A control method for a braking system and a braking system

Abstract

The present invention relates to the technical field of braking systems, and specifically discloses a braking system control method and a braking system. The braking system control method provides the maximum recovery torque through the energy recovery system when it is determined that the total required braking torque of the vehicle is greater than the maximum recovery torque that the energy recovery system can provide, and the braking system provides a braking torque, where the braking torque = the total required braking torque - the maximum recovery torque. The method then obtains the slip rate of each wheel in real time. When the slip rate of at least one wheel is greater than a first set value, the vehicle is immediately stopped or its speed is reduced to below a certain level, which is safest for the driver. By reducing the maximum recovery torque provided by the energy recovery system to zero and increasing the braking torque provided by the braking system, and then adjusting the braking torque provided to each wheel by the braking system based on the slip rate of each wheel, interference with the braking effect by the energy recovery system can be avoided, thereby ensuring driving safety.

Description

Technical Field

[0001] The present invention relates to the technical field of brake systems, and in particular to a control method of a brake system and a brake system. Background Art

[0002] Braking energy regeneration is a key energy-saving technology in modern vehicles. Especially for new energy vehicles and autonomous vehicles, braking energy regeneration can effectively avoid energy waste and increase driving range.

[0003] In the prior art, brake energy recovery technology determines the vehicle's braking mode based on brake pedal signals, thereby determining whether energy recovery is required. For example, in a previous patent application with application number CN201810292527.4, a brake energy recovery method is provided, which includes simultaneously obtaining the total required braking torque required by the vehicle and the energy recovery torque that can be generated by the energy recovery system; comparing the total required braking torque and the energy recovery torque; and allocating the total required braking torque based on the comparison result. If the total required braking torque is less than the energy recovery torque, the energy recovery system is used to brake the vehicle to recover energy; if the total required braking torque is greater than the energy recovery torque, the excess braking torque is generated by the braking system. However, this brake energy recovery method does not take braking safety into consideration. When the energy recovery system participates in energy recovery, the energy recovery system applies torque to the drive shaft, while the braking system usually applies torque to the non-drive shaft. This will cause an imbalance in the braking torque on the drive shaft and the non-recovery shaft, which will to some extent interfere with the braking effect of the braking system. Specifically, since the torque provided by the energy recovery system may be as high as 0.3g, when it is very different from the braking torque of the non-recovery axle, the wheels on the recovery axle are prone to a large slip rate. At this time, it is safest for the driver to stop the vehicle immediately or reduce the speed to below a certain level. However, the braking torque provided by the braking system is not the total required torque, which will affect the braking effect. Therefore, it will cause the time for the vehicle to go from moving to stationary to be prolonged, which can easily lead to safety accidents. Summary of the Invention

[0004] The purpose of the present invention is to provide a control method and a braking system for a braking system, so as to solve the problem in the existing control method of the braking system that when the energy recovery system participates in energy recovery, it will interfere with the braking effect of the braking system to a certain extent, which may easily lead to safety accidents.

[0005] In one aspect, the present invention provides a method for controlling a braking system, the method comprising:

[0006] Get the vehicle's braking request;

[0007] Obtaining the total required braking torque of the vehicle;

[0008] Determining that the total required braking torque of the vehicle is greater than the maximum regenerative torque that the energy regeneration system can provide;

[0009] The energy recovery system provides the maximum recovery torque, and the braking system provides the braking torque. Braking torque = total required braking torque - maximum recovery torque;

[0010] Get the slip rate of each wheel in real time;

[0011] determining that a slip ratio of at least one of the wheels is greater than a first set value;

[0012] The maximum regenerative torque provided by the energy recovery system is reduced to zero, and the braking torque provided by the braking system is increased;

[0013] The braking torque provided by the braking system to each of the wheels is adjusted based on the slip ratio of each wheel.

[0014] As a preferred technical solution for the control method of the braking system, if the total required braking torque of the vehicle is not greater than the maximum recovery torque;

[0015] Only the energy recovery system provides regenerative torque.

[0016] As a preferred technical solution for the control method of the braking system, obtaining the total required braking torque of the vehicle includes:

[0017] Get the rotation angle of the brake pedal;

[0018] A total required braking torque is determined based on the rotational angle.

[0019] As a preferred technical solution of the control method of the braking system, adjusting the braking torque provided by the braking system to each wheel based on the slip rate of each wheel includes:

[0020] If the slip rate of the wheel is greater than a second set value; the second set value is greater than the first set value;

[0021] The braking torque provided by the braking system to the wheel is reduced.

[0022] As a preferred technical solution of the control method of the braking system, if the slip rate of the wheel is less than the second set value;

[0023] The braking torque provided by the braking system to the wheels is increased.

[0024] As a preferred technical solution of the control method of the braking system, increasing the braking torque provided by the braking system to the wheel includes:

[0025] The braking torque of the wheel is gradually increased with a first set torque as a step size until the slip rate of the wheel is not less than the second set value.

[0026] As a preferred technical solution of the control method of the braking system, reducing the braking torque provided by the braking system to the wheel includes:

[0027] The braking torque of the wheel is gradually reduced in steps of the second set torque until the slip rate of the wheel is less than the second set value.

[0028] As a preferred technical solution for the control method of the braking system, the braking system includes a hydraulic braking module, a plurality of first brakes, a plurality of mechanical power units, and a plurality of second brakes; the hydraulic braking module is capable of hydraulically driving the plurality of first brakes, and the plurality of mechanical power units are capable of mechanically driving the plurality of second brakes in a one-to-one correspondence; a portion of the wheels are installed with the first brakes, and another portion of the wheels are installed with the second brakes;

[0029] The braking torque provided by the lifting brake system includes:

[0030] If the total required braking torque does not exceed the set braking torque upper limit threshold;

[0031] Calculate the shared torque of each brake, shared torque = total required braking torque / (total number of first brakes + total number of second brakes);

[0032] If the total required braking torque exceeds the braking torque upper limit threshold;

[0033] Calculate the shared torque of each brake, shared torque = braking torque upper limit threshold / (total number of first brakes + total number of second brakes);

[0034] The hydraulic brake module drives each of the first brakes to output the shared torque;

[0035] A plurality of mechanical power units drive the second brakes in a one-to-one correspondence to output the shared torque.

