Parameter calibration method and device of brake system

Abstract

The application provides a parameter calibration method and device of a brake system, in the application, vehicle running information of a host vehicle and a preceding vehicle at a current time is calculated through a vehicle kinematics model, real-time collision time of the host vehicle and the preceding vehicle is calculated according to the vehicle running information of the host vehicle and the preceding vehicle at the current time, a partial braking TTC threshold and a full braking TTC threshold are obtained, and an execution strategy of an actuator model is determined based on a size relationship among the real-time collision time, the partial braking TTC threshold and the full braking TTC threshold, so that the actuator model is controlled to operate according to the execution strategy, and when the host vehicle is parked, the partial braking TTC threshold and the full braking TTC threshold are adjusted based on a relative position of the host vehicle and the preceding vehicle when the host vehicle is parked. That is, through the application, the partial braking TTC threshold and the full braking TTC threshold can be calibrated automatically, and compared with a manual calibration method on a real vehicle, the calibration is simple and efficient.

Description

Technical Field

[0001] This invention relates to the field of virtual calibration, and more specifically, to a method and apparatus for calibrating parameters of a braking system. Background Technology

[0002] The core parameter of an automatic emergency braking system (AEB) is the braking TTC (Time to Collision) threshold. For graded braking AEB systems, the TTC threshold is divided into partial braking TTC threshold and full braking TTC threshold.

[0003] When using a graded braking AEB system, it is necessary to pre-calibrate the partial braking TTC threshold and the full braking TTC threshold. Calibration can be performed using a real vehicle. However, due to the presence of partial braking TTC in a graded braking AEB system, the partial braking TTC will affect the vehicle speed at the moment of full braking triggering, thus affecting the full braking TTC threshold. Therefore, the calibration process for graded braking is more complex than that for single-stage braking, requiring multiple manual calibrations, which is cumbersome and inefficient. Summary of the Invention

[0004] In view of this, the present invention provides a method and apparatus for calibrating the parameters of a braking system to solve the problem that graded braking requires repeated manual calibration, which is complicated and inefficient.

[0005] To solve the above-mentioned technical problems, the present invention adopts the following technical solution:

[0006] A method for calibrating parameters of a braking system, comprising:

[0007] The vehicle's operating information at the current moment is calculated using a vehicle kinematics model, which is used to calculate the vehicle's and the vehicle in front's position.

[0008] Based on the vehicle operation information of the self-vehicle and the preceding vehicle at the current moment, calculate the real-time collision time between the self-vehicle and the preceding vehicle;

[0009] The partial braking TTC threshold and the full braking TTC threshold are obtained, and the execution strategy of the actuator model is determined based on the relationship between the real-time collision time, the partial braking TTC threshold and the full braking TTC threshold, so as to control the actuator model to run according to the execution strategy.

[0010] When the vehicle is parked, the partial braking TTC threshold and the full braking TTC threshold are adjusted based on the relative position of the vehicle and the vehicle in front when the vehicle is parked.

[0011] Optionally, the vehicle's and the preceding vehicle's driving information at the current moment are calculated using a vehicle kinematics model, including:

[0012] Based on the vehicle's operating information at the previous moment, calculate the vehicle's operating information at the current moment;

[0013] Based on the vehicle's operating information at the previous moment, calculate the vehicle's operating information at the current moment; the vehicle's operating information includes speed, position, and acceleration.

[0014] Optionally, the real-time collision time between the self-vehicle and the preceding vehicle is calculated based on their respective vehicle operation information at the current moment, including:

[0015] Calculate the relative position based on the positions of the vehicle and the vehicle in front;

[0016] Calculate the relative speed based on the speeds of the vehicle and the vehicle in front;

[0017] Calculate the relative acceleration based on the accelerations of the vehicle and the vehicle in front;

[0018] The real-time collision time is calculated based on at least one of the relative position, the relative vehicle speed, and the relative acceleration.

[0019] Optionally, the real-time collision time is calculated based on at least one of the relative position, the relative vehicle speed, and the relative acceleration, including:

[0020] When the acceleration of the vehicle in front is zero, the collision time is calculated based on the relative position and the relative vehicle speed;

[0021] When the acceleration of the vehicle in front is not zero, the enhanced distance collision time is calculated based on the relative position, the relative vehicle speed, and the relative acceleration.

[0022] Optionally, the partial braking TTC threshold and the full braking TTC threshold are obtained, including:

[0023] Based on the vehicle speed and the relative vehicle speed, the partial braking TTC threshold and the full braking TTC threshold are obtained by looking up the table.

[0024] Optionally, based on the relationship between the real-time collision time, the partial braking TTC threshold, and the full braking TTC threshold, the execution strategy of the actuator model is determined, including:

[0025] If the real-time collision time is simultaneously greater than both the partial braking TTC threshold and the full braking TTC threshold, the execution strategy of the actuator model is determined to be empty.

[0026] If the real-time collision time is less than the partial braking TTC threshold but greater than the full braking TTC threshold, the execution strategy of the actuator model is determined to be the partial braking strategy.

