Construction machinery, control method therefor, electronic device, and storage medium

Abstract

The application discloses an engineering machine, a control method thereof, an electronic device and a storage medium. The method comprises the following steps: determining a current working condition stage of the engineering machine; determining a target rotating speed interval of an engine according to the working condition stage; obtaining a required power of the engine at a next moment when an actual rotating speed of the engine is in the target rotating speed interval; and determining a target torque for controlling the engine under the constraints of the target rotating speed interval and the required power, which meets a preset energy-saving condition. According to the technical scheme, the target rotating speed interval corresponding to different working condition stages is set, the torque meeting the energy-saving condition and the required power at the next moment is determined based on the target rotating speed interval, the working point at different working condition stages can be adjusted based on the corresponding rotating speed interval, and the working point at the same working condition stage can also be adjusted according to the required power, so that the working point of the engine can be dynamically adjusted at different working condition stages and at the same working condition stage, the dynamic optimization of energy consumption is realized, and the energy-saving effect is good.

Description

Technical Field

[0001] This application relates to the field of automatic control technology, and in particular to an engineering machine and its control method, electronic equipment and storage medium. Background Technology

[0002] Construction machinery is versatile, adaptable, and highly reliable, and is widely used in the construction of projects such as urbanization, mineral resource development, transportation infrastructure, and national defense and military engineering.

[0003] To meet the requirements of operational economy and handling performance, construction machinery typically has multiple operating modes and gears. As can be seen from the universal characteristic curve of an engine, for the same engine output power, the fuel consumption rate at its operating point varies depending on the combination of speed and torque. The innermost fuel consumption curve encompasses the economical fuel zone; provided the power requirements are met, the closer the engine's operating point (speed, torque) is to this zone, the lower the fuel consumption.

[0004] However, construction machinery operates on a complex and diverse range of tasks. Taking hydraulic excavators as an example, under the same working conditions (shoveling, slope repair, leveling, breaking, etc.), different stages of the working process (e.g., shoveling can be divided into excavation, lifting and slewing, unloading, and empty bucket return stages) exhibit significant differences in load and flow requirements. These large variations in power demand at the load end will cause drastic fluctuations in engine output power, resulting in the operating point not being stable within the fuel-efficient range, leading to high overall fuel consumption and poor energy-saving performance. Therefore, it is necessary to propose a more effective energy-saving solution for construction machinery. Summary of the Invention

[0005] In view of this, the purpose of this application is to provide an engineering machinery and its control method, electronic equipment and storage medium, which can achieve dynamic optimization of energy consumption and good energy saving effect.

[0006] To achieve the above objectives, this application provides a control method for engineering machinery, the method comprising:

[0007] Determine the current operating stage of the construction machinery;

[0008] The target speed range of the engine is determined based on the aforementioned operating conditions.

[0009] When the actual speed of the engine is within the target speed range, obtain the required power of the engine at the next moment;

[0010] Under the constraints of the target speed range and the required power, a target torque for controlling the engine is determined that satisfies the preset energy-saving conditions.

[0011] In one embodiment, determining the current operating stage of the construction machinery includes:

[0012] Acquire pilot control signal data from the actuators of construction machinery;

[0013] Based on the pilot control signal data, the current operating stage of the construction machinery is identified using a pre-trained operating stage identification model, and the current operating stage of the construction machinery is determined.

[0014] In one embodiment, before determining the target speed range of the engine based on the operating condition stage, the method further includes:

[0015] Obtain operational test data at different working conditions and stages;

[0016] Based on the operational test data, obtain the engine speed distribution frequency corresponding to different operating conditions.

[0017] Gaussian distribution fitting was performed on the engine speed distribution frequency corresponding to the different operating conditions to obtain the fitting results;

[0018] Based on the rotational speed data within a preset range on both sides of the Gaussian distribution mean in the fitting results, the target rotational speed range corresponding to each operating condition stage is set.

[0019] In one embodiment, after determining the target speed range of the engine based on the operating condition stage, the method further includes:

[0020] When the actual speed of the engine is higher than the upper limit of the target speed range, the displacement of the hydraulic pump is increased to increase the speed and reduce the acceleration, thereby reducing the actual speed of the engine.

[0021] When the actual speed of the engine is lower than the lower limit of the target speed range, the displacement of the hydraulic pump is reduced to increase the speed and increase the acceleration, thereby increasing the actual speed of the engine.

[0022] In one embodiment, the preset energy-saving condition includes minimizing the engine's instantaneous fuel consumption rate, and determining the target torque for controlling the engine that satisfies the preset energy-saving condition under the constraints of the target speed range and the required power includes:

[0023] Obtain the target torque range corresponding to the target speed range;

[0024] Under the constraints of the target speed range, the target torque range, and the required power, a target torque for controlling the engine that meets preset energy-saving conditions is determined.

