Pneumatic Networks for Soft Robotics that Actuate Rapidly

Abstract

Soft robots actuated by pressurization and inflation of a pneumatic network (a "pneunet") of small channels in elastomeric materials are appealing for their ability to produce sophisticated motions with simple controls. Although current designs of pneu-nets achieve motion with large amplitudes, they do so relatively slowly (that is, over seconds). This paper describes a new design for pneu-nets that reduces the amount of gas that must be transported for inflation of the pneu-net, and thus increases its speed of actuation. A simple actuator can bend from a linear shape to a quasi-circular shape in 50 milliseconds when pressurized at ΔP = 345 kPa. At high rates of pressurization and inflation, the path along which the actuator bends depends on this rate. When inflated fully, the channels and chambers of this new pneu-net design experience only one-tenth the change in volume of that required for a motion of equal amplitude using the previous design. This small change in volume requires comparably low levels of strain in the material at maximum amplitudes of actuation, and commensurately low rates of fatigue and failure. This actuator can operate over a million cycles without significant degradation of performance. This design for soft robotic actuators combines high rates of actuation with high reliability of the actuator, and opens new areas of application for them.

Buckling Pneumatic Linear Actuators Inspired by Muscle

“…[1][2][3][4][5][6][7][8] They also offer an attractive approach to simplifying control, [5][6][7][8] since they make it possible-in some circumstances-to substitute the properties of soft materials and structures for some of the control loops, sensors, and actuators of hard machines (machines fabricated in metals, ceramics, and structural polymers). [9,10] The simplification of control is important in the field of robotics as a potential strategy for designing robots that work in unstructured environments.…”

Skins and Sleeves for Soft Robotics: Inspiration from Nature and Architecture

“…one channel actuation at increasing pressure. 16 Inspired by the formability of dragonskin scales, the concept also been used in architecture given the high formability of dragon skin designs (Figure 6(a)), a three-pneumatic channel module was designed made from Ecoflex 0050, with a corrugated sheet of the harder Dragonskin 0030, and the corrugated sheet gaps were filled the soft Ecoflex 0030, as is presented in the CAD model of Figure 6(b). FEA of one-channel actuation to 90 o bending in Figure 6(b) shows minimum ballooning for the innovative design.…”

“…[15] Ingenious designs of pneumatic networks can bring intelligent actuation patterns and create coordinated system motion or deformation. [16] On the other hand individual pneumatic chambers can create bending modes in different directions via mechanisms of chamber elongation or ballooning effect. Figure 1 displays a soft cylindrical module with three pneumatic chambers which upon individual pneumatic actuation offer bending in three directions.…”

Buckling of Elastomeric Beams Enables Actuation of Soft Machines

“…[4,5] The first generation of these systems-originally sketched by Suzumori, [6][7][8] and then realized and elaborated by us, [5,[9][10][11][12][13] and by others [4] -use pneumatic actuators, comprising networks of micro-channels; in our systems, differential expansion of these pneumatic networks (PneuNets) by pressurization using air produces motions (especially bending, curling, and variants on them) that are already established as useful in grippers, and interesting for their potential in walkers, tentacles, and a number of other soft, actuated systems. [14] 4 Although the design of the first of these systems has been relatively simple, the motion they produce on actuation can be surprisingly sophisticated: for example, a representative structure-the "finger" or "tentacle" of a gripper-curls non-uniformly, starting from its tip and proceeding to its stem, although the pressure applied in the PneuNet is approximately uniform throughout the system of inflatable channels.…”