Coaxial double-crank plunger pump constant-pressure motion control method based on PLC and PLC

Abstract

The invention discloses an asymmetric coaxial double-crank plunger pump constant-pressure motion control method based on a PLC (Programmable Logic Controller), which comprises the following steps of: determining a connecting rod working displacement function of a connecting rod plunger connecting part in a working process according to mechanical parameters of a coaxial double-crank plunger pump; calculating a first-order derivative of the working displacement function of the connecting rod; determining a crank driving side angular velocity function according to the piston superposition output velocity; performing phase shifting on the crank driving side angular velocity function rightwards for a preset radian to obtain a target angular velocity function; and taking the target angular velocity function as a driving angular velocity function of the PLC. The driving motor is controlled to drive the asymmetric double-crank plunger pump to work through the crank driving side angular velocity function based on the PLC, so that the stacking velocity of the two pistons is a constant value, the flow of fluid output by the plunger pump is constant, the pressure of a pump outlet is also constant, and the working efficiency is improved. And the requirement of constant fluid flow required by an automobile spraying process can be met.

Description

Technical Field

[0001] The present invention relates to the field of computer control technology, and in particular to a PLC-based coaxial double-crank plunger pump constant pressure motion control method and device. Background Art

[0002] The PCB of the existing ACS module is developed using a single-board computer, has digital I / O, AD, and DA interfaces, and is encapsulated in an aluminum profile. The ACS module controls the coaxial double-crank plunger pump to rotate from the origin. The ACS module outputs different 4-20mA analog current values ​​according to the position change of the asymmetric double crank to accurately adjust the speed of the inverter, so as to control the pump outlet to be in a constant pressure state.

[0003] During the process of ACS controlling the electric pump, the pressure fluctuation of the liquid flow at the pump outlet is large, and the fluid that meets the requirements of the automobile spraying process cannot be provided. In addition, the above faults need to be replaced with a new ACS controller to alleviate the pressure fluctuation problem, and the replacement cost is high. In addition, the ACS PCB board is developed for a single-chip microcomputer. After measuring and analyzing its electronic circuit structure with an oscilloscope, it was found that its anti-interference ability is relatively weak, and a large amount of high-frequency noise can be measured entering the single-chip microcomputer on the digital quantity pin. At the same time, the ACS control program cannot be open source, and users and integrators cannot flexibly modify the ACS program. Once the ACS control system fails, it cannot be monitored online and the running code cannot be modified. This makes the equipment maintenance and resumption of production relatively long, and the replacement and maintenance costs are high. In addition, the ACS single-board computer tends to be in the direction of electronic engineering. Electronic engineers need to have a lot of electronic knowledge and single-chip microcomputer programming knowledge, which increases the difficulty for electrical personnel to diagnose and troubleshoot electronic faults. Summary of the invention

[0004] In order to solve the above problems existing in the prior art, the present invention provides a PLC-based coaxial double crank plunger pump constant pressure motion control method, device, electronic equipment and storage medium. The technical problem to be solved by the present invention is achieved through the following technical solutions:

[0005] A first aspect of an embodiment of the present invention provides a PLC-based coaxial double crank plunger pump constant pressure motion control method, comprising the following steps:

[0006] Determine the connecting rod working displacement function of the connecting rod-plunger connection portion during operation according to the mechanical parameters of the coaxial double crank plunger pump; wherein the mechanical parameters include: crank radius, connecting rod length, and the movement angle between the crank limit position of the connecting rod moving to the maximum stroke and the crank movement position outside the crank limit position;

[0007] Calculating the first-order derivative of the connecting rod working displacement function to obtain the first-order derivative of displacement;

[0008] Determine the crank driving side angular velocity function according to the superimposed output speed of the piston, the gear reduction ratio of the reducer, the arc difference of the motion positions of the two cranks and the first-order derivative of the displacement;

[0009] Shifting the crank driving side angular velocity function to the right by a preset arc to obtain a target angular velocity function;

[0010] The target angular velocity function is used as the driving angular velocity function of the PLC controller; wherein the POS terminal of the PLC controller is used to input a signal for measuring the position of a mechanical crank, the TDC terminal is used to input a signal for measuring the reset origin of the mechanical crank, the 4-20mA current signal terminal is used to input a pressure signal for measuring the output end of the plunger pump, and the 4-20mA current output signal terminal is used to control the operating frequency of the frequency converter.

