Control methods of vehicle EPB system and vehicle

Abstract

This invention relates to the field of vehicle technology, specifically providing a control method for a vehicle EPB system, aiming to solve the problem that existing vehicles struggle to brake according to different deceleration requirements when malfunctions or hydraulic braking modules fail. To this end, the vehicle EPB system of this invention includes a braking mechanism configured to clamp and release the vehicle's wheels; the control method includes: acquiring the vehicle's deceleration request; determining a target clamping force based on the acquired deceleration request; and controlling the braking mechanism to incrementally increase the clamping force until the clamping force reaches the target clamping force. The control method of this invention can brake the vehicle regardless of whether a malfunction occurs or the hydraulic braking module fails, with good braking effect, thus improving vehicle safety.

Description

Technical Field

[0001] This invention relates to the field of vehicle technology, specifically providing a control method for a vehicle EPB system and a vehicle. Background Technology

[0002] The parking brake system is an essential part of a vehicle. It enables the vehicle to slow down or stop. EPB is an abbreviation for Electrical Park Brake, which replaces the traditional mechanical lever and tire cable. It provides better assistance to the driver, is safer than the traditional lever handbrake, and its braking effect is not affected by the driver's force. It turns the traditional lever handbrake into an easily accessible button, making it convenient for the driver to use and improving the driving experience.

[0003] However, as autonomous driving places increasingly higher demands on actuators, in braking system solutions without redundant braking modules, if the vehicle malfunctions, or if the hydraulic braking module partially or completely fails, the existing EPB system will struggle to perform braking operations according to different vehicle deceleration requirements.

[0004] In summary, existing vehicles are unable to brake according to different driving deceleration requirements when malfunctions occur or the hydraulic braking module fails.

[0005] Accordingly, there is a need in the art for a new control method for vehicle EPB systems to solve the above problems. Summary of the Invention

[0006] The present invention aims to solve the above-mentioned technical problems, namely, to solve the problem that existing vehicles are unable to perform braking operations according to different driving deceleration requirements when malfunctions or hydraulic braking modules fail.

[0007] In a first aspect, the present invention provides a control method for a vehicle EPB system, the vehicle EPB system including a braking mechanism configured to clamp and release the wheels of the vehicle;

[0008] The control method includes:

[0009] Obtain the deceleration request from the vehicle;

[0010] Determine the target clamping force based on the obtained deceleration request;

[0011] The braking mechanism is controlled to increase clamping force until the clamping force of the braking mechanism reaches the target clamping force.

[0012] In the preferred embodiment of the above control method, the step of "controlling the braking mechanism to perform incremental clamping until the clamping force of the braking mechanism reaches the target clamping force" specifically includes:

[0013] The braking mechanism is controlled to add clamping force corresponding to a first preset deceleration at preset time intervals until the clamping force of the braking mechanism reaches the target clamping force.

[0014] In a preferred embodiment of the above control method, the control method further includes:

[0015] During the incremental clamping process of the braking mechanism, the deceleration of the wheel and the slip ratio of the wheel are obtained;

[0016] Based on the obtained deceleration and slip ratio of the wheel, the braking mechanism is controlled to enter dynamic control;

[0017] The dynamic control refers to the switching of the braking mechanism between decreasing release and increasing clamping operations.

[0018] or,

[0019] The braking mechanism performs decreasing release or increasing clamping operation while maintaining the target clamping force.

[0020] In the preferred embodiment of the above control method, the step of "controlling the braking mechanism to enter dynamic control based on the obtained deceleration and slip ratio of the wheel" specifically includes:

[0021] If the deceleration of the wheel is greater than the second preset deceleration or the slip ratio of the wheel is greater than the first preset slip ratio, then the braking mechanism is controlled to perform a decreasing release operation; and / or

[0022] If the slip ratio of the wheel is less than the second preset slip ratio, the braking mechanism is controlled to perform incremental clamping.

[0023] Wherein, the first preset slip ratio is greater than the second preset slip ratio.

[0024] In the preferred embodiment of the above control method, the step of "controlling the braking mechanism to enter dynamic control based on the obtained deceleration and slip ratio of the wheel" further includes:

[0025] When the braking mechanism is released in a decreasing manner, if the slip ratio is less than or equal to the first preset slip ratio and the deceleration of the wheel is less than or equal to the second preset deceleration, then when the clamping force of the braking mechanism reaches the target clamping force, the clamping force of the braking mechanism is controlled to be maintained at the target clamping force.

[0026] In the preferred embodiment of the above control method, the step of "controlling the braking mechanism to enter dynamic control based on the obtained deceleration and slip ratio of the wheel" further includes:

[0027] While maintaining the target clamping force, if the slip ratio is greater than the first preset slip ratio or the deceleration of the wheel is greater than the second preset deceleration, the braking mechanism is controlled to perform a decreasing release operation again.

