A flow value compensation method for hydraulic motor flow detection

Abstract

The application discloses a flow value compensation method for hydraulic motor flow detection, and comprises the following steps: constructing a hydraulic motor circuit, determining an initial flow compensation coefficient sequence of an oil inlet working port and an oil outlet working port, and obtaining a three-dimensional space curved surface model of continuous changes of the flow compensation coefficient with oil pressure and oil temperature; a hydraulic motor to be detected has two working oil ports, an arbitrary working oil port is selected, a flow sensor is arranged for the selected working oil port, the flow compensation coefficient of the hydraulic motor to be detected is determined based on the three-dimensional space curved surface model, and the flow of the hydraulic motor to be detected is numerically compensated according to the flow compensation coefficient. The method can accurately estimate the high-pressure oil delivery flow value through the low-pressure oil return flow, simplifies the complexity of the system, saves the equipment cost, effectively reduces the probability of equipment failure, and improves the fault tolerance of the system.

Description

Technical Field

[0001] This invention relates to the field of hydraulic component testing, and more specifically to a flow rate compensation method for flow rate detection of hydraulic motors. Background Technology

[0002] A hydraulic motor is a device that converts hydraulic energy into mechanical energy and is widely used in the field of self-propelled equipment. It transforms the hydraulic energy supplied by a hydraulic pump into the mechanical energy of the output shaft. The displacement of a hydraulic motor is one of its most important performance indicators. Its value is determined at the initial design stage by its relevant structural dimensions. To verify the accuracy of the motor's displacement, it is often necessary to test it before leaving the factory or putting it into use. Theoretically, the displacement... Traffic Divide by speed Calculated, that is As can be seen, to accurately measure displacement, it is necessary to know the speed and flow rate of the hydraulic motor. Generally, the speed of a hydraulic motor can be accurately measured using a speed sensor, and the flow rate can be measured using a flow sensor.

[0003] The hydraulic motor has two working ports, A and B. When high-pressure fluid is introduced into port A, the output shaft of the hydraulic motor rotates in a certain direction. The high-pressure fluid flowing into port A performs work and becomes low-pressure fluid, which then flows out through port B. Conversely, if high-pressure fluid is introduced into port B, the output shaft of the hydraulic motor rotates in the opposite direction. The high-pressure fluid flowing into port B performs work and becomes low-pressure fluid, which then flows out through port A.

[0004] When testing the displacement of a hydraulic motor, it is necessary to measure the displacement in both clockwise and counterclockwise rotations. Therefore, a flow sensor is needed to detect the flow rate during each rotation. As described earlier, during operation, the fluid at one of the two working ports of the hydraulic motor is under high pressure, while the other is under low pressure. Hydraulic fluid has compressibility; the same mass flow rate will have different volumetric flow rates under different pressures. Therefore, the displacement test must be conducted at both ports A and B of the hydraulic motor to ensure consistency in the test benchmark for both rotation directions.

[0005] This leads to a situation where, when testing the displacement of a hydraulic motor, if only one flow sensor is installed at one working port, regardless of whether the sensor is installed at port A or port B of the hydraulic motor, the volumetric flow rate measured by the flow sensor will be either under high pressure or low pressure conditions in the two different rotation directions of the hydraulic motor. This results in inconsistent flow detection benchmarks when calculating the displacement in the two different rotation directions.

[0006] To eliminate this inconsistency in reference values, it is often necessary to install a flow sensor at each of the two working ports of the hydraulic motor. Regardless of which direction of rotation the displacement is being measured, the measurement data from the high-pressure end of the flow sensor is selected. However, high-precision, high-pressure resistant flow sensors are generally very expensive, which increases the cost of the testing equipment. Summary of the Invention

[0007] In view of this, the present invention provides a flow rate compensation method for hydraulic motor flow rate detection, which can solve the technical problem of inconsistency in flow rate measurement reference caused by the inconsistency of fluid pressure under the forward and reverse operation of hydraulic motor.

[0008] To solve the above-mentioned technical problems, the present invention is implemented as follows.