[0011] In one embodiment of the present invention, determining the connecting rod working displacement function of the connecting rod-plunger connection portion during operation according to the mechanical parameters of the coaxial double crank plunger pump comprises:

[0012] The connecting rod working displacement function of the connecting rod plunger connection during operation is determined based on the ratio of the crank radius to the connecting rod length, the connecting rod length, the movement angle between the crank limit position when the connecting rod moves to the maximum stroke and the crank movement position outside the crank limit position, and the sine function.

[0013] In one embodiment of the present invention, the expression of the connecting rod working displacement function is:

[0014]

[0015] Among them, S represents the connecting rod working displacement function, R represents the crank radius, x represents the movement angle, and L represents the connecting rod length.

[0016] In one embodiment of the present invention, the expression of the crank driving side angular velocity function is:

[0017] ω Motor =V 设 *RE / (abs(S'(x))+abs(S'(xD)));

[0018] Among them, ω Motor Represents the angular velocity function of the crank drive side, 0.0 = <V 设 <0.0105m / s, V 设 represents the superimposed output speed of the piston, RE represents the gear ratio of the reducer, S'(x) represents the first-order derivative of the displacement, and D represents the arc difference of the motion position of the two cranks;

[0019] The expression of the target angular velocity function is:

[0020] ωM =V 设 *RE / (abs(S'(x-β))+abs(S'(xD-β)));

[0021] Among them, ω M represents the target angular velocity function, β represents the preset radian, π / 4≤β<5π / 18.

[0022] A second aspect of an embodiment of the present invention provides a PLC-based asymmetric coaxial double crank plunger pump constant pressure motion control device, comprising:

[0023] A first determination module is used to determine the connecting rod working displacement function of the connecting rod-plunger connection part during operation according to the mechanical parameters of the coaxial double crank plunger pump; wherein the mechanical parameters include: crank radius, connecting rod length, and movement angle between the crank limit position of the connecting rod moving to the maximum stroke and the crank movement position outside the crank limit position;

[0024] A first calculation module is used to calculate the first-order derivative of the connecting rod working displacement function to obtain the first-order derivative of displacement;

[0025] A second determination module is used to determine the crank driving side angular velocity function according to the superimposed output speed of the piston, the gear reduction ratio of the reducer, the arc difference of the motion positions of the two cranks and the first-order derivative of the displacement;

[0026] A second calculation module is used to shift the crank driving side angular velocity function to the right by a preset arc to obtain a target angular velocity function;

[0027] A setting module is used to use the target angular velocity function as the driving angular velocity function of the PLC controller; wherein the POS terminal of the PLC controller is used to input a signal for measuring the position of a mechanical crank, the TDC terminal is used to input a signal for measuring the reset origin of the mechanical crank, the 4-20mA current signal terminal is used to input a pressure signal for measuring the output end of the plunger pump, and the 4-20mA current output signal terminal is used to control the operating frequency of the inverter.

[0028] In one embodiment of the present invention, determining the connecting rod working displacement function of the connecting rod-plunger connection portion during operation according to the mechanical parameters of the coaxial double crank plunger pump comprises:

[0029] The connecting rod working displacement function of the connecting rod plunger connection during operation is determined based on the ratio of the crank radius to the connecting rod length, the connecting rod length, the movement angle between the crank limit position when the connecting rod moves to the maximum stroke and the crank movement position outside the crank limit position, and the sine function.

[0030] In one embodiment of the present invention, the expression of the connecting rod working displacement function is:

[0031]

[0032] Among them, S represents the connecting rod working displacement function, R represents the crank radius, x represents the movement angle, and L represents the connecting rod length.

[0033] In one embodiment of the present invention, the expression of the crank driving side angular velocity function is:

[0034] ω Motor =V 设 *RE / (abs(S'(x))+abs(S'(xD)));

[0035] Among them, ω Motor Represents the angular velocity function of the crank drive side, 0.0 = <V 设 <0.0105m / s, V 设 represents the superimposed output speed of the piston, RE represents the gear ratio of the reducer, S'(x) represents the first-order derivative of the displacement, and D represents the arc difference of the motion position of the two cranks;

[0036] The expression of the target angular velocity function is:

[0037] ω M =V 设 *RE / (abs(S'(x-β))+abs(S'(xD-β)));

[0038] Among them, ω M represents the target angular velocity function, β represents the preset radian, π / 4≤β<5π / 18.

