Spline-Based Robot Trajectory Generation Using the Dynamic Window Approach

Many path planning systems for mobile robots today rely on a combination of waypoint navigation and reactive collision avoidance for motion control. Generally, such systems are not able to reliably produce smooth and predictable navigation behavior as it is required, e.g., when robots and humans operate in the same environment. In contrast, spline-based motion planning techniques can generate smooth goal-directed trajectories. But for most robot drives a subsequent control step is required that actually steers the robot along the desired trajectory. In this article we propose a control approach that is based on the Dynamic Window Approach (DWA). Classical DWA controls the robot's velocities in order to steer it to a given goal location, avoiding collisions along the way. Here, the approach is used to follow a given spline path as close as possible, while collision avoidance is already handled in the spline-based motion planning. Thus expensive collision checks can be omitted from the velocity search of the DWA and the gained processing time allows computing velocity controls several time-steps ahead, resulting in improved path following. We demonstrate the benefit of this approach in simulation experiments and show its applicability for a real robot.