Hybrid load-sensing electro-hydraulic system and control method thereof

Abstract

The present invention provides a hybrid load-sensitive electro-hydraulic system and a control method thereof, wherein a dual-power actuator comprises a second hydraulic actuator and a load-balancing actuator connected in parallel, a battery is connected to a prime mover through a first inverter, and is connected to a load-balancing actuator through a second inverter, the prime mover is connected to a load-sensitive pump, the load-sensitive pump is connected to a first hydraulic actuator through a first multi-way valve, and is connected to a second hydraulic actuator through a second multi-way valve, and a first pressure sensor and a second pressure sensor are respectively arranged at the oil inlet and the oil outlet of the second hydraulic actuator; a control device is respectively connected to the first pressure sensor, the second pressure sensor, the third pressure sensor, the motor of the load-balancing actuator, and an oil control component in the prime mover and the load-sensitive pump. The present invention can recover the energy loss and system potential energy caused by throttling on the pressure compensation valve.

Description

Technical Field

[0001] The invention belongs to the technical field of hydraulic transmission and control, and in particular relates to a hybrid load-sensitive electro-hydraulic system and a control method thereof. Background Art

[0002] In today's international community, which emphasizes energy conservation and emission reduction, the large energy loss and low efficiency of hydraulic transmission systems are key issues that restrict their development. Load-sensitive control technology adopts the principle of pressure feedback, and adjusts the variable pump in real time according to the load pressure of the actuator to achieve a balance between the supply and demand of the system flow, which can effectively improve the efficiency of the hydraulic transmission system and reduce energy consumption. However, there are still the following problems in the application of load-sensitive control technology: when the load-sensitive pump supplies oil to multiple actuators, it is necessary to control the output pressure of the pump based on the maximum load pressure of each actuator. Due to the load difference between the actuators, each actuator branch requires a pressure compensation valve to adjust the pressure on the branch to the load pressure to match the branch load, which inevitably leads to a large throttling loss on the pressure compensation valve, wasting a lot of energy. In addition, there is potential energy that can be recovered during the operation of the system, and the traditional load-sensitive technology has a low recovery rate for this part of the potential energy. Therefore, how to eliminate the load difference during the compound action of multiple actuators, recover potential energy, and improve the energy utilization efficiency of the system is a problem that the present invention needs to solve. Summary of the invention

[0003] The present invention provides a hybrid load-sensitive electro-hydraulic system and a control method thereof, so as to solve the energy loss problem caused by load imbalance among actuators in the current load-sensitive control system.

[0004] According to a first aspect of an embodiment of the present invention, a hybrid load-sensitive electro-hydraulic system is provided, comprising a battery, a first inverter, a second inverter, a prime mover, a load-sensitive pump, a dual-power actuator and a first hydraulic actuator, wherein the dual-power actuator comprises a second hydraulic actuator and a load-balancing actuator connected in parallel, wherein the battery is connected to the prime mover via the first inverter and to the load-balancing actuator via the second inverter, wherein the prime mover is connected to the load-sensitive pump, wherein the load-sensitive pump is connected to the first hydraulic actuator via a first multi-way valve and to the second hydraulic actuator via a second multi-way valve, wherein a first pressure sensor and a second pressure sensor are respectively provided at an oil inlet and an oil outlet of the second hydraulic actuator;

[0005] The control device is respectively connected to the first pressure sensor, the second pressure sensor, the third pressure sensor, the motor of the load balancing actuator, and an oil control component in the prime mover and the load sensitive pump. The control device first determines the mode of the dual-power actuator according to the pressures detected by the first pressure sensor and the second pressure sensor and the received action signal, and obtains the load pressure p1 of the second hydraulic actuator according to the pressures detected by the first pressure sensor and the second pressure sensor and the determined mode. According to the action signal, the load pressure p1 and the maximum load pressure p2 of the first hydraulic actuator detected by the third pressure sensor, the oil control component and the motor are respectively controlled. The oil control component adjusts the amount of oil output by the load sensitive pump, and the motor adjusts the size and direction of the force or torque output by the load balancing actuator, so that the load balancing actuator can recover the throttling loss caused by the load difference of each actuator and the potential energy generated in the process of the dual-power actuator driving the load to the battery.

[0006] In an optional implementation, when there is only one first hydraulic actuator, the third pressure sensor is provided at the load feedback port of the first multi-way valve, and the maximum load pressure p2 is the load pressure of the first hydraulic actuator;

[0007] When there are multiple first hydraulic actuators, for every two adjacent first hydraulic actuators in sequence, a first shuttle valve is provided between the two adjacent first hydraulic actuators, the first oil inlet of the first shuttle valve is connected to the load feedback port of the first multi-way valve corresponding to one of the first hydraulic actuators, the second oil inlet is connected to the oil outlet of the next first shuttle valve, and the oil outlet is connected to the second oil inlet of the previous first shuttle valve, wherein only the oil outlet of the first first shuttle valve is connected to the third pressure sensor, and only the second oil inlet of the last first shuttle valve is connected to the load feedback port of the first multi-way valve corresponding to another first hydraulic actuator, and the maximum load pressure p2 is the maximum load pressure among the multiple first hydraulic actuators.

[0008] In another optional implementation, when there is only one first hydraulic actuator, a second pressure compensating valve is further provided between the second multi-way valve and the load-sensitive pump, and a load feedback port of the second multi-way valve is connected to a pilot port of the second pressure compensating valve, and a first pressure compensating valve is further provided between the first multi-way valve and the load-sensitive pump, and a load feedback port of the first multi-way valve is connected to a pilot port of the first pressure compensating valve;

[0009] It also includes a second shuttle valve, the first oil inlet of the second shuttle valve is connected to the load feedback port of the second multi-way valve, the second oil inlet is connected to the load feedback port of the first multi-way valve, the oil outlet of the second shuttle valve is connected to the load sensitive pump or the fourth pressure sensor, and the oil outlet of the second shuttle valve screens out the maximum load pressure of the dual-power actuator and the first hydraulic actuator; in the case where the load difference exceeds the maximum balancing power of the load balancing actuator, resulting in an abnormal working state of the system, the control device adjusts the speed of the prime mover according to the pressure detected by the fourth pressure sensor, or the load sensitive pump adjusts its displacement by itself, so that the prime mover drives the load sensitive pump to provide a corresponding amount of oil, so that the system pressure output by the load sensitive pump matches the maximum load pressure of the dual-power actuator and the first hydraulic actuator, and the first pressure compensation valve or the second pressure compensation valve is used to adjust the pressure provided to the first hydraulic actuator or the second hydraulic actuator;

[0010] When there are multiple first hydraulic actuators, a second pressure compensating valve is further provided between the second multi-way valve and the load-sensitive pump, and a load feedback port of the second multi-way valve is connected to a pilot port of the second pressure compensating valve. For each first hydraulic actuator, a corresponding first pressure compensating valve is further provided between the first multi-way valve corresponding to the first hydraulic actuator and the load-sensitive pump, and a load feedback port of each first multi-way valve is connected to a pilot port of the corresponding first pressure compensating valve.

[0011] It also includes a second shuttle valve, the first oil inlet of the second shuttle valve is connected to the load feedback port of the second multi-way valve, and the second oil inlet is connected to the oil outlet of the first shuttle valve; the oil outlet of the second shuttle valve is connected to the load sensitive pump or the fourth pressure sensor, and the oil outlet of the second shuttle valve screens out the maximum load pressure of the dual-power actuator and the multiple first hydraulic actuators; when the load difference exceeds the maximum balancing power of the load balancing actuator, resulting in an abnormal working state of the system, the control device adjusts the speed of the prime mover according to the pressure detected by the fourth pressure sensor, or the load sensitive pump adjusts its displacement by itself, so that the prime mover drives the load sensitive pump to provide a corresponding amount of oil, so that the system pressure output by the load sensitive pump matches the maximum load pressure of the dual-power actuator and the multiple first hydraulic actuators, and each of the first pressure compensation valves or the second pressure compensation valves is used to adjust the pressure provided to the corresponding first hydraulic actuator or second hydraulic actuator.

