CN117720007A - A power distribution control system and method applied to hydraulic systems - Google Patents
A power distribution control system and method applied to hydraulic systems Download PDFInfo
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- CN117720007A CN117720007A CN202311544884.2A CN202311544884A CN117720007A CN 117720007 A CN117720007 A CN 117720007A CN 202311544884 A CN202311544884 A CN 202311544884A CN 117720007 A CN117720007 A CN 117720007A
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Abstract
The invention discloses a power distribution control system applied to a hydraulic system, which comprises a controller, a pressure sensor, a displacement sensor, a rotation speed sensor, a handle, a proportional electromagnetic valve and an executing mechanism, wherein the controller is used for controlling the displacement sensor to rotate at a constant speed; the controller is used for collecting and processing signals and relevant operation processing and sending out control instructions; the pressure sensor is used for measuring the outlet pressure of the oil pump and determining the load condition; the displacement sensor is used for detecting the displacement of the variable servo oil cylinder of the oil pump so as to determine the actual displacement of the oil pump; the rotating speed sensor is used for measuring the rotating speed of the motor, determining the running speed and feeding back to the controller for closed-loop control; the angle signal of the handle swing is transmitted to a controller in a current mode, and the controller controls the current of the proportional electromagnetic valve of the oil pump through logic operation; the proportional solenoid valve controls the oil pump displacement, and the solenoid valve control current and the oil pump displacement are in a linear relationship. The invention can fully utilize the power of the engine and ensure the working efficiency of the system.
Description
Technical Field
The invention belongs to the field of engineering machinery, and particularly relates to a power distribution control system and method applied to a hydraulic system.
Background
With the development of engineering machinery, the performance of the crane is higher, in some hydraulic systems of the crane, each action often has a set of independent systems, such as winch, swing, walking and the like, and each system has an independent pump and an independent executing mechanism, and the systems share a power source and work without interference. When a plurality of independent hydraulic systems need to work cooperatively, the action coordination of each system is needed, and the maximum power output by the engine at a certain rotating speed is constant, so that the power distributed to each system is suitable for the action coordination requirement. In other words, when a plurality of systems cooperate to complete a certain work, the total power required by each system is matched with the maximum power which can be output by the engine under the control mode based on the rotating speed. For example, the running mechanism of the crawler crane takes a set of independent closed hydraulic systems as power, when the crawler crane needs to move forward or turn at a synchronous or certain speed, the movement speeds of the crawler crane at the two sides are required to output corresponding speeds according to the swing angle of the swing handle of the operator in a linear manner, the angle change range of the operating handle at the two sides is identical to the speed change range of the crawler crane at the two sides, and thus, the crawler crane has good operation experience. According to the external characteristic curve of the engine for the engineering machinery, as shown in fig. 1, the maximum power which can be provided by the engine at different rotating speeds is different, the engine works in a rotating speed-based control mode, if the operating handle of the control system is from 0 degrees to the maximum angle, the displacement of the corresponding oil pump is from 0 to the maximum displacement, when the loads of the crawler belts on two sides are large, namely, the system pressure is too high, the total power required by the running system exceeds the maximum power which can be provided by the engine at a certain rotating speed, so that the engine is flameout, and when a plurality of independent systems work together, a split power control method is needed to solve the problem of matching between the system and the engine.
In the prior art, the technical scheme of simultaneous cooperation of a plurality of independent systems mainly comprises two types, and the first type is that if the condition that the output power is exceeded when the rotation speed of an engine is relatively low exists, the engine is often controlled to be in a smaller range with a higher rotation speed so as to meet the requirement of the system on high power; the second technical scheme is to limit the acting power of the hydraulic system below a certain specific power and meet the power of the engine at a certain specific lower rotating speed, and the working range of the rotating speed of the engine is from the specific lower rotating speed to the maximum rotating speed. Or an engine with larger power is selected, so that the engine can meet the load requirement at any rotating speed when the system is at full load. These two schemes have the following disadvantages: the engine is always at a high rotating speed in the first scheme, so that the oil consumption is increased, and the speed regulation interval of the system is reduced; the capacity of the hydraulic system and the capacity of the engine of the second scheme are not fully utilized, so that the waste of resources is caused.
