The Second Generation (G2) Fingertip Sensor for Near-Distance Ranging and Material Sensing in Robotic Grasping*

To continuously improve robotic grasping, we are interested in developing a contactless fingertip-mounted sensor for near-distance ranging and material sensing. Previously, we demonstrated a dual-modal and dual sensing mechanisms (DMDSM) pretouch sensor prototype based on pulse-echo ultrasound and optoacoustics. However, the complex system, the bulky and expensive pulser-receiver, and the omni-directionally sensitive microphone block the sensor from practical applications in real robotic fingers. To address these issues, we report the second generation (G2) DMDSM sensor without the pulser-receiver and microphone, which is made possible by redesigning the ultrasound transmitter and receiver to gain much wider acoustic bandwidth. To verify our design, a prototype of the G2 DMDSM sensor has been fabricated and tested. The testing results show that the G2 DMDSM sensor can achieve better ranging and similar material/structure sensing performance, but with much-simplified configuration and operation. The primary results indicate that the G2 DMDSM sensor could provide a promising solution for fingertip pretouch sensing in robotic grasping.