[0012] In another optional implementation, the dual-power actuator is a dual-power cylinder composed of a hydraulic cylinder and an electric cylinder in parallel, or a hydraulic cylinder and an electrostatic hydraulic actuator in parallel, or a dual-power motor composed of a hydraulic motor and an electric motor in parallel; the load balancing actuator is an electric cylinder or an electrostatic hydraulic actuator or an electric motor.

[0013] In another optional implementation, the prime mover is an electric motor or an engine; and the first hydraulic actuator is a hydraulic cylinder or a hydraulic motor.

[0014] In another optional implementation, the oil outlet of the load-sensing pump is connected to the first oil inlet of the corresponding first multi-way valve, the oil outlet of the first multi-way valve is connected to the oil inlet of the first hydraulic actuator, and the oil outlet of the first hydraulic actuator is connected to the second oil inlet of the first multi-way valve;

[0015] The oil outlet of the load-sensing pump is also connected to the oil inlet of the corresponding second multi-way valve, the oil outlet of the second multi-way valve is connected to the oil inlet of the corresponding second hydraulic actuator, and the oil outlet of the second hydraulic actuator is connected to the second oil inlet of the second multi-way valve.

[0016] According to a second aspect of an embodiment of the present invention, a control method for the hybrid load-sensing electro-hydraulic system is also provided, characterized in that the control device performs system control according to the following steps:

[0017] Step S100, after receiving the action signal, judging whether the system is in a dual-power actuator single action state or a dual-power actuator and a first hydraulic actuator combined action state according to the action signal, and sending the action signal to the multi-way valves corresponding to the dual-power actuator and the first hydraulic actuator, so that each multi-way valve is switched, thereby switching the system to the corresponding action state;

[0018] Step S200, calculating the force or torque of the second hydraulic actuator according to the two-chamber pressures of the second hydraulic actuator in the dual-power actuator detected by the first pressure sensor and the second pressure sensor, determining the direction of the current load force or torque on the dual-power actuator according to the calculated force or torque of the second hydraulic actuator and the force or torque currently output by the load balancing actuator in the dual-power actuator, determining the movement direction that the dual-power actuator will enter after the system switches to the corresponding action state according to the action signal, and judging whether the dual-power actuator is in impedance mode or in overrunning mode according to the direction of the current load force or torque and the movement direction;

[0019] Step S300, dividing the system working condition based on the action state and the mode, and controlling the oil control component and the motor according to the divided system working condition, the load pressure p1 of the second hydraulic actuator in the dual-power actuator, and the maximum load pressure p2 of the first hydraulic actuator, so that the oil control component adjusts the amount of oil output by the load-sensitive pump, and the motor adjusts the size and direction of the force or torque output by the load balancing actuator, so that the load balancing actuator can recover the throttling loss caused by the load difference of each actuator and the potential energy generated in the process of the dual-power actuator driving the load to the battery.

[0020] In an optional implementation, judging whether the dual-power actuator is in the impedance mode or the overrunning mode according to the direction of the load force or torque and the direction of movement in step S200 includes: when the direction of the load force or torque is opposite to the direction of movement, the dual-power actuator is in the impedance mode; when the direction of the load force or torque is the same as the direction of movement, the dual-power actuator is in the overrunning mode;

[0021] Before the step S300, it also includes: obtaining the load pressure p1 of the second hydraulic actuator according to the pressure detected by the first pressure sensor and the second pressure sensor and the determined mode, and the load pressure p1 is the oil inlet end pressure of the dual-power actuator; when the dual-power actuator is a dual-power cylinder, if the mode is an overrunning mode, the load pressure p1 is the pressure detected by the corresponding pressure sensor connected to the rodless chamber in the second hydraulic actuator; if the mode is an impedance mode, the load pressure p1 is the pressure detected by the corresponding pressure sensor connected to the rod chamber in the second hydraulic actuator.

[0022] In another optional implementation, the step S300 specifically includes:

[0023] When the system is in the working condition of: when the dual-power actuator acts alone in the impedance mode, the motor of the load-balancing actuator cannot work in the generator mode, and the motor of the load-balancing actuator is controlled not to act. Under the premise that the second pressure compensation valve corresponding to the dual-power actuator does not act, the control device adjusts the speed of the prime mover, or the load-sensitive pump adjusts its displacement automatically, so that the prime mover drives the load-sensitive pump to provide a corresponding amount of oil. At this time, the second hydraulic actuator bears all the load and drives the load-balancing actuator to follow the movement;

[0024] When the system operating condition is that the dual-power actuator operates alone in the override mode, control the motor to drive the load balancing actuator to output a corresponding force or torque in the direction opposite to the load, so that the load balancing actuator bears all the loads. The load balancing actuator operates in the generator mode, and on the premise that the corresponding second pressure compensating valve of the dual-power actuator does not operate, adjust the speed of the prime mover by the control device, or the load-sensing pump adjusts its displacement by itself, so that the prime mover drives the load-sensing pump to provide a corresponding amount of oil, thereby realizing the movement of the second hydraulic actuator following the load balancing actuator;

[0025] When the system operating condition is that the dual-power actuator operates in the impedance mode and combines with the first hydraulic actuator, compare the load pressure p1 with the maximum load pressure p2 of the first hydraulic actuator detected by the third pressure sensor:

[0026] If p1 > p2, on the premise that the corresponding second pressure compensating valve of the dual-power actuator does not operate, control the motor to drive the load balancing actuator to output a corresponding force or torque in the same direction as the movement of the second hydraulic actuator and in the direction opposite to the load. Let the difference between p1 and p2 be the first pressure, and the force or torque output by the load balancing actuator is equal to the force or torque output by the second hydraulic actuator when the load applies the first pressure to the second hydraulic actuator. Adjust the speed of the prime mover by the control device, or the load-sensing pump adjusts its displacement by itself, so that the prime mover drives the load-sensing pump to output a corresponding amount of oil, so that the system pressure output by the load-sensing pump matches the maximum load pressure p2. At this time, the load balancing actuator operates in the energy-consuming mode;

[0027] If p1 < p2, on the premise that the corresponding second pressure compensating valve of the dual-power actuator does not operate, control the motor to drive the load balancing actuator to output a corresponding force or torque in the direction opposite to the movement of the second hydraulic actuator and in the same direction as the load. Let the difference between p2 and p1 be the second pressure, and the force or torque output by the load balancing actuator is equal to the force or torque output by the second hydraulic actuator when the load applies the second pressure to the second hydraulic actuator. Adjust the speed of the prime mover by the control device, or the load-sensing pump adjusts its displacement by itself, so that the prime mover drives the load-sensing pump to provide a corresponding amount of oil, so that the system pressure output by the load-sensing pump matches the maximum load pressure p2. At this time, the load balancing actuator operates in the generator mode;

[0028] When the system operating condition is: when the dual-power actuator acts in combination with the first hydraulic actuator in an overrunning mode, the control device adjusts the rotational speed of the prime mover, or the load-sensitive pump automatically adjusts its displacement, so that the prime mover drives the load-sensitive pump to output a corresponding amount of oil, so that the system pressure output by the load-sensitive pump matches the maximum load pressure p2. Under the premise that the corresponding second pressure compensation valve of the dual-power actuator does not act, the motor drives the load-balancing actuator to output a force or torque of a corresponding magnitude opposite to the movement direction of the second hydraulic actuator and opposite to the load direction. The force or torque output by the load-balancing actuator is equal to the sum of the force or torque output by the second hydraulic actuator when the load applies the load pressure p1 to the second hydraulic actuator and the force or torque output by the second hydraulic actuator when the load applies p2 to the second hydraulic actuator. At this time, the load-balancing actuator operates in generator mode.