[0025] In one embodiment, obtaining the engine's required power at the next moment when the engine's actual speed is within the target speed range includes:

[0026] When the actual speed of the engine is within the target speed range, acquire the working data corresponding to the current moment and a preset number of moments before the current moment;

[0027] Based on the working data, and using a pre-trained engine demand power prediction model, the engine's demand power at the next moment is predicted.

[0028] In one embodiment, the method further includes: training the engine demand power prediction model;

[0029] The training of the engine demand power prediction model includes:

[0030] Acquire test data and engine output power at different operating conditions and corresponding times;

[0031] The test data of a preset number of moments captured by the time window, and the engine output power of the moment after the latest moment of the time window are used as a set of data to construct the sample data for training the model.

[0032] The test data from each set of data is used as the input to the model to be trained, and the engine output power from each set of data is used as the output of the model to be trained. The model parameters are adjusted to train the engine demand power prediction model.

[0033] In one embodiment, after determining the target torque for controlling the engine that satisfies preset energy-saving conditions under the constraints of the target speed range and the required power, the method further includes:

[0034] The change in outlet pressure of the secondary pressure reducing valve of the hydraulic pump is determined based on the deviation between the target torque and the actual torque of the engine.

[0035] The control current of the secondary pressure reducing valve of the hydraulic pump is determined based on the change in outlet pressure, so as to control the displacement of the hydraulic pump of the engine.

[0036] This application also provides a piece of construction machinery, the construction machinery including an engine and a control device, the control device being configured to:

[0037] Determine the current operating stage of the construction machinery;

[0038] The target speed range of the engine is determined based on the aforementioned operating conditions.

[0039] When the actual speed of the engine is within the target speed range, obtain the required power of the engine at the next moment;

[0040] Under the constraints of the target speed range and the required power, a target torque for controlling the engine is determined that satisfies the preset energy-saving conditions.

[0041] This application also provides an electronic device, including a processor, a memory, and a computer program stored in the memory and executable on the processor, wherein the computer program, when executed by the processor, implements the steps of any of the methods described above.

[0042] This application also provides a computer-readable storage medium storing a computer program that, when executed by a processor, implements the steps of any of the methods described above.

[0043] Based on the above, the engineering machinery and its control method, electronic equipment, and storage medium of this application determine the current operating stage of the engineering machinery, determine the target speed range of the engine based on the operating stage, and obtain the engine's required power at the next moment when the actual engine speed is within the target speed range. Under the constraints of the target speed range and the required power, the target torque for controlling the engine that meets the preset energy-saving conditions is determined. The technical solution of this application sets target speed ranges corresponding to different operating stages, and determines the torque that meets the energy-saving conditions and the required power at the next moment based on the target speed range. This allows the operating point of different operating stages to be adjusted based on the corresponding speed range, and the operating point of the same operating stage can also be adjusted according to the required power. Thus, the engine operating point can be dynamically adjusted in different operating stages and in the same operating stage, achieving dynamic optimization of energy consumption and good energy-saving effect. Attached Figure Description

[0044] To more clearly illustrate the technical solutions of the embodiments of this application, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of this application and should not be regarded as a limitation of the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0045] Figure 1 This is a flowchart illustrating a control method for engineering machinery provided in an embodiment of this application.

[0046] Figure 2 A schematic flowchart illustrating the control method for engineering machinery provided in an embodiment of this application.

[0047] Figure 3 This is a schematic diagram of the structure of an engineering machine provided in an embodiment of this application. Detailed Implementation

[0048] The specific embodiments of this application will now be described in detail with reference to the accompanying drawings. Obviously, the described embodiments are merely a part of the embodiments of this application, and not all of them. Based on the description of this application, all other embodiments obtained by those skilled in the art without inventive effort are within the scope of protection of this application.

[0049] In the description of this application, unless otherwise expressly specified and limited, the terms "set," "install," "connect," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium. Those skilled in the art can understand the specific meaning of the above terms based on the specific circumstances.

[0050] The terms “first,” “second,” “third,” etc., are used merely to distinguish numerical values ​​or elements with similar properties, rather than to indicate or imply relative importance or a specific order.

[0051] The terms “include,” “comprising,” or any other variation thereof are intended to cover non-exclusive inclusion, which includes not only the elements listed but also other elements not expressly listed.

[0052] Figure 1 This is a flowchart illustrating a control method for engineering machinery provided in one embodiment of this application. Figure 1 As shown, the control method for engineering machinery of this application includes:

[0053] Step S1: Determine the current operating stage of the construction machinery.

[0054] The term "operating condition stage" refers to the current stage of the construction machinery within its operating condition. Construction machinery can include hydraulic excavators, cranes, aerial work platforms, and concrete pump trucks. Taking a hydraulic excavator as an example, the current operating condition might be dumping, slope repair, leveling, or breaking. For dumping, different operating condition stages could be divided into excavation, lifting and slewing, unloading, and empty bucket return. Similarly, for a crane, when the current operating condition is hoisting, the operating condition stages could be divided into hoisting preparation, hoisting, unloading, empty return, and idle stages.

