CN113775603A - Electro-hydraulic multi-actuator flow control system and method - Google Patents
Electro-hydraulic multi-actuator flow control system and method Download PDFInfo
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
- F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
- F15B21/00—Common features of fluid actuator systems; Fluid-pressure actuator systems or details thereof, not covered by any other group of this subclass
- F15B21/001—Servomotor systems with fluidic control
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
- F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
- F15B21/00—Common features of fluid actuator systems; Fluid-pressure actuator systems or details thereof, not covered by any other group of this subclass
- F15B21/08—Servomotor systems incorporating electrically operated control means
- F15B21/087—Control strategy, e.g. with block diagram
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
- F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
- F15B2211/00—Circuits for servomotor systems
- F15B2211/20—Fluid pressure source, e.g. accumulator or variable axial piston pump
- F15B2211/205—Systems with pumps
- F15B2211/20576—Systems with pumps with multiple pumps
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
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- F15B2211/00—Circuits for servomotor systems
- F15B2211/40—Flow control
- F15B2211/465—Flow control with pressure compensation
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- F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
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- F15B2211/00—Circuits for servomotor systems
- F15B2211/60—Circuit components or control therefor
- F15B2211/605—Load sensing circuits
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
- F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
- F15B2211/00—Circuits for servomotor systems
- F15B2211/60—Circuit components or control therefor
- F15B2211/63—Electronic controllers
- F15B2211/6303—Electronic controllers using input signals
- F15B2211/6306—Electronic controllers using input signals representing a pressure
- F15B2211/6313—Electronic controllers using input signals representing a pressure the pressure being a load pressure
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
- F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
- F15B2211/00—Circuits for servomotor systems
- F15B2211/60—Circuit components or control therefor
- F15B2211/665—Methods of control using electronic components
- F15B2211/6656—Closed loop control, i.e. control using feedback
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
- F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
- F15B2211/00—Circuits for servomotor systems
- F15B2211/70—Output members, e.g. hydraulic motors or cylinders or control therefor
- F15B2211/71—Multiple output members, e.g. multiple hydraulic motors or cylinders
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
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- F15B2211/00—Circuits for servomotor systems
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Abstract
An electro-hydraulic multi-actuator flow control system comprises a power source, a main hydraulic pump, a main safety valve and a main oil path PLOil return path TLThe hydraulic control system comprises a main control valve, a hydraulic actuator, a load detection proportional valve, a valve core displacement sensor, a first pressure sensor, a second pressure sensor, a third pressure sensor and a global controller; load detection proportional valve oil inlet connection main oil way PL(ii) a The valve core displacement sensor is characterized in that a through shaft is arranged on a valve core of the load detection proportional valve or integrated on a proportional electromagnet; pressure sensor and main oil way PLCommunicating; the second pressure sensor and the third pressure sensor are respectively communicated with two cavities of the hydraulic actuator; the output signals of the first pressure sensor, the second pressure sensor and the third pressure sensor and the output signal of the load detection proportional valve spool displacement sensor are connected to the input end of the global controller; the signal output end of the global controller is connected with the proportion of the load detection proportional valveThe swing angle control end of electro-magnet and main hydraulic pump.
Description
Technical Field
The invention belongs to the technical field of hydraulic pressure, relates to a multi-actuator electro-hydraulic control system for engineering machinery, and particularly relates to an electro-hydraulic system and method adopting a closed-loop flow matching technology.
Technical Field
With the rapid development of engineering machinery, the problems of environmental protection and energy crisis are increasingly prominent, and meanwhile, the requirement of people on the operation comfort is higher and higher, and the engineering machinery with high reliability, high efficiency, energy conservation and good control performance becomes a hotspot of market demand and research. At present, engineering machinery generally adopts an internal combustion engine to drive a hydraulic pump as a power source, power is distributed and transmitted through a multiway valve and a hydraulic pipeline, and an electro-hydraulic multi-actuator system for controlling a plurality of actuators to perform composite actions mainly comprises several typical hydraulic control technologies such as negative flow, positive flow, load sensitivity and the like.
The traditional negative flow technology needs to detect the discharge capacity of a pressure control pump before an orifice, and the system has lag in response and large pressure fluctuation. The traditional positive flow technology adopts a shuttle valve group to screen the highest pilot pressure from each group of actions to control the pump displacement, the highest pilot pressure is unchanged, the pump displacement is unchanged, when a low-load actuator intervenes in the action, the rated pump flow needs to be redistributed, the problem that the output flow of a main pump is not matched with the required flow of the actuator exists, and the pressure and the flow of the actuator easily fluctuate. The traditional load sensing technology adopts variable pump pressure closed-loop control and self-adaptive control of the pressure and flow of a system, has the advantages of good composite operability, fine adjustment performance and the like, and is widely applied to engineering machinery. However, the system has problems of oscillation, response lag and the like due to long pipeline transmission of a system pressure feedback system, and stability and operation performance are influenced.
The existing solution is to adopt an electro-hydraulic flow matching mode of synchronous control of a pump valve, which can basically eliminate the phenomenon of a pump lagging valve in the control of the traditional load-sensitive system, does not need pressure feedback closed-loop control, greatly improves the dynamic performance and energy saving, and simultaneously considers the energy saving performance and the control performance. However, in practice, the system has uncertain parameters such as rotation speed, temperature, pump leakage, valve port gain and the like, so that the accurate and dynamic matching of the flow rate of the hydraulic pump is difficult, and the problems of over-flow matching (causing pressure impact and energy loss) or under-flow matching (reducing speed control precision and deteriorating operability) are easily caused. Therefore, how to control the accurate oil supply of the hydraulic pump according to the requirement is a key difficulty and a research focus of the electro-hydraulic flow matching technology, and is a problem to be solved by the invention.
Disclosure of Invention
In order to solve the problems, the invention aims to provide an electro-hydraulic control system and method capable of accurately matching the flow of a main pump from the practical situation.
