Method, device and storage medium for determining road adhesion state

Abstract

The present invention discloses a method, device and storage medium for determining a road surface adhesion state, wherein the method part includes: obtaining the longitudinal acceleration of a vehicle during driving, and a function activation signal of a vehicle body electronic stability system; determining the driving state of the vehicle, and determining whether a function corresponding to the driving state in the vehicle body electronic stability system is in an activated state according to the function activation signal; if the function corresponding to the driving state in the vehicle body electronic stability system is in an activated state, determining the road surface adhesion state of the vehicle driving surface according to the longitudinal acceleration of the vehicle; in the present invention, the function activation signal and longitudinal acceleration of the vehicle body electronic stability system are combined to identify the road surface adhesion state of the vehicle driving surface, taking into account the influence of the intervention of the vehicle body electronic stability system, and when the corresponding function of the vehicle body electronic stability system is activated, the longitudinal acceleration is directly used to determine the road surface adhesion state, which can quickly and accurately identify the road surface adhesion state.

Description

Technical Field

[0001] The present invention relates to the field of vehicle technology, and in particular to a method, device and storage medium for determining road adhesion status. Background Art

[0002] In recent years, the electronic control systems of new energy vehicles have developed rapidly. In order to ensure the safe driving of vehicles within the limit state, it is necessary to improve the relevant control strategies of the electronic control systems. The vehicle's electronic control system generally controls the vehicle according to the vehicle's driving conditions and road adhesion conditions. Therefore, the road adhesion state of the vehicle's driving surface has become an important factor affecting vehicle driving safety.

[0003] In the prior art, the vehicle's posture parameters are generally collected during driving, and then compared with the vehicle posture parameters on a typical road surface to evaluate the road adhesion state of the vehicle. Since the vehicle posture parameters with practical value among the vehicle posture parameters will change rapidly according to changes in road conditions, the vehicle posture parameters can provide feedback on the road adhesion state to a certain extent, that is, the road adhesion state of the vehicle can be evaluated based on the changes in the vehicle posture parameters. However, in new energy vehicles, the vehicle posture parameters are affected not only by road conditions, but also by other factors. For example, the intervention of the electronic stability system (ESP) during driving will interfere with the vehicle posture parameters. Therefore, only using the vehicle posture parameters to evaluate the road adhesion state cannot accurately identify the road adhesion state. Summary of the Invention

[0004] The present invention provides a road adhesion state determination method, device and storage medium to solve the problem in the prior art that only vehicle posture parameters are used to evaluate the road adhesion state, but the road adhesion state cannot be accurately identified.

[0005] A method for determining a road surface adhesion state is provided, comprising:

[0006] Obtain the longitudinal acceleration of the vehicle during driving, as well as the function activation signal of the vehicle electronic stability system;

[0007] determining a driving state of the vehicle and determining, based on a function activation signal, whether a function corresponding to the driving state in the vehicle electronic stability system is in an activated state;

[0008] If the function corresponding to the driving state in the vehicle electronic stability system is activated, the road adhesion state of the vehicle's driving road is determined based on the vehicle's longitudinal acceleration.

[0009] Furthermore, when the vehicle is in a driving state and the traction control function in the vehicle electronic stability system is activated, determining the road adhesion state of the road surface on which the vehicle is traveling based on the longitudinal acceleration of the vehicle includes:

[0010] Determine if the traction control function is in stability control state;

[0011] If the traction control function is in the stable control state, the road adhesion state of the road surface on which the vehicle is traveling is determined based on the acceleration range in which the longitudinal acceleration of the vehicle is located.

[0012] Furthermore, determining the road adhesion state of the vehicle's driving road according to the acceleration range of the vehicle's longitudinal acceleration includes:

[0013] If the longitudinal acceleration is in the first acceleration range, determining that the road adhesion state is the first adhesion state;

[0014] If the longitudinal acceleration is in the second acceleration range, the road adhesion state is determined to be the second adhesion state, the second acceleration range is smaller than the first acceleration range, and the road adhesion force corresponding to the second adhesion state is smaller than the road adhesion force corresponding to the first adhesion state;

[0015] If the longitudinal acceleration is in the third acceleration range, the road adhesion state is determined to be the third adhesion state, the third acceleration range is smaller than the second acceleration range, and the road adhesion force corresponding to the third adhesion state is smaller than the road adhesion force corresponding to the second adhesion state.

[0016] Furthermore, when the vehicle is in a braking state and the anti-lock braking control function in the vehicle electronic stability system is activated, determining the road adhesion state of the road surface on which the vehicle is traveling based on the longitudinal acceleration of the vehicle includes:

[0017] If the longitudinal acceleration is in the fourth acceleration interval, determining that the road adhesion state is the first adhesion state;

[0018] If the longitudinal acceleration is in the fifth acceleration interval, it is determined that the road adhesion state is the second adhesion state, and the fifth acceleration interval is greater than the fourth acceleration interval;

[0019] If the longitudinal acceleration is in the sixth acceleration interval, it is determined that the road adhesion state is the third adhesion state, and the sixth acceleration interval is greater than the fifth acceleration interval.

[0020] Furthermore, when the vehicle is coasting and the coasting regenerative torque verification function in the vehicle electronic stability system is activated, the road adhesion state of the road surface on which the vehicle is traveling is determined based on the longitudinal acceleration of the vehicle, including:

[0021] If it is determined that the longitudinal acceleration is in the seventh acceleration interval, then the road adhesion state is determined to be the second adhesion state;

[0022] If it is determined that the longitudinal acceleration is in the eighth acceleration interval, the road adhesion state is determined to be the third adhesion state, and the eighth acceleration interval is greater than the seventh acceleration interval.

[0023] Furthermore, after determining the driving state of the vehicle and determining whether a function corresponding to the driving state in the vehicle electronic stability system is in an activated state based on the function activation signal, the method further includes:

[0024] If the function corresponding to the driving state in the vehicle electronic stability system is in an inactive state, the road adhesion state of the road surface on which the vehicle is driving is determined based on the wheel speed or longitudinal acceleration of the vehicle.

[0025] Furthermore, determining the road adhesion state of the vehicle based on the wheel speed or longitudinal acceleration of the vehicle includes:

[0026] When the vehicle is in driving mode and the traction control function in the electronic stability system is not activated, the vehicle's slip rate is determined based on the vehicle's wheel speed, and the road adhesion state is determined based on the slip rate;

[0027] When the vehicle is in braking mode and the anti-lock braking system (ABS) function is inactive, the road adhesion state is determined based on the vehicle's longitudinal acceleration and brake pedal depth.

[0028] When the vehicle is coasting and the coasting regenerative torque calibration function in the vehicle's electronic stability system is inactive, the vehicle's slip ratio is determined based on the vehicle's wheel speed, and the road adhesion state is determined based on the slip ratio.

[0029] Furthermore, the road adhesion state is determined based on the longitudinal acceleration of the vehicle and the accelerator pedal depth, including:

[0030] determining whether the accelerator pedal depth is greater than a preset depth threshold, and determining whether the longitudinal acceleration is less than a preset acceleration threshold;

[0031] If the accelerator pedal depth is greater than a preset depth threshold and the longitudinal acceleration is less than a preset acceleration threshold, it is determined that the road adhesion state of the vehicle driving road is the first adhesion state.

