensor data is used to fit a new raft plane equation according to steps (1)-(6) to continue to realize the adjustment of the raft pose.

[0067] As a preferred, when one or more airbag inflation and deflation failures occur, the remaining non-faulty airbag inflation and deflation is used to realize the adjustment of the raft pose.

[0068] The present application has remarkable technical effects due to the above technical solutions.

[0069] (1) The raft pose control process is optimized, and the physical meaning of the raft adjustment process is clearer. The control strategy of the raft is combined with the mathematical model, and the raft obtains a mathematical expression more consistent with its actual physical meaning. Under the premise of the system regulation capacity, it can be adjusted to any pose, and the raft pose adjustment is more flexible and reliable.

[0070] (2) The complex raw data is simplified into a more clear and concise mathematical model, so that the data analysis and processing are more efficient and convenient.

[0071] (3) The noise and uncertainty in the sensor data are reduced, the stability and accuracy of the control algorithm are improved, the adjustment process is more stable, and the optimal fitting in the least square sense is realized.

[0072] (5) When the exact position of the center of gravity is not clear, as long as the approximate area where the center of gravity of the raft is located is determined, the raft attitude control algorithm can still converge.

[0073] (6) When one or more displacement sensors of the system fail, the pose solving strategy can still use the remaining fault-free displacement sensors to fit the raft pose.

[0074] (7) When one or more air bags fail to inflate or deflate, the pose adjustment strategy can still use the remaining fault-free air bags to inflate or deflate to adjust the raft pose. BRIEF DESCRIPTION OF DRAWINGS

[0075] Figure 1 It is a structural schematic diagram of the air bag supported rigid raft of the present application.

[0076] Figure 2 It is a pose adjustment control flowchart of the air bag supported rigid raft of the present application.

[0077] Figure 3 It is a raft pose solution result analysis schematic diagram.

[0078] Figure 4 It is an air bag and inflation and deflation selection schematic diagram.

[0079] In all the drawings, the same reference signs are used to represent the same elements or structures, wherein:

[0080] 1 - device; 2 - base; 3.1, 3.2, 3.3, 3.4, 3.5, 3.6 - air bags; 4.1, 4.2, 4.3, 4.4, 4.5, 4.6, 4.7, 4.8 - displacement sensors; 5.1, 5.2, 5.3, 5.4, 5.5, 5.6 - air bag pressure sensors; 6 - raft frame; 7.1, 7.2, 7.3, 7.4 - the position of each quadrant. DETAILED DESCRIPTION

[0081] In order to make the objectives, technical solutions and advantages of the present application clearer, the present application will be further described in detail below with reference to the accompanying drawings and examples. It should be understood that the specific examples described herein are only used to explain the present application and are not used to limit the present application. In addition, the technical features involved in each embodiment of the present application described below can be combined with each other as long as they do not conflict with each other.

[0082] Reference Figure 1 The structure of the exemplary air bag support floating raft vibration isolation system of the present application includes six parts of device 1, base 2, air bags (3.1, 3.2, 3.3, 3.4, 3.5, 3.6), displacement sensors (4.1, 4.2, 4.3, 4.4, 4.5, 4.6, 4.7, 4.8), air bag pressure sensors (5.1, 5.2, 5.3, 5.4, 5.5, 5.6), and raft frame 6, wherein the running device 1 is fixed on the raft frame 6, the raft frame 6 is uniformly arranged with six air bag isolators (3.1, 3.2, 3.3, 3.4, 3.5, 3.6) on both sides, the raft frame 6 is supported on the base 2 by the air bags (3.1, 3.2, 3.3, 3.4, 3.5, 3.6), and the base 2 and the surface of the raft frame 6 are not deformed, the system has a total of eight displacement sensors (4.1, 4.2, 4.3, 4.4, 4.5, 4.6, 4.7, 4.8) for detecting the height at each measuring point of the raft frame 6. Each air bag (3.1, 3.2, 3.3, 3.4, 3.5, 3.6) is equipped with a pressure sensor (5.1, 5.2, 5.3, 5.4, 5.5, 5.6) for measuring the actual pressure of the air bag (3.1, 3.2, 3.3, 3.4, 3.5, 3.6), and two high-speed electromagnetic valves are connected with a high-pressure gas source to realize the inflation and exhaust of the air bag (3.1, 3.2, 3.3, 3.4, 3.5, 3.6). The raft frame is divided into four quadrants by the coordinate system, wherein the positions of the first quadrant, the second quadrant, the third quadrant, and the fourth quadrant are 7.1, 7.2, 7.3, and 7.4, respectively.