In order to achieve the purpose, the invention adopts the following technical scheme: an electro-hydraulic multi-actuator flow control system comprises a power source, a main hydraulic pump, a main safety valve and a main oil path PLOil return path TLThe power source drives the main hydraulic pump coaxially, and an oil outlet and a main oil path P of the main hydraulic pumpLThe oil inlet of the main safety valve is communicated, the oil outlet of the main safety valve is communicated with the oil tank, and the oil inlet and the oil outlet of the main control valve are respectively communicated with the main oil way PLOil return path TLThe working oil path of the main control valve is respectively communicated with two cavities of the hydraulic actuator, and a load detection proportional valve, a valve core displacement sensor, an I pressure sensor, an II pressure sensor, an III pressure sensor and a global controller are further added;
the oil inlet of the load detection proportional valve is connected with a main oil way PL；
The valve core displacement sensor is characterized in that a through shaft is arranged on a valve core of the load detection proportional valve and directly detects the position and the speed of the valve core of the load detection proportional valve; or the proportional electromagnet is integrated on the proportional electromagnet, and the displacement and the speed of the valve core of the load detection proportional valve are detected by detecting the position of the iron core of the proportional electromagnet;
the pressure sensor and the main oil passage PLThe communication is used for detecting the outlet pressure of the main hydraulic pump; the second pressure sensor and the third pressure sensor are respectively communicated with the two cavities of the hydraulic actuator to detect the pressure of the two cavities of the hydraulic actuator;
the output signals of the first pressure sensor, the second pressure sensor and the third pressure sensor and the output signal of the load detection proportional valve spool displacement sensor are connected to the input end of the global controller;
the signal output end of the global controller is connected with the proportional electromagnet of the load detection proportional valve and the swing angle control end of the main hydraulic pump;
and the signal output end of the global controller is connected with the rotating speed control end of the power source.
A shuttle valve group is further added, the maximum load pressure of a plurality of hydraulic actuators is screened and detected through a plurality of shuttle valves, the oil outlet of the shuttle valve group is connected to the spring cavity of the valve core of the load detection proportional valve through a hydraulic pipeline, and the other cavity of the valve core of the load detection proportional valve is connected with the main oil way P through the hydraulic pipelineLAnd the communication is used for detecting the outlet pressure of the main hydraulic pump.
A hydraulic accumulator is further added, and the load detection proportional valve is one of a two-position two-way valve and a three-position three-way valve; when the load detection proportional valve is a three-position three-way valve, an oil outlet E of the load detection proportional valve is communicated with an oil tank, and the other oil outlet F of the load detection proportional valve is communicated with a hydraulic accumulator; when the load detection proportional valve is a two-position two-way valve, the oil outlet of the load detection proportional valve is communicated with the oil tank.
A bypass oil supplementing unit is further added; when the load detection proportional valve is a two-position two-way valve or is not provided with the load detection proportional valve, one end of an oil port of the bypass oil supplementing unit is connected with the hydraulic accumulator, and the other end of the oil port of the bypass oil supplementing unit is connected with the main oil way PLCommunicating; when the load detection proportional valve is a three-position three-way valve, the bypass oil supplementing unit is connected with the load detection proportional valve in series and additionally arranged between the oil outlet F of the load detection proportional valve and the energy accumulator, the oil inlet of the bypass oil supplementing unit is communicated with the oil outlet of the energy accumulator, and the oil outlet of the bypass oil supplementing unit is communicated with the oil outlet F of the load detection proportional valve.
The bypass oil supplementing unit comprises a bypass oil supplementing pump and an oil supplementing power source, and the oil supplementing power source coaxially drives the bypass oil supplementing pump; the bypass oil replenishing pump is one of a fixed displacement pump or a proportional variable displacement pump; the oil supplementing power source is one of an electric motor or an internal combustion engine; the control end of the bypass oil supplementing pump or oil supplementing power source and the full oil supplementing pumpThe output end of the local controller is connected with the oil suction end of the energy accumulator to the main oil way PLFor oil supply, or from main oil path PLAnd discharging oil to the hydraulic accumulator.
The global controller controls the output flow of the main hydraulic pump according to the difference between the output pressure of the main hydraulic pump and the maximum load pressure of each actuator; the global controller receives a deviation between a valve core displacement signal and a valve core displacement set value of the load detection proportional valve, generates a control signal and controls the flow rate pair of the main hydraulic pump; and the global controller controls the opening of the load detection proportional valve port or the detection pressure difference according to the input signal.
The main control valve is a closed center multi-way reversing valve with a pressure compensator; or an open center multi-way reversing valve with a middle oil way; or an independent control valve set for the oil inlet and the oil outlet.
The power source is one of a diesel engine and an electric motor.
A flow regeneration control valve is further added; an oil inlet of the flow regeneration control valve is communicated with the driving cavity of the hydraulic actuator, and an oil outlet of the flow regeneration control valve is communicated with an oil inlet of the main hydraulic pump.
A flow matching control method is characterized in that: the method comprises the following steps:
the method comprises the following steps: inputting the demand flow signal Q of each main control valve1、Q2、Q3、Q4......QdThe total flow Q of the system is calculated by summing the required flows of all the main control valves to the global controller∑＝Q1+Q2+Q3+Q4……+QdD is a natural number;
step two: comparing the total demand flow Q of the system∑The maximum flow Q which can be output by the current main hydraulic pumpmax(ii) a If the total required flow Q of the system∑Less than the maximum output Q of the main hydraulic pumpmaxThe demand flow signal Q of each main control valve1、Q2、Q3、Q4......QdDirectly inputting the corresponding main control valve;
if the total required flow Q sigma of the system is more than or equal to that of the main hydraulic pumpMaximum flow Q of outputmaxThe demand flow rate signal Q of each main control valve1、Q2、Q3、Q4......QdMultiplied by a gain factor
Then inputting the corresponding main control valve;
step three: the flow signal input by the step two is V according to the formula QpN calculating the displacement of the main hydraulic pump, outputting the total required flow of the system, wherein VpThe displacement of the main hydraulic pump is adopted, and n is the rotating speed of the main hydraulic pump; simultaneously controlling the opening of each main control valve port to enable the valve port with the highest load to independently control the electrohydraulic valve to have the largest opening, and accurately controlling the output flow of each valve port to meet the demand flow signal Q input in the step one by a flow control method1、Q2、Q3、Q4......Qd；
Step four: comparing the output pressure of the main hydraulic pump with the maximum working pressure of each actuator of the system in real time, and controlling the opening degree of a valve port of the load detection proportional valve through the pressure difference of the output pressure of the main hydraulic pump and the maximum working pressure of each actuator of the system; if the displacement of the valve core of the load detection proportional valve is smaller than the theoretical set value, the output flow of the hydraulic pump is smaller than the sum Q of the demanded flows of all the main control valves∑When the system is in a flow under-matching state, the displacement of the main hydraulic pump or the rotating speed of a power source, and the displacement and the rotating speed of the bypass oil replenishing pump are increased; if the displacement of the valve core of the load detection proportional valve is larger than the theoretical set value, the output flow of the hydraulic pump is larger than the sum of the demanded flows of all the main control valves, the system is in a flow over-matching state, the displacement of the main hydraulic pump or the rotating speed of the power source is reduced, the displacement of the valve core of the load detection proportional valve is repeatedly adjusted in such a way, the displacement of the valve core of the load detection proportional valve is equal to the theoretical set value, the output flow of the hydraulic pump is equal to the sum of the demanded flows of all the main control valves, and the output flow of the main hydraulic pump of the system is accurately matched with the demanded flows of all the main control valves.