[0036] As a preferred technical solution of the control method of the braking system, the hydraulic brake module includes a fluid reservoir, a brake master cylinder and a main pressure building unit, both of which are used to output fluid to each of the first brakes, a first control valve for controlling the connection or disconnection between the brake master cylinder and the first brake, and a second control valve for controlling the connection or disconnection between the brake master cylinder and the first brake, the main pressure building unit having a first oil replenishment circuit and a second oil replenishment circuit, the first oil replenishment circuit connecting the fluid reservoir and the input interface of the cylinder body of the main pressure building unit, the second oil replenishment circuit connecting the fluid reservoir and the oil replenishment interface of the cylinder body of the main pressure building unit, the second oil replenishment circuit being provided with a one-way valve that only allows fluid to flow from the fluid reservoir to the cylinder body of the main pressure building unit, and the oil replenishment interface being located between the input interface and the output interface of the main pressure building unit;

[0037] When adjusting the braking torque provided by the braking system to each of the wheels based on the slip ratio of each wheel;

[0038] Real-time acquisition of the amount of oil in the first cylinder of the main pressure-building unit;

[0039] When it is determined that the oil volume is less than the set oil volume, the second control valve is closed for a set time and then opened, and within the set time of closing the second control valve, the piston of the main pressure building unit is controlled to move between the oil replenishment interface and the input interface.

[0040] On the other hand, the present invention provides a braking system for implementing the braking system control method in any of the above solutions.

[0041] The beneficial effects of the present invention are:

[0042] The present invention provides a control method for a braking system and a braking system. When it is determined that the total required braking torque of the vehicle is greater than the maximum recovery torque that can be provided by the energy recovery system, the control method of the braking system provides the maximum recovery torque through the energy recovery system, and the braking system provides the braking torque, braking torque = total required braking torque - maximum recovery torque, and then obtains the slip rate of each wheel in real time. When the slip rate of at least one wheel is greater than a first set value, the vehicle stops immediately or reduces the speed to below a certain level, which is the safest for the driver. By reducing the maximum recovery torque provided by the energy recovery system to zero and increasing the braking torque provided by the braking system, and then adjusting the braking torque provided to each wheel by the braking system based on the slip rate of each wheel, it is possible to avoid interference with the braking effect by the energy recovery system and ensure driving safety. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] Figure 1 The structure of the braking system in the embodiment of the present invention is shown in FIG. Figure 1 ;

[0044] Figure 2 The structure of the braking system in the embodiment of the present invention is shown in FIG. Figure 2 ;

[0045] Figure 3 The structure of the braking system in the embodiment of the present invention is shown in FIG. Figure 3 ;

[0046] Figure 4 The structure of the braking system in the embodiment of the present invention is shown in FIG. Figure 4 ;

[0047] Figure 5 The structure of the braking system in the embodiment of the present invention is shown in FIG. Figure 5 ;

[0048] Figure 6 The structure of the braking system in the embodiment of the present invention is shown in FIG. Figure 6 ;

[0049] Figure 7 Flowchart of a method for controlling a braking system in an embodiment of the present invention.

[0050] In the picture:

[0051] 100, first brake; 200, second brake; 300, wheel;

[0052] 1. Hydraulic brake module; 2. Mechanical power unit; 3. First controller; 4. Second controller; 5. First power supply; 6. Second power supply;

[0053] 11. Liquid storage tank;

[0054] 12. Brake master cylinder; 121. Independent hydraulic chamber; 122. Common hydraulic chamber;

[0055] 13. Brake pedal;

[0056] 14. Main pressure-building unit; 141. First motor; 142. First screw; 143. Leather cup; 144. First piston; 145. First cylinder; 146. Rotation angle sensor;

[0057] 15. Displacement sensor;

[0058] 161, first oil circuit; 162, second oil circuit; 163, third oil circuit; 164, fourth oil circuit; 165, first oil supply circuit; 166, second oil supply circuit; 167, fifth oil circuit; 168, sixth oil circuit;

[0059] 171, first control valve; 172, second control valve; 173, third control valve; 174, fourth control valve; 175, fifth control valve;

[0060] 18. One-way valve;

[0061] 19. Simulator;

[0062] 20. Pressure sensor;

[0063] 21. Second motor; 22. Second screw rod; 23. Pushing member; 24. Motor housing. DETAILED DESCRIPTION

[0064] The technical solution of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the embodiments described are only some embodiments of the present invention, not all embodiments. All other embodiments obtained by ordinary technicians in this field based on the embodiments of the present invention without making any creative efforts shall fall within the scope of protection of the present invention.

[0065] In the description of the present invention, it should be noted that the terms "center", "up", "down", "left", "right", "vertical", "horizontal", "inside", "outside" and the like indicate positions or positional relationships based on the positions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and are not intended to indicate or imply that the devices or elements referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as limiting the present invention. In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance. Among them, the terms "first position" and "second position" are two different positions, and the first feature being "above", "above" and "above" the second feature includes the first feature being directly above and obliquely above the second feature, or simply means that the first feature is higher in level than the second feature. The first feature being "below", "below" and "below" the second feature includes the first feature being directly below and obliquely below the second feature, or simply means that the first feature is lower in level than the second feature.

[0066] In the description of the present invention, it should be noted that, unless otherwise expressly specified or limited, the terms "mounted," "connected," and "connected" should be understood in a broad sense. For example, they may refer to fixed, detachable, or integral connections; mechanical or electrical connections; direct or indirect connections through an intermediate medium; and internal communication between two components. Those skilled in the art will understand the specific meanings of the above terms in the present invention based on the specific circumstances.

[0067] The following describes embodiments of the present invention in detail. Examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are intended only to explain the present invention and are not to be construed as limiting the present invention.

