Device for Measuring the Movement of a Self-Guided Vehicle

• US 20100324776A1
• Filed: 12/10/2007
• Published: 12/23/2010
• Est. Priority Date: 12/10/2007
• Status: Active Grant

• Current Assignee: Siemens Mobility SAS (Siemens AG)
• Original Assignee: Siemens Transportation Systems SAS (Siemens AG)
• Inventors: Maire, Alain
• Granted Patent: US 8,423,234 B2
• Time in Patent Office: Days
• US Class Current: 701/33
• CPC Class Codes: B60T 8/1705 for rail vehicles
• CPC Class Codes: B60T 8/172 Determining control parameters used in the regulation, e.g. by calculations involving measured or detected parameters B60T8/17551 takes precedence
• CPC Class Codes: B61L 25/021 Measuring and recording of train speed

Abstract

The invention relates to a device for measuring the movement of a self-guided vehicle, that comprises onboard thereof: at least one accelerometer provided with a measurement axis arranged in the longitudinal direction of a potential main rectilinear movement of the vehicle, a first tachometer provided on an axle upstream from the vehicle in the longitudinal direction, a second tachometer provided on a second axle downstream from the vehicle in the longitudinal direction, wherein measure signals from the accelerometer and from the first and second tachometers are supplied to a computing unit. Accordingly, it is advantageously possible to determine the speed and the position of the vehicle on a vehicle route while taking into account an adhesion loss of at least one of the axles as well as an exact slope and turn effect on a vehicle route that does not remain rectilinear and changes horizontally and/or vertically.

Claims

1. A device for measuring the movement of a self-guided vehicle (VEH) comprising on-board thereof:

at least one accelerometer (101) provided with a measurement axis in the longitudinal direction (VEx) of a main movement of the vehicle, assumed to be rectilinear,

a first tachometer (103b) provided on an axle upstream from the vehicle in the longitudinal direction,

a second tachometer (103a) is provided on a second axle downstream from the vehicle in the longitudinal direction,

measurement signals from the accelerometer and from the first and second tachometers are supplied to a computing unit, characterized in that in the event of detection of adhesion loss;

a system for position measurement (DB) supplies data of a profile of the trajectory of the vehicle such as at least one slope (Pte) and one turn (1/R) at each position (DX) of the vehicle in motion,

the accelerometer provided with a measurement axis provides a measurement of a total acceleration (Gacc) of the vehicle in the longitudinal direction (VEx),

a computer (CALC) processes the data of the profile of the trajectory (Pte, 1/R) and the total acceleration measured (Gacc) in order to determine a corrected acceleration (Gx) in a longitudinal direction (Ox) of effective movement of the vehicle for which the effects of slope and turn are taken into account.

2. The device as claimed in claim 1, comprising:

a detector of adhesion loss (CALC1) of at least one of the two axles,

the detector of adhesion loss being coupled to output signals (STa, STb) of each of the tachometers,

each output signal providing a measurement of instantaneous angular speed of the associated axle.

3. The device as claimed in claim 2, in which the detector of adhesion loss (CALC1) comprises an indicator (Adh) of two modes of detection of adhesion loss which may be combined, according to which a variation of instantaneous angular speed of at least one of the output signals is detected or/and a difference between the angular speeds of each output signal is detected.

4. The device as claimed in claim 3, in which the computer (CALC) comprises:

a primary computer (CALC2) provided with signal inputs for the data of the profile of the trajectory (Pte, 1/R) and for the measured acceleration (Gacc) and a signal output for the corrected acceleration (Gx),

a secondary computer (CALC3) provided with a signal input for the indicator (Adh) for detecting adhesion loss from the detector of adhesion loss (CALC1),

the secondary computer (CALC3) being provided with outputs for supplying an estimated speed (Vx) and an estimated position (Dx) of the vehicle,

the secondary computer (CALC3) being provided with inputs for the signals (STa, tachometers to estimate the speed (Vx) and the position (Dx) of the vehicle—

the secondary computer (CALC3) being provided with a signal input for the corrected acceleration (Gx) from the primary computer (CALC2) in order to re-estimate the speed (Vx) and the position (Dx) of the vehicle at least during an adhesion loss for which a previously estimated value of the speed (Vx) is transmitted from the secondary computer (CALC3) to the primary computer (CALC2) to carry out a re-estimation of the corrected acceleration (Gx).

5. The device as claimed in claim 3, in which:

the corrected acceleration (Gx) is the sum of the total measured acceleration (Gacc), the acceleration under the effect of slope (Gpte) and the acceleration under the effect of turn (Glat),

the acceleration under the effect of slope (Gpte) is proportional to gravity,

the acceleration under the effect of turn (Glat) is the product of;

a) a sine of an instantaneous angle (A) of which the apex is at the center of curvature (1/R) and of which the sides pass through the center of the vehicle and through the accelerometer

b) and the speed (Vx) squared and divided by the sum of a radius (R) of curvature (1/R) and a lateral distance (Ly) of the accelerometer relative to the center of the vehicle,

the instantaneous angle (A) is approximated by a longitudinal distance (Lx) of the accelerometer relative to the center of the vehicle divided by the sum of the radius of curvature (R) and the lateral distance (Ly) of the accelerometer relative to the center of the vehicle.

where the longitudinal distance (Lx) is positive or negative according to whether the accelerometer is arranged upstream or downstream from the vehicle in its direction of movement and the lateral distance (Ly) is positive or negative according to whether the accelerometer is arranged on the outside or inside of a curve relative to the turn (1/R).

6. The device as claimed in one of the preceding claims 3 to 5, in which before a detection of adhesion loss, the secondary computer (CALC3) supplies the speed (Vx) and the position (Dx) of the vehicle by means of dynamic parameters associated with the rotation of at least one of the axles.

7. The device as claimed in claim 6, in which during an adhesion loss the secondary computer (CALC3) supplies the speed (Vx) to the primary computer (CALC2), said primary computer supplying in return the acceleration (Gx) to the secondary computer (CALC3).

8. The device as claimed in one of the preceding claims 3 to 7, in which the accelerometer comprises a plurality of separate measurement axes (in order to refine the determination of the corrected acceleration (Glong) and/or to compensate for a loss of information from the system for measuring position, providing the odometric data).

9. The device as claimed in one of the preceding claims 4 to 8, wherein the accelerometer comprises a plurality of separate axes (in order to refine the determination of the corrected acceleration (Glong) and/or to compensate for a loss of information from the positioning measurement system providing the odometric data).