Experimental validation of a polyvinylidene fluoride sensing element in a tactile sensor.

A tactile sensor for robotic applications is described, inspired by the mechanoreceptors in the glabrous skin of the human hand, in order to replicate the sensory function of both slow adapting and fast adapting mechanoreceptors. Strain gauges were used for the slow adapting receptors, and polyvinylidene fluoride (PVDF) film was used to replicate the fast adapting receptors. A finite element analysis (FEA) model was used to predict the output response of the PVDF film, and verified experimentally. The PVDF film was observed to respond linearly to mechanical stress and exhibited increased gain at higher frequencies. "Ramp and hold" stimuli were applied to the tactile unit sensor, and the PVDF film only responded at contact onset and offset, similar to the response of fast adapting receptors. The PVDF acted as a dynamic sensing element for the proposed tactile sensor unit.

Experimental validation of a tactile sensor model for a robotic hand.

We describe a tactile sensor for a robotic hand, based on the mechanoreceptors in the glabrous skin of the human hand to replicate the sensory function of both slow adapting and fast adapting receptors. Strain gauges are used for the slow adapting receptors, and polyvinylidene fluoride (PVDF) film was used to replicate the function of the fast adapting receptors. One unit sensor consisted of four strain gauges and a single PVDF film, embedded beneath a square protrusion. The protrusion helped localize the applied force onto the region or 'receptive field' of the sensing unit. Strain gauges were orientated to enable the unit sensor to identify the tri-axial force components. Multiple linear regression was used to predict the components of force. The regression model with interaction terms gave good prediction with mean percentage errors of less than 15% for each force component.