Control method, braking system and engineering machinery

Abstract

The invention relates to a control method of an electro-hydraulic combined type braking system for engineering machinery, the electro-hydraulic combined type braking system and the engineering machinery. The braking system comprises a braking control device, a hydraulic braking subsystem used for executing hydraulic braking operation and a braking energy recycling subsystem used for recycling braking energy, the braking energy recycling subsystem comprises a motor and a battery, and the control method comprises the steps that braking requirement data and braking force distribution data are obtained; determining a total expected braking force based on the acquired braking requirement data; based on the determined total expected braking force and the obtained braking force distribution data, hydraulic braking force applied by a hydraulic braking subsystem and recovery braking force applied by a braking energy recovery subsystem are determined; and the hydraulic braking subsystem is controlled to apply hydraulic braking force, and the motor is controlled to work in a generator mode to apply recovery braking force. The braking force distribution data includes at least a state of charge of the battery and an operating stroke of the brake actuation device.

Description

Technical Field

[0001] The invention relates to a control method for a braking system of an engineering machine, a braking system and the engineering machine. Background Art

[0002] Construction machinery is widely used in engineering fields such as urban construction, mining, water conservancy and electricity. With the continuous improvement of environmental protection departments' emission requirements for non-road diesel mobile machinery, kinetic energy recovery of construction machinery has always been a hot research field. For example, engineering equipment such as excavators, forklifts, tower cranes, etc. have two rotational movements in a standard cycle, so the slewing mechanism needs to be started and braked frequently. A large amount of kinetic energy in the braking process is converted into heat energy waste through the reversing valve and the overflow valve, resulting in the heat generated by the slewing mechanism accounting for 30% to 40% of the heat generated by the vehicle's hydraulic system. Therefore, the recovery and utilization of the braking energy of construction machinery is of great significance to reducing system heating and saving energy and reducing emissions.

[0003] At present, scholars have proposed various brake energy recovery systems, including pure hydraulic brake energy recovery systems and electrified brake energy recovery systems. The electrified brake energy recovery system can also be called an electro-hydraulic composite brake energy recovery system. The pure hydraulic brake energy recovery system has low energy utilization, complex system and poor reliability. Therefore, the present invention focuses on the electro-hydraulic composite brake energy recovery system.

[0004] In the first type of structure of the electro-hydraulic composite brake energy recovery system, conventional power brake valves are still used, and the motor reverse drag is simply superimposed for braking. The disadvantage of this method is that as long as the brake pedal is operated, hydraulic braking will intervene. Therefore, a part of the vehicle's kinetic energy is always consumed by hydraulic braking, and the remaining recoverable kinetic energy becomes smaller, resulting in low energy recovery efficiency. Moreover, in order to ensure the consistency of the braking operation feeling, the braking force should increase along the brake pedal stroke according to a certain curve. Therefore, in the middle and front section of the brake pedal stroke, the motor cannot apply too much reverse drag, otherwise it will cause excessive braking force in the middle and front section, affecting the braking performance, and thus further reducing the energy recovery efficiency.

[0005] In the second type of structure of the electro-hydraulic composite brake energy recovery system, a front dead zone is set for the conventional power brake valve. Therefore, the power brake valve is not conductive in the front section of the pedal stroke, that is, the hydraulic brake does not intervene. In this way, the braking force in the front section is only provided by the motor back-drag, and the corresponding kinetic energy is fully involved in energy recovery, which increases the recovery efficiency. However, when the battery is fully charged or nearly fully charged, in order to protect the battery, the motor is not allowed to generate back-drag or the size of the back-drag is limited, which will cause no braking force or reduced braking force in the front section of the pedal. Therefore, the consistency of the braking operation feeling deteriorates. Summary of the invention

[0006] The technical problem to be solved by the present invention is to propose a control method for a braking system for engineering machinery, a braking system and engineering machinery, which provide good braking operation consistency while ensuring high energy recovery efficiency.

