Trajectory Planning of Autonomous Vehicles in Environments with Moving Obstacles

Abstract

This paper concerns the trajectory planning of autonomous vehicles roving in the environments with moving obstacles. The study develops a simple and efficient algorithm for trajectory planning based on the data obtained from range scanners. Obstacles in an unstructured environment may have complicated shapes and motion. The complexity of trajectory planning increases with the number of configuration parameters defining the envrionment. The way to simplify the algorithm of the trajectory planning is to approximate the shapes of both vehicle and obstacles. To the purpose, obstacles in our study are modeled mathematically as complementary sectors. They divide the workspace into forbidden area and feasible area. The representation could simulate any type of obstacles in a simpler manner.In general, the velocity of an autonomous vehicle has its maximum values. Under the consideration of velocity constraints, we obtain the feasible velocity regions of an autonomous vehicle for obstacle avoidance after removing the portions which make the vehicle move toward obstacles. In order to derive analgorithm, these feasible velocity regions corresponding to each obstacle are superimposed to find the instantaneous optimal velocity for the vehicle.The algorithm developed is able to guide a vehicle toward a specified target from a starting point safely and quickly. Finally, a simulation program has been developed to verify the proposed algorithm by using C language.