[Picture credits: Tommaso Ranzani]
One of the problems of soft robotics is that some tasks required a high a degree of precision. Knowing exactly where your end effector is crucial and being able to control the “stiffness” of the system is a plus when you need accuracy.
Today I stumbled upon a paper that has a novel approach to deal deal with this issues. It’s a bioinspired soft manipulator by Dr. Tommaso Ranzani (http://iopscience.iop.org/1748-3190/10/3/035008). The manipulator is consists of small segments of Silicone. Each segment has four chambers. Tree chambers are inflatable, and by controlling their air pressure, you can move the manipulator around. Pumping two at the same time move the manipulator toward the deflated one, pumping all tree, extends the manipulator. There is a 6 DOF sensor in each junction. By modeling the orientation of each junction and the length of the segments they can calculate the position of the tip.
So far nothing new. The genius is in the central chamber. This central chamber is filled with granular material (ex. coffee) and by controlling the pressure in this chamber they can controll the stiffness of the system.
It’s the same principle behind John Amend’s and Hod Lipson’s universal robotic gripper.