[0039] A third aspect of an embodiment of the present invention provides an electronic device, comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein when the processor executes the program, a PLC-based coaxial double-crank plunger pump constant pressure motion control method provided in the first aspect of an embodiment of the present invention is implemented.

[0040] The fourth aspect of an embodiment of the present invention provides a computer-readable storage medium having a computer program stored thereon. When the computer program is executed by a processor, the constant pressure motion control method of a coaxial double-crank piston pump based on PLC provided in the first aspect of an embodiment of the present invention is implemented.

[0041] Beneficial effects of the present invention:

[0042] The present invention controls the driving motor to drive the asymmetric double crank plunger pump to work by using the crank driving side angular velocity function based on the PLC controller, so that the superposition speed of the two pistons is a constant value, therefore, the fluid flow output by the plunger pump is constant, and the pressure at the pump outlet is also constant, which can meet the requirements of the constant fluid flow required by the automobile spraying process. Moreover, the anti-interference ability of the constant pressure motion control electrical of the asymmetric double crank plunger pump is improved by the PLC controller. At the same time, the control code based on the PLC controller can be independently developed, which reduces the difficulty of monitoring, modifying and querying code information, and locates the fault point immediately and quickly, and the time cost and accessories cost in the maintenance process are relatively low. In addition, the PLC controller is easy for the staff to perform fault diagnosis and troubleshooting. Therefore, the asymmetric double crank plunger pump constant pressure motion controller based on PLC greatly reduces the production cost of automobile companies in the spraying sector, and at the same time expands the operability of electrical engineering personnel in terms of maintenance and preservation.

[0043] Other features and advantages of the present invention will be described in the following description, and partly become apparent from the description, or understood by practicing the present invention. The purpose and other advantages of the present invention can be realized and obtained by the structures particularly pointed out in the written description, claims, and drawings.

[0044] The technical solution of the present invention is further described in detail below through the accompanying drawings and embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0045] The accompanying drawings are used to provide a further understanding of the present invention and constitute a part of the specification. Together with the embodiments of the present invention, they are used to explain the present invention and do not constitute a limitation of the present invention. In the accompanying drawings:

[0046] Figure 1 A schematic flow chart of a PLC-based coaxial double crank plunger pump constant pressure motion control method provided in an embodiment of the present invention;

[0047] Figure 2a A schematic diagram of the initial position of a crank connecting rod of a connecting rod working displacement function provided by an embodiment of the present invention;

[0048] Figure 2b A schematic diagram of the crank connecting rod position after the independent variable x of the connecting rod working displacement function provided by an embodiment of the present invention moves by an angle α;

[0049] Figure 2c A schematic diagram of a preset arc of crank position angle offset provided by an embodiment of the present invention;

[0050] Figure 3 A Matlab simulation diagram of the crank driving side angular velocity function provided by an embodiment of the present invention;

[0051] Figure 4 A function graph obtained by programming the crank driving side angular velocity function provided by an embodiment of the present invention in CAD;

[0052] Figure 5 The target angular velocity function Matlab simulation diagram provided by the embodiment of the present invention;

[0053] Figure 6 A schematic diagram of an electronic cam function image in which the angular velocity of the motor is tracked in real time as the angle changes under the flow mode provided by an embodiment of the present invention;

[0054] Figure 7 A schematic diagram of inputting angular velocity, superimposed velocity of "piston 1" and "piston 2" using a PLC+UG / NX joint virtual motion simulation interface provided in an embodiment of the present invention;

[0055] Figure 8 A schematic diagram of the velocity curves of two pistons of an asymmetric coaxial double crank plunger modeled in uniform motion simulation using Inventor provided in an embodiment of the present invention;

[0056] Fig. 9 The embodiment of the present invention provides Figure 8 Schematic diagram of the superposition velocity image obtained by taking the absolute values ​​of the piston velocities V[1] and V[2] and summing them up;

[0057] Fig.10 A structural block diagram of a PLC-based coaxial double-crank plunger pump constant pressure motion controller provided in an embodiment of the present invention. DETAILED DESCRIPTION

[0058] The present invention is further described in detail below with reference to specific embodiments, but the embodiments of the present invention are not limited thereto.

[0059] like Figure 1 As shown, the first aspect of the embodiment of the present invention provides a constant pressure motion control method of a coaxial double crank plunger pump based on PLC, comprising the following steps:

[0060] Step 11, determining the connecting rod working displacement function of the connecting rod-plunger connection portion during operation according to the mechanical parameters of the coaxial double crank plunger pump.