[0007] According to a first aspect of the present invention, a control method for a braking system of an engineering machine is provided, wherein the braking system comprises a braking operating device, a hydraulic braking subsystem for performing a hydraulic braking operation, and a braking energy recovery subsystem for recovering braking energy, wherein the braking energy recovery subsystem comprises a motor and a battery, and the control method comprises:

[0008] A first step, in which braking requirement data and braking force distribution data are acquired;

[0009] a second step, in which a total expected braking force is determined based on the acquired braking requirement data;

[0010] A third step, in which the hydraulic braking force applied by the hydraulic braking subsystem and the regenerative braking force applied by the brake energy regeneration subsystem are determined based on the determined total desired braking force and the acquired braking force distribution data,

[0011] a fourth step, in which the hydraulic brake subsystem is controlled to apply the hydraulic braking force, and the motor is controlled to operate in a generator mode to apply the regenerative braking force,

[0012] The braking force distribution data includes at least a charge state of the battery and an operating distance of the brake operating device.

[0013] The method according to the present invention achieves the following advantages:

[0014] By simultaneously considering the state of charge of the battery and the operating stroke of the brake operating device, the energy recovery efficiency and the braking operation consistency are taken into account when determining the hydraulic braking force applied by the hydraulic braking subsystem and the regenerative braking force applied by the brake energy recovery subsystem. Moreover, the method can be implemented by a simple structure and low-cost braking system.

[0015] The present invention also relates to a braking system for engineering machinery, a braking system for engineering machinery, the braking system comprising a braking operating device, a hydraulic braking subsystem for performing hydraulic braking operations, and a braking energy recovery subsystem for recovering braking energy.

[0016] The hydraulic brake subsystem includes a hydraulic brake cylinder for generating a braking force and a power brake valve for controlling the hydraulic brake cylinder, wherein the power brake valve includes a front dead zone.

[0017] The braking energy recovery subsystem includes a motor and a battery for performing braking energy recovery.

[0018] The brake system further comprises a brake system control device which is provided to carry out the method according to the invention.

[0019] The invention also relates to a construction machine comprising the brake system. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 is a schematic hydraulic principle diagram of an exemplary embodiment of a brake system according to the present invention.

[0021] Figure 2 is a flow chart of an exemplary embodiment of a control method for a brake system.

[0022] Figure 3 is a flow chart of an exemplary embodiment of a subroutine of a control method.

[0023] Reference numerals list

[0024] 1 Accumulator charging valve

[0025] 2 Accumulator

[0026] 3 Power brake valve

[0027] 4 Brake operating device

[0028] 5 Brake cylinder

[0029] 6. Pressure Sensor

[0030] 7 Solenoid proportional pressure reducing valve

[0031] 8 Parking brake solenoid valve

[0032] 9 Parking brake mechanism

[0033] 10 Motor

[0034] 11 Motor Controller

[0035] 12 Braking system control device

[0036] 41 Spring mechanism DETAILED DESCRIPTION

[0037] The following will describe the control method, braking system and engineering machinery of the braking system for engineering machinery according to the present invention with reference to the accompanying drawings and through specific embodiments. However, the exemplary embodiments can be implemented in various forms and should not be understood as being limited to the embodiments described herein; on the contrary, these embodiments are provided to make the present invention comprehensive and complete and to fully convey the concept of the exemplary embodiments to those skilled in the art.

[0038] Figure 1 FIG. 2 shows a schematic hydraulic principle diagram of an electro-hydraulic composite brake system for engineering machinery according to the present invention. Figure 1 As shown, the braking system includes a brake operating device 4, a hydraulic brake subsystem for performing hydraulic braking operations, and a brake energy recovery subsystem for recovering braking energy. The hydraulic brake subsystem performs hydraulic braking operations based on the operator's operation of the brake operating device 4, and includes: an accumulator charging valve 1, an accumulator 2, a power brake valve 3, a hydraulic brake cylinder 5, and related electronic and hydraulic control devices, sensors, accessories, etc.

[0039] Here, the accumulator charging valve 1 is used to charge the accumulator 2 with hydraulic fluid. The accumulator 2 is connected to the power brake valve 3. When the power brake valve 3 is turned on, the brake fluid in the accumulator 2 is guided to the brake cylinder 5, thereby providing hydraulic braking force. The power brake valve 3 is constructed to have a front dead zone, especially a significantly larger front dead zone.

