Hydraulic driving device of corn harvester

Abstract

The invention discloses a hydraulic driving device of a corn harvester, and particularly relates to the field of vehicle transmission systems based on hydraulic driving and self-adaptive control, and the hydraulic driving device comprises a hydraulic driving module, a virtual load module, a difference calculation module and an energy management module; the hydraulic driving module comprises a driving wheel hydraulic motor, a load sensor, a pressure sensor, an oil cavity energy accumulator and a control valve group; the driving wheel hydraulic motor is installed at the position close to the driving wheel and connected with the hydraulic loop. The load sensor and the pressure sensor are connected to the controller through an acquisition channel and output real-time load parameters. A virtual load curve is constructed and combined with a difference calculation module to generate an energy storage control instruction, and then an energy management and self-adaptive release module restrains and adjusts the energy charging and releasing process of an oil cavity energy accumulator so as to restrain the speed instability and torque reversal of a hydraulic driving execution component when the load drops suddenly.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of vehicle transmission system based on hydraulic drive and adaptive control, and more particularly, to a hydraulic drive device of a corn harvester. BACKGROUND

[0002] In the constant speed control technology of the existing hydraulic drive harvester, the system generally relies on pressure feedback to maintain the speed stability of the execution component; when the working environment is under the condition of regular terrain and uniform crop density, such control logic can better guarantee the continuity of cutting and conveying; However, in complex scenes such as slope or wetland, the crop density and resistance are not constant, for example, when the header enters the empty area or encounters sudden resistance drop, the pressure feedback of the hydraulic system will instantaneously decrease; under the assumption of traditional logic, the load drop is usually regarded as a favorable situation, but the actual situation is just the opposite: the sudden pressure drop triggers the excessive torque release of the hydraulic servo, causing the speed of the execution component to rise nonlinearly in a very short time; This "speed and torque reversal" not only directly destroys the uniform cutting effect of crops, but also causes strong impact in the oil return pipeline, resulting in pump cavitation and system fatigue damage; as can be seen, the existing constant speed control lacks a forward-looking constraint mechanism when dealing with terrain disturbances and load drops; the core problem lies in that it mistakenly equates load drop to system burden reduction, ignoring the speed instability and structural risks caused thereby. SUMMARY

[0003] In order to overcome the above-mentioned defects of the prior art, the embodiments of the present application provide a hydraulic drive device of a corn harvester, which generates an energy storage control instruction by constructing a virtual load curve and combining a difference calculation module, and then constrains and adjusts the charging and releasing process of the oil cavity accumulator by an energy management and adaptive release module, so as to inhibit the speed instability and torque reversal of the hydraulic drive execution component when the load drops; to solve the problems raised in the background art.

[0004] To achieve the above-mentioned purpose, the present application provides the following technical scheme: a hydraulic drive device of a corn harvester, comprising a hydraulic drive module, a virtual load module, a difference calculation module and an energy management module; The hydraulic drive module comprises a drive wheel hydraulic motor, a load sensor, a pressure sensor, an oil cavity accumulator and a control valve group; the drive wheel hydraulic motor is installed at a position close to the drive wheel and is connected with the hydraulic circuit; the load sensor and the pressure sensor are connected to the controller through a collection channel and output real-time load parameters; the oil cavity accumulator is connected in parallel between the oil inlet branch and the oil return branch of the drive wheel hydraulic motor through the control valve group and responds to the control instruction to perform energy absorption and energy release; the control valve group comprises a one-way stop valve and a proportional control valve; The virtual load module is used to call the real-time load parameters, generate a virtual load curve, and construct a constant resistance reference benchmark; The difference calculation module is used to perform difference calculation between the real-time load parameters and the virtual load curve, solve the load difference signal and generate energy storage control instructions. The energy storage control instructions are used to control the upper limit of the charging process, the upper limit of the releasing process and the upper limit of the energy change rate. The energy management module is used to call the oil chamber accumulator and perform a charging action when the load decreases according to the energy storage control command, so as to limit the speed change rate of the hydraulic drive actuator within a preset threshold range.

[0005] In a preferred embodiment, the system further includes an adaptive release module; the adaptive release module generates a predicted release curve based on the time series of the load difference signal and the virtual load curve, calls the oil chamber accumulator to output an energy release command according to the predicted release curve and injects energy into the hydraulic servo, and controls the angular velocity of the hydraulic drive actuator to be within a preset threshold range.

