A new type of master robot for teleoperation is proposed. In the proposed master robot, several wires are stretched from a handle which is moved by a human operator. In this paper, the authors explain how many wires are necessary to control a handle with six degrees of freedom in a three dimensional space. Moreover, to feed forces from a slave robot to the handle, an algorithm to determine each wire tension is proposed. Finally, they show experimental results in which a handle is moved by seven wires in a three dimensional space

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In this paper, we present an inexpensive force feedback virtual reality system using a 3-DOF five-bar-linkage manipulator. The direct drive manipulator has a gravity balanced structure. An implicit force control strategy is used to determine the virtual force feedback. The effects of virtual wall and virtual free space controllers are studied. A graphics system is developed to provide the visual feedback to the user. Experimental results are presented to show the user interaction with a virtual wall and a virtual object

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Haptic interaction with virtual objects is typically tool mediated, or in alternative it constraints userpsilas body in someway, like it happens in exoskeletons that cannot be totally transparent. Encounter type haptic interfaces aim at hands free haptic interaction, that is more natural and can be applied in contexts in which the user moves in the space around the interface. This paper presents a system that allows a palm based haptic interaction in a large workspace using the principle of encountered haptics. The system is evaluated in a surface exploration task and compared against the same task performed with a standard haptic interface. In this type of task this type of interface is better suited, providing a smoother feedback to the hand during the movement over the surface.

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Haptic cues take on meaning as a function of the context in which they are experienced. In interaction with objects in the physical environment, the context always includes a mechanical contact, at which point force and motion variables can be identified, and across which power may flow. In interaction with objects in a virtual or remote environment, it is not necessary for the contact across which haptic responses are rendered to be the same as the contact at which exploratory actions are applied. In this paper, we ask whether force/motion coupling has a significant impact on manual performance or cognitive load. We conducted an experiment in which n=7 participants attempted, while acting through a teleoperator, to discriminate three objects by their stiffness under two conditions. In one condition physical force/motion coupling was present, in the other it was not. To assess cognitive load, we engaged participants in a simultaneous cognitive task that included a response time measure. Results indicated no difference in manual discrimination performance. After rejecting the datasets of three of our participants based on inconsistent strategy by condition, we observed a small, non-significant trend toward lower cognitive load in the condition with physical coupling. Establishing a robust trend will require additional participants. While results are preliminary, we offer our paradigm as an important direction for new inquiry into the distinctions and interrelationships between information and its presentation in various haptic interface applications. Our work is aimed in particular at developing haptic feedback for use in prosthetic applications.

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For many years, the production of intensively reared crustaceans in the United States has been assumed to be an economically attractive proposition. In the late 1970’s profitable culture of Homarus in the United States was believed possible upon the development of very large and technologically sophisticated facilities. Until recently, however, commercial development could not proceed due to the lack of essential biological information on reproduction and nutrition which would allow for the application of cost saving technology. Recently it has been shown that egg production in the female lobster can be induced by proper photoperiod manipulation. This finding suggests that with appropriate management practices the commercial culturist could be assured of a reliable supply of seed stock throughout the year. Development of a formulated pelletized diet which supports the growth of juvenile lobsters to adulthood is another recent advance. Although the rate of growth on this laboratory ration is still less than that achieved on a diet of natural food items, this ration serves as a foundation from which to proceed in the development of practical feeds. In addition to refining reproductive control and furthering feed development, at least three additional steps are seen as necessary before the potential of commercial lobster aquaculture can be reliably predicted. First, the existing economic model needs to be examined in light of research which has taken place since its original conception. It is likely that such an effort would lead to a refining of current ideas regarding commercial culture. Second, additional biological research is required to understand the nature of space restriction on growth. Reduction of the space requirement will undoubtedly allow for significant savings in the capital required for commercial facilities. Finally, it would appear to be prudent to validate an improved economic model at a scale appropriate to the envisioned commercial operation.

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