[0083] The air bag vibration isolation system changes the internal pressure of each air bag by inflating and deflating the air bag, thereby changing the height of the air bag, and effectively controlling the pose of the raft. The air bag is made of elastic material and has a large deformation capacity. By adjusting the air pressure in the air bag, the stiffness and load capacity of the air bag can be changed to adapt to different vibration isolation requirements. When the air bag is inflated, the air pressure in the air bag increases, causing the air bag to expand, which increases the stiffness and load capacity of the air bag. The system gravity remains unchanged, the compression amount of the air bag decreases, and the height of the air bag increases, corresponding to the height of the raft position. Conversely, when deflated, the air pressure in the air bag decreases, the air bag contracts, the stiffness and load capacity decrease, the system gravity remains unchanged, the compression amount of the air bag increases, and the height of the air bag decreases, corresponding to the height of the raft position. By controlling the inflation and deflation of the air bag, the pose of the raft can be accurately adjusted, mainly including the following aspects:

[0084] 1) Height adjustment: Inflating or deflating the air bag can change the height of the air bag, thereby adjusting the height of the raft, and achieving control of the vertical position of the raft.

[0085] 2) Attitude adjustment: Inflating or deflating different air bags can adjust the inclination angle of the raft, and achieve control of the attitude of the raft.

[0086] The control of the air bag support floating raft vibration isolation system in the present application is divided into pose solving and pose control two parts, wherein the pose solving is realized by constructing the pose mathematical model of the system, and the pose control needs to be realized in combination with the results of the pose solving.

[0087] Example 1:

[0088] As Figure 2 shown, a pose adjustment method for an air bag supporting rigid floating raft, comprising the following steps:

[0089] (1) Establishing the air bag supporting floating raft vibration isolation system coordinate system: taking the air bag arrangement direction coinciding with the Y axis in the raft centering state, the raft horizontal plane being perpendicular to the Y axis direction as the X axis, and the coordinate system origin O coinciding with the floating raft gravity center, the air bag supporting floating raft vibration isolation system coordinate system is established;

[0090] With the present embodiment as the research object, the present embodiment has six air bags and eight displacement sensors, three groups are evenly arranged on each side of the raft, the establishment of the system Cartesian coordinate system follows the principle of simplicity and efficiency, so the center of gravity O of the raft is taken as the origin of the coordinate system, in order to more clearly indicate the position of the air bag and the displacement sensor, the arrangement direction of the air bag in the ideal centering state of the raft is taken as coinciding with the Y axis, the direction perpendicular to the Y axis on the plane where the raft is located is taken as the X axis, at this time, the plane where the X and Y axes are located is not necessarily horizontal, it depends on the plane where the raft is located in the ideal centering state, that is, the target pose of the raft is determined under the premise that the air bag adjustment ability is allowed, the Z axis is perpendicular to this plane and the direction is upward, the final establishment result of the system coordinate system is shown in Figure 1 .

[0091] (2) Determine the position parameters of the measuring points: obtain the coordinates of each measuring point on the raft in the system coordinate system of step (1), wherein X and Y depend on the installation position of each displacement sensor, and Z depends on the reading of each displacement sensor;

[0092] After the system coordinate system is established, the reference position of each measuring point on the raft can be obtained from the value of the displacement sensor, that is, the coordinates (X i ,Y i ,z i ), wherein i=1~8, when the raft is in the horizontal centering state, the readings of the eight displacement sensors at this time are recorded, and after calibration, h si is recorded as the reference height of each measuring point on the raft, at this time, the coordinates z i of the i-th measuring point on the raft along the Z axis are all 0, and X i and Y i are the distances of each measuring point along the X axis and the Y axis relative to the center of gravity of the raft, respectively. When the raft deviates from the ideal centering state, the readings of the sensors are calibrated and recorded as h oi , at this time, the coordinates of the i-th measuring point in the system coordinate system along the Z axis are:

[0093] z i =h oi -h si

[0094] If a is the roll angle of the raft, β is the pitch angle of the raft, d is the length of the i-th measuring point from the X axis in the ideal centering state of the raft, d is the length of the i-th measuring point from the Y axis in the ideal centering state of the raft, then after the attitude of the raft changes,

[0095]

