Posters

Shape-morphing devices, a crucial branch in soft robotics, hold significant application value in areas like human machine interfaces, biomimetic robotics, and tools for interacting with biological systems. To replicate arbitrary shapes, an array of soft actuators is required, with each actuator being individually controllable. Due to the
significant coupling between the actuators in the array, we seek machine learning approaches to control their deformation, while also exploring under-actuation strategies for more efficient control of a large array of actuators.

This poster presents the research conducted at Purdue's RAAD Lab on Serial Pneumatic Artificial Muscles (sPAMs) designed for soft robotic applications. These actuators, made from thin, inelastic membranes, exploit the geometrical effects on actuator behavior to enhance the kinematic shaping of soft robots. Our improved modeling approaches allow for the design of variable-constraint actuators with enhanced programmability and adaptability. By incorporating linear-elastic constraints with variable end constrictions responsive to input pressures, the actuators can transition between contraction and expansion, effectively managing force and strain. The study validates these concepts through experimental setups involving serial actuators constrained by silicone elastomer rings, demonstrating significant advancements in soft actuator design and function.

Programmable magnetic soft machines that achieve fast, reversible, and complex morphing, making them adaptable to diverse environments and functions. The use of pre-magnetized microgels enables versatile 3D magnetization profiles. However, current microgel bonding faces adhesion, biocompatibility, and self-healing challenges. The proposed approach employs N-hydroxysuccinimide ester-activated sodium alginate (SA-NHS) and chitosan (CS) for covalent bonding, creating durable interfaces. Magnetic properties and patterning are achieved by incorporating poly(ethylene glycol) diacrylate and magnetic particles into SA-NHS or CS, yielding modularized microgels. Several applications are showcased, including 2D and 3D programmable magnetic shape-morphing machines, electrode circuits, enhancing the adaptability of soft machines with intricate architectures.

The TorsioSquid is a bio-inspired robotic system designed to emulate the unique propulsion mechanism of squids through a novel design that uses softer, more flexible components such as bowden cables and torsional buckling to overcome the limitations of traditional rigid mechanisms. Central to its design is a linear actuator within a helically wrapped shell, which manipulates the shell to mimic the squids' mantle movements, effectively generating thrust for propulsion. We utilized Ansys simulations to refine the design, achieving a significant mass ejection rate of 0.4 kg/sec, which enhances thrust for efficient underwater propulsion. This innovative design makes TorsioSquid particularly suited for tasks such as underwater exploration and surveillance, promising advancements in soft robotic applications in marine environments.

Miniature robots provide unprecedented access to confined environments and show promising potential for novel applications such as search-and-rescue and high-value asset inspection. Current robots (especially at the insect scale) cannot modify their shape to significantly improve performance or add new functionality. Insects demonstrate additional skills through exoskeletal body compliance, enabling locomotion through environments smaller than body size. Yet, the change in scale, and use of exoskeletal shape morphing enables observation of nature with a new perspective. We have developed robots out of individual leg modules contain actuators and sensing. The modular robot structure has passive inter-segment flexures for body compliance. Spherical five-bar linkages are used for leg joint mechanics, with optimized actuation for additional payload. Each leg tip has two independent degrees of freedom. Sensing is incorporated into the joints and actuators. The exoskeleton shape morphing design of our robot has demonstrated omnidirectional locomotion in variety of environments and running on a variety of different surfaces. Passive body shape-morphing enabled Eclair to maneuver through a lateral constraint, narrower than the neutral body shape. The use of design concepts from exoskeletal interlinked modular robot units enable passive body compliance in insect scale robots to locomote in confined terrain previously not accessible.

TBD