Multi-axle vehicle anti-lock control method and device

Abstract

The invention relates to the technical field of vehicles, and provides an anti-lock control method for a multi-axle vehicle. The method comprises the following steps: S1, acquiring driving state information of wheels, wherein the driving state information comprises a slippage degree, a wheel speed deceleration and a wheel speed vector; s2, under the condition that the slippage degree and the wheel speed deceleration meet the first condition, the ABS adjusting device enters a pressure reduction mode; s3, under the condition that the wheel speed vector meets a second condition, the ABS adjusting device enters a pressure maintaining mode; s4, under the condition that the slippage degree and the wheel speed vector meet a third condition, the ABS adjusting device enters a pressurization mode; and S5, anti-lock control is conducted on the multi-axle vehicle according to the pressure reduction mode, the pressure maintaining mode and the pressure increasing mode. According to the method, the problem that some wheels are easy to lock due to the deviation of empirical values and load distribution in the prior art is solved, the adaptability and the braking safety of the whole vehicle chassis can be greatly improved, and the braking performance of the vehicle is further improved.

Description

Technical Field

[0001] The present invention relates to the technical field of vehicles, and in particular to an anti-lock braking control method and device for a multi-axle vehicle. Background Art

[0002] The function of ABS is to control the braking force of the brakes when the car brakes, so that the wheels are on the border of rolling and slipping to avoid wheel locking problems, thereby ensuring that the friction between the wheels and the ground is at the maximum value, achieving the maximum braking force and vehicle deceleration.

[0003] Most ABS is used to adjust a single wheel speed signal, especially in the field of multi-axle commercial vehicles. In order to save costs, an axis that is prone to locking is often used as the basis for ABS adjustment, and the braking force of multiple axes is adjusted synchronously. With this arrangement, the axis that is prone to locking will change when facing different upper parts and different load distributions. When the axis that is prone to locking is different from the axis where the wheel speed sensor is arranged empirically, it will cause the problem of locking of the axis without the wheel speed sensor. Summary of the invention

[0004] The present invention provides an anti-lock control method and device for a multi-axle vehicle, which are used to solve the problem in the prior art that some wheels are prone to locking due to deviations in empirical values ​​and load distribution, and realize an anti-lock control method that can cope with the above problem, greatly increase the adaptability of the vehicle chassis and braking safety, and thus improve the braking performance of the vehicle.

[0005] The present invention provides an anti-lock braking control method for a multi-axle vehicle, which is applied to a multi-axle vehicle. The multi-axle vehicle includes a braking system having a plurality of channels, each of which controls the braking of at least one wheel, and each of which is provided with an ABS adjustment device. The anti-lock braking control method for a multi-axle vehicle includes: Acquiring driving state information of the wheel, the driving state information including slip degree, wheel speed deceleration and wheel speed vector; When the slip degree and the wheel speed deceleration satisfy a first condition, the ABS adjustment device enters a decompression mode and determines whether the wheel speed vector satisfies a second condition; wherein the first condition is that the slip degree is greater than a first preset slip degree threshold, or the slip degree is greater than a second preset slip degree threshold and the wheel speed deceleration is less than a preset deceleration threshold; the first preset slip degree threshold is greater than the second preset slip degree threshold; the second condition is that the wheel speed vector is upward; When the wheel speed vector satisfies the second condition, the ABS adjustment device enters the pressure holding mode and determines whether the slip degree and the wheel speed vector satisfy a third condition; wherein the third condition is that the wheel speed vector is downward and the slip degree is less than a third preset slip degree threshold; and the second preset slip degree threshold is greater than the third preset slip degree threshold; When the slip degree and the wheel speed vector satisfy the third condition, the ABS adjustment device enters a boost mode; Anti-lock control is performed on the multi-axle vehicle according to the pressure reduction mode, the pressure maintenance mode and the pressure increase mode.

[0006] According to a multi-axle vehicle anti-lock braking control method provided by the present invention, obtaining the slip degree includes: Obtain the initial wheel speed of the cycle, the expected deceleration of the cycle, the cycle period, the current wheel speed, the current vehicle speed and the wheel rolling radius; Determine a nominal wheel speed according to the cycle initial wheel speed, the cycle expected deceleration, the cycle period, the current wheel speed, the current vehicle speed and the wheel rolling radius; The slip degree is determined according to the nominal wheel speed and the current wheel speed.

[0007] According to a multi-axle vehicle anti-lock control method provided by the present invention, the obtaining of the cyclic expected deceleration comprises: In the case where the multi-axle vehicle is in the first braking cycle, determining the expected deceleration of the cycle by a brake electronic control unit; When the multi-axle vehicle is not in the first braking cycle, the initial wheel speed of the previous cycle, the ending wheel speed of the previous cycle and the period of the previous cycle are obtained, and the expected deceleration of the cycle is determined based on the initial wheel speed of the previous cycle, the ending wheel speed of the previous cycle and the period of the previous cycle.

[0008] According to a multi-axle vehicle anti-lock control method provided by the present invention, when the multi-axle vehicle is not in the first braking cycle, the cycle expected deceleration is determined by formula (1); (1) in, represents the expected wheel speed deceleration of wheel i; represents the initial wheel speed of wheel i in the previous cycle; represents the wheel speed of wheel i at the end of the previous cycle; Indicates the cycle period of the previous cycle.

[0009] According to a multi-axle vehicle anti-lock control method provided by the present invention, the nominal wheel speed is determined by formula (2); (2) in, Indicates the nominal wheel speed; Indicates the current wheel speed; Indicates the initial wheel speed of the cycle; t Indicates the cycle period; Indicates the current vehicle speed; Indicates the wheel rolling radius.

