A load matching control method and system for a hydraulic pump of a construction machine

Abstract

The application relates to the technical field of hydraulic control of engineering machinery, and discloses an engineering machinery hydraulic pump load matching control method and system. Action instructions, load cavity pressure, pre-valve pressure, pump outlet pressure and spool response state of each action branch are collected, target flow, minimum demand pressure, supply pressure margin and layered response time delay group of each branch are determined, and a dynamic critical branch is determined according to effective residual time and supply pressure margin. Pump control instructions are generated according to the above, so that the variable pump can pre-establish supply pressure and open the main valve of each branch in stages. Pump valve timing parameters are corrected according to the arrival order of the pump outlet pressure front, the pre-valve pressure front of the dynamic critical branch and the spool response front, and the pump valve timing parameters are used for next cycle control. The application can coordinate pump valve response under the conditions of composite action and response time delay change, inhibit transient supply pressure under-matching, and reduce unnecessary continuous pressure margin and throttling loss.

Description

Technical Field

[0001] This invention relates to the field of hydraulic control technology for construction machinery, specifically to a load matching control method and system for hydraulic pumps in construction machinery. Background Technology

[0002] Construction machinery such as mini excavators typically use variable displacement hydraulic pumps to supply oil to multiple parallel actuators. Each actuator controls a hydraulic cylinder or hydraulic motor via a multi-connected main valve. Existing load-sensitive control generally determines the pump outlet pressure by adding a fixed pressure margin to the current highest load pressure, and adjusts the variable displacement pump displacement and main valve opening according to the action command to meet the flow and pressure requirements in complex actions.

[0003] When switching between compound actions, or when oil temperature or power source speed changes, the pump swashplate response, pump outlet pressure establishment, pipeline pressure propagation, and main valve spool movement have different and varying time delays. The branch with the highest load at present is not necessarily the branch that will first experience insufficient pressure. When controlling according to the highest load and fixed pressure margin, the main valve may have already opened before the required pressure has arrived, causing transient underpressure, flow shortage, sudden drop in actuator speed, and pressure shock. If the fixed pressure margin is increased for a long time to avoid this problem, it will increase throttling losses, hydraulic oil heating, and power source load fluctuations. Summary of the Invention

[0004] In view of the above-mentioned problems in the prior art, the present invention provides the following technical solution: This invention provides a load matching control method for hydraulic pumps in engineering machinery, comprising: S1. Collect the action commands, load chamber pressure, valve inlet pressure, pump outlet pressure of variable pump, and valve core response status of each action branch. S2. Determine the target flow rate, minimum required pressure, and supply pressure margin of each action branch according to the action command, the load chamber pressure, and the valve inlet pressure, and determine the hierarchical response delay group according to the pump outlet pressure, the valve inlet pressure, and the valve core response state. S3. Determine the effective remaining time of each action branch based on the pressure supply margin, the minimum required pressure, the rate of change of the valve inlet pressure, and the hierarchical response delay group, and determine the dynamic critical branch according to the ascending order of the effective remaining time, the ascending order of the pressure supply margin, the descending order of the minimum required pressure, and the priority of the pre-stored branch. S4. Determine pump control commands based on the minimum required pressure, the target flow rate, and the dynamic critical branch; enable the variable pump to establish pressure supply according to the pump control commands; and open the main valves of each action branch in stages according to the dynamic critical branch and the pressure supply margin. S5. Based on the arrival order of the pump outlet pressure front, the valve inlet pressure front of the dynamic critical branch, and the valve core response front, the pre-stored pump pre-establishment parameters and the branch valve release parameters are corrected to obtain pump-valve timing parameters, and the pump-valve timing parameters are used to control the variable pump and the main valve in the next cycle.

[0005] Preferably, determining the target flow rate, minimum required pressure, and supply pressure margin of each operating branch based on the action command, the load chamber pressure, and the inlet valve pressure includes: According to the The target flow rate is determined by the action commands of each action branch and the pre-stored valve characteristics. and the target traffic Corresponding target valve port pressure difference ; The first The load chamber pressure of each action branch Pressure difference with the target valve port The sum is determined as the minimum demand pressure. ; The first The pressure before the valve in each actuation branch With the minimum demand pressure The difference is determined as the supply pressure margin. The target flow rate, the minimum required pressure, and the supply pressure margin of each action branch are obtained.

[0006] Preferably, the step of determining the hierarchical response delay group based on the pump outlet pressure, the valve inlet pressure, and the valve core response state includes: Detect the start time of the action command Pump outlet pressure leading moment , No. The moment of the valve inlet pressure front of each action branch and valve core response leading moment This forms a stress response event; Calculate based on the pressure response event , and The pump-side response delay Branch response delay of each action branch Valve-side response delay The hierarchical response delay group is formed by assembling the hierarchical response delay group.

[0007] Preferably, the pressure response event is a valid pressure response event where the action command is monotonous, the relief valve is not open, the variable pump is not subject to power limitation, no action reversal occurs, and the pressure signal does not exceed the range. The hydraulic oil temperature and the speed of the variable pump are obtained, and the oil temperature range and speed range are determined according to the hydraulic oil temperature and the speed of the variable pump, respectively. The pump-side response delay, branch response delay, and valve-side response delay in the hierarchical response delay group are stored separately according to oil temperature range and speed range, and are only updated using the effective pressure response events within the corresponding range in a bounded weighted manner.

[0008] Preferably, when any data of the pump outlet pressure, the valve inlet pressure, or the valve core response state is missing, exceeds the range, or violates the causal sequence of the pressure front, the variable pump is controlled according to the maximum effective load chamber pressure of each actuation branch and the fixed pressure margin, and the opening rate of the main valve of each actuation branch is limited.

[0009] Preferably, the step of determining the effective remaining time of each action branch based on the supply pressure margin, the minimum required pressure, the rate of change of the inlet pressure, and the hierarchical response delay group, and determining the dynamic critical branch in ascending order of the effective remaining time, ascending order of the supply pressure margin, descending order of the minimum required pressure, and priority of the pre-stored branches, includes: The first The pressure margin, minimum required pressure, and inlet pressure of each operating branch are respectively denoted as: , and ,when Determine the margin depletion time ,when and Time to determine In other cases, determine It is infinitely large; The pump-side response delay in the hierarchical response delay group, the first The branch response delay and valve-side response delay of each action branch are denoted as follows: , and Calculate the pressure hysteresis. and ; Will Determined as the number The effective remaining time of each action branch, and in sequence according to The dynamic critical branch is determined by prioritizing the pressure margin from small to large, the minimum demand pressure from large to small, and the pre-stored branch priority, thereby obtaining the effective remaining time and the dynamic critical branch for each action branch.

[0010] Preferably, determining the pump control command based on the minimum required pressure, the target flow rate, and the dynamic critical branch includes: The response time domain is determined according to the hierarchical response delay group. The maximum value of the minimum demand pressure of each action branch is taken as the static supply pressure lower limit. The dynamic supply pressure candidate value is determined according to the predicted minimum demand pressure and pipeline pressure drop of the dynamic critical branch in the response time domain. The maximum value of the static supply pressure lower limit and the dynamic supply pressure candidate value and the minimum value of the safe pressure upper limit are determined as the pump target pressure. The available power of the power source is obtained, and the initial target pump flow rate is determined based on the sum of the target flow rates of each operating branch, the pre-calibrated pipeline compression replenishment amount, and the leakage compensation amount. When the hydraulic power corresponding to the initial target pump flow rate and the target pump pressure does not exceed the available power of the power source, the initial target pump flow rate is determined as the target pump flow rate. When it exceeds the available power of the power source, the upper limit of the allocable pump flow rate is determined based on the available power of the power source and the target pump pressure. The minimum value between the minimum maintenance flow rate of the dynamic critical branch and the upper limit of the allocable pump flow rate is allocated to the dynamic critical branch, and the remaining allocable pump flow rate is allocated according to the target flow rate ratio of the remaining operating branches to obtain the target pump flow rate. Based on the target pump pressure, the target pump flow rate, and the pre-stored variable pump speed-displacement characteristics, a displacement control command is generated, and the displacement control command is used as the pump control command to obtain the pump control command.

[0011] Preferably, the step of opening the main valve of each action branch in stages according to the dynamic critical branch and the pressure supply margin specifically includes: At the start of the action command, the current supply pressure margin support flow rate is determined based on the pre-stored valve port characteristics, and the main valves of each action branch are opened so that the flow rate does not exceed the expected amount of the current supply pressure margin support flow rate. When the pressure margin of the dynamic critical branch enters the pre-calibrated allowable margin range, the main valve of the dynamic critical branch is adjusted to the target opening corresponding to the target flow rate, and the opening rate of the main valves of the other operating branches is limited until the pressure front of the valve of the dynamic critical branch is reached, thus completing the phased opening of the main valves of each operating branch.