[0055] Step S2: Determine the target speed range of the engine based on the operating condition stage.

[0056] Different operating conditions have corresponding speed ranges, and the speed ranges for different operating conditions can be the same or different.

[0057] Step S3: When the actual engine speed is within the target speed range, obtain the engine's required power at the next moment.

[0058] Step S4: Under the constraints of the target speed range and required power, determine the target torque for controlling the engine that meets the preset energy-saving conditions.

[0059] By setting a target speed range, preset energy-saving conditions, and constraints on the power demand at the next moment, the engine's target torque meets the energy-saving conditions while satisfying the power demand at the next moment. Thus, the engine's target torque is the optimal energy-saving option within the target speed range of the current operating condition. The operating point (speed and torque) of the same operating condition can vary with the power demand. For different operating conditions, the engine operating point can be adjusted based on different speed ranges. Therefore, the engine operating point can be dynamically adjusted in different operating conditions and in the same operating condition, achieving dynamic optimization of energy consumption and good energy-saving effect.

[0060] Furthermore, the engine's target torque is the torque required to meet the power demand at the next moment, thus enabling proactive torque adjustment, improving control response speed, and consequently enhancing energy efficiency.

[0061] In one implementation, step S1, determining the current operating stage of the construction machinery, includes:

[0062] Acquire pilot control signal data from the actuators of construction machinery;

[0063] Based on the pilot control signal data, the current operating condition stage of the construction machinery is identified using a pre-trained operating condition stage identification model, and the current operating condition stage of the construction machinery is determined.

[0064] Among them, pilot control signal data refers to signal data generated before the actions of the actuator during operation, such as current or voltage signals output from the gantry controller to the multi-way valve, and pilot pressure signals from the multi-way valve. This data source can utilize signals such as actuator displacement, tilt angle, and hydraulic pump flow to achieve the purpose of identifying the working condition stage. Taking the six working condition stages in the dumping operation of a hydraulic excavator as an example, numbers 1-6 can be used to represent digging preparation, digging, hoisting slewing, unloading, empty bucket return, and idling, respectively. The pilot control signal data of the actuator is used as the flag for working condition stage identification and input into the pre-trained working condition stage identification model. When the output result is any of 1-6, it indicates that the current working condition stage is digging preparation, digging, hoisting slewing, unloading, empty bucket return, or idling. Afterwards, it is determined whether the working condition stage identification process has ended. If not, the data furthest from the current moment in the pilot control signal data is removed, and the pilot control signal data for the next moment is added, continuing the identification of the next working condition stage until the identification process ends. When the construction machinery is in operation, the identification process of the working condition stage is considered not to be over.

[0065] In one embodiment, based on pilot control signal data and a pre-trained operating condition stage identification model, the current operating condition stage of the construction machinery is identified to determine the current operating condition stage of the construction machinery, including:

[0066] The system collects pilot control signal data of the actuator within a certain time range from the current time; optionally, the pilot control signal data is collected via a CAN bus. The actuator includes the boom, stick, bucket, and swing motor coupling.

[0067] The pilot control signal data is preprocessed by means filtering to reduce noise and transient interference; the data sampling frequency is reduced by system sampling; and the time-domain feature values ​​of the reduced-frequency pilot control signal data are extracted to form a feature vector, as shown in Equation (1):

[0068] X=[x1,x2,x3,x4,x5,x6,x7,x8] (1)

[0069] In the formula: X is the eigenvector constructed based on the time domain eigenvalues; x1-x4 are the mean values ​​of the pilot control signals of the boom, stick, bucket, and swing motor working combination, respectively; x5-x8 are the variances of the pilot control signals of the boom, stick, bucket, and swing motor working combination, respectively.

[0070] The constructed feature vectors x1-x8 are normalized respectively, as shown in equation (2):

[0071]

[0072] In the formula: x new x represents the normalized eigenvalues; x represents the eigenvalues ​​before normalization; x max x represents the maximum value of the category feature corresponding to x in the feature vector; min This represents the minimum value of the category feature value corresponding to x in the feature vector;

[0073] The normalized feature vector is input into the working condition stage identification model;

[0074] The current operating condition stage is determined based on the model's output.

[0075] In one embodiment, the method further includes: training a working condition phase identification model. Training the working condition phase identification model includes:

[0076] The corresponding actuator pilot control signal waveforms for each operating condition stage are used as operating condition stage identification markers. The operating condition stages corresponding to each identification marker are represented. The pilot control signal waveforms and their corresponding operating condition stages are used as a set of data to construct the sample space for training the model.

[0077] The working condition stage recognition model is trained by using the pilot control signal waveform in the sample space as the input of the model to be trained and the corresponding working condition stage as the output of the model to be trained. The model parameters are adjusted to obtain the working condition stage recognition model.

