Train slip exiting working condition judgment method based on speed measurement sensor

Abstract

The invention discloses a method for judging the slipping exiting working condition of a train based on speed measurement sensors. The method comprises the following steps that 1, the two same speed measurement sensors are arranged on the train; 2, after the train enters a slipping stage, the two speed measurement sensors periodically measure respective accelerated speeds respectively, the weight coefficient of the accelerated speeds of the two sensors in the previous period is calculated according to the accelerated speed measurement result in the previous period, and the fusion filtering accelerated speed in the current period is calculated according to the accelerated speed and the weight coefficient; and step 3, judging whether the train exits the slip working condition or not according to the weight coefficient and the fusion filtering acceleration. According to the method, the correctness of the vehicle-mounted signal system for judging that the train exits from the slip working condition is improved, and the safety of train speed calculation and position calculation is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of urban rail transit, and in particular to a method for determining a train exiting a skidding condition based on a speed measuring sensor. Background Art

[0002] In the field of urban rail transit, the on-board signal system generally relies on the speed sensor installed on the end of the train axle to measure the speed of the train in order to complete the safe positioning function of the train. However, since the speed measurement accuracy of the speed sensor depends on the working state of the axle, once the train slips, the rotation of the axle cannot correctly reflect the displacement of the train, which will affect the safe positioning function of the train. In order to deal with the slipping scenario, the safe execution of the positioning function can generally be ensured by safely overestimating the speed and displacement of the train through a calculation model during the slipping stage. After the speed and acceleration measured by the speed sensor return to a reasonable threshold, it is determined to have exited the slipping, and then the speed sensor's measurement data is restored. However, due to the intervention of the vehicle's anti-skid system, the speed and acceleration values ​​measured by the speed sensor during the slipping stage may meet the conditions for exiting the slipping, and the on-board signal system exits the slipping in advance. However, because the train is still in a slipping condition, the speed measured by the speed sensor will be lower than the actual displacement speed of the train, causing errors in the train positioning calculation, such as Figure 2 As shown in the figure, the underestimation of speed and displacement causes the system to fail to correctly judge that the train has run a red light, affecting driving safety. Summary of the invention

[0003] The purpose of the present invention is to overcome the shortcomings of the prior art that after the train skids, the intervention of the vehicle anti-skid system leads to errors in the actual positioning calculation of the train, affecting driving safety, and provide a method for determining the train exiting skidding condition based on a speed sensor.

[0004] The purpose of the present invention is achieved through the following technical solutions: The method for determining a train exiting a skidding condition based on a speed sensor comprises the following steps: Step 1: two identical speed sensors are installed on the train; Step 2: After the train enters the skidding stage, the two speed sensors periodically measure their respective accelerations, calculate the weight coefficients of the accelerations of the two sensors in the previous cycle based on the acceleration measurement results of the previous cycle, and calculate the fused filtered acceleration of the current cycle based on the accelerations and the weight coefficients; Step 3: Determine whether the train has exited the slipping condition based on the weight coefficient and the fused filter acceleration.

[0005] This solution takes into account that when the actual train skids, the acceleration measurement of the speed sensor will change significantly, and the weight coefficient of the acceleration will also change accordingly and become unstable; after the train exits the skid, the weight coefficient will return to the expected stable value, and the fused filter acceleration calculated by the acceleration and weight coefficient will also return to stability. Therefore, the design of this solution improves the accuracy of the on-board signal system in determining the train exiting the skid condition, and improves the safety of the train speed calculation and position calculation.

[0006] Preferably, in step 1, the two speed sensors are arranged on different axles of the train. If they are arranged on the same axle, they may fail at the same time due to common factors, and being arranged on different axles ensures the accuracy of the speed measurement of the speed sensors.

[0007] Preferably, in step 2, the weight coefficients of the accelerations of the two sensors in the previous cycle are calculated using the acceleration measurement results of the previous cycle, specifically: The two speed sensors are set to be speed sensor a and speed sensor b. The weight coefficient of speed sensor a in the previous cycle is Ka_n-1, and the weight coefficient of speed sensor b is K b_n-1. Ka_n-1=Ab_n-1 / (Aa_n-1+Ab_n-1), Kb_n-1=1-Ka_n-1; Wherein, Aa_n-1 is the actual measured acceleration of the speed sensor a in the previous cycle, and Ab_n-1 is the actual measured acceleration of the speed sensor b in the previous cycle.