[0009] A flow rate compensation method for flow detection of a hydraulic motor, comprising: Step S1: Construct a hydraulic motor circuit. Set a first flow sensor and a second flow sensor at the oil inlet and oil outlet of the hydraulic motor circuit, respectively. Obtain oil pressure data and oil temperature data at the oil inlet and oil outlet. Determine the initial flow compensation coefficient sequence of the oil inlet and oil outlet. Fit the initial flow compensation coefficient sequence based on the two-dimensional cubic spline interpolation method to obtain a three-dimensional spatial surface model in which the flow compensation coefficient changes continuously with oil pressure and oil temperature. Step S2: Obtain the hydraulic motor whose flow rate is to be detected. The hydraulic motor whose flow rate is to be detected has two working ports. Select any one of the working ports and set a flow sensor for the selected working port. Determine the flow compensation coefficient of the hydraulic motor whose flow rate is to be detected based on the three-dimensional spatial surface model. Perform numerical compensation on the flow rate of the hydraulic motor whose flow rate is to be detected according to the flow compensation coefficient.

[0010] Preferably, step S1, acquiring hydraulic data and oil temperature data of the inlet and outlet, and determining the initial flow compensation coefficient sequence of the inlet and outlet, includes: Step S11: Obtain the maximum oil supply pressure Pmax of the hydraulic motor circuit, determine the number of segments m according to the specifications of the hydraulic motor, and obtain the segment step size. The first sequence is obtained. ; Step S12: For each element in the first sequence , All of them shall perform the following operations: The initial oil temperature T0 is taken as the oil temperature before the hydraulic motor circuit starts working, and the highest allowable oil temperature during operation is taken as the maximum oil temperature Tmax. The range [T0, Tmax] is divided into n temperature intervals to obtain the second sequence {Tnum}. That is, {T0, T0+} T0+2 ..., T0+n }, where T0+n =Tmax; For each temperature value in the second sequence, when the oil temperature in the hydraulic motor circuit reaches that temperature value, the flow rates at the inlet and outlet are obtained by the first and second flow sensors respectively, and recorded as follows: and Calculate the flow compensation between the two working ports. The calculation method is as follows: The initial flow compensation coefficient sequence is obtained. ={ },in , , , Each value in the initial flow compensation coefficient sequence represents a value corresponding to the oil supply pressure. With oil temperature The flow compensation coefficient, wherein each pressure value in the first sequence is also called a pressure node, and the first sequence with m pressure nodes can determine m-1 pressure intervals; each temperature value in the second sequence is also called a temperature node, and the second sequence with n+1 temperature nodes can determine n temperature intervals; Step S13: For the first sequence For each element in the list, perform the following operations: Under the given conditions, for each temperature value in the second sequence, the initial flow compensation coefficient sequence is fitted with a cubic function of the compensation coefficients with respect to the oil temperature using one-dimensional cubic spline interpolation, thus obtaining the first initial flow compensation sequence. , ; For the second sequence {Tnum}, i.e. {T0, T0+} T0+2 ..., T0+n Each element in} performs the following operation: Under the given conditions, for each pressure value in the first sequence, the initial flow compensation coefficient sequence is fitted with a cubic function of the compensation coefficient with respect to the oil supply pressure using one-dimensional cubic spline interpolation, thus obtaining the second initial flow compensation coefficient sequence. , .

[0011] Preferably, step S1, which involves fitting the initial flow compensation coefficient sequence based on a two-dimensional cubic spline interpolation method to obtain a three-dimensional spatial surface model in which the flow compensation coefficients continuously change with oil pressure and oil temperature, includes: Step S14: For each first initial flow compensation sequence , All of them shall perform the following operations: For the first initial flow compensation sequence For each of the corresponding n temperature ranges, a compensation coefficient is constructed based on the oil temperature. The cubic function is obtained. in, They represent unknown coefficients, It is the oil supply pressure Under the condition of the first A cubic function is constructed from several temperature intervals, where {T0, ..., Tn} is the second sequence, and T is the independent variable representing the oil temperature. ; The following constraints are constructed for solving: get cubic function under certain conditions , , The cubic function of the i1th temperature interval at oil temperature is The value of time, for Time The compensation coefficients calculated at each temperature node. The cubic function of the nth temperature range at oil temperature is The value at time; for The compensation coefficient calculated at the nth temperature node. The cubic function of the i2th temperature interval at oil temperature is The value of time, The cubic function of the i2+1th temperature interval at oil temperature is The value of time, , They are respectively , The first derivative, , They are respectively , The second derivative, and All are preset to 0; Step S15: The first sequence It is denoted as {P0,……,Pm-1}, that is, there are m pressure nodes, corresponding to m-1 pressure intervals; For each second initial flow compensation coefficient sequence , All of them shall perform the following operations: For the second initial flow compensation coefficient sequence For each of the corresponding m-1 pressure ranges, a compensation coefficient is constructed based on the oil supply pressure. The cubic function is obtained.

