Battery overcharge prevention device and method for multi-shaft hydraulic system

Abstract

The invention discloses a battery overcharge prevention device and method for a multi-shaft hydraulic system. The battery overcharge prevention device comprises a first shaft control loop, a second shaft control loop, a third shaft control loop, a battery and an overflow valve. When the first hydraulic cylinder descends under the action of a load, the first hydraulic pump and the second hydraulic pump operate as hydraulic motors, and the first executing mechanism converts mechanical energy generated by the first hydraulic pump and the second hydraulic pump into electric energy to charge a battery; or when the charge state of the battery is larger than or equal to the first threshold value, the first executing mechanism converts the electric energy stored in the battery into mechanical energy to drive the third hydraulic pump and / or the fourth hydraulic pump. According to the battery overcharge prevention device, recovery energy exceeding the battery capacity can serve as heat energy to be consumed through the overflow valve by means of devices in the hydraulic loop, the additional installation cost for preventing battery overcharge is reduced, and stable operation of a hydraulic system can be protected.

Description

Technical Field

[0001] This invention relates to the field of hydraulic system technology, and in particular to a device and method for preventing battery overcharging in a multi-axis hydraulic system. Background Technology

[0002] Electric mobile machinery is gaining widespread attention for reducing carbon dioxide emissions and lowering system lifecycle costs, offering the best solution for the future of construction machinery. In response to market demand, many manufacturers are actively promoting the electrification of existing diesel excavators.

[0003] In electric excavators, the application of electric motors requires modifications to the existing hydraulic system. Directly replacing the diesel engine with an electric motor of equal power would face installation space limitations, and would increase the size and cost of the required inverter. Furthermore, considering the electric motor's primary operating range, reducing its size and designing it for high-speed operation is more advantageous. Therefore, a distributed system is needed—that is, each cylinder connected to an independent small pump—rather than the traditional centralized system supplied by a main pump.

[0004] Hydraulic pumps consume energy by transporting fluid from a low-pressure area to a high-pressure area, while the used fluid flows back from the high-pressure area to the low-pressure area, thus enabling the hydraulic pump to function as a hydraulic motor. This allows the electric motor to operate as a generator, directly converting hydraulic energy into electrical energy, which is then stored in a battery via an inverter—a process known as energy recovery.

[0005] However, if additional energy is supplied to the battery through energy recovery when it is already fully charged, it may lead to overcharging. For example, when the telescopic boom cylinder is extended and the battery is fully charged, the operator may need to actuate the cylinder (e.g., lowering the telescopic boom under load). In this case, the descent itself generates regenerative energy. Without a proper energy handling mechanism, the recovered energy may be forcibly injected into the battery, increasing the risk of overcharging. Battery overcharging is extremely dangerous, potentially causing thermal runaway, battery swelling, or even, in extreme cases, explosion. Lithium-ion batteries face particularly significant risks in this regard.

[0006] In electric vehicles, regenerative braking can be automatically deactivated when the battery reaches its charging limit. At this point, excess regenerative energy is converted into heat and released via a conventional mechanical friction brake, rather than being stored in the battery. However, directly applying this method to a hydraulic linear drive system is not suitable. Summary of the Invention

[0007] This invention provides a device and method for preventing battery overcharging in a multi-axis hydraulic system. When the recoverable energy of the hydraulic system exceeds the capacity of the battery, the oil is transferred to the relief valve through the first hydraulic pump and / or the second hydraulic pump. The relief valve then returns the oil to the oil tank. Overcharged energy can be recovered by installing the original components of the hydraulic system, which not only reduces installation costs and space, but also ensures the safe and stable operation of the hydraulic system.

[0008] According to a first aspect of the present invention, an anti-overcharge device for a multi-axis hydraulic system is provided, comprising: a first axis control circuit, a second axis control circuit, a third axis control circuit, a battery, and an overflow valve; The first axis control circuit includes a first hydraulic cylinder, a first hydraulic pump, a second hydraulic pump, and a first actuator; a first end of the first hydraulic pump is connected to the first hydraulic cylinder, and a second end of the first hydraulic pump is connected to the first end of the second hydraulic pump; a second end of the second hydraulic pump is connected to the first end of the first actuator; and a second end of the first actuator is connected to the first output end of the battery. The second axis control circuit includes a second hydraulic cylinder, a third hydraulic pump, and a second actuator; the first end of the third hydraulic pump is connected to the second hydraulic cylinder, and the second end of the third hydraulic pump is connected to the first end of the second actuator; the second end of the second actuator is connected to the second output end of the battery. The third axis control circuit includes a third hydraulic cylinder, a fourth hydraulic pump, and a third actuator; the first end of the fourth hydraulic pump is connected to the third hydraulic cylinder, and the second end of the fourth hydraulic pump is connected to the first end of the third actuator; the second end of the third actuator is connected to the third output end of the battery. When the first hydraulic cylinder descends under the load, the first hydraulic pump and the second hydraulic pump operate as hydraulic motors, and the first actuator converts the mechanical energy generated by the first hydraulic pump and the second hydraulic pump into electrical energy to charge the battery. Alternatively, when the state of charge of the battery is greater than or equal to the first threshold, the first actuator converts the electrical energy stored in the battery into mechanical energy to drive the third hydraulic pump and / or the fourth hydraulic pump. The output end of the overflow valve is connected to the oil tank. The overflow valve is used to return the oil from the third hydraulic pump and / or the fourth hydraulic pump to the oil tank when the state of charge of the battery is greater than or equal to the first threshold.

[0009] Optionally, a fifth hydraulic pump and a fourth actuator may also be included; The first end of the fifth hydraulic pump is connected to the battery, and the second output end of the fifth hydraulic pump is connected to the pre-charged hydraulic line. The fifth hydraulic pump is used to transmit oil to the first hydraulic cylinder, the second hydraulic cylinder and / or the third hydraulic cylinder through the pre-charged hydraulic line; The first end of the fourth actuator is connected to the fourth output end of the battery, and the second end of the fourth actuator is connected to the first end of the fifth hydraulic pump. The fourth actuator is used to convert the electrical energy of the battery into mechanical energy to drive the fifth hydraulic pump.

