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Soft and tensegrity structures are two configurations that have appeared as robots continue to draw inspiration from nature and diversify beyond rigid machines toward compliant systems. One artificial manifestation of a biological attribute that is an active research topic is the body's capacity to calibrate its stiffness for adapting its behavior to a given task. This study brings together these designs spaces and presents a soft tensile element named FlexiStiff for tensegrity structures to enable transitioning between flexible and stiff states for variable load‐bearing capability and compliance. The device's tensile stiffness constant can be increased by 4400% with a change in pressure. It can provide a high blocking force of 535.5 N and can endure elongation up to 184%. It is assembled using four commercially available materials and a two‐step fabrication method consisting of 3D printing and elastomer curing. As opposed to classical tensegrities for which shape change is inexpensive in terms of energy, this work betokens a new stage in their design wherein the arrangement can radically alter the magnitude of its demand for external energy for shape morphing, a crucial characteristic for operation in partially mapped environments that present diverse terrains and disturbances of varying intensities prompting adaptability. [ABSTRACT FROM AUTHOR]

Existing pneumatic artificial muscles generally rely on the use of either positive or negative pressure for actuation with each having their own advantages and disadvantages. Herein, a hyperbaric vacuum‐based artificial muscle (Hyper‐VAM) making use of both positive and negative pressures almost interchangeably is described. This is done by placing a vacuum‐based actuator inside a hyperbaric chamber which enables both the large deformations possible using negative pressure, and large forces through the action of high pressure differential, exceeding those possible using only negative pressure. This actuator can lift heavy payloads (up to 80 kg) for its entire contraction range, with large deformations (89.1% contraction of the active length) and high power (maximum power of 101.3 W), while using relatively low pressures, which can be supplied by a portable pneumatic pump. By exchanging air between the two chambers in closed‐loop pneumatic actuation, this actuator can also be driven using a single pump without exchanging air with the environment and its position can be controlled using a single pneumatic regulator. [ABSTRACT FROM AUTHOR]

To make robots more human-like and safer to use around humans, artificial muscles exhibiting compliance have gained significant attention from researchers. However, despite having excellent performance, pneumatic artificial muscles (PAMs) have failed to gain significant traction in commercial mobile applications due to their requirement to be tethered to a pneumatic source. This study presents a thermo-PAM called Thermo-PAM that relies on heating of a volume of air to produce a deformation. This allows for pneumatic actuation using only an electrical power source and thus enables pumpless pneumatic actuation. The actuator uses a high ratio between the heating volume and the deformable volume to produce a high actuation force throughout its entire motion and can produce either contractile or extension motions. The controllability of the actuator was demonstrated as well as its ability to handle heavy payloads. Moreover, it is possible to rely on either positive or negative pressure actuation modes where the positive pressure actuation mode actuates when heated and the negative pressure actuation mode relaxes when heated. The ability to use Thermo-PAMs for different modes of actuation with different operation methods makes the proposed actuator highly versatile and demonstrates its potential for advanced pumpless robotic applications.