A Contact Point Intermediate Representation for 6-DOF Haptic Interaction With Dynamic Simulations

Abstract

Abstract A new method for integrating a haptic interface device with 3-D dynamic simulations has been implemented which minimizes effects caused by the limited update rate of the simulation and unpredictable communication delays. The new contact point intermediate representation method is compared with a previously implemented method of virtual coupling. Both methods were applied to a recently developed 6 DOF haptic interface device based on Lorentz magnetic levitation connected with a real-time dynamic physical simulation environment. With virtual coupling, the position and orientation data from the interface device and the simulated tool each act as impedance control setpoints for the other, with error and velocity feedback acting as virtual coupling between the two systems. The simple feedback coupling enables the overall stiffness and stability of the system to be tuned easily. In the contact point intermediate representation integration method, the haptic device controller uses additional contact point position and direction information from the simulation to react to user motions by changing the device impedance appropriately at the faster update rate of the controller rather than at the slower simulation rate. The contact point intermediate representation provides a crisper, more responsive feeling than virtual coupling during interaction but is not as easily stabilized. Experimental data from the virtual coupling and a modified contact point intermediate representation implementation are presented.