[0040] In the present embodiment, the brake operating device 4 is a brake pedal. In addition, a travel sensor (not shown) is provided to detect the operating travel of the brake operating device 4. Here, the brake operating device 4 can be mechanically connected to the power brake valve 3 on the one hand, so that it can directly cause control of the power brake valve 3 at least over a part of the operating travel (the front dead zone of the power brake valve 3). On the other hand, the brake operating device 4 is mechanically connected to a brake feel feedback device 41 to provide the operator with feedback on the brake feel. The brake feel feedback device can also be referred to as a brake feel simulator, which is implemented as a spring mechanism 41 in the present embodiment. Moreover, the brake operating device 4 is electronically connected to the power brake valve control actuator. It is in Figure 1 , the electromagnetic proportional pressure reducing valve 7 is shown. In the present embodiment, the electronic connection is indirectly realized by the following method: the control signal of the brake operating device 4 is transmitted to the brake system control device 12, and the brake system control device 12 uses the control signal to control the power brake valve control actuator. Of course, the connection between the brake operating device 4 and the power brake valve control actuator can also be realized directly by the following method: for example, the control signal of the brake operating device 4 is directly transmitted to the electromagnetic proportional pressure reducing valve 7 (or its controller) to realize direct control.

[0041] When the brake operating device 4 is initially operated, it moves the valve core of the power brake valve 3 through the mechanical connection with the power brake valve 3. However, when the operating stroke does not exceed the dead zone of the front section of the power brake valve 3, the movement of the valve core of the power brake valve 3 does not cause the conduction of the power brake valve 3, so the hydraulic brake does not intervene. During this period, the brake feeling feedback device, that is, the spring mechanism 41 is compressed and uses its spring force to provide brake feeling feedback.

[0042] As the brake operating device 4 is further operated, the operating stroke reaches and exceeds the front dead zone of the power brake valve 3. After the operating stroke reaches the front dead zone of the power brake valve 3, the power brake valve 3 is turned on, and the reaction force of the valve core of the power brake valve 3 on the brake operating device 4 will increase rapidly. Therefore, after the operating stroke reaches the front dead zone of the power brake valve 3, the operating stroke of the brake operating device 4 does not directly act on the power brake valve 3. Instead, the brake system control device 12 receives the operating signal of the brake operating device 4 and controls the electromagnetic proportional pressure reducing valve 7 based on the operating signal. The electromagnetic proportional pressure reducing valve 7 controls the conduction of the power brake valve 3 based on the operating signal. Here, the power brake valve 3 is "adjusted without directly relying on the brake operating device 4". The control of the electromagnetic proportional pressure reducing valve 7 by the brake system control device 12 can not only consider the stroke of the brake operating device 4, but also other parameters (such as but not limited to the state of the motor 10, the battery state, etc.).

[0043] During this period, the spring mechanism 41 is also compressed and uses its spring force to provide brake feeling feedback. The spring mechanism 41 is implemented as a nonlinear spring mechanism, which also provides a nonlinear spring force-travel curve, thereby providing consistent brake feeling feedback over the entire operating stroke. Such a nonlinear spring may be realized, for example, by connecting a certain number of elastic elements in series or parallel, or by using a specific material.

[0044] Of course, the brake operating device 4 may also be other operating devices besides the brake pedal, such as but not limited to a manual brake lever, etc. The power brake valve 3 may also be connected to the brake operating device 4 in other connection modes, such as through an electronic connection (such as a wire control brake structure used in an automobile), etc. Alternatively, the power brake valve 3 may also be indirectly connected to the brake operating device 4, such as through an electronic control unit. In the case where the power brake valve 3 is electronically connected to the brake operating device 4, for example, the opening of the power brake valve 3 and the hydraulic braking force provided are controlled according to the relationship between the stored operating stroke and the hydraulic braking force.

[0045] exist Figure 1In the embodiment shown, two brake cylinders 5 are provided. Of course, more or less brake cylinders 5 may be provided depending on the application requirements. Pressure sensors 6 are provided in the pipelines of the brake cylinders 5 to detect the brake pressure actually provided by each brake cylinder 5, and then to obtain the braking force actually provided by the brake cylinders 5. Of course, it is also conceivable to provide sensors at other positions to detect the braking force actually provided.

[0046] Power brake valve control actuator

[0047] Here, the opening of the power brake valve 3 is controlled by a control actuator preferably designed as an electromagnetic proportional pressure reducing valve 7. Of course, other known control actuators may also be provided, such as other electromagnetic proportional valves or other types of travel actuators, etc. It is even conceivable to integrate a new valve module, etc. in the power brake valve 3, as long as the opening of the power brake valve 3 can be adjusted under the control of the brake system control device 12.