[0012] in, They represent unknown coefficients, Oil temperature Under the condition of the first A cubic function constructed over a temperature range. The independent variable is the oil supply pressure. ; The following constraints are constructed for solving:

[0013] get cubic function under certain conditions ,in, , The cubic function of the j1-th pressure interval at the oil supply pressure is The value of time, for Time The compensation coefficients calculated for each pressure node. The cubic function of the (m-1)th pressure interval at the oil supply pressure is The value of time, for The compensation coefficient calculated at the (m-1)th pressure node. The cubic function of the j2th pressure interval at the oil supply pressure is The value of time, The cubic function of the (j2+1)th temperature range at the oil supply pressure is The value of time, , They are respectively , The first derivative, , They are respectively , The second derivative, and All are preset to 0; Step S16: Based on the oil temperature Shaft, oil supply pressure is Shaft, compensation coefficient is Establish a spatial rectangular coordinate system based on the axes, and and By combining these parameters, a two-dimensional fitted surface model is obtained in which the compensation coefficient continuously varies with oil temperature and oil supply pressure.

[0014]

[0015] in, Indicates the first The temperature range and the first The compensation coefficient function within the rectangular region enclosed by several pressure intervals. Indicates the first The temperature node and the first Compensation coefficient at each pressure node. Indicates the first +1 temperature node and the first Compensation coefficient at each pressure node. Indicates the first The temperature node and the first +1 compensation coefficient at pressure nodes Indicates the first +1 temperature node and the first +1 compensation coefficient at pressure nodes; and ,in Indicates the first Temperature values ​​at each temperature node. Indicates the first Pressure values ​​at each pressure node, and ; Step S17: Based on the two-dimensional fitting surface model where the compensation coefficient continuously varies with oil temperature and oil supply pressure, obtain the three-dimensional spatial surface model where the compensation coefficient continuously varies with oil temperature and oil supply pressure. .

[0016] Preferably, step S2 includes: Step S21: Obtain the hydraulic motor with the flow rate to be detected. The hydraulic motor has two working ports. Select any one of the working ports and set a flow sensor for the selected working port. When the working port with the flow sensor is set as the oil inlet, no compensation is required, and the value measured by the flow sensor is output as the detection data, and the method ends. When the working port with the flow sensor is set as the oil outlet, the value measured by the flow sensor is recorded as... The real-time oil temperature T of the hydraulic motor with the flow rate to be detected is then measured by a temperature sensor, and the oil pressure P is measured by a pressure sensor at the oil inlet. Based on the three-dimensional spatial surface model, the current compensation coefficient of the hydraulic motor with the flow rate to be detected is determined. Proceed to step S22; Step S22: Obtain the leakage flow rate corresponding to the hydraulic motor whose flow rate is to be detected by the flow sensor for detecting leakage, and record it as... According to the current compensation coefficient Flow rate compensation is performed on the hydraulic motor whose flow rate is to be detected.

[0017] Preferably, based on the current compensation coefficient The hydraulic motor whose flow rate is to be detected is subjected to flow rate compensation, and the compensated flow rate value is: .

[0018] Preferably, the value of m is determined based on the power of the hydraulic motor.

[0019] The core idea of ​​the flow measurement compensation method proposed in this invention is based on the changes in the physical properties of hydraulic fluid under different operating conditions. It mainly considers the working pressure, oil temperature, and fluid medium of the hydraulic fluid. The volumetric flow rate of a specific fluid medium is measured beforehand, and its variation with fluid pressure and oil temperature at different oil temperatures is determined. Then, during actual hydraulic motor displacement testing, the flow rate measured under low pressure is compensated and converted to obtain the flow rate under high pressure.

[0020] Beneficial effects: (1) The present invention can accurately estimate the value of high pressure flow by low pressure flow, which simplifies the complexity of the system, saves equipment costs, effectively reduces the probability of equipment failure, and improves the fault tolerance of the system.

[0021] (2) The compensation relationship obtained by the present invention is adjusted in real time according to the changes in system temperature and pressure information, that is, the flow rate value can be accurately compensated at any time when the system is working.

[0022] (3) The three-dimensional compensation surface function calculated by this invention covers all temperature and pressure conditions of the hydraulic system, and is therefore applicable to all working stages of the hydraulic system. Moreover, this method is not limited by the working environment and has good applicability under various working conditions.

