Abstract: Hydraulic actuator is the core actuator of high-end mobile equipment such as aerospace, robot and engineering machinery, and it is the "muscle" of hydraulic system. In order to improve the endurance, mobility and carrying capacity of the high-end mobile equipment, the lightweight design of the hydraulic actuator is one of the main solutions. The hydraulic actuator which is suitable for the key drive of the leg of the legged robot is taken as the research object. Firstly, the accurate mass model of each part of the actuator is established. Then, the global sensitivity analysis method based on Sobol, which can quantitatively evaluate the influence of parameters on the model, is adopted. Combined with Monte Carlo numerical simulation method, the analysis efficiency is enhanced, and the influence law of mass parameters on the quality of the actuator is revealed. Finally, the key parameters affecting the quality of the hydraulic actuator are obtained. The accuracy of sensitivity analysis results is verified by system modeling. At the same time, the analysis method used is a general method, which can be used for mass modeling and sensitivity analysis of different hydraulic actuators, and provide an important theoretical reference for lightweight design.

Key words: hydraulic actuator, lightweight, legged robot, quality modeling, global sensitivity analysis