[0048] In the embodiment shown, the power brake valve 3 has a mechanical and hydraulic dual control configuration. That is, the power brake valve 3 can be mechanically controlled by the brake operating device 4 directly connected thereto (the front section), and can also be hydraulically adjusted by the electromagnetic proportional pressure reducing valve 7 connected thereto (beyond the front section).

[0049] The hydraulic system further comprises a parking brake solenoid valve 8 and a parking brake mechanism 9 for providing a parking brake function.

[0050] Here, only an exemplary embodiment of the hydraulic brake subsystem is shown. Those skilled in the art can imagine that all hydraulic brake subsystems existing in the prior art are applicable to the present invention, and no further description is given here. As for the specific arrangement and connection relationship of each component in the hydraulic system, those skilled in the art can know a variety of different design schemes based on the prior art, and no one is listed here.

[0051] The braking energy recovery subsystem includes a motor 10 for performing braking energy recovery, a battery (not shown), a motor controller 11, and related electronic control devices, sensors, accessories, etc. During the braking energy recovery process, the motor 10 works in a generator mode and reverses the moving parts or is driven by the moving parts, and the electrical energy generated is fed into the battery.

[0052] The brake system control device 12 is connected to the motor controller 11 and the electromagnetic proportional pressure reducing valve 7, and outputs control instructions to the two. At the same time, the brake system control device 12 also receives other information, such as vehicle speed signal, battery power signal, pressure signal of the pressure sensor 6, operation stroke signal of the brake operating device 4, etc.

[0053] Figure 2The flowchart of the control method for the braking system of the construction machinery according to the present invention is shown. The method can be activated by a braking request, that is, the method starts when there is a braking request. The braking request can be represented by a signal of the brake operating device 4, or by a signal of other automatic auxiliary equipment, such as an emergency brake device, an automatic driving device, etc. Figure 2 As shown, in the method, firstly in the first step S01 , braking requirement data and braking force distribution data are acquired.

[0054] The braking requirement data includes at least one of the following data: vehicle speed data, braking operation data, and braking requirement data of automatic assistance equipment. Here, the vehicle speed data can be directly obtained from the sensor device, such as from the vehicle speed sensor; it can also be calculated using the signal from the sensor device, such as using the acceleration sensor signal or the wheel speed sensor signal. Of course, the vehicle speed data can also be obtained from a GPS device, that is, the instantaneous vehicle speed is calculated from the change in the vehicle position. The braking operation data characterizes the operator's operating stroke of the braking operation device 4, such as the brake pedal or the brake lever. The braking operation data comes from, for example, the operation sensor of the brake operation device 4 of the construction machinery, such as the travel sensor of the brake pedal. If the construction machinery includes automatic assistance equipment that may make braking requirements, such as emergency braking equipment, automatic driving equipment, etc., the braking requirement data of these automatic assistance equipment are also considered here.

[0055] The braking force distribution data at least includes: the state of charge of the battery and the operating stroke of the brake operating device 4. Alternatively, the braking force distribution data may also include the stored braking force distribution ratio between the hydraulic braking force and the recovery braking force. For example, there may be a braking force distribution ratio stored in the form of a lookup table. In this case, by inputting information such as the state of charge of the battery, the operating stroke of the brake operating device 4, and the vehicle speed, the distribution ratio of the hydraulic braking force to the recovery braking force can be found.

[0056] In a second step S02, a total expected braking force is determined based on the acquired braking requirement data;

[0057] In the third step S03, based on the determined total desired braking force and the acquired braking force distribution data, the hydraulic braking force applied by the hydraulic braking subsystem and the recovery braking force applied by the brake energy recovery subsystem (ie, the anti-drag torque applied by the motor 10) are determined.

[0058] In the fourth step S04 , the hydraulic brake subsystem is controlled to apply the hydraulic braking force, and the motor 10 is controlled to work in a generator mode to apply the regenerative braking force.

[0059] Next, reference is made to an exemplary embodiment of a subroutine of the third step S03. Figure 3 The third step S03 is described in detail. As shown in the figure, the third step S03 includes the following sub-steps:

[0060] Step S301 : Compare the operation stroke of the brake operating device 4 with the first operation threshold, and determine whether the operation stroke of the brake operating device 4 is less than or equal to the first operation threshold. The first operation threshold represents the operation stroke corresponding to the front dead zone of the power brake valve 3 .

