Bus slow braking simulation system and method

Abstract

The invention discloses a bus slow braking simulation system and method. The system comprises a parameter input module, a simulation calculation module and a data recording and visualization module. The parameter input module is used for inputting scene parameters and simulation parameters by technicians; the simulation calculation module performs slow braking simulation based on the scene parameters and the simulation parameters to obtain a slow braking strategy; and the data recording and visualization module is used for carrying out data recording and visualization display on the slow braking simulation result. The bus slow braking simulation system provided by the invention can be used by bus auxiliary driving research and development personnel, is used for simulating a slow braking strategy of a collision slow braking scene, and can simulate different slow braking strategies based on different simulation parameters according to scene parameters such as an initial distance and expected safe braking time; through visual display for comparison by technicians, different slow braking strategies provided by simulation can also be used for training data of the bus auxiliary driving artificial intelligence model.

Description

Technical Field

[0001] The present application provides a bus slow braking simulation system and method, which relate to the technical field of bus assisted driving. Background Art

[0002] The collision mitigation braking system is a safety technology system used to assist driving, predict collisions, and actively prevent them. It uses microwave radar and / or a monocular camera to sense and identify vehicles ahead, oncoming vehicles, and pedestrians. When there is a risk of collision with a vehicle or pedestrian, the system reminds the driver to take evasive measures through a warning sound and instrument panel display. When the vehicle ahead and pedestrians are closer, the system applies slight braking to remind the driver to operate the vehicle again in a somatosensory manner. When the vehicle approaches further, the system will apply strong braking to assist the driver in avoiding collision and reducing injuries.

[0003] Applying assisted driving to special vehicles such as buses requires targeted solutions to problems in special scenarios. For example, in addition to achieving active braking, the collision mitigation braking system also needs to achieve slow braking. This is because when a bus brakes, both external and internal safety need to be considered. Most passengers on the bus are not wearing seat belts or are standing, so the bus braking needs to achieve a slow braking effect.

[0004] How to simulate slow braking for bus braking scenarios has become a technical problem that needs to be solved urgently in this field of technology. Summary of the Invention

[0005] The technical problem to be solved by this application is how to perform slow braking simulation for bus braking scenarios.

[0006] In order to solve the above technical problems, the technical solution of the present application provides a bus braking simulation system, including a parameter input module, a simulation calculation module and a data recording and visualization module; the parameter input module is used by technicians to input scene parameters and simulation parameters; the simulation calculation module performs braking simulation based on the scene parameters and simulation parameters to obtain a braking strategy; the data recording and visualization module is used to record and visualize the braking simulation results.

[0007] Preferably, the scene parameters include:

[0008] Initial distance L, the initial distance between the vehicle and the obstacle;

[0009] Initial speed V0, initial speed of the vehicle;

[0010] Expected braking time TE, expected safe braking time;

[0011] Base acceleration as, the base value of braking deceleration.

[0012] Preferably, the simulation parameters include:

[0013] PID parameters, including proportional, integral, and differential coefficients;

[0014] Simulation time TS, the total time of simulation.

[0015] Preferably, the simulation calculation module simulates the vehicle braking process and advances the simulation time simulation cycle with a fixed time step dt, specifically including the following steps:

[0016] S1 calculates the desired speed Ve, and the maximum safe speed currently allowed is calculated based on the remaining distance Dt and the safety distance S, which is the desired speed. The calculation formula is: Ve = (Dt-S) / TE;

[0017] S2 PID control intervenes. When the vehicle speed Vt exceeds the desired speed Ve, PID control is activated to adjust the braking coefficient. PID calculates the braking coefficient, using the error et between the vehicle speed Vt and the desired speed Ve as the input of PID control to calculate the braking coefficient Fc. The output Fc is limited to the range [0,1].

[0018] S3 updates the physical model:

[0019] The remaining distance decreases, Dt = Dt - Vt * dt;

[0020] The vehicle speed decreases, Vt = Vt-at*dt;

[0021] Expected braking time reduction, TE = TE-dt;

[0022] S4 termination condition:

[0023] Termination condition 1: The loop ends when the vehicle speed Vt is lower than the set threshold;

[0024] Termination condition 2: The loop ends when the remaining distance Dt is less than the safety distance S;

[0025] If either the first or second termination condition is met, the loop ends.

[0026] Preferably, the data recording and visualization module is used to store data changes of all variables and display them through visualization.

[0027] Furthermore, the data recording and visualization module includes a log submodule for recording vehicle speed, braking coefficient, speed error, and remaining distance data at each time step.

[0028] Furthermore, the data recording and visualization module includes a chart visualization display submodule, and the chart visualization display submodule includes a braking coefficient-time chart display; a vehicle speed-time chart display; a remaining distance-time chart display; and a PID parameter-time chart display.