[0028] In the preferred embodiment of the above control method, the step of "controlling the braking mechanism to enter dynamic control based on the obtained deceleration and slip ratio of the wheel" further includes:

[0029] When the braking mechanism performs incremental clamping, if the slip ratio is less than or equal to the first preset slip ratio and the deceleration of the wheel is less than or equal to the second preset deceleration, then when the clamping force of the braking mechanism reaches the target clamping force, the clamping force of the braking mechanism is controlled to be maintained at the target clamping force.

[0030] In the preferred embodiment of the above control method, the step of "controlling the braking mechanism to enter dynamic control based on the obtained deceleration and slip ratio of the wheel" further includes:

[0031] If the slip ratio is less than the second preset slip ratio while maintaining the target clamping force, the braking mechanism is controlled to perform incremental clamping again.

[0032] In the preferred embodiment of the above control method, the decremental release of the braking mechanism specifically includes:

[0033] The braking mechanism is controlled to release a preset pitch in each preset step.

[0034] In a preferred embodiment of the above control method, the control method further includes:

[0035] When the braking mechanism is disengaged from the dynamic control, the position of the brake piston within the braking mechanism is obtained;

[0036] Determine whether the vehicle has received a parking brake request;

[0037] Based on the position of the brake piston in the braking mechanism and the determination result of whether the vehicle has received a parking brake request, the movement of the brake piston is controlled accordingly.

[0038] In the preferred embodiment of the above control method, the specific steps of "controlling the movement of the brake piston accordingly based on the determination result of the brake piston position of the braking mechanism and whether the vehicle has received a parking brake request" include:

[0039] If the vehicle receives a parking brake request and the brake piston is in the non-braking position, the brake piston is controlled to move to the braking position.

[0040] In the preferred embodiment of the above control method, the specific steps of "controlling the movement of the brake piston accordingly based on the determination result of the brake piston position of the braking mechanism and whether the vehicle has received a parking brake request" include:

[0041] If the vehicle does not receive a parking brake request and the brake piston is not in its initial position, then the brake piston is controlled to move to its initial position.

[0042] In a second aspect, the present invention also provides a vehicle including a controller configured to perform the control method described in any of the preferred embodiments above.

[0043] When the above technical solution is adopted, the control method of the present invention can determine different target clamping forces according to different vehicle deceleration requests; and increase the clamping force by controlling the braking mechanism until the clamping force of the braking mechanism reaches the target clamping force. Even after the vehicle malfunctions or the hydraulic braking module fails, the vehicle can still be braked with good braking effect, thus improving vehicle safety.

[0044] Furthermore, during the incremental clamping process of the braking mechanism, the control method of the present invention controls the braking mechanism to enter dynamic control based on the obtained wheel deceleration and slip ratio. Dynamic control enables the vehicle to avoid wheel lock-up while ensuring braking effect.

[0045] Furthermore, in the case where the braking mechanism is out of dynamic control, the control method of the present invention controls the movement of the braking piston according to the judgment result of the position of the braking piston of the braking mechanism and whether the vehicle has received a parking brake request. When the vehicle is in motion, if no parking brake request is received, the braking piston is controlled to move to the initial position to prevent the braking mechanism from clamping the wheel, prevent the braking mechanism from affecting the vehicle's driving speed, and avoid wear of parts, thus extending service life. When the vehicle is static and a parking brake request is received, the braking piston is controlled to move to the braking position, so that the braking mechanism clamps the wheel, preventing the wheel from moving, preventing the vehicle from rolling, and improving safety.

[0046] Solution 1. A control method for a vehicle EPB system, characterized in that the vehicle EPB system includes a braking mechanism, the braking mechanism being configured to clamp and release the wheels of the vehicle;

[0047] The control method includes:

[0048] Obtain the deceleration request from the vehicle;

[0049] Determine the target clamping force based on the obtained deceleration request;

[0050] The braking mechanism is controlled to increase clamping force until the clamping force of the braking mechanism reaches the target clamping force.

[0051] Scheme 2. The control method according to Scheme 1, characterized in that the step of "controlling the braking mechanism to perform incremental clamping until the clamping force of the braking mechanism reaches the target clamping force" specifically includes:

[0052] The braking mechanism is controlled to add clamping force corresponding to a first preset deceleration at preset time intervals until the clamping force of the braking mechanism reaches the target clamping force.

[0053] Option 3. The control method according to Option 1, characterized in that the control method further includes:

[0054] During the incremental clamping process of the braking mechanism, the deceleration of the wheel and the slip ratio of the wheel are obtained;

[0055] Based on the obtained deceleration and slip ratio of the wheel, the braking mechanism is controlled to enter dynamic control;

[0056] The dynamic control refers to the switching of the braking mechanism between decreasing release and increasing clamping operations.

[0057] or,

[0058] The braking mechanism performs decreasing release or increasing clamping operation while maintaining the target clamping force.