[0061] If it is determined in step S301 that the operation stroke of the brake operating device 4 is less than or equal to the first operation threshold, then go to step S302. In this case, the operation of the brake operating device 4, especially the brake pedal, does not exceed the front dead zone of the power brake valve 3, so the power brake valve 3 is not conductive. Therefore, in step S302, it is expected that all braking forces are provided by the brake energy recovery subsystem, that is, the expected recovery braking force applied by the brake energy recovery subsystem is determined to be equal to the total expected braking force, and the expected hydraulic braking force applied by the hydraulic brake subsystem is determined to be equal to zero. And go to step S304. That is, in this expected situation (that is, the battery charge state allows), all braking forces are provided by the motor 10, and the hydraulic brake subsystem does not work. Specifically, the brake system control device 12 makes the electromagnetic proportional pressure reducing valve 7 inoperative and sends instructions to the motor controller 11, so that the motor 10 applies anti-drag force. At the same time, the power brake valve 3 remains closed and the hydraulic brake does not intervene.

[0062] If it is determined in step S302 that the operation stroke signal is greater than the first operation threshold, then go to step S303. In this case, the operation of the brake operating device 4, especially the brake pedal, has exceeded the front dead zone of the power brake valve 3, so the power brake valve 3 is turned on.

[0063] In step S305, the estimated hydraulic braking force is obtained based on the operation stroke, and the estimated recovery braking force is determined based on the estimated hydraulic braking force and the total expected braking force. Here, the hydraulic braking force can be determined based on a preset ratio, for example but not limited to, it can be set that all braking forces are provided by the hydraulic system. Alternatively, it is also possible to determine the ratio of the hydraulic braking force to the recovery braking force, for example, by looking up a table or other forms of stored data. Of course, there may be other braking force determination methods based on other specific structures, which will not be repeated here. Then, the estimated recovery braking force is determined by the difference between the estimated hydraulic braking force and the total expected braking force.

[0064] In step S304, the maximum anti-drag force that the braking energy recovery subsystem can provide is calculated based on the current battery charge state. Then, in step S305, the maximum anti-drag force is compared with the expected recovery braking force, and it is determined whether the maximum anti-drag force is greater than or equal to the expected recovery braking force.

[0065] If it is determined in step S305 that the maximum anti-drag force is greater than or equal to the estimated regenerative braking force, the process proceeds to step S306. In step S306, the regenerative braking force is determined to be equal to the estimated regenerative braking force, and the hydraulic braking force is determined to be equal to the estimated hydraulic braking force. Then, the subroutine ends and returns to the main process.

[0066] If it is determined in step S305 that the maximum anti-drag force is less than the total expected braking force, then go to step S307. In step S307, the regenerative braking force applied by the motor 10 is determined to be equal to the maximum anti-drag force, and the hydraulic braking force applied by the hydraulic braking subsystem is determined to be equal to the sum of the expected hydraulic braking force and a supplementary braking force, which is the difference between the expected regenerative braking force and the maximum anti-drag force. In this case, the motor 10 performs braking with the maximum anti-drag force allowed by the battery charge state, and the insufficient braking force is supplemented by the hydraulic braking subsystem. Figure 1 In the illustrated configuration, the brake system control device 12 outputs a command to the electromagnetic proportional pressure reducing valve 7 to control the power brake valve 3, thereby providing a supplementary braking force. Then, the subroutine ends and returns to the main flow.

[0067] In addition, the method may also include feedback control, wherein the hydraulic braking force and the recovery braking force actually provided are detected and the sum of the two is compared with the total desired braking force, and the hydraulic braking force and the recovery braking force are adjusted based on the comparison result. Figure 1 As shown, the actual brake pressure may be determined based on the signal of the pressure sensor 6. At this time, the ECM can calculate whether the actual brake pressure meets the braking demand based on the total expected braking force. If the braking force is too large, the motor 10 is controlled to reduce the braking force of the motor 10; if the braking force is too small, the electromagnetic proportional pressure reducing valve 7 is controlled to appropriately increase the opening of the power brake valve 3 to increase the hydraulic braking force. Through the controllable motor 10 anti-drag torque and the compensation of the electromagnetic proportional pressure reducing valve 7, the operator's operating stroke and the actual output total braking force meet a reasonable curve.

[0068] Industrial Applicability

[0069] The following describes how the brake system works.

