A control system and method for efficient utilization of a winch hydraulic system pump and motor

Abstract

A control system and method for efficient utilization of a winch hydraulic system's pump and motor, which relate to the field of hydraulic system control. The control system includes: a hydraulic pump, a winch reversing valve, a balance valve, a winch motor, a winch motor speed sensor, a controller, a first pressure sensor, and a second pressure sensor. The optimal efficiency model of the winch system's pump and motor is fitted by the orthogonal experiment method and the least squares method. The motor speed and the load change of the winch system are detected in real time through the speed sensor and the pressure sensor, and the system pressure is detected in real time. The controller processes the detection signals and adjusts the motor displacement according to the detection signals, so that the system adjusts in real time according to the load change and is in the optimal efficiency. The present invention can detect the load change during the operation of the winch hydraulic system, and adjust the displacement of the motor according to the load change, so that the product of the efficiencies of the hydraulic pump and the hydraulic motor is always at the highest point, to ensure that the comprehensive efficiency of the winch hydraulic system is in the high-efficiency zone.

Description

Technical Field

[0001] The present invention relates to the technical field of hoisting hydraulic systems, and particularly to a control system and method for efficient utilization of pump motors in hoisting hydraulic systems. Background Art

[0002] The hoisting hydraulic system is a control device used in construction machinery to realize the lifting and lowering of heavy objects. Although in some construction machinery such as cranes, the load of the hoisting system is constant during operation, there are also some construction machinery such as diaphragm walls and rotary drilling rigs. When operating in the hole, due to the influence of hole wall friction, the load increases. More seriously, when working in a water hole filled with mud, the coupling relationship between the movement state of the drill pipe and the mud resistance exists, which will destroy the balance state of the load and cause load pulsation caused by resistance changes. In these working conditions, the traditional hoisting system cannot well match the load changes, resulting in energy loss of the system and low efficiency of the hoisting hydraulic system. Summary of the Invention

[0003] In order to reduce the energy loss of the hoisting hydraulic system during operation and improve the overall efficiency of the system, the present invention provides a control system and method for efficient utilization of pump motors in hoisting hydraulic systems. This method can intelligently adjust the displacement of the motor according to different main hoisting loads to adjust the efficiency of the hydraulic pump and hydraulic motor, so that the overall efficiency of the pump and motor is in the high-efficiency zone.

[0004] To achieve the above object, the present invention is implemented by the following technical solutions:

[0005] The present invention provides a control system for efficient utilization of pump motors in a hoisting hydraulic system. The system includes a hydraulic pump, a hoisting reversing valve, a balance valve, a hoisting motor, a speed sensor, a controller, a first pressure sensor, and a second pressure sensor;

[0006] The hydraulic pump is connected to the hoisting reversing valve. One port of the hoisting reversing valve is connected to one end of the hoisting motor through balance valves at both ends, and the other port of the hoisting reversing valve is connected to the other end of the hoisting motor;

[0007] The speed sensor is connected to the hoisting motor for real-time detection and indication identification of the motor speed;

[0008] One end of the first pressure sensor is connected to the left oil circuit of the hoisting motor, and the other end of the first pressure sensor is connected to the controller; one end of the second pressure sensor is connected to the right oil circuit of the hoisting motor, and the other end of the second pressure sensor is connected to the controller; the first pressure sensor and the second pressure sensor are used for real-time detection of the inlet and outlet pressures of the hoisting motor;

[0009] One end of the controller is connected to the speed sensor, the first pressure sensor and the second pressure sensor, and the other end of the controller is connected to the winch motor. The controller is used to adjust the displacement of the motor according to the optimal efficiency characteristic model for different winch loads, so as to adjust the product of the pump efficiency and the winch motor efficiency, so that the comprehensive efficiency of the pump and the winch motor is in the high efficiency zone; the optimal efficiency characteristic model reflects the approximate linear relationship between the load and the motor displacement under the highest comprehensive efficiency.

