Shafting collaborative centering control method for multi-airbag vibration isolation system

Abstract

The invention discloses a shafting collaborative centering control method for a multi-airbag vibration isolation system, and the method comprises the steps: carrying out the initialization, obtaining the airbag pressure and control target information of N airbag vibration isolators at the current moment t, and calculating the absolute centering amount at the current moment t; the absolute centering amount of a target air bag vibration isolation system needing to be cooperatively centered with the air bag vibration isolation system at the current moment t is obtained, and the relative centering amount of the air bag vibration isolation system relative to the target air bag vibration isolation system is calculated; according to the collaborative centering control method, the absolute centering amount and the relative centering amount are considered at the same time, and the problem that the control track is uncontrollable in independent centering control is solved. The correlation coefficient is adopted to describe the correlation between the control object and the control target, so that the problem of inaccurate modeling of a complex model is avoided.

Description

Technical Field

[0001] The present invention relates to the field of industrial control technology, and in particular to a shaft system coordinated centering control method for a multi-airbag vibration isolation system. Background Art

[0002] The alignment of ship shafting is related to the safe operation of the ship. On the one hand, the misalignment of ship shafting may cause mechanical failures such as bearing damage. On the other hand, the misalignment of shafting will generate additional mechanical noise. The current research on shafting alignment is mainly focused on the design and installation stages. By determining the position of the ship's mechanical bearings and considering factors such as bearing load and hull deformation, the reliable operation of the shafting is ensured. As ships have higher and higher requirements for mechanical noise control, the airbag vibration isolation system has been widely used in the ship field due to its efficient mechanical noise reduction and vibration isolation performance. It is widely used for mechanical vibration isolation of ship main engines and shafting equipment. In particular, when the shafting is misaligned due to the tilting, swaying of the ship and changes in the operating conditions of the equipment, the airbag vibration isolation system can assist in completing the shafting alignment control by actively adjusting the airbag pressure and changing the height of the airbag isolator.

[0003] The ship shafting may be supported by multiple airbag vibration isolation systems, and multiple airbag vibration isolation systems need to work together to complete the centering control. In engineering practice, the shafting centering amount is usually expressed by four components, namely horizontal offset, vertical offset, horizontal deflection and vertical deflection. And when the offset is less than 0.5mm and the deflection is less than 0.5mm / m, the shafting is considered to be in the centering state. However, the current research on the centering control method for airbag vibration isolation system is mainly based on the absolute centering amount for centering control. That is, each airbag vibration isolation system works independently, and each system is set with an ideal centering target. During the centering control process, only the centering offset / deflection of its own shafting system needs to be considered, and the relative centering amount is rarely considered. This method will cause many problems: On the one hand, independent centering control only considers the absolute centering amount, which may cause the shafting to be unable to be centered. For example, the horizontal offset of one airbag vibration isolation system when the centering control is completed is +0.4mm, and the horizontal offset of another airbag vibration isolation system when the centering control is completed is -0.4mm. Both systems believe that they are in the centered state, but the actual relative horizontal offset of the entire shaft system is 0.8mm, which is not in the centered state. On the other hand, the control trajectory of independent centering control is uncontrollable, and misalignment may occur during the control process. For example, when the shaft system itself is in the centered state, but deviates from the absolute centering amount. If the relative centering amount is not considered, the shaft system may be misaligned during the shaft system centering control process due to the lack of collaborative control constraints. Summary of the invention

[0004] In order to overcome the above technical defects, the present invention provides a shaft system collaborative alignment control method for a multi-airbag vibration isolation system, which takes into account both relative alignment and absolute alignment, does not require the establishment of a complex mechanism model, and can adaptively achieve collaborative alignment control.