[0096] wherein d is the length of the i-th measuring point from the X axis after the attitude of the raft changes, L is the length of the raft from the Y axis after the change of the attitude of the raft. Limited to the adjustable range of the vertical height of the air bag vibration isolator, the maximum misalignment angle of the raft is very small, near 0°, so the cosine values of a and β are approximately 1,

[0097] Therefore

[0098]

[0099] Thus, the air bag coordinate change caused by the change of the attitude angle of the raft is very small, and the influence on the horizontal and vertical coordinates of the measuring points when the attitude of the raft changes is very small. Ultimately, the coordinates of each measuring point in the system coordinate system under any attitude of the raft can be obtained as (X i ,Y i ,z i ), wherein i = 1-8.

[0100] (3) Establishing the plane equation of the raft: using the least square method to fit the coordinates of the measuring points in step (2) to establish the plane equation of the raft;

[0101] The specific steps of step (3) for establishing the plane equation of the raft include:

[0102] (31) The plane equation is established as:

[0103] Z = aX + bY + c

[0104] Wherein a, b, and c are unknown numbers;

[0105] (32) Adding random errors to the plane equation in step (31), then:

[0106] z i = Z i + v i

[0107] or z i = aX i + bY i + c + v i

[0108] In the formula, z i is the measurement data, Z i is the true value, v i is the random error, i represents the number of the measuring point in the system, and i = 1-8;

[0109] (33) Adding each measurement error to obtain the total error, then:

[0110]

[0111] (34) Define the optimization index function J, and use the least square method to perform plane fitting, and find the best function matching of the data by minimizing the sum of squares of errors:

[0112]

[0113] This optimization index function represents the effect of using the least square method to perform plane fitting, and the least square method can find the best function matching of the data by minimizing the sum of squares of errors, and the smaller J is, the better the effect of plane fitting is, that is, when the optimization index function J is the smallest, the corresponding plane equation is the plane equation of the raft to be solved.

[0114] Step (3) establishing the plane equation of the raft also includes:

[0115] (35) converting the plane equation obtained in step (34) into the solving of three unknowns, if J is minimized, use the extreme value method to get:

[0116]

[0117] (36) further arranging the formula in step (35) to get:

[0118]

[0119] (37) converting the formula in step (36) into a matrix form to get:

[0120]

[0121] (38) solving the matrix equation in step (37) to get The obtained plane equation is:

[0122]

[0123] Among them, and indicate the inclination of the raft, the positive and negative of which indicate the size relationship between the actual height of the center of gravity of the raft and the ideal centering height.

[0124] At this point, the position and posture calculation of the air bag supported floating raft vibration isolation system is completed, and after obtaining the mathematical description of the position and posture of the air bag supported floating raft vibration isolation system, the raft position and posture adjustment strategy can be performed.

[0125] (4) analysis of the position and posture calculation result: the plane equation of the raft obtained in step (3) is used to analyze the position and posture calculation result;

[0126] Step (4) analysis of the position and posture calculation result is:

[0127] The system coordinate system according to step (1) divides the plane where the raft is located into four quadrants, and the plane equation obtained in step (3) is combined. As shown in Figure 1 the system coordinate system divides the plane where the raft is located into four quadrants, wherein the air bags 3.1 and 3.2 are located in the first quadrant, the air bag 3.3 is located in the second quadrant, the air bag 3.4 is located in the third quadrant, and the air bags 3.5 and 3.6 are located in the fourth quadrant.

[0128] That is:

[0129] ① If and , then the first quadrant of the raft is the highest, and the corresponding third quadrant is the lowest;

[0130] ② If and , then the second quadrant of the raft is the highest, and the corresponding fourth quadrant is the lowest;

[0131] ③ If and , then the third quadrant of the raft is the highest, and the corresponding first quadrant is the lowest;

[0132] ④ If and , then the fourth quadrant of the raft is the highest, and the corresponding second quadrant is the lowest;

[0133] The positive and negative of the center of gravity of the raft indicate the size relationship between the actual height of the center of gravity and the ideal centering height, if positive, it indicates that the center of gravity of the raft is located above the ideal centering height; otherwise, the center of gravity of the raft is located below the ideal centering height.

[0134] As shown in Figure 2 the air bag supporting the raft vibration isolation system pose control process mainly includes three parts: obtaining the optimal control pressure of the air bag, analyzing the pose solution result, and selecting the air bag and inflation and deflation.