[0006] In a preferred embodiment, the execution of the virtual load module includes: The load sensor in the hydraulic drive module is called to generate crop resistance data, the pressure sensor is called to generate hydraulic pressure data, and the rotational speed data output by the hydraulic motor of the drive wheel is called to generate real-time load parameters. The real-time load parameters are normalized to form crop resistance sequence, hydraulic pressure sequence and rotation speed sequence, and the parameter correspondence is established. In the parameter correspondence, the hydraulic pressure sequence is matched one-to-one with the speed sequence according to the time index, the speed change rate and pressure change rate per unit time are calculated, and the ratio of the speed change rate to the pressure change rate is used as the speed-pressure coupling factor. The volatility of the crop resistance sequence is weighted and superimposed with the velocity-pressure coupling factor to generate a virtual load curve, which corresponds to the theoretical reference curve under constant resistance conditions. The current state data of the oil chamber accumulator and the control valve group are called up, and the virtual load curve is combined with the charging state of the oil chamber accumulator and the opening state of the control valve group to construct a constant resistance reference benchmark.

[0007] In a preferred embodiment, the execution of the difference calculation module includes: The real-time load parameters and the virtual load curve are compared point by point under a unified preset time index to generate an initial set of differences. The initial difference set is subjected to three layers of screening in sequence. The first layer of screening is based on whether the fluctuation amplitude of crop resistance data exceeds the upper and lower limits of a preset threshold. The second layer of screening is based on whether the rate of change of hydraulic pressure data is within the allowable range. The third layer of screening is based on whether the phase difference between rotation speed data and hydraulic pressure data is maintained within a preset synchronization range. When any layer of screening result does not meet the conditions, the corresponding difference is returned and the data of the previous time window of the virtual load curve is called again to form a corrected difference. The corrected difference is cross-mapped with the coupling ratio of the speed data and hydraulic pressure data. The coupling ratio represents the ratio of the rate of change of speed to the rate of change of hydraulic pressure calculated under a unified time index. The cross-mapping includes performing three types of operations simultaneously at each time point: the first type of operation includes multiplying the corrected difference with the coupling ratio to generate a product sequence; the second type of operation includes dividing the corrected difference by the coupling ratio to generate a ratio sequence; and the third type of operation includes subtracting the corrected difference from the coupling ratio to generate a difference sequence. The product sequence, ratio sequence, and difference sequence are combined according to the time index to form a three-dimensional cross-difference matrix.

[0008] In a preferred embodiment, the execution of the difference calculation module further includes: The three-dimensional cross difference matrix is ​​iterated repeatedly. Each iteration is corrected by combining the charging state of the oil chamber accumulator with the opening state of the control valve group. When the iteration result deviates from the preset reference range, the previous iteration value is returned to the initial difference set and re-entered for calculation until the final load difference signal that meets the convergence condition is generated. Based on the final load difference signal, an energy storage control command is output. The energy storage control command is used to control the upper limit of the charging process, the upper limit of the releasing process, and the upper limit of the energy change rate.

[0009] In a preferred embodiment, the execution of the energy management module includes: Receive the energy storage control command generated by the difference calculation module and invoke the oil cavity accumulator; When the load decreases and falls below a preset threshold, the oil chamber accumulator is controlled to perform a charging action according to the energy storage control command, storing the pressure energy in the hydraulic circuit in the oil chamber accumulator. During the charging process, the speed change rate of the hydraulic drive actuator is monitored and compared with a preset threshold range. When the speed change rate tends to exceed the preset threshold range, the charging rate of the oil chamber accumulator is adjusted to keep the speed change rate within the preset threshold range.

[0010] In a preferred embodiment, the execution of the adaptive release module includes: Under a unified preset time index, the time series of the load difference signal and the virtual load curve are called. The load difference value and the virtual load value at the same time point are subtracted to form a time series difference set. At each time point, the adjacent difference values ​​are subtracted to calculate the local change rate. Then, each local change rate is interpolated in time order to form a continuous change curve to generate a predicted release curve. Based on the value of the predicted release curve at each time point, an energy release command is generated, and the oil chamber accumulator is invoked. The oil chamber accumulator is controlled to release oil at a corresponding flow rate when the value of the predicted release curve is higher than zero, and to remain closed when the value of the predicted release curve is lower than zero, so as to realize the segmented injection of energy. During the execution of the energy release command, the angular velocity of the hydraulically driven actuator is continuously collected, and the difference in angular velocity between adjacent moments is calculated to obtain the rate of change of angular velocity. The rate of change of angular velocity is compared with a preset threshold range. When the comparison result shows that the rate of change of angular velocity exceeds the threshold range, the release rate of the oil chamber accumulator is adjusted, and the flow rate is redefined by changing the opening of the control valve group, so that the angular velocity of the hydraulically driven actuator is kept within the preset threshold range.

