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

Abstract

The application discloses a kind of constant pressure motion control methods of asymmetric coaxial double-crank plunger pump based on PLC, comprising the following steps: according to the mechanical parameters of coaxial double-crank plunger pump, determine the connecting rod working displacement function of connecting rod plunger connecting portion in working process;The first derivative of connecting rod working displacement function is calculated;Determine the angular velocity function of crank driving side according to the superimposed output speed of piston;The target angular velocity function is obtained by shifting the angular velocity function of crank driving side to right by preset radian;The target angular velocity function is used as the driving angular velocity function of PLC controller.The application controls driving motor to drive asymmetric double-crank plunger pump by the angular velocity function of crank driving side based on PLC controller, so that the superimposed speed of two pistons is constant, therefore, the fluid flow output by plunger pump is constant, the pressure of pump outlet is also constant, and the requirement of constant fluid flow of automobile spraying process can be met.

Description

Technical Field

[0001] This invention relates to the field of computer control technology, and in particular to a PLC-based constant pressure motion control method and device for a coaxial double crank piston pump. Background Technology

[0002] The existing ACS module's PCB is developed using a single-board computer and features digital I / O, AD, and DA interfaces, packaged in an aluminum profile casing. The ACS module controls the coaxial double-crank piston pump to rotate from the origin. Based on the position changes of the asymmetric double crank, the ACS module outputs different 4-20mA analog current values ​​to precisely adjust the speed of the frequency converter, thereby controlling the pump outlet to maintain a constant pressure.

[0003] Because the ACS-controlled electric pump exhibits significant pressure fluctuations at the pump outlet, failing to provide fluids suitable for automotive painting processes, and requiring replacement with a completely new ACS controller to alleviate the pressure fluctuation problem, the replacement cost is high. Furthermore, the ACS PCB is developed using a microcontroller; oscilloscope measurements and analysis of its electronic circuit structure revealed relatively weak anti-interference capabilities, with substantial high-frequency noise detected entering the microcontroller on digital pins. Additionally, the ACS control program is not open-source, preventing users and integrators from flexibly modifying it. When the ACS control system malfunctions, online monitoring and code modification are impossible, resulting in prolonged equipment repair and production recovery times and high replacement and repair costs. Moreover, the ACS single-board computer is geared towards electronic engineering, requiring electronic engineers to possess extensive electronic knowledge and microcontroller programming skills, increasing the difficulty for electrical personnel in diagnosing and troubleshooting electronic faults. Summary of the Invention

[0004] To address the aforementioned problems in the existing technology, this invention provides a PLC-based constant pressure motion control method, device, electronic equipment, and storage medium for a coaxial double-crank piston pump. The technical problem to be solved by this invention is achieved through the following technical solution:

[0005] The first aspect of this invention provides a PLC-based constant pressure motion control method for a coaxial dual-crank piston pump, comprising the following steps:

[0006] Based on the mechanical parameters of the coaxial dual-crank piston pump, determine the working displacement function of the connecting rod at the connecting rod piston connection during operation; wherein, the mechanical parameters include: crank radius, connecting rod length, and the motion angle between the crank limit position when the connecting rod moves to its maximum stroke and the crank movement position other than the crank limit position;

[0007] The first derivative of the working displacement function of the connecting rod is calculated to obtain the first derivative of the displacement.

[0008] The crank drive side angular velocity function is determined based on the piston superposition output speed, the gear reduction ratio of the reducer, the difference in the arc of the two crank positions, and the first derivative of the displacement.

[0009] The crank drive side angular velocity function is shifted to the right by a preset radian to obtain the 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 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 at the output end of the piston 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 during operation based on the mechanical parameters of the coaxial double crank piston pump includes:

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

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

[0014]

[0015] Where S represents the working displacement function of the connecting rod, R represents the crank radius, x represents the motion angle, and L represents the length of the connecting rod.

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

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

[0018] Where, ω Motor Represents the crank-drive side angular velocity function, 0.0 = <V 设 <0.0105m / s, V 设 The output speed of the piston superposition is represented by RE, the gear reduction ratio of the reducer is represented by S'(x), the first derivative of the displacement is represented by D, and the difference in the radian of the two crank positions is represented by D.

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

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

[0021] Where, ω M Let β represent the target angular velocity function, β represent the preset radians, and π / 4 ≤ β < 5π / 18.

