Piezoelectric sensor module of a WIM system for two-track vehicles and measurement method

Patent metadata

Field	Value
Publication number	US-9488517-B2
Application number	US-201314400928-A
Country	US
Kind code	B2
Filing date	May 15, 2013
Priority date	May 16, 2012
Publication date	Nov 8, 2016
Grant date	Nov 8, 2016

Abstract

A sensor module for measuring axle speeds and weights of double-track vehicles which travel in a direction of travel (L) along a carriageway with two lanes includes a plurality of piezoelectric strip sensors (A, B, C, D) that are arranged in a first lane group (I) and a second lane group (II). All the strip sensors (A, B, C, D) are spaced from each other in the direction of travel (L) via a secure longitudinal offset (LAD), which is greater than the maximum wheel contact length, and are offset from one another by between one centimeter and fifteen centimeters in the transversal direction. The sensor module also has a module length (LABCD) of less than 80 centimeters.

First claim

The invention claimed is:

1. Sensor module for measuring the axle speeds and weights of two-track vehicles, which travel in a direction of travel (L) along a roadway with two lanes, comprising a plurality of piezoelectric strip sensors (A, B, C, D), wherein all the strip sensors (A, B, C, D) have axial centerlines that are arranged orthogonally (Q) to the direction of travel (L), wherein a first strip sensor and a second strip sensor in a first pair of strip sensors (A, D) are spaced from each other in the direction of travel (L) in a first lane group of the sensor module via a first fixed longitudinal offset (LAD) which is greater than the maximum wheel contact length, wherein a first strip sensor (B) and a second strip sensor (C) in a second pair of strip sensors (B, C) are spaced from each other in the direction of travel (L) in a second lane group of the sensor module via a second fixed longitudinal offset (LBC) which is greater than the maximum wheel contact length, wherein the strip sensors (A, D) of the first lane group are arranged with an offset from the strip sensors (B, C) of the second lane group transversely (Q) to the direction of travel (L), so that each lane group covers a separate lane of the roadway, wherein the first strip sensor (A) of the first lane group and the first strip sensor (B) of the second lane group are arranged with an offset between 1 and 15 cm relative to each other in the direction of travel, wherein the second strip sensor (D) of the first lane group and the second strip sensor (C) of the second lane group are arranged with an offset (LAB or LCD) between 1 cm and 15 cm relative to each other in the direction of travel, and the sensor module has a module length (LABCD) less than 80 cm in the direction of travel.

2. Sensor module according to claim 1 , wherein the distance (LAB) of the offset between the first strip sensors (A, B) in the direction of travel (L) is greater than 1 cm and less than 8 cm and wherein the distance (LCD) of the offset between the second strip sensors (C, D) of the different lane groups in the direction of travel (L) is greater than 1 cm and less than 8 cm.

3. Sensor module according to claim 1 , wherein each of the longitudinal offsets (LAD, LBC) is greater than 20 cm.

4. Sensor module according to claim 1 , wherein the strip sensors (A, D) of the first lane group are arranged relative to the strip sensors (B, C) of the second lane group in such manner that all strip sensors (A, B, C, D) are arranged completely separately and with no overlap in the direction of travel (L) and with no overlap in the direction transverse (Q) to the direction of travel (L).

5. Sensor module according to claim 1 , wherein the longitudinal offset (LAD) of the first lane group is greater than the longitudinal offset (LBC) of the second lane group.

6. Sensor module according to claim 1 , wherein the longitudinal offset (LAD) of the first lane group is equal to the longitudinal offset (LBC) of the second lane group.

7. Sensor module according to claim 1 , wherein the sensor module is formed by a frame construction, in which the strip sensors (A, B, C, D) of the first lane group and of the second lane group are mounted with fixed intervals relative to each other.

8. Sensor module according to claim 7 , wherein the frame construction comprises at least two frame sections, in which either the strip sensors (A, D) of the first lane group and the second (B, C) lane group are fastened separately, or in which each of the first strip sensors (A, B) and the second strip sensors (C, D) are mounted separately.

