Electromechanical braking system control methods, control devices and vehicles

Abstract

This invention discloses a vehicle braking system, and more particularly, a control method, control device, and vehicle for an electromechanical braking system. The control method includes: determining whether the actual wheel slip ratio exceeds an unstable slip ratio threshold; when the actual wheel slip ratio exceeds the unstable slip ratio threshold, controlling the reduction of the clamping force of the electromechanical braking system on the wheel until the actual wheel slip ratio does not exceed the unstable slip ratio threshold, and recording the current clamping force of the electromechanical braking system on the wheel as the non-slip braking force; the electromechanical braking system continuously brakes the wheel with the non-slip braking force for a preset time; controlling the electromechanical braking system to increase the clamping force on the wheel, and repeatedly checking whether the actual wheel slip ratio exceeds the unstable slip ratio threshold. This invention can more accurately increase the braking force on the wheel while effectively controlling the actual slip ratio of the vehicle within a safe range, thereby improving braking efficiency and safety.

Description

Technical Field

[0001] This invention relates to the configuration of vehicle suspension, and more particularly to an electromechanical braking system control method, control device, and vehicle. Background Technology

[0002] Anti-lock braking systems (ABS) convert the sliding friction between the wheels and the road surface during braking into static friction as much as possible, thereby reducing vehicle slippage and improving driving safety. When the driver brakes and activates the ABS, some electromechanical braking systems typically reduce the clamping force on the wheels, controlling it within a certain range to prevent wheel slippage. This control method has relatively poor precision, affecting the braking effect. Other electromechanical braking systems calculate the slip ratio based on wheel speed and deceleration, controlling the slip ratio within a single slip ratio threshold to prevent wheel slippage. However, in actual driving, wheel slip ratio is affected by various factors, such as the road surface adhesion coefficient. The wheel slip ratio differs depending on whether the wheel is traveling on a high-adhesion surface like asphalt or on a low-adhesion surface like ice or snow. A single slip ratio threshold cannot adequately reduce the likelihood of wheel lock-up. Furthermore, if only a single slip ratio threshold is set for judgment before feedback control of the clamping force, it means that the clamping force is only reduced when the wheel is already in an unstable state. At this point, the reduction in clamping force is relatively late, resulting in a larger change in clamping force. This means that the change in wheel slip ratio always lags behind the change in wheel braking force; that is, an increase in wheel braking force does not immediately lead to an increase in wheel slip ratio, nor does a decrease in wheel braking force immediately lead to a decrease in wheel slip ratio. Therefore, it is impossible to control the actual wheel slip ratio within a good range, resulting in significant fluctuations in the actual wheel slip ratio and relatively poor braking performance. Therefore, a precise and reliable electromechanical braking system control method is urgently needed. Summary of the Invention

[0003] The purpose of this invention is to provide an electromechanical braking system control method, control device, and vehicle to solve one or more technical problems existing in the prior art, and at least provide a beneficial option or create conditions.

[0004] According to a first aspect of the present invention, a control method for an electromechanical braking system includes:

[0005] Obtain the vehicle's wheel speed, wheel deceleration, road surface adhesion coefficient, and driving speed;

[0006] Calculate the actual wheel slip ratio and the unstable slip ratio threshold based on the wheel speed, the wheel deceleration, the road surface adhesion coefficient, and the driving speed;

[0007] Determine whether the actual slip ratio of the wheel exceeds the unstable slip ratio threshold;

[0008] When the actual slip ratio of the wheel exceeds the unstable slip ratio threshold, the clamping force of the electromechanical braking system on the wheel is reduced until the actual slip ratio of the wheel does not exceed the unstable slip ratio threshold, and the current clamping force of the electromechanical braking system on the wheel is recorded as the non-slip braking force.

[0009] The electromechanical braking system continuously brakes the wheels with the non-slip braking force and a preset time.

[0010] The electromechanical braking system is controlled to increase the clamping force on the wheel, and the actual wheel slip rate is repeatedly checked to see if it exceeds the unstable slip rate threshold.

[0011] This technical solution has at least the following beneficial effects: When braking a vehicle, the vehicle's wheel speed, wheel deceleration, road adhesion coefficient, and driving speed are acquired. Since wheel speed, wheel deceleration, and driving speed affect the wheel slip ratio in real time, the actual wheel slip ratio and unstable slip ratio threshold are calculated based on the current wheel speed, wheel deceleration, and driving speed. When the actual wheel slip ratio exceeds the unstable slip ratio threshold, the clamping force of the electromechanical braking system on the wheel needs to be reduced until the actual wheel slip ratio does not exceed the unstable slip ratio threshold, which helps ensure driving safety. At this time, the current clamping force of the electromechanical braking system on the wheel is maintained for a set braking time, allowing the wheel to decelerate in a safe state. When the mechanical braking system applies excessively reduced clamping force to the wheels, and the wheel speed is reduced while maintaining wheel clamping, the actual wheel slip ratio and the unstable slip ratio threshold also change. To improve braking efficiency, the clamping force on the wheels is increased to enhance braking effect. To ensure driving safety, the above steps of judging whether the actual wheel slip ratio exceeds the unstable slip ratio threshold are repeated to ensure a rapid response when the actual wheel slip ratio exceeds the unstable slip ratio threshold. By continuously comparing the vehicle's driving state during braking, the clamping force on the wheels can be adjusted in a timely manner, more accurately increasing the braking force on the wheels while effectively controlling the vehicle's actual slip ratio within a safe range, thus improving braking efficiency and safety.

