Patent Publication Number: US-2020283039-A1

Title: Detecting and optimizing the stopping-point accuracy of a vehicle

Description:
The present invention relates to a system for detecting and optimizing the stopping point accuracy of a vehicle. 
     The operation of rail-bound traffic systems is becoming increasingly automated, which by way of example is apparent in the use of driverless systems in metros or subways. During the course of this automation, in particular in the field of local transport systems, it is also necessary to protect the passengers on the platform. For this purpose, inter alia platform doors are used that are integrated into walls that are often embodied from glass and separate the platform of a stopping point from the region of the rails. In this manner, people are prevented from falling into the path of the vehicle or onto the track. The use of such protective measures however means that when a vehicle is stopped, the vehicle doors of said vehicle must be brought into as precise an alignment as possible with the platform doors, since a rapid and safe exchange of passengers may only take place in this manner. 
     The stopping point accuracy that is sought after for this purpose currently allows deviations of approximately 10 cm to approximately 30 cm. If the vehicle doors are not brought sufficiently into alignment with the platform doors, the passage for the exchange of passengers is thus narrowed and as a consequence this may lead to a crush among the passengers culminating in a panic reaction in the same passengers. As a result of this, injuries or even possibly deaths may occur. 
     The object is therefore to provide an improved procedure for detecting the stopping point accuracy, which is achieved during operation of a rail-bound vehicle, or for detecting deviations that occur with regard to the stopping point accuracy and as a consequence to render it possible to optimize the stopping point accuracy by way of an automated correction of the braking curve of a vehicle. As a consequence, it is to be possible using signal technology to realize a stopping point accuracy of 10 cm or less. 
     In accordance with the invention, an apparatus for detecting and optimizing the stopping point accuracy of a vehicle, comprising at least one sensor unit that may be arranged on the vehicle and at least one evaluating unit that is connected to the at least one sensor unit. The at least one sensor unit is embodied so as to measure a gap relative to a gap profile that is arranged on a stopping point that the vehicle travels to and also so as to transmit the measurement result to the at least one evaluating unit that is connected to the sensor unit. 
     In accordance with the invention, a system is provided for detecting and optimizing the stopping point accuracy of a vehicle, said sensor arrangement comprising at least one sensor unit that is arranged on the vehicle, at least one gap profile that is arranged on a stopping point that the vehicle travels to and at least one evaluating unit that is connected to the at least one sensor unit. In accordance with the invention, the at least one sensor unit is embodied so as to measure the gap with respect to the at least one gap profile and so as to transmit the measurement result to the at least one evaluating unit that is connected to the sensor unit. 
     The solution in accordance with the invention has the advantage that by way of an evaluation of analogue measurement values, which result from a measurement of the gap from a sensor unit to a corresponding gap profile that is mounted on the track side, it is possible using signal technology to reliably detect the absolute stopping point accuracy that is achieved during operation. 
     As a consequence, it is moreover rendered possible to optimize the stopping point accuracy by way of the automated correction of the braking curve for the vehicle. 
     Dynamic tests during commissioning are furthermore reduced by means of such an automated procedure of identifying the stopping point, which is rendered possible by the system in accordance with the invention. Moreover, the invention offers advantages in the location synchronization or in the distance detection for a vehicle since for example a wheel diameter of the vehicle that reduces over the time may be identified owing to a changed stopping point accuracy and may be automatically compensated by adapting the braking curve for the vehicle. 
     In accordance with one advantageous embodiment of the system in accordance with the invention, it is provided that the at least one sensor unit that is arranged on the vehicle comprises two sensors for the gap measurement. Sensors of this type that are provided for a gap measurement are capable of detecting objects embodied from different materials such as metal, wood or synthetic material. Moreover, environmental influences such as moisture, dust and smoke do not impair the measuring accuracy of said sensors. Furthermore, precipitation such as rain or snow in normal density also does not lead to impairment of the functions of the sensors with the result that it is also possible to use said sensors at stopping points above ground. Furthermore, it is optionally possible by way of constructive measures to provide an installation that is protected against environmental influences. 