[0070] When the brake operating device 4, such as a brake pedal or a hand brake lever, is operated, on the one hand, the operating stroke of the brake operating device 4 is transmitted to the brake system control device 12 connected to the brake operating device 4. On the other hand, the power brake valve 3, which is also connected to the brake operating device 4, also receives the stroke of the brake operating device 4. If the operating stroke indicates that the front dead zone of the power brake valve 3 has not been crossed, the power brake valve 3 is not conductive. In this case, the motor 10 is preferentially used to provide the braking force. The maximum reverse drag force that can be provided by the brake energy recovery subsystem is calculated based on the current battery charge state. If the maximum reverse drag force is greater than or equal to the total expected braking force, the motor 10 provides all the braking force and the hydraulic brake subsystem does not provide the braking force. On the contrary, if the maximum reverse drag force is less than the total expected braking force, the brake system control device 12 sends a command to the electromagnetic proportional pressure reducing valve 7, and the electromagnetic proportional pressure reducing valve 7 controls the power brake valve 3 to provide a supplementary braking force, that is, the difference between the total expected braking force and the maximum reverse drag force.

[0071] In the case where the braking operation exceeds the front dead zone of the power brake valve 3, the power brake valve 3 is turned on. In this case, the predicted hydraulic braking force and the predicted recovery braking force are calculated by the brake system control device 12. If the maximum anti-drag force calculated by the current battery charge state is greater than or equal to the predicted recovery braking force, the torque is provided based on the above calculation. That is, the recovery braking force is determined to be equal to the predicted recovery braking force and the hydraulic braking force is determined to be equal to the predicted hydraulic braking force. On the contrary, if the maximum anti-drag force is less than the total expected braking force, the motor 10 only provides the maximum anti-drag force and the brake system control device 12 sends a command to the electromagnetic proportional pressure reducing valve 7, which further controls the power brake valve 3 to provide a supplementary braking force so that the total braking force reaches the total expected braking force.

[0072] The control method and braking system according to the present invention have the following advantages:

[0073] 1. When the battery power does not need to limit the anti-drag force of the motor 10, the hydraulic brake is only intervened after the front dead zone of the power brake valve 3, and the front braking is all achieved by the motor 10, thereby improving the energy recovery rate.

[0074] 2. When the battery power requires limiting the reverse drag force of the motor 10, such as when the battery is fully charged or nearly fully charged, in the front braking, although the braking operation of the brake operating device 4 alone cannot open the power brake valve 3, the power brake valve 3 is opened at a suitable position through the output of the electromagnetic proportional pressure reducing valve 7, and the hydraulic system intervenes. Therefore, the problem of no braking force or small braking force in the front stage in this state is solved, making the braking performance more consistent and the operating experience better.

[0075] 3. Through the controllable reverse torque of the motor 10 and the compensation of the electromagnetic proportional pressure reducing valve 7, the operator's operating force and the total expected braking force actually outputted during the entire braking process both conform to a reasonable curve.

[0076] 4. Compared with conventional machines, only one electromagnetic proportional pressure reducing valve 7 is added, and the power brake valve 3 only needs to be slightly modified. The rest of the parts can be borrowed, and the versatility is strong. When the newly added electromagnetic proportional pressure reducing valve 7 fails, the power brake valve 3 can still work normally by mechanical control alone, and can still exert the maximum hydraulic braking force. The safety of the entire system is not less than that of the conventional hydraulic brake subsystem.

[0077] It is obvious that various modifications and variations may be made to the embodiments disclosed above without departing from the scope or spirit of the invention for those skilled in the art. Other embodiments of the invention will be apparent to those skilled in the art from the practice of the invention disclosed in this specification. This specification and the examples disclosed therein should be considered to be illustrative only.

Claims

1. A control method for a brake system of an engineering machine, wherein the brake system comprises a brake operating device, a hydraulic brake subsystem for performing a hydraulic brake operation, and a brake energy recovery subsystem for recovering brake energy, wherein the brake energy recovery subsystem comprises a motor and a battery, and the control method comprises: A first step (S01), in which braking requirement data and braking force distribution data are acquired; a second step (S02), in which a total expected braking force is determined based on the acquired braking requirement data; a third step (S03), in which the hydraulic braking force applied by the hydraulic braking subsystem and the regenerative braking force applied by the regenerative braking subsystem are determined based on the determined total desired braking force and the acquired braking force distribution data, A fourth step (S04), in which the hydraulic brake subsystem is controlled to apply the hydraulic braking force, and the motor is controlled to operate in a generator mode to apply the regenerative braking force, It is characterized in that The braking force distribution data includes at least a charge state of the battery and an operating distance of the brake operating device.