[0059] Scheme 4. The control method according to Scheme 3, characterized in that the step of "controlling the braking mechanism to enter dynamic control based on the obtained deceleration and slip ratio of the wheel" specifically includes:

[0060] If the deceleration of the wheel is greater than the second preset deceleration or the slip ratio of the wheel is greater than the first preset slip ratio, then the braking mechanism is controlled to perform a decreasing release operation; and / or

[0061] If the slip ratio of the wheel is less than the second preset slip ratio, the braking mechanism is controlled to perform incremental clamping.

[0062] Wherein, the first preset slip ratio is greater than the second preset slip ratio.

[0063] Scheme 5. The control method according to Scheme 4, characterized in that the step of "controlling the braking mechanism to enter dynamic control based on the obtained deceleration and slip ratio of the wheel" further includes:

[0064] When the braking mechanism is released in a decreasing manner, if the slip ratio is less than or equal to the first preset slip ratio and the deceleration of the wheel is less than or equal to the second preset deceleration, then when the clamping force of the braking mechanism reaches the target clamping force, the clamping force of the braking mechanism is controlled to be maintained at the target clamping force.

[0065] Scheme 6. The control method according to Scheme 5, characterized in that the step of "controlling the braking mechanism to enter dynamic control based on the obtained deceleration and slip ratio of the wheel" further includes:

[0066] While maintaining the target clamping force, if the slip ratio is greater than the first preset slip ratio or the deceleration of the wheel is greater than the second preset deceleration, the braking mechanism is controlled to perform a decreasing release operation again.

[0067] Scheme 7. The control method according to Scheme 4, characterized in that the step of "controlling the braking mechanism to enter dynamic control based on the obtained deceleration and slip ratio of the wheel" further includes:

[0068] When the braking mechanism performs incremental clamping, if the slip ratio is less than or equal to the first preset slip ratio and the deceleration of the wheel is less than or equal to the second preset deceleration, then when the clamping force of the braking mechanism reaches the target clamping force, the clamping force of the braking mechanism is controlled to be maintained at the target clamping force.

[0069] Scheme 8. The control method according to Scheme 7, characterized in that the step of "controlling the braking mechanism to enter dynamic control according to the obtained deceleration and slip ratio of the wheel" further includes:

[0070] If the slip ratio is less than the second preset slip ratio while maintaining the target clamping force, the braking mechanism is controlled to perform incremental clamping again.

[0071] Option 9. The control method according to any one of Options 4 to 8, characterized in that the decremental release of the braking mechanism specifically includes:

[0072] The braking mechanism is controlled to release a preset pitch in each preset step.

[0073] Option 10. The control method according to any one of Options 4 to 8, characterized in that the control method further includes:

[0074] When the braking mechanism is disengaged from the dynamic control, the position of the brake piston within the braking mechanism is obtained;

[0075] Determine whether the vehicle has received a parking brake request;

[0076] Based on the position of the brake piston in the braking mechanism and the determination result of whether the vehicle has received a parking brake request, the movement of the brake piston is controlled accordingly.

[0077] Solution 11. The control method according to Solution 10, characterized in that the specific steps of "controlling the movement of the brake piston accordingly based on the determination result of the brake piston position of the braking mechanism and whether the vehicle has received a parking brake request" include:

[0078] If the vehicle receives a parking brake request and the brake piston is in the non-braking position, the brake piston is controlled to move to the braking position.

[0079] Scheme 12. The control method according to Scheme 10, characterized in that the specific steps of "controlling the movement of the brake piston accordingly based on the determination result of the brake piston position of the braking mechanism and whether the vehicle has received a parking brake request" include:

[0080] If the vehicle does not receive a parking brake request and the brake piston is not in its initial position, then the brake piston is controlled to move to its initial position.

[0081] Option 13. A vehicle, comprising a controller, characterized in that the controller is configured to perform the control method described in any one of Options 1 to 12 above. Attached Figure Description

[0082] The preferred embodiments of the present invention are described below with reference to the accompanying drawings, in which:

[0083] Figure 1 This is a flowchart of the main steps of the control method for the vehicle EPB system of the present invention;

[0084] Figure 2 This is a detailed flowchart of the control method for the vehicle EPB system of the present invention;

[0085] Figure 3 It is a comparison chart of the first type of uniform increase and the first type of progressive increase;

[0086] Figure 4 This is a comparison chart of the second type of uniform increase and the second type of progressive increase. Detailed Implementation

[0087] Preferred embodiments of the present invention will now be described with reference to the accompanying drawings. Those skilled in the art should understand that these embodiments are merely illustrative of the technical principles of the invention and are not intended to limit the scope of protection of the invention. For example, the present invention does not impose any restrictions on the specific type of vehicle. Those skilled in the art can define the specific type of vehicle according to actual usage needs; for example, the vehicle can be a gasoline vehicle, an electric vehicle, a sedan, or an SUV, and this is not restrictive. Those skilled in the art can make adjustments as needed to adapt to specific application scenarios.