[0061] The mechanical parameters include: a crank radius, a connecting rod length, and a movement angle between a crank limit position where the connecting rod moves to a maximum stroke and a crank movement position outside the crank limit position.

[0062] Step 12, calculating the first-order derivative of the connecting rod working displacement function to obtain the first-order derivative of displacement.

[0063] Step 13, determining the angular velocity function of the crank driving side according to the superimposed output speed of the piston, the gear reduction ratio of the reducer, the arc difference of the motion positions of the two cranks, and the first-order derivative of the displacement.

[0064] Step 14, shifting the crank driving side angular velocity function to the right by a preset arc to obtain a target angular velocity function.

[0065] Step 15: Use the target angular velocity function as the driving angular velocity function of the PLC controller.

[0066] Among them, the POS terminal of the PLC controller is used to input the signal for measuring the position of the mechanical crank, the TDC terminal is used to input the signal for measuring the reset origin of the mechanical crank, the 4~20mA current signal terminal is used to input the pressure signal for measuring the output end of the plunger pump, and the 4~20mA current output signal terminal is used to control the operating frequency of the inverter.

[0067] In this embodiment, the drive motor is driven to drive the asymmetric double crank plunger pump based on the PLC controller with the crank driving side angular velocity function, so that the superposition speed of the two pistons is a constant value, therefore, the fluid flow rate output by the plunger pump is constant, and the pressure at the pump outlet is also constant, which can meet the requirements of the constant fluid flow rate required by the automobile spraying process. Moreover, the anti-interference ability of the asymmetric double crank plunger pump constant pressure motion control electrical is improved based on the PLC controller. At the same time, the control code based on the PLC controller can be independently developed, which reduces the difficulty of monitoring, modifying and querying code information, and locates the fault point immediately and quickly, and the time cost and accessories cost in the maintenance process are relatively low. In addition, the PLC controller is easy for staff to perform fault diagnosis and troubleshooting. Therefore, the asymmetric double crank plunger pump constant pressure motion controller based on PLC greatly reduces the production cost of automobile companies in the spraying sector, and at the same time expands the operability of electrical engineering personnel in terms of maintenance and preservation.

[0068] A second aspect of an embodiment of the present invention provides a PLC-based coaxial double crank plunger pump constant pressure motion control method, comprising the following steps:

[0069] Step 21, determining the connecting rod working displacement function of the connecting rod-plunger connection portion during operation according to the mechanical parameters of the coaxial double crank plunger pump.

[0070] The mechanical parameters include: a crank radius, a connecting rod length, and a movement angle between a crank limit position where the connecting rod moves to a maximum stroke and a crank movement position outside the crank limit position.

[0071] In this embodiment, the asymmetric double crank plunger pump uses an asynchronous motor as the prime mover, the prime mover is powered by a frequency converter, the reducer and the crank are designed as an integral mechanical mechanism, the crank and the connecting rod form a rotating pair, and finally the connecting rod drives the piston of the asymmetric double crank plunger pump to move in the vertical direction. The movement of the three-phase asynchronous motor drives the reducer to move synchronously; after the reducer moves, the crank drives the connecting rod to move, and finally the connecting rod drives the piston to reciprocate up and down.

[0072] Among them, the POS terminal of the PLC controller is used to input the signal for measuring the position of the mechanical crank (that is, the arc of the crank movement), and the TDC terminal is used to input the signal for measuring the reset origin of the mechanical crank. The reset origin is the arc of the crank movement calculated from 0 after the sensor detects the reset origin. The 4-20mA current signal terminal is used to input the pressure signal of the output end of the plunger pump, and the 4-20mA current output signal terminal is used to control the operating frequency of the inverter.

[0073] The specific steps of this step are: according to the ratio of crank radius to connecting rod length, connecting rod length, the movement angle between the crank limit position of the connecting rod moving to the maximum stroke and the crank movement position outside the crank limit position, and the sine function, determine the connecting rod working displacement function of the connecting rod plunger connection during the working process. The expression of the connecting rod working displacement function is:

[0074]

[0075] Among them, S represents the connecting rod working displacement function, R represents the crank radius, x represents the movement angle, and L represents the connecting rod length.

