A decoupled mechanism based on intersecting planes that can be considered as a parallel mechanism with two arms is presented in this paper. The end-effector is connected to the base through two planar serial arms. The new specific characteristics of novel mechanism allow the generation of a remote center of motion (RCM) possessing two decoupled rotational degrees-of-freedom (DoF) and a tanslational DoF. It has a simpler control scheme and a larger workspace due to the decoupling characteristics of this mechanism when compared with the RCM mechanism based on intersecting planes proposed by Li et al. This mechanism also eliminates the singularity inside its workspace that impairs the original mechanism. In the final part of this paper, through an analysis of the force transmission performance, we derive a method to adjust the length of the linkage to optimize its force transmission performance.
A model framework for the prediction of defects in strip steel is proposed with the objective of enhancing the accuracy of defect detection. Initially, the data are balanced through the utilisation of the Improved Synthetic Minority Oversampling Technique (ISmote), which is based on clustering techniques. Subsequently, further enhancements are made to the inertia weights and learning factors of the immune particle swarm optimisation (IPSO), with additional optimisations in speed updates and population diversity. These enhancements are designed to address the issue of premature convergence at the early stages of the process and local optima at the later stages. Finally, a prediction model is then constructed based on stacking, with its hyperparameters optimised through the improved immune particle swarm optimisation (IIPSO). The results of the experimental trials demonstrate that the IIPSO-ISmote-Stacking model framework exhibits superior prediction performance when compared to other models. The Macro_Precision, Macro_Recall, and Macro_F1 values for this framework are 93.3%, 93.6%, and 92.2%, respectively.
7 September 2019 in Mechanisms and Machine Science
Rigid foldability is a special property of rigid origami patterns, where each origami plane remains undeformed during continuous movement along the predetermined crease. Current research on the rigid foldability of origami patterns mainly focuses on kinematics, while less attention is paid to factors that cause deformation of the folding plane. Whether the relative spatial position of adjacent creases has been changed is a critical factor that influences the state (rigid or deformed) of the folding plane between the two adjacent creases during the folding process. This study considered two factors (linear relationship and Euclidean distance) to measure the changes in the spatial positions of creases, explored the relationship between the two factors and rigid folding, and identified deformation forms that affect rigid foldability. First, the origami pattern was regarded as a linkage mechanism, and the linear relationship between creases was determined from the single-vertex origami unit forming this origami structure. Then, the geometric parameters of the origami pattern were used to calculate the Euclidean distance between two points on adjacent creases during the folding process. If the linear relationship and Euclidean distance always remain the same, the origami pattern has rigid foldability. Based on changes in the Euclidean distance, this method can also help determine the main deformation of non-rigidly foldable origami patterns. In addition, it can be applied to origami patterns with four or five vertices and multiple loops, and it further provides a novel approach for determining the layout of the crease position and the judgment of rigid foldability during origami-inspired mechanism design.