     Advantageously, furthermore an arrangement of the at least one sensor unit is provided below a door of the vehicle. As a consequence, it is rendered possible, in particular in the case of stopping points that have a ground level entrance and exit, to arrange the sensor unit that is arranged below the door at the same height as the corresponding gap profile that is fastened to the platform of the stopping point. 
     In accordance with the invention, alternatively or in addition thereto an arrangement of the at least one sensor unit may be provided on the underside of the vehicle and an arrangement of the at least one gap profile may be provided in the track  19 . As a consequence, a redundancy and an increased safety that results from this redundancy are achieved during the procedure of detecting the stopping point accuracy of a vehicle. Advantageously, it is moreover possible to provide a validation of the measurement results, which are detected by multiple sensor units, by means of a plausibility check. As a consequence, it is possible to identify defective sensor units. 
     It is particularly preferred that at least two sensors for the gap measurement and also an evaluating unit that is connected to said sensors are provided on the vehicle. As a consequence, it is not only detected whether the vehicle has come to a standstill at the stopping point or has missed the stopping point but rather it is rendered possible to determine to what extent deviations occur with respect to the optimal stopping point. 
     Advantageously, each side of the vehicle moreover is provided with at least two evaluating units and also sensor units that are connected to said evaluating units. As a consequence, in accordance with the invention a reliable realization is rendered possible using signal technology, said realization ensuring a function of the system even in the case of a defect of one of the evaluating units or one of the sensor units. 
     In accordance with a preferred embodiment of the system in accordance with the invention, an evaluating unit and also a sensor unit that is connected to said evaluating unit are provided both on the first door as well as on the last door on each side of the vehicle. It is therefore possible to perform a plausibility check as to whether the entire vehicle, in other words over its entire length, is standing at the platform of a stopping point. Furthermore, it is possible to perform a plausibility check as to which side the platform is located on and whether consequently the doors may be released for opening. 
     In one further preferred variant of the invention, the at least one evaluating unit is integrated into a train safety computer of the vehicle. This has the advantage that the train safety computer, by way of example an automatic train protection (ATP) device, has a communications interface to a facility for controlling the train, by way of example an automatic train operation (ATO) device, and there is thus the possibility of handing over the required correcting values for the braking curve in relation to the stopping point accuracy directly from the train safety computer to the train control system. 
     The at least one evaluating unit of the system in accordance with the invention advantageously has means for the automated correction of the braking curve of the vehicle. In this case, the means may be provided as a microprocessor, by way of example within the scope of an integrated circuit. As a consequence, it is rendered possible that not only a stopping point accuracy is detected but rather also that an optimizing procedure is performed in relation to the detection of the stopping point accuracy in that the braking curve for the vehicle is modified taking into account the stopping point accuracy that is determined. 
     Advantageously, the at least one evaluating unit moreover has means for transmitting the values with regard to the automated correction of the braking curve of the vehicle to a control facility of the vehicle. In this case, the means may be embodied as a wireless or wire-connected communications interface. This is in particular advantageous for the case that the evaluating unit is not integrated into the train safety computer since in this manner it is nevertheless possible to perform an automated optimizing procedure of the braking curve of the vehicle. 
     In accordance with a further preferred embodiment of the invention, the at least one gap profile has the shape of a rectangle, a triangle or a trapezoid. In the case of a gap profile having the shape of a rectangle, it is therefore rendered possible to detect whether the vehicle has come to a standstill at the stopping point taking into account the permissible deviations or whether said vehicle has missed the stopping point. In the case of a gap profile having the shape of a triangle it is further rendered possible that the deviations with respect to the optimal stopping point may also be detected. A gap profile having the shape of a trapezoid moreover renders it possible that in the case of a sufficiently precise stopping point of the vehicle, it is not necessary to perform any permanent corrections of the vehicle position. 
     It is preferred that the at least one gap profile is embodied from an in particular curved sheet metal, a synthetic material body or a concrete molded part. Gap profiles that are embodied from materials of this type are simple to produce and are nevertheless suitable for a gap measurement by means of the sensor unit, in particular by means of a sensor unit that comprises two ultrasonic sensors. 
     In a further preferred embodiment, the at least one gap profile is embodied in a stepped manner on its surfaces that extend obliquely. This embodiment offers the advantages in the case of the gap measurement being performed by the at least one sensor unit, since sometimes sensors that may detect smooth oblique surfaces poorly are used for the gap measurement. 
