Arne Roennau

Design and kinematics of a biologically-inspired leg for a six-legged walking machine

Legged locomotion is a fascinating form of motion. Almost all legged robotic systems are biologically-inspired by some kind of role model. The stick insect and cockroach are two of the most popular role models in the field of six-legged walking robots. Although, their legs have at least four degrees of freedom, most robotic systems, which are biologically-inspired by these insects, come along with only three joints in each leg. In this paper we will present a new leg design with four degrees of freedom for the six-legged walking machine LAURON. This enlarges the workspace of our leg significantly compared to previous leg generations and makes it very similar to the leg of the stick insect. With the additional rotational fourth joint the kinematic structure becomes redundant. The inverse kinematics for this redundant structure is solved in a very efficient way by benefiting from the orientational redundancy.

LAURON V: A versatile six-legged walking robot with advanced maneuverability

Adaptive multi-legged walking robots are predestined to be applied in rough and hazardous terrain. Their walking and climbing skills allow them to operate at places that are unreachable for most wheeled vehicles. In this paper, we present the design and development of the new six-legged walking robot LAURON V with its improved kinematics and robust mechanical structure. Each leg has four independent joints that enable LAURON to cope with steep inclines, large obstacles and makes it possible to manipulate objects with its front legs. Autonomy, robustness and a large payload capacity together with its impressive terrain adaptability make LAURONV highly suitable for all kinds of field applications.

Modular robots for on-orbit satellite servicing

Today satellites are mostly monolithic systems and offer hardly any facilities to facilitate servicing or maintenance. Consequently, no servicer satellites are present as well. In this work, supported by the German Space Agency, we propose a modular concept for satellites based on standardized building blocks. These can be replaced in orbit requiring significantly less manipulation skills than ordinary repair missions would need. The building blocks could be replaced using robot satellites instead of sending astronauts on maintenance missions as has been performed few times in the past. The possible benefits are numerous: the concept enables cheaper and faster development of satellites, it enables repair missions extending the life expectancy of satellites by replacing damaged blocks or those run out of fuel, and finally old satellites can be refitted for new missions, reducing space debris and the cost of launching new systems. Developing our concept, we faced the same challenges known from modular robots on earth: interfaces had to be developed for connecting blocks, a distributed software architectures was needed, and algorithms were necessary which calculate suitable configurations of blocks according to given constraints. In this paper we will present solutions from which a concept of a modular satellite system emerges which is strongly inspired by earthbound heterogeneous robotic systems. We will complete the paper with thoughts on the servicing itself and on setting up maintenance infrastructures in the earth orbit.

LAURON V: OPTIMIZED LEG CONFIGURATION FOR THE DESIGN OF A BIO-INSPIRED WALKING ROBOT

Walking robots are fascinating, but also complex mechatronic systems. Typical six-legged robots have at least 18 joints and therefore come along with a huge design space. This design challenge can be addressed by applying technical analyzes and optimization methods or following the design of biological role models. The design of the new six-legged walking robot LAURON V employs both approaches. An additional rotational joint was added to the bio-inspired leg design of the previous LAURON generation. In this work we present the combination methods of three optimization that were developed to optimize the leg configuration. The resulting leg mounting angles are compared to biological leg configuration of the stick insect.

Unified GPU voxel collision detection for mobile manipulation planning

This paper gives an overview on our framework for efficient collision detection in robotic applications. It unifies different data structures and algorithms that are optimized for Graphics Processing Unit (GPU) architectures. A speed-up in various planning scenarios is achieved by utilizing storage structures that meet specific demands of typical use-cases like mobile platform planning or full body planning. The system is also able to monitor the execution of motion trajectories for intruding dynamic obstacles and triggers a replanning or stops the execution. The presented collision detection is deployed in local dynamic planning with live pointcloud data as well as in global a-priori planning. Three different mobile manipulation scenarios are used to evaluate the performance of our approach.

