Behaviour of axially crushed corrugated tubes

This article reviews soft pneumatic actuators (SPAs) that are manufactured entirely via additive manufacturing methods. These actuators are known as four-dimensional (4D)-printed SPAs and can gener...

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3D/4D-printed bending-type soft pneumatic actuators: fabrication, modelling, and control

A Timoshenko beam excited by a sequence of identical moving masses is studied as a time-varying problem. The effects of centripetal and Coriolis accelerations besides the vertical component of acceleration of the moving mass are considered. Using Galerkin procedure, the partial differential equations of motion which are derived by Hamilton’s principle are transformed to ordinary differential equations. The incremental harmonic balance method is implemented to determine the boundary curve of instability and other companion curves of resonance in the parameter plane. A new approach for identifying the conditions of resonance is investigated by presenting an intuitive definition of resonance for time-varying systems. The influence of employing different deformation theories on the critical parameter values of stability and resonance curves is studied. The validity of the instability and resonance curves is examined by numerical simulations and also ascertained through comparing with those reported in the literature.

On the parametric excitation of a Timoshenko beam due to intermittent passage of moving masses: instability and resonance analysis

The soft robotics field investigates biological bodies’ movements to develop soft actuation with similar behavior seen in nature. The skeletal muscles’ movements are vastly mimicked in soft actuators; however, the contractions of smooth muscles are overlooked in soft robotics. Smooth muscles provide peristaltic contractions to the digestive system, such as the stomach, and their design challenges the limits of soft robot development that simulates digestive organs. In this article, we present a novel, bellows-driven soft pneumatic actuator (SPA) with a self-sensing capability that generates linear displacement to simulate a smooth muscle segment in a stomach. This SPA is proposed as a solution for applications such as stomach simulators. The SPA concept, design, fabrication, creep model, and experimental validation are presented in this article. A lumped viscoelastic model presents the actuator's modeling to predict the SPA's displacement from a known applied pressure. The model is successfully validated, which resulted in a maximum displacement of 20.0 mm with a displacement error of 3%. A sensory system embedded in the SPA measures the displacement, and it is found that a force of 0–8.0 N is produced. A polynomial equation calibrates the sensor readings, with a displacement error of 5%. The results show the SPA's capability as a linear soft actuator that can generate a deformation like a smooth muscle segment. To simulate a circular contraction from a stomach with the SPA, we install multi-SPAs in a ring frame that performs contractions. Although the proposed SPA is specifically designed to mimic the smooth muscle, the ring actuator's contractions can be used for other applications such as gripping soft objects.

Design and Characterization of a Bellows-Driven Soft Pneumatic Actuator

Implantable splinting devices for supporting a passageway defect in a patient that is formed from one or more support structures including a polymer or a polymer and acellularized tissue matrix that define a structural component that substantially conforms to a defective passageway of the patient. The structural component also has a plurality of pores. The implantable splinting device is capable of being placed around a trachea, a bronchi, an esophagus and a blood vessel of a patient. The implantable splinting device may also be configured for placement between the trachea, and the esophagus of a patient.

J.F. Wilson

Papers

Mechanics of bellows: A critical survey

Responses of continuous, inertialess beams to traversing mass—A generalization of Stokes' problem