Disclosure of Invention
The invention aims to: the invention aims to provide a power distribution control system which has high working efficiency and high operating speed and is applied to a hydraulic system; another object of the present invention is to provide a power distribution control method applied to a hydraulic system.
The technical scheme is as follows: the invention relates to a power distribution control system applied to a hydraulic system, which comprises a controller, a pressure sensor, a displacement sensor, a rotation speed sensor, a handle, a proportional electromagnetic valve and an executing mechanism, wherein the controller is used for controlling the displacement sensor to rotate; the controller is used for collecting and processing signals and relevant operation processing and sending out control instructions; the pressure sensor is used for measuring the outlet pressure of the oil pump and determining the load condition; the displacement sensor is used for detecting the displacement of the variable servo oil cylinder of the oil pump so as to determine the actual displacement of the oil pump; the rotating speed sensor is used for measuring the rotating speed of the motor, determining the running speed and feeding back to the controller for closed-loop control; the angle signal of the handle swing is transmitted to a controller in a current mode, and the controller controls the current of the proportional electromagnetic valve of the oil pump through logic operation; the proportional solenoid valve controls the oil pump displacement, and the solenoid valve control current and the oil pump displacement are in a linear relationship.
The actuating mechanism comprises an oil pump, a motor, an oil supplementing system and a flushing system; the oil pump is used for executing tasks, the oil supplementing system and the flushing system serve the oil pump, and the motor is used for adjusting the opening and closing of the oil pump.
The controller is arranged in the electric cabinet, receives signals of all sensors in the system and sends out control instructions.
The pressure sensors are arranged at two oil ports of the oil pump, and detect the outlet pressure of the oil pump in real time and transmit the outlet pressure to the controller.
The displacement sensor is arranged on the oil pump, detects the displacement of the oil pump and transmits the displacement to the controller.
Wherein the handle is mounted in a control cabin or a remote control box.
Wherein the proportional solenoid valve is installed at an output port of the oil pump.
A power distribution control method applied to a hydraulic system, comprising the steps of:
step 1, a controller receives signals of various sensors and engine rotating speed signals, performs corresponding operation according to control logic, and calculates the maximum total allowable displacement of each system oil pump under the working condition according to the maximum power which can be output by the engine under a certain rotating speed, namely the total power of the hydraulic system acting;
step 2, determining the maximum control current of the oil pump common to each system, wherein the maximum swing angle of the handle corresponds to the control current, and performing linear difference conversion on the control current range of the oil pump and the angle range of the handle;
and 3, in the working process, the actual displacement of the oil pump of each system and the swinging angle of the handle of each system are in a linear relation, if the swinging angles of the control handles of each system are consistent, the ratio of the flow of each system to the maximum flow which can be output by the system is the same, and if the swinging angles of the control handles of each system are inconsistent, the systems are regulated according to the respective handle angle ratio.
Wherein, the oil pump displacement V of each system n And displacement control current I n The relationship between them is as follows:
V n ＝k n I n ；
wherein k is n Controlling current and displacement conversion coefficients for displacement;
the engine works at a certain stable rotation speed, the maximum power W which can be output by the engine is constant, and each hydraulic system carries out constant power adjustment under the power, so that the displacement V of each hydraulic system n And each system load P n The relation is as follows:
Kn(V 1 P 1 +V 2 P 2 ……V n P n )≤W；
wherein K is a displacement pressure torque conversion coefficient, and n is a rotating speed;
Kn(k 1 I 1 P 1 +k 2 I 2 P 2 ……k n I n P n )≤W；
the control current ranges are the same regardless of the size and the small of the pumps of each system, i.e. the minimum value of the control current corresponds to the minimum displacement of the pumps and the maximum value of the control current corresponds to the maximum displacement of the pumps.
The maximum control current of the system is represented by the following relation between I and power load:
KnI(k 1 P 1 +k 2 P 2 ……k n P n ) W is less than or equal to W; due to k 1 P 1 +k 2 P 2 ……k n P n ＝P；
The method further comprises the following steps: ip=w/Kn, where P is the total load of each hydraulic system.
