378 research outputs found
Learned navigation in unknown terrains: A retraction method
The problem of learned navigation of a circular robot R, of radius delta (is greater than or equal to 0), through a terrain whose model is not a-priori known is considered. Two-dimensional finite-sized terrains populated by an unknown (but, finite) number of simple polygonal obstacles are also considered. The number and locations of the vertices of each obstacle are unknown to R. R is equipped with a sensor system that detects all vertices and edges that are visible from its present location. In this context two problems are covered. In the visit problem, the robot is required to visit a sequence of destination points, and in the terrain model acquisition problem, the robot is required to acquire the complete model of the terrain. An algorithmic framework is presented for solving these two problems using a retraction of the freespace onto the Voronoi diagram of the terrain. Algorithms are then presented to solve the visit problem and the terrain model acquisition problem
Probabilistic approach to physical object disentangling
Physically disentangling entangled objects from each other is a problem
encountered in waste segregation or in any task that requires disassembly of
structures. Often there are no object models, and, especially with cluttered
irregularly shaped objects, the robot can not create a model of the scene due
to occlusion. One of our key insights is that based on previous sensory input
we are only interested in moving an object out of the disentanglement around
obstacles. That is, we only need to know where the robot can successfully move
in order to plan the disentangling. Due to the uncertainty we integrate
information about blocked movements into a probability map. The map defines the
probability of the robot successfully moving to a specific configuration. Using
as cost the failure probability of a sequence of movements we can then plan and
execute disentangling iteratively. Since our approach circumvents only
previously encountered obstacles, new movements will yield information about
unknown obstacles that block movement until the robot has learned to circumvent
all obstacles and disentangling succeeds. In the experiments, we use a special
probabilistic version of the Rapidly exploring Random Tree (RRT) algorithm for
planning and demonstrate successful disentanglement of objects both in 2-D and
3-D simulation, and, on a KUKA LBR 7-DOF robot. Moreover, our approach
outperforms baseline methods
Connectivity-guaranteed and obstacle-adaptive deployment schemes for mobile sensor networks
Mobile sensors can relocate and self-deploy into a network. While focusing on the problems of coverage, existing deployment schemes largely over-simplify the conditions for network connectivity: they either assume that the communication range is large enough for sensors in geometric neighborhoods to obtain location information through local communication, or they assume a dense network that remains connected. In addition, an obstacle-free field or full knowledge of the field layout is often assumed. We present new schemes that are not governed by these assumptions, and thus adapt to a wider range of application scenarios. The schemes are designed to maximize sensing coverage and also guarantee connectivity for a network with arbitrary sensor communication/sensing ranges or node densities, at the cost of a small moving distance. The schemes do not need any knowledge of the field layout, which can be irregular and have obstacles/holes of arbitrary shape. Our first scheme is an enhanced form of the traditional virtual-force-based method, which we term the Connectivity-Preserved Virtual Force (CPVF) scheme. We show that the localized communication, which is the very reason for its simplicity, results in poor coverage in certain cases. We then describe a Floor-based scheme which overcomes the difficulties of CPVF and, as a result, significantly outperforms it and other state-of-the-art approaches. Throughout the paper our conclusions are corroborated by the results from extensive simulations
An Analysis Review: Optimal Trajectory for 6-DOF-based Intelligent Controller in Biomedical Application
With technological advancements and the development of robots have begun to be utilized in numerous sectors, including industrial, agricultural, and medical. Optimizing the path planning of robot manipulators is a fundamental aspect of robot research with promising future prospects. The precise robot manipulator tracks can enhance the efficacy of a variety of robot duties, such as workshop operations, crop harvesting, and medical procedures, among others. Trajectory planning for robot manipulators is one of the fundamental robot technologies, and manipulator trajectory accuracy can be enhanced by the design of their controllers. However, the majority of controllers devised up to this point were incapable of effectively resolving the nonlinearity and uncertainty issues of high-degree freedom manipulators in order to overcome these issues and enhance the track performance of high-degree freedom manipulators. Developing practical path-planning algorithms to efficiently complete robot functions in autonomous robotics is critical. In addition, designing a collision-free path in conjunction with the physical limitations of the robot is a very challenging challenge due to the complex environment surrounding the dynamics and kinetics of robots with different degrees of freedom (DoF) and/or multiple arms. The advantages and disadvantages of current robot motion planning methods, incompleteness, scalability, safety, stability, smoothness, accuracy, optimization, and efficiency are examined in this paper
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