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Available from: Uwe D. Hanebeck, Oct 04, 2015
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    ABSTRACT: The "steady hand" concept is a way of providing assistance for direct manipulation by applying constraints on the motion of a tool shared by a user and a robot. We explore in detail one family of constraints: virtual fixtures for use in path following tasks. Vision is used to sense the desired path, and then the robot encourages motion toward and along the path through a direction-based control law. This "soft" virtual fixture allows the user to move in other, non-preferred directions, maintaining the user's sense of autonomy and control. Experimental results show that user performance in assisted path following improves with virtual fixture augmentation, and differs with varying fixture compliance
    Intelligent Robots and Systems, 2001. Proceedings. 2001 IEEE/RSJ International Conference on; 02/2001
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    ABSTRACT: In the future, robots will have to assist human beings in the performance of several tasks. In order to achieve this goal, robots have to be able to follow human movement in a way that is transparent to the human operator. This paper presents a new method to make this cooperation more transparent. The method is based on an online variable impedance control using differentiation of the force as a natural sensor of human intention. This work will also demonstrate why velocity control should be used in the controller of a human-friendly robot rather than typical position control. The performance of the control scheme introduced here is also validated in an experimental cooperative drawing task involving a parallel manipulator and a human operator
    Second Joint EuroHaptics Conference and Symposium on Haptic Interfaces for Virtual Environment and Teleoperator Systems (WHC 2007), 22-24 March 2007, Tsukuba, Japan; 01/2007
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    ABSTRACT: Segmentation and recognition of operator-generated motions are commonly facilitated to provide appropriate assistance during task execution in teleoperative and human-machine collaborative settings. The assistance is usually provided in a virtual fixture framework where the level of compliance can be altered online, thus improving the performance in terms of execution time and overall precision. However, the fixtures are typically inflexible, resulting in a degraded performance in cases of unexpected obstacles or incorrect fixture models. In this paper, we present a method for online task tracking and propose the use of adaptive virtual fixtures that can cope with the above problems. Here, rather than executing a predefined plan, the operator has the ability to avoid unforeseen obstacles and deviate from the model. To allow this, the probability of following a certain trajectory (subtask) is estimated and used to automatically adjusts the compliance, thus providing the online decision of how to fixture the movement
    IEEE Transactions on Robotics 11/2006; 22(5-22):1029 - 1033. DOI:10.1109/TRO.2006.878976 · 2.43 Impact Factor
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