slide1 n.
Download
Skip this Video
Loading SlideShow in 5 Seconds..
Robots In Spine Biomechanics PowerPoint Presentation
Download Presentation
Robots In Spine Biomechanics

Loading in 2 Seconds...

play fullscreen
1 / 20

Robots In Spine Biomechanics - PowerPoint PPT Presentation


  • 223 Views
  • Uploaded on

Robots In Spine Biomechanics. Wafa Tawackoli, Michael A.K. Liebschner Department of Bioengineering Rice University. Motivation. In vitro study of human spine for various complex physiological loading. Prediction of stress fracture risk. Everyday activities

loader
I am the owner, or an agent authorized to act on behalf of the owner, of the copyrighted work described.
capcha
Download Presentation

PowerPoint Slideshow about 'Robots In Spine Biomechanics' - sharne


An Image/Link below is provided (as is) to download presentation

Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author.While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server.


- - - - - - - - - - - - - - - - - - - - - - - - - - E N D - - - - - - - - - - - - - - - - - - - - - - - - - -
Presentation Transcript
slide1

Robots In Spine Biomechanics

Wafa Tawackoli, Michael A.K. Liebschner

Department of Bioengineering

Rice University

motivation
Motivation
  • In vitro study of human spine for various complex physiological loading.
  • Prediction of stress fracture risk
  • Everyday activities
    • Trauma (i.e. Car accident, Sports)
    • Occupational ($54 billion/year)
      • Relatively low impact office duties
      • High impact manual labor
  • Osteoporosis (~$13 billion/year)
  • Approximately 700,000 vertebral fractures occur each year in USA
anatomy
Anatomy

Annulus fibrosus

Posterior Elements

Nucleus pulposus,

Facet Joint

COR

Cortical Shell (rim)

Trabecular bone

Vertebra

IntervertebralDisc

Cramer, 1995

primary goals
To understand the biomechanical behavior of spinal segments under complex physiological loadingPrimary Goals
  • 3D motion path
  • Simulation of in vivo complex loading
  • Investigate stress fracture risk base on physiological loading
a 3d coordinate system
A 3D coordinate system

+ Z Rotation

  • Total of 6 load components may be applied
    • Three forces
    • Three moments
  • Each load component may produce 6 displacement components
    • Three translations
    • Three rotations
  • 36 load displacement curves can be generated

+ X Direction

+ Z Direction

+ X Rotation

+ Y Rotation

+ Y Direction

complications
Mechanical Properties are difficult to ascertain.

Spine movies in a complex 3-Dimensional pattern.

However, it is important to apply such complex motion during in vitro studies.

Complications
biomechanical methods
In vivo experiments (including imaging studies, i.e. stereoradiography) (Tibrewan, Pearcy)

Mechanical Testing (Panjabi, Hansson, Adams)

Computational Modeling (finite element analysis) (Uppala, Williams)

Biomechanical Methods
biomechanical methods cont d
Mechanical Testing Devices

Pulley system (Crawford, Panjabi, Patwardhan)

Uniaxial system (Adams, Panjabi, Brickmann) (Servo-Hydraulic or Pneumatic)

Mechanical Testing Methods

Uniaxial compression/tension

Shear

Bending (Flexion, Extension, Lateral, Torsion)

Compressive axial preload (Follower Load)

Biomechanical Methods (cont’d)
biomechanical methods cont d1
Biomechanical Methods (cont’d)
  • Spine Testing Machine:
  • Pulley system
  • Linear servo actuator (Parker-EBT 50)
  • 6 DOF Transducer (ATI-Omega 160)
  • Bi-axial tilt sensor (range of ~60o)
  • Optical tracking system
  • Compressive axial preload capability (up to 2250 N)
biomechanical methods cont d2

Top View

Side View

Cable

guide

U-Shape Bracket

Biomechanical Methods (cont’d)

Flexion

Force

Extension

Force

Sagittal View

ATI-160

Dead Weights

limitations
Measurement of spinal rigidity in single plane is very complex

Unconstrained Motion- 6 Degrees of Freedom (DOF)

2 DOF applied force + moment

Lack of knowledge of disc degeneration (tears or lesions)

Limitations
our approach
Measurement of spinal rigidity under complex loading (Fatigue, Creep, Stress Relaxation)

Decrease DOF of unconstrained motion

Increase DOF of applied forces and moments

Apply helical axis of motion (path of minimum resistance)

Load and displacement boundary conditions.

Our Approach
concept of kuka robotic arm

Wrist

Arm

Link arm

Rotating column

Base frame

Concept of KUKA Robotic Arm
  • 6 Degree of Freedom
  • PC computer
  • Windows based program (GUI software)
  • Manual and automatic control
  • Simple modular system
coordinate systems
Coordinate Systems
  • Coordinate systems (can be defined by the operator):
  • Sensor & Tool coordinate systems
  • Base coordinate system
  • Virtual coordinate system
sensing and control process 1
Sensing and Control Process (1)

Displacement

EZ

NZ

Load

Hybrid Control = { load control & displacement control }

sensing and control process 2
Sensing and Control Process (2)

Forces and torques measured by the ATI transducer can be re-calculated to a virtual coordinate system in order to sense the real effecting forces and torques between spinal segment and the transducer.

The optical tracking system allows for comparison in movement between each vertebra.

motion envelope
Motion Envelope

Ω

Reference (Home) Position

φ

Foundation Points

(Manually determined)

Top View of Motion Envelope

Boundary condition (i.e. Bending moment of 5 N.m.)

conclusion
Human spine is a complex system therefore complex motion behavior is expected

Hybrid control for biomechanical testing is recommended

6DOF robotic testing system can be applied to the delineation of in vitro spine kinetics

Conclusion
acknowledgment
Computational and Experimental Biomechanics Lab

KUKA USA Robotics

KUKA Development Labs

ATI Industrial Automation

Joe Gesenhues(Ryon Engineering Lab, Rice University)

Acknowledgment
thank you
Thank You

Robots in Biomechanics

Research