The simplest shape used for laminar jamming is that of rectangular sheets, Nevertheless, even the simplest shapes can achieve a number of conformations due to the shape-locking ability of Laminar Jamming Structures. Shape-locking enables LJS to achieve an arbitrary configuration when they are in their flexible state, lock in place after being jammed and resist static loading. When these jamming structures are used with soft actuators, they can save power by requiring no control effort to preserve the apparatus's shape, even if the actuation input is turned off. Furthermore, soft machines with high material strain (e.g. Pneumatic Artificial Muscles) can be deflated after locking, mitigating the risk of catastrophic rupture.
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On the left, you see a demonstration of the shape-locking ability of Laminar Jamming Structures by coupling one of them with Pneumatic Bending Actuators (PneuNets). PneuNets are soft actuators which bend when pressurized, but they return to their original shape when the pressure is relieved. In the experiment, a PneuNet is attached to an LJS and pressurized to obtain a desired bending angle. The jamming structure is activated by turning on vacuum, thus applying a pressure gradient that causes the LJS to lock in its stiff conformation. As a result, even when the PneuNet is depressurized, the system preserves its shape with high fidelity.
In addition, departures from the traditional rectangular shape can increase the range of shapes that Laminar Jamming Structures can achieve. Below you see videos of interesting geometries obtained after a woven mesh and a plus-shaped jamming structure were actively pressurized and depressurized by turning vacuum on or off.
