Multi-actuator variable speed pump valve compound control method for hydraulic control

Abstract

The present application relates to a kind of for hydraulic control multi-actuator variable speed pump valve composite control method, it includes the following steps, step 1: identifying the motion state of variable speed pump valve actuator;Step 2: the selection and coordination of multi-actuator variable speed pump valve control strategy;Step 3: control actuator composite action, realize the composite control of multiple-way valve variable speed pump valve.The present application adopts variable speed pump valve composite control system without presetting pressure margin, improves the stability and dynamic response of composite control system, reduces energy loss;Through the displacement of pressure compensation controller control multiple-way valve spool, realize the pressure compensation function when system load difference, compared with the structure of using traditional pressure compensator, reduce the pressure loss;Adopt the multi-actuator single action and composite action degree control strategy suitable for variable speed pump valve composite control system, by coordinating the speed of pump and the opening of valve, further reduce energy consumption.

Description

Technical Field

[0001] This application relates to the field of hydraulic technology, and specifically to a multi-actuator variable speed pump-valve composite control method for hydraulic control. Background Technology

[0002] Hydraulic transmission systems are characterized by high power-to-weight ratio, large output force, and wide speed range, making them widely used in multi-actuator equipment in fields such as construction, industry, military, aerospace, and earthmoving. Hydraulic control systems for multi-actuator equipment include hydraulic-mechanical load-sensitive systems, electro-hydraulic sensitive control systems, electro-hydraulic flow matching systems, independent inlet / outlet control systems, and electro-hydraulic pump control systems.

[0003] Currently, traditional load-sensitive systems still dominate hydraulic control systems for multi-actuator equipment. These systems mostly employ variable displacement pumps as the power source, with multi-way valves using post-valve or pre-valve pressure compensation to ensure that the flow rate remains constant regardless of load. Simultaneously, shuttle valves detect system pressure and control the load-sensitive valves of the variable pumps. Closed-loop feedback control of pressure is achieved through preset pressure margins, thereby controlling the flow rate supplied by the load-sensitive pumps to the system. Traditional load-sensitive systems, due to their use of mechanically controlled variable pumps and mechanical pressure detection piping networks, coupled with preset pressure margins, result in complex pump variable mechanisms and piping, long control distances, and pressure signal lag, reducing system stability and dynamic response, and leading to low system energy efficiency. Furthermore, the use of pressure compensation valves to balance load differences causes additional pressure losses. Control strategies are often tailored to system characteristics and operational requirements, employing flow / pressure composite control strategies, multi-mode hierarchical control, and pump-valve segmented control, but the universality of these control strategies needs improvement. Summary of the Invention

[0004] To overcome the shortcomings of existing technologies, this invention employs a variable speed pump-valve composite control system that eliminates the need for a preset pressure margin, thereby improving the stability and dynamic response of the composite control system and reducing energy loss. It achieves pressure compensation for system load differences by controlling the displacement of the multi-way valve core through a pressure compensation controller, reducing pressure loss compared to traditional pressure compensators. Furthermore, it adopts a multi-actuator single-action and composite motion control strategy adapted to the variable speed pump-valve composite control system, further reducing energy loss by coordinating the pump speed and valve opening.

[0005] To achieve the above objectives, the solution adopted by the present invention is as follows:

[0006] A multi-actuator variable speed pump-valve composite control method for hydraulic control includes the following steps:

[0007] Step 1: Identify the motion state of the variable speed pump valve actuator;

[0008] Obtain the output signal α1 of the first actuator and the output signal α2 of the second actuator, up to the output signal α of the nth actuator. n When k = f(α) i When k = f(α) = 1, i = 1, 2, ..., n, the motion state recognition result is single-action actuator; when k = f(α) i When k = f(α) ≥ 2, i = 1, 2, ..., n, the motion state recognition result is a compound action of the actuator; when k = f(α) ≥ 2, i = 1, 2, ..., n, the motion state recognition result is a compound action of the actuator. i When (≠0)=0, i=1,2,…,n, the motion state recognition result is standby state;

[0009] Step 2: Selection and coordination of control strategies for multi-actuator variable speed pumps and valves;

[0010] Obtain the motion state recognition results from step 1. The control strategy for single-action actuators is determined to be a single-action control strategy; the control strategy for compound-action actuators is determined to be a compound-action control strategy; no control strategy needs to be activated in the standby state.

[0011] Step 21: The single-action control strategy described above adopts a single-action control strategy in which the valve ports of the multi-way valve are fully open and the pump flow controller controls the speed of the servo motor to realize the movement of the variable speed pump control actuator.

