Structure Design And Reliability Analysis Of The Bionic Lower Extremity Exoskeleton Robot

As a popular research object of wearable devices currently, bionic lower extremity exoskeleton robot is a kind of man-machine integration system which can make person walking for long distance in the loading conditions. It provides additional power to the body through the simulation of human lower limb skeletal structure, joint rotation and muscle movement so as to give the lower extremity of the wearer to support, protection and assistance effect.The lower extremity exoskeleton anthropomorphic is the main problem of the device design because it is the human body wearable device, while the lower extremity exoskeleton in practical application due to the movement of the mechanism of uncertainties, which influence the wearer’s safety and comfort, so the reliability analysis of motion accuracy of the device is the problem of reliability analysis after the device design. This paper focuses on these two problems by the analysis of three aspects which are the analysis of the lower limb of the human body structure, the personification of the lower extremity exoskeleton modeling design optimization and the reliability analysis by mechanism reliability theories of movement precision. The main contents of this paper are:(1) The CAD model of human body is established by SolidWorks through the related parameter of human lower extremity of each body segment analysis. Dynamics simulation of the model is carried out through the use of ADAMS to obtain the joint torque of lower limb of the human body so as to provide reference data for the selection of driver of exoskeleton. Meanwhile, analysis and modeling of kinematics of human lower extremity and verify the correctness of the mathematical model provide the theoretical foundation for reliability analysis of kinematic accuracy of lower extremity exoskeleton.(2) The preliminary design method of mechanism is formed by analyzing the principle of lower limb exoskeleton robot and related parameters on the human lower limb. In order to reduce the energy consumption of the lower extremity exoskeleton, the simplified model of exoskeleton is optimized by the genetic algorithm theory. The physical model of optimal data is established based on the lower extremity exoskeleton to calculate the hydraulic cylinder stroke data and complete the selection of hydraulic cylinder by using the stroke data and lower limb joint torque.(3) By referring the movement accuracy of the mechanism reliability theory, this paper summarizes the mechanism motion reliability analysis method of instantaneous and time-dependent reliability theory. In the case of time-dependent, Monte Carlo simulation theory is applied to the lower extremity exoskeleton movement variable precision in reliability analysis, and Simulink tools are used for modeling and simulation to calculate the time-dependent reliability in combination with the joint angle of human error on the random road.In this paper, the lower extremity exoskeleton is researched by the analysis and design of its structure and the optimization design of its size and the analysis of the motion precision reliability in order to obtain a conventional design method. A motion precision reliability of uncertainty analysis method is advanced under conditions of uncertainty. The purpose of this paper is providing a theoretical basis and technical support for the practical engineering of the lower extremity exoskeleton.