[0010] Optionally, the second axis control loop further includes a second control valve, and the third axis control loop further includes a third control valve; The first end of the second control valve is connected to the third hydraulic pump, the second end of the second control valve is connected to the second hydraulic cylinder, and the third end of the second control valve is connected to the relief valve. The second control valve is used to receive oil from the third hydraulic pump and transmit the oil to the second hydraulic cylinder or the relief valve; The first end of the third control valve is connected to the fourth hydraulic pump, the second end of the third control valve is connected to the third hydraulic cylinder, and the third end of the third control valve is connected to the relief valve. The third control valve is used to receive the oil from the fourth hydraulic pump and transmit the oil to the third hydraulic cylinder or the relief valve.

[0011] According to a second aspect of the present invention, a method for preventing battery overcharging in a multi-axis hydraulic system is provided, applicable to the battery overcharging prevention device of the multi-axis hydraulic system described in any of the above embodiments, the method comprising: Acquire the battery's state of charge and the operating status of the second and third hydraulic cylinders; When the state of charge is greater than or equal to the second threshold, the conduction direction of the second control valve and the third control valve is determined according to the operating state.

[0012] Optionally, determining the conduction direction of the second and third control valves based on the operating state includes: When both the second hydraulic cylinder and the third hydraulic cylinder are in an idle state, the second control valve and the third control valve are simultaneously opened to allow the oil to flow to the relief valve.

[0013] Optionally, when both the second hydraulic cylinder and the third hydraulic cylinder are in an idle state, simultaneously controlling the second control valve and the third control valve to open so that the oil flows to the relief valve, the method further includes: Obtain the recoverable power of the first actuator; When the power consumption of the third and fourth hydraulic pumps is greater than or equal to the recoverable power, the transmission speed of the oil is controlled by adjusting the rotational speed of the second and third actuators. When the maximum power consumption of the third and fourth hydraulic pumps is less than the recoverable power, the rotational speed of the first actuator is determined based on the maximum power consumption.

[0014] Optionally, determining the conduction direction of the second and third control valves based on the operating state includes: When both the second hydraulic cylinder and the third hydraulic cylinder are in operation, the second control valve and the third control valve are simultaneously opened so that the oil flows to the second hydraulic cylinder and the third hydraulic cylinder respectively.

[0015] Optionally, when both the second hydraulic cylinder and the third hydraulic cylinder are in operation, the second control valve and the third control valve are simultaneously opened to allow oil to flow to the second hydraulic cylinder and the third hydraulic cylinder respectively, further comprising: Obtain the total power consumption of the first hydraulic pump, the second hydraulic pump, the third hydraulic pump, and the fourth hydraulic pump; The rotational speed of the first actuator is determined based on the total power consumption.

[0016] Optionally, determining the conduction direction of the second and third control valves based on the operating state includes: When the second hydraulic cylinder or the third hydraulic cylinder is in operation, the second control valve is controlled to be connected to the second hydraulic cylinder, and the third control valve is controlled to be connected to the relief valve, or the third control valve is controlled to be connected to the third hydraulic cylinder, and the second control valve is controlled to be connected to the relief valve.

[0017] Optionally, when the second hydraulic cylinder is in operation or the third hydraulic cylinder is in operation, the second control valve is controlled to be connected to the second hydraulic cylinder, and the third control valve is controlled to be connected to the relief valve, or the third control valve is controlled to be connected to the third hydraulic cylinder, and the second control valve is controlled to be connected to the relief valve, including; Obtain the recoverable power of the first actuator; When the maximum power consumption of the first hydraulic pump, the second hydraulic pump, and the third hydraulic pump is greater than or equal to the recoverable power, or when the maximum power consumption of the first hydraulic pump, the second hydraulic pump, and the fourth hydraulic pump is greater than or equal to the recoverable power, the transmission speed of the oil is controlled by adjusting the rotation speed of the second actuator or the third actuator. When the maximum power consumption of the first hydraulic pump, the second hydraulic pump, and the third hydraulic pump is less than the recoverable power, or when the maximum power consumption of the first hydraulic pump, the second hydraulic pump, and the fourth hydraulic pump is less than the recoverable power, the rotational speed of the third actuator or the second actuator is determined based on the difference between the recoverable power and the maximum power consumption, and the rotational speed of the first actuator is determined based on the maximum power consumption.

[0018] This invention discloses a battery overcharge prevention device and method for a multi-axis hydraulic system, comprising: a first axis control circuit, a second axis control circuit, a third axis control circuit, a battery, and an overflow valve; the first axis control circuit includes a first hydraulic cylinder, a first hydraulic pump, a second hydraulic pump, and a first actuator; a first end of the first hydraulic pump is connected to the first hydraulic cylinder, and a second end of the first hydraulic pump is connected to the first end of the second hydraulic pump; a second end of the second hydraulic pump is connected to the first end of the first actuator; a second end of the first actuator is connected to the first output end of the battery; the second axis control circuit includes a second hydraulic cylinder, a third hydraulic pump, and a second actuator; a first end of the third hydraulic pump is connected to the second hydraulic cylinder, and a second end of the third hydraulic pump is connected to the first end of the second actuator; a second end of the second actuator is connected to the second output end of the battery; the third axis control circuit... The control circuit includes a third hydraulic cylinder, a fourth hydraulic pump, and a third actuator; the first end of the fourth hydraulic pump is connected to the third hydraulic cylinder, and the second end of the fourth hydraulic pump is connected to the first end of the third actuator; the second end of the third actuator is connected to the third output end of the battery; when the first hydraulic cylinder descends under load, the first and second hydraulic pumps operate as hydraulic motors, and the first actuator converts the mechanical energy generated by the first and second hydraulic pumps into electrical energy to charge the battery; or when the battery's state of charge is greater than or equal to a first threshold, the first actuator converts the electrical energy stored in the battery into mechanical energy to drive the third and / or fourth hydraulic pumps; the output end of the relief valve is connected to the oil tank, and the relief valve is used to return the oil from the third and / or fourth hydraulic pumps to the oil tank when the battery's state of charge is greater than or equal to the first threshold. The overcharge protection device for a multi-axis hydraulic system provided by this invention, when the recoverable energy of the hydraulic system exceeds the capacity of the battery, transmits oil to the relief valve through the first hydraulic pump and / or the second hydraulic pump. The relief valve then returns the oil to the oil tank. Overcharged energy can be recovered by installing the original components of the hydraulic system, which not only reduces installation costs and space, but also ensures the safe and stable operation of the hydraulic system.

