Jason T. Wilson

Assessment of a Hexapod Surgical System for Robotic Micro-Macro Manipulations in Ocular Surgery

Purpose: Robotic intraocular microsurgery requires a remote center of motion (RCM) at the site of ocular penetration. We designed and tested the Hexapod Surgical System (HSS), a microrobot mounted on the da Vinci macrorobot for intraocular microsurgery. Material and Methods: Translations and rotations of the HSS were tested for range of motion and stability. Precision and dexterity were assessed by pointing and inserting a coupled probe into holes of various sizes. The stability of a nonmechanical RCM was quantified. HSS functionalities were observed on porcine eyes. Results: The HSS maximal translations were 10 (x and y axes) and 5 cm (z axis). The maximal rotations were 15 and 22° (x and y axes). The precision was within 0.5 mm away from targets in 26/30 tests and maximal in 16/30 tests. The mean translational and rotational stability at the tip of the probe were 1.2 (0.6–1.9) and 1 mm (0–2), respectively. The average dexterity times were 5.2 (4.4–6.5), 7.1 (5.6–10.8) and 12.3 s (7.8–21.7) for 5-, 2- and 1-mm holes, respectively. The RCM was stable (within 0.1 mm). A vitreous cutter coupled to the HSS moved into porcine eyes through a sclerotomy with a stable RCM. Conclusion: The HSS provides an RCM dedicated for intraocular robotic surgery with a high level of precision and dexterity. Although it can be further improved, the micro-macro robotic system is a feasible approach for ocular surgery.

Modeling and control of a magnetic bearing system

This paper presents the pedagogy of digital control design and experiment for a magnetic bearing system as part of a graduate level digital control class. The system identification verifies the system model structure, where the unstable MIMO system is kinematically de-coupled into SISO systems with model uncertainty bounds characterized for robustness analysis. Low order SISO plant models are used for control design while a high order MIMO model is used for verification before the implementation. Following a simple lead compensator, model based control design, analysis, verification, and implementation include state estimator feedback control and its augmentation with integrator and oscillator internal models; all stabilizing control and minimum variance control; approximate plant inversion for feedfoward tracking and repetitive control.

Robotic Eye Surgery

Ophthalmology is a field at the forefront of innovation. Improvements in surgical instrumentation and refinements in surgical techniques have resulted in improved outcomes while decreasing operating time. Digital ultrahigh definition microscope utilization, real-time overlays of intraoperative OCT data, and automated laser assisted cataract surgery have been recent major contributions to our field. We believe the next revolution in ophthalmology will be the further development and acceptance of robotics.

Evaluating remote centers of motion for minimally invasive surgical robots by computer vision

This paper addresses the measurement of the location and precision of stationary points in the three dimensional space, commonly termed remote center of motion (RCM), of minimally invasive surgical robotic manipulators. Two-view computer vision is used for its versatility, portability, remote sensing, and cost effectiveness. Geometrical models of cylindrical tools are constructed from camera images. The RCM is computed from the vectors of the cylindrical tool center lines at multiple poses. To verify the approach, a gold standard spherical bearing is first used to measure the RCM location and precision. The same computer vision system and RCM method is then applied to evaluate the RCM of a commercially available laparoscopy surgical robot.

Intraocular robotic interventional surgical system (IRISS): Mechanical design, evaluation, and master–slave manipulation

Background: Since the advent of robotic‐assisted surgery, the value of using robotic systems to assist in surgical procedures has been repeatedly demonstrated. However, existing technologies are unable to perform complete, multi‐step procedures from start to finish. Many intraocular surgical steps continue to be manually performed.

Design and Control of Fast Tool Servo for Boring of Engine Piston Pin Holes

This paper presents the mechanical and servo control design of a fast tool servo for machining noncircular bores. The rotating boring bar varies the depth of cut dynamically to machine noncircular bores, such as those in engine piston gudgeon pin holes. The piezoelectric actuator driven fast tool servo has 60 micron displacement and about 400 Hz first natural frequency. The design of robust repetitive control of the fast tool servo is discussed and experimental results of cutting tool motion for generating oval bore profiles are presented.Copyright