A basic flow control method based on full-electric-controlled positive flow excavator

Abstract

The application discloses a basic flow control method based on a full-electric-control positive flow excavator, controls a main pump, sets corresponding engine rotating speed, controls the maximum theoretical flow of the main pump, controls the displacement of the main pump through a proportional electromagnetic valve corresponding to the current of a pilot handle, provides required flow for a hydraulic cylinder, and further controls a working device. In the working process, the current of the proportional electromagnetic valve of the main pump changes with the pilot handle, and when the current reaches the maximum value, the flow reaches the maximum value. In each part of the working cycle, the action is set with a priority relationship, in each part of the loading process, each electric control valve core is prior to flow distribution algorithm control each action flow, the excavator electro-hydraulic system is cooperatively controlled, the working device and the special device of the excavator are accurately controlled, the development efficiency of the whole machine is accelerated, the product development time is shortened, and the function of meeting the different tonnage and special configuration requirements of the excavator is achieved.

Description

Technical Field

[0001] This invention relates to the field of excavator technology, specifically a basic flow control method based on a fully electronically controlled positive flow excavator. Background Technology

[0002] With the continuous development of industries such as landscaping, construction, and mining, the demand for excavators of different types, working conditions, and configurations is increasing. In addition to factors such as fuel consumption, efficiency, smoothness, and maneuverability, new requirements are being placed on the variety of products and the speed of development. Highly efficient, flexible, and reliable positive flow hydraulic systems, combined with highly accurate and fast-response electronically controlled multi-way valves, can better meet the various needs of users. This has also increased the difficulty of developing corresponding control methods.

[0003] The main research direction at present is to accelerate the development of control algorithms for excavators with various configurations, meet the needs of different working conditions, rationally distribute hydraulic oil in various actuators of the excavator, improve the overall maneuverability and accuracy of the vehicle, and at the same time meet the speed requirements of various working devices.

[0004] Therefore, the inventors sought to solve the problem of designing a device for coordinated control between the electro-hydraulic systems of an excavator, precise control of the excavator's working devices and special devices, thereby accelerating the overall machine development efficiency, shortening product development time, and meeting the needs of excavators with different tonnages and special configurations. Summary of the Invention

[0005] To address the shortcomings of existing technologies, the purpose of this invention is to provide a basic flow control method for fully electronically controlled positive flow excavators. This method enables coordinated control between the excavator's electro-hydraulic systems and precise control of the excavator's working devices and special devices, thereby accelerating overall machine development efficiency, shortening product development time, and meeting the functional requirements of excavators with different tonnages and special configurations.

[0006] The technical solution adopted by the device of this invention is: a basic flow control method based on a fully electronically controlled positive flow excavator, which includes the following steps:

[0007] (1) Control the main pump and set the corresponding engine speed;

[0008] (2) Control the theoretical maximum flow of the engine main pump by controlling the proportional solenoid valve through the corresponding current control of the pilot handle to control the displacement of the main pump;

[0009] (3) To provide the required flow rate to the hydraulic cylinder, thereby controlling the working device;

[0010] (4) During operation, the current of the main pump proportional solenoid valve changes with the pilot handle. When the current reaches its maximum value, the flow rate reaches its maximum.

[0011] (5) The priority relationship of each part of the work cycle is set, and the priority and flow distribution algorithm of each electronically controlled valve core in each part of the loading process controls the flow of each action.

[0012] Furthermore, the control of the main pump in step (1) includes developing personalized operation control strategies based on the operator's habits and working conditions. By learning the operator's operating habits, the controller automatically adjusts the flow distribution so that the excavator can achieve the best performance under different working conditions.

[0013] Furthermore, the hydraulic cylinder in step (3) adopts a flow-compensated directional valve, including a main throttle valve and a flow supplement valve, to achieve more precise flow distribution.

[0014] Furthermore, it also includes step (6) using advanced modeling and simulation technology to perform detailed modeling of the hydraulic system, and by simulating the system behavior under different working conditions, to identify performance bottlenecks and potential fault points in advance, and to optimize the system design.

[0015] Furthermore, in step (5), the priority relationship is that the bucket stick has priority during excavation.

[0016] The beneficial effects of the device of the present invention are:

[0017] 1. This invention provides a basic flow control method for a fully electronically controlled positive flow excavator. The method utilizes an electro-proportional hydraulic pump and an electronically controlled multi-way valve, along with the main valve opening characteristics and system pressure collected by a pressure sensor, to achieve coordinated control between the excavator's electro-hydraulic systems. Furthermore, it provides a basic control platform for different application scenarios and excavator configurations based on parameters of various hydraulic components, actuators, and working devices. This platform allows for multiple development iterations, accelerating the development efficiency of various configuration control methods and improving the standardization level of excavator control methods. Detailed Implementation

[0018] The apparatus of the present invention will be further described below with reference to specific embodiments. These embodiments are for illustrative purposes only and are not intended to limit the scope of the invention. Furthermore, it should be understood that after reading the teachings of the apparatus of the present invention, those skilled in the art can make various alterations or modifications to the invention, and these equivalent forms also fall within the scope defined by the appended claims.