[0088] It should be noted that in the description of this invention, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0089] The vehicle EPB system of the present invention includes a braking mechanism and an EPB control module. The EPB control module is configured to control the operation of the braking mechanism, and the braking mechanism is configured to clamp and release the wheels of the vehicle.

[0090] In a preferred embodiment, the braking mechanism includes a drive motor, a screw, a sleeve, a brake piston, and a brake caliper. The screw and the sleeve are connected. The drive motor drives the screw to rotate forward, causing the sleeve to move forward, which in turn causes the brake piston to move from its initial position to its braking position. The brake piston drives the brake caliper to clamp the brake disc, thereby generating a large frictional force to decelerate or stop the vehicle. The drive motor drives the screw to rotate in the opposite direction, causing the sleeve to retract backward, which in turn causes the brake piston to move from its non-initial position to its initial position, thereby reducing the braking force. When the brake piston moves from its initial position to its braking position, the braking mechanism is in a clamped state; when the brake piston moves from its braking position to its initial position, the braking mechanism is in a released state.

[0091] See next. Figure 1 The main steps of the vehicle EPB system control method of the present invention include the following:

[0092] Step S1: Obtain the vehicle's deceleration request;

[0093] Step S2: Determine the target clamping force based on the obtained deceleration request;

[0094] Step S3: Control the braking mechanism to increase the clamping force until the clamping force of the braking mechanism reaches the target clamping force.

[0095] In step S1, a deceleration request for the vehicle is obtained. This request can be issued by the driver or automatically generated by the EPB system or the vehicle's control components when the vehicle is in intelligent driving or autonomous driving mode. The deceleration request is the overall deceleration value of the vehicle. The deceleration request is transmitted to the EPB control module. The deceleration request can be 0.1g, 0.2g, or 0.3g, but this is not a limitation. The specific value of the deceleration request can also be 0.05g, 0.15g, 0.25g, or other values. Those skilled in the art can set it according to the actual situation.

[0096] Further, after obtaining the vehicle's deceleration request in step S1, the process proceeds to step S2. In step S2, different target clamping forces are determined based on different deceleration requests. This can be achieved by storing a one-to-one correspondence between different deceleration requests and different target clamping forces within the EPB control module, or by setting up a separate calculation module that can calculate the corresponding target clamping force based on different deceleration requests. Alternatively, a separate determination module can be set up that stores a one-to-one correspondence between different deceleration requests and different target clamping forces. When a deceleration request is obtained, it is transmitted to the determination module. After the determination module determines the target clamping force, it transmits the information to the EPB control module.

[0097] Those skilled in the art will understand that, due to differences in vehicle type, overall structure, or weight, the target clamping force corresponding to the same deceleration request may differ for different vehicles. This is not limited here, and those skilled in the art may set it according to the actual situation.

[0098] Furthermore, in step S3, based on the target clamping force determined in step S2, the EPB control module controls the braking mechanism to perform incremental clamping until the clamping force of the braking mechanism reaches the target clamping force.

[0099] After receiving a deceleration request from the vehicle, the braking mechanism clamps the rear wheels of the vehicle.

[0100] See Figure 3Specifically, the incremental clamping is achieved by adding the clamping force corresponding to the first preset deceleration at preset time intervals. For example, if the deceleration request is 0.3g, the preset time is 0.5s, and the first preset deceleration is 0.1g, in the initial state upon receiving the deceleration request, i.e., at 0s, the clamping force of the braking mechanism is 0. Afterward, the braking mechanism begins to uniformly increase the clamping force. At 0.5s, the clamping force of the braking mechanism is controlled to reach the clamping force corresponding to 0.1g; at 1s, the clamping force of the braking mechanism is controlled to reach the clamping force corresponding to 0.2g; at 1.5s, the clamping force of the braking mechanism is controlled to reach the clamping force corresponding to 0.3g; and after 1.5s, the clamping force of the braking mechanism is controlled to remain at 0. In summary, within the time interval of 0s-0.5s, the clamping force of the braking mechanism increased by 0.1g, changing from 0 to 0.1g. Within the time interval of 0.5s-1s, the clamping force of the braking mechanism increased by 0.1g, changing from 0.1g to 0.2g. Within the time interval of 1s-1.5s, the clamping force of the braking mechanism increased by 0.1g, changing from 0.2g to 0.3g. In general, the clamping force increased uniformly by 0.1g every 0.5s, and the clamping force increased by 1 times the clamping force corresponding to the first preset deceleration every 0.5s.