[0012] In single-action mode, the main controller pre-controlles the pump flow controller to output the base flow rate based on the opening signal of the actuator's electric control handle, causing the system to build up pressure. The pressure compensation controller outputs the maximum valve core control signal Xmax to fully open the multi-way valve. The pressure sensor collects the inlet and outlet pressures p1 and p2 of the multi-way valve and the pump outlet pressure p in real time. s1 The calculated differential pressure signal Δp = p1 - p2 from the multi-channel valves is transmitted to the main controller in real time. The main controller then adjusts the signal based on the load pressure p in real time. L The theoretical pump inlet pressure p is calculated using the differential pressure signal Δp from the multi-way valve. sT The output signal is sent to the pump flow controller to drive the fixed displacement pump. The pump inlet pressure is controlled in real time to change the valve inlet pressure difference, so that it satisfies the following formula:

[0013] p s1 =p L +Δp=p L +(p1-p2);

[0014] In the formula: p s1 p represents the pressure at the first pump inlet. L Δp represents the load pressure; p1 represents the differential pressure signal of the multi-way valve; p2 represents the inlet pressure of the first multi-way valve;

[0015] A single-action control strategy for actuator motion is achieved by controlling the flow rate through a variable-speed pump.

[0016] Step 22: The composite motion control strategy adopts a composite motion control strategy that uses a pressure compensation controller to correct the displacement of the multi-way valve core in real time, controls the valve opening of the multi-way valve of the actuator to realize the movement of the valve-controlled multi-actuator, and drives the pump to match the system flow by changing the speed of the pump flow controller.

[0017] When the actuator is in a compound action state, the actuator control handle outputs signals α1, α2, ..., α i The pump flow controller first presets the servo motor speed based on the output signal from the actuator's electric control handle, then controls the servo motor to drive the fixed displacement pump to output the system's basic flow rate. The pressure compensation controller collects the pressure and displacement signals from the multi-way valve through pressure and displacement sensors, and calculates the flow rates Q1, Q2, ..., Q of the multi-way valve in real time. i and pressure difference Δp 11 Δp 22 , …, Δp jj When Q1 + Q2 + ... + Q i smax Q smax When the system's fixed displacement pump reaches its maximum output flow rate, the system is in an unsaturated flow state. At this point, based on the relationship between the multi-way valve's flow rate Q, pressure difference Δp, and valve core displacement X, the valve core displacement parameters of the multi-way valve are corrected online, and valve core displacement control signals X1, X2, ..., X... are output. i This enables valve-controlled movement of multiple actuators, while the main controller adjusts the movement based on the maximum load pressure p. LMAX Real-time pressure difference Δp of multi-way valve 11 Δp 22 , ..., Δp jj Calculate the theoretical pressure p at the pump inlet sT , and the collected pump inlet pressure p s2 This forms a pressure closed loop, with a control signal sent to the pump flow controller to drive a fixed displacement pump to provide the required flow rate of the system, satisfying the following equation:

[0018] p s2 =p L1 +Δp 11 =p L2 +Δp 22 =…=p Lk +Δp jj ;

[0019] In the formula: p s2 Indicates the pressure at the second pump inlet; p L1 Indicates the real-time load pressure of the first actuator; Δp 11 This indicates the real-time differential pressure of the first multi-way valve; p L2 Indicates the real-time load pressure of the second actuator; Δp 22 This indicates the real-time differential pressure of the second multi-way valve; p Lk Δp represents the real-time load pressure of the k-th actuator.​jj The real-time differential pressure of the j-th multi-way valve is represented; k represents the actuator number, k∈(1,i); j represents the multi-way valve number, j∈(1,i);

[0020] By using a pump-valve composite control flow distribution, a composite action control strategy is achieved to match the system flow by driving the pump with a variable speed of the pump flow controller.

[0021] Step 3: Control the actuator to perform compound actions to achieve compound control of multi-way valve variable speed pump valve;

[0022] When the actuator is in a compound action state, the pressure compensation controller calculates the flow rates Q1, Q2, ..., Q of the multi-way valve in real time. i Satisfying Q1 + Q2 + ... + Q i =Q smax At this time, the system is in a flow saturation state, and the main controller outputs signals α1, α2, ..., α3 to the actuator control handle. i The anti-saturation algorithm is applied to reduce the output signal proportionally, resulting in a new output signal α'. k As shown below:

[0023]

[0024] In the formula: α' k This represents the processed output signal of the k-th actuator control handle; α max The theoretical maximum output Q of the system's fixed displacement pump is represented by... smax The corresponding maximum theoretical output signal of the control handle; This represents the summation of the actual output signals of the control handle; α k This indicates the output signal of the control handle of the k-th actuator; i represents the total number of actuators.

[0025] Then the new output signals α1', α'2, ..., α′ are... i The control handle output signal is replaced in step 22, and the compound motion control strategy is continued to be executed according to step 22 to ensure the coordination of the motion of multiple actuators.