[0032] A device for determining a road surface adhesion state is provided, comprising:

[0033] An acquisition module is used to obtain the longitudinal acceleration of the vehicle during driving and the function activation signal of the vehicle body electronic stability system;

[0034] a first determining module, configured to determine a driving state of the vehicle and determine, based on a function activation signal, whether a function corresponding to the driving state in the vehicle body electronic stability system is in an activated state;

[0035] The second determining module is configured to determine the road adhesion state of the road on which the vehicle is traveling according to the longitudinal acceleration of the vehicle if a function corresponding to the driving state in the vehicle body electronic stability system is activated.

[0036] A road surface adhesion state determination device is provided, comprising a memory, a processor, and a computer program stored in the memory and executable on the processor. When the processor executes the computer program, the steps of the road surface adhesion state determination method are implemented.

[0037] A readable storage medium is provided, wherein the readable storage medium stores a computer program, and when the computer program is executed by a processor, the steps of the above-mentioned method for determining the road surface adhesion state are implemented.

[0038] In one solution provided by the above-mentioned method, device and storage medium for determining the road adhesion state, the longitudinal acceleration of the vehicle during driving and the function activation signal of the vehicle body electronic stability system are obtained, and then the driving state of the vehicle is determined, and whether the function corresponding to the driving state in the vehicle body electronic stability system is activated according to the function activation signal is determined. If the function corresponding to the driving state in the vehicle body electronic stability system is activated, the road adhesion state of the road surface on which the vehicle is driving is determined according to the longitudinal acceleration of the vehicle. In the present invention, when the vehicle is in different driving states, the function activation signal and longitudinal acceleration of the vehicle body electronic stability system are combined to identify the road adhesion state of the road surface on which the vehicle is driving, taking into account the influence of the intervention of the vehicle body electronic stability system. When the corresponding function of the vehicle body electronic stability system is activated, the longitudinal acceleration is directly used to determine the road adhesion state, which can quickly and accurately identify the road adhesion state. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following briefly introduces the drawings required for use in the description of the embodiments of the present invention. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative labor.

[0040] Figure 1 is a structural schematic diagram of a vehicle in one embodiment of the present invention;

[0041] Figure 2 is a flow chart of a method for determining road adhesion state in one embodiment of the present invention;

[0042] Figure 3is another flowchart of a method for determining road adhesion status according to an embodiment of the present invention;

[0043] Figure 4 is a schematic structural diagram of a device for determining road adhesion state in one embodiment of the present invention;

[0044] Figure 5 FIG. 2 is another structural diagram of a device for determining road adhesion state in one embodiment of the present invention. DETAILED DESCRIPTION

[0045] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. All other embodiments obtained by ordinary technicians in this field based on the embodiments of the present invention without making any creative efforts shall fall within the scope of protection of the present invention.

[0046] The method for determining the road adhesion state provided by the embodiment of the present invention can be applied in the following situations: Figure 1 The illustrated vehicle includes an electronic stability system (ESS) 101 and a road adhesion state determination device 102. The ESS 101 communicates with the road adhesion state determination device 102 via a CAN network. During vehicle travel, the road adhesion state determination device obtains the vehicle's longitudinal acceleration and a function activation signal from the ESS. The device then determines the vehicle's driving state and, based on the function activation signal, determines whether the ESS function corresponding to the driving state is active. If the ESS function corresponding to the driving state is active, the device determines the road adhesion state based on the vehicle's longitudinal acceleration. Under different vehicle driving states, the ESS function activation signal and longitudinal acceleration are combined to identify the road adhesion state. This takes into account the influence of the ESS intervention. When the corresponding ESS function is activated, the device directly uses longitudinal acceleration to determine the road adhesion state, enabling real-time, rapid, and accurate road adhesion state identification.

[0047] Among them, the road adhesion state determining device 102 can be the vehicle control unit (VCU) of the vehicle. The electronic stability system (ESP) and the VCU are important control units for realizing the driving function of the vehicle (new energy vehicle). During the driving process of the vehicle, when the ESP intervenes to assist vehicle control, the ESP will send the activation state (on state) of the corresponding function on the ESP to the VCU through the CAN network, so that the VCU can identify the road adhesion state of the vehicle's driving road based on the ESP function activation signal, wheel speed and longitudinal acceleration, and adjust the vehicle control strategy according to the road adhesion state, thereby ensuring the driving safety of the vehicle.

[0048] In this embodiment, the vehicle includes the vehicle body electronic stability system 101 and the road adhesion state determination device 102 for exemplary purposes only. In other embodiments, the vehicle also includes other devices, which will not be described in detail here.

[0049] In one embodiment, if Figure 2 As shown, a method for determining the road adhesion state is provided. The method is described by taking the application of the method in the vehicle controller VCU as an example, and includes the following steps:

[0050] S10: Acquire the longitudinal acceleration of the vehicle during driving and the function activation signal of the vehicle body electronic stability system.

[0051] During driving, the VCU continuously acquires vehicle data in real time for subsequent analysis of road adhesion. This data includes vehicle speed, longitudinal acceleration, wheel speed, accelerator pedal signal, brake pedal signal, and the activation signal of the electronic stability system.

[0052] The longitudinal acceleration can be measured by longitudinal acceleration sensors installed on the vehicle, and the wheel speed can be measured by wheel speed sensors installed on each wheel. The wheel speed sensors and longitudinal acceleration sensors can be sensors equipped with the ESP. During vehicle operation, the ESP transmits the output signals of these sensors to the VCU via the CAN network. When the ESP intervenes to assist in vehicle control, the ESP transmits the activation status (on status) of the corresponding ESP function to the VCU via the CAN network. The VCU then identifies the road adhesion state of the vehicle based on the ESP function activation signal, the vehicle's wheel speed, and the longitudinal acceleration. It should be noted that when the vehicle is accelerating, the longitudinal acceleration is positive; the faster the vehicle accelerates, the greater the longitudinal acceleration. When the vehicle is decelerating, the longitudinal acceleration is negative; the faster the vehicle decelerates, the smaller the longitudinal acceleration.

[0053] S20: Determine the driving state of the vehicle, and determine whether a function corresponding to the driving state in the vehicle body electronic stability system is in an activated state according to the function activation signal.

[0054] After acquiring the vehicle data, the VCU will determine the vehicle's driving status based on the acquired vehicle data, and determine whether the function corresponding to the driving status in the vehicle's electronic stability system is activated based on the function activation signal.

[0055] The vehicle's driving state is determined based on the accelerator pedal signal, brake pedal signal, and vehicle speed in the vehicle data. The vehicle's driving state includes a driving state, a braking state, and a coasting state.

[0056] In one embodiment, determining the driving state of a vehicle specifically includes the following steps:

[0057] (1): When the accelerator pedal signal is detected, it means that the driver has stepped on the accelerator to accelerate the vehicle. At this time, the vehicle is determined to be in the driving state;

[0058] (2): When a brake pedal signal is detected, it indicates that the driver has stepped on the brake pedal to brake the vehicle. In this case, the vehicle is determined to be in a braking state.

[0059] (3): When no accelerator pedal signal is detected and the vehicle has a speed (the speed value is greater than 0), it means that the driver has not braked or driven the vehicle. At this time, the vehicle's driving state is determined to be a coasting state.

[0060] After determining the driving state of the vehicle, it is determined whether the function corresponding to the driving state in the body electronic stability system is in an activated state according to the function activation signal, including: when the driving state of the vehicle is a driving state, the VCU determines whether the driving state control function in the body electronic stability system is in an activated state according to the function activation signal; when the driving state of the vehicle is a braking state, the VCU determines whether the braking state control function in the body electronic stability system is in an activated state according to the function activation signal; when the driving state of the vehicle is a coasting state, the VCU determines whether the coasting state control function in the body electronic stability system is in an activated state according to the function activation signal.

