阅读说明：本技术 一种进站控制方法及系统 (Inbound control method and system ) 是由 兑志魁 刘振楠 董海涛 何昊阳 于 2020-06-17 设计创作，主要内容包括：本发明涉及一种进站控制方法及系统,属于智能驾驶控制技术领域。其中方法包括：获取车辆的当前车速、以及车辆与站台的当前距离；确定分段制动过程中两个制动阶段对应的加速度；符合进站条件后,根据当前车速、当前距离以及每个制动阶段对应的加速度得到两个制动阶段切换时的拐点速度、以及各制动阶段的行驶距离；根据当前车速、各制动阶段的行驶距离以及各制动阶段的加速度得到车辆制动的分段速度曲线；以拐点速度为目标速度,平滑分段速度曲线,按照平滑后的速度曲线进行进站控制。本发明通过两个制动阶段进行减速进站提高了进站效率,降低了实际运营成本,并且对分段速度曲线的平滑提高了乘客的体验效果。(The invention relates to a station entering control method and a station entering control system, and belongs to the technical field of intelligent driving control. The method comprises the following steps: acquiring the current speed of the vehicle and the current distance between the vehicle and the platform; determining the corresponding acceleration of two braking stages in the segmented braking process; after the station entering condition is met, obtaining the inflection point speed when the two braking stages are switched and the running distance of each braking stage according to the current speed, the current distance and the acceleration corresponding to each braking stage; obtaining a sectional speed curve of vehicle braking according to the current vehicle speed, the driving distance of each braking stage and the acceleration of each braking stage; and smoothing the sectional speed curve by taking the inflection point speed as a target speed, and performing station entry control according to the smoothed speed curve. The invention improves the station entering efficiency by decelerating the station entering in two braking stages, reduces the actual operation cost, and improves the experience effect of passengers by smoothing the segmented speed curve.)

1. An inbound control method is characterized by comprising the following steps:

1) acquiring the current speed of the vehicle and the current distance between the vehicle and the platform; determining the acceleration corresponding to each braking stage in the segmented braking process; the segmented braking process comprises a first braking stage and a second braking stage;

2) after the station entering condition is met, obtaining the inflection point speed when the two braking stages are switched and the running distance of each braking stage according to the current speed, the current distance and the acceleration corresponding to each braking stage;

3) obtaining a sectional speed curve of vehicle braking according to the current vehicle speed, the driving distance of each braking stage and the acceleration of each braking stage;

4) and smoothing the segmented speed curve by taking the inflection point speed as a target speed, and performing station entry control according to the smoothed speed curve.

2. The inbound control method according to claim 1, wherein meeting the inbound condition comprises: the current estimated acceleration is greater than or equal to the reference acceleration; and the current estimated acceleration is obtained by calculation according to the current vehicle speed and the current distance.

3. The arrival control method according to claim 1 or 2, wherein the current distance between the vehicle and the station is obtained from vehicle position information obtained by a GPS positioning device and station position information calibrated in a map.

4. The station entry control method according to claim 1, wherein the calculation process of the inflection point velocity in the step 2) is:

wherein S is_{General assembly}When the station entering condition is met, the current distance between the vehicle and the platform is obtained; v. of_{Vehicle with wheels}When the station entering condition is met, the current speed of the vehicle is judged; a is₁Is the acceleration of the first braking phase; a is₂As a second braking stepAcceleration of the segment; v. of_{Inflection point}The inflection point speed when the first braking stage is switched to the second braking stage.

5. The inbound control method of claim 1, wherein the acceleration of the first braking phase is less than the acceleration of the second braking phase; smoothing the piecewise speed curve includes: and taking the inflection point speed as a target speed, increasing the acceleration in the first braking stage before the position corresponding to the inflection point speed, and adjusting the step length of the acceleration increase according to the difference between the actual speed and the target speed until the acceleration is increased to the acceleration in the second braking stage to finish the smoothing of the segmented speed curve.