[0076] Here, for example, Figure 2a and Figure 2b As shown, the crank radius R is 0.06m (the length of OA and OE), the connecting rod length L is 0.35m, the gear reduction ratio is 75.16:1 (generally an integer), the two crank angles differ by 78° (asymmetric), and the movement angle x = ∠AOB between the crank limit position A corresponding to the connecting rod moving upward to the maximum stroke and the crank movement position B outside the crank limit position A (which can also be considered as the initial position of the function model). That is, the movement trajectory of the crank (the movement trajectory of the connection between the crank and the connecting rod is simplified as the movement trajectory of the crank) is a circle with O as the center and a radius of R. When the connecting rod moves upward to the maximum stroke, the crank is at position A. When working, the crank moves from A to a certain position B, that is, after x moves by an angle of α, E is the position of the other crank during the working process. S is the displacement function of the connecting rod plunger connection C or the connecting rod plunger connection D during the working process, which is calculated according to the trigonometric function relationship of the triangle. The connecting rod plunger connection is also the connection between the connecting rod and the plunger.

[0077] The crank radius R is 0.06m (the length of OA and OE), the connecting rod length L is 0.35m, the gear reduction ratio is 75.16:1 (generally an integer), and the connecting rod working displacement function when the angle between the two cranks is 78° is:

[0078]

[0079] Step 22, calculating the first-order derivative of the connecting rod working displacement function to obtain the first-order derivative of displacement.

[0080] For example, when the crank radius R is 0.06m (the length of OA and OE), the connecting rod length L is 0.35m, the gear reduction ratio is 75.16:1 (generally an integer), and the first-order derivative of the connecting rod working displacement function when the angle between the two cranks is 78° (radian is 39π / 90) is:

[0081] S'(x)=-(7*sin(x-asin((171*sin(x)) / 1000))*cos(x)) / (20*sin(x)^2)-(7*cos(x-asin((171*si n(x)) / 1000))*((171*cos(x)) / (1000*(1-(29241*sin(x)^2) / 1000000)^(1 / 2))-1)) / (20*sin(x)).

[0082] Step 23, determining the angular velocity function of the crank driving side according to the superimposed output speed of the piston, the gear reduction ratio of the reducer, the arc difference of the motion positions of the two cranks, and the first-order derivative of the displacement.

[0083] Here, the piston superposition output speed is the sum of the absolute values ​​of the output speeds of the two pistons corresponding to the two cranks. The piston superposition output speed can be set as needed. Assume that the piston moves in the vertical direction and the piston superposition output speed is V 设 , since the piston of the plunger pump does work during both the rising and falling periods, the absolute value of the first-order derivative is taken, and the angle difference between the two cranks is considered. The expression of the angular velocity function of the crank driving side is:

[0084] ω Motor =V 设 *RE / (abs(S'(x))+abs(S'(xD)));

[0085] Among them, ω Motor Represents the angular velocity function of the crank drive side, 0.0 = <V 设 <0.0105m / s, V 设 represents the superimposed output speed of the piston, RE represents the gear reduction ratio of the reducer, S'(x) represents the first-order derivative of the displacement, and D represents the arc difference of the motion position of the two cranks.

[0086] For example, the expression of the crank driving side angular velocity function with the gear reduction ratio of the above reducer and the value of the arc difference of the motion position of the two cranks is: ω Motor =V 设 *75 / (abs(S'(x))+abs(S'(x-39π / 90))), this formula generates an image in Matlab as follows Figure 3 As shown, the function graph obtained by programming in CAD is as follows Figure 4 As shown, Figure 3 and Figure 4 The image shape is the same, therefore, both Matlab and AutoCAD programming methods verify the correctness of the function image.

[0087] Step 24, shift the crank driving side angular velocity function to the right by a preset arc to obtain a target angular velocity function. The above crank driving side angular velocity function is a function under an ideal state, but in actual applications, the position angle of the crank may have a certain deviation, such as Figure 2c As shown in , the position of the crank in the ideal state is at A, but the actual position of the crank at this moment is at B, with a difference of β radians. Position E is the position of the other crank. Therefore, the expression of the target angular velocity function is obtained by shifting the angular velocity function of the crank driving side to the right by β radians:

[0088] ω M =V 设 *RE / (abs(S'(x-β))+abs(S'(xD-β)));

[0089] Among them, ω M represents the target angular velocity function, β represents the preset radian, π / 4≤β<5π / 18.

[0090] For example, when the values ​​of the above mechanical parameters are substituted and β = π / 4, the expression of the target angular velocity function is: ω M =V 设 *75 / (abs(S'(x-π / 4))+abs(S'(x-33π / 180))), this formula generates the phase shift function image in Matlab as shown below Figure 5 shown.