[0078] Taking the dumping operation of a hydraulic excavator as an example, the pilot control signal waveforms of the actuators corresponding to the six stages of the dumping operation are used as identification markers for the operation stages. Numbers 1-6 represent the corresponding operation stages: digging preparation, digging, hoisting and slewing, unloading, empty bucket return, and idle operation. An excavator operation stage identification model is established based on LIBSVM (an open-source machine learning library for Support Vector Machines (SVM)). The pilot control signal waveforms in the sample space are used as model input, and the corresponding operation stage is used as model output. Model parameters are adjusted to maximize the model's identification accuracy. Optionally, the machine learning model used to train the operation stage identification model only needs to meet the conditions of reducing data processing volume, lowering model computing power requirements, and ensuring the accuracy of model results; it is not limited to the model described above.

[0079] In one embodiment, before determining the target speed range of the engine based on the operating condition stage in step S2, the method further includes the following steps:

[0080] Obtain operational test data at different working conditions and stages;

[0081] The engine speed distribution frequency corresponding to different operating conditions is obtained based on the operational test data.

[0082] Gaussian distribution fitting was performed on the engine speed distribution frequency corresponding to different operating conditions to obtain the fitting results;

[0083] Based on the rotational speed data within a preset range on both sides of the Gaussian distribution mean in the fitting results, the target rotational speed range corresponding to each operating condition stage is set.

[0084] This process involves extensive real-vehicle testing of engineering machinery to obtain engine speed distribution frequency histograms under different operating conditions. Next, the engine speed distribution frequency is determined based on the engine speed distribution frequency histograms. A Gaussian distribution is then fitted to the engine speed distribution frequency under different operating conditions, and the mean and variance of the Gaussian distribution are obtained as the fitting results. To ensure stable engine operation and fuel economy, for the speed data exhibiting a Gaussian distribution in each operating condition, speed data within a preset range on both sides of the Gaussian distribution mean are selected. For example, speed data within a 2σ range on both sides of the Gaussian distribution mean can be retained according to the 2σ principle, rounded, and set as the speed range for each operating condition.

[0085] The rationality of the engine's operating point setting at each operating stage is crucial for ensuring the effectiveness of phased energy management in construction machinery. Firstly, stable control of the operating point is achieved through real-time adjustment of the hydraulic pump displacement. The operating point setting must not only meet the load's power requirements but also ensure the construction machinery's operational efficiency, i.e., minimizing variations in the hydraulic pump's output flow rate across different operating stages. Secondly, the engine's power demand is typically time-varying within each operating stage and between different operating stages; setting a fixed, discrete operating point cannot achieve dynamic optimization. Finally, because the engine's speed regulation characteristic curve has a large absolute negative slope, small fluctuations in speed will cause large variations in torque. Combined with the universal characteristic curve, these large torque variations will further significantly impact engine fuel economy. Therefore, the speed range setting method in this application is more reasonable, achieving dynamic optimization of the operating point while ensuring operational efficiency.

[0086] Optionally, please combine Figure 2 After determining the target speed range of the engine based on the operating condition stage in step S2, the method further includes:

[0087] When the actual engine speed is not within the target speed range, the actual engine speed is adjusted based on the principle of maximum acceleration to bring the actual engine speed closer to the target speed range.

[0088] Specifically, adjusting the actual engine speed based on the principle of maximum acceleration includes:

[0089] When the actual engine speed is higher than the upper limit of the target speed range, the displacement of the hydraulic pump is increased to increase the speed and reduce the acceleration, thereby reducing the actual engine speed.

[0090] When the actual engine speed is lower than the lower limit of the target speed range, the displacement of the hydraulic pump is reduced to increase the speed and increase the acceleration, thereby increasing the actual engine speed.

[0091] In the power transmission process between the engine and the hydraulic pump, the hydraulic pump absorbs torque T. P for:

[0092]

[0093] In the formula, p1 and p2 are the outlet pressures of the front and rear pumps, respectively, in Pa; V m1 V m1 η1 represents the front and rear pump displacements, in ml / r; η2 represents the engine mechanical efficiency; and η3 represents the hydraulic pump efficiency.

[0094] The engine speed acceleration α is:

[0095]

[0096] In the formula: J is the equivalent rotational inertia of the engine and load, kg·m 2 .