[0019] It should be understood that the description in this section is not intended to identify key or essential features of the embodiments of the present invention, nor is it intended to limit the scope of the invention. Other features of the invention will become readily apparent from the following description. Attached Figure Description

[0020] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0021] Figure 1 This is a schematic diagram of a battery overcharge prevention device for a multi-axis hydraulic system provided in an embodiment of the present invention; Figure 2 This is a schematic diagram of the structure of an anti-battery overcharge device for another multi-axis hydraulic system provided in an embodiment of the present invention; Figure 3 This is a schematic diagram of the structure of an anti-battery overcharge device for another multi-axis hydraulic system provided in an embodiment of the present invention; Figure 4 This is a schematic diagram of the structure of an anti-battery overcharge device for another multi-axis hydraulic system provided in an embodiment of the present invention; Figure 5 This is a flowchart of a method for preventing battery overcharging in a multi-axis hydraulic system provided in an embodiment of the present invention; Figure 6 This is a flowchart of a method for preventing battery overcharging in a multi-axis hydraulic system provided in an embodiment of the present invention; Figure 7 This is a flowchart of a method for preventing battery overcharging in a multi-axis hydraulic system provided in an embodiment of the present invention; Figure 8 This is a flowchart of a method for preventing battery overcharging in a multi-axis hydraulic system provided in an embodiment of the present invention; Figure 9 This is a flowchart of a method for preventing battery overcharging in a multi-axis hydraulic system provided in an embodiment of the present invention; Figure 10 This is a flowchart of a method for preventing battery overcharging in a multi-axis hydraulic system provided in an embodiment of the present invention; Figure 11 This is a flowchart of a method for preventing battery overcharging in a multi-axis hydraulic system provided in an embodiment of the present invention. Detailed Implementation

[0022] To enable those skilled in the art to better understand the present invention, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of the present invention.

[0023] It should be noted that the terms "first," "second," etc., in the specification, claims, and accompanying drawings of this invention are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments of the invention described herein can be implemented in orders other than those illustrated or described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover a non-exclusive inclusion; for example, a process, method, system, product, or apparatus that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatus.

[0024] It should be understood that the various forms of processes shown above can be used, with steps reordered, added, or deleted. For example, the steps described in this invention can be executed in parallel, sequentially, or in different orders, as long as the desired result of the technical solution of this invention can be achieved, and this is not limited herein.

[0025] Figure 1 This is a schematic diagram of a battery overcharge prevention device for a multi-axis hydraulic system provided in an embodiment of the present invention. (Refer to...) Figure 1 The battery overcharge prevention device for a multi-axis hydraulic system provided in this embodiment of the invention includes: a first axis control circuit 1, a second axis control circuit 2, a third axis control circuit 3, a battery 4, and an overflow valve 5; The first axis control circuit 1 includes a first hydraulic cylinder 101, a first hydraulic pump 102, a second hydraulic pump 103, and a first actuator 104; the first end of the first hydraulic pump 102 is connected to the first hydraulic cylinder 101, and the second end of the first hydraulic pump 102 is connected to the first end of the second hydraulic pump 103; the second end of the second hydraulic pump 103 is connected to the first end of the first actuator 104; the second end of the first actuator 104 is connected to the first output end of the battery 4. The second axis control circuit 2 includes a second hydraulic cylinder 201, a third hydraulic pump 202, and a second actuator 203; the first end of the third hydraulic pump 202 is connected to the second hydraulic cylinder 201, and the second end of the third hydraulic pump 202 is connected to the first end of the second actuator 203; the second end of the second actuator 203 is connected to the second output end of the battery 4. The third axis control circuit 3 includes a third hydraulic cylinder 301, a fourth hydraulic pump 302, and a third actuator 303; the first end of the fourth hydraulic pump 302 is connected to the third hydraulic cylinder 301, and the second end of the fourth hydraulic pump 302 is connected to the first end of the third actuator 303; the second end of the third actuator 303 is connected to the third output end of the battery 4. When the first hydraulic cylinder 101 is under load ( Figure 1When the battery 4 is lowered by the action of the first hydraulic pump 102 and the second hydraulic pump 103 (not shown in the figure), the first hydraulic pump 102 and the second hydraulic pump 103 operate as hydraulic motors, and the first actuator 104 converts the mechanical energy generated by the first hydraulic pump 102 and the second hydraulic pump 103 into electrical energy to charge the battery 4. Or when the state of charge of battery 4 is greater than or equal to the first threshold, the first actuator 104 converts the electrical energy stored in battery 4 into mechanical energy to drive the third hydraulic pump 202 and / or the fourth hydraulic pump 302. The output end of the overflow valve 5 is connected to the oil tank 6. The overflow valve 5 is used to return the oil from the third hydraulic pump 202 and / or the fourth hydraulic pump 302 to the oil tank 6 when the state of charge of the battery 4 is greater than or equal to the first threshold.