[0019] Example 1: When the load on the actuator changes, the flow compensation valve can automatically adjust the flow according to the controller's instructions to ensure that the flow demand of the actuator is met. This compensation mechanism can effectively solve the problem of insufficient flow caused by load changes in traditional systems and improve the system's response speed and stability.

[0020] The main pump is controlled. When the excavator is not under load, the engine speed in each gear is fixed. The engine drives the main pump, and the proportional solenoid valve is controlled by the corresponding current through the pilot handle to control the displacement of the main pump, so as to provide the required flow to the hydraulic cylinder and thus control the working device.

[0021] To reduce energy loss caused by excessive engine power, the maximum power for each gear needs to be set, and the required flow rate is calculated using the main pump pressure sensor. The formula is as follows:

[0022] W=PQ

[0023] In the formula, W represents power; P represents pressure; and Q represents flow rate.

[0024] The flow rate is related to the main pump speed and displacement, that is:

[0025] Q=nq

[0026] In the formula, n is the main pump speed; q is the main pump displacement.

[0027] The main pump's displacement is controlled by adjusting the proportional solenoid valve, using the following formula:

[0028] q = f(I)

[0029] In the formula, I is the control current; f(I) is a function of current and displacement.

[0030] Except for the pressure, which is obtained in real time from the sensor, all other variables are inherent properties of the main pump and can be replaced or changed as needed.

[0031] The working pressure of an excavator is determined by the external load, and the speed of the working device is limited by the flow rate. Therefore, flow distribution, i.e., the control of the main valve, is the core of the control method. Based on loading operations, the excavator's working cycle can be divided into four parts: digging, slewing, loading, and resetting. The working devices cooperate with each other in each part. Digging mainly involves the retraction of the stick and bucket, combined with boom lifting. The slewing part includes slewing, boom lifting, and the retraction of the stick and bucket to prevent material from falling. The unloading action includes slewing, the outward tilting of the stick, the outward tilting of the bucket, and the lowering of the boom. Finally, the excavator's working device resets, and digging starts again, with actions including slewing, lowering the boom, retraction of the stick, and retraction of the bucket. Ideally, loading can be simply divided, but in actual operation, the working conditions are complex, and the actions are more arbitrary. Therefore, the resetting is divided by the working device, i.e., the retraction and outward tilting are not distinguished.

[0032] During operation, the excavator's speed is constant in each gear. The current of the main pump proportional solenoid valve changes with the pilot handle. When the current reaches its maximum value, the main pump swashplate angle reaches its maximum, which means the displacement is at its maximum. At this time, the flow rate is at its maximum. To ensure smooth operation of each working device, priority relationships need to be set for the actions in each part of the work cycle. Among them, digging is mainly driven by the stick, slewing is mainly driven by the boom and slewing, unloading is mainly driven by the stick and bucket, and reset is distributed proportionally.

[0033] Meanwhile, the flow rate is affected by the multi-way valve core. A pilot threshold is set to determine the degree of action execution and to define the current cycle range. During mining:

[0034] AmIn1 + X1BmUp2 + xBcIn2 = C1

[0035] AmIn2+X2BmUp1+xBcIn1=C2

[0036] Among them, AmIn1 and AmIn2 are the preset current values ​​of the boom retraction valve cores 1 and 2 corresponding to the pilot handle; xBcIn1 and xBcIn2 are the calculated current values ​​of the bucket retraction valve cores 1 and 2, which must be the smaller of the preset values ​​before use; BmUp1 and BmUp2 are the preset current values ​​of the boom rise valve cores 1 and 2 corresponding to the pilot handle; C1 and C2 are the total current of the valve core opening during the digging process, which is determined by the pilot pressure and the main pump flow rate; X1 and X2 are the digging limit constants of the boom valve cores, which are affected by factors such as the handle opening and action priority.

[0037] Similarly, during the slewing process:

[0038] BmUp1+Y1AmIn2+xBcIn1=D1

[0039] BmUp2+Y2AmIn1+xBcIn2+Z1Sw=D2

[0040] Among them, Y1 and Y2 are the boom valve core rotation restriction constants, which are affected by factors such as handle opening degree and action priority; Sw is the preset value of rotation current; Z1 is the boom priority constant relative to rotation; D1 and D2 are the total current of valve core opening during rotation, which are determined by pilot pressure and main pump flow rate.

[0041] The unloading process includes:

[0042] Am1 + X3Bm2 + xBcOut2 + Z1Sw = E1

[0043] Am2 + X4Bm1 + xBcOut1 = E2

[0044] Among them, Am1 and Am2 are the preset current values ​​of boom valve cores 1 and 2 corresponding to the pilot handle; X3 and X4 are the unloading limit constants of the boom valve core, which are affected by factors such as handle opening and action priority; Bm1 and Bm2 are the preset current values ​​of boom valve cores 1 and 2 corresponding to the pilot handle; xBcOut1 and xBcOut2 are the calculated current values ​​of bucket tilting valve cores 1 and 2, which need to be smaller than the preset values ​​before use; E1 and E2 are the total current of valve core opening during the unloading process, which are determined by the pilot pressure and main pump flow rate.