[0012] According to some embodiments of the present invention, after controlling the reduction of the clamping force of the electromechanical braking system on the wheel until the actual slip ratio of the wheel does not exceed the unstable slip ratio threshold, the method further includes:

[0013] Determine whether the wheel deceleration exceeds a preset wheel deceleration threshold;

[0014] When the wheel deceleration exceeds the preset wheel deceleration threshold, the current clamping force of the electromechanical braking system on the wheel is recorded as the non-slip braking force.

[0015] According to some embodiments of the present invention, the electromechanical braking system control method further includes:

[0016] When the wheel deceleration does not exceed the preset wheel deceleration threshold, the electromechanical braking system is activated to continuously brake the wheel with the non-slip braking force and the preset time.

[0017] According to some embodiments of the present invention, the electromechanical braking system control method further includes:

[0018] When the actual slip ratio of the wheel does not exceed the unstable slip ratio threshold, the electromechanical braking system is controlled to increase the clamping force on the wheel.

[0019] According to some embodiments of the present invention, controlling the electromechanical braking system to increase the clamping force on the wheel brakes includes:

[0020] The reduction in wheel clamping force by the electromechanical braking system is denoted as the basic clamping force reduction. , The wheel clamping force at the initial moment, The road surface adhesion coefficient, and These are the preset reference constants;

[0021] The non-slip braking force is increased by controlling the increase and recorded as the adjusted clamping force. The increase in the non-slip braking force is not greater than the decrease in the basic clamping force.

[0022] The electromechanical braking system is controlled to brake the wheels with the adjusted clamping force.

[0023] According to some embodiments of the present invention, the electromechanical braking system control method further includes:

[0024] The electromechanical braking system is repeatedly controlled to increase the clamping force on the wheels to obtain multiple adjusted clamping forces, wherein the current adjusted clamping force is greater than the previous adjusted clamping force.

[0025] According to some embodiments of the present invention, the electromechanical braking system control method further includes:

[0026] When the increase in the non-slip braking force reaches a preset increase threshold, the control reduces the increase in the non-slip braking force in the clamping force of the electromechanical braking system that increases the braking force on the wheels.

[0027] According to some embodiments of the present invention, the calculation of the actual wheel slip ratio and the unstable slip ratio threshold by the wheel speed, the wheel deceleration, and the travel speed includes:

[0028] The formula for calculating the actual slip ratio of the wheel is: ,in, This represents the actual slip ratio of the wheel. The driving speed is... Let a be the wheel speed, and a and b be preset reference constants.

[0029] According to some embodiments of the present invention, the calculation of the actual wheel slip ratio and the unstable slip ratio threshold by the wheel speed, the wheel deceleration, and the travel speed includes:

[0030] A preset instability coefficient is determined based on the road surface adhesion coefficient;

[0031] The unstable slip ratio threshold is calculated using the following formula: ,in, The unstable slip rate threshold, To preset the slip ratio threshold, To preset the instability coefficient, The wheel decelerates.

[0032] According to some embodiments of the present invention, after controlling the electromechanical braking system to increase the clamping force on the wheel brakes, it further includes...

[0033] Determine whether the driving speed has reached the target speed;

[0034] When the driving speed does not reach the target vehicle speed, the process of repeatedly checking whether the actual wheel slip rate exceeds the unstable slip rate threshold is repeated.

[0035] According to some embodiments of the present invention, the electromechanical braking system control method further includes:

[0036] When the driving speed reaches the target vehicle speed, the electromechanical braking system is controlled to stop braking the wheels.

[0037] According to a second aspect of the present invention, a vehicle control device includes a memory, a processor, and a program stored in the memory and executable on the processor. When the program is executed by the processor, it implements the electromechanical braking system control method of the above embodiment.

[0038] The technical solution has at least the following beneficial effects: the above-mentioned electromechanical braking system control method can be implemented as a computer program and tangibly contained in the vehicle control device. When the processor uses this computer-readable storage medium to perform the electromechanical braking system control method, by continuously comparing the vehicle's driving state during braking, it can promptly provide feedback to adjust the clamping force on the wheels, more accurately improve the braking force on the wheels, and effectively control the actual slip ratio of the vehicle within a safe range, thereby improving braking efficiency and safety.

[0039] A vehicle according to a third aspect of the present invention includes the vehicle control device described above.

[0040] This technical solution has at least the following beneficial effects: When the vehicle is braked using this electromechanical braking system control method, by continuously comparing the vehicle's driving state during braking, the clamping force on the wheels can be adjusted in a timely manner, thereby more accurately improving the braking force on the wheels while effectively controlling the actual slip ratio of the vehicle within a safe range, thus improving braking efficiency and safety.