[0026] Specifically, the first axis control circuit 1 includes a first hydraulic cylinder 101, a first hydraulic pump 102, a second hydraulic pump 103, and a first actuator 104. In the hydraulic system of the hydraulic excavator, the first hydraulic cylinder 101 typically moves along the direction of gravity and is configured as a closed-loop system. When the first hydraulic cylinder 101 extends, oil flows to it. When the first hydraulic cylinder 101 retracts, the cylinder retraction flow of the first hydraulic cylinder 101 is divided into two paths, Q1a and Q1b. Among them, the flow rate Q1a is controlled by the second hydraulic pump 103. Flow 03 flows out and eventually returns to the pre-charged hydraulic line 7; flow Q1b flows out from the first hydraulic pump 102 and eventually flows to the cylinder head side of the first hydraulic cylinder 101. Under normal circumstances, since the first hydraulic cylinder 101 needs to support all mechanical equipment against gravity, the pressure p1a is in a high-pressure state, while the pressure of the pre-charged hydraulic line 7 is usually maintained in a low-pressure state. Furthermore, since the first shaft control circuit 1 adopts a closed-loop configuration, a certain pressure of the first shaft control circuit 1 always maintains the pressure pc of the pre-charged hydraulic line 7. During the retraction process of the first hydraulic cylinder 101, the pressure p1b is always equal to the pressure pc of the pre-charged hydraulic line 7. During this process, the flow rate Q1a of the first hydraulic fluid flows from the second hydraulic pump 103 (where pressure p1a is in the high-pressure zone) to the pre-charge hydraulic line 7 (where pressure p1a is in the low-pressure zone); the flow rate Q1b of the second hydraulic fluid flows from the first hydraulic pump 101 (where pressure p1b is in the low-pressure zone) to the first hydraulic cylinder 101 (where pressure p1b is in the low-pressure zone) to the first hydraulic cylinder 101 (where pressure p1b is in the even lower-pressure zone, to enable equipment operation). Therefore, both the flow rates Q1a and Q1b transport the hydraulic fluid from the high-pressure zone to the low-pressure zone, thus enabling the first hydraulic pump 102 and the second hydraulic pump 103 to function as hydraulic motors. A hydraulic motor is a device that converts hydraulic energy into mechanical energy. At this time, the theoretical recoverable power is: P recup =Q1a×(p1a-pc)+Q1b×(p1a-p1b);where, P recupThe system is designed to recover energy, with Q1a being the flow rate of the second hydraulic pump, Q1b being the flow rate of the first hydraulic pump, p1a being the left-side pressure value of the second hydraulic pump, and p1b being the right-side pressure value of the first hydraulic pump. The second control circuit 2 includes a second hydraulic cylinder 201, a third hydraulic pump 202, and a second actuator 203. The second actuator 203 is used to convert the electrical energy of the battery 4 into mechanical energy to drive the third hydraulic pump 202 to move and transmit oil to the second hydraulic cylinder 201. The third axis control circuit 3 includes a third hydraulic cylinder 301, a fourth hydraulic pump 302, and a third actuator 303; the third actuator 303 is used to convert the electrical energy of the battery 4 into mechanical energy to drive the fourth hydraulic pump 302 to move and transmit oil to the third hydraulic cylinder 301. Battery 4 also includes a battery management system ( Figure 1 (Not shown in the image), the battery management system is used to monitor the state of charge of battery 4, which indicates the amount of electrical energy stored. When the first hydraulic cylinder 101 descends under load, the system can recover energy through the first actuator 104. The principle of energy recovery is as follows: Since the oil flow rates Q1a and Q1b both transport the oil from the high-pressure area to the low-pressure area, the first hydraulic pump 102 and the second hydraulic pump 103 function as hydraulic motors. As the oil flows from the high-pressure area to the low-pressure area, a large amount of hydraulic energy is generated. The hydraulic motor can convert the hydraulic pump into mechanical energy, thereby driving the first actuator 104 to move. The first actuator 104 then operates as a generator, converting mechanical energy into electrical energy. The frequency converter module 8 includes a first frequency converter unit 81, a second frequency converter unit 82, a third frequency converter unit 83, and a fourth frequency converter unit 84. The first frequency converter unit 81 is connected to the first actuator 104 to enable the first actuator 104 to work as a generator. The electrical energy generated by the first actuator 104 is stored in the battery 4 through the power distribution unit 11, thereby realizing energy recovery. The electrical energy stored in battery 4 is distributed to inverter module 8 through power distribution unit 9, and then distributed to the actuators of each axle through inverter module 8; or, inverter module 8 feeds back the electrical energy generated by the first actuator 104 to battery 4 for storage through power distribution unit 9.

[0027] When the state of charge of battery 4 is greater than or equal to the second threshold (e.g., 99%), the first actuator 104 operates as an electric motor, converting the excess electrical energy of battery 4 into mechanical energy and driving the third hydraulic pump 202 and / or the fourth hydraulic pump 302 to deliver oil from the third hydraulic pump 202 and / or the fourth hydraulic pump 302 to the relief valve 5. The output end of the overflow valve 5 is connected to the oil tank 6. The overflow valve 5 is used to return the oil from the third hydraulic pump 202 and / or the fourth hydraulic pump 302 to the oil tank 6 when the state of charge of the battery 4 is greater than or equal to the second threshold, thereby preventing the risk of overcharging of the battery 4.

[0028] The battery overcharge protection device for a multi-axis hydraulic system provided in this invention, when the recoverable energy of the hydraulic system exceeds the capacity of the battery, transmits oil to the relief valve through the first hydraulic pump and / or the second hydraulic pump. The relief valve then returns the oil to the oil tank. Overcharged energy can be recovered by installing the original components of the hydraulic system, which not only reduces installation costs and space, but also ensures the safe and stable operation of the hydraulic system.

[0029] Optional, Figure 2 This is a schematic diagram of another battery overcharge prevention device for a multi-axis hydraulic system provided in an embodiment of the present invention. (Refer to...) Figure 2 The battery overcharge prevention device for the multi-axis hydraulic system provided in this embodiment of the invention further includes a fifth hydraulic pump 10 and a fourth actuator 11; The first end of the fifth hydraulic pump 10 is connected to the battery 4, and the second output end of the fifth hydraulic pump 10 is connected to the pre-charged hydraulic line 7. The fifth hydraulic pump 10 is used to transmit oil to the first hydraulic cylinder 103, the second hydraulic cylinder 202 and / or the third hydraulic cylinder 302 via the pre-charged hydraulic line 7; The first end of the fourth actuator 11 is connected to the fourth output end of the battery 4, and the second end of the fourth actuator 11 is connected to the first end of the fifth hydraulic pump 10; The fourth actuator 11 is used to convert the electrical energy of the battery 4 into mechanical energy to drive the fifth hydraulic pump 10.

[0030] Specifically, the battery overcharge prevention device of the multi-axis hydraulic system provided in this embodiment of the invention further includes a fifth hydraulic pump 10 (which will serve as the main hydraulic pump to supply oil to the entire hydraulic system) and a fourth actuator 11 (which will serve as the main power source to provide power for the flow of oil in the entire hydraulic system); the fourth actuator 11 converts the electrical energy of the battery 4 into mechanical energy to provide power to the fifth hydraulic pump 10, and the fifth hydraulic pump 10 distributes the oil to the hydraulic pumps of each control circuit through the pre-charged hydraulic line 7 to achieve normal oil delivery.