[0027] If the real-time collision time is less than the full braking TTC threshold, the execution strategy of the actuator model is determined to be the full braking strategy.

[0028] Optionally, controlling the executor model to operate according to the execution strategy includes:

[0029] When the execution strategy is empty, the actuator model is controlled not to perform braking operation;

[0030] When the execution strategy is a partial braking strategy, the actuator model is controlled to perform braking operation according to the braking curve corresponding to the first deceleration;

[0031] When the execution strategy is a full braking strategy, the actuator model is controlled to perform braking operation according to the braking curve corresponding to the second deceleration; the second deceleration is greater than the first deceleration.

[0032] Optionally, controlling the actuator model to perform braking operations according to the braking curve corresponding to the first deceleration includes:

[0033] The actuator model is controlled to obtain the braking curve corresponding to the first deceleration determined by the fitting method, and the braking operation is performed according to the braking curve.

[0034] Optionally, based on the relative positions of the self-driving vehicle and the preceding vehicle when the self-driving vehicle is parked, the partial braking TTC threshold and the full braking TTC threshold are adjusted, including:

[0035] Obtain the target function f t =(SL) 2 Wherein, L is the reference relative position of the self-driving vehicle and the vehicle in front when the self-driving vehicle is parked, and S is the relative position of the self-driving vehicle and the vehicle in front when the self-driving vehicle is parked;

[0036] Calculate the objective function value of the vehicle at the current parking time, and obtain the objective function values ​​of the vehicle at previous parking times;

[0037] If the TTC threshold traversal is not completed, the partial braking TTC threshold and the full braking TTC threshold are dynamically adjusted according to the preset step size.

[0038] If the TTC threshold traversal is complete, then the partial braking TTC threshold and the full braking TTC threshold corresponding to the minimum objective function value among the objective function values ​​of the vehicle at this parking time and the objective function values ​​of the historical parking times will be output.

[0039] A parameter calibration device for a braking system, comprising:

[0040] The information acquisition module is used to calculate the vehicle operation information of the vehicle and the vehicle in front at the current moment through the vehicle kinematics model;

[0041] The time calculation module is used to calculate the real-time collision time between the self-vehicle and the preceding vehicle based on the vehicle operation information of the self-vehicle and the preceding vehicle at the current moment.

[0042] The braking control module is used to acquire the partial braking TTC threshold and the full braking TTC threshold, and based on the relationship between the real-time collision time, the partial braking TTC threshold and the full braking TTC threshold, determine the execution strategy of the actuator model, so as to control the actuator model to run according to the execution strategy.

[0043] The threshold adjustment module is used to adjust the partial braking TTC threshold and the full braking TTC threshold based on the relative position of the vehicle and the vehicle in front when the vehicle is parked.

[0044] Compared with the prior art, the present invention has the following beneficial effects:

[0045] This invention provides a method and apparatus for calibrating parameters of a braking system. In this invention, the vehicle's kinematics model is used to calculate the vehicle's and the preceding vehicle's operational information at the current moment. Based on this information, the real-time collision time (TTC) of the two vehicles is calculated, and partial braking TTC thresholds and full braking TTC thresholds are obtained. Based on the relationship between the real-time collision time, the partial braking TTC threshold, and the full braking TTC threshold, an execution strategy for the actuator model is determined to control the actuator model to operate according to this strategy. When the vehicle is stopped, the partial braking TTC threshold and the full braking TTC threshold are adjusted based on the relative positions of the vehicle and the preceding vehicle at the time of stopping. In other words, this invention enables automatic calibration of the partial braking TTC threshold and the full braking TTC threshold, which is simpler and more efficient than manual calibration on a real vehicle. Attached Figure Description

[0046] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the provided drawings without creative effort.

[0047] Figure 1 A flowchart of a parameter calibration method for a braking system provided in an embodiment of the present invention;

[0048] Figure 2 A flowchart of a method for calculating real-time collision time provided in an embodiment of the present invention;

[0049] Figure 3 This is a schematic diagram of deceleration provided in an embodiment of the present invention;

[0050] Figure 4 A model interaction diagram provided in an embodiment of the present invention;

[0051] Figure 5 Another model interaction diagram provided in this embodiment of the invention;

[0052] Figure 6 This is a schematic diagram of the structure of a parameter calibration device for a braking system provided in an embodiment of the present invention. Detailed Implementation

[0053] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0054] Assisted driving vehicles can effectively reduce traffic accident rates, especially the Automatic Emergency Braking (AEB) system, which greatly reduces rear-end collisions, and AEB technology has been successfully implemented.

[0055] The core parameter of an AEB system is the braking TTC (Time to Collision) threshold. For a graded braking AEB system, the TTC threshold is divided into a partial braking TTC threshold and a full braking TTC threshold.

