Multi-jack synchronous lifting control method for numerical control hydraulic jacks

Abstract

The invention provides a multi-jack synchronous lifting control method of a numerical control hydraulic jack. The method comprises the following steps: calculating through a plurality of groups of lifting experiments to obtain a function relational expression group of the lifting speed of each stage of hydraulic cylinder of each jack and the analog quantity signal numerical value of a proportional electromagnetic valve; one of the roofs is set as an active roof, the other roofs are set as following roofs, and synchronous ascending or synchronous descending is started; determining the hydraulic cylinder stage number according to the actual height of each roof in real time so as to determine and call the function relation between the lifting speed of the hydraulic cylinder with the corresponding stage number and the analog quantity signal value of the proportional electromagnetic valve to control the output of the analog quantity signal value of the proportional electromagnetic valve; the displacement error between the following roof and the active roof is monitored in real time, and the speed of the following roof is corrected according to the displacement error; and when it is detected that the lifting height is reached, the synchronous lifting program is ended. According to the method, it can be guaranteed that the multiple hydraulic cylinders have high synchronous movement precision and positioning precision, transverse extension can be achieved, the multiple hydraulic cylinders are controlled to operate synchronously at high precision, and the method can be applied to many occasions.

Description

Technical Field

[0001] The present invention relates to the technical field of automatic control, and particularly to a synchronous lifting control method for a numerically controlled hydraulic jack with multiple jacks. Background Art

[0002] During the overall assembly stage and maintenance process of an aircraft, it is necessary to lift the entire aircraft to facilitate the installation of landing gears and other components, as well as maintenance work. Generally, an aircraft is equipped with 3 jacks, one nose jack and two wing jacks. Since the previously equipped jacks were hydraulic manual types, the lifting and lowering of the jacks were operated by manual hand cranking, which was laborious and time-consuming. At the same time, due to certain requirements for the synchronization of each jack during the lifting and lowering of the aircraft, too poor synchronization would lead to the risk of the aircraft falling off the jacks, and the manually operated hydraulic jacks could not guarantee the synchronous lifting and lowering requirements of the aircraft.

[0003] Therefore, in view of the deficiencies of traditional manually operated hydraulic jacks, a new numerically controlled hydraulic jack is developed, using a digital automatic control and adjustment method to achieve the precise synchronous lifting and lowering function of the jacks, improving the work efficiency and use safety on site. Summary of the Invention

[0004] The present invention provides a synchronous lifting control method for a numerically controlled hydraulic jack with multiple jacks. The control method provided by the present invention can ensure that the entire set of jack control systems has a very high synchronous lifting control accuracy, and at the same time has functions of speed control and stroke control, with perfect safety protection, and can well meet the on-site requirements.

[0005] The technical solution of the present invention is: In order to achieve the above-mentioned invention purpose, a synchronous lifting control method for a numerically controlled hydraulic jack with multiple jacks is proposed. The system includes a set of control systems that simultaneously control the lifting and lowering of n (n>3) jacks. The structure and parameters of each jack are the same, including a servo motor, a hydraulic pump, a proportional solenoid valve for adjusting the lifting direction and speed of the jack, an m (m>3)-stage telescopic hydraulic cylinder, and a wire rope encoder for measuring the height of the jack. Given the cross-sectional areas S1, S2... Sm of each stage of the hydraulic cylinder of the jack, the maximum lifting speed Vmax of the jack, the maximum allowable synchronous error ΔL of 0.5 mm, and the heights L1, L2... Lm of each stage of the hydraulic cylinder, and when the jack rises from the lowest height, the first-stage cylinder extends first, and the m-stage cylinder extends last, and when the jack descends from the highest height, the m-stage cylinder retracts first, and the first-stage cylinder retracts last. This control method is also applicable to the synchronous lifting control of multiple jacks with different structures and parameters, and includes the following steps:

[0006] Step 1: According to the characteristics of the hydraulic pump, the cross-sectional area S1 of the first stage of the hydraulic cylinder, and the maximum lifting speed Vmax, calculate the minimum rotational speed F of the motor, and control the hydraulic pump motor to operate at a constant rotational speed;

[0007] Step 2: Obtain data through multiple sets of lifting and lowering experiments, and calculate a set of functional relationships between the lifting speeds of each hydraulic cylinder of each jack and the analog signal values of the proportional solenoid valves.