[0061] For example, the driving state control function within the electronic stability system (ESP) is the traction control function (TCS). When the vehicle is in the driving state, the VCU determines whether the TCS is active based on the TCS activation signal from the ESP. If the TCS activation signal is received, the TCS is determined to be active. The braking state control function within the ESP is the anti-lock braking system (ABS). When the vehicle is in the braking state, the VCU determines whether the ABS is active based on the ABS activation signal from the ESP. If the ABS activation signal is received, the ABS is determined to be active. The coasting state control function within the ESP is the coasting regenerative torque calibration function (RBS). When the vehicle is in the coasting state, the VCU determines whether the RBS is active based on the RBS activation signal from the ESP. If the RBS activation signal is received, the RBS is determined to be active.

[0062] When the vehicle is driving on a low-adhesion road surface or accelerating rapidly on a high-adhesion road surface, to prevent the vehicle's drive wheels from slipping and causing the risk of loss of control, the ESP's TCS will activate and intervene to reduce the vehicle's slip rate and make the vehicle move forward at a certain slip rate. That is, TCS intervention will change the vehicle's slip rate and other vehicle posture parameters. Therefore, when the vehicle is in the driving state, in order to avoid interference with the road adhesion state recognition caused by the TCS intervention in the ESP, it is necessary to clarify the activation state of the TCS so that different road adhesion state recognition strategies can be adopted subsequently based on the judgment results of the TCS activation state.

[0063] When a vehicle brakes on a low-adhesion road surface or performs emergency braking on a high-adhesion road surface, the ABS of ESP will intervene to prevent wheel lock, allowing the vehicle to move forward at a certain slip rate to ensure vehicle stability. That is, ABS intervention will change the vehicle's slip rate and other vehicle posture parameters. Therefore, when the vehicle is in the braking state, in order to avoid interference with the road adhesion state recognition caused by ABS intervention in ESP, it is necessary to clarify the activation state of ABS so that different road adhesion state recognition strategies can be adopted based on the ABS activation state judgment results.

[0064] When a vehicle is coasting, its drive motor outputs braking force to assist in deceleration, while also recovering kinetic energy to charge the battery. Therefore, coasting for new energy vehicles also constitutes a deceleration condition, posing a risk of wheel lock. To prevent wheel lock when coasting on low-adhesion surfaces, ESP's Rear Braking System (RBS) intervenes, controlling the vehicle's forward motion at a specific slip ratio. This RBS intervention also alters vehicle attitude parameters, such as the slip ratio. Therefore, to prevent interference with ESP's road adhesion status recognition caused by RBS intervention during braking, it's important to clearly identify the RBS's activation status. This allows for the subsequent use of different road adhesion recognition strategies based on the RBS activation status.

[0065] S30: If the function corresponding to the driving state in the vehicle body electronic stability system is activated, determine the road adhesion state of the road surface on which the vehicle is driving according to the longitudinal acceleration of the vehicle.

[0066] After determining the driving state of the vehicle and determining whether a function corresponding to the driving state in the vehicle electronic stability system is in an activated state based on a function activation signal, if the function corresponding to the driving state in the vehicle electronic stability system is in an activated state, the road adhesion state of the road surface on which the vehicle is traveling can be determined based on the longitudinal acceleration of the vehicle.

[0067] For example, when the vehicle is in a driving state, if the traction control function TCS in the ESP is activated, then when it is determined that the traction control function is in a stable control state, the road adhesion state is determined according to the acceleration range of the longitudinal acceleration; when the vehicle is in a braking state, if the anti-lock braking control function ABS in the ESP is activated, the road adhesion state is determined according to the acceleration range of the longitudinal acceleration; when the vehicle is in a coasting state, if the coasting recovery torque calibration function RBS in the ESP is activated, the road adhesion state is determined according to the acceleration range of the longitudinal acceleration.

[0068] When the vehicle is in motion and the TCS within ESP is activated, it indicates that the vehicle may be entering a low-grip road, posing a risk of skidding and loss of control. At this point, TCS will control the vehicle's slip rate to an optimal value by reducing driving and braking forces, ensuring that the vehicle fully utilizes the road's maximum adhesion for acceleration without skidding. With TCS intervention, the vehicle's acceleration is positively correlated with the road's maximum adhesion: greater acceleration results in greater maximum adhesion. Since the road's maximum adhesion is directly determined by its adhesion state, the road's adhesion state can be directly determined based on the vehicle's longitudinal acceleration.

[0069] When a vehicle is braking, if the ABS within ESP is activated, ABS will adjust the braking force to optimize the vehicle's slip rate, ensuring maximum wheel-to-ground adhesion and decelerating without locking the vehicle. The deceleration rate during braking depends on the road's adhesion, or the friction provided by the road surface. The greater the friction, the faster the vehicle decelerates, the smaller the longitudinal acceleration, and the greater the absolute value of the longitudinal acceleration. The friction provided by high-adhesion roads is much greater than that of low-adhesion roads. Therefore, the road adhesion state can be inferred based on the relationship between the vehicle's longitudinal acceleration and the road's maximum adhesion.

[0070] When the vehicle is in a coasting state, if the RBS in ESP is activated, similar to ABS, RBS will control the vehicle's slip rate at an optimal value, ensuring that the vehicle fully utilizes the maximum adhesion of the road to decelerate without locking. Therefore, the road adhesion state can be inferred based on the relationship between the vehicle's longitudinal acceleration and the maximum adhesion of the road.

[0071] The road adhesion state of the driving surface is determined based on the formation status, ESP function activation signal and longitudinal acceleration. The impact of ESP intervention on road adhesion state identification is fully considered, improving the accuracy of road adhesion state identification. When the function corresponding to each driving state in ESP is in the activated state, the road adhesion state is directly determined based on the real-time longitudinal acceleration, reducing the amount of calculation and improving the speed of identifying the road adhesion state of the driving surface.

[0072] In this embodiment, the vehicle's driving state is determined by acquiring the longitudinal acceleration of the vehicle during driving and a function activation signal from the electronic stability system (ESS). Based on the function activation signal, it is determined whether the function corresponding to the driving state in the ESS is activated. If the function corresponding to the driving state in the ESS is activated, the road adhesion state of the road surface on which the vehicle is traveling is determined based on the vehicle's longitudinal acceleration. When the vehicle is in different driving states, the road adhesion state of the road surface on which the vehicle is traveling is identified based on the function activation signal and longitudinal acceleration of the ESS. This takes into account the impact of the ESS intervention. When the corresponding function of the ESS is activated, the road adhesion state is directly determined using longitudinal acceleration, enabling real-time, rapid, and accurate identification of the road adhesion state.

[0073] In one embodiment, if Figure 3 As shown, after step S20, that is, after determining the driving state of the vehicle and determining whether the function corresponding to the driving state in the vehicle body electronic stability system is in an activated state according to the function activation signal, the method further includes the following steps:

[0074] S40: If the function corresponding to the driving state in the vehicle electronic stability system is in an inactive state, determining the road adhesion state of the road on which the vehicle is driving based on the wheel speed or longitudinal acceleration of the vehicle.

[0075] After determining the vehicle's driving state and, based on the function activation signal, determining whether the corresponding function in the electronic stability system is active, if the corresponding function in the electronic stability system is inactive, the system can determine the road adhesion state based on the vehicle's wheel speed or longitudinal acceleration, allowing for timely adjustment of vehicle control strategies to ensure driving safety. When the corresponding function in the electronic stability system is inactive, the system directly uses a small number of vehicle posture parameters to determine the road adhesion state. This is faster than traditional methods that use multiple vehicle posture parameters to identify the road adhesion state. It also allows for timely adjustment of vehicle control strategies in the event of sudden changes in the road adhesion state, ensuring driving safety.

