Hydraulic drive for a corn harvester

Abstract

The application discloses a kind of hydraulic drive devices of corn harvester, specifically relates to the field of vehicle transmission system based on hydraulic drive and adaptive control, including hydraulic drive module, virtual load module, difference calculation module and energy management module;Hydraulic drive module includes drive wheel hydraulic motor, load sensor, pressure sensor, oil cavity accumulator and control valve group;The drive wheel hydraulic motor is installed in the position close to drive wheel and is connected with hydraulic circuit;The load sensor and pressure sensor are connected to the controller by acquisition channel and output real-time load parameter.Combining difference calculation module by constructing virtual load curve and generating energy storage control instruction, then the energy storage and release process of oil cavity accumulator is constrained and adjusted by energy management and adaptive release module, to inhibit the speed instability and torque reversal of hydraulic drive execution component when load suddenly drops.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of vehicle transmission system based on hydraulic drive and adaptive control, more particularly, the present application relates 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;

[0003] 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 drop in pressure triggers the excessive torque release of the hydraulic servo, causing the speed of the execution component to rise nonlinearly in a very short time;

[0004] This "speed and torque reversal" not only directly destroys the uniform cutting effect of crops, but also causes strong impact in the return oil pipeline, resulting in pump cavitation and system fatigue damage; therefore, 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

[0005] 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.

[0006] 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;

[0007] 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 close to the drive wheel and connected with the hydraulic circuit; the load sensor and the pressure sensor are connected to the controller through the 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;

[0008] The virtual load module is used to call the real-time load parameters, generate a virtual load curve and build a constant resistance reference benchmark;

[0009] The difference calculation module is used to perform difference operation on the real-time load parameters and the virtual load curve, solve the load difference signal and generate an energy storage control instruction, which is used to control the upper limit of the charging process, the upper limit of the release process and the upper limit of the energy change rate;

[0010] The energy management module is used to call the oil cavity accumulator and perform charging action when the load drops according to the energy storage control instruction, so as to limit the speed change rate of the hydraulic drive execution component within a preset threshold range.

[0011] In a preferred embodiment, an adaptive release module is further included; the adaptive release module generates a predicted release curve based on the time sequence of the load difference signal and the virtual load curve, calls the oil cavity accumulator to output an energy release instruction according to the predicted release curve and injects energy to the hydraulic servo, so as to control the angular velocity of the hydraulic drive execution component within a preset threshold range.

[0012] In a preferred embodiment, the execution of the virtual load module comprises:

[0013] The load sensor in the hydraulic drive module is called to form crop resistance data, the pressure sensor is called to form hydraulic pressure data, and the rotational speed data output by the drive wheel hydraulic motor is called to generate real-time load parameters;

[0014] The real-time load parameters are normalized to form a crop resistance sequence, a hydraulic pressure sequence and a rotational speed sequence, and a parameter correspondence relationship is established;

[0015] In the parameter correspondence relationship, the hydraulic pressure sequence is one-to-one corresponding to the rotational speed sequence according to the time index, the rotational speed change rate and the pressure change rate within a unit time are calculated, and the ratio of the rotational speed change rate to the pressure change rate is taken as a speed-pressure coupling factor;

[0016] The crop resistance sequence is subjected to a weighted superposition operation with the speed-pressure coupling factor to generate a virtual load curve corresponding to a theoretical reference curve under a constant resistance working condition;

[0017] The current state data of the oil chamber accumulator and the control valve group are called to combine the virtual load curve 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.

[0018] In a preferred embodiment, the execution of the difference calculation module comprises:

[0019] The real-time load parameters are compared with the virtual load curve point by point under a unified preset time index to generate an initial difference set;

[0020] The initial difference set is sequentially subjected to three layers of screening, the first layer of screening is based on whether the fluctuation amplitude of the crop resistance data exceeds the upper and lower limits of a preset threshold, the second layer of screening is based on whether the change rate of the hydraulic pressure data is within an allowed range, and the third layer of screening is based on whether the phase difference between the rotational speed data and the hydraulic pressure data remains within a preset synchronization range, when the result of any layer of screening does not meet the condition, the corresponding difference value is returned and the last time window data of the virtual load curve is called again to form a revised difference value;

[0021] The revised difference value is cross-mapped with a coupling ratio of the rotational speed data and the hydraulic pressure data, the coupling ratio represents the ratio of the change rate of the rotational speed to the change rate of the hydraulic pressure under a unified time index; the cross-mapping includes three types of operations simultaneously performed at each time point: one type of operation includes multiplying the revised difference value by the coupling ratio to generate a product sequence; the second type of operation includes dividing the revised difference value by the coupling ratio to generate a ratio sequence; the third type of operation includes subtracting the revised difference value from the coupling ratio to generate a difference sequence; the product sequence, the ratio sequence and the difference sequence are combined according to the time index to form a three-dimensional cross-difference matrix.

