Daniel Glozman

Image-Guided Robotic Flexible Needle Steering

This paper presents a robotic system for steering under real-time fluoroscopic guidance a flexible needle in soft tissue. Given a target and possible obstacle locations, the computer calculates the flexible needle-tip trajectory that avoids the obstacle and hits the target. Using an inverse kinematics algorithm, the needle base maneuvers required for a tip to follow this trajectory are calculated, enabling a robot to perform controlled needle insertion. Assuming small displacements, the flexible needle is modeled as a linear beam supported by virtual springs, where the stiffness coefficients of the springs can vary along the needle. Using this simplified model, the forward and inverse kinematics of the needle are solved analytically, enabling both path planning and path correction in real time. The needle shape is detected in real time from fluoroscopic images, and the controller commands the needle base motion that minimizes the needle tip error. This approach was verified experimentally using a robot to maneuver the base of a flexible needle inserted into a muscle tissue. Along the 40-mm trajectory that avoids the obstacle and hits the target, the error stayed below the 0.5-mm level. This study demonstrates the ability to perform closed-loop control and steering of a flexible needle by maneuvering the needle base so that its tip achieves a planned trajectory.

Raven-II: An Open Platform for Surgical Robotics Research

The Raven-II is a platform for collaborative research on advances in surgical robotics. Seven universities have begun research using this platform. The Raven-II system has two 3-DOF spherical positioning mechanisms capable of attaching interchangeable four DOF instruments. The Raven-II software is based on open standards such as Linux and ROS to maximally facilitate software development. The mechanism is robust enough for repeated experiments and animal surgery experiments, but is not engineered to sufficient safety standards for human use. Mechanisms in place for interaction among the user community and dissemination of results include an electronic forum, an online software SVN repository, and meetings and workshops at major robotics conferences.

Flexible Needle Steering and Optimal Trajectory Planning for Percutaneous Therapies

Flexible needle insertion into viscoelastic tissue is modeled in this paper with a linear beam supported by virtual springs. Using this simplified model, the forward and inverse kinematics of the needle is solved analytically, providing a way for simulation and path planning in real-time. Using the inverse kinematics, the required needle basis trajectory can be computed for any desired needle tip path. It is shown that the needle base trajectory is not unique and can be optimized to minimize lateral pressure of the needle body on the tissue. Experimental results are provided of robotically assisted insertion of flexible needle while avoiding “obstacle”.

Design considerations of new six degrees-of-freedom parallel robots

This paper describes the structure of three types of parallel robots and compares their performances in the sense of size and static forces. The motivation for this investigation is to construct a robot that best fits a given medical application. The requirements are to cover a given work volume with a given orientation and to maintain the robot within the smallest cube possible. Among the structures examined, three are presented since two are modifications of known structures and the third is a new one.

A Self-Propelled Inflatable Earthworm-Like Endoscope Actuated by Single Supply Line

Design of a self-propelling endoscope has been of interest for decades, as it allows for simplified medical examination techniques and improved patient comfort, together with advanced analysis capacity. In this paper, we describe the development of a fully automatic, multiple-balloon system achieving peristaltic locomotion, controlled by a single supply channel. The system employs the nonlinear pressure-radius characteristics of elastic balloons to simultaneously control numerous balloons with a constant inlet pressure. The balloons are connected in series and the flow is controlled by small orifices, which delay the flow between them. The proposed multiple-balloon system requires no moving parts, no electronics, and relies on dynamics of the fluid flow between serially interconnected inflatable balloons. The entire system is made of disposable silicone and is plastic-modeled by injection molding. Additionally, the cost of such a system is expected to be low and suitable for numerous biomedical applications as it can be easily scaled down due to the need for only one supply line. Mathematical modeling, and simulation and experimental results of a system prototype are presented in this paper. Experimental results in the straight cylinder show close correlation to simulated system.