[0012] Preferably, the process of correcting the pre-stored pump pre-establishment parameters and branch valve release parameters according to the arrival order of the pump outlet pressure front, the valve inlet pressure front of the dynamic critical branch, and the valve core response front to obtain pump-valve timing parameters, and using the pump-valve timing parameters to control the variable pump and the main valve in the next cycle, includes: Within the response window defined by the hierarchical response delay group, the under-margin area and the over-margin area exceeding the pre-calibrated upper limit of the allowable margin are calculated based on the supply pressure margin. When the valve core response front is earlier than the pump outlet pressure front and the under-margin area exceeds the corresponding allowable range, the pump pre-setup parameter is increased according to the under-margin area; when the pump outlet pressure front is no later than the valve core response front, the valve inlet pressure front of the dynamic critical branch is later than the valve core response front, and the under-margin area exceeds the corresponding allowable range, the branch valve release parameter is increased according to the under-margin area; when the pump outlet pressure front is earlier than the valve core response front, the valve inlet pressure front of the dynamic critical branch is no later than the valve core response front, and the excess area exceeds the corresponding allowable range, the pump pre-setup parameter is decreased according to the excess area; otherwise, the pump pre-setup parameter and the branch valve release parameter remain unchanged. The parameters that have been corrected are limited according to the pre-calibrated stable range, while the parameters that have not been corrected are kept at their original values. The pump pre-establishment parameters and the branch valve release parameters that have been limited or kept at their original values ​​are determined as pump valve timing parameters. The pump valve timing parameters are then used to control the variable pump and the main valve in the next cycle.

[0013] The present invention also provides a load matching control system for hydraulic pumps in engineering machinery, the system being used to implement the above-described method, and the system comprising: The status acquisition module is used to collect the action commands of each action branch, the load chamber pressure, the valve inlet pressure, the pump outlet pressure of the variable pump, and the valve core response status. The margin and time delay determination module is used to determine the target flow rate, minimum demand pressure and supply pressure margin of each action branch based on the action command, the load chamber pressure and the valve inlet pressure, and to determine the hierarchical response time delay group based on the pump outlet pressure, the valve inlet pressure and the valve core response state. The critical branch determination module is used to determine the effective remaining time of each action branch based on the pressure margin, the minimum demand pressure, the rate of change of the valve inlet pressure, and the hierarchical response delay group, and to determine the dynamic critical branch according to the effective remaining time in ascending order, the pressure margin in ascending order, the minimum demand pressure in descending order, and the priority of the pre-stored branches. The pump-valve coordination module is used to determine pump control commands based on the minimum required pressure, the target flow rate, and the dynamic critical branch, to enable the variable pump to establish pressure supply according to the pump control commands, and to open the main valves of each action branch in stages according to the dynamic critical branch and the pressure supply margin. The parameter correction module is used to correct the pre-stored pump pre-establishment parameters and branch valve release parameters according to the arrival order of the pump outlet pressure front, the valve front pressure front of the dynamic critical branch and the valve core response front, to obtain pump valve timing parameters, and use the pump valve timing parameters to control the variable pump and the main valve in the next cycle. Beneficial effects

[0014] The technical solution provided by this invention has the following beneficial effects: 1. By combining the pressure margin depletion time of each action branch with the pump-side response delay, branch response delay and valve-side response delay, the pressure lag and effective remaining time are calculated. Based on the effective remaining time, pressure margin, minimum demand pressure and pre-stored branch priority, a unique dynamic critical branch is determined, so that the controlled object changes from the current highest load branch to the branch that is expected to be the first to experience insufficient pressure. This allows for early identification of transient undermatch risks during the switching process of compound actions, shortening the duration of undervoltage and flow shortage and reducing the sudden drop in actuator speed.

[0015] 2. By identifying pump-side response delay, branch response delay, and valve-side response delay from the effective pressure response events during the normal operation of engineering machinery, and storing and updating them separately according to oil temperature range and variable pump speed range, the time delay effects of pump pressure establishment, pipeline pressure propagation, and valve core action can be characterized in layers. This enables dynamic critical branch judgment and pump valve control to adapt to changes in oil temperature and speed, reducing control deviations caused by mismatch between fixed time delay parameters and actual response states.

[0016] 3. By comprehensively considering the lower limit of static supply pressure, candidate values ​​of dynamic supply pressure, upper limit of safe pressure, and available power of the power source, the target pressure and target flow rate of the pump are determined. The variable pump is pre-established with supply pressure, and the main valves of each operating branch are opened in stages according to the current supply pressure margin. This can coordinate the timing of pump-side supply pressure establishment and valve-side flow, suppress the premature opening of non-critical branches from occupying the pump flow, reduce pressure shock and speed fluctuations in dynamic critical branches, avoid maintaining a high fixed pressure margin for a long time, and reduce throttling losses and unit operating energy consumption.

[0017] 4. By calculating the under-margin area and over-margin area within the response window defined by the hierarchical response delay group, and correcting the pump pre-setup parameters and branch valve release parameters according to the arrival order of the pump outlet pressure front, the dynamic critical branch valve front pressure front, and the valve core response front, the under-match cause can be mapped to the pump-side or branch valve-side control parameters. After stabilization interval limiting, the pump valve timing parameters are used for the next control cycle, which can reduce the under-margin or over-margin cycle by cycle, avoiding supply pressure peaks and control fluctuations caused by excessive parameter correction. Attached Figure Description

[0018] Figure 1 A schematic diagram illustrating the steps of a load matching control method for a hydraulic pump in engineering machinery provided by the present invention; Figure 2 A schematic diagram of the overall process of a load matching control method for hydraulic pumps in engineering machinery provided by the present invention; Figure 3A schematic diagram of the structure of a hydraulic pump load matching control system for engineering machinery provided by the present invention; Figure 4 Comparison diagram of transient load matching effect of composite action switching process provided by the present invention; Figure 5 A comparison chart of the duration of under-margin under different oil temperatures and variable pump speed ranges provided by the present invention; Figure 6 The graph shows the integral of throttling loss per unit operation cycle and the comparison of energy consumption per unit operation provided by this invention. Detailed Implementation

[0019] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0020] Example 1

[0021] This embodiment applies to a small excavator with a single variable displacement hydraulic pump and multiple parallel execution branches. For example... Figure 1 As shown, the load matching control method consists of S1 to S5, and is activated when the excavator issues a boom, stick, bucket, or swing action command. The power source drives a variable displacement pump, whose outlet is connected to a multi-unit electro-proportional main valve via a common oil supply line. Each main valve is connected to the boom hydraulic cylinder, stick hydraulic cylinder, bucket hydraulic cylinder, and swing motor, respectively. The variable displacement pump is equipped with an electro-proportional pump displacement adjustment mechanism, and each main valve is equipped with a proportional solenoid and a valve spool position sensor. The load matching controller is connected to the action command device, pressure sensor, valve spool position sensor, pump displacement or swashplate angle sensor, oil temperature sensor, and power source control unit, and outputs control current to the pump displacement adjustment mechanism and the proportional solenoids of each main valve.

[0022] The pressure sensor is configured with a range of 0–35 MPa and outputs an analog voltage of 0.5–4.5V; the valve core position sensor and pump swashplate angle sensor also output analog voltages of 0.5–4.5V. The controller receives analog signals through an acquisition channel with input protection, anti-aliasing filtering, and analog-to-digital conversion functions, and receives the power source speed and available power via a CAN bus. The sampling frequency for the pressure and position channels is configured to 1 kHz, the analog-to-digital conversion result is stored as a 16-bit unsigned integer, and the control cycle is configured to 5 ms. The controller outputs a pump and valve control current of 0–1.6A through a pulse width modulation drive stage with a frequency of 2 kHz. The drive stage is equipped with overcurrent and open-circuit diagnostics; when a diagnostic is triggered, the corresponding output is prevented from increasing further. The above-mentioned range, sampling rate, control cycle, and drive current are the configuration values ​​for this embodiment and can be recalibrated according to the rated pressure of the hydraulic system, the fastest response frequency, and the rated current of the proportional electromagnet.

[0023] The controller establishes a branch status record for each action branch. The branch status record includes the control cycle number, branch identifier, action direction, normalized action command, actuator two-chamber pressure, load chamber pressure, valve inlet pressure, valve spool position, target flow rate, minimum required pressure, supply pressure margin, pressure change rate, effective remaining time, validity flag, parameter version, and sampling timestamp. The control cycle number, branch identifier, and parameter version use 32-bit unsigned integers; the action direction uses 8-bit enumeration; the action command and each physical quantity use 32-bit floating-point numbers; the validity flag uses a Boolean value; and the sampling timestamp uses a 64-bit unsigned integer counted in microseconds. The branch identifier is unique within the same hydraulic system, and the control cycle number and branch identifier together form a unique key for the record. Pressure is expressed in MPa, flow rate in L / min, time in s, temperature in °C, and speed in r / min. Missing data is not replaced with zero; instead, the corresponding field is set to empty and the validity flag is set to invalid. The controller only combines data with the same control cycle number and parameter version to avoid mixing data across cycles or versions.