[0041] According to a fourth aspect of the present invention, a computer-readable storage medium stores computer-executable instructions for causing a computer to perform the above-described electromechanical braking system control method.

[0042] The technical solution has at least the following beneficial effects: the above-mentioned electromechanical braking system control method can be implemented as a computer program and tangibly contained in a computer-readable storage medium. When the processor uses this computer-readable storage medium to perform the electromechanical braking system control method, by continuously comparing the vehicle's driving state during braking, it can promptly adjust the clamping force on the wheels, more accurately improve the braking force on the wheels, and effectively control the actual slip ratio of the vehicle within a safe range, thereby improving braking efficiency and safety.

[0043] A computer program product according to a fifth aspect of the present invention includes a computer-readable storage medium capable of executing the above description.

[0044] The technical solution has at least the following beneficial effects: The computer program product contains the above-mentioned electromechanical braking system control method. By using this computer program product to control the anti-lock braking of the electromechanical braking system, and by continuously comparing the vehicle's driving state during braking, the clamping force on the wheels can be adjusted in a timely manner, thereby more accurately improving the braking force on the wheels while effectively controlling the actual slip ratio of the vehicle within a safe range, thus improving braking efficiency and safety.

[0045] Additional aspects and advantages of the invention will be set forth in part in the description which follows, and in part will be derived from the description.

[0046] It will become apparent, or will be understood through the practice of the present invention. Attached Figure Description

[0047] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly explained below. Obviously, the described drawings are only a part of the embodiments of the present invention, and not all of them. Those skilled in the art can obtain other design schemes and drawings based on these drawings without creative effort.

[0048] Figure 1 This is a flowchart of the electromechanical braking system control method of the present invention.

[0049] Figure 2 This is a flowchart of step S400 of the present invention.

[0050] Figure 3 This is a flowchart of step S600 of the present invention. Detailed Implementation

[0051] Embodiments of the present invention are described in detail below. Examples of these embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and should not be construed as limiting the present invention.

[0052] In the description of this invention, it should be understood that the orientation descriptions, such as up, down, front, back, left, right, etc., are based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limiting this invention.

[0053] In the description of this invention, "several" means one or more, "more than" means two or more, "greater than," "less than," and "exceeding" are understood to exclude the stated number, while "above," "below," and "within" are understood to include the stated number. The use of "first" and "second" in the description is merely for distinguishing technical features and should not be construed as indicating or implying relative importance, or implicitly indicating the number of indicated technical features, or implicitly indicating the order of the indicated technical features.

[0054] In the description of this invention, unless otherwise explicitly defined, terms such as "set up," "install," and "connect" should be interpreted broadly, and those skilled in the art can reasonably determine the specific meaning of the above terms in this invention in conjunction with the specific content of the technical solution.

[0055] Reference Figure 1According to a first aspect of the present invention, an electromechanical braking system control method includes, but is not limited to, the following steps:

[0056] Step S100: Obtain the vehicle's wheel speed, wheel deceleration, road surface adhesion coefficient, and driving speed. While the vehicle is in motion, the system maintains the acquisition of vehicle information to update the vehicle's state. Since the vehicle will have different slip ratios at different driving speeds and wheel rotation speeds, it is necessary to obtain the vehicle's wheel speed, wheel deceleration, road surface adhesion coefficient, and driving speed information.

[0057] Step S200: Calculate the actual slip ratio and unstable slip ratio threshold of the wheel based on the wheel speed, wheel deceleration, road surface adhesion coefficient, and driving speed. By using the acquired wheel speed, wheel deceleration, and driving speed information to calculate the actual slip ratio and unstable slip ratio threshold of the wheel, the driving stability of the current wheel can be assessed in a timely manner.

[0058] Step S300: Determine whether the actual wheel slip ratio exceeds the unstable slip ratio threshold. After braking the vehicle, the current actual wheel slip ratio can be compared with the unstable slip ratio threshold, which determines whether the vehicle will slip at this time, to determine whether there is a risk of slippage. When the actual wheel slip ratio exceeds the unstable slip ratio threshold, the vehicle is at risk of slippage; when the actual wheel slip ratio does not exceed the unstable slip ratio threshold, the vehicle is not at risk of slippage.

[0059] When the actual wheel slip ratio exceeds the unstable slip ratio threshold, the process proceeds to step S400, where the clamping force of the electromechanical braking system on the wheel is reduced until the actual wheel slip ratio does not exceed the unstable slip ratio threshold. The current clamping force of the electromechanical braking system on the wheel is then recorded as the non-slip braking force. When the actual wheel slip ratio exceeds the unstable slip ratio threshold, vehicle braking intervention is required. By reducing the clamping force of the electromechanical braking system on the wheel, the braking force on the wheel is weakened. After reducing the actual wheel slip ratio to below the unstable slip ratio threshold, the risk of vehicle slippage can be effectively reduced, which helps ensure driving safety.