[0010] Furthermore, the optimal efficiency characteristic model is obtained in the following manner:

[0011] The data pair of load pressure and motor displacement at the optimal efficiency is obtained by orthogonal experimental method;

[0012] The approximate linear relationship between load and motor displacement at the highest efficiency is fitted by the least squares method to obtain the optimal efficiency characteristic model.

[0013] Furthermore, the controller includes an adaptive fuzzy PID controller; the adaptive fuzzy PID controller takes the deviation e and the deviation change rate ec of the system efficiency as input.

[0014] Furthermore, when the winch reversing valve is in the right position, the winch hydraulic system is in a load lifting condition; when the winch reversing valve is in the left position, the winch hydraulic system is in a load lowering condition.

[0015] Furthermore, the rotation speed sensor is a rotation speed sensor provided by the hoisting motor.

[0016] The present invention also provides a control method for efficient utilization of a winch hydraulic system pump motor, which is applied to the above control system, wherein the controller controls the displacement of the winch motor in the winch hydraulic system according to the following steps:

[0017] Receiving the inlet and outlet pressures of the hoisting motor detected by the first pressure sensor and the second pressure sensor;

[0018] Calculating the inlet and outlet pressure difference to obtain a load signal, and performing low-pass filtering on the load signal;

[0019] Adaptive analog PID control is performed based on the load signal after low-pass filtering and the optimal efficiency characteristic model to adjust the displacement of the winch motor according to the load;

[0020] Acquire the motor speed detected by the speed sensor after the motor displacement is adjusted, and the inlet and outlet pressures of the hoisting motor detected by the first pressure sensor and the second pressure sensor after the adjustment;

[0021] Calculate the hydraulic pump efficiency and the winch motor efficiency based on the adjusted motor speed and the adjusted inlet and outlet pressures of the winch motor;

[0022] Calculate the product of the pump efficiency and the motor efficiency to obtain the adjusted system efficiency; determine whether the adjusted system efficiency is in the high-efficiency region;

[0023] Perform multiple iterations on the adjustment that meets the system boundary conditions until the iteration termination condition is satisfied. The iteration termination condition is that the system comprehensive efficiency reaches the global optimal value of this iteration cycle, and output the optimal displacement value.

[0024] Further, before using the adaptive fuzzy PID controller for control, it also includes: setting the system boundary conditions, including the motor displacement V p Satisfying V min <V p <V max , where V min is the minimum motor displacement, and V max is the maximum motor displacement; the motor speed n m Satisfying n min <n m <n max , where n min is the minimum motor speed, and n max is the maximum motor speed; the system pressure P p <P γ .

[0025] The beneficial effects of the present invention are as follows: The present invention can detect the load change during the working process of the hoisting hydraulic system, and adjust the displacement of the motor according to the load change, so that the product of the efficiencies of the hydraulic pump and the hydraulic motor is always at the highest point to ensure that the comprehensive efficiency of the hoisting hydraulic system is in the high-efficiency region. In the prior art, the pressure in the motor bearing chamber is usually kept constant by adjusting the motor displacement, while the present invention adjusts the motor displacement to regulate the product of the efficiencies of the pump and the motor, and keeps the comprehensive efficiency of the system in the high-efficiency region. Compared with the prior art, the solution of the present invention is more accurate and comprehensive in terms of control effect. Brief Description of the Drawings

[0026] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for the description of the embodiments or the prior art. Obviously, the drawings in the following description are some embodiments of the present invention. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0027] Figure 1 It is the structure and hydraulic schematic diagram of the hoisting hydraulic system in the embodiment of the present invention;

[0028] The figure includes: 1-hydraulic pump, 2-winch reversing valve, 3-balance valve, 4-winch motor, 5-winch motor with speed sensor, 6-controller, 7-pressure sensor, 8-pressure sensor;

[0029] Figure 2 It is a control flow chart of the winch hydraulic system in an embodiment of the present invention. DETAILED DESCRIPTION

[0030] In order to enable those skilled in the art to better understand the scheme of the present invention, the technical scheme in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work should fall within the scope of protection of the present invention.

