16 research outputs found

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    The inverse kinematics problem is formulated as a parameterized autonomous dynamical system problem, and respective analysis is carried out. It is shown that a singular point of work space can be mapped either as a critical or a noncritical point of the autonomous system, depending on the direction of approach to the singular point. Making use of the noncritical mapping, a closed-loop kinematic controller with asymptotic stability and velocity limits along degenerate singular or near-singular paths is designed. The authors introduce a specific type of motion along the reference path, the so-called natural motion. This type of motion is obtained in a straightforward manner from the autonomous dynamical system and always satisfies the motion constraint at a singular point. In the vicinity of the singular point, natural motion slows down the end-effector speed and keeps the joint velocity bounded. Thus, no special trajectory replannin

    An Intelligent Vision-only Operator Interface for Dexterous Robots

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    The development of a vision-only intelligent interface for dexterous robots is described, capable of tracking operator motions: evaluating trajectory feasibility, and providing visual feedback to the operator. This interface analyses the operator's arm motion for safety, and then converts it into trajectory commands for a mechanical arm. Potentially dangerous situations, such as singularity and self collision, are displayed to the operator as graphical icons superimposed over the robot video images. The paper summarizes the main features of the current implementation, presents the approach developed for singularity identification and describes the performance of the demonstration prototype
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