Flexible needle steering for percutaneous therapies

Objective: A robotic system is presented for flexible needle steering and control in soft tissue. Materials and Methods: Flexible needle insertion into a deformable tissue is modeled as a linear beam supported by virtual springs, where the stiffness coefficients of the springs can vary along the needle. Using this simplified model, the forward and inverse kinematics of the needle are solved analytically, thus enabling both path planning and path correction in real time. Given target and obstacle locations, the computer calculates the needle tip trajectory that will avoid the obstacle and hit the target. Using the inverse kinematics algorithm, the corresponding needle base maneuver needed to follow this trajectory is calculated. Results: It is demonstrated that the needle tip path is not unique and can be optimized to minimize lateral pressure of the needle body on the tissue. Needle steering, i.e., the needle base movements that steer the needle tip, is not intuitive. Therefore, the needle insertion procedure is best performed by a robot. The model was verified experimentally on muscle and liver tissues by robotically assisted insertion of a flexible spinal needle. During insertion, the position and shape of the needle were recorded by X-ray. Conclusions: This study demonstrates the ability to curve a flexible needle by its base motion in order to achieve a planned tip trajectory.

Plugfest 2009: Global interoperability in Telerobotics and telemedicine

Despite the great diversity of teleoperator designs and applications, their underlying control systems have many similarities. These similarities can be exploited to enable inter-operability between heterogeneous systems. We have developed a network data specification, the Interoperable Telerobotics Protocol, that can be used for Internet based control of a wide range of teleoperators. In this work we test interoperable telerobotics on the global Internet, focusing on the telesurgery application domain. Fourteen globally dispersed telerobotic master and slave systems were connected in thirty trials in one twenty four hour period. Users performed common manipulation tasks to demonstrate effective master-slave operation. With twenty eight (93%) successful, unique connections the results show a high potential for standardizing telerobotic operation. Furthermore, new paradigms for telesurgical operation and training are presented, including a networked surgery trainer and upper-limb exoskeleton control of micro-manipulators.

Novel 6-dof parallel manipulator with large workspace

The workspace of a parallel manipulator is usually smaller than the size of the robot itself. It is important to derive new structures that enjoy the advantages of parallel manipulators and also have a large workspace. In this paper we present two configurations of similar structures RRRS and RRSR with rotating links. The RRRS structure has a relatively large workspace—larger than the size of the robot itself—which is not common in parallel robots. The inverse and forward kinematics of the robots are presented. The workspaces of the robots are compared to similar and well-known structures, such as Eclipse, Alizade, Delta, and Hexa robots.

Maximizing dexterous workspace and optimal port placement of a multi-arm surgical robot

Surgical procedures are traditionally performed by two or more surgeons along with staff nurses. One surgeon serves as the primary surgeon and the other serves as his/her assistant. Surgical robotics have redefined the dynamics in which the two surgeons interact with each other and with the surgical site. Raven IV is a new generation of the surgical robot system having four articulated robotic arms in a spherical configuration, each holding an articulated surgical tool. The system allows two surgeons to teleoperate the Raven IV collaboratively from two remote sites. The current research effort aims to configure the link architecture of each robotic arm, along with the position (port placement) and orientation of the Raven IV with respect to the patient, in order to optimize the common workspace reachable by all four robotic arms. The simulation results indicate that tilting the base of the robotic arms in the range of −20 to 20 deg while moving the ports closer together up to 50 mm apart leads to a preferred circular shape of the common workspace with an isotropy value of 0.5. A carefully configured system with multiple surgical robotic arms will enhance the interactive performance of the two surgeons.

DOUBLE CIRCULAR-TRIANGULAR SIX-DEGREES-OF- FREEDOM PARALLEL ROBOT

This paper describes a new structure of a six-DOF parallel robot. First known planar three-DOF double-triangular structure is modified by replacing the stationary triangle with a circle. This increases the work envelope considerably especially when rotational motions are required. The ability for unlimited rotational motion allows extending the structure into one six-DOF by using two sets of stationary circles and moveable triangles. Each set can actuate the moving triangle in a planar three-DOF motion and hence actuate a line connecting the centers of the movable triangles in four-DOF. The robot’s end-effector is attached to a link along this line while rotation about and translation along this line are obtained by the additional rotational DOF of the movable triangles. The solution of the direct kinematics of this six-DOF manipulator is given in a closed-form and it is shown that at most, four different solutions exist.