Bionics Lab › Research > Surgical Robotics > Surgery Project 9

Trauma Pod - Phase 1
The Operating Room of the Future


Background The Trauma Pod (TP) vision is to develop a rapidly deployable robotic system to perform critical acute stabilization and/or surgical procedures, autonomously or in a teleoperative mode, on wounded soldiers in the battlefield who might otherwise die before treatment in a combat hospital could be provided.

Methods In the first phase of a project pursuing this vision, a robotic TP system was developed and its capability demonstrated by performing selected surgical procedures on a patient phantom.

Results The system demonstrates the feasibility of performing acute stabilization procedures with the patient being the only human in the surgical cell. The teleoperated surgical robot is supported by autonomous robotic arms and subsystems that carry out scrub-nurse and circulating-nurse functions. Tool change and supply delivery are performed automatically and at least as fast as performed manually by nurses. Tracking and counting of the supplies is performed automatically. The TP system also includes a tomographic X-ray facility for patient diagnosis and two-dimensional (2D) fluoroscopic data to support interventions. The vast amount of clinical protocols generated in the TP system are recorded automatically.

Conclusions Automation and teleoperation capabilities form the basis for a more comprehensive acute diagnostic and management platform that will provide life-saving care in environments where surgical personnel are not present.



Trauma Pod conceptual video clip (credit - Dr. Richard Satava)


“Vision without execution is hallucination.” (Thomas Edison)

Trauma Pod Phase 1- Panoramic Overview (Photo Credit - SRI)

Trauma Pod Phase 1 - Final Demo (Video Credit - SRI)

Tool Rack Subsystem (TRS)
Automatic Surgical Robotics Tool Changer


The TRS is a fully automated tool changer, whose overall dimensions are 0.18 X 0.68 X 1.5 m, that is capable of holding, accepting, dispensing, and maintaining the sterility of 14 surgical tools for the da Vinci robot.

TRS Hardware

The TRS (Fig 10a) contains a round magazine, of 0.45 m diameter and 0.687 kg·m2 inertia, with 15 tool positions. The magazine is located in the TRS stationary base. One tool position is occupied by a compliant calibration lug used to locate the TRS with respect to all the other TP subsystems. The magazine can be removed from the TRS along with the surgical tools it contains for sterilization. All sensors and actuators are located below a sterility barrier and do not touch the tools. Each tool is held by a tool-holder mechanism that includes a vertical push rod to which two conical cams are attached. When the push rod is actuated, each cam opens two normally-closed, spring-loaded jaws that grasp the shaft of a tool with a tensional stiffness of 0.8 Nm. The tool-holder compliance copes with potential angular misalignment (up to 5 degrees) of the tool as it is retrieved from or presented to the TRS by the stiff SNS. Two geared, brushless servo motors (made by Animatics, Inc.) actuate the TRS push rod in less than 100 ms.

Figure: Tool rack subsystem. (Top) overview; (bottom) tool holder grasping a surgical tool, and CAD display of tool holder grasping a surgical tool under permissible angular misalignment.

TRS Software

The TRS is controlled by high-level and low-level control software. The high-level control software is based on a spread protocol [10] and communicates with the TP system using an XML schema. In addition to providing generic messages regarding its status, alarm, and inventory report, the TRS supports other types of message, such as locating and presenting a requested tool, closing or opening a gripper, and reading a tool RFID.

The TRS low-level control software sends commands over a single RS-232 serial port to the two servo motors that actuate the TRS push rod. The RS-232 line is arranged in a loop so that each actuator echoes packets down the chain and eventually back to the PC.

TRS Function and Performance

The TRS must be able to (1) dispense and accept a tool that is presented to the TRS within a specified maximum pose misalignment by the stiff SNS, and to absorb the energy resulting from such misalignment, and (2) move and present the desired tool in a given pose and within a given time. It was found experimentally that the TRS has the following misalignment tolerances: 4 mm positional, 2.8 degree orientation, 5.7 to 7.8 N/mm linear stiffness, and 0.8 N·m tensional stiffness. These tolerances exceed the worst-case misalignment between the TRS and the SNS by a factor of 2; hence, there can be no damage to the SNS or the TRS as a result of such misalignment. We also found experimentally that the time required for presenting a tool to the SNS (which may be done clockwise or counterclockwise) varies between 0 to 648 ± 8 ms (see Fig. 11), and that the time required for tool release or grasping is 98 ± 8 ms. These results meet our analytical finding that the TRS must present the requested tool to the SNS in less than 700 ms in order for that tool to reach the SRS in less than 10 s.

Figure: Clockwise and counterclockwise tool-presentation time vs. initial tool position.

System Overview

All Functions: Calibrations, Tool Loading, Tool Releasing

Requirement - The TRS shall receive / release and lock / unlock in SRS tools in 0.1 seconds (goal) with a maximum of 0.3 seconds within receipt of command.

Performance - Release Tool – 0.088 s Receive Tool – 0.076 s

Magazine Change

Goal: The TRS shall be capable of sustaining autoclave-based cleaning and sterilization with tools installed

Reading RFID tags from each tool

Requirement - The TRS shall be able to sense how many SRS tools there are, location of specific tools and whether they have been used.

Robust surgical tool loading (misalignments)

Requirement - The TRS shall be able to present any SRS tool in its rack for acquisition by the SNS with a position accuracy and repeatability of +/-0.65mm and orientation accuracy and repeatability of +/-0.2deg.

Performance - Repeatability of +/-0.177 deg

Manual surgical tool loading

Surgical tool holding mechanism

Requirement - The TRS shall incorporate passive compliance to accommodate a misalignment with the SNS end-effector of +/-4mm in any direction axes and +/- 2.8 degrees in any rotational axes, while inserting a tool or picking it from the TRS.

Requirement - The TRS shall have removal forces (what the SNS/EE must overcome for tool placement or removal) of less than 1lb

Performance – Releasing Force Pinchers Open – 0 N Pinchers Close - 12 N Overcoming the active passive grasping


This project was made possible with the financial support and technical guidance provided by the Defense Advanced Research Program Agency (DARPA) and Telemedicine Advanced
Technology Research Center (TATRC) staff. The contributions of the following organizations is acknowledge: SRI International, University of Washington, University of Texas, Oak Ridge National Laboratory, General Dynamics Robotic Systems, Robotic Surgical Technologies, University of Maryland, Integrated Medical Systems, Intuitive Surgical Inc., Multi Dimensional Imaging, University of Cincinnati, Stanford University.


Automatic Tool Changer

| Status: Completed |


(*) Note: Most of the Bionics Lab publications are available on-line in a PDF format. You may used the publication's reference number as a link to the individual manuscript.

[ JP20] Pablo Garcia, Jacob Rosen, Chetan Kapoor, Mark Noakes, Greg Elbert, Michael Treat, Tim Ganous, Matt Hanson, Joe Manak, Chris Hasser, David Rohler, Richard Satava, Trauma Pod: a semi-automated telerobotic surgical system, The International Journal of Medical Robotics and Computer Assisted Surgery, Vol. 5, No. 2, pp. 136-146, June, 2009

[ CP30] Friedman Diana, Jesse Dosher, Timothy M. Kowalewski, Jacob Rosen, Blake Hannaford, Automated Tool Handling for the Trauma pod Surgical Robot, International Conference of Robotics and Automation (ICRA 07), Rome, Italy