     Moreover, a vehicle having an apparatus in accordance with the invention is proposed. 
    
    
     
       The above-described characteristics, features and advantages of this invention and also the manner in which these are achieved become more clearly and obviously understandable in conjunction with the following description of the exemplary embodiments that are further explained in conjunction with the drawings. In the drawings: 
         FIG. 1  shows an apparatus that is known from the prior art for detecting the stopping point accuracy of a vehicle, 
         FIG. 2  shows a vehicle according to the system in accordance with the invention illustrated in a side view, 
         FIG. 3  shows a vehicle according to the system in accordance with the invention in an underside view, 
         FIG. 4  shows a stopping point according to the system in accordance with the invention, 
         FIG. 5  shows a first exemplary embodiment for a gap measurement by means of a first and a second sensor and a gap profile in a rectangular shape, 
         FIG. 6  shows a second exemplary embodiment for a gap measurement by means of a first and a second sensor and a gap profile in a rectangular shape, 
         FIG. 7  shows a third exemplary embodiment for a gap measurement by means of a first and a second sensor and a gap profile in a rectangular shape, 
         FIG. 8  shows a first exemplary embodiment for a gap measurement by means of a first and a second sensor and a gap profile in a triangular shape, 
         FIG. 9  shows a second exemplary embodiment for a gap measurement by means of a first and a second sensor and a gap profile in a triangular shape, 
         FIG. 10  shows a third exemplary embodiment for a gap measurement by means of a first and a second sensor and a gap profile in a triangular shape, 
         FIG. 11  shows a first exemplary embodiment for a gap measurement by means of a first and a second sensor and a gap profile in a trapezoid shape, 
         FIG. 12  shows a second exemplary embodiment for a gap measurement by means of a first and a second sensor and a gap profile in a trapezoid shape, 
         FIG. 13  shows a third exemplary embodiment for a gap measurement by means of a first and a second sensor and a gap profile in a trapezoid shape, 
         FIG. 14  shows a fourth exemplary embodiment for a gap measurement by means of a first and a second sensor and a gap profile in a trapezoid shape, 
         FIG. 15  shows a fifth exemplary embodiment for a gap measurement by means of a first and a second sensor and a gap profile in a trapezoid shape, 
         FIG. 16  shows a first exemplary embodiment of a gap profile in a trapezoid shape, 
         FIG. 17  shows a second exemplary embodiment of a gap profile in a trapezoid shape. 
     
    
    
     The apparatus in accordance with the invention for detecting the stopping point accuracy of a vehicle  1  is explained below. The vehicle  1  in accordance with the invention is in this case, as illustrated in the figures in an exemplary manner, preferably but not limiting a rail-bound vehicle  1 , which moves on a track  19  that comprises rails  20 . 
       FIG. 1  illustrates an apparatus that is known from the prior art for detecting the stopping point accuracy of a vehicle  1  in which two odometer pulse generators  3 , two radar devices  4  and also two balise antennae  5  are provided. The vehicle  1  is preferably a rail-bound vehicle  1 , which moves on rails  20  that are a component of a track  19 . In this case, a location synchronization is realized using the point-shaped balise transmitting channel, which is formed between the balise antennae  5  of the vehicle  1  and the track-side fixed data Balise  6  that is preferably arranged in the track  19 . Moreover, the distance traveled is calculated via the known wheel circumference by means of the odometer pulse generators  3 . The vehicle  1  is brought to a standstill at the stopping point via an engagement of the brakes. The possible deviations of the balise center identification for the location synchronization, an erroneous distance-traveled value as a result of the wheels possibly sliding during a braking procedure and inaccuracies in the wheel circumference play an important role for the calculation of the stopping point accuracy. From a safety technical point of view, it is hitherto therefore permissible to only realize stopping point accuracies up to approximately 1 m. Moreover, the absolute stopping point accuracies that are achieved during operation or the deviations that occur during this operation are not detected. Furthermore, it is also not possible to optimize the stopping point by way of automated correction of the braking curve of the vehicle. Sensor weaknesses of the radar sensors are only to be taken into account when using additional radar sensors for calculating the distance traveled which is why in this case it is also not possible to obtain a satisfactory result with regard to the stopping point accuracy. 