[0060] In step S500, the electromechanical braking system continuously brakes the wheels with a non-slip braking force for a preset time. After maintaining braking on the wheels for a period of time while ensuring the clamping force does not cause wheel slippage, the wheel speed, wheel deceleration, and travel speed are reduced. At this point, the unstable slip rate threshold also changes, making wheel slippage less likely.

[0061] In step S600, the electromechanical braking system is controlled to increase the clamping force on the wheels, and step S300 is repeated to check whether the actual wheel slip ratio exceeds the unstable slip ratio threshold. At this time, the clamping force on the wheels is increased based on the non-slip braking force to further enhance the braking effect on the wheels. The actual wheel slip ratio after increasing the braking force needs to be judged repeatedly to improve the braking efficiency of the wheels while ensuring driving safety.

[0062] As described above, when braking a vehicle, the vehicle's wheel speed, wheel deceleration, road adhesion coefficient, and travel speed are acquired. Since wheel speed, wheel deceleration, and travel speed affect the wheel slip ratio in real time, the actual wheel slip ratio and unstable slip ratio threshold are calculated based on the current wheel speed, wheel deceleration, and travel speed. When the actual wheel slip ratio exceeds the unstable slip ratio threshold, the clamping force of the electromechanical braking system on the wheel needs to be reduced until the actual wheel slip ratio does not exceed the unstable slip ratio threshold, which helps ensure driving safety. At this time, the current clamping force of the electromechanical braking system is used to maintain the braking for a set time, allowing the wheel to decelerate in a safe state. This is because reducing the clamping force of the electromechanical braking system... There is a possibility of excessive reduction in the clamping force on the wheels, and the wheel speed is reduced while maintaining wheel clamping and braking. At this time, the actual wheel slip ratio and the unstable slip ratio threshold also change. In order to improve braking efficiency, the clamping force on the wheels is increased to improve the braking effect. To ensure driving safety, the above steps of judging whether the actual wheel slip ratio exceeds the unstable slip ratio threshold are repeated to ensure a rapid response when the actual wheel slip ratio exceeds the unstable slip ratio threshold. In this way, by continuously comparing the driving state of the vehicle during braking, the clamping force on the wheels can be adjusted in a timely manner, which can more accurately improve the braking force on the wheels while effectively controlling the actual slip ratio of the vehicle within a safe range, thereby improving braking efficiency and safety.

[0063] In step S400, in order to better ensure stable vehicle movement after the braking force is reduced, such as... Figure 2As shown, in this embodiment, in step S410, the clamping force of the electromechanical braking system on the wheel is reduced until the actual wheel slip ratio does not exceed the unstable slip ratio threshold. Then, in step S420, it is determined whether the wheel deceleration exceeds a preset wheel deceleration threshold. When the wheel deceleration exceeds the preset wheel deceleration threshold, step S430 is performed to record the current clamping force of the electromechanical braking system on the wheel as the non-slip braking force. Thus, when determining whether the wheel is moving stably, in addition to judging the slip ratio, the wheel deceleration requirement must also be met. When the actual wheel slip ratio does not exceed the unstable threshold and the wheel deceleration exceeds the preset wheel deceleration threshold, the wheel is determined to be in a stable state, and then the subsequent braking action of maintaining the current clamping force on the wheel is performed.

[0064] In step S420, when the wheel deceleration does not exceed a preset wheel deceleration threshold, the process proceeds to step S500, where the electromechanical braking system continuously brakes the wheel with a non-slip braking force for a preset time. When the clamping force does not cause wheel slippage, as the wheel speed decreases, the corresponding wheel deceleration threshold also decreases, ensuring that the wheel deceleration generated by the current clamping force exceeds the wheel deceleration threshold, thus guaranteeing the stability of the wheel's movement.

[0065] In step S300, when the actual wheel slip ratio does not exceed the unstable slip ratio threshold, there is no risk of slippage during vehicle braking. At this point, the process can proceed to step S600 to control the electromechanical braking system to increase the clamping force on the wheels. In practical applications, when the actual wheel slip ratio does not exceed the unstable slip ratio threshold, the process can also proceed to step S420 to determine whether the wheel deceleration exceeds a preset wheel deceleration threshold. If the wheel deceleration exceeds the preset wheel deceleration threshold, the process then proceeds to step S600 to control the electromechanical braking system to increase the clamping force on the wheels. When the actual wheel slip ratio does not exceed the unstable slip ratio threshold, the clamping force on the wheels can be further increased, thereby enhancing wheel braking.