[0023] (4) The three-dimensional compensation surface model calculated by the present invention for a given hydraulic system is fixed. For a given system, the compensation conclusion will be applicable for a long time without considering external factors such as equipment replacement. Attached Figure Description

[0024] Figure 1 This is a flowchart illustrating the flow value compensation method for hydraulic motor flow detection provided by the present invention. Figure 2 This is a schematic diagram illustrating the principle of traffic data compensation in this invention. Figure 3 This is a schematic diagram for testing the displacement of a hydraulic motor, provided by the present invention.

[0025] Explanation of reference numerals in the attached figures: 1. Temperature sensor; 2. Directional control valve; 3.1. First pressure sensor; 3.2. Second pressure sensor; 4. Flow sensor; 5. Hydraulic motor; 6. Leakage flow sensor; 7. Speed ​​sensor; 12.1. First flow sensor; 12.2. Second flow sensor; 9. Hydraulic motor; 10. Temperature sensor in hydraulic motor circuit; 11. Pressure sensor in hydraulic motor circuit; 13. Hydraulic motor in hydraulic motor circuit. Detailed Implementation

[0026] The present invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0027] like Figure 1 As shown, this invention proposes a flow rate compensation method for hydraulic motor flow rate detection, comprising: Step S1: Construct a hydraulic motor circuit. Set a first flow sensor and a second flow sensor at the oil inlet and oil outlet of the hydraulic motor circuit, respectively. Obtain oil pressure data and oil temperature data at the oil inlet and oil outlet. Determine the initial flow compensation coefficient sequence of the oil inlet and oil outlet. Fit the initial flow compensation coefficient sequence based on the two-dimensional cubic spline interpolation method to obtain a three-dimensional spatial surface model in which the flow compensation coefficient changes continuously with oil pressure and oil temperature. Step S2: Obtain the hydraulic motor whose flow rate is to be detected. The hydraulic motor whose flow rate is to be detected has two working ports. Select any one of the working ports and set a flow sensor for the selected working port. Determine the flow compensation coefficient of the hydraulic motor whose flow rate is to be detected based on the three-dimensional spatial surface model. Perform numerical compensation on the flow rate of the hydraulic motor whose flow rate is to be detected according to the flow compensation coefficient.

[0028] The overall concept of this invention is as follows: In step S1, a hydraulic motor circuit for measurement and statistics is constructed. This hydraulic motor circuit is independent of the hydraulic motor system whose flow rate is to be detected. By setting two flow sensors suitable for the hydraulic motor circuit, a three-dimensional surface model is constructed in which the compensation coefficient continuously changes with hydraulic pressure and oil temperature. Based on the hydraulic pressure and oil temperature data, the compensation coefficient can be determined. For the hydraulic motor system whose flow rate is to be detected, this hydraulic motor system has only one flow sensor. If the port where the flow sensor is set is used as the oil inlet in the hydraulic motor system whose flow rate is to be detected, no compensation is required; if the port where the flow sensor is set is used as the oil return inlet in the hydraulic motor system whose flow rate is to be detected, the flow rate value detected by the flow sensor is compensated according to the compensation coefficient. In the prior art, because the hydraulic motor rotates forward and backward, the working oil port switches between the oil inlet and the oil return inlet. Therefore, the prior art often configures a flow sensor at each of the two working ports. This invention improves upon the existing technology's approach of configuring a flow sensor at both the oil inlet and return port, thereby reducing the need for a flow sensor suitable for the hydraulic motor circuit and lowering costs.

[0029] Step S1 involves acquiring hydraulic data and oil temperature data for the inlet and outlet ports, and determining the initial flow compensation coefficient sequence for the inlet and outlet ports, including: Step S11: Obtain the maximum oil supply pressure Pmax of the hydraulic motor circuit, determine the number of segments m according to the specifications of the hydraulic motor, and obtain the segment step size. The first sequence is obtained. ; In this embodiment, the value of m is determined based on, for example, the power of the hydraulic motor.