[0056] When using a multi-stage braking AEB system, it is necessary to pre-calibrate the partial braking TTC threshold and the full braking TTC threshold. Calibration can be performed using a real-vehicle calibration method. For multi-stage braking AEB systems, OEMs spend a significant amount of time calibrating them on real vehicles. This is primarily because multi-stage braking is more complex than single-stage braking calibration. Multi-stage braking consists of partial braking and full braking. The complexity arises from the presence of partial braking TTC. Partial braking TTC affects the vehicle speed at the full braking trigger point, deviating from the test speed. Vehicle speed, in turn, influences the full braking TTC threshold. This coupling relationship between partial and full braking ultimately means that the vehicle's stopping distance cannot be simply calculated using physical formulas as with single-stage braking. This complexity significantly increases the need for repeated manual calibration of the AEB system, resulting in complex operations and low efficiency.

[0057] To address this issue, the inventors discovered that a virtual automatic calibration method can be used to calibrate the partial braking TTC threshold and the full braking TTC threshold. Specifically, simulation can be used to perform virtual automatic calibration relatively quickly and conveniently, reducing the repetitive workload of calibration personnel, improving efficiency, and achieving cost reduction and efficiency improvement.

[0058] However, virtual automatic calibration methods require high model accuracy. This method necessitates establishing kinematic models of the vehicle and the preceding vehicle, sensor models, controller models, and actuator models. The biggest problem with virtual automatic calibration is its inability to fully consider the working characteristics of the actual vehicle and its components, resulting in real-time simulations that cannot accurately simulate real-world scenarios. This invention establishes a vehicle kinematic model, sensor model, and controller model using physical modeling. For the Electronic Stability Program (ESP), it employs both empirical and physical modeling methods to build actuator models. During model simulation, this provides a more reliable guide for the calibration of the actual vehicle's AEB system.

[0059] Specifically, this invention provides a method and apparatus for calibrating parameters of a braking system. In this invention, the vehicle's kinematics model is used to calculate the vehicle's and the preceding vehicle's operational information at the current moment. Based on this information, the real-time collision time between the two vehicles is calculated, and partial braking TTC thresholds and full braking TTC thresholds are obtained. Based on the relationship between the real-time collision time, the partial braking TTC threshold, and the full braking TTC threshold, an execution strategy for the actuator model is determined to control the actuator model to operate according to this strategy. When the vehicle is stopped, the partial braking TTC threshold and the full braking TTC threshold are adjusted based on the relative positions of the vehicle and the preceding vehicle at the time of stopping. In other words, this invention enables automatic calibration of the partial braking TTC threshold and the full braking TTC threshold, which is simpler and more efficient than manual calibration on a real vehicle.

[0060] Based on the above, this invention provides a parameter calibration method for a braking system, applied to a virtual parameter calibration device, which can be a controller, computer, or other similar device. The virtual parameter calibration device runs a vehicle kinematics model, a sensor model, a controller model, and an actuator model. Furthermore, the braking system can be an automatic emergency braking system.

[0061] Reference Figure 1 A method for calibrating the parameters of a braking system may include:

[0062] S11. Calculate the vehicle operation information of the vehicle and the vehicle in front at the current moment using the vehicle kinematics model.

[0063] The vehicle kinematics model includes a self-vehicle model and a preceding vehicle model.

[0064] The vehicle's movement information at the current moment is calculated using a vehicle kinematics model, including:

[0065] The vehicle model is used to calculate the vehicle's current operating information based on the vehicle's operating information at the previous moment.

[0066] The preceding vehicle model is used to calculate the preceding vehicle's current vehicle operation information based on the preceding vehicle's operation information at the previous moment.

[0067] Specifically, the vehicle operation information includes vehicle speed, position, and acceleration. The calculation process is the same whether calculating the vehicle's own information or that of the preceding vehicle; only the models used differ. The vehicle's model calculates its own vehicle's operation information at the current moment, while the preceding vehicle's model calculates the preceding vehicle's operation information at the current moment.

[0068] The specific process for calculating vehicle operation information is as follows:

[0069] The self-vehicle model and the preceding vehicle model calculate the vehicle's current position, speed, and acceleration information based on the vehicle's position, speed, and acceleration information from the previous moment.

[0070] V t =V t-1 +a t-l ·Δt (1)

[0071] S t =S t-1 +V t-1 ·Δt (2)

[0072] Among them, V t It is the vehicle speed at the current moment, V t-1 It is the vehicle speed at the previous moment, a t-1 It is the acceleration at the previous moment (or deceleration when the acceleration is negative), Δt is the step size, and S is the acceleration at the previous moment. t It is the current position, S t-1 It is the position at the previous moment.

[0073] The positions and velocities of the vehicle and the vehicle in front at the current moment can be calculated using formulas 1 and 2, and the acceleration values ​​can be obtained directly.

[0074] S12. Calculate the real-time collision time between the self-vehicle and the preceding vehicle based on their respective vehicle operation information at the current moment.

[0075] Specifically, step S12 can be performed using the sensor model described above.