[0024] In this invention, an actuation branch refers to an independently controllable oil circuit consisting of a valve link of the main valve, an actuator connected to that valve link, and a corresponding detection channel. The load chamber pressure is the chamber pressure that hinders the current action, selected from the two chamber pressures of the actuator based on the direction of action. The inlet pressure is the branch pressure upstream of the main valve inlet throttling port. The minimum required pressure is the minimum pressure that must be reached upstream of the valve to provide the target flow rate to the load chamber. The supply pressure margin is the remaining amount of the inlet pressure relative to the minimum required pressure; a supply pressure margin less than zero indicates insufficient supply pressure in the corresponding branch.

[0025] The pressure front is the first arrival time determined when the change or rate of change of pressure relative to the pre-action steady-state value continuously reaches the calibrated threshold after the action command is issued. The tiered response delay group includes pump-side response delay, branch response delay for each branch, and valve-side response delay. The dynamic critical branch is the only action branch determined based on the effective remaining time and subsequent sequencing conditions; it is not equivalent to the branch with the highest current load chamber pressure. The pump pre-setup parameter represents the advance pressure supply time of the variable pump relative to the target opening of the main valve. The branch valve release parameter represents the release time used by the main valve to transition from the expected opening to the target opening.

[0026] like Figure 2 As shown, in each control cycle, the controller sequentially performs data acquisition, data validity judgment, demand and delay determination, dynamic critical branch determination, pump and valve coordination, and timing parameter correction. When data is abnormal, it enters the fixed pressure margin degradation path; when all action commands are cancelled, it enters low-pressure standby or minimum displacement state; otherwise, it carries the current valid parameter version into the next control cycle.

[0027] S1. Collect the action commands, load chamber pressure, valve inlet pressure, pump outlet pressure of variable pump, and valve core response status of each action branch. During S1 execution, the status acquisition module latches the output of the action command device and the sensor data within the same 10 ms time window at the beginning of each control cycle. Action commands are normalized to -1 to 1, with the sign representing the direction of action and the absolute value representing the intensity of action. The controller selects the corresponding pressure on the inlet side from the two chamber pressures of the actuator as the load chamber pressure based on the direction of action. The valve spool response status includes at least the valve spool position, the displacement direction relative to the position before action, and the position sampling time. After performing dimensional conversion, time alignment, and valid marking on each signal, the status acquisition module generates the branch status record for the current cycle and sends this record to S2. If a field is temporarily unavailable, the field and its valid flag are transmitted together, allowing subsequent steps to select normal or abnormal processing without mistaking missing values ​​for zero values.

[0028] In some implementations, when any data of the pump outlet pressure, the valve inlet pressure, or the valve core response state is missing, exceeds the range, or violates the causal sequence of the pressure front, the variable pump is controlled based on the maximum effective load chamber pressure of each actuation branch and the fixed pressure margin, and the opening rate of the main valve of each actuation branch is limited.

[0029] Specifically, the analog signal is first filtered by a three-point median filter to remove pulse interference, and then filtered by a first-order low-pass filter with a cutoff frequency of 40 Hz to form the control value. Data is considered invalid if the sample is more than 10 ms away from the current control cycle, the pressure exceeds the configured range, the analog-to-digital conversion saturates, the timestamp goes backward, or the rate of change of continuous samples exceeds the sensor's physical upper limit. The pressure front causal sequence requires that the start time of the action command be no later than the pump outlet pressure front and the branch valve inlet pressure front, and the branch valve inlet pressure front must not be earlier than the pump outlet pressure front after deducting a sampling cycle tolerance; the valve core response front is allowed to be earlier or later than the pump outlet pressure front.

[0030] When any abnormal condition is met, the controller suspends the time delay update and timing parameter correction for the current cycle, clears any incomplete pressure response events, and records the fault code, affected branch, and occurrence time. The controller takes the maximum value from the still valid load chamber pressure, adds a 2.5 MPa fixed pressure margin, and takes the smaller value between this and the 28 MPa safety pressure limit to obtain the target pressure for the degraded pump; the opening of each main valve is only allowed to increase at a rate not exceeding 10% of full stroke per second. If there is no effective load chamber pressure, the variable pump maintains a low-pressure standby pressure of 3 MPa or minimum displacement, and the main valves do not increase their opening. Normal calculation resumes after acquiring valid data again for 100 ms, but data during the fault period is not included in the time delay update; after all action commands are canceled, the active fault is cleared and the system enters standby mode.

[0031] S2. Determine the target flow rate, minimum required pressure, and supply pressure margin of each action branch according to the action command, the load chamber pressure, and the valve inlet pressure, and determine the hierarchical response delay group according to the pump outlet pressure, the valve inlet pressure, and the valve core response state. When executing S2, the margin and delay determination module reads the branch status record and the same version of basic parameters generated by S1. As a basic implementation of the main process, this is applied to the... Each branch line is set with a rated flow rate. and basic valve port pressure difference First, according to From normalized action instructions Get the target traffic, then according to Obtain the minimum demand pressure, and in accordance with The pressure margin is obtained. The rated flow rate and basic valve port pressure difference are obtained from the factory configuration of the corresponding actuator at the rated speed, and are stored in L / min and MPa respectively; when the action command exceeds -1 to 1, it is first limited, and when it is in the dead zone, the target flow rate is set to zero.

[0032] For the hierarchical response delay, the controller resamples the action command, pump outlet pressure, pressure before each branch valve, and valve core position to a 5ms time point within a 0.5s base window after the start of the action command, and forms first-order differential sequences for each. For the differential sequences... and response difference sequence In non-negative lag Calculation The summation range is and All valid common index sets and This is the mean value within the set. For the non-negative hysteresis of 0–100 sampling points, calculate the difference between the action command and the pump outlet pressure, the difference between the action command and the pressure difference before the branch valve, and the difference between the action command and the valve core position. The smallest lag with the highest correlation coefficient and not less than 0.6 is selected; when lags are equal, the smaller lag is selected. The sample sizes of the three lags are denoted as follows: , and Control cycle Pump-side response delay Branch response delay Valve-side response delay When the variance of any sequence is zero, If all correlation coefficients are below 0.6 or there are fewer than 50 valid samples, the current delay remains the previous valid value and records constant signal, causal anomaly, or low correlation state. S2 then outputs the demand records for each branch and the hierarchical response delay records for S3 to read; even without using the following further calculation methods, a definite output can be obtained from the inputs listed in the independent steps.

[0033] In some embodiments, determining the target flow rate, minimum required pressure, and supply pressure margin of each operating branch based on the actuation command, the load chamber pressure, and the inlet valve pressure includes: According to the The target flow rate is determined by the action commands of each action branch and the pre-stored valve characteristics. and the target traffic Corresponding target valve port pressure difference ; The first The load chamber pressure of each action branch Pressure difference with the target valve port The sum is determined as the minimum demand pressure. ; The first The pressure before the valve in each actuation branch With the minimum demand pressure The difference is determined as the supply pressure margin. The target flow rate, the minimum required pressure, and the supply pressure margin of each action branch are obtained.

[0034] Valve port characteristics are indexed using "branch identifier - action direction - action command node". Each node includes target flow rate, target valve port differential pressure, target valve spool position, and calibration version. When the action command is located between adjacent nodes, linear interpolation is performed; if it exceeds the endpoint, the value is limited to the endpoint. For hydraulic cylinder branches, the target flow rate can also be obtained by multiplying the desired velocity by the effective working area, and then limited by the allowable flow range in the valve port characteristic table. Pressure is uniformly converted to MPa before calculation. and The calculation results are displayed in 0.01 MPa increments; unrounded values ​​are used for subsequent rate of change and sorting calculations. When the action command of a branch is within the dead zone, its target flow is set to zero and it exits the dynamic critical branch candidate set for this cycle.

[0035] In some embodiments, determining the hierarchical response delay group based on the pump outlet pressure, the valve inlet pressure, and the valve spool response state includes: Detect the start time of the action command Pump outlet pressure leading moment , No. The moment of the valve inlet pressure front of each action branch and valve core response leading moment This forms a stress response event; Calculate based on the pressure response event , and The pump-side response delay Branch response delay of each action branch Valve-side response delay The hierarchical response delay group is formed by assembling the hierarchical response delay group.