[0097] When the engine's torque demand increases, the speed acceleration increases instantaneously in the opposite direction. The engine's fuel injection quantity passively increases to improve output torque, and the speed undergoes a gradual decrease in acceleration. This prolonged transition significantly reduces the operating speed of the construction machinery under high torque demand. Conversely, when the engine's torque demand decreases, the speed acceleration increases instantaneously in the positive direction. The engine's fuel injection quantity passively decreases to reduce output torque, and the speed undergoes a gradual increase in acceleration. This prolonged transition significantly reduces the operational smoothness of the construction machinery under low torque demand. Therefore, when the engine's actual speed is not within the target speed range, the maximum acceleration principle is used to adjust the engine speed. By adjusting the current controlled by the secondary pressure reducing valve of the hydraulic pump to change the hydraulic pump's displacement, the torque absorbed by the hydraulic pump is adjusted, and the engine speed adjustment acceleration is changed. This allows the engine operating point to quickly stabilize near the target speed range, shortening the speed adjustment time and improving the operational performance of the construction machinery. The specific process is as follows:

[0098] Scenario 1: When the engine transitions from a high target speed to a low target speed, if the actual engine speed is higher than the upper limit of the target speed range, increase the control current of the secondary pressure reducing valve of the hydraulic pump, i.e., increase the displacement V of the hydraulic pump. m and absorbed torque T P Increase the rotational speed and decrease the acceleration α so that the engine speed can be quickly reduced to near the upper limit of the target speed range; optionally, the control current of the secondary pressure reducing valve can be adjusted to the maximum value. If the identification process is not completed after adjusting the control current at the current moment, return to step S1 and re-determine whether the actual speed of the engine is within the target speed range.

[0099] Scenario 2: When the engine transitions from a low target speed to a high target speed, if the actual engine speed is lower than the lower limit of the target speed range, reduce the control current of the secondary pressure reducing valve, i.e., reduce the displacement V of the hydraulic pump. m and absorbed torque T P Increase the rotational speed to increase the acceleration α, so that the engine speed is rapidly increased to near the lower limit of the target speed range; optionally, the control current of the secondary pressure reducing valve can be adjusted to the minimum value. If the identification process is not completed after adjusting the control current at the current moment, return to step S1 and re-determine whether the actual speed of the engine is within the target speed range.

[0100] In the above process, speed adjustment is used to achieve rapid switching of engine speed, especially during transitions between operating conditions. During this rapid speed switching, the engine torque is also rapidly adjusted. When the actual speed reaches the target speed range, torque adjustment is switched to further optimize the engine torque, i.e., steps S3-S4 are executed. In other words, both the speed adjustment process based on the maximum acceleration principle and the torque adjustment process in steps S3-S4 can achieve the optimal torque setting for the engine in its current state (whether the speed is within or outside the target speed range) by adjusting the displacement of the hydraulic pump.

[0101] Optionally, in step S3, the preset energy-saving conditions include minimizing the engine's instantaneous fuel consumption rate. Under the constraints of the target speed range and required power, the target torque for controlling the engine that satisfies the preset energy-saving conditions is determined, including:

[0102] Obtain the target torque range corresponding to the target speed range;

[0103] Under the constraints of the target speed range, target torque range, and required power, the target torque for controlling the engine that meets the preset energy-saving conditions is determined.

[0104] The purpose of determining the target torque is to optimize the engine output torque by adjusting the displacement of the hydraulic pump within the target speed range that meets the power demand and the operating conditions, so that the operating point is close to or in the fuel-efficient range, thereby reducing energy consumption.

[0105] Taking the determination of the engine's target torque using a genetic algorithm as an example, the design variables for optimizing torque using the genetic algorithm are:

[0106] x=(n,T) (6)

[0107] In the formula, n is the engine speed, r / min; T is the engine output torque, N·m;

[0108] The objective function is:

[0109] minF(x)=g oil (n,T) (7)

[0110] Where: g oil This is the instantaneous fuel consumption rate function of the engine.

[0111] The constraints are:

[0112]

[0113] In the formula: P predict n represents the power demand at the next moment. lowThis represents the lower limit of the target speed range; n up T represents the upper limit of the target speed range. low The lower limit of the target torque range; T up This represents the upper limit of the target torque range.

[0114] Genetic algorithms can employ a non-linear ranking selection method similar to roulette wheel selection, setting the number of generations, the total number of individuals, crossover, and mutation coefficients. They can then calculate the optimal engine torque corresponding to the lowest fuel consumption rate under the constraints of the required power and target speed range at the next moment, thereby obtaining the target torque.

[0115] It is understandable that genetic algorithms require less computing power. Depending on the computing power level of engineering machinery, other suitable algorithms can also be selected to determine the target torque of the engine.

[0116] To reduce the energy consumption of construction machinery engines, the multi-level decision-making process for achieving global optimal fuel economy is decomposed into a series of individual decision-making processes. In each individual decision-making process, the hydraulic pump displacement is adjusted based on the operating condition and load power demand of the construction machinery to bring the engine operating point closer to the fuel-efficient zone. When employing the dynamic programming control strategy described above, it is necessary to obtain the power demand at the next moment. Optionally, when the actual engine speed is within the target speed range, the power demand at the next moment can be considered essentially unchanged from the current moment, thus using a corresponding fixed power as the power demand at the next moment for different operating conditions. Optionally, considering the significant periodicity of engine power demand at different operating conditions, power prediction can also be used to determine the power demand at the next moment to improve accuracy.