[0076] For the body, step S12 may include:

[0077] S21. Calculate the relative position based on the positions of the vehicle and the vehicle in front.

[0078] Specifically, Δs(t) represents the relative position of the vehicle and the vehicle in front, and the difference between the positions of the vehicle and the vehicle in front is Δs(t).

[0079] S22. Calculate the relative speed based on the speeds of the vehicle and the vehicle in front.

[0080] Specifically, v T (t) represents the speed of the vehicle in front at time t, v E Δv(t) is the vehicle speed at time t, and Δv(t) is the relative distance between the vehicle and the vehicle in front. Δv(t) = v T (t)-v E (t).

[0081] S23. Calculate the relative acceleration based on the acceleration of the vehicle and the vehicle in front.

[0082] a T (t) is the acceleration of the vehicle in front at time t, a E (t) is the vehicle's acceleration at time t, and the relative acceleration = a T (t)-a E (t).

[0083] S24. Calculate the real-time collision time based on at least one of the relative position, the relative vehicle speed, and the relative acceleration.

[0084] In practical applications, the formula for calculating the real-time collision time is determined based on whether the vehicle in front has acceleration.

[0085] When the acceleration of the preceding vehicle is zero, the collision time (TTC) is calculated based on the relative position and the relative vehicle speed.

[0086] Right now:

[0087]

[0088] When the acceleration of the vehicle in front is not zero, the Enhanced Time to Collision (ETTC) is calculated based on the relative position, the relative speed, and the relative acceleration.

[0089] Right now:

[0090] S13. Obtain the partial braking TTC threshold and the full braking TTC threshold, and determine the execution strategy of the actuator model based on the relationship between the real-time collision time, the partial braking TTC threshold and the full braking TTC threshold, so as to control the actuator model to run according to the execution strategy.

[0091] Specifically, the controller model is invoked to execute step S13. The controller model can look up the table to obtain the partial braking TTC threshold and the full braking TTC threshold based on the vehicle speed and the relative vehicle speed.

[0092] In detail, based on the vehicle's speed v E (t), the relative vehicle distance Δv(t) between the vehicle and the vehicle in front, and the partial braking TTC threshold and the full braking TTC threshold initially set based on experience at the current time are calculated by looking up the table.

[0093] f s (TTC) = [v E (t), Δv(t)] (5)

[0094] f f (TTC) = [v E (t),Δv(t)] (6)

[0095] Among them, f s (TTC) is the partial braking TTC threshold, f f (TTC) is the TTC threshold for full braking.

[0096] In another implementation of the present invention, the execution strategy of the actuator model is determined based on the relationship between the real-time collision time, the partial braking TTC threshold, and the full braking TTC threshold, which may include:

[0097] 1) If the real-time collision time is greater than both the partial braking TTC threshold and the full braking TTC threshold, the execution strategy of the actuator model is determined to be empty.

[0098] 2) If the real-time collision time is less than the partial braking TTC threshold and greater than the full braking TTC threshold, the execution strategy of the actuator model is determined to be the partial braking strategy.

[0099] 3) If the real-time collision time is less than the full braking TTC threshold, the execution strategy of the actuator model is determined to be the full braking strategy.

[0100] Specifically, the calculated real-time TTC or ETTC value is compared with the partial braking TTC threshold and the full braking TTC threshold calculated by looking up the table.

[0101] When the real-time TTC or ETTC value is greater than the partial braking TTC threshold and the full braking TTC threshold, the AEB function is not triggered, that is, the execution strategy of the actuator model is empty.

[0102] When the real-time TTC or ETTC value is less than the partial braking TTC threshold but greater than the full braking TTC threshold, the AEB partial braking function is triggered, and a deceleration request is issued. In this case, the actuator model's execution strategy is the partial braking strategy. The partial braking function primarily addresses the potential harm to the vehicle caused by excessive braking force provided by the full braking function, while simultaneously coordinating with full braking to reduce speed and avoid collisions. The partial braking function is empirically set to a first deceleration value, such as -3 m / s². 2 .

[0103] When the real-time TTC or ETTC value is less than the full braking TTC threshold, the AEB full braking function is triggered, and a deceleration request is issued. At this time, the execution strategy of the actuator model is the full braking strategy. Based on experience, the full braking deceleration value in the full braking strategy is set as the second deceleration, such as -10m / s². 2 .

[0104] The deceleration value in this step can be determined using the deceleration request calculation module in the controller model.

[0105] Specifically, controlling the executor model to operate according to the execution strategy includes:

[0106] When the execution strategy is empty, the actuator model is controlled not to perform braking operation;

[0107] When the execution strategy is a partial braking strategy, the actuator model is controlled to perform braking operations according to the braking curve corresponding to the first deceleration. Specifically, the actuator model can be controlled to obtain the braking curve corresponding to the first deceleration determined by a fitting method, and perform braking operations according to the braking curve.

[0108] When the execution strategy is a full braking strategy, the actuator model is controlled to perform braking operations according to the braking curve corresponding to the second deceleration; the second deceleration is greater than the first deceleration. Similarly, the braking curve corresponding to the second deceleration can be determined using a fitting method, and braking operations can be performed according to the braking curve.

