Parameters Optimization of a Novel 5-DOF Gasbag Polishing Machine Tool

The research on the parameters optimization for gasbag polishing machine tools, mainly aims at a better kinematics performance and a design scheme. Serial structural arm is mostly employed in gasbag polishing machine tools at present, but it is disadvantaged by its complexity, big inertia, and so on. In the multi-objective parameters optimization, it is very difficult to select good parameters to achieve excellent performance of the mechanism. In this paper, a statistics parameters optimization method based on index atlases is presented for a novel 5-DOF gasbag polishing machine tool. In the position analyses, the structure and workspace for a novel 5-DOF gasbag polishing machine tool is developed, where the gasbag polishing machine tool is advantaged by its simple structure, lower inertia and bigger workspace. In the kinematics analyses, several kinematics performance evaluation indices of the machine tool are proposed and discussed, and the global kinematics performance evaluation atlases are given. In the parameters optimization process, considering the assembly technique, a design scheme of the 5-DOF gasbag polishing machine tool is given to own better kinematics performance based on the proposed statistics parameters optimization method, and the global linear isotropic performance index is 0.5, the global rotational isotropic performance index is 0.5, the global linear velocity transmission performance index is 1.012 3 m/s in the case of unit input matrix, the global rotational velocity transmission performance index is 0.102 7 rad/s in the case of unit input matrix, and the workspace volume is 1. The proposed research provides the basis for applications of the novel 5-DOF gasbag polishing machine tool, which can be applied to the modern industrial fields requiring machines with lower inertia, better kinematics transmission performance and better technological efficiency.

Kinematics of whip spider pedipalps: a 3D comparative morpho-functional approach

Amblypygi are tropical and subtropical ambush predators that use elongated,raptorial pedipalps for different activities.Although pedipalp use in predation and courtship has been explored in videography in vivo analyses,kinematic ex vivo examination of these appendages has not been conducted.Here,we rectify this lack of data by using microCT scans to 3D-kinematically model the appendage morphology and the range of motion(ROM)of the joints for Damon medius and Heterophrynus elaphus.We illustrate the successful application of this technique to terrestrial euarthropods in determining the maximum ROM values for each pedipalp joint.We also note that,in life,these values would be lower due to motion restricting structures like tendons,arthrodial membranes,and muscles.We further compare our maximum values obtained here with data from video-based motion analyses.The ROM of each joint shows the greatest flexibility in the femur-tibia joint(140–150°),the lowest in the basitarsus-claw joint(35–40°).ROM in the tibia-basitarsus joint is markedly distinct(D.medius:44°;H.elaphus:105°).This disparity reflects how H.elaphus uses the joint in the capture basket,while D.medius uses the femur-tibia joint to form the capture basket.We further illustrate notable vertical motion of the H.elaphus pedipalp compared to D.medius.This difference reflects the retro-ventral trochanter apophysis of H.elaphus.Our study opens the possibility to further whip spider kinematic understanding.Examination of other taxa using this approach will result in a more comprehensive understanding of the ecological significance and ethological implications of this unique arachnid group.