[0091] Step 25: Using the target angular velocity function as the driving angular velocity function of the PLC controller.

[0092] ω M =V 设*75 / (abs(S'(x-π / 4))+abs(S'(x-33π / 180))) is written into Siemens S7-1200PLC. According to the manual of the electric pump, the inverter drive range is 0-80Hz. In the flow mode, the motor running angular velocity changes with the angle and tracks the electronic cam function image in real time. Figure 6 shown.

[0093] In this embodiment, PLC+UG / NX combined virtual motion simulation technology is used to illustrate the feasibility of the target angular velocity function. The simulation mechanical parameters use the values ​​of the above mechanical parameters. Figure 7 As shown in the figure, the top red line image is the input angular velocity image using the target angular velocity function, and the bottom red line image is the superposition velocity of "piston 1" and "piston 2", which is a constant value. According to the principle of fluid mechanics, the superposition velocity of the two pistons is constant, the fluid flow rate output by the pump is constant, and the pressure at the pump outlet is also constant. At the same time, the model is built by Odek Inventor and theoretical uniform motion simulation is performed. During the simulation process, the cam is used to rotate at a constant speed to drive the asymmetric coaxial double crank plunger, and the velocity curves of the two pistons are obtained as shown in the figure. Figure 8 As shown, Figure 8 The piston speeds V[1] and V[2] in the equation are taken in absolute values ​​and summed to obtain Fig. 9 From this we can see that Figure 5 and Fig. 9 The image shape is symmetrical about the horizontal axis, forming a completely complementary situation. Therefore, the result after adding the two is constant, which can meet the constant pressure production requirements.

[0094] like Fig.10 As shown, the third aspect of the embodiment of the present invention provides a PLC-based asymmetric coaxial double crank plunger pump constant pressure motion control device, comprising:

[0095] The first determination module 31 is used to determine the connecting rod working displacement function of the connecting rod-plunger connection part during operation according to the mechanical parameters of the coaxial double crank plunger pump; wherein the mechanical parameters include: crank radius, connecting rod length and movement angle between the crank limit position when the connecting rod moves to the maximum stroke and the crank movement position outside the crank limit position;

[0096] A first calculation module 32 is used to calculate the first-order derivative of the connecting rod working displacement function to obtain the first-order derivative of the displacement;

[0097] A second determination module 33 is used to determine the angular velocity function of the crank driving side according to the superimposed output speed of the piston, the gear reduction ratio of the reducer, the arc difference of the motion positions of the two cranks and the first-order derivative of the displacement;

[0098] The second calculation module 34 is used to shift the crank driving side angular velocity function to the right by a preset arc to obtain a target angular velocity function;

[0099] A module 35 is set up to use the target angular velocity function as the driving angular velocity function of the PLC controller; wherein the POS terminal of the PLC controller is used to input a signal for measuring the position of a mechanical crank, the TDC terminal is used to input a signal for measuring the reset origin of the mechanical crank, the 4-20mA current signal terminal is used to input a pressure signal for measuring the output end of the plunger pump, and the 4-20mA current output signal terminal is used to control the operating frequency of the inverter.

[0100] In one embodiment of the present invention, according to the mechanical parameters of the coaxial double crank plunger pump, the connecting rod working displacement function of the connecting rod-plunger connection portion during operation is determined, including:

[0101] The connecting rod working displacement function of the connecting rod plunger connection during operation is determined based on the ratio of the crank radius to the connecting rod length, the connecting rod length, the movement angle between the crank limit position when the connecting rod moves to the maximum stroke and the crank movement position outside the crank limit position, and the sine function.

[0102] In one embodiment of the present invention, the expression of the connecting rod working displacement function is:

[0103]

[0104] Among them, S represents the connecting rod working displacement function, R represents the crank radius, x represents the movement angle, and L represents the connecting rod length.

[0105] In one embodiment of the present invention, the expression of the crank driving side angular velocity function is:

[0106] ω Motor =V 设 *RE / (abs(S'(x))+abs(S'(xD)));

[0107] Among them, ω Motor Represents the angular velocity function of the crank drive side, 0.0 = <V 设 <0.0105m / s, V 设 represents the superimposed output speed of the piston, RE represents the gear ratio of the reducer, S'(x) represents the first-order derivative of the displacement, and D represents the arc difference of the motion position of the two cranks;

[0108] The expression of the target angular velocity function is:

[0109] ω M =V 设 *RE / (abs(S'(x-β))+abs(S'(xD-β)));

[0110] Among them, ω Mrepresents the target angular velocity function, β represents the preset radian, π / 4≤β<5π / 18.

