Simon Kielhöfer

A Humanoid Two-Arm System for Dexterous Manipulation

This paper presents a humanoid two-arm system developed as a research platform for studying dexterous two-handed manipulation. The system is based on the modular DLR-Lightweight-Robot-III and the DLR-Hand-II. Two arms and hands are combined with a three degrees-of-freedom movable torso and a visual system to form a complete humanoid upper body. In this paper we present the design considerations and give an overview of the different sub-systems. Then, we describe the requirements on the software architecture. Moreover, the applied control methods for two-armed manipulation and the vision algorithms used for scene analysis are discussed

The 3D-Modeller: A Multi-Purpose Vision Platform

This paper deals with the concept and implementation of a multi-purpose vision platform. In robotics, numerous applications require perception. A multi-purpose vision platform suited for object recognition, cultural heritage preservation and visual servoing at the same time is missing. In this work, we draw attention to the design principles for such a vision platform. We present its implementation, the 3D-modeller. In specifying and combining multiple sensors, laser-range scanner, laser-stripe profiler and stereo vision, we derive the required mechanical and electrical hardware design. The concepts for synchronization and communication round offs our approach. Precision and frame rate are presented. We illustrate the versatility of the 3D-modeller by addressing four applications: 3D-modeling, exploration, tracking and object recognition. Due to its low weight and generic mechanical interface, it can be mounted on industrial robots, humanoids, or free-handed as well. The 3D-modeller is flexibly applicable, not only in research but also in industry, especially in small batch assembly.

The self-referenced DLR 3D-modeler

In the context of 3-D scene modeling, this work aims at the accurate estimation of the pose of a close-range 3-D modeling device, in real-time and passively from its own images. This novel development makes it possible to abandon using inconvenient, expensive external positioning systems. The approach comprises an ego-motion algorithm tracking natural, distinctive features, concurrently with customary 3-D modeling of the scene. The use of stereo vision, an inertial measurement unit, and robust cost functions for pose estimation further increases performance. Demonstrations and abundant video material validate the approach.

DLR VR-SCAN: A versatile and robust miniaturized laser scanner for short range 3D-modelling and exploration in robotics

Precise and robust perception of the environment is crucial for highly integrated and autonomous robot systems. In this paper the dedicated design of a triangulation based laser range scanner optimized for 3D-modelling and autonomous exploration in robotics is presented. The presented laser scanner design is based on an extremely small MEMS scan head permitting a compact, lightweight and highly integrated implementation allowing for hand-eye operation. Special capabilities like variable range and confidence rating of the measuring values increase robustness. The design considerations and a prototype are described and experimental results are presented.

Portable 3-D modeling using visual pose tracking

Abstract This work deals with the passive tracking of the pose of a close-range 3-D modeling device using its own high-rate images in realtime, concurrently with customary 3-D modeling of the scene. This novel development makes it possible to abandon using inconvenient, expensive external trackers, achieving a portable and inexpensive solution. The approach comprises efficient tracking of natural features following the Active Matching paradigm, a frugal use of interleaved feature-based stereo triangulation, visual odometry using the robustified V-GPS algorithm, graph optimization by local bundle adjustment, appearance-based relocalization using a bank of parallel three-point-perspective pose solvers on SURF features, and online reconstruction of the scene in the form of textured triangle meshes to provide visual feedback to the user. Ideally, objects are completely digitized by browsing around the scene; in the event of closing the motion loop, a hybrid graph optimization takes place, which delivers highly accurate motion history to refine the whole 3-D model within a second. The method has been implemented on the DLR 3D-Modeler; demonstrations and abundant video material validate the approach. These types of low-cost systems have the potential to enhance traditional 3-D modeling and conquer new markets owing to their mobility, passivity, and accuracy.