[0101] Continue reading Figure 3 Incremental clamping can also involve progressively increasing the clamping force corresponding to a first preset deceleration at preset time intervals. For example, if the deceleration request is 0.3g, the preset time is 0.5s, and the first preset deceleration is 0.1g, in the initial state upon receiving the deceleration request, i.e., at 0s, the clamping force of the braking mechanism is 0. Then, the braking mechanism begins to progressively increase the clamping force, controlling the clamping force to reach the clamping force corresponding to 0.1g at 0.5s, and controlling the clamping force to reach the clamping force corresponding to 0.3g at 1s. In summary... Within the duration of 0s-0.5s, the braking mechanism increases the clamping force corresponding to 0.1g, which is equivalent to doubling the clamping force corresponding to the first preset deceleration. The clamping force of the braking mechanism changes from 0 to the clamping force corresponding to 0.1g. Within the duration of 0.5s-1s, the braking mechanism increases the clamping force corresponding to 0.2g, which is equivalent to doubling the clamping force corresponding to the first preset deceleration. The clamping force of the braking mechanism changes from 0.1g to the clamping force corresponding to 0.3g. In summary, at 0.5s and 1s, the wheel deceleration is 0.1g and 0.3g, respectively.

[0102] Continue reading Figure 3In a progressively increasing manner, at 1.5s, the clamping force of the braking mechanism reaches the clamping force corresponding to 0.6g. Within a time span of 1s-1.5s, the clamping force of the braking mechanism changes from 0.3g to the clamping force corresponding to 0.6g, that is, the clamping force corresponding to the first preset deceleration is increased by 3 times. If the deceleration request is 0.6g, the control will be performed according to the above control. If the deceleration request is 0.3g, the clamping force of the braking mechanism will be controlled to maintain the clamping force corresponding to 0.3g after 1s.

[0103] See next. Figure 4 In another preferred embodiment, at each preset time interval, a clamping force corresponding to a first preset deceleration is superimposed in each time step. Figure 4 In the diagram, the solid line segment represents the clamping force, while the dashed line segment controls the clamping force to remain constant. For example, the deceleration request is 0.3g, the preset duration is 0.5s, the first preset deceleration is 0.1g, and the time step is 0.5s.

[0104] The uniformly increasing control method is as follows: In the initial state upon receiving the deceleration request, i.e., the clamping force of the braking mechanism is 0 at 0s, the braking mechanism then begins to uniformly increase the clamping force. The first time step is 0-0.5s, during which the clamping force of the braking mechanism is controlled to reach the clamping force corresponding to 0.1g. The first preset time is 0.5s-0.1s, during which the clamping force is controlled to be maintained at the clamping force corresponding to 0.1g. The second time step is 1s-1.5s, during which the clamping force is controlled to reach the clamping force corresponding to 0.2g. The second preset time is 1.5s-2s, during which the clamping force is controlled to be maintained at the clamping force corresponding to 0.2g. The third time step is 2s-2.5s, during which the clamping force is controlled to reach the clamping force corresponding to 0.3g.

[0105] The progressively increasing control method is as follows: Upon receiving a deceleration request, in the initial state (i.e., at time 0s), the clamping force of the braking mechanism is 0. Then, the braking mechanism progressively increases the clamping force. The first time step is 0s-0.5s, during which the clamping force reaches the clamping force corresponding to 0.1g. The second time step is 0.5s-1s, during which the clamping force is maintained at the clamping force corresponding to 0.1g. The third time step is 1s-1.5s. Within the second time step, the clamping force is controlled to reach the clamping force corresponding to 0.3g. The second preset time is 1.5s-2s. Within the second preset time, the clamping force is controlled to maintain the clamping force corresponding to 0.3g. The third time step is 2s-2.5s. Within the third time step, the clamping force is controlled to reach the clamping force corresponding to 0.6g. If the deceleration request is 0.6g, the control of the third time step is executed. If the deceleration request is 0.3g, the control of the third time step is not executed.

[0106] It should be noted that the present invention does not impose any restrictions on the specific values ​​of the preset duration, the first preset deceleration, and the time step; those skilled in the art can set them according to the actual situation.

[0107] See next. Figure 2 The detailed steps of a preferred embodiment of the vehicle EPB system control of the present invention are as follows:

[0108] Step S101: Obtain the vehicle's deceleration request;

[0109] Step S102: Determine the target clamping force based on the obtained deceleration request;

[0110] Step S103: Control the braking mechanism to perform incremental clamping;

[0111] Step S104: During the incremental clamping process of the braking mechanism, obtain the wheel deceleration and wheel slip ratio;

[0112] Step S105: Based on the obtained wheel deceleration and slip ratio, control the braking mechanism to enter dynamic control;

[0113] Step S106: When the braking mechanism is out of dynamic control, obtain the position of the brake piston in the braking mechanism;

[0114] Step S107: Determine whether the vehicle has received a parking brake request;

[0115] Step S108: If the brake piston is in the non-braking position, control the brake piston to move to the braking position;

[0116] Step S109: If the brake piston is not in the initial position, control the brake piston to move to the initial position.

[0117] Step S101 is the same as step S1, step S102 is the same as step S2, and the incremental clamping in step S103 is the same as the incremental clamping control in step S3, which will not be repeated here.

