The Effects of Manufacturing Parameters on Static Characteristics of Water Hydraulic Artificial Muscles

The static characteristics of water hydraulic artificial muscles (WHAMs) are related to operating parameters and manufacturing parameters. Operating parameters include working pressure and contraction ratio. Manufacturing parameters include initial braiding angle, fiber sleeve material, and initial rubber tube thickness. These manufacturing parameters fundamentally influence the static characteristics of artificial muscle. Orthogonal experiments were designed with an initial braiding angle of 25 degrees and 32 degrees, fiber sleeve of UHMWPE and aramid 1414, and initial rubber tube thickness of 2mm and 3mm to study the significance level of the effects of these factors and their interactions on the static characteristics of WHAMs. Experiments were carried out at different contractions to study the relationship between contraction force and working pressure, and Analysis of Variance (ANOVA) analyzed the test data. The analysis results showed that the significance level of the initial braid angle on WHAM's static characteristics is the most significant; the significance level of fiber sleeve material and initial rubber tube thickness on the static characteristics of WHAMs depends on the working pressure and contractions. The analysis results help people fabricate different WHAM types according to the working conditions, which help people better control the contraction forces.