It has been perceived that the reconfigurable mechanism has gradually evolved attractive paradigms for studying the mechanism and machine science towards an overwhelming new direction. More and more studies have been put forward during the past decade, leading to numerous fruitful efforts to this new research field. While the studies about the reconfigurable mechanisms were obviously increased, manifold, and diverse, there should be a good discussion about reconfigurable mechanisms to steer the relevant works towards the rational directions. This paper is, therefore, organized in a logical way to provide a test stone for the relative studies, especially for those in the filed of mechanism and machine science, on reconfigurable mechanisms. The paper provides identification of topology and configuration of mechanisms and gives the theoretical principles and practical strategies for changing the topology and/or configuration of mechanisms. It is expected that based on this result more studies for the reconfigurable mechanisms can be motivated in the future.

Reconfiguration Principles and Strategies for Reconfigurable Mechanisms

The study provides a solution to a dimensional synthesis problem for a hexapod-type reconfigurable parallel mechanism, which can change its configuration to realize different trajectories of its output link while having a single drive. The work presents an original procedure to find the dimensions of some mechanism’s links and their initial configuration to reproduce these trajectories. After describing the mechanism, the paper examines kinematic relations representing the basis for the subsequent synthesis algorithm. Next, the obtained expressions are extended and provide a system of equations to be solved. The structure of this equation system allows it to be solved effectively by numerical methods, which is demonstrated with an example. The proposed algorithm of dimensional synthesis does not require solving the optimization problems, in contrast to the familiar methods of dimensional synthesis of parallel mechanisms. Further, the suggested approach to the synthesis problem allows finding solution in a fast and computationally efficient manner.

https://www.mdpi.com/2075-1702/9/6/117/pdf

Dimensional (Parametric) Synthesis of the Hexapod-Type Parallel Mechanism with Reconfigurable Design

Position, velocity, and workspace analysis of a novel 6-DOF parallel manipulator with “piercing” rods

Kinematics analysis and workspace optimization for a 4-DOF 3T1R parallel manipulator

This article presents the velocity and singularity analysis for a five-degree-of-freedom (5-DOF) parallel-serial manipulator. The hybrid structure of the manipulator combines a tripod-like parallel part and a serial part, represented as two carriages moving in perpendicular directions. This manipulator provides its end-effector with a 3T2R motion pattern, which includes three independent translations and two independent rotations. First, the study briefly discusses the manipulator design and the results of the position analysis. These results form the basis for the subsequent velocity and singularity analysis, performed by screw theory. The screw coordinates of the unit twists are written for each manipulator joint, and then through the reciprocal screw approach, the actuation and constraint wrenches of the manipulator are obtained by simple inspection. Based on these twists and wrenches, the paper forms the velocity equation and shows an example of the inverse velocity analysis for a given end-effector trajectory. The same example is solved by numerical differentiation to verify the proposed approach. Next, the paper investigates singular configurations by analyzing the wrench system of the manipulator and presents several conditions for serial and parallel singularities. Each condition has both a symbolic representation, given by an equation for screw coordinates of certain wrenches, and a visual representation, which shows the manipulator in a singular configuration.

/pdf/velocity-and-singularity-analysis-of-a-5-dof-3t2r-parallel-11gfs5ke.pdf

Velocity and Singularity Analysis of a 5-DOF (3T2R) Parallel-Serial (Hybrid) Manipulator

The proposed study provides a solution of the inverse and forward kinematic problems and workspace analysis for a five-degree-of-freedom parallel–serial manipulator, in which the parallel kinematic...

https://journals.sagepub.com/doi/pdf/10.1177/1729881421992963

Inverse and forward kinematics and workspace analysis of a novel 5-DOF (3T2R) parallel–serial (hybrid) manipulator:

Inverse and Forward Kinematic Analysis of a 6-DOF Parallel Manipulator Utilizing a Circular Guide

In this paper the description of the development of three-point wheel-legged robotic platform and its movement was given. The motion control problem was targeted because of sophisticated walking technique with highly different phase timings. Movement algorithm, straight kinematics problem, inverse kinematics problem and dynamics problem solving are shown for the developed 3D-model. The complete algorithm of motion control was implemented for the model. New methods of mathematical modeling and their assistance were shown for design of new robotic device. The advantages of modern technologies of fast prototyping were described based on 3D printing.

Anton Antonov

Papers

Dimensional (Parametric) Synthesis of the Hexapod-Type Parallel Mechanism with Reconfigurable Design

Position, velocity, and workspace analysis of a novel 6-DOF parallel manipulator with “piercing” rods

Inverse and forward kinematics and workspace analysis of a novel 5-DOF (3T2R) parallel–serial (hybrid) manipulator:

Inverse and Forward Kinematic Analysis of a 6-DOF Parallel Manipulator Utilizing a Circular Guide

Mathematical Model of 3-P Wheel-Legged Mobile Robotic Platform