[0029] The present application also provides a bus slow braking simulation method, which uses the aforementioned bus slow braking simulation system to perform bus slow braking simulation.

[0030] The present application also provides an electronic device, comprising: a memory and a processor; the memory is used to store a computer program; the processor is used to execute the computer program to implement the aforementioned bus slow braking simulation method.

[0031] The present application also provides a computer-readable storage medium for storing a computer program, which implements the aforementioned bus slow braking simulation method when executed.

[0032] The bus braking simulation system provided in this application can be used by bus assisted driving R&D personnel to simulate the braking strategy of collision mitigation braking scenarios. According to scenario parameters such as initial distance and expected safe braking time, different braking strategies can be simulated based on different simulation parameters. Through intuitive display for comparison by technical personnel, the different braking strategies provided by the simulation can also be used as training data for bus assisted driving artificial intelligence models. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 This is an architecture diagram of a bus slow braking simulation system provided in an embodiment of the present application;

[0034] Figure 2 Schematic diagram of the vehicle braking process simulated by the simulation calculation module. DETAILED DESCRIPTION

[0035] To make the present application more obvious and easy to understand, various exemplary embodiments will be introduced below. These examples are non-limiting, and it should be understood that they are used to illustrate the broader application aspects of the device, system and method. Without departing from the essence and scope of the present application, these embodiments can be subjected to various changes and can be replaced by equivalents. In addition, various changes can be carried out to adapt to the purpose, content or scope of the present application in order to adapt to special circumstances, materials, material components, treatment types, treatment actions or steps. All of these changes will be within the scope of protection of the present application.

[0036] Any materials, dimensions, or quantities described in the overview or detailed description are intended to be examples only and are not intended to limit the subject matter of this application. Furthermore, the various implementations of the embodiments described herein are intended to complement each other, rather than to replace each other, unless otherwise indicated. In other words, implementations from one embodiment can be freely combined with implementations from other embodiments, as those skilled in the art will readily appreciate, unless otherwise indicated.

[0037] In the description of this application, it should be noted that the terms "inner" and "outer" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, or the orientations or positional relationships in which the product of this application is typically placed when in use. These terms are intended solely to facilitate the description of this application and simplify the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, be constructed, or operate in a specific orientation. Therefore, they should not be construed as limitations on this application. Furthermore, the terms "first" and "second" and the like are used solely for distinction and should not be construed as indicating or implying relative importance.

[0038] It should also be noted that, in the description of this application, unless otherwise expressly specified or limited, the terms "disposed" and "connected" should be understood in a broad sense. For example, they can refer to fixed connections, detachable connections, or integral connections; they can refer to direct connections, indirect connections through an intermediate medium, or internal connections between two components. Those skilled in the art will understand the specific meanings of the above terms in this application based on the specific circumstances.

[0039] Example

[0040] The bus braking simulation system provided in the embodiment of the present application is provided for use by bus assisted driving R&D personnel to simulate the braking strategy of the collision mitigation braking scenario. According to the scene parameters such as the initial distance and the expected safe braking time, different braking strategies can be simulated based on different simulation parameters, which can be used for intuitive comparison by R&D personnel. The different braking strategies provided by the simulation can also be used as training data for the bus assisted driving artificial intelligence model.

[0041] In one embodiment, the bus slow braking simulation system provided by the embodiment of the present application is as follows: Figure 1 , including a parameter input module, a simulation calculation module and a data recording and visualization module; the parameter input module is used by technicians to input scene parameters and simulation parameters; the simulation calculation module performs braking simulation based on the scene parameters and simulation parameters to obtain a braking strategy; the data recording and visualization module is used to record and visualize the braking simulation results.

[0042] The simulation calculation module simulates the vehicle braking process, converting the braking time into a safe speed target. It uses PID closed-loop control to adjust the braking coefficient in real time to ensure that the vehicle stops within the set time and maintains a safe distance. The physical model also simulates the vehicle deceleration process, where the braking coefficient affects the deceleration, which in turn affects changes in speed and distance. The simulation calculation module adjusts the braking force based on the error between the vehicle speed and the desired speed, allowing the system to stabilize in the desired state as quickly as possible. The data recording and visualization module integrates multi-dimensional visualization to simultaneously plot the braking coefficient, speed, distance, and PID component curves, intuitively displaying and analyzing the control process. It visually resolves problems encountered when adjusting PID parameters, such as oscillation or slow convergence, or unexpected braking distance. It also addresses whether the control logic is correct, the error calculation is reasonable, the integral term is correctly accumulated, and the differential term handles the rate of change.

