Macro-continuous dynamics for hyper-redundant robots: application to locomotion bio-inspired by elongated animals

International audienceThis article presents a unified dynamic modeling approach of continuum robots. The robot is modeled as a geometrically exact beam continuously actuated through an active strain law. Once included into the geometric mechanics of locomotion, the approach applies to any hyper-redundant or continuous robot devoted to manipulation and/or locomotion. Furthermore, exploiting the nature of the resulting models as being a continuous version of the Newton-Euler models of discrete robots, an algorithm is proposed which is capable of computing the internal control torques (and/or forces) as well as the rigid overall motions of the locomotor robot. The efficiency of the approach is finally illustrated through many examples directly related to the terrestrial locomotion of elongated animals as snakes, worms or caterpillars and their associated bio-mimetic artifacts

Gait Design for a Snake Robot by Connecting Curve Segments and Experimental Demonstration

This paper presents a method for designing the gait of a snake robot that moves in a complicated environment. We propose a method for expressing the target form of a snake robot by connecting curve segments whose curvature and torsion are already known. Because the characteristics of each combined shape are clear, we can design the target form intuitively and approximate a snake robot configuration to this form with low computational cost. In addition, we propose two novel gaits for the snake robot as a design example of the proposed method. The first gait is aimed at moving over a flange on a pipe, while the other is the crawler gait aimed at moving over rough terrain. We demonstrated the effectiveness of the two gaits on a pipe and rough terrain in experiments

HISSbot: Sidewinding with a Soft Snake Robot

Snake robots are characterized by their ability to navigate through small spaces and loose terrain by utilizing efficient cyclic forms of locomotion. Soft snake robots are a subset of these robots which utilize soft, compliant actuators to produce movement. Prior work on soft snake robots has primarily focused on planar gaits, such as undulation. More efficient spatial gaits, such as sidewinding, are unexplored gaits for soft snake robots. We propose a novel means of constructing a soft snake robot capable of sidewinding, and introduce the Helical Inflating Soft Snake Robot (HISSbot). We validate this actuation through the physical HISSbot, and demonstrate its ability to sidewind across various surfaces. Our tests show robustness in locomotion through low-friction and granular media.Comment: 7 pages, 9 figures, to be published in RoboSoft 202

A Snake-Inspired Multi-Segmented Magnetic Soft Robot Towards Medical Applications

Magnetically-actuated soft robots have potential for medical application but require further innovation on functionality and biocompatibility. In this letter, a multi-segmented snake-inspired soft robot with dissolvable and hiocompatible segments is designed. The actuation response under external magnetic field is investigated through simulations and experiments. A dissolve-controllable mixture of gelatin, glycerol and water (GGW) in a mass ratio of 1:5:6 is used to form the structure of the robot. The dissolution of GGW in water and mucus is tested. Magnetic cubes made of silicone rubber mixed with ferromagnetic particles are used to achieve snake-like motion under the influence of a rotating magnetic field. The motion of the robot is tested under different magnitudes and frequencies of the magnetic field. The ability of the robot to navigate obstacles, move over ground and under water as well as on the oil-coated surface, dissolve and release a drug is demonstrated through experiments. The combination of multi-segmented design and biocompatible and dissolvable materials illustrates the potential of such robots for medical applications

Design and Fabrication of Origami Elements for use in a Folding Robot Structure

The aim of the research is to investigate the methodology of the design and fabrication of folding robots that depend on the origami structures. The use of origami structures as a foundation to build reconfigurable and morphing robots that could assist in search and rescue (SAR) tasks are investigated. The design of the origami folding structures divided into three stages: consideration of the geometry of the origami structure, the hinge design, and the actuation system. The result of investigating three origami structures shows the ability to use the unit cell of the origami ball structure as a self-folding element. Furthermore, the novel type of origami structure for manipulation was created according to this result. This novel structure was designed to be a soft manipulation robot arm. Two approaches are used to design and fabricate flexure hinge. The first is by using a 3D printed multi-material technique. By this technique, the hinge printed using soft and solid material at the same time, which is Tango plus flx930 for soft material and Vero for solid material. The soft material act as a flexure hinge. Therefore, three tests were operated for it to calculate the tensile force, fatigue limit, and the required bend force. The second approach is by using acrylic and Kapton materials. Two types of actuation systems were studied: the external actuation system and embedded actuation system. The external actuation system was used for the Origami structure for manipulation, while the embedded actuation system was used for the self-folding structure. The shape memory alloy wires in torsion (TSW) and bending (BSW) was used in an embedded actuation system. A unit cell of origami ball was fabricated as a self-folding element by using three approaches: manually, acrylic, and Kapton and 3D printing. It is actuated by using shape memory alloy wire. Furthermore, an origami structure for manipulation was fabricated and actuated using an external actuation system. This novel type of origami structure provided an excellent bend motion ability