[0117] Optionally, in step S3, when the actual engine speed is within the target speed range, the required engine power at the next moment is obtained, including:

[0118] When the actual engine speed is within the target speed range, acquire the working data corresponding to the current moment and a preset number of moments before the current moment.

[0119] Based on the working data, and using a pre-trained engine demand power prediction model, the engine demand power at the next moment is predicted.

[0120] Optionally, the operating data may include front pump pressure, rear pump pressure, front pump feedback pressure, rear pump feedback pressure, engine speed, torque percentage data, and may also include actuator pilot control signals, displacement, tilt angle, hydraulic pump flow, and other signals.

[0121] Optionally, based on the front pump pressure, rear pump pressure, front pump feedback pressure, rear pump feedback pressure, engine speed, and torque percentage data, the engine's power demand at the next moment is predicted, including the following steps:

[0122] Data on the front pump pressure, rear pump pressure, front pump feedback pressure, rear pump feedback pressure, engine speed, and torque percentage of the construction machinery are collected via CAN bus at a distance of n from the current time.

[0123] Construct the feature vector according to the form of equation (9):

[0124]

[0125] In the formula, y 1,n This is the pressure signal from the front pump; y 2,n This is the pressure signal from the rear pump; y 3,n For the front pump feedback pressure signal; y 4,n For the feedback pressure signal of the rear pump; y 5,n For engine speed signal; y 6,n is the engine torque signal; n is the amount of data within the time window.

[0126] The eigenvectors are then normalized using equation (2).

[0127] The normalized feature vector is input into the engine demand power prediction model, and the model output is the engine demand power at the next moment.

[0128] The process of predicting engine power demand is determined to be complete. If not, the data furthest from the current moment in the feature vector is removed, and the data for the front pump pressure, rear pump pressure, front pump feedback pressure, rear pump feedback pressure, engine speed, and torque percentage for the next moment are added. This prediction process is repeated until the prediction process ends. Optionally, the prediction process is considered incomplete when the construction machinery is in operation.

[0129] Optionally, the method also includes: training an engine demand power prediction model;

[0130] Training the engine demand power prediction model includes:

[0131] Acquire test data and engine output power at different operating conditions and corresponding times;

[0132] The test data, which is extracted from a preset number of time windows, and the engine output power at the next time window represented by the rightmost time window are used as a set of data to construct the sample data for training the model.

[0133] The test data from each set of data is used as the input to the model to be trained, and the engine output power from each set of data is used as the output of the model to be trained. The model parameters are adjusted to train the engine demand power prediction model.

[0134] Among these efforts, extensive real-vehicle operation tests of construction machinery were conducted to obtain a large amount of data on the front pump pressure, rear pump pressure, front pump feedback pressure, rear pump feedback pressure, engine speed, torque percentage, and engine output power at the corresponding time.

[0135] Next, a time window is used to extract data on the front pump pressure, rear pump pressure, front pump feedback pressure, rear pump feedback pressure, engine speed, and torque percentage of length n. The model input vector is constructed according to Equation (9) and normalized with reference to Equation (2) to obtain the test working data as the model input. The engine output power at the next moment, represented by the rightmost moment of the time window, is used as the model output. The model input and corresponding output form a set of data to construct the sample space for training the model.

[0136] Subsequently, an engine demand power prediction model based on Long Short-Term Memory (LSTM) network was designed. The normalized matrix consisting of front pump pressure, rear pump pressure, front pump feedback pressure, rear pump feedback pressure, engine speed, and torque percentage data in the sample space was used as the model input, and the corresponding engine output power was used as the model output. The model parameters were adjusted to minimize the root mean square error of the model output, thereby training the engine demand power prediction model.

[0137] Optionally, after determining the target torque for controlling the engine that meets the preset energy-saving conditions under the constraints of the target speed range and required power in step S4, the method further includes:

[0138] The hydraulic pump displacement is controlled according to the target torque;

[0139] Controlling the hydraulic pump displacement based on the target torque includes:

[0140] The change in outlet pressure of the secondary pressure reducing valve of the hydraulic pump is determined based on the deviation between the target torque and the actual torque of the engine.

[0141] The control current of the secondary pressure reducing valve of the hydraulic pump is determined based on the change in outlet pressure in order to control the displacement of the hydraulic pump.

[0142] The engine's load torque is jointly determined by the torque absorbed by the hydraulic pump and auxiliary equipment. Assuming that the torque absorbed by the auxiliary equipment remains constant in a short time, a fuzzy control algorithm with high real-time performance and strong robustness is adopted based on recursion. The deviation between the optimal torque (target torque) at the next moment and the engine torque at the current moment, as well as the rate of change of the deviation, are used as model inputs, and the change in outlet pressure of the secondary pressure reducing valve of the hydraulic pump is used as model output, as detailed below:

[0143]

[0144] In the formula: E is the deviation; EC is the change in deviation; For E, take the derivative with respect to time t; T next (t+1) represents the optimal torque at the next moment; T(t) represents the engine torque at the current moment; T P The hydraulic pump absorbs torque; ΔP next This represents the change in outlet pressure of the secondary pressure reducing valve.