[0011] The technical effects and advantages of this invention are as follows: This solution, through the synergistic effect of the differential calculation module and the energy management module, does not directly reduce the output when the load decreases, but instead triggers the oil chamber accumulator to perform charging and rate constraint, so that the hydraulic drive actuators avoid speed and torque reversal caused by sudden pressure drop, thereby suppressing the speed instability and return oil shock problems of the actuators. The virtual load module of this solution constructs a virtual load curve and forms a constant resistance reference benchmark by serializing crop resistance, hydraulic pressure and rotation speed, thereby realizing dynamic mapping of real load fluctuations and enabling the drive process to have steady-state constraint capability independent of single pressure feedback. The difference calculation module of this scheme performs step-by-step correction and convergence calculation on the difference through a three-layer screening and three-dimensional cross difference matrix iterative mechanism, ensuring that the final load difference signal has multi-dimensional constraint characteristics, thereby making the generation of energy storage control commands stable and robust. The energy management module of this solution monitors the speed change rate of the hydraulically driven actuators in real time when performing the charging action, and maintains the speed change rate within a preset threshold range by dynamically adjusting the charging rate of the accumulator, thereby reducing the risk of speed fluctuations caused by sudden changes in operation. The adaptive release module of this solution generates a predicted release curve based on the load difference signal and the virtual load curve, and regulates the energy release process of the accumulator accordingly. At the same time, it monitors and adjusts the angular velocity of the actuator to ensure that the energy release process is dynamically and highly matched with the working load, thereby achieving stable and continuous drive output. Attached Figure Description

[0012] Figure 1 This is a schematic diagram of the system module configuration of the device of the present invention. Detailed Implementation

[0013] 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 some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0014] Refer to the instruction manual appendix Figure 1 A hydraulic drive device for a corn harvester according to an embodiment of the present invention includes a hydraulic drive module, a virtual load module, a difference calculation module and an energy management module; The hydraulic drive module includes a drive wheel hydraulic motor, a load sensor, a pressure sensor, an oil chamber accumulator, and a control valve group. The drive wheel hydraulic motor is installed near the drive wheel and connected to the hydraulic circuit. The load sensor and pressure sensor are connected to the controller via a data acquisition path and output real-time load parameters. The oil chamber accumulator is connected in parallel between the inlet and return branches of the drive wheel hydraulic motor through the control valve group and performs energy absorption and release in response to control commands. The control valve group includes a one-way shut-off valve and a proportional control valve. The virtual load module is used to call the real-time load parameters, generate a virtual load curve, and construct a constant resistance reference benchmark; The difference calculation module is used to perform difference calculation between the real-time load parameters and the virtual load curve, solve the load difference signal and generate energy storage control instructions. The energy storage control instructions are used to control the upper limit of the charging process, the upper limit of the releasing process and the upper limit of the energy change rate. The energy management module is used to call the oil chamber accumulator and, according to the energy storage control command, to perform a charging action when the load decreases, thereby limiting the speed change rate of the hydraulic drive actuator within a preset threshold range. It should be noted that the execution process of the hydraulic drive module is as follows: the hydraulic motor of the drive wheel is fixed near the drive wheel and connected to the hydraulic circuit through the inlet and return oil branches. Under the action of control commands, it generates the rotational torque of the drive wheel; when the crop enters the header, the load sensor collects the resistance value of the crop acting on the working part in real time, and the pressure sensor simultaneously detects the hydraulic pressure value in the inlet and return oil branches. The above values ​​are transmitted to the controller through the acquisition channel and form real-time load parameters; after receiving the real-time load parameters, the controller generates corresponding control commands and transmits the control commands to the control valve group; the control valve group consists of a one-way shut-off valve and a proportional valve. The control valve assembly consists of a one-way shut-off valve to ensure the hydraulic oil flows in a predetermined direction, and a proportional control valve that adjusts the valve opening according to control commands to change the oil flow rate. Under the action of the control valve assembly, the oil chamber accumulator is connected in parallel with the inlet and return branches. When the real-time pressure is higher than the threshold, the proportional control valve opening decreases to guide the oil into the oil chamber accumulator and perform the charging action. When the real-time pressure is lower than the threshold, the proportional control valve opening increases to guide the oil chamber accumulator to release the stored energy and re-inject the oil into the circuit. This achieves dynamic control of energy absorption and release throughout the process and ensures that the drive wheel hydraulic motor maintains stable operation under different working conditions. In addition, energy absorption refers to the process where, when the hydraulic circuit pressure is higher than the threshold, oil is introduced into the accumulator in the oil chamber and the internal medium is compressed, thereby storing excess hydraulic energy in the oil chamber. Energy release refers to the process where, when the hydraulic circuit pressure is lower than the threshold, the rebound of the medium inside the accumulator in the oil chamber pushes the oil back into the hydraulic circuit, thereby re-injecting the previously stored energy into the drive wheel hydraulic motor and related actuators. The two form a closed loop, which is used to balance the pressure fluctuations of the hydraulic system and maintain the continuity of the drive process.