[0008] Step 3: Select the synchronous lifting and synchronous lowering programs, input the lifting speed value x and the lifting height H. The control program determines whether x is less than or equal to Vmax. After meeting the condition, call the synchronous lifting program or the synchronous lowering program. The control program sets the 1# jack as the active jack and the other jacks as the follower jacks.

[0009] Step 4: In the synchronous lifting and lowering control program, the control program monitors the displacement error between the follower jack and the active jack, and determines which stage of the hydraulic cylinder is expanding or contracting according to the actual height of each jack, so as to determine which functional relationship between the lifting speed of the hydraulic cylinder and the analog signal value of the proportional solenoid valve should be called to control the output analog signal value of the proportional solenoid valve. At the same time, the control program monitors ∣△L 21 ∣, ∣△L 31 ∣,... ∣△L n1 ∣ is greater than △L? Whether the real-time height of each jack has reached the maximum height (the minimum height is zero)? Has the lifting height been reached?

[0010] Step 5: The control program determines the positive and negative values of the displacement error between the follower jack and the active jack. When it is positive, the control program decelerates the follower jack; when it is negative, the control program accelerates the follower jack, and returns to Step 4 to loop.

[0011] Step 6: When the control program detects that ∣△L 21 ∣, ∣△L 31 ∣,... ∣△L n1 ∣ is greater than △L?, the synchronous lifting and lowering action stops, analyze and find the reason. After troubleshooting, restart the synchronous lifting and lowering, and return to Step 3.

[0012] Step 7: When the control program detects that the lifting height has been reached, or in the synchronous lifting control, the real-time height of any jack reaches the maximum height, and in the synchronous lowering control, the real-time height of any jack reaches the minimum height of zero, the synchronous lifting program ends and each jack stops moving.

[0013] In a possible embodiment, the minimum rotational speed of the motor in Step 1 is obtained through the following formula.

[0014] Q = S1 × Vmax (1)

[0015] F = Q ÷ M = S1 × Vmax ÷ M (2)

[0016] It is set that the hydraulic pump motor runs at 1.1*F rotational speed.

[0017] Where:

[0018] Q is the maximum flow rate value that the hydraulic pump needs to provide, S1 is the cross-sectional area of the top first-stage cylinder, Vmax is the maximum lifting and lowering speed of the jack, and M is the flow coefficient of the hydraulic pump.

[0019] In a possible embodiment, the functional relationship group in step 2 is obtained through the following test:

[0020] From the relationship diagram between the analog value input through the proportional solenoid valve and the solenoid valve opening, it is known that when the analog value changes from 0 to -13824, the solenoid valve opening changes from 0 degrees to -90 degrees, and the hydraulic cylinder pushes the top to descend, and the descending speed gradually changes from slow to fast. When the analog value changes from 0 to 13824, the solenoid valve opening changes from 0 degrees to 90 degrees, and the hydraulic cylinder pushes the top to rise, and the descending speed gradually changes from slow to fast. By outputting analog values to the proportional solenoid valve through tests and measuring and recording the lifting and lowering speed of the top, after conducting multiple groups of tests on each cylinder of each top, the functional relationship group between the lifting and lowering speed x of the hydraulic cylinder and the numerical value Y of the analog signal of the proportional solenoid valve can be obtained:

[0021] For the first-stage cylinder of the 1# top to rise: Y 1 = a 11 x 2 + b 11 X + c 11 (3)

[0022] For the second-stage cylinder of the 1# top to rise: Y 1 = a 12 x 2 + b 12 X + c 12 (4)

[0023] ……

[0024] For the m-stage cylinder of the 1# top to rise: Y 1 = a 1m x 2 + b 1m X + c 1m (5)

[0025] ……

[0026] For the first-stage cylinder of the n# top to rise: Y n = a n1 x 2 + b n1 X + c n1 (6)

[0027] For the second-stage cylinder of the n# top to rise: Y n = a n2 x 2 + b n2 X + c n2 (7)

[0028] ……

[0029] The n# top m-level cylinder rises: Y n = a nm x 2 + b nm X + c nm (8)

[0030] The 1# top first-level cylinder descends: Y 1 = Ax 2 + B 11 X + C 11 (9)

[0031] The 1# top second-level cylinder descends: Y 1 = A 12 x 2 + B 12 X + C 12 (10)