[0109] In practical applications, the above execution strategy is output to the ESP system, i.e., the actuator model. The actuator model cannot provide a step response of -3m / s. 2 or -10m / s 2 The deceleration value is obtained by the actuator model based on its own characteristics and outputting the actual deceleration value. The actual response deceleration value is calculated by looking up the table based on the requested deceleration value and the time.

[0110] f a =(a r ,t) (7)

[0111] Among them, f a It is the deceleration of the actuator model response, a r It is the deceleration value in the execution strategy, and t is time.

[0112] The braking curve used in the actuator model, namely the ESP braking characteristic curve, is generated by fitting multiple characteristic curves collected from the vehicle's partial and full braking at different speeds using AEB (Autonomous Emergency Braking). In practical applications, the ESP braking characteristic curve can be changed according to the vehicle model to calculate the actual deceleration for different models. Figure 3 As shown.

[0113] The requested deceleration is the deceleration value in the execution strategy. The actuator model cannot respond to this deceleration value all at once. It needs to use the actuator delay module to gradually decelerate according to the ESP braking characteristic curve, and decelerate to the deceleration value in the execution strategy at the actual deceleration in the ESP braking characteristic curve.

[0114] S14. When the vehicle is parked, adjust the partial braking TTC threshold and the full braking TTC threshold based on the relative position of the vehicle and the vehicle in front when the vehicle is parked.

[0115] Specifically, based on the relative positions of the self-driving vehicle and the vehicle in front when the self-driving vehicle is parked, the partial braking TTC threshold and the full braking TTC threshold are adjusted, including:

[0116] 1) Obtain the objective function f t =(SL) 2 .

[0117] Wherein, L is the reference relative position of the self-driving vehicle and the vehicle in front when the self-driving vehicle is parked, and S is the relative position of the self-driving vehicle and the vehicle in front when the self-driving vehicle is parked, that is, the actual relative position of the two.

[0118] Ideally, the reference relative position L can be 1.2 meters. In practical applications, if the relative position S is controlled within the empirical range of 1.2 meters, it indicates that the partially braking TTC threshold and the fully braking TTC threshold set above are reasonable. However, in practical applications, it may be necessary to adjust the partially braking TTC threshold and the fully braking TTC threshold multiple times to ensure that S is controlled within 1.2 meters.

[0119] 2) Calculate the objective function value of the vehicle at the current parking time, and obtain the objective function values ​​of the vehicle at previous parking times.

[0120] After the actuator model operates according to the execution strategy, it will generate new acceleration, vehicle speed and position. The calculated real-time deceleration value will be transmitted to the vehicle kinematics model to form a closed loop. In the next acquisition cycle, the corresponding data will be obtained again through the self-vehicle model and the preceding vehicle model. The new real-time collision time will be calculated through the sensor model. The controller model will determine the new execution strategy of the actuator model again and repeat this step until the self-vehicle stops.

[0121] After the vehicle stops, the real-time speed and position of the vehicle can be recalculated based on the vehicle kinematics model. The controller model obtains the actual relative position of the vehicle and the vehicle in front by subtracting the position of the vehicle in front from the position of the vehicle in front.

[0122] Then, the objective function value is calculated. However, before this stop, the vehicle may have stopped multiple times in a loop, so the objective function values ​​from the vehicle's previous stops can be obtained.

[0123] 3) If the TTC threshold traversal is not completed, the partial braking TTC threshold and the full braking TTC threshold are dynamically adjusted according to the preset step size.

[0124] In this embodiment, the traversal range of the partial braking TTC threshold and the full braking TTC threshold is set, such as: the adjustment step size is 0.1 seconds, the adjustment range is 0.5 seconds to 2 seconds, and the partial braking TTC threshold and the full braking TTC threshold are traversed in sequence.

[0125] After iterating through the partial braking TTC threshold and the full braking TTC threshold in sequence, the partial braking TTC threshold and the full braking TTC threshold corresponding to the smallest objective function value are selected as the optimal partial braking TTC threshold and the optimal full braking TTC threshold.

[0126] If at least one of the partial braking TTC thresholds and the full braking TTC threshold has not been traversed, the partial braking and full braking TTC thresholds are continuously traversed by dynamically adjusting the partial braking and full braking TTC thresholds in a step size of 0.1 seconds and an adjustment range of 0.5 seconds to 2 seconds.

[0127] For example, the TTC threshold range for partial braking is 0.5 seconds to 2 seconds, and the TTC threshold range for full braking is 0.5 seconds to 2 seconds. The TTC threshold for partial braking starts from 0.5 seconds and gradually increases by 0.1 seconds. The TTC threshold for full braking starts from 0.5 seconds and iterates in steps of 0.1 seconds within the range. The objective function is calculated once in each iteration, and the minimum value of the objective function is sought through iterative iteration.