[0005] The present invention provides a shaft system coordinated centering control method for a multi-airbag vibration isolation system, wherein the airbag vibration isolation system includes N airbag vibration isolators, each of which is inflated and deflated by controlling a solenoid valve; the coordinated centering control method is as follows:

[0006] S0) Initialization, set the upper limit of the safe working pressure value P of each airbag isolator l and the lower limit P u , determine the control target Γ and the optimal control target Γ of the airbag isolator opt , initialize the data set D to an empty set;

[0007] The control target Γ includes M control targets, which can be expressed as:

[0008] Γ={τ1,…,τ M};

[0009] Optimal control objective Γ opt Expressed as: opt ={τ1 opt ,…,τ M opt};

[0010] The upper and lower limits of the pressure value are P l = {p1 l ,…,p N l}、P u = {p1 u ,…,p N u};

[0011] S1) Obtain the airbag pressure P(t) of N airbag isolators at the current time t = {p1,…,p N} and control target information Γ(t)={τ1,…,τ M}, and calculate the absolute centering value at the current time t; add the airbag pressure and the absolute centering value to the data set D, and update the correlation coefficient matrix R;

[0012] S2) obtaining the absolute centering amount of the target airbag vibration isolation system that needs to be coordinated with the airbag vibration isolation system at the current time t, and calculating the relative centering amount of the airbag vibration isolation system relative to the target airbag vibration isolation system; if the absolute centering amount of the target airbag vibration isolation system cannot be obtained, jump to step S3, otherwise jump to step S4;

[0013] S3) The relative centering value is the same as the absolute centering value of the airbag vibration isolation system, that is,

[0014]

[0015] S4) If the absolute centering amount and the relative centering amount of the airbag vibration isolation system at the current time t both meet the centering requirements, jump to step S1; if the absolute centering amount and the relative centering amount of the airbag vibration isolation system at the current time t meet the coordinated centering control, jump to step S5; if the absolute centering amount and the relative centering amount of the airbag vibration isolation system at the current time t only meet the independent centering control, jump to step S3;

[0016] S5) Collaborative centering control conditions: select the control target to be controlled according to the absolute centering value and relative centering value of the airbag vibration isolation system at the current time t, select the number of the airbag vibration isolator to be controlled according to the correlation coefficient, and after executing the control action, jump to step S1 to perform collaborative centering control at the next moment.

[0017] Furthermore, in step S1), the absolute centering value ΔΓ a The calculation formula is as follows:

[0018]

[0019] Furthermore, in step S1), the correlation coefficient is expressed as:

[0020] R = {r ij |1≤i≤N,1≤j≤M}

[0021] Among them, r ij represents the correlation between the pressure of the i-th airbag isolator and the j-th control target;

[0022] If the data set D = {(P1,Γ1),…,(P K ,Γ K The number of data entries K in )} is less than the set threshold K T , then set the correlation coefficient to r ij =1;

[0023] Otherwise, when K ≥ K T The function formula for calculating the correlation coefficient is:

[0024]

[0025] in, Denotes the data set D = {(P1,Γ1),…,(P K ,Γ K )}, the i-th airbag isolator pressure value in the k-th data, represents the average value of the pressure of the ith airbag isolator in the data set; represents the jth control target component in the kth data in the data set D, Represents the average value of the jth control target of the data set.

[0026] Furthermore, in the step S2), the absolute centering value ΔΓ′ of the target airbag vibration isolation system that needs to be coordinated with the airbag vibration isolation system at the current time t is obtained: Δτ1′={Δτ1′,…,Δτ M '}, the relative centering value is calculated by the following formula:

[0027]

[0028] Furthermore, in the step S4), the standard that the absolute centering amount and the relative centering amount of the airbag vibration isolation system at the current time t both meet the centering requirement is that each centering amount is less than a set error, that is:

[0029]

[0030] where ξ j Is a constant.

[0031] Furthermore, in the step S4), the absolute centering value and the relative centering value of the airbag vibration isolation system at the current time t satisfy the condition of coordinated centering control if there is a relative centering value component greater than a set error:

[0032]

[0033] Furthermore, in the step S4), the absolute centering amount and the relative centering amount of the airbag vibration isolation system at the current time t satisfy the condition of independent centering control, and all relative centering components are less than the set error:

[0034]

[0035] Furthermore, the specific process of step S5) is as follows:

[0036] S51) Select the control target with the largest absolute value of relative centering deviation, denoted as Where m represents the sequence number in the set;

[0037] S52) Develop control strategy: If and The inflation action is performed first, and the process goes to step S53; if and The deflation action is performed first, and the process goes to step S54; otherwise, no action is performed, and the process goes to step S1;

[0038] S53) Calculate the auxiliary inflation decision value, recorded as The calculation method is as follows:

[0039]

[0040] if If all the elements in are not zero, the probability distribution of auxiliary inflation decision is calculated. The calculation method is as follows:

[0041]

