A robotic surgical tool with continuum wrist, kinematically optimized curved stem, and collision avoidance kinematics for single port procedure

Abstract

Robot-assisted minimally invasive key-hole surgeries have thrived in recent decades, primarily robotic MPL (Multi-Port Laparoscopy) and SPL (Single Port Laparoscopy). In robotic MPL, surgical manipulators are mainly equipped with straight-stemmed tools with distal wrists. For robotic SPL, when these MPL tools and manipulators are used via a single entry, they often suffer from mutual collisions. On the other hand, dedicated SPL manipulators/tools usually lack adequate payload capabilities due to the slim multi-joint designs. To facilitate SPL, a SORST (Stem-Optimized Robotic Surgical Tool) with a continuum wrist and a kinematically optimized rigid curved stem is proposed. The SORST's curved but rigid stem can help reduce possible collisions and maintain the tool's payload capability. In this curved-stem tool, the tendon tension might be difficult to properly maintain, due to the fact that the tendon may get in contact with the guiding cannula with uncertain friction. Hence, the continuum wrist is introduced for enhancing distal dexterity. Furthermore, an instantaneous inverse kinematics framework is proposed to simultaneously avoid mutual collisions and satisfy the remote-center-of-motion constraint, joint range/velocity limits, and the desired task space twist. Extensive experimental verifications were conducted to demonstrate the efficacy.