Structure Design and Kinematics Analysis of a Novel Unpowered Load-Carrying Lower Extremity Exoskeleton with Parallel Topology

A novel unpowered load-carrying parallel lower extremity exoskeleton is proposed. It is aimed at enhancing the load-bearing ability of the operator. Firstly, the structure of the novel exoskeleton is depicted in the second section; meanwhile, the degree of freedom concerning the exoskeleton is gotten by analyzing the number of links and the kinematic joints. Secondly, the forward position analysis of the exoskeleton for the swing leg is obtained. Using the expressions concerning the joints of knee and angle, the workspace of the swing leg in supporting gait circle is analyzed by the software of MATLAB. Thirdly, according to the schematic diagram of the mechanism, the static force analysis of the supporting leg for the exoskeleton is obtained. Finally, the static force of the supporting leg of the person who is not wearing the unpowered exoskeleton is gotten. Meanwhile, the genetic algorithm is used to get the optimum stiffness of the spring for energy-restoring device. By comparing the changes of force and torque for the supporting leg who is not wearing it and the skeleton which is worn by a person, some conclusions are carried out.