[0042] if If all the elements in are zero, jump to S1;

[0043] according to The probability distribution value of selects the number of the airbag isolator that needs to be inflated. Assuming that the selected airbag isolator is No. i, the airbag isolator is inflated with Δp; Δp is a preset fixed value;

[0044] S54) Calculate the auxiliary deflation decision value, recorded as The calculation method is as follows:

[0045]

[0046] if If all the elements in are not zero, then the auxiliary deflation decision probability distribution is calculated The calculation method is as follows:

[0047]

[0048] if If all the elements in are zero, jump to step S1;

[0049] according to The probability distribution value of is used to select the number of the airbag isolator that needs to be deflated. Assuming that the airbag isolator No. i is selected, the airbag isolator is deflated by Δp, where Δp is a preset fixed value.

[0050] The collaborative centering control method proposed in the present invention considers both the absolute centering amount and the relative centering amount, solving the problem of uncontrollable control trajectory in independent centering control. The correlation coefficient is used to describe the relationship between the control object and the control target, avoiding the problem of inaccurate modeling of complex models.

[0051] Compared with the prior art, the present invention has the following technical effects:

[0052] 1) The shaft system coordinated centering method provided by the present invention considers both the absolute centering amount and the relative centering amount, which can ensure accurate centering during and after the shaft system centering control process;

[0053] 2) The correlation coefficient used in the present invention is updated in real time through the collected system operation data, and does not require the establishment of a complex mathematical model or manual intervention, and has a high degree of intelligence;

[0054] 3) The control method provided by the present invention has a simple structure, small amount of calculation, easy implementation and deployment, and good control effect. BRIEF DESCRIPTION OF THE DRAWINGS

[0055] Figure 1 This is a typical schematic diagram of the coordinated alignment of the shafting of a multi-airbag vibration isolation system;

[0056] Figure 2 It is a schematic flow chart of the control method of the present invention;

[0057] Figure 3 It is a training curve diagram of the active shaft alignment control effect in the simulation environment of the present invention ((a) is the absolute alignment amount, (b) is the relative alignment amount);

[0058] Figure 4 It is a training curve diagram of the passive shaft alignment control effect in a simulation environment of the present invention ((a) is the absolute alignment amount, (b) is the relative alignment amount). DETAILED DESCRIPTION

[0059] In order to make the purpose, technical solution and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0060] like Figure 1 As shown in the figure, the propulsion system shafting equipment is supported by two airbag vibration isolation systems, one of which supports the motor equipment and outputs power, which is called the propulsion motor airbag vibration isolation system; the other airbag vibration isolation system supports the bearing and other equipment, which is the stern airbag vibration isolation system. For the sake of distinction, the shaft connected to the motor is called the active shaft, and the shaft connected to it through a coupling is called the passive shaft. After the static alignment is completed, the entire propulsion shafting has an optimal control target, and the deviation value from the optimal control target in each airbag vibration isolation system is the absolute alignment value. Each airbag vibration isolation system usually includes a set of airbag vibration isolators and a control system. The airbag vibration isolator can directly or indirectly support the bearing equipment through the raft. The control system can collect the alignment status of the shafting equipment and formulate a control strategy, and finally hand it over to the control module to execute the control action. For example, the inflation / deflation action of the airbag vibration isolator is completed through the inflation / deflation control unit to achieve the attitude control of the raft, and then adjust the alignment status of the shafting equipment.

[0061] The collaborative centering control method for a multi-airbag vibration isolation system provided by the present invention is as follows: Figure 2 As shown, the following steps are included:

[0062] S0) is initialized. Assume that the propulsion motor airbag vibration isolation system includes 8 airbag vibration isolators, each of which can be inflated and deflated by controlling the solenoid valve. Then the combination of airbag pressure values ​​is expressed as P = (p1, ..., p8), p i represents the pressure value of airbag isolator i (1≤i≤8); for the safe working pressure of the airbag, a safety constraint is set. Assuming that the upper and lower limits of the pressure values ​​of all airbag isolators are the same, 2.0 MPa and 0.8 MPa respectively, the safety constraint can be expressed as P l ={ 1n p l ,.·,p l , P u = {p1 u ,…,p n u}={2.0Mpa,…,2.0Mpa}. Determine the control target Γ and the optimal control target Γ opt Taking the axis alignment control as an example, the control target is generally four components: vertical offset τ1, horizontal offset τ2, vertical skew τ3 and horizontal skew τ4, expressed as: Γ = {τ1, τ2, τ3, τ4}, the optimal control target offset value and skew value are both 0, that is: Γ opt ={0,0,0,0}. Initialize the data set D to an empty set

