Seminar of Boris Lau (University of Freiburg)

Speaker:   Boris Lau, University of Freiburg
Friday May 6 2011

Title: Online Generation of Kinodynamic Trajectories

Time and location: Friday, May 6, 2011, 10:00, Aula Magna

We present an approach to kinodynamic motion planning for mobile robots. From a collision-free straight-line path we generate a spline-based approximation and compute a velocity profile that considers the kinodynamic platform constraints. The shape of the initial trajectory is iteratively optimized to reduce user-defined costs like traversal time or energy efficiency.

As a key contribution we propose a novel spline-based path representation that realizes curvature-continuous joins of trajectory segments, even if trajectory pieces are replaced to react to unmapped obstacles. It provides a compact set of meaningful higher-level parameters to the optimization, e.g., the location of waypoints and wideness of curves.

Omnidirectional holonomic robots can rotate independently from translation which substantially increases their action space. To exploit their capabilities we extend our framework in order to specify where on the path the robot rotates. This enables rotational behaviors in the full spectrum between turns on the spot only and uninterrupted rotation along the path. Furthermore, the orientational behavior can be varied between the possibly conservative settings of the initial path and minimized overall rotation.

Experiments carried out on real robots with differential, synchro, and holonomic drives demonstrate our system's capability to generate smooth, precise, and predictable motion. They have been conducted on predefined benchmark routes, in difficult situations like narrow passages, and even in populated environments.

Boris Lau is a PhD student with Prof. Wolfram Burgard at the Autonomous Intelligent Systems Group, University of Freiburg (Germany). His research interests are robot navigation in populated environments. He received his diploma degree in computer science from the Technical University of Ilmenau in 2007. His prior work comprises vision based robotics at the Laboratory for Active and Attentive Vision at York University (Canada), as well as visual tracking and developmental modeling at the Cognitive Systems and Cognition Laboratory at University of California, San Diego (USA).