[0026] Preferably, the multi-actuator variable speed pump-valve composite control method described in the above steps specifically includes:

[0027] The main controller collects the opening signal of each actuator's electric control handle, identifies the motion state of each actuator according to step 1, coordinates the control pressure compensation controller and pump flow controller according to step 2 to realize the control strategy of single action or compound action of the actuator, and implements the anti-saturation algorithm processing of the control handle output signal according to step 3.

[0028] Preferably, the pump flow controller in step 2 is used to receive the speed control signal from the main controller and the speed feedback signal from the encoder, forming a closed-loop control of the servo motor speed, and finally controlling the servo motor to drive the quantitative pump to output the required flow rate of the system.

[0029] Preferably, the pressure compensation controller in steps 2 and 3 is used to receive control signals from the main controller, and to collect in real time the inlet and outlet pressures of each actuator's multi-way valve, the pump port pressure, and the valve core displacement signals of each multi-way valve through pressure and displacement sensors. It also calculates the pressure difference and flow rate of each actuator's multi-way valve in real time and transmits this data to the main controller. When the actuator operates alone, it outputs the maximum valve core control signal Xmax to fully open the multi-way valve, thus controlling the pump-driven actuator movement. When the actuator performs compound actions, it corrects the multi-way valve core displacement control signals X1, X2, ..., X... in real time online. i This enables pressure compensation and valve-controlled movement of multiple actuators.

[0030] Preferably, the actuator compound action process in step 3 is as follows:

[0031] When the actuator performs a compound action, the pressure compensation controller stores the relationship between the multi-way valve flow rate Q, the multi-way valve differential pressure signal Δp, and the valve core displacement control signal X, obtained through experiments. This relationship is then controlled by adjusting the differential pressure Δp between the inlet and outlet of the multi-way valve. i The multi-way valve j valve core displacement control signal X j Satisfy the following formula:

[0032]

[0033] In the formula: X j This represents the valve core displacement control signal for the multi-way valve j; Δp j0 Indicates the minimum differential pressure of multi-way valve j; x j This indicates the displacement of the valve core before correction in the multi-way valve J.

[0034] This ensures that the flow rate through the multi-way valve remains unchanged regardless of the load pressure, thereby achieving pressure compensation.

[0035] The second aspect of the present invention proposes a control system for a multi-actuator variable speed pump-valve composite control method for hydraulic control, which can be used in a multi-actuator variable speed pump-valve composite control system. The system consists of an electric control handle, a main controller, a pump flow control unit, a pressure compensation controller unit, and actuators.

[0036] The actuator electric control handle includes a first actuator electric control handle, a second actuator electric control handle, and a third actuator electric control handle, which outputs control signals to the main controller according to the working conditions.

[0037] The main controller enables actuator motion state recognition and the selection and coordination of control strategies.

[0038] The pump flow control unit receives control signals from the main controller and controls the servo motor to drive the metering pump to output pressure and flow. The overflow valve provides overload protection.

[0039] The pressure compensator control unit receives control signals from the main controller and, according to the control strategy, controls the valve core displacement of the first multi-way valve, the second multi-way valve, and the nth multi-way valve, and processes and transmits differential pressure signals.

[0040] The actuator includes a first actuator, a second actuator, and an nth actuator, which are hydraulic cylinders, hydraulic motors, or any combination of both, to convert pressure energy into mechanical energy to perform external work.

[0041] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0042] (1) The present invention adopts a variable speed pump-valve composite control system. Compared with the complex variable mechanism and pressure detection pipeline of the traditional load-sensitive pump, the composite control system does not require a preset pressure margin, which improves the stability and dynamic response of the composite control system and reduces energy loss. The multi-actuator single-action and composite action degree control strategy adapted to the variable speed pump-valve composite control system is adopted. By coordinating the pump speed and valve opening, energy loss is further reduced.

[0043] (2) The present invention uses a pressure compensation controller to control the displacement of the valve core of the multi-way valve to realize the pressure compensation function when the system load is different. Compared with the structure of the traditional pressure compensator, the pressure loss is reduced. Attached Figure Description

[0044] Figure 1 This is a control block diagram of a multi-actuator variable speed pump-valve composite control method for hydraulic control according to an embodiment of the present invention;

[0045] Figure 2 This is a schematic diagram illustrating the actuator motion state recognition and control strategy selection of the present invention.

[0046] Figure 3 This is a schematic diagram of the pressure compensation controller according to an embodiment of the present invention;

[0047] Figure 4 This is a schematic diagram illustrating the principle of the multi-actuator single-action state control strategy of the present invention.

[0048] Figure 5 This is a schematic diagram illustrating the principle of the multi-actuator composite action state control strategy implemented in this invention.

[0049] Figure 6 This is a schematic diagram of the multi-actuator variable speed pump-valve composite control system for implementing the present invention.