[0031] It should be noted that the terms "first", "second", etc. in the specification and claims of the present invention and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. It should be understood that the data used in this way can be interchanged where appropriate, so that the embodiments of the present invention described herein can be implemented in an order other than those illustrated or described herein. In addition, the terms "including" and "having" and any variations thereof are intended to cover non-exclusive inclusions, for example, a process, method, system, product or device that includes a series of steps or units is not necessarily limited to those steps or units that are clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices.

[0032] like Figure 1 As shown, the control system of the winch hydraulic system in the embodiment of the present invention includes a hydraulic pump 1, a winch reversing valve 2, a balance valve 3, a winch motor 4, a speed sensor 5, a controller 6, a first pressure sensor 7 and a second pressure sensor 8.

[0033] Among them, the hydraulic pump 1, the hoisting reversing valve 2, the balance valve 3 and the hoisting motor 4 jointly complete the hoisting hydraulic function. The hydraulic pump 1 is connected to the hoisting reversing valve 2, one port of the hoisting reversing valve 2 is connected to one end of the hoisting motor 4 through the two-end balance valve 3, and the other port of the hoisting reversing valve 2 is connected to the other end of the hoisting motor 4. When the hoisting reversing valve 2 is in the right position, the hoisting hydraulic system is in the load lifting condition, and when the hoisting reversing valve 2 is in the left position, the hoisting hydraulic system is in the load lowering condition.

[0034] The speed sensor 5 is a speed sensor provided by the hoisting motor 4 and is used for real-time detection and indication identification of the motor speed.

[0035] One end of the first pressure sensor 7 is connected to the left oil circuit of the hoist motor 4, and the other end of the first pressure sensor 7 is connected to the controller 6; one end of the second pressure sensor 8 is connected to the right oil circuit of the hoist motor 4, and the other end of the second pressure sensor 8 is connected to the controller 6; the first pressure sensor 7 and the second pressure sensor 8 are used to detect the inlet and outlet pressures of the hoist motor 4 in real time.

[0036] One end of the controller 6 is connected to the torque and speed sensor 5 and the pressure and flow sensor 7, and the other end of the controller 6 is connected to the hoist motor 4. The controller 6 is used to perform arithmetic processing on the speed signal, perform low-pass filtering on the pressure signal, and adjust the displacement of the hoist motor 4. The controller 6 adjusts the displacement of the motor according to the optimal efficiency characteristic model for different hoist loads, so as to adjust the product of the pump efficiency and the hoist motor efficiency, and make the combined efficiency of the pump and the hoist motor in the high-efficiency area; the optimal efficiency characteristic model reflects the approximate linear relationship between the load and the motor displacement at the highest combined efficiency.

[0037] Since the pump and motor cannot reach the highest efficiency point at the same time, the highest point of the product of the pump and motor efficiencies corresponding to different pump and motor pressures is the optimal point of the combined efficiency of the pump and motor. Therefore, the data pairs of the load pressure and the motor displacement at the optimal efficiency can be obtained by the orthogonal experiment method, and the approximate linear relationship between the load and the motor displacement at the highest efficiency can be fitted by the least square method to fit the optimal efficiency characteristic model and set the Figure 1 controller 6 in it. The pressure sensor detects the inlet and outlet pressures of the motor and transmits them back to the controller for calculation to obtain the real-time load state during the service stage. Due to the existence of load fluctuations, in order to avoid the resonance between the adjustment frequency of the motor displacement and the natural frequency of the system, the load signal needs to be low-pass filtered, and then the current motor displacement is adjusted according to the processed load signal. After adjusting the motor displacement, calculate the product of the pump and motor efficiencies by detecting the motor speed and the system pressure, and judge whether the adjusted system combined efficiency is in the high-efficiency area. Repeatedly iterate the adjustment strategy that meets the boundary conditions until the iteration termination condition is met, that is, when the system combined efficiency reaches the global optimal value of this iteration cycle, stop the iteration and output the optimal displacement value. Consider the fuzzy control rules from aspects such as the stability, response speed, overshoot, and stability accuracy of the system. An adaptive fuzzy PID controller is constructed with the deviation e and the deviation change rate ec of the system efficiency as the inputs, which can meet the requirements of self-tuning of PID parameters for different e and ec at different times. Compared with the traditional PID control, the fuzzy PID control is more suitable for linear control systems with dynamic characteristics that do not change with time. Therefore, the entire control process can be carried out by the fuzzy PID control method to ensure the stability and rapidity of the entire control process.