[0008] Preferably, the formula for calculating the fusion filter acceleration of the current cycle according to the acceleration and the weight coefficient is: A_filter_n=Ka_n-1*Aa_n+Kb_n-1*Ab_n, Wherein, Aa_n is the actual measured acceleration of speed sensor a in the current cycle, and Ab_n is the actual measured acceleration of speed sensor b in the current cycle.

[0009] In the calculation of train speed and displacement, speed-time is a linear relationship. Therefore, in the non-slip stage, the change in angular velocity measured by the two speed sensors is predictable. The speed measured by the speed sensor in this cycle is linearly related to the speed measured in the previous cycle. This linear relationship can be measured by filtered acceleration. Moreover, because the working principle, installation method, and speed measurement progress of the two identical speed sensors are the same, when there is no slip, the weights of the speed measurement results of the two speed sensors are expected to be the same, that is, 0.5 each.

[0010] Preferably, the step 3 is specifically as follows: judging whether the train meets the conditions for exiting the slipping condition by the weight coefficient and the fused filter acceleration; if the conditions for exiting the slipping condition are met, judging that the train has exited the slipping condition; if the conditions for exiting the slipping condition are not met, judging that the train has not exited the slipping condition, and the conditions for exiting the slipping condition are specifically as follows: Within a set time, the weight coefficients of the weight coefficients Ka_n-1 and K b_n-1 approach 0.5 and within a set time, the fusion filter acceleration is within a set threshold.

[0011] Preferably, the weight coefficients of the weight coefficient Ka_n-1 and the weight coefficient K b_n-1 are close to 0.5. Considering the improvement of the success rate of exiting skidding in practical application, the weight coefficients of the weight coefficient Ka_n-1 and the weight coefficient K b_n-1 are specifically within an interval with 0.5 as the mean within a set time, such as 0.47-0.53.

[0012] Preferably, the condition for exiting the slipping condition further includes: within a set time, the fused filter acceleration is a negative value. The fused filter acceleration being a negative value indicates that the train has returned to the braking stage, so the train exits the slipping condition.

[0013] Preferably, if the train fails to meet the conditions for exiting the slipping condition within the set time, resulting in inaccurate positioning information, the train's onboard signal system loses positioning and controls the train to the safe side. Losing positioning means that the onboard signal system should no longer rely on positioning information to track the operation of the train. Guiding to the safe side is a safer and less risky operation mode that the onboard signal system will choose, such as continuously applying normal braking or emergency braking to ensure the safety of the train and passengers.

[0014] The beneficial effects of the present invention are as follows: the present invention evaluates the motion trend of the train axle through a dual speed sensor fusion algorithm, and combines the speed and acceleration values ​​measured by the speed sensor to ensure that the on-board signal system can correctly determine that the train exits the slipping condition. The present invention improves the accuracy of the on-board signal system in determining that the train exits the slipping condition, and improves the safety of the train speed calculation and position calculation. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 is a flow chart of the present invention; Figure 2 It is a schematic diagram of the difference between the train position calculated by the system and the actual skidding train position in the prior art; Figure 3 It is a schematic diagram of acceleration and weight coefficient fluctuation of the present invention. DETAILED DESCRIPTION

[0016] Example embodiments will now be described more fully with reference to the accompanying drawings. However, example embodiments can be implemented in a variety of forms and should not be construed as limited to the examples set forth herein; rather, these embodiments are provided so that this application will be more comprehensive and complete and fully convey the concept of the example embodiments to those skilled in the art.

[0017] In addition, described feature, structure or characteristic can be combined in one or more embodiments in any suitable manner. In the following description, many specific details are provided to provide a full understanding of the embodiments of the present application. However, those skilled in the art will appreciate that the technical scheme of the present application can be put into practice without one or more of the specific details, or other methods, components, devices, steps, etc. can be adopted. In other cases, known methods, devices, realizations or operations are not shown or described in detail to avoid blurring the various aspects of the application.

[0018] The flowcharts shown in the accompanying drawings are only exemplary and do not necessarily include all the contents and operations / steps, nor must they be executed in the order described. For example, some operations / steps can be decomposed, and some operations / steps can be combined or partially combined, so the actual execution order may change according to actual conditions.