[0015] It also includes an adaptive release module; the adaptive release module generates a predicted release curve based on the time series of the load difference signal and the virtual load curve, calls the oil chamber accumulator to output an energy release command according to the predicted release curve and injects energy into the hydraulic servo, and controls the angular velocity of the hydraulic drive actuator to be within a preset threshold range.

[0016] The execution of the virtual load balancer module includes: The load sensor in the hydraulic drive module generates crop resistance data, the pressure sensor generates hydraulic pressure data, and the rotational speed data output by the drive wheel hydraulic motor is used to generate real-time load parameters. The crop resistance data is the resistance value of the crop acting on the working component at the header or feed inlet, collected by the load sensor, reflecting the magnitude of the mechanical load generated when the crop enters. The hydraulic pressure data is the pressure value of the hydraulic circuit in the inlet and return branches of the drive wheel hydraulic motor, collected by the pressure sensor, reflecting the fluid pressure state of the hydraulic system under real-time operating conditions. The rotational speed data is the angular velocity value output by the drive wheel hydraulic motor, reflecting the rotational speed of the hydraulic drive actuator per unit time. The real-time load parameters are normalized to form crop resistance, hydraulic pressure, and rotational speed sequences, and a parameter correspondence is established. Normalization refers to mapping different dimensional values ​​of the real-time load parameters to a unified numerical range using the same transformation rule, ensuring comparability and consistency of crop resistance, hydraulic pressure, and rotational speed data during calculation. This includes performing linear scaling or dimensionless transformation based on a preset threshold range on the original values. Establishing the parameter correspondence involves matching the normalized crop resistance, hydraulic pressure, and rotational speed sequences one-to-one according to a unified time index, forming a set of associated parameters for subsequent calculations and analysis. In the parameter correspondence, the hydraulic pressure sequence is matched one-to-one with the speed sequence according to the time index, the speed change rate and pressure change rate per unit time are calculated, and the ratio of the speed change rate to the pressure change rate is used as the speed-pressure coupling factor. The volatility of the crop resistance sequence is weighted and superimposed with the velocity-pressure coupling factor to generate a virtual load curve, which corresponds to the theoretical reference curve under constant resistance conditions. It should be noted that in the weighted superposition process, firstly, the numerical fluctuation amplitude of the crop resistance sequence within a unit time window is calculated to form the crop resistance volatility; then, the ratio of the rate of change of the rotational speed sequence to the rate of change of the hydraulic pressure sequence is calculated to form the velocity-pressure coupling factor; next, the crop resistance volatility and the velocity-pressure coupling factor are multiplied by a preset weight ratio and summed to obtain the virtual load value at each time point; finally, the virtual load values ​​are arranged in a time series to generate a virtual load curve, which serves as the theoretical reference curve under constant resistance conditions. The current state data of the oil chamber accumulator and the control valve group are retrieved, and the virtual load curve is combined with the charging state of the oil chamber accumulator and the opening state of the control valve group to construct a constant resistance reference benchmark. In constructing the constant resistance reference benchmark, firstly, the charging state data of the oil chamber accumulator and the opening state data of the control valve group are retrieved and matched with the virtual load curve under the same time index. Then, based on the value of the virtual load curve, it is determined whether the charging energy of the oil chamber accumulator and the opening size of the control valve group need to be adjusted, forming a linkage relationship between the virtual load and the hardware state. Finally, the adjusted charging state and opening state are superimposed with the virtual load curve to generate a constant resistance reference benchmark used to constrain the operation of the hydraulically driven actuators. The current state data of the oil chamber accumulator refers to its pressure value and charging energy data under real-time operating conditions; the current state data of the control valve group refers to the opening position and flow channel state of the one-way shut-off valve and the proportional control valve under real-time operating conditions.

