Development of manufacturing technique for composite structures for robotic applications

Abstract

An experimental study was performed with the aim of developing a technique for manufacturing composite parts for use in dynamic robotic applications in lieu of heavy and expensive metal parts used in conventional robotic systems. There is already a wide usage of sandwich board materials in load bearing applications, but these do not provide equal strength in all directions, particularly compressive strength. Additionally, these materials are only available in two-dimensional shapes. The process developed over the course of this project seeks to make a fully covered composite of any desired geometries. The specific robotics project addressed was the hyper dynamic quadruped robotic platform, which ultimately seeks to design and construct a robot capable of a high speed gallop. This thesis began exploring methods of fabricating parts for one of the legs of the platform, specifically a radius part. Manufactured components needed to be both light in weight to facilitate ease of movement for the robot and strong enough to withstand the forces from the shifting weight during running. Proposed design parameters called for a foam core with a hard plastic shell to meet these needs. This technique can lead to a cheaper manufacturing method with a potential impact on the future robotics industry. After an investigation into the properties of different liquid polyurethane foams and plastics, the manufacturing techniques explored began with machining molds for both the inner core and outer shell of composite parts into wax blocks. The project aims were to develop a prototyping process, but this can lead to mass-production. Two versions of a manufacturing process with these blocks were developed, one which uses an open mold and one which uses a closed mold. Either method is viable for fabrication, with a preference for the open mold in parts with simple geometry and small thickness, and for the closed mold in larger parts or ones with complicated or interrupted outer perimeters.