[0032] ……

[0033] The 1# top m-level cylinder descends: Y 1 = A 1m x 2 + B 1m X + C 1m (11)

[0034] ……

[0035] The n# top first-level cylinder descends: Y n = A n1 x 2 + B n1 X + C n1 (12)

[0036] The n# top second-level cylinder descends: Y n = A n2 x 2 + B n2 X + C n2 (13)

[0037] ……

[0038] The n# top m-level cylinder descends: Y n = A nm x 2 + B nm X + C nm (14)

[0039] Wherein:

[0040] Y 1 、Y 2 ……Y nThe analog signal values of the proportional solenoid valves, which are 1# top, 2# top, …… n# top respectively, x is the lifting speed of the top (0 < x ≤ Vmax), and a11, a12, …… a1m, …… an1, an2, …… anm, A11, A12, …… A1m, …… An1, An2, …… Anm are all constants.

[0041] In a possible embodiment, in step 4 for calculating the displacement error and determining the functional relationship, at the moment when the synchronous lifting program starts to run, the control system reads the position values of each top

[0042] L 10 、L 20 ……L n0 Set the values as initial values and save them. At the same time, the control system reads the position values L 1t 、L 2t ……L nt during synchronous lifting, calculates and obtains the displacement values of each top, and the displacement errors between each follower top and the active top are calculated as follows:

[0043] Displacement values of each top during synchronous upward movement:

[0044] △L 1 =L 1t -L 10 (15)

[0045] △L 2 =L 2t -L 20 (16)

[0046] ……

[0047] △L n =L nt -L n0 (17)

[0048] Displacement values of each top during synchronous downward movement:

[0049] △L 1 =L 10 -L 1t (18)

[0050] △L 2 =L 20 -L 2t (19)

[0051] ……

[0052] △L n =L n0 -L nt (20)

[0053] Calculation of displacement error of each follower top and the active top:

[0054] △L 21 =△L 2 -△L 1 (21)

[0055] △L 31 =△L 3 -△L 1 (22)

[0056] ……

[0057] △L n1 =△L n -△L 1 (23)

[0058] The control system determines which hydraulic cylinder is operating by reading the real-time height of each top. When the real-time height of the top meets:

[0059] 0 + L 1 +…L m1-1 <L n1t ≤L 1 +…L m1 {m≥m1≥1,n1∈(1,n)} (24)

[0060] It can be determined that the m1 - level cylinder of the n1 - th top is rising or falling. The system will call the functional relationship as:

[0061] During synchronous upward movement: Y n1 =a n1m1 x 2 +b n1m1 X + c n1m1 (25)

[0062] During synchronous downward movement: Y n1 =A n1m1 x 2 +B n1m1 X + C n1m1 (26)

[0063] Where:

[0064] L 10 、L 20……Ln0 are the initial heights of synchronous lifting and lowering of the 1# top, 2# top... n# top respectively,

[0065] L 1t 、L 2t……Lnt are the real-time heights of synchronous lifting and lowering of the 1# top, 2# top... n# top respectively,

[0066] △L 1 、△L 2 ……△Ln The synchronous lifting displacements of the 1# top, 2# top... n# top are respectively

[0067] △L 21 and △L 31 ... △L n1 The synchronous lifting displacement differences between the 2# top... n# top and the 1# top are respectively

[0068] In a possible embodiment, in step 5, when the 1# top, 2# top... n# top are synchronously rising with the m1-level cylinders respectively, and the control system detects that 0 < △L 21 < △L, it indicates that the speed of the 2# top is faster than that of the 1# top. The control system will reduce the speed of the 2# top and assign it as When the control system detects that -△L < △L 21 < 0, it indicates that the speed of the 2# top is slower than that of the 1# top. The control system will increase the speed of the 2# top and assign it as Therefore, when the 2# top is under synchronous control, the function correction relationship formula between the lifting speed x of the 2# top hydraulic cylinder and the analog signal value Y of the proportional solenoid valve is:

[0069]

[0070] Similarly:

[0071]

[0072] When synchronously descending, the function correction relationship formula between the lifting speed x of the follower top hydraulic cylinder and the analog signal value Y of the proportional solenoid valve is:

[0073]

[0074] In a possible embodiment, in step 7, when the control system detects L during the synchronous lifting process 1t and L 2t……Lnt and the implementation height of any top is greater than or equal to L 1 + L 2 +... L n , and during the synchronous descending process, when it detects that the implementation height of any top in L 1t and L 2t……Lnt is less than or equal to 0, or when the synchronous lifting displacement of any top in △L 1 and △L 2 ... △L n reaches H, the control system will close all proportional solenoid valves, and the lifting actions of all tops will end.