Compared with the prior art, the invention has the following beneficial effects:
1. the load detection proportional valve is additionally arranged in the system, the pressure difference between the main hydraulic pump and the highest load is sensed in real time through a hydraulic cylinder pipeline or a pressure sensor, the load detection proportional valve is controlled to be communicated with the oil tank or the energy accumulator, the flow state of the system is compensated in time, the problems of pressure impact and energy loss caused by overcurrent matching, poor operability and low control precision caused by undercurrent matching and the like are solved, and the stability and the control precision of the system are improved.
2. The system is additionally provided with a load detection proportional valve integrating a proportional electromagnet and a valve core displacement sensor, the pressure difference between the main hydraulic pump and the highest load is sensed in real time through a hydraulic cylinder pipeline or a pressure sensor, the opening of the load detection proportional valve is controlled, and the output flow of the main hydraulic pump is adjusted by taking the opening as a detection quantity. Compared with the load sensitivity, the pressure control which is easy to generate vibration is converted into the position control of the swing angle of the main hydraulic pump or the rotating speed control of a power source, and the closed-loop control of the output flow of the pump is converted, so that the system flow matching precision is high, and the oscillation is small.
3. The load detection proportional valve is additionally provided with the proportional electromagnet, the difference value between the outlet pressure of the pump and the highest load is dynamically regulated and controlled by controlling the proportional electromagnet of the load detection proportional valve, the variable differential pressure control function is realized, the requirements of high dynamic and low energy consumption of a system are met, and the load adaptability of the system is improved.
4. The invention introduces the bypass oil supplementing unit with small flow, controls the discharge capacity or the rotating speed of the bypass oil supplementing unit aiming at the under-flow matching working condition, supplements the pressure and the flow of the system in time and solves the problem of low response speed of the main hydraulic pump.
Drawings
FIG. 1 is a schematic diagram of a system according to embodiment 1 of the present invention;
FIG. 2 is a flow chart of a control method of the present invention;
FIG. 3 is a schematic diagram of a system according to embodiment 2 of the present invention;
FIG. 4 is a schematic diagram of the main control valve of the present invention employing an open center multiple-way valve configuration;
FIG. 5 is a schematic diagram of a closed center multi-way valve structure with a pressure compensator adopted by the main control valve of the present invention;
FIG. 6 is a schematic diagram of a system according to embodiment 3 of the present invention;
FIG. 7 is a first structure of the main control valve of the present invention, which is an independent control valve set for the oil inlet and the oil outlet;
FIG. 8 is a second configuration of the main control valve of the present invention, which is an independent control valve set for the oil inlet and outlet ports;
FIG. 9 is a drawing of an operating apparatus according to embodiment 4 of the present invention;
FIG. 10 is a schematic diagram of a system according to embodiment 4 of the present invention;
in the figure: 1-power source, 2-main hydraulic pump, 3-main safety valve, 4-main control valve, 5-hydraulic actuator, 6-load detection proportional valve, 7-spool displacement sensor, 8-bypass oil supplementing pump, 9-oil supplementing power source, 10-hydraulic accumulator, 11-I pressure sensor, 12-II pressure sensor, 13-III pressure sensor, 14-global controller, 15-bypass oil supplementing unit, 16-shuttle valve, 17-flow regeneration control valve, 18-traveling body, 19-revolving body, 20-movable arm, 21-arm, 22-bucket, P-traveling bodyLMain oil path, TL-return line, 23-open centre multi-way valve, 24-pressure compensator, 25-third three-position three-way proportional valve, 26-second three-position three-way proportional valve, 27-second two-way proportional valve, 28-second two-way proportional valve, 29-third two-way proportional valve, 30-fourth two-way proportional valve, 31-close centre multi-way valve, 32-pressure compensator, 33-main change valve, L-middle oil line.
