Stretchable Electroadhesion for Soft Robots

With the ongoing rise of soft robots there emerges a need for new soft robotic technologies that can cope with hyper-flexibility and stretchability. In this paper, we describe our developments on enabling controllable adhesion, namely electroadhesion, for the use in soft robots. We present a method to manufacture stretchable electroadhesive pads and characterize their performance when stretching the pad more than double its original length. Our results suggest that the normal detachment force per area slightly decreases with the stretching, while the shear detachment force per area increase with the stretch ratio. These results imply that stretchable electroadhesive pads have higher adaptivity to a given task compared to non-stretchable pads, because the stretchable pads are adaptable in terms of their mechanical stiffness as well as their adhesive force

Soft Cells for Programmable Self-Assembly of Robotic Modules

Programmable self-assembly of chained robotic systems holds potential for the automatic construction of complex robots from a minimal set of building blocks. However, current robotic platforms are limited to modules of uniform rigidity, which results in a limited range of obtainable morphologies and thus functionalities of the system. To address these challenges, we investigate in this paper the role of softness in a programmed self-assembling chain system. We rely on a model system consisting of “soft cells” as modules that can obtain different mechanical softness presettings. Starting from a linear chain configuration, the system self-folds into a target morphology based on the intercellular interactions. We systematically investigate the influence of mechanical softness of the individual cells on the self-assembly process. Also, we test the hypothesis that a mixed distribution of cells of different softness enhances the diversity of achievable morphologies at a given resolution compared to systems with modules of uniform rigidity. Finally, we illustrate the potential of our system by the programmable self-assembly of complex and curvilinear morphologies that state-of-the-art systems can only achieve by significantly increasing their number of modules

A Perching Mechanism for Micro Aerial Vehicles

Micro Aerial Vehicles (MAVs) with perching capabilities can be used to efficiently place sensors in aloft locations. A major challenge for perching is to build a lightweight mechanism that can be easily mounted on a MAV, allowing it to perch (attach and detach on command) to walls of different materials. To date, only very few systems have been proposed that aim at enabling MAVs with perching capabilities. Typically, these solutions either require a delicate dynamic flight maneuver in front of the wall or expose the MAV to very high impact forces when colliding head-first with the wall. In this article, we propose a 4.6g perching mechanism that allows MAVs to perch on walls of natural and man- made materials such as trees and painted concrete facades of buildings. To do this, no control for the MAV is needed other than flying head-first into the wall. The mechanism is designed to translate the impact impulse into a snapping movement that sticks small needles into the surface and uses a small electric motor to detach from the wall and recharge the mechanism for the next perching sequence. Based on this principle, it damps the impact forces that act on the platform to avoid damage of the MAV. We performed 110 sequential perches on a variety of substrates with a success rate of 100%. The main contributions of this article are (i) the evaluation of different designs of perching, (ii) the description and formal modeling of a novel perching mechanism, and (iii) the demonstration and characterization of a functional prototype on a microglider

Aerial Locomotion in Cluttered Environments

Many environments where robots are expected to operate are cluttered with objects, walls, debris, and different horizontal and vertical structures. In this chapter, we present four design features that allow small robots to rapidly and safely move in 3 dimensions through cluttered environments: a perceptual system capable of detecting obstacles in the robot’s surroundings, including the ground, with minimal computation, mass, and energy requirements; a flexible and protective framework capable of withstanding collisions and even using collisions to learn about the properties of the surroundings when light is not available; a mechanism for temporarily perching to vertical structures in order to monitor the environment or communicate with other robots before taking off again; and a self-deployment mechanism for getting in the air and perform repetitive jumps or glided flight. We conclude the chapter by suggesting future avenues for integration of multiple features within the same robotic platform