[0066] In step S600, the electromechanical braking system is controlled to increase the clamping force on the wheels, such as... Figure 3 As shown, including but not limited to the following steps:

[0067] Step S610: Record the reduction in the wheel clamping force of the electromechanical braking system as the reduction in basic clamping force. , The wheel clamping force at the initial moment, The road surface adhesion coefficient, and These are preset reference constants. The decrease in basic clamping force is related to the wheel clamping force at the moment the instability condition is met, and the calculation formula is as follows: . The reduction in basic clamping force Here, c is the wheel clamping force at the beginning, c is a preset reference constant, which can be between 0.1 and 0.3, preferably 0.2; d is a preset reference constant, which can be between 0.05 and 0.2, preferably 0.1. The road surface adhesion coefficient (GFC) can range from 0.01 to 1. For example, the GFC is approximately 0.8 on asphalt pavement and approximately 0.1 on icy or snowy pavement. The clamping force value is obtained when unstable conditions are met. This clamping force value can reflect the current road surface condition to some extent. The reduction in the base clamping force is related to this clamping force value. When the GFC is higher, the wheel speed change is smaller compared to low-adhesion pavement, thus requiring a larger reduction in the base clamping force. Conversely, when the GFC is lower, the wheel speed change is larger compared to high-adhesion pavement, thus requiring a smaller reduction in the base clamping force.

[0068] Step S620: Control the increase of the non-slip braking force and record it as the adjusted clamping force. The increase in the non-slip braking force should not exceed the decrease in the basic clamping force. Since the actual wheel slip ratio exceeds the unstable slip ratio threshold when the wheel clamping force is reduced, that is, the wheel clamping force is too large at this time, the total decrease in clamping force when the wheel clamping force is reduced to the non-slip braking force is recorded as the basic clamping force reduction. When it is necessary to increase the wheel clamping force, the clamping force is increased by no more than the basic force reduction on the basis of the non-slip braking force. This can better control the increase in clamping force and avoid wheel slippage caused by excessive clamping force.

[0069] In step S630, the electromechanical braking system is controlled to adjust the clamping force on the wheels. That is, the clamping force on the wheels is further increased based on the non-slip braking force in an attempt to enhance the braking effect on the wheels and improve braking efficiency.

[0070] During step S600, there might be a situation where a single increase in clamping force causes the actual wheel slip ratio to exceed the unstable slip ratio threshold, or where the actual wheel slip ratio has not yet exceeded the unstable slip ratio threshold after a single increase in clamping force. In such cases, step S600 will be re-entered to increase the clamping force again. This process will be repeated multiple times, controlling the electromechanical braking system to increase the clamping force on the wheel to obtain multiple adjusted clamping forces, each adjusted clamping force being greater than the previous one. This gradual increase in clamping force, forming a step-like progression, helps avoid the problem of a sudden increase in slip ratio due to excessively rapid increases in clamping force, thus improving braking stability.

[0071] Furthermore, during multiple executions of step S600, when the increase in non-slip braking force reaches a preset increase threshold, the control system reduces the increase in non-slip braking force within the clamping force applied to the wheels. In this braking method, the increase in wheel clamping force is relatively large in the initial stages, allowing for a rapid increase in braking force. However, in later stages, as the wheel clamping force gradually increases, wheel slippage becomes more likely. Therefore, reducing the increase in wheel clamping force improves the precision of clamping force control. For example, the clamping force is increased multiple times based on the non-slip braking force until it reaches 75% of the reduction in the basic clamping force. During this initial stage, the increase in clamping force is relatively large each time, for example, 0.1 to 0.3 of the reduction in the basic clamping force each time, preferably 0.2 of the reduction in the basic clamping force. When the clamping force continues to increase, from 75% to 100% of the reduction in the basic clamping force, the increase in clamping force each time can be 0.1 to 0.3 of the reduction in the basic clamping force, but the increase in clamping force each time is smaller than the increase in clamping force at the initial step, preferably 0.15 of the reduction in the basic clamping force. This improves the control of the step increase in clamping force, thereby further improving braking stability.

[0072] In step S200, the formula for calculating the actual wheel slip ratio is: ,in, This represents the actual slip ratio of the wheel. For driving speed, Here, 'a' represents the wheel speed, and 'b' is a preset reference constant. The value of 'a' is between 0 and 10, preferably 6. The value of 'b' is between 1 and 1.2, preferably 1.1. In this calculation formula, when the driving speed is relatively low, the slip ratio is reduced, allowing for a larger slip ratio, thus enhancing braking force and increasing wheel deceleration. When the driving speed is high, the slip ratio is amplified, making changes in slip ratio more sensitive. Therefore, it is necessary to gradually reduce the braking force to improve the braking stability of the vehicle at high speeds.

[0073] In step S200, a preset instability coefficient is first determined based on the road surface adhesion coefficient, and then the unstable slip ratio threshold is calculated. The formula for calculating the unstable slip ratio threshold is as follows: ,in, The unstable slip rate threshold, To preset the slip ratio threshold, To preset the instability coefficient, To slow down the wheels, The value of this threshold is generally between 0.005 and 0.02. The unstable slip ratio threshold takes into account the change in wheel deceleration, which reflects how quickly the wheel speed changes. If the wheel deceleration is too large, it means that the wheel speed changes very quickly, and the wheel can easily change from a stable state to an unstable state rapidly. When the wheel deceleration is large, since the wheel deceleration is negative, the unstable slip ratio threshold calculated in real time according to the above formula is relatively smaller, which allows the wheel to identify the possible unstable state in advance, reduce the clamping force in advance, and improve the braking effect. The rate of change of wheel speed is related to the preset instability coefficient, and the road surface adhesion coefficient affects the preset instability coefficient. On low-adhesion surfaces such as icy and snowy roads, the adhesion between the tire and the ground is very small, so the wheel is more likely to lock up. A small braking force will produce a large slip ratio, requiring the unstable slip ratio threshold to be set lower and the clamping force to be reduced in advance. Therefore, a larger preset value for the instability coefficient results in a lower unstable slip ratio threshold calculated by the formula, which is more conducive to control on low-adhesion pavements and effectively solves the problem that a single slip ratio threshold cannot be adjusted according to different pavement environments.

