Dual-arm robotic manipulation of flexible cables

Abstract Due to the flexibility and high degrees-of-freedom of flexible cables, their dynamic modeling and precise control are challenging. In this paper, the dynamic modeling and control of flexible cables with human-like dual manipulators are studied to deploy them on a plane and form the desired shapes automatically. First, we establish a dynamic model of flexible cables based on a discrete elastic rod model. This model can simulate their stretching, bending, and twisting deformations. Then, we consider the collisions, contacts, and frictions between the flexible cables and the plane, add kinematic constraints to the model, and finally obtain an implementable dynamic solution of the model. Next, we propose dynamic control schemes including parallel dual-arm control and coordinated dual-arm control to deploy the flexible cables on a plane and form the desired shapes for dual-arm controls. Finally, experimental and simulation studies are carried out to illustrate the effectiveness of the dynamic model and the validity of the control schemes. The results show that the model can successfully demonstrate the deformations of flexible cables, and the proposed control schemes can successfully manipulate flexible cables in different tasks.

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Manipulation Planning for Large Objects through Pivoting, Tumbling, and Regrasping

Applied Sciences ◽

10.3390/app11199103 ◽

2021 ◽

Vol 11 (19) ◽

pp. 9103

Author(s):

Ang Zhang ◽

Keisuke Koyama ◽

Weiwei Wan ◽

Kensuke Harada

Keyword(s):

Object Manipulation ◽

Robotic Manipulation ◽

Limited Area ◽

Object Surface ◽

Manipulation Planning ◽

Kinematic Constraints ◽

Unstable Support ◽

End Effectors ◽

Set Of Points ◽

Dual Arm

Robotic manipulation of a bulky object is challenging due to the limited kinematics and payload of the manipulator. In this study, a robot realizes the manipulation of general-shaped bulky objects utilizing the contact with the environment. We propose a hierarchical manipulation planner that effectively combined three manipulation styles, namely, pivoting, tumbling, and regrasping. In our proposed method, we first generate a set of superimposed planar segments on the object surface to obtain an object pose in stable contact with the table, and a set of points on the object surface for the end-effectors (EEFs) of a dual-arm manipulator to stably grasp the object. Object manipulation can be realized by solving a graph, considering the kinematic constraints of pivoting and tumbling. For pivoting, we consider two supporting styles: stable support (SP) and unstable support (USP). Our proposed method manipulates large and heavy objects by selectively using the two different support styles of pivoting and tumbling according to the conditions on the table area. In addition, it can effectively avoid the limitation arising due to the arm kinematics by regrasping the object. We experimentally demonstrate that a dual-arm manipulator can move an object from the initial to goal position within a limited area on the table, avoiding obstacles placed on the table.

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