Haptics of Pulse Palpation: Simulation and Validation through Novel Sensor-Actuator System

Palpation of arteries holds significant physiological importance. Existing pulse actuator designs intended to replicate the haptic sensations of palpation primarily focus on normal force interactions, often overlooking the shear forces generated by oscillations of the arterial wall during blood flow. This study aims to evaluate the normal, longitudinal, and transverse forces exerted by arteries through both theoretical and experimental analyses during palpation. The experimental validation features a pulse actuator-sensor system. The actuator component is a hydroelectromagnetic actuator, while the haptic sensing is performed by the Subblescope. The Subblescope measures arterial force feedback from both soft and hard artery models, as well as from the radial pulse in 18 human subjects. Mathematical analysis establishes the operational range of the sensor-actuator system as 0.005 N to 2.5 N. The force feedback from the simulation has been used for designing the total force generation by the actuator. The reactive force along the Z-axis varies between 19.3 mN to 500 mN, while the transverse and longitudinal forces along the Y and X axes range from 6.9 mN to 88.01 mN and 5.46 mN to 87.85 mN, respectively. The pulse-force map of the hard artery reveals higher three-dimensional force interactions compared to the soft artery. The hydroelectromagnetic actuator effectively generates both normal and shear forces during pulsatile flow. Future work will focus on developing training modules that replicate pulse haptics associated with various physiological conditions, such as diabetes.