1 Haptic Systems Mohsen Mahvash Lecture 3 11/1/06

2  A review of the last lecture  The definition of haptic rendering  Haptic simulation of a spring  Haptic simulation of the gravitational forces between two objects  Examples of force functions  Haptic rendering of contact  Physically based haptic rendering and the challenges  References Introduction to Haptic Rendering

3 A Review of the Last Lecture Tip SensAble Phantom Omni

4 “Haptic rendering is the process of computing and generating forces in response to user interaction with virtual environment” Computing forces and torques that should be applied to the tip of the haptic display in order to represent forces of a physical phenomena or represent some data Tip The definition of haptic rendering

5 Haptic Simulation of a Spring Algorithm for simulation of spring //Virtual spring

6 Haptic simulation of the gravitational forces between objects For

7 Haptic simulation of the Solar System Calculate gravitational forces for every sphere and then add

8 Examples of force functions A function of time A function of tip position or tip displacement of time A function of tip Velocity A general function You may not be able to implement some general functions (Because of high order derivatives)

9 Haptic simulation of contact god object proxy contact point

10 Haptic simulation of contact :unit vector normal to surface :unit vector tangent to surface

11 Haptic simulation of contact Haptic Scene Rigid or Deformable Graphic Scene Deformable object Graphic Scene Rigid object

12 Rigid and Deformable Objects Deformable bodies: Location, geometry, frictional properties, material, support, internal structure Rigid bodies: Location, geometry and frictional properties Elastic material Viscoelastic material Plastic material

13 Haptic Rendering of Deformable Objects

14 Physically Based Haptic Rendering and the Challenges Rendering forces should depend on material properties It is very time-consuming to calculate rendering forces from material properties using conventional engineering approaches such as Finite Element Methods

15 Tomorrow Real-time programming for haptics References 1.Salisbury, K., Brock, D., Massie T., Swarup, N., Zilles, C Haptic Rendering: Program-ming Touch Interaction with Virtual Objects. Proc. Symposium on Interactive 3D Graphics, ACM. pp D Touch™ SDK OPENHaptics™TOOLKIT, Programming Guide, 3.Mahvash, M., Hayward, V High Fidelity Haptic Synthesis of Contact With Deformable Bodies. IEEE Computer Graphics and Applications. 24(2): 48-55, 2004