The beneficial effects are that: compared with the prior art, the invention has the following advantages:
(1) The invention provides a constant power distribution control technology of a multi-hydraulic system based on dynamic power matching of an engine, a full-working-condition power distribution model is established, a full-working-condition intelligent detection control module is established, closed-loop feedback control under full power section and full working condition is integrated, the working power of a hydraulic system and an engine power curve are intelligently matched, and the system can adjust the displacement range of each pump according to the maximum power output by the engine in real time and the external load condition of each hydraulic system, so that the system power is adjusted, the system can be matched with the engine, the engine power can be fully utilized, and the working efficiency of the system can be ensured. An optimal control algorithm for multi-system flow distribution is established, and the action coordination of the multi-system is dynamically adjusted, so that the multi-system synchronous and coordinated work under various working conditions is realized. Oil consumption is saved, a wider speed regulation interval is realized, the capacities of the hydraulic system and the engine are fully exerted, and the operation efficiency and the economy are improved. The control idea of the invention reduces the difficulty of engine power selection according to the matching relation between the hydraulic system and the engine when designing the control system.
(2) According to the invention, the speed regulation interval of the hydraulic system is large, when the handle is at a certain angle, the rotating speed of the engine is increased, so that the rotating speed of the system pump is increased, the curve of the angle of the handle and the displacement control current can be steeped, the displacement of the pump is also increased, and the system regulation speed is obviously increased.
Drawings
FIG. 1 is an engine external map;
FIG. 2 is a schematic diagram of a system architecture;
fig. 3 is a graph of swing angle and input current characteristics;
FIG. 4 is a graph of a characteristic of a controller receiving handle current and displacement control current;
FIG. 5 is a graph of handle angle and displacement control current characteristics;
FIG. 6 is a graph of characteristics of oil pump displacement and displacement control current for each system;
FIG. 7 is a graph of total load of hydraulic systems and maximum control current for each hydraulic system oil pump;
fig. 8 is a graph of handle angle versus displacement control current.
Detailed Description
As shown in fig. 2, the invention is applied to a power distribution control system of a hydraulic system, and comprises a controller, a pressure sensor, a displacement sensor, a rotation speed sensor, a handle and a proportional electromagnetic valve. The controller is used for collecting and processing signals and relevant operation processing and sending out control instructions; the pressure sensor is used for measuring the outlet pressure of the oil pump and determining the load condition; the displacement sensor is used for detecting the displacement of the variable servo oil cylinder of the oil pump so as to determine the actual displacement of the oil pump; the rotating speed sensor is used for measuring the rotating speed of the motor, determining the running speed and feeding back to the controller for closed-loop control; the handle is operated by an operator, an angle signal of the swing of the handle is transmitted to the controller in a current mode, the controller identifies the intention of the operator, carries out logic operation and controls the current of the proportional electromagnetic valve of the oil pump; the proportional solenoid valve controls the oil pump displacement, and the solenoid valve control current and the oil pump displacement are in a linear relationship shown in fig. 6; the executing mechanism comprises an oil pump, a motor, an oil supplementing system and a flushing system; the oil pump is used for executing tasks, the oil supplementing system and the flushing system serve the oil pump, and the motor is used for adjusting the opening and closing of the oil pump.
Signal transmission between control system and actuator: the controller is arranged in the electrical cabinet, receives signals of various sensors in the system and sends out control instructions. The pressure sensor is arranged at two oil ports of the oil pump, detects the outlet pressure of the oil pump in real time, and transmits the outlet pressure to the controller. The displacement sensor is arranged on the oil pump, detects the displacement of the oil pump and transmits the displacement to the controller. According to the detected pressure and displacement, the controller can calculate the working power of the hydraulic system. The rotation speed sensor is arranged on the motor and used for detecting the rotation speed of the motor and transmitting the rotation speed to the controller. The handle is arranged in the control room or on the remote control box and transmits the instruction of an operator to the controller. The proportional solenoid valve is installed on the oil pump, signals input by the sensors of the controller are subjected to a series of logic operation to output certain current to the proportional solenoid valve, the proportional solenoid valve controls the variable of the oil pump, and the oil pump outputs certain flow of oil to do work.
