*Article* **Mapless Collaborative Navigation for a Multi-Robot System Based on the Deep Reinforcement Learning**

**Wenzhou Chen 1,†, Shizheng Zhou 1,†, Zaisheng Pan 1,2, Huixian Zheng <sup>2</sup> and Yong Liu 1,\***


Received: 25 August 2019; Accepted: 24 September 2019; Published: 9 October 2019

**Abstract:** Compared with the single robot system, a multi-robot system has higher efficiency and fault tolerance. The multi-robot system has great potential in some application scenarios, such as the robot search, rescue and escort tasks, and so on. Deep reinforcement learning provides a potential framework for multi-robot formation and collaborative navigation. This paper mainly studies the collaborative formation and navigation of multi-robots by using the deep reinforcement learning algorithm. The proposed method improves the classical Deep Deterministic Policy Gradient (DDPG) to address the single robot mapless navigation task. We also extend the single-robot Deep Deterministic Policy Gradient algorithm to the multi-robot system, and obtain the Parallel Deep Deterministic Policy Gradient (PDDPG). By utilizing the 2D lidar sensor, the group of robots can accomplish the formation construction task and the collaborative formation navigation task. The experiment results in a Gazebo simulation platform illustrates that our method is capable of guiding mobile robots to construct the formation and keep the formation during group navigation, directly through raw lidar data inputs.

**Keywords:** multi-robot; collaborative navigation; deep reinforcement learning