[0050] Key reference numerals in the attached drawings: 1. Actuator control handle; 1.1. First actuator control handle; 1.2. Second actuator control handle; 1.n. ​​Nth actuator control handle; 2. Main controller; 3. Pump flow controller unit; 4. Pump flow controller; 5. Encoder; 6. Servo motor; 7. Metering pump; 8. Overflow valve; 9. Pressure compensation controller unit; 10.1. First multi-way valve; 10.2. Second multi-way valve; 11. Actuator; 11.1. First actuator; 11.2. Second actuator; 11.n. Nth actuator; 12. First pressure sensor; 13.1. Second pressure sensor; 13.2. Third pressure sensor; 14.1. Fourth pressure sensor; 14.2. Fifth pressure sensor; 15.1. First displacement sensor; 15.2. Second displacement sensor; 16. Pressure compensation controller. Detailed Implementation

[0051] Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.

[0052] This invention employs a variable-speed pump-valve composite control system. Compared to the complex variable mechanism and pressure detection piping of traditional load-sensitive pumps, the composite control system eliminates the need for preset pressure margins, improving stability and dynamic response while reducing energy loss. A pressure compensation controller controls the valve core displacement of multiple valves to achieve pressure compensation for system load differences, reducing pressure loss compared to traditional pressure compensators. Furthermore, a multi-actuator single-action and composite motion control strategy adapted to the variable-speed pump-valve composite control system further reduces energy loss by coordinating pump speed and valve opening. Figure 1 The diagram shown is a control block diagram of a multi-actuator variable speed pump-valve composite control method for hydraulic control according to an embodiment of the present invention. The main controller 2 collects the opening signals of each actuator's electric control handle 1.1, 1.2, ..., 1.n, and identifies the motion state of each actuator 11.1, 11.2, ..., 11.n according to S1; coordinates the control pressure compensation controller 9 and the pump flow controller 4 according to S2 to implement a control strategy for single or composite actions of actuator 11; and implements an anti-saturation algorithm for the control handle output signal according to S3.

[0053] This invention provides a multi-actuator variable speed pump-valve composite control method for hydraulic control. To demonstrate the applicability of this invention, it is applied to an example, specifically including the following steps:

[0054] S1: Identify the motion state of the variable speed pump valve actuator.

[0055] Obtain the output signal α1 of the first actuator 11.1 and the output signal α2 of the second actuator 11.2, and so on, up to the output signal α of the nth actuator 11.n. n When k = f(α) i When k = f(α) = 1, i = 1, 2, ..., n, the motion state recognition result is actuator 11 acting alone; when k = f(α) i When k = f(α)≥2, i=1, 2, …, n, the motion state recognition result is the composite action of actuator 11; when k=f(α)≥2, i=1, 2, …, n, the motion state recognition result is the composite action of actuator 11. i When (≠0)=0, i=1, 2, …, n, the motion state recognition result is standby state; such as Figure 2 The diagram shown illustrates the actuator motion state recognition and control strategy selection implementation of the present invention.

[0056] S2: Selection and coordination of control strategies for multi-actuator variable speed pumps and valves.

[0057] The motion state recognition results in S1 are obtained. The control strategy for single-action actuator is determined to be a single-action control strategy; the control strategy for compound-action actuator is determined to be a compound-action control strategy; no control strategy needs to be started in the standby state.

[0058] S21: Single-action control strategy, employing a single-action control strategy where the multi-way valve 10.1 is fully open, and the pump flow controller 4 controls the speed of the servo motor 6 to achieve the motion of the variable-speed pump actuator; such as Figure 4 The diagram shown illustrates the principle of the multi-actuator single-action state control strategy implemented in this invention.

[0059] In the single-action state of the actuator, the main controller 2 pre-controlles the pump flow controller 4 to output the base flow rate based on the opening signal of the actuator's electric control handle 1, so that the system can build up pressure. Figure 3 The diagram shown is a schematic of the pressure compensation controller according to an embodiment of the present invention. The pressure compensation controller 16 outputs the maximum valve core control signal Xmax to control the multi-way valve 10.1 to fully open its valve port. Pressure sensors 13.1, 14.1, and 12 collect the inlet and outlet pressures p1 and p2 of the multi-way valve and the pump port pressure p in real time. s1 The differential pressure signal Δp (Δp = p1 - p2) of the multi-way valve 10.1 is calculated and transmitted to the main controller 2 in real time. The main controller 2 then adjusts the signal based on the load pressure p in real time. L The theoretical pump inlet pressure p is calculated using the differential pressure signal Δp from the multi-way valve 10.1. sT The output signal is sent to the pump flow controller 4 to drive the fixed displacement pump 7. The pump inlet pressure is controlled in real time to change the valve inlet pressure difference, so that it satisfies the following formula:

[0060] p s1 =p L +Δp=p L +(p1-p2);

[0061] In the formula: ps1 p represents the pressure at the first pump inlet. L Δp represents the load pressure; Δp represents the differential pressure signal of the multi-way valve; p1 represents the inlet pressure of the first multi-way valve; p2 represents the outlet pressure of the first multi-way valve.

