Stable interaction with an n-DOF virtual object using a modified passivity based control architecture

In Networked haptic virtual environments, users can haptically interact with a shared virtual world from numerous workstations over an Ethernet local area network (LAN). Such networks suffer from the communication channels' difficulties such as delay, jitter and pocket loss. Such hindrances lead the closed-loop system to undesirable oscillations/instability. In this paper, by a utilized Passive Set-Position Modulation (PSPM) algorithm, passivity is enforced to a networked haptic virtual environment, involving a node-based n-DOF virtual object. In order to implement numerically, a novel approach is developed to transform the resulting optimization problem to a semidefinite optimization problem. The new method eliminates boundedness on interaction's stiffness and provides rendering interaction with either a rigid or deformable virtual object through dedicated networks or over the internet. The new modified PSPM framework was validated through some simulations.