Session: 07-15-01: Dynamics and Control of Soft Structures

Paper Number: 144691

144691 - Robust Design of Dynamic Control System in Compliant Terrestrial Origami-Robots 

The objective of this paper is to introduce methodologies for designing terrestrial origami robots with robust dynamic control systems based on combinations of active and passive flexible elements acting with multiple degrees of freedom. The flat-packed robot has smart material layers for robot morphing from sheets and locomotion without bulky power sources or accessary systems. The research team used a self-folding robot driven by multi-legged systems using the ceramic smart material have a high driving force and large moving distance. Given the ability to create high-energy density, resilient, large (relatively) range-of-motion origami-robotic appendages, this research targets the design of walking robot platforms to provide desirable dynamic motions on highly uncertain terrain.

The paper demonstrates analysis techniques from the fields of robust and optimal control to attempt to reduce sensitivity of desired robot movements to ground interactions and other disturbances occurring at uncertain location and with uncertain amplitudes, as well as some sources of uncertainty associated with environmental variation and limited fabrication precision. Sources of uncertainty to be handled in robust design include variation in spring dimensions due to fabrication tolerances, variation in damping coefficients from nominal values with environmental variation, and, especially, variation in the location and behavior of contact forces at robot feet.

To increase agility of origami, we used integrated sensing mechanisms to estimate motions. This paper also demonstrates novel robot architectures and novel control mechanisms, including some new internal perception abilities for terrestrial origami-robots. The robots are based on polymer flexural mechanisms driven by high-work-density thin-film materials. The basic conceptual model of walking origami-robots based on PZT actuators and compliant elastic bending joints was visualized as a chain of rigid bodies and spring elements. The rigid bodies represent larger copper elements (body, legs) and the spring elements represent locations where motion occur, including both thin PVC beams and the driving thin-film PZT actuators. Design parameters available for optimization in this style of origami-robot design include spring dimensions, relative placement and orientations of springs and links, and intended locations of ground interaction. Known constants include inertias, taken to be determined by some top-level robot dimension and payload constraints, and nominal linear damping. Magnitudes of damping was determined experimentally for flexible devices. Careful origami-robot design both increased walking or running speed and improved robot efficiency, which are important needs given very limited power availability at the target origami-robot scale.

The devices are generally applicable in various hard-to-reach regions in space and will enable agile operations for unpredictable environments in space. Furthermore, the research could also complement various applications in expanding the use of soft (non-rigid) structures.

Presenting Author: Trevor Harms Northern Kentucky University

Presenting Author Biography: The author, Trevor Harms is from Fort Thomas, Kentucky and graduated from
Highlands High School in 2021. He is currently working towards my Bachelors in Mechatronics
Engineering Technology at Northern Kentucky University. My area of focus is automated
manufacturing with minors in industrial and electrical technology. I am on track to graduate
spring of 2025.

Authors:

Trevor Harms Northern Kentucky University
Minchul Shin Northern Kentucky University