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COBEM 2023
27th International Congress of Mechanical Engineering
An Analysis of a 4-DoF Kinematically Redundant Planar Parallel Mechanism
Submission Author:
Luan Meneghini , SC
Co-Authors:
Luan Meneghini, Henrique Simas, Roberto Simoni
Presenter: Luan Meneghini
doi://10.26678/ABCM.COBEM2023.COB2023-0773
Abstract
A mobile platform and a fixed base must be connected by at least two serial kinematic chains to form a parallel manipulator. Parallel manipulators (PMs) have many benefits over serial ones, including greater load capability, stiff- ness, accuracy, dexterity, inertia, and so on. Due to the wide application of parallel manipulators in industries, simulators, force sensors, machine tools and others, there have been significant advances in recent years. However, some challenges, such as its complex mathematical models, complex control and manufacturing, are inherent in this type of architecture. The main disadvantages of parallel manipulators are the workspace singularity regions and their limited workspace. It is known that the workspace of a parallel manipulators is typically smaller than the one of a serial manipulator. Re- dundancy parallel manipulators, i.e kinematic redundancy and the actuation redundancy, can be taken into account to reduce workspace constraints, improve rotational capabilities and avoid singularities. In this paper, redundancy in par- allel manipulators is revisited focusing in different capabilities such as stiffness, singularity, control, trajectory planning, and workspace. Redundancy was used to create a novel planar 4-DoF redundant parallel manipulator with unlimited ro- tational capabilities, that was used as a case study to analysis and discussions. The parallel manipulator has a redundant leg that promotes singularity avoidance and contributes to the unlimited rotational of movable platform. The positional and differential models are developed as well as the singularities mapped by the Jacobian matrices. Also, the workspace is evaluated by means of a geometrical approach. Finally, a new proposal of a self-aligning 4-DoF PM manipulator was showed, ensuring the perfect assembly of the prototype.
Keywords
Parallel manipulator, kinematic redundancy, singularities
