Haptics of Pulse Palpation: Simulation and Validation through Novel Sensor-Actuator System
Debadutta Subudhi, Manivanna M, K K Deepak
AI summary
Problem
Current pulse palpation simulators predominantly deliver unidirectional normal force feedback, neglecting the critical longitudinal and transverse shear forces generated by arterial wall oscillations during blood flow.
Approach
The researchers designed a hydro-electromagnetic actuator and multi-axis force sensor to measure and generate 3D pulse forces, validating the system through fluid-structure simulations, synthetic artery phantoms, and human radial pulse trials.
Key results
- Operational force range established between 0.005 N and 2.5 N
- Z-axis reactive forces measured from 19.3 mN to 500 mN, with transverse and longitudinal forces ranging from ~5.5 mN to ~88 mN
- Hard artery models demonstrate significantly higher three-dimensional force interactions than soft arteries
- Hydro-electromagnetic actuator effectively generates combined normal and shear forces for physiological pulse replication
Why it matters
Enables high-fidelity haptic training and cardiovascular diagnostics by accurately capturing the multi-directional force cues physicians rely on during pulse assessment.
Abstract
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 hydro- electromagnetic 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.