Wearable Robot Arm with Consideration of Weight Reduction and Practicality

In this paper, we propose a wearable robot arm with consideration of weight and usability. Based on the features of existing wearable robot arms, we focused on the issues of weight and usability. The behavior of human hands during physical work can be divided into two phases. In the first, the shoulder and the elbow joints move before commencing the task by using the hands. In the second, the wrist joints move during the actual work. We found that these features can be applied to wearable robot arms. Consequently, we proposed hybrid actuation system (HAS) with a combination of two types of joints. In this study, HAS is implemented into the prototype wearable robot arm, assist oriented arm (AOA). To verify the validity of the proposed system, we implemented three types of robot arms (PasAct, Act, 6DOF) using simulation to compare the weight, working efficiency, and usability. Furthermore, we compared these simulation models with AOA for evaluation.

Kinematics and Singularity Analysis of a Four-Degree-of-Freedom Serial-Parallel Hybrid Manipulator

[abstFig src='/00290003/07.jpg' width='300' text='4DOF serial-parallel hybrid manipulator' ] For adapting to the complex working environments of amphibious manipulators, we proposed a serial-parallel hybrid quadruped walking manipulator. We simplified the leg mechanism of the serial-parallel hybrid manipulator as a 2UPU-UPR parallel mechanism, and then analyzed the degree of freedom (DOF) of the parallel mechanism by using the screw theory. The results show that the position of the<span class=”bold”>Y</span>direction and the pose of the<span class=”bold”>Z</span>direction are two independent variables which influence the mechanism movement. We deduced the kinematics inverse solution and the velocity Jacobian matrix of the 2UPU-UPR parallel mechanism. Based on the analysis of the Jacobian matrix, three kinds of kinematic singularities of the 2UPU-UPR parallel mechanism are identified. The results show that the 2UPU-UPR parallel mechanism doesn’t have the kinematic inverse singularity, but it has three kinds of kinematic forward singularities and two kinds of combined singularities. Finally, the variation of motorial parameters of this 2UPU-UPR parallel mechanism was discussed by a calculation example.