26,402 research outputs found
Multi-Segment Parallel Continuum Manipulator
Continuum manipulators are a type of robot arm that resemble biological tentacles and trunks. They have a flexible and compliant structure, which may allow them to out-perform rigid-link designs in cluttered workspaces or in environments that contain people. While most continuum manipulators are required to have constant curvature along the length of each segment, a new design known as a parallel continuum manipulator removes this restriction and inherits some properties of parallel rigid-link robots such as greater stability, precision, strength, and maneuverability. Until now, only single segment forms of these manipulators have been created. This project expands this manipulator design concept by creating the first multi-segment parallel continuum manipulator
Regrasp Planning using 10,000s of Grasps
This paper develops intelligent algorithms for robots to reorient objects.
Given the initial and goal poses of an object, the proposed algorithms plan a
sequence of robot poses and grasp configurations that reorient the object from
its initial pose to the goal. While the topic has been studied extensively in
previous work, this paper makes important improvements in grasp planning by
using over-segmented meshes, in data storage by using relational database, and
in regrasp planning by mixing real-world roadmaps. The improvements enable
robots to do robust regrasp planning using 10,000s of grasps and their
relationships in interactive time. The proposed algorithms are validated using
various objects and robots
A Certified-Complete Bimanual Manipulation Planner
Planning motions for two robot arms to move an object collaboratively is a
difficult problem, mainly because of the closed-chain constraint, which arises
whenever two robot hands simultaneously grasp a single rigid object. In this
paper, we propose a manipulation planning algorithm to bring an object from an
initial stable placement (position and orientation of the object on the support
surface) towards a goal stable placement. The key specificity of our algorithm
is that it is certified-complete: for a given object and a given environment,
we provide a certificate that the algorithm will find a solution to any
bimanual manipulation query in that environment whenever one exists. Moreover,
the certificate is constructive: at run-time, it can be used to quickly find a
solution to a given query. The algorithm is tested in software and hardware on
a number of large pieces of furniture.Comment: 12 pages, 7 figures, 1 tabl
A new meta-module for efficient reconfiguration of hinged-units modular robots
We present a robust and compact meta-module for edge-hinged modular robot units such as M-TRAN,
SuperBot, SMORES, UBot, PolyBot and CKBot, as well as for central-point-hinged ones such as Molecubes and
Roombots. Thanks to the rotational degrees of freedom of these units, the novel meta-module is able to expand
and contract, as to double/halve its length in each dimension. Moreover, for a large class of edge-hinged robots the
proposed meta-module also performs the scrunch/relax and transfer operations required by any tunneling-based
reconfiguration strategy, such as those designed for Crystalline and Telecube robots. These results make it possible to
apply efficient geometric reconfiguration algorithms to this type of robots. We prove the size of this new meta-module to
be optimal. Its robustness and performance substantially improve over previous results.Peer ReviewedPostprint (author's final draft
A Bio-Inspired Tensegrity Manipulator with Multi-DOF, Structurally Compliant Joints
Most traditional robotic mechanisms feature inelastic joints that are unable
to robustly handle large deformations and off-axis moments. As a result, the
applied loads are transferred rigidly throughout the entire structure. The
disadvantage of this approach is that the exerted leverage is magnified at each
subsequent joint possibly damaging the mechanism. In this paper, we present two
lightweight, elastic, bio-inspired tensegrity robotics arms which mitigate this
danger while improving their mechanism's functionality. Our solutions feature
modular tensegrity structures that function similarly to the human elbow and
the human shoulder when connected. Like their biological counterparts, the
proposed robotic joints are flexible and comply with unanticipated forces. Both
proposed structures have multiple passive degrees of freedom and four active
degrees of freedom (two from the shoulder and two from the elbow). The
structural advantages demonstrated by the joints in these manipulators
illustrate a solution to the fundamental issue of elegantly handling off-axis
compliance.Comment: IROS 201
Optimal dimensional synthesis of force feedback lower arm exoskeletons
This paper presents multi-criteria design optimization of parallel mechanism based force feedback exoskeletons for human forearm and wrist. The optimized devices are aimed to be employed as a high fidelity haptic interfaces. Multiple design objectives are discussed and classified for the devices and the optimization problem to study the trade-offs between these criteria is formulated. Dimensional syntheses are performed for optimal global kinematic and dynamic performance, utilizing a Pareto front based framework, for two spherical parallel mechanisms that satisfy the ergonomic necessities of a human forearm and wrist. Two optimized mechanisms are compared and discussed in the light of multiple design criteria. Finally, kinematic structure and dimensions of an optimal exoskeleton are decided
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