[0029] In another optional implementation, in step S100, when it is determined according to the action signal that the dual-power actuator is not in action, the control device adjusts the speed of the prime mover, or the load-sensitive pump adjusts its displacement by itself, so that the prime mover drives the load-sensitive pump to provide a corresponding amount of oil, so that the system pressure output by the load-sensitive pump matches the maximum load pressure in the dual-power actuator and the first hydraulic actuator, and each of the first pressure-compensating valves or the second pressure-compensating valves adjusts the pressure provided to the corresponding first hydraulic actuator or the second hydraulic actuator.

[0030] The beneficial effects of the present invention are:

[0031] 1. In the present invention, the second hydraulic actuator and the load balancing actuator in the dual-power actuator jointly bear the external load borne by the dual-power actuator, so that the sum of the output force or torque of the second hydraulic actuator and the load balancing actuator is equal to the external load borne by the dual-power actuator. By adjusting the output force or torque of the load balancing actuator, the pressure required for the second hydraulic actuator to bear the corresponding part of the load can be changed, so that the load pressure of the second hydraulic actuator and the first hydraulic actuator on other branches can be matched. It can be seen that the load balancing actuator can compensate for the load difference of each hydraulic actuator, so that the load pressure on each branch is similar, which can reduce the output power of the load sensitive pump and reduce the throttling loss of the pressure compensation valve on the branch; the present invention utilizes the characteristic that the motor of the load balancing actuator can work in the generator mode, and can recover the potential energy in the system and the energy that would have been consumed on the pressure compensation valve due to the load difference, thereby improving the energy efficiency of the system;

[0032] 2. In the present invention, when there is only one first hydraulic actuator, even if the load difference exceeds the maximum balancing power of the load balancing actuator, normal operation of each actuator can be achieved;

[0033] 3. When there are multiple first hydraulic actuators, the load balancing actuator in the dual-power actuator can also be used to recover the system potential energy and the energy originally consumed by the pressure compensation valve;

[0034] 4. When there are multiple first hydraulic actuators, the present invention can achieve normal operation of each actuator even if the load difference exceeds the maximum balancing power of the load balancing actuator. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Figure 1 It is a schematic structural diagram of an embodiment of a hybrid load-sensitive electro-hydraulic system of the present invention;

[0036] Figure 2 It is the energy consumption characteristic diagram of the traditional load-sensitive system;

[0037] Figure 3 It is the energy consumption characteristic diagram of the dual-power actuator in the present invention under four working conditions;

[0038] Figure 4 It is a schematic structural diagram of an embodiment of the dual-power actuator of the present invention;

[0039] Figure 5 It is a structural schematic diagram of another embodiment of the dual-power actuator of the present invention;

[0040] Figure 6 It is a structural schematic diagram of another embodiment of the dual-power actuator of the present invention;

[0041] Figure 7 It is a structural schematic diagram of another embodiment of the dual-power actuator of the present invention;

[0042] Figure 8 It is a schematic structural diagram of another embodiment of the hybrid load-sensing electro-hydraulic system of the present invention;

[0043] Fig. 9 It is a structural schematic diagram of another embodiment of the hybrid load-sensitive electro-hydraulic system of the present invention;

[0044] Fig.10 It is a flow chart of an embodiment of the hybrid load-sensitive electro-hydraulic system control method of the present invention. DETAILED DESCRIPTION

[0045] In order to enable those skilled in the art to better understand the technical solutions in the embodiments of the present invention and to make the above-mentioned purposes, features and advantages of the embodiments of the present invention more obvious and understandable, the technical solutions in the embodiments of the present invention are further described in detail below in conjunction with the accompanying drawings.

[0046] In the description of the present invention, unless otherwise specified and limited, it should be noted that the term "connection" should be understood in a broad sense. For example, it can be a mechanical connection or an electrical connection, or it can be the internal connection between two elements. It can be a direct connection or an indirect connection through an intermediate medium. For ordinary technicians in this field, the specific meanings of the above terms can be understood according to specific circumstances.

[0047] like Figure 1 The figure shows a schematic diagram of the structure of an embodiment of a hybrid load-sensitive electro-hydraulic system of the present invention. The hybrid load-sensitive electro-hydraulic system may include a battery 1, a first inverter 2-1, a second inverter 2-2, a prime mover 3, a load-sensitive pump 4, a dual-power actuator 7 and a first hydraulic actuator 8. The dual-power actuator 7 may include a second hydraulic actuator and a load-balancing actuator connected in parallel. The battery 1 is connected to the prime mover 3 through the first inverter 2-1 and to the load-balancing actuator through the second inverter 2-2. The prime mover 3 is connected to the load-sensitive pump 4. The load-sensitive pump 4 is connected to the first hydraulic actuator 8 through a first multi-way valve 6-1 and to the second hydraulic actuator through a second multi-way valve 6-2. The oil inlet and the oil outlet of the second hydraulic actuator are respectively provided with a first pressure sensor 10-1 and a second pressure sensor 10-2. The control device 11 may be respectively connected to the first pressure sensor 10-1, the second pressure sensor 10-2, the third pressure sensor 10-3, the motor of the load-balancing actuator and the prime mover. The motor 3 is connected to an oil control component in the load-sensitive pump 4, which first determines the mode of the dual-power actuator according to the pressures detected by the first pressure sensor 10-1 and the second pressure sensor 10-2 and the received action signal, and then obtains the load pressure p1 of the second hydraulic actuator according to the pressures detected by the first pressure sensor and the second pressure sensor and the determined mode. According to the action signal, the load pressure p1 and the maximum load pressure p2 of the first hydraulic actuator 8 detected by the third pressure sensor 10-3, the oil control component and the motor are controlled respectively, and the oil control component adjusts the amount of oil output by the load-sensitive pump 4, and the motor adjusts the size and direction of the force or torque output by the load balancing actuator, so that the load balancing actuator can recover the throttling loss caused by the load difference of each actuator and the potential energy generated in the process of the dual-power actuator 7 driving the load to the battery 1.

[0048] In this embodiment, when there is only one first hydraulic actuator, the third pressure sensor 10-3 can be arranged at the load feedback port of the first multi-way valve 6-1, and the maximum load pressure p2 is the load pressure of the first hydraulic actuator. The oil outlet of the load-sensitive pump 4 can be connected to the first oil inlet of the corresponding first multi-way valve 6-1, and the oil outlet of the first multi-way valve 6-1 can be connected to the oil inlet of the first hydraulic actuator 8, and the oil outlet of the first hydraulic actuator 8 can be connected to the second oil inlet of the first multi-way valve 6-1; the oil outlet of the load-sensitive pump 4 can also be connected to the oil inlet of the corresponding second multi-way valve 6-2, and the oil outlet of the second multi-way valve 6-2 can be connected to the oil inlet of the corresponding second hydraulic actuator, and the oil outlet of the second hydraulic actuator can be connected to the second oil inlet of the second multi-way valve 6-2. The prime mover 3 can be used to drive the load-sensitive pump 4, and the load-sensitive pump 4 is used to supply oil to all actuators.