[0075] The beneficial effects of the present invention are as follows: The present invention provides a control method for synchronous lifting of multiple numerically controlled hydraulic jacks. This method can ensure that the multiple jacks have very high synchronous movement accuracy and good positioning accuracy, and the system can be horizontally extended to control the high-precision synchronous operation of multiple hydraulic cylinders, and can be applied in many occasions. Description of the Drawings

[0076] Figure 1 Flowchart of the method of the preferred embodiment of the present invention;

[0077] Figure 2 Relationship diagram between the input analog value of the proportional solenoid valve and the opening of the solenoid valve in the preferred embodiment of the present invention;

[0078] Figure 3 Function relation diagram between the lifting speed of the first-stage cylinder of the No. 1 jack and the numerical value of the analog signal of the proportional solenoid valve in the preferred embodiment of the present invention;

[0079] Figure 4 Function relation diagram between the lifting speed of the first-stage cylinder of the No. 2 jack and the numerical value of the analog signal of the proportional solenoid valve in the preferred embodiment of the present invention;

[0080] Figure 5 Corresponding table between the lifting test speed of the first-stage cylinder of the No. 1 jack and the numerical value of the analog signal of the proportional solenoid valve in the preferred embodiment of the present invention;

[0081] Figure 6 Corresponding table between the lifting test speed of the first-stage cylinder of the No. 2 jack and the numerical value of the analog signal of the proportional solenoid valve in the preferred embodiment of the present invention. Detailed Embodiment

[0082] To make the objectives, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are some but not all of the embodiments of the present invention. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0083] The features and exemplary embodiments of various aspects of the present invention will be described in detail below. In the following detailed description, numerous specific details are set forth in order to provide a thorough understanding of the present invention. However, it will be apparent to those skilled in the art that the present invention may be practiced without some of these specific details. The following description of the embodiments is only intended to provide a better understanding of the present invention by showing examples of the present invention. The present invention is in no way limited to any specific settings and methods set forth below, but covers any improvements, substitutions, and modifications of structures, methods, and devices without departing from the spirit of the present invention. In the drawings and the following description, well-known structures and technologies are not shown to avoid unnecessarily obscuring the present invention.

[0084] It should be noted that, without conflict, the embodiments of the present invention and the features in the embodiments may be combined with each other, and the various embodiments may refer to and cite each other. The present invention will be described in detail below with reference to the drawings and in combination with the embodiments.

[0085] As Figure 1 shown, when the present invention is adopted, the steps for determining the synchronous lifting and lowering control method of a numerically controlled hydraulic jack are as follows: A synchronous lifting and lowering control method for a numerically controlled hydraulic jack, where the numerically controlled hydraulic jack includes at least 3 jacks, each jack has two-stage cylinders, and the structure and parameters of each jack are the same. The specific steps are as follows:

[0086] Step 1: According to the characteristics of the hydraulic pump, the hydraulic first-stage cylinder S1, and the maximum lifting speed Vmax, calculate the minimum rotational speed F of the motor, and control the hydraulic pump motor to operate at a constant rotational speed;

[0087] Step 2: Obtain data through multiple groups of lifting and lowering experiments, and calculate a set of functional relationships between the lifting and lowering speeds of each hydraulic cylinder of each jack and the analog signal values of the proportional solenoid valves;

[0088] Step 3: Select the synchronous lifting and synchronous lowering programs, input the lifting speed value x and the lifting height H, and the control program determines whether x is less than or equal to Vmax. After meeting the condition, call the synchronous lifting program or the synchronous lowering program. The control program sets the 1# jack as the master jack, and the other jacks as the follower jacks;

[0089] Step 4: In the synchronous lifting and lowering control program, the control program monitors the displacement error between the follower jacks and the master jack, and determines which stage of the hydraulic cylinder is expanding or contracting according to the actual height of each jack, and accordingly determines which functional relationship between the lifting and lowering speed of the hydraulic cylinder and the analog signal value of the proportional solenoid valve should be called to control the output analog signal value of the proportional solenoid valve. At the same time, the control program monitors |△L 21 |, |△L 31 |,... |△L n1Is it greater than △L? Is the real-time height of each top reaching the maximum height (the minimum height is zero)? Has the lifting height been reached?

