Dynamic Active Constraints for Surgical Robots Using Vector-Field Inequalities

Abstract

Robotic assistance allows surgeons to perform dexterous and tremor-free procedures, but robotic aid is still underrepresented in procedures with constrained workspaces, such as deep brain neurosurgery and endonasal surgery. In these procedures, surgeons have restricted vision to areas near the surgical tooltips, which increases the risk of unexpected collisions between the shafts of the instruments and their surroundings. In this work, our vector-field-inequalities method is extended to provide dynamic active-constraints to any number of robots and moving objects sharing the same workspace. The method is evaluated with experiments and simulations in which robot tools have to avoid collisions autonomously and in real-time, in a constrained endonasal surgical environment. Simulations show that with our method the combined trajectory error of two robotic systems is optimal. Experiments using a real robotic system show that the method can autonomously prevent collisions between the moving robots themselves and between the robots and the environment. Moreover, the framework is also successfully verified under teleoperation with tool-tissue interactions.

Virtual Fixture Assistance for Suturing in Robot-Aided Pediatric Endoscopic Surgery

“…where the residual ζ(t) =ḋ − J dq contains the distance dynamics unrelated to the joints' velocities. The relevant functions, distance Jacobians, and residuals for all relevant primitives used in this paper are shown in [18]. Finally, the VFI method requires the definition of a safe distance d safe d safe (t) ∈ [0, ∞) and an errord d (q, t) = d − d safe to generate restricted zones ord d safe − d to generate safe zones.…”

“…In prior works, our group has focused on the generation of dynamic regional virtual fixtures to prevent collisions between tools and to generate task constraints using vector-field inequalities [18]. More recently, we applied vector-field inequalities to teleoperation tasks and developed a unified framework for teleoperation [4].…”

SmartArm: Integration and validation of a versatile surgical robotic system for constrained workspaces

“…If no constraints relating to two or more robots are required in a given task, a robot_control_node for each robot can be use. For example, constraints can be added to prevent collisions between the robots outside the patient and also to prevent collisions between instruments . For such calculations, we make extensive use of the Eigen 3 Library for linear algebra and DQ Robotics for dual‐quaternion algebra.…”

“…For example, constraints can be added to prevent collisions between the robots outside the patient and also to prevent collisions between instruments. 17 For such calculations, we make extensive use of the Eigen 3 Library § for linear algebra and DQ Robotics ¶ for dual-quaternion algebra. The linear-constrained quadratic program is solved using IMB CPLEX Optimizer with Concert Technology # .…”

“…Our group and collaborators been working in developing such a system. This endeavor represents many challenges, such as the conceptual design of the system, 14 design and fabrication of 3.5-mm-diameter dexterous tools, 15 development of an effective real-time collision-avoidance algorithm, 16,17 and development of a teleoperation algorithm. 18 In preliminary experiments, we have demonstrated that an early prototype of our robot is compatible with the high precision requirement of eye surgery 19 and the high dexterity requirement of infant surgery.…”