Joachim Tesch

A novel framework for closed-loop robotic motion simulation - part I: Inverse kinematics design

This paper considers the problem of realizing a 6-DOF closed-loop motion simulator by exploiting an anthropomorphic serial manipulator as motion platform. Contrary to standard Stewart platforms, an industrial anthropomorphic manipulator offers a considerably larger motion envelope and higher dexterity that let envisage it as a viable and superior alternative. Our work is divided in two papers. In this Part I, we discuss the main challenges in adopting a serial manipulator as motion platform, and thoroughly analyze one key issue: the design of a suitable inverse kinematics scheme for online motion reproduction. Experimental results are proposed to analyze the effectiveness of our approach. Part II [1] will address the design of a motion cueing algorithm tailored to the robot kinematics, and will provide an experimental evaluation on the chosen scenario: closed-loop simulation of a Formula 1 racing car.

A novel framework for closed-loop robotic motion simulation - part II: Motion cueing design and experimental validation

This paper, divided in two Parts, considers the problem of realizing a 6-DOF closed-loop motion simulator by exploiting an anthropomorphic serial manipulator as motion platform. After having proposed a suitable inverse kinematics scheme in Part I [1], we address here the other key issue, i.e., devising a motion cueing algorithm tailored to the specific robot motion envelope. An extension of the well-known classical washout filter designed in cylindrical coordinates will provide an effective solution to this problem. The paper will then present a thorough experimental evaluation of the overall architecture (inverse kinematics + motion cueing) on the chosen scenario: closed-loop simulation of a Formula 1 racing car. This will prove the feasibility of our approach in fully exploiting the robot motion capabilities as a motion simulator.

The CableRobot simulator large scale motion platform based on cable robot technology

This paper introduces the CableRobot simulator, which was developed at the Max Planck Institute for Biological Cybernetics in cooperation with the Fraunhofer Institute for Manufacturing Engineering and Automation IPA. The simulator is a completely novel approach to the design of motion simulation platforms in so far as it uses cables and winches for actuation instead of rigid links known from hexapod simulators. This approach allows to reduce the actuated mass, scale up the workspace significantly, and provides great flexibility to switch between system configurations in which the robot can be operated. The simulator will be used for studies in the field of human perception research and virtual reality applications. The paper discusses some of the issues arising from the usage of cables and provides a system overview regarding kinematics and system dynamics as well as giving a brief introduction into possible application use cases.

It is all me: the effect of viewpoint on visual–vestibular recalibration

Participants performed a visual–vestibular motor recalibration task in virtual reality. The task consisted of keeping the extended arm and hand stable in space during a whole-body rotation induced by a robotic wheelchair. Performance was first quantified in a pre-test in which no visual feedback was available during the rotation. During the subsequent adaptation phase, optical flow resulting from body rotation was provided. This visual feedback was manipulated to create the illusion of a smaller rotational movement than actually occurred, hereby altering the visual–vestibular mapping. The effects of the adaptation phase on hand stabilization performance were measured during a post-test that was identical to the pre-test. Three different groups of subjects were exposed to different perspectives on the visual scene, i.e., first-person, top view, or mirror view. Sensorimotor adaptation occurred for all three viewpoint conditions, performance in the post-test session showing a marked under-compensation relative to the pre-test performance. In other words, all viewpoints gave rise to a remapping between vestibular input and the motor output required to stabilize the arm. Furthermore, the first-person and mirror view adaptation induced a significant decrease in variability of the stabilization performance. Such variability reduction was not observed for the top view adaptation. These results suggest that even if all three viewpoints can evoke substantial adaptation aftereffects, the more naturalistic first-person view and the richer mirror view should be preferred when reducing motor variability constitutes an important issue.

Personal Interfaces-To-Go: mobile devices for data exchange and interaction in heterogeneous visualization environments

In this paper we present the Personal Interfaces-To-Go (PI2GO) architecture, which uses mobile devices in support of interacting and exchanging data between heterogeneous scientific visualization systems. PI2GO is an approach to easily expand existing visualization system, with data communication capabilities, using standard XML-based web service technologies (SOAP). The mobile device software component of PI2GO is able to dynamically generate the user-interface, based on the available capabilities of the visualization system and also contains the necessary logic for the data exchange process. We describe the architecture of our system and the initial implementation for standard PDA hardware, which allows exchanging data between a semi-immersive volume visualization prototype application and a desk-top-based volume visualization product.

Studydesk: semi-immersive volumetric data analysis

The StudyDesk system provides a workbench environment that is well suited to work with multi-dimensional volumetric data in a semi-immersive virtual-reality setting. Using the StudyDesk system, we have implemented two example volume-rendering applications. The first visualises medical volumetric data using its implicit correspondence to physical space. The second is used to visualise and analyse sonar data described by time, range, bearing and frequency dimensions, in which correlations between sub-volumes is important. Therefore an abstract representation of the dataset is used to identify important regions in the data, which are then analysed using more traditional volume visualisation techniques. Interaction is implemented through the use of personal interaction props based on a pen and pad metaphor. Props include a transparent pen and pad that carry virtual shapes and a PDA system that is also used to transfer data and contexts between various systems.

Perception of emotional body expressions in narrative scenarios

People use body motion to express and recognise emotions. We investigated whether emotional body expressions can be recognised when they are recorded during natural narration, where actors freely express the emotional colouring of a story told. We then took only the upper body motion trajectories and presented them to participants in the form of animated stick figures. The observers were asked to categorise the emotions expressed in short motion sequences. The results show that recognition level of eleven emotions shown via upper body is significantly above chance level and the responses to motion sequences are consistent across observers.

StudyDesk: interactive data analysis and scientific visualization in a semi-immersive environment

We present a highly interactive large-scale visualization environment for performing the tasks of detection and classification of sonar contacts in a low signal to noise environment. The system described deals with simulated passive sonar data from an advanced towed array system, chosen for both the amount and high dimensionality typical of the data produced. Our prototype application employs a semi-immersive 3D display system, multiple and mixed modalities of interaction and feedback, and state-of-the-art volumetric visualization and abstraction techniques. Our two-stage approach seeks to use human talents, experience and intuition to leverage and direct high-performance computing resources. The first stage (search&detect) aims at providing advanced visualization and human/machine interface techniques to enable sonar operators to quickly and confidently detect contacts in low signal-to-noise dataspaces. In the second component (analyze&classify), we utilize a highly interactive volumetric representation of the tactical SensorSpace that the operator can interrogate using various visual and auditory cues. This presentation describes the application scenario, approach and implementation of the visualization environment and concludes with experiences, lessons learned, and future directions from both the interactive large-scale visualization as well as an application point of view.