Implementation of two robotic flagmen controlled by CAN messages to increase the safety of human workers in road maintenance

Abstract

Commonly, the improper signaling in road construction zones is the cause of different accidents to drivers, pedestrians, and road construction workers. The signaling used when a vehicle is approaching a repairing section could be classified into two classes: stationary or active. Nevertheless, active warning systems have demonstrated to reduce accidents in road work zones. Within the active signaling class we have: portable changeable message sign, flashing arrow signs, flagman, to mention some. This paper describes the implementation of two robotic flagmen controlled by the Controller Area Network (CAN) protocol. Each robotic flagman can perform four different actions: speed reduction (right and left) and lane change (right and left). The electronic circuitry and mechanical motors of the two robotic flagmen have the option to be powered by a solar charging system considering working zones where there is no access to the electric grid. The solar charging system guarantees a sufficient electrical power supply for night conditions operations. Also, the CAN protocol can be used to monitor the correct operability of the robotic flagmen thus eliminating the need to incorporate more expensive electronic devices such as cameras. The hardware combination in the control, monitoring, and solar charging system allow us to propose a low-cost practical implementation. The results of our implementation show that the longest response time of the robot is less than 850 ms once that the CAN message has been sent to the network. This demonstrates that our proposal can meet real-time implementation requirements.