[0010] According to a multi-axle vehicle anti-lock control method provided by the present invention, the slip degree is determined by formula (3); (3) in, Indicates the degree of slip.

[0011] According to a multi-axle vehicle anti-lock control method provided by the present invention, obtaining the wheel speed vector includes: Obtaining an initial wheel speed vector of the wheel corresponding to the channel; Obtaining the initial wheel speed of the wheel corresponding to the channel; Continuously obtaining the current wheel speeds of k wheels; pass k The wheel speed vector is determined by the current wheel speed and the initial wheel speed.

[0012] According to a multi-axle vehicle anti-lock control method provided by the present invention, the k The current wheel speed and the initial wheel speed are used to determine a wheel speed vector, including: pass k determining whether the wheel speed vector is downward based on the current wheel speed and the initial wheel speed, and if the wheel speed vector is downward, determining that the wheel speed vector is downward; In the case where the wheel speed vector is not downward, k The current wheel speed and the initial wheel speed are used to determine whether the wheel speed vector is upward. If the wheel speed vector is upward, it is determined that the wheel speed vector is upward; otherwise, it is determined that the wheel speed vector is downward.

[0013] According to a multi-axle vehicle anti-lock control method provided by the present invention, whether the wheel speed vector is downward is determined by formula (4); whether the wheel speed vector is upward is determined by formula (5); (4) (5) in, Indicates the first current wheel speed; Indicates the kth current wheel speed.

[0014] The present invention also provides an anti-lock braking control device for a multi-axle vehicle, comprising the braking system described in any one of the above embodiments.

[0015] The multi-axle vehicle anti-lock control method provided by the present invention can make the most appropriate adjustment according to the actual state of each wheel through the independent operation of the ABS adjustment device of each channel, which not only improves the adaptability of the multi-axle vehicle under different road conditions and load distribution, but also effectively avoids the risk of other axles locking due to reliance on the wheel speed signal of a single axle in the traditional solution. In addition, the method can solve the problem of some wheels being easily locked due to the deviation of experience value and load distribution in traditional multi-axle vehicles without adding ABS adjustment devices and channels. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] In order to more clearly illustrate the technical solutions in the present invention or the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0017] Figure 1 This is one of the flow charts of the multi-axle vehicle anti-lock braking control method provided by the present invention.

[0018] Figure 2 This is the second flow chart of the multi-axle vehicle anti-lock braking control method provided by the present invention.

[0019] Figure 3 This is the third flow chart of the multi-axle vehicle anti-lock braking control method provided by the present invention.

[0020] Figure 4 This is the fourth flow chart of the multi-axle vehicle anti-lock braking control method provided by the present invention.

[0021] Figure 5 This is the fifth flow chart of the multi-axle vehicle anti-lock braking control method provided by the present invention.

[0022] Figure 6 This is the sixth flow chart of the multi-axle vehicle anti-lock braking control method provided by the present invention.

[0023] Figure 7 The present invention is a schematic structural diagram of a multi-axle vehicle anti-lock control device applied to a dual rear axle three-axle vehicle.

[0024] Figure 8 The present invention is a schematic structural diagram of a multi-axle vehicle anti-lock control device applied to a dual front axle three-axle vehicle.

[0025] Fig. 9 The present invention is a schematic structural diagram of a multi-axle vehicle anti-lock control device applied to a three-axle vehicle with double front axles and double rear axles.

[0026] Reference numerals: 1.1: first wheel; 1.2: second wheel; 1.3: third wheel; 1.4: fourth wheel; 1.5: fifth wheel; 1.6: sixth wheel; 1.7: seventh wheel; 1.8: eighth wheel; 2.1: first gear ring; 2.2: second gear ring; 2.3: third gear ring; 2.4: fourth gear ring; 2.5: fifth gear ring; 2.6: sixth gear ring; 2.7: seventh gear ring; 2.8: eighth gear ring; 3.1: First wheel speed sensor; 3.2: Second wheel speed sensor; 3.3: Third wheel speed sensor; 3.4: Fourth wheel speed sensor; 3.5: Fifth wheel speed sensor; 3.6: Sixth wheel speed sensor; 3.7: Seventh wheel speed sensor; 3.8: Eighth wheel speed sensor; 4.1: first energy storage device; 4.2: second energy storage device; 5: Brake pedal; 6.1: first brake pressure building module; 6.2: second brake pressure building module; 7.1: first ABS regulating device; 7.2: second ABS regulating device; 7.3: third ABS regulating device; 7.4: fourth ABS regulating device 7.4; 8.1: first brake actuating device; 8.2: second brake actuating device; 8.3: third brake actuating device; 8.4: fourth brake actuating device; 9.1: first brake actuator with parking function; 9.2: second brake actuator with parking function; 9.3: third brake actuator with parking function; 9.4: fourth brake actuator with parking function; 10: control unit; 11.1: first hydraulic circuit; 11.2: second hydraulic circuit; 12.1: Front left fl Channel; 12.2: front right fr Channel; 12.3: Left rear rl Channel; 12.4: Right rear rr aisle. DETAILED DESCRIPTION

[0027] The following embodiments of the present invention are described in further detail in conjunction with the accompanying drawings and examples. The following examples are used to illustrate the present invention, but are not intended to limit the scope of the present invention.