[0017] The execution of the difference calculation module includes: The real-time load parameters and the virtual load curve are compared point-by-point under a unified preset time index to generate an initial set of differences. During this point-by-point comparison, the real-time load parameters are first used to arrange crop resistance data, hydraulic pressure data, and rotational speed data in chronological order to form a time series. Then, the virtual load curve is used to arrange the virtual load values ​​according to the same preset time index to form a comparison sequence. At each time point, the value corresponding to the real-time load parameter is subtracted from the value of the virtual load curve to generate a single-point difference. All single-point differences are then combined in chronological order to form the initial set of differences. The initial difference set is subjected to three layers of screening in sequence. The first layer of screening is based on whether the fluctuation amplitude of crop resistance data exceeds the upper and lower limits of a preset threshold. The second layer of screening is based on whether the rate of change of hydraulic pressure data is within the allowable range. The third layer of screening is based on whether the phase difference between rotation speed data and hydraulic pressure data is maintained within a preset synchronization range. When any layer of screening result does not meet the conditions, the corresponding difference is returned and the data of the previous time window of the virtual load curve is called again to form a corrected difference. The corrected difference is cross-mapped with the coupling ratios of the speed data and hydraulic pressure data. The coupling ratio represents the ratio of the rate of change of speed to the rate of change of hydraulic pressure calculated under a unified time index. Specifically, at each time point, the difference in speed between adjacent time points is calculated and divided by the difference in hydraulic pressure between adjacent time points to form the coupling ratio at that time point. The cross-mapping includes performing three types of operations simultaneously at each time point: the first type of operation includes multiplying the corrected difference with the coupling ratio to generate a product sequence; the second type of operation includes dividing the corrected difference with the coupling ratio to generate a ratio sequence; and the third type of operation includes subtracting the corrected difference from the coupling ratio to generate a difference sequence. The product sequence, ratio sequence, and difference sequence are combined according to the time index to form a three-dimensional cross-difference matrix.

[0018] The execution of the difference calculation module also includes: The three-dimensional cross difference matrix is ​​iterated repeatedly. Each iteration is corrected by combining the charging state of the oil chamber accumulator with the opening state of the control valve group. When the iteration result deviates from the preset reference range, the previous iteration value is returned to the initial difference set and re-entered for calculation until the final load difference signal that meets the convergence condition is generated. Based on the final load difference signal, an energy storage control command is output. The energy storage control command is used to control the upper limit of the charging process, the upper limit of the releasing process, and the upper limit of the energy change rate. It should be noted that the three-layer screening is performed to ensure the validity and stability of the difference before generating the load difference signal: the first layer is based on the fluctuation range of crop resistance data to confirm that the resistance change is within a reasonable range; the second layer is based on the rate of change of hydraulic pressure data to confirm that the dynamic response of the system pressure does not exceed the allowable range; the third layer is based on the phase difference between the rotational speed data and the hydraulic pressure data to confirm that the speed and pressure of the actuator are synchronized. If any layer of screening fails, the difference is returned and the data from the previous time window of the virtual load curve is called again to form a corrected difference, thereby preventing outliers from directly entering subsequent calculations; on this basis, the ratio of the speed change rate to the hydraulic pressure change rate is introduced as a coupling ratio to reflect the dynamic coupling relationship between speed and pressure. The cross-mapping of the correction difference and coupling ratio includes three types of operations: multiplication to obtain the enhancement effect, calculation of the quotient to obtain the relative strength, and subtraction to obtain the degree of offset. The three types of operations output product sequences, ratio sequences and difference sequences respectively, which are then combined into a three-dimensional cross-difference matrix according to a unified time index. This allows the generated load difference signal to have multi-dimensional constraints and multi-feature expressions, with the aim of improving the relative accuracy and robustness of the results. In addition, during the iterative process, the data at the current time point in the three-dimensional cross-difference matrix is ​​first used as the initial value for iteration, and the charging state of the oil chamber accumulator and the opening state of the control valve group are read simultaneously. Then, the initial value for iteration is combined with the charging state and the opening state to obtain the corrected iterative result. Next, it is determined whether the iterative result falls within the preset reference range. If the result deviates from the reference range, the previous value of this iteration is returned to the initial difference set and re-entered for calculation until the iterative result converges. When the iterative result meets the convergence condition, the result is output as the final load difference signal, and an energy storage control command is generated based on the load difference signal. The energy storage control command is used to set the upper limit of the charging process, the upper limit of the releasing process, and the upper limit of the energy change rate.

