WO2020062844A1

WO2020062844A1 - Method for calculating vehicle-mounted speed curve for avoiding emergency triggering

Info

Publication number: WO2020062844A1
Application number: PCT/CN2019/083373
Authority: WO
Inventors: 刘栋青; 沙硕; 孙野; 孙可; 沈涛; 张韦
Original assignee: 湖南中车时代通信信号有限公司
Priority date: 2018-09-28
Filing date: 2019-04-19
Publication date: 2020-04-02
Also published as: CN109283929A

Abstract

A method for calculating a deceleration curve of a train, comprising: establishing a deceleration model according to an input (102), the input comprising ground equipment-related input information and train-related input information, and the deceleration model comprising a plurality of speed-deceleration corresponding segments; determining a characteristic point of a second-order Bézier curve for the segment corresponding to the present speed (104); and calculating the second-order Bézier curve as a deceleration curve based on the determined characteristic point (106).

Description

Calculation method of vehicle speed curve to avoid triggering emergency

Technical field

The invention relates to the field of train operation control systems, and in particular, to a method for calculating an on-vehicle speed curve of an on-board ATP (Automatic Train) system of a train control system to avoid triggering an emergency stop.

Background technique

Train automatic driving system (Automatic Train Operation) (ATO), its main function is to use the on-board and ground information to automatically control the train's operation, to achieve automatic adjustment of the train's running speed and maintain the best operating state, complete timing, fixed-point parking, automatic Functions such as door opening and closing control can reduce the labor intensity of the driver and maximize energy savings. With the development of China's rail transit industry, ATO has been widely used in urban rail transit, intercity rail transit signal systems and other fields, and its importance has become increasingly prominent, especially with higher requirements for system safety, reliability and availability. .

"High Speed Train Speed Monitoring Curve Research" (ISSN: 1673-4440 CN: 11-5423 / U, "Railway Communication Signal Engineering Technology" Magazine, December 2014) describes some researches on high speed train speed monitoring curves, however The problem in this article is that the generated curve is not smooth enough, which may cause excessive brake wear during the deceleration of the train.

Summary of the Invention

This summary is provided to introduce a selection of concepts in a simplified form that are further described below in the Detailed Description. This summary is not intended to identify key features or essential features of the claimed subject matter, nor is it intended to be used as an aid in determining the scope of the claimed subject matter.

According to an embodiment of the present invention, a method for calculating a deceleration curve of a train is provided. The method includes:

Establishing a deceleration model based on inputs, the inputs including ground equipment related input information and train related input information, the deceleration model including multiple speed-deceleration corresponding segments;

Determine the characteristic points of the second-order Bézier curve for the segment corresponding to the current speed; and

A second-order Bézier curve is calculated as the deceleration curve based on the determined feature points.

According to another embodiment of the present invention, an automatic train protection device is also provided, including:

An input interface for receiving input information from an external device, the input including ground device-related input information and train-related input information;

A processor configured to:

Establishing a deceleration model according to the input, the deceleration model including a plurality of speed-deceleration corresponding segments;

Determine the characteristic points of the second-order Bézier curve for the segment corresponding to the current speed;

Calculating a second-order Bézier curve as the deceleration curve based on the determined feature points; and

Calculating a deceleration to be applied based on the deceleration curve; and

An output interface is used to output a corresponding train braking instruction based on the calculated deceleration.

The curve method based on the second-order Bézier curve real-time calculation of the present invention to avoid triggering an emergency stop solves the following

technical problem:

1. Determine that the corresponding train deceleration model is generated according to different parameter configurations and used to generate the braking curve.

2. Find the characteristic points of the braking curve calculated in real time based on the second-order Bézier curve in each speed segment of the deceleration model.

3. Based on the second-order Bézier curve, calculate the braking curve in real time to avoid triggering an emergency stop.

Compared with the prior art, the method for real-time calculation of the on-vehicle speed curve to avoid triggering an emergency stop of the present invention can solve the problem that the speed curve of the train is not smooth for efficiency in the prior art, effectively avoiding excessive wear of the brake and saving traction energy.

These and other features and advantages will become apparent by reading the following detailed description and referring to the associated drawings. It should be understood that the foregoing general description and the following detailed description are merely illustrative and do not limit the various aspects claimed.

BRIEF DESCRIPTION OF THE DRAWINGS

In order to be able to understand the manner in which the above features of the present invention are used in detail, the contents briefly summarized above may be described with reference to various embodiments, some of which are shown in the drawings. It should be noted, however, that the drawings show only some typical aspects of the invention and should not be considered as limiting its scope, as the description may allow other equally effective aspects.