[0019] Example: The train exit skidding condition determination method based on speed sensor, such as Figure 1 As shown, the following steps are included: Step 1: two identical speed sensors are installed on the train; Step 2: After the train enters the skidding stage, the two speed sensors periodically measure their respective accelerations, calculate the weight coefficients of the accelerations of the two sensors in the previous cycle based on the acceleration measurement results of the previous cycle, and calculate the fused filtered acceleration of the current cycle based on the accelerations and the weight coefficients; Step 3: Determine whether the train has exited the slipping condition based on the weight coefficient and the fused filter acceleration.

[0020] This solution takes into account that when the actual train skids, the acceleration measurement of the speed sensor will change significantly, and the weight coefficient of the acceleration will also change accordingly and become unstable; after the train exits the skid, the weight coefficient will return to the expected stable value, and the fused filter acceleration calculated by the acceleration and weight coefficient will also return to stability. Therefore, the design of this solution improves the accuracy of the on-board signal system in determining the train exiting the skid condition, and improves the safety of the train speed calculation and position calculation.

[0021] In step 1, the two speed sensors are arranged on different axles of the train. If they are arranged on the same axle, they may fail at the same time due to common factors. Arranging them on different axles ensures the accuracy of the speed measurement of the speed sensors.

[0022] In step 2, the weight coefficients of the accelerations of the two sensors in the previous cycle are calculated using the acceleration measurement results of the previous cycle, specifically: The two speed sensors are set to be speed sensor a and speed sensor b. The weight coefficient of speed sensor a in the previous cycle is Ka_n-1, and the weight coefficient of speed sensor b is K b_n-1. Ka_n-1=Ab_n-1 / (Aa_n-1+Ab_n-1), Kb_n-1=1-Ka_n-1; Wherein, Aa_n-1 is the actual measured acceleration of the speed sensor a in the previous cycle, and Ab_n-1 is the actual measured acceleration of the speed sensor b in the previous cycle.

[0023] The formula for calculating the fusion filter acceleration of the current cycle based on the acceleration and the weight coefficient is: A_filter_n=Ka_n-1*Aa_n+Kb_n-1*Ab_n, Wherein, Aa_n is the actual measured acceleration of speed sensor a in the current cycle, and Ab_n is the actual measured acceleration of speed sensor b in the current cycle.

[0024] In the calculation of train speed and displacement, speed-time is a linear relationship. Therefore, in the non-slip stage, the change in angular velocity measured by the two speed sensors is predictable. The speed measured by the speed sensor in this cycle is linearly related to the speed measured in the previous cycle. This linear relationship can be measured by filtered acceleration. Moreover, because the working principle, installation method, and speed measurement progress of the two identical speed sensors are the same, when there is no slip, the weights of the speed measurement results of the two speed sensors are expected to be the same, that is, 0.5 each.

[0025] The step 3 is specifically as follows: judging whether the train meets the conditions for exiting the slipping condition by using the weight coefficient and the fused filter acceleration; if the conditions for exiting the slipping condition are met, judging that the train has exited the slipping condition; if the conditions for exiting the slipping condition are not met, judging that the train has not exited the slipping condition. The conditions for exiting the slipping condition are specifically as follows: Within a set time, the weight coefficients of the weight coefficients Ka_n-1 and K b_n-1 approach 0.5 and within a set time, the fusion filter acceleration is within a set threshold.

[0026] The weight coefficients of the weight coefficient Ka_n-1 and the weight coefficient K b_n-1 are close to 0.5. Considering the improvement of the success rate of exiting skidding in practical application, the weight coefficients of the weight coefficient Ka_n-1 and the weight coefficient K b_n-1 are specifically within an interval with 0.5 as the mean within the set time, such as 0.47-0.53.

[0027] The condition for exiting the slipping condition also includes: within a set time, the fused filter acceleration is a negative value. The fused filter acceleration is a negative value, indicating that the train has returned to the braking stage, so the train exits the slipping condition.

[0028] If the train fails to meet the conditions for exiting the slipping condition within the set time, resulting in inaccurate positioning information, the train's onboard signal system loses positioning and controls the train to the safe side. Loss of guidance positioning means that the onboard signal system should no longer rely on positioning information to track the operation of the train. Guiding to the safe side is a safer and less risky operation mode that the onboard signal system will choose, such as continuously applying normal braking or emergency braking to ensure the safety of the train and passengers.