[0019] The execution of the energy management module includes: Receive the energy storage control command generated by the difference calculation module and invoke the oil cavity accumulator; When the load decreases and falls below a preset threshold, the system controls the oil chamber accumulator to perform a charging action according to the energy storage control command, storing the pressure energy in the hydraulic circuit in the oil chamber accumulator. When the load decreases and falls below the preset threshold, it means that the real-time load parameters collected by the load sensor and pressure sensor and transmitted to the controller are continuously monitored. When the real-time load parameters show a continuous downward trend relative to the value at the previous time point, and the value after the decrease is lower than the lower limit of the preset threshold range, the system determines that the condition of load decrease and falling below the preset threshold is met, thereby triggering the energy management module to perform a charging action on the oil chamber accumulator. In addition, the charging action refers to the process by which high-pressure oil in the hydraulic circuit is guided into the oil chamber accumulator under the regulation of the control valve group, so that the compression medium inside the oil chamber is further compressed and energy is accumulated. Storing the pressure energy in the hydraulic circuit into the oil chamber accumulator means that by having oil enter the oil chamber accumulator, the pressure energy generated in the hydraulic circuit is converted into the elastic energy of the compression medium inside the accumulator, thereby achieving energy preservation. During the charging action, the speed change rate of the hydraulic drive actuator is monitored and compared with a preset threshold range. When the speed change rate tends to exceed the preset threshold range, the charging rate of the oil chamber accumulator is adjusted to keep the speed change rate within the preset threshold range. During the energy charging process, the real-time rotational speed of the hydraulically driven actuator is collected, and the rate of change of speed is calculated based on the speed difference between adjacent moments. Then, the rate of change of speed is compared one by one with the upper and lower limits of a preset threshold range. When the comparison results show that the rate of change of speed is gradually approaching or exceeding the boundary of the threshold range, the controller adjusts the charging rate of the accumulator in the oil chamber according to the energy storage control command. By changing the opening of the control valve group, the flow rate of oil entering the oil chamber is reduced or increased, so that the rate of change of speed is maintained within the preset threshold range again.

[0020] The execution of the adaptive release module includes: Under a unified preset time index, the time series of the load difference signal and the virtual load curve are retrieved. The load difference value at the same time point is subtracted from the virtual load value to form a time series difference set. At each time point, adjacent difference values ​​are subtracted to calculate the local rate of change. Then, each local rate of change is interpolated in time order to form a continuous change curve to generate a predicted release curve. In this execution step, the time series difference set is used to characterize the direct deviation between the load difference signal and the virtual load curve at each time point; the local rate of change is used to characterize the rate of change of the deviation between adjacent time points, thereby revealing the speed of the difference change; the continuous change curve formed by interpolation is used to transition the discrete local rate of change into a smooth time function to avoid control instability caused by abrupt changes. The final predicted release curve can provide a continuous and adjustable reference trajectory for subsequent energy release. Based on the predicted release curve values ​​at each time point, an energy release command is generated, and the oil chamber accumulator is invoked. The oil chamber accumulator is controlled to release oil at a corresponding flow rate when the predicted release curve value is higher than zero, and to remain closed when the predicted release curve value is lower than zero, thereby achieving segmented energy injection. Generating the energy release command based on the predicted release curve values ​​at each time point means reading the value at the corresponding time point on the predicted release curve and converting this value into a target release rate parameter for the oil chamber accumulator, thus forming a command to drive the control valve group to perform energy release. During the execution of the energy release command, the angular velocity of the hydraulically driven actuator is continuously acquired, and the difference in angular velocity between adjacent moments is calculated to obtain the rate of change of angular velocity. The rate of change of angular velocity is compared with a preset threshold range. When the comparison result shows that the rate of change of angular velocity exceeds the threshold range, the release rate of the oil chamber accumulator is adjusted. The flow rate is redefined by changing the opening of the control valve group, so that the angular velocity of the hydraulically driven actuator is kept within the preset threshold range. Specifically, during the execution of the energy release command, the angular velocity of the hydraulically driven actuator is first continuously acquired, and the difference between adjacent moments is calculated to obtain the rate of change of angular velocity. Then, the rate of change of angular velocity is compared with the upper and lower limits of the preset threshold range. When the comparison result shows that the rate of change of angular velocity exceeds the threshold range, the controller adjusts the release rate of the oil chamber accumulator according to the energy storage control command, and redefined the oil flow rate by changing the opening of the control valve group, so that the angular velocity of the hydraulically driven actuator is kept within the preset threshold range again.