[0030] Step S12: For each element in the first sequence , All of them shall perform the following operations: The initial oil temperature T0 is taken as the oil temperature before the hydraulic motor circuit starts working, and the highest allowable oil temperature during operation is taken as the maximum oil temperature Tmax. The range [T0, Tmax] is divided into n temperature intervals to obtain the second sequence {Tnum}. That is, {T0, T0+} T0+2 ..., T0+n }, where T0+n =Tmax; For each temperature value in the second sequence, when the oil temperature in the hydraulic motor circuit reaches that temperature value, the flow rates at the inlet and outlet are obtained by the first and second flow sensors respectively, and recorded as follows: and Calculate the flow compensation between the two working ports. The calculation method is as follows: The initial flow compensation coefficient sequence is obtained. ={ },in , , , Each value in the initial flow compensation coefficient sequence represents a value corresponding to the oil supply pressure. With oil temperature The flow compensation coefficient, wherein each pressure value in the first sequence is also called a pressure node, and the first sequence with m pressure nodes can determine m-1 pressure intervals; each temperature value in the second sequence is also called a temperature node, and the second sequence with n+1 temperature nodes can determine n temperature intervals; Step S13: For the first sequence For each element in the list, perform the following operations: Under the given conditions, for each temperature value in the second sequence, the initial flow compensation coefficient sequence is fitted with a cubic function of the compensation coefficients with respect to the oil temperature using one-dimensional cubic spline interpolation, thus obtaining the first initial flow compensation sequence. , ; For the second sequence {Tnum}, i.e. {T0, T0+} T0+2 ..., T0+n Each element in} performs the following operation: Under the given conditions, for each pressure value in the first sequence, the initial flow compensation coefficient sequence is fitted with a cubic function of the compensation coefficient with respect to the oil supply pressure using one-dimensional cubic spline interpolation, thus obtaining the second initial flow compensation coefficient sequence. , .

[0031] In this embodiment, the compensation relationship only applies to the oil supply pressure. oil temperature To determine the flow compensation relationship between ports A and B under specific temperature and pressure conditions, the compensation coefficient needs to be obtained. A continuous surface model that varies with oil temperature and pressure conditions, i.e. .

[0032] Step S1, which involves fitting the initial flow compensation coefficient sequence using a two-dimensional cubic spline interpolation method to obtain a three-dimensional spatial surface model of the flow compensation coefficients continuously varying with oil pressure and oil temperature, includes: Step S14: For each first initial flow compensation sequence , All of them shall perform the following operations: For the first initial flow compensation sequence For each of the corresponding n temperature ranges, a compensation coefficient is constructed based on the oil temperature. The cubic function is obtained. in, They represent unknown coefficients, It is the oil supply pressure Under the condition of the first A cubic function is constructed from several temperature intervals, where {T0, ..., Tn} is the second sequence, and T is the independent variable representing the oil temperature. ; The following constraints are constructed for solving: get cubic function under certain conditions , , The cubic function of the i1th temperature interval at oil temperature is The value of time, for Time The compensation coefficients calculated at each temperature node. The cubic function of the nth temperature range at oil temperature is The value at time; for The compensation coefficient calculated at the nth temperature node. The cubic function of the i2th temperature interval at oil temperature is The value of time, The cubic function of the i2+1th temperature interval at oil temperature is The value of time, , They are respectively , The first derivative, , They are respectively , The second derivative, and All are preset to 0; In this embodiment, for the temperature part, there are 4n equations in the above formula abcd, which means 4n equations need to be solved. The first row of the constraint conditions has n+1 equations, and the second, third, and fourth rows correspond to the temperature nodes from the first to the n-1th (that is, the data nodes remaining after removing the two endpoints), so there are 3n-3 equations. Adding the two equations in the fifth row, there are exactly 4n equations.

[0033] Step S15: The first sequence It is denoted as {P0,……,Pm-1}, that is, there are m pressure nodes, corresponding to m-1 pressure intervals; For each second initial flow compensation coefficient sequence , All of them shall perform the following operations: For the second initial flow compensation coefficient sequence For each of the corresponding m-1 pressure ranges, a compensation coefficient is constructed based on the oil supply pressure. The cubic function is obtained.

[0034] in, They represent unknown coefficients, Oil temperature Under the condition of the first A cubic function constructed over a temperature range. The independent variable is the oil supply pressure. ; The following constraints are constructed for solving:

[0035] get cubic function under certain conditions ,in, , The cubic function of the j1-th pressure interval at the oil supply pressure is The value of time, for Time The compensation coefficients calculated for each pressure node. The cubic function of the (m-1)th pressure interval at the oil supply pressure is The value of time, for The compensation coefficient calculated at the (m-1)th pressure node. The cubic function of the j2th pressure interval at the oil supply pressure is The value of time, The cubic function of the (j2+1)th temperature range at the oil supply pressure is The value of time, , They are respectively , The first derivative, , They are respectively , The second derivative, and All are preset to 0; In this embodiment, the pressure part consists of 4m-4 equations, because there are m pressure nodes and n+1 temperature nodes.

[0036] Step S16: Based on the oil temperature Shaft, oil supply pressure is Shaft, compensation coefficient is Establish a spatial rectangular coordinate system based on the axes, and and By combining these parameters, a two-dimensional fitted surface model is obtained in which the compensation coefficient continuously varies with oil temperature and oil supply pressure.