[0038] Specifically, as Figure 2 shown, the controller 6 controls the displacement of the hoist motor in the hoist hydraulic system according to the following steps:

[0039] S1. Receive the inlet and outlet pressures of the hoist motor 4 detected by the second pressure sensor 8 and the first pressure sensor 7;

[0040] Under different load conditions, the first pressure sensor 7 and the second pressure sensor 8 are used to detect the pressures at different ports. Specifically, in the load lifting condition, the first pressure sensor 7 detects the motor outlet pressure, and the second pressure sensor 8 detects the motor inlet pressure; in the load lowering condition, the first pressure sensor 7 detects the motor inlet pressure, and the second pressure sensor 8 detects the motor outlet pressure.

[0041] S2. Calculate the pressure difference between the inlet and outlet, obtain the load signal, and perform low-pass filtering on the load signal;

[0042] When calculating the pressure difference between the inlet and outlet, subtract the motor outlet pressure from the motor inlet pressure to obtain the load signal; due to the existence of load fluctuations, in order to avoid resonance between the adjustment frequency of the motor displacement and the natural frequency of the system, low-pass filtering needs to be performed on the load signal.

[0043] S3. Perform adaptive analog PID control based on the load signal after low-pass filtering and the optimal efficiency characteristic model, and adjust the displacement of the hoist motor 4 according to the load;

[0044] Among them, the optimal efficiency characteristic model is obtained in the following way: obtain the data pairs of the load pressure and the motor displacement under the optimal efficiency through the orthogonal experiment method, and fit the approximate linear relationship between the load and the motor displacement under the highest efficiency by the least square method to fit the optimal efficiency characteristic model;

[0045] The adaptive fuzzy PID controller is constructed with the deviation e and the deviation change rate ec of the system efficiency as inputs, and can meet the requirements of self-tuning of the PID parameters for different e and ec at different times.

[0046] In specific implementation, when using the adaptive fuzzy PID controller for control, system boundary conditions also need to be set, including the motor displacement V p Satisfy V min <V p <V max where V min is the minimum motor displacement, V max is the maximum motor displacement; the motor speed n m Satisfy n min <n m <n max where n min is the minimum motor speed, n max is the maximum motor speed; the system pressure P p <P γEnter the optimal efficiency model and boundary conditions into the fuzzy PID controller, use the load signal as the input, and the motor displacement adjustment signal as the output for fuzzy PID control; judge the load condition, compare it with the optimal efficiency model, and adjust the motor displacement V according to the load within the boundary conditions m .

[0047] S4. Obtain the motor speed after adjusting the motor displacement detected by the speed sensor 5, and the inlet and outlet pressures of the adjusted hoist motor 4 detected by the first pressure sensor 7 and the second pressure sensor 8;

[0048] S5. Calculate the hydraulic pump efficiency and the hoist motor efficiency according to the adjusted motor speed and the inlet and outlet pressures of the adjusted hoist motor 4;

[0049] Among them, the calculation method of the motor efficiency is:

[0050]

[0051] In the formula: P m is the pressure difference between the inlet and outlet of the hydraulic motor (MPa); V m is the displacement of the hydraulic motor (L / r); n m is the speed of the hydraulic motor (r / s); ω m is the angular velocity of the hydraulic motor (1 / s); T m is the actual output torque of the hydraulic motor (N·m).

