We describe fundamental research in the modeling and design of novel long, continuous backbone “hose” robots. These trunk and tentacle “continuum” robots actively modify the bending along their compliant backbones. This feature allows them to both enter into, and maneuver and operate within, tight spaces in which neither conventional rigid-link robots nor people can access. We discuss continuum robotic hoses, in which tendons are routed through specially designed collars routed along the exterior of industrial hoses, and which are terminated in groups at predetermined locations along the hose. The tendons are remotely actuated by motors located at the base of the hose. This creates a series of two degree of freedom sections along the hose, with the section endings corresponding to the locations of tendon set terminations. When deployed as active hoses, these robots can enable novel applications in 3D printing and cement pouring. However, delivering cementious materials through a hose along the length of a continuum robot adds significant mass that must be supported, in addition to novel inertial effects that need to be compensated for. We report on modeling to enable design optimization of such cable robots. Previous design and modeling of continuum robots has concentrated on medical applications, in which the scale of the robot is small (considerably less than 1 meter), and the robot structure is largely supported by the environment (tubes within the body). While models exist that relate tendon tensions to a continuum robot’s configuration, no models consider the effects of gravity on these tendon tensions. Modeling tendon tensions for active hose applications of continuum robots is necessary for sizing motors, tendons, and other components to ensure that the robot can safely support its mass during operation. In this paper, we discuss the addition of gravity to a static model developed for low-mass tendon-actuated continuum robots. Using the same Euler-Lagrange methodology as in previously reported models, the potential energy due to gravity is incorporated into the formulation of the equations that describe tendon tensions as a function of the robot’s configuration. The model is supported by experimental results that simulate a distributed load along a continuum robot using multiple point masses. Preliminary results reveal that the tendon tensions of a continuum robot are better described by the model with gravity than without gravity. We discuss the application of the models for optimizing the design and sizing of cable-driven continuum robots for applications where a large scale (multi-meter) continuum robot must support a significant, distributed and dynamic mass such as in 3D cement printing applications.


Modeling and Design Optimization of Robotic Hoses for 3D Printing of Cement

Division / Sponsors: 
Aerospace, Bioengineering, Applied Mechanics, Design Engineering Division, Advanced Energy Systems, Manufacturing Engineering Division, Noise Control and Acoustics, Nondestructive Evaluation, Diagnosis, and Prognosis (NDPD), Nuclear Engineering Division, Process Industries Division, Fluids Engineering, Heat Transfer, Materials, Microelectromechanical Systems, Safety Engineering and Risk Analysis, Computers & Information in Engineering


Paper Proceedings: https://asmedigitalcollection.asme.org/IMECE/IMECE2020/volume/84478

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