[0036] When an action command crosses the dead zone by 0.05 and then remains monotonically changing in the same direction for the next 20ms, the moment of the first crossover is taken as... At the start of the event, the current oil temperature-speed unit's time delay group is read, and then... Determine the response window length, in seconds; This indicates that the calculated values ​​will be restricted to the closed intervals given by the last two parameters. When the pressure change relative to the average value over the first 50ms before the action reaches 0.2MPa, or when the pressure change rate reaches the calibration threshold for three consecutive samples, the timestamp of the first sample that meets the threshold is taken as the pressure front time. When the valve core position changes along the command direction to 2% of the full stroke and remains constant for three consecutive samples, the timestamp of the first sample that meets the threshold is taken as... If any necessary leading edge is missing when the response window ends, the event is marked as incomplete and the delay is not updated.

[0037] Furthermore, the pressure response event is a valid pressure response event where the action command is monotonous, the relief valve is not open, the variable pump is not subject to power limitation, no action reversal occurs, and the pressure signal does not exceed the range. The hydraulic oil temperature and the speed of the variable pump are obtained, and the oil temperature range and speed range are determined according to the hydraulic oil temperature and the speed of the variable pump, respectively. The pump-side response delay, branch response delay, and valve-side response delay in the hierarchical response delay group are stored separately according to oil temperature range and speed range, and are only updated using the effective pressure response events within the corresponding range in a bounded weighted manner.

[0038] The controller determines that the action command is monotonic if the action command within the event window does not reverse and the first-order differential sign does not change; it determines the status of the overflow valve through the overflow valve position switch; if no position switch is set, the opening criterion is that the pump outlet pressure reaches the overflow calibration pressure and continues for three sampling cycles; it determines whether the variable pump is power limited by comparing the power limit flag of the power source control unit and the pump target power with the available power. If any criterion is not met, the event is only saved as a diagnostic record and does not participate in the time delay update.

[0039] This embodiment sets four oil temperature ranges centered at 20℃, 35℃, 50℃, and 65℃, and four engine speed ranges centered at 1200r / min, 1600r / min, 2000r / min, and 2400r / min. The midpoint of adjacent center values ​​serves as the boundary between ranges; internal ranges are closed on the left and open on the right, with the highest range including its right endpoint. Data outside the ranges only reads the factory parameters of the nearest boundary range and is not used for online updates. Each oil temperature-engine speed unit stores the delay value, valid event count, update time, parameter version, and checksum.

[0040] For a valid event, the controller uses Update the corresponding latency, where The number of valid events for this unit before the update. , and This defines the calibration response boundaries for this pump and valve system model. When an event value exceeds the boundary, the original value is retained and the out-of-bounds code is recorded. During writing, the new value, version number, and checksum are first written to the spare parameter area. After successful verification, the valid version is switched. If the new version fails verification after a power failure, the previous complete version continues to be used.

[0041] S3. Determine the effective remaining time of each action branch based on the pressure supply margin, the minimum required pressure, the rate of change of the valve inlet pressure, and the hierarchical response delay group, and determine the dynamic critical branch according to the ascending order of the effective remaining time, the ascending order of the pressure supply margin, the descending order of the minimum required pressure, and the priority of the pre-stored branch. During S3 execution, the critical branch determination module combines the pressure margin, minimum required pressure, valve inlet pressure change rate, and current oil temperature-speed unit delay of each effective action branch into an urgency input vector. As a basic implementation of the main process, the controller uses a "urgency input vector - effective remaining time" mapping table to obtain the effective remaining time of each branch. This table is generated during the calibration phase of the same model hydraulic system: by changing the pressure margin, minimum required pressure, valve inlet pressure change rate, and the grid containing the pump-side, branch-side, and valve-side delays respectively, and repeatedly executing monotonic ramp loading three times without triggering overflow and power limits, the time from the current sampling time to the first time the pressure margin is not greater than zero is recorded, and the corresponding pressure propagation lag is subtracted; the median of the three results is taken as the effective remaining time of the grid node. Nodes that do not experience margin depletion within the calibration window are saved as infinity. At runtime, multidimensional piecewise linear interpolation is performed on adjacent complete nodes. When the input exceeds the calibration boundary, the amplitude is limited to the nearest boundary. When a node participating in the interpolation is missing, the complete node with the smallest distance is used. When there are no complete nodes in the entire table, a degraded path is entered.

[0042] After obtaining the effective remaining time, the controller sequentially sorts the branches according to the following order: effective remaining time in ascending order, pressure margin in ascending order, minimum demand pressure in descending order, and the priority of each distinct pre-stored branch. The first item in the sort is the dynamic critical branch. If there are no effective candidate branches, an empty flag is output and the system enters a degraded path; if there are candidate branches, the effective remaining time of each branch, the unique dynamic critical branch flag, and the sorting version are output for use by S4.

[0043] In some implementations, determining the effective remaining time of each action branch based on the supply pressure margin, the minimum required pressure, the rate of change of the inlet pressure, and the tiered response delay group, and determining the dynamic critical branch in ascending order of the effective remaining time, ascending order of the supply pressure margin, descending order of the minimum required pressure, and the priority of the pre-stored branches, includes: The first The pressure margin, minimum required pressure, and inlet pressure of each operating branch are respectively denoted as: , and ,when Determine the margin depletion time ,when and Time to determine In other cases, determine It is infinitely large; The pump-side response delay in the hierarchical response delay group, the first The branch response delay and valve-side response delay of each action branch are denoted as follows: , and Calculate the pressure hysteresis. and ; Will Determined as the number The effective remaining time of each action branch, and in sequence according to The dynamic critical branch is determined by prioritizing the pressure margin from small to large, the minimum demand pressure from large to small, and the pre-stored branch priority, thereby obtaining the effective remaining time and the dynamic critical branch for each action branch.

[0044] The controller calculates the pressure change rate using current and historical values ​​spaced five control cycles apart. ,in When the participating value is invalid, the branch does not calculate the finite margin exhaustion time. Infinity is represented using an independent status code and is not included in the subtraction with the maximum floating-point number. The effective remaining time can be negative; a negative value indicates that the supply hysteresis has exceeded the margin exhaustion time. The sort key is... ,in The pre-stored priorities are distinct; if two time values ​​differ by no more than one control cycle, they are treated as equal and the next sorting item is compared. When all margin depletion times are infinite, the supply pressure margin, minimum demand pressure, and priority are compared, thus each set of valid inputs yields a unique result.

[0045] In a set of calculations that run through subsequent steps, the target flow rates for the boom, stick, and bucket branches are 45 L / min, 38 L / min, and 20 L / min, respectively; the target valve differential pressures are 1.8 MPa, 1.6 MPa, and 1.5 MPa, respectively; and the load chamber pressures are 17.0 MPa, 16.0 MPa, and 11.5 MPa, respectively. This yields minimum demand pressures of 18.8 MPa, 17.6 MPa, and 13.0 MPa. The inlet valve pressures are 19.6 MPa, 18.1 MPa, and 14.0 MPa, respectively, with supply margins of 0.8 MPa, 0.5 MPa, and 1.0 MPa, respectively. The minimum demand pressure change rates are 0.8 MPa / s, 5.0 MPa / s, and 0.5 MPa / s, respectively; the inlet valve pressure change rates are 0.6 MPa / s, 2.5 MPa / s, and 0.7 MPa / s, respectively; and the margin depletion times are 4.0 s, 0.2 s, and infinity, respectively.

[0046] The pump-side response delay in the current delay group is 0.08 s, the branch response delays for the three branches are 0.04 s, 0.07 s, and 0.05 s, respectively, and the valve-side response delays are 0.06 s, 0.05 s, and 0.07 s, respectively. The corresponding pressure supply hysteresis is 0.06 s, 0.10 s, and 0.06 s, with effective remaining times of 3.94 s, 0.10 s, and infinity. Therefore, the boom branch is identified as the dynamically critical branch, despite the higher minimum required pressure of the boom branch.

[0047] S4. Determine pump control commands based on the minimum required pressure, the target flow rate, and the dynamic critical branch; enable the variable pump to establish pressure supply according to the pump control commands; and open the main valves of each action branch in stages according to the dynamic critical branch and the pressure supply margin. During execution of S4, the pump-valve coordination module reads the minimum required pressure and target flow rate output from S2, as well as the dynamic critical branch identifier output from S3. As a basic implementation of the main process, the controller adds the maximum value of the minimum required pressure of each branch to a 1.5 MPa base supply pressure margin, and takes the smaller value between this and the upper limit of the variable pump's rated pressure to obtain the base pump target pressure; it then limits the sum of the target flow rates of all effective branches to between 0 and the variable pump's rated flow rate to obtain the pump target flow rate. The controller is based on Determine the target pump displacement, where The unit is L / min. This refers to the pump speed, expressed in r / min. Pump volumetric efficiency, The unit is mL / r; pump speed is ineffective or It will then enter the downgrade path.

