Calculation of the cable-platform collision-free total orientation workspace of cable-driven parallel robots

In this paper, a method for computing the optimal actuation of reconfigurable cable-driven parallel robots is presented. By using this method, the imperfect ability in exerting torque and limited orientation workspace of these robots may be improved. In a cable-driven parallel robot with reconfigurability, the attachment points of cables on the base are adjusted with regard to the movement of the end-effector on a trajectory. In such a design the redundant degree-of-freedom of the robot is increased accordingly. For an arbitrary pose of the end-effector, a spherical zone is defined in which the called wrench-closure condition is satisfied for a prescribed range of orientation. Taking the volume of such zone into consideration the optimal configuration of the robot may be determined. This configuration is found by appropriately changing the position of the moving attachment points on the base of the robot. By repeating this computation for a number of points on a specified trajectory, appropriate actuation plans are achieved. The computed optimal actuation guarantees balance of any external wrench by tension force of cables when the end-effector moves close to its trajectory. For a case of spatial reconfigurable cable-driven parallel robot, the optimal actuation is found based on Particle Swarm Optimization and performance of the robot is compared to the one with fixed cable attachment points on base. The result shows significant improvement of the performance of reconfigurable spatial cable-driven parallel robot.

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Rotational Workspace Expansion of a Planar CDPR with a Circular End-Effector Mechanism Allowing Passive Reconfiguration

Robotics ◽

10.3390/robotics8030057 ◽

2019 ◽

Vol 8 (3) ◽

pp. 57 ◽

Cited By ~ 1

Author(s):

Marco Carpio Alemán ◽

Roque Saltaren ◽

Alejandro Rodriguez ◽

Gerardo Portilla ◽

Juan Placencia

Keyword(s):

Degrees Of Freedom ◽

Parallel Robot ◽

Parallel Robots ◽

End Effector ◽

Effector Mechanism ◽

Circular Structure ◽

Adams Software ◽

Anchor Points ◽

Orientation Workspace ◽

Three Degrees Of Freedom

Cable-Driven Parallel Robots (CDPR) operate over a large positional workspace and a relatively large orientation workspace. In the present work, the expansion of the orientation Wrench Feasible Workspace (WFW) in a planar four-cable passive reconfigurable parallel robot with three degrees of freedom was determined. To this end, we proposed a circular-geometry effector mechanism, whose structure allows automatic mobility of the two anchor points of the cables supporting the End Effector (EE). The WFW of the proposed circular structure robot was compared with that of a traditional robot with a rectangular geometry and fixed anchor points. Considering the feasible geometric and tension forces on the cables, the generated workspace volume of the robot was demonstrated in an analysis-by-intervals. The results were validated by simulating the orientation movements of the robot in ADAMS software and a real experimental test was developed for a hypothetical case. The proposed design significantly expanded the orientation workspace of the robot. The remaining limitation is the segment of the travel space in which the mobile connection points can slide. Overcoming this limitation would enable the maximum rotation of the EE.

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Maximal Singularity-Free Total Orientation Workspace of the Gough–Stewart Platform

Journal of Mechanisms and Robotics ◽

10.1115/1.3147200 ◽

2009 ◽

Vol 1 (3) ◽

Cited By ~ 9

Author(s):

Qimi Jiang ◽

Clément M. Gosselin

Keyword(s):

Parallel Robot ◽

Stewart Platform ◽

Parallel Robots ◽

Maximal Singularity ◽

Orientation Workspace

The maximal singularity-free total orientation workspace is highly desirable in a context of design of parallel robots. In practice, this type of workspace is interesting because a parallel robot often works in a given range of orientations. In this work, an algorithm is presented to compute the maximal singularity-free total orientation workspace of the Gough–Stewart platform. In order to demonstrate the presented algorithm, an example is provided.

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On the Full-Spin Dexterous Orientation Workspace of Spherical Parallel Robots of 3-RRR-Type

EuCoMeS 2018 - Mechanisms and Machine Science ◽

10.1007/978-3-319-98020-1_41 ◽

2018 ◽

pp. 347-354

Author(s):

Khaled A. Arrouk ◽

B. Chedli Bouzgarrou ◽

Grigore Gogu

Keyword(s):

Parallel Robots ◽

Orientation Workspace

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A Cable-Driven Parallel Robot With Full-Circle End-Effector Rotations

Volume 10: 44th Mechanisms and Robotics Conference (MR) ◽

10.1115/detc2020-22426 ◽

2020 ◽

Author(s):

Marceau Métillon ◽

Saman Lessanibahri ◽

Philippe Cardou ◽

Kévin Subrin ◽

Stéphane Caro

Keyword(s):

Degrees Of Freedom ◽

Parallel Robot ◽

Parallel Robots ◽

Rigid Base ◽

Six Degrees Of Freedom ◽

Spherical Wrist ◽

In Series ◽

Dynamic Performances ◽

Moving Platform ◽

Orientation Workspace

Abstract Cable-Driven Parallel Robots (CDPRs) offer high payload capacities, large translational workspace and high dynamic performances. The rigid base frame of the CDPR is connected in parallel to the moving platform using cables. However, their orientation workspace is usually limited due to cable/cable and cable/moving platform collisions. This paper deals with the designing, modelling and prototyping of a hybrid robot. This robot, which is composed of a CDPR mounted in series with a Parallel Spherical Wrist (PSW), has both a large translational workspace and an unlimited orientation workspace. It should be noted that the six degrees of freedom (DOFs) motions of the moving platform of the CDPR, namely, the base of the PSW, and the three-DOFs motion of the PSW are actuated by means of eight actuators fixed to the base. As a consequence, the overall system is underactuated and its total mass and inertia in motion is reduced.

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A Cable-Driven Parallel Robot with Full-Circle End-Effector Rotations

Journal of Mechanisms and Robotics ◽

10.1115/1.4049631 ◽

2021 ◽

pp. 1-11 ◽

Cited By ~ 1

Author(s):

Marceau Metillon ◽

Philippe Cardou ◽

Kevin Subrin ◽

Camilo Charron ◽

Stéphane Caro

Keyword(s):

Degrees Of Freedom ◽

Parallel Robot ◽

Parallel Robots ◽

Rigid Base ◽

Six Degrees Of Freedom ◽

Spherical Wrist ◽

In Series ◽

Dynamic Performances ◽

Moving Platform ◽

Orientation Workspace

Abstract Cable-Driven Parallel Robots (CDPRs) offer high payload capacities, large translational workspace and high dynamic performances. The rigid base frame of the CDPR is connected in parallel to the moving platform using cables. However, their orientation workspace is usually limited due to cable/cable and cable/moving platform collisions. This paper deals with the design, modelling and prototyping of a hybrid robot. This robot, which is composed of a CDPR mounted in series with a Parallel Spherical Wrist (PSW), has both a large translational workspace and an unlimited orientation workspace. It should be noted that the six degrees of freedom (DOF) motions of the moving platform of the CDPR, namely, the base of the PSW, and the three-DOF motion of the PSW are actuated by means of eight actuators fixed to the base. As a consequence, the overall system is underactuated and its total mass and inertia in motion is reduced.

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