[0118] Further, in step S104, during the incremental clamping process of the braking mechanism, the deceleration and slip ratio of the wheel are acquired. Then, in step S105, based on the acquired wheel deceleration and slip ratio, the braking mechanism is controlled to enter dynamic control. The wheel speed of a single wheel is acquired through a wheel speed sensor, and the wheel deceleration of a single wheel is calculated according to an algorithm. Those skilled in the art can set the algorithm for calculating wheel deceleration according to actual conditions. The wheel slip ratio S is calculated using the following formula:

[0119]

[0120] Where u is the vehicle speed; This refers to the wheel speed; ω is the angular velocity of the wheel; r is the radius of the wheel.

[0121] When using the above formula for calculation, the vehicle speed u can be obtained directly from the vehicle speed sensor, or it can be obtained by acquiring the wheel speeds of all wheels and calculating the vehicle's reference speed based on the wheel speeds of all wheels using an algorithm.

[0122] The above formula is only used to calculate the slip ratio S of a single wheel. , Both and r are parameters for a single wheel. Based on the deceleration and slip ratio of a single wheel, the braking mechanism dynamically controls this wheel.

[0123] Specifically, step S105 includes: if the wheel deceleration is greater than a second preset deceleration or the wheel slip ratio is greater than a first preset slip ratio, then the braking mechanism is controlled to perform a gradual release operation. Specifically, the second preset deceleration is the limit deceleration at which the wheel locks up, and the first preset slip ratio is 8%. If the wheel deceleration is greater than the second preset deceleration, the wheel will lock up. In this case, the braking mechanism is controlled to gradually release to reduce the wheel deceleration and prevent wheel lockup. If the slip ratio is greater than 8%, the wheel may also lock up. In this case, the braking mechanism is controlled to gradually release to reduce the wheel slip ratio and prevent wheel lockup.

[0124] Those skilled in the art will understand that, due to differences in vehicle type, overall structure, or weight, the limit wheel deceleration at which wheel lockup occurs varies for different vehicles. This invention does not impose any restrictions on the specific value of the second preset deceleration, and those skilled in the art can set it according to the actual situation.

[0125] Step S105 further includes: if the wheel slip ratio is less than the second preset slip ratio, then the braking mechanism is controlled to increase the clamping force. Specifically, the second preset slip ratio is 2%. If the slip ratio is less than 2%, it indicates that the braking effect is not good, and the braking mechanism is controlled to increase the clamping force to improve the braking effect.

[0126] Step S105 will continuously switch the braking mechanism between increasing clamping and decreasing release based on the deceleration and slip ratio of the wheel.

[0127] In another preferred embodiment, step S105 further includes: when the braking mechanism is releasing in a decreasing manner, if the slip ratio is less than or equal to a first preset slip ratio and the wheel deceleration is less than or equal to a second preset deceleration, then when the clamping force of the braking mechanism reaches the target clamping force, the clamping force of the braking mechanism is controlled to be maintained at the target clamping force. Specifically, if the slip ratio is less than or equal to 8% and the wheel deceleration is less than or equal to the second preset deceleration, it proves that the wheel will not lock up and can ensure a good braking effect. Therefore, when the clamping force of the braking mechanism reaches the target clamping force, the clamping force of the braking mechanism is controlled to be maintained at the target clamping force.

[0128] In another preferred embodiment, step S105 further includes: if, while maintaining the target clamping force, the slip ratio is greater than 8% or the wheel deceleration is greater than the second preset deceleration, indicating that the wheel may lock up, then the braking mechanism is controlled to perform a decreasing release operation again to avoid wheel lockup.

[0129] In another preferred embodiment, step S105 further includes: when the braking mechanism is performing incremental clamping, if the slip ratio is less than or equal to the first preset slip ratio and the deceleration of the wheel is less than or equal to the second preset deceleration, it proves that the wheel will not lock up and can ensure good braking effect. Therefore, when the clamping force of the braking mechanism reaches the target clamping force, the clamping force of the braking mechanism is controlled to be maintained at the target clamping force.

[0130] In another preferred embodiment, step S105 further includes: if the slip ratio is less than the second preset slip ratio while maintaining the target clamping force, which would result in poor braking effect, then the braking mechanism is controlled to perform incremental clamping again to ensure braking effect.

[0131] Those skilled in the art will understand that although the first preset slip ratio is 8% and the second preset slip ratio is 2% in this invention, this is not limiting. Those skilled in the art can set the specific values ​​of the first preset slip ratio and the second preset slip ratio according to different vehicles, as long as the first preset slip ratio is greater than the second preset slip ratio.

[0132] In one feasible embodiment, the first preset slip ratio is in the range of (8%, 12%), and the second preset slip ratio is in the range of [2%, 8%). In another feasible embodiment, the first preset slip ratio is in the range of [8%, 16%), and the second preset slip ratio is in the range of [2%, 8%). As long as the first preset slip ratio is greater than the second preset slip ratio, it is acceptable.