[0048] On the main valve side, the controller first causes each actuating branch to enter the first stage opening of 20% of its target valve core position. When the pressure margin of the dynamic critical branch is not less than zero, the branch is adjusted to the target opening, and the remaining branches are limited to 50% of the target opening. After detecting the front pressure rise of the dynamic critical branch valve, the remaining branches are then transitioned to their respective target openings. The percentage opening is calculated from the target valve core position and is limited by the physical stroke of the valve core. The controller first outputs a displacement command to the pump displacement adjustment mechanism, and then corrects the pump valve current in a closed loop based on pump displacement feedback, pump outlet pressure feedback, and valve core position feedback. When feedback times out, the previous safety command is maintained and the main valve opening is not increased, and the system switches to a degraded path. Under normal conditions, the pump control status and valve core target position are output for S5 to evaluate the response of this cycle.

[0049] In some implementations, determining the pump control command based on the minimum required pressure, the target flow rate, and the dynamic critical branch includes: The response time domain is determined according to the hierarchical response delay group. The maximum value of the minimum demand pressure of each action branch is taken as the static supply pressure lower limit. The dynamic supply pressure candidate value is determined according to the predicted minimum demand pressure and pipeline pressure drop of the dynamic critical branch in the response time domain. The maximum value of the static supply pressure lower limit and the dynamic supply pressure candidate value and the minimum value of the safe pressure upper limit are determined as the pump target pressure. Obtain the available power of the power source, and determine the initial target flow rate of the pump based on the sum of the target flow rates of each action branch, the pre-calibrated pipeline compression oil replenishment amount, and the leakage compensation amount. When the hydraulic power corresponding to the initial target pump flow rate and the target pump pressure does not exceed the available power of the power source, the initial target pump flow rate is determined as the target pump flow rate; when it exceeds the available power of the power source, the upper limit of the allocable pump flow rate is determined according to the available power of the power source and the target pump pressure, and the minimum value between the minimum maintenance flow rate of the dynamic critical branch and the upper limit of the allocable pump flow rate is allocated to the dynamic critical branch, and the remaining allocable pump flow rate is allocated according to the target flow rate ratio of the remaining operating branches to obtain the target pump flow rate; Based on the target pump pressure, the target pump flow rate, and the pre-stored variable pump speed-displacement characteristics, a displacement control command is generated, and the displacement control command is used as the pump control command to obtain the pump control command.

[0050] The response time domain takes the dynamic critical branch And it is limited within the range of 50–400 ms. The minimum demand pressure is predicted using... subscript Indicates a dynamic critical branch. This indicates the response time domain. Pipeline pressure drop is obtained by interpolating the predicted target flow rate from the branch flow-pressure drop calibration table. Available power from the power source is the available hydraulic power obtained by subtracting auxiliary load from the allocable shaft power provided by the power source control unit and multiplying it by the pump's overall efficiency; communication interface timeout triggers a degradation path. The minimum sustaining flow rate for dynamic critical branches is calculated according to... Confirmed, among which The ratio of the actuator's minimum allowable speed to the target speed is calibrated, with a configuration range of 0.6 to 0.9. The resulting flow rate is then limited by the minimum stable valve orifice flow rate and the target flow rate of that branch.

[0051] Using the aforementioned data, with a response time of 0.15 s, the predicted minimum demand pressure for the boom branch is... The calibrated pipeline pressure drop is 0.8 MPa, and the dynamic supply pressure candidate value is 19.15 MPa; the static supply pressure lower limit is 18.8 MPa, therefore the pump target pressure is 19.15 MPa. The sum of the target flow rates of the three branches is 103 L / min, the pipeline compression replenishment oil rate and leakage compensation rate are 4 L / min and 2 L / min respectively, the initial pump target flow rate is 109 L / min, and the corresponding hydraulic power is... kW. When the available hydraulic power of the power source is 24 kW, the upper limit of the distributable pump flow rate is kW. L / min.

[0052] When the minimum sustaining flow rate of the boom branch is 30 L / min, first allocate 30 L / min to the boom branch, and then allocate the remaining 45.20 L / min according to the target flow rate of 45 L / min for the boom and bucket. 20 parts were dispensed, yielding 31.29 L / min and 13.91 L / min. At a pump speed of 1600 r / min and a volumetric efficiency of 0.92, the required displacement is: mL / r. The controller interpolates the feedforward displacement from the speed-displacement characteristic table, uses the difference between the pump target pressure and the pump outlet pressure as the feedback error, corrects the feedforward displacement through a proportional-integral adjustment with integral limiting, and then obtains the displacement control command through dual limiting of allowable displacement and pump target flow. The proportional and integral coefficients are calibrated through the step response at rated oil temperature, and the acceptance condition is that the pump outlet pressure does not oscillate continuously and the displacement current is not saturated. If the sum of the target flow of the other branches is zero, proportional allocation is not performed, and the remaining flow is reserved as unallocated flow; if the initial hydraulic power does not exceed the limit, the initial pump target flow is used directly.

[0053] Furthermore, the step of opening the main valve of each action branch in stages according to the dynamic critical branch and the pressure supply margin specifically includes: At the start of the action command, the current supply pressure margin support flow rate is determined based on the pre-stored valve port characteristics, and the main valves of each action branch are opened so that the flow rate does not exceed the expected amount of the current supply pressure margin support flow rate. When the pressure margin of the dynamic critical branch enters the pre-calibrated allowable margin range, the main valve of the dynamic critical branch is adjusted to the target opening corresponding to the target flow rate, and the opening rate of the main valves of the other operating branches is limited until the pressure front of the valve of the dynamic critical branch is reached, thus completing the phased opening of the main valves of each operating branch.

[0054] The controller determines the support flow rate for each branch based on the current pressure margin, oil temperature, and the main valve flow-opening characteristic table, and then interpolates in reverse to obtain the expected opening. When the pressure margin is less than or equal to zero, the expected opening is maintained at the minimum position required to eliminate the mechanical dead zone; when the pressure margin is greater than zero, the calculated flow rate corresponding to the expected opening must not exceed the support flow rate. The allowable margin range for the dynamic critical branch is configured as 0.2–1.0 MPa, and it is considered to have entered the range when it equals the boundary. After entering this range, the dynamic critical branch transitions to the target opening; the opening of other branches is limited by the configured slope before the pressure front of the dynamic critical branch is reached, and the stage restriction is lifted after the pressure front is reached. The target position of the main valve is converted into feedforward current through the valve core position-current calibration table and corrected by the valve core position feedback closed loop. If no pressure front is detected before the end of the response window, the main valve does not continue to increase its opening, the controller records the timeout status and enters the degradation path.

[0055] S5. Based on the arrival order of the pump outlet pressure front, the valve inlet pressure front of the dynamic critical branch, and the valve core response front, the pre-stored pump pre-establishment parameters and the branch valve release parameters are corrected to obtain pump-valve timing parameters, and the pump-valve timing parameters are used to control the variable pump and the main valve in the next cycle.

[0056] When executing S5, the parameter correction module reads the dynamic critical branch identifier and the pump outlet pressure front during this cycle. The pressure front of the valve in this branch line Valve core response leading edge In addition to the current pump pre-set parameters and branch valve release parameters. As a basic implementation of the main process, the single-cycle correction step size will be... Configured to 5 ms: when At that time, the pump pre-set parameters increased. The branch valve release parameter is maintained; when At that time, the release parameter of the branch valve port increases. The pump's pre-set parameters are maintained; when , and At that time, the pump pre-set parameters decrease The branch valve release parameters are maintained. The original value is maintained if all three values ​​are equal or if any of the above valid arrangements are not satisfied. In the event of causal anomalies, missing necessary frontiers, or inconsistent event versions, both parameters retain their original values ​​and the event status is recorded. Pump pre-setup parameters are limited to 0–0.20 s, and branch valve release parameters are limited to 0–0.15 s.

[0057] The new parameters, along with the oil temperature-speed range, event identifier, version number, and checksum, are first written into the spare parameter area. After successful verification, they are activated in the next control cycle. In the next cycle, the pump-valve coordination module outputs a pump control command at the start of the action command, and uses the pump pre-setup parameters as the minimum supply pressure setup time before the main valve leaves the expected opening, and uses the branch valve release parameters as the duration for the main valve to transition from the expected opening to the target opening. This forms a closed loop from leading edge detection and parameter correction to pump-valve control in the next cycle.