2. The control method according to claim 1, characterized in that: The braking request data includes at least one of the following data: vehicle speed data, brake manipulation data, and braking request data of an automatic assist device.

3. The control method according to claim 1, characterized in that: The third step comprises: - determining an estimated regenerative braking force and an estimated hydraulic braking force based on the total desired braking force and the operating travel of the brake operating device; - determining a hydraulic braking force applied by a hydraulic braking subsystem and a regenerative braking force applied by a brake energy recovery subsystem based on the predicted regenerative braking force, the predicted hydraulic braking force, the state of charge of the battery and the total desired braking force.

4. The control method according to claim 3, characterized in that: Determining the estimated regenerative braking force and the estimated hydraulic braking force includes: - determining whether the operation stroke of the brake operating device is less than or equal to a first operating threshold; - in the case where it is determined that the operation stroke is less than or equal to a first manipulation threshold, determining the estimated regenerative braking force to be equal to the total desired braking force, and determining the estimated hydraulic braking force to be equal to zero; - in a case where it is determined that the operation stroke is greater than a first manipulation threshold, an estimated hydraulic braking force is obtained based on the operation stroke, and the estimated regenerative braking force is determined based on the estimated hydraulic braking force and the total desired braking force.

5. The control method according to claim 4, characterized in that: - deriving the estimated hydraulic braking force based on the operation stroke includes: deriving the estimated hydraulic braking force according to a stored relationship between the operation stroke and the estimated hydraulic braking force; - determining the predicted regenerative braking force based on the predicted hydraulic braking force and the total desired braking force comprises: determining the predicted regenerative braking force equal to the difference between the total desired braking force and the predicted hydraulic braking force.

6. The control method according to claim 4, characterized in that: - The hydraulic brake subsystem includes a hydraulic brake cylinder for generating braking force and a power brake valve for controlling the hydraulic brake cylinder, The first manipulation threshold represents an operation stroke corresponding to a front dead zone of the power brake valve.

7. The control method according to claim 4, characterized in that: The third step also includes: -Calculate the maximum anti-drag force that the regenerative braking system can provide based on the current battery state of charge; - determining whether the maximum anti-drag force is greater than or equal to the expected recovery braking force; - in the case where it is determined that the maximum anti-drag force is greater than or equal to the expected regenerative braking force, determining the regenerative braking force to be equal to the expected regenerative braking force and determining the hydraulic braking force to be equal to the expected hydraulic braking force; - in the case where it is determined that the maximum anti-drag force is less than the estimated regenerative braking force, the regenerative braking force is determined to be equal to the maximum anti-drag force, and the hydraulic braking force is determined to be the sum of the estimated hydraulic braking force and a supplementary braking force, the supplementary braking force being the difference between the estimated regenerative braking force and the maximum anti-drag force.

8. The control method according to claim 1, characterized in that: The control method further comprises feedback control, wherein the hydraulic braking force and the recovery braking force actually provided are detected and the sum of the two is compared with the total desired braking force, and the hydraulic braking force and the recovery braking force are adjusted based on the comparison result.

9. A braking system for engineering machinery, the braking system comprising a braking operating device (4), a hydraulic braking subsystem for performing hydraulic braking operations, and a braking energy recovery subsystem for recovering braking energy, The hydraulic brake subsystem comprises a hydraulic brake cylinder (5) for generating a braking force and a power brake valve (3) for controlling the hydraulic brake cylinder (5), wherein the power brake valve (3) comprises a front dead zone, The braking energy recovery subsystem comprises a motor (10) and a battery for performing braking energy recovery. It is characterized in that The brake system further comprises a brake system control device (12), which is configured to execute the method according to any one of claims 1 to 8.

10. The braking system according to claim 9, characterized in that: The hydraulic brake subsystem further comprises a power brake valve control actuator, wherein the power brake valve (3) is constructed such that: when the operating stroke of the brake operating device (4) does not exceed the front dead zone, the brake operating device (4) directly acts on the power brake valve (3); when the operating stroke of the brake operating device (4) reaches and exceeds the front dead zone, the brake operating device (4) does not directly act on the power brake valve (3), and the power brake valve control actuator controls the opening of the power brake valve (3) based on the operating stroke of the brake operating device (4).

11. A construction machine comprising the brake system according to claim 9 or 10.

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