US 12,304,085 B2
Cliff detection in robotic devices
Benoit Rivot, Bessy (FR); and Xingyu Wang, Shenzhen (CN)
Assigned to STMicroelectronics (Shenzhen) R&D Co. Ltd., Shenzhen (CN); and STMICROELECTRONICS LTD., Kowloon (HK)
Filed by STMICROELECTRONICS LTD, Kowloon (HK); and STMicroelectronics (Shenzhen) R&D Co., Ltd., Shenzhen (CN)
Filed on May 3, 2022, as Appl. No. 17/661,899.
Prior Publication US 2023/0356397 A1, Nov. 9, 2023
Int. Cl. B25J 9/16 (2006.01)
CPC B25J 9/1666 (2013.01) [B25J 9/163 (2013.01); B25J 9/1694 (2013.01)] 21 Claims
OG exemplary drawing
 
1. A method of operating a robotic device, the method comprising:
moving the robotic device towards an edge of a cliff while a time of flight (ToF) sensor senses reflected signals having been transmitted by the ToF sensor, the reflected signals being generated by signals transmitted by the ToF sensor being reflected off a target object back to the ToF sensor, the ToF sensor being attached to a front of the robotic device and comprising an array of single-photon avalanche diode (SPAD) sensors;
comparing a statistical distribution of the reflected signals received at a plurality of different rows of zones configured by the array of SPAD sensors in a region of interest (ROI) of the ToF sensor and based on the comparing detecting an approaching of the edge of the cliff, the comparing comprising identifying a convergence of an intensity of the reflected signals or of a median distance to a ground; and
in response to detecting the approaching of the edge, changing a propulsion of the robotic device before reaching the edge.