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This letter presents MAMMOBOT, one of the first millimetre-scale steerable soft growing robots for medical applications. MAMMOBOT aims to access the breast through the nipple and navigate the mammary ducts to detect precursors of invasive breast cancers. Addressing limitations of the state-of-the-art, MAMMOBOT maintains a hollow inner lumen throughout its soft body, enabling the passing of instruments such as miniature endoscopes, biopsy needles, and optical probes for in situ histopathology. MAMMOBOT is developed by a novel manufacturing approach entailing dual LDPE sheet adhesion with localised heat treatment. MAMMOBOT's steerability is achieved through a sub-millimetre profiled tendon-driven catheter that passes through its inner lumen. A duty cycle controller governs steering versus growing to achieve navigation in complex environments within a human-in-the-loop framework. Benchtop experimental evaluation demonstrates the robot's capabilities and agreement with a Reduced-Order Mode (ROM) of its dynamics. Finally, experimental evaluation on a bespoke breast phantom developed for the purposes of this project demonstrates the clinical relevance and potential impact of MAMMOBOT.

Mammals like rats, who live in dark burrows, heavily depend on tactile perception obtained through the vibrissal system to move through gaps and to discriminate textures. The organization of a mammalian whisker follicle contains multiple sensory receptors and glands strategically organized to capture tactile sensory stimuli of different frequencies. In this paper, we used a controllable stiffness soft robotic follicle to test the hypothesis that the multimodal sensory receptors together with the controllable stiffness tissues in the whisker follicle form a physical structure to maximize tactile information. In our design, the ring sinus and ringwulst of a biological follicle are represented by a linear actuator connected to a stiffness controllable mechanism in-between two different frequency-dependent data capturing modules. In this paper, we show for the first time the effect of the interplay between the stiffness and the speed of whisking on maximizing a difference metric for texture classification.

In the past decade, the use of soft, deformable materials has gained widespread interest due to their potential to carry out tasks in unstructured environments, such as grasping or manipulating objects with a wide variety of shapes and sizes, locomotion in irregular terrains, and enabling safe and flexible interactions between humans and robots. This emerging research field, generally known as soft robotics, also pushes the boundaries of visionary research topics, such as self-growing and self-healing robotic systems.

Various methods based on hyperelastic assumptions have been developed to address the mathematical complexities of modeling motion and deformation of continuum manipulators. In this study, we propose a quasistatic approach for 3D modeling and real-time simulation of a pneumatically actuated soft continuum robotic appendage to estimate the contact force and overall pose. Our model can incorporate external load at any arbitrary point on the body and deliver positional and force propagation information along the entire backbone. In line with the proposed model, the effectiveness of elasticity versus hyperelasticity assumptions (neo-Hookean and Gent) is investigated and compared. Experiments are carried out with and without external load, and simulations are validated across a range of Young's moduli. Results show best conformity with Hooke's model for limited strains with about 6% average normalized error of position; and a mean absolute error of less than 0.08 N for force applied at the tip and on the body, demonstrating high accuracy in estimating the position and the contact force.

Several semi-analytical models are considered for a double-gyre problem in a turbulent flow regime for which a reference fully numerical eddy-resolving solution is obtained. The semi-analytical models correspond to solving the depth-averaged Navier–Stokes equations using the spectral Galerkin approach. The robustness of the linear and Smagorinsky eddy-viscosity models for turbulent diffusion approximation is investigated. To capture essential properties of the double-gyre configuration, such as the integral kinetic energy, the integral angular momentum, and the jet mean-flow distribution, an improved semi-analytical model is suggested that is inspired by the idea of scale decomposition between the jet and the surrounding flow.

Hybrid rigid-continuum robot design addresses a range of challenges associated with using soft robots in application areas such as robotic surgery. Design of such robots poses challenges beyond standard rigid-body robots. A fast, reliable, accurate yet simple dynamic model is important to support the design, analysis, and control of hybrid rigid-continuum robots. In our previous work, we developed a modeling package for hybrid rigid-continuum systems, named TMTDyn. In this paper, we focus on how we developed an internal domain-specific language (DSL) using Matlab's OO capabilities and the concept of fluent interfaces to improve validation, understandability, and maintainability of the models constructed using TMTDyn. We present the language implementation, and discuss some of the benefits and challenges of building a Matlab-internal DSL.

Cat free fall righting maneuverer has inspired many aerial, space and legged robotic research. Conservation of angular momentum principle is used to derive the inverse differential kinematic and TMT vector form dynamics of the motion for three robotic models: a two-link model, a three-link model with tail, and a comprehensive eight-link model with the addition of legs. The path planning problem in the presence of geometric and kinematic constraints is addressed using a novel singularity free single shooting optimization method. While a 2 DOF torso is sufficient to perform a full maneuver, the addition of the tail reduces the time and increases the maneuverability despite the leg motions that has adverse effects. The method performance is investigated numerically and a simulation in MSC.ADAMS software is used to verify the results. The structural parameters are optimized showing the significant advantageous of a light and symmetric body shape. A prototype will be fabricated based on these results in near future.

Passive walkers perform a walking like stable limit cycle on small slopes without any external control. In this research, a deployed model of biped that can be built has been considered, and then its walking performance sensitivity such as efficiency, stability and robustness on uneven trains due to variation of structural parameters and their optimum limits have been investigated. It was shown that the foot arc radius and center of mass height have the most important effect on walking performance. After doing simulations in MSC.ADAMS software, an optimum design trend has been suggested. At the end based on experimental results, it was shown beside optimization of structural parameters, the impact condition is very important to achieve optimal walking.

Smart attachment mechanisms are believed to contribute significantly in stiffness control of soft robots. This paper presents a working prototype of an active Velcro based stiffness controllable fastening mechanism inspired from micro active hooks found in some species of plants and animals. In contrast to conventional passive Velcro, this active Velcro mechanism can vary the stiffness level of its hooks to adapt to external forces and to maintain the structure of its supported layer. The active hooks are fabricated using Shape Memory Alloy (SMA) wires which can be actuated using Lenz-Joule heating technique via thermo-electric manipulation. In this paper, we show experimental results for the effects of active SMA Velcro temperature, density and number on the attachment resisting force profile in dynamic displacement. We aim to provide new insights into the novel design approach of using active hook systems to support future implementation of active velcro mechanisms for fabrication of wearable stiffness controllable thin layers.

We investigate how unmanned aerial vehicles (UAVs) with flexible wings can be designed to exploit the aeroelasticity of wing deformation that is present in bat wings, with a view to improve the efficiency of flight. We constructed a robotic bat wing with fully passive elastic wing-folding properties. The robotic wing is powered by a gearbox running two synchronised motors, effectively providing one degree of motion: the upstroke and down-stroke of the wing. Through numerical simulations and setup experiments, we observed that by integrating a span-wise elastic network into the bat wing, we were able to achieve passive wing-folding that mimics the 8-shape wing-folding seen in bats' high speed flight. This way, we were able to reduce the complexity and additional actuation associated with wing-folding in a robotic wing.