A novel tactile probe with applications in biomedical robotics

In this research, sensitivity of a novel tactile probe was investigated experimentally and theoretically. These probes are made from three different parts, a rigid Plexiglas as support and two different compressible materials. As the sensing elements, two piezoelectric films of PVDF are incorporated into the probe and the combination of the resulting output voltages is related to the object softness. Depending on the softness of the sensed objects, there is a distinct difference between the output voltages. Harder objects tend to manifest waveforms with higher peaks and with steeper rises at the start of the tests. We made use of these important features and conducted a number of tests in order to analyze the sensitivity of the designed probe. A mathematical model based on the properties of various elements in the tactile probe is developed, which could reasonably predict the general performance of the system. The effects of different parameters such as, softness of the two compressible sections of the probe, their thickness, and their corresponding area ratios are tested experimentally. Using the developed model, the experimental results are predicted with good accuracy and the discrepancy is found to be within the acceptable range. This prototype has applications in determining the softness of biological tissues/objects both in routine clinical examinations and during surgeries.