[0074] The preset instability coefficient is related to the road surface adhesion coefficient. When the road surface adhesion coefficient is less than 0.2, the preset instability coefficient is 0.02; when the road surface adhesion coefficient is between 0.2 and 0.8, the preset instability coefficient is 0.01; when the road surface adhesion coefficient is greater than 0.8, the preset instability coefficient is 0.005.

[0075] Assuming a road surface with a coefficient of friction of approximately 0.1 on icy or snowy roads, a clamping force of 10 kN would provide optimal braking performance. However, in real-world vehicles, changes in wheel slip ratio always lag behind changes in wheel braking force. An increase in braking force does not immediately lead to an increase in wheel slip ratio, nor does a decrease in braking force immediately lead to a decrease in wheel slip ratio. Therefore, a wheel may not have slip ratio at a clamping force of 10 kN, but it might increase significantly at 11 kN. However, on low-friction surfaces, wheel speed changes rapidly (i.e., wheel deceleration is high), making wheel lockup easy. Ignoring the effect of wheel deceleration and only reducing the clamping force at 11 kN would make wheel lockup even more likely. By calculating the unstable slip ratio threshold using wheel deceleration and the instability coefficient, and lowering this threshold on low-friction surfaces, the clamping force can be reduced earlier, at 10.5 kN, effectively reducing the possibility of wheel lockup and improving braking performance.

[0076] In step S600, after controlling the electromechanical braking system to increase the clamping force on the wheels, the process proceeds to step S700 to determine whether the driving speed has reached the target speed. The target speed is the speed that the driver needs to achieve by braking, for example, a driving speed of 0. If the driving speed has not reached the target speed, the process of determining whether the actual wheel slip ratio exceeds the unstable slip ratio threshold is repeated. Only when the driving speed has not reached the target speed does the clamping force determination process need to be repeated. When the driving speed reaches the target speed, the process proceeds to step S800, where the electromechanical braking system stops braking the wheels. At this point, braking of the vehicle is complete, and no further braking operation is required.

[0077] In summary, several more embodiments of this electromechanical braking system control method under different conditions are provided here:

[0078] In Example 1, when the driver is traveling at a certain speed and depresses the brake pedal, if the actual wheel slip ratio exceeds the unstable slip ratio threshold, the wheel enters an unstable state. Based on the current clamping force, the amount of clamping force reduction is determined, and the electromechanical braking system is initiated to release the brakes. After release, a clamping force holding phase begins, lasting for a set time, e.g., 0.1 seconds. Once the wheel is in a stable state, it enters the clamping process. The basic clamping force reduction is determined based on the sum of the clamping force reductions from the previous release phase, and clamping is performed sequentially according to a stepped, increasing clamping force gradient. When the wheel again meets the unstable condition, it enters the release state again, and the above process repeats. This cycle of release, holding, and clamping continues until the vehicle comes to a complete stop.

[0079] In Example 2, when the driver is driving at a certain speed and depresses the brake pedal, if the actual wheel slip ratio exceeds the unstable slip ratio threshold, the wheel enters an unstable state. Based on the current clamping force, the amount of clamping force reduction is determined, and the electromechanical braking system is initiated to release the brakes. After release, a clamping force holding phase begins, lasting for a set time, e.g., 0.1 seconds. If the wheel is still in an unstable state, a second release process begins, and the clamping force reduction is determined again based on the current clamping force. After the second release, a clamping force holding phase begins, lasting for 0.1 seconds. If the wheel is now in a stable state, it enters a clamping process. The basic clamping force reduction is determined based on the sum of the clamping force reductions from the previous release process, and clamping is performed sequentially according to a stepped increasing clamping force gradient. When the wheel again meets the unstable condition, it enters the release state again, and the above process repeats. This cycle of release, holding, and clamping continues until the vehicle comes to a complete stop.

[0080] In Example 3, when the driver is driving at a certain speed and depresses the brake pedal, if the actual wheel slip ratio exceeds the unstable slip ratio threshold, the wheel enters an unstable state. Based on the current clamping force, the amount of clamping force reduction is determined, and the electromechanical braking system is initiated to release the brakes. After release, a clamping force holding phase begins, lasting for a set time, e.g., 0.1 seconds. If the wheel then stabilizes, it enters the clamping process. The basic clamping force reduction is determined based on the sum of the clamping force reductions from the previous release phase, and clamping is performed sequentially according to a stepped, increasing clamping force gradient. If the wheel remains stable after the clamping force increases, the wheel is clamped with a larger clamping force gradient until the wheel meets the instability condition. The wheel then enters the release state again, and the above process repeats. This cycle of release, holding, and clamping continues until the vehicle comes to a complete stop.