[0062] A single-action control strategy for actuator motion is achieved by controlling the flow rate through a variable-speed pump.

[0063] The pump flow controller 4 is used to receive the speed control signal from the main controller 2 and the speed feedback signal from the encoder 5, forming a closed-loop speed control of the servo motor 6, and finally controlling the servo motor 6 to drive the fixed displacement pump 7 to output the flow required by the system.

[0064] S22: A composite motion control strategy is adopted, which uses a pressure compensation controller 16 to correct the valve core displacement of multi-way valves 10.1 and 10.2 in real time, controls the valve opening of the multi-way valves to achieve valve-controlled multi-actuator movement, and uses a pump flow controller 4 to drive the fixed displacement pump 7 with variable speed to match the system flow rate. Figure 5 The diagram shown illustrates the principle of the multi-actuator composite action state control strategy implemented in this invention.

[0065] When actuator 11 is in a compound action state, the actuator control handle 1 outputs signals α1, α2, ..., α i The pump flow controller 4 first presets the speed of the servo motor 6 based on the output signal of the actuator electric control handle 1, and controls the servo motor 6 to drive the fixed displacement pump 7 to output the system's basic flow. The pressure compensation controller 16 collects the pressure and displacement signals of the multi-way valve through pressure sensors 13.1, 14.1, 13.2, 14.2 and displacement sensors 15.1, 15.2, and calculates the pressure difference Δp of the multi-way valve in real time. 11 , Δp 22 , ..., Δp jj (Δp jj =p j1 -p j2 ) and traffic Q1, Q2, ..., When Q1+Q2+…+Q i smax Q smax At the maximum output flow rate of the system's fixed displacement pump 7, the system is in an unsaturated flow state. At this time, based on the relationship between the flow rate Q, pressure difference Δp, and valve core displacement X of each multi-way valve, the valve core displacement parameters of each multi-way valve are corrected online, and valve core displacement control signals X1, X2, ..., X... are output. i This enables valve-controlled movement of multiple actuators, while the main controller 2 adjusts the movement based on the maximum load pressure p. LMAX Real-time pressure difference Δp of each multi-way valve 11 Δp 22 , ..., Δp jj Calculate the theoretical pressure p at the pump inlet.​sT , and the collected pump inlet pressure p s2 A pressure closed loop is formed, and the control signal is sent to the pump flow controller 4 to drive the fixed displacement pump 7 to provide the required flow rate of the system, satisfying the following equation:

[0066] p s2 =p L1 +Δp 11 =p L2 +Δp 22 =…=p Lk +Δp jj ;

[0067] In the formula: p s2 Indicates the pressure at the second pump inlet; p L1 Indicates the real-time load pressure of the first actuator; Δp 11 This indicates the real-time differential pressure of the first multi-way valve; p L2 Indicates the real-time load pressure of the second actuator; Δp 22 This indicates the real-time differential pressure of the second multi-way valve; p Lk Δp represents the real-time load pressure of the k-th actuator. jj The real-time differential pressure of the j-th multi-way valve is represented by k; the actuator number is represented by k∈(1,i); and the multi-way valve number is represented by j∈(1,i).

[0068] By using a pump-valve composite control flow distribution strategy, a composite action control strategy is achieved to match the system flow with the variable speed drive of the pump flow controller.

[0069] The pressure compensation controller 16 receives control signals from the main controller 2. It collects in real-time inlet and outlet pressures, pump inlet pressures, and valve core displacement signals from the multi-way valves 10.1 and 10.2 of each actuator via pressure sensors 13.1, 14.1, 13.2, and 14.2, and displacement sensors 15.1 and 15.2. It also calculates the pressure difference and flow rate of each actuator's multi-way valve in real-time and transmits this data to the main controller 2. When the actuator operates alone, it outputs the maximum valve core control signal Xmax to fully open the multi-way valve, thus controlling the actuator's movement. During combined actuator actions, it corrects the valve core displacement control signals X1, X2, ..., X... in real-time online. i This enables pressure compensation and valve-controlled movement of multiple actuators.

[0070] S3: Controls the actuator's compound action to achieve compound control of multi-way valve variable speed pump valve.

[0071] When actuator 11 performs a compound action, pressure compensation controller 16 stores the relationship between the flow rate Q of each multi-way valve, the differential pressure signal Δp of the multi-way valve, and the valve core displacement control signal X obtained through experiments in the pressure compensation controller, and controls the differential pressure Δp between the inlet and outlet of the multi-way valve. i The multi-way valve j valve core displacement control signal X jSatisfy the following formula:

[0072]

[0073] In the formula: X j This represents the valve core displacement control signal for the multi-way valve j; Δp j0 Indicates the minimum differential pressure of multi-way valve j; x j This indicates the displacement of the valve core before correction in the multi-way valve j.