[0068] Current braking energy recovery technology simultaneously obtains the total braking torque required by the vehicle and the energy recovery torque that can be generated by the energy recovery system; then compares the total braking torque required with the energy recovery torque; and based on the comparison result, allocates the total braking torque required. If the total braking torque required is less than the energy recovery torque, the energy recovery system is used to brake the vehicle, allowing it to recover energy; if the total braking torque required is greater than the energy recovery torque, the excess braking torque is generated by the braking system. However, this braking energy recovery method does not consider braking safety. When the energy recovery system participates in energy recovery, it can interfere with the braking effect of the braking system to a certain extent. Specifically, because the energy recovery efficiency of the energy recovery system is lower than that of direct braking by the braking system, especially when the vehicle's wheels have a large slip rate, it is safest for the driver to stop the vehicle immediately or reduce the speed to below a certain level. However, the braking torque provided by the braking system is not the total required torque, which affects the braking effect. This can prolong the time it takes for the vehicle to stop, which can easily lead to safety accidents.

[0069] To address this issue, this embodiment provides a braking system and a method for controlling the braking system to solve the above-mentioned problem.

[0070] Specifically, if Figures 1 to 5 As shown, the braking system includes a first brake 100, a second brake 200, a hydraulic brake module 1, and a mechanical power unit 2. The first brake 100 and the second brake 200 are both used to brake wheels 300, with the hydraulic brake module 1 being used to drive the first brake 100, and the mechanical power unit 2 being used to drive the second brake 200. In this embodiment, the number of first brakes 100 and second brakes 200 is not limited. This embodiment exemplifies a solution with two first brakes 100 and two second brakes 200. Preferably, the two first brakes 100 are used to brake the two wheels 300 on the front axle of the vehicle, and the two second brakes 200 are used to brake the two wheels 300 on the rear axle of the vehicle.

[0071] Because the second brake 200 is driven by the mechanical power unit 2, compared to existing technologies, an oil circuit for the second brake 200 is eliminated, thereby reducing the number of control valves used in the oil circuit. This simplifies the overall structure, reduces maintenance, and significantly reduces costs. Furthermore, because the first brake 100 is hydraulically controlled and the second brake 200 is mechanically controlled, the hydraulic and mechanical controls provide redundant protection. Therefore, if the hydraulic control fails, the mechanical control can still achieve braking.

[0072] The hydraulic brake module 1 includes a fluid reservoir 11 and a master cylinder 12. The reservoir 11 stores fluid and is connected to the input of the master cylinder 12. A brake pedal 13 is drivingly connected to the piston of the master cylinder 12. The output of the master cylinder 12 supplies fluid to the first brake 100. Specifically, when the brake pedal 13 is pressed, it pushes the brake piston in the master cylinder 12 to move. This pushes the fluid in the master cylinder 12 out of its output toward the first brake 100, enabling braking control of the first brake 100 through the master cylinder 12.

[0073] The master brake cylinder 12 may be a double-chamber oil cylinder or a single-chamber oil cylinder. Figure 1 and Figure 2 As shown, the master cylinder 12 has two independent hydraulic chambers 121, one of which is used to supply oil to a portion of the first brakes 100; the other is used to supply oil to another portion of the first brakes 100. Specifically, in this embodiment, when the master cylinder 12 has two independent hydraulic chambers 121, the two independent hydraulic chambers 121 supply oil to the two first brakes 100 respectively. Figures 3 and 4 As shown, the master brake cylinder 12 has a common hydraulic chamber 122 , which is used to supply oil to all first brakes 100 .

[0074] In this embodiment, the hydraulic brake module 1 also includes a main pressure-building unit 14 and a first controller 3. In this embodiment, the first controller 3 is specifically an on-board computer (ECU, Electronic Control Unit). The input end of the main pressure-building unit 14 is connected to the fluid storage tank 11, and the output end of the main pressure-building unit 14 is used to supply oil to the first brake 100. The first controller 3 is communicatively connected to the main pressure-building unit 14. When the driver steps on the brake pedal 13, the displacement sensor 15 can detect the movement of the brake piston of the brake master cylinder 12. The displacement sensor 15 sends the detected movement to the first controller 3. The first controller 3 controls the amount of oil output by the main pressure-building unit 14 based on the displacement to achieve braking of the first brake 100. Thus, redundant protection can be formed between the brake master cylinder 12 and the main pressure-building unit 14. It should be noted that in this embodiment, the output end of the main pressure-building unit 14 supplies oil to each first brake 100 at the same time.

[0075] Optionally, in this embodiment, the oil pressure of the brake master cylinder 12 is also detected by a pressure sensor 20. It can be understood that the pressure sensor 20 is communicatively connected to the first controller 3, and the pressure sensor 20 is used to send the detected pressure value to the first controller 3. On the premise that the displacement sensor 15 works normally, the pressure sensor 20 is used for redundant backup. When the displacement sensor 15 fails, the first controller 3 controls the amount of oil output by the main pressure building unit 14 based on the pressure value detected by the pressure sensor 20.

[0076] In this embodiment, the hydraulic brake module 1 also includes a simulator 19. When the master pressure-building unit 14 is functioning properly, the hydraulic fluid in the master cylinder 12 does not need to be output to the first brake 100, but is instead output only to the simulator 19. The simulator 19 then provides feedback to the brake piston of the master cylinder 12, which then acts on the brake pedal 13, providing the driver with a pedal feel. Simultaneously, the movement of the brake piston of the master cylinder 12 can be detected by the displacement sensor 15. It should be noted that when the master pressure-building unit 14 is malfunctioning, the master cylinder 12 also outputs fluid to the first brake 100.

[0077] In this embodiment, whether the master brake cylinder 12 delivers oil to the first brake 100, and whether the main pressure building unit 14 delivers oil to the first brake 100 are both achieved through control valve control. Specifically, in this embodiment, the hydraulic brake module 1 also includes a first oil circuit 161, a second oil circuit 162, a first control valve 171 and a second control valve 172. The first oil circuit 161 connects the output end of the master brake cylinder 12 and the first brake 100, the first control valve 171 is arranged in the first oil circuit 161, the second oil circuit 162 connects the main pressure building unit 14 and the first brake 100, and the second control valve 172 is arranged in the second oil circuit 162. The connection or disconnection of the first oil circuit 161 is controlled by the first control valve 171, and the connection or disconnection of the second oil circuit 162 is controlled by the second control valve 172. As Figure 1 As shown, when the first control valve 171 controls the first oil circuit 161 to be connected, and the second control valve 172 controls the second oil circuit 162 to be disconnected, the oil is driven into the first brake 100 through the brake master cylinder 12; Figure 2 As shown, when the first control valve 171 controls the first oil circuit 161 to be disconnected, and the second control valve 172 controls the second oil circuit 162 to be connected, the oil is driven into the first brake 100 through the main pressure building unit 14 .