[0076] In this embodiment, after determining the driving state of the vehicle and determining whether the function corresponding to the driving state in the vehicle body electronic stability system is in an activated state based on the function activation signal, the road adhesion state of the road surface on which the vehicle is driving is determined based on the vehicle's wheel speed or longitudinal acceleration, which can improve the recognition speed of the road adhesion state.

[0077] In one embodiment, when the vehicle is in a driving state and the traction control function of the vehicle electronic stability system is activated, step S30, i.e., determining the road adhesion state of the vehicle based on the longitudinal acceleration of the vehicle, specifically includes the following steps:

[0078] SA31: Determine whether the traction control function is in the stable control state.

[0079] SA32: If the traction control function is in the stable control state, the road adhesion state of the road surface on which the vehicle is traveling is determined based on the acceleration range in which the longitudinal acceleration of the vehicle is located.

[0080] The TCS function generally activates only when the slip ratio exceeds a certain threshold. For front-wheel drive vehicles, during the initial activation phase of TCS, the speed of the driven wheels is significantly higher than that of the non-driven wheels. During this phase, the vehicle is slipping and not fully utilizing the road's maximum adhesion for acceleration. This indicates that the TCS is in an unstable control state. Once the TCS enters a stable control state, the vehicle fully utilizes the road's maximum adhesion for acceleration. At this point, longitudinal acceleration is positively correlated with the road's maximum adhesion. Therefore, when the vehicle is in a driving state and the traction control function in the electronic stability system is activated, it is necessary to determine whether the traction control function is in a stable control state. Only when the traction control function is in a stable control state can the road adhesion state be determined based on the vehicle's longitudinal acceleration range. This can mitigate the effects of slip during the initial TCS activation phase and improve the accuracy of road adhesion state identification. In the driving state, the acceleration ranges corresponding to different road adhesion states are determined by actual vehicle calibration. The lower the maximum adhesion provided by the road surface and the smaller the road's adhesion coefficient, the smaller the corresponding acceleration range.

[0081] Determining that the traction control function is in a stable state includes: determining the slip rate of the vehicle and determining a slip rate stability range corresponding to the vehicle, wherein the slip rate stability range is a slip rate range calibrated according to the actual operating conditions of the vehicle; determining whether the slip rate of the vehicle is in the slip rate stability range; if the slip rate of the vehicle is in the slip rate stability range, determining that the traction control function is in a stable state.

[0082] In this embodiment, when the vehicle is in a driving state and the traction control function of the vehicle electronic stability system is activated, it is necessary to first determine whether the traction control function is in a stable control state. If the traction control function is in a stable control state, the road adhesion state of the road surface on which the vehicle is traveling is determined based on the acceleration range within which the vehicle's longitudinal acceleration is located. After ensuring that the traction control function is in a stable control state, the road adhesion state of the road surface on which the vehicle is traveling is determined again based on the acceleration range within which the vehicle's longitudinal acceleration is located, thereby further improving the accuracy of road adhesion state identification.

[0083] In one embodiment, step SA32, i.e., determining the road adhesion state of the vehicle based on the acceleration interval of the vehicle's longitudinal acceleration, specifically includes the following steps:

[0084] SA321: If the longitudinal acceleration is in the first acceleration range, determine that the road adhesion state is the first adhesion state.

[0085] SA322: If the longitudinal acceleration is in the second acceleration range, determine that the road adhesion state is the second adhesion state.

[0086] SA323: If the longitudinal acceleration is in the third acceleration range, determine that the road adhesion state is the third adhesion state.

[0087] In this embodiment, the first, second, and third acceleration intervals are vehicle longitudinal acceleration intervals corresponding to different road adhesion states during driving, and are calibrated based on the vehicle's acceleration performance during driving. The first, second, and third acceleration intervals can be determined by conducting driving tests on road surfaces with varying adhesion levels to obtain driving longitudinal acceleration data. This data represents the longitudinal acceleration of the vehicle while driving on road surfaces with varying adhesion levels. Based on this driving longitudinal acceleration data, three acceleration intervals are then determined for direct use in subsequent identification of road adhesion states.

[0088] When the vehicle is in driving state and the traction control function TCS in the electronic stability system is activated, if the traction control function is in stable control state, it means that the vehicle fully utilizes the maximum adhesion of the road surface for acceleration. At this time, the longitudinal acceleration is positively correlated with the maximum adhesion of the road surface. The road adhesion state can be directly determined based on the acceleration range of the vehicle's longitudinal acceleration.

[0089] When the vehicle is in the driving state and the traction control function TCS of the electronic stability system is activated, if the longitudinal acceleration is in a first acceleration range, the road adhesion state is determined to be the first adhesion state; if the longitudinal acceleration is in a second acceleration range, the road adhesion state is determined to be the second adhesion state, wherein the second acceleration range is smaller than the first acceleration range, and the road adhesion force corresponding to the second adhesion state is smaller than the road adhesion force corresponding to the first adhesion state; if the longitudinal acceleration is in a third acceleration range, the road adhesion state is determined to be the third adhesion state, wherein the third acceleration range is smaller than the second acceleration range, and the road adhesion force corresponding to the third adhesion state is smaller than the road adhesion force corresponding to the second adhesion state.

[0090] For example, the first acceleration interval is the acceleration interval for the vehicle to be driven on a high-adhesion road surface; the second acceleration interval is the acceleration interval for the vehicle to be driven on a snowy surface; and the third acceleration interval is the acceleration interval for the vehicle to be driven on an icy surface. When the vehicle is in the driving state and the traction control function in the vehicle body electronic stability system is activated, if the vehicle's longitudinal acceleration is in the first acceleration interval, the road adhesion state is determined to be the first adhesion state, indicating that the vehicle is traveling on a high-adhesion road surface; if the vehicle's longitudinal acceleration is in the second acceleration interval, the road adhesion state is determined to be the second adhesion state, indicating that the vehicle is traveling on a snowy surface; if the vehicle's longitudinal acceleration is in the third acceleration interval, the road adhesion state is determined to be the third adhesion state, indicating that the vehicle is traveling on an icy surface.

[0091] In this embodiment, the acceleration range in the driving state is divided into three acceleration ranges for exemplary purposes only. In other embodiments, the acceleration range in the driving state may be divided into more acceleration ranges based on the actual accuracy requirements of the control strategy to improve the accuracy of road adhesion state recognition and thereby improve vehicle driving safety.

[0092] In this embodiment, when the vehicle is in a driving state and the traction control function of the vehicle electronic stability system is activated, if the longitudinal acceleration is in a first acceleration range, the road adhesion state is determined to be the first adhesion state. If the longitudinal acceleration is in a second acceleration range, the road adhesion state is determined to be the second adhesion state. The second acceleration range is smaller than the first acceleration range, and the road adhesion corresponding to the second adhesion state is smaller than the road adhesion corresponding to the first adhesion state. If the longitudinal acceleration is in a third acceleration range, the road adhesion state is determined to be the third adhesion state. The third acceleration range is smaller than the second acceleration range, and the road adhesion corresponding to the third adhesion state is smaller than the road adhesion corresponding to the second adhesion state. The specific steps for determining the road adhesion state of the road surface on which the vehicle is traveling based on the acceleration range in which the vehicle's longitudinal acceleration is located are refined. The acceleration range corresponding to the driving state is divided into three. When the vehicle is in a driving state, the TCS is activated, and is in a stability control state, the road adhesion state of the current road surface can be determined by directly determining the range in which the longitudinal acceleration is located. This further improves the speed of road adhesion state identification while meeting safety control requirements.