[0090] Step 5: The control program judges the positive and negative values of the displacement error between the follower top and the driving top. When it is positive, the control program decelerates the follower top; when it is negative, the control program accelerates the follower top, and then returns to Step 4 to run in a loop.

[0091] Step 6: The control program detects ∣△L 21 ∣, ∣△L 31 ∣,... ∣△L n1 ∣ greater than △L? The synchronous lifting action stops. Analyze and find the reason. After troubleshooting, restart the synchronous lifting and return to Step 3.

[0092] Step 7: The control program detects that the lifting height has been reached, or in the synchronous lifting control, the real-time height of any top reaches the maximum height, and in the synchronous lowering control, the real-time height of any top reaches the minimum height of zero. The synchronous lifting program ends and each top stops moving.

[0093] Embodiment 1

[0094] The jack system involved in the described method has 3 tops, and each top has two-stage cylinders. The structures and parameters of the 3 tops are the same. The present invention makes a detailed description of the calculations, test data processing, top state judgment, synchronous data processing, and control adjustment methods involved in the first-stage cylinder of the No. 1 top and the first-stage cylinder of the No. 2 top during synchronous lifting control:

[0095] Step 1: Calculate and determine the hydraulic pump motor speed according to the cross-sectional area of the first-stage cylinder of each top and the maximum lifting speed of the top.

[0096] According to the characteristics of the hydraulic pump and the motor, the cross-sectional area of the first-stage cylinder of the jack and the maximum lifting speed Vmax of the top, based on the formula:

[0097] Q = S1 × Vmax (1)

[0098] F = Q ÷ M = S1 × Vmax ÷ M (2)

[0099] Calculate and determine that the hydraulic pump motor runs at 1.1*F speed.

[0100] Where:

[0101] Q is the maximum flow value that the hydraulic pump needs to provide, S1 is the cross-sectional area of the first-stage cylinder of the top, Vmax is the maximum lifting speed of the jack, and M is the flow coefficient of the hydraulic pump.

[0102] Step 2: Obtain the functional relationship between the lifting speed of the hydraulic cylinder of each top and the analog signal value of the proportional solenoid valve through experiments.

[0103] Control Figure 2 Regarding the relationship between the analog input value of the proportional solenoid valve and the opening degree of the solenoid valve, a jacking test was conducted on the first-stage cylinders of Jack 1 and Jack 2. The rising speed of the jacks was measured under different assigned opening degrees of the solenoid valves. After calculation and processing of the data, the functional relationship between the lifting speed x of the hydraulic cylinder and the analog signal value Y of the proportional solenoid valve was obtained:

[0104] Y 1 = a 11 x 2 + b 11 X + c 11 (3)

[0105] Y 2 = a 21 x 2 + b 21 X + c 21 (3 - 2)

[0106] Step 3: Set one of the jacks as the active jack and the other jacks as follower jacks. Each jack starts synchronous lifting or synchronous lowering according to the set lifting speed value x and lifting height H.

[0107] Select the synchronous lifting program, input the lifting speed value x and the lifting height H. The control program determines whether x is less than or equal to Vmax. After meeting the condition, the synchronous lifting program is called, and the control program sets Jack 1 as the active jack and Jacks 2 and 3 as follower jacks.

[0108] Step 4: Read and record the displacement values of each jack in real time, as well as the displacement error value between the active jack and one of the follower jacks.

[0109] The control system reads the position values L 10 、L 20 of Jack 1 and Jack 2, sets them as the initial values and saves them. And the control system reads the position values L 1t 、L 2t of Jack 1 and Jack 2 in real time during synchronous lifting and lowering, and calculates the displacement values of the two jacks through Formulas (15) and (16):

[0110] △L 1 = L 1t - L 10 (15)

[0111] △L 2 = L 2t - L 20 (16)

[0112] And calculates the displacement error value of the two jacks through Formula (21):

[0113] △L 21 = △L2 -△L 1 (21)

[0114] Meanwhile, the control system determines the positions of the two pistons in each cylinder stage through Equation (24):

[0115] 0 < L 1t ≤ L 1 (24 - 1)

