Hierarchical framework for mobile robots to effectively and autonomously explore unknown environments.

Achieving efficient and safe autonomous exploration in unknown environments is an urgent challenge to be overcome in the field of robotics. Existing exploration methods based on random and greedy strategies cannot ensure that the robot moves to the unknown area as much as possible, and the exploration efficiency is not high. In addition, because the robot is located in an unknown environment, the robot cannot obtain enough information to process the surrounding environment and cannot guarantee absolute safety. To improve the efficiency and safety of exploring unknown environments, we propose an autonomous exploration motion planning framework that is divided into the exploration and obstacle avoidance levels. The two levels are independent and interconnected. The exploration level finds the optimal frontier target point in the global scope based on the forward filtering angle and cost function, attracting the robot to move to the unknown area as much as possible, and improving the exploration efficiency; the obstacle avoidance level establishes a scenario-speed conversion mechanism, and the target point and obstacle information are weighed to realise dynamic motion planning and completes obstacle avoidance control, and ensures the safety of exploration. Experiments in different simulation scenarios and real environments verify the superiority of the method. Results show that our method is superior to the existing methods. • An autonomous exploration method for a car-like mobile robot on the ground is designed. Even if the degree of freedom of exploration on the ground is limited and the process is more difficult. • The method is an interconnected and independent framework, including the exploration and the obstacle avoidance levels, both of which are dynamically expanded in the re-planning step. • The purpose of the exploration level is to provide the robot with a clear exploration direction, so that the robot can move to the unknown area as much as possible. • The obstacle avoidance level processes the robot's local environment in real time, it provides the robot with exploration power and ensures the safety of the exploration process. [ABSTRACT FROM AUTHOR]