[0052] The calculation method of the pump efficiency is:

[0053]

[0054] In the formula: P p is the pressure difference between the inlet and outlet of the hydraulic pump (MPa); V p is the displacement of the hydraulic pump (L / r); n p is the speed of the hydraulic pump (r / s); ω p is the angular velocity of the hydraulic pump (1 / s); T p is the actual input torque of the hydraulic pump (N·m).

[0055] S6. Calculate the product of the pump efficiency and the motor efficiency to obtain the adjusted system efficiency; judge whether the adjusted system efficiency is in the high-efficiency area;

[0056] S7. If not, repeat the above detection and adjustment process;

[0057] S8. If so, the hoist hydraulic system works normally.

[0058] For the convenience of understanding, the control processes under two load conditions are described in detail below.

[0059] like Figure 1-2 As shown, the reversing valve 2 is switched to the right position, and the oil supplied by the hydraulic pump 1 flows to the hoisting motor 4 through the one-way valve in the balance valve 3. At this time, the hoisting system is in the load lifting condition. The pressure sensor 8 detects the inlet pressure of the hoisting motor 4 and inputs the signal into the controller 6. The pressure sensor 7 detects the outlet pressure of the hoisting motor 4 and inputs the signal into the controller 6. The controller 6 determines the load condition by calculating the inlet and outlet pressure difference, and performs low-pass filtering on the load signal to avoid system resonance. The controller 6 compares the load condition with the optimal efficiency characteristic model, adjusts the displacement of the hoisting motor 4, and detects the motor speed after adjusting the motor displacement through the speed sensor 5 provided by the hoisting motor. The pressure sensor 7 and the pressure sensor 8 detect the adjusted system pressure. The controller 6 calculates the efficiency product of the hydraulic pump 1 and the hoisting motor 4 according to the motor speed and the system pressure, and determines whether the adjusted system efficiency is in the high efficiency zone. The above detection and adjustment process is repeated until the comprehensive efficiency of the system reaches the optimal efficiency.

[0060] like Figure 1-2 As shown, the reversing valve 2 is switched to the left position, the hydraulic pump 1 supplies oil to the hoisting motor 4 through the left oil circuit, and the motor outlet oil flows back to the oil tank through the overflow valve of the balance valve 3. At this time, the hoisting system is in the load lowering condition. The pressure sensor 7 detects the inlet pressure of the hoisting motor 4 and inputs the signal into the controller 6. The pressure sensor 8 detects the outlet pressure of the hoisting motor 4 and inputs the signal into the controller 6. The controller 6 determines the load condition by calculating the inlet and outlet pressure difference, and performs low-pass filtering on the load signal to avoid system resonance. The controller 6 compares the load condition with the optimal efficiency characteristic model, adjusts the displacement of the hoisting motor 4, and detects the motor speed after adjusting the motor displacement through the hoisting motor's own speed sensor 5. The pressure sensor 7 and the pressure sensor 8 detect the adjusted system pressure. The controller 6 calculates the efficiency product of the hydraulic pump 1 and the hoisting motor 4 according to the motor speed and the system pressure, and determines whether the adjusted system efficiency is in the high efficiency zone. The above detection and adjustment process is repeated until the overall efficiency of the system reaches the optimal efficiency.

