High-throughput 2D-to-4D fabrication of magneto-origami machines

Magneto-active soft machines capable of magnetically controllable shape-morphing and locomotion have diverse promising applications such as untethered biomedical robots. However, existing magneto-active soft machines often show simple structures and limited deformation range. These technologies also suffer because mass production of the magneto-active machines is unavailable. Here, we propose a direct 2D-to-4D fabrication strategy that transforms 2D magnetic sheets into 3D magneto-active soft machines with customized geometries by incorporating origami folding. The method can be easily adapted to roll-to-roll processing. This approach enables a variety of unique characteristics of magneto-origami machines, including large-magnitude deploying, sequential folding into predesigned shapes and multivariant actuation modes (e.g., contraction, bending, rotation and rolling locomotion). We leverage these abilities to demonstrate a few potential applications: an electronic robot capable of on-demand deploying and wireless charging, a mechanical 8-3 encoder, and a quadruped robot for cargo-release tasks. Our work paves a way for the high-throughput fabrication of magneto-active soft machines with multi-functionalities.

Design and locomotion analysis of the tetrahedral mobile robot with only revolute joints (TMRR)

Purpose The purpose of this paper is to introduce a tetrahedral mobile robot with only revolute joints (TMRR). By using rotation actuators, the mechanism of the robot gains favorable working space and eliminates the engineering difficulties caused by the multilevel extension compared with liner actuators. Furthermore, the rolling locomotion is improved to reduce displacement error based on dynamics analysis. Design/methodology/approach The main body of deforming mechanism with a tetrahedral exterior shape is composed of four vertexes and six RRR chains. The mobile robot can achieve the rolling locomotion and reach any position on the ground by orderly driving the rotation actuators. The global kinematics of the mobile modes are analyzed. Dynamics analysis of the robot falling process is carried out during the rolling locomotion, and the rolling locomotion is improved by reducing the collision impulse along with the moving direction. Findings Based on global kinematics analysis of TMRR, the robot can realize the continuous mobility based on rolling gait planning. The main cause of robot displacement error and the corresponding improvement locomotion are gained through dynamic analysis. The results of the theoretical analysis are verified by experiments on a physical prototype. Originality/value The work introduced in this paper is a novel exploration of applying the mechanism with only revolute joints to the field of tetrahedral rolling robots. It is also an attempt to use the improved rolling locomotion making this kind of mobile robot more practical. Meanwhile, the reasonable engineering structure of the robot provides feasibility for load carrying.

An untethered isoperimetric soft robot

For robots to be useful for real-world applications, they must be safe around humans, be adaptable to their environment, and operate in an untethered manner. Soft robots could potentially meet these requirements; however, existing soft robotic architectures are limited by their ability to scale to human sizes and operate at these scales without a tether to transmit power or pressurized air from an external source. Here, we report an untethered, inflated robotic truss, composed of thin-walled inflatable tubes, capable of shape change by continuously relocating its joints, while its total edge length remains constant. Specifically, a set of identical roller modules each pinch the tube to create an effective joint that separates two edges, and modules can be connected to form complex structures. Driving a roller module along a tube changes the overall shape, lengthening one edge and shortening another, while the total edge length and hence fluid volume remain constant. This isoperimetric behavior allows the robot to operate without compressing air or requiring a tether. Our concept brings together advantages from three distinct types of robots—soft, collective, and truss-based—while overcoming certain limitations of each. Our robots are robust and safe, like soft robots, but not limited by a tether; are modular, like collective robots, but not limited by complex subunits; and are shape-changing, like truss robots, but not limited by rigid linear actuators. We demonstrate two-dimensional (2D) robots capable of shape change and a human-scale 3D robot capable of punctuated rolling locomotion and manipulation, all constructed with the same modular rollers and operating without a tether.

Path Planning for Rolling Locomotion of Polyhedral Tensegrity Robots Based on Dijkstra Algorithm

Tensegrity-based locomotive robots have attracted more and more interests from multidisciplinary engineering community. To realize long distance locomotion for tensegrity robots in a given land, path planning is usually needed. This paper proposes a path planning approach for rolling locomotion of polyhedral tensegrity robots. Given the start vertex, target vertex and the directed graph G which indicates the possible paths, the optimal path with lowest cost can be found by Dijkstra algorithm. Numerical and experimental examples are carried out with a six-bar tensegrity robot prototype. Both motion distance and terrain characteristics are considered within the cost. The proposed approach is generally verified by the examples. A comparison between the numerical result and the experimental result is also presented.