[0111] The fourth aspect of an embodiment of the present invention provides an electronic device, including a memory, a processor, and a computer program stored in the memory and executable on the processor. When the processor executes the program, a PLC-based coaxial double-crank plunger pump constant pressure motion control method provided in the above-mentioned embodiment of the present invention is implemented.

[0112] The fifth aspect of the embodiment of the present invention also provides a computer-readable storage medium, on which a computer program is stored. When the computer program is executed by a processor, the steps of a PLC-based coaxial double-crank piston pump constant pressure motion control method provided in the above-mentioned embodiment of the present invention are implemented.

[0113] The memory may include a random access memory (RAM) or a non-volatile memory (NVM), such as at least one disk memory. Optionally, the memory may also be at least one storage device located away from the aforementioned processor.

[0114] The above-mentioned processor can be a general-purpose processor, including a central processing unit (CPU), a network processor (NP), etc.; it can also be a digital signal processor (DSP), an application specific integrated circuit (ASIC), a field programmable gate array (FPGA) or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware systems.

[0115] The method provided in the embodiment of the present invention can be applied to electronic devices. Specifically, the electronic device can be: a desktop computer, a portable computer, an intelligent mobile terminal, a server, etc. This is not limited here, and any electronic device that can implement the present invention belongs to the protection scope of the present invention.

[0116] As for the device / electronic device embodiment, since it is basically similar to the method embodiment, the description is relatively simple, and the relevant parts can be referred to the partial description of the method embodiment.

[0117] The present invention is described with reference to flowcharts and / or block diagrams of methods, devices (systems), and computer program products according to embodiments of the present invention. It should be understood that each process and / or block in the flowchart and / or block diagram, as well as the combination of processes and / or blocks in the flowchart and / or block diagram, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing device to produce a machine, so that the instructions executed by the processor of the computer or other programmable data processing device generate instructions for implementing the processes in the flowchart and / or block diagram. Figure 1 A process or multiple processes and / or boxes Figure 1 A device that provides the functions specified in a block or multiple blocks.

[0118] These computer program instructions may also be stored in a computer-readable memory capable of directing a computer or other programmable data processing device to operate in a specific manner, so that the instructions stored in the computer-readable memory produce an article of manufacture comprising an instruction device, which implements the process Figure 1 A process or multiple processes and / or boxes Figure 1 A function specified in one or more boxes.

[0119] These computer program instructions can also be loaded onto a computer or other programmable data processing device so that a series of operating steps are executed on the computer or other programmable device to produce a computer-implemented process, thereby providing instructions for implementing the process. Figure 1 A process or multiple processes and / or boxes Figure 1 A step that specifies a function in one or more boxes.

[0120] Obviously, those skilled in the art can make various changes and modifications to the present invention without departing from the spirit and scope of the present invention. Thus, if these modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalents, the present invention is also intended to include these modifications and variations.

Claims

1. A PLC-based asymmetric coaxial double crank piston pump constant pressure motion control method, characterized in that: The following steps are involved: Determine the connecting rod working displacement function of the connecting rod-plunger connection portion during operation according to the mechanical parameters of the coaxial double crank plunger pump; wherein the mechanical parameters include: crank radius, connecting rod length, and the movement angle between the crank limit position of the connecting rod moving to the maximum stroke and the crank movement position outside the crank limit position; Calculating the first-order derivative of the connecting rod working displacement function to obtain the first-order derivative of displacement; Determine the crank driving side angular velocity function according to the superimposed output speed of the piston, the gear reduction ratio of the reducer, the arc difference of the motion positions of the two cranks and the first-order derivative of the displacement; Shifting the crank driving side angular velocity function to the right by a preset arc to obtain a target angular velocity function; The target angular velocity function is used as the driving angular velocity function of the PLC controller; wherein the POS terminal of the PLC controller is used to input a signal for measuring the position of a mechanical crank, the TDC terminal is used to input a signal for measuring the reset origin of the mechanical crank, the 4-20mA current signal terminal is used to input a pressure signal for measuring the output end of the plunger pump, and the 4-20mA current output signal terminal is used to control the operating frequency of the frequency converter.

