Electronic mechanical braking system control method and device and vehicle

Abstract

The invention discloses a vehicle braking system, and particularly discloses an electronic mechanical braking system control method and device and a vehicle. The electronic mechanical braking system control method comprises the steps that whether the actual slip rate of wheels exceeds an unstable slip rate threshold value or not is judged; when the actual slip rate of the wheels exceeds the unstable slip rate threshold value, the clamping force of the electronic mechanical braking system on the wheels is controlled to be reduced until the actual slip rate of the wheels does not exceed the unstable slip rate threshold value, and the current clamping force of the electronic mechanical braking system on the wheels is marked as non-slip braking force; the electronic mechanical braking system continuously brakes the wheels with the non-slip braking force for a preset time; and controlling the electronic mechanical braking system to increase the clamping force for wheel braking, and repeatedly executing whether the actual slip rate of the wheels exceeds the unstable slip rate threshold value or not, so that the actual slip rate of the vehicle can be effectively controlled within a safe range while the braking force for the wheels can be more accurately improved, and the braking efficiency and safety are improved.

Description

Technical Field

[0001] The invention relates to the configuration of a vehicle suspension, and in particular to an electronic mechanical brake system control method, a control device and a vehicle. Background Art

[0002] The anti-lock braking system converts the sliding friction between the wheels and the ground into static friction as much as possible when the vehicle brakes, thereby reducing the slippage of the vehicle during braking and improving driving safety. When the driver brakes the vehicle and triggers the anti-lock braking system function, some electronic mechanical braking system control methods generally reduce the clamping force on the wheel brake and control the clamping force within a certain range to prevent the wheel from slipping on the ground. This control method has poor control accuracy and affects the braking effect on the wheel. Some electronic mechanical braking systems calculate the slip rate based on the wheel speed and wheel deceleration, and control the slip rate within a single slip rate threshold to prevent the wheel from slipping on the ground. However, in actual driving, the slip rate of the wheel is affected by many factors, such as the adhesion coefficient of the road surface. When the wheel is driving on an environment with a high adhesion coefficient such as an asphalt road surface and driving on an environment with a low adhesion coefficient such as an ice and snow road, the slip rate of the wheel is different. A single slip rate threshold cannot meet the demand for reducing the possibility of wheel locking. In addition, if only a single slip rate threshold is set for judgment and then the clamping force is fed back to control, it means that the clamping force of the wheel is reduced only when the wheel is already in an unstable state. At this time, it is relatively late to reduce the clamping force, and the corresponding clamping force change will be greater, resulting in the change of the wheel slip rate always lagging behind the change of the wheel braking force, that is, the increase in wheel braking force will not immediately lead to an increase in wheel slip rate, and the reduction in wheel braking force will not immediately lead to a decrease in wheel slip rate. Therefore, the actual slip rate of the wheel cannot be controlled within a good range, and the actual wheel slip rate fluctuates significantly and the braking effect is relatively poor. Therefore, a precise and reliable control method for an electronic mechanical braking system is urgently needed. Summary of the invention

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

[0004] A method for controlling an electronic mechanical brake system according to an embodiment of a first aspect of the present invention includes: Obtain the vehicle's wheel speed, wheel deceleration, road adhesion coefficient and driving speed; Calculating an actual wheel slip rate and an unstable slip rate threshold according to the wheel speed, the wheel deceleration, the road adhesion coefficient and the driving speed; determining whether the actual slip rate of the wheel exceeds the unstable slip rate threshold; When the actual slip rate of the wheel exceeds the unstable slip rate threshold, controlling to reduce the clamping force of the electronic mechanical brake system on the wheel until the actual slip rate of the wheel does not exceed the unstable slip rate threshold, and recording the current clamping force of the electronic mechanical brake 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; The electromechanical brake system is controlled to increase the clamping force applied to the wheel brake, and the actual slip rate of the wheel is repeatedly determined to determine whether it exceeds the unstable slip rate threshold.

[0005] The technical solution has at least the following beneficial effects: when braking a vehicle, the wheel speed, wheel deceleration, road adhesion coefficient and driving speed of the vehicle are obtained. Since the wheel speed, wheel deceleration and driving speed will affect the wheel slip rate in real time, the actual wheel slip rate and the unstable slip rate threshold are calculated according to the current wheel speed, wheel deceleration and driving speed of the vehicle. When the actual wheel slip rate exceeds the unstable slip rate threshold, it is necessary to reduce the clamping force of the electronic mechanical braking system on the wheel until the actual wheel slip rate does not exceed the unstable slip rate threshold, which is beneficial to ensuring driving safety. At this time, the clamping force of the current electronic mechanical braking system on the wheel is used to maintain the braking set time, so that the wheel is decelerated in a safe state. Since the electronic mechanical braking system is reduced The clamping force of the mechanical braking system on the wheel may be excessively reduced, and the wheel speed is reduced while maintaining the wheel clamping brake. At this time, the actual wheel slip rate and the unstable slip rate threshold value also change. In order to improve the braking efficiency, the clamping force on the wheel brake is controlled to increase to improve the braking effect on the wheel. In order to ensure driving safety, the above steps of judging whether the wheel actually exceeds the unstable slip rate threshold are repeated to ensure a quick response when the actual wheel slip rate exceeds the unstable slip rate threshold. In this way, by constantly comparing the driving status of the vehicle during braking, the clamping force on the wheel brake can be adjusted in time, so as to more accurately improve the wheel braking force while effectively controlling the actual slip rate of the vehicle within a safe range, thereby improving braking efficiency and safety.

