Multi-fingered haptic palpation using pneumatic feedback actuators

• Our pneumatic feedback actuators provide haptic sensations at multiple fingers.
• The actuators vary the stress on the fingertips in accordance with tissue stiffness.
• The proposed method reduces actuator elements compared to tactile actuators.
• The proposed method provides more information than single-point force feedback.
• Finite element modeling and user study confirm the efficiency of our method.

This paper proposes a multi-fingered palpation method which employs pneumatic haptic feedback actuators allowing users to experience haptic sensations at multiple fingers while carrying out remote soft tissue palpation. Pneumatic actuators are used to vary the stress on the user's fingertips in accordance with the tissue stiffness, experienced during manual palpation. The proposed method reduces actuator elements compared to tactile actuators and provides more information than single-point force feedback. The results of our finite element analysis have proven that our pneumatic haptic feedback device can recreate the contact stress between fingertip and soft tissue during palpation. The accuracy (96.8% vs. 93.3%) and time-efficiency (4.6 s vs. 8.3 s) advantages of using three-fingered over single-fingered palpation have been confirmed in our user study results of stiffness levels discrimination. Relatively good tumor detection sensitivities have been demonstrated by the palpation user study which has showed a direct correlation between tumor size and detection sensitivity and has further proven the efficiency of the proposed actuator and multi-fingered palpation method for tumor detection in palpation simulation.