[0135] (5) Obtaining the optimal control pressure of the air bag: regarding the raft adjustment process as a quasi-static process, the torque balance equations of the air bag vibration isolator around the X and Y axes and the force balance equation along the Z axis are obtained from the statics theory, and the optimal control pressure of each air bag is obtained;

[0136] The specific steps of step (5) for obtaining the optimal control pressure of the air bag include:

[0137] (51) Regarding the raft adjustment process as a quasi-static process, the torque balance equations of the air bag vibration isolator around the X and Y axes and the force balance equation along the Z axis are obtained from the statics theory:

[0138]

[0139] where k represents the number of the air bag in the system, and k∈[1, 6], P k is the pressure of the kth air bag, X k , Y k is the coordinate of the kth air bag, S e is the effective area of the air bag, and G is the total weight of the air bag vibration isolation system of the floating raft.

[0140] (52) Increase the air bag pressure uniformity as a constraint condition, and require the pressure variance of each air bag to be minimum, i.e.

[0141]

[0142] (53) Obtain the optimal control pressure P sk of each air bag on the basis of step (52), i.e.

[0143]

[0144] After obtaining the plane equation of the raft and the optimal control pressure of the air bag, the system can be controlled. Since the control is achieved by inflating and deflating the air bag, the selection of the air bag is crucial.

[0145] (6) The pose solution obtained in step (4) and the optimal control pressure of each air bag obtained in step (5) are used to select the air bag and inflate or deflate it. When the pose of the raft reaches the control accuracy, the adjustment is ended; when the pose of the raft does not reach the control accuracy, the pose adjustment is performed again in step (2).

[0146] Define the actual pressure to optimal pressure ratio parameter λ k to select the air bag that needs to be controlled most:

[0147]

[0148] When there are two or more air bags in any quadrant, numbered m1, m2, …, m n :

[0149] ① If and , deflate the air bag m r ;

[0150] ② If and , inflate the air bag m r ;

[0151] where m1, m2, …, m n represent each air bag in the system; n is the total number of air bags in the system, n≥2 and n is an integer; r represents the subscript of the number of the air bag in the system, r∈[1, n] and r is an integer.

[0152] Step (6) selection sequence of airbags and inflation / deflation: follow the selection of quadrant first and then airbag, that is, get the corresponding quadrant from the analysis of a, b, c parameters in step (4) pose solution result, and select the airbag combined with step (5) to obtain the optimal control pressure of airbag, that is:

[0153] When , ① if and deflate the airbag of the first quadrant;

[0154] a. if 3.1 > λ 3.2 , deflate airbag 3.1.

[0155] b. if 3.1 < λ 3.2 , deflate airbag 3.2.

[0156] ② if and deflate airbag 3.3 of the second quadrant;

[0157] ③ if and deflate airbag 3.4 of the third quadrant;

[0158] ④ if and deflate the airbag of the fourth quadrant;

[0159] a. if 3.5 > λ 3.6 , deflate airbag 3.5.

[0160] b. if 3.5 < λ 3.6 , deflate airbag 3.6.

[0161] When , ① if and inflate airbag 3.4 of the third quadrant;

[0162] ② if and inflate the airbag of the fourth quadrant;

[0163] a. if 3.5 > λ 3.6 , inflate airbag 3.6.

[0164] b. if 3.5 < λ 3.6 , inflate airbag 3.5.

[0165] ③ if and Inflating the airbag of the first quadrant;

[0166] a. If λ 3.1 > λ 3.2 , inflate the airbag 3.2.

[0167] b. If λ 3.1 < λ 3.2 , inflate the airbag 3.1.

[0168] IV. If and , inflate the airbag 3.3 of the second quadrant.

[0169] The mathematical description of raft pose solution can not only optimize the adjustment strategy of raft pose, but also bring great convenience to the adjustment strategy of raft pose after system failure.

[0170] Example 2:

[0171] When one or more displacement sensors fail, only the displacement sensor data at the corresponding position needs to be removed, and the remaining displacement sensor data is used to fit a new raft plane equation according to steps (1)-(6) to continue to realize the adjustment of the raft pose.

[0172] Taking the failure of displacement sensors 4.1 and 4.8 as an example, the data of displacement sensors 4.1 and 4.8 need to be removed in the control algorithm, and a new raft plane equation can still be fitted using the data of the remaining 6 displacement sensors.