[0043] In a further embodiment,

[0044] The scene parameters include:

[0045] Initial distance L, the initial distance between the vehicle and the obstacle;

[0046] Initial speed V0, initial speed of the vehicle;

[0047] Expected braking time TE, expected safe braking time;

[0048] Base acceleration as, the base value of braking deceleration.

[0049] The simulation parameters include:

[0050] PID parameters, including proportional, integral, and differential coefficients;

[0051] Simulation time TS, the total time of simulation.

[0052] In a further embodiment, the simulation calculation module simulates the vehicle braking process, advances the simulation time simulation cycle with a fixed time step dt, see Figure 2 , specifically including the following steps:

[0053] S1 calculates the expected speed Ve, and calculates the current maximum allowed safe speed based on the remaining distance Dt and the safety distance S (1.5 meters), which is the expected speed. The calculation formula is: Ve = (Dt-S) / TE.

[0054] S2 PID control intervenes. When the vehicle speed Vt (initially V0) exceeds the desired speed Ve, PID control is started to adjust the braking coefficient. PID calculates the braking coefficient, using the error et between the vehicle speed Vt and the desired speed Ve as the input of PID control to calculate the braking coefficient Fc. The output Fc is limited to the range [0,1].

[0055] For example, in the embodiment of the present application, the calculation formula of PID control is Fc=Kp*et+Ki*∑et*dt+Kd*det / dt, wherein Kp, Ki and Kd are proportional, integral and differential coefficients respectively, which together constitute PID parameters, which are set by technicians before simulation. Different simulation results can be obtained by different PID parameters.

[0056] It can be understood that the actual braking deceleration at = Fc*as, the reference acceleration as is related to the specific vehicle braking system, and can be understood as the maximum braking deceleration that the vehicle braking system can produce. The braking coefficient Fc is used to measure the actual working state of the braking system, such as the braking force, and at = Fc*as is the actual braking deceleration generated by the braking system.

[0057] S3 updates the physical model:

[0058] The remaining distance decreases, Dt = Dt - Vt * dt;

[0059] The vehicle speed decreases, Vt = Vt-at*dt;

[0060] Expected braking time reduction, TE = TE-dt;

[0061] From this we can see that the greater the braking coefficient, the greater the deceleration and the faster the vehicle stops.

[0062] S4 termination condition:

[0063] Termination condition 1: The loop ends when the vehicle speed Vt is lower than the set threshold (set a small value), and the vehicle is considered to have stopped, avoiding unrealistic situations such as negative speed;

[0064] Termination condition 2: When the remaining distance Dt is less than the safety distance S, the loop ends and the vehicle is considered to have failed to brake.

[0065] If either the first or second termination condition is met, the loop ends.

[0066] The simulation module provided in the embodiments of the present application simulates the vehicle braking process by advancing the simulation cycle with a fixed time step dt. During the simulation, PID feedback is used to control the vehicle speed to a desired speed, avoiding strong braking to soften the braking curve. The overall concept is to mimic the braking process of a person. After identifying an obstacle, the user first applies a light brake, then gradually applies a deeper brake as the distance and speed decrease. When the distance and speed decrease to a safe state, the user slowly releases the brake, reducing the braking force. At the end of the braking process, the vehicle speed slowly decreases, achieving a gentle braking effect.

[0067] It is understandable that the expected speed is affected by the set expected braking time. When using the bus slow braking simulation system, technicians can adjust the slow braking simulation by setting different expected braking times, so as to observe the slow braking simulation results under different expected braking times.

[0068] In a further embodiment, the data recording and visualization module is used to store data changes of all variables and display them visually, specifically including:

[0069] The log submodule is used to record detailed data such as vehicle speed, braking coefficient, speed error, remaining distance, PID parameters, etc. at each time step.

[0070] The chart visualization sub-module includes a braking coefficient-time chart display, which reflects the dynamic adjustment of the braking force; a vehicle speed-time chart display: showing the vehicle speed reduction process; a remaining distance-time chart display: showing the change in the distance between the vehicle and the obstacle; and a PID parameter-time chart display, which respectively represents the contributions of the P, I, and D components.

[0071] The bus slow braking simulation system provided in the embodiment of the present application allows technicians to simulate the slow braking strategy of the collision mitigation braking scenario by setting simulation parameters and initial scenario parameters. Technicians can adjust various parameters such as initial distance, initial speed, expected safe braking time, baseline acceleration, PID parameters, etc. according to simulation requirements to obtain different slow braking strategies. The bus slow braking simulation system provided in the embodiment of the present application provides an intuitive graphical display for R&D personnel to visually compare. The detailed data stored in the log submodule can also be used as training data for the bus assisted driving artificial intelligence model.