[0145] After fuzzy control, the outlet pressure of the secondary pressure reducing valve of the hydraulic pump at the next moment is:

[0146] P i (t+1)=P i (t)+ΔP next (11)

[0147] In the formula: P i (t) represents the outlet pressure of the secondary pressure reducing valve at the current moment.

[0148] This achieves optimized adjustment of the operating point for different operating conditions, resulting in good energy-saving performance.

[0149] Considering the obvious periodicity of the operating patterns and loads of the actuators in construction machinery, the method of setting the engine operating point using a fixed operating mode and gear is highly subjective and cannot achieve real-time optimal energy consumption. Therefore, the method of this application has the following technical advantages:

[0150] (1) A working condition stage identification method based on the pilot control signal of the actuator is proposed. The signal source belongs to the hydraulic system command signal and has high real-time performance. In addition, the inputs are all signal sources already configured by the host. The selection of neural network and signal frequency reduction make it low in cost and low in computing power requirement, making it more suitable for the host configuration of engineering machinery.

[0151] (2) Based on extensive real vehicle test results, Gaussian distribution is used to fit the speed distribution law of each working stage, and the target speed range of each working stage based on the 2σ principle is formulated. This not only ensures the working efficiency of the construction machinery, but also the interval form of the target speed setting method can achieve dynamic optimization of energy consumption.

[0152] (3) An engine speed adjustment strategy based on the principle of maximum acceleration is proposed. During the transition of engineering machinery operating conditions, the hydraulic pump displacement is changed by adjusting the control current of the secondary pressure reducing valve of the hydraulic pump, thereby adjusting the torque absorbed by the hydraulic pump and changing the engine speed adjustment acceleration, so that the engine operating point can be quickly stabilized to near the target value, shortening the speed adjustment time and improving the excavator operation performance.

[0153] (4) Based on the idea of ​​dynamic programming control of the global optimal fuel economy of construction machinery, an engine demand power prediction method is proposed. Considering that the operation process of construction machinery and the engine demand power have obvious periodicity, an LSTM deep learning model that can handle the long-term dependence of sequential data is adopted. The input vector is constructed by the original data of front and rear pump pressure, front and rear pump feedback pressure, engine speed and torque percentage. The model parameters are adjusted to achieve accurate prediction of engine demand power.

[0154] (5) A torque adjustment strategy based on genetic algorithm optimization is proposed. When the actual engine speed reaches the target speed range, within the range of the predicted engine power demand and the target speed allowed by the working condition stage, the hydraulic pump displacement is further adjusted through genetic algorithm to optimize the engine output torque, so that the working point is close to the economic fuel zone and the energy consumption level is reduced.

[0155] (6) Considering the existence of the auxiliary equipment's absorbed torque, the optimal torque fuzzy controller is designed with the deviation between the optimal torque at the next moment and the engine torque at the current moment, as well as the rate of change of the deviation, as the model input, and the change of the outlet pressure of the hydraulic pump's secondary pressure reducing valve as the model output, resulting in higher control accuracy.

[0156] (7) Based on the pilot control signal, the real-time performance of the operating condition stage is higher. By predicting the engine's power demand at the next moment, the adjustment of the operating point is an active adjustment, which can improve the host response speed and energy saving effect.

[0157] The control method for construction machinery disclosed in this application determines the current operating stage of the construction machinery, determines the target speed range of the engine based on the operating stage, and obtains the engine's required power at the next moment when the actual engine speed is within the target speed range. Under the constraints of the target speed range and the required power, a target torque for controlling the engine that meets preset energy-saving conditions is determined. The technical solution of this application sets target speed ranges corresponding to different operating stages, and determines the torque that meets the energy-saving conditions and the required power at the next moment based on the target speed range. This allows the operating point of the engine to be adjusted based on the corresponding speed range for different operating stages, and the operating point of the engine in the same operating stage can also be adjusted according to the required power. Therefore, the engine operating point can be dynamically adjusted in different operating stages and in the same operating stage, achieving dynamic optimization of energy consumption and good energy-saving effect.

[0158] like Figure 3 As shown, this application also provides a piece of construction machinery, which includes an engine 31 and a control device 33, the control device 33 being configured to:

[0159] Determine the current operating stage of the construction machinery;

[0160] Determine the target speed range of the engine based on the operating conditions.

[0161] When the actual engine speed is within the target speed range, obtain the engine's required power at the next moment;

[0162] Under the constraints of the target speed range and required power, the target torque for controlling the engine that meets the preset energy-saving conditions is determined.

[0163] The steps and other steps performed by the control device are the same as those in the above-described method embodiments, and will not be repeated here.