FIG. 1 is a flowchart of a method for calculating a train deceleration curve according to an embodiment of the present invention.

FIG. 2 is a schematic diagram of a deceleration model according to an embodiment of the present invention.

FIG. 3 is a flowchart of an example method 300 for processing a deceleration model according to one embodiment of the present invention.

FIG. 4 is a schematic diagram of an example method of obtaining an actual maximum speed limit curve of a line according to an embodiment of the present invention.

FIG. 5 is a schematic diagram of an exemplary method of obtaining feature points required for a second-order Bézier curve according to an embodiment of the present invention.

FIG. 6 is a schematic diagram of applying an example method for obtaining characteristic points required for a second-order Bézier curve to calculate a speed curve according to an embodiment of the present invention.

FIG. 7 is a schematic structural diagram of a train automatic protection device 700 according to an embodiment of the present invention.

detailed description

The present invention is described in detail below with reference to the accompanying drawings. The features of the present invention will be further apparent in the following detailed description.

FIG. 1 is a flowchart of a method 100 for calculating a train deceleration curve according to an embodiment of the present invention.

The method 100 starts at 102 and a deceleration model is established based on the inputs. To realize the speed control function of the vehicle ATP device, external devices need to provide corresponding input information. External input information mainly includes input information related to ground equipment and train related input information. Ground equipment-related input information is the input obtained from a trackside message (such as a wireless message or a transponder message). Such input includes but is not limited to:

(a) Relevant speed limits beside the track;

(b) the slope;

(c) track conditions related to brake suppression;

(d) the orbital conditions associated with the non-electrical sector;

(e) reduce sticking conditions;

(f) specific speed and distance limits; and

(g) National values.

Train-related input information is also input obtained from train data. Such inputs include, but are not limited to:

(a) traction model;

(b) the braking model or braking ratio;

(c) the braking position;

(d) special braking;

(e) Common braking;

(f) Cut the traction interface;

(g) vehicle correction factor;

(h) positive moment of inertia;

(i) train length;

(j) fixed values for speed and distance monitoring; and

(k) Train-related speed limits (such as maximum train speed).

A deceleration model can be established based on the above inputs. For example, a deceleration model as shown in FIG. 2 can be drawn in stages according to each input.

FIG. 2 is a schematic diagram of an exemplary deceleration model according to an embodiment of the present invention. In FIG. 2, the horizontal axis is the real-time train speed V (km / h), and the vertical axis is the calculated train braking deceleration (m / s ² ). As can be seen in Figure 2, the curve in this example deceleration model includes multiple speed-deceleration corresponding segments, and is divided into 5 segments. Optionally, if there are too many segments corresponding to the speed and the deceleration, they need to be pre-processed, and the decelerations are closely combined into one segment. The merged deceleration value is calculated based on the minimum value of each segment before the merge to ensure safety.

The method 300 begins at step 302 with input determination. The inputs here may be ground equipment related input information and train related input information as previously described in connection with FIG. 1.

Next, the method 300 proceeds to step 304 to obtain a speed and deceleration correspondence table. The speed and deceleration correspondence table may be a deceleration model calculated based on the input determined in step 302 as described in FIG. 2.

Subsequently, the method 300 proceeds to step 306 to determine whether there are too many segments included in the deceleration model, such as whether it is greater than a predetermined threshold. According to an embodiment of the present invention, the deceleration model may be set to be divided into a maximum of 7 segments. Therefore, in this step, it can be judged whether the segments included in the deceleration model are larger than 7 segments.

If the contained segments are greater than a predetermined threshold ("Yes", for example, greater than 7 segments), the method 300 proceeds to step 308, and merges adjacent segments that are close in deceleration. The smallest of the segments. Step 308 may further include determining whether the decelerations of the adjacent segments are close based on whether the difference in the decelerations of the adjacent segments is less than a predetermined threshold. This threshold can be set appropriately according to the actual situation. After merging adjacent segments with deceleration close, the method 300 ends.

On the other hand, if the included segment is less than or equal to a predetermined threshold (“No”, for example, 7 segments or less), it means that segment consolidation is not required, and the method 300 ends.