       FIG. 2  illustrates a rail-bound vehicle  1  that is illustrated in a side view and a track  19  that comprises a rail  20  is traveled on using said vehicle, according to the system in accordance with the invention, said rail-bound vehicle respectively comprising a sensor unit  7  that is arranged below the two outer doors  2 , said sensor unit being respectively connected to an evaluating unit  11 . The sensor units  7  that are attached to the vehicle  1  for detecting the absolute stopping accuracy are required for the gap measurement and may comprise by way of example ultrasonic sensors. In the present case, two Balises  5 , two odometer pulse generators  3  and two radar devices  4  may be provided for a rough locating procedure of the vehicle  1  and the actual functions of train safety remain the same. 
       FIG. 3  illustrates the rail-bound vehicle  1  in an underside view which is why it is apparent that the sensor units  7  are arranged respectively on the two sides of the vehicle  1  in the region of the two outer doors. 
     Moreover,  FIG. 4  illustrates a stopping point that is fitted out in a manner according to the present invention and comprises a platform that has gap profiles  10  on the platform side below the platform doors and at the same height of the sensor units  7  of the vehicle  1 . The gap profiles in this case are arranged in such a manner that they may be detected by the sensor units  7  that are arranged on the two outer doors  2  of the vehicle  1 . Moreover, in  FIG. 4  eight doors  8  are visible at the stopping point, said doors being integrated at the stopping point into a surrounding wall  9  that is preferably embodied from glass and it is rendered possible for passengers to enter the vehicle  1  through said doors. Two of the sensor units  7 , which are allocated to a door  2 , respectively provide two independent analogue values, by way of example a voltage value and/or current value, to an evaluating unit  11  so as to evaluate and to determine the gap a 1 , a 2  between a sensor unit and a gap profile  10 . The height of the output value in this case is proportional to the gap a 1 , a 2 . In the present case, two evaluating units  11  are required on each side of the vehicle  1  for a reliable realization using signal technology. 
     The gap profile  10  and the two sensors  12 ,  13  are described below, which render it possible to detect the absolute stopping point accuracy that is achieved during operation and to optimize the stopping point. 
       FIG. 5  illustrates a first exemplary embodiment for a gap measurement by means of a first and a second sensor  12 ,  13  and a gap profile  10  in a rectangular shape. The shape of a rectangle for the gap profile  10  renders it possible only to detect whether the vehicle  1  has come to a standstill at the stopping point or whether said vehicle has missed the stopping point. In  FIG. 5 , it is apparent that the two sensors  12 ,  13  detect the protruding region of the gap profile  10 . The result of this is that the vehicle  1  has come to a standstill at the stopping point in such a manner that the gap profile  10  that is arranged in the region of a door  8  at the stopping point is opposite the two sensors  12 ,  13  that are arranged in the region of the door  2  of the vehicle  1 , which results in two gaps a 1 , a 2  of equal size between the protruding region of the gap profile  10  and the sensors  12 ,  13 . The stopping point was accordingly reached in an optimal manner. 
       FIG. 6  illustrates a second exemplary embodiment for a gap measurement by means of a first and a second sensor  12 ,  13  and a gap profile  10  in a rectangular shape in which the vehicle  1  has reached the stopping point too early, in other words has come to a standstill too early. In comparison to the second sensor  13 , the first sensor  12  has a greater gap a 1  with respect to the gap profile  10 . Only the gap a 2  from the second sensor  13  with respect to the gap profile  10  has the desired value. 
       FIG. 7  illustrates a third exemplary embodiment for a gap measurement by means of a first and a second sensor  12 ,  13  and a gap profile  10  in a rectangular shape in which the vehicle  1  has reached the stopping point too late, in other words has come to a standstill too late. Here, in comparison to the first sensor  12 , the second sensor  13  has a greater gap a 2  with respect to the gap profile  10 . The gap a 1  from the first sensor  12  with respect to the gap profile  10  conversely has the desired value. 