[0028] In the description of the embodiments of the present invention, it should be noted that the terms "center", "longitudinal", "lateral", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside" and the like indicate positions or positional relationships based on the positions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the embodiments of the present invention and simplifying the description, and do not indicate or imply that the devices or elements referred to must have a specific orientation, be constructed and operate in a specific orientation, and therefore cannot be understood as limitations on the embodiments of the present invention. In addition, the terms "first", "second", and "third" are used for descriptive purposes only and cannot be understood as indicating or implying relative importance.

[0029] In the description of the embodiments of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "connected" and "connection" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium. For ordinary technicians in this field, the specific meanings of the above terms in the embodiments of the present invention can be understood according to specific circumstances.

[0030] In the embodiments of the present invention, unless otherwise clearly specified and limited, the first feature being "above" or "below" the second feature may mean that the first and second features are in direct contact, or the first and second features are in indirect contact through an intermediate medium. Moreover, the first feature being "above", "above" and "above" the second feature may mean that the first feature is directly above or obliquely above the second feature, or simply means that the first feature is higher in level than the second feature. The first feature being "below", "below" and "below" the second feature may mean that the first feature is directly below or obliquely below the second feature, or simply means that the first feature is lower in level than the second feature.

[0031] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the embodiment of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine the different embodiments or examples described in this specification and the features of the different embodiments or examples, without contradiction.

[0032] Combine the following Figure 1-Figure 6 The anti-lock braking control method of a multi-axle vehicle of the present invention is described.

[0033] Reference Figure 1 In some embodiments of the present invention, a multi-axle vehicle anti-lock braking control method provided by the present invention is applied to a multi-axle vehicle, the multi-axle vehicle includes a braking system with multiple channels, each channel controls the braking of at least one wheel, and each channel is provided with an ABS adjustment device.

[0034] The multi-axle vehicle anti-lock braking control method comprises the following steps: S1. Acquire the driving state information of the wheel, where the driving state information includes the slip degree, wheel speed deceleration and wheel speed vector; wherein the wheel speed deceleration can be directly measured.

[0035] S2: If the slip degree and wheel speed deceleration meet the first condition, the vehicle body is judged to be in an unstable risk state, and the ABS adjustment device enters the decompression mode; if the slip degree and wheel speed deceleration do not meet the first condition, the vehicle body is judged to be in a stable state, and there is no need to enter the ABS mode. Then determine whether the wheel speed vector meets the second condition; Among them, the first condition is that the slip degree is greater than the first preset slip degree threshold, or the slip degree is greater than the second preset slip degree threshold and the wheel speed deceleration is less than the deceleration preset threshold; the first preset slip degree threshold is greater than the second preset slip degree threshold; the second condition is that the wheel speed vector is upward. The first preset slip degree threshold and the second preset slip degree threshold are actually two preset slip degrees. The first preset slip degree threshold and the second preset slip degree threshold are not a fixed value. They will change according to factors such as vehicle speed, vehicle deceleration, ground adhesion coefficient, axle load, engine torque, vehicle speed ratio, etc. The first preset slip degree threshold and the second preset slip degree threshold can be obtained through calibration.

[0036] S3: If the wheel speed vector meets the second condition, the vehicle body is judged to be in an instability risk recovery state, and the ABS adjustment device enters the pressure maintenance mode. If not, the ABS adjustment device continues to maintain the pressure reduction mode. Then determine whether the slip degree and wheel speed vector meet the third condition; Among them, the third condition is that the wheel speed vector is downward and the slip degree is less than the third preset threshold of the slip degree; the second preset threshold of the slip degree is greater than the third preset threshold of the slip degree; the setting of the third preset threshold of the slip degree can refer to the first preset threshold of the slip degree and the second preset threshold of the slip degree, and will not be repeated here.

[0037] S4. When the slip degree and the wheel speed vector satisfy the third condition, it is determined that the vehicle body state is restoring the braking limit state, and the ABS regulating device enters the boost mode; if not, the ABS regulating device continues to maintain the pressure holding mode.

[0038] S5. Anti-lock control is performed on the multi-axle vehicle according to the pressure reduction mode, the pressure maintenance mode and the pressure increase mode.

[0039] The present invention first obtains the driving status information of each wheel, including the degree of slip, wheel speed deceleration and wheel speed vector. Based on this information, the vehicle body state can be dynamically evaluated. When the degree of slip or wheel speed deceleration is detected to exceed the preset safety threshold, the vehicle is considered to be in an unstable risk state. At this time, the ABS adjustment device will respond quickly and start the decompression mode to reduce the braking force to prevent the wheel from locking. If the subsequent analysis shows that the wheel speed vector is on an upward trend, indicating that the wheel begins to resume rolling, the system will switch to the pressure-maintaining mode to maintain the current braking force level and promote the smooth deceleration of the vehicle. When the degree of slip further decreases and the wheel speed vector turns to decrease, the system recognizes that the braking limit state has been restored. At this time, the boost mode will be activated to gradually increase the braking force until the vehicle stops completely.

[0040] In this method, the ABS adjustment device of each channel can operate independently and make the most appropriate adjustment according to the actual state of each wheel, which not only improves the adaptability of multi-axle vehicles under different road conditions and load distribution, but also effectively avoids the risk of other axles locking due to reliance on the wheel speed signal of a single axle in the traditional solution. In addition, this method can solve the problem of some wheels being prone to locking due to the deviation of experience value and load distribution in traditional multi-axle vehicles without adding ABS adjustment devices and channels.

