Integration of High-speed Visual and Tactile Sensors with Synchronization in a Sensor Network System

In this paper, we propose a data acquisition synchronization scheme for integrating 500-fps class high-speed networked visual and tactile sensors systems. In the proposed scheme, multiple sensor nodes including PCs are connected via Ethernet for data communication and for clock synchronization. The clocks of the PCs are synchronized over the network using Precision Time Protocol (PTP) with negligible errors of around a few microseconds. The trigger of each sensor is locally controlled based on the PC's clock locally provided in the node, and the clocks are globally synchronized over the network. An experimental system comprising a high-speed vision system, a high-speed tactile sensor, and two PCs was constructed, and the experimental results showed that the timing error between the sensor nodes for data acquisition was less than 15 microseconds, which is significantly smaller than the time interval of 2 milliseconds.