[0049] Combination Figure 2 and Figure 3 The energy consumption characteristic diagram of the conventional load sensing system and the dual power actuator of the present invention is shown in FIG. Figure 2 It can be seen that when the traditional load sensing system supplies oil to multiple actuators, it is necessary to control the output pressure p based on the maximum load pressure of the actuator. p , and the pressure used by the low-load actuator to bear the load is only p2, so a large amount of pressure loss Δp will be generated on the pressure compensation valve c2 , and the pressure compensation valve losses Δp of the high-load actuator c1 Compared with the waste of a lot of power, there is also potential energy P under the overtaking condition. G The load-sensing system is not fully utilized, resulting in low energy efficiency when supplying oil to multiple actuators. To this end, the present invention proposes a hybrid load-sensing electro-hydraulic system, which can effectively reduce the energy loss caused by load differences, recover potential energy, and improve the energy efficiency of the system. Specifically, the control device 11 of the present invention can perform system control according to the following steps:

[0050] Step S100, after receiving the action signal, determine whether the system will be in a state of single action of the dual-power actuator 7 or a combined action state of the dual-power actuator 7 and the first hydraulic actuator 8 according to the action signal, and send the action signal to the multi-way valves corresponding to the dual-power actuator 7 and the first hydraulic actuator 8 to switch each multi-way valve, thereby switching the system to the corresponding action state.

[0051] Step S200, based on the two-chamber pressures of the second hydraulic actuator in the dual-power actuator 7 detected by the first pressure sensor 6-1 and the second pressure sensor 6-2, calculate the force or torque of the second hydraulic actuator, determine the direction of the current load force or torque on the dual-power actuator 7 based on the calculated force or torque of the second hydraulic actuator and the force or torque currently output by the load balancing actuator in the dual-power actuator 7, determine the direction of movement that the dual-power actuator 7 will enter after the system switches to the corresponding action state based on the action signal, and determine whether the dual-power actuator 7 is in impedance mode or overtaking mode based on the direction of the current load force or torque and the direction of movement.

[0052] In this step, the first pressure sensor 10-1 and the second pressure sensor 10-2 respectively arranged at the oil inlet and the oil outlet of the second hydraulic actuator are used to detect the pressure in the corresponding cavity of the second hydraulic actuator, and the control device 11 calculates the force or torque of the second hydraulic actuator according to the pressure of the two cavities of the second hydraulic actuator and the effective action area or displacement of the cavity. In step S200, judging whether the dual-power actuator 7 is in impedance mode or in overrun mode according to the direction of the load force or torque and the direction of movement includes: when the direction of the load force or torque is opposite to the direction of movement, the dual-power actuator 7 is in impedance mode; when the direction of the load force or torque is the same as the direction of movement, the dual-power actuator 7 is in overrun mode.

[0053] Before the step S300, it may also include: obtaining the load pressure p1 of the second hydraulic actuator based on the pressure detected by the first pressure sensor 10-1 and the second pressure sensor 10-2 and the determined mode, and the load pressure p1 is the pressure at the oil inlet end of the dual-power actuator. Taking the dual-power cylinder as an example, when the mode is the overrunning mode, the load pressure p1 is the pressure detected by the corresponding pressure sensor connected to the rodless chamber in the second hydraulic actuator; when the mode is the impedance mode, the load pressure p1 is the pressure detected by the corresponding pressure sensor connected to the rod chamber in the second hydraulic actuator.

[0054] Step S300: divide the system working condition based on the action state and the mode, and control the oil control component and the motor according to the divided system working condition, the load pressure p1 of the second hydraulic actuator in the dual-power actuator 7, and the maximum load pressure p2 of the first hydraulic actuator. The oil control component adjusts the oil volume output by the load-sensitive pump 4, and the motor adjusts the magnitude and direction of the force or torque output by the load-balancing actuator, so that the load-balancing actuator recovers the throttling loss caused by the load difference of each actuator and the potential energy generated during the load movement driven by the dual-power actuator 7 into the battery 1. The step S300 may specifically include:

[0055] When the system operating condition is: when the dual-power actuator acts alone in impedance mode, the motor of the load-balancing actuator cannot work in generator mode, and the motor of the load-balancing actuator is controlled not to act. Under the premise that the second pressure compensation valve corresponding to the dual-power actuator does not act, the control device adjusts the speed of the prime mover, or the load-sensitive pump adjusts its displacement by itself, so that the prime mover drives the load-sensitive pump to provide a corresponding amount of oil. At this time, the second hydraulic actuator bears all the load and drives the load-balancing actuator to follow the movement.

[0056] Under the operating conditions of the present system, since only one actuator, the dual-power actuator, is working in the system, there is no energy loss caused by load differences. In addition, since when the dual-power actuator is in impedance mode, the current load direction on the dual-power actuator is opposite to the direction of movement it is about to enter, and the motor of the load balancing actuator cannot operate in generator mode. At this time, the load balancing actuator does not work, and the second hydraulic actuator bears all the loads that the dual-power actuator needs to bear. At this time, the second hydraulic actuator also needs to drive the load balancing actuator to follow the movement synchronously. It can be seen that under the operating conditions of the present system, compared with the traditional load-sensitive system, the hybrid load-sensitive electro-hydraulic system of the present invention needs to consume more energy, but the increased energy consumption is less.

[0057] When the system operating condition is: when the dual-power actuator acts alone in the overrunning mode, the motor is controlled to drive the load-balancing actuator to output a force or torque of a corresponding magnitude opposite to the load direction, so that the load-balancing actuator bears the entire load, and the load-balancing actuator works in the generator mode. On the premise that the second pressure-compensating valve corresponding to the dual-power actuator does not act, the control device adjusts the speed of the prime mover, or the load-sensitive pump adjusts its displacement automatically, so that the prime mover drives the load-sensitive pump to provide a corresponding amount of oil, thereby realizing that the second hydraulic actuator follows the movement of the load-balancing actuator.

[0058] Under the operating conditions of this system, when the dual-power actuator is in the override mode, the current load direction on the dual-power actuator is the same as the upcoming movement direction. Therefore, the motor of the load balancing actuator can operate in the generator mode. At this time, the load balancing actuator undertakes all the loads that the dual-power actuator needs to bear, and the second hydraulic actuator only needs to follow the movement of the load balancing actuator. To ensure that the second hydraulic actuator follows the load balancing actuator, the prime mover drives the load-sensing pump to supply the corresponding amount of oil. It can be seen that under the operating conditions of this system, in the traditional load-sensing system, the second hydraulic actuator undertakes all the loads, while in the present invention, the second hydraulic actuator only needs to follow the movement of the load balancing actuator. Therefore, the pressure output by the load-sensing pump of the present invention is lower and the energy consumption is less. In addition, under the operating conditions of this system, the load balancing actuator that undertakes all the loads operates in the generator mode, and the load balancing actuator can recover the potential energy generated by the load movement while driving the load.

[0059] When the operating condition of this system is that the dual-power actuator operates in an impedance mode and combines with the first hydraulic actuator, compare the load pressure p1 with the maximum load pressure p2 of the first hydraulic actuator detected by the third pressure sensor:

[0060] If p1 > p2, on the premise that the corresponding second pressure compensating valve of the dual-power actuator does not act, control the motor to drive the load balancing actuator to output a corresponding force or torque in the same direction as the movement of the second hydraulic actuator and opposite to the load direction. Let the difference between p1 and p2 be the first pressure. The force or torque output by the load balancing actuator is equal to the force or torque output by the second hydraulic actuator when the load applies the first pressure to the second hydraulic actuator. Adjust the speed of the prime mover by the control device, or the load-sensing pump adjusts its displacement by itself, so that the prime mover drives the load-sensing pump to output a corresponding amount of oil, so that the system pressure output by the load-sensing pump matches the maximum load pressure p2. At this time, the load balancing actuator operates in the energy-consuming mode;

[0061] If p1 < p2, on the premise that the corresponding second pressure compensating valve of the dual-power actuator does not act, control the motor to drive the load balancing actuator to output a corresponding force or torque in the opposite direction to the movement of the second hydraulic actuator and in the same direction as the load direction. Let the difference between p2 and p1 be the second pressure. The force or torque output by the load balancing actuator is equal to the force or torque output by the second hydraulic actuator when the load applies the second pressure to the second hydraulic actuator. Adjust the speed of the prime mover by the control device, or the load-sensing pump adjusts its displacement by itself, so that the prime mover drives the load-sensing pump to output a corresponding amount of oil, so that the system pressure output by the load-sensing pump matches the maximum load pressure p2. At this time, the load balancing actuator operates in the generator mode.