[0173] New total measurement error:

[0174]

[0175] New optimization index function:

[0176]

[0177] Using the method of extreme value:

[0178]

[0179] Further arrange the above formula:

[0180]

[0181] Written as a matrix as follows:

[0182]

[0183] Solve the above matrix equation, get The new raft plane equation is:

[0184]

[0185] In the worst case, after the displacement sensor fails, it is still used in the fitting of the raft plane equation, and the fitted plane equation is still very close to the real plane equation of the raft. This is because the system is a redundant system, so it has strong anti-interference ability and robustness, and the small change in the value of the individual measuring point has little effect on the overall system fitting of the raft plane equation.

[0186] At the same time, the least squares method used in the raft pose solution has stability and reliability, and the small deviation of individual sensor values will be averaged to all sensors. For noise and small sample data, the least squares method can still provide stable and reliable fitting results, so this situation has little effect on the final raft plane equation. Therefore, the failure of individual displacement sensors has little effect on the system pose solution and pose adjustment. In the case of not requiring high control accuracy, the adjustment strategy is still effective.

[0187] Embodiment 3:

[0188] When one or more airbags fail to inflate and deflate, the pose adjustment strategy can still use the remaining non-failed airbags to inflate and deflate to adjust the pose of the raft.

[0189] Only in the pose adjustment strategy, a new set of optimal control pressures excluding the failed airbag is recalculated, and the optimal control pressures obtained are applied to the control algorithm, so that the adjustment strategy after system failure can be obtained.

[0190] Taking airbag No. 3.6 as an example, airbag No. 3.6 is excluded in the pose adjustment strategy, and the torque balance equations of the air spring isolator around the X and Y axes and the force balance equation along the Z axis become:

[0191]

[0192] From the constraint condition of airbag pressure uniformity, the pressure variance of each airbag is minimized, that is:

[0193]

[0194] Thus, the new optimal control pressure of each airbag is obtained:

[0195]

[0196] As long as P s ' k has a solution, it means that the system still has the potential to maintain stability. In the control algorithm, the above P sk Replace the original P sk And exclude the failure of the air bag, raft still can be adjusted to the ideal pose.

[0197] It can be seen that the control strategy can tap the maximum control potential of the system when the air bag is faulty, and the optimal control pressure has a solution, which means that the system has the ability to adjust the raft to the ideal pose when the air bag is faulty. The calculation of the optimal control pressure of the air bag provides theoretical support for the system to handle air bag failure problems. The detection of the system for the raft pose is not affected, and the raft can still converge to the ideal pose, and the accuracy of the system can be guaranteed.

[0198] Those skilled in the art will readily understand that the above description is only a preferred embodiment of the present application and is not intended to limit the present application, and any modifications, equivalent replacements and improvements made within the spirit and principles of the present application shall be included in the protection scope of the present application.​

Claims

1. A method of adjusting the position of a rigid raft supported by air bags, characterized in that, The method comprises the following steps: (1) Establish the coordinate system of the air bag supporting the raft isolation system: take the raft frame centering state air bag arrangement direction and axis coincides, raft frame horizontal plane and axis vertical direction as axis, the coordinate system origin and the raft center of gravity coincides, the air bag supporting the raft isolation system coordinate system is established; (2) determining the position parameters of the measuring points: obtaining the coordinates of each measuring point on the raft in the system coordinate system of step (1), wherein and depending on the position of the installation of each displacement sensor, depending on the reading of each displacement sensor; (3) establishing a plane equation of the raft: using the least square method to fit the coordinates of the measuring points in step (2) to establish a plane equation of the raft; The specific steps of establishing the plane equation of the raft include: (31) the plane equation is established as: wherein are unknowns; (32) adding random errors in the plane equation in step (31), then: or wherein is the measured data, is the true value, is the random error, denotes the number of the measuring point in the system, and ; (33) adding each measurement error to obtain the total error, then: (34) defining an optimization index function A plane fit is performed using least squares, finding the best function match to the data by minimizing the sum of the squares of the errors: The smaller, the better the effect of the plane fitting, i.e. when the optimization index function The plane equation corresponding to the minimum is the plane equation of the raft to be solved. (4) analysis of the pose solution result: analyzing the pose solution result of the raft according to the plane equation of the raft obtained in step (3); (5) Obtaining the optimal control pressure of the air bags: The adjusting process of the raft is regarded as a quasi-static process. The torque balance equation and the force balance equation of the air bag isolators along the x and y axes are obtained from the statics theory, and the optimal control pressure of each air bag is obtained. 、 ​​ (6) selecting the air bags and the inflation and deflation according to the pose solution result obtained in step (4) and the optimal control pressure of each air bag obtained in step (5), when the pose of the raft reaches the control precision, the adjustment is ended; when the pose of the raft does not reach the control precision, returning to step (2) to re-adjust the pose.