[0022] In a preferred embodiment, the execution of the difference calculation module further comprises:

[0023] The three-dimensional cross-difference matrix is subjected to a loop iteration, and the charging state of the oil chamber accumulator and the opening state of the control valve group are combined for correction at each iteration, when the iteration result deviates from a preset reference range, the previous iteration value is returned to the initial difference set and the calculation is re-entered until a final load difference signal meeting a convergence condition is generated;

[0024] Based on the final load difference signal, an energy storage control instruction is output, the energy storage control instruction is used to control the upper limit of the charging process, the upper limit of the release process and the upper limit of the energy change rate.

[0025] In a preferred embodiment, the execution of the energy management module comprises:

[0026] receiving the energy storage control instruction generated by the difference calculation module, and calling the oil chamber accumulator;

[0027] when the load drop is identified and is lower than the preset threshold, controlling the oil chamber accumulator to perform the energy storage action according to the energy storage control instruction, so as to store the pressure energy in the hydraulic circuit in the oil chamber accumulator;

[0028] during the execution of the energy storage action, monitoring the speed change rate of the hydraulic drive execution component, and comparing the speed change rate with a preset threshold range, when the speed change rate tends to exceed the preset threshold range, adjusting the energy storage rate of the oil chamber accumulator, so as to keep the speed change rate within the preset threshold range.

[0029] In a preferred embodiment, the execution of the adaptive release module comprises:

[0030] at a unified preset time index, calling the time sequence of the load difference signal and the virtual load curve, subtracting the load difference value at the same time point from the virtual load value to form a time sequence difference set, subtracting adjacent difference values at each time point to calculate a local change rate, and interpolating the local change rates in time sequence to form a continuous change curve, so as to generate a predicted release curve;

[0031] generating an energy release instruction according to the value of the predicted release curve at each time point, and calling the oil chamber accumulator, controlling the oil chamber accumulator to release oil at a corresponding flow rate when the value of the predicted release curve is higher than zero, and keeping the oil chamber accumulator in a closed state when the value of the predicted release curve is lower than zero, so as to realize segmented injection of energy;

[0032] during the execution of the energy release instruction, continuously collecting the angular velocity of the hydraulic drive execution component, and calculating the angular velocity difference between adjacent time points to obtain an angular velocity change rate, comparing the angular velocity change rate with a preset threshold range, and when the comparison result shows that the angular velocity change rate exceeds the threshold range, adjusting the release rate of the oil chamber accumulator, and redefining the flow rate by changing the opening degree of the control valve group, so as to keep the angular velocity of the hydraulic drive execution component within the preset threshold range.

[0033] Technical effects and advantages of the present application:

[0034] The scheme triggers the oil chamber accumulator to perform energy storage and rate constraint when the load is identified to be reduced, instead of directly reducing the output, so as to avoid the speed and torque reversal of the hydraulic drive execution component caused by the sudden drop of pressure, thereby inhibiting the speed instability and oil return impact problem of the execution component;

[0035] The virtual load module of the scheme constructs a virtual load curve and forms a constant resistance reference benchmark through the serialization processing of crop resistance, hydraulic pressure and rotation speed, realizes the dynamic mapping of real load fluctuation, and enables the driving process to have a steady state constraint ability independent of single pressure feedback;

[0036] The difference calculation module of the scheme performs step-by-step correction and convergence operation on the difference value through three-layer screening and three-dimensional cross-difference matrix cyclic iteration mechanism, so as to ensure that the final load difference signal has multi-dimensional constraint characteristics, thereby making the generation of energy storage control instruction have stability and robustness;

[0037] The energy management module of the scheme monitors the speed change rate of the hydraulic drive execution component in real time when performing the energy storage action, and maintains the speed change rate within the preset threshold range by dynamically adjusting the energy storage rate of the accumulator, thereby reducing the speed fluctuation risk caused by operation mutation;

[0038] The adaptive release module of the scheme generates a predicted release curve based on the load difference signal and the virtual load curve, and adjusts the energy release process of the accumulator according to the predicted release curve, while monitoring and adjusting the angular velocity of the execution component, so as to ensure that the energy release process and the operation load are dynamically highly matched, and realize stable and continuous driving output. BRIEF DESCRIPTION OF DRAWINGS

[0039] Figure 1 The figure is a schematic diagram of the system module of the device. DETAILED DESCRIPTION

[0040] The technical solutions in the embodiments of the present application will be described clearly and completely below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor fall within the scope of protection of the present application.

