A Robot for Automated Motion A Robot for Automated Motion Scaling in Robotic MicrosurgeryScaling in Robotic Microsurgery

Group 2

Keshav Chintamani

Lavie Golenberg

Prashanth Mathihalli

Problem Statement

• Different surgical tasks require varying motion scales (MS) between the surgeon and the end-effector

– E.g. Suturing vs. gross translation have different scale requirements

• Surgeons currently keep the MS constant due to– Inconvenience and interruptions during procedures– Higher mental workload– Failures in selecting correct scales might lead to fatal

errors – May require an additional technician

Currently…Currently…

• A touch screen allows the surgeon or technician to change the motion scale value

• The scale is a semi circle with a minimum value of 1 and a maximum of 10

• Tapping the circumference changes the MS value of the Zeus robot

Specific AimsSpecific Aims

• Design and construct an Automated Motion Scaling Robot (AMSR)

– Hardware– Software

• Integrate the AMSR with zeus robot system• Analysis and validation of the AMSR through an

objective human factors study

The HypothesesThe Hypotheses

• Eliminate the need for a technician

• Remove pauses during operations

• Be capable of changing the MS more frequently

• Deliver MS changes more accurately than a human

• Not be susceptible to fatigue• Create a more responsive

system

The AMSR will:

HardwareHardware

Design RequirementsDesign Requirements

• A two degree-of-freedom (DOF) RP robot arm– One rotational and one prismatic joint– Damping mechanism to prevent damage to the touch

screen– Rapid input/output response– Provide accurate responses to inputs from the surgeon– Provide ease of removal during maintenance and repair

Design Requirements, Contd..Design Requirements, Contd..

• Designing the Robot Mount to provide– A high center-center accuracy between

the AMSR and the Motion Scale– Variable chassis geometry settings for the

AMSR for calibration

Design HurdlesDesign Hurdles

• Providing motors with sufficient torque

• Providing a unique design that is – Replaceable– Reliable– Sensitive to pressure

Preliminary Concepts for the Prismatic Joint

Preliminary Concepts for the Prismatic Joint

Motor SelectionMotor Selection

• A high torque motor was chosen for the base (rotation)

– 300 deg/sec Angular Velocity– 11 Kg/cm Peak Torque

• A light weight motor for tapping (translational)

– 24 g net weight– 3 Kg/cm Peak Torque– 350 deg/sec angular velocity

SoftwareSoftware

ElectronicsElectronics

• Robix RCS-6 Controller• Controller provides support for

– 6 servos with 6 sensor inputs– Parallel port data transmission

• The programming was done in Microsoft Visual C++ 6.0

Robot Control SoftwareRobot Control Software

• Fully integrated control functions for– Speed, acceleration and deceleration of

servos– Positional feedback– Additional sensor data acquisition

capabilities

Final DesignFinal Design

Final Design: 2D Views Final Design: 2D Views

Final Design: 3D ViewFinal Design: 3D View

A Descriptive VideoA Descriptive Video

The AMSR!The AMSR!

EvaluationEvaluation

MethodologyMethodology

• Obtain preliminary data for 3 humans and the AMS Robot performing a tapping task

• Compare performance between the robot and the subjects

Preliminary Human Factors TestPreliminary Human Factors Test

• Participants were provided with 5 minutes for practice on the MS display

• They were asked to input 99 values based on verbal prompts from the experimenter

• Participants were asked to tap values with and without a stylus

• Values displayed on screen were recorded

AnalysisAnalysis

• A within-subjects factorial design was used

• The experiment was balanced using a Latin square

• The data was analyzed for input error

Results, Discussion Results, Discussion & Conclusion& Conclusion

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Error variation between factors

Error variation between AMSR and Human

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ConclusionConclusion

• Human beings are incapable of the level of dexterity that robots possess

• Hand movements with a stylus improved human performance

• The AMSR can provide more rapid and accurate cyclic responses than a human

• These responses are repeatable

Conclusion, contd…Conclusion, contd…

• With the AMSR, surgeon performance can immensely be enhanced

• Surgeon fatigue and workload can be reduced

• Can result in efficient surgeries with reduced time durations

Future WorkFuture Work

Future WorkFuture Work

• Creating a closed loop system• Increase the accuracy of the robot• Continue subject testing• Analyze performance of linear scales over

semi-circular scales• Provide various forms of input methods

Future Work, contd…Future Work, contd…

• Combine AMSR with Automatic Motion Scaling

• This study can lead to further research into human hand tracking performance

• Develop display methods/cues for enhancing performance

Thank youThank you

ReferencesReferences

• S. M. P. M. Sunil M. Prasad MD*, Hersh S. Maniar MD†, Celeste Chu MD*, Richard B. Schuessler PhD* and Ralph J. Damiano, Jr. MD*, Corresponding Author Contact Information, FACS, "Surgical robotics: Impact of motion scaling on task performance," 2004.

• R. D. Ellis, A. Cao, A. Pandya, A. Composto, M. D. Klein, and G. Auner, "Minimizing Movement Time In Surgical Telerobotic Tasks," presented at 49th Annual meeting of the Human Factors and Ergonomics Society Orlando, Florida, 2005.

• J. Accot and S. Zhai, "Scale effects in steering law tasks," CHI, vol. No.3, pp. 1-8, 2001.

• P. M. Fitts, "The Information Capacity of the Human Motor System in Controlling the Amplitude of Movement," Journal of Experimental Psychology, vol. Vol. 121, pp. 262-269, 1954.

• S. M. P. M. Sunil M. Prasad MD*, Hersh S. Maniar MD†, Celeste Chu MD*, Richard B. Schuessler PhD* and Ralph J. Damiano, Jr. MD*, Corresponding Author Contact Information, FACS, "Surgical robotics: Impact of motion scaling on task performance," 2004.

• R. D. Ellis, A. Cao, A. Pandya, A. Composto, M. D. Klein, and G. Auner, "Minimizing Movement Time In Surgical Telerobotic Tasks," presented at 49th Annual meeting of the Human Factors and Ergonomics Society Orlando, Florida, 2005.

• J. Accot and S. Zhai, "Scale effects in steering law tasks," CHI, vol. No.3, pp. 1-8, 2001.

• P. M. Fitts, "The Information Capacity of the Human Motor System in Controlling the Amplitude of Movement," Journal of Experimental Psychology, vol. Vol. 121, pp. 262-269, 1954.