Detailed Description
The first embodiment is as follows:
as shown in figure 1, the electro-hydraulic multi-actuator flow control system comprises a power source 1, a main hydraulic pump 2, a main safety valve 3 and a main oil path PLOil return path TLA main control valve 4, a hydraulic actuator 5 and a power source 1 coaxially drive a main hydraulic pump 2, and an oil outlet and a main oil path P of the main hydraulic pump 2LThe oil inlet of the main safety valve 3 is communicated, the oil outlet of the main safety valve 3 is communicated with the oil tank, and the oil inlet and the oil outlet of the main control valve 4 are respectively communicated with the main oil way PLOil return path TLThe working oil way of the main control valve 4 is respectively communicated with two cavities of the hydraulic actuator 5;
the system is also provided with a load detection proportional valve 6, a hydraulic accumulator 10, a first pressure sensor 11, a second pressure sensor 12, a third pressure sensor 13, a global controller 14, a bypass oil supplementing unit 15 and a shuttle valve group 16;
the load detection proportional valve 6 is a two-position two-way valve, a valve core displacement sensor 7 is additionally arranged, and an oil inlet and a main oil way P of the load detection proportional valve 6LThe oil outlet of the load detection proportional valve 6 is communicated with the oil tank; the load detection proportional valve 6 screens and detects the maximum load pressure of a plurality of hydraulic actuators through a shuttle valve group 16, the oil outlet of the shuttle valve group 16 is connected to a spring cavity of a valve core of the load detection proportional valve 6 through a hydraulic pipeline, and the other cavity of the valve core of the load detection proportional valve 6 is connected with a main oil way P through the hydraulic pipelineLThe communication is used for detecting the outlet pressure of the main hydraulic pump 2;
the bypass oil supplementing unit 15 comprises a bypass oil supplementing pump 8 and an oil supplementing power source 9, the bypass oil supplementing pump 8 is a variable pump, and the oil supplementing power source 9 coaxially drives the bypass oil supplementing pump 8 to absorb oil from the hydraulic accumulator 10 to the main oil way PLOil supply; the control end of the bypass oil replenishing pump 8 is connected with the input end of the global controller 14;
the bypass oil supplementing unit 15 is connected with the load detection proportional valve 6 in parallel, the oil inlet of the load detection proportional valve 6 is connected with the hydraulic energy accumulator 10, and the oil outlet of the load detection proportional valve 6 is connected with the main oil way PLCommunicating;
the signal output end of the global controller 14 is connected with a proportional electromagnet of a load detection proportional valve and a swing angle control end of the main hydraulic pump;
the signal output end of the global controller 14 is connected with the swing angle control end of the bypass oil replenishing pump.
When the difference between the outlet pressure of the main hydraulic pump 1 and the maximum load pressure is larger than a set value, the system is in a flow over-matching state, the valve port of the load detection proportional valve 6 is opened under the action of oil control at two ends of the load detection proportional valve 6, and redundant flow of the system flows back to an oil tank through the load detection proportional valve 6; when the difference between the outlet pressure and the maximum load pressure of the main hydraulic pump 1 is smaller than a set value, the system is in a flow rate under-matching state, and the global controller 14 controls the bypass oil supplementing unit 6 to supply oil to the main oil way PLOil supplement, the response speed of the main hydraulic pump 2 is compensated, and the hydraulic accumulator 11 supplements oilThe problem of insufficient pressure.
Fig. 2 shows the overall flow control method of the system. When the system works, the power source 1 is started to drive the main hydraulic pump 2 to operate, and a demand flow signal Q of each main control valve 4 is formed according to an execution instruction of each hydraulic actuator1、Q2、Q3、Q4.., summing the demand flows of all the main control valves 4, and calculating the total demand flow Q of the system∑＝Q1+Q2+Q3+Q4...; comparing the total demand flow Q of the system∑And the maximum flow Q capable of being output by the main hydraulic pumpmax；
If Q∑Less than QmaxThe required flow signal of each main control valve 4 is not changed, and Q is set∑Substituting formula Q ═ Vpn calculating the displacement of the main hydraulic pump 2 and outputting the total required flow of the system, wherein V ispThe displacement of the main hydraulic pump 2 is adopted, n is the rotating speed of the main hydraulic pump, and since the main hydraulic pump is matched with a fixed-speed motor, n is a fixed value;
if Q∑Greater than QmaxMultiplying the flow signal required by each main control valve 4 by a gain coefficient beta and inputting the signal into the corresponding main control valve to obtain QmaxSubstituting formula Q ═ VpN, calculating the displacement of the main hydraulic pump 2 and outputting the total required flow of the system;
the output pressure of the main hydraulic pump 2 is compared with the maximum working pressure of each actuator of the system in real time, and the opening degree of a valve port of the load detection proportional valve 6 is controlled through the pressure difference of the two; if the displacement of the valve core of the load detection proportional valve 6 is smaller than the theoretical set value, the output flow of the main hydraulic pump 2 is smaller than the sum Q of the flow demanded by all the main control valves 4∑When the system is in a flow under-matching state, the displacement of the main hydraulic pump 2 or the rotating speed of the power source 1 is increased, and the displacement and the rotating speed of the bypass oil replenishing pump 8 are increased; if the displacement of the valve core of the load detection proportional valve 6 is larger than the theoretical set value, the output flow of the main hydraulic pump 2 is larger than the sum of the flow demanded by all the main control valves 4, the system is in a flow over-matching state, the load detection proportional valve 6 is opened, the redundant flow of the system flows back to an oil tank through the load detection proportional valve 6, and simultaneously the displacement of the main hydraulic pump 2 or the rotating speed of a power source is reduced, the adjustment is repeated in such a way, so that the displacement of the valve core of the load detection proportional valve 6 is equal to the theoretical set valueAt the moment, the output flow of the main hydraulic pump 2 is equal to the sum of the demanded flows of all the main control valves 4, and the output flow of the main hydraulic pump 2 of the system is accurately matched with the demanded flows of all the main control valves 4.