[0037]

[0038] in, Indicates the first The temperature range and the first The compensation coefficient function within the rectangular region enclosed by several pressure intervals. Indicates the first The temperature node and the first Compensation coefficient at each pressure node. Indicates the first +1 temperature node and the first Compensation coefficient at each pressure node. Indicates the first The temperature node and the first +1 compensation coefficient at pressure nodes , Indicates the first +1 temperature node and the first +1 compensation coefficient at pressure nodes; , , The rectangular area enclosed by the four data nodes and the first The temperature range and the first The rectangular area enclosed by the pressure intervals is consistent; and ,in Indicates the first Temperature values ​​at each temperature node. Indicates the first Pressure values ​​at each pressure node, and ; Step S17: Based on the two-dimensional fitting surface model where the compensation coefficient continuously varies with oil temperature and oil supply pressure, obtain the three-dimensional spatial surface model where the compensation coefficient continuously varies with oil temperature and oil supply pressure. .

[0039] In this embodiment, step S16 will... and To combine, that is, in each adjacent Within the rectangular area enclosed by the data nodes, let and ,in Compensation coefficient within any rectangular area The two-dimensional surface model fitted from the temperature and pressure information of the hydraulic system is as follows:

[0040] In this invention, a compensation coefficient that continuously varies with temperature and pressure conditions is obtained. A three-dimensional surface model based on oil temperature and pressure information can be used to obtain the flow compensation relationship between ports A and B under arbitrary temperature and pressure conditions. In other words, by obtaining a set of temperature and pressure information, the corresponding compensation coefficient can be found. After compensating and converting the flow rate under low pressure, we can obtain the flow rate under high pressure.

[0041] Figure 3 A specific structure of a system with a hydraulic motor is disclosed.

[0042] In this invention, the hydraulic motor displacement test circuit diagram illustrates the specific application of the invention. Device 2 in the diagram is a three-position four-way valve. When the valve is open, the hydraulic fluid flows clockwise in the circuit. The high-pressure fluid flowing in from port A performs work and then flows out as low-pressure fluid. At this time, the flow sensor can directly measure the high-pressure flow rate without compensation. When the valve is open at an angle, the hydraulic fluid flows counterclockwise in the circuit. The high-pressure fluid flows in from port B and then flows out as low-pressure fluid. In this case, the flow sensor cannot directly measure the high-pressure flow rate, so the flow detection and compensation method proposed in this invention is used for compensation.

[0043] Step S2 includes: Step S21: Obtain the hydraulic motor with the flow rate to be detected. The hydraulic motor has two working ports. Select any one of the working ports and set a flow sensor for the selected working port. When the working port with the flow sensor is set as the oil inlet, no compensation is required, and the value measured by the flow sensor is output as the detection data, and the method ends. When the working port with the flow sensor is set as the oil outlet, the value measured by the flow sensor is recorded as... The real-time oil temperature T of the hydraulic motor with the flow rate to be detected is then measured by a temperature sensor, and the oil pressure P is measured by a pressure sensor at the oil inlet. Based on the three-dimensional spatial surface model, the current compensation coefficient of the hydraulic motor with the flow rate to be detected is determined. Proceed to step S22; Step S22: Obtain the leakage flow rate corresponding to the hydraulic motor whose flow rate is to be detected by the flow sensor for detecting leakage, and record it as... According to the current compensation coefficient Flow rate compensation is performed on the hydraulic motor whose flow rate is to be detected.

[0044] In this embodiment, Figure 3 The flow sensor is installed at port A. The direction of hydraulic oil flow determines the forward and reverse rotation of the hydraulic motor. If port A is used as the oil inlet (high pressure) at this time, no compensation is needed. If port A is used as the oil return port (low pressure) at this time, the flow rate at the high pressure port needs to be calculated by dividing by the compensation coefficient.

[0045] In actual hydraulic system operation, hydraulic motors may leak fluid. Therefore, a flow sensor is usually installed to detect whether the hydraulic motor is leaking, thereby performing comprehensive numerical compensation. The flow sensor for detecting leaks differs from the flow sensor installed at port A or port B. The flow meter in the hydraulic motor circuit must be extremely high-pressure resistant and highly accurate, while the flow meter for detecting leaks does not have requirements for high pressure resistance and high accuracy, and is low-cost; a regular flow meter is sufficient.