9. Sensor module according to claim 7 , wherein at least one of an electronic signal acquisition unit and an evaluation unit is secured in the frame structure.

10. Sensor module ( 1 ) according to claim 7 , wherein an output wire is routed from the frame structure and electrically connected so that it forwards bundled measurement signals from all the strip sensors (A, B, C, D).

11. Sensor module for measuring the axle speeds and weights of two-track vehicles, which travel in a direction of travel (L) along a roadway with two lanes, comprising:
a plurality of piezoelectric strip sensors (A, B, C, D), wherein all the strip sensors (A, B, C, D) have axial centerlines that are arranged orthogonally (Q) to the direction of travel (L), wherein a first strip sensor and a second strip sensor in a first pair of strip sensors (A, D) are spaced from each other in the direction of travel (L) in a first lane group of the sensor module via a first fixed longitudinal offset (LAD) which is greater than the maximum wheel contact length, wherein a first strip sensor (B) and a second strip sensor (C) in a second pair of strip sensors (B, C) are spaced from each other in the direction of travel (L) in a second lane group of the sensor module via a second fixed longitudinal offset (LBC) which is greater than the maximum wheel contact length, wherein the strip sensors (A, D) of the first lane group are arranged with an offset from the strip sensors (B, C) of the second lane group transversely (Q) to the direction of travel (L), so that each lane group covers a separate lane of the roadway, wherein the first strip sensors (A) of the first lane group and the first strip sensor (B) of the second lane group are arranged with an offset between 1 and 15 cm relative to each other in the direction of travel, wherein the second strip sensors (D) of the first lane group and the second strip sensor (C) of the second lane group are arranged with an offset (LAB or LCD) between 1 cm and 15 cm relative to each other in the direction of travel, and the sensor module has a module length (LABCD) less than 80 cm in the direction of travel;
wherein the sensor module is formed by a frame construction, in which the strip sensors (A, B, C, D) of the first lane group and of the second lane group are mounted with fixed intervals relative to each other; and
wherein a toothed structure is fastened to at least one surface before or after the frame structure in the direction of travel (L).

12. Sensor module according to claim 11 , wherein the toothed structure is positioned at the level of a road surface.

13. Sensor module according to claim 1 , wherein the first strip sensor (A) of the first lane group and the first strip sensor (B) of the second lane group are arranged edge to edge in a direction (Q) transverse to the direction of travel (L).

14. Sensor module according to claim 1 , wherein the plurality of strip sensors includes more than four strip sensors (A, B, C, D) and the strip sensors in excess of four strip sensors are arranged additionally to improve the accuracy of the results.

15. Method for dynamically measuring the weight of vehicles travelling on a roadway, wherein a sensor module comprising a plurality of strip sensors (A, B, C, D) is used, wherein all the strip sensors (A, B, C, D) have axial centerlines that are arranged orthogonally (Q) to the direction of travel (L), wherein a first strip sensor (A) and a second strip sensor (D) in a first pair of strip sensors are spaced from each other in the direction of travel (L) in a first lane group of the sensor module via a first fixed longitudinal offset (LAD) which is greater than the maximum wheel contact length, wherein a first strip sensor (B) and a second strip sensor (C) in a second pair of strip sensors are spaced from each other in the direction of travel (L) in a second lane group of the sensor module via a second fixed longitudinal offset (LBC) which is greater than the maximum wheel contact length, wherein the strip sensors (A, D) of the first lane group are arranged with an offset fr

Assignees

• Kistler Holding Ag

Inventors

• Cornu David
• Hofmann Adrian

Classifications

• G08G1/052

  with provision for determining speed or overspeed {(speed measuring in general G01P)} · CPC title

• G08G1/02

  using treadles built into the road (pads or other sensitive devices responsive to passage of vehicles E01F11/00) · CPC title

• G01G19/024 Primary

  using electrical weight-sensitive devices · CPC title

• G01P3/50

  for measuring linear speed (G01P3/56 takes precedence) · CPC title