[0074] This ensures that the flow rate through the multi-way valve remains unchanged regardless of the load pressure, thereby achieving pressure compensation.

[0075] When actuator 11 is in a compound operation state, pressure compensation controller 16 calculates the flow rates Q1, Q2, ..., Q of each multi-way valve in real time. i Satisfying Q1 + Q2 + ... + Q i =Q smax At this time, the system is in a flow saturation state, and the main controller 2 outputs signals α1, α2, ..., α3 to the actuator control handle 1. i The anti-saturation algorithm is applied to reduce the output signal proportionally, resulting in a new output signal α'. k As shown below:

[0076]

[0077] In the formula: α' k This represents the processed output signal of the k-th actuator control handle; α max The theoretical maximum output Q of the system's fixed displacement pump is represented by... smax The corresponding maximum theoretical output signal of the control handle; This represents the summation of the actual output signals of the control handle; α k This indicates the output signal of the control handle of the k-th actuator; i represents the total number of actuators.

[0078] The new output signals α1', α'2, ..., α′ are... i The output signal of actuator control handle 1, which replaces S22, continues to execute the compound motion control strategy according to S22, ensuring the coordinated movement of multiple actuators; such as Figure 6 The diagram shown is a schematic of the multi-actuator variable speed pump-valve composite control system of the present invention.

[0079] The related technology of this patent has been applied to the composite control system of luffing and telescopic pump valves of a certain type of truck crane, verifying the reliability of the technology. The basic parameters of the composite control system are as follows: the maximum speed limit of the motor is 2200 r / min, the displacement of the double-unit fixed displacement pump is 126 ml / r, the output signal range of the electric control handle is 300-700 mA, and the maximum flow rate of both the luffing and telescopic multi-way valves is 277.2 L / min, with the valve core opening of the multi-way valve being linearly related to the output signal of the electric control handle. During composite operation, the output signals of three sets of luffing and extension control handles are given under both unsaturated and saturated flow conditions. Sensors are used to collect the pump outlet flow rate, luffing flow rate, extension flow rate, and motor speed. The flow distribution is shown in Table 1. It is concluded that when the system flow is unsaturated, the luffing and extension flow rates are directly determined by the valve opening controlled by the control handle output signal, and the motor speed matches the required system flow rate. It was found that when the system flow is saturated, the starting and extending flow rates are determined by the valve opening controlled by the signal output signal of the control handle after being proportionally reduced by the anti-saturation algorithm, and the motor speed is close to the maximum limit value.

[0080] Table 1. Flow distribution table for the combined action of amplitude extension.

[0081]

[0082] The second aspect of the present invention proposes a control system for a multi-actuator variable speed pump-valve composite control method for hydraulic control, which can be used in a multi-actuator variable speed pump-valve composite control system. The system consists of a controller electric control handle 1, a main controller 2, a pump flow control unit 3, a pressure compensation controller unit 9, and an actuator 11.

[0083] The actuator electric control handle 1 includes a first actuator electric control handle 1.1, a second actuator electric control handle 1.2, and an nth actuator electric control handle 1.n, which outputs control signals to the main controller 2 according to the working conditions.

[0084] The main controller 2 identifies the motion state of the actuator 11 and selects and coordinates the control strategy.

[0085] The pump flow control unit 3 receives the control signal from the main controller 2 and controls the servo motor 6 to drive the metering pump 7 to output pressure and flow. The overflow valve 8 provides overload protection.

[0086] The pressure compensator control unit 9 receives control signals from the main controller 2 and, according to the control strategy, controls the valve core displacement of the first multi-way valve 10.1, the second multi-way valve 10.2, and the nth multi-way valve 10.n, as well as processes and transmits differential pressure signals.

[0087] The actuator 11 includes a first actuator 11.1, a second actuator 11.2, and an nth actuator 11.n, which are hydraulic cylinders, hydraulic motors, or any combination of both, to convert pressure energy into mechanical energy to perform external work.

[0088] In summary, the prediction results of the multi-actuator variable speed pump-valve composite control method used in this case demonstrate its excellent effectiveness.

[0089] (1) The embodiments of the present invention employ a variable speed pump-valve composite control system. Compared with the complex variable mechanism and pressure detection pipeline of traditional load-sensitive pumps, the composite control system does not require a preset pressure margin, which improves the stability and dynamic response of the composite control system and reduces energy loss. By adopting a multi-actuator single-action and composite action degree control strategy adapted to the variable speed pump-valve composite control system, energy loss is further reduced by coordinating the pump speed and valve opening.

[0090] (2) The embodiments of the present invention use a pressure compensation controller to control the displacement of the valve core of the multi-way valve to realize the pressure compensation function when the system load is different. Compared with the structure of the traditional pressure compensator, the pressure loss is reduced.