6. An inbound control system comprises a vehicle speed detection device, a distance detection device and a braking device, and is characterized by further comprising a controller, wherein a signal input end of the controller is connected with the vehicle speed detection device and the distance detection device, a signal output end of the controller is connected with the braking device in a control mode, the controller comprises a processor, a memory and a computer program which is stored in the memory and can run on the processor, and the processor realizes the following steps when executing the computer program:

1) acquiring the current speed of the vehicle and the current distance between the vehicle and the platform; determining the acceleration corresponding to each braking stage in the segmented braking process; the segmented braking process comprises a first braking stage and a second braking stage;

2) after the station entering condition is met, obtaining the inflection point speed when the two braking stages are switched and the running distance of each braking stage according to the current speed, the current distance and the acceleration corresponding to each braking stage;

3) obtaining a sectional speed curve of vehicle braking according to the current vehicle speed, the driving distance of each braking stage and the acceleration of each braking stage;

4) and smoothing the segmented speed curve by taking the inflection point speed as a target speed, and performing station entry control according to the smoothed speed curve.

7. The inbound control system of claim 6, wherein meeting inbound conditions comprises: the current estimated acceleration is greater than or equal to the reference acceleration; and the current estimated acceleration is obtained by calculation according to the current vehicle speed and the current distance.

8. The system according to claim 6 or 7, wherein the distance detecting device comprises a GPS positioning device, and the current distance between the vehicle and the platform is obtained from the vehicle position information acquired by the GPS positioning device and the platform position information calibrated in the map.

9. The inbound control system according to claim 6, wherein the calculation process of the inflection point velocity in step 2) is:

wherein S is_{General assembly}When the station entering condition is met, the current distance between the vehicle and the platform is obtained; v. of_{Vehicle with wheels}When the station entering condition is met, the current speed of the vehicle is judged; a is₁Is the acceleration of the first braking phase; a is₂Is the acceleration of the second braking phase; v. of_{Inflection point}The inflection point speed when the first braking stage is switched to the second braking stage.

10. The inbound control system of claim 6 wherein the acceleration of the first braking phase is less than the acceleration of the second braking phase; smoothing the piecewise speed curve includes: and taking the inflection point speed as a target speed, increasing the acceleration in the first braking stage before the position corresponding to the inflection point speed, and adjusting the step length of the acceleration increase according to the difference between the actual speed and the target speed until the acceleration is increased to the acceleration in the second braking stage to finish the smoothing of the segmented speed curve.

Technical Field

The invention relates to a station entering control method and a station entering control system, and belongs to the technical field of intelligent driving control.

Background

At present, typical application scenarios of accurate stop at a station are fields such as high-speed rails and subways, however, the accurate stop technology cannot be applied to the bus stop technology with a complex environment due to the fact that the application scenarios include a special running track and a small chance of occurrence of obstacles.

In the field of automatic driving, an important research direction for safe driving is as follows: how to realize accurate parking at the barrier that appears in the driving process provides the technological basis for the accurate berth of bus. The platform is used as a virtual barrier, so that the bus can be accurately parked.

In the prior art, a trapezoidal speed planning method is generally adopted for planning the speed of a vehicle when an obstacle is encountered in an automatic driving process, for example: the journal is a journal article named as computer engineering, journal number 1000-3428(201)01-00-0 and named as a trapezoidal speed planning method of the intelligent vehicle based on the intermediate speed, wherein the basic principle of trapezoidal speed planning is that an obstacle is arranged at a position S away from the front of the vehicle, so that the intelligent vehicle needs to reduce the vehicle speed to 0 at the position S away from the front of the vehicle. When S is longer, the vehicle will be at an initial speed V_iAnd the system starts to pass through an acceleration section, a constant speed section and a deceleration section and finally stops at the point S at zero speed. The maximum speed set for the vehicle is V_maxIn the acceleration driving section, if the acceleration is too large, the tire can slip or the riding comfort is influenced, so the maximum allowable acceleration is limited; during the deceleration driving phase, the maximum acceleration is also set to ensure the comfort of the ride.

In the article, although the accurate parking of the vehicle when meeting the obstacle is realized, the problem of long arrival time is brought to the condition that the bus arrival speed is relatively low and is relatively far away from the station by adopting the uniform deceleration model with trapezoidal speed planning, the arrival efficiency is seriously influenced, and poor user experience is brought.

