Peter Berkelman

Control and user interface design for compact manipulators in minimally-invasive surgery

This paper describes the control system and user command interfaces developed for a lightweight, compact, endoscope camera manipulator prototype for robot-assisted minimally invasive surgery. A complete teleoperated minimally invasive surgical system in development is also based on using lightweight, compact manipulators with simple, reliable, and robust controllers. The endoscope manipulator is controlled by a single-board computer and individual motor controllers. The single-board computer processes user commands and generates control mode and analog velocity commands for the motor controllers. A miniature keypad attached to one of the surgical instruments and a voice recognition system with a foot pedal are used as user command interfaces

Effects of Friction Parameters on Completion Times for Sustained Planar Positioning Tasks with a Haptic Interface

Haptic interface devices and teleoperation masters are multiple degree of freedom devices manipulated by an operator to generate real-time motion commands to simulated environments or robot manipulators. In this work we examine the relationship between the simulated friction parameters of a particular spatial positioning master device and the completion times of planar positioning tasks by human operators. It is expected that increasing the Coulomb or viscous friction of the device would tend to increase the completion times of less difficult, quicker positioning tasks and decrease completion times for more difficult fine positioning tasks requiring higher precision from the operator. A common haptic interface device was used to perform continuous sequences of planar positioning tasks. Each trial required 10-12 minutes to complete and consisted of 15 positioning sequences which varied in the size of the target regions and the magnitude and type of simulated friction in the device. With a sample size of 10 test subjects, small effects were generally observed as expected, with the exception of the first 3 to 4 sequences of the trials which are concluded to be an adaptation or learning period for the users during each trial

Surgical Robots at TIMC: Where We Are and Where We Go

Grenoble was one of the first places worldwide where a robot was used in clinical routine. In 1989, the first robot-assisted procedure on a patient took place in the neurosurgery department of the Grenoble University Hospital. An industrial robot modified to satisfy to the clinical constraints was used as a positioning device for guiding minimally invasively the surgical tool to a planned target. Based on that experience and on our knowledge of the clinical domain, we progressively re-directed our activity towards the design of specific robotic devices answering important issues among which safety, interactivity and clinical suitability. In this paper, we describe in more details our view of what surgical robotics is and should be and we illustrate our approach by the description and discussion of research in progress at TIMC: the PADyC arm, a passive device constraining the surgeon s motions in function of a pre-planned surgical protocol - the TER system a non rigid and portable robot for tele-echography - and LER a portable endoscope holder. We will discuss the specificities of medical robotics. Finally, we will draw the perspectives that we foresee for this domain.

Interactive robots for medical applications

Over the last two decades, medical robotics has evolved from the adaptation of industrial robots to medical tasks to a specific domain of robotics requiring the development of innovative architectures and control modes. In particular, robots enabling cooperation with the physician are being developed. We name them interactive robots. In this paper, we will present three examples of such robots: PADyC is a passive system which constrains the motions of the surgical tool held by the clinical operator in function of the surgical task; TER and PER which are two low weight, compliant robots respectively dedicated to tele-echography and endoscopy.

Robotic-surgical instrument wrist pose estimation

The Compact Lightweight Surgery Robot from the University of Hawaii includes two teleoperated instruments and one endoscope manipulator which act in accord to perform assisted interventional medicine. The relative positions and orientations of the robotic instruments and endoscope must be known to the teleoperation system so that the directions of the instrument motions can be controlled to correspond closely to the directions of the motions of the master manipulators, as seen by the the endoscope and displayed to the surgeon. If the manipulator bases are mounted in known locations and all manipulator joint variables are known, then the necessary coordinate transformations between the master and slave manipulators can be easily computed. The versatility and ease of use of the system can be increased, however, by allowing the endoscope or instrument manipulator bases to be moved to arbitrary positions and orientations without reinitializing each manipulator or remeasuring their relative positions. The aim of this work is to find the pose of the instrument end effectors using the video image from the endoscope camera. The P3P pose estimation algorithm is used with a Levenberg-Marquardt optimization to ensure convergence. The correct transformations between the master and slave coordinate frames can then be calculated and updated when the bases of the endoscope or instrument manipulators are moved to new, unknown, positions at any time before or during surgical procedures.