Figure 4. Bioinspired application of an osmotic pressure generator for actuation of a soft robot.

A. Design concept of a previously described elastomeric soft robot whose arms curve and can grip objects in response to pressurization of parallel channels with boundaries of differing thickness. Adapted from [17]. B. Guard cells in their open and closed states. Thick interior walls make guard cells curl when osmotically pressurized, opening stomata. Adapted from [28]. C. Actuation of the soft robotic gripper used in this work in response to watering an attached osmotic pressure generator. The extent of deflection is shown after 1, 2, and 3 hours. D. System pressure and deflection angle (as defined in C) of the gripper as a function of time.