A new local path planner for nonholonomic mobile robot navigation in cluttered environments

Abstract

Presents a local path planner for mobile robots in an environment with obstacles, where the nonholonomic constraints are considered. This planner uses only the distance information between the robot and the obstacles, thus it is well adapted for a robot equipped with onboard sensors, such as ultrasonic sensors. The obstacles are mapped as linear constraints into the velocity space of the robot; since the obstacles constraints are linear, they form a convex subset which represents the velocities that the robot can use without collision with the objects. We call this convex subset the "feasible velocities polygon" (FVP). The planner is composed of two modules; the first one is based on an optimization problem, which is transformed into a minimal distance calculation problem, in the velocity space, between the FVP and a point, which represents the reference velocity obtained by considering the nonholonomic constraint, the second module, which is used when a dead-lock situation occurs, uses the FVP representation to find, locally, the best velocity to escape from the dead-lock. The major advantages of this method are the very short calculation time and a continuous stable behavior of the velocities. The results presented demonstrate the capabilities of the proposed method for solving the collision free path planning problem.