[0116] 0 < L 2t ≤ L 1 (24 - 2)

[0117] Thus, the control system determines that both the 1# piston and the 2# piston are in the first-stage cylinder position, and the system will call the functional relationship as follows:

[0118] Y 1 = a 11 x 2 + b 11 X + c 11 (3)

[0119] Y 12 = a 21 x 2 + b 21 X + c 21 (3 - 2)

[0120] The control system detects 0 < △L 21 < △L, or -△L < △L 21 < 0, and thus determines the speed difference between the 2# piston and the 1# piston, and the functional correction relationship between the lifting speed x of the 2# piston hydraulic cylinder and the analog signal value Y of the proportional solenoid valve is:

[0121]

[0122] When the control system detects 0.5 ≤ △L 21 it indicates that the synchronization accuracy is too poor, and the synchronous lifting action automatically stops. After the user finds the cause and eliminates the fault, the synchronous lifting action of the jacks is continued.

[0123] When the control system detects:

[0124] L 1t = L 1 + L 2 (33)

[0125] or L 2t = L 1 + L 2 (34)

[0126] The No. 1 jack or the No. 2 jack has reached the high or low limit position, and the synchronous lifting action automatically ends.

[0127] When the control system detects that:

[0128] △L 1 ≥H (35)

[0129] or △L 2 ≥H(36)

[0130] The required movement displacement of the No. 1 jack or the No. 2 jack has been reached, and the synchronous lifting action automatically ends.

[0131] Embodiment 1

[0132] It is known that: the cross-sectional area of the first-stage hydraulic cylinder of 3 jacks S1 = 29865mm 2 、S2 = 18869mm 2 , the maximum lifting speed of the jack Vmax = 2mm / s, the maximum allowable synchronous error ΔL is 0.5mm, the height of the first-stage hydraulic cylinder of the top L1 = 665mm, L2 = 665mm, and the oil supply of the hydraulic pump motor at a speed of 1500 revolutions per minute is 3.3L / minute.

[0133] Step 1: Calculate the speed of the hydraulic pump motor,

[0134] Q = 29865×2×60 = 3583800mm 3 / minute

[0135] F = 3583800÷3300000×1500 = 1629 revolutions per minute

[0136] Select the motor speed as 1.1*1629 and round it up to 100 revolutions per minute.

[0137] Step 2: Obtain data through the lifting experiment on the first-stage cylinder of the No. 1 top and the first-stage cylinder of the No. 2 top. The test data are shown in Figure 5 、 Figure 6 , and through calculation, the function relation groups of the lifting speeds of the first-stage cylinder of the No. 1 top and the first-stage cylinder of the No. 2 top and the numerical values of the analog signals of the proportional solenoid valves are obtained as shown in Figure 3 、 Figure 4 :

[0138] The first-stage cylinder of the No. 1 top rises: Y 1 = 837.15x 2 + 4519.5x + 439.71

[0139] The first-stage cylinder of the No. 2 top rises: Y 2 = 854.72x 2 + 4598.3x+385.66

[0140] Step 3: Input a lifting speed value of 1 mm / s and a lifting height of 100 mm, select the synchronous lifting program, and control to call the synchronous lifting program after detecting that the input lifting speed value is less than or equal to 2 mm / s. Set the 1# jack as the active jack and the 2# jack as the follower jack.

[0141] Step 4: At the start moment of the synchronous lifting motion control program, the control program reads the initial position L of the 1# jack's motion 10 value 500, and the initial position L of the 2# jack's motion 20 value 500. At the same time, it is detected that 0 < L 1t < 665, 0 < L 2t < 665. Therefore, both jacks are in the first-stage cylinder position, and both jacks are in the synchronous lifting state. The functional relationship between the speed and the analog signal value of the proportional solenoid valve called by the control system is:

[0142] Y 1 = 837.15x 2 + 4519.5x + 439.71

[0143] and Y 2 = 854.72x 2 + 4598.3x + 385.66

[0144] The analog signal value Y of the proportional solenoid valve of the 1# jack 1 = 837.15 × 1 2 + 4519.5 × 1 + 439.71 = 5796.36, rounded to 5796.

[0146] The analog signal value Y of the proportional solenoid valve of the 2# jack 2 = 854.72 × 1 2 + 4598.3 × 1 + 385.66 = 5838.68, rounded to 5839.