Example two:
as shown in FIG. 3, the electro-hydraulic multi-actuator flow control system comprises a power source 1, a main hydraulic pump 2, a main safety valve 3 and a main oil path PLOil return path TLA main control valve 4, a hydraulic actuator 5 and a power source 1 coaxially drive a main hydraulic pump 2, and an oil outlet and a main oil path P of the main hydraulic pump 2LThe oil inlet of the main safety valve 3 is communicated, the oil outlet of the main safety valve 3 is communicated with the oil tank, and the oil inlet and the oil outlet of the main control valve 4 are respectively communicated with the main oil way PLOil return path TLThe working oil way of the main control valve 4 is respectively communicated with two cavities of the hydraulic actuator 5;
the system is also provided with a load detection proportional valve 6, a first pressure sensor 11, a second pressure sensor 12, a third pressure sensor 13, a global controller 14 and a shuttle valve 16;
i pressure sensor 11 and main oil path PLThe communication is used for detecting the outlet pressure of the main hydraulic pump 1; the II pressure sensor 12 and the III pressure sensor 13 are respectively communicated with two cavities of the hydraulic actuator 5;
the load detection proportional valve 6 is a three-position three-way valve, a valve core displacement sensor 7 is additionally arranged, and an oil inlet of the load detection proportional valve 6 is connected with a main oil way PLAn oil outlet E of the load detection proportional valve 6 is communicated with an oil tank, and the other oil outlet F is communicated with a hydraulic accumulator 10;
the two ends of the load detection proportional valve 6 are provided with detection oil ports, the spring end of the load detection proportional valve 6 is connected with the oil outlet of the shuttle valve group 16 through a hydraulic oil path, the shuttle valve group 16 screens and detects the maximum load pressure of the plurality of hydraulic actuators 5, and the other end of the load detection proportional valve 6 is connected with the main oil path P through the hydraulic oil pathLThe communication is used for detecting the outlet pressure of the main hydraulic pump 2;
when the difference between the outlet pressure and the maximum load pressure of the main hydraulic pump 1 is larger than a set value, the system is in a flow over-matching state, the load detection proportional valve 6 of the system is in right-position operation under the action of oil control at two ends of the load detection proportional valve 6, and redundant flow flows back to an oil tank; when the difference between the outlet pressure of the main hydraulic pump 1 and the maximum load pressure is smaller than a set value, the system is in a flow rate under-matching state, the load detection proportional valve 6 works in a left position, and the insufficient flow rate is supplemented by the hydraulic accumulator 10.
The input end of a global controller 14 is connected with a II pressure sensor 12, a III pressure sensor 13, a load detection proportional valve 6 valve core displacement sensor 7 and an initial signal input port of two cavities of each hydraulic actuator 5 of an I pressure sensor 11, and the signal output end of the global controller 14 is connected with a proportional electromagnet for controlling the load detection proportional valve 6 and the control end of the main hydraulic pump 2.
A signal output end of the global controller 14 is connected with a proportional electromagnet of a load detection proportional valve and a swing angle control end of the main hydraulic pump;
the signal output end of the global controller 14 is connected with the rotating speed control end of the power source.
As shown in FIG. 4, the main control valve 4 is an open center multi-way valve 23 with a middle oil path, an oil inlet P and a main oil path PLIs communicated with an oil outlet T and an oil return path TLAnd the working oil port A, B is respectively communicated with two cavities of the hydraulic actuator 5. Wherein, a middle position oil inlet F of the opening center multi-way valve 23 of the head-connected main control valve 4-1 is communicated with an oil inlet P, a middle position oil outlet C is communicated with a middle position oil inlet F of the next connecting center multi-way valve 23 through a middle position oil path L, and an oil port C of the opening center multi-way valve 23 of the tail-connected main control valve 4-3 is communicated with an oil tank.
As shown in fig. 5, the main control valve 4 is a closed center multi-way valve 31 with a pressure compensator, and includes a pressure compensator 32 and a main directional control valve 33, wherein an oil inlet of the pressure compensator 32 and a main oil path PLThe oil outlet of the pressure compensator 32 is communicated with the oil inlet P of the main reversing valve 33, the spring end of the pressure compensator 32 is communicated with the oil inlet P of the main reversing valve 33, the other end of the pressure compensator 32 is communicated with the oil inlet of the main reversing valve 33, the oil outlet T of the main reversing valve 33 is communicated with the oil return path TLAnd the working oil port A, B of the main reversing valve is respectively communicated with two cavities of the hydraulic actuator 5.
Example three:
as shown in FIG. 6, an electro-hydraulic multi-actuator flow control system includesPower source 1, main hydraulic pump 2, main safety valve 3, main oil circuit PLOil return path TLA main control valve 4, a hydraulic actuator 5 and a power source 1 coaxially drive a main hydraulic pump 2, and an oil outlet and a main oil path P of the main hydraulic pump 2LThe oil inlet of the main safety valve 3 is communicated, the oil outlet of the main safety valve 3 is communicated with the oil tank, and the oil inlet and the oil outlet of the main control valve 4 are respectively communicated with the main oil way PLOil return path TLThe working oil way of the main control valve 4 is respectively communicated with two cavities of the hydraulic actuator 5;
the system is also provided with a load detection proportional valve 6, a hydraulic accumulator 10, a first pressure sensor 11, a second pressure sensor 12, a third pressure sensor 13, a global controller 14 and a bypass oil supplementing unit 15;
the difference between the embodiment and the embodiment shown in fig. 1 is that the shuttle valve group 16 is not arranged in the system, the global controller 14 calculates the maximum load pressure difference between the main hydraulic pump 2 and each hydraulic actuator 5 through the first pressure sensor 11, the second pressure sensor 12 and the third pressure sensor 13, and controls the opening of the load detection proportional valve 6;
the bypass oil supplementing unit 15 is connected with the load detection proportional valve 6 in series, an oil inlet of the bypass oil supplementing unit 15 is connected with the hydraulic energy accumulator 10, and an oil outlet of the bypass oil supplementing unit 15 is connected with an oil outlet F of the load detection proportional valve 6; the bypass oil supplementing unit 15 comprises a bypass oil supplementing pump 8 and an oil supplementing power source 9, the bypass oil supplementing pump 8 is a fixed displacement pump, and the oil supplementing power source 9 coaxially drives the bypass oil supplementing pump 8 to suck oil from the hydraulic accumulator 10 to the main oil way PLThe control end of an oil supply and supplement power source 9 is connected with the input end of a global controller 14;
the signal output end of the global controller 14 is connected with a proportional electromagnet of a load detection proportional valve and a swing angle control end of the main hydraulic pump;
the signal output end of the global controller 14 is connected with the rotating speed control end of the oil supplementing power source.
When the difference between the outlet pressure of the main hydraulic pump 1 and the maximum load pressure is larger than a set value, the system is in a flow over-matching state, the load detection proportional valve 6 works at the right position, and redundant flow flows back to the oil tank; when the difference between the outlet pressure and the maximum load pressure of the main hydraulic pump 2 is less than a set value, the system isIn the flow rate under-matching state, the load detection proportional valve 6 works at the left position, and the global controller 14 controls the bypass oil supplementing unit 6 to supply oil to the main oil way PLAnd oil is supplemented, so that the problems that the response speed of the main hydraulic pump 2 is low and the oil supplementing pressure of the hydraulic accumulator 10 is insufficient are solved.