[0078] It should be noted that a first oil circuit 161 and a second oil circuit 162 are provided for each first brake 100, and each first oil circuit 161 is provided with a first control valve 171, and each second oil circuit 162 is provided with a second control valve 172. This allows the master cylinder 12 and the master pressure-building unit 14 to deliver oil to each first brake 100 and to independently control each first brake 100. For example, the first and second control valves 171, 172 are both two-position, two-way solenoid valves, and are communicatively connected to the first controller 3. This allows the first controller 3 to simultaneously control the opening and closing states of each control valve, thereby independently controlling each first brake 100. In particular, if some first brakes 100 malfunction, the normal operation of the remaining first brakes 100 will not be affected.

[0079] Alternatively, as Figure 2 and Figure 4As shown, the hydraulic brake module 1 also includes a third oil circuit 163 and a third control valve 173 arranged in the third oil circuit 163. The first oil circuit 161 and the second oil circuit 162 are both connected to the first brake 100 through the third oil circuit 163, and the third control valve 173 is used to adjust the opening of the third oil circuit 163. When the third control valve 173 opens the third oil circuit 163, the oil from the brake master cylinder 12 or the main pressure building unit 14 can be delivered to the first brake 100, and by adjusting the opening of the third control valve 173, linear control of the oil entering the first brake 100 can be achieved. When the third control valve 173 disconnects the third oil circuit 163, the oil from the brake master cylinder 12 or the main pressure building unit 14 cannot be delivered to the first brake 100. In this embodiment, the third control valve 173 is also exemplified by a two-position two-way solenoid valve, and the third control valve 173 is communicatively connected to the first controller 3.

[0080] like Figures 1 to 4 As shown, in this embodiment, the hydraulic brake module 1 further includes a fourth oil circuit 164 connecting the first brake 100 and the fluid reservoir 11, and a fourth control valve 174 disposed in the fourth oil circuit 164. The fourth control valve 174 is used to control the connection or disconnection of the fourth oil circuit 164. When the fourth control valve 174 disconnects the fourth oil circuit 164, the oil pressure in the first brake 100 is maintained. When the fourth control valve 174 opens the fourth oil circuit 164, the oil in the first brake 100 is returned to the oil tank. By providing the fourth control valve 174, when the braking force of the first brake 100 is high, the fourth control valve 174 is momentarily opened and closed to partially drain the oil in the first brake 100, thereby reducing the braking force of the first brake 100 and preventing the wheel 300 from locking. When the first brake 100 is released, the fourth control valve 174 is kept open, allowing the entire oil in the first brake 100 to return to the fluid reservoir 11.

[0081] like Figures 1 to 5As shown, the main pressure building unit 14 includes a first motor 141, a first screw rod 142, a first nut, a first piston 144 and a first cylinder 145. Among them, the first controller 3 is electrically connected to the first motor 141, the first motor 141 is transmission-connected to the first screw rod 142, the first nut is screwed to the first screw rod 142, the first nut and the first piston 144 are fixedly connected, and the first piston 144 is slidably arranged in the first cylinder 145. It can be understood that the sliding direction of the first piston 144 coincides with the axial direction of the first screw rod 142, the first nut and the housing of the first motor 141 are slidably matched, and when the first motor 141 rotates, the first screw rod 142 rotates accordingly, and the first nut moves along the first screw rod 142, thereby driving the first piston 144 to move in the first cylinder 145. Among them, the first motor 141 can rotate forward or reverse, thereby realizing the reciprocating motion of the first piston 144; the input interface of the first cylinder body 145 is connected to the liquid storage tank 11 through a pipeline, and the output interface of the first cylinder body 145 is connected to each second oil circuit 162, which is used to supply oil to each first brake 100. The input interface and output interface of the first cylinder body 145 are arranged at intervals along the axial direction of the first piston 144. Such an arrangement can avoid mutual interference when the oil enters and outputs the first cylinder body 145.

[0082] Optionally, the main pressure-building unit 14 further includes a rotation angle sensor 146 communicatively connected to the first controller 3. The rotation angle sensor 146 is configured to detect the rotation angle of the first motor 141 and transmit the detected angle to the first controller 3. It will be appreciated that the rotation angle of the first motor 141 directly determines the displacement of the first piston 144, and the displacement of the first piston 144 directly determines the amount of oil output to the first brake 100. Therefore, the brake oil pressure of the first brake 100 can be assessed based on the detection value of the rotation angle sensor 146.

[0083] Optionally, the hydraulic brake module 1 further includes a first oil replenishment circuit 165 and a second oil replenishment circuit 166 . Both the first oil replenishment circuit 165 and the second oil replenishment circuit 166 are connected to the fluid reservoir 11 . The first oil replenishment circuit 165 is connected to the input port of the first cylinder 145 , while the second oil replenishment circuit 166 is connected to the replenishment port of the first cylinder 145 , with the replenishment port being located between the input port and the output port. The second oil replenishment circuit 166 is provided with a one-way valve 18 , which is configured to only allow fluid to flow from the fluid reservoir 11 to the first cylinder 145 . With this arrangement, both the first oil replenishment circuit 165 and the second oil replenishment circuit 166 can be used to replenish fluid into the first cylinder 145 . Specifically, the input port and the oil replenishment port can be simultaneously connected to the oil chamber of the first cylinder 145, or only the oil replenishment port can be connected to the oil chamber of the first cylinder 145. This is determined by the position of the first piston 144 in the first cylinder 145. Thus, oil can be replenished into the oil chamber of the first cylinder 145 through both the first oil replenishment passage 165 and the second oil replenishment passage 166, or only through the second oil replenishment passage 166. When the main pressure building unit 14 delivers oil to the first brake 100, if the first piston 144 begins to move from its initial position, it first passes through the input port and then the oil replenishment port. After passing through the input port, the first piston 144 moves, thereby delivering oil to the first brake 100. When it is determined that the oil in the first cylinder 145 is insufficient, the second oil circuit 162 can be disconnected by the second control valve 172, and the first motor 141 drives the first piston 144 to quickly retreat between the input interface and the oil replenishing interface, thereby generating a negative pressure in the first cylinder 145. Under the action of the negative pressure, the oil in the liquid storage tank 11 can be replenished into the first cylinder 145 through the one-way valve 18, thereby realizing the replenishment of the oil in the first cylinder 145.