[0061] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A control system for efficient utilization of a pump motor in a hoisting hydraulic system, characterized in that The system comprises a hydraulic pump (1), a winch reversing valve (2), a balance valve (3), a winch motor (4), a rotation speed sensor (5), a controller (6), a first pressure sensor (7) and a second pressure sensor (8); The hydraulic pump (1) is connected to the hoisting reversing valve (2), one port of the hoisting reversing valve (2) is connected to one end of the hoisting motor (4) through a two-end balancing valve (3), and the other port of the hoisting reversing valve (2) is connected to the other end of the hoisting motor (4); The rotation speed sensor (5) is connected to the hoisting motor (4) and is used for real-time detection and indication identification of the motor rotation speed; One end of the first pressure sensor (7) is connected to the left oil circuit of the hoisting motor (4), and the other end of the first pressure sensor (7) is connected to the controller (6); one end of the second pressure sensor (8) is connected to the right oil circuit of the hoisting motor (4), and the other end of the second pressure sensor (8) is connected to the controller (6); the first pressure sensor (7) and the second pressure sensor (8) are used to detect the inlet and outlet pressures of the hoisting motor (4) in real time; One end of the controller (6) is connected to the rotation speed sensor (5), the first pressure sensor (7) and the second pressure sensor (8), and the other end of the controller (6) is connected to the hoisting motor (4). The controller (6) is used to adjust the displacement of the motor according to the optimal efficiency characteristic model for different hoisting loads, so as to adjust the product of the pump efficiency and the hoisting motor efficiency, so that the comprehensive efficiency of the pump and the hoisting motor is in a high efficiency zone; the optimal efficiency characteristic model reflects the approximate linear relationship between the load and the motor displacement at the highest comprehensive efficiency; The optimal efficiency characteristic model is obtained in the following manner: The data pair of load pressure and motor displacement at the optimal efficiency is obtained by orthogonal experimental method; The approximate linear relationship between load and motor displacement at the highest efficiency is fitted by the least square method to obtain the optimal efficiency characteristic model; When the winch reversing valve (2) is in the right position, the winch hydraulic system is in a load lifting condition; when the winch reversing valve (2) is in the left position, the winch hydraulic system is in a load lowering condition.

2. The control system for efficient utilization of the pump motor in a hoisting hydraulic system according to claim 1, wherein The controller (6) includes an adaptive fuzzy PID controller; the adaptive fuzzy PID controller takes the deviation e of system efficiency and the deviation change rate ec as input.

3. The control system for efficient utilization of the pump motor in the hoisting hydraulic system according to claim 1, characterized in that, The rotation speed sensor (5) is a rotation speed sensor provided by the hoisting motor (4).

4. A control method for efficient utilization of a hoisting hydraulic system pump motor, characterized in that, The control system according to any one of claims 1 to 3 is characterized in that the controller controls the displacement of the hoisting motor in the hoisting hydraulic system according to the following steps: Receiving the inlet and outlet pressures of the hoisting motor (4) detected by the first pressure sensor (7) and the second pressure sensor (8); Calculating the inlet and outlet pressure difference to obtain a load signal, and performing low-pass filtering on the load signal; Adaptive analog PID control is performed based on the load signal processed by low-pass filtering and the optimal efficiency characteristic model, and the displacement of the hoisting motor (4) is adjusted according to the load; Obtain the motor speed after adjusting the motor displacement detected by the rotational speed sensor (5), and the inlet and outlet pressures of the adjusted hoist motor (4) detected by the first pressure sensor (7) and the second pressure sensor (8); Calculate the hydraulic pump efficiency and the hoist motor efficiency based on the adjusted motor speed and the inlet and outlet pressures of the adjusted hoist motor (4); Calculate the product of the pump efficiency and the motor efficiency to obtain the adjusted system efficiency; determine whether the adjusted system efficiency is in the high-efficiency region; Perform multiple iterations on the adjustment that meets the system boundary conditions until the iteration termination condition is satisfied. The iteration termination condition is that the system comprehensive efficiency reaches the global optimal value of this iteration cycle, and output the optimal displacement value.

5. The control method for efficient utilization of a winch hydraulic system pump motor according to claim 4, characterized in that, Before using the adaptive fuzzy PID controller for control, it also includes: setting the system boundary conditions, including the motor displacement V p Meet V min ＜V p ＜V max , V min is the minimum motor displacement, V max is the maximum motor displacement; the motor speed n m Meet n min ＜n m ＜ n max , n min is the minimum motor speed, n max is the maximum motor speed; the system pressure P p ＜P γ .

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