Cable-suspended robotic contour crafting system: Fid-Bau Portal

Cable-suspended robotic contour crafting system

Bosscher, Paul / Williams II, Robert L. / Bryson, Sebastian / Castro-Lacouture, Daniel

This paper has presented a new cable robot, the C⁴ robot, designed for use in a contour crafting system. It combines several novel features, including a geometry that permits easy translation - only motion and highly simplified kinematic equations, and the use of actuated cable mounts that allow online reconfiguration of the cable robot to eliminate cable interference while maintaining full constraint of the end- effector. This system provides the ability to contour craft large structures while still being less expensive and more portable than current concepts for contour crafting systems. The forward and inverse position kinematics solutions were discussed, which incorporated the concept of virtual cables in order to simplify the forward position kinematics. The static equations were presented, including a discussion of how the redundancy of the manipulator can be used to maintain non-negative tensions in all cables. Lastly, the manipulator's workspace was investigated for an example geometry, including calculation of the maximum cable tension for a variety of loading conditions. The workspace was determined to be very large, with low maximum cable tensions for nearly all positions. Based on this workspace analysis, it was concluded that the frame of the robot only needs to be slightly larger than the building being constructed. Future plans for manipulator development include constructing a scale prototype (with a l m cube frame), detailed mechanical design of the system components, and development of calibration routines. Additional work is also underway on improved construction materials and extrusion/troweling tooling.