[0091] (3) The embodiments of the present invention show that the flow distribution of the amplitude extension composite action under the conditions of unsaturated flow and saturated flow is good in actual application and can meet the control requirements under actual working conditions.

[0092] The embodiments described above are merely preferred embodiments of the present invention and are not intended to limit the scope of the present invention. Various modifications and improvements made by those skilled in the art to the technical solutions of the present invention without departing from the spirit of the present invention should fall within the protection scope defined by the claims of the present invention.

Claims

1. A method for hydraulic control of a multi-actuator variable speed pump-valve compound control, characterized in that, It comprises the following steps: Step 1: identify the motion state of the variable speed pump valve actuator; Obtain the output signal α1 of the first actuator and the output signal α2 of the second actuator, up to the output signal α of the nth actuator. n When k = f(α) i When k = f(α) = 1, i = 1, 2, ..., n, the motion state recognition result is single-action actuator; when k = f(α) i When k = f(α) ≥ 2, i = 1, 2, ..., n, the motion state recognition result is a compound action of the actuator; when k = f(α) ≥ 2, i = 1, 2, ..., n, the motion state recognition result is a compound action of the actuator. i When (≠0)=0, i=1,2,…,n, the motion state recognition result is standby state; Step 2: selection and coordination of multi-actuator variable speed pump valve control strategy; The motion state recognition result in step 1 is obtained, the control strategy of single-acting actuator is determined as single-acting control strategy; The control strategy of composite action of actuator is determined as composite action control strategy; The standby state does not need to start the control strategy; Step 21: the single-acting control strategy adopts full opening of the multi-way valve port, and the pump flow controller controls the speed of the servo motor to realize the single-acting control strategy of the variable speed pump controlled actuator motion; When the actuator is in single-acting state, the main controller controls the pump flow controller output basic flow according to the opening signal of the electric control handle of the actuator to build pressure of the system, the pressure compensation controller outputs the maximum spool control signal Xmax to control the multi-way valve port to be fully open, the pressure sensor collects the multi-way valve inlet and outlet pressures p1 and p2 and the pump port pressure p s1 in real time, calculates the multi-way valve pressure difference signal Δp = p1-p2 in real time and transmits it to the main controller, and calculates the pump port theoretical pressure p L in real time according to the load pressure p sT and the multi-way valve pressure difference signal Δp, and outputs the signal to the pump flow controller to drive the quantitative pump to change the valve port pressure difference by controlling the pump port pressure in real time, so that the following formula is met: p s1 = p L + Δp = p L + (p1-p2); where: p s1 represents the first pump port pressure; p L represents the load pressure; Δp represents the multi-way valve pressure difference signal; p1 represents the first multi-way valve inlet and outlet pressure; p2 represents the second multi-way valve inlet and outlet pressure; Through variable speed pump control flow, the single-acting control strategy of actuator motion is realized; Step 22: the composite action control strategy selects to take the pressure compensation controller to realize real-time online correction of the displacement of the multi-way valve spool, controls the opening of the valve port of the valve controlled multi-actuator to realize the valve controlled multi-actuator motion, and the pump flow controller variable speed drive pump matches the system flow; The actuator composite action state, actuator control handle output signal is α1, α2, …, α i , pump flow controller first according to the actuator electric control handle output signal preset servo motor speed, control servo motor drive quantitative pump output system basic flow, pressure compensation controller through the pressure sensor and displacement sensor acquisition multiway valve pressure signal and displacement signal, real-time calculation of multiway valve flow Q1, Q2, …, Q i And differential pressure Δp 11 , Δp 22 , …, Δp jj , when Q1+Q2+…+Q i <Q smax , Q smax For the system quantitative pump maximum output flow, the system is in flow unsaturated state, at this time according to the relationship between the multiway valve flow Q, differential pressure Δp and valve core displacement X, online correction multiway valve core displacement parameters, output valve core displacement control signal X1, X2, …, X i , realize valve control multi actuator movement, while the main controller according to the maximum load pressure p LMAX And multiway valve real-time differential pressure Δp 11 , Δp 22 , …, Δp jj Calculate pump port theoretical pressure p sT , with the acquisition of pump port pressure p s2 Form a closed loop of pressure, control signal to pump flow controller, drive quantitative pump to provide the required flow of the system, so that it satisfies the following formula: p s2 = p L1 + Δp 11 = p L2 + Δp 22 =... = p Lk + Δp jj ; where: p s2 represents the second pump port pressure; p L1 represents the first actuator real-time load pressure; Δp 11 represents the first multi-way valve real-time pressure difference; p L2 represents the second actuator real-time load pressure; Δp 22 represents the second multi-way valve real-time pressure difference; p Lk represents the actuator k real-time load pressure; Δp jj represents the multi-way valve j real-time pressure difference; k represents the actuator number, k ∈ (1, i); j represents the multi-way valve number, j ∈ (1, i); Through pump valve composite control flow distribution, the composite action control strategy of pump flow controller variable speed drive pump matching system flow is realized; Step 3: control the composite action of the actuator to realize the variable speed pump valve composite control of the multi-way valve; When the actuator is in a compound action state, the pressure compensation controller calculates the flow rates Q1, Q2, ..., Q of the multi-way valve in real time. i Satisfying Q1 + Q2 + ... + Q i =Q smax At this time, the system is in a flow saturation state, and the main controller outputs signals α1, α2, ..., α3 to the actuator control handle. i The anti-saturation algorithm is applied to reduce the output signal proportionally, resulting in a new output signal α'. k As shown below: wherein: α k represents the kth actuator control handle output signal after processing; α max represents the maximum output theoretical Q of the system quantitative pump smax corresponding to the control handle maximum theoretical output signal; (k = 1, 2, …, i) represents the sum of the control handle actual output signals; α k represents the kth actuator control handle output signal; i represents the total number of actuators; The new output signals α'1, α'2,..., α'n are then compared with the reference signals α1, α2,..., αn in step 23. i The control handle output signals are replaced by the new output signals α'1, α'2,..., α'n, and the compound motion control strategy is continued to be executed in step 22 to ensure the motion coordination of the multiple actuators.