[0041] Reference Figure 2 In some embodiments of the present invention, obtaining the slip degree comprises the following steps: S1.1, obtaining the initial wheel speed of the cycle, the expected deceleration of the cycle, the cycle period, the current wheel speed, the current vehicle speed and the wheel rolling radius; There are two cases when obtaining the expected cycle deceleration. The first case is that the multi-axle vehicle is in the first braking cycle, and the expected cycle deceleration is determined by the brake electronic control unit; the second case is that the multi-axle vehicle is not in the first braking cycle, and the initial wheel speed of the previous cycle, the end wheel speed of the previous cycle and the period of the previous cycle are obtained, and then the expected cycle deceleration is determined according to the initial wheel speed of the previous cycle, the end wheel speed of the previous cycle and the period of the previous cycle. In the case that the multi-axle vehicle is not in the first braking cycle, the expected cycle deceleration is determined by formula (1); (1) in, represents the expected wheel speed deceleration of wheel i; represents the initial wheel speed of wheel i in the previous cycle; represents the wheel speed of wheel i at the end of the previous cycle; Indicates the cycle period of the previous cycle.

[0042] S1.2, determining the nominal wheel speed according to the cycle initial wheel speed, the cycle expected deceleration, the cycle period, the current wheel speed, the current vehicle speed and the wheel rolling radius; wherein the nominal wheel speed is determined by formula (2); (2) in, Indicates the nominal wheel speed; Indicates the current wheel speed; Indicates the initial wheel speed of the cycle; t Indicates the cycle period; Indicates the current vehicle speed; Indicates the wheel rolling radius.

[0043] S1.3, determining the slip degree according to the nominal wheel speed and the current wheel speed. The slip degree is determined by formula (3); (3) in, Indicates the degree of slip.

[0044] Reference Figure 3 In some embodiments of the present invention, obtaining the wheel speed vector comprises the following steps: S1.4, obtaining the initial wheel speed vector of the wheel corresponding to the channel; S1.5. Obtain the initial wheel speed of the wheel corresponding to the channel; S1.6, Continuously Obtain Wheels k Current wheel speed; S1.7, through k The current wheel speed and the initial wheel speed determine the wheel speed vector. k The wheel speed vector is determined based on the current wheel speed and the initial wheel speed, including the following steps: pass k The current wheel speed and the initial wheel speed determine whether the wheel speed vector is downward. If the wheel speed vector is downward, the wheel speed vector is output; if the wheel speed vector is not downward, the wheel speed vector is output. k The current wheel speed and the initial wheel speed determine whether the wheel speed vector is upward. If the wheel speed vector is upward, the wheel speed vector is output. If the wheel speed vector is not upward, the output result of the previous step is output.

[0045] Among them, whether the wheel speed vector is downward is determined by formula (4); whether the wheel speed vector is upward is determined by formula (5); (4) (5) in, Indicates the first current wheel speed; Indicates the kth current wheel speed.

[0046] The present invention also provides an anti-lock control device for a multi-axle vehicle, comprising a braking system as described in any one of the above embodiments. The vehicle may be a three-axle vehicle with two rear axles, a three-axle vehicle with two front axles, or a four-axle vehicle with two front axles and two rear axles. The braking systems of the three types of vehicles all have four channels, namely, the left front axle, the right rear axle, and the left rear axle. fl Channel 12.1, front right fr Channel 12.2, left rear rl Channel 12.3 and right rear rr Channel 12.4: Each channel controls the braking of at least one wheel, and the number of wheels controlled by each channel depends on the type of vehicle.

[0047] The brake systems of the three vehicles all include a first hydraulic circuit 11.1 and a second hydraulic circuit 11.2, both of which are connected to the brake pedal 5. The first hydraulic circuit 11.1 is connected to a first energy storage device 4.1, and the second hydraulic circuit 11.2 is connected to a second energy storage device 4.2. The first hydraulic circuit 11.1 is also provided with a first brake pressure building module 6.1, and the second hydraulic circuit 11.2 is provided with a second brake pressure building module 6.2. Left front fl Channel 12.1 and right front fr Channel 12.2 is arranged in parallel on the left rear of the first brake pressure building module 6.1 rl Channel 12.3 and right rear rr The channel 12.4 is arranged in parallel with the second brake pressure building module 6.2.

[0048] Reference Figure 7 The double rear axle three-axle vehicle is provided with six wheels, namely, the first wheel 1.1, the second wheel 1.2, the third wheel 1.3, the fourth wheel 1.4, the fifth wheel 1.5 and the sixth wheel 1.6. Among them, the first wheel 1.1 is provided with a first gear ring 2.1 and a first wheel speed sensor 3.1; the second wheel 1.2 is provided with a second gear ring 2.2 and a second wheel speed sensor 3.2; the third wheel 1.3 is provided with a third gear ring 2.3 and a third wheel speed sensor 3.3; the fourth wheel 1.4 is provided with a fourth gear ring 2.4 and a fourth wheel speed sensor 3.4; the fifth wheel 1.5 is provided with a fifth gear ring 2.5 and a fifth wheel speed sensor 3.5; the sixth wheel 1.6 is provided with a sixth gear ring 2.6 and a sixth wheel speed sensor 3.6.

[0049] For dual rear axle three-axle vehicles, right front fr Channel 12.2 controls the braking of the first wheel 1.1; left front fl Channel 12.1 controls the braking of the second wheel 1.2; right rear rr Channel 12.4 synchronously controls the braking of the third wheel 1.3 and the fifth wheel 1.5; left rear rlChannel 12.3 synchronously controls the braking of fourth wheel 1.4 and sixth wheel 1.6.