       FIG. 8  illustrates a first exemplary embodiment for a gap measurement by means of a first and a second sensor  12 ,  13  and a gap profile  10  in a triangular shape. It is also rendered possible by way of the triangular shape to detect deviations with respect to the optimal stopping point. In the case of the exemplary embodiment that is illustrated in  FIG. 8 , the stopping point has been reached by the vehicle  1  in an optimal manner, in other words the vehicle  1  has come to a standstill neither too early nor too late. A case of this type in which the gap between the first sensor and the gap profile  10  and also the second sensor and the gap profile  10  coincides exactly with a 1 =a 2 , will not occur in reality since small differences between a 1  and a 2  cannot be ruled out. 
       FIG. 9  illustrates a second exemplary embodiment for a gap measurement by means of a first and a second sensor  12 ,  13  and a gap profile  10  in a triangular shape in which the stopping point has been reached too early, in other words the vehicle has come to a standstill too early. The gap a 1  of the first sensor  12  with respect to the gap profile  10  is greater than the gap a 2  of the second sensor  13  with respect to the gap profile  10 . In the present case, the braking curve of the vehicle  1  should be corrected in that the braking curve is modified to the effect that the vehicle  1  brakes later and/or less intensely and as a consequence travels further with the result that a position is reached in which the two gaps a 1  and a 2  of the sensors  12 ,  13  from the gap profile  10  approximately coincide. 
       FIG. 10  illustrates a third exemplary embodiment for a gap measurement by means of a first and a second sensor  12 ,  13  and a gap profile  10  in a triangular shape in which the stopping point has been reached too late, in other words the vehicle has come to a standstill too late. The gap a 2  of the second sensor  13  with respect to the gap profile  10  is greater than the gap a 1  of the first sensor  12  with respect to the gap profile  10 . In the present case, the braking curve of the vehicle  1  should be corrected in that the braking curve is modified to the extent that the vehicle  1  brakes earlier and/or more intensely and as a consequence does not travel as far with the result that a position is reached in which the two gaps a 1  and a 2  of the sensors  12 ,  13  from the gap profile  10  approximately coincide. 
       FIG. 11  illustrates a first exemplary embodiment for a gap measurement by means of a first and a second sensor  12 ,  13  and a gap profile  10  in a trapezoid shape. A gap profile in a trapezoid shape is used in order to prevent non-permanent corrections of the braking curve of the vehicle  1  being required in the case of a sufficiently precise stopping point, since the gaps a 1 , a 2  that are measured by the two sensors  12 ,  13  do not coincide. In this case, the different sections of the trapezoid are allocated value ranges  14 ,  15 ,  16 ,  17 ,  18 , which make a statement regarding the accuracy of the stopping point. In  FIG. 11 , the two sensors  12 ,  13  determine a measuring value in the value range  14 , which results in the stopping point being adhered to particularly precisely and that a correction of the vehicle braking curve is not required. The doors  2  of the vehicle  1  and the platform doors  8  may be opened in the case of a vehicle being at a standstill. Provided therefore that the two sensors  12 ,  13  are in the value range  14 , the stopping point has been reached particularly precisely by the vehicle  1 , with the result that the doors  2  of the vehicle  1  may be opened and a correction or calibration of the braking curve of the vehicle  1  is not required. 
       FIG. 12  illustrates a second exemplary embodiment for a gap measurement by means of a first and a second sensor  12 ,  13  and a gap profile  10  in a trapezoid shape. In this case, the first sensor  12  is in the value range  15  and the second sensor is in the value range  14 . This means that the stopping point is still sufficiently precise with the result that the doors  2  of the vehicle  1  may open when the vehicle  1  is at a standstill. However, a correction or calibration of the braking curve of the vehicle  1  should be performed so that the vehicle  1  in future brakes later and/or less intensely and as a consequence travels further with the result that a position is reached in which the two sensors  12 ,  13  obtain a measurement value in the value range  14 . 