[0093] In one embodiment, when the vehicle is in a braking state and the anti-lock braking control function of the vehicle electronic stability system is activated, step S30, i.e., determining the road adhesion state of the road surface on which the vehicle is traveling based on the longitudinal acceleration of the vehicle, specifically includes the following steps:

[0094] SB31: If the longitudinal acceleration is in the fourth acceleration range, determining that the road adhesion state is the first adhesion state;

[0095] SB32: If the longitudinal acceleration is in the fifth acceleration range, determine that the road adhesion state is the second adhesion state;

[0096] SB33: If the longitudinal acceleration is in the sixth acceleration range, determine that the road adhesion state is the third adhesion state.

[0097] In this embodiment, the fourth, fifth, and sixth acceleration intervals are vehicle longitudinal acceleration intervals corresponding to different road adhesion states during braking, and are calibrated based on the vehicle's acceleration performance during braking. The fourth, fifth, and sixth acceleration intervals can be determined by conducting a braking driving test on road surfaces with varying adhesion levels to obtain braking longitudinal acceleration data. This data represents the longitudinal acceleration of the vehicle under braking on road surfaces with varying adhesion levels. Three acceleration intervals are then determined based on this braking longitudinal acceleration data for subsequent use in identifying road adhesion states. The accelerations in the fourth, fifth, and sixth acceleration intervals are negative, the fifth acceleration interval is greater than the fourth acceleration interval, and the sixth acceleration interval is greater than the fifth acceleration interval. Specifically, the absolute value of the acceleration in the fifth acceleration interval is greater than that in the fourth acceleration interval, and the absolute value of the acceleration in the sixth acceleration interval is greater than that in the fifth acceleration interval.

[0098] When the vehicle is in braking state and the anti-lock braking system (ABS) is activated, it means that the vehicle fully utilizes the maximum adhesion of the road to decelerate. At this time, the longitudinal acceleration is negatively correlated with the maximum adhesion of the road. The road adhesion state can be directly determined based on the acceleration range of the vehicle's longitudinal acceleration.

[0099] When the vehicle is in a braking state and the anti-lock braking system (ABS) is activated, if the longitudinal acceleration is in the fourth acceleration range, the road adhesion state is determined to be the first adhesion state; if the longitudinal acceleration is in the fifth acceleration range, the road adhesion state is determined to be the second adhesion state; and if the longitudinal acceleration is in the sixth acceleration range, the road adhesion state is determined to be the third adhesion state.

[0100] For example, the fourth acceleration interval is the acceleration interval for braking a vehicle on a high-adhesion road surface; the fifth acceleration interval is the acceleration interval for braking a vehicle on a snowy surface; and the sixth acceleration interval is the acceleration interval for braking a vehicle on an icy surface. When the vehicle is in a braking state and the ABS in the vehicle electronic stability system is activated, if the vehicle's longitudinal acceleration is in the fourth acceleration interval, the road adhesion state is determined to be the first adhesion state, indicating that the vehicle is traveling on a high-adhesion road surface; if the vehicle's longitudinal acceleration is in the fifth acceleration interval, the road adhesion state is determined to be the second adhesion state, indicating that the vehicle is traveling on a snowy surface; and if the vehicle's longitudinal acceleration is in the sixth acceleration interval, the road adhesion state is determined to be the third adhesion state, indicating that the vehicle is traveling on an icy surface.

[0101] In this embodiment, the acceleration interval in the braking state is divided into three acceleration intervals for exemplary purposes only. In other embodiments, the acceleration interval in the braking state may be divided into more acceleration intervals based on the actual accuracy requirements of the control strategy to improve the accuracy of road adhesion state recognition and thereby improve vehicle driving safety.

[0102] In this embodiment, when the vehicle is in a braking state and the anti-lock braking control function of the vehicle electronic stability system is activated, if the longitudinal acceleration is in the fourth acceleration range, the road adhesion state is determined to be the first adhesion state; if the longitudinal acceleration is in the fifth acceleration range, the road adhesion state is determined to be the second adhesion state, and the fifth acceleration range is greater than the fourth acceleration range; if the longitudinal acceleration is in the sixth acceleration range, the road adhesion state is determined to be the third adhesion state, and the sixth acceleration range is greater than the fifth acceleration range. The acceleration range corresponding to the braking state is divided into three. When the vehicle is in a braking state and the ABS is activated, the road adhesion state of the current driving road surface can be determined by directly determining the range in which the longitudinal acceleration is located. This further improves the speed of road adhesion state identification while meeting safety control requirements.

[0103] In one embodiment, when the vehicle is coasting and the coasting regenerative torque calibration function of the vehicle electronic stability system is activated, step S30, i.e., determining the road adhesion state of the vehicle based on the longitudinal acceleration of the vehicle, specifically includes the following steps:

[0104] SC31: If it is determined that the longitudinal acceleration is in the seventh acceleration range, determine that the road surface adhesion state is the second adhesion state.

[0105] SC32: If it is determined that the longitudinal acceleration is in the eighth acceleration interval, then the road adhesion state is determined to be the third adhesion state, and the eighth acceleration interval is greater than the seventh acceleration interval.

[0106] In this embodiment, the seventh and eighth acceleration intervals are longitudinal acceleration intervals corresponding to different road adhesion states when the vehicle is in a coasting state. They are calibrated based on the vehicle's acceleration performance in the coasting state. Since the coasting regenerative torque calibration function (RBS) can only be activated on low-adhesion roads, only two longitudinal acceleration intervals corresponding to low-adhesion roads need to be set during RBS. The seventh and eighth acceleration intervals can be determined by conducting coasting state driving tests on roads with different adhesion levels to obtain longitudinal acceleration data for the vehicle in the coasting state. This data represents the longitudinal acceleration of the vehicle in the coasting state on roads with different adhesion levels. Based on this longitudinal acceleration data, two acceleration intervals are determined for direct use in subsequent road adhesion state identification. The accelerations in the seventh and eighth acceleration intervals are negative, and the eighth acceleration interval is greater than the seventh acceleration interval, i.e., the absolute value of the acceleration in the seventh acceleration interval is greater than that in the eighth acceleration interval.

[0107] When the vehicle is in a coasting state and the RBS in the electronic stability system is activated, it means that the vehicle fully utilizes the maximum adhesion of the road to decelerate. At this time, the longitudinal acceleration is negatively correlated with the maximum adhesion of the road. The road adhesion state can be directly determined based on the acceleration range of the vehicle's longitudinal acceleration.

[0108] When the vehicle is coasting and the RBS in the electronic stability system is activated, if the longitudinal acceleration is in the seventh acceleration range, the road adhesion state is determined to be the second adhesion state; if the longitudinal acceleration is in the eighth acceleration range, the road adhesion state is determined to be the third adhesion state.

[0109] For example, the seventh acceleration interval is the acceleration interval for the vehicle sliding on snow; the eighth acceleration interval is the acceleration interval for the vehicle sliding on ice. When the vehicle is sliding and the RBS in the electronic stability system is activated, if the vehicle's longitudinal acceleration is in the seventh acceleration interval, the road adhesion state is determined to be the second adhesion state, indicating that the vehicle is driving on a snowy surface. If the vehicle's longitudinal acceleration is in the eighth acceleration interval, the road adhesion state is determined to be the third adhesion state, indicating that the vehicle is driving on an icy surface.