Returning to FIG. 1, as mentioned in the background art, if the vehicle speed control is performed according to the deceleration model calculated in FIG. 2, there is a problem that the curve is not smooth. For example, at the boundary of each speed segment, the applied deceleration will be Sudden change. To overcome this problem, the method of the present invention further smoothes this deceleration model. More specifically, the method 100 proceeds to step 104 to determine a second-order Bézier curve feature point for a segment corresponding to the current vehicle speed. More specifically, in one embodiment, when determining the characteristic points of the second-order Bézier curve, it is necessary to find the real-time calculation based on the second-order Bézier curve for each speed segment of the MRSP of the Most Restrictive Speed Profile of the static line. The characteristic point of the braking curve.

FIG. 4 is a schematic diagram of an actual maximum speed limit curve of a line according to an embodiment of the present invention. As shown in FIG. 4, the horizontal axis represents the position (indicated by the distance d), and the vertical axis represents the speed V. In FIG. 4, there are speed limit curves for different kinds of trains. MRSP is a curve formed by the minimum value of each speed limit at any given position.

FIG. 5 is a schematic diagram of feature points of a second-order Bézier curve according to an embodiment of the present invention. As shown in FIG. 5, let P ₀ , P ₀ ² , and P ₂ be three different points in sequence on a parabola. If the two tangent lines at points P ₀ and P ₂ intersect at point P ₁ , the tangent lines at point P ₀ ² intersect P ₀ P ₁ and P ₂ P ₁ at P ₀ ¹ and P ₁ ¹ , so that the following ratio holds:

Then the curve is a second-order Bézier curve.

When P ₀ and P _{2 are} fixed, the parameter t is introduced so that the above ratio is t: (1-t), that is:

P ₀ ¹ = (1-t) * P ₀ + t * P ₁ ; P ₁ ¹ = (1-t) * P ₁ + t * P ₂ ; P ₀ ² = (1-t) * P ₀ ¹ + t * P ₁ ¹ ;

The points on the second-order Bézier curve can be obtained by the formula P ₀ ² = (1-t) ² * P ₀ + 2t * (1-t) * P ₁ + t ² * P ₂ , where the range of t is 0 ~ 1.

Returning to step 104 in FIG. 1, to calculate the deceleration that needs to be applied, the distance and speed restrictions must be considered, that is, how many distances from the current line position to decelerate from the current speed to how fast, and calculate the smooth deceleration accordingly. curve. Therefore, in step 104, the feature points required for determining the second-order Bézier curve may be obtained for each speed drop point as described below. FIG. 6 is a schematic diagram of applying the above-mentioned exemplary method of obtaining the characteristic points required for the second-order Bézier curve to the calculation of the speed curve according to an embodiment of the present invention. As shown in Figure 6, the required second-order Bézier curve feature points are P ₀ , P ₁ , and P ₂ , where P ₀ is the earliest train that needs to start deceleration derived from the minimum deceleration extracted by the deceleration model in the current segment MRSP. Position, P ₁ is the intersection of the current segment and the next MRSP segment, and P ₂ is the starting point of the next segment MRSP.

Returning to FIG. 1, after obtaining the characteristic points of the second-order Bézier curve in step 104 (that is, P ₀ , P ₁ , P _{2 in} FIG. 6), the method 100 proceeds to step 106 to calculate the second-order Bézier curve in real time based on the second-order Bézier curve. As a deceleration curve. More specifically, after determining the characteristic points of the second-order Bézier curve (for example, P ₀ , P ₁ , and P _{2 in} FIG. 6), according to the formula P ₀ ² = (1-t) ² * P ₀ + 2t * (1- t) * P ₁ + t ² * P ₂ (t ranges from 0 to 1). All points on the curve are calculated. This curve is a smooth and efficient train braking curve, so as to avoid triggering an emergency stop. It can be seen from FIG. 6 that the braking curve provided to the ATP by the present invention is smoother than the braking curve obtained by actually using the reverse acceleration of all positions, and the calculation process is simpler and more efficient. After the train braking curve is calculated, the method 100 ends. Then, the train can calculate the deceleration to be applied based on the deceleration curve, thereby controlling the train to decelerate smoothly.

As an optional embodiment, a deceleration model may be further established for emergency braking and common braking. More specifically, the emergency braking deceleration EBD (Emergency Brake Deceleration) curve and the common braking deceleration SBD (Service Brake Deceleration) curve can be calculated using the rapid braking deceleration and the common braking deceleration respectively according to the algorithm of the present invention, and According to the EBD curve and SBD curve, determine the emergency braking intervention curve EBI (Emergency and Brake Intervention) curve, commonly used braking intervention curve SBI (Service Brake Intervention) curve, allowable speed P (Permitted speed) curve, alarm W (Warning) curve and prompt I (Indication) curve.