[0084] In order to ensure the sealing performance between the first piston 144 and the first cylinder body 145, two leather cups 143 are further provided on the first cylinder body 145. The two leather cups 143 are respectively located on both sides of the input interface of the first cylinder body 145. During operation, the first piston 144 can be in sealing contact with the two leather cups 143 to achieve sealing of the input interface.

[0085] In this embodiment, the simulator 19's oil input port is connected to the fluid reservoir 11 via a fifth oil passage 167. A fifth control valve 175 is provided on this passage. This valve is used to control the connection and disconnection of this passage. This valve controls whether the oil in the master brake cylinder 12 is delivered to the simulator 19. The fifth control valve 175 is also exemplified as a two-position, two-way solenoid valve and is also communicatively connected to the first controller 3.

[0086] Optionally, the hydraulic brake module 1 further includes a sixth oil circuit 168. Figures 1 to 4 As shown, the sixth oil circuit 168 connects the output oil port of the simulator 19 and the liquid storage tank 11. Alternatively, as Figure 5 As shown, the sixth oil circuit 168 connects the output oil port of the simulator 19 and the input oil port of the master brake cylinder 12 , and the master brake cylinder 12 does not supply oil to the first brake 100 . At this time, the simulator 19 is decoupled.

[0087] In this embodiment, the second brake 200 adopts a mechanical brake caliper. Figures 1 to 5 As shown, the mechanical power unit 2 includes a second motor 21, a second screw 22 drivingly connected to the second motor 21, a second nut threadedly connected to the second screw 22, and a pusher 23 fixedly connected to the second nut. The second nut is slidably connected to the motor housing 24, and the pusher 23 drives the mechanical brake caliper to operate. The second motor 21 is electrically connected to the second controller 4. In this embodiment, the second controller 4 is specifically a brake controller (BCU). The second controller 4 is also connected to the displacement sensor 15. The second controller 4 controls the rotation angle of the second motor 21 by collecting the displacement of the piston of the brake master cylinder 12, thereby achieving control of the second brake 200.

[0088] In this embodiment, a mechanical power unit 2 is provided for each of the two second brakes 200. The second motor 21 of each mechanical power unit 2 is connected to the second controller 4. Thus, each second brake 200 can be controlled individually or synchronously by the second controller 4. In particular, if one of the second brakes 200 malfunctions, the normal operation of the other second brake 200 is not affected.

[0089] like Figure 6 As shown, the braking system also includes a power supply, which is used to power the first controller 3, the second controller 4, and various power-consuming units (such as motors and solenoid valves). To prevent a power failure from causing all power-consuming components to cease functioning, in this embodiment, the power supply includes a first power supply 5 and a second power supply 6. The first power supply 5 is used to power the hydraulic brake module 1 and the first controller 3; the second power supply 6 is used to power the mechanical power unit 2 and the second controller 4. Preferably, two first power supplies 5 and two second power supplies 6 are provided, so that redundant backup can be achieved between the two first power supplies 5 and the two second power supplies 6.

[0090] by Figure 1 Take the braking system shown in the figure as an example. When all components are normal, the working principle of the braking system is as follows:

[0091] 1) Before the brake pedal 13 is stepped on, the first controller 3 controls the two first control valves 171 to lose power and open the two first oil circuits 161, the fifth control valve 175 to lose power and disconnect the fifth oil circuit 167, the two second control valves 172 to lose power and disconnect the two second oil circuits 162, and the two fourth control valves 174 to lose power and disconnect the two fourth oil circuits 164.

[0092] 2) When the brake pedal 13 is stepped on, the first controller 3 controls the two first control valves 171 to energize and disconnect the two first oil circuits 161. The fifth control valve 175 is energized to connect the fifth oil circuit 167. The piston of the master cylinder 12 moves, and the oil in the master cylinder 12 is delivered to the simulator 19. The displacement sensor 15 detects the displacement and transmits it to the first controller 3 and the second controller 4. The first controller 13 determines the target rotation angle of the first motor 141 based on the displacement. The second controller 4 also determines the target rotation angle of the second motor 21 based on the displacement. The first motor 141 then starts and gradually rotates to its target angle. The two second control valves 172 are energized to open the two second oil circuits 162, and the oil is delivered to the two first brakes 100, braking the two wheels 300. The two second motors 21 rotate to their target angles, and the two second brakes 200 brake the two wheels 300.

[0093] by Figure 1 Taking the braking system shown in FIG. 1 as an example, when the main pressure-building unit 14 fails, the working principle of the braking system is as follows:

[0094] 1) Before the brake pedal 13 is stepped on, the situation is the same as above.

[0095] 2) After the brake pedal 13 is stepped on, the first controller 3 controls the two first control valves 171 to energize and disconnect the two first oil circuits 161, and the fifth control valve 175 is energized to connect to the fifth oil circuit 167. The piston of the brake master cylinder 12 moves, and the oil in the brake master cylinder 12 is transported to the simulator 19. The displacement sensor 15 detects the displacement and sends it to the second controller 4. The second controller 4 determines the target rotation angle of the second motor 21 based on the displacement, and then the two second motors 21 rotate to their target angles, and the two second brakes 200 brake the two wheels 300.

[0096] by Figure 1 Taking the braking system shown in FIG. 1 as an example, when the main pressure building unit 14 is normal but a component in one of the second oil circuits 162 fails, the working principle of the braking system is as follows:

[0097] 1) Before the brake pedal 13 is stepped on, the situation is the same as above.

