Weston Blaine Griffin

Feedback strategies for telemanipulation with shared control of object handling forces

Shared control represents a middle ground between supervisory control and traditional bilateral control in which the remote system can exert control over some aspects of the task while the human operator maintains access to low-level forces and motions. In the case of dexterous telemanipulation, a natural approach is to share control of the object handling forces while giving the human operator direct access to remote tactile and force information at the slave fingertips. We describe a set of experiments designed to determine whether shared control can improve the ability of an operator to handle objects delicately and to determine what combinations of force, visual, and audio feedback provide the best level of performance and operator sense of presence. The results demonstrate the benefits of shared control and the need to carefully choose the types and methods of direct and indirect feedback.

Feedback strategies for shared control in dexterous telemanipulation

Shared control represents a middle ground between supervisory control and traditional bilateral control in which the remote system can exert control over some aspects of the task while the human operator maintains access to low-level forces and motions. Our telemanipulation system includes tactile, force and motion sensors that allow the slave to regulate grasp forces and impart rolling motions to a grasped object. We describe a set of experiments designed to determine whether shared control can improve the ability of an operator to handle objects delicately and to determine what combinations of force, visual and audio feedback provide the best level of performance and operator sense of presence. The results demonstrate the benefits of shared control and the need to choose carefully the types and methods of direct and indirect feedback.

A 10 Fr ultrasound catheter with integrated micromotor for 4D intracardiac echocardiography

We developed prototype catheters for real-time three-dimensional intracardiac echo (4D ICE) imaging. The catheter tips contained a low profile 64-element, 6.2 MHz phased array transducer and integrated micromotor, allowing oscillation of the transducer in the elevation direction. The tips were integrated with two-way deflectable 10 Fr catheters and used in in-vivo animal testing at multiple facilities. The 4D ICE catheters were capable of imaging a 90° azimuth by up to 180° elevation field of view. Volume rates ranged from 1 vol/sec (180° elevation) to approximately 10 vol/sec (45° elevation). We successfully imaged electrophysiology catheters, atrial septal puncture procedures, and detailed cardiac anatomy. The elevation oscillation enabled 3D visualization of devices and anatomy providing new clinical information and perspective not possible with current 2D imaging catheters.

An integrated vision-based robotic manipulation system for sorting surgical tools

In this paper, we introduced a robotic system using a humanoid robot, Baxter research robot, to pick-up surgical tools from a tray and place the tools into different trays according to the types of the surgical tools. The pick-n-place manipulation is integrated with a vision component and a special magnet gripper and governed by a finite state machine. This vision-based manipulation system allows the robot to check which tool is on top of the tools in a tray, to find the grasping points on the tools, to grab the tools using a magnet gripper, and to place them into different trays. Major technologies used in this system include: vision, magnet force control, force feedback, motion trajectory planning, and decision-making. We tested our system in a lab-based environment and the system performance satisfies the requirements of the project.

Robotic Handling of Surgical Instruments in a Cluttered Tray

We developed a unique robotic manipulation system that accurately singulates surgical instruments in a cluttered environment. A novel single-view computer vision algorithm identifies the next instrument to grip from a cluttered pile and a compliant electromagnetic gripper picks up the identified instrument. System is validated through extensive experiments. This research was motivated by the challenges of perioperative process in hospitals today. Current process of instrument counting, sorting, and sterilization is highly labor intensive. Improperly sterilized instruments have resulted in many cases of infections. To address these challenges, an integrated robotic system for sorting instruments in a cluttered tray is designed and implemented. A digital camera is used to capture an image of a cluttered tray. A novel single-view vision algorithm is used to detect the instruments and determine the top instrument. Position and orientation of the top instrument is transferred to a robot. A compliant electromagnetic gripper is developed to complete the gripping. Experiments have demonstrated high success rate of both instrument recognition and manipulation. In the future, error handling needs to be further reinforced under various exceptions for better robustness.

A vision-guided robot manipulator for surgical instrument singulation in a cluttered environment

The logistics of counting, sorting, sterilizing, and transporting surgical instruments is labor and capital intensive. Furthermore, infection due to improper sterilization is a critical safety hazard. To address these problems, we have developed a unique robotic manipulation system that is capable of accurately singulating surgical instruments in a cluttered environment. Our solution is comprised of two parts. First, we use a single-view vision algorithm for identifying surgical instruments from a pile and estimating their poses. Occlusion reasoning is performed to determine the next instrument to grip using a contrast invariant feature descriptor. Second, we design a compliant electromagnetic gripper that is capable of picking up the identified surgical instrument based on its estimated pose. We validate our solution through instrument singulation experiments demonstrating identification, localization accuracy, and robustness of occlusion reasoning as well as the flexibility of the electromagnetic gripper.

Navigation and imaging system sychronized with respiratory and/or cardiac activity

An imaging and navigation system is disclosed herein. The imaging and navigation system includes a computer and an ultrasonic imaging device disposed at least partially within an ultrasound catheter. The ultrasonic imaging device is connected to the computer and is adapted to obtain a generally real time three-dimensional image. The imaging and navigation system also includes a tracking system connected to the computer. The tracking system is adapted to estimate a position of a medical instrument. The imaging and navigation system also includes a display connected to the computer. The display is adapted to depict the generally real time three-dimensional image from the ultrasonic imaging device and to graphically convey the estimated position of the medical instrument.

An integrated robotic system for transporting surgical tools in hospitals

The performance of a hospitals sterile processing center (SPC) significantly impacts patient safety and overall productivity. Key to automating this process is to reliably transport instruments throughout the process. In this paper, we detail a robust integrated system for enabling mobile robots to autonomously perform manipulation of assets; specifically, transporting reusable surgical instrument trays in the SPC of a hospital. Our method is based on a cognitive decision making mechanism that plans and coordinates the motions of the robot base and the robot manipulator at specific processing locations. A vision-based manipulator control algorithm was developed for the robot to reliably locate and subsequently pick up surgical tool trays. Further, to compensate for perception and navigation errors, we developed a robust self-aligning end-effector that allows for improved error-tolerance in larger workspaces. We evaluated the developed integrated system using an Adept PowerBot mobile robot equipped with a 6-DOF Schunk PowerCube arm and our customized end-effector in an SPC-like environment. The experiment results validate the effectiveness and robustness of our system for handling surgical instrument trays in tight and constrained environments.

Method and apparatus for operating a micromotor in a fluid using a moisture barrier

A device and a method for sealing a micromotor with an optional associated gearbox are disclosed where, in one aspect of the present invention, a catheter tip comprises: a micromotor; an ultrasound imaging transducer; a gearbox mechanically coupled to the micromotor, the gearbox having a rotatable portion mechanically coupled to the ultrasound imaging transducer array; and a moisture barrier disposed so as to reduce or prevent acoustic coupling fluid from entering both the gearbox and the micromotor.