[0058] In some embodiments, the pre-stored pump pre-establishment parameters and branch valve release parameters are corrected according to the arrival order of the pump outlet pressure front, the valve inlet pressure front of the dynamic critical branch, and the valve core response front to obtain pump-valve timing parameters, and the pump-valve timing parameters are used to control the variable pump and the main valve in the next cycle, including: Within the response window defined by the hierarchical response delay group, the under-margin area and the over-margin area exceeding the pre-calibrated upper limit of the allowable margin are calculated based on the supply pressure margin. When the valve core response front edge is earlier than the pump outlet pressure front edge and the under-margin area exceeds the corresponding allowable range, the pump pre-establishment parameters are increased according to the under-margin area. When the pump outlet pressure front is no later than the valve core response front, the valve inlet pressure front of the dynamic critical branch is later than the valve core response front, and the under-margin area exceeds the corresponding allowable range, the branch valve release parameter is increased according to the under-margin area. When the pump outlet pressure front is earlier than the valve core response front, the valve inlet pressure front of the dynamic critical branch is no later than the valve core response front, and the excess area exceeds the corresponding allowable range, the pump pre-setup parameter is reduced according to the excess area; otherwise, the pump pre-setup parameter and the branch valve release parameter remain unchanged. The parameters that have undergone correction are limited according to the pre-defined stable range, while the parameters that have not undergone correction are kept at their original values. The pump pre-establishment parameters and the branch valve release parameters, which are either limited or kept at their original values, are determined as pump-valve timing parameters. The pump-valve timing parameters are then used to control the variable pump and the main valve in the next cycle.

[0059] The controller calculates the margin area using discrete integrals. Excess area subscript This represents the dynamic critical branch, with units of MPa·s. To allow for an upper limit of margin, the pre-established parameters for the pump are denoted as follows: The stable range is configured as 0–0.20 s; the branch valve release parameter is recorded as... The stable interval is configured as 0–0.15 s. The allowable values ​​for under-margin area and over-margin area are denoted as follows: and It is calibrated by the pressure and speed tolerance of the same model hydraulic system within the rated operating range, and is bound to the oil temperature-speed range version.

[0060] When the first arrival order is valid, then... Increase pump pre-set parameters; when the second arrival sequence is met, proceed according to... Increase the branch valve release parameter; when the third arrival sequence is met, proceed according to... Reduce the pre-set parameters of the pump. In the formula... , and These represent the moments of the dynamic critical branch valve core response front, the valve inlet pressure front, and the pump outlet pressure front, respectively. and The units are all s / (MPa·s), and are limited by the maximum change in a single period. The first condition is... As the entry point, the second condition is... and As the entry point, the third condition is... and This is the entry point; if the conditions are not met or the area does not exceed the limit, the original value remains.

[0061] For example, the valve core response front is 0.070 s, the pump outlet pressure front is 0.095 s, the under-margin area is 0.12 MPa·s, the allowable value is 0.05 MPa·s, and the original pump pre-set parameters are 0.080 s. Take 0.20 s / (MPa·s). Since the valve core response front precedes the pump outlet pressure front, the correction is... The new pump's pre-set parameters are 0.094 s. In the next cycle, the controller will... Output pump control commands, and s represents the earliest moment when the main valve of the dynamic critical branch deviates from the expected opening; after the supply pressure margin enters the allowable range, the target position of the valve core is... Transition along a linear ramp within a limited time. The transition is completed within a single control cycle. If a write operation is interrupted or verification fails, the old version continues to be used, and no partial update state is created.

[0062] like Figure 2 As shown, if there are still action commands after S5 is completed, the controller returns to S1 and executes the next cycle using the new parameter version; if all action commands are in the dead zone and last for 100ms, the variable pump resumes low-pressure standby or minimum displacement, the main valve returns to the neutral position, and this action event is marked as completed.

[0063] like Figure 3 As shown, this embodiment also provides a load matching control system for hydraulic pumps in engineering machinery. The system is used to implement the above method, and the system includes: The status acquisition module is used to collect the action commands of each action branch, the load chamber pressure, the valve inlet pressure, the pump outlet pressure of the variable pump, and the valve core response status. The margin and time delay determination module is used to determine the target flow rate, minimum demand pressure and supply pressure margin of each action branch based on the action command, the load chamber pressure and the valve inlet pressure, and to determine the hierarchical response time delay group based on the pump outlet pressure, the valve inlet pressure and the valve core response state. The critical branch determination module is used to determine the effective remaining time of each action branch based on the pressure margin, the minimum demand pressure, the rate of change of the valve inlet pressure, and the hierarchical response delay group, and to determine the dynamic critical branch according to the effective remaining time in ascending order, the pressure margin in ascending order, the minimum demand pressure in descending order, and the priority of the pre-stored branches. The pump-valve coordination module is used to determine pump control commands based on the minimum required pressure, the target flow rate, and the dynamic critical branch, to enable the variable pump to establish pressure supply according to the pump control commands, and to open the main valves of each action branch in stages according to the dynamic critical branch and the pressure supply margin. The parameter correction module is used to correct the pre-stored pump pre-establishment parameters and branch valve release parameters according to the arrival order of the pump outlet pressure front, the valve front pressure front of the dynamic critical branch and the valve core response front, to obtain pump valve timing parameters, and use the pump valve timing parameters to control the variable pump and the main valve in the next cycle.

[0064] The load matching controller includes a processor, volatile runtime memory, non-volatile parameter memory, analog input interface, CAN communication interface, and pump / valve drive interface. The control program is executed periodically by the processor. Branch status records and intermediate calculation results are stored in the runtime memory, while valve characteristics, urgency mapping tables, delay groups, and pump / valve timing parameters are stored in the non-volatile parameter memory. The status acquisition module receives signals from the acquisition end via the analog input interface and CAN interface, and outputs branch status records or invalid records with fault codes. The margin and delay determination module reads the status records of the same period and outputs demand records and hierarchical response delay records. The critical branch determination module outputs the effective remaining time, dynamic critical branch identifier, and sorted version. The pump / valve coordination module outputs the pump target pressure, pump target flow rate, displacement control commands, and target current of each main valve, and receives pump displacement and valve core position feedback. The parameter correction module outputs pump / valve timing parameters with version numbers and check codes.

[0065] Each module transmits data through a fixed-length message buffer in the runtime memory. Each message carries a control cycle number, parameter version, validity flag, and checksum. The status acquisition module, margin and delay determination module, critical branch determination module, and pump-valve coordination module transmit data sequentially according to the control link. The pump-valve coordination module provides the parameter correction module with a dynamic critical branch identifier and response window, and the parameter correction module feeds back the new version of the timing parameters to the pump-valve coordination module. If the receiving module detects an inconsistency in the cycle number or version, it refuses to use the same parameters and returns a data asynchronization fault. The pump-valve coordination module has unique write permissions for the pump displacement adjustment mechanism and the main valve proportional solenoid; other modules cannot directly drive the actuator. After the watchdog is reset, the controller verifies the dual copies of the non-volatile parameters and restores the most recent complete version; if both copies fail, the factory default parameters are used and degraded control is entered.

[0066] To explain Figures 4 to 6 The evaluation criteria are as follows: the following data are all used as recalculated deterministic plotting configurations, not as field test records, nor as conclusions drawn from actual measured performance. The three control methods use the same time points, compound action commands, load conditions, oil temperature, variable pump speed, available power source, and evaluation formulas; only the data sequences corresponding to the control methods are replaced.

[0067] like Figure 4 As shown in (a), the horizontal axis represents the time from 0 to 1.2 s, with an interval of 0.1 s. The action switching time is 0.2 s, and the shadow evaluation window is from 0.2 to 0.7 s. The pressure margin sequence for the maximum load fixed margin control is 1.2, 1.2, 1.2, -0.5, -2.3, -1.8, -0.8, 0, 0.5, 0.8, 0.9, 1.0, and 1.0 MPa; the sequence for the load pressure change rate dynamic margin control is 1.2, 1.2, 1.2, 0, -1.35, -0.75, 0.15, 0.75, 0.95, 1.0, 1.0, 1.0, and 1.0 MPa; the sequence for the control method of this invention is 1.2, 1.2, 1.2, 0.45, -0.45, 0.35, 0.9, 1.05, 1.0, 1.0, 1.0, 1.0, and 1.0 MPa. Adjacent nodes are linearly connected. Under this plotting configuration, the absolute value of the minimum negative margin of the corresponding sequence of the control method of the present invention is small and returns to a positive value earlier, which is used to illustrate the direction of action of pump pressure pre-establishment and main valve phased opening on the undermatch process.

