DLR Crawler

Working towards a highly mobile, legged exploration robot, the DLR Crawler is a first experimental platform to test various control and gait algorithms as well as different approaches to vision-based navigation. The robot employs the fingers of DLR Hand II as legs, which offer a unique combination of high performance actuation and a broad range of integrated sensors.

The robot was first presented to the public in 2008.

Technical Data

System description

Aiming at terrestrial and extra-terrestrial exploration, all locomotion- and navigation-related algorithms developed for the DLR Crawler focus on robust autonomous operation in a priori unknown, GPS-denied environments. Based on findings from biology, the gait algorithm of the DLR Crawler employs a highly flexible, decentralized approach, wherein neighboring legs influence each other by inhibiting or exciting stepping motions. Thus, the gait of the DLR Crawler does not show a fixed pattern but rather emerges according to the commanded velocity and the interaction of the legs with the local environment. In addition, joint torque sensors provide valuable proprioceptive measurements that enable sensitive interaction with the terrain by compliance control. Thus, in combination with three simple reflexes, the robot is able to negotiate all obstacles within its walking height autonomously. Furthermore, the gait coordination immediately adapts to the loss of a leg while the robot easily maintains its stability. In order to navigate in unknown terrain a stereo camera head is mounted on the DLR Crawler. Using the semi-global-matching-based stereo vision algorithm developed at the institute, the robot assesses the terrain traversability and plans a path to a desired goal solely based on the information acquired by its on-board sensors.

Martin Görner German Aerospace Center Institute of Robotics and Mechatronics, Analysis and Control of advanced robotic systems Oberpfaffenhofen-Weßling Tel.: +49 8153 28-1089 Fax: +49 8153 28-1134