[0098] 2) When the brake pedal 13 is stepped on, the first controller 3 energizes the two first control valves 171, disconnecting the two first oil circuits 161. The fifth control valve 175 energizes and connects the fifth oil circuit 167. The piston of the master cylinder 12 moves, and the oil in the master cylinder 12 is delivered to the simulator 19. The displacement sensor 15 detects the displacement and transmits it to the first controller 3 and the second controller 4. The first controller 13 determines the target rotation angle of the first motor 141 based on the displacement. The second controller 4 also determines the target rotation angle of the second motor 21 based on the displacement. The first motor 141 then starts and gradually rotates to its target angle. Only the second control valve 172 in the normal second oil circuit 162 is energized to open the second oil circuit 162, and the oil is delivered to one of the first brakes 100, braking one wheel 300. The two second motors 21 rotate to their target angles, and the two second brakes 200 brake both wheels 300.

[0099] by Figure 1 Taking the braking system shown in FIG. 1 as an example, when both mechanical power units 2 fail, the working principle of the braking system is as follows:

[0100] 1) Before the brake pedal 13 is stepped on, the situation is the same as above.

[0101] 2) After the brake pedal 13 is stepped on, the first controller 3 controls the two first control valves 171 to energize and disconnect the two first oil circuits 161, and the fifth control valve 175 is energized to connect the fifth oil circuit 167. The piston of the brake master cylinder 12 moves, and the oil in the brake master cylinder 12 is transported to the simulator 19. The displacement sensor 15 detects the displacement and sends it to the first controller 3. The first controller 13 determines the target rotation angle of the first motor 141 based on the displacement, and then the first motor 141 starts and gradually rotates to its target angle. The two second control valves 172 are energized to open the two second oil circuits 162, and the oil is transported to the two first brakes 100 to achieve braking of the two wheels 300.

[0102] by Figure 1 Taking the braking system shown in FIG. 1 as an example, when one of the mechanical power units 2 fails, the working principle of the braking system is as follows:

[0103] 1) Before the brake pedal 13 is stepped on, the situation is the same as above.

[0104] 2) When the brake pedal 13 is stepped on, the first controller 3 controls the two first control valves 171 to energize, disconnecting the two first oil circuits 161. The fifth control valve 175 is energized to connect the fifth oil circuit 167. The piston of the master cylinder 12 moves, and the oil in the master cylinder 12 is delivered to the simulator 19. The displacement sensor 15 detects the displacement and transmits it to the first controller 3. The first controller 13 determines the target rotation angle of the first motor 141 based on the displacement. The second controller 4 also determines the target rotation angle of the second motor 21 in the normal mechanical power unit 2 based on the displacement. The first motor 141 then starts and gradually rotates to its target angle. The two second control valves 172 are energized to open the two second oil circuits 162, and the oil is delivered to the two first brakes 100, braking the two wheels 300. The second motor 21 in the normal mechanical power unit 2 starts and gradually rotates to its target angle. This second motor 21 drives a second brake 200 to brake a single wheel 300.

[0105] This embodiment also provides a method for controlling a braking system, which is executed by the above-mentioned braking system.

[0106] Specifically, if Figure 7 As shown, the control method of the braking system includes the following steps.

[0107] S100: Obtaining a braking request of the vehicle.

[0108] The vehicle's braking request can be obtained in a variety of ways. For example, the vehicle's braking request can be detected by a sensor installed on the brake pedal 13. When the brake pedal 13 is touched, the sensor detects the movement of the brake pedal 13 and sends a signal to the first controller 3, thereby determining the braking request. Alternatively, the braking request can be determined by detecting the displacement of the piston of the brake master cylinder 12 by a displacement sensor 15 installed on the brake master cylinder 12. Alternatively, the braking request can be determined based on the distance between the obstacle in front of the vehicle and the current position of the vehicle and the current speed of the vehicle.

[0109] S200: Obtaining the total required braking torque of the vehicle.

[0110] Specifically, the rotation angle of the brake pedal 13 can be obtained; based on this rotation angle, the total required braking torque is determined. This embodiment is not limited to determining the total required braking torque based on the rotation angle of the brake pedal 13; any parameter linearly related to the rotation angle of the brake pedal 13 can be used. For example, the displacement of the piston in the master cylinder 12 or the actual oil pressure in the master cylinder 12 can be used.

[0111] A rotation angle-total required braking torque relationship chart may be pre-set in the first controller 3. The corresponding total required braking torque may be queried from the rotation angle-total required braking torque relationship chart according to the rotation angle.

[0112] S300: Compare the total required braking torque of the vehicle with the maximum recovery torque that can be provided by the energy recovery system.

[0113] Among them, the energy recovery system is an existing technology. For example, the previous patent with application number CN201721854441.3 discloses a generator assembly that can be used for braking energy recovery.

[0114] In this embodiment, if the total required braking torque of the vehicle is not greater than the maximum recovery torque, then S301 is executed; if the total required braking torque of the vehicle is greater than the maximum recovery torque, then S400 is executed;

[0115] S301: The energy recovery system provides a recovery torque.

[0116] S400: The energy recovery system provides the maximum recovery torque, and the braking system provides the braking torque. Braking torque = total required braking torque - maximum recovery torque.

[0117] The maximum regenerative torque provided by the energy recovery system is applied to the drive shaft, while the braking torque provided by the brake system is preferentially applied to the non-drive shaft. Specifically, when the braking torque is less than the maximum set torque that can be applied to the non-drive shaft, the brake system applies the entire braking torque to the non-drive shaft. When the braking torque is less than the maximum set torque that can be applied to the non-drive shaft, the brake system applies the maximum set torque to the non-drive shaft and applies the remaining torque to the drive shaft.

[0118] S500: Obtain the slip rate of each wheel 300 in real time.

[0119] When a tire generates traction or braking force, relative motion occurs between the tire and the ground. The slip ratio is the proportion of slip in the motion of a wheel 300. The slip ratio of each wheel 300 can be calculated by detecting the vehicle's speed using a speed sensor and the rotational speed of each wheel 300 using a rotational speed sensor.

[0120] S600: Determine whether the slip ratio of at least one wheel 300 is greater than a first set value.

[0121] S700: The maximum regenerative torque provided by the energy recovery system is reduced to zero, and the braking torque provided by the braking system is increased.

