Real-time softness display system for the perception of virtual objects

Haptic perception and display of softness are important parts of the haptic display technique, which is currently the frontier in teleoperation systems and human-computer interaction. A portable softness display device is developed for this study. The device can quickly change the displayed stiffness by controlling the deformable length of the elastic element. Ideally, when a human operator´s fingertip presses the device, one will feel as if he/she actually pressed a soft object. A virtual softness display system based on the softness display device is also developed, which mainly includes geometric modeling of virtual objects, collision detection, and deformation modeling. The system can provide visual and haptic feedback, synchronously allowing operators to manipulate objects in the virtual environment. The Gauss deformation model is proposed to simulate the deformation of virtual objects. Based on the feature of haptic interaction, an extensible software architecture based on the Model-View-Controller pattern and plugin is given. Based on the simulation results, the softness display system is found to be efficient and credible.