2. The method of adjusting the position of an airbag-supported rigid pontoon according to claim 1, characterized in that, Step (3) of establishing the plane equation of the raft further includes: (35) The obtaining of the plane equation in step (34) is converted into the obtaining of three unknowns, if the minimum is made, and the extreme value method is used to obtain: ​​ (36) further arranging the formula in step (35) to obtain: (37) converting the formula in step (36) into a matrix form to obtain: (38) Solve the matrix equation in step (37) to get , , The equation of the plane sought is obtained as wherein, with represents the inclination of the raft, the positive or negative of which indicates the magnitude relationship between the actual height of the center of gravity of the raft and the ideal height of the centering.

3. The method of adjusting the position of an airbag-supported rigid pontoon according to claim 2, characterized in that, Step (4) of analyzing the pose solution result is: According to the system coordinate system in step (1), the plane where the raft is located is divided into four quadrants, and the plane equation obtained in step (38) is combined to obtain: If and , the raft frame first quadrant is the highest, and the corresponding third quadrant is the lowest. If and then the raft second quadrant is the highest height, the corresponding fourth quadrant height is the lowest; If and then the raft third quadrant height is the highest, and the corresponding first quadrant height is the lowest; If and then the raft frame fourth quadrant height is the highest, and the corresponding second quadrant height is the lowest; If positive, it indicates that the raft center of gravity is above the ideal trim height; otherwise, it indicates that the raft center of gravity is below the ideal trim height.

4. The method of adjusting the position of an airbag-supported rigid raft according to claim 3, characterized by, Step (5) of obtaining the optimal control pressure of the air bag includes the following specific steps: (51) The raft adjustment process is regarded as a quasi-static process, and the moment balance equation of the air bag vibration isolator around the 、 axis and the force balance equation along the axis are obtained from the statics theory. wherein, represents the number of the air cell in the system, and , is the pressure of the th air cell, , is the coordinate of the th air cell, is the effective area of the air cell, is the total weight of the floating raft air cell vibration isolation system; (52) increasing the uniformity of the air bag pressure as a constraint condition, requiring that the variance of the pressure of each air bag is minimized, that is: (53) obtaining the optimal control pressure of each airbag on the basis of step (52) i.e.: 。 5. The method of adjusting the position of an airbag-supported rigid raft according to claim 4, wherein Step (6) selection sequence of air bag and inflation: follow the selection of quadrant first, then select air bag, that is, from the analysis of the results of step (4) pose solution Three parameters corresponding to the quadrant, combined with step (5) to obtain the optimal control pressure of air bag selection air bag, that is: When , ① if and , the airbag in the first quadrant is deflated; If and deflate the airbag of the second quadrant; ③ if and deflate the airbag of the third quadrant; (4) if and deflate the airbag of the fourth quadrant; When , ① if and , the airbag in the third quadrant is inflated; If and inflating the airbag of the fourth quadrant; ③ if and inflating the airbag of the first quadrant; If and Inflate the airbag in the second quadrant.

6. The method of adjusting the position of an airbag-supported rigid raft according to claim 5, wherein Defining actual pressure to optimal pressure ratio parameter to select the airbag that needs control the most: When there are two or more airbags in any quadrant, numbered when: If , and , then deflate the airbag . If , and , then inflate the airbag . wherein represents each airbag in the system; is the total number of airbags in the system, and is an integer; represents an index of the airbag number in the system, and is an integer.

7. The method of adjusting the position of an airbag-supported rigid pontoon according to any one of claims 1 to 6, characterized in that, When one or more displacement sensors fail, the displacement sensor data at the corresponding position is removed, the data of the remaining displacement sensors is used to fit a new plane equation of the raft according to steps (1)-(6), and the adjustment of the pose of the raft is continued.

8. The method of adjusting the position of an airbag-supported rigid pontoon according to any one of claims 1 to 6, characterized in that, When one or more air bags fail to inflate and deflate, the remaining air bags that do not fail to inflate and deflate are used to adjust the pose of the raft.

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