[0081] According to a second aspect of the present invention, a vehicle control device includes a memory, a processor, and a program stored in the memory and executable on the processor. When the program is executed by the processor, it implements the electromechanical braking system control method of the above embodiments.

[0082] The aforementioned electromechanical braking system control method can be implemented as a computer program and tangibly incorporated into the vehicle control device. When the processor uses this computer-readable storage medium to perform the electromechanical braking system control method, by continuously comparing the vehicle's driving state during braking, it can promptly provide feedback and adjust the clamping force on the wheels, more accurately improve the braking force on the wheels, and effectively control the actual slip ratio of the vehicle within a safe range, thereby improving braking efficiency and safety.

[0083] Taking the example of a processor and memory in a vehicle control device being connected via a bus, the memory, as a non-transitory computer-readable storage medium, can be used to store non-transitory software programs and non-transitory computer-executable programs. Furthermore, the memory may include high-speed random access memory, and may also include non-transitory memory, such as at least one disk storage device, flash memory device, or other non-transitory solid-state storage device. In some embodiments, the memory may optionally include memory remotely located relative to the control processor, and these remote memories can be connected to the control device via a network.

[0084] A vehicle according to a third aspect of the present invention includes the vehicle control device described above. The vehicle can be a private car, such as a sedan, SUV, MPV, or pickup truck. The vehicle can also be a commercial vehicle, such as a van, bus, small truck, or large trailer. The vehicle needs to have an electric motor capable of outputting power or storing mechanical energy as a generator. When the vehicle is a new energy vehicle, it can be a hybrid vehicle or a pure electric vehicle.

[0085] When a vehicle is braked using this electromechanical braking system control method, the vehicle's driving state during braking is continuously compared, and the clamping force on the wheels can be adjusted in a timely manner. This more accurately increases the braking force on the wheels while effectively controlling the vehicle's actual slip ratio within a safe range, thereby improving braking efficiency and safety.

[0086] According to a fourth aspect of the present invention, a computer-readable storage medium stores computer-executable instructions for causing a computer to perform the above-described electromechanical braking system control method.

[0087] The aforementioned electromechanical braking system control method can be implemented as a computer program and tangibly contained in a computer-readable storage medium. When the processor uses this computer-readable storage medium to perform the electromechanical braking system control method, by continuously comparing the vehicle's driving state during braking, it can promptly provide feedback and adjust the clamping force on the wheels, more accurately improve the braking force on the wheels, and effectively control the actual slip ratio of the vehicle within a safe range, thereby improving braking efficiency and safety.

[0088] It is worth noting that, since the computer-readable storage medium of the present invention can execute the anti-lock control method of any of the above embodiments, the specific implementation and technical effects of the computer-readable storage medium of the present invention can be referred to the specific implementation and technical effects of the anti-lock control method of any of the above embodiments.

[0089] A computer program product according to a fifth aspect of the present invention includes a computer-readable storage medium capable of executing the above description.

[0090] It is worth noting that, since the computer program product of this embodiment can execute the electromechanical braking system control method of any of the above embodiments, the specific implementation method and technical effect of the computer program product of this embodiment can be referred to the specific implementation method and technical effect of the electromechanical braking system control method of any of the above embodiments.

[0091] The computer program product contains the aforementioned electromechanical braking system control method. Utilizing this computer program product for anti-lock braking control of the electromechanical braking system, by continuously comparing the vehicle's driving state during braking, it can promptly adjust the clamping force on the wheels, more accurately improving the braking force while effectively controlling the vehicle's actual slip ratio within a safe range, thus improving braking efficiency and safety. Those skilled in the art will understand that all or some steps and systems in the methods disclosed above can be implemented as software, firmware, hardware, and suitable combinations thereof. Some or all physical components can be implemented as software executed by a processor, such as a central processing unit, digital signal processor, or microprocessor, or as hardware, or as integrated circuits, such as application-specific integrated circuits. Such software can be distributed on a computer-readable medium, which can include computer storage media (or non-transitory media) and communication media (or transient media). As is known to those skilled in the art, the term computer storage media includes volatile and non-volatile, removable and non-removable media implemented in any method or technology for storing information (such as computer-readable instructions, data structures, program modules, or other data). Computer storage media include, but are not limited to, RAM, ROM, EEPROM, flash memory or other memory technologies, CD-ROM, digital versatile disc (DVD) or other optical disc storage, magnetic cartridges, magnetic tape, disk storage or other magnetic storage devices, or any other medium that can be used to store desired information and can be accessed by a computer. Furthermore, it is well known to those skilled in the art that communication media typically include computer-readable instructions, data structures, program modules, or other data in modulated data signals such as carrier waves or other transmission mechanisms, and may include any information delivery medium.