Disclosure of Invention

The application aims to provide a method for controlling the inbound, which is used for solving the problem of poor experience of the existing inbound control; meanwhile, a station-entering control system is also provided to solve the problem of poor experience of the existing station-entering control.

In order to achieve the above object, the present application provides a technical solution of an inbound control method, including the following steps:

1) acquiring the current speed of the vehicle and the current distance between the vehicle and the platform; determining the acceleration corresponding to each braking stage in the segmented braking process; the segmented braking process comprises a first braking stage and a second braking stage;

2) after the station entering condition is met, obtaining the inflection point speed when the two braking stages are switched and the running distance of each braking stage according to the current speed, the current distance and the acceleration corresponding to each braking stage;

3) obtaining a sectional speed curve of vehicle braking according to the current vehicle speed, the driving distance of each braking stage and the acceleration of each braking stage;

4) and smoothing the segmented speed curve by taking the inflection point speed as a target speed, and performing station entry control according to the smoothed speed curve.

The technical scheme of the inbound control method has the beneficial effects that: after the station entering condition is met, the braking process is divided into two braking stages, different accelerated speeds are adopted for deceleration in each braking stage, after the vehicle speed and the distance which meet the station entering condition and the accelerated speed of each braking stage are obtained, a segmented speed curve can be drawn, an obvious slope change point exists in the speed curve at the moment, namely the accelerated speed of the first braking stage is suddenly changed into the accelerated speed of the second braking stage, the segmented speed curve is smoothed according to the speed of the point, the suddenly changed point is smoothed, and control is performed according to the smoothed speed curve. The invention improves the station entering efficiency by decelerating the station entering in two braking stages, reduces the actual operation cost, and improves the experience effect of passengers by smoothing the segmented speed curve.

Further, in order to meet the requirement of the inbound comfort, meeting the inbound condition comprises: the current estimated acceleration is greater than or equal to the reference acceleration; and the current estimated acceleration is obtained by calculation according to the current vehicle speed and the current distance.

Further, in order to more accurately obtain the distance between the vehicle and the platform, the current distance between the vehicle and the platform is obtained through vehicle position information acquired by the GPS positioning device and platform position information calibrated in a map.

Further, the calculation process of the inflection point velocity in the step 2) is as follows:

wherein S is_{General assembly}When the station entering condition is met, the current distance between the vehicle and the platform is obtained; v. of_{Vehicle with wheels}When the station entering condition is met, the current speed of the vehicle is judged; a is₁Is the acceleration of the first braking phase; a is₂Is the acceleration of the second braking phase; v. of_{Inflection point}The inflection point speed when the first braking stage is switched to the second braking stage.

Further, in order to improve the stability and embody the effect of the braking process, the acceleration of the first braking stage is smaller than the acceleration of the second braking stage; smoothing the piecewise speed curve includes: and taking the inflection point speed as a target speed, increasing the acceleration in the first braking stage before the position corresponding to the inflection point speed, and adjusting the step length of the acceleration increase according to the difference between the actual speed and the target speed until the acceleration is increased to the acceleration in the second braking stage to finish the smoothing of the segmented speed curve.

In addition, this application still provides a technical scheme of control system that arrives at a station, including speed of a motor vehicle detection device, distance detection device and arresting gear, still include the controller, the signal input part of controller connects speed of a motor vehicle detection device and distance detection device, and the signal output part control of controller connects arresting gear, and the controller includes treater, memory and the computer program of storing in the memory and can be run on the treater, the treater realizes following step when carrying out the computer program:

1) acquiring the current speed of the vehicle and the current distance between the vehicle and the platform; determining the acceleration corresponding to each braking stage in the segmented braking process; the segmented braking process comprises a first braking stage and a second braking stage;

2) after the station entering condition is met, obtaining the inflection point speed when the two braking stages are switched and the running distance of each braking stage according to the current speed, the current distance and the acceleration corresponding to each braking stage;

3) obtaining a sectional speed curve of vehicle braking according to the current vehicle speed, the driving distance of each braking stage and the acceleration of each braking stage;

4) and smoothing the segmented speed curve by taking the inflection point speed as a target speed, and performing station entry control according to the smoothed speed curve.