[0031] Optional, Figure 3 This is a schematic diagram of another battery overcharge prevention device for a multi-axis hydraulic system provided in an embodiment of the present invention. (Refer to...) Figure 3 The second axis control loop 2 also includes a second control valve 204, and the third axis control loop 3 also includes a third control valve 304; The first end of the second control valve 204 is connected to the third hydraulic pump 202, the second end of the second control valve 204 is connected to the second hydraulic cylinder 201, and the third end of the second control valve 204 is connected to the relief valve 5. The second control valve 204 is used to receive oil from the third hydraulic pump 202 and transmit the oil to the second hydraulic cylinder 201 or the relief valve 5. The first end of the third control valve 304 is connected to the fourth hydraulic pump 302, the second end of the third control valve 304 is connected to the third hydraulic cylinder 301, and the third end of the third control valve 304 is connected to the relief valve 5. The third control valve 304 is used to receive oil from the fourth hydraulic pump 302 and transmit the oil to the third hydraulic cylinder 301 or the relief valve 5.

[0032] Specifically, the second control valve 204 and the third control valve 304 are two-position three-way directional control valves. The second control valve 204 is used to transmit the oil from the third hydraulic pump 202 to the second hydraulic cylinder 201 or the relief valve 5; the third control valve 304 is used to transmit the oil from the fourth hydraulic pump 302 to the third hydraulic cylinder 301 or the relief valve 5.

[0033] Figure 4 This is a schematic diagram of another battery overcharge prevention device for a multi-axis hydraulic system provided in an embodiment of the present invention. (Refer to...) Figure 4 Optionally, the anti-overcharge device for the multi-axis hydraulic system provided in this embodiment of the invention further includes: an auxiliary valve 12, a second directional valve 13, and a third directional valve 14; the auxiliary valve 12 is used to transfer oil to the first hydraulic cylinder 101, the second directional valve 13 is used to transfer oil to the second hydraulic cylinder 201, and the third directional valve 14 is used to transfer oil to the third hydraulic cylinder 301.

[0034] Based on the same inventive concept Figure 5 This is a flowchart of a method for preventing battery overcharging in a multi-axis hydraulic system according to an embodiment of the present invention. (Refer to...) Figure 5 This invention also provides a method for preventing battery overcharging in a multi-axis hydraulic system, applicable to the battery overcharging prevention device of the multi-axis hydraulic system in any of the above embodiments. The method for preventing battery overcharging includes: S101. Obtain the state of charge of the battery and the working status of the second and third hydraulic cylinders.

[0035] Specifically, the battery's state of charge is obtained through the battery management system in the battery to display the battery's charging status in real time; the working status of the second and third hydraulic cylinders is determined, i.e., whether the second and third hydraulic cylinders are in operation or idle state.

[0036] S102. When the state of charge is greater than or equal to the second threshold, determine the conduction direction of the second control valve and the third control valve according to the working state.

[0037] Specifically, when the battery's state of charge is greater than or equal to the second threshold (e.g., 99%), it indicates that the battery is about to enter an overcharge state. In other words, the conduction direction of the second and third control valves is controlled according to the working state of the second and third hydraulic cylinders.

[0038] Based on the above embodiments, the present invention further refines the determination of the conduction direction of the second and third control valves according to the working state. Figure 6 This is a flowchart of a method for preventing battery overcharging in a multi-axis hydraulic system according to an embodiment of the present invention. (Refer to...) Figure 6 The method for preventing battery overcharging in a multi-axis hydraulic system provided in this embodiment of the invention includes: S201. Obtain the state of charge of the battery and the working status of the second and third hydraulic cylinders.

[0039] S202. When the state of charge is greater than or equal to the second threshold, determine the conduction direction of the second control valve and the third control valve according to the working state.

[0040] S203. When both the second and third hydraulic cylinders are idle, the second and third control valves are simultaneously opened to allow the oil to flow to the relief valve.

[0041] For details, please refer to Figure 4 When the battery's state of charge is greater than or equal to the second threshold, it indicates that the battery is about to be overcharged. The working status of the second and third hydraulic cylinders is obtained through the above step S202. When both the second and third hydraulic cylinders are in an idle state, the second and third control valves are activated simultaneously. At this time, the excess electrical energy of the battery is converted into mechanical energy through the second actuator 203 and the third actuator 303. Meanwhile, since the second control valve 204 and the third control valve 304 are in a conducting state, the oil can be transmitted through the second actuator 203 and the third actuator 303 to the overflow valve 5 through the second control valve 204 and the third control valve 304, and finally flow back to the oil tank 6 to avoid the risk of battery overcharging.

[0042] Based on the above embodiments, this invention further refines the method of simultaneously controlling the second and third control valves to open when both the second and third hydraulic cylinders are idle, so that the oil flows to the relief valve. Figure 7 This is a flowchart of a method for preventing battery overcharging in a multi-axis hydraulic system according to an embodiment of the present invention. (Refer to...) Figure 7 The method for preventing battery overcharging in a multi-axis hydraulic system provided in this embodiment of the invention includes: S301. Obtain the state of charge of the battery and the working status of the second and third hydraulic cylinders.

[0043] S302. When the state of charge is greater than or equal to the second threshold, determine the conduction direction of the second control valve and the third control valve according to the working state.

[0044] S303. When both the second and third hydraulic cylinders are idle, the second and third control valves are simultaneously opened to allow the oil to flow to the relief valve.

[0045] S304. Obtain the recoverable power of the first actuator.

[0046] Specifically, through P recup =Q1a×(p1a-pc)+Q1b×(p1a-p1b)Calculate the recoverable power of the first actuator.

[0047] S305. When the power consumption of the third and fourth hydraulic pumps is greater than or equal to the recoverable power, the transmission speed of the oil is controlled by adjusting the rotational speed of the second and third actuators.

[0048] Specifically, when the power consumed by the third and fourth hydraulic pumps (i.e., the power that the third and fourth hydraulic pumps can consume) is greater than or equal to the recoverable power, meaning that the recovered energy can be completely consumed through the operation of the third and fourth hydraulic pumps, the transmission speed of the oil is adjusted by regulating the rotational speed of the second and third actuators; the rotational speeds of the second and third actuators are calculated using the formula: P cons =n 2c ×D 1c ×(pr-pc)+n 2d ×D 1d ×(pr-pc)+ n 2a ×D 1a × (pc-pT). Where P cons For power consumption, n 2c For the rotational speed of the second actuator, D 1c Here, pr is the displacement of the third hydraulic pump, pr is the pressure reduction pressure of the relief valve, pc is the pressure of the pre-charge hydraulic line 7, and n is the pressure of the third hydraulic pump. 2d For the rotational speed of the third actuator, D 1d For the displacement of the fourth hydraulic pump, n 2a For the rotational speed of the fourth actuator, D 1a ρ is the displacement of the fifth hydraulic pump, and pT is the pressure in the oil tank.