[0050] right front fr The end of the channel 12.2 is provided with a first brake actuator 8.1, the right front fr The first ABS adjustment device 7.1 is arranged in the middle of the channel 12.2; fl The end of the channel 12.1 is provided with a second brake actuator 8.2, the left front fl The middle part of the channel 12.1 is provided with a second ABS adjustment device 7.2; rr The channel 12.4 has two parallel ends, each of which is provided with a first brake actuator 9.1 with parking brake and a third brake actuator 9.3 with parking brake. rr The third ABS adjustment device 7.3 is arranged in the middle of the channel 12.4; rl The channel 12.3 has two parallel ends, each of which is provided with a second brake actuator 9.2 with parking brake and a fourth brake actuator 9.4 with parking brake. rl A fourth ABS regulating device 7.4 is arranged in the middle of the channel 12.3.

[0051] Among them, the first brake pressure building module 6.1 and the second brake pressure building module 6.2 are both connected to the brake pedal 5 by signal; the first wheel speed sensor 3.1, the second wheel speed sensor 3.2, the third wheel speed sensor 3.3, the fourth wheel speed sensor 3.4, the fifth wheel speed sensor 3.5, the sixth wheel speed sensor 3.6, the first brake pressure building module 6.1, the second brake pressure building module 6.2, the first ABS regulating device 7.1, the second ABS regulating device 7.2, the third ABS regulating device 7.3 and the fourth ABS regulating device 7.4 are all connected to the control unit (ECU) 10 by signal.

[0052] Reference Figure 8 The dual front axle three-axle vehicle is also provided with six wheels, namely the first wheel 1.1, the second wheel 1.2, the third wheel 1.3, the fourth wheel 1.4, the fifth wheel 1.5 and the sixth wheel 1.6. Among them, the first wheel 1.1 is provided with a first gear ring 2.1 and a first wheel speed sensor 3.1; the second wheel 1.2 is provided with a second gear ring 2.2 and a second wheel speed sensor 3.2; the third wheel 1.3 is provided with a third gear ring 2.3 and a third wheel speed sensor 3.3; the fourth wheel 1.4 is provided with a fourth gear ring 2.4 and a fourth wheel speed sensor 3.4; the fifth wheel 1.5 is provided with a fifth gear ring 2.5 and a fifth wheel speed sensor 3.5; the sixth wheel 1.6 is provided with a sixth gear ring 2.6 and a sixth wheel speed sensor 3.6.

[0053] Compared with the double rear axle three-axle vehicle, the double front axle three-axle vehicle is different in that: the right frontfr The channel 12.2 has two ends connected in parallel, and the two ends are respectively provided with a first brake actuating device 8.1 and a third brake actuating device 8.3; fl The channel 12.1 has two ends connected in parallel, and the two ends are respectively provided with a second brake actuator 8.2 and a fourth brake actuator 8.4; rr The end of the channel 12.4 is provided with a first brake actuator 9.1 with parking brake; rl The end of the channel 12.3 is provided with a second brake actuator 9.2 with parking brake. The rest of the configuration can refer to the double rear axle three-axle vehicle, which will not be described in detail here.

[0054] Reference Fig. 9 The double front axle and double rear axle three-axle vehicle is provided with eight wheels, namely, the first wheel 1.1, the second wheel 1.2, the third wheel 1.3, the fourth wheel 1.4, the fifth wheel 1.5, the sixth wheel 1.6, the seventh wheel 1.7 and the eighth wheel 1.8. Among them, the first wheel 1.1 is provided with a first gear ring 2.1 and a first wheel speed sensor 3.1; the second wheel 1.2 is provided with a second gear ring 2.2 and a second wheel speed sensor 3.2; the third wheel 1.3 is provided with a third gear ring 2.3 and a third wheel speed sensor 3.3; the fourth wheel 1.4 is provided with a fourth gear ring 2.4 and a fourth wheel speed sensor 3.4; the fifth wheel 1.5 is provided with a fifth gear ring 2.5 and a fifth wheel speed sensor 3.5; the sixth wheel 1.6 is provided with a sixth gear ring 2.6 and a sixth wheel speed sensor 3.6; the seventh wheel 1.7 is provided with a seventh gear ring 2.7 and a seventh wheel speed sensor 3.7; the eighth wheel 1.8 is provided with an eighth gear ring 2.8 and an eighth wheel speed sensor 3.8.

[0055] Compared with the double rear axle three-axle vehicle, the double front axle and double rear axle three-axle vehicle are different in that: the right front fr The channel 12.2 has two ends connected in parallel, and the two ends are respectively provided with a first brake actuating device 8.1 and a third brake actuating device 8.3; fl The channel 12.1 has two parallel-connected ends, and the second brake actuator 8.2 and the fourth brake actuator 8.4 are respectively provided at the two ends. The remaining configurations can refer to the double rear axle three-axle vehicle, and will not be described in detail here.

[0056] A complete embodiment of the present invention is provided below.

[0057] Reference Figure 4 and Figure 7 ,by Figure 7 center left front fl Channel 12.1 and left rear rl Take channel 12.3 as an example. The calculation of slip degree includes the following steps: S11: Determine whether this braking cycle is the first time, if it is the first time, go to step S12, if not, go to step S19.

[0058] S12: Get the initial wheel speed of this braking cycle. Figure 7 left front fl Channel 12.1 is used to obtain the initial wheel speed of the second wheel 1.2 ,against Figure 7 Left rear rl Channel 12.3 is used to obtain the initial wheel speed of the fourth wheel 1.4 and the initial wheel speed of the sixth wheel 1.6 , proceed to step S13.