[0110] In this embodiment, the acceleration interval in the coasting state is divided into two acceleration intervals for exemplary purposes only. In other embodiments, the acceleration interval in the coasting state may be divided into more acceleration intervals based on the actual accuracy requirements of the control strategy to improve the accuracy of road adhesion state recognition and thereby improve vehicle driving safety.

[0111] In this embodiment, when the vehicle is coasting and the coasting regenerative torque verification function of the vehicle electronic stability system is activated, if the longitudinal acceleration is determined to be in the seventh acceleration range, the road adhesion state is determined to be the second adhesion state; if the longitudinal acceleration is determined to be in the eighth acceleration range, the road adhesion state is determined to be the third adhesion state. The eighth acceleration range is greater than the seventh acceleration range. When the vehicle is coasting and the ABS is activated, the road adhesion state of the current driving road surface can be determined by directly determining the range in which the longitudinal acceleration is located. This further improves the speed of road adhesion state identification while meeting safety control requirements.

[0112] In one embodiment, step S40, i.e., determining the road adhesion state of the vehicle based on the wheel speed or longitudinal acceleration of the vehicle, specifically includes the following steps:

[0113] S41: When the vehicle is in a driving state and the traction control function in the vehicle electronic stability system is in an inactive state, the vehicle slip rate is determined according to the wheel speed of the vehicle, and the road adhesion state is determined according to the slip rate.

[0114] Generally speaking, the traction control function (TCS) is not activated on high-adhesion surfaces except under rapid acceleration. Therefore, when the vehicle is braking, the VCU only needs to confirm that the current slip rate is within the normal driving range to determine that the vehicle is not slipping and that the road surface provides sufficient adhesion. Therefore, when the vehicle is in the driving state and the TCS in the ESP is inactive, it means that ESP is not intervening in vehicle control. At this time, ESP cannot affect the road adhesion state. Instead, it can determine the vehicle's slip rate based on the vehicle's wheel speed, and then determine the road adhesion state based on the slip rate.

[0115] The vehicle's slip rate is calculated using the following formula:

[0116] r r t =(u max -u ref ) / u max ;

[0117] Among them, r rot is the slip rate, u max is the maximum wheel speed among multiple wheel speeds, u ref is the pre-calculated reference speed.

[0118] After determining the vehicle's slip rate based on the wheel speed, determining the road adhesion state based on the slip rate includes determining whether the vehicle's slip rate is less than a preset slip rate. If the vehicle's slip rate is less than the preset slip rate, the road adhesion state is determined to be the first adhesion state. The preset slip rate is a slip rate threshold for driving on a high-adhesion road surface. If the slip rate continues to increase to a certain activation threshold, the TCS in the ESP is activated. The road adhesion state identification process after TCS activation is as described above and will not be further elaborated here.

[0119] S42: When the vehicle is in a braking state and the anti-lock control function in the vehicle electronic stability system is in an inactive state, the road adhesion state is determined based on the longitudinal acceleration of the vehicle and the brake pedal depth.

[0120] When the vehicle is braking, the magnitude of the braking deceleration is directly dependent on the road's adhesion and the braking torque. Therefore, the VCU determines whether it is on a high-adhesion road surface based on the magnitude of the deceleration when the brakes are applied. When the vehicle is in driving mode and the ABS in the ESP is not activated, ESP is not involved in vehicle control. At this time, ESP cannot affect the road's adhesion. The road's adhesion can be determined based on the vehicle's longitudinal acceleration and brake pedal depth.

[0121] S43: When the vehicle is in a coasting state and the coasting recovery torque calibration function in the vehicle body electronic stability system is in an inactive state, the vehicle slip ratio is determined according to the wheel speed of the vehicle, and the road adhesion state is determined according to the slip ratio.

[0122] When the vehicle is in a coasting state and the coasting recovery torque calibration function RBS in ESP is in an inactive state, it means that ESP has not intervened in vehicle control. At this time, ESP cannot affect the road adhesion state. The VCU can determine whether the wheel is unstable based on the vehicle's current slip rate, that is, it can determine the vehicle's slip rate based on the vehicle's wheel speed, and determine the road adhesion state based on the slip rate.

[0123] The vehicle's slip rate is calculated using the following formula:

[0124] r slip =(u min -u ref ) / u ref ;

[0125] Among them, r slip is the slip rate, u min is the minimum wheel speed among multiple wheel speeds, u ref is the pre-calculated reference speed.

[0126] After determining the vehicle's slip ratio based on the wheel speed, determining the road adhesion state based on the slip ratio includes determining whether the vehicle's slip ratio is less than a preset slip ratio. If the vehicle's slip ratio is less than the preset slip ratio, the road adhesion state is determined to be the first adhesion state. The preset slip ratio is a slip ratio threshold for when the vehicle is traveling on a high-adhesion road surface. If the slip ratio continues to increase to a certain activation threshold, the Rear Braking System (RBS) in the ESP is activated. The road adhesion state identification process after RBS activation is as described above and will not be further elaborated here.

[0127] In this embodiment, when the vehicle is in a driving state and the traction control function of the electronic stability system is inactive, the vehicle's slip ratio is determined based on the vehicle's wheel speed, and the road adhesion state is determined based on the slip ratio. When the vehicle is in a braking state and the anti-lock braking control function of the electronic stability system is inactive, the road adhesion state is determined based on the vehicle's longitudinal acceleration and brake pedal depth. When the vehicle is in a coasting state and the coasting regenerative torque verification function of the electronic stability system is inactive, the vehicle's slip ratio is determined based on the vehicle's wheel speed, and the road adhesion state is determined based on the slip ratio. The step of determining the road adhesion state of the road surface on which the vehicle is traveling based on the vehicle's wheel speed or longitudinal acceleration has been refined. Different vehicle posture parameters are used to identify the road adhesion state in different driving states, thereby reducing the amount of computation while ensuring correct identification of the road adhesion state.

[0128] In one embodiment, step S42, i.e., determining the road adhesion state of the vehicle based on the wheel speed or longitudinal acceleration of the vehicle, specifically includes the following steps:

[0129] S421: Determine whether the brake pedal depth is greater than a preset depth threshold, and determine whether the longitudinal acceleration is less than a preset acceleration threshold.

[0130] S422: If the brake pedal depth is greater than the preset depth threshold and the longitudinal acceleration is less than the preset acceleration threshold, determine that the road adhesion state of the vehicle driving on the road is the first adhesion state.

[0131] When the vehicle is in a braking state and the anti-lock braking control function in the vehicle electronic stability system is in an inactive state, the brake pedal depth is determined based on the brake pedal signal in the vehicle data, and the longitudinal acceleration of the vehicle is determined. Then, it is determined whether the brake pedal depth is greater than a preset depth threshold, and whether the longitudinal acceleration is less than a preset acceleration threshold. If the brake pedal depth is greater than the preset depth threshold and the longitudinal acceleration is less than the preset acceleration threshold, it indicates that the vehicle's braking force is large and the absolute value of the vehicle's longitudinal acceleration is large. At this time, the friction force provided by the driving road surface is large, and the road adhesion state of the vehicle's driving road surface is determined to be the first adhesion state, that is, the vehicle's driving road surface is a high-adhesion road surface.

