Using analytical force model for efficient deformation simulation and haptic rendering of soft objects

High refresh rate required for haptic rendering has been an issue in immersive virtual-reality based simulation. It prohibits the use of physically accurate yet computationally intensive force models. In the paper, we propose to adopt analytical force model to render feedback forces during interactive simulation of soft-object deformation, which allows force computation to be executed directly in the 1 kHz haptic servo loop. The force model is explicitly expressed by the size and shape of tool-tip and the physical properties of materials. On the other hand, graphics rendering of the resulted deformation is achieved with efficient geometric modeling, where the size of the deformed region is calibrated with simulated deformation calculated using the finite element method (FEM) to guarantee physical accuracy. Experimental results demonstrate that the forces rendered by the analytical force model are comparable to that of FEM simulation. The proposed approach has the potential to be an alternative approach to interactive deformation simulation of soft objects in virtual reality applications.