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

[0023] The first determining module is used to determine the working displacement function of the connecting rod of the connecting rod plunger connection during operation based on the mechanical parameters of the coaxial dual crank plunger pump; wherein the mechanical parameters include: crank radius, connecting rod length, and motion angle between the crank limit position when the connecting rod moves to the maximum stroke and the crank movement position other than the crank limit position;

[0024] The first calculation module is used to calculate the first derivative of the working displacement function of the connecting rod to obtain the first derivative of the displacement.

[0025] The second determining module is used to determine the crank drive side angular velocity function based on the piston superimposed output speed, the gear reduction ratio of the reducer, the difference in the arc of the two crank positions, and the first derivative of the displacement.

[0026] The second calculation module is used to shift the crank drive side angular velocity function to the right by a preset radian to obtain the target angular velocity function;

[0027] The 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 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 at the output end of the piston pump, and the 4-20mA current output signal terminal is used to control the operating frequency of the frequency converter.

[0028] In one embodiment of the present invention, determining the connecting rod working displacement function of the connecting rod plunger connection during operation based on the mechanical parameters of the coaxial double crank piston pump includes:

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

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

[0031]

[0032] Where S represents the working displacement function of the connecting rod, R represents the crank radius, x represents the motion angle, and L represents the length of the connecting rod.

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

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

[0035] Where, ω Motor Represents the crank-drive side angular velocity function, 0.0 = <V 设 <0.0105m / s, V 设 The output speed of the piston superposition is represented by RE, the gear reduction ratio of the reducer is represented by S'(x), the first derivative of the displacement is represented by D, and the difference in the radian of the two crank positions is represented by D.

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

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

[0038] Where, ω M Let β represent the target angular velocity function, β represent the preset radians, and π / 4 ≤ β < 5π / 18.

[0039] A third aspect 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, it implements a PLC-based constant pressure motion control method for a coaxial dual-crank piston pump provided in the first aspect of the present invention.

[0040] A fourth aspect of the present invention provides a computer-readable storage medium having a computer program stored thereon, wherein the computer program, when executed by a processor, implements a PLC-based constant pressure motion control method for a coaxial double crank piston pump provided in the first aspect of the present invention.

[0041] The beneficial effects of this invention are:

[0042] This invention utilizes a PLC controller to control the drive motor of an asymmetric double-crank piston pump via a crank-driven angular velocity function. This ensures a constant superimposed velocity of the two pistons, resulting in a constant fluid flow rate and consequently a constant pump outlet pressure, meeting the constant fluid flow requirements of automotive painting processes. Furthermore, the PLC-based controller enhances the anti-interference capability of the constant-pressure motion control electrical system for the asymmetric double-crank piston pump. Simultaneously, the PLC-based control code can be independently developed, reducing the difficulty of monitoring, modifying, and querying code information, enabling rapid and immediate fault location, and minimizing time and parts costs during repair. Moreover, the PLC controller facilitates fault diagnosis and troubleshooting for operators. Therefore, this PLC-based constant-pressure motion controller for the asymmetric double-crank piston pump significantly reduces production costs for automotive companies in the painting sector, while also expanding the operational capabilities of electrical engineers in maintenance and repair.

[0043] Other features and advantages of the invention will be set forth in the description which follows, and will be apparent in part from the description, or may be learned by practicing the invention. The objects and other advantages of the invention may be realized and obtained by means of the structures particularly pointed out in the written description, claims, and drawings.

[0044] The technical solution of the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. Attached Figure Description

[0045] The accompanying drawings are provided to further illustrate the invention and form part of the specification. They are used in conjunction with embodiments of the invention to explain the invention and do not constitute a limitation thereof. In the drawings:

[0046] Figure 1 A flowchart illustrating a PLC-based constant pressure motion control method for a coaxial dual-crank piston pump, provided for an embodiment of the present invention;

[0047] Figure 2a A schematic diagram of the initial position of the crank and connecting rod, showing the working displacement function of the connecting rod, provided in 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 moves by an angle α, as provided in an embodiment of the present invention.

[0049] Figure 2c This is a schematic diagram of the preset arc degree of crank position angle offset provided in an embodiment of the present invention;

[0050] Figure 3 The following is a Matlab simulation diagram of the crank drive side angular velocity function provided in an embodiment of the present invention;

[0051] Figure 4 The crank drive side angular velocity function provided in this embodiment of the invention is a function image obtained by programming in CAD.

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

[0053] Figure 6 This is a schematic diagram of an electronic cam function image for real-time tracking of motor angular velocity versus angle under flow mode, provided in an embodiment of the present invention.

