US 12,290,939 B2
Sensor arrangement and method for safeguarding a monitored zone
Markus Hammes, Waldkirch (DE); and Nicolas Löffler, Waldkirch (DE)
Assigned to SICK AG, Waldkirch (DE)
Filed by SICK AG, Waldkirch (DE)
Filed on Aug. 2, 2022, as Appl. No. 17/879,555.
Claims priority of application No. 21189252 (EP), filed on Aug. 3, 2021.
Prior Publication US 2023/0081003 A1, Mar. 16, 2023
Int. Cl. B25J 9/16 (2006.01); B25J 13/08 (2006.01); G01S 13/86 (2006.01); G01S 13/88 (2006.01); G06T 7/246 (2017.01); G06V 20/52 (2022.01); H04N 5/77 (2006.01); H04N 7/18 (2006.01)
CPC B25J 9/1676 (2013.01) [B25J 13/08 (2013.01); G01S 13/867 (2013.01); G01S 13/88 (2013.01); G06T 7/248 (2017.01); G06V 20/52 (2022.01); H04N 5/77 (2013.01); H04N 7/183 (2013.01); G06T 2200/04 (2013.01); G06T 2207/10012 (2013.01); G06T 2207/10028 (2013.01); G06T 2207/30196 (2013.01); G06T 2207/30232 (2013.01)] 15 Claims
OG exemplary drawing
 
1. A sensor arrangement for safeguarding a monitored zone at a machine that defines a hazard site, the sensor arrangement comprising
at least one camera configured to continuously generate 3D images for the detection of objects in the monitored zone;
a control and evaluation unit configured to determine the presence or position of detected objects in the monitored zone and to initiate a safety-directed response of the machine in the case of a hazardous position;
a buffer memory unit configured to store the generated 3D images therein;
the control and evaluation unit is configured to prepare a 3D reference map from the stored 3D images when the safety-directed response has been initiated;
a voxel identification unit configured to flag voxels in a current 3D image, from among the 3D images generated continuously after the safety-directed response has been initiated, whose coordinates differ by a specified distance from coordinates of corresponding voxels of the 3D reference map; and
a movement recognition unit in which the flagged voxels are examined to determine whether they display a position change in the 3D images generated continuously after the safety-directed response has been initiated that is above a fixed threshold value; and
wherein the control and evaluation unit is configured to output a restart signal for the machine in response to the movement recognition unit determining that the position change is equal to or below the fixed threshold value.