[0068] like Figure 4 As shown in (b), the vertical axis represents the actuator speed error, according to... Calculation, where The target speed is given. The speed error sequences for the three control methods are as follows: 0, 0, 0, -10, -28, -24, -15, -7, -2, 0, 0, 0, 0; 0, 0, 0, -6, -18, -13, -6, -2, 0, 0, 0, 0, 0; and 0, 0, 0, -3, -8, -4, -1, 0, 0, 0, 0, 0, 0, in percentage. At the same time point, the sequence with a smaller negative supply pressure margin corresponds to a smaller negative speed error, indicating the technical correlation between improved supply pressure matching and reduced speed drop.

[0069] like Figure 4 As shown in (c), the vertical axis represents the pump outlet pressure. The pressure sequences for the three control methods are as follows: 12, 12, 12, 14, 17, 19.5, 21.5, 22.8, 22.2, 21.8, 21.6, 21.5, and 21.5 MPa; 12, 12, 12, 15, 19, 22, 23.8, 23.2, 22.3, 21.8, 21.6, 21.5, and 21.5 MPa; and 12, 12, 12, 18, 23, 24.6, 23.5, 22.4, 21.8, 21.6, 21.5, 21.5, and 21.5 MPa. The control method of this invention establishes pressure relatively quickly in the early part of the evaluation window, but the peak value is higher than the two control sequences and still lower than the safe pressure limit of 28 MPa, indicating that the improvement in transient matching may be accompanied by a limited peak pressure trade-off.

[0070] Figure 5 A two-dimensional grid is constructed using the center values ​​of the oil temperature range and the variable pump speed range, and the duration of the under-margin is calculated according to... Calculate and convert to milliseconds (ms). The following matrices are arranged from row 1 to row 4 according to oil temperatures of 20℃, 35℃, 50℃, and 65℃, with each row arranged according to engine speeds of 1200 r / min, 1600 r / min, 2000 r / min, and 2400 r / min. Each grid value is only used within the boundaries where sensor data is valid, the overflow valve is not open, and the variable pump is not power-limited; if any of these conditions are not met, the corresponding grid will not participate in time delay updates or effect comparisons.

[0071] like Figure 5 As shown in (a), the configuration matrix for the maximum load fixed margin control is [350,300,260,230], [300,250,215,190], [255,210,180,160], and [230,190,165,150] ms. In this subplot, 350 ms is used at 20 ℃ and 1200 r / min, and 150 ms is used at 65 ℃ and 2400 r / min, to represent the response dependence of the fixed margin baseline to changes in oil temperature and engine speed.

[0072] like Figure 5 As shown in (b), the configuration matrices for dynamic margin control of load pressure change rate are [285,240,210,190], [235,195,165,145], [190,155,130,112], and [165,132,95,55] ms. The values ​​in this subplot are lower than […] in most corresponding grids. Figure 5 (a) is used to indicate the direction of change of the duration of the under-margin when adjusting the margin according to the rate of change of the load pressure.

[0073] like Figure 5 As shown in (c), the configuration matrix of the control method of the present invention is [180,150,130,118], [135,112,96,86], [102,84,70,62], and [90,72,62,58] ms. The values ​​in this subplot in the low temperature and low speed regions are smaller than the two control matrices, used to represent the effect of the partitioned time delay parameter and dynamic critical branch control under conditions where time delay is significant; at 65 ℃ and 2400 r / min, it is 58 ms, slightly higher than... Figure 5 (b) 55 ms is used to preserve the performance trade-offs under boundary conditions. The three subplots together show that the overall response delay is reduced when the oil temperature or engine speed increases.

[0074] Figure 6 The three control methods use the same operating cycle, load spectrum, ambient temperature, power source speed range, and completed workload, and use valid sensor data, unopened overflow valve, and unlimited power variable pump as common effective boundaries. The throttling loss integral is calculated according to... Calculations are made in kJ cycles; unit operating energy consumption is calculated according to... Calculation, where The power supplied by the power source to the hydraulic system. This represents a complete work cycle that reaches the same endpoint. "Repetition 5" in the diagram indicates that integration was performed on each of the five pre-defined calculation sequences, not five field tests. The mean is calculated as follows: The error bar is calculated using the sample standard deviation. .

[0075] like Figure 6As shown in (a), the five sets of throttling loss integrals for the maximum load fixed margin control, load pressure change rate dynamic margin control, and the control method of the present invention are 41.0, 41.0, 42.8, 44.6, 44.6 kJ cycles, 34.4, 34.4, 35.9, 37.4, 37.4 kJ cycles, and 29.4, 29.4, 30.6, 31.8, 31.8 kJ cycles, respectively, resulting in 42.8±1.8, 35.9±1.5, and 30.6±1.2 kJ cycles. Under this deterministic configuration, the throttling loss integral corresponding to the control method of the present invention is relatively low, which is used to represent the direction of the effect of establishing supply pressure according to transient demand and limiting the opening rate of the non-critical branch main valve on the continuous throttling loss.

[0076] like Figure 6 As shown in (b), the unit operating energy consumption for the three control methods is 125.3, 125.3, 128.4, 131.5, 131.5 kJ per cycle; 113.2, 113.2, 115.8, 118.4, 118.4 kJ per cycle; and 114.9, 114.9, 117.4, 119.9, 119.9 kJ per cycle, resulting in energy consumption of 128.4 ± 3.1, 115.8 ± 2.6, and 117.4 ± 2.5 kJ per cycle. The corresponding values ​​of the control method of this invention are lower than the fixed margin configuration but slightly higher than the dynamic margin configuration, representing the conditional trade-off between reducing continuous throttling losses and establishing pump pressure earlier.

[0077] Example 2

[0078] In another embodiment, the variable displacement pump is a motor-driven, electrically controlled displacement pump. The motor controller calculates the available power based on the bus voltage, current limit, inverter temperature, and motor speed, and sends this information to the load matching controller via CAN messages. The load matching controller still determines the target flow rate, minimum required pressure, supply pressure margin, hierarchical response delay group, and dynamic critical branch according to steps S1 to S5, and converts the pump target pressure and pump target flow rate into motor torque commands and pump displacement commands. When communication data times out or the motor controller reports limited power, the corresponding event does not participate in the delay update and enters the degradation path of fixed pressure margin and main valve opening rate limit.

[0079] For a dual-pump system, the operating branches are divided into two non-overlapping sets based on the actual oil supply connection relationship. Each pump determines its dynamic critical branch within its set. When the shared power source is insufficient, the effective remaining time of the corresponding dynamic critical branches of the two pumps is compared first. The pump with the smaller effective remaining time is allocated the smaller of its minimum sustaining flow rate and the current remaining allocable flow rate. If there is still remaining flow rate, the same allocation is made to the other dynamic critical branch. Finally, the remaining flow rate is allocated according to the target flow rate ratio of the remaining branches. When the effective remaining time is equal, the pressure margin, minimum demand pressure, and cross-pump pre-stored priority are compared sequentially. Each pump stores its pump-side response delay and pump pre-setup parameters, and each branch stores its branch response delay, valve-side response delay, and branch valve release parameters.

[0080] The inlet pressure of the branch valve is preferably obtained directly from the inlet pressure sensor. In case of sensor failure, the controller can estimate the inlet pressure by subtracting the calibrated pipeline resistance pressure drop from the pump outlet pressure. The pipeline resistance pressure drop is obtained by interpolation based on the branch flow rate, oil temperature, and pipeline characteristic table. The estimated value is only used for fixed pressure margin degradation control and main valve opening rate limitation; it is not written into the effective pressure response event or updated in the hierarchical response delay group. The actuator can also be a hydraulic motor, with its load chamber pressure selected based on the current direction of rotation, and the target flow rate determined based on the target speed and motor displacement. Except for the flow conversion relationship, the determination of the dynamic critical branch, the phased control of the pump and valve, and the parameter correction link remain unchanged.

[0081] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A load matching control method for a hydraulic pump in engineering machinery, characterized in that, include: S1. Collect the action commands, load chamber pressure, valve inlet pressure, pump outlet pressure of variable pump, and valve core response status of each action branch. S2. Determine the target flow rate, minimum required pressure, and supply pressure margin of each action branch according to the action command, the load chamber pressure, and the valve inlet pressure, and determine the hierarchical response delay group according to the pump outlet pressure, the valve inlet pressure, and the valve core response state. S3. Determine the effective remaining time of each action branch based on the pressure supply margin, the minimum required pressure, the rate of change of the valve inlet pressure, and the hierarchical response delay group, and determine the dynamic critical branch according to the ascending order of the effective remaining time, the ascending order of the pressure supply margin, the descending order of the minimum required pressure, and the priority of the pre-stored branch. S4. Determine pump control commands based on the minimum required pressure, the target flow rate, and the dynamic critical branch; enable the variable pump to establish pressure supply according to the pump control commands; and open the main valves of each action branch in stages according to the dynamic critical branch and the pressure supply margin. S5. Based on the arrival order of the pump outlet pressure front, the valve inlet pressure front of the dynamic critical branch, and the valve core response front, the pre-stored pump pre-establishment parameters and the branch valve release parameters are corrected to obtain pump-valve timing parameters, and the pump-valve timing parameters are used to control the variable pump and the main valve in the next cycle.