[0006] According to some embodiments of the present invention, the controlling reduces the clamping force of the electronic mechanical brake system on the wheel until the actual slip rate of the wheel does not exceed the unstable slip rate threshold, and further includes: Determining 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 electronic mechanical brake system on the wheel is recorded as the non-slip braking force.

[0007] According to some embodiments of the present invention, the electronic mechanical brake system control method further includes: When the wheel deceleration does not exceed the preset wheel deceleration threshold, the electronic mechanical braking system is executed to continuously brake the wheel with the no-slip braking force for a preset time.

[0008] According to some embodiments of the present invention, the electronic mechanical brake system control method further includes: When the actual wheel slip rate does not exceed the unstable slip rate threshold, the controlling the electromechanical brake system increases the clamping force on the wheel brake.

[0009] According to some embodiments of the present invention, controlling the electromechanical brake system to increase the clamping force of the wheel brake comprises: The reduction amount of the wheel clamping force of the electronic mechanical brake system is recorded as the basic clamping force reduction amount. , is the wheel clamping force at the start, is the road adhesion coefficient, and are preset reference constants respectively; Controlling to increase the non-slip braking force and recording it 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 brake system is controlled to brake the wheel with the adjusted clamping force.

[0010] According to some embodiments of the present invention, the electronic mechanical brake system control method further includes: The controlling of the electronic mechanical brake system to increase the clamping force applied to the wheel brake is repeatedly performed to obtain a plurality of the adjusted clamping forces, wherein the current adjusted clamping force is greater than the previous adjusted clamping force.

[0011] According to some embodiments of the present invention, the electronic mechanical brake system control method further includes: When the increase amount of the no-slip braking force reaches a preset increase threshold, control is performed to reduce the increase amount of the no-slip braking force in the next control of the electromechanical brake system to increase the clamping force applied to the wheel brake.

[0012] According to some embodiments of the present invention, calculating the actual wheel slip rate and the unstable slip rate threshold using the wheel speed, the wheel deceleration and the driving speed includes: The calculation formula of the actual wheel slip rate is: ,in, is the actual wheel slip rate, is the driving speed, is the wheel speed, and a and b are both preset reference constants.

[0013] According to some embodiments of the present invention, calculating the actual wheel slip rate and the unstable slip rate threshold using the wheel speed, the wheel deceleration and the driving speed includes: determining a preset instability coefficient according to the road adhesion coefficient; The unstable slip rate threshold is calculated, and the calculation formula of the unstable slip rate threshold is: ,in, is the unstable slip rate threshold, is the preset slip rate threshold, To preset the instability coefficient, is the wheel deceleration.

[0014] According to some embodiments of the present invention, after controlling the electronic mechanical brake system to increase the clamping force of the wheel brake, the method further includes: determining whether the driving speed reaches a target vehicle speed; When the driving speed does not reach the target vehicle speed, the step of repeatedly determining whether the actual wheel slip rate exceeds the unstable slip rate threshold is performed.

[0015] According to some embodiments of the present invention, the electronic mechanical brake system control method further includes: When the driving speed reaches the target vehicle speed, the electronic mechanical brake system is controlled to stop braking the wheels.

[0016] A vehicle control device according to an embodiment of the second aspect of the present invention 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 electronic mechanical braking system control method of the above embodiment.

[0017] This technical solution has at least the following beneficial effects: the above-mentioned electronic mechanical braking system control method can be implemented as a computer program and tangibly included in a vehicle control device. When the processor uses this computer-readable storage medium to perform the electronic mechanical braking system control method, by continuously comparing the driving state of the vehicle during braking, it can timely feedback and adjust the clamping force of the wheel brake, more accurately improve the wheel braking force, and effectively control the actual slip rate of the vehicle within a safe range, thereby improving braking efficiency and safety.

[0018] A vehicle according to an embodiment of the third aspect of the present invention comprises the above-mentioned vehicle control device.

[0019] This technical solution has at least the following beneficial effects: when a vehicle is braked using this electronic mechanical braking system control method, by continuously comparing the vehicle's driving status during braking, timely feedback can be provided to adjust the clamping force of the wheel brakes, thereby more accurately improving the wheel braking force while effectively controlling the actual slip rate of the vehicle within a safe range, thereby improving braking efficiency and safety.

[0020] According to a fourth aspect of an embodiment of the present invention, a computer-readable storage medium stores computer-executable instructions, and the computer-executable instructions are used to enable a computer to execute the above-mentioned electronic mechanical brake system control method.