As shown in fig. 7, the main control valves 4-1, 4-2 and 4-3 are independent control valve groups of oil inlets, and are composed of a first three-position three-way proportional valve 26 and a second three-position three-way proportional valve 27; oil inlet C of third three-position three-way reversing valve 26ⅠAnd an oil inlet C of a II third-position three-way reversing valve 27ⅡAnd respectively with the main oil path PLCommunicated oil outlet D of the third three-position three-way reversing valve 26ⅠAnd oil outlet D of third three-position three-way reversing valve 27ⅡRespectively connected with an oil return path TLWorking oil port A of communicated three-position three-way reversing valve 26ⅠAnd a working oil port A of a third three-position three-way reversing valve 27ⅡRespectively communicated with two cavities of the hydraulic actuator 5.
FIG. 8 shows a second control valve set structure of the main control valves 4-1, 4-2, and 4-3, which is composed of a first two-way proportional valve 27, a second two-way proportional valve 28, a third two-way proportional valve 29, and a fourth two-way proportional valve 30; oil outlet A of 27 of the second two-way proportional valveⅠOil outlet A of fourth two-way proportional valve 30ⅣRespectively connected with an oil return path TLCommunicated with the oil inlet C of a second two-way proportional valve 28ⅡOil inlet C of 29 second-way proportional valve IIIⅢAre respectively connected with the main oil way PLCommunicated with the oil inlet C of the second two-way proportional valve 27ⅠOil outlet A of second two-way proportional valve 28ⅡRespectively communicated with a cavity of the hydraulic actuator 5 and an oil outlet A of a second two-way proportional valve 29ⅢOil inlet C of fourth two-way proportional valve 30ⅣRespectively communicated with the other cavity of the hydraulic actuator.
Example four:
as shown in fig. 9, a work implement of a hydraulic excavator, which is the most widely used construction machine, mainly includes a traveling structure 18, a revolving structure 19 disposed on the traveling structure 18, a boom 20 connected to the revolving structure 19 and revolving in the vertical direction, an arm 21 attached to a front end of the boom 20, and a bucket 22 attached to a front end of the arm 21.
FIG. 10 is a schematic diagram of the hydraulic system of the excavator, including a power source 1, a main hydraulic pump 2-2, a main safety valve 3-1, a main safety valve 3-2, and a main oil path PL1Main oil passage PL2Oil return path TL4-1, 4-2, 4-3, 4-4, 4-5 and 4-6 of a main control valve, 5-1, 5-2, 5-3, 5-4, 5-5 and 5-6 of a hydraulic actuator.
The power source 1 coaxially drives a main hydraulic pump 2-1 and a main hydraulic pump 2-2, and an oil outlet and a main oil path P of the main hydraulic pump 2-1L1The oil inlet of the main safety valve 3-1 is communicated, the oil outlet of the main safety valve 3-1 is communicated with the oil tank, and the oil outlet of the main hydraulic pump 2-2 is communicated with the main oil way PL2The oil inlet of the main safety valve 3-2 is communicated, and the oil outlet of the main safety valve 3-2 is communicated with the oil tank.
Wherein, the hydraulic actuators 5-1 and 5-2 are hydraulic motors for driving the traveling body 22 to travel left and right, two ends of the hydraulic actuators 5-1 and 5-2 are respectively communicated with working oil ports of the main control valves 4-1 and 4-2, and oil inlets P of the main control valves 4-1 and 4-2L1、PL2Communicated with the oil return ports of the main control valves 4-1 and 4-2 and the oil return path T respectivelyLAnd the main control valves 4-1 and 4-2 adopt a closed center multi-way reversing valve with a pressure compensator.
The main control valve 4-3 is respectively connected with the oil inlet and the oil outlet of the main oil way PL2And an oil return path TLAnd one working oil port of the main control valve 4-3 is communicated with a rodless cavity of the hydraulic actuator 5-3, the other working oil port is communicated with a rodless cavity of the hydraulic actuator 5-5, and the hydraulic actuator 5-5 is a bucket hydraulic cylinder and is used for driving the bucket 22 of the excavator to work. The oil inlet and outlet of the main control valve 4-4 are respectively connected with the main oil way PL2Oil return path TLAnd the main control valve 4-4 is respectively communicated with two ends of a hydraulic actuator 5-3, and the hydraulic actuator 5-3 is a movable arm hydraulic cylinder and is used for driving a movable arm 20 of the excavator to work. The main control valve 4-3 is mainly used for confluence control of the two main hydraulic pumps 2-1 and 2-2, when the main control valve 4-3 works at the left position, the two main hydraulic pumps simultaneously supply oil to the hydraulic actuators 5-3, and when the main control valve 4-3 works at the right position, the two main hydraulic pumps simultaneously supply oil to the hydraulic actuators 5-5. The main control valves 4-3 and 4-4 can adopt inlet and outlet oilThe ports independently control the valve.
In order to recover the gravitational potential energy of the excavator boom 20 in work, a rodless cavity of the hydraulic actuator 5-3 is communicated with an oil inlet of the flow regeneration control valve 17, and an oil outlet of the flow regeneration control valve 17 is communicated with oil inlets of the main hydraulic pumps 2-1 and 2-2. The oil inlet and outlet of the main control valve 4-5 are respectively connected with the main oil way PL1Oil return path TLThe working oil ports of the main control valves 4-5 are respectively communicated with two cavities of the hydraulic actuators 5-4, and the hydraulic actuators 5-4 are rotary motors used for driving the rotary body 19 to move. The main control valves 4-5 can adopt independent control valves of oil inlet and outlet. Oil inlets of main control valves 4-7 and 4-8 are respectively connected with a main oil port PL1、PL2Communication, oil return port and oil return path TLAnd working oil ports of the main control valves 4-7 and 4-8 are respectively communicated with two ends of a hydraulic actuator 5-6, the hydraulic actuator 5-6 is a bucket rod hydraulic cylinder and is used for driving the bucket rod 21 of the excavator to work, and the main control valves 4-8 are used for confluence control of the bucket rod 21. The main control valves 4-7 and 4-8 adopt independent control valves of oil inlet and outlet.