[0059] S13: Get the expected deceleration of this braking cycle , taking the second wheel 1.2 as an example, the expected deceleration of this braking cycle is obtained , proceed to step S14.

[0060] S14: Get the braking cycle t , proceed to step S15.

[0061] S15: Get the current wheel speed. Figure 7 left front fl Channel 12.1, for obtaining the current wheel speed of the second wheel 1.2 ,against Figure 7 Left rear rl Channel 12.3, for obtaining the current wheel speed of the fourth wheel 1.4 and the current wheel speed of the sixth wheel 1.6 , proceed to step S16.

[0062] S16: Get current vehicle speed And the set wheel rolling radius , proceed to step S17.

[0063] S17: Calculate the nominal wheel speed of the wheel, which is the maximum of the current wheel speed, the difference between the initial wheel speed of the braking cycle and the product of the expected deceleration of this braking cycle and the braking cycle, and the ratio of the current vehicle speed to the wheel rolling radius. After the nominal wheel speed is calculated, enter step S18; Taking the second wheel 1.2 as an example, the nominal wheel speed of the second wheel 1.2 is: .

[0064] S18: Calculate the slippage degree, which is the maximum value of the difference between the nominal wheel speed and the actual wheel speed of each wheel in the channel; Figure 7 left front flChannel 12.1, the slip degree is: ;against Figure 7 Left rear rl 12.3 channel, the slip degree is: .

[0065] Reference Figure 5 and Figure 7 ,by Figure 7 center left front fl Channel 12.1 and left rear rl Taking channel 12.3 as an example, obtaining the wheel speed vector includes the following steps: S23: Obtain the channel initial default wheel speed vector and proceed to step S24.

[0066] S24: Get the wheels of this braking cycle in the channel i The initial wheel speed for Figure 7 Left front fl Channel 12.1 is used to obtain the initial wheel speed of the second wheel 1.2 ,against Figure 7 Left rear rl Channel 12.3 is used to obtain the initial wheel speed of the fourth wheel 1.4 and the initial wheel speed of the sixth wheel 1.6 , proceed to step S25.

[0067] S25: Get continuous k Wheels i The wheel speed goes to step S26; wherein, k It can be obtained through calibration. Taking the second wheel 1.2 as an example, it is necessary to obtain: .

[0068] S26: Determine whether the wheel speed vector is downward. The determination method is to determine whether it is continuous. k Wheels i The wheel speeds of all wheels in the channel are less than the initial wheel speeds. If the wheel speeds of all wheels in the channel meet this condition, the process proceeds to step S29; otherwise, the process proceeds to step S27; Among them, for Figure 7 Left front fl Channel 12.1, the method for determining whether the wheel speed vector is downward is: ;against Figure 7 Left rear rl Channel 12.3, the method for determining whether the wheel speed vector is downward is: and .

[0069] S27: Determine whether the wheel speed vector is upward. The determination method is to determine whether it is continuous. k Wheels iThe wheel speeds of all wheels in the channel are greater than the initial wheel speeds. If the wheel speeds of all wheels in the channel meet this condition, the process proceeds to step S30; otherwise, the process proceeds to step S28; Among them, for Figure 7 Left front fl Channel 12.1, the method for determining whether the wheel speed vector is upward is: ;against Figure 7 Left rear rl Channel 12.3, the method for determining whether the wheel speed vector is upward is: and .

[0070] S28: The wheel speed vector maintains the initial default wheel speed vector unchanged.

[0071] S29: The wheel speed vector is downward, and the wheel speed vector is defined as 1. Figure 7 Left front fl Taking channel 12.1 as an example, the wheel speed vector is assigned as follows: .

[0072] S30: The wheel speed vector is upward, and the wheel speed vector is defined as 0. Figure 7 Left front fl Taking channel 12.1 as an example, the wheel speed vector is assigned as follows: .

[0073] Reference Figure 6 and Figure 7 ,by Figure 7 center left front fl Channel 12.1 and left rear rl Taking channel 12.3 as an example, the multi-axle vehicle anti-lock braking control method includes the following steps: S31: Determine whether the slippage degree is greater than a first preset slippage degree threshold, if so, proceed to step S34, otherwise, proceed to step S32; Figure 7 left front fl Taking channel 12.1 as an example, it is necessary to determine whether the following formula is valid: ;in, Indicates left front fl The degree of slip in channel 12.1, Indicates the first preset threshold value of the slip degree.

[0074] S32: Determine whether the slippage degree is greater than a second preset slippage degree threshold value, if so, proceed to step S33, otherwise, proceed to step S41; Figure 7 left front fl Taking channel 12.1 as an example, it is necessary to determine whether the following formula is valid: ;in, Indicates a second preset threshold value of the slip degree.

[0075] S33: Determine the wheels in the channel i Whether the wheel speed deceleration is less than the preset wheel speed deceleration threshold value, the preset wheel speed deceleration threshold value can be confirmed by calibration, if it is less than, proceed to step S34, otherwise, proceed to step S41; Figure 7 left front fl Taking channel 12.1 as an example, it is necessary to determine whether the following formula is valid: ;against Figure 7 Left rear rl Taking channel 12.3 as an example, it is necessary to determine whether the following formula is valid: ;in, Indicates the preset threshold value for wheel speed deceleration.