[0072] The embodiment of the present application also provides a bus slow braking simulation method, which uses the aforementioned bus slow braking simulation system to perform bus slow braking simulation.

[0073] It can be understood that the implementation of the bus braking simulation system provided in the embodiment of the present application relies on computer programs to deploy or instruct corresponding hardware such as storage devices, processors, and display screens to complete it. After reading and understanding all or part of the processes executed by the bus braking simulation system provided in the embodiment of the present application, ordinary technicians in this field can easily implement it through computer programs. There are no technical barriers for ordinary technicians in this field and no creative work is required.

[0074] The present application also provides a computer program product or computer program, which includes computer instructions stored in a computer-readable storage medium. A processor of an electronic device reads the computer instructions from the computer-readable storage medium and, when executing the computer instructions, implements the bus slow braking simulation system and bus slow braking simulation method provided in the present application.

[0075] An embodiment of the present application also provides an electronic device, specifically including: a processor and a memory, wherein the memory is used to store a computer program, and the computer program is loaded and executed by the processor to implement a bus slow braking simulation system and a bus slow braking simulation method.

[0076] The above description is only a preferred embodiment of the present application and does not limit the present application in any form or substance. It should be pointed out that ordinary technicians in this technical field can make several improvements and supplements without departing from the present application, and these improvements and supplements should also be regarded as the scope of protection of the present application. Any technician familiar with this profession can make some changes, modifications and equivalent changes made by using the technical content disclosed above without departing from the content and scope of the present application, which are all equivalent embodiments of the present application; at the same time, any equivalent changes, modifications and evolutions made to the above-mentioned embodiments based on the essential technology of the present application are still within the scope of the technical solution of the present application.

Claims

1. A bus slow braking simulation system, characterized in that: It includes a parameter input module, a simulation calculation module and a data recording and visualization module; the parameter input module is used by technicians to input scene parameters and simulation parameters; the simulation calculation module performs braking simulation based on the scene parameters and simulation parameters to obtain the braking strategy; the data recording and visualization module is used to record and visualize the braking simulation results.

2. A bus slow braking simulation system according to claim 1, characterized in that: The scene parameters include: Initial distance L, the initial distance between the vehicle and the obstacle; Initial speed V0, initial speed of the vehicle; Expected braking time TE, expected safe braking time; Base acceleration as, the base value of braking deceleration.

3. A bus slow braking simulation system according to claim 2, characterized in that: The simulation parameters include: PID parameters, including proportional, integral, and differential coefficients; Simulation time TS, the total time of simulation.

4. A bus slow braking simulation system according to claim 3, characterized in that: The simulation calculation module simulates the vehicle braking process and advances the simulation time simulation cycle with a fixed time step dt, specifically including the following steps: S1 calculates the desired speed Ve, and the maximum allowed safe speed is calculated based on the remaining distance Dt and the safety distance S, which is the desired speed. The calculation formula is: Ve = (Dt-S) / TE; S2 PID control intervenes. When the vehicle speed Vt exceeds the desired speed Ve, PID control is activated to adjust the braking coefficient. PID calculates the braking coefficient, using the error et between the vehicle speed Vt and the desired speed Ve as the input of PID control to calculate the braking coefficient Fc. The output Fc is limited to the range [0,1]. S3 updates the physical model: The remaining distance decreases, Dt = Dt - Vt * dt; The vehicle speed decreases, Vt = Vt-at*dt; Expected braking time reduction, TE = TE-dt; S4 termination condition: Termination condition 1: The loop ends when the vehicle speed Vt is lower than the set threshold; Termination condition 2: The loop ends when the remaining distance Dt is less than the safety distance S; If either the first or second termination condition is met, the loop ends.

5. A bus slow braking simulation system according to claim 1, characterized in that: The data recording and visualization module is used to store data changes of all variables and display them through visualization.

6. A bus slow braking simulation system according to claim 5, characterized in that: The data recording and visualization module includes a log submodule for recording vehicle speed, braking coefficient, speed error, and remaining distance data at each time step.

7. A bus slow braking simulation system according to claim 5, characterized in that: The data recording and visualization module includes a chart visualization display submodule, and the chart visualization display submodule includes a braking coefficient-time chart display; a vehicle speed-time chart display; a remaining distance-time chart display; and a PID parameter-time chart display.

8. A bus slow braking simulation method, characterized in that: The bus slow braking simulation system according to any one of claims 1 to 7 is used to perform bus slow braking simulation.

9. An electronic device, characterized in that: include: memory and processor; The memory is used to store computer programs; The processor is configured to execute the computer program to implement the bus slow braking simulation method according to claim 8.

10. A computer-readable storage medium, characterized in that Used to store a computer program, which, when executed, implements the bus slow braking simulation method according to claim 8.

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