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

[0055] Figure 8 This is a schematic diagram of the velocity curves of the two pistons of an asymmetric coaxial double crank plunger modeled by ODEK Inventor for uniform motion simulation in an embodiment of the present invention.

[0056] Figure 9 Provided for embodiments of the present invention Figure 8 A schematic diagram of the superimposed velocity image obtained by taking the absolute values ​​of piston velocities V[1] and V[2] and summing them;

[0057] Figure 10 This is a block diagram of a PLC-based coaxial dual-crank piston pump constant pressure motion controller provided for an embodiment of the present invention. Detailed Implementation

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

[0059] like Figure 1 As shown, the first aspect of this invention provides a PLC-based constant pressure motion control method for a coaxial dual-crank piston pump, comprising the following steps:

[0060] Step 11: Based on the mechanical parameters of the coaxial double crank piston pump, determine the connecting rod working displacement function of the connecting rod piston connection during operation.

[0061] The mechanical parameters include: crank radius, connecting rod length, and the angle of motion between the crank limit position when the connecting rod moves to its maximum stroke and the crank movement position other than the crank limit position.

[0062] Step 12: Calculate the first derivative of the working displacement function of the connecting rod to obtain the first derivative of the displacement.

[0063] Step 13: Determine the crank drive side angular velocity function based on the piston superimposed output speed, the gear reduction ratio of the reducer, the difference in the arc of the two crank positions, and the first derivative of the displacement.

[0064] Step 14: Shift the crank drive side angular velocity function to the right by a preset radian to obtain the 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 point of the mechanical crank, the 4-20mA current signal terminal is used to input the pressure signal at the output end of the piston pump, and the 4-20mA current output signal terminal is used to control the operating frequency of the frequency converter.

[0067] In this embodiment, the asymmetric double-crank piston pump is driven by a drive motor controlled by a PLC controller using the crank-driven side angular velocity function. This ensures a constant superimposed velocity of the two pistons, resulting in a constant fluid flow rate and consequently a constant pump outlet pressure, meeting the constant fluid flow rate requirement of automotive painting processes. Furthermore, the PLC controller improves the anti-interference capability of the constant-pressure motion control electrical system for the asymmetric double-crank piston pump. Simultaneously, the control code based on the PLC controller can be independently developed, reducing the difficulty of monitoring, modifying, and querying code information, enabling rapid and immediate fault location, and relatively lower time and parts costs during maintenance. In addition, the PLC controller facilitates fault diagnosis and troubleshooting for personnel. Therefore, the PLC-based constant-pressure motion controller for the asymmetric double-crank piston pump significantly reduces production costs for automotive companies in the painting sector, while also expanding the operational capabilities of electrical engineers in maintenance and upkeep.

[0068] A second aspect of this invention provides a PLC-based constant pressure motion control method for a coaxial dual-crank piston pump, comprising the following steps:

[0069] Step 21: Based on the mechanical parameters of the coaxial double crank piston pump, determine the connecting rod working displacement function of the connecting rod piston connection during operation.

[0070] The mechanical parameters include: crank radius, connecting rod length, and the angle of motion between the crank limit position when the connecting rod moves to its maximum stroke and the crank movement position other than the crank limit position.

[0071] In this embodiment, the asymmetric double-crank plunger pump uses an asynchronous motor as the prime mover, which is powered by a frequency converter. The reducer and crank are designed as an integral mechanical mechanism, and the crank and connecting rod form a rotating pair. Ultimately, the connecting rod drives the piston of the asymmetric double-crank plunger pump to move vertically. 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 move up and down reciprocally.

[0072] The PLC controller's POS terminal is used to input the signal for measuring the position of the mechanical crank (i.e., the arc of the crank's movement). 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's movement calculated from 0 after the sensor detects this reset origin. The 4-20mA current signal terminal is used to input the pressure signal at the output of the plunger pump, and the 4-20mA current output signal terminal is used to control the operating frequency of the frequency converter.

[0073] The specific steps of this process are as follows: Based on the ratio of crank radius to connecting rod length, connecting rod length, the motion angle between the crank limit position (when the connecting rod moves to its maximum stroke) and the crank position outside the limit position, and a sine function, determine the connecting rod working displacement function of the connecting rod plunger connection during operation. The expression for the connecting rod working displacement function is:

[0074]

[0075] Where S represents the working displacement function of the connecting rod, R represents the crank radius, x represents the motion angle, and L represents the length of the connecting rod.