The system is further provided with load detection proportional valves 6-1 and 6-2, global controllers 14-1 and 14-2 and bypass oil supplementing units 15-1 and 15-2; load detection proportional valves 6-1 and 6-2 are three-position three-way valves, valve core displacement sensors 7-1 and 7-2 are additionally arranged, oil inlets of the load detection proportional valves 6-1 and 6-2 are respectively communicated with oil outlets of the main hydraulic pumps 2-1 and 2-2, oil outlets E of the load detection proportional valves 6-1 and 6-2 are communicated with an oil tank, and the other oil outlet F is respectively communicated with hydraulic energy accumulators 10-1 and 10-2 through bypass oil supplementing units 15-1 and 15-2;
the signal output end of the global controller is connected with a proportional electromagnet of a load detection proportional valve and a swing angle control end of the main hydraulic pump; the signal output end of the global controller is connected with the rotating speed control end of the oil supplementing power source.
The two ends of the load detection proportional valves 6-1 and 6-2 are provided with detection oil ports, the spring ends of the load detection proportional valves 6-1 and 6-2 are connected with the oil outlets of the shuttle valve group 16 through hydraulic oil paths, the shuttle valve group 16 screens and detects the maximum load pressure of the hydraulic actuators 5, and the other ends of the load detection proportional valves 6-1 and 6-2 are connected with the main oil path P through the hydraulic oil pathsLConnected for detecting the output of the main hydraulic pumps 2-1 and 2-2A port pressure;
when the difference between the outlet pressure and the maximum load pressure of the main hydraulic pump 1 is larger than a set value, the system is in a flow over-matching state, the load detection proportional valve 6 of the system is in right-position operation under the action of oil ports at two ends of the load detection proportional valves 6-1 and 6-2, and redundant flow flows back to an oil tank; when the difference between the outlet pressure and the maximum load pressure of the main hydraulic pump 1 is smaller than a set value, the system is in a flow rate under-matched state, the load detection proportional valve 6 works in a left position, and the insufficient flow rate is provided by the bypass oil supplementing units 15-1 and 15-2.
Claims (10)
1. An electro-hydraulic multi-actuator flow control system comprises a power source (1), a main hydraulic pump (2), a main safety valve (3) and a main oil way PLOil return path TLThe hydraulic system comprises a main control valve (4) and a hydraulic actuator (5), wherein the power source coaxially drives a main hydraulic pump, and an oil outlet and a main oil path P of the main hydraulic pumpLThe oil inlet of the main safety valve is communicated, the oil outlet of the main safety valve is communicated with the oil tank, and the oil inlet and the oil outlet of the main control valve are respectively communicated with the main oil way PLOil return path TLThe intercommunication, main control valve working oil circuit communicates with two chambeies of hydraulic actuator respectively, its characterized in that:
a load detection proportional valve, a valve core displacement sensor (7), an I pressure sensor (11), an II pressure sensor (12), an III pressure sensor (13) and a global controller (14) are further added;
the oil inlet of the load detection proportional valve is connected with a main oil way PL；
The valve core displacement sensor is characterized in that a through shaft is arranged on a valve core of the load detection proportional valve and directly detects the position and the speed of the valve core of the load detection proportional valve; or the proportional electromagnet is integrated on the proportional electromagnet, and the displacement and the speed of the valve core of the load detection proportional valve are detected by detecting the position of the iron core of the proportional electromagnet;
the No. I pressure sensor and the main oil path PLThe communication is used for detecting the outlet pressure of the main hydraulic pump; the II pressure sensor and the III pressure sensor are respectively communicated with the two cavities of the hydraulic actuator to detect the pressure of the two cavities of the hydraulic actuator;
the output signals of the I pressure sensor, the II pressure sensor and the III pressure sensor and the output signal of the load detection proportional valve spool displacement sensor are connected to the input end of the global controller;
and the signal output end of the global controller is connected with the proportional electromagnet of the load detection proportional valve and the swing angle control end of the main hydraulic pump.
2. The electro-hydraulic multi-actuator flow control system of claim 1, wherein: a shuttle valve group (16) is further added, the maximum load pressure of a plurality of hydraulic actuators is screened and detected through a plurality of shuttle valves, the oil outlet of the shuttle valve group is connected to the spring cavity of the valve core of the load detection proportional valve through a hydraulic pipeline, and the other cavity of the valve core of the load detection proportional valve is connected with the main oil way P through a hydraulic pipelineLAnd the communication is used for detecting the outlet pressure of the main hydraulic pump.
3. An electro-hydraulic multi-actuator flow control system according to claim 1 or 2, characterized in that: a hydraulic energy accumulator (10) is further additionally arranged, and the load detection proportional valve is one of a two-position two-way valve and a three-position three-way valve; when the load detection proportional valve is a three-position three-way valve, an oil outlet E of the load detection proportional valve is communicated with an oil tank, and the other oil outlet F of the load detection proportional valve is communicated with a hydraulic energy accumulator; when the load detection proportional valve is a two-position two-way valve, the oil outlet of the load detection proportional valve is communicated with the oil tank.
4. An electro-hydraulic multi-actuator flow control system according to claim 1, 2 or 3, wherein: a bypass oil supplementing unit (15) is further added;
when the load detection proportional valve is a two-position two-way valve or the load detection proportional valve is not arranged, one end of an oil port of the bypass oil supplementing unit is connected with the hydraulic accumulator, and the other end of the oil port of the bypass oil supplementing unit is connected with the main oil way PLCommunicating;
when the load detection proportional valve is a three-position three-way valve, the bypass oil supplementing unit is connected with the load detection proportional valve in series and additionally arranged between the oil outlet F of the load detection proportional valve and the energy accumulator, the oil inlet of the bypass oil supplementing unit is communicated with the oil outlet of the energy accumulator, and the oil outlet of the bypass oil supplementing unit is communicated with the oil outlet F of the load detection proportional valve.