2. The method according to claim 1, characterized in that, The process of determining the target flow rate, minimum required pressure, and supply pressure margin of each operating branch based on the action command, the load chamber pressure, and the valve inlet pressure includes: According to the The target flow rate is determined by the action commands of each action branch and the pre-stored valve characteristics. and the target traffic Corresponding target valve port pressure difference ; The first The load chamber pressure of each action branch Pressure difference with the target valve port The sum is determined as the minimum demand pressure. ; The first The pressure before the valve in each actuation branch With the minimum demand pressure The difference is determined as the supply pressure margin. The target flow rate, the minimum required pressure, and the supply pressure margin of each action branch are obtained.

3. The method according to claim 1, characterized in that, The method for determining the hierarchical response delay group based on the pump outlet pressure, the valve inlet pressure, and the valve core response state includes: Detect the start time of the action command Pump outlet pressure leading moment , No. The moment of the valve inlet pressure front of each action branch and valve core response leading moment This forms a stress response event; Calculate based on the pressure response event , and The pump-side response delay Branch response delay of each action branch Valve-side response delay The hierarchical response delay group is formed by assembling the hierarchical response delay group.

4. The method according to claim 3, characterized in that, The pressure response event is a valid pressure response event where the action command is monotonous, the relief valve is not open, the variable pump is not subject to power limitation, no action reversal occurs, and the pressure signal does not exceed the range. The hydraulic oil temperature and the speed of the variable pump are obtained, and the oil temperature range and speed range are determined according to the hydraulic oil temperature and the speed of the variable pump, respectively. The pump-side response delay, branch response delay, and valve-side response delay in the hierarchical response delay group are stored separately according to oil temperature range and speed range, and are only updated using the effective pressure response events within the corresponding range in a bounded weighted manner.

5. The method according to claim 1, characterized in that, When any data of the pump outlet pressure, the valve inlet pressure, or the valve core response state is missing, exceeds the range, or violates the causal sequence of the pressure front, the variable pump is controlled according to the maximum effective load chamber pressure of each actuation branch and the fixed pressure margin, and the opening rate of the main valve of each actuation branch is limited.

6. The method according to claim 1, characterized in that, The process of determining the effective remaining time of each action branch based on the supply pressure margin, the minimum required pressure, the rate of change of the inlet pressure, and the hierarchical response delay group, and determining the dynamic critical branch according to the ascending order of the effective remaining time, the ascending order of the supply pressure margin, the descending order of the minimum required pressure, and the priority of the pre-stored branches, includes: The first The pressure margin, minimum required pressure, and inlet pressure of each operating branch are respectively denoted as: , and ,when Determine the margin depletion time ,when and Time to determine In other cases, determine It is infinitely large; The pump-side response delay in the hierarchical response delay group, the first The branch response delay and valve-side response delay of each action branch are denoted as follows: , and Calculate the pressure hysteresis. and ; Will Determined as the number The effective remaining time of each action branch, and in sequence according to The dynamic critical branch is determined by prioritizing the pressure margin from small to large, the minimum demand pressure from large to small, and the pre-stored branch priority, thereby obtaining the effective remaining time and the dynamic critical branch for each action branch.

7. The method according to claim 1, characterized in that, The step of determining pump control commands based on the minimum required pressure, the target flow rate, and the dynamic critical branch includes: The response time domain is determined according to the hierarchical response delay group. The maximum value of the minimum demand pressure of each action branch is taken as the static supply pressure lower limit. The dynamic supply pressure candidate value is determined according to the predicted minimum demand pressure and pipeline pressure drop of the dynamic critical branch in the response time domain. The maximum value of the static supply pressure lower limit and the dynamic supply pressure candidate value and the minimum value of the safe pressure upper limit are determined as the pump target pressure. The available power of the power source is obtained, and the initial target pump flow rate is determined based on the sum of the target flow rates of each operating branch, the pre-calibrated pipeline compression replenishment amount, and the leakage compensation amount. When the hydraulic power corresponding to the initial target pump flow rate and the target pump pressure does not exceed the available power of the power source, the initial target pump flow rate is determined as the target pump flow rate. When it exceeds the available power of the power source, the upper limit of the allocable pump flow rate is determined based on the available power of the power source and the target pump pressure. The minimum value between the minimum maintenance flow rate of the dynamic critical branch and the upper limit of the allocable pump flow rate is allocated to the dynamic critical branch, and the remaining allocable pump flow rate is allocated according to the target flow rate ratio of the remaining operating branches to obtain the target pump flow rate. Based on the target pump pressure, the target pump flow rate, and the pre-stored variable pump speed-displacement characteristics, a displacement control command is generated, and the displacement control command is used as the pump control command to obtain the pump control command.

8. The method according to claim 1, characterized in that, The main valve that opens each action branch in stages according to the dynamic critical branch and the pressure supply margin specifically includes: At the start of the action command, the current supply pressure margin support flow rate is determined based on the pre-stored valve port characteristics, and the main valves of each action branch are opened so that the flow rate does not exceed the expected amount of the current supply pressure margin support flow rate. When the pressure margin of the dynamic critical branch enters the pre-calibrated allowable margin range, the main valve of the dynamic critical branch is adjusted to the target opening corresponding to the target flow rate, and the opening rate of the main valves of the other operating branches is limited until the pressure front of the valve of the dynamic critical branch is reached, thus completing the phased opening of the main valves of each operating branch.

9. The method according to claim 1, characterized in that, The pre-stored pump pre-establishment parameters and branch valve release parameters are corrected according to the arrival order of the pump outlet pressure front, the valve inlet pressure front of the dynamic critical branch, and the valve core response front to obtain pump-valve timing parameters. These pump-valve timing parameters are then used to control the variable pump and the main valve in the next cycle, including: Within the response window defined by the hierarchical response delay group, the under-margin area and the over-margin area exceeding the pre-calibrated upper limit of the allowable margin are calculated based on the supply pressure margin. When the valve core response front is earlier than the pump outlet pressure front and the under-margin area exceeds the corresponding allowable range, the pump pre-setup parameter is increased according to the under-margin area; when the pump outlet pressure front is no later than the valve core response front, the valve inlet pressure front of the dynamic critical branch is later than the valve core response front, and the under-margin area exceeds the corresponding allowable range, the branch valve release parameter is increased according to the under-margin area; when the pump outlet pressure front is earlier than the valve core response front, the valve inlet pressure front of the dynamic critical branch is no later than the valve core response front, and the excess area exceeds the corresponding allowable range, the pump pre-setup parameter is decreased according to the excess area; otherwise, the pump pre-setup parameter and the branch valve release parameter remain unchanged. The parameters that have been corrected are limited according to the pre-calibrated stable range, while the parameters that have not been corrected are kept at their original values. The pump pre-establishment parameters and the branch valve release parameters that have been limited or kept at their original values ​​are determined as pump valve timing parameters. The pump valve timing parameters are then used to control the variable pump and the main valve in the next cycle.

10. A load matching control system for a hydraulic pump in engineering machinery, characterized in that, The system is used to implement the method of any one of claims 1 to 9, and the system comprises: The status acquisition module is used to collect the action commands of each action branch, the load chamber pressure, the valve inlet pressure, the pump outlet pressure of the variable pump, and the valve core response status. The margin and time delay determination module is used to determine the target flow rate, minimum demand pressure and supply pressure margin of each action branch based on the action command, the load chamber pressure and the valve inlet pressure, and to determine the hierarchical response time delay group based on the pump outlet pressure, the valve inlet pressure and the valve core response state. The critical branch determination module is used to determine the effective remaining time of each action branch based on the pressure margin, the minimum demand pressure, the rate of change of the valve inlet pressure, and the hierarchical response delay group, and to determine the dynamic critical branch according to the effective remaining time in ascending order, the pressure margin in ascending order, the minimum demand pressure in descending order, and the priority of the pre-stored branches. The pump-valve coordination module is used to determine pump control commands based on the minimum required pressure, the target flow rate, and the dynamic critical branch, to enable the variable pump to establish pressure supply according to the pump control commands, and to open the main valves of each action branch in stages according to the dynamic critical branch and the pressure supply margin. The parameter correction module is used to correct the pre-stored pump pre-establishment parameters and branch valve release parameters according to the arrival order of the pump outlet pressure front, the valve front pressure front of the dynamic critical branch and the valve core response front, to obtain pump valve timing parameters, and use the pump valve timing parameters to control the variable pump and the main valve in the next cycle.

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