[0132] In this embodiment, by determining whether the brake pedal depth is greater than a preset depth threshold and whether the longitudinal acceleration is less than a preset acceleration threshold, if the brake pedal depth is greater than the preset depth threshold and the longitudinal acceleration is less than the preset acceleration threshold, the road adhesion state of the road surface on which the vehicle is traveling is determined to be the first adhesion state. This embodiment clarifies the specific steps for determining the road adhesion state based on the vehicle's longitudinal acceleration and accelerator pedal depth. When the vehicle is in the braking state, the road adhesion state is identified by simultaneously combining the vehicle's longitudinal acceleration and brake pedal depth, thereby improving the accuracy of road adhesion state identification.

[0133] It should be understood that the size of the serial numbers of the steps in the above embodiments does not mean the order of execution. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of the present invention.

[0134] In one embodiment, a road surface adhesion state determination device is provided, which corresponds one-to-one to the road surface adhesion state determination method in the above embodiment. Figure 4 As shown, the road adhesion state determination device includes an acquisition module 401, a first determination module 402, and a second determination module 403. The functional modules are described in detail as follows:

[0135] An acquisition module 401 is used to acquire the longitudinal acceleration of the vehicle during driving and a function activation signal of the vehicle body electronic stability system;

[0136] A first determining module 402 is configured to determine a driving state of the vehicle and determine whether a function corresponding to the driving state in the vehicle electronic stability system is activated according to the function activation signal;

[0137] The second determining module 403 is configured to determine the road adhesion state of the vehicle according to the longitudinal acceleration of the vehicle if the function corresponding to the driving state in the vehicle body electronic stability system is activated.

[0138] Furthermore, when the vehicle is in a driving state and the traction control function in the vehicle body electronic stability system is activated, the second determining module 403 is specifically configured to:

[0139] Determine if the traction control function is in stability control state;

[0140] If the traction control function is in the stable control state, the road adhesion state of the road surface on which the vehicle is traveling is determined based on the acceleration range in which the longitudinal acceleration of the vehicle is located.

[0141] Furthermore, the second determining module 403 is further configured to:

[0142] If the longitudinal acceleration is in the first acceleration range, determining that the road adhesion state is the first adhesion state;

[0143] If the longitudinal acceleration is in the second acceleration range, the road adhesion state is determined to be the second adhesion state, the second acceleration range is smaller than the first acceleration range, and the road adhesion force corresponding to the second adhesion state is smaller than the road adhesion force corresponding to the first adhesion state;

[0144] If the longitudinal acceleration is in the third acceleration range, the road adhesion state is determined to be the third adhesion state, the third acceleration range is smaller than the second acceleration range, and the road adhesion force corresponding to the third adhesion state is smaller than the road adhesion force corresponding to the second adhesion state.

[0145] Furthermore, when the driving state of the vehicle is a braking state and the anti-lock braking control function in the vehicle body electronic stability system is in an activated state, the second determining module 403 is further configured to:

[0146] If the longitudinal acceleration is in the fourth acceleration interval, determining that the road adhesion state is the first adhesion state;

[0147] If the longitudinal acceleration is in the fifth acceleration interval, it is determined that the road adhesion state is the second adhesion state, and the fifth acceleration interval is greater than the fourth acceleration interval;

[0148] If the longitudinal acceleration is in the sixth acceleration interval, it is determined that the road adhesion state is the third adhesion state, and the sixth acceleration interval is greater than the fifth acceleration interval.

[0149] Furthermore, when the vehicle is in a coasting state and the coasting recovery torque verification function in the vehicle body electronic stability system is activated, the second determining module 403 is further configured to:

[0150] If it is determined that the longitudinal acceleration is in the seventh acceleration interval, then the road adhesion state is determined to be the second adhesion state;

[0151] If it is determined that the longitudinal acceleration is in the eighth acceleration interval, the road adhesion state is determined to be the third adhesion state, and the eighth acceleration interval is greater than the seventh acceleration interval.

[0152] Furthermore, the road adhesion state determination device further includes a third determination module 404. After determining the driving state of the vehicle and determining whether the function corresponding to the driving state in the vehicle electronic stability system is activated based on the function activation signal, the third determination module 404 is specifically configured to:

[0153] If the function corresponding to the driving state in the vehicle electronic stability system is in an inactive state, the road adhesion state of the road surface on which the vehicle is driving is determined based on the wheel speed or longitudinal acceleration of the vehicle.

[0154] Furthermore, the third determining module 404 is specifically configured to:

[0155] When the vehicle is in driving mode and the traction control function in the electronic stability system is not activated, the vehicle's slip rate is determined based on the vehicle's wheel speed, and the road adhesion state is determined based on the slip rate;

[0156] When the vehicle is in braking mode and the anti-lock braking system (ABS) function is inactive, the road adhesion state is determined based on the vehicle's longitudinal acceleration and brake pedal depth.

[0157] When the vehicle is coasting and the coasting regenerative torque calibration function in the vehicle's electronic stability system is inactive, the vehicle's slip ratio is determined based on the vehicle's wheel speed, and the road adhesion state is determined based on the slip ratio.

[0158] Furthermore, the third determining module 404 is further configured to:

[0159] determining whether a brake pedal depth is greater than a preset depth threshold, and determining whether a longitudinal acceleration is less than a preset acceleration threshold;

[0160] If the brake pedal depth is greater than a preset depth threshold and the longitudinal acceleration is less than a preset acceleration threshold, it is determined that the road adhesion state of the road on which the vehicle is traveling is the first adhesion state.

[0161] The specific definitions of the road surface adhesion state determination device can be found in the definitions of the road surface adhesion state determination method described above and will not be further elaborated here. Each module within the aforementioned road surface adhesion state determination device may be implemented in whole or in part via software, hardware, or a combination thereof. Each of these modules may be embedded in or independent of a processor within a computer device in hardware form, or may be stored in a computer device memory in software form, allowing the processor to invoke and execute the corresponding operations of each module.

[0162] In one embodiment, a device for determining road adhesion status is provided. The device may be a vehicle control unit (VCU) and includes a processor, memory, and a database connected via a system bus. The processor of the device provides computing and control capabilities. The memory of the device includes a non-volatile storage medium and internal memory. The non-volatile storage medium stores an operating system, a computer program, and a database. The internal memory provides an environment for the operating system and computer program stored in the non-volatile storage medium. The database of the device contains data such as vehicle posture parameters and acceleration ranges. When executed by the processor, the computer program implements a method for determining road adhesion status.

[0163] In one embodiment, Figure 5 As shown, a road surface adhesion state determination device is provided, including a memory, a processor, and a computer program stored in the memory and executable on the processor. When the processor executes the computer program, the steps of the road surface adhesion state determination method are implemented.

[0164] In one embodiment, a computer-readable storage medium is provided, on which a computer program is stored. When the computer program is executed by a processor, the steps of the above-mentioned road surface adhesion state determination method are implemented.

[0165] Those skilled in the art will appreciate that all or part of the processes in the above-mentioned embodiments can be implemented by instructing the relevant hardware through a computer program. The computer program can be stored in a non-volatile computer-readable storage medium. When the computer program is executed, it can include the processes of the embodiments of the above-mentioned methods. Among them, any reference to memory, storage, database or other media used in the embodiments provided in this application can include non-volatile and / or volatile memory. Non-volatile memory can include read-only memory (ROM), programmable ROM (PROM), electrically programmable ROM (EPROM), electrically erasable programmable ROM (EEPROM) or flash memory. Volatile memory can include random access memory (RAM) or external cache memory. By way of illustration and not limitation, RAM is available in various forms, such as static RAM (SRAM), dynamic RAM (DRAM), synchronous DRAM (SDRAM), double data rate SDRAM (DDRSDRAM), enhanced SDRAM (ESDRAM), synchronous link (Synchlink) DRAM (SLDRAM), memory bus (Rambus) direct RAM (RDRAM), direct memory bus dynamic RAM (DRDRAM), and memory bus dynamic RAM (RDRAM).