[0062] Under the operating conditions of this system, when p1 > p2, the load pressure p1 of the second hydraulic actuator, which is the maximum load pressure of the system, is reduced to p2. Compared with the traditional load-sensing system, the pressure output by the load-sensing pump of the present invention is reduced from p P to p PE . Correspondingly, the power consumed by the load-sensing pump is reduced from P P to P PE . Since the load balance actuator operates in the energy-consuming mode when p1 > p2 and the power consumed is P E , the power consumed by the present invention is P PE plus P E . Compared with the traditional load-sensing system, the power saved by the present invention is the subtraction of P P minus P PE plus P E .

[0063] Under the operating conditions of this system, when p1 < p2, the maximum load pressure of the system is p2 at this time. The pressures delivered by the load-sensing pump to the first hydraulic actuator and the second hydraulic actuator are p2. After load balancing by the load balance actuator, the load pressure p1 of the second hydraulic actuator is increased to p2 to reduce the load difference between the actuators. At this time, it is no longer necessary for the second pressure compensation valve to throttle the pressure p2 down to p1 to achieve the load matching of the second hydraulic actuator. And at this time, the load balance actuator operates in the generator mode, and the energy loss originally generated by throttling in the pressure compensation valve in the traditional load-sensing system can be recovered by the load balance actuator to the battery.

[0064] When the system working condition is: when the dual-power actuator is in overrunning mode and acts in combination with the first hydraulic actuator, the control device adjusts the speed of the prime mover, or the load-sensitive pump adjusts its displacement automatically, so that the prime mover drives the load-sensitive pump to output a corresponding amount of oil, so that the system pressure output by the load-sensitive pump matches the maximum load pressure p2. Under the premise that the corresponding second pressure compensation valve of the dual-power actuator does not act, the motor drives the load-balancing actuator to output a corresponding force or torque in the opposite direction of the movement direction of the second hydraulic actuator and the opposite direction of the load. The force or torque output by the load-balancing actuator is equal to the load applied to the second hydraulic actuator. The sum of the force or torque output by the second hydraulic actuator when the load pressure is p1 and the force or torque output by the second hydraulic actuator when the load applies p2 to the second hydraulic actuator. At this time, the load balancing actuator works in the generator mode, wherein the control device 11 can calculate the force or torque output by the second hydraulic actuator when the load applies the load pressure p1 to the second hydraulic actuator according to the load pressure p1 and the effective action area or displacement of the cavity in the second hydraulic actuator; and can calculate the force or torque output by the second hydraulic actuator when the load applies p2 to the second hydraulic actuator according to the maximum load pressure p2 and the effective action area or displacement of the cavity in the second hydraulic actuator. Under the working condition of this system, since the dual-power actuator is in the overrunning mode, the traditional load-sensing system in this mode balances the external load by throttling the valve port, wasting a lot of potential energy. The hybrid load-sensitive electro-hydraulic system recovers the potential energy of this part of the load through a load-balancing actuator. The output pressure of the load-sensitive pump only needs to match the load pressure p2 of the first hydraulic actuator. At this time, the output force or torque of the load-balancing actuator is equal to the sum of the force or torque generated by the external load and the maximum load pressure p2 on the second hydraulic actuator. The load-balancing actuator recovers the potential energy of the external load and the energy delivered by the load-sensitive pump to the second hydraulic actuator.

[0065] In this embodiment, Figure 4 , Figure 5 , Figure 6 As shown, the dual-power actuator 7 can be a dual-power cylinder composed of a hydraulic cylinder and an electric cylinder in parallel, or a hydraulic cylinder and an electrostatic actuator in parallel, or a dual-power motor composed of a hydraulic motor and an electric motor in parallel; the prime mover can be an electric motor or an engine; the first hydraulic actuator can be a hydraulic cylinder or a hydraulic motor, wherein Figure 6 and Figure 5 The difference is Figure 6 The hydraulic cylinder of the electrostatic hydraulic actuator is a symmetrical cylinder, and two check valves for distributing oil are not required in this EHA system. Figure 7 is to Figure 6The two hydraulic cylinders are integrated together to make the whole device more compact.

[0066] It can be seen from the above embodiments that in the present invention, the second hydraulic actuator and the load balancing actuator in the dual-power actuator jointly bear the external load borne by the dual-power actuator, so that the sum of the output force or torque of the second hydraulic actuator and the load balancing actuator is equal to the external load borne by the dual-power actuator. By adjusting the output force or torque of the load balancing actuator, the pressure required for the second hydraulic actuator to bear the corresponding part of the load can be changed, so that the load pressure of the second hydraulic actuator can be matched with the load pressure of the first hydraulic actuator on other branches. It can be seen that the load balancing actuator can compensate for the load differences of each hydraulic actuator, so that the load pressures on each branch are similar, the output power of the load sensitive pump can be reduced, and the throttling loss of the pressure compensation valve on the branch can be reduced; the present invention utilizes the characteristic that the motor of the load balancing actuator can work in the generator mode, and can recover the potential energy in the system and the energy that would have been consumed in the pressure compensation valve due to load differences, thereby improving the energy efficiency of the system.

[0067] See also Figure 8 , is a schematic structural diagram of another embodiment of the hybrid load-sensitive electro-hydraulic system of the present invention. Figure 8 and Figure 1 The hybrid load-sensing electro-hydraulic system shown in the figure has only one first hydraulic actuator. The difference between the two embodiments is that: Figure 8The hybrid load-sensitive electro-hydraulic system shown may also include a first pressure-compensating valve 5-1, a second pressure-compensating valve 5-2, and a second shuttle valve 9. The first pressure-compensating valve 5-1 is arranged between the first multi-way valve 6-1 corresponding to the first hydraulic actuator 8 and the load-sensitive pump 4. The load feedback port of the first multi-way valve 6-1 is connected to the pilot port of the corresponding first pressure-compensating valve 5-1. The second pressure-compensating valve 5-2 is arranged between the second multi-way valve 6-2 and the load-sensitive pump 4. The load feedback port of the second multi-way valve 6-2 is connected to the pilot port of the second pressure-compensating valve 5-2. The first oil inlet of the second shuttle valve 9 is connected to the load feedback port of the second multi-way valve 6-2, the second oil inlet is connected to the load feedback port of the first multi-way valve 6-1, and the oil outlet of the second shuttle valve 9 is connected to the load-sensitive pump 4. 4 or the fourth pressure sensor, the oil outlet of the second shuttle valve 9 screens out the maximum load pressure in the dual-power actuator 7 and the first hydraulic actuator 8; if the load difference exceeds the maximum balancing power of the load balancing actuator, resulting in an abnormal system working state, the control device adjusts the speed of the prime mover according to the pressure detected by the fourth pressure sensor, or the load-sensitive pump adjusts its displacement by itself, so that the prime mover drives the load-sensitive pump to provide a corresponding amount of oil, so that the system pressure output by the load-sensitive pump 4 is equal to the maximum load pressure in the dual-power actuator 7 and the first hydraulic actuator 8, and the first pressure compensation valve 5-1 or the second pressure compensation valve 5-2 is used to adjust the pressure provided to the first hydraulic actuator 8 or the second hydraulic actuator.