[0076] wheel i The wheel speed deceleration rate can be determined by the initial wheel speed of the cycle , wheel speed at the end and cycle t Get, wheel i The deceleration is the initial wheel speed of the cycle Wheel speed at the end The difference and cycle period t The ratio of, that is: Taking the second wheel 1.2 as an example, the wheel speed deceleration of the second wheel 1.2 is: .

[0077] S34: Determine that the current vehicle body state is a vehicle body instability risk state, and proceed to step S35; S35: Taking the second wheel 1.2 as an example, the second ABS adjustment device 7.2 enters the decompression mode, reduces the magnitude of the braking force to achieve the adjustment of the vehicle anti-lock braking, and enters step S36; S36: Taking the second wheel 1.2 as an example, assigning a mode of the second ABS regulating device 7.2. The current mode of the second ABS regulating device 7.2 is the decompression mode. Assigning a value of 1 to the mode of the second ABS regulating device 7.2, and entering step S37; S37: Determine whether the current wheel speed vector is upward and whether the wheel speed vector value is 0. If the wheel speed vector value is 0, proceed to step S38; otherwise, proceed to step S35. Figure 7 left front fl Taking channel 12.1 as an example, it is necessary to determine whether the following formula is valid: ; The potential conditions for this determination are: ,in, Indicates the ABS control device mode.

[0078] S38: Determine that the current vehicle body state is an instability risk recovery state, and proceed to step S39; S39: Taking the second wheel 1.2 as an example, the second ABS adjustment device 7.2 enters the pressure holding mode, stabilizes the brake pressure at the current adjustment value to achieve the adjustment of the vehicle anti-lock braking, and enters step S40; S40: Taking the second wheel 1.2 as an example, assigning a mode of the second ABS regulating device 7.2. Currently, the second ABS regulating device 7.2 is in the pressure-maintaining mode. The mode of the second ABS regulating device 7.2 is assigned a value of 2, and the process proceeds to step S44; S41: Determine that the current vehicle body state is stable, the channel has no locking risk and does not need to be controlled, and does not need to enter the ABS mode, and proceed to step S42; S42: Taking the second wheel 1.2 as an example, the second ABS adjustment device 7.2 does not intervene in the braking force adjustment, and the braking pressure is based on the pedal travel, and the process goes to step S43; S43: Taking the second wheel 1.2 as an example, assigning a mode of the second ABS regulating device 7.2. The current mode of the second ABS regulating device 7.2 is not to enter the ABS mode, assigning a value of 0 to the second ABS regulating device 7.2, and entering step S31; S44: Determine whether the current wheel speed vector is downward and whether the wheel speed vector value is 1. If the wheel speed vector value is 1, proceed to step S45; otherwise, proceed to step S39; by Figure 7 Left front fl Taking channel 12.1 as an example, we need to determine whether the following formula is valid: ; The potential conditions for this determination are: .

[0079] S45: Determine whether the slip degree is less than a third preset slip degree threshold, if so, proceed to step S46, otherwise proceed to step S39; by Figure 7 Left front fl Taking channel 12.1 as an example, the following formula needs to be determined: ; The potential conditions for this determination are: .in, Indicates a third preset threshold value of the slip degree.

[0080] S46: Determine that the current vehicle body state is a recovery braking limit state, and proceed to step S47; S47: Taking the second wheel 1.2 as an example, the second ABS adjustment device 7.2 enters the boost mode to increase the current brake pressure to find the limit state of vehicle braking and achieve the maximum braking force adjustment of the vehicle, and then enters step S48; S48: Taking the second wheel 1.2 as an example, assign the mode of the second ABS regulating device 7.2. The current mode of the second ABS regulating device 7.2 is the boost mode, and the mode of the second ABS regulating device 7.2 is assigned a value of 3.

[0081] It should be noted that the first preset threshold value of slip degree, the second preset threshold value of slip degree and the third preset threshold value of slip degree in this method are three preset threshold values ​​of slip degree, which can be obtained through calibration. In addition, the preset threshold value of deceleration can also be obtained through calibration. However, it should be emphasized that the above preset threshold value is not a fixed value, and can change according to factors such as vehicle speed, vehicle deceleration, ground adhesion coefficient, axle load, engine torque, vehicle speed ratio, etc. And the first preset threshold value of slip degree, the second preset threshold value of slip degree and the third preset threshold value of slip degree must meet the following conditions: ;in, Indicates a first slip degree preset threshold value; Indicates a second slip degree preset threshold value; Indicates the third slip level preset threshold.

[0082] In addition, the method has four working modes, namely: no need to enter the ABS adjustment mode, the ABS adjustment device enters the decompression mode, the ABS adjustment device enters the pressure holding mode, and the ABS adjustment device enters the boost mode. The switching of the four modes needs to be judged according to the first condition, the second condition, and the third condition.

[0083] Among them, the first condition is step S31, step S32 and step S33. If the first condition is met, it can be determined that the vehicle body state is at an instability risk state and needs to enter the ABS decompression mode. At this time, the ABS mode is assigned to 1. The formula of the first condition is expressed as: ,or, and ;in, Indicates xx The degree of slip in the channel.

[0084] The second condition is step S37. If the second condition is met, it can be determined that the vehicle body is in an instability risk recovery state and needs to enter the ABS pressure holding mode. At this time, the ABS mode is assigned to 2. The premise for entering the second condition is that the ABS mode is assigned to 1. The formula for the first condition is expressed as: and .

[0085] The third condition is step S44 and step S45. If the third condition is met, it can be determined that the vehicle body state is now in the recovery braking limit state, and the ABS boost mode needs to be entered. At this time, the ABS mode is assigned to 3. The premise for entering the third condition is that the ABS mode is assigned to 2. The formula of the first condition is expressed as: and and .