[0029] In this embodiment, a fluctuation of acceleration and weight coefficient is as follows Figure 3 As shown in the figure, the filtered acceleration and the weight coefficient K (including the weight coefficient Ka_n-1 and the weight coefficient K b_n-1) fluctuate during the slipping stage. It is judged that the train is in the slipping stage. After 161 cycles, the slipping is exited, and the speed curve, acceleration curve and filtered acceleration return to normal, and the weight coefficient stabilizes and tends to 0.5.

[0030] Those skilled in the art will readily appreciate other embodiments of the present application after considering the specification and practicing the embodiments disclosed herein. The present application is intended to cover any variations, uses or adaptations of the present application, which follow the general principles of the present application and include common knowledge or customary technical means in the art that are not disclosed in the present application.

[0031] It should be understood that the present application is not limited to the precise structures that have been described above and shown in the drawings, and that various modifications and changes may be made without departing from the scope thereof. The scope of the present application is limited only by the appended claims.

Claims

1. A method for determining the train exiting skidding condition based on a speed sensor. Its characteristics are: The following steps are involved: Step 1: two identical speed sensors are installed on the train; Step 2: After the train enters the skidding stage, the two speed sensors periodically measure their respective accelerations, calculate the weight coefficients of the accelerations of the two sensors in the previous cycle based on the acceleration measurement results of the previous cycle, and calculate the fused filtered acceleration of the current cycle based on the accelerations and the weight coefficients; Step 3: Determine whether the train has exited the slipping condition based on the weight coefficient and the fused filter acceleration.

2. The method for determining a train exiting a skidding condition based on a speed sensor according to claim 1, Its characteristics are: In the step 1, two speed sensors are arranged on different axles of the train.

3. The train exit skidding condition determination method based on a speed sensor according to claim 1, Its characteristics are: In step 2, the weight coefficients of the accelerations of the two sensors in the previous cycle are calculated using the acceleration measurement results of the previous cycle, specifically: The two speed sensors are set to be speed sensor a and speed sensor b. The weight coefficient of speed sensor a in the previous cycle is Ka_n-1, and the weight coefficient of speed sensor b is K b_n-1. Ka_n-1=Ab_n-1 / (Aa_n-1+Ab_n-1), Kb_n-1=1-Ka_n-1; Wherein, Aa_n-1 is the actual measured acceleration of the speed sensor a in the previous cycle, and Ab_n-1 is the actual measured acceleration of the speed sensor b in the previous cycle.

4. The method for determining a train exiting a skidding condition based on a speed sensor according to claim 3, Its characteristics are: The formula for calculating the fusion filter acceleration of the current cycle based on the acceleration and the weight coefficient is: A_filter_n=Ka_n-1*Aa_n+Kb_n-1*Ab_n, Wherein, Aa_n is the actual measured acceleration of speed sensor a in the current cycle, and Ab_n is the actual measured acceleration of speed sensor b in the current cycle.

5. The method for determining a train exiting skidding condition based on a speed sensor according to claim 4, Its characteristics are: The step 3 is specifically as follows: judging whether the train meets the conditions for exiting the slipping condition by using the weight coefficient and the fused filter acceleration; if the conditions for exiting the slipping condition are met, judging that the train has exited the slipping condition; if the conditions for exiting the slipping condition are not met, judging that the train has not exited the slipping condition. The conditions for exiting the slipping condition are specifically as follows: Within a set time, the weight coefficients of the weight coefficients Ka_n-1 and K b_n-1 approach 0.5 and within a set time, the fusion filter acceleration is within a set threshold.

6. The method for determining a train exiting a skidding condition based on a speed sensor according to claim 5, Its characteristics are: The weight coefficient of the weight coefficient Ka_n-1 and the weight coefficient K b_n-1 is close to 0.

5. Specifically, the weight coefficient of the weight coefficient Ka_n-1 and the weight coefficient K b_n-1 fluctuates within a range within a set time.

7. The method for determining a train exiting a skidding condition based on a speed sensor according to claim 5, Its characteristics are: The condition for exiting the slipping condition also includes: within a set time, the fused filter acceleration is a negative value.

8. The method for determining a train exiting skidding condition based on a speed sensor according to claim 5, 6 or 7, Its characteristics are: If the train does not meet the conditions for exiting the slipping condition within the set time, the train's onboard signal system will lose its position and control the train to the safe side.

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