Machine safety system with mutual exclusion zone

• US 20020186299A1
• Filed: 06/08/2001
• Published: 12/12/2002
• Est. Priority Date: 06/08/2001
• Status: Active Grant

• Current Assignee: Honeywell Incorporated (Honeywell International Inc.)
• Original Assignee: Honeywell Incorporated (Honeywell International Inc.)
• Inventors: Cofer, Darren Duane
• Granted Patent: US 7,768,549 B2
• Time in Patent Office: Days
• US Class Current: 348/152
• CPC Class Codes: F16P 3/142 using image capturing devices

Abstract

A safety system receives access monitoring information from sensors to detect intrusion into a mutual exclusion zone by either an operator or mechanical equipment. The border of the mutual exclusion zone is segmented into portals that allow both the operator and equipment to access a common work area such as for loading material. When intrusion into one of the portals is detected, intrusion into any other selected portals triggers a safety violation. Access to the mutual exclusion zone via the other portals is prohibited until the interior of the zone is determined to be empty again.

Claims

1. A mutual exclusion mechanism for an operator operated hazardous machine, the mechanism comprising:

a sensor that detects entrance of one of the operator or portion of the machine into segments bordering a mutual exclusion zone; and

a controller that receives information from the sensor regarding entrance into the mutual exclusion zone, and controls the machine based on entrance of a second of the operator or portion of the machine into another segment of the mutual exclusion zone.

2. The mutual exclusion mechanism of claim 1 wherein the sensor comprises multiple sensors.

3. The mutual exclusion mechanism of claim 1 wherein the sensor comprises a safety camera.

4. The mutual exclusion mechanism of claim 1 wherein the sensor also detects the presence of one of the operator or portion of the machine within the mutual exclusion zone.

5. The mutual exclusion mechanism of claim 1 wherein the controller generates a trigger list of further segments when one of the operator and portion of the machine have entered the mutual exclusion zone via one segment.

6. The mutual exclusion mechanism of claim 5 wherein entrance by a second of the operator or portion of the machine into a segment on the trigger list results in generation of a safety violation.

7. The mutual exclusion mechanism of claim 5 wherein some segments are on the trigger list prior to any segment being entered.

8. The mutual exclusion mechanism of claim 1 wherein the sensor also detects the presence of one of the operator or portion of the machine within the mutual exclusion zone, the controller generates a trigger list of further segments when one of the operator and portion of the machine have entered the mutual exclusion zone via one segment, and wherein entrance by a second of the operator or portion of the machine into a segment on the trigger list results in generation of a safety violation.

9. The mutual exclusion mechanism of claim 1 wherein the controller tracks multiple states of the mutual exclusion zone selected from the group consisting of safe, empty and unsafe.

10. A method for detecting an object entering a region while the region is occupied by one or more other objects, the method comprising:

defining a border of a region of interest;

defining segments of the border through which access to the region is permitted;

determining when a segment of the border has been crossed;

determining when the interior of the region is occupied; and

upon determining that an object has entered the region of interest while the region is occupied, indicating that an object has been detected.

11. The method of claim 10 wherein a mutual exclusion analysis function determines a set of border segments through which access to the region is permissible.

12. The method of claim 11 wherein the mutual exclusion analysis function determines the set of border segments through which access to the region is permissible based on which segment of the border has already been accessed.

13. The method of claim 12 wherein after the region has been accessed, the set of border segments through which further access to the region is permissible consists only of the segment through which the region has already been accessed.

14. The method of claim 12 wherein the mutual exclusion analysis function restores the set of border segments through which access to the region is permissible to its initial state based on determining that the interior of the region is no longer occupied.

15. The method of claim 11 wherein the border crossing and interior presence determinations are made using a safety camera.

18. The method of claim 17 wherein the signal comprises a stop machine signal or a safety warning signal.

16. A method of controlling a machine, the method comprising:

detecting whether an operator or machine have entered a mutual exclusion zone;

monitoring whether one of the operator or machine are still in the mutual exclusion zone; and

if one of the operator or machine are still in the mutual exclusion zone, controlling the machine based on the entrance of the other of the operator or machine into the mutual exclusion zone.

17. A method of detecting a hazardous condition for an operator of a machine, the method comprising:

monitoring a mutual exclusion zone proximate the machine;

detecting whether an operator or machine have entered the mutual exclusion zone;

monitoring whether one of the operator or machine are still in the mutual exclusion zone; and

if one of the operator or machine are still in the mutual exclusion zone, generating a signal based on the entrance of the other of the operator or machine into the mutual exclusion zone.

19. A method of defining a hazardous zone for an operator of a machine, the method comprising:

defining multiple segments bordering the hazardous zone; and

defining a trigger list for each segment, such that entry by one of the operator or machine into a segment activates the corresponding trigger list while the one of the operator or machine is still present within the hazardous zone.