[0076] Here, for example, such as Figure 2a and Figure 2b As shown, the crank radius R is 0.06m (lengths of OA and OE), the connecting rod length L is 0.35m, the gear reduction ratio is 75.16:1 (generally taken as an integer), the two crank angles differ by 78° (asymmetrical), and the motion angle x = ∠AOB between the crank limit position A (when the connecting rod moves upward to its maximum stroke) and the crank motion position B (which can also be considered as the initial position of the function model). That is, the crank's motion trajectory (the motion trajectory of the connection between the crank and connecting rod is simplified as the crank's motion trajectory) is a circle with center O and radius R. When the connecting rod moves upward to its maximum stroke, the crank is at position A. During operation, the crank moves from A to a certain position B, that is, after x moves by an angle 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, calculated based on the trigonometric function relationships of a triangle. The connecting rod plunger connection is the connection between the connecting rod and the plunger.

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

[0078]

[0079] Step 22: Calculate the first derivative of the working displacement function of the connecting rod to obtain the first derivative of the displacement.

[0080] For example, with a crank radius R of 0.06m (lengths OA and OE), a connecting rod length L of 0.35m, a gear reduction ratio of 75.16:1 (generally taken as an integer), and the first derivative of the connecting rod displacement function when the included angle between the two cranks is 78° (39π / 90 radians), the following is given:

[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: Determine the crank drive side angular velocity function based on the piston superimposed output speed, the gear reduction ratio of the reducer, the difference in the arc of the two crank positions, and the first derivative of the displacement.

[0083] Here, the combined piston output speed is the sum of the absolute values ​​of the output speeds of the two pistons corresponding to the two cranks. This combined piston output speed can be set as needed. Assuming the piston moves vertically, the combined piston output speed is V. 设 Since the piston in the plunger pump does work during both its rising and falling phases, taking the absolute value of the first derivative and considering the angle difference between the two cranks, the expression for the crank drive side angular velocity function is:

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

[0085] Where, ω Motor Represents the crank-drive side angular velocity function, 0.0 = <V 设 <0.0105m / s, V 设 denoted by , RE represents the gear reduction ratio of the reducer, S'(x) represents the first derivative of the displacement, and D represents the difference in the radian of the two crank positions.

[0086] For example, the expression for the crank drive side angular velocity function, which takes into account the gear reduction ratio of the reducer and the difference in the radian of the two cranks' positions, is: ω Motor =V 设 *75 / (abs(S'(x))+abs(S'(x-39π / 90))), the image generated by this formula in Matlab is 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 Since the images have the same shape, both Matlab and AutoCAD programming methods can verify the correctness of the function graphs.

[0087] Step 24: Shift the crank drive-side angular velocity function to the right by a preset radian to obtain the target angular velocity function. The above-mentioned crank drive-side angular velocity function is a function under ideal conditions; however, in practical applications, the crank's position angle may deviate to some extent, such as... Figure 2c As shown, the ideal position of the crank is at point A, but at that moment the actual position of the crank is at point B, a difference of β radians. Position E is the position of another crank. Therefore, after shifting the crank drive side angular velocity function to the right by β radians, the expression for the target angular velocity function is:

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

[0089] Where, ω M Let β represent the target angular velocity function, β represent the preset radians, and π / 4 ≤ β < 5π / 18.

[0090] For example, substituting the values ​​of the aforementioned mechanical parameters, and with β = π / 4, the expression for the target angular velocity function is: ω M =V 设 *75 / (abs(S'(x-π / 4))+abs(S'(x-33π / 180))) This formula generates a phase-shifting function graph in Matlab as follows: Figure 5 As shown.

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

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

[0093] In this embodiment, the feasibility of the target angular velocity function is illustrated using PLC+UG / NX combined virtual motion simulation technology. The simulated mechanical parameters use the values ​​of the aforementioned mechanical parameters. For example... Figure 7 As shown, the top red line represents the input angular velocity using the target angular velocity function, while the bottom red line represents the superimposed velocity of "Piston 1" and "Piston 2," which is a constant value. According to fluid mechanics principles, since the superimposed velocity of the two pistons is constant, the pump's output fluid flow rate is constant, and therefore the pump outlet pressure is also constant. Simultaneously, theoretical uniform motion simulation was performed using ODEK Inventor modeling. During the simulation, a cam was used to drive an asymmetric coaxial double-crank piston at a constant speed, resulting in the velocity curves of the two pistons as shown below. Figure 8 As shown, Figure 8 The absolute values ​​of the piston velocities V[1] and V[2] are taken and summed to obtain the following: Figure 9 From the image, we can see that... Figure 5 and Figure 9 The image shapes are symmetrical about the horizontal axis, forming a completely complementary situation. Therefore, the result of adding the two is constant and can meet the production requirements of constant pressure.