The technical scheme of the inbound control system has the advantages that: after the station entering condition is met, the braking process is firstly divided into two braking stages, different accelerated speeds are adopted for deceleration in each braking stage, after the vehicle speed meeting the station entering condition is obtained through the vehicle speed detection device, the distance is obtained through the distance detection device, and the accelerated speed of each braking stage is obtained, the controller can draw a segmented speed curve, an obvious slope change point exists in the speed curve at the moment, namely the accelerated speed of the first braking stage is suddenly changed into the accelerated speed of the second braking stage, the segmented speed curve is smoothed according to the speed of the point, the suddenly changed point is smoothed, and the controller controls the braking device according to the smoothed speed curve. The invention improves the station entering efficiency by decelerating the station entering in two braking stages, reduces the actual operation cost, and improves the experience effect of passengers by smoothing the segmented speed curve.

Further, in order to meet the requirement of the inbound comfort, meeting the inbound condition comprises: the current estimated acceleration is greater than or equal to the reference acceleration; and the current estimated acceleration is obtained by calculation according to the current vehicle speed and the current distance.

Further, in order to more accurately obtain the distance between the vehicle and the platform, the distance detection device comprises a GPS positioning device, and the current distance between the vehicle and the platform is obtained through vehicle position information acquired by the GPS positioning device and platform position information calibrated in a map.

Further, the calculation process of the inflection point velocity in the step 2) is as follows:

wherein S is_{General assembly}When the station entering condition is met, the current distance between the vehicle and the platform is obtained; v. of_{Vehicle with wheels}When the station entering condition is met, the current speed of the vehicle is judged; a is₁Is the acceleration of the first braking phase; a is₂Is the acceleration of the second braking phase; v. of_{Inflection point}The inflection point speed when the first braking stage is switched to the second braking stage.

Further, in order to improve the stability and embody the effect of the braking process, the acceleration of the first braking stage is smaller than the acceleration of the second braking stage; smoothing the piecewise speed curve includes: and taking the inflection point speed as a target speed, increasing the acceleration in the first braking stage before the position corresponding to the inflection point speed, and adjusting the step length of the acceleration increase according to the difference between the actual speed and the target speed until the acceleration is increased to the acceleration in the second braking stage to finish the smoothing of the segmented speed curve.

Drawings

FIG. 1 is a schematic diagram of the inbound control system of the present invention;

FIG. 2 is a schematic diagram of the inbound control method of the present invention;

FIG. 3 is a schematic illustration of a vehicle of the present invention entering a station;

FIG. 4 is a schematic illustration of the segmented braking of the present invention;

in the figure: 1 is an automatic driving vehicle, 2 is a lane line, 3 is a platform target point, and 4 is a platform.

Detailed Description

With respect to the system:

the station entering control system comprises a vehicle speed sensor, a GPS positioning device, an acceleration sensor, a display device, a braking device and a controller, as shown in figure 1; the vehicle speed sensor, the GPS positioning device, the acceleration sensor, the display device and the braking device are all connected with the controller.

The vehicle speed sensor is used as vehicle speed detection device for detecting the vehicle speed of the automatic driving vehicle; a GPS positioning device for detecting position information of the autonomous vehicle; an acceleration sensor for detecting a response acceleration of the autonomous vehicle; the display device is an instrument display system and is used for displaying the inbound identifiers and the icons; the braking device is used for executing a braking program; the controller comprises a processor, a memory in which a map and a computer program executable on the processor are stored, the processor implementing the inbound control method when executing the computer program.

The map stored in the memory is a high-precision map, and the controller needs to finish the marking of the station in the high-precision map before executing the station entering control method; and three acceleration empirical values need to be calibrated, which are respectively: reference acceleration a_{Reference to}First acceleration a₁And a second acceleration a₂. In order to improve the experience effect of passengers, the first acceleration a₁< second acceleration a₂. The calibrated three accelerations are different due to the difference of different automatic driving vehicle parameters, and the reference acceleration a_{Reference to}For the requirement of comfortable station entrance, the three acceleration empirical values are determined by acquiring the operation of a driver for stopping at a fixed station and analyzing data in combination with the subjective feelings of vehicle passengers, so that the station entrance control method achieves the purposes of personification and comfortable station entrance.