[0021] This technical solution has at least the following beneficial effects: the above-mentioned electronic mechanical 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 electronic mechanical braking system control method, by continuously comparing the driving state of the vehicle during braking, it can timely feedback and adjust the clamping force of the wheel brake, more accurately improve the wheel braking force, and effectively control the actual slip rate of the vehicle within a safe range, thereby improving braking efficiency and safety.

[0022] A computer program product according to an embodiment of the fifth aspect of the present invention includes a computer-readable storage medium capable of executing the above.

[0023] This technical solution has at least the following beneficial effects: the above-mentioned electronic mechanical brake system control method is recorded in a computer program product, and the anti-lock control of the electronic mechanical brake system is carried out by using this computer program product. By continuously comparing the driving state of the vehicle during braking, the clamping force of the wheel brake can be adjusted in time, thereby more accurately improving the wheel braking force while effectively controlling the actual slip rate of the vehicle within a safe range, thereby improving braking efficiency and safety.

[0024] Additional aspects and advantages of the present invention will be described in part in the following description and will be apparent from the following description. This disclosure may be apparent or learned through practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly describes the drawings required for use in the description of the embodiments. Obviously, the drawings described are only part of the embodiments of the present invention, not all of the embodiments, and those skilled in the art can also obtain other design solutions and drawings based on these drawings without creative work.

[0026] Figure 1 It is a flow chart of the control method of the electronic mechanical brake system of the present invention.

[0027] Figure 2 This is a flow chart of step S400 of the present invention.

[0028] Figure 3 This is a flow chart of step S600 of the present invention. DETAILED DESCRIPTION

[0029] Embodiments of the present invention are described in detail below, examples of which are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and cannot be understood as limiting the present invention.

[0030] In the description of the present invention, it should be understood that descriptions involving orientations, such as up, down, front, back, left, right, etc., and orientations or positional relationships indicated are based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present invention.

[0031] In the description of the present invention, "several" means one or more, "more" means more than two, "greater than", "less than", "exceed" etc. are understood as not including the number itself, and "above", "below", "within" etc. are understood as including the number itself. If there is a description of "first" or "second", it is only used for the purpose of distinguishing the technical features, and cannot be understood as indicating or implying the relative importance or implicitly indicating the number of the indicated technical features or implicitly indicating the order of the indicated technical features.

[0032] In the description of the present invention, unless otherwise clearly defined, terms such as setting, installing, connecting, etc. should be understood in a broad sense, and technicians in the relevant technical field can reasonably determine the specific meanings of the above terms in the present invention based on the specific content of the technical solution.

[0033] Reference Figure 1 According to an electronic mechanical brake system control method of an embodiment of the first aspect of the present invention, the method comprises but is not limited to the following steps: Step S100, obtaining the wheel speed, wheel deceleration, road adhesion coefficient and driving speed of the vehicle. When the vehicle is driving, the vehicle information is obtained to update the vehicle status. Since the vehicle has different slip rates at different driving speeds and wheel rotation speeds, it is necessary to obtain the wheel speed, wheel deceleration, road adhesion coefficient and driving speed information of the vehicle.

[0034] Step S200, calculating the actual wheel slip rate and the unstable slip rate threshold value according to the wheel speed, wheel deceleration, road adhesion coefficient and driving speed. The actual wheel slip rate and the unstable slip rate threshold value are calculated using the acquired wheel speed, wheel deceleration and driving speed information, so as to timely evaluate the driving stability of the current wheel.

[0035] Step S300, judging whether the actual wheel slip rate exceeds the unstable slip rate threshold. After the vehicle is braked, the current actual wheel slip rate can be compared with the unstable slip rate threshold of whether the vehicle will slip at this time to judge whether there is a risk of slipping during the current driving. When the actual wheel slip rate exceeds the unstable slip rate threshold, the vehicle is at risk of slipping; when the actual wheel slip rate does not exceed the unstable slip rate threshold, the vehicle is not at risk of slipping.

[0036] When the actual wheel slip rate exceeds the unstable slip rate threshold, the process proceeds to step S400, where the clamping force of the electronic mechanical brake system on the wheel is controlled to be reduced until the actual wheel slip rate does not exceed the unstable slip rate threshold, and the current clamping force of the electronic mechanical brake system on the wheel is recorded as the non-slip braking force. When the actual wheel slip rate exceeds the unstable slip rate threshold, the vehicle's braking needs to be intervened. By reducing the clamping force of the electronic mechanical brake system on the wheel, the braking of the wheel is weakened, and the actual wheel slip rate is reduced to a level that does not exceed the unstable slip rate threshold, the risk of vehicle slip can be effectively reduced, which is conducive to ensuring driving safety.

[0037] Step S500, the electronic mechanical braking system brakes the wheel with a non-slip braking force and a preset time. After the wheel is braked for a period of time under a state where the clamping force does not cause the wheel to slip, the wheel speed, wheel deceleration and driving speed are reduced. At this time, the unstable slip rate threshold also changes, and the wheel is not likely to slip. Step S600, control the electronic mechanical brake system to increase the clamping force on the wheel brake, and repeat step S300 to determine whether the actual wheel slip rate exceeds the unstable slip rate threshold. At this time, the clamping force on the wheel brake is increased on the basis of the non-slip braking force, and the wheel brake is continuously strengthened, and the actual wheel slip rate after the braking force is increased needs to be repeatedly judged, so as to improve the braking efficiency of the wheel while ensuring driving safety.

