An Ultra-Fast Intrinsic Contact Sensing Method for Medical Instruments with Arbitrary Shape

Intraoperative contact sensing has the potential to Q1 Q2 4 reduce the risk of surgical errors and enhance manipulation ca- 5 pabilities for medical robots, particularly in contact force con- 6 trol. Current intrinsic force sensing (IFS) methods are limited 7 in application to medical instruments with arbitrary shape, due 8 to high computational time and reliance on surface equations. 9 This study presents an ultra-fast IFS method that uses multiple 10 planes to establish surface geometry descriptions. The method 11 can reduce high-order contact mechanical models that need to 12 be solved iteratively to a set of linear equations, and calculate 13 contact location analytically. In addition, a robot motion control 14 approach based on the contact sensing method is proposed to 15 maintain stable contact force and regulate the probe’s orientation 16 for robotic ultrasound systems (RUSS). Experimental results show 17 that the contact sensing method is robust to friction and can achieve 18 a mean (±SD) displacement error of 1.04 ± 0.43 mm in contact 19 location with computational time less than 1 ms. The system has 20 been evaluated on a phantom with sinusoidal motion. To the best 21 of our knowledge, this is the first study to validate adaptiveness 22 of RUSS under dynamic conditions. The results demonstrated 23 that the system exhibits comparable manipulation capabilities to 24 human operators with only force sensing, indicating a high level of 25 adaptiveness. 26