As to the method:

specifically, the flow of the inbound control method may be implemented by computer program instructions, and the controller stores the computer program instructions formed by implementing the inbound control method, and the inbound control method is shown in fig. 2, and includes the following steps:

1) the controller acquires the speed information of the automatic driving vehicle (namely the vehicle) through the speed sensor, acquires the position information of the automatic driving vehicle through the GPS positioning device, and compares the position information with the platform position calibrated on the high-precision map to obtain the distance information between the automatic driving vehicle and the platform.

2) Judging whether the automatic driving vehicle meets the station entering condition or not according to the vehicle speed information and the distance information in the step 1), and planning the station entering track of the automatic driving vehicle after the automatic driving vehicle meets the station entering condition.

In this step, the calculated current estimated acceleration a is satisfied with the inbound condition_tNot less than reference acceleration a_{Reference to}(the acceleration referred to here is actually the absolute value of the acceleration), the current estimated acceleration a_tIn order to automatically drive the current distance between the vehicle and the platform, the current vehicle speed is used as the initial speed, and the vehicle speed stopping at the platform is the acceleration when the final speed is 0, the specific calculation formula is as follows:

wherein v is_tA current vehicle speed for the autonomous vehicle; s_tIs the current distance of the autonomous vehicle from the platform.

That is, a_t≥a_{Reference to}According with the condition of comfortable station-entering, planning the station-entering track and executing the step 3), a) as shown in figure 3_t＜a_{Reference to}And in the process, cruising is carried out according to the set road track, the current vehicle speed is kept to be driven at a constant speed, and no braking operation is adopted. In fig. 3, the autonomous vehicle 1 travels straight along the lane line 2 and decelerates to the platform target point 3 to stop the platform 4, the solid line frame is the position of the autonomous vehicle 1 when starting the station entering condition, and the dashed line frame is the position of the autonomous vehicle 1 when stopping.

3) And after planning the arrival track, planning a segmented speed curve of the automatic driving vehicle 1 according to the speed information and the distance information in the step 1) and the calibrated acceleration empirical value.

In this step, the automatic driving vehicle 1 is controlled in a segmented braking mode and is divided into two braking stages, wherein the first braking stage adopts a first acceleration a with smaller acceleration₁I.e. the acceleration of the first braking phase is a₁The second stage adopts the second acceleration a with larger acceleration₂I.e. the acceleration of the second braking phase is a₂The segmentation principle is shown in FIG. 4, and v is satisfied under the inbound condition_t＝v_{Vehicle with wheels}，S_t＝S_{General assembly}＝S₁+S₂According to physics, the following can be known:

wherein S is₁Is a first acceleration a₁Down braking distance (braking distance, i.e. travel distance); s₂At a second acceleration a₂A lower braking distance; s_{General assembly}When the station entering condition is met, automatically driving the current distance between the vehicle 1 and the platform 4; v. of_{Vehicle with wheels}When the arrival conditions are met, automatically driving the current speed of the vehicle 1; v. of_{Inflection point}Is a first acceleration a₁And a second acceleration a₂The intermediate vehicle speed during switching, that is, the inflection point speed during switching from the first braking stage to the second braking stage.

Further obtaining:according to the obtained v_{Inflection point}Can calculate S₁And S₂The size of (2).

v_{Inflection point}、S₁、S₂、v_{Vehicle with wheels}、a₁、a₂It is known that, in determining the distance accuracy step of a plan, the following formula is used:

wherein v is_{Next point}The speed of the next point in the planned inbound track is calculated; v. of_{Current point of current}The speed of the current point in the planned inbound track is obtained; a is_PlanningAcceleration planned for different phases, where the first phase corresponds to a₁The second stage corresponds to a₂；S_{Precision step length}The distance precision step length for planning.