[0094] like Figure 10 As shown, a third aspect of the present invention provides a PLC-based constant pressure motion control device for an asymmetric coaxial dual-crank piston pump, comprising:

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

[0096] The first calculation module 32 is used to calculate the first derivative of the working displacement function of the connecting rod to obtain the first derivative of the displacement.

[0097] The second determining module 33 is used to determine the crank drive side angular velocity function based on the piston superimposed output speed, the gear reduction ratio of the reducer, the difference in the arc of the two crank positions and the first derivative of the displacement.

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

[0099] The setting module 35 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 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 at the output end of the piston pump, and the 4-20mA current output signal terminal is used to control the operating frequency of the frequency converter.

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

[0101] Based on the ratio of crank radius to connecting rod length, connecting rod length, the motion angle and sine function between the crank limit position when the connecting rod moves to its maximum stroke and the crank position other than the crank limit position, determine the connecting rod working displacement function of the connecting rod plunger connection during operation.

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

[0103]

[0104] Where S represents the working displacement function of the connecting rod, R represents the crank radius, x represents the motion angle, and L represents the length of the connecting rod.

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

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

[0107] Where, ω Motor Represents the crank-drive side angular velocity function, 0.0 = <V 设 <0.0105m / s, V 设 The output speed of the piston superposition is represented by RE, the gear reduction ratio of the reducer is represented by S'(x), the first derivative of the displacement is represented by D, and the difference in the radian of the two crank positions is represented by D.

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

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

[0110] Where, ω MLet β represent the target angular velocity function, β represent the preset radians, and π / 4 ≤ β < 5π / 18.

[0111] A fourth aspect 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, it implements the constant pressure motion control method for a coaxial double crank piston pump based on a PLC provided in the present invention.

[0112] The fifth aspect of this invention also provides a computer-readable storage medium storing a computer program thereon, which, when executed by a processor, implements the steps of the PLC-based constant pressure motion control method for a coaxial double crank piston pump provided in the above-described embodiments of this invention.

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

[0114] The processors mentioned above can be general-purpose processors, including central processing units (CPUs), network processors (NPs), etc.; they can also be digital signal processors (DSPs), application-specific integrated circuits (ASICs), field-programmable gate arrays (FPGAs), or other programmable logic devices, discrete gate or transistor logic devices, or discrete hardware systems.

[0115] The method provided in this invention can be applied to electronic devices. Specifically, the electronic device can be a desktop computer, a portable computer, a smart mobile terminal, a server, etc. No limitation is made herein; any electronic device that can implement this invention falls within the protection scope of this invention.

[0116] For the device / electronic device embodiments, since they are basically similar to the method embodiments, the description is relatively simple, and relevant parts can be referred to in the description of the method embodiments.

[0117] This invention is described with reference to flowchart illustrations and / or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of the invention. It will be understood that each block of the flowchart illustrations and / or block diagrams, and combinations of blocks in the flowchart illustrations and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, special-purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, generate instructions for implementing the flowchart illustrations and / or block diagrams. Figure 1 One or more processes and / or boxes Figure 1 A device that provides the functions specified in one or more boxes.

[0118] These computer program instructions may also be stored in a computer-readable storage medium that can direct a computer or other programmable data processing device to function in a particular manner, such that the instructions stored in the computer-readable storage medium produce an article of manufacture including instruction means, which are implemented in a process Figure 1 One or more processes and / or boxes Figure 1 The function specified in one or more boxes.

[0119] These computer program instructions may also be loaded onto a computer or other programmable data processing equipment to cause a series of operational steps to be performed on the computer or other programmable equipment to produce a computer-implemented process, thereby providing instructions that execute on the computer or other programmable equipment for implementing the process. Figure 1 One or more processes and / or boxes Figure 1 The steps of the function specified in one or more boxes.

[0120] Obviously, those skilled in the art can make various modifications and variations to this invention without departing from its spirit and scope. Therefore, if these modifications and variations fall within the scope of the claims of this invention and their equivalents, this invention also intends to include these modifications and variations.