[0068] As can be seen from the above embodiments, the second hydraulic actuator and the load balancing actuator in the dual-power actuator jointly bear the external load borne by the dual-power actuator, so that the sum of the output force or torque of the second hydraulic actuator and the load balancing actuator is equal to the external load borne by the dual-power actuator. By adjusting the output force or torque of the load balancing actuator, the pressure required for the second hydraulic actuator to bear the corresponding part of the load can be changed, so that the load pressure of the second hydraulic actuator can be matched with the load pressure of the first hydraulic actuator on other branches. It can be seen that the load balancing actuator can compensate for the load difference of each hydraulic actuator, so that the load pressure on each branch is similar, the output power of the load sensitive pump can be reduced, and the throttling loss of the pressure compensation valve on the branch can be reduced; the present invention utilizes the characteristic that the motor of the load balancing actuator can work in the generator mode, and can recover the potential energy in the system and the energy originally consumed on the pressure compensation valve due to the load difference, thereby improving the energy efficiency of the system. In addition, when there is only one first hydraulic actuator, the present invention can realize the normal operation of each actuator even if the load difference exceeds the maximum balancing power of the load balancing actuator.

[0069] See also Fig. 9, which is a structural schematic diagram of another embodiment of the hybrid load-sensitive electro-hydraulic system of the present invention. Fig. 9 and Figure 1 The hybrid load sensing electro-hydraulic system shown differs in that Fig. 9 There are multiple first hydraulic actuators 8 in the hybrid load-sensitive electro-hydraulic system shown. At this time, a second pressure compensation valve 5-2 is also provided between the second multi-way valve 6-2 and the load-sensitive pump 5. The load feedback port of the second multi-way valve 6-2 is connected to the pilot port of the second pressure compensation valve 5-2. For each first hydraulic actuator 8, a corresponding first pressure compensation valve 5-1 is also provided between the first multi-way valve 6-1 corresponding to the first hydraulic actuator 8 and the load-sensitive pump 4. The load feedback port of each first multi-way valve 6-1 is connected to the pilot port of the corresponding first pressure compensation valve 5-1; and for every two first hydraulic actuators 8 adjacent in sequence, the corresponding A first shuttle valve 14 is provided between two adjacent first hydraulic actuators 8, and a first oil inlet of the first shuttle valve 14 is connected to a load feedback port of the first multi-way valve 6-1 corresponding to one of the first hydraulic actuators 8, a second oil inlet is connected to an oil outlet of the next first shuttle valve 14, and an oil outlet is connected to a second oil inlet of the previous first shuttle valve 14, wherein only the oil outlet of the first first shuttle valve 14 is connected to the third pressure sensor 10-3, and only the second oil inlet of the last first shuttle valve 14 is connected to a load feedback port of the first multi-way valve 6-1 corresponding to another first hydraulic actuator 8, and the maximum load pressure p2 is the maximum load pressure among the multiple first hydraulic actuators 8.

[0070] Fig. 9 The hybrid load-sensitive electro-hydraulic system shown may also include a second shuttle valve 9, wherein a first oil inlet of the second shuttle valve 9 is connected to a load feedback port of the second multi-way valve 6-2, and a second oil inlet is connected to an oil outlet of the first shuttle valve 14; an oil outlet of the second shuttle valve 9 is connected to the load-sensitive pump 4 or a fourth pressure sensor, and the oil outlet of the second shuttle valve 9 screens out the maximum load pressure of the dual-power actuator 7 and the plurality of first hydraulic actuators 8; in the case where the load difference exceeds the maximum balancing power of the load balancing actuator, resulting in an abnormal working state of the system, the control device adjusts the speed of the prime mover according to the pressure detected by the fourth pressure sensor, or the load-sensitive pump adjusts its displacement by itself, so that the prime mover 3 drives the load-sensitive pump 4 to provide a corresponding amount of oil, so that the system pressure output by the load-sensitive pump 4 is equal to the maximum load pressure of the dual-power actuator 7 and the plurality of first hydraulic actuators 8, and each of the first pressure compensation valves 5-1 or the second pressure compensation valves 5-2 is used to adjust the pressure provided to the corresponding first hydraulic actuator 8 or second hydraulic actuator.

[0071] It can be seen from the above embodiments that in the present invention, the second hydraulic actuator and the load balancing actuator in the dual-power actuator jointly bear the external load borne by the dual-power actuator, so that the sum of the output force or torque of the second hydraulic actuator and the load balancing actuator is equal to the external load borne by the dual-power actuator. By adjusting the output force or torque of the load balancing actuator, the pressure required for the second hydraulic actuator to bear the corresponding part of the load can be changed, so that the load pressure of the second hydraulic actuator can be matched with the load pressure of the first hydraulic actuator on other branches. It can be seen that the load balancing actuator can compensate for the load differences of each hydraulic actuator, so that the load pressures on each branch are similar, the output power of the load sensitive pump can be reduced, and the throttling loss of the pressure compensation valve on the branch can be reduced; the present invention utilizes the characteristic that the motor of the load balancing actuator can work in the generator mode, and can recover the potential energy in the system and the energy that would have been consumed in the pressure compensation valve due to load differences, thereby improving the energy efficiency of the system. When there are multiple first hydraulic actuators, the present invention can also realize the recovery of system potential energy and energy originally consumed in the pressure compensation valve by utilizing the load balancing actuator in the dual-power actuator. Moreover, when there are multiple first hydraulic actuators, even if the load difference exceeds the balancing power of the load balancing actuator, the normal operation of each actuator can be realized.

[0072] In addition, if Fig.10 As shown, the present invention also provides a control method for the hybrid load-sensitive electro-hydraulic system, in which a control device performs system control according to the following steps:

[0073] Step S100, after receiving the action signal, judging whether the system is in a dual-power actuator single action state or a dual-power actuator and a first hydraulic actuator combined action state according to the action signal, and sending the action signal to the multi-way valves corresponding to the dual-power actuator and the first hydraulic actuator, so that each multi-way valve is switched, thereby switching the system to the corresponding action state;

[0074] Step S200, calculating the force or torque of the second hydraulic actuator according to the two-chamber pressures of the second hydraulic actuator in the dual-power actuator detected by the first pressure sensor and the second pressure sensor, determining the direction of the current load force or torque on the dual-power actuator according to the calculated force or torque of the second hydraulic actuator and the force or torque currently output by the load balancing actuator in the dual-power actuator, determining the movement direction that the dual-power actuator will enter after the system switches to the corresponding action state according to the action signal, and judging whether the dual-power actuator is in impedance mode or in overrunning mode according to the direction of the current load force or torque and the movement direction;

[0075] Step S300, dividing the system working condition based on the action state and the mode, and controlling the oil control component and the motor according to the divided system working condition, the load pressure p1 of the second hydraulic actuator in the dual-power actuator, and the maximum load pressure p2 of the first hydraulic actuator, so that the oil control component adjusts the amount of oil output by the load-sensitive pump, and the motor adjusts the size and direction of the force or torque output by the load balancing actuator, so that the load balancing actuator can recover the energy loss caused by throttling on the pressure compensation valve and the potential energy generated by the dual-power actuator in the process of driving the load to move into the battery.

[0076] In step S100, when it is determined according to the action signal that the dual-power actuator is not in action, the control device adjusts the speed of the prime mover, or the load-sensitive pump adjusts its displacement automatically, so that the prime mover drives the load-sensitive pump to provide a corresponding amount of oil, so that the system pressure output by the load-sensitive pump is equal to the maximum load pressure of the dual-power actuator and the first hydraulic actuator, and each of the first pressure-compensating valves or the second pressure-compensating valves adjusts the pressure provided to the corresponding first hydraulic actuator or the second hydraulic actuator.

