Publications (18)3.64 Total impact
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ABSTRACT: Variable Impedance Actuators (VIA) have received increasing attention in recent years as many novel applications involving interactions with an unknown and dynamic environment including humans require actuators with dynamics that are not well-achieved by classical stiff actuators. This paper presents an overview of the different VIAs developed and proposes a classification based on the principles through which the variable stiffness and damping are achieved. The main classes are active impedance by control, inherent compliance and damping actuators, inertial actuators, and combinations of them, which are then further divided into subclasses. This classification allows for designers of new devices to orientate and take inspiration and users of VIA’s to be guided in the design and implementation process for their targeted application.Robotics and Autonomous Systems 01/2013; 61(12):1601–1614. · 1.16 Impact Factor
- Journal of the Robotics Society of Japan. 05/2012; Vol. 30(2012-05-No. 4):378-382.
Conference Proceeding: The DLR hand arm system[show abstract] [hide abstract]
ABSTRACT: An anthropomorphic hand arm system using variable stiffness actuation has been developed at DLR. It is aimed to reach its human archetype regarding size, weight and performance. The main focus of our development is put on robustness, dynamic performance and dexterity. Therefore, a paradigm change from impedance controlled, but mechanically stiff joints to robots using intrinsic variable compliance joints is carried out. Collisions of the rigid joint robot at high speeds with stiff objects induce the energy too fast for an active controller to prevent damages. In contrast, passively compliant robots are able to temporarily store energy. In this case the resulting internal forces applied to the robot structure and the drive trains are reduced. Furthermore, the energy storage allows to outperform the dynamics of stiff robots. The hand drives and the electronics are completely integrated within the forearm. Extremely miniaturized electronics have been developed to drive the 52 motors of the system and interface their sensors. Several variable stiffness actuation principles used in the arm joints and the hand are presented. The paper highlights the different requirements that they have to fulfill. A first test of the systems robustness and dynamics has been performed by driving nails with a grasped hammer and is demonstrated in the attached video.Robotics and Automation (ICRA), 2011 IEEE International Conference on; 06/2011
Conference Proceeding: Development of a biped robot with torque controlled joints[show abstract] [hide abstract]
ABSTRACT: This paper gives an overview of the development of a novel biped walking machine. The robot is designed as an experimental system for studying biped locomotion based on torque controlled joints. As an underlying drive technology, the torque controlled joint units of the DLR-KUKA-Lightweight-Robot are employed. The relevant design choices for using this technology in a biped robot with integrated joint torque sensors are highlighted and some first experimental results using a conventional ZMP based control scheme are discussed.Humanoid Robots (Humanoids), 2010 10th IEEE-RAS International Conference on; 01/2011
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ABSTRACT: The mobile humanoid Rollin'Justin is a versatile experimental platform for research in manipulation tasks. Previously, different state of the art control methods and first autonomous task execution scenarios have been demonstrated. In this video two new applications with challenging task requirements are presented. One is the catching of one or even two flying balls using all of Justin's degrees of freedom. The other is the autonomous preparation of coffee. Both applications need adequate sensors to support local referencing. The required precision in position and timing is realized in software, using the sensor information, taking the varying precision of Justin's kinematic sub-chains into account and handling all timings in sub-millisecond range.IEEE International Conference on Robotics and Automation, ICRA 2011, Shanghai, China, 9-13 May 2011; 01/2011
Conference Proceeding: The DLR FSJ: Energy based design of a variable stiffness joint.[show abstract] [hide abstract]
ABSTRACT: Bringing mechanically compliant joints to robots is in the focus of interest world wide, especially in the humanoid robotics community. Variable Stiffness Joints (VSJ) promise to gain a high performing and robust robotic system. The presented DLR Floating Spring Joint (FSJ) is a VSJ module designed for the first 4 axes of the anthropomorphic DLR Hand Arm System. The DLR Hand Arm System aims to match the skills of its natural archetype. For this purpose, the joints have to be extremely compact to fit into the arm. At the same time they require a high power density in order to approximate the human arm skills. The new DLR FSJ is designed completely from an energy based point of view. This addresses not only energy efficient components and low friction design, but also that the potential energy of the spring is used as good as possible. A demonstration of robustness is given by the investigation of a blunt impact to the tip of the arm.IEEE International Conference on Robotics and Automation, ICRA 2011, Shanghai, China, 9-13 May 2011; 01/2011
Conference Proceeding: New insights concerning intrinsic joint elasticity for safety[show abstract] [hide abstract]
ABSTRACT: In this paper we present various new insights on the effect intrinsic joint elasticity has on safety in pHRI. We address the fact that the intrinsic safety of elastic mechanisms has been discussed rather one sided in favor of this new designs and intend to give a more differentiated view on the problem. An important result is that intrinsic joint elasticity does not reduce the Head Injury Criterion or impact forces compared to conventional actuation with some considerable elastic behavior in the joint, if considering full scale robots. We also elaborate conditions under which intrinsically compliant actuation is potentially more dangerous than rigid one. Furthermore, we present collision detection and reaction schemes for such mechanisms and verify their effectiveness experimentally.Intelligent Robots and Systems (IROS), 2010 IEEE/RSJ International Conference on; 11/2010
Conference Proceeding: On joint design with intrinsic variable compliance: derivation of the DLR QA-Joint[show abstract] [hide abstract]
ABSTRACT: In this paper we introduce a classification of intrinsically compliant joint mechanisms. Furthermore, we outline design considerations for realizing such devices in order to match the requirements for robust and performant actuation. Based on this elaboration, a new design concept is presented, the DLR QA-Joint. Its performance is investigated by various experiments, covering velocity increase using the elastic energy, joint protection capabilities, and control performance.Robotics and Automation (ICRA), 2010 IEEE International Conference on; 06/2010
- Automatisierungstechnik. 01/2010; 58:670-680.