[0038] From the above, it can be seen that when the vehicle is braked, the wheel speed, wheel deceleration, road adhesion coefficient and driving speed of the vehicle are obtained. Since the wheel speed, wheel deceleration and driving speed will affect the wheel slip rate in real time, the actual wheel slip rate and the unstable slip rate threshold are calculated according to the current wheel speed, wheel deceleration and driving speed of the vehicle. When the actual wheel slip rate exceeds the unstable slip rate threshold, it is necessary to reduce the clamping force of the electronic mechanical braking system on the wheel until the actual wheel slip rate does not exceed the unstable slip rate threshold, which is conducive to ensuring driving safety. At this time, the clamping force of the current electronic mechanical braking system on the wheel is used to maintain the braking set time, so that the wheel is decelerated in a safe state. Since the electronic mechanical braking system is reduced The clamping force on the wheel may be excessively reduced, and the wheel speed is reduced while maintaining the wheel clamping brake. At this time, the actual wheel slip rate and the unstable slip rate threshold value also change. In order to improve the braking efficiency, the clamping force on the wheel brake is controlled to increase to improve the braking effect on the wheel. In order to ensure driving safety, the above steps of determining whether the wheel actually exceeds the unstable slip rate threshold are repeated to ensure a quick response when the actual wheel slip rate exceeds the unstable slip rate threshold. In this way, by constantly comparing the driving status of the vehicle during braking, the clamping force on the wheel brake can be adjusted in time to more accurately increase the wheel braking force while effectively controlling the actual slip rate of the vehicle within a safe range, thereby improving braking efficiency and safety.

[0039] In step S400, in order to better enable the vehicle to run stably after the braking force of the wheels is reduced, as shown in FIG. Figure 2 As shown, in this embodiment, step S410 controls the reduction of the clamping force of the electronic mechanical brake system on the wheel until the actual wheel slip rate does not exceed the unstable slip rate threshold, and then enters step S420 to determine whether the wheel deceleration exceeds the 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 electronic mechanical brake system on the wheel as the non-slip braking force. In this way, when judging whether the wheel is running stably, in addition to judging the slip rate, the requirement for wheel deceleration needs to be met. When the actual wheel slip rate does not exceed the unstable threshold, and the wheel deceleration exceeds the preset wheel deceleration threshold, it is judged that the wheel is in a stable state, and then the subsequent action of maintaining the current clamping force on the wheel for braking is performed.

[0040] In step S420, when the wheel deceleration does not exceed the preset wheel deceleration threshold, the process proceeds to step S500, where the electronic mechanical braking system brakes the wheel with a non-slip braking force and a preset time. When the clamping force does not cause the wheel to slip, when the wheel speed decreases, the corresponding wheel deceleration threshold is also reduced, so that the wheel deceleration generated by the current clamping force on the wheel exceeds the wheel deceleration threshold, thereby ensuring the stability of the wheel driving.

[0041] In step S300, when the actual wheel slip rate does not exceed the unstable slip rate threshold, there is no risk of slipping during the current vehicle braking, and the process may proceed to step S600 to control the electronic mechanical brake system to increase the clamping force on the wheel brake. In practical applications, when the actual wheel slip rate does not exceed the unstable slip rate threshold, the process may proceed to step S420 to determine whether the wheel deceleration exceeds the preset wheel deceleration threshold. When the wheel deceleration exceeds the preset wheel deceleration threshold, the process may proceed to step S600 to control the electronic mechanical brake system to increase the clamping force on the wheel brake. When the actual wheel slip rate does not exceed the unstable slip rate threshold, the clamping force on the wheel brake may be further increased, thereby enhancing the braking of the wheel.

[0042] In step S600, the electronic mechanical brake system is controlled to increase the clamping force on the wheel brake, such as Figure 3 As shown, including but not limited to the following steps: Step S610, recording the amount of reduction in the wheel clamping force of the electronic mechanical brake system as the basic clamping force reduction amount. , is the wheel clamping force at the start, is the road adhesion coefficient, and are preset reference constants respectively. The reduction of basic clamping force is related to the wheel clamping force at the moment when the unstable condition is met, and the calculation formula is as follows: . is the basic clamping force reduction, is the wheel clamping force at the start time, c is a preset reference constant, which may be between 0.1 and 0.3, preferably 0.2; d is a preset reference constant, which may be between 0.05 and 0.2, preferably 0.1. is the road adhesion coefficient, and its value range can be between 0.01 and 1. For example, on an asphalt road, the road adhesion coefficient is about 0.8, and on an ice and snow road, the road adhesion coefficient is about 0.1. When the unstable condition is met, the current clamping force value is obtained, and the clamping force value can reflect the current road condition to a certain extent. The basic clamping force reduction is related to the clamping force value. When the road adhesion coefficient is higher, the wheel speed change is smaller than the wheel speed change on a low-adhesion road, so the required basic clamping force reduction is larger. When the road adhesion coefficient is lower, on the contrary, the wheel speed change is larger than the wheel speed change on a high-adhesion road, so the required basic clamping force reduction is smaller.