[0046] In this embodiment, as Figure 3 As shown, the flow rate of the high-pressure fluid flowing into port B is denoted as... The low-pressure fluid produced after the work is done mostly flows out from port A, and is measured by flow sensor 4, denoted as . In addition, there may be a small amount of oil leakage, which is measured by flow sensor 6 and recorded as follows: The high-pressure end flow rate It can be obtained from the following formula: This solves the problem of inconsistent flow detection benchmarks caused by using only one high-pressure resistant flow sensor in the hydraulic motor displacement test circuit.

[0047] This invention is not only applicable to the hydraulic system discussed herein, but also to other hydraulic systems that meet the background description.

[0048] The specific embodiments described above only illustrate the design principles of the present invention. The shapes and names of the components in this description may differ and are not limited. Therefore, those skilled in the art can modify or make equivalent substitutions to the technical solutions described in the foregoing embodiments; and these modifications and substitutions do not depart from the inventive spirit and technical solutions of the present invention, and should all fall within the protection scope of the present invention.

Claims

1. A flow rate compensation method for flow detection of a hydraulic motor, characterized in that, include: Step S1: Construct a hydraulic motor circuit. Set a first flow sensor and a second flow sensor at the oil inlet and oil outlet of the hydraulic motor circuit, respectively. Obtain oil pressure data and oil temperature data at the oil inlet and oil outlet. Determine the initial flow compensation coefficient sequence of the oil inlet and oil outlet. Fit the initial flow compensation coefficient sequence based on the two-dimensional cubic spline interpolation method to obtain a three-dimensional spatial surface model in which the flow compensation coefficient changes continuously with oil pressure and oil temperature. Step S2: Obtain the hydraulic motor whose flow rate is to be detected. The hydraulic motor whose flow rate is to be detected has two working ports. Select any one of the working ports and set a flow sensor for the selected working port. Determine the flow compensation coefficient of the hydraulic motor whose flow rate is to be detected based on the three-dimensional spatial surface model. Perform numerical compensation on the flow rate of the hydraulic motor whose flow rate is to be detected according to the flow compensation coefficient. Step S2 includes: Step S21: Obtain the hydraulic motor with the flow rate to be detected. The hydraulic motor has two working ports. Select any one of the working ports and set a flow sensor for the selected working port. When the working port with the flow sensor is set as the oil inlet, no compensation is required, and the value measured by the flow sensor is output as the detection data, and the method ends. When the working port with the flow sensor is set as the oil outlet, the value measured by the flow sensor is recorded as... The real-time oil temperature T of the hydraulic motor with the flow rate to be detected is then measured by a temperature sensor, and the oil pressure P is measured by a pressure sensor at the oil inlet. Based on the three-dimensional spatial surface model, the current compensation coefficient of the hydraulic motor with the flow rate to be detected is determined. Proceed to step S22; Step S22: Obtain the leakage flow rate corresponding to the hydraulic motor whose flow rate is to be detected by the flow sensor for detecting leakage, and record it as... According to the current compensation coefficient Flow rate compensation is performed on the hydraulic motor whose flow rate is to be detected; Based on the current compensation coefficient The hydraulic motor whose flow rate is to be detected is subjected to flow rate compensation, and the compensated flow rate value is: 。 2. The method as described in claim 1, characterized in that, Step S1 involves acquiring hydraulic data and oil temperature data for the inlet and outlet ports, and determining the initial flow compensation coefficient sequence for the inlet and outlet ports, including: Step S11: Obtain the maximum oil supply pressure Pmax of the hydraulic motor circuit, determine the number of segments m according to the specifications of the hydraulic motor, and obtain the segment step size. The first sequence is obtained. ; Step S12: For each element in the first sequence , All of them shall perform the following operations: The initial oil temperature T0 is taken as the oil temperature before the hydraulic motor circuit starts working, and the highest allowable oil temperature during operation is taken as the highest oil temperature T. max ; will [T0, T max Divide the temperature range into n intervals to obtain the second sequence {T}. num }, That is, {T0, T0+} T0+2 ..., T0+n }, where T0+n = T max For each temperature value in the second sequence, when the oil temperature in the hydraulic motor circuit reaches that temperature value, the flow rates at the inlet and outlet are obtained by the first and second flow sensors respectively, and recorded as follows: and Calculate the flow compensation between the two working ports. The calculation method is as follows: The initial flow compensation coefficient sequence is obtained. ={ },in , , , Each value in the initial flow compensation coefficient sequence represents a value corresponding to the oil supply pressure. With oil temperature The flow compensation coefficient, wherein each pressure value in the first sequence is also called a pressure node, and the first sequence with m pressure nodes can determine m-1 pressure intervals; each temperature value in the second sequence is also called a temperature node, and the second sequence with n+1 temperature nodes can determine n temperature intervals; Step S13: For the first sequence For each element in the list, perform the following operations: Under the given conditions, for each temperature value in the second sequence, the initial flow compensation coefficient sequence is fitted with a cubic function of the compensation coefficients with respect to the oil temperature using one-dimensional cubic spline interpolation, thus obtaining the first initial flow compensation sequence. , ; For the second sequence {T num }, that is, {T0, T0+ T0+2 ..., T0+n Each element in} performs the following operation: Under the given conditions, for each pressure value in the first sequence, the initial flow compensation coefficient sequence is fitted with a cubic function of the compensation coefficient with respect to the oil supply pressure using one-dimensional cubic spline interpolation, thus obtaining the second initial flow compensation coefficient sequence. , .

