Claudio Pacchierotti

The perceived realism of virtual body illusions, such as arm elongation, is dependent on congruent sensory feedback. This paper explores the effects of visio-haptic stimulation on the sense of embodiment in Virtual Reality (VR). We conducted three experiments. The first identified the optimal parameters for vibrotactile feedback by varying stimulation location and motor activation duration (250, 500, 750 ms) during a fixed visual task of 40% arm elongation over 18 seconds. We found that sequential stimulations along the entire arm with a 500ms duration per motor were the most effective. From this, we derived a formula to generalize the optimal haptic timing based on elongation velocity. The formula was then validated in two follow-up experiments: one varying the elongation percentage (26% to 80%) and another varying the elongation duration (9s to 27s). Our findings offer validated guidelines for designing more immersive haptic experiences for virtual body deformations.

Safe and intuitive telemanipulation of multiple microrobots is limited by visual occlusions that compromise control and task success. This paper introduces a shared control framework that guarantees safety and visibility by formulating the control problem as a constrained optimization problem. Our framework combines Control Lyapunov Functions (CLFs) for operator-driven stability with High-Order Control Barrier Functions (HOCBFs) to enforce collision and occlusion avoidance, all resolved within a real-time Quadratic Program (QP). A key innovation is a rendering technique based on the QP’s Lagrange multipliers, which are used to decompose the optimal control solution. This method isolates the effects of individual constraints to provide the human operator with distinct, interpretable visuohaptic cues for navigation and avoidance. The architecture also includes a viewpoint optimization system with a virtual autonomous camera to maximize task visibility. The framework is validated via two user studies in simulation and a demonstration on a real-world electromagnetic microrobotics actuation system. Results confirm that our visuo-haptic shared control strategies significantly improve user performance and task completion rates, while the control design provably prevents the microrobots from colliding or entering occluded regions.