5. The electro-hydraulic multi-actuator flow control system of claim 4, wherein:
the bypass oil supplementing unit comprises a bypass oil supplementing pump (8) and an oil supplementing power source (9), and the oil supplementing power source coaxially drives the bypass oil supplementing pump;
the bypass oil replenishing pump is one of a fixed displacement pump or a proportional variable displacement pump;
the oil supplementing power source is one of an electric motor or an internal combustion engine;
the control end of the bypass oil supplementing pump or the oil supplementing power source is connected with the output end of the global controller, and the oil is absorbed from the hydraulic accumulator to the main oil way PLFor oil supply, or from main oil path PLAnd discharging oil to the hydraulic accumulator.
6. An electro-hydraulic multi-actuator volume control system according to claim 1 or 5, characterized in that: the global controller controls the rotation speed or the displacement of the bypass oil replenishing pump according to the difference between the output pressure of the main hydraulic pump and the maximum load pressure of each actuator;
the global controller receives the deviation between the valve core displacement signal of the load detection proportional valve and a valve core displacement set value, generates a control signal and controls the output flow of the main hydraulic pump;
and the global controller controls the opening of the load detection proportional valve port or the detection pressure difference according to the input signal.
7. The electro-hydraulic multi-actuator flow control system of claim 1, wherein: the main control valve is a closed center multi-way reversing valve with a pressure compensator; or an open center multi-way reversing valve with a middle oil way; or an independent control valve set for the oil inlet and the oil outlet.
8. The electro-hydraulic multi-actuator flow control system of claim 1, wherein: the power source is one of a diesel engine and an electric motor.
9. The electro-hydraulic multi-actuator flow control system of claim 1, wherein: a flow regeneration control valve (17) is further added; an oil inlet of the flow regeneration control valve is communicated with the driving cavity of the hydraulic actuator, and an oil outlet of the flow regeneration control valve is communicated with an oil inlet of the main hydraulic pump.
10. An electro-hydraulic multi-actuator flow control method applying the system of claim 1, which is characterized in that: the method comprises the following steps:
the method comprises the following steps: inputting the demand flow signal Q of each main control valve1、Q2、Q3、Q4......QdTo the global controller, summing the demanded flows of all the main control valves and calculating the total demanded flow Q of the system∑＝Q1+Q2+Q3+Q4……+QdD is a natural number;
step two: comparing the total demand flow Q of the system∑The maximum flow Q which can be output by the current main hydraulic pumpmax(ii) a If the total required flow Q of the system∑Less than the maximum output Q of the main hydraulic pumpmaxThe demand flow signal Q of each main control valve1、Q2、Q3、Q4......QdDirectly inputting the corresponding main control valve;
if the total required flow Q of the system∑Greater than or equal to the maximum flow Q capable of being output by the main hydraulic pumpmaxThe demand flow signal Q of each main control valve1、Q2、Q3、Q4......QdMultiplied by a gain factor
Then inputting the corresponding main control valve;
step three: the flow signal input by the step two is V according to the formula QpN calculating the main hydraulic pressurePump displacement, total demand flow of output system, V in formulapThe displacement of the main hydraulic pump is adopted, and n is the rotating speed of the main hydraulic pump; simultaneously controlling the opening of each main control valve port to enable the valve port with the highest load to independently control the electrohydraulic valve to have the largest opening, and accurately controlling the output flow of each valve port to meet the demand flow signal Q input in the step one by a flow control method1、Q2、Q3、Q4......Qd；
Step four: comparing the output pressure of the main hydraulic pump with the maximum working pressure of each actuator of the system in real time, and controlling the opening degree of a valve port of the load detection proportional valve through the pressure difference of the output pressure of the main hydraulic pump and the maximum working pressure of each actuator of the system; if the displacement of the valve core of the load detection proportional valve is smaller than the theoretical set value, the output flow of the hydraulic pump is smaller than the sum Q of the demanded flows of all the main control valves∑When the system is in a flow under-matching state, the displacement of the main hydraulic pump or the rotating speed of a power source, and the displacement and the rotating speed of the bypass oil replenishing pump are increased; if the displacement of the valve core of the load detection proportional valve is larger than the theoretical set value, the output flow of the hydraulic pump is larger than the sum of the demanded flows of all the main control valves, the system is in a flow over-matching state, the displacement of the main hydraulic pump or the rotating speed of a power source is reduced, the displacement of the load detection proportional valve core is repeatedly adjusted to be equal to the theoretical set value, the output flow of the hydraulic pump is equal to the sum of the demanded flows of all the main control valves, and the output flow of the main hydraulic pump of the system is accurately matched with the demanded flows of all the main control valves.
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| CN115030938A (en) * | 2022-06-30 | 2022-09-09 | 三一汽车起重机械有限公司 | Hydraulic heat dissipation oil return system, control method and engineering machinery |
| CN115992841A (en) * | 2022-12-08 | 2023-04-21 | 重庆大学 | Flow self-compensating load-sensitive pump valve coordinated electro-hydraulic system and control method |
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| CN115030938A (en) * | 2022-06-30 | 2022-09-09 | 三一汽车起重机械有限公司 | Hydraulic heat dissipation oil return system, control method and engineering machinery |
| CN115992841A (en) * | 2022-12-08 | 2023-04-21 | 重庆大学 | Flow self-compensating load-sensitive pump valve coordinated electro-hydraulic system and control method |
| WO2024140139A1 (en) * | 2022-12-26 | 2024-07-04 | 长沙亿美博智能科技有限公司 | Digital-hydraulic flow matching system and control method therefor |
| CN116447191A (en) * | 2023-04-10 | 2023-07-18 | 重庆大学 | Active damping compensation vibration suppression method for dual-actuator valve port independent control system |
| CN116447191B (en) * | 2023-04-10 | 2024-01-16 | 重庆大学 | Active damping compensation vibration suppression method for dual-actuator valve port independent control system |
| CN118564274A (en) * | 2024-07-31 | 2024-08-30 | 中煤北京煤矿机械有限责任公司 | Multistage feedback type hydraulic support servo control system |
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