[0122] In step S600, when the slip rate of wheel 300 is greater than the first set value, it indicates that the vehicle should be slowed down or stopped as soon as possible for the best safety for the driver. Because the energy recovery efficiency of the energy recovery system is lower than that of the direct braking system, and the braking torque provided by the braking system is not the total required torque, this affects the braking effect. This can increase the time it takes for the vehicle to stop from moving, which can easily lead to accidents. The first set value can be set as needed.

[0123] In step S700, by reducing the maximum recovery torque provided by the energy recovery system to zero, the influence of the energy recovery system on the braking effect can be eliminated in time, and the braking torque provided by the braking system can be increased in time to help the vehicle slow down as quickly as possible.

[0124] Among them, when increasing the braking torque of the braking system, when the total required braking torque is within the permitted range, the braking torque of the braking system can be directly increased to the total required braking torque; when the total required braking torque is outside the permitted range, the braking torque of the braking system can be directly increased to the upper limit of the permitted range.

[0125] Specifically, the braking torque provided by the lifting brake system includes:

[0126] S701: If the total required braking torque does not exceed the set braking torque upper limit threshold; calculate the shared torque of each brake, shared torque = total required braking torque / (total number of first brakes + total number of second brakes).

[0127] S702: If the total required braking torque exceeds the braking torque upper limit threshold, calculate the shared torque of each brake, shared torque = braking torque upper limit threshold / (total number of first brakes + total number of second brakes).

[0128] S703: The hydraulic brake module 1 drives each first brake 100 to output a shared torque;

[0129] S704: The plurality of mechanical power units 2 drive the respective second brakes 200 in a one-to-one correspondence to output shared torque.

[0130] Among them, the upper limit threshold of the braking torque can be set as needed. When the hydraulic brake module 1 drives each first brake 100 to output the shared torque, according to the preset relationship chart between the shared torque and the first motor rotation angle, the first motor rotation angle corresponding to the shared torque is queried from the relationship chart, and then the first motor 141 is controlled to rotate to the first motor rotation angle. When the mechanical power unit 2 drives the second brake 200 to output the shared torque, it can be based on the preset relationship chart between the shared torque and the second motor rotation angle in advance, and the second motor 21 is controlled to rotate to the second motor rotation angle. Among them, the relationship chart between the shared torque and the first motor rotation angle, and the relationship chart between the shared torque and the second motor rotation angle can be obtained based on a large number of preliminary tests.

[0131] S800 : Adjusting the braking torque provided by the braking system to each wheel 300 based on the slip ratio of each wheel 300 .

[0132] Since the braking system can independently control the braking torque of the brake on each wheel 300, it is possible to independently adjust the braking torque according to the slip rate of each wheel 300 to keep the vehicle body balanced.

[0133] Specifically, adjusting the braking torque provided by the braking system to each wheel 300 based on the slip ratio of each wheel 300 includes:

[0134] S801: Compare the slip ratio of the wheel 300 with a second set value.

[0135] If the slip ratio of the wheel 300 is greater than the second set value, S802 is executed; if the slip ratio of the wheel 300 is less than the second set value, S803 is executed.

[0136] S802 : Reduce the braking torque provided by the braking system to the wheel 300 .

[0137] S803: Increase the braking torque provided by the braking system to the wheel 300.

[0138] The second set value is greater than the first set value and can be set as needed. It is understood that when the slip rate of wheel 300 is greater than the second set value, it indicates that wheel 300 is locked and the braking torque needs to be appropriately reduced to allow wheel 300 to rotate properly and maintain vehicle body balance.

[0139] Specifically, reducing the braking torque provided by the braking system to the wheel 300 includes:

[0140] The braking torque of the wheel 300 is gradually reduced in steps of the second set torque until the slip rate of the wheel 300 is less than the second set value. The second set torque can be set as needed.

[0141] When the slip rate of wheel 300 is greater than the second set value, it indicates that the braking torque of wheel 300 can still be increased and wheel 300 has not been locked. It is necessary to continue to increase the braking torque of wheel 300 so that wheel 300 can obtain the maximum braking torque to ensure the braking effect.

[0142] Specifically, increasing the braking torque provided by the braking system to the wheel 300 includes:

[0143] The braking torque of the wheel 300 is gradually increased with the first set torque as a step size until the slip rate of the wheel 300 is not less than the second set value.

[0144] In this embodiment, the first controller 300 is preset with a map 1 of the first set torque and the first motor rotation angle, a map 2 of the first set torque and the second motor rotation angle, a map 3 of the second set torque and the second motor rotation angle, and a map 4 of the second set torque and the opening time of the fourth control valve 174 each time.

[0145] Taking increasing the braking torque provided by the braking system to the wheel 300 as an example, the first motor rotation angle corresponding to the first set torque is retrieved from map 1. The first controller 3 controls the first motor 141 to rotate by the first motor rotation angle each time, causing the first brake 100 to increase the first set torque to the wheel 300 each time. Based on the first set torque, the second motor rotation angle corresponding to the second set torque is retrieved from map 2. The second controller 4 interacts with the first controller 3 to obtain the second motor rotation angle and controls the second motor 21 to rotate by the second motor rotation angle each time, causing the second brake 200 to increase the first set torque to the wheel 300 each time.

[0146] Taking the reduction of the braking torque provided by the braking system to the wheel 300 as an example, based on the second set torque, the corresponding second motor rotation angle is retrieved from map 3. The second controller 4 interacts with the first controller 3 to obtain this second motor rotation angle and controls the second motor 21 to rotate by this second motor rotation angle each time, thereby enabling the second brake 200 to reduce the second set torque provided to the wheel 300. Based on the second set torque, the corresponding opening time of the fourth control valve 174 is retrieved from map 4. The first controller 3 controls the fourth control valve 174 to open and close at this time each time, thereby enabling the first brake 100 to reduce the second set torque provided to the wheel 300 each time. During the opening and closing of the fourth control valve 174, the second control valve 172 remains closed.

[0147] Optionally, when adjusting the braking torque provided by the braking system to each wheel 300 based on the slip ratio of each wheel 300, the control method of the braking system further simultaneously performs the following steps:

[0148] S900 : Acquire the oil level of the first cylinder 145 of the main pressure building unit 14 in real time.