Conference Proceeding: Dynamic modelling and control of variable stiffness actuators.[show abstract] [hide abstract]
ABSTRACT: After briefly summarizing the mechanical design of the two joint prototypes for the new DLR variable compliance arm, the paper exemplifies the dynamic modelling of one of the prototypes and proposes a generic variable stiffness joint model for nonlinear control design. Based on this model, the design of a simple, gain scheduled state feedback controller for active vibration damping of the mechanically very weakly damped joint is presented. Moreover, the computation of the motor reference values out of the desired stiffness and position is addressed. Finally, simulation and experimental results validate the proposed methods.IEEE International Conference on Robotics and Automation, ICRA 2010, Anchorage, Alaska, USA, 3-7 May 2010; 01/2010
- ISR/ROBOTIK 2010, Proceedings for the joint conference of ISR 2010 (41st Internationel Symposium on Robotics) und ROBOTIK 2010 (6th German Conference on Robotics), 7-9 June 2010, Munich, Germany - Parallel to AUTOMATICA; 01/2010
- Automatisierungstechnik. 01/2010; 58:622-629.
Conference Proceeding: Anthropomorphic Soft Robotics - From Torque Control to Variable Intrinsic Compliance.[show abstract] [hide abstract]
ABSTRACT: The paper gives an overview on the developments at the German Aerospace Center DLR towards anthropomorphic robots which not only try to approach the force and velocity performance of humans, but also have similar safety and robustness features based on a compliant behaviour.We achieve this compliance either by joint torque sensing and impedance control, or, in our newest systems, by compliant mechanisms (so called VIA - variable impedance actuators), whose intrinsic compliance can be adjusted by an additional actuator. Both approaches required highly integrated mechatronic design and advanced, nonlinear control and planning strategies, which are presented in this paper.Robotics Research - The 14th International Symposium, ISRR 2009, August 31 - September 3, 2009, Lucerne, Switzerland; 01/2009
Article: Soft robotics[show abstract] [hide abstract]
ABSTRACT: In this article, we gave an overview on the DLR activities related to two approaches for the realization of soft robotics: actively torque-controlled LWRs and VSA. On the basis of our experience with torque-controlled robots, we presented an analysis on expected advantages and also disadvantages of VSA actuators. Furthermore, two VSA joint designs motivated by this analysis were presented. Torque-controlled robots currently represent a technology mature enough for the market, but we believe that impressive research progress can be expected in the area of VSA-actuated robots in the next decade.IEEE Robotics & amp amp Automation Magazine 10/2008; · 2.48 Impact Factor
Conference Proceeding: Human motion range data optimizes anthropomorphic robotic hand-arm system design[show abstract] [hide abstract]
ABSTRACT: At the Institute of Robotics and Mechatronics of the German Aerospace Center (DLR Oberpfaffenhofen), a robotic hand-arm system is being developed, which will consist of a 19 active degree-of-freedom (DoF) hand and a 7 active DoF flexible arm based on antagonistic drive principles. It is targeted to mimic human hand and arm motion as closely as possible, taking kinematic as well as dynamic ranges into account. In the development of such a highly anthropomorphic hand- arm system, the motion of the human arm plays a key role. While the study of kinematic and dynamic ranges in humans has been done in various sources in litera- ture, none of these are however directly applicable to the developed robotic system. We approached this problem by using RAMSIS data recorded at the Department of Ergonomics at the technical university of Munich. By creating a three-dimensional multi-mode visualisation tool, these data were made available for laying out the dimensions and localisations of the 52 actuators that control the hand-arm system.9th International Conference on Motion and Vibration Control; 09/2008
- IEEE Robotics and Automation Magazine. 01/2008; 15(2008-3):20-30.
Conference Proceeding: A Humanoid Two-Arm System for Dexterous ManipulationIEEE-RAS; 01/2007
Conference Proceeding: Eine neue Generation von Leichtbau-Robotern mit mehrfingrigen HändenROBOTIK 2002, Forum am Schlosspark, Ludwigsburg, 19./20. Juni 2002; 01/2002
German Aerospace Center (DLR)
Köln, North Rhine-Westphalia, Germany
- Institute of Robotics and Mechatronics