DISTANCE MEASURING OPTOELECTRONIC SAFETY SENSOR AND METHOD OF MONITORING A MONITORED ZONE

• US 20110273723A1
• Filed: 04/15/2011
• Published: 11/10/2011
• Est. Priority Date: 05/04/2010
• Status: Active Grant

• Current Assignee: Sick AG (Sick)
• Original Assignee: Sick AG (Sick)
• Inventors: ROTHENBERGER, Bernd, HABERER, Manfred
• Granted Patent: US 8,933,593 B2
• Time in Patent Office: Days
• US Class Current: 356/614
• CPC Class Codes: F16P 3/14 the means being photocells or other devices sensitive without mechanical contact
• CPC Class Codes: F16P 3/144 using light grids
• CPC Class Codes: G01S 17/04 Systems determining the presence of a target
• CPC Class Codes: G01S 17/42 Simultaneous measurement of distance and other co-ordinates indirect measurement G01S17/46
• CPC Class Codes: G01S 17/87 Combinations of systems using electromagnetic waves other than radio waves
• CPC Class Codes: G01S 7/4817 relating to scanning

Abstract

A distance measuring optoelectronic safety sensor (10) for monitoring a monitored zone (18) having at least one protected zone (48) is provided, wherein the safety sensor (10) has a light receiver (24) for generating a received signal on light reception from the monitored zone (18) as well as an evaluation unit (30, 32) which is designed to detect objects (52) in the monitored zone (18) with the aid of the received signal and to determine their position, including their distance from the safety sensor (10), and to output a securing signal on recognition of an unpermitted object intrusion (52) into a protected zone (48). In this respect, the evaluation unit (30, 36) is designed to determine and output the distance of detected objects (52) from the protected zone (48).

Claims

1. A distance measuring optoelectronic safety sensor (10) for monitoring a monitored zone (18) having at least one protected zone (48), wherein the safety sensor (10) has a light receiver (24) for generating a received signal on light reception from the monitored zone (18) as well as an evaluation unit (30, 32) which is designed to detect objects (52) in the monitored zone (18) with the aid of the received signal and to determine their position, including their distance from the safety sensor (10), and to output a securing signal on recognition of an unpermitted object intrusion (52) into a protected zone (48),

characterised in that

the evaluation unit (30, 36) is designed to determine and output the distance of detected objects (52) from the protected zone (48).

2. A safety sensor (10) in accordance with claim 1,

wherein the protected zone (48) is a two-dimensional protected field whose boundary can be defined for the evaluation unit (30) with reference to sampling points (50) and to curve series, in particular as a polygon series, connecting the sampling points (50).

3. A safety sensor (10) in accordance with claim 2,

wherein the evaluation unit (30) is designed to determine and output the distance of detected objects (52) from the protected zone (48) only once per curve series and/or only once per sampling point (50).

4. A safety sensor (10) in accordance with claim 2,

wherein the evaluation unit (30) is designed to add further sampling points (50) to the samplings points (50) automatically or to remove sampling points (50) automatically.

5. A safety sensor (10) in accordance with claim 1,

wherein changes in the position of sampling points (50), new sampling points (50) and/or sampling points (50) to be removed can be defined for the evaluation unit (30) during the ongoing securing operation so that the evaluation unit (30) thereupon continues to work with the thus newly generated protected zone (48).

6. A safety sensor (10) in accordance with claim 1,

wherein the protected zone is a three-dimensional protected area zone whose boundary can be defined for the evaluation unit (30) using a triangular net, with the evaluation unit (30) in particular being designed to output the spacing of detected objects (52) from the protected area zone only once per triangle, or with additional or amended triangles or triangles to be removed being able to be defined for the evaluation unit (30) during the ongoing securing operation.

7. A safety sensor (10) in accordance with claim 1,

wherein the evaluation unit (30) is designed to output speeds at which objects (52) approach the protected zone (48) or move away from the protected zone (48).

8. A safety sensor (10) in accordance with claim 1,

wherein the evaluation unit (30) is designed to treat at least one protected zone (48) as a mute protected zone (60) and thus to treat it as a purely measuring zone in which no evaluation for unpermitted object intrusions (52) takes place for the mute protected zone (60).

9. A safety sensor (10) in accordance with claim 1,

which is a 3D camera, a distance measuring safety laser scanner or a scanning light grid.

10. A system of at least two optoelectronic safety sensors (10a-b) in accordance with any one of the preceding claims claim 1, wherein the evaluation unit (30, 58) is designed to convert the perspectives of the safety sensors (10a-b) into one another.

11. A system in accordance with claim 10,

wherein the evaluation unit (30, 58) is designed to distribute the protected zones (48) over the safety sensors (10a-b) so that no securing gaps arise.

12. A method for the monitoring of a monitored zone (18) having at least one protected zone (48), wherein light from the monitored zone (18) is converted in a safety sensor (10) into a received signal, objects (52) in the monitored zone (18) are detected with the aid of the received signal, their position, including their distance from the safety sensor (10), is determined and, on recognition of an unpermitted object intrusion (52) into a protected zone (48), a securing signal is output, characterised in that

the distance of detected objects (52) from the protected zone (48) is determined and output.

13. A method in accordance with claim 12,

wherein the protected zone (48) is a two-dimensional protected field whose boundary is defined with reference to sampling points (50) and by curve series connecting the sampling points (50), wherein the distance of detected objects (52) from the protected zone (48) are only determined and output once per curve series and/or only once per sampling point (50).

14. A method in accordance with claim 13,

wherein dynamically changed protected zones (48) are defined for the safety sensor (10 during the ongoing securing operation by instructions to change the position of sampling points (50), to add new sampling points (50) or to remove existing sampling points (50).

15. A method in accordance with claim 12,

wherein at least one protected zone (60) is treated as a mute protected zone and thus purely as a measuring zone in that only distances of detected objects (52) from the protected zone (48) are determined and output for the mute protected zone (60), but unpermitted object intrusions (52) are not recognised so that an intrusion into a mute protected zone (60) does not result in a securing signal.