Optical Flow Based Mobile Robot Obstacle Avoidance Method in Unstructured Environment

In order to solve the obstacle avoidance problem in complex unstructured environment, inspired by the optical flow navigation strategies of insects, an algorithm of visual obstacle avoidance for autonomous mobile robot was developed in this paper, which is suitable for complex unstructured environment. In order to reduce the influence of illumination changes and noise, improve the calculation accuracy and robustness of the optical flow algorithm, the gradient constancy assumption was introduced and the local was weighted. And the flow divergence was used to calculate the relative depth time-to-contact (TTC). Then an obstacle map was constructed based on the TTC. When robots were at risk of collision with the obstacles, the heading direction decision algorithm was designed for robot to choose the optimal direction. Simulation and physical experiments were done in this paper. Experimental results show that the presented method can guarantee a mobile robot wander without collision in unknown complex unstructured environments.