No abstract

To improve locomotion and operation integration, this paper presents an integrated leg-arm quadruped robot (ILQR) that has a reconfigurable joint. First, the reconfigurable joint is designed and assembled at the end of the leg-arm chain. When the robot performs a task, reconfigurable configuration and mode switching can be achieved using this joint. In contrast from traditional quadruped robots, this robot can stack in a designated area to optimize the occupied volume in a nonworking state. Kinematics modeling and dynamics modeling are established to evaluate the mechanical properties for multiple modes. All working modes of the robot are classified, which can be defined as deployable mode, locomotion mode and operation mode. Based on the stability margin and mechanical modeling, switching analysis and evaluation between each mode is carried out. Finally, the prototype experimental results verify the function realization and switching stability of multimode and provide a design method to integrate and perform multimode for quadruped robots with deployable characteristics.

No abstract

A wire-driven planar curved notched flexible manipulator with variable cross-section is designed. Based on the Bernoulli Euler beam equation, the end track and rotation angle of the notched flexible manipulator with variable cross-section after applying force is deduced theoretically. In addition, the 3R pseudo rigid body model is used to calculate the end track and rotation angle, and ABAQUS finite element analysis software is used for motion simulation. Then, MATLAB is used for post-processing to obtain the end track of the flexible manipulator. By comparing the track of the 3R pseudo rigid body model with the ABAQUS simulation track, the relative error is obtained. The conclusion proves that the 3R pseudo rigid body model can effectively simulate the end track of a notched flexible manipulator with variable cross-section after bending, which expands a new method for solving the complex end motion problem of a flexible manipulator with variable cross-section, and also broadens the applicable structure of the 3R pseudo rigid body model.

Power-assisted upper-limb exoskeletons are primarily used to improve the handling efficiency and load capacity. However, kinematic mismatch between the kinematics and biological joints is a major problem in most existing exoskeletons, because it reduces the boosting effect and causes pain and long-term joint damage in humans. In this study, a shoulder augmentation exoskeleton was designed based on a parallel mechanism that solves the shoulder dislocation problem using the upper arm as a passive limb. Consequently, the human–machine synergy and wearability of the exoskeleton system were improved without increasing the volume and weight of the system. A parallel mechanism was used as the structural body of the shoulder joint exoskeleton, and its workspace, dexterity, and stiffness were analyzed. Additionally, an ergonomic model was developed using the principle of virtual work, and a case analysis was performed considering the lifting of heavy objects. The results show that the upper arm reduces the driving force requirement in coordinated motion, enhances the load capacity of the system, and achieves excellent assistance.