[0041] With reference to the drawings in the description Figure 1 An embodiment of the present application is a hydraulic drive device of a corn harvester, which comprises a hydraulic drive module, a virtual load module, a difference calculation module and an energy management module.

[0042] 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 close to the drive wheel and connected with the hydraulic circuit; the load sensor and the pressure sensor are connected to the controller through the 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;

[0043] The virtual load module is used to call the real-time load parameters, generate a virtual load curve and build a constant resistance reference benchmark;

[0044] The difference calculation module is used to perform difference operation on the real-time load parameters and the virtual load curve, solve the load difference signal and generate an energy storage control instruction, which is used to control the upper limit of the charging process, the upper limit of the release process and the upper limit of the energy change rate;

[0045] The energy management module is used to call the oil cavity accumulator and perform the charging action when the load drops according to the energy storage control instruction, so as to limit the speed change rate of the hydraulic drive execution component within a preset threshold range;

[0046] It should be noted that the execution process of the hydraulic drive module is as follows: the drive wheel hydraulic motor is fixed close to the drive wheel and connected to the hydraulic circuit through the oil inlet branch and the oil return branch to generate the rotary torque of the drive wheel under the action of the control instruction; when the crops enter the header, the load sensor collects the resistance value of the crops acting on the working component in real time, and the pressure sensor detects the hydraulic pressure value in the oil inlet branch and the oil return branch at the same time; the above-mentioned values are transmitted to the controller through the collection channel and form the real-time load parameters; the controller generates the corresponding control instruction after receiving the real-time load parameters and transmits the control instruction to the control valve group; the control valve group is composed of a one-way stop valve and a proportional control valve, the one-way stop valve ensures the flow of hydraulic oil in a predetermined direction, and the proportional control valve adjusts the valve opening degree according to the control instruction to change the oil flow; under the action of the control valve group, the oil cavity accumulator is connected in parallel with the oil inlet branch and the oil return branch, when the real-time pressure is higher than the threshold value, the proportional control valve opening degree is reduced to guide the oil into the oil cavity accumulator and perform the charging action, when the real-time pressure is lower than the threshold value, the proportional control valve opening degree is increased to guide the oil cavity accumulator to release the stored energy and inject the oil back into the circuit, so as to realize the dynamic control of energy absorption and energy release in the whole process and ensure the stable operation of the drive wheel hydraulic motor under different working conditions;

[0047] In addition, the energy absorption refers to that when the hydraulic circuit pressure is higher than the threshold value, the oil is introduced into the oil chamber accumulator and the internal medium is compressed, so as to store the excess hydraulic energy in the oil chamber; the energy release refers to that when the hydraulic circuit pressure is lower than the threshold value, the rebound of the internal medium of the oil chamber accumulator pushes the oil to flow back to the hydraulic circuit, so as to re-inject the previously stored energy into the driving wheel hydraulic motor and the related execution components; the two form a closed cycle, which is used to balance the pressure fluctuation of the hydraulic system and maintain the continuity of the driving process.

[0048] Further comprising an adaptive release module; the adaptive release module generates a predicted release curve based on the time sequence of the load difference signal and the virtual load curve, calls the oil chamber accumulator to output energy release instructions according to the predicted release curve and injects energy into the hydraulic servo, and controls the angular velocity of the hydraulic driving execution component to be within a preset threshold range.