[0147] When the control system detects that the real-time height L of the 1# jack 1t is 540.00 and the real-time height L of the 2# jack 2t is 540.01, the displacement △L of the 1# jack 1 = 540 - 500 = 40, and the displacement △L of the 2# jack 12 = 540.01 - 500 = 40.01. The displacement error value △L of the two jacks 21 = 40.01 - 40 = 0.01 < 0.5. At the same time, 0 < L 1t < 1330 and 0 < L 2t < 1330. The system continues to execute Step 5.

[0148] Step 5: The system detects △L 21= 0.01 > 0, the movement speed of the 1# top is slower than that of the 2# top. The control system decelerates the 2# top. The function correction relationship between the lifting speed of the 2# top hydraulic cylinder and the analog signal value of the proportional solenoid valve is:

[0149] The integer value of the analog signal of the proportional solenoid valve of the 2# top is taken as 5216, and the system returns to step 4 for cyclic operation. At the same time, the lifting speed of the 2# top will decrease, and △L 21 will approach 0 from 0.01, and the analog signal value of the proportional solenoid valve of the 2# top will approach 5839 from 5216. When the value of △L 21 remains stable, the actual speeds of the 1# top and the 2# top will finally be the same until the synchronous lifting action ends.

[0151] Step 6: When the control system detects that △L 21 ≥ 0.5, the synchronous lifting action stops. Analyze and find the cause. After troubleshooting, restart the synchronous lifting and return to step 3.

[0152] Step 7: When the control program detects that the lifting height △L 1 ≥ 100 or △L 2 ≥ 100, the synchronous lifting program ends, and each top stops moving. At the same time, in all synchronous lifting programs, the control system will detect the real-time heights L 1t 、L 2t 、L 3t of the three tops to see if they have reached 1330 mm. In all synchronous lowering programs, the control system will detect the real-time heights L 1t 、L 2t 、L 3t of the three tops to see if they have reached 0 mm. Once any top meets the condition, the synchronous program will end immediately, and each top will stop moving.

Claims

1. A method for controlling the synchronous lifting of multiple jacks of a numerically controlled hydraulic jack, which is applied to numerically controlled hydraulic jacks, wherein the control system controls n jacks to be lifted and lowered simultaneously, n≧3, and each jack includes a proportional solenoid valve and an m-level telescopic hydraulic cylinder, m≧3; the method is characterized in that: The steps include: Step 1: Calculate the minimum motor speed F according to the cross-sectional area of ​​the first-stage telescopic hydraulic cylinder and the maximum lifting speed Vmax, and control the hydraulic pump motor to run at a constant speed; Step 2: Calculate the functional relationship between the lifting speed of each hydraulic cylinder at each level and the analog signal value of the proportional solenoid valve through multiple lifting experiments; Step 3: Set one of the tops as the active top and the other tops as the follower tops. Each top starts synchronous lifting or synchronous lowering according to the set lifting speed value x and lifting height H; Step 4: Determine the hydraulic cylinder level in real time according to the actual height of each top, so as to determine the function relationship between the lifting speed of the corresponding hydraulic cylinder level and the analog signal value of the proportional solenoid valve to control the analog signal value of the output proportional solenoid valve; Step 5: Monitor the displacement error between the follower top and the active top in real time, and correct the speed of the follower top according to the displacement error; when the displacement error exceeds the displacement error threshold, the synchronous lifting action stops; Step 6: It is detected that the lifting height has been reached, or in the synchronous lifting control, the real-time height of any top reaches the maximum height; in the synchronous lowering control, the real-time height of any top reaches the minimum height of zero, the synchronous lifting program ends and stops.

2. A method for controlling and adjusting the synchronous lifting of multiple CNC hydraulic jacks according to claim 1, characterized in that: The minimum speed of the motor in step 1 is obtained by the following formula: Q=S1×Vmax(1) F=Q÷M=S1×Vmax÷M (2) Set the hydraulic pump motor to run at 1.1*F speed; in: Q is the maximum flow value that the hydraulic pump needs to provide, S1 is the cross-sectional area of ​​the first-stage cylinder, Vmax is the maximum lifting speed of the jack, and M is the flow coefficient of the hydraulic pump.