[0128] 4) If the TTC threshold traversal is completed, output the partial braking TTC threshold and the full braking TTC threshold corresponding to the minimum objective function value among the objective function values ​​of the vehicle at the current stop and the objective function values ​​of the historical stops.

[0129] If the partial braking TTC threshold and the full braking TTC threshold are iterated through sequentially, the partial braking TTC threshold and the full braking TTC threshold corresponding to the minimum objective function value are determined. When the objective function value reaches its minimum, it indicates that the partial braking TTC threshold and the full braking TTC threshold are most reasonable. At this point, the partial braking TTC threshold and the full braking TTC threshold are output, thus completing the virtual automatic calibration.

[0130] The specific interaction process of the above-mentioned vehicle model, front vehicle model, sensor model, controller model, and actuator model can be referred to... Figure 4 and Figure 5 For specific work procedures, please refer to the corresponding instructions above.

[0131] In this embodiment, the vehicle kinematics model is used to calculate the vehicle movement information of the self-vehicle and the preceding vehicle at the current moment. Based on the vehicle movement information of the self-vehicle and the preceding vehicle at the current moment, the real-time collision time of the self-vehicle and the preceding vehicle is calculated, and the partial braking TTC threshold and the full braking TTC threshold are obtained. Based on the relationship between the real-time collision time, the partial braking TTC threshold, and the full braking TTC threshold, the execution strategy of the actuator model is determined to control the actuator model to operate according to the execution strategy. When the self-vehicle is stopped, the partial braking TTC threshold and the full braking TTC threshold are adjusted based on the relative position of the self-vehicle and the preceding vehicle when the self-vehicle is stopped. That is, through this invention, the partial braking TTC threshold and the full braking TTC threshold can be automatically calibrated, which is simpler to operate and more efficient than the method of repeated calibration on a real vehicle.

[0132] Furthermore, driver assistance systems will be installed and used in more and more mass-produced vehicles, and AEB systems have become standard equipment. The AEB virtual automatic calibration method in this invention effectively reduces the workload of calibrating the AEB system in real vehicles. Calibration personnel no longer need to rely on experience to calibrate the partial braking TTC threshold and the full braking TTC threshold through trial and error. This method has a more obvious guiding effect on technicians who are just entering the calibration position. Moreover, this invention can be configured according to different development platforms and different vehicle models, and is a universal virtual automatic calibration method. This invention has significant implications for automobile companies to reduce development costs and shorten development cycles.

[0133] Optionally, based on the embodiments of the above-described braking system parameter calibration method, another embodiment of the present invention provides a braking system parameter calibration device, referring to... Figure 6 It can include:

[0134] The information acquisition module 11 is used to calculate the vehicle operation information of the vehicle and the vehicle in front at the current moment through the vehicle kinematics model;

[0135] The time calculation module 12 is used to calculate the real-time collision time between the self-vehicle and the preceding vehicle based on the vehicle operation information of the self-vehicle and the preceding vehicle at the current time.

[0136] The braking control module 13 is used to acquire the partial braking TTC threshold and the full braking TTC threshold, and based on the relationship between the real-time collision time, the partial braking TTC threshold and the full braking TTC threshold, determine the execution strategy of the actuator model, so as to control the actuator model to run according to the execution strategy.

[0137] The threshold adjustment module 14 is used to adjust the partial braking TTC threshold and the full braking TTC threshold based on the relative position of the vehicle and the vehicle in front when the vehicle is parked.

[0138] Furthermore, the information acquisition module 11 is specifically used for:

[0139] Based on the vehicle's operating information at the previous moment, calculate the vehicle's operating information at the current moment;

[0140] Based on the vehicle's operating information at the previous moment, calculate the vehicle's operating information at the current moment; the vehicle's operating information includes speed, position, and acceleration.

[0141] Furthermore, the time calculation module 12 is specifically used for:

[0142] Calculate the relative position based on the positions of the vehicle and the vehicle in front;

[0143] Calculate the relative speed based on the speeds of the vehicle and the vehicle in front;

[0144] Calculate the relative acceleration based on the accelerations of the vehicle and the vehicle in front;

[0145] The real-time collision time is calculated based on at least one of the relative position, the relative vehicle speed, and the relative acceleration.

[0146] Furthermore, when calculating the real-time collision time based on at least one of the relative position, the relative vehicle speed, and the relative acceleration, the time calculation module 12 is specifically used for:

[0147] When the acceleration of the vehicle in front is zero, the collision time is calculated based on the relative position and the relative vehicle speed;

[0148] When the acceleration of the vehicle in front is not zero, the enhanced distance collision time is calculated based on the relative position, the relative vehicle speed, and the relative acceleration.

[0149] Furthermore, when the braking control module 13 is used to obtain the partial braking TTC threshold and the full braking TTC threshold, it is specifically used for:

[0150] Based on the vehicle speed and the relative vehicle speed, the partial braking TTC threshold and the full braking TTC threshold are obtained by looking up the table.