2. The multi-actuator variable speed pump-valve compound control method for hydraulic control according to claim 1, characterized in that, The step multi-actuator variable speed pump valve composite control method is specifically: The main controller collects the opening signal of each actuator electric control handle, identifies the motion state of each actuator according to step 1, coordinates the pressure compensation controller and the pump flow controller to realize the control strategy of single-acting or composite action of the actuator according to step 2, and realizes the anti-saturation algorithm processing of the control handle output signal according to step 3.

3. The multi-actuator variable speed pump-valve compound control method for hydraulic control according to claim 1, wherein, The pump flow controller in step 2 is used for receiving the speed control signal of the main controller and receiving the encoder speed feedback signal at the same time, forming a servo motor speed closed loop control, and finally controlling the servo motor to drive the quantitative pump to output the required flow of the system.

4. The multi-actuator variable speed pump-valve compound control method for hydraulic control according to claim 1, wherein, The pressure compensation controller in the step 2 and step 3 is used for receiving the main controller control signal, collecting the inlet and outlet pressure of each actuator multi-way valve, the pump mouth pressure and the multi-way valve spool displacement signal in real time through the pressure sensor and displacement sensor, calculating the pressure difference and flow of each actuator multi-way valve in real time and transmitting to the main controller, outputting the maximum valve core control signal Xmax to control the multi-way valve port full opening when the actuator is single-acting, realizing the pump control actuator movement; when the actuator is compound-acting, the multi-way valve spool displacement control signal X1, X2, …, X i is corrected in real time online, realizing the pressure compensation and valve control multi-actuator movement.

5. The multi-actuator variable speed pump-valve compound control method for hydraulic control according to claim 1, wherein, The composite action process of the actuator in step 3 is specifically: The actuator composite action pressure compensation controller stores the relationship between the multi-way valve flow Q, the multi-way valve pressure difference signal Δp and the spool displacement control signal X obtained through experiments in the pressure compensation controller, controls the pressure difference Δp between the inlet and outlet of the multi-way valve i , so that the multi-way valve j spool displacement control signal X j satisfies the following formula: wherein: X j represents the minimum pressure differential of the multi-way valve j; x j0 represents the minimum pressure differential of the multi-way valve j; x j represents the minimum pressure differential of the multi-way valve j; x The flow through the multi-way valve port does not change with the change of load pressure, and the pressure compensation effect is achieved.

6. A control system for implementing the multi-actuator variable speed pump-valve compound control method for hydraulic control according to claim 1, characterized in that, It can be used for multi-actuator variable speed pump valve composite control system, which is composed of electric control handle, main controller, pump flow control unit, pressure compensation controller unit and actuator; The actuator electric control handle includes first, second and nth actuator electric control handles, which outputs control signal to the main controller according to the working condition demand; The main controller realizes the identification of the motion state of the actuator and the selection and coordination of the control strategy; The pump flow control unit receives the control signal of the main controller, controls the servo motor to drive the quantitative pump to output pressure and flow, and the overflow valve plays the role of overload protection; The pressure compensator control unit receives the control signal of the main controller, controls the displacement of the first, second and nth multi-way valve spools according to the control strategy, and processes and transmits the pressure difference signal; The actuator includes first, second and nth actuators, which are hydraulic cylinders or hydraulic motors or any combination of the two, and realize the conversion of pressure energy into mechanical energy to do work outside.

Images