Reactive posture behaviors for stable legged locomotion over steep inclines and large obstacles

Multi-legged walking robots often make use of sophisticated control architectures to play their strengths in rough and unknown environments. The adaptability of these robots is an essential skill to achieve the maneuverability and autonomy needed in their application fields. In this work we present a reactive control approach for the hexapod LAURONV, which enables it to overcome large obstacles and steep slopes without any knowledge about the environment. A key to this success can also be seen in the increased kinematic adaptability due to the fourth rotational joint in the bio-inspired leg kinematics. An extended experimental evaluation shows that the reactive posture behaviors are able to create an effective and efficient locomotion in challenging environments.

A multi-resolution 3-D environment model for autonomous planetary exploration

A key skill for autonomous exploration and inspection missions is the ability to find safe and traversable paths within previously unknown environments. We present an approach for mapping typical environments encountered by autonomous planetary exploration robots, a pre-interpreted multi-resolution 3-D environment model generated from point cloud data, and a hybrid planner for basically any kind of mobile robot. Our system builds upon and enhances freely available standard frameworks such as ROS and OMPL. We present results of our system applied to our six-legged walking robot LAURON V, showing the progression from individual 3-D point clouds to a rich environment model queried by an RRT*-based planner to find and adapt a feasible and optimal path.

Hardware and software architecture of the bimanual mobile manipulation robot HoLLiE and its actuated upper body

We present our recent work on the soft- and hardware design of the bimanual mobile manipulation platform HoLLiE that is equipped with an actuated upper body. The goal was to develop a robust but extensible robot with a non-intimidating abstract anthropomatic appearance based on a combination of industrial robotic components and intelligent mechatronics. With a range of different sensors and a highly articulated body HoLLiE can handle everyday objects, interact with humans in multiple ways and therefore be employed in various service robotic scenarios. We demonstrate the usability of our concept by quantifying the workspace and its stability and also briefly describe the software components.

Connecting Artificial Brains to Robots in a Comprehensive Simulation Framework: The Neurorobotics Platform

Combined efforts in the fields of neuroscience, computer science, and biology allowed to design biologically realistic models of the brain based on spiking neural networks. For a proper validation of these models, an embodiment in a dynamic and rich sensory environment, where the model is exposed to a realistic sensory-motor task, is needed. Due to the complexity of these brain models that, at the current stage, cannot deal with real-time constraints, it is not possible to embed them into a real-world task. Rather, the embodiment has to be simulated as well. While adequate tools exist to simulate either complex neural networks or robots and their environments, there is so far no tool that allows to easily establish a communication between brain and body models. The Neurorobotics Platform is a new web-based environment that aims to fill this gap by offering scientists and technology developers a software infrastructure allowing them to connect brain models to detailed simulations of robot bodies and environments and to use the resulting neurorobotic systems for in silico experimentation. In order to simplify the workflow and reduce the level of the required programming skills, the platform provides editors for the specification of experimental sequences and conditions, environments, robots, and brain–body connectors. In addition to that, a variety of existing robots and environments are provided. This work presents the architecture of the first release of the Neurorobotics Platform developed in subproject 10 “Neurorobotics” of the Human Brain Project (HBP).1 At the current state, the Neurorobotics Platform allows researchers to design and run basic experiments in neurorobotics using simulated robots and simulated environments linked to simplified versions of brain models. We illustrate the capabilities of the platform with three example experiments: a Braitenberg task implemented on a mobile robot, a sensory-motor learning task based on a robotic controller, and a visual tracking embedding a retina model on the iCub humanoid robot. These use-cases allow to assess the applicability of the Neurorobotics Platform for robotic tasks as well as in neuroscientific experiments.

KAIRO 3: A modular reconfigurable robot for search and rescue field missions

Search and rescue field missions, especially in environments which are dangerous for humans, increasingly requires the usage of robust and flexible robots. We describe the development of the modular reconfigurable robot KAIRO 3 focusing on applications in search and rescue, inspection and maintenance. After a short retrospect of previous generations of modular robots, the latest design of KAIRO 3 is presented. In particular, enhancements of the mechatronics and the control software are shown. Furthermore, the necessity to increase the flexibility of search and rescue robots will be demonstrated. To comply with this requirement, we utilized reconfiguration and adaptation of modular robots. Finally, the field results of applying KAIRO 3 at a civil protection field exercise are discussed.