[0063] S1) Data acquisition: Obtain the airbag pressure P(t) = {p1, ..., p8} and control target information Γ(t) = {τ1, ..., τ4} of the eight airbag isolators at the current time t, and calculate the absolute centering value of the current system:

[0064]

[0065] The collected data is added to the data set D, and the correlation coefficient matrix R is updated. There are 8 airbags and 4 centering state components in the system, so the correlation between the airbag pressure and the 4 centering states is calculated, and the correlation coefficient is expressed as:

[0066] R = {r ij |1≤i≤8,1≤j≤4}

[0067] Among them, r ij Represents the correlation between the pressure of the i-th airbag and the j-th control target component.

[0068] If the data set D = {(P1,Γ1),…,(P K ,Γ K The number of data entries K in )} is less than the set threshold K T , then set the correlation coefficient to r ij=1.

[0069] Otherwise, when K ≥ K T The function formula for calculating the correlation coefficient is:

[0070]

[0071] in, Denotes the data set D = {(P1,Γ1),…,(P K ,Γ K )}, the i-th airbag pressure value in the k-th data, Represents the average value of the i-th airbag pressure in the data set. represents the jth control target component in the kth data in the data set D, Represents the average value of the jth control target component of the data set. In a typical airbag vibration isolation system prototype, the updated correlation matrix is:

[0072]

[0073] Among them, r 11 =-0.12 indicates that there is a negative correlation between the pressure of airbag No. 1 and the vertical deviation, and the correlation value is 0.12.

[0074] S2) Obtain the absolute centering value of the target airbag vibration isolation system that needs to be coordinated with the airbag vibration isolation system at the current time t. If the relative centering value cannot be obtained, jump to step S3; otherwise, jump to step S4.

[0075] Assume that the absolute centering value of the driving shaft of the propulsion motor airbag vibration isolation system is:

[0076] ΔΓ a ={1.6,-2.93,0.1,1.83}

[0077] The absolute centering value of the passive axis of the stern airbag vibration isolation system that needs to be coordinated is:

[0078] ΔΓ'={1.32,-2.96,0.08,1.84}

[0079] At this time, the relative centering amount is:

[0080] ΔΓ r =ΔΓ a -ΔΓ'={0.28,0.03,0.02,-0.01}

[0081] Jump to step S4.

[0082] S3) Set the relative centering value to be the same as the absolute centering value, that is

[0083]

[0084] S4) If the absolute centering value and the relative centering value of the airbag vibration isolation system at the current moment t both meet the centering requirements, jump to step S1; if the absolute centering value and the relative centering value of the airbag vibration isolation system at the current moment t meet the coordinated centering control, jump to step S5; if the absolute centering value and the relative centering value of the airbag vibration isolation system at the current moment t only meet the independent centering control, jump to step S3.

[0085] The standard for the absolute and relative alignment to meet the alignment requirements is that each alignment is less than the set error, that is:

[0086]

[0087] The condition for cooperative centering control is that there is a relative centering component that is greater than the set error:

[0088]

[0089] The independent centering control condition is that all relative centering components are less than the set error:

[0090]

[0091] In engineering, when the offset is less than 0.5 mm and the deflection is less than 0.5 mm / m, the shaft system is considered to be in the centered state. Therefore, ξ j =0.5,1≤j≤4.

[0092] Considering that the absolute and relative centering values ​​are: ΔΓ a ={1.6,-2.93,0.1,1.83} and ΔΓ r ={0.28, 0.03, 0.02, -0.01}, which meets the conditions for coordinated centering control. Jump to step S5.

[0093] S5) Collaborative centering control conditions: select the control target to be controlled according to the values ​​of absolute centering amount and relative centering amount, select the number of the airbag isolator to be controlled according to the correlation coefficient, and after executing the control action, jump to step S1 to perform collaborative centering control at the next moment.

[0094] The specific process of collaborative centering control is as follows:

[0095] S51) Select the control target with the largest absolute value of relative centering deviation, denoted as Where m represents the sequence number in the set.