[0133] Furthermore, in this invention, the decreasing release of the braking mechanism includes: controlling the braking mechanism to release a preset pitch in each preset step. Specifically, the preset step length is 0.5s, and the preset pitch is 0.2 thread pitches. If the braking mechanism uses a decreasing release control, in the first preset step, the drive motor drives the screw to rotate in the opposite direction, causing the sleeve to retract backward by 0.2 thread pitches. This causes the brake piston to retract by 0.2 thread pitches, thereby reducing the clamping force. During the decreasing release process, the wheel deceleration and slip ratio are monitored in real time. If the wheel deceleration and slip ratio meet the requirements, the release stops. If they do not meet the requirements, in the second preset step, the brake piston is driven to retract by 0.2 thread pitches again, releasing a total of 0.4 thread pitches. If the wheel deceleration and slip ratio still do not meet the requirements, in the third preset step, the brake piston is driven to retract by 0.2 thread pitches again, releasing a total of 0.6 thread pitches. This process continues until the wheel deceleration and slip ratio meet the requirements, and the final released pitch does not exceed 1 thread pitch. This is a uniform decreasing release.

[0134] In another preferred embodiment, the braking mechanism's deceleration release is achieved by releasing N times the preset pitch in each preset step, resulting in a progressive deceleration release. For example, if the preset step is 0.5s and the preset pitch is 0.1 pitch, and the braking mechanism uses deceleration release control, in the first preset step, N=1, the drive motor drives the screw to rotate in the opposite direction, causing the sleeve to retract backward by a distance of 1×0.1=0.1 pitch. This, in turn, causes the brake piston to retract by 0.1 pitch, thereby reducing the clamping force. During the deceleration release process, the wheel deceleration and slip ratio are monitored in real time. If the wheel deceleration and slip ratio meet the requirements, the release stops. If the requirements are not met, then in the second preset step (N=2), the brake piston is driven back 2×0.1=0.2 pitches, releasing a total of 0.3 pitches. If the wheel deceleration and slip ratio still do not meet the requirements, then in the third preset step (N=3), the brake piston is driven back 3×0.1=0.3 pitches, releasing a total of 0.6 pitches. This process continues until the wheel deceleration and slip ratio meet the requirements, with the final released pitch not exceeding 1 pitch.

[0135] Those skilled in the art will understand that the preset step size can be 0.5s, 0.1s, or other values, and the preset pitch can be 0.1 pitch, 0.3 pitch, or other values, with a pitch of 2mm-3mm.

[0136] Furthermore, if the braking mechanism exits dynamic control, step S106 is executed to obtain the position of the brake piston within the braking mechanism, and then step S107 is executed to determine whether the vehicle has received a parking brake request.

[0137] When the brake piston is in the initial position, it is in the 0-pitch position. When the brake piston is in the braking position, it is in the 1-pitch position. That is, when the brake piston moves from the initial position to the braking position, it moves forward by 1 pitch.

[0138] Specifically, if the vehicle receives a parking brake request and the brake piston is in the non-braking position, the brake piston is moved to the braking position. For example, if the brake piston is at a position where it has moved forward 0.6 screw pitches, and a parking brake request is received at this time, the brake piston is moved forward another 0.4 screw pitches to bring it to the braking position, thus clamping the vehicle and preventing it from rolling backwards, thereby improving safety. If the brake piston is at a position where it has moved forward 0.6 screw pitches, and no parking brake request is received at this time, indicating that the vehicle is in normal driving condition, the brake piston is moved back 0.6 screw pitches to return it to its initial position, preventing the braking mechanism from clamping the wheels, thus preventing the braking mechanism from affecting the vehicle's speed and avoiding wear on components, extending its service life.

[0139] Those skilled in the art will understand that, although the distance between the initial position and the braking position of the brake piston is 1 pitch in this preferred embodiment, this is not a limitation and other pitch values ​​are also possible. Those skilled in the art can set the pitch according to the specific structure and type of the braking mechanism.

[0140] It should be noted that the wheel control described above is a control method for a single wheel. When the braking mechanism of the present invention performs the decreasing release and increasing clamping operation of the wheel, it controls each wheel in the rear wheel individually. The control method of the present invention can be applied to autonomous vehicles and non-autonomous vehicles. Those skilled in the art can set it according to the actual situation.

[0141] In a second aspect, the present invention also claims a vehicle including a controller configured to perform the control method described in any of the preferred embodiments above.

[0142] It should be noted that this invention does not impose any restrictions on the type or specific structure of the controller. The controller can be a dedicated controller for the EPB system or a main controller for the vehicle. Physically, it can be set up independently or integrated with other modules. Those skilled in the art can set it up according to the actual situation.

