Evolving Grasping Structures

1. Evolving Grasping Structures SPL No. – D9 Supervisor – Prof. Sudipto Mukherjee Kalpesh Singal – 2004ME10658 Piyush Agarwal – 2004ME10508

2. Introduction • Human hand • One of the best evolved structure • Fantastic manipulability • Restricted joint degree of freedom • Thumb - A special finger Centuries of natural evolution to meet need of time • Attempt to imitate evolution in manipulating structure • Task based performance evaluation • Limited versatility • Not to exceed certain no. of finger and links

3. Objective • Desired Manipulations • Precision grasp objects- square, circular • Move and rotate object • Optimizing Grasping Structure • Reward: Precision, Versatility • Penalties: Cost of Information, Financial costs, Computational resources

4. Develop simulation to manipulate given for a fixed structure of hand Develop code to find M and C matrix given DH parameters Using Hertzian contact model Using Screw theory and imposing velocity constraints at point of contact Manipulate object given DH parameters of hand Optimize DH parameters to find best solution Approach

5. Hertzian Contact Model • Hand has two fingers with two degree of freedom each • Object-finger interaction modeled using Hertzian contact model - sphere in contact with the flat plate

6. Drawbacks of Hertzian Model • Computationally inefficient for cases when contact forces not normal • Difficult to automate the process of writing the equation of motion • Difficult to compute the inverse kinematics relations automatically

7. Two fingered hand with the fingers having three degrees of freedom each Dynamics of System is given by: where, Screw Theory Approach

9. Automation • Find M and C matrices from DH parameters

10. GanttChart

11. Thank You