[0096] Here the relative centering value ΔΓ r ={0.28,0.03,0.02,-0.01}, so

[0097]

[0098] S52) Develop control strategy: If and The inflation action is performed first, and the process goes to step S53; if and The deflation action is performed first and the process goes to step S54; otherwise, no action is performed and the process goes to step S1.

[0099] Since m = 1, and Therefore, the deflation action is performed first and the process jumps to step S54.

[0100] S53) Calculate the auxiliary inflation decision value, recorded as The calculation method is as follows:

[0101]

[0102] if If all the elements in are not zero, the probability distribution of auxiliary inflation decision is calculated. The calculation method is as follows:

[0103]

[0104] if If all elements in are zero, jump to S1.

[0105] according to The probability distribution value of selects the number of the airbag isolator to be inflated. Assuming that the selected airbag isolator is number i, the airbag isolator is inflated by Δp; Δp is a preset fixed value. After the inflation action is executed, jump to step S1.

[0106] S54) Calculate the auxiliary deflation decision value, recorded as The calculation method is as follows:

[0107]

[0108] if If all the elements in are not zero, then the auxiliary deflation decision probability distribution is calculated The calculation method is as follows:

[0109]

[0110] if If all the elements in are zero, jump to step S1.

[0111] according to The probability distribution value of selects the number of the airbag isolator to be deflated. Assuming that the selected airbag isolator is No. i, the airbag isolator is deflated by Δp, where Δp is a preset fixed value. After the deflation action is performed, jump to step S1.

[0112] Assuming the pressure value at this time is: P(t) = {1.0, 1.0, 1.0, 1.0, 1.1, 1.0, 1.2, 1.1}, the auxiliary deflation decision value can be obtained:

[0113] because The elements in are not all zero, and the probability distribution of auxiliary deflation decision can be calculated: That is, there is a 6% chance of selecting airbag vibration isolator No. 4, a 76% chance of selecting airbag vibration isolator No. 6, and an 18% chance of selecting airbag vibration isolator No. 8. Assuming that airbag vibration isolator No. 6 is selected, deflation control is performed on airbag vibration isolator No. 6, and the deflation size is Δp = 0.1Mpa. After the deflation action is performed, jump to step S1.

[0114] like Figure 3 , 4 The implementation results shown are the control process of the airbag vibration isolation system alignment control using the shaft system coordinated control method. Assuming that both the active shaft and the passive shaft are not at the optimal control target at the beginning, the control program is executed once per second. It can be seen that: 1) in about 50 seconds, the controller can quickly achieve alignment control from the shaft system misalignment state and achieve the control target, and the control effect is relatively stable; 2) during the control process, the relative alignment amount can be stabilized within the allowable error range (±0.5mm or ±0.5mm / m).

Claims

1. A method for controlling the coordinated centering of a shaft system for a multi-airbag vibration isolation system, wherein the airbag vibration isolation system comprises N airbag vibration isolators, each of which is inflated and deflated by controlling a solenoid valve; the method is characterized in that: The collaborative centering control method is as follows: S0) Initialization, set the upper limit of the safe working pressure value P of each airbag isolator l and the lower limit P u , determine the control target Γ and the optimal control target Γ of the airbag isolator opt , initialize the data set D to an empty set; The control target Γ includes M control targets, which can be expressed as: C={τ1,…,τ M }; Optimal control objective Γ opt Expressed as: opt ={τ1 opt ,…,τ M opt }; The upper and lower limits of the pressure value are P l = {p1 l ,…,p N l }、P u = {p1 u ,…,p N u }; S1) Obtain the airbag pressure P(t) of N airbag isolators at the current time t = {p1,…,p N } and control target information Γ(t)={τ1,…,τ M }, and calculate the absolute centering value at the current time t; add the airbag pressure and the absolute centering value to the data set D, and update the correlation coefficient matrix R; S2) obtaining the absolute centering amount of the target airbag vibration isolation system that needs to be coordinated with the airbag vibration isolation system at the current time t, and calculating the relative centering amount of the airbag vibration isolation system relative to the target airbag vibration isolation system; if the absolute centering amount of the target airbag vibration isolation system cannot be obtained, jump to step S3, otherwise jump to step S4; S3) The relative centering value is the same as the absolute centering value of the airbag vibration isolation system, that is, S4) If the absolute centering value and the relative centering value of the airbag vibration isolation system at the current time t both meet the centering requirements, jump to step S1; if the absolute centering value and the relative centering value of the airbag vibration isolation system at the current time t meet the coordinated centering control, jump to step S5; If the absolute centering value and the relative centering value of the airbag vibration isolation system at the current time t only meet the independent centering control, jump to step S3; S5) Collaborative centering control conditions: select the control target to be controlled according to the absolute centering value and relative centering value of the airbag vibration isolation system at the current time t, select the number of the airbag vibration isolator to be controlled according to the correlation coefficient, and after executing the control action, jump to step S1 to perform collaborative centering control at the next moment.