[0164] This application also provides an electronic device, including a processor, a memory, and a computer program stored in the memory and executable on the processor, wherein the computer program, when executed by the processor, implements the steps of the method described above.

[0165] This application also provides a computer-readable storage medium on which a computer program is stored, which, when executed by a processor, implements the steps of the method described above.

[0166] The above description is merely a specific embodiment of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the appended claims.

Claims

1. A control method for engineering machinery, characterized in that, The engineering machinery includes an engine, and the method includes: Determine the current operating stage of the construction machinery; The target speed range of the engine is determined based on the operating condition stage; When the actual speed of the engine is within the target speed range, obtain the required power of the engine at the next moment; Under the constraints of the target speed range and the required power, a target torque for controlling the engine is determined that meets preset energy-saving conditions, including the lowest instantaneous fuel consumption rate of the engine.

2. The method as described in claim 1, characterized in that, Determining the current operating stage of the construction machinery includes: Acquire pilot control signal data from the actuators of construction machinery; Based on the pilot control signal data, the current operating stage of the construction machinery is identified using a pre-trained operating stage identification model, and the current operating stage of the construction machinery is determined.

3. The method as described in claim 1, characterized in that, Before determining the target speed range of the engine based on the operating condition stage, the method further includes: Obtain operational test data at different working conditions and stages; Based on the operational test data, obtain the engine speed distribution frequency corresponding to different operating conditions. Gaussian distribution fitting was performed on the engine speed distribution frequency corresponding to the different operating conditions to obtain the fitting results; Based on the rotational speed data within a preset range on both sides of the Gaussian distribution mean in the fitting results, the target rotational speed range corresponding to each operating condition stage is set.

4. The method according to any one of claims 1 to 3, characterized in that, The construction machinery also includes a hydraulic pump connected to the engine. After determining the target speed range of the engine based on the operating condition stage, the method further includes: When the actual speed of the engine is higher than the upper limit of the target speed range, the displacement of the hydraulic pump is increased to increase the speed and reduce the acceleration, thereby reducing the actual speed of the engine. When the actual speed of the engine is lower than the lower limit of the target speed range, the displacement of the hydraulic pump is reduced to increase the speed and increase the acceleration, thereby increasing the actual speed of the engine.

5. The method as described in claim 1, characterized in that, Determining the target torque for controlling the engine, which satisfies preset energy-saving conditions, under the constraints of the target speed range and the required power, includes: Obtain the target torque range corresponding to the target speed range; Under the constraints of the target speed range, the target torque range, and the required power, a target torque for controlling the engine that meets preset energy-saving conditions is determined.

6. The method as described in claim 1 or 5, characterized in that, The step of obtaining the engine's required power at the next moment when the actual engine speed is within the target speed range includes: When the actual speed of the engine is within the target speed range, acquire the working data corresponding to the current moment and a preset number of moments before the current moment; Based on the working data, and using a pre-trained engine demand power prediction model, the engine's demand power at the next moment is predicted.

7. The method as described in claim 6, characterized in that, The method further includes: training the engine demand power prediction model; The training of the engine demand power prediction model includes: Acquire test data and engine output power at different operating conditions and corresponding times; The test data of a preset number of moments captured by the time window, and the engine output power of the moment after the latest moment of the time window are used as a set of data to construct the sample data for training the model. The test data from each set of data is used as the input to the model to be trained, and the engine output power from each set of data is used as the output of the model to be trained. The model parameters are adjusted to train the engine demand power prediction model.

8. The method as described in claim 1, characterized in that, The construction machinery also includes a secondary pressure reducing valve for the hydraulic pump. After determining the target torque for controlling the engine that meets preset energy-saving conditions under the constraints of the target speed range and the required power, the method further includes: The change in outlet pressure of the secondary pressure reducing valve of the hydraulic pump is determined based on the deviation between the target torque and the actual torque of the engine. The control current of the secondary pressure reducing valve of the hydraulic pump is determined based on the change in outlet pressure, so as to control the displacement of the hydraulic pump of the engine.

9. A type of construction machinery, the construction machinery comprising an engine and a control device, characterized in that, The control device is configured to: Determine the current operating stage of the construction machinery; The target speed range of the engine is determined based on the aforementioned operating conditions. When the actual speed of the engine is within the target speed range, obtain the required power of the engine at the next moment; Under the constraints of the target speed range and the required power, a target torque for controlling the engine is determined that meets preset energy-saving conditions, including the lowest instantaneous fuel consumption rate of the engine.

10. An electronic device, characterized in that, It includes a processor, a memory, and a computer program stored in the memory and executable on the processor, wherein the computer program, when executed by the processor, implements the steps of the method as described in any one of claims 1 to 8.

11. A computer-readable storage medium, characterized in that, A computer program is stored on the computer-readable storage medium, which, when executed by a processor, implements the steps of the method as described in any one of claims 1 to 8.

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