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 The Vertebrate Analyzer*

The goal of our research is to create an accurate virtual model of an extinct animal, the Saber Tooth Cat or Smilodon. The Smilodon was the largest of the Saber Tooth Cats and went extinct about 11,000 years ago. It stood approximately 4' 5" and could grow to weigh in excess of 400 lbs. This is smaller yet heavier that modern day lions. The Smilodon's most defining features are it two huge canines, these teeth were serrated with an oval cross-section and could grow to be 7" long. Another interesting fact about the Smilodon is that it could open its jaw up to 120°, lions can't open past 65°. This combination of very long teeth and large jaw angle, coupled with its size and strength made the Smilodon a great hunter. For more background infomation on the Smilodon check out Enchanted Learning.

 

*This project is funded by the University at Buffalo Interdisciplinary Research & Creative Activities Fund.

   
 Students Involved:

- Leng-Feng Lee, PhD Candidate, University at Buffalo.

- Kannan Srikanth, M.S. Candidate, University at Buffalo.

- Madusudanan Narayanan, M.S. Candidate, University at Buffalo.

- Anand Naik, M.S. Candidate, University at Buffalo.

- Michael Del Signore, M.S., University at Buffalo [Graduated]

- Kiran S Konakanchi, M.S., University at Buffalo [Graduated]

- Talib S. Bhabrawala, M.S., University at Buffalo [Graduated]

 
 
 Research Issue :

1. Bite Force Estimation in members of the feline family (living and extinct);

2. Specific Case Study/ Musculoskeletal Model: Sabertooth Cat (Smilodon);

3. Examine various aspects of systematic musculoskeletal model building with the help of detailed examples;

4. Explore various issues pertaining to the modeling and analysis of such systems and provide possible solutions. 

 

 Research Progress - CAD / Mathematical Modeling :

Preliminary Simulations Using Existing Engineering tools:

- Virtual Recreation of Discovery Channel Model (Solid Works);

- Prescribed Motion Analysis (Visual Nastran 4D);

- Generation of CAD Model from CT scans of Sabertooth Skull;

- Creation of dynamic simulation using VN4D.

Discovery Channel Model and Prescribed Motion Visual Nastran Simulation

 

Muscles modeled using linear actuators:

Simulation was met with difficulty due to the program's inability to resolve actuator redundancy (more actuators than degrees of freedom).

 

 

Mathematical Model and MATLAB GUI Implementation:

- As a result of the difficulties encountered when using existing computational tools a mathematical model and virtual simulation were developed.

- Screw-theoretic model methods typically seen in the context of parallel robots were used to develop a 2-D mathematical model of the skull/mandible structure of the Cat.

- Each muscle is modeled as an RPR (Revolute-Prismatic-Revolute) manipulator.

- A typical pseudo-inverse solution is used to resolve actuator redundancy

- To ensure that each muscle force is positive and minimized an optimization routine was implemented.

- The mathematical model was then implemented into a MATLAB GUI, which serves as a low-resolution computational model.

- The GUI solves for minimum positive muscle forces given a desired external (bite) force, and muscle locations. (Inverse Dynamics Model)

 

Simulation Settings

Simulation Results

 On-Going Efforts:

- Implementation of muscle properties (i.e. passive stiffness) into current mathematical model.

- Creation of forward dynamics model (Given Muscle forces solve for bite force) based on a modified hill model and muscle properties. This will allow for an iterative study comparing muscle and bite forces.

- Finalize design, generate mechanical drawings, and begin manufacturing of mechanical apparatus.

GUI developed to assist mechanism load analysis

 Research Progress - Musculoskeletal Modeling :

Perform musculoskeletal analysis using the AnyBody package:

 

 

 

Mathematical Model and MATLAB GUI Implementation:

Results:

Note: More results can be found in the presentation [PPS].

 

On-Going Effort:

- Implementation of muscle properties (i.e. passive stiffness) into current mathematical model.

- Implement optimization routine instead of parametric sweep to determine the muscle location.

 

   
 Research Progress - Design and Development of  Mechanical Prototype for Hardware-in-the-Loop (HIL) Testing :

- Design of mechanical apparatus that will mount dentitions created from CT scans of feline skulls.

- Full adjustability to allow for proper rotation and orientation of skull and mandible with respect to each other.

- Load analysis performed for application desired bite force, and selection of proper motors/ actuators.

Previous Mechanism Design

Current Mechanism Design

   
 Related Publications - Conference Proceedings:
[03] M. J. Del Signore, R. Bhatt, and V. Krovi, "A Screw-Theoretic Analysis Framework for Musculoskeletal Systems", accepted for the Proceedings of 2006 ASME International Design Engineering Technical Conferences, Philadelphia, Pennsylvania, USA, Sep 10-13, 2006. [PDF]
[02] T. S. Bhabrawala, and V. Krovi, “Shape Recovery from Medical Data Using Extended Superquadrics,” Proceedings of the 2005 ASME Design Engineering Technical Conferences, DETC2005-84738, Long Beach, California USA, September 24-28, 2005. [PDF]
[01] M. Del Signore, V. Krovi, and F. Mendel, "Virtual Prototyping and Hardware-in-the-Loop Testing for Musculoskeletal System Analysis", 2005 IEEE International Conference on Mechatronics and Automation, Niagara Falls, Ontario, Jul 2005. [PDF]
     
 Related Publications - Theses & Projects:
[03] Del Signore, M. J., A Screw-Theoretic Framework for Musculoskeletal System Modeling and Analysis, M.S. Thesis, Dept. of Mechanical & Aerospace Engineering, SUNY at Buffalo, Feb. 2006. [PDF] [PPS]
[02] K. S. Konakanchi, "Musculoskeletal Modeling of Smilodon Fatalis for Virtual Functional Performance Testing", M.S. Project, Mechanical & Aerospace Engineering Dept., University at Buffalo, Sep 2005. [PDF] [PPS]
[01] Bhabhrawala, T. S., Shape Recovery from Medical Image Data using Extended Superquadrics, M.S. Thesis, Dept. of Mechanical & Aerospace Engineering, SUNY at Buffalo, Feb. 2005. [PDF] [PPS]
     
 Related Publications - Poster Presentations:
[02] M. Del Signore, "Robotics and Virtual Prototyping Applied to Musculoskeletal System Analysis", Sigma Xi Graduate Research Poster Presentation,  Apr 2005. [PDF]
[01] K. S. Konakanchi, "Musculoskeletal Modeling Using Virtual Prototyping Tools", Sigma Xi Graduate Research Poster Presentation, Apr 2005 [PDF]
     
 

 

Last update: 10/27/2008