[0149] The amount of oil in the first cylinder 145 may be detected by a liquid level sensor.

[0150] S1000: Compare the oil volume with the set oil volume.

[0151] If the oil amount is less than the set oil amount, execute S1100; if the oil amount is not less than the set oil amount, execute S900.

[0152] The set oil volume can be set as needed. Since the main pressure-building unit 14 needs to frequently output oil during the process of adjusting the braking torque of the wheel 300 based on the slip ratio, this can cause the oil in the first cylinder 145 to gradually decrease over time. When the oil volume is determined to be less than the set oil volume, it indicates that the oil in the first cylinder 145 is insufficient.

[0153] S1100 : The second control valve 172 is closed for a set time and then opened. During the set time of closing the second control valve 172 , the first piston 144 of the main pressure building unit 14 is controlled to move between the oil replenishment interface and the input interface.

[0154] When the second control valve 172 is closed, the communication between the first cylinder 145 and the first brake 100 is disconnected. Driven by the first motor 141, the first piston 144 quickly retracts to between the oil replenishment port and the input port. This generates negative pressure in the first cylinder 145. Driven by this negative pressure, the oil in the reservoir 11 is replenished into the first cylinder 145 via the second oil replenishment passage 166 and the one-way valve 18 to meet the oil demand of the first cylinder 145. While the first cylinder 145 is replenishing oil, the fourth control valve 174 is closed.

[0155] After step S1100 , step S900 may be re-executed.

[0156] Obviously, the above embodiments of the present invention are merely examples for the purpose of clearly illustrating the present invention, and are not intended to limit the embodiments of the present invention. Those skilled in the art will appreciate that other variations or modifications can be made based on the above description. It is not necessary and impossible to enumerate all embodiments here. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention shall be included within the scope of protection of the claims of the present invention.

Claims

1. A method for controlling a braking system, characterized in that: The control method of the braking system includes: Get the vehicle's braking request; Obtaining the total required braking torque of the vehicle; Determining that the total required braking torque of the vehicle is greater than the maximum regenerative torque that the energy regeneration system can provide; The energy recovery system provides the maximum recovery torque, and the braking system provides the braking torque. The braking torque = the total required braking torque - the maximum recovery torque; Get the slip rate of each wheel in real time; determining that a slip ratio of at least one of the wheels is greater than a first set value; The maximum regenerative torque provided by the energy recovery system is reduced to zero, and the braking torque provided by the braking system is increased; adjusting the braking torque provided by the braking system to each of the wheels based on the slip ratio of each wheel; The braking system includes a hydraulic brake module, a plurality of first brakes, a plurality of mechanical power units, and a plurality of second brakes; the hydraulic brake module is capable of hydraulically driving the plurality of first brakes, and the plurality of mechanical power units are capable of mechanically driving the plurality of second brakes in a one-to-one correspondence; a portion of the wheels are installed with the first brakes, and another portion of the wheels are installed with the second brakes; The braking torque provided by the lifting brake system includes: If the total required braking torque does not exceed the set braking torque upper limit threshold; Calculate the shared torque of each brake: shared torque = total required braking torque / (total number of first brakes + total number of second brakes); If the total required braking torque exceeds the braking torque upper limit threshold; Calculate the shared torque of each brake, shared torque = braking torque upper limit threshold / (total number of first brakes + total number of second brakes); The hydraulic brake module drives each of the first brakes to output the shared torque; A plurality of mechanical power units drive the second brakes in a one-to-one correspondence to output the shared torque; The hydraulic brake module includes a fluid reservoir, a brake master cylinder and a main pressure building unit, both of which are used to output fluid to each of the first brakes, a first control valve for controlling the connection or disconnection between the brake master cylinder and the first brake, and a second control valve for controlling the connection or disconnection between the brake master cylinder and the first brake. The main pressure building unit has a first oil replenishment circuit and a second oil replenishment circuit, the first oil replenishment circuit connecting the fluid reservoir and the input interface of the cylinder body of the main pressure building unit, the second oil replenishment circuit connecting the fluid reservoir and the oil replenishment interface of the cylinder body of the main pressure building unit, the second oil replenishment circuit is provided with a one-way valve that only allows fluid to flow from the fluid reservoir to the cylinder body of the main pressure building unit, and the oil replenishment interface is located between the input interface and the output interface of the main pressure building unit; When adjusting the braking torque provided by the braking system to each of the wheels based on the slip ratio of each wheel; Real-time acquisition of the amount of oil in the first cylinder of the main pressure-building unit; When it is determined that the oil volume is less than the set oil volume, the second control valve is closed for a set time and then opened, and within the set time of closing the second control valve, the piston of the main pressure building unit is controlled to move between the oil replenishment interface and the input interface.

2. The method for controlling a braking system according to claim 1, wherein: If the total required braking torque of the vehicle is not greater than the maximum regenerative torque; Only the energy recovery system provides regenerative torque.

3. The control method of the braking system according to claim 1, characterized in that: Obtaining the total required braking torque of the vehicle includes: Get the rotation angle of the brake pedal; A total required braking torque is determined based on the rotational angle.

4. The method for controlling a braking system according to claim 1, wherein: Adjusting the braking torque provided by the braking system to each wheel based on the slip ratio of each wheel includes: If the slip rate of the wheel is greater than a second set value; the second set value is greater than the first set value; The braking torque provided by the braking system to the wheel is reduced.

5. The method for controlling a braking system according to claim 4, wherein: If the slip ratio of the wheel is less than the second set value; The braking torque provided by the braking system to the wheels is increased.

6. The method for controlling a braking system according to claim 5, wherein: Increasing the braking torque provided by the braking system to the wheel includes: The braking torque of the wheel is gradually increased with a first set torque as a step size until the slip rate of the wheel is not less than the second set value.

7. The method for controlling a braking system according to claim 4, wherein: Reducing the braking torque provided by the braking system to the wheel includes: The braking torque of the wheel is gradually reduced in steps of the second set torque until the slip rate of the wheel is less than the second set value.

8. A braking system, characterized in that: A control method for a braking system used to implement any one of claims 1-7.

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