[0021] The working principle of this scheme is as follows: In the hydraulic drive module, the load sensor, pressure sensor and drive wheel hydraulic motor output crop resistance, hydraulic pressure and speed respectively, and the controller forms real-time load parameters based on these; the virtual load module normalizes the real-time load parameters and establishes the parameter correspondence, solves the crop resistance fluctuation rate and speed-pressure coupling factor, generates a virtual load curve, and constructs a constant resistance reference benchmark by combining the charging state of the oil chamber accumulator and the opening state of the control valve group. The difference calculation module first compares the values ​​point by point under a unified preset time index to obtain an initial set of differences, and then performs three layers of screening in sequence (crop resistance fluctuation amplitude, hydraulic pressure change rate, and phase difference between rotation speed and pressure). Differences that do not meet the conditions are backtracked to the previous time window to form corrected differences. Then, the ratio of the speed change rate to the pressure change rate is calculated to obtain the coupling ratio. The correction difference and the coupling ratio are then subjected to three types of operations: product, ratio, and difference, which are combined into a three-dimensional cross difference matrix. The correction is then iteratively corrected according to the accumulator charging state and the valve group opening state until the final load difference signal is output. The controller generates energy storage control commands based on the final load difference signal, specifying the upper limit of the charging process, the upper limit of the releasing process, and the upper limit of the energy change rate. When the energy management module detects that the load has dropped and is below the threshold, it calls the oil chamber accumulator to perform the charging action, monitors the speed change rate of the hydraulic drive actuator and compares it with the threshold range, and adjusts the charging rate as necessary to constrain the speed change rate. The adaptive release module generates a predicted release curve based on the load difference signal time series and the virtual load curve, maps its value into an energy release command, and calls the oil chamber accumulator to inject energy into the hydraulic servo. During the execution process, it monitors the deviation of the angular velocity from the threshold range and adjusts the release rate, ultimately realizing closed-loop control of energy absorption and energy release and stable control of angular velocity, suppressing speed-torque reversal and pressure shock caused by sudden load changes, and maintaining continuous operation of the whole machine.

[0022] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A hydraulic drive device for a corn harvester, comprising a hydraulic drive module, a virtual load module, a differential calculation module, and an energy management module, characterized in that: The hydraulic drive module includes a drive wheel hydraulic motor, a load sensor, a pressure sensor, an oil chamber accumulator, and a control valve group. The drive wheel hydraulic motor is installed near the drive wheel and connected to the hydraulic circuit. The load sensor and pressure sensor are connected to the controller via a data acquisition path and output real-time load parameters. The oil chamber accumulator is connected in parallel between the inlet and return branches of the drive wheel hydraulic motor through the control valve group and performs energy absorption and release in response to control commands. The control valve group includes a one-way shut-off valve and a proportional control valve. The virtual load module is used to call the real-time load parameters, generate a virtual load curve, and construct a constant resistance reference benchmark; The difference calculation module is used to perform difference calculation between the real-time load parameters and the virtual load curve, solve the load difference signal and generate energy storage control instructions. The energy storage control instructions are used to control the upper limit of the charging process, the upper limit of the releasing process and the upper limit of the energy change rate. The energy management module is used to call the oil chamber accumulator and perform a charging action when the load decreases according to the energy storage control command, so as to limit the speed change rate of the hydraulic drive actuator within a preset threshold range.

2. The hydraulic drive device for a corn harvester according to claim 1, characterized in that: It also includes an adaptive release module; the adaptive release module generates a predicted release curve based on the time series of the load difference signal and the virtual load curve, calls the oil chamber accumulator to output an energy release command according to the predicted release curve and injects energy into the hydraulic servo, and controls the angular velocity of the hydraulic drive actuator to be within a preset threshold range.

3. The hydraulic drive device for a corn harvester according to claim 2, characterized in that: The execution of the virtual load balancer module includes: The load sensor in the hydraulic drive module is called to generate crop resistance data, the pressure sensor is called to generate hydraulic pressure data, and the rotational speed data output by the hydraulic motor of the drive wheel is called to generate real-time load parameters. The real-time load parameters are normalized to form crop resistance sequence, hydraulic pressure sequence and rotation speed sequence, and the parameter correspondence is established. In the parameter correspondence, the hydraulic pressure sequence is matched one-to-one with the speed sequence according to the time index, the speed change rate and pressure change rate per unit time are calculated, and the ratio of the speed change rate to the pressure change rate is used as the speed-pressure coupling factor. The volatility of the crop resistance sequence is weighted and superimposed with the velocity-pressure coupling factor to generate a virtual load curve, which corresponds to the theoretical reference curve under constant resistance conditions. The current state data of the oil chamber accumulator and the control valve group are called up, and the virtual load curve is combined with the charging state of the oil chamber accumulator and the opening state of the control valve group to construct a constant resistance reference benchmark.