3. The method for controlling and adjusting the synchronous lifting of multiple CNC hydraulic jacks according to claim 1 is characterized in that: The functional relationship group in step 2 is obtained through the following experimental process: Output analog value to the proportional solenoid valve, measure and record the lifting speed of the top, and obtain the functional relationship between the lifting speed x of the hydraulic cylinder and the analog signal value Y of the proportional solenoid valve after multiple tests on each cylinder of each top; 1# top cylinder rises: Y1=a 11 x 2 +b 11 X+c 11 (3) 1# top secondary cylinder rises: Y1=a 12 x 2 +b 12 X+c 12 (4) …… 1# top m-level cylinder rises: Y1=a 1m x 2 +b 1m X+c 1m (5) …… n# The top cylinder rises: Y n =a n1 x 2 +b n1 X+c n1 (6) n# The top secondary cylinder rises: Y n =a n2 x 2 +b n2 X+c n2 (7) …… n# top m-level cylinder rises: Y n =a nm x 2 +b nm X+c nm (8) 1# top cylinder descends: Y1=Ax 2 +B 11 X+C 11 (9) 1# top second cylinder descends: Y1=A 12 x 2 +B 12 X+C 12 (10) …… 1# top m-level cylinder descends: Y1=A 1m x 2 +B 1m X+C 1m (11) …… n# The top cylinder descends: Y n =A n1 x 2 +B n1 X+C n1 (12) n# The top second cylinder descends: Y n =A n2 x 2 +B n2 X+C n2 (13) …… n# top m-level cylinder drops: Y n =A nm x 2 +B nm X+C nm (14) in: Y1, Y2...Y n They are the analog signal values ​​of the proportional solenoid valves of 1# top, 2# top, ...n# top, respectively. x is the lifting speed of the top. a11, a12, ...a1m, ...an1, an2, ...anm, A11, A12, ...A1m, ...An1, An2, ...Anm are all constants.

4. A method for controlling and adjusting the synchronous lifting of multiple CNC hydraulic jacks according to claim 3, characterized in that: In step 3, it is determined whether the hydraulic cylinder lifting speed x is less than or equal to Vmax, and if the condition is met, the synchronous lifting program or the synchronous lowering program is called.

5. The method for controlling and adjusting the synchronous lifting of multiple CNC hydraulic jacks according to claim 1 is characterized in that: In step 4, the heights of the hydraulic cylinders at each level are L1, L2, ... m The control system reads the position values ​​of each top at all times during synchronous lifting, which are L 1t , L 2t ...L nt , calculate and determine the hydraulic cylinder level m1 according to the following formula: 0+L1+…L m1-1 <L n1t ≤L1+…L m1 {m≥m1≥1,n1∈(1,n)} (24)。 6. The method for controlling and adjusting the synchronous lifting of multiple CNC hydraulic jacks according to claim 5 is characterized in that: In step 5, the process of correcting the speed of the follower top according to the displacement error includes the positive and negative values ​​of the displacement error. When the displacement error is positive, the control program decelerates the follower top, and when the displacement error is negative, the control program accelerates the follower top.

7. The method for controlling and adjusting the synchronous lifting of multiple CNC hydraulic jacks according to claim 6 is characterized in that: In step 5, it is assumed that the 1# top, 2# top, ... n# top are synchronously ascended by m1-level cylinders respectively, and the control system detects that 0 < △L 21 <△L, indicating that the speed of 2# top is faster than that of 1# top, the control system will reduce the speed of 2# top and assign it The control system detects -△L<△L 21 <0, indicating that the speed of 2# top is slower than that of 1# top, the control system will increase the speed of 2# top and assign it Therefore, when the 2# top is in synchronous control, the control system corrects the function relationship between the lifting speed x of the 2# top hydraulic cylinder and the analog signal value Y of the proportional solenoid valve as follows: Similarly: When descending synchronously, the functional correction relationship between the lifting speed x of the follower top hydraulic cylinder and the analog signal value Y of the proportional solenoid valve is:

8. The method for controlling and adjusting the synchronous lifting of multiple CNC hydraulic jacks according to claim 7 is characterized in that: In step 6, when the control system detects L during synchronous rise 1t , L 2t……Lnt The height of any top in the middle is greater than or equal to L1+L2+...L n , L is detected during the synchronous descent 1t , L 2t……Lnt The height of any top is less than or equal to 0, or △L1, △L2...△L n When the synchronous lifting displacement of any top reaches H, the control system will close all proportional solenoid valves and the lifting action of all tops will end.

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