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Herbert Janssen

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5 papers

1 author row

IROS Conference 2009 Conference Paper

Decentralized planning for dynamic motion generation of multi-link robotic systems

Yuichi Tazaki
Hisashi Sugiura
Herbert Janssen
Christian Goerick

This paper presents a decentralized planning method for generating dynamic whole body motions of multilink robots including humanoids. First, a robotic system will be modeled as a general multi-body dynamical system. The planning problem of a multi-body system will then be formulated as a constraint resolution problem. The problem will be solved by means of an extended Gauss-Seidel method, which is capable of handling multiple constraint groups with different priorities. The method will be demonstrated in whole-body motion generation tasks of a humanoid, both in numerical simulations and in experiments using a real humanoid robot.

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IROS Conference 2009 Conference Paper

Instant prediction for reactive motions with planning

Hisashi Sugiura
Herbert Janssen
Christian Goerick

Reactive control and planning are complementary methods in robot motion control. The advantage of planning is the ability to find difficult solutions, optimize trajectories globally and not getting stuck in local minima but at higher computational cost. On the other hand, reactive control can handle dynamic or uncertain environments at low computational cost, but may get stuck in local minima.

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IROS Conference 2007 Conference Paper

Real-time collision avoidance with whole body motion control for humanoid robots

Hisashi Sugiura
Michael Gienger
Herbert Janssen
Christian Goerick

We propose a self collision avoidance system that superposes trajectories in order not only to protect the robot's hardware but also to enable continuous motions. The system runs in real-time so that the robot can work in an uncertain environment. It is based on virtual forces between close segments of the robot. The avoidance movements are blended with a whole body motion control in order to change the priority between target reaching and collision avoidance. The blending is performed autonomously without the necessity of external switching. Our method works both while the robot is standing and walking. Reaching motions from the front to the side of the body without the arm colliding with the body are possible. Even if the target is inside the body, the arm stops at the closest point to the target outside of the body. Our method can be used for other applications: We apply it to realizing a "body schema" and for "occlusion avoidance. "

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ICRA Conference 2007 Conference Paper

Visually Guided Whole Body Interaction

Bram Bolder
Mark Dunn
Michael Gienger
Herbert Janssen
Hisashi Sugiura
Christian Goerick

We describe a system for visual interaction developed for humanoid robots. It enables the robot to interact with its environment using a smooth whole body motion control driven by stabilized visual targets. Targets are defined as visually extracted "proto-objects" and behavior-relevant object hypotheses and are stabilized by means of a short-term sensory memory. Selection mechanisms are used to switch between behavior alternatives for searching or tracking objects as well as different whole body motion strategies for reaching. The decision between different motion strategies like reaching with right or left hand or with and without walking is made based on internal predictions that use copies of the whole-body control algorithm. The results show robust object tracking and a smooth interaction behavior that includes a large variety of whole-body postures.

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IROS Conference 2006 Conference Paper

Exploiting Task Intervals for Whole Body Robot Control

Michael Gienger
Herbert Janssen
Christian Goerick

This paper presents a whole body motion algorithm and shows some steps towards its feasibility in complex scenarios. We employ the framework of Liegeois, (1977) which solves the redundant inverse kinematics problem on velocity level. To make the controller suitable for a variety of different applications, task descriptors for the relative effector positions as well as a one-and two-dimensional attitude representation are proposed. The inverse kinematics are extended by allowing for "displacement intervals" which are formulated in task space. The proposed control scheme guarantees that the effector motion lies within the specified interval. However, the motion inside the interval is determined by optimization criteria, which can effectively be utilized to generate a more flexible and robust motion. We discuss an example and show simulation and experimental results on the humanoid robot ASIMO

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