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The proposed study is focused on the development of a novel modification of the slider-crank mechanism, the kinematic scheme of which is organized by coupling planar and spatial (screw) kinematic chains. The structure of this mechanism provides the end-effector with a cyclic movement along a helicoidal trajectory, while all other links have planar motions. A kinematic analysis of the synthesized mechanism is discussed in this study. The motion variables of the end-effector at different pitches in the screw joints are determined analytically and numerically. Based on the mechanism’s kinematic scheme, its assembling computer-aided design (CAD) model has been created, in accordance with which a physical prototype has been built. A functional performance of the prototype is studied by comparing the displacements of its end-effector with analogical displacements of the CAD model. The question of the technological application of the developed mechanism for spring winding and various objects’ screwing has been considered in this study.

The paper presents novel models of reconfigurable parallel mechanisms (RPMs) with a single active degree-of-freedom (1-DOF). The mechanisms contain three to six identical kinematic chains, which provide three (for the tripod) to zero (for the hexapod) uncontrollable DOFs. Screw theory is applied to carry out mobility analysis and proves the existence of controllable and uncontrollable DOFs of these mechanisms. Each kinematic chain in the synthesized mechanisms consists of planar and spatial parts. Such a design provides them with reconfiguration capabilities even when the driving link is fixed. This allows reproduction of diverse output trajectories without using additional actuators. In this paper, the model of a mechanism with six kinematic chains (hexapod) has been virtually and physically prototyped. The designing and assembling algorithms are developed using the detailed computer-aided design (CAD) model, which was further used to carry out kinetostatic analysis considering complex geometry of mechanism elements and friction among all contacting surfaces of joints. The developed virtual prototype and its calculation data have been further applied to fabricate mechanism elements and assemble an actuated full-scale physical prototype for future testing.

This article presents a model of a novel 4-DOF kinematically redundant planar parallel grasping manipulator. As distinct from the traditional 4-DOF manipulator, the proposed design includes an extensible platform, which provides kinematic redundancy. This constructive feature is used for grasping. The article discusses the inverse and forward kinematics of the proposed manipulator. The inverse kinematics algorithm provides the analytical relations between the platform coordinates and the driven (controlled) coordinates. The forward kinematics algorithm allows defining different assembly modes of the manipulator. Both algorithms are demonstrated using numerical examples. The article discusses different designs of the manipulator in which its links are placed in one, two, or three layers. Based on these designs, we performed their workspace analyses.

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