[0151] Furthermore, when determining the execution strategy of the actuator model based on the relationship between the real-time collision time, the partial braking TTC threshold, and the full braking TTC threshold, the braking control module 13 is specifically used for:

[0152] If the real-time collision time is simultaneously greater than both the partial braking TTC threshold and the full braking TTC threshold, the execution strategy of the actuator model is determined to be empty.

[0153] If the real-time collision time is less than the partial braking TTC threshold but greater than the full braking TTC threshold, the execution strategy of the actuator model is determined to be the partial braking strategy.

[0154] If the real-time collision time is less than the full braking TTC threshold, the execution strategy of the actuator model is determined to be the full braking strategy.

[0155] Furthermore, the braking control module 13 is used to control the actuator model to run according to the execution strategy, specifically for:

[0156] When the execution strategy is empty, the actuator model is controlled not to perform braking operation;

[0157] When the execution strategy is a partial braking strategy, the actuator model is controlled to perform braking operation according to the braking curve corresponding to the first deceleration;

[0158] When the execution strategy is a full braking strategy, the actuator model is controlled to perform braking operation according to the braking curve corresponding to the second deceleration; the second deceleration is greater than the first deceleration.

[0159] Furthermore, when the braking control module 13 controls the actuator model to perform braking operations according to the braking curve corresponding to the first deceleration, it is specifically used for:

[0160] The actuator model is controlled to obtain the braking curve corresponding to the first deceleration determined by the fitting method, and the braking operation is performed according to the braking curve.

[0161] Furthermore, the threshold adjustment module 14 includes:

[0162] The function retrieval submodule is used to retrieve the target function f. t =(SL) 2 Wherein, L is the reference relative position of the self-driving vehicle and the vehicle in front when the self-driving vehicle is parked, and S is the relative position of the self-driving vehicle and the vehicle in front when the self-driving vehicle is parked;

[0163] The function calculation submodule is used to calculate the objective function value of the vehicle at the current parking time, and to obtain the objective function values ​​of the vehicle at previous parking times;

[0164] The threshold adjustment submodule is used to dynamically adjust the partial braking TTC threshold and the full braking TTC threshold according to a preset step size if the TTC threshold traversal has not ended.

[0165] The threshold output submodule is used to output the partial braking TTC threshold and the full braking TTC threshold corresponding to the minimum objective function value among the objective function values ​​of the vehicle at the current stop and the objective function values ​​of the historical stops, if the TTC threshold traversal is completed.

[0166] In this embodiment, the vehicle kinematics model is used to calculate the vehicle movement information of the self-vehicle and the preceding vehicle at the current moment. Based on the vehicle movement information of the self-vehicle and the preceding vehicle at the current moment, the real-time collision time of the self-vehicle and the preceding vehicle is calculated, and the partial braking TTC threshold and the full braking TTC threshold are obtained. Based on the relationship between the real-time collision time, the partial braking TTC threshold, and the full braking TTC threshold, the execution strategy of the actuator model is determined to control the actuator model to operate according to the execution strategy. When the self-vehicle is stopped, the partial braking TTC threshold and the full braking TTC threshold are adjusted based on the relative position of the self-vehicle and the preceding vehicle when the self-vehicle is stopped. That is, through this invention, the partial braking TTC threshold and the full braking TTC threshold can be automatically calibrated, which is simpler to operate and more efficient than the method of repeated calibration on a real vehicle.

[0167] It should be noted that the working process of each module and sub-module of this method is described in the corresponding descriptions in the above embodiments, and will not be repeated here.

[0168] The above description of the disclosed embodiments enables those skilled in the art to make or use the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A method of calibrating parameters of a brake system, characterized in that, include: The vehicle's operating information at the current moment is calculated using a vehicle kinematics model, which is used to calculate the vehicle's and the vehicle in front's position. Based on the vehicle operation information of the self-vehicle and the preceding vehicle at the current moment, calculate the real-time collision time between the self-vehicle and the preceding vehicle; The partial braking TTC threshold and the full braking TTC threshold are obtained, and the execution strategy of the actuator model is determined based on the relationship between the real-time collision time, the partial braking TTC threshold and the full braking TTC threshold, so as to control the actuator model to run according to the execution strategy. When the vehicle is parked, the partial braking TTC threshold and the full braking TTC threshold are adjusted based on the relative position of the vehicle and the vehicle in front when the vehicle is parked. The adjustment of the partial braking TTC threshold and the full braking TTC threshold based on the relative positions of the self-driving vehicle and the preceding vehicle when the self-driving vehicle is parked includes: Obtain the target function Wherein, L is the reference relative position of the self-driving vehicle and the vehicle in front when the self-driving vehicle is parked, and S is the relative position of the self-driving vehicle and the vehicle in front when the self-driving vehicle is parked; Calculate the objective function value of the vehicle at the current parking time, and obtain the objective function values ​​of the vehicle at previous parking times; If the TTC threshold traversal is not completed, the partial braking TTC threshold and the full braking TTC threshold are dynamically adjusted according to the preset step size. If the TTC threshold traversal is complete, then the partial braking TTC threshold and the full braking TTC threshold corresponding to the minimum objective function value among the objective function values ​​of the vehicle at this parking time and the objective function values ​​of the historical parking times will be output.

