A Time Synchronization Protocol for Modular Robots

In this paper, we propose the Modular Robot Time Protocol (MRTP), a network-wide time synchronization protocol for modular robots. Our protocol achieves its performance by combining several mechanisms: central time master election, low-level time-stamping and clock skew compensation using linear regression. We evaluate our protocol on the Blinky Blocks hardware. Experimental results show that MRTP can potentially manage real systems composed of up to 27,775 Blinky Blocks. We observe that the synchronization precision depends on the hardware, the hop distance to the time master, the synchronization periods and the number of synchronization points used for the linear regressions. Furthermore, we show that our protocol is able to keep a Blinky Blocks system synchronized to a few milliseconds, using few network resources at runtime, even-though the Blinky Blocks hardware clocks exhibit very poor accuracy and resolution. Keywords Time synchronization, Modular robotic, Distributed embedded systems