[0049] S306. When the maximum power consumption of the third and fourth hydraulic pumps is less than the recoverable efficiency, the rotational speed of the first actuator is determined based on the maximum power consumption.

[0050] Specifically, the maximum power consumption of the third and fourth hydraulic pumps is determined by the product of the maximum flow rate and the pressure relief of each pump. Therefore, the maximum power consumption is limited. Furthermore, since the recoverable power is generated by the first actuator on the first shaft acting as a generator, the recoverable power must be kept within the maximum power consumption level of the hydraulic pumps (the third and fourth pumps). Therefore, the rotational speed of the first actuator needs to be limited based on the maximum power consumption to ensure that the recoverable power remains within the maximum power consumption level of the hydraulic pumps. The rotational speed of the first actuator is limited by: n 2b =P max.cons / D 1b.1 ×(p1a-pc)+ D 1b.2 ×(p1a-p1b), where n 2b For the rotational speed of the first actuator, P max.cons For maximum power consumption, D 1b.1 p1a is the displacement of the second hydraulic pump, p1a is the pressure value on the left side of the second hydraulic pump, and D is the displacement of the second hydraulic pump. 1b.2 p1b is the displacement of the first hydraulic pump, p1b is the pressure value on the right side of the first hydraulic pump, and pc is the pressure of the pre-charge hydraulic line 7.

[0051] Based on the above embodiments, the present invention further refines the determination of the conduction direction of the second and third control valves according to the working state. Figure 8 This is a flowchart of a method for preventing battery overcharging in a multi-axis hydraulic system according to an embodiment of the present invention. (Refer to...) Figure 8 The method for preventing battery overcharging in a multi-axis hydraulic system provided in this embodiment of the invention includes: S401, Obtain the state of charge of the battery and the working status of the second and third hydraulic cylinders.

[0052] S402. When the state of charge is greater than or equal to the second threshold, determine the conduction direction of the second control valve and the third control valve according to the working state.

[0053] S403. When both the second and third hydraulic cylinders are in operation, the second and third control valves are simultaneously opened so that the oil flows to the second and third hydraulic cylinders respectively.

[0054] Specifically, when the battery's state of charge is greater than or equal to the second threshold, it indicates that the battery is about to be overcharged. The working state of the second and third hydraulic cylinders is obtained through the above step S402. When both the second and third hydraulic cylinders are in operation, the second and third control valves are activated simultaneously. At this time, the excess electrical energy of the battery is converted into mechanical energy through the second actuator 203 and the third actuator 303. Meanwhile, since the second control valve 204 and the third control valve 304 are in the conducting state, the oil can be transmitted through the second actuator 203 and the third actuator 303 to the second hydraulic cylinder 201 and the third hydraulic cylinder 301 through the second control valve 204 and the third control valve 304 to consume the excess electrical energy (which has now been converted into excess mechanical energy) through the motion conditions.

[0055] Based on the above embodiments, this invention further refines the method of simultaneously controlling the second and third control valves to open when both the second and third hydraulic cylinders are in operation, so that oil flows to the second and third hydraulic cylinders respectively. Figure 9 This is a flowchart of a method for preventing battery overcharging in a multi-axis hydraulic system according to an embodiment of the present invention. (Refer to...) Figure 9 The method for preventing battery overcharging in a multi-axis hydraulic system provided in this embodiment of the invention includes: S501, Obtain the state of charge of the battery and the working status of the second and third hydraulic cylinders.

[0056] S502. When the state of charge is greater than or equal to the second threshold, determine the conduction direction of the second control valve and the third control valve according to the working state.

[0057] S503. When both the second and third hydraulic cylinders are in operation, the second and third control valves are simultaneously opened so that the oil flows to the second and third hydraulic cylinders respectively.

[0058] S504, Obtain the total power consumption of the first hydraulic pump, the second hydraulic pump, the third hydraulic pump, and the fourth hydraulic pump.

[0059] Specifically, when the second and third hydraulic cylinders are operating, the recoverable power is limited to the total power consumed by the second and third hydraulic cylinders, P. cons =n 2c ×D 1c ×(p2-pc)+n 2d ×D 1d ×(p3-pc)+ n 2a ×D 1a ×(pc-pT), where p2 is the upper pressure value of the third hydraulic pump and p3 is the upper pressure value of the fourth hydraulic pump.

[0060] S505. Determine the rotational speed of the first actuator based on the total power consumption.

[0061] Specifically, the rotational speed of the first actuator will be limited by: n 2b =P cons / D 1b.1 ×(p1a-pc)+ D 1b.2 ×(p1a-p1b), where P cons This represents the total power consumption.

[0062] Based on the above embodiments, the present invention further refines the determination of the conduction direction of the second and third control valves according to the working state. Figure 10 This is a flowchart of a method for preventing battery overcharging in a multi-axis hydraulic system according to an embodiment of the present invention. (Refer to...) Figure 10 The method for preventing battery overcharging in a multi-axis hydraulic system provided in this embodiment of the invention includes: S601, Obtain the state of charge of the battery and the working status of the second and third hydraulic cylinders.

[0063] S602. When the state of charge is greater than or equal to the second threshold, determine the conduction direction of the second control valve and the third control valve according to the working state.

[0064] S603. When the second hydraulic cylinder or the third hydraulic cylinder is in operation, the second control valve is controlled to be connected to the second hydraulic cylinder, and the third control valve is controlled to be connected to the relief valve, or the third control valve is controlled to be connected to the third hydraulic cylinder, and the second control valve is controlled to be connected to the relief valve.

[0065] Specifically, when the second hydraulic cylinder or the third hydraulic cylinder is in operation, for example, when the second hydraulic cylinder is in operation and the third hydraulic cylinder is in idle state, the third hydraulic pump corresponding to the second hydraulic cylinder is turned on to the second hydraulic cylinder to transfer oil to the second hydraulic cylinder, and the fourth hydraulic pump corresponding to the third hydraulic cylinder is turned on to the relief valve to transfer oil to the relief valve and return it to the oil tank; or, when the second hydraulic cylinder is in idle state and the third hydraulic cylinder is in operation, the fourth hydraulic pump corresponding to the third hydraulic cylinder is turned on to the third hydraulic cylinder to transfer oil to the third hydraulic cylinder, and the third hydraulic pump corresponding to the second hydraulic cylinder is turned on to the relief valve to transfer oil to the relief valve and return it to the oil tank.