[0092] The preferred embodiments of the present invention have been described in detail above, but the present invention is not limited to the embodiments described. Those skilled in the art can make various equivalent modifications or substitutions without departing from the spirit of the present invention, and these equivalent modifications or substitutions are all included within the scope defined by the claims of this application.

Claims

1. A control method for an electromechanical braking system, characterized in that: include: Obtain the vehicle's wheel speed, wheel deceleration, road surface adhesion coefficient, and driving speed; Calculate the actual wheel slip ratio and the unstable slip ratio threshold based on the wheel speed, the wheel deceleration, the road surface adhesion coefficient, and the driving speed; Determine whether the actual slip ratio of the wheel exceeds the unstable slip ratio threshold; When the actual slip ratio of the wheel exceeds the unstable slip ratio threshold, the clamping force of the electromechanical braking system on the wheel is reduced until the actual slip ratio of the wheel does not exceed the unstable slip ratio threshold, and the current clamping force of the electromechanical braking system on the wheel is recorded as the non-slip braking force. The electromechanical braking system continuously brakes the wheels with the non-slip braking force and a preset time. The electromechanical braking system is controlled to increase the clamping force on the wheel brakes, and the actual wheel slip rate is repeatedly checked to see if it exceeds the unstable slip rate threshold. The calculation of the actual wheel slip ratio and the unstable slip ratio threshold by the wheel speed, the wheel deceleration, and the travel speed includes: The formula for calculating the actual slip ratio of the wheel is: ,in, This represents the actual slip ratio of the wheel. The driving speed is... The wheel speed is given by a, and both a and b are preset reference constants. A preset instability coefficient is determined based on the road surface adhesion coefficient; The unstable slip ratio threshold is calculated using the following formula: ,in, The unstable slip rate threshold, To preset the slip ratio threshold, To preset the instability coefficient, The wheel decelerates.

2. The electromechanical braking system control method according to claim 1, characterized in that: The control of reducing the clamping force of the electromechanical braking system on the wheel until the actual slip ratio of the wheel does not exceed the unstable slip ratio threshold further includes: Determine whether the wheel deceleration exceeds a preset wheel deceleration threshold; When the wheel deceleration exceeds the preset wheel deceleration threshold, the current clamping force of the electromechanical braking system on the wheel is recorded as the non-slip braking force.

3. The electromechanical braking system control method according to claim 2, characterized in that: The electromechanical braking system control method further includes: When the wheel deceleration does not exceed the preset wheel deceleration threshold, the electromechanical braking system is activated to continuously brake the wheel with the non-slip braking force and the preset time.

4. The electromechanical braking system control method according to claim 1, characterized in that: The electromechanical braking system control method further includes: When the actual slip ratio of the wheel does not exceed the unstable slip ratio threshold, the electromechanical braking system is controlled to increase the clamping force on the wheel.

5. The electromechanical braking system control method according to claim 4, characterized in that: The control of the electromechanical braking system to increase the clamping force on the wheels includes: The reduction in wheel clamping force by the electromechanical braking system is denoted as the basic clamping force reduction. , The wheel clamping force at the initial moment. The road surface adhesion coefficient, and These are the preset reference constants; The non-slip braking force is increased by controlling the increase and recorded as the adjusted clamping force. The increase in the non-slip braking force is not greater than the decrease in the basic clamping force. The electromechanical braking system is controlled to brake the wheels with the adjusted clamping force.

6. The electromechanical braking system control method according to claim 5, characterized in that: The electromechanical braking system control method further includes: The electromechanical braking system is repeatedly controlled to increase the clamping force on the wheels to obtain multiple adjusted clamping forces, wherein the current adjusted clamping force is greater than the previous adjusted clamping force.

7. The electromechanical braking system control method according to claim 6, characterized in that: The electromechanical braking system control method further includes: When the increase in the non-slip braking force reaches a preset increase threshold, the control reduces the increase in the non-slip braking force in the clamping force of the electromechanical braking system that increases the braking force on the wheels.

8. The electromechanical braking system control method according to claim 1, characterized in that: After controlling the electromechanical braking system to increase the clamping force on the wheels, the method further includes: Determine whether the driving speed has reached the target speed; When the driving speed does not reach the target vehicle speed, the process of repeatedly checking whether the actual wheel slip rate exceeds the unstable slip rate threshold is repeated.

9. The electromechanical braking system control method according to claim 8, characterized in that: The electromechanical braking system control method further includes: When the driving speed reaches the target vehicle speed, the electromechanical braking system is controlled to stop braking the wheels.

10. A vehicle control device, characterized in that: It includes a memory, a processor, and a program stored in the memory and executable on the processor, wherein the program, when executed by the processor, implements the electromechanical braking system control method as described in any one of claims 1 to 9.

11. A vehicle, characterized in that: Includes the vehicle control device as described in claim 10.

12. A computer-readable storage medium, characterized in that: The computer-readable storage medium stores computer-executable instructions for causing a computer to perform the electromechanical braking system control method as described in any one of claims 1 to 9.

13. A computer program product, comprising a computer program, characterized in that: When the computer program is executed by the processor, it implements the electromechanical braking system control method as described in any one of claims 1 to 9.

Images