Dynamic tactility by position-encoded spike spectrum.

In fast and transient somatosensory processing, the relative timing of the selected spikes is more important than the spike frequency because the ensemble of the first spikes in the spike trains encodes the dynamic tactile information. Here, inspired by the functional effectiveness of the selected spikes, we propose an artificial dynamic sensory system based on position-encoded spike spectrum. We use a mixed ion-electron conductor to generate a potential spike signal. We design artificial receptors that have different ion relaxation times (τ); thus, a sequence of the spikes from the receptors creates a spike spectrum, providing the spatial information (position and motion trace) and the temporal information (speed and dynamic contact area). The artificial receptors can be incorporated by as much as 132/square centimeters by using only two global signal addressing lines for sensor operation. Structural simplicity of the device opens the possibility of scalable fabrication with dense receptor integration. With computational decoding of the position-encoded spike spectrum, the artificial sensory system can recognize complicated dynamic motions in real time. The high-resolution spatiotemporal tactile perception in the ionic artificial sensory system enables the real-time dynamic robotic manipulation.