[0043] Step S620, control the increase of the non-slip braking force and record it as the adjusted clamping force, and the increase of the non-slip braking force is not greater than the reduction of the basic clamping force. Since the actual slip rate of the wheel when reducing the wheel clamping force exceeds the unstable slip rate threshold, that is, the wheel clamping force is too large at this time, the total clamping force reduction when the wheel clamping force is reduced to the non-slip braking force is recorded as the basic clamping force reduction. When the wheel clamping force needs to be increased, the clamping force is increased by no more than the basic force reduction on the basis of the non-slip braking force, so that the increase of the clamping force can be better controlled to avoid the situation where the clamping force is too large and causes the wheel to slip.

[0044] Step S630, controlling the electronic mechanical brake system to brake the wheel with the adjusted clamping force, that is, further increasing the clamping force to brake the wheel on the basis of the non-slip braking force, in an attempt to enhance the braking of the wheel and improve the braking efficiency.

[0045] When performing step S600, there may be a situation where a single increase in the clamping force causes the actual wheel slip rate to exceed the unstable slip rate threshold, or after a single increase in the clamping force, the actual wheel slip rate has not exceeded the unstable slip rate threshold, then the process will re-enter step S600 and perform the operation of increasing the clamping force again, so that step S600 will be performed multiple times, and the electronic mechanical brake system will be repeatedly controlled to increase the clamping force on the wheel to obtain multiple adjusted clamping forces, and the current adjusted clamping force is greater than the previous adjusted clamping force. In this way, the clamping force is gradually increased to form a step-by-step increase, which is conducive to avoiding the problem of a sudden increase in the slip rate due to an excessively fast increase in the clamping force, and improving the braking stability.

[0046] Furthermore, when the step S600 is executed multiple times, when the increase in the non-slip braking force reaches a preset increase threshold, the control is to reduce the increase in the non-slip braking force in the clamping force of the wheel brake that is increased by the next control of the electronic mechanical brake system. In this braking method, the increase in the wheel brake clamping force is large at the initial stage, and the wheel braking force can be quickly increased at this time. In the later stage, as the wheel brake clamping force gradually increases, the wheel is more likely to slip, so the increase in the wheel brake clamping force is reduced, so the accuracy of the clamping force control can be improved. For example, on the basis of the no-slip braking force, the clamping force is increased multiple times until the clamping force increases to 75% of the basic clamping force reduction. In this process, the increase in the clamping force is the initial stage, and the increase in the clamping force each time is relatively large. For example, the increase in the clamping force each time can be 0.1 to 0.3 of the basic clamping force reduction, and preferably, it can be 0.2 of the basic clamping force reduction; when the clamping force continues to be increased, the clamping force increases from 75% of the basic clamping force reduction to 100% of the basic clamping force reduction, for example, the increase in the clamping force each time can be 0.1 to 0.3 of the basic clamping force reduction, but the increase in the clamping force each time is less than the increase in the clamping force at the initial step, and preferably, it can be 0.15 of the basic clamping force reduction. This can improve the control of the step-by-step increase in the clamping force, thereby further improving the braking stability.

[0047] In step S200, the calculation formula of the actual wheel slip rate is: ,in, is the actual wheel slip rate, is the driving speed, is the wheel speed, a and b are both preset reference constants, a is between 0 and 10, preferably, a is 6, b is between 1 and 1.2, preferably, b is 1.1. In this calculation formula, when the driving speed is relatively low, the slip ratio obtained has a reduced effect, thereby allowing a larger slip ratio, thereby enhancing the braking force and improving the wheel deceleration. When the driving speed is relatively high, the slip ratio has an effect of amplifying, making the change of the slip ratio more sensitive, thereby requiring the braking force to be gradually reduced to improve the braking stability of the vehicle at high speed.

[0048] In step S200, a preset instability coefficient is first determined according to the road adhesion coefficient, and then an unstable slip rate threshold is calculated. The calculation formula of the unstable slip rate threshold is: ,in, is the unstable slip rate threshold, is the preset slip rate threshold, To preset the instability coefficient, is the wheel deceleration, The value of is generally between 0.005 and 0.02. The unstable slip rate threshold takes into account the change of wheel deceleration. Wheel deceleration reflects the speed of wheel speed change. 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 quickly. When the wheel deceleration is large, since the wheel deceleration is a negative value, the unstable slip rate threshold calculated in real time according to the above formula is relatively smaller, which can allow the wheel to recognize the possible unstable state in advance, reduce the clamping force in advance, and improve the braking effect. The speed of wheel speed change is related to the preset instability coefficient, and the adhesion coefficient of the road surface affects the preset instability coefficient. On low-adhesion roads such as ice and snow roads, the adhesion between the tire and the ground is very small, so the wheel is more likely to lock. A smaller braking force will produce a larger slip rate. It is necessary to set the unstable slip rate threshold lower and reduce the clamping force in advance. Therefore, a larger value of the preset instability coefficient is taken, so that the unstable slip rate threshold calculated according to the formula is lower, which is more conducive to control on low-adhesion roads and effectively solves the problem that a single slip rate threshold cannot be changed and adjusted according to different road environments.