[0166] Those skilled in the art will clearly understand that for the sake of convenience and brevity of description, only the division of the above-mentioned functional units and modules is used as an example. In actual applications, the above-mentioned functions can be distributed and completed by different functional units and modules as needed, that is, the internal structure of the device can be divided into different functional units or modules to complete all or part of the functions described above.

[0167] The embodiments described above are only used to illustrate the technical solutions of the present invention, rather than to limit the same. 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. 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 various embodiments of the present invention, and should all be included in the scope of protection of the present invention.

Claims

1. A method for determining road adhesion state, characterized in that: include: Obtain the longitudinal acceleration of the vehicle during driving, as well as the function activation signal of the vehicle electronic stability system; determining a driving state of the vehicle, and determining, based on the function activation signal, whether a function corresponding to the driving state in the vehicle electronic stability system is in an activated state; If the function corresponding to the driving state in the vehicle electronic stability system is activated, determining the road adhesion state of the vehicle driving road according to the longitudinal acceleration of the vehicle; After determining the driving state of the vehicle and determining whether a function corresponding to the driving state in the vehicle electronic stability system is activated according to the function activation signal, the method further includes: If a function corresponding to the driving state in the vehicle electronic stability system is in an inactive state, determining a road adhesion state of the road surface on which the vehicle is traveling based on the wheel speed or longitudinal acceleration of the vehicle; Wherein, determining the road adhesion state of the vehicle based on the wheel speed or longitudinal acceleration of the vehicle includes: When the vehicle is in a driving state and a traction control function in the vehicle electronic stability system is in an inactive state, determining a slip rate of the vehicle based on wheel speeds of the vehicle, and determining the road adhesion state based on the slip rate; When the driving state of the vehicle is a braking state and the anti-lock control function in the vehicle body electronic stability system is in an inactive state, determining the road surface adhesion state according to the longitudinal acceleration of the vehicle and the brake pedal depth; When the vehicle is in a coasting state and the coasting recovery torque verification function in the vehicle electronic stability system is in an inactive state, the slip rate of the vehicle is determined based on the wheel speed of the vehicle, and the road adhesion state is determined based on the slip rate.

2. The method for determining the road surface adhesion state according to claim 1, wherein: When the vehicle is in a driving state and a traction control function in the vehicle body electronic stability system is activated, determining the road adhesion state of the road surface on which the vehicle is traveling based on the longitudinal acceleration of the vehicle includes: determining whether the traction control function is in a stable control state; If the traction control function is in a stable control state, the road adhesion state of the road surface on which the vehicle is traveling is determined according to the acceleration range in which the longitudinal acceleration of the vehicle is located.

3. The method for determining the road surface adhesion state according to claim 2, wherein: The determining, based on the acceleration interval in which the longitudinal acceleration of the vehicle is located, a road surface adhesion state of the vehicle, includes: If the longitudinal acceleration is in a first acceleration range, determining that the road adhesion state is a first adhesion state; If the longitudinal acceleration is in a second acceleration range, determining that the road adhesion state is a second adhesion state, the second acceleration range is smaller than the first acceleration range, and the road adhesion force corresponding to the second adhesion state is smaller than the road adhesion force corresponding to the first adhesion state; If the longitudinal acceleration is in a third acceleration range, the road adhesion state is determined to be a third adhesion state, the third acceleration range is smaller than the second acceleration range, and the road adhesion force corresponding to the third adhesion state is smaller than the road adhesion force corresponding to the second adhesion state.

4. The method for determining the road surface adhesion state according to claim 1, wherein: When the vehicle is in a braking state and an anti-lock braking control function in the vehicle body electronic stability system is activated, determining the road adhesion state of the road surface on which the vehicle is traveling based on the longitudinal acceleration of the vehicle includes: If the longitudinal acceleration is in a fourth acceleration interval, determining that the road adhesion state is a first adhesion state; If the longitudinal acceleration is in a fifth acceleration interval, determining that the road adhesion state is a second adhesion state, and the fifth acceleration interval is greater than the fourth acceleration interval; If the longitudinal acceleration is in the sixth acceleration interval, it is determined that the road adhesion state is the third adhesion state, and the sixth acceleration interval is greater than the fifth acceleration interval.

5. The method for determining the road surface adhesion state according to claim 1, wherein: When the vehicle is in a coasting state and a coasting recovery torque verification function in the vehicle electronic stability system is activated, determining the road adhesion state of the road surface on which the vehicle is traveling based on the longitudinal acceleration of the vehicle includes: If it is determined that the longitudinal acceleration is in the seventh acceleration interval, determining that the road adhesion state is the second adhesion state; If it is determined that the longitudinal acceleration is in the eighth acceleration interval, the road adhesion state is determined to be the third adhesion state, and the eighth acceleration interval is greater than the seventh acceleration interval.

6. The method for determining the road surface adhesion state according to claim 1, wherein: The determining the road surface adhesion state according to the longitudinal acceleration of the vehicle and the brake pedal depth includes: determining whether the brake pedal depth is greater than a preset depth threshold, and determining whether the longitudinal acceleration is less than a preset acceleration threshold; If the brake pedal depth is greater than a preset depth threshold and the longitudinal acceleration is less than a preset acceleration threshold, it is determined that the road adhesion state of the vehicle driving on the road is a first adhesion state.

7. A road surface adhesion state determination device, characterized in that: include: An acquisition module is used to obtain the longitudinal acceleration of the vehicle during driving and the function activation signal of the vehicle body electronic stability system; a first determining module, configured to determine a driving state of the vehicle and determine, based on the function activation signal, whether a function corresponding to the driving state in the vehicle electronic stability system is in an activated state; a second determining module configured to determine a road adhesion state of a road surface on which the vehicle is traveling based on a longitudinal acceleration of the vehicle if a function corresponding to the driving state in the vehicle electronic stability system is activated; The road adhesion state determination device further includes a third determination module. After determining the driving state of the vehicle and determining whether the function corresponding to the driving state in the vehicle electronic stability system is activated according to the function activation signal, the third determination module is specifically configured to: If the function corresponding to the driving state in the vehicle electronic stability system is in an inactive state, determining the road adhesion state of the road the vehicle is traveling on based on the wheel speed or longitudinal acceleration of the vehicle; The third determining module is specifically configured to: When the vehicle is in driving mode and the traction control function in the electronic stability system is not activated, the vehicle's slip rate is determined based on the vehicle's wheel speed, and the road adhesion state is determined based on the slip rate; When the vehicle is in braking mode and the anti-lock braking system (ABS) function is inactive, the road adhesion state is determined based on the vehicle's longitudinal acceleration and brake pedal depth. When the vehicle is coasting and the coasting regenerative torque calibration function in the vehicle's electronic stability system is inactive, the vehicle's slip ratio is determined based on the vehicle's wheel speed, and the road adhesion state is determined based on the slip ratio.

8. A road surface adhesion state determination device, comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, characterized in that: When the processor executes the computer program, the steps of the road surface adhesion state determination method according to any one of claims 1 to 6 are implemented.

9. A readable storage medium storing a computer program, characterized in that: When the computer program is executed by a processor, the steps of the road surface adhesion state determination method according to any one of claims 1 to 6 are implemented.

Images