A Parallelogram-Based Parallel Manipulator for Schönflies Motion

Abstract

A parallelogram-based 4 degrees-of-freedom parallel manipulator is presented in this paper. The manipulator can generate the so-called Schönflies motion that allows the end effector to translate in all directions and rotate around an axis parallel to a fixed direction. The theory of group of displacements is applied in the synthesis of this manipulator, which employs parallelograms in every limb. The planar parallelogram kinematic chain provides a high rotational capability and an improved stiffness to the manipulator. This paper shows the kinematic analysis of the manipulator, including the closed-form resolution of the forward and inverse position problems, the velocity, and the singularity analysis. Finally, a prototype of the manipulator, adding some considerations about its singularity-free design, and some technical applications in which the manipulator can be used are presented.

Circular motion analysis for a novel 4-DOF parallel kinematic machine

“…However, to the authors' knowledge, all existing 4-DOF parallel mechanisms either have a rotational degree of freedom around the vertical axis or two rotational DOF, which are suitable for pick and place and positioning tasks. Oscar Salgado et al [16] presented a parallel manipulator performing Schoenflies motion with rotational capability around an axis parallel to a fixed direction. They indicated that their mechanism can perform operations such as drilling or riveting.…”

Type Synthesis of Kinematically Redundant 3T1R Parallel Manipulators

“…During the past decade, great advances have been made on the type synthesis of parallel mechanisms (PMs). In addition to a large number of PMs (see [1][2][3][4][5][6][7][8] for example), several systematic approaches have been proposed for the type synthesis of PMs, such as the method based on the displacement group [2,[9][10][11][12][13][14][15], the method based on screw theory [16][17][18][19], the single-openedchain approach [20], the virtual-chain approach [21,22], the linear transformation approach [23] and other approaches such as [24].…”

Quantitative Performance Analysis of Haptic Devices With Parallelogram Subsystems

“…Furthermore, there is interest in constructing devices with additional closed kinematic-loop (e.g. planar parallelogram subsystem) to improve the overall stiffness, remove singularity and permitting relocation of the actuation [2][3][4]. Many commercial serial-and parallel-type haptic devices, shown in Figure 1, now incorporate such parallelogram linkages.…”