[0077] It can be seen from the above embodiments that in the present invention, the second hydraulic actuator and the load balancing actuator in the dual-power actuator jointly bear the external load borne by the dual-power actuator, so that the external load borne by the dual-power actuator is equal to the sum of the output force or torque of the second hydraulic actuator and the load balancing actuator. By adjusting the output force or torque of the load balancing actuator, the pressure required for the second hydraulic actuator to output the corresponding part of the load can be changed, so that the load pressure of the second hydraulic actuator can be matched with the load pressure of the first hydraulic actuator on other branches. It can be seen that the load balancing actuator can compensate for the load differences of each hydraulic actuator, so that the load pressures on each branch are similar, the output power of the load-sensitive pump can be reduced, and the throttling loss of the pressure compensation valve on the branch can be reduced; the present invention utilizes the characteristic that the motor of the load balancing actuator can work in the generator mode, and can recover the potential energy in the system and the energy that would have been consumed in the pressure compensation valve due to load differences, thereby improving the energy efficiency of the system.

[0078] Those skilled in the art will readily appreciate other embodiments of the present invention after considering the specification and practicing the invention disclosed herein. This application is intended to cover any variations, uses or adaptations of the present invention that follow the general principles of the present invention and include common knowledge or customary techniques in the art that are not disclosed by the present invention. The specification and examples are to be considered exemplary only, and the true scope and spirit of the present invention are indicated by the following claims.

[0079] It should be understood that the present invention is not limited to the exact construction that has been described above and shown in the drawings and that various modifications and changes may be made without departing from the scope thereof. The scope of the present invention is limited only by the appended claims.

Claims

1. A hybrid load-sensing electro-hydraulic system, characterized in that: It includes a battery, a first inverter, a second inverter, a prime mover, a load-sensitive pump, a dual-power actuator and a first hydraulic actuator. The dual-power actuator includes a second hydraulic actuator and a load-balancing actuator connected in parallel. The battery is connected to the prime mover through the first inverter and to the load-balancing actuator through the second inverter. The prime mover is connected to the load-sensitive pump. The load-sensitive pump is connected to the first hydraulic actuator through a first multi-way valve and to the second hydraulic actuator through a second multi-way valve. A first pressure sensor and a second pressure sensor are respectively provided at the oil inlet and the oil outlet of the second hydraulic actuator. The control device is respectively connected to the first pressure sensor, the second pressure sensor, the third pressure sensor, the motor of the load balancing actuator, and an oil control component in the prime mover and the load sensitive pump. The control device first determines the mode of the dual-power actuator according to the pressures detected by the first pressure sensor and the second pressure sensor and the received action signal, and obtains the load pressure p1 of the second hydraulic actuator according to the pressures detected by the first pressure sensor and the second pressure sensor and the determined mode. According to the action signal, the load pressure p1 and the maximum load pressure p2 of the first hydraulic actuator detected by the third pressure sensor, the oil control component and the motor are respectively controlled. The oil control component adjusts the amount of oil output by the load sensitive pump, and the motor adjusts the size and direction of the force or torque output by the load balancing actuator, so that the load balancing actuator can recover the throttling loss caused by the load difference of each actuator and the potential energy generated in the process of the dual-power actuator driving the load to the battery.

2. The hybrid load-sensing electro-hydraulic system according to claim 1, characterized in that: When there is only one first hydraulic actuator, the third pressure sensor is provided at the load feedback port of the first multi-way valve, and the maximum load pressure p2 is the load pressure of the first hydraulic actuator; When there are multiple first hydraulic actuators, for every two adjacent first hydraulic actuators in sequence, a first shuttle valve is provided between the two adjacent first hydraulic actuators, the first oil inlet of the first shuttle valve is connected to the load feedback port of the first multi-way valve corresponding to one of the first hydraulic actuators, the second oil inlet is connected to the oil outlet of the next first shuttle valve, and the oil outlet is connected to the second oil inlet of the previous first shuttle valve, wherein only the oil outlet of the first first shuttle valve is connected to the third pressure sensor, and only the second oil inlet of the last first shuttle valve is connected to the load feedback port of the first multi-way valve corresponding to another first hydraulic actuator, and the maximum load pressure p2 is the maximum load pressure among the multiple first hydraulic actuators.

3. The hybrid load-sensing electro-hydraulic system according to claim 2, characterized in that: When there is only one first hydraulic actuator, a second pressure compensating valve is further provided between the second multi-way valve and the load-sensitive pump, and a load feedback port of the second multi-way valve is connected to a pilot port of the second pressure compensating valve. A first pressure compensating valve is further provided between the first multi-way valve and the load-sensitive pump, and a load feedback port of the first multi-way valve is connected to a pilot port of the first pressure compensating valve. It also includes a second shuttle valve, the first oil inlet of the second shuttle valve is connected to the load feedback port of the second multi-way valve, the second oil inlet is connected to the load feedback port of the first multi-way valve, the oil outlet of the second shuttle valve is connected to the load sensitive pump or the fourth pressure sensor, and the oil outlet of the second shuttle valve screens out the maximum load pressure of the dual-power actuator and the first hydraulic actuator; in the case where the load difference exceeds the maximum balancing power of the load balancing actuator, resulting in an abnormal working state of the system, the control device adjusts the speed of the prime mover according to the pressure detected by the fourth pressure sensor, or the load sensitive pump adjusts its displacement by itself, so that the prime mover drives the load sensitive pump to provide a corresponding amount of oil, so that the system pressure output by the load sensitive pump matches the maximum load pressure of the dual-power actuator and the first hydraulic actuator, and the first pressure compensation valve or the second pressure compensation valve is used to adjust the pressure provided to the first hydraulic actuator or the second hydraulic actuator; When there are multiple first hydraulic actuators, a second pressure compensating valve is further provided between the second multi-way valve and the load-sensitive pump, and a load feedback port of the second multi-way valve is connected to a pilot port of the second pressure compensating valve. For each first hydraulic actuator, a corresponding first pressure compensating valve is further provided between the first multi-way valve corresponding to the first hydraulic actuator and the load-sensitive pump, and a load feedback port of each first multi-way valve is connected to a pilot port of the corresponding first pressure compensating valve. It also includes a second shuttle valve, the first oil inlet of the second shuttle valve is connected to the load feedback port of the second multi-way valve, and the second oil inlet is connected to the oil outlet of the first shuttle valve; the oil outlet of the second shuttle valve is connected to the load sensitive pump or the fourth pressure sensor, and the oil outlet of the second shuttle valve screens out the maximum load pressure of the dual-power actuator and the multiple first hydraulic actuators; when the load difference exceeds the maximum balancing power of the load balancing actuator, resulting in an abnormal working state of the system, the control device adjusts the speed of the prime mover according to the pressure detected by the fourth pressure sensor, or the load sensitive pump adjusts its displacement by itself, so that the prime mover drives the load sensitive pump to provide a corresponding amount of oil, so that the system pressure output by the load sensitive pump matches the maximum load pressure of the dual-power actuator and the multiple first hydraulic actuators, and each of the first pressure compensation valves or the second pressure compensation valves is used to adjust the pressure provided to the corresponding first hydraulic actuator or second hydraulic actuator.

4. The hybrid load-sensing electro-hydraulic system according to claim 1, characterized in that: The dual-power actuator is a dual-power cylinder composed of a hydraulic cylinder and an electric cylinder in parallel, or a hydraulic cylinder and an electrostatic hydraulic actuator in parallel, or a dual-power motor composed of a hydraulic motor and an electric motor in parallel; the load balancing actuator is an electric cylinder, an electrostatic hydraulic actuator, or an electric motor.

5. The hybrid load-sensing electro-hydraulic system according to claim 1, characterized in that: The prime mover is an electric motor or an engine; the first hydraulic actuator is a hydraulic cylinder or a hydraulic motor.