[0049] The execution of the virtual load module includes:

[0050] The load sensor in the hydraulic driving module is called to form crop resistance data, the pressure sensor is called to form hydraulic pressure data, and the rotational speed data output by the driving wheel hydraulic motor is called to form real-time load parameters; wherein the crop resistance data is the resistance value of the crop acting on the working component at the header or the feeding inlet collected by the load sensor, reflecting the mechanical load generated when the crop enters; the hydraulic pressure data is the pressure value of the hydraulic circuit in the oil inlet branch and the oil return branch of the driving wheel hydraulic motor collected by the pressure sensor, reflecting the fluid pressure state of the hydraulic system under real-time working conditions; the rotational speed data is the angular velocity value output by the driving wheel hydraulic motor, reflecting the rotational speed of the hydraulic driving execution component per unit time;

[0051] The real-time load parameters are normalized to form a crop resistance sequence, a hydraulic pressure sequence and a rotational speed sequence, and a parameter correspondence is established; wherein the normalization refers to mapping different dimension values of the real-time load parameters to a unified value interval through the same conversion rule, so that the crop resistance data, the hydraulic pressure data and the rotational speed data have comparability and consistency in the calculation process, including linear proportional scaling of the original values or dimensionless conversion based on a preset threshold range; in addition, the establishment of the parameter correspondence refers to corresponding matching of the normalized crop resistance sequence, the hydraulic pressure sequence and the rotational speed sequence one by one according to a unified time index, so that the three sequence values at the same time point form a set of associated parameters for subsequent calculation and analysis;

[0052] In the parameter correspondence, the hydraulic pressure sequence is one-to-one corresponding to the rotational speed sequence according to the time index, the rotational speed change rate and the pressure change rate per unit time are calculated, and the ratio of the rotational speed change rate to the pressure change rate is taken as the speed-pressure coupling factor;

[0053] The fluctuation rate of the crop resistance sequence is weighted and superimposed with the speed-pressure coupling factor to generate a virtual load curve corresponding to a theoretical reference curve under a constant resistance working condition; it should be noted that during the weighted superimposed operation, first, the numerical fluctuation amplitude of the crop resistance sequence in a unit time window is calculated to form a crop resistance fluctuation rate; then the ratio of the rotational speed sequence change rate to the hydraulic pressure sequence change rate is calculated to form a speed-pressure coupling factor; then the crop resistance fluctuation rate and the speed-pressure coupling factor are multiplied according to a preset weight ratio and summed to obtain a virtual load value at each time point; finally, the virtual load values are arranged in time sequence to generate a virtual load curve, which serves as a theoretical reference curve under a constant resistance working condition;

[0054] The current state data of the oil chamber accumulator and the control valve group are called to combine the virtual load curve 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; during the construction of the constant resistance reference benchmark, the charging state data of the oil chamber accumulator and the opening state data of the control valve group are first called and matched with the virtual load curve at the same time index; then, according to the value of the virtual load curve, it is determined whether the charging amount of the oil chamber accumulator and the opening size of the control valve group need to be adjusted to form a linkage relationship between the virtual load and the hardware state; finally, the adjusted charging state, opening state and virtual load curve are superimposed to generate a constant resistance reference benchmark for constraining the operation of the hydraulic drive execution component; wherein the current state data of the oil chamber accumulator refers to its pressure value and charging amount data under real-time working conditions; the current state data of the control valve group refers to the opening position and flow passage state of the one-way stop valve and the proportional control valve under real-time working conditions.

[0055] The execution of the difference calculation module includes:

[0056] 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 difference set; during the point-by-point comparison, first, the crop resistance data, hydraulic pressure data and rotational speed data can be arranged in time sequence to form a time sequence; then the virtual load curve is called to arrange the virtual load values in 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, and all single-point differences are combined in time sequence to finally form an initial difference set;

[0057] The initial difference set is sequentially subjected to three layers of screening, the first layer of screening is based on whether the fluctuation amplitude of the crop resistance data exceeds the upper and lower limits of a preset threshold, the second layer of screening is based on whether the change rate of the hydraulic pressure data is within an allowed interval, and the third layer of screening is based on whether the phase difference between the rotation speed data and the hydraulic pressure data remains within a preset synchronization interval, when the result of any layer of screening does not satisfy the condition, the corresponding difference value is returned and the last time window data of the virtual load curve is re-called to form a corrected difference value;

[0058] The corrected difference value is cross-mapped with a coupling ratio of the rotation speed data and the hydraulic pressure data, the coupling ratio represents the ratio of the rotation speed change rate to the hydraulic pressure change rate calculated under a unified time index, specifically, the differential value of the rotation speed at adjacent time points is calculated at each time point and divided by the differential value of the hydraulic pressure at adjacent time points to form the coupling ratio at the time point; the cross-mapping includes simultaneously performing three types of operations at each time point: one type of operation includes multiplying the corrected difference value by the coupling ratio to generate a product sequence; the second type of operation includes dividing the corrected difference value by the coupling ratio to generate a ratio sequence; the third type of operation includes subtracting the corrected difference value from the coupling ratio to generate a difference sequence; the product sequence, the ratio sequence and the difference sequence are combined according to the time index to form a three-dimensional cross-difference matrix.