3. The method as described in claim 2, characterized in that, Step S1, which involves fitting the initial flow compensation coefficient sequence using a two-dimensional cubic spline interpolation method to obtain a three-dimensional spatial surface model of the flow compensation coefficients continuously varying with oil pressure and oil temperature, includes: Step S14: For each first initial flow compensation sequence , All of them shall perform the following operations: For the first initial flow compensation sequence For each of the corresponding n temperature ranges, a compensation coefficient is constructed based on the oil temperature. The cubic function is obtained. ； in, They represent unknown coefficients, It is the oil supply pressure Under the condition of the first A cubic function is constructed over a temperature range, {T0,……,T n } represents the second sequence, where T is the independent variable, representing the oil temperature. ; The following constraints are constructed for solving: ； get cubic function under certain conditions , , The cubic function of the i1th temperature interval at oil temperature is The value of time, for Time The compensation coefficients calculated at each temperature node. The cubic function of the nth temperature range at oil temperature is The value at time; for The compensation coefficient calculated at the nth temperature node. The cubic function of the i2th temperature interval at oil temperature is The value of time, The cubic function of the i2+1th temperature interval at oil temperature is The value of time, , They are respectively , The first derivative, , They are respectively , The second derivative, and All are preset to 0; Step S15: The first sequence Let it be denoted as {P0, ..., P} m-1 There are m pressure nodes, corresponding to m-1 pressure ranges. For each second initial flow compensation coefficient sequence , All of them shall perform the following operations: For the second initial flow compensation coefficient sequence For each of the corresponding m-1 pressure ranges, a compensation coefficient is constructed based on the oil supply pressure. The cubic function is obtained. ； in, They represent unknown coefficients, Oil temperature Under the condition of the first A cubic function constructed over a temperature range. The independent variable is the oil supply pressure. ; The following constraints are constructed for solving: ； get cubic function under certain conditions ,in, , The cubic function of the j1-th pressure interval at the oil supply pressure is The value of time, for Time The compensation coefficients calculated for each pressure node. The cubic function of the (m-1)th pressure interval at the oil supply pressure is The value of time, for The compensation coefficient calculated at the (m-1)th pressure node. The cubic function of the j2th pressure interval at the oil supply pressure is The value of time, The cubic function of the (j2+1)th temperature range at the oil supply pressure is The value of time, , They are respectively , The first derivative, , They are respectively , The second derivative, and All are preset to 0; Step S16: Based on the oil temperature Shaft, oil supply pressure is Shaft, compensation coefficient is Establish a spatial rectangular coordinate system based on the axes, and and By combining these parameters, a two-dimensional fitted surface model is obtained in which the compensation coefficient continuously varies with oil temperature and oil supply pressure. ; ； in, Indicates the first The temperature range and the first The compensation coefficient function within the rectangular region enclosed by several pressure intervals. Indicates the first The temperature node and the first Compensation coefficient at each pressure node. Indicates the first +1 temperature node and the first Compensation coefficient at each pressure node. Indicates the first The temperature node and the first +1 compensation coefficient at pressure nodes Indicates the first +1 temperature node and the first +1 compensation coefficient at pressure nodes; and ,in Indicates the first Temperature values ​​at each temperature node. Indicates the first Pressure values ​​at each pressure node, and ; Step S17: Based on the two-dimensional fitting surface model where the compensation coefficient continuously varies with oil temperature and oil supply pressure, obtain the three-dimensional spatial surface model where the compensation coefficient continuously varies with oil temperature and oil supply pressure. 。 4. The method according to any one of claims 2-3, characterized in that, The value of m is determined based on the power of the hydraulic motor.

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