[0086] If none of the above three conditions are met, the vehicle body is judged to be in a stable state, there is no risk of channel locking, and there is no need to enter the ABS mode. At this time, the braking pressure is based on the pedal travel, and the ABS mode is assigned to 0.

[0087] It should be noted that the anti-lock control principle of a three-axle vehicle with dual front axles and a four-axle vehicle with dual front axles and dual rear axles is the same as that of the above embodiment. For details, please refer to the above embodiment and will not be repeated here.

[0088] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A multi-axle vehicle anti-lock braking control method, characterized in that: Applied to a multi-axle vehicle, the multi-axle vehicle includes a braking system having a plurality of channels, each of the channels controls the braking of at least one wheel, each of the channels is provided with an ABS adjustment device, and the multi-axle vehicle anti-lock control method includes: Acquiring driving state information of the wheel, the driving state information including slip degree, wheel speed deceleration and wheel speed vector; When the slip degree and the wheel speed deceleration satisfy a first condition, the ABS adjustment device enters a decompression mode and determines whether the wheel speed vector satisfies a second condition; wherein the first condition is that the slip degree is greater than a first preset slip degree threshold, or the slip degree is greater than a second preset slip degree threshold and the wheel speed deceleration is less than a preset deceleration threshold; the first preset slip degree threshold is greater than the second preset slip degree threshold; the second condition is that the wheel speed vector is upward; When the wheel speed vector satisfies the second condition, the ABS adjustment device enters the pressure holding mode and determines whether the slip degree and the wheel speed vector satisfy a third condition; wherein the third condition is that the wheel speed vector is downward and the slip degree is less than a third preset slip degree threshold; and the second preset slip degree threshold is greater than the third preset slip degree threshold; When the slip degree and the wheel speed vector satisfy the third condition, the ABS adjustment device enters a boost mode; Anti-lock control is performed on the multi-axle vehicle according to the pressure reduction mode, the pressure maintenance mode and the pressure increase mode.

2. The multi-axle vehicle anti-lock braking control method according to claim 1, characterized in that: Obtaining the slip degree includes: Obtain the initial wheel speed of the cycle, the expected deceleration of the cycle, the cycle period, the current wheel speed, the current vehicle speed and the wheel rolling radius; Determining a nominal wheel speed according to the cycle initial wheel speed, the cycle expected deceleration, the cycle period, the current wheel speed, the current vehicle speed and the wheel rolling radius; The slip degree is determined according to the nominal wheel speed and the current wheel speed.

3. The multi-axle vehicle anti-lock braking control method according to claim 2, characterized in that: The obtaining of the expected cyclic deceleration includes: In the case where the multi-axle vehicle is in the first braking cycle, determining the expected deceleration of the cycle by a brake electronic control unit; When the multi-axle vehicle is not in the first braking cycle, the initial wheel speed of the previous cycle, the ending wheel speed of the previous cycle and the period of the previous cycle are obtained, and the expected deceleration of the cycle is determined based on the initial wheel speed of the previous cycle, the ending wheel speed of the previous cycle and the period of the previous cycle.

4. The multi-axle vehicle anti-lock braking control method according to claim 3, characterized in that: When the multi-axle vehicle is not in the first braking cycle, the cycle expected deceleration is determined by formula (1); （1） in, represents the expected wheel speed deceleration of wheel i; represents the initial wheel speed of wheel i in the previous cycle; represents the wheel speed of wheel i at the end of the previous cycle; Indicates the cycle period of the previous cycle.

5. The multi-axle vehicle anti-lock braking control method according to claim 4, characterized in that: The nominal wheel speed is determined by formula (2); （2） in, Indicates the nominal wheel speed; Indicates the current wheel speed; Indicates the initial wheel speed of the cycle; t Indicates the cycle period; Indicates the current vehicle speed; Indicates the wheel rolling radius.

6. The multi-axle vehicle anti-lock braking control method according to claim 5, characterized in that: The slip degree is determined by formula (3); （3） in, Indicates the degree of slip.

7. The multi-axle vehicle anti-lock braking control method according to claim 1, characterized in that: Obtaining the wheel speed vector includes: Obtaining an initial wheel speed vector of the wheel corresponding to the channel; Obtaining the initial wheel speed of the wheel corresponding to the channel; Continuously obtaining the current wheel speeds of k wheels; pass k The wheel speed vector is determined by the current wheel speed and the initial wheel speed.

8. The multi-axle vehicle anti-lock braking control method according to claim 7, characterized in that: Said through k The current wheel speed and the initial wheel speed are used to determine a wheel speed vector, including: pass k determining whether the wheel speed vector is downward based on the current wheel speed and the initial wheel speed, and if the wheel speed vector is downward, determining that the wheel speed vector is downward; In the case where the wheel speed vector is not downward, k The current wheel speed and the initial wheel speed are used to determine whether the wheel speed vector is upward. If the wheel speed vector is upward, it is determined that the wheel speed vector is upward; otherwise, it is determined that the wheel speed vector is downward.

9. The multi-axle vehicle anti-lock braking control method and device according to claim 8, characterized in that: Determine whether the wheel speed vector is downward by formula (4); determine whether the wheel speed vector is upward by formula (5); （4） （5） in, Indicates the first current wheel speed; Indicates the kth current wheel speed.

10. A multi-axle vehicle anti-lock control device, characterized in that: Comprising a braking system as described in any one of claims 1-9.

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