[0066] Based on the above embodiments, the present invention further refines the method of controlling the second control valve to open to the second hydraulic cylinder and simultaneously controlling the third control valve to open to the relief valve, or controlling the third control valve to open to the third hydraulic cylinder and simultaneously controlling the second control valve to open to the relief valve, when the second hydraulic cylinder or the third hydraulic cylinder is in operation. Figure 11 This is a flowchart of a method for preventing battery overcharging in a multi-axis hydraulic system according to an embodiment of the present invention. (Refer to...) Figure 11 The method for preventing battery overcharging in a multi-axis hydraulic system provided in this embodiment of the invention includes: S701, Obtain the state of charge of the battery and the working status of the second and third hydraulic cylinders.

[0067] S702. When the state of charge is greater than or equal to the second threshold, the conduction direction of the second control valve and the third control valve shall be determined according to the working state.

[0068] S703. When the second hydraulic cylinder or the third hydraulic cylinder is in operation, the second control valve is controlled to be connected to the second hydraulic cylinder, and the third control valve is controlled to be connected to the relief valve, or the third control valve is controlled to be connected to the third hydraulic cylinder, and the second control valve is controlled to be connected to the relief valve.

[0069] S704. Obtain the recoverable power of the first actuator.

[0070] Specifically, through P recup =Q1a×(p1a-pc)+Q1b×(p1a-p1b)Calculate the recoverable power of the first actuator.

[0071] S705. When the maximum power consumption of the first hydraulic pump, the second hydraulic pump, and the third hydraulic pump is greater than or equal to the recoverable power, or when the maximum power consumption of the first hydraulic pump, the second hydraulic pump, and the fourth hydraulic pump is greater than or equal to the recoverable power, the transmission speed of the oil is controlled by adjusting the rotational speed of the second actuator or the third actuator.

[0072] Specifically, when the maximum power consumption of the first, second, and third hydraulic pumps is greater than or equal to the recoverable power (at which point the second hydraulic cylinder is running and the third hydraulic cylinder is idle), or when the maximum power consumption of the first, second, and fourth hydraulic pumps is greater than or equal to the recoverable power (at which point the second hydraulic cylinder is idle and the third hydraulic cylinder is running), the excess recoverable energy can be consumed by adjusting the second actuator corresponding to the second hydraulic cylinder or adjusting the third actuator corresponding to the third hydraulic cylinder. The power consumption is calculated as follows: P cons =n 2c ×D 1c ×(p2-pc)+n 2d ×D 1d ×(pr-pc)+ n 2a ×D 1a × (pc-pT).

[0073] S706. When the maximum power consumption of the first hydraulic pump, the second hydraulic pump, and the third hydraulic pump is less than the recoverable power, or when the maximum power consumption of the first hydraulic pump, the second hydraulic pump, and the fourth hydraulic pump is less than the recoverable power, the rotational speed of the third actuator or the second actuator shall be determined based on the difference between the recoverable power and the maximum power consumption, and the rotational speed of the first actuator shall be determined based on the maximum power consumption.

[0074] Specifically, when the maximum power consumption of the first, second, and third hydraulic pumps is less than the recoverable power (at which point the second hydraulic cylinder is running and the third hydraulic cylinder is idle), or when the maximum power consumption of the first, second, and fourth hydraulic pumps is less than the recoverable power (at which point the second hydraulic cylinder is idle and the third hydraulic cylinder is running), for example, when the second hydraulic cylinder is running and the third hydraulic cylinder is idle, the difference between the recoverable power and the maximum power consumption (i.e., excess energy) is consumed by the fourth hydraulic pump corresponding to the third hydraulic cylinder. Since the recoverable power needs to be kept within the range of the maximum power consumption of all hydraulic pumps, the rotational speed of the first actuator needs to be limited. The rotational speed of the first actuator is limited by: n 2b =P max.cons / D 1b.1 ×(p1a-pc)+ D 1b.2 ×(p1a-p1b) When the second hydraulic cylinder is idle and the third hydraulic cylinder is running, the difference between the recoverable power and the maximum power consumption (i.e., excess energy) is consumed by the third hydraulic pump corresponding to the second hydraulic cylinder. Since the recoverable power needs to be kept within the maximum power consumption range of all hydraulic pumps, the rotational speed of the first actuator needs to be limited. The rotational speed of the first actuator is limited by: n 2b =P max.cons / D 1b.1 ×(p1a-pc)+ D 1b.2 ×(p1a-p1b)

[0075] The method for preventing battery overcharging in a multi-axis hydraulic system provided in this embodiment of the invention can achieve the same technical effect as the method device for preventing battery overcharging in a multi-axis hydraulic system provided in the above-mentioned embodiments of the invention, and will not be described again here.

[0076] The specific embodiments described above do not constitute a limitation on the scope of protection of this invention. Those skilled in the art should understand that various modifications, combinations, sub-combinations, and substitutions can be made according to design requirements and other factors. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of this invention should be included within the scope of protection of this invention.

Claims

1. A battery overcharge prevention device for a multi-axis hydraulic system, characterized in that, include: First axis control circuit, second axis control circuit, third axis control circuit, battery and overflow valve; The first axis control circuit includes a first hydraulic cylinder, a first hydraulic pump, a second hydraulic pump, and a first actuator; a first end of the first hydraulic pump is connected to the first hydraulic cylinder, and a second end of the first hydraulic pump is connected to the first end of the second hydraulic pump; a second end of the second hydraulic pump is connected to the first end of the first actuator; and a second end of the first actuator is connected to the first output end of the battery. The second axis control circuit includes a second hydraulic cylinder, a third hydraulic pump, and a second actuator; the first end of the third hydraulic pump is connected to the second hydraulic cylinder, and the second end of the third hydraulic pump is connected to the first end of the second actuator; the second end of the second actuator is connected to the second output end of the battery. The third axis control circuit includes a third hydraulic cylinder, a fourth hydraulic pump, and a third actuator; the first end of the fourth hydraulic pump is connected to the third hydraulic cylinder, and the second end of the fourth hydraulic pump is connected to the first end of the third actuator; the second end of the third actuator is connected to the third output end of the battery. When the first hydraulic cylinder descends under the load, the first hydraulic pump and the second hydraulic pump operate as hydraulic motors, and the first actuator converts the mechanical energy generated by the first hydraulic pump and the second hydraulic pump into electrical energy to charge the battery. Alternatively, when the state of charge of the battery is greater than or equal to the first threshold, the first actuator converts the electrical energy stored in the battery into mechanical energy to drive the third hydraulic pump and / or the fourth hydraulic pump. The output end of the overflow valve is connected to the oil tank. The overflow valve is used to return the oil from the third hydraulic pump and / or the fourth hydraulic pump to the oil tank when the state of charge of the battery is greater than or equal to the first threshold.