       FIG. 13  illustrates a third exemplary embodiment for a gap measurement by means of a first and a second sensor  12 ,  13  and a gap profile  10  in a trapezoid shape. In this case, the second sensor  13  is in the value range  16  and the first sensor is in the value range  14 . This means that the stopping point is still sufficiently precise with the result that the doors  2  of the vehicle may open when the vehicle  1  is at a standstill. However, a correction or calibration of the braking curve of the vehicle  1  should be performed so that the vehicle  1  in future brakes earlier and/or more intensely and as a consequence does not travel as far with the result that a position is reached in which the two sensors  12 ,  13  obtain a measurement value in the value range  14 . Provided therefore that one of the sensors  12 ,  13  is in the value range  15  or  16  and the other sensor  12 ,  13  is in the value range  14 , the stopping point of the vehicle  1  has namely still been reached sufficiently precisely but a correction or calibration of the braking curve of the vehicle  1  is to be performed. 
       FIG. 14  illustrates a fourth exemplary embodiment for a gap measurement by means of a first and a second sensor  12 ,  13  and a gap profile  10  in a trapezoid shape. In this exemplary embodiment, the vehicle  1  has reached the stopping point far too early with the result that the first sensor  12  is in the value range  17  and the second sensor is in the value range  14 . In the present case, the stopping point has no longer been reached sufficiently precisely with the result that the vehicle may not open the doors  2  in this position. The vehicle must therefore change its position in such a manner that at least one sensor  12 ,  13  is in the value range  14  and the other sensor  12 ,  13  is in the value range  15  or  16  so that the doors  2  of the vehicle  1  may be opened. Moreover, a correction or calibration of the braking curve of the vehicle  1  must be performed so that the vehicle  1  in future brakes later and/or less intensely and as a consequence travels further with the result that a position is reached in which the first sensor  12  is not allocated a measurement value in the value range  17 . 
       FIG. 15  illustrates a fifth exemplary embodiment for a gap measurement by means of a first and a second sensor  12 ,  13  and a gap profile  10  in a trapezoid shape. In this exemplary embodiment, the vehicle  1  has reached the stopping point far too late with the result that the first sensor  12  is in the value range  14  and the second sensor is in the value range  18 . In the present case, the stopping point has no longer been reached sufficiently precisely with the result that the vehicle  1  may not open the doors  2  in this position. The vehicle  1  must therefore change its position in such a manner that at least one sensor  12 ,  13  is in the value range  14  and the other sensor  12 ,  13  is in the value range  15  or  16  so that the doors  2  of the vehicle  1  may be opened. Moreover, a correction or calibration of the braking curve of the vehicle  1  must be performed so that the vehicle  1  in future brakes earlier and/or more intensely and as a consequence does not travel as far with the result that a position is reached in which the second sensor  13  is not allocated a measurement value in the value range  18 . Provided therefore that at least one sensor  12 ,  13  is in the value range  17  or  18 , the stopping point has no longer been reached sufficiently precisely by the vehicle  1 , with the result that the doors  2  of the vehicle  1  may not be opened and moreover a correction or calibration of the braking curve of the vehicle  1  is required. 
       FIG. 16  illustrates a first exemplary embodiment of a gap profile  10  in a trapezoid shape in which the ascending and the descending flanks of the gap profile  10  that is embodied as a trapezoid have a straight extent. An extent of this type has the advantage that the gap profile  10  is simple to produce. However, the straight extent could sometimes lead to the fact that owing to the smooth surface the sensor of the sensor unit that is provided for the detection of the gap may perform an incorrect detecting procedure. 
       FIG. 17  illustrates a second exemplary embodiment of a gap profile  10  in a trapezoid shape in which the ascending and the descending flanks of the gap profile  10  that is embodied as a trapezoid has a stepped extent. An extent of this type has the advantage that it is possible to use more cost-effective sensors of the sensor unit which sometimes have problems with the detection of smooth oblique surfaces. 
     Accordingly, an evaluation is performed by way of the system in accordance with the invention by way of analogue measurement values that are detected by means of gap measurement by sensors  12 ,  13 , as a result of which a reliable detection of the absolute stopping point accuracy that is achieved during operation and an optimizing procedure of the stopping point accuracy is rendered possible using signal technology by way of an automated correction of the braking curve. 
     Although the invention has been further illustrated and described in detail by way of preferred exemplary embodiments, the invention is not limited in this manner by the examples that are disclosed and other variations may be derived therefrom by the person skilled in the art without departing from the protective scope of the invention.