Further, the speeds of the automatic driving vehicle 1 at different distance points can be obtained, a segmented speed curve is obtained, the planned speed is planned according to a uniform deceleration model, the planned speed curve is a curve segment of a broken line, and a catastrophe point of slope change corresponds to an inflection point speed v_{Inflection point}From the planned curve by finding the discontinuities of the slope changeAnd searching a speed planning inflection point. Of course, since the planned vehicle speed has no negative value, it is necessary to determine the value of the lower square before calculating the speed of the next point, and if the value is negative, the speed of the next point is 0.

4) Velocity v at knee point_{Inflection point}And (3) smoothing the segmented speed curve planned in the step 3) for the target speed, and reducing the impact caused by sudden acceleration change in the deceleration process.

Smoothing the velocity curve corresponding to the inflection point by applying a sudden acceleration (a)₁-a₂) Performing smoothing, specifically comprising: when the position corresponding to the inflection point is approached, the acceleration is increased, the step length of the acceleration is delta a, namely the current acceleration after the acceleration is increased is a₁+ Δ a, and then determining the actual speed, if the difference between the actual speed and the required inflection point speed is large, increasing the acceleration step length, and if the difference is small, appropriately decreasing the acceleration step length. The effect is that the acceleration will not generate sudden change, but will gradually increase to reach a₂The inflection point velocity meets the requirement, thereby realizing smooth acceleration transition.

The acceleration sensor is used for acquiring the actual response acceleration of the vehicle in the acceleration increasing process, and whether the acceleration is increased in place or not is judged according to the actual response acceleration of the vehicle.

5) And (4) controlling a braking device (a dynamic braking actuator) by the controller according to the speed curve smoothed in the step 4), and automatically opening the door when the automatically-driven vehicle 1 enters the station and stops.

In the process of braking, information such as the station entering identification, the icon, the lane line 2 and the like is displayed through the instrument display system.

In the above embodiment, the basis for determining whether the entering condition is satisfied is the current estimated acceleration, so that the entering process has comfort, and as another embodiment, the basis for determining whether the entering condition is satisfied may also be the distance between the autonomous vehicle 1 and the platform 4, and when the distance between the autonomous vehicle 1 and the platform 4 is less than a predetermined distance, the entering condition is satisfied, and a path and a speed curve are planned.

In the above embodiment, after the arrival conditions are met, the arrival path needs to be planned, and as another embodiment, the arrival path may not need to be planned even when the path of the autonomous vehicle 1 is fixed and is preset in advance.

In the above embodiment, the distance between the autonomous vehicle 1 and the platform 4 is obtained by comparing the position information of the autonomous vehicle 1 obtained by the GPS positioning device with the platform position calibrated in the high-precision map, and as another embodiment, the distance information may also be obtained by a device such as a laser radar or an infrared sensor, and the present invention is not limited thereto.

In the above embodiment, the braking process is to decelerate the autonomous vehicle 1 with a small acceleration, and then to decelerate with a smooth transition to a large acceleration until the autonomous vehicle 1 stops, as another embodiment, the braking process may also be to decelerate with a large acceleration, and then to decelerate with a smooth transition to a small acceleration, that is, a₁＜a₂And the smoothness of the segmented speed curve is finished by reducing the acceleration, so that the stability in the braking process is ensured.

In the step of smoothing the piecewise velocity curve, it is preferable to adjust the step length of the acceleration with the inflection point velocity as the target velocity, but as another embodiment, the step length of the acceleration increase may be adjusted by obtaining the target acceleration from the inflection point velocity and the current vehicle speed and using the difference between the actual acceleration and the target acceleration, or a may be directly set₁To a₂The process of variation of (c).

According to the invention, the experience values of the acceleration are obtained by referring to the operation of an actual driver and analyzing in combination with the data subjective by passengers, so that the whole braking process is more anthropomorphic, the purpose of anthropomorphic and comfortable arrival is achieved, and the experience effect of a user is improved. And the whole process is divided into two braking stages, so that the braking efficiency is improved and the vehicle operation cost is reduced under the conditions of far distance from a station and low vehicle speed.