2. The anti-overcharge device for a multi-axis hydraulic system according to claim 1, characterized in that, It also includes a fifth hydraulic pump and a fourth actuator; The first end of the fifth hydraulic pump is connected to the battery, and the second output end of the fifth hydraulic pump is connected to the pre-charged hydraulic line. The fifth hydraulic pump is used to transmit oil to the first hydraulic cylinder, the second hydraulic cylinder and / or the third hydraulic cylinder through the pre-charged hydraulic line; The first end of the fourth actuator is connected to the fourth output end of the battery, and the second end of the fourth actuator is connected to the first end of the fifth hydraulic pump. The fourth actuator is used to convert the electrical energy of the battery into mechanical energy to drive the fifth hydraulic pump.

3. The anti-overcharge device for a multi-axis hydraulic system according to claim 1, characterized in that, The second axis control loop further includes a second control valve, and the third axis control loop further includes a third control valve; The first end of the second control valve is connected to the third hydraulic pump, the second end of the second control valve is connected to the second hydraulic cylinder, and the third end of the second control valve is connected to the relief valve. The second control valve is used to receive oil from the third hydraulic pump and transmit the oil to the second hydraulic cylinder or the relief valve; The first end of the third control valve is connected to the fourth hydraulic pump, the second end of the third control valve is connected to the third hydraulic cylinder, and the third end of the third control valve is connected to the relief valve. The third control valve is used to receive the oil from the fourth hydraulic pump and transmit the oil to the third hydraulic cylinder or the relief valve.

4. A method for preventing battery overcharging in a multi-axis hydraulic system, characterized in that, The battery overcharge prevention device applicable to the multi-axis hydraulic system according to any one of claims 1 to 3, the battery overcharge prevention method comprising: Acquire the battery's state of charge and the operating status of the second and third hydraulic cylinders; When the state of charge is greater than or equal to the second threshold, the conduction direction of the second control valve and the third control valve is determined according to the operating state.

5. The method for preventing battery overcharging in a multi-axis hydraulic system according to claim 4, characterized in that, Determining the conduction direction of the second and third control valves based on the operating state includes: When both the second hydraulic cylinder and the third hydraulic cylinder are in an idle state, the second control valve and the third control valve are simultaneously opened to allow the oil to flow to the relief valve.

6. The method for preventing battery overcharging in a multi-axis hydraulic system according to claim 5, characterized in that, When both the second and third hydraulic cylinders are in an idle state, the second and third control valves are simultaneously opened to allow oil to flow to the relief valve, and the system further includes: Obtain the recoverable power of the first actuator; When the power consumption of the third and fourth hydraulic pumps is greater than or equal to the recoverable power, the transmission speed of the oil is controlled by adjusting the rotational speed of the second and third actuators. When the maximum power consumption of the third and fourth hydraulic pumps is less than the recoverable power, the rotational speed of the first actuator is determined based on the maximum power consumption.

7. The method for preventing battery overcharging in a multi-axis hydraulic system according to claim 4, characterized in that, Determining the conduction direction of the second and third control valves based on the operating state includes: When both the second hydraulic cylinder and the third hydraulic cylinder are in operation, the second control valve and the third control valve are simultaneously opened so that the oil flows to the second hydraulic cylinder and the third hydraulic cylinder respectively.

8. The method for preventing battery overcharging in a multi-axis hydraulic system according to claim 7, characterized in that, When both the second hydraulic cylinder and the third hydraulic cylinder are in operation, the second control valve and the third control valve are simultaneously opened to allow oil to flow to the second hydraulic cylinder and the third hydraulic cylinder respectively. The method also includes: Obtain the total power consumption of the first hydraulic pump, the second hydraulic pump, the third hydraulic pump, and the fourth hydraulic pump; The rotational speed of the first actuator is determined based on the total power consumption.

9. The method for preventing battery overcharging in a multi-axis hydraulic system according to claim 4, characterized in that, Determining the conduction direction of the second and third control valves based on the operating state includes: When the second hydraulic cylinder or the third hydraulic cylinder is in operation, the second control valve is controlled to be connected to the second hydraulic cylinder, and the third control valve is controlled to be connected to the relief valve, or the third control valve is controlled to be connected to the third hydraulic cylinder, and the second control valve is controlled to be connected to the relief valve.

10. The method for preventing battery overcharging in a multi-axis hydraulic system according to claim 9, characterized in that, When the second hydraulic cylinder is in operation or the third hydraulic cylinder is in operation, the second control valve is controlled to be connected to the second hydraulic cylinder, and the third control valve is controlled to be connected to the relief valve, or the third control valve is controlled to be connected to the third hydraulic cylinder, and the second control valve is controlled to be connected to the relief valve, including; Obtain the recoverable power of the first actuator; When the maximum power consumption of the first hydraulic pump, the second hydraulic pump, and the third hydraulic pump is greater than or equal to the recoverable power, or when the maximum power consumption of the first hydraulic pump, the second hydraulic pump, and the fourth hydraulic pump is greater than or equal to the recoverable power, the transmission speed of the oil is controlled by adjusting the rotation speed of the second actuator or the third actuator. When the maximum power consumption of the first hydraulic pump, the second hydraulic pump, and the third hydraulic pump is less than the recoverable power, or when the maximum power consumption of the first hydraulic pump, the second hydraulic pump, and the fourth hydraulic pump is less than the recoverable power, the rotational speed of the third actuator or the second actuator is determined based on the difference between the recoverable power and the maximum power consumption, and the rotational speed of the first actuator is determined based on the maximum power consumption.

Images