[0049] The preset instability coefficient value is related to the road adhesion coefficient. When the road adhesion coefficient is less than 0.2, the preset instability coefficient value is 0.02; when the road adhesion coefficient is between 0.2 and 0.8, the preset instability coefficient value is 0.01; when the road adhesion coefficient is greater than 0.8, the preset instability coefficient value is 0.005.

[0050] Assuming that on an icy and snowy road, the road adhesion coefficient is about 0.1, and a clamping force of 10 kN can achieve the best braking effect on the wheel on this road, but in actual vehicles, the change of wheel slip rate always lags behind the change of wheel braking force. The increase of wheel braking force will not immediately lead to an increase in wheel slip rate, and the reduction of wheel braking force will not immediately lead to a decrease in wheel slip rate. Therefore, when the wheel clamping force is 10 kN, the wheel still has no slip rate, and when the wheel clamping force is 11 kN, the wheel slip rate increases to a relatively large level. However, on low-adhesion roads, the wheel speed changes very quickly (that is, the wheel deceleration is very large), and the wheel is easy to lock. If the influence of wheel deceleration is not considered, the clamping force will be reduced only when it is 11 kN, which will make the wheel more likely to lock. The unstable slip rate threshold is calculated by wheel deceleration and instability coefficient, and the slip rate threshold on low-adhesion roads is reduced. When the wheel clamping force is 10.5 kN, the clamping force is reduced in advance, which can effectively reduce the possibility of wheel locking and improve the braking effect.

[0051] In step S600, after controlling the electronic mechanical brake system to increase the clamping force on the wheel brake, 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 brake to, for example, the driving speed is 0. When the driving speed does not reach the target speed, the process is repeated to determine whether the actual wheel slip rate exceeds the unstable slip rate threshold. When the driving speed does not reach the target speed, the next clamping force judgment action is required. When the driving speed reaches the target speed, the process proceeds to step S800 to control the electronic mechanical brake system to stop braking the wheel. At this point, the vehicle has been braked and no braking operation is required.

[0052] In summary, multiple embodiments of using the electromechanical brake system control method in different situations are provided here: In the first embodiment, when the driver is driving at a certain speed and steps on the brake pedal, and the actual slip rate of the wheel is greater than the unstable slip rate threshold, the wheel enters an unstable state, and the amount of clamping force reduction is determined based on the current clamping force. At this time, the electronic mechanical brake system is controlled to release. After the release is completed, the clamping force holding stage is entered, which lasts for a set time, for example, 0.1 seconds. The wheel is in a stable state at this time, and the wheel enters the clamping process. The basic clamping force reduction is determined based on the sum of the clamping force reduction in the last release process, and the wheel is clamped in sequence according to the step-by-step increasing clamping force change gradient. When the wheel meets the unstable condition again, the wheel enters the release state again and repeats the above process. The cycle of release, holding, and clamping is performed in this way until the vehicle stops.

[0053] In the second embodiment, when the driver is driving at a certain speed and steps on the brake pedal, and the actual slip rate of the wheel is greater than the unstable slip rate threshold, the wheel enters an unstable state, and the amount of clamping force reduction is determined according to the current clamping force, and the electronic mechanical brake system is controlled to release. After the release is completed, the clamping force holding stage is entered, and the clamping force reduction is determined according to the current clamping force. After 0.1 seconds, the wheel is still in an unstable state, and the wheel enters a secondary release process, and the amount of clamping force reduction is determined according to the current clamping force. After the secondary release is completed, the clamping force holding stage is entered, and the wheel is in a stable state after 0.1 seconds. The wheel enters the clamping process, and the basic clamping force reduction is determined according to the sum of the clamping force reduction in the last release process, and the clamping is performed in sequence according to the step-by-step increasing clamping force change gradient. When the wheel meets the unstable condition again, the wheel enters the release state again, and the above process is repeated. This cycle of release, holding, and clamping is repeated until the vehicle stops.

[0054] In the third embodiment, when the driver is driving at a certain speed and steps on the brake pedal, and the actual slip rate of the wheel is greater than the unstable slip rate threshold, the wheel enters an unstable state, and the amount of clamping force reduction is determined according to the current clamping force, and the electronic mechanical brake system is controlled to release at this time. After the release is completed, the clamping force holding stage is entered, and the set time is continued, for example, after 0.1 seconds, the wheel is in a stable state at this time, and the wheel enters the clamping process, and the basic clamping force reduction is determined according to the sum of the clamping force reduction in the last release process, and the wheel is clamped in sequence according to the step-by-step increasing clamping force change gradient. When the wheel clamping force increases, the wheel is still in a stable state, and the wheel is clamped with a larger clamping force change gradient until the wheel meets the unstable condition, and the wheel enters the release state again, and the above process is repeated. This release, holding, and clamping cycle is repeated until the vehicle stops.