[0059] The execution of the difference calculation module further includes:

[0060] The three-dimensional cross-difference matrix is subjected to a loop iteration, each iteration is combined with the charging state of the oil cavity accumulator and the opening state of the control valve group for correction, when the iteration result deviates from a preset reference interval, the previous iteration value is returned to the initial difference set and re-entered into the calculation until a final load difference signal satisfying a convergence condition is generated;

[0061] Based on the final load difference signal, an energy storage control instruction is output, the energy storage control instruction is used to control the upper limit of the charging process, the upper limit of the release process and the upper limit of the energy change rate;

[0062] It should be noted that the execution of the three layers of screening is to ensure the effectiveness and stability of the difference value before generating the load difference signal: the first layer is based on the fluctuation amplitude of the crop resistance data to confirm that the resistance change is within a reasonable range; the second layer is based on the change rate of the hydraulic pressure data to confirm that the dynamic response of the system pressure does not exceed the allowed interval; the third layer is based on the phase difference between the rotation speed data and the hydraulic pressure data to confirm that the speed and pressure of the executing component remain synchronized;

[0063] If any layer of screening fails, the difference value is returned and the previous time window data of the virtual load curve is called again to form a revised difference value, so as to avoid that the abnormal value directly enters the subsequent operation; on this basis, the ratio of the change rate of the speed to the change rate of the hydraulic pressure is introduced as a coupling ratio, which reflects the dynamic coupling relationship between the speed and the pressure;

[0064] The cross mapping of the revised difference value and the coupling ratio includes three types of operations: multiplication to obtain an enhanced effect, calculation of a quotient to obtain a relative strength, and difference to obtain a deviation degree; the three types of operations respectively output a product sequence, a ratio sequence and a difference sequence, and then the three sequences are combined according to a unified time index to form a three-dimensional cross difference matrix, so that the generated load difference signal has multi-dimensional constraints and multi-feature expressions, and the purpose is to improve the relative accuracy and robustness of the result;

[0065] In addition, in the process of loop iteration, first, the data of the current time point in the three-dimensional cross difference matrix is called as the initial value of iteration, and the charging state of the oil chamber accumulator and the opening state of the control valve group are read at the same time; then the initial value of iteration is combined with the charging state and the opening state to obtain a corrected iteration result; then it is judged whether the iteration result falls within a preset reference interval, if the result deviates from the reference interval, the previous value of this iteration is returned to the initial difference value set and re-entered into the calculation until the iteration result converges; when the iteration result meets the convergence condition, the result is output as the final load difference signal, and an energy storage control instruction is generated based on the load difference signal, the energy storage control instruction is used to set the upper limit of the charging process, the upper limit of the release process and the upper limit of the energy change rate.

[0066] The execution of the energy management module includes:

[0067] Receiving the energy storage control instruction generated by the difference calculation module, and calling the oil chamber accumulator;

[0068] When the load drop and the load drop below the preset threshold are identified, the oil chamber accumulator is controlled to perform the charging action according to the energy storage control instruction, and the pressure energy in the hydraulic circuit is stored in the oil chamber accumulator; wherein when the load drop and the load drop below the preset threshold are identified, it means that the real-time load parameters collected by the load sensor and the pressure sensor and transmitted to the controller are continuously monitored, when the real-time load parameters have a continuous downward trend compared with the values at the previous time point, and the value after the drop is lower than the lower limit of the preset threshold range, the system determines that the condition of load drop and load drop below the preset threshold is met, thereby triggering the energy management module to perform the charging action on the oil chamber accumulator;

[0069] In addition, the charging action refers to the process of guiding the high-pressure oil in the hydraulic circuit into the oil chamber accumulator under the regulation of the control valve group, so that the compressed medium inside the oil chamber is further compressed and accumulates energy;

[0070] The storage of pressure energy in the hydraulic circuit into the oil chamber accumulator refers to the conversion of pressure energy generated in the hydraulic circuit into the elastic energy of the compressed medium inside the accumulator by the oil entering the oil chamber accumulator, so as to realize the storage of energy;