2. The parameter calibration method according to claim 1, characterized in that, The vehicle's movement information at the current moment is calculated using a vehicle kinematics model, including: Based on the vehicle's operating information at the previous moment, calculate the vehicle's operating information at the current moment; Based on the vehicle's operating information at the previous moment, calculate the vehicle's operating information at the current moment; the vehicle's operating information includes speed, position, and acceleration.

3. The parameter calibration method according to claim 2, characterized in that, Based on the vehicle operation information of the self-vehicle and the preceding vehicle at the current moment, the real-time collision time between the self-vehicle and the preceding vehicle is calculated, including: Calculate the relative position based on the positions of the vehicle and the vehicle in front; Calculate the relative speed based on the speeds of the vehicle and the vehicle in front; Calculate the relative acceleration based on the accelerations of the vehicle and the vehicle in front; The real-time collision time is calculated based on at least one of the relative position, the relative vehicle speed, and the relative acceleration.

4. The parameter calibration method according to claim 3, characterized in that, Calculate the real-time collision time based on at least one of the relative position, relative vehicle speed, and relative acceleration, including: When the acceleration of the vehicle in front is zero, the collision time is calculated based on the relative position and the relative vehicle speed; When the acceleration of the vehicle in front is not zero, the enhanced distance collision time is calculated based on the relative position, the relative vehicle speed, and the relative acceleration.

5. The parameter calibration method according to claim 4, characterized in that, Obtain the partial braking TTC threshold and the full braking TTC threshold, including: Based on the vehicle speed and the relative vehicle speed, the partial braking TTC threshold and the full braking TTC threshold are obtained by looking up the table.

6. The parameter calibration method according to claim 5, characterized in that, Based on the relationship between the real-time collision time, the partial braking TTC threshold, and the full braking TTC threshold, the execution strategy of the actuator model is determined, including: If the real-time collision time is simultaneously greater than both the partial braking TTC threshold and the full braking TTC threshold, the execution strategy of the actuator model is determined to be empty. If the real-time collision time is less than the partial braking TTC threshold but greater than the full braking TTC threshold, the execution strategy of the actuator model is determined to be the partial braking strategy. If the real-time collision time is less than the full braking TTC threshold, the execution strategy of the actuator model is determined to be the full braking strategy.

7. The parameter calibration method according to claim 6, characterized in that, Controlling the actuator model to operate according to the execution strategy includes: When the execution strategy is empty, the actuator model is controlled not to perform braking operation; When the execution strategy is a partial braking strategy, the actuator model is controlled to perform braking operation according to the braking curve corresponding to the first deceleration; When the execution strategy is a full braking strategy, the actuator model is controlled to perform braking operation according to the braking curve corresponding to the second deceleration; the second deceleration is greater than the first deceleration.

8. The parameter calibration method according to claim 7, characterized in that, Controlling the actuator model to perform braking operations according to the braking curve corresponding to the first deceleration includes: The actuator model is controlled to obtain the braking curve corresponding to the first deceleration determined by the fitting method, and the braking operation is performed according to the braking curve.

9. A parameter calibration device for a brake system, characterized by include: The information acquisition module is used to calculate the vehicle operation information of the vehicle and the vehicle in front at the current moment through the vehicle kinematics model; The time calculation module is used to calculate the real-time collision time between the self-vehicle and the preceding vehicle based on the vehicle operation information of the self-vehicle and the preceding vehicle at the current moment. The braking control module is used to acquire the partial braking TTC threshold and the full braking TTC threshold, and based on the relationship between the real-time collision time, the partial braking TTC threshold and the full braking TTC threshold, determine the execution strategy of the actuator model, so as to control the actuator model to run according to the execution strategy; The threshold adjustment module is used to adjust the partial braking TTC threshold and the full braking TTC threshold based on the relative position of the vehicle and the vehicle in front when the vehicle is parked. The adjustment of the partial braking TTC threshold and the full braking TTC threshold based on the relative positions of the self-driving vehicle and the preceding vehicle when the self-driving vehicle is parked includes: Objective function ; wherein L is a reference relative position of the ego vehicle and the front vehicle when the ego vehicle is parked, and S is a relative position of the ego vehicle and the front vehicle when the ego vehicle is parked. Calculate the objective function value of the vehicle at the current parking time, and obtain the objective function values ​​of the vehicle at previous parking times; If the TTC threshold traversal is not completed, the partial braking TTC threshold and the full braking TTC threshold are dynamically adjusted according to the preset step size. If the TTC threshold traversal is complete, then the partial braking TTC threshold and the full braking TTC threshold corresponding to the minimum objective function value among the objective function values ​​of the vehicle at this parking time and the objective function values ​​of the historical parking times will be output.

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