The control process comprises the following steps: in the working process, the controller receives signals of the sensors and engine rotating speed signals, performs corresponding operation according to control logic, calculates the maximum total allowable displacement of the oil pumps of all the systems under the working condition according to the maximum power which can be output by the engine at a certain rotating speed, namely the total power of the hydraulic system, determines the maximum control current of the oil pumps which are common to all the systems, and at the moment, the maximum swinging angle of the handle corresponds to the control current, and the linear difference value conversion is performed between the control current range of the oil pump and the angle range of the handle. The control current range of each system pump is the same, and the maximum displacement of the pump at a certain rotating speed of the engine according to the control logic is the same as the maximum displacement ratio of the oil pump. In the working process, the actual displacement of the oil pump of each system and the swinging angle of the handle of each system are in a linear relation, if the swinging angles of the control handles of each system are consistent, the flow of each system is the same as the maximum flow ratio which can be output by the system, and if the swinging angles of the control handles of each system are inconsistent, each system is regulated according to the respective handle angle proportion. In the process, the motor rotating speed feedback signal detected by the rotating speed sensor is used for real-time adjustment, so that the relative value of the working speed of the system is ensured, and the accuracy and coordination of speed control are ensured.
To further explain this control method, the relationship of several physical quantities involved in the control is described as follows:
the handle, the element for the operator to input commands, the swing angle of which is linear with the input current to the handle received by the controller, as shown in fig. 3. After receiving the control current of the handle, the controller outputs current to the proportional solenoid valve to control the displacement of the oil pump, and the relation between the handle current and the displacement control current is shown in fig. 4. In this way, the relationship between the handle angle and the displacement control current can be deduced as shown in fig. 5.
As shown in fig. 6, the oil pump displacement V of each system n And displacement control current I n The relationship between them is as follows:
V n ＝k n I n formula 1;
k n controlling current and displacement conversion coefficients for displacement;
the engine works at a certain stable rotation speed, the maximum power W which can be output is fixed, thus each hydraulic system carries out constant power adjustment under the power, and the displacement V of each hydraulic system n And each system load P n The relation is as follows:
Kn(V 1 P 1 +V 2 P 2 ……V n P n ) W is less than or equal to 2;
wherein K is a displacement pressure torque conversion coefficient, and n is a rotating speed;
from the combination of equations 1 and 2, relationship 3 is obtained for controlling current, pressure and power
Kn(k 1 I 1 P 1 +k 2 I 2 P 2 ……k n I n P n ) W is less than or equal to 3;
the control current range is the same regardless of the size and the magnitude of each system pump, i.e., 200mA corresponds to the minimum displacement of the pump and 600mA corresponds to the maximum displacement of the pump. In order to coordinate the actions of the systems, the handle swing range corresponds to the same displacement control current interval of the systems, and the maximum control current of the systems is represented by the following relation between I and power load:
KnI(k 1 P 1 +k 2 P 2 ……k n P n ) W is less than or equal to 4;
let k 1 P 1 +k 2 P 2 ……k n P n =p formula 5;
wherein P is the total load of each hydraulic system;
the calculation of the combined formula 4 and formula 5 is carried out: ip=w/Kn formula 6.
The graph of the total load of the hydraulic system and the maximum control current of the oil pump of each hydraulic system is shown in fig. 7, and the engine is at a certain stable rotating speed n 1 The engine can supply the external load with power W 1 Referring to FIG. 1, the hydraulic system operates according to the power curve 1 of FIG. 7 with a total load P 1 When the maximum control current of each system is I 1 The relationship of handle angle and displacement control current is performed according to curve 1 of fig. 8; total load P 2 When the maximum control current of each system is I 1 The relationship of handle angle and displacement control current is performed according to curve 2 of fig. 8. At another stable rotation speed, the power which can be provided to the external load by the engine is W 2 Referring to FIG. 1, the hydraulic system operates according to the power curve 2 of FIG. 7, and calculates the maximum displacement based on the loadThe current is controlled.
Claims (10)
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| Application Number | Priority Date | Filing Date | Title |
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| CN202311544884.2A CN117720007A (en) | 2023-11-20 | 2023-11-20 | A power distribution control system and method applied to hydraulic systems |
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| CN202311544884.2A CN117720007A (en) | 2023-11-20 | 2023-11-20 | A power distribution control system and method applied to hydraulic systems |
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN118929461A (en) * | 2024-10-12 | 2024-11-12 | 中联重科股份有限公司 | Method and device for controlling working vehicle and engineering vehicle |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
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| CN118929461A (en) * | 2024-10-12 | 2024-11-12 | 中联重科股份有限公司 | Method and device for controlling working vehicle and engineering vehicle |
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