Virtual Prototyping for Robotic Fabrication of Rebar Cages in Manufactured Concrete Construction

Abstract

With the advent of precast construction technology, the construction industry has seen a rapid change in the way structures are built. Precast construction has reduced project costs and durations, increased the predictability, and improved the quality of construction. It has also resulted in a shift in construction tasks from the construction site to the factory floor. Precast elements are manufactured and cured in controlled factory environments and are then transported to the construction site for assembly. This shift into the factory makes the process a viable candidate for automation. However, because of the nature of the construction industry, it is important that the automation technology used be reconfigurable in a way that accommodates frequent changes in design and demand. Most precast elements currently used are made of RC. This paper considers the unique constraints inherent in precast construction and proposes a method with which to automate the production of precast concrete elements. Assembly and placement of rebar cages is an important step during the precast segment manufacturing process. An automated procedure for assembling the steel reinforcement cage for precast elements is described. This includes the placement of longitudinal reinforcement bars, followed by the placement and bending of transverse reinforcement. The entire design and analysis is conducted using virtual reality (VR)-assisted virtual prototyping to reach a favorable design for the proposed mechanism, without having to construct an actual prototype. Several simulations of the proposed mechanism were run and the kinematic design of the mechanism was evaluated. It was observed that the VR model offers a cost-effective method for the iterative design and evaluation of the mechanism. It can also be used to study and optimize joint trajectories. Future work includes developing a scaled prototype model to validate the design, followed by a full-scale prototype.