[0055] A vehicle control device according to an embodiment of the second aspect of the present invention 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, the electronic mechanical brake system control method of the above embodiment is implemented.

[0056] The above-mentioned electronic mechanical braking system control method can be implemented as a computer program and be tangibly included in the vehicle control device. When the processor uses this computer-readable storage medium to perform the electronic mechanical braking system control method, by constantly comparing the driving status of the vehicle during braking, it can timely feedback and adjust the clamping force of the wheel brake, more accurately improve the wheel braking force, and effectively control the actual slip rate of the vehicle within a safe range, thereby improving braking efficiency and safety.

[0057] Take the example that the processor and memory in the vehicle control device can be connected through 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. In addition, the memory may include a high-speed random access memory, and may also include a non-transitory memory, such as at least one disk memory, a flash memory device, or other non-transitory solid-state storage device. In some embodiments, the memory may optionally include a memory remotely arranged relative to the control processor, and these remote memories may be connected to the control device via a network.

[0058] A vehicle according to an embodiment of the third aspect of the present invention includes the above-mentioned vehicle control device. The vehicle can be a private car, such as a sedan, SUV, MPV or pickup truck. The vehicle can also be an operating vehicle, such as a van, bus, small truck or large trailer. The vehicle needs to have an electric motor that can output power or store mechanical energy as a generator. When the vehicle is a new energy vehicle, it can be a hybrid vehicle or a pure electric vehicle.

[0059] When a vehicle brakes using this electronic mechanical brake system control method, by constantly comparing the vehicle's driving status during braking, timely feedback can be provided to adjust the clamping force of the wheel brakes, thereby more accurately improving the wheel braking force while effectively controlling the vehicle's actual slip rate within a safe range, thereby improving braking efficiency and safety.

[0060] According to a computer-readable storage medium of an embodiment of the fourth aspect of the present invention, the computer-readable storage medium stores computer-executable instructions, and the computer-executable instructions are used to enable a computer to execute the above-mentioned electronic mechanical brake system control method.

[0061] The above-mentioned electronic mechanical braking system control method can be implemented as a computer program and tangibly included in a computer-readable storage medium. When the processor uses this computer-readable storage medium to perform the electronic mechanical braking system control method, by continuously comparing the driving state of the vehicle during braking, it can timely feedback and adjust the clamping force of the wheel brake, more accurately improve the wheel braking force, and effectively control the actual slip rate of the vehicle within a safe range, thereby improving braking efficiency and safety.

[0062] It is worth noting that since the computer-readable storage medium of the embodiment of the present invention can execute the anti-lock control method of any of the above-mentioned embodiments, the specific implementation methods and technical effects of the computer-readable storage medium of the embodiment of the present invention can refer to the specific implementation methods and technical effects of the anti-lock control method of any of the above-mentioned embodiments.

[0063] A computer program product according to an embodiment of the fifth aspect of the present invention includes a computer-readable storage medium capable of executing the above.

[0064] It is worth noting that since the computer program product of the embodiment of the present invention can execute the electronic mechanical brake system control method of any of the above-mentioned embodiments, the specific implementation methods and technical effects of the computer program product of the embodiment of the present invention can refer to the specific implementation methods and technical effects of the electronic mechanical brake system control method of any of the above-mentioned embodiments.

[0065] The computer program product records the above-mentioned electronic mechanical brake system control method. By using this computer program product to control the anti-lock braking of the electronic mechanical brake system, the clamping force of the wheel brake can be adjusted in time by continuous comparison of the driving state of the vehicle during braking, so as to more accurately improve the wheel braking force while effectively controlling the actual slip rate of the vehicle within a safe range, thereby improving the braking efficiency and safety. It can be understood by those of ordinary skill in the art that all or some steps and systems in the method disclosed above can be implemented as software, firmware, hardware and appropriate combinations thereof. Some physical components or all physical components can be implemented as software executed by a processor, such as a central processing unit, a digital signal processor or a microprocessor, or implemented as hardware, or implemented as an integrated circuit, such as an application-specific integrated circuit. Such software can be distributed on a computer-readable medium, which can include a computer storage medium (or non-transitory medium) and a communication medium (or transient medium). As is well known to those of ordinary skill in the art, the term computer storage medium 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 technology, CD-ROM, digital versatile disks (DVD) or other optical disk storage, magnetic cassettes, magnetic tapes, magnetic disk storage or other magnetic storage devices, or any other medium that can be used to store the desired information and can be accessed by a computer. In addition, 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 a modulated data signal such as a carrier wave or other transport mechanism, and may include any information delivery media.

[0066] The preferred embodiments of the present invention are specifically described above, but the invention is not limited to the embodiments. Those skilled in the art may make various equivalent modifications or substitutions without violating the spirit of the invention. These equivalent modifications or substitutions are all included in the scope defined by the claims of this application.