[0071] During the execution of the charging action, the rate of change of the speed of the hydraulic drive execution component is monitored, and the rate of change of the speed is compared with a preset threshold range, and when the rate of change of the speed tends to exceed the preset threshold range, the charging rate of the oil chamber accumulator is adjusted to keep the rate of change of the speed within the preset threshold range;

[0072] During the execution of the charging action, the real-time rotational speed of the hydraulic drive execution component is collected, and the rate of change of the speed is calculated according to the difference between adjacent time points; then the rate of change of the speed is compared with the upper and lower limits of the preset threshold range one by one, and when the comparison result shows that the rate of change of the speed gradually approaches or exceeds the boundary of the threshold range, the controller adjusts the charging rate of the oil chamber accumulator according to the storage control instruction, reduces or increases the oil flow into the oil chamber by changing the opening of the control valve group, so that the rate of change of the speed is kept within the preset threshold range.

[0073] The execution of the adaptive release module includes:

[0074] The time sequence of the load difference signal and the virtual load curve are called at a unified preset time index, the load difference value at the same time point is subtracted from the virtual load value to form a time sequence difference set, and the local change rate is calculated by subtracting adjacent difference values at each time point, and then the local change rates are interpolated in time sequence to form a continuous change curve to generate a predicted release curve; in this execution step, the time sequence difference set is used to represent the direct deviation between the load difference signal and the virtual load curve at each time point; the local change rate is used to represent the change speed of the deviation between adjacent time points, so as to reveal the speed of the difference change; the continuous change curve formed by interpolation is used to transition the discrete local change rate to a smooth time function, so as to avoid control instability caused by sudden change points, and the final predicted release curve can provide a continuous and adjustable reference trajectory for subsequent energy release;

[0075] The energy release instruction is generated according to the value of the predicted release curve at each time point, and the oil cavity accumulator is called to control the oil cavity accumulator 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 achieve segmented injection of energy; wherein the energy release instruction is generated according to the value of the predicted release curve at each time point, which means that the value at the corresponding time point on the predicted release curve is read, and the value is converted into a target release rate parameter of the oil cavity accumulator, thereby forming an instruction for driving the control valve group to execute energy release.

[0076] During the execution of the energy release instruction, the angular velocity of the hydraulic drive execution component is continuously collected, and the angular velocity difference between adjacent time points is calculated to obtain an angular velocity change rate, which is compared with a preset threshold range. When the comparison result shows that the angular velocity change rate exceeds the threshold range, the release rate of the oil cavity accumulator is adjusted, and the opening of the control valve group is changed to redefine the flow rate, so that the angular velocity of the hydraulic drive execution component is kept within the preset threshold range. During the execution of the energy release instruction, the angular velocity of the hydraulic drive execution component is first continuously collected, and the angular velocity difference between adjacent time points is calculated to obtain an angular velocity change rate. Then, the angular velocity change rate is compared with the upper and lower limits of the preset threshold range. When the comparison result shows that the angular velocity change rate exceeds the threshold range, the controller adjusts the release rate of the oil cavity accumulator according to the energy storage control instruction, and changes the opening of the control valve group to redefine the oil flow rate, so that the angular velocity of the hydraulic drive execution component is kept within the preset threshold range.

[0077] The working principle of the scheme is as follows: in the hydraulic drive module, the load sensor, the pressure sensor and the drive wheel hydraulic motor respectively output the crop resistance, the hydraulic pressure and the rotational speed, and the controller forms the real-time load parameter accordingly; the virtual load module normalizes the real-time load parameter to establish a parameter correspondence relationship, solves the crop resistance fluctuation rate and the speed-pressure coupling factor, generates a virtual load curve, and constructs a constant resistance reference benchmark in combination with the energy storage state of the oil cavity accumulator and the opening state of the control valve group;

[0078] The difference calculation module first compares the initial difference set point by point under a unified preset time index, and then sequentially performs three layers of screening (crop resistance fluctuation amplitude, hydraulic pressure change rate, rotational speed and pressure phase difference). The difference values that do not meet the conditions are traced back to the previous time window to form corrected difference values;

[0079] Then, the coupling ratio is calculated by calculating the ratio of the rotational speed change rate and the pressure change rate, and three types of operations, i.e., multiplication, ratio and difference, are performed on the corrected difference values and the coupling ratio to form a three-dimensional cross-difference matrix, which is iteratively corrected according to the energy storage state of the accumulator and the opening state of the valve group until the final load difference signal is output.

[0080] 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.

[0081] 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.

[0082] 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 balancing 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.

Images