[0143] The technical solution of the present invention has been described above with reference to the preferred embodiments shown in the accompanying drawings. However, it will be readily understood by those skilled in the art that the scope of protection of the present invention is obviously not limited to these specific embodiments. Without departing from the principles of the present invention, those skilled in the art can make equivalent changes or substitutions to the relevant technical features, and the technical solutions after such changes or substitutions will all fall within the scope of protection of the present invention.

Claims

1. A control method of a vehicle EPB system, characterized by, The vehicle EPB system comprises a brake mechanism configured to clamp and release wheels of the vehicle; The control method comprises: obtaining a deceleration request of the vehicle; determining a target clamping force according to the obtained deceleration request; controlling the brake mechanism to perform incremental clamping until the clamping force of the brake mechanism reaches the target clamping force; The incremental clamping is to increase the clamping force corresponding to a first preset deceleration by a step each time a preset time interval elapses, wherein the clamping force increased by the nth step is Fn, and Fn is n times of the clamping force F1 increased by the first step.

2. The control method according to claim 1, characterized by, The control method further comprises: obtaining a deceleration of the wheel and a slip ratio of the wheel during the incremental clamping of the brake mechanism; controlling the brake mechanism to enter dynamic control according to the obtained deceleration and slip ratio of the wheel; wherein the dynamic control is switching of the brake mechanism between the incremental clamping and the incremental release, or, the brake mechanism performs the incremental release or the incremental clamping while maintaining the target clamping force.

3. The control method according to claim 2, characterized by, The step of "controlling the brake mechanism to enter dynamic control according to the obtained deceleration and slip ratio of the wheel" specifically comprises: if the deceleration of the wheel is greater than a second preset deceleration or the slip ratio of the wheel is greater than a first preset slip ratio, controlling the brake mechanism to perform the incremental release; and / or if the slip ratio of the wheel is less than a second preset slip ratio, controlling the brake mechanism to perform the incremental clamping; wherein the first preset slip ratio is greater than the second preset slip ratio.

4. The control method according to claim 3, characterized by The step of "controlling the brake mechanism to enter dynamic control according to the obtained deceleration and slip ratio of the wheel" further comprises: if the slip ratio is less than or equal to the first preset slip ratio and the deceleration of the wheel is less than or equal to the second preset deceleration while the brake mechanism is performing the incremental release, controlling the clamping force of the brake mechanism to maintain the target clamping force when the clamping force of the brake mechanism reaches the target clamping force.

5. The control method according to claim 4, characterized by The step of "controlling the brake mechanism to enter dynamic control according to the obtained deceleration and slip ratio of the wheel" further comprises: if the slip ratio is greater than the first preset slip ratio or the deceleration of the wheel is greater than the second preset deceleration while maintaining the target clamping force, controlling the brake mechanism to perform the incremental release again.

6. The control method according to claim 3, characterized by The step of "controlling the brake mechanism to enter dynamic control according to the obtained deceleration and slip ratio of the wheel" further comprises: if the slip ratio is less than or equal to the first preset slip ratio and the deceleration of the wheel is less than or equal to the second preset deceleration while the brake mechanism is performing the incremental clamping, controlling the clamping force of the brake mechanism to maintain the target clamping force when the clamping force of the brake mechanism reaches the target clamping force.

7. The control method according to claim 6, characterized by The step of "controlling the brake mechanism to enter dynamic control according to the obtained deceleration and slip ratio of the wheel" further comprises: If the slip ratio is less than the second preset slip ratio while maintaining the target clamping force, the brake mechanism is controlled to perform incremental clamping work again.

8. The control method according to any one of claims 3 to 7, characterized by, The decremental releasing of the brake mechanism specifically includes: The brake mechanism is controlled to release a preset thread pitch in each preset step.

9. The control method according to any one of claims 3 to 7, characterized by, The control method further includes: In the case that the brake mechanism exits the dynamic control, the position of a brake piston in the brake mechanism is acquired; It is judged whether the vehicle receives a parking brake request; According to the brake piston position of the brake mechanism and the judgment result of whether the vehicle receives the parking brake request, the movement of the brake piston is correspondingly controlled.

10. The control method according to claim 9, characterized by, The specific steps of "according to the brake piston position of the brake mechanism and the judgment result of whether the vehicle receives the parking brake request, the movement of the brake piston is correspondingly controlled" include: If the vehicle receives the parking brake request and the brake piston is located at a non-braking position, the brake piston is controlled to move to a braking position.

11. The control method according to claim 9, characterized by, The specific steps of "according to the brake piston position of the brake mechanism and the judgment result of whether the vehicle receives the parking brake request, the movement of the brake piston is correspondingly controlled" include: If the vehicle does not receive the parking brake request and the brake piston is located at a non-initial position, the brake piston is controlled to move to an initial position.

12. A vehicle comprising a controller, characterized in that The controller is configured to perform the control method of any one of claims 1 to 11.

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