4. The hydraulic drive device for a corn harvester according to claim 3, characterized in that: The execution of the difference calculation module includes: The real-time load parameters and the virtual load curve are compared point by point under a unified preset time index to generate an initial set of differences. The initial difference set is subjected to three layers of screening in sequence. The first layer of screening is based on whether the fluctuation amplitude of crop resistance data exceeds the upper and lower limits of a preset threshold. The second layer of screening is based on whether the rate of change of hydraulic pressure data is within the allowable range. The third layer of screening is based on whether the phase difference between rotation speed data and hydraulic pressure data is maintained within a preset synchronization range. When any layer of screening result does not meet the conditions, the corresponding difference is returned and the data of the previous time window of the virtual load curve is called again to form a corrected difference. The corrected difference is cross-mapped with the coupling ratio of the speed data and hydraulic pressure data. The coupling ratio represents the ratio of the rate of change of speed to the rate of change of hydraulic pressure calculated under a unified time index. The cross-mapping includes performing three types of operations simultaneously at each time point: the first type of operation includes multiplying the corrected difference with the coupling ratio to generate a product sequence; the second type of operation includes dividing the corrected difference by the coupling ratio to generate a ratio sequence; and the third type of operation includes subtracting the corrected difference from the coupling ratio to generate a difference sequence. The product sequence, ratio sequence, and difference sequence are combined according to the time index to form a three-dimensional cross-difference matrix.

5. The hydraulic drive device for a corn harvester according to claim 4, characterized in that: The execution of the difference calculation module also includes: The three-dimensional cross difference matrix is ​​iterated repeatedly. Each iteration is corrected by combining the charging state of the oil chamber accumulator with the opening state of the control valve group. When the iteration result deviates from the preset reference range, the previous iteration value is returned to the initial difference set and re-entered for calculation until the final load difference signal that meets the convergence condition is generated. Based on the final load difference signal, an energy storage control command is output. The energy storage control command is used to control the upper limit of the charging process, the upper limit of the releasing process, and the upper limit of the energy change rate.

6. The hydraulic drive device for a corn harvester according to claim 5, characterized in that: The execution of the energy management module includes: Receive the energy storage control command generated by the difference calculation module and invoke the oil cavity accumulator; When the load decreases and falls below a preset threshold, the oil chamber accumulator is controlled to perform a charging action according to the energy storage control command, storing the pressure energy in the hydraulic circuit in the oil chamber accumulator. During the charging process, the speed change rate of the hydraulic drive actuator is monitored and compared with a preset threshold range. When the speed change rate tends to exceed the preset threshold range, the charging rate of the oil chamber accumulator is adjusted to keep the speed change rate within the preset threshold range.

7. A hydraulic drive device for a corn harvester according to claim 2 or 6, characterized in that: The execution of the adaptive release module includes: Under a unified preset time index, the time series of the load difference signal and the virtual load curve are called. The load difference value and the virtual load value at the same time point are subtracted to form a time series difference set. At each time point, the adjacent difference values ​​are subtracted to calculate the local change rate. Then, each local change rate is interpolated in time order to form a continuous change curve to generate a predicted release curve. Based on the value of the predicted release curve at each time point, an energy release command is generated, and the oil chamber accumulator is invoked. The oil chamber accumulator is controlled to release oil at a corresponding flow rate when the value of the predicted release curve is higher than zero, and to remain closed when the value of the predicted release curve is lower than zero, so as to realize the segmented injection of energy. During the execution of the energy release command, the angular velocity of the hydraulically driven actuator is continuously collected, and the difference in angular velocity between adjacent moments is calculated to obtain the rate of change of angular velocity. The rate of change of angular velocity is compared with a preset threshold range. When the comparison result shows that the rate of change of angular velocity exceeds the threshold range, the release rate of the oil chamber accumulator is adjusted, and the flow rate is redefined by changing the opening of the control valve group, so that the angular velocity of the hydraulically driven actuator is kept within the preset threshold range.

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