2. The method according to claim 1, characterized in that The method of determining the connecting rod working displacement function of the connecting rod-plunger connection portion during operation according to the mechanical parameters of the coaxial double crank plunger pump comprises: The connecting rod working displacement function of the connecting rod plunger connection during operation is determined based on the ratio of the crank radius to the connecting rod length, the connecting rod length, the movement angle between the crank limit position when the connecting rod moves to the maximum stroke and the crank movement position outside the crank limit position, and the sine function.

3. The method according to claim 2, characterized in that The expression of the connecting rod working displacement function is: Among them, S represents the connecting rod working displacement function, R represents the crank radius, x represents the movement angle, and L represents the connecting rod length.

4. The method according to claim 3, characterized in that The expression of the crank driving side angular velocity function is: ω Motor =V 设 *RE / (abs(S’(x))+abs(S’(x-D))); Among them, ω Motor Represents the angular velocity function of the crank drive side, 0.0 = <V 设 <0.0105m / s, V 设 represents the superimposed output speed of the piston, RE represents the gear ratio of the reducer, S'(x) represents the first-order derivative of the displacement, and D represents the arc difference of the motion position of the two cranks; The expression of the target angular velocity function is: ω M =V 设 *RE / (abs(S’(x-β))+abs(S’(x-D-β))); Among them, ω M represents the target angular velocity function, β represents the preset radian, π / 4≤β<5π / 18.

5. A PLC-based asymmetric coaxial double crank piston pump constant pressure motion control device, characterized in that: include: A first determination module is used to determine the connecting rod working displacement function of the connecting rod-plunger connection part during operation according to the mechanical parameters of the coaxial double crank plunger pump; wherein the mechanical parameters include: crank radius, connecting rod length, and movement angle between the crank limit position of the connecting rod moving to the maximum stroke and the crank movement position outside the crank limit position; A first calculation module is used to calculate the first-order derivative of the connecting rod working displacement function to obtain the first-order derivative of displacement; A second determination module is used to determine the crank driving side angular velocity function according to the superimposed output speed of the piston, the gear reduction ratio of the reducer, the arc difference of the motion positions of the two cranks and the first-order derivative of the displacement; A second calculation module is used to shift the crank driving side angular velocity function to the right by a preset arc to obtain a target angular velocity function; A setting module is used to use the target angular velocity function as the driving angular velocity function of the PLC controller; wherein the POS terminal of the PLC controller is used to input a signal for measuring the position of a mechanical crank, the TDC terminal is used to input a signal for measuring the reset origin of the mechanical crank, the 4-20mA current signal terminal is used to input a pressure signal for measuring the output end of the plunger pump, and the 4-20mA current output signal terminal is used to control the operating frequency of the inverter.

6. The device according to claim 5, characterized in that The method of determining the connecting rod working displacement function of the connecting rod-plunger connection portion during operation according to the mechanical parameters of the coaxial double crank plunger pump comprises: The connecting rod working displacement function of the connecting rod plunger connection during operation is determined based on the ratio of the crank radius to the connecting rod length, the connecting rod length, the movement angle between the crank limit position when the connecting rod moves to the maximum stroke and the crank movement position outside the crank limit position, and the sine function.

7. The device according to claim 6, characterized in that The expression of the connecting rod working displacement function is: Among them, S represents the connecting rod working displacement function, R represents the crank radius, x represents the movement angle, and L represents the connecting rod length.

8. The device according to claim 5, characterized in that The expression of the crank driving side angular velocity function is: ω Motor =V 设 *RE / (abs(S’(x))+abs(S’(x-D))); Among them, ω Motor Represents the angular velocity function of the crank drive side, 0.0 = <V 设 <0.0105m / s, V 设 represents the superimposed output speed of the piston, RE represents the gear ratio of the reducer, S'(x) represents the first-order derivative of the displacement, and D represents the arc difference of the motion position of the two cranks; The expression of the target angular velocity function is: ω M =V 设 *RE / (abs(S’(x-β))+abs(S’(x-D-β))); Among them, ω M represents the target angular velocity function, β represents the preset radian, π / 4≤β<5π / 18.

9. An electronic device comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, characterized in that: When the processor executes the program, the constant pressure motion control method of the coaxial double crank piston pump based on PLC as described in any one of claims 1 to 4 is implemented.

10. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the computer program is executed by a processor, the constant pressure motion control method of a coaxial double crank piston pump based on PLC according to any one of claims 1 to 4 is implemented.

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