Claims

1. A method for controlling an electronic mechanical brake system, characterized in that: include: Obtain the vehicle's wheel speed, wheel deceleration, road adhesion coefficient and driving speed; Calculating an actual wheel slip rate and an unstable slip rate threshold according to the wheel speed, the wheel deceleration, the road adhesion coefficient and the driving speed; determining whether the actual slip rate of the wheel exceeds the unstable slip rate threshold; When the actual slip rate of the wheel exceeds the unstable slip rate threshold, controlling to reduce the clamping force of the electronic mechanical brake system on the wheel until the actual slip rate of the wheel does not exceed the unstable slip rate threshold, and recording the current clamping force of the electronic mechanical brake 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; The electromechanical brake system is controlled to increase the clamping force applied to the wheel brake, and the actual slip rate of the wheel is repeatedly determined to determine whether it exceeds the unstable slip rate threshold.

2. The method for controlling an electronic mechanical brake system according to claim 1, characterized in that: The control reduces the clamping force of the electronic mechanical brake system on the wheel until the actual slip rate of the wheel does not exceed the unstable slip rate threshold, and further includes: Determining 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 electronic mechanical brake system on the wheel is recorded as the non-slip braking force.

3. The method for controlling an electronic mechanical brake system according to claim 2, characterized in that: The electronic mechanical brake system control method further includes: When the wheel deceleration does not exceed the preset wheel deceleration threshold, the electronic mechanical braking system is executed to continuously brake the wheel with the no-slip braking force for a preset time.

4. The method for controlling an electronic mechanical brake system according to claim 1, characterized in that: The electronic mechanical brake system control method further includes: When the actual wheel slip rate does not exceed the unstable slip rate threshold, the controlling the electromechanical brake system increases the clamping force on the wheel brake.

5. The method for controlling an electronic mechanical brake system according to claim 4, characterized in that: The controlling the electronic mechanical brake system to increase the clamping force of the wheel brake comprises: The amount of reduction in the wheel clamping force of the electronic mechanical brake system is recorded as a basic clamping force reduction amount. , is the wheel clamping force at the start, is the road adhesion coefficient, and are preset reference constants respectively; Controlling to increase the non-slip braking force and recording it 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 brake system is controlled to brake the wheel with the adjusted clamping force.

6. The method for controlling an electronic mechanical brake system according to claim 5, characterized in that: The electronic mechanical brake system control method further includes: The controlling of the electronic mechanical brake system to increase the clamping force applied to the wheel brake is repeatedly performed to obtain a plurality of the adjusted clamping forces, wherein the current adjusted clamping force is greater than the previous adjusted clamping force.

7. The method for controlling an electronic mechanical brake system according to claim 6, characterized in that: The electronic mechanical brake system control method further includes: When the increase amount of the no-slip braking force reaches a preset increase threshold, control is performed to reduce the increase amount of the no-slip braking force in the next control of the electromechanical brake system to increase the clamping force applied to the wheel brake.

8. The method for controlling an electronic mechanical brake system according to claim 1, characterized in that: Calculating the actual wheel slip rate and the unstable slip rate threshold using the wheel speed, the wheel deceleration and the driving speed includes: The calculation formula of the actual wheel slip rate is: ,in, is the actual wheel slip rate, is the driving speed, is the wheel speed, and a and b are both preset reference constants.

9. The method for controlling an electronic mechanical brake system according to claim 1, characterized in that: Calculating the actual wheel slip rate and the unstable slip rate threshold using the wheel speed, the wheel deceleration and the driving speed includes: determining a preset instability coefficient according to the road adhesion coefficient; The unstable slip rate threshold is calculated, and the calculation formula of the unstable slip rate threshold is: ,in, is the unstable slip rate threshold, is the preset slip rate threshold, To preset the instability coefficient, is the wheel deceleration.

10. The method for controlling an electronic mechanical brake system according to claim 1, characterized in that: After controlling the electronic mechanical brake system to increase the clamping force of the wheel brake, the method further includes: determining whether the driving speed reaches a target vehicle speed; When the driving speed does not reach the target vehicle speed, the step of repeatedly determining whether the actual wheel slip rate exceeds the unstable slip rate threshold is performed.

11. The method for controlling an electronic mechanical brake system according to claim 10, characterized in that: The electronic mechanical brake system control method further includes: When the driving speed reaches the target vehicle speed, the electronic mechanical brake system is controlled to stop braking the wheels.

12. A vehicle control device, characterized in that: The invention comprises a memory, a processor and a program stored in the memory and executable on the processor, wherein when the program is executed by the processor, the electronic mechanical brake system control method according to any one of claims 1 to 11 is implemented.

13. A vehicle, characterized in that: Comprising the vehicle control device as claimed in claim 12.

14. A computer-readable storage medium, characterized in that: The computer-readable storage medium stores computer-executable instructions, and the computer-executable instructions are used to enable a computer to execute the electronic mechanical brake system control method according to any one of claims 1 to 11.

15. A computer program product, characterized in that: The invention comprises a computer readable storage medium capable of executing the method of claim 14.

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