Towards High Fidelity Remote Palpation System

Remote palpation enables noninvasive tissue examination in telemedicine, yet current tactile displays often lack the fidelity to convey both large-scale forces and fine spatial details. This study introduces a hybrid fingertip display comprising a rigid platform and a 4x4 soft pneumatic tactile display (4.93 mm displacement and 1.175 N per single pneumatic chamber) to render a hard lump beneath soft tissue. This study compares three rendering strategies: a Platform-Only baseline that renders the total interaction force; a Hybrid A (Position + Force Feedback) strategy that adds a dynamic, real-time soft spatial cue; and a Hybrid B (Position + Preloaded Stiffness Feedback) strategy that provides a constant, pre-calculated soft spatial cue.

Psychophysical evaluations with 12 participants assessed lump detection and size discrimination using soft tissue phantoms. Detection accuracy increased from 50.0% (Platform-Only) to around 98% (Hybrid A and B), with elevated confidence and realism attributed to contact area modulation. Size discrimination accuracy reached 86.1% (Hybrid A) versus 63.9% (Platform-Only), underscoring the role of temporal-spatial cues in edge perception. Future efforts will enable real-time teleoperation, diverse tissue testing, and clinician validation.