6. The hybrid load-sensing electro-hydraulic system according to claim 1, characterized in that: The oil outlet of the load-sensing pump is connected to the first oil inlet of the corresponding first multi-way valve, the oil outlet of the first multi-way valve is connected to the oil inlet of the first hydraulic actuator, and the oil outlet of the first hydraulic actuator is connected to the second oil inlet of the first multi-way valve; The oil outlet of the load-sensing pump is also connected to the oil inlet of the corresponding second multi-way valve, the oil outlet of the second multi-way valve is connected to the oil inlet of the corresponding second hydraulic actuator, and the oil outlet of the second hydraulic actuator is connected to the second oil inlet of the second multi-way valve.

7. A control method for a hybrid load-sensing electro-hydraulic system according to any one of claims 1 to 6, characterized in that: The control device performs system control according to the following steps: Step S100, after receiving the action signal, judging whether the system is in a dual-power actuator single action state or a dual-power actuator and a first hydraulic actuator combined action state according to the action signal, and sending the action signal to the multi-way valves corresponding to the dual-power actuator and the first hydraulic actuator, so that each multi-way valve is switched, thereby switching the system to the corresponding action state; Step S200, calculating the force or torque of the second hydraulic actuator according to the two-chamber pressures of the second hydraulic actuator in the dual-power actuator detected by the first pressure sensor and the second pressure sensor, determining the direction of the current load force or torque on the dual-power actuator according to the calculated force or torque of the second hydraulic actuator and the force or torque currently output by the load balancing actuator in the dual-power actuator, determining the movement direction that the dual-power actuator will enter after the system switches to the corresponding action state according to the action signal, and judging whether the dual-power actuator is in impedance mode or in overrunning mode according to the direction of the current load force or torque and the movement direction; Step S300, dividing the system working condition based on the action state and the mode, and controlling the oil control component and the motor according to the divided system working condition, the load pressure p1 of the second hydraulic actuator in the dual-power actuator, and the maximum load pressure p2 of the first hydraulic actuator, so that the oil control component adjusts the amount of oil output by the load-sensitive pump, and the motor adjusts the size and direction of the force or torque output by the load balancing actuator, so that the load balancing actuator can recover the throttling loss caused by the load difference of each actuator and the potential energy generated in the process of the dual-power actuator driving the load to the battery.

8. The control method according to claim 7, characterized in that: In step S200, judging whether the dual-power actuator is in the impedance mode or the overrunning mode according to the direction of the load force or torque and the direction of movement includes: when the direction of the load force or torque is opposite to the direction of movement, the dual-power actuator is in the impedance mode; when the direction of the load force or torque is the same as the direction of movement, the dual-power actuator is in the overrunning mode; Before the step S300, it also includes: obtaining the load pressure p1 of the second hydraulic actuator according to the pressure detected by the first pressure sensor and the second pressure sensor and the determined mode, and the load pressure p1 is the oil inlet end pressure of the dual-power actuator; when the dual-power actuator is a dual-power cylinder, if the mode is an overrunning mode, the load pressure p1 is the pressure detected by the corresponding pressure sensor connected to the rodless chamber in the second hydraulic actuator; if the mode is an impedance mode, the load pressure p1 is the pressure detected by the corresponding pressure sensor connected to the rod chamber in the second hydraulic actuator.

9. The control method according to claim 7 or 8, characterized in that: The step S300 specifically includes: When the system is in the working condition of: when the dual-power actuator acts alone in the impedance mode, the motor of the load-balancing actuator cannot work in the generator mode, and the motor of the load-balancing actuator is controlled not to act. Under the premise that the second pressure compensation valve corresponding to the dual-power actuator does not act, the control device adjusts the speed of the prime mover, or the load-sensitive pump adjusts its displacement automatically, so that the prime mover drives the load-sensitive pump to provide a corresponding amount of oil. At this time, the second hydraulic actuator bears all the load and drives the load-balancing actuator to follow the movement; When the system is in the working condition of: when the dual-power actuator acts alone in the overrunning mode, the motor is controlled to drive the load-balancing actuator to output a force or torque of a corresponding magnitude opposite to the load direction, so that the load-balancing actuator bears all the load, and the load-balancing actuator works in the generator mode, and under the premise that the second pressure compensation valve corresponding to the dual-power actuator does not act, the control device adjusts the speed of the prime mover, or the load-sensitive pump adjusts its displacement automatically, so that the prime mover drives the load-sensitive pump to provide a corresponding amount of oil, thereby realizing that the second hydraulic actuator follows the movement of the load-balancing actuator; When the system working condition is: when the dual-power actuator operates in impedance mode in combination with the first hydraulic actuator, the load pressure p1 is compared with the maximum load pressure p2 of the first hydraulic actuator detected by the third pressure sensor: If p1>p2, then under the premise that the second pressure compensation valve corresponding to the dual-power actuator does not act, the motor is controlled to drive the load-balancing actuator to output a force or torque of a corresponding magnitude that is the same as the movement direction of the second hydraulic actuator and opposite to the load direction. The difference between p1 and p2 is assumed to be the first pressure. The force or torque output by the load-balancing actuator is equal to the force or torque output by the second hydraulic actuator when the load applies the first pressure to the second hydraulic actuator. The control device adjusts the speed of the prime mover, or the load-sensitive pump adjusts its displacement automatically, so that the prime mover drives the load-sensitive pump to output a corresponding amount of oil, so that the system pressure output by the load-sensitive pump matches the maximum load pressure p2. At this time, the load-balancing actuator works in the energy consumption mode; If p1 < p2, on the premise that the second pressure compensation valve corresponding to the dual-power actuator does not act, control the motor to drive the load balance actuator to output a corresponding magnitude of force or torque in the direction opposite to the movement direction of the second hydraulic actuator and the same as the load direction. Let the difference between p2 and p1 be the second pressure. The force or torque output by the load balance actuator is equal to the force or torque output by the second hydraulic actuator when the load applies the second pressure to the second hydraulic actuator. The control device adjusts the speed of the prime mover, or the load-sensitive pump automatically adjusts its displacement, so that the prime mover drives the load-sensitive pump to provide a corresponding amount of oil, so that the system pressure output by the load-sensitive pump matches the maximum load pressure p2. At this time, the load balance actuator operates in the generator mode; When the system working condition is that the dual-power actuator acts in combination with the first hydraulic actuator in an override mode, the control device adjusts the speed of the prime mover, or the load-sensitive pump automatically adjusts its displacement, so that the prime mover drives the load-sensitive pump to output a corresponding amount of oil, so that the system pressure output by the load-sensitive pump matches the maximum load pressure p2. On the premise that the second pressure compensation valve corresponding to the dual-power actuator does not act, the motor drives the load balance actuator to output a corresponding magnitude of force or torque in the direction opposite to the movement direction of the second hydraulic actuator and the opposite to the load direction. The force or torque output by the load balance actuator is equal to the sum of the force or torque output by the second hydraulic actuator when the load applies the load pressure p1 to the second hydraulic actuator and the force or torque output by the second hydraulic actuator when the load applies p2 to the second hydraulic actuator. At this time, the load balance actuator operates in the generator mode.

10. The control method according to claim 7, characterized in that: In the step S100, when it is determined according to the action signal that the dual-power actuator does not act, the control device adjusts the speed of the prime mover, or the load-sensitive pump automatically adjusts its displacement, so that the prime mover drives the load-sensitive pump to provide a corresponding amount of oil, so that the system pressure output by the load-sensitive pump matches the maximum load pressure in the dual-power actuator and the first hydraulic actuator. Each first pressure compensation valve or second pressure compensation valve adjusts the pressure provided to the corresponding first hydraulic actuator or second hydraulic actuator.

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