Claims

1. A PLC-based constant pressure motion control method for a coaxial double-crank piston pump, characterized in that, Includes the following steps: Based on the mechanical parameters of the coaxial dual-crank piston pump, determine the working displacement function of the connecting rod at the connecting rod piston connection during operation; wherein, the mechanical parameters include: crank radius, connecting rod length, and the motion angle between the crank limit position when the connecting rod moves to its maximum stroke and the crank movement position other than the crank limit position; The first derivative of the working displacement function of the connecting rod is calculated to obtain the first derivative of the displacement. The crank drive side angular velocity function is determined based on the piston superposition output speed, the gear reduction ratio of the reducer, the difference in the arc of the two crank positions, and the first derivative of the displacement. The crank drive side angular velocity function is shifted to the right by a preset radian to obtain the 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 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 at the output end of the piston pump, and the 4-20mA current output signal terminal is used to control the operating frequency of the frequency converter. The determination of the connecting rod working displacement function of the connecting rod plunger connection during operation, based on the mechanical parameters of the coaxial double crank piston pump, includes: Based on the ratio of crank radius to connecting rod length, connecting rod length, the motion angle and sine function between the crank limit position when the connecting rod moves to its maximum stroke and the crank movement position other than the crank limit position, determine the connecting rod working displacement function of the connecting rod plunger connection during operation; The expression for the working displacement function of the connecting rod is: Where S represents the working displacement function of the connecting rod, R represents the crank radius, x represents the motion angle, and L represents the length of the connecting rod; The expression for the crank-driven side angular velocity function is: ω Motor =V 设 *RE / (abs(S’(x))+abs(S’(x-D))); Where, ω Motor Represents the crank-driven side angular velocity function, 0≤V 设 <0.0105m / s, V 设 The output speed of the piston superposition is represented by RE, the gear reduction ratio of the reducer is represented by S'(x), the first derivative of the displacement is represented by D, and the difference in the radian of the two crank positions is represented by D. The expression for the target angular velocity function is: ω M =V 设 *RE / (abs(S’(x-β))+abs(S’(x-D-β))); Where, ω M Let β represent the target angular velocity function, β represent the preset radians, and π / 4 ≤ β < 5π / 18.

2. A PLC-based constant pressure motion control device for a coaxial double-crank piston pump, characterized in that, include: The first determining module is used to determine the working displacement function of the connecting rod of the connecting rod plunger connection during operation based on the mechanical parameters of the coaxial dual crank plunger pump; wherein the mechanical parameters include: crank radius, connecting rod length, and motion angle between the crank limit position when the connecting rod moves to the maximum stroke and the crank movement position other than the crank limit position; The first calculation module is used to calculate the first derivative of the working displacement function of the connecting rod to obtain the first derivative of the displacement. The second determining module is used to determine the crank drive side angular velocity function based on the piston superimposed output speed, the gear reduction ratio of the reducer, the difference in the arc of the two crank positions, and the first derivative of the displacement. The second calculation module is used to shift the crank drive side angular velocity function to the right by a preset radian to obtain the target angular velocity function; The 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 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 at the output end of the piston pump, and the 4-20mA current output signal terminal is used to control the operating frequency of the frequency converter. The determination of the connecting rod working displacement function of the connecting rod plunger connection during operation, based on the mechanical parameters of the coaxial double crank piston pump, includes: Based on the ratio of crank radius to connecting rod length, connecting rod length, the motion angle and sine function between the crank limit position when the connecting rod moves to its maximum stroke and the crank movement position other than the crank limit position, determine the connecting rod working displacement function of the connecting rod plunger connection during operation; The expression for the working displacement function of the connecting rod is: Where S represents the working displacement function of the connecting rod, R represents the crank radius, x represents the motion angle, and L represents the length of the connecting rod; The expression for the crank-driven side angular velocity function is: ω Motor =V 设 *RE / (abs(S’(x))+abs(S’(x-D))); Where, ω Motor Represents the crank-driven side angular velocity function, 0≤V 设 <0.0105m / s, V 设 The output speed of the piston superposition is represented by RE, the gear reduction ratio of the reducer is represented by S'(x), the first derivative of the displacement is represented by D, and the difference in the radian of the two crank positions is represented by D. The expression for the target angular velocity function is: ω M =V 设 *RE / (abs(S’(x-β))+abs(S’(x-D-β))); Where, ω M Let β represent the target angular velocity function, β represent the preset radians, and π / 4 ≤ β < 5π / 18.

3. 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 computer program, it implements the constant pressure motion control method for a coaxial double crank piston pump based on PLC as described in claim 1.

4. A computer-readable storage medium having a computer program stored thereon, characterized in that, When the computer program is executed by the processor, it implements the constant pressure motion control method for a coaxial double crank piston pump based on PLC as described in claim 1.

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