Design and Validation of New Methodology for Hydraulic Passage Integration in Carbon Composite Mechanisms

Humanoid robots have rapidly become the focus of research in recent years, with the most impressive humanoids being hydraulically actuated. This is due to the capacity of hydraulic actuation to provide simultaneous high forces with dynamic motion. The scarcity of hydraulic robots is mainly due to the difficulty in managing hydraulic pipes. These decrease the robot’s social acceptance and safety and are the main source of leaks. Recently, there has been a new trend in hydraulically actuated robots that involves creating internal oil passages within the robotic parts to eliminate the need for external flexible tubes. Developing these parts using carbon composite materials provides an additional advantage of ensuring lightweight yet robust robotic parts. However, assembling hydraulically integrated parts is challenging due to the leakproof requirement and the high pressures involved. This article proposes a new, reliable, and effective method that ensures a strong, leakproof assembly. A mathematical model with 11 parameters describing the assembly zone and accounting for geometric parameters, material characteristic parameters, and porosity has been developed. A numerical model was conducted to evaluate the effect of these parameters on the state of the assembly. Experimental validation was conducted to evaluate the assembly force. A satisfactory convergence between the mathematical model and the experimental results was observed with a maximum deviation of 20%.