[0045] The resetting process after unloading includes:

[0046] BmDn1+Am2+xBcIn1=F1

[0047] BmDn2+Am1+xBcIn2+Sw=F2

[0048] Among them, BmDn1 and BmDn2 are the valve core currents corresponding to the boom descent pilot; F1 and F2 are the total valve core opening currents during the reset process, which are determined by the pilot pressure and the main pump flow rate.

[0049] This invention provides a basic flow control method for a fully electronically controlled positive flow excavator. The method utilizes an electro-proportional hydraulic pump and an electronically controlled multi-way valve, along with the main valve opening characteristics and system pressure collected by a pressure sensor, to achieve coordinated control between the excavator's electro-hydraulic systems. Furthermore, it provides a basic control platform for different application scenarios and excavator configurations based on parameters of various hydraulic components, actuators, and working devices. This platform allows for multiple development iterations, accelerating the development efficiency of various configuration control methods and improving the standardization level of excavator control methods.

Claims

1. A basic flow control method based on a fully electronically controlled positive flow excavator, comprising the following steps: Set the engine speed for each gear, and the engine drives the main pump; The current of the proportional solenoid valve is controlled by the pilot handle to control the main pump displacement, provide the required flow to the hydraulic cylinder, and thus control the working device. During operation, the current of the main pump proportional solenoid valve changes with the pilot handle. When the current reaches its maximum value, the main pump flow rate reaches its maximum. The working cycle of the excavator is divided into four parts: digging, slewing, unloading, and resetting. Priority relationships and flow distribution strategies are set for each part. Among them, digging is mainly based on the stick, slewing is mainly based on the boom and slewing, unloading is mainly based on the stick and bucket, and resetting is distributed proportionally. The following distribution formula is used for the traffic during the mining phase: AmIn1 + X1BmUp2 + xBcIn2 = C1 AmIn2+X2BmUp1+xBcIn1=C2 Among them, AmIn1 and AmIn2 are the preset current values ​​of the first and second boom retraction valve cores corresponding to the pilot handle; xBcIn1 and xBcIn2 are the calculated current values ​​of the valve cores for the first and second bucket retraction, which must be smaller than the preset values ​​before use; BmUp1 and BmUp2 are the preset current values ​​of the first and second boom raising valve cores corresponding to the pilot handle; C1 and C2 are the total current of the valve core opening during the digging process, which is determined by the pilot pressure and the main pump flow rate; X1 and X2 are the boom valve core digging limit constants, which are affected by the handle opening and action priority. The flow rate during the slewing phase is allocated using the following formula: BmUp1+Y1AmIn2+xBcIn1=D1 BmUp2+Y2AmIn1+xBcIn2+Z1Sw=D2 Among them, Y1 and Y2 are the boom valve core rotation limitation constants, which are affected by the handle opening and action priority; Sw is the preset value of rotation current; Z1 is the boom priority constant relative to rotation; D1 and D2 are the total current of valve core opening during rotation, which are determined by pilot pressure and main pump flow. The flow rate during the unloading stage is distributed using the following formula: Am1 + X3Bm2 + xBcOut2 + Z1Sw = E1 Am2 + X4Bm1 + xBcOut1 = E2 Among them, Am1 and Am2 are the preset current values ​​of the first and second boom valve cores corresponding to the pilot handle; X3 and X4 are the unloading limit constants of the boom valve core, which are affected by factors such as handle opening and action priority; Bm1 and Bm2 are the preset current values ​​of the first and second boom valve cores corresponding to the pilot handle; xBcOut1 and xBcOut2 are the calculated current values ​​of the first and second bucket tilting valve cores, which need to be smaller than the preset values ​​before use; E1 and E2 are the total current of the valve core opening during the unloading process, which are determined by the pilot pressure and the main pump flow rate; The flow distribution during the reset phase is calculated using the following formula: BmDn1+Am2+xBcIn1=F1 BmDn2+Am1+xBcIn2+Sw=F2 Among them, BmDn1 and BmDn2 are the valve core currents corresponding to the boom descent pilot; F1 and F2 are the total valve core opening currents during the reset process, which are determined by the pilot pressure and the main pump flow rate.

2. The basic flow control method based on a fully electronically controlled positive flow excavator according to claim 1, characterized in that: It also includes the controller automatically adjusting the flow distribution according to the operator's habits and working conditions, so that the excavator can achieve the corresponding performance under different working conditions.

3. The basic flow control method based on a fully electronically controlled positive flow excavator according to claim 1, characterized in that: The hydraulic cylinder adopts a flow-compensated directional valve, which includes a main throttle valve and a flow replenishment valve.

4. The basic flow control method based on a fully electronically controlled positive flow excavator according to claim 1, characterized in that: It also includes using modeling and simulation techniques to model hydraulic systems, identify performance bottlenecks and potential failure points by simulating system behavior under different working conditions, and optimize system design.