2. The method for coordinated axis alignment control of a multi-airbag vibration isolation system according to claim 1 is characterized in that: In the step S1), the absolute centering value ΔΓ a The calculation formula is as follows:

3. The shaft system coordinated alignment control method for a multi-airbag vibration isolation system according to claim 1 is characterized in that: In the step S1), the correlation coefficient is expressed as: R={r ij |1≤i≤N,1≤j≤M} Among them, r ij represents the correlation between the pressure of the i-th airbag isolator and the j-th control target; If the data set D = {(P1,Γ1),…,(P K ,Γ K The number of data entries K in )} is less than the set threshold K T , then set the correlation coefficient to r ij =1; Otherwise, when K ≥ K T The function formula for calculating the correlation coefficient is: in, Denotes the data set D = {(P1,Γ1),…,(P K ,Γ K )}, the i-th airbag isolator pressure value in the k-th data, represents the average value of the pressure of the ith airbag isolator in the data set; represents the jth control target component in the kth data in the data set D, Represents the average value of the jth control target of the data set.

4. The shaft system coordinated alignment control method for a multi-airbag vibration isolation system according to claim 1 is characterized in that: In the step S2), the absolute centering value ΔΓ′ of the target airbag vibration isolation system that needs to be coordinated with the airbag vibration isolation system at the current time t is obtained. M '}, the relative centering value is calculated by the following formula:

5. The shaft system coordinated alignment control method for a multi-airbag vibration isolation system according to claim 1, characterized in that: In the step S4), the standard that the absolute centering amount and the relative centering amount of the airbag vibration isolation system at the current time t both meet the centering requirement is that each centering amount is less than the set error, that is: where ξ j Is a constant.

6. The method for coordinated shaft alignment control of a multi-airbag vibration isolation system according to claim 1, characterized in that: In the step S4), the absolute centering value and the relative centering value of the airbag vibration isolation system at the current time t satisfy the condition of coordinated centering control if there is a relative centering value component greater than the set error:

7. The shaft system coordinated alignment control method for a multi-airbag vibration isolation system according to claim 1, characterized in that: In step S4), the absolute centering amount and relative centering amount of the airbag vibration isolation system at the current time t satisfy the condition of independent centering control, and all relative centering components are less than the set error:

8. The method for controlling the coordinated centering of shafts for a multi-airbag vibration isolation system according to claim 1, characterized in that: The specific process of step S5) is as follows: S51) Select the control target with the largest absolute value of relative centering deviation, denoted as Where m represents the sequence number in the set; S52) Develop control strategy: If and The inflation action is performed first, and the process goes to step S53; if and The deflation action is performed first, and the process goes to step S54; otherwise, no action is performed, and the process goes to step S1; S53) Calculate the auxiliary inflation decision value, recorded as The calculation method is as follows: if If all the elements in are not zero, the probability distribution of auxiliary inflation decision is calculated. The calculation method is as follows: if If all the elements in are zero, jump to S1; according to The probability distribution value of selects the number of the airbag isolator that needs to be inflated. Assuming that the selected airbag isolator is No. i, the airbag isolator is inflated with Δp; Δp is a preset fixed value; S54) Calculate the auxiliary deflation decision value, recorded as The calculation method is as follows: if If all the elements in are not zero, then the probability distribution of auxiliary deflation decision is calculated The calculation method is as follows: if If all the elements in are zero, jump to step S1; according to The probability distribution value of is used to select the number of the airbag isolator that needs to be deflated. Assuming that the airbag isolator No. i is selected, the airbag isolator is deflated by Δp, where Δp is a preset fixed value.

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