FIG. 7 is a schematic structural diagram of a train automatic protection device 700 according to an embodiment of the present invention. As shown in FIG. 7, the train automatic protection device 700 includes at least an input interface 702, a processor 704, and an output interface 706.

The input interface 702 may be used to receive input information from an external device. As described earlier, the input information includes ground equipment related input information and train related input information.

The processor 704 may be configured to perform calculations of a train deceleration curve. For example, as previously described in connection with FIG. 1, performing calculation of a train deceleration curve may include establishing a deceleration model based on the input, where the deceleration model may include multiple speed-deceleration corresponding segments, and for the points corresponding to the current speed Segment, determining a characteristic point of the second-order Bézier curve, and calculating a second-order Bézier curve based on the determined characteristic point as the deceleration curve. The processor 704 may be further configured to calculate a deceleration to be applied based on the deceleration curve.

The output interface 706 can be used to output a train braking instruction based on the calculated deceleration, and is used to implement a smooth deceleration of the train.

What has been described above includes examples of aspects of the claimed subject matter. Of course, it is not possible to describe every conceivable combination of components or methods for the purpose of depicting the claimed subject matter, but one of ordinary skill in the art should recognize that many further combinations of the claimed subject matter and Permutations are possible. Accordingly, the disclosed subject matter is intended to cover all such alterations, modifications, and variations that fall within the spirit and scope of the appended claims.

Claims

A method for calculating a deceleration curve of a train, wherein the method includes:

Establishing a deceleration model based on inputs, the inputs including ground equipment related input information and train related input information, the deceleration model including multiple speed-deceleration corresponding segments;

Determine the characteristic points of the second-order Bézier curve for the segment corresponding to the current speed; and

A second-order Bézier curve is calculated as the deceleration curve based on the determined feature points.
The method according to claim 1, wherein the ground equipment-related input information comprises one or more of the following:

(a) Relevant speed limits beside the track;

(b) the slope;

(c) track conditions related to brake suppression;

(d) the orbital conditions associated with the non-electrical sector;

(e) reduce sticking conditions;

(f) specific speed and distance limits; and

(g) country value, and

The train-related input information includes one or more of the following:

(a) traction model;

(b) the braking model or braking ratio;

(c) the braking position;

(d) special braking;

(e) Common braking;

(f) Cut the traction interface;

(g) vehicle correction factor;

(h) positive moment of inertia;

(i) train length;

(j) fixed values for speed and distance monitoring; and

(k) Train-related speed limits.
The method according to claim 1, wherein the determining the characteristic points of the second-order Bézier curve is determined for each segment of the static line maximum speed curve MRSP.
The method according to claim 3, wherein determining the feature points of the second-order Bézier curve further comprises:

For the second-order Bézier curve, the feature points are P0, P1, and P2, where P0 is the earliest train position to start deceleration derived from the minimum deceleration extracted by the deceleration model in the current segment MRSP, and P1 is the current MRSP segment and The intersection of the next MRSP segment, P2 is the starting point of the next MRSP segment.
The method according to claim 4, wherein calculating the second-order Bézier curve comprises calculating all points on the second-order Bézier curve according to the following formula:

P02 = (1-t) 2 * P0 + 2t * (1-t) * P1 + t2 * P2, where 0 <t <1.
The method of claim 1, wherein the establishing a deceleration model based on the input further comprises:

Confirm input

Get the speed and deceleration correspondence table;

Determining whether the number of segments included in the deceleration model is greater than a predetermined threshold; and

If it is determined that the number of segments is greater than a predetermined threshold, adjacent segments with a deceleration approaching are merged.
The method according to claim 6, wherein merging adjacent segments with a deceleration close to each other further comprises: taking a minimum value of each segment before merging as a deceleration value of the merging segment.
The method of claim 1, wherein the establishing a deceleration model based on the input further comprises separately establishing a deceleration model for emergency braking and commonly used braking.
An automatic train protection device is characterized in that it includes:

An input interface for receiving input from an external device, the input including ground device related input information and train related input information;

A processor configured to:

Establishing a deceleration model according to the input, the deceleration model including a plurality of speed-deceleration corresponding segments;

Determine the characteristic points of the second-order Bézier curve for the segment corresponding to the current speed; and

Calculating a second-order Bézier curve as the deceleration curve based on the determined feature points; and

An output interface is used to output a corresponding train braking instruction based on the deceleration curve.
The automatic train protection device according to claim 9, wherein the processor is further configured to:

A deceleration to be applied is calculated based on the deceleration curve.