Knowledge Bank

Soft robotics is an important frontier in robotics research. Due to the high compliance of soft robots, they can be extremely durable, less likely to damage the surrounding environment, and much safer for use around humans. These attributes are particularly desirable for “co-robots,” or robots which share their workplace with people. However, soft robots lack the positional accuracy and load capabilities of traditional rigid robots. As such, there is a desire to create robots which combine the capabilities of traditional ridged robots with the safety of soft robots. Previous research has demonstrated a variable stiffness technology known as pneumatic-actuated layer jamming. The goal of this project was to build to a variable-stiffness robotic arm link utilizing this layer jamming technology to achieve the precision and load capabilities of a traditional robot and the safety of a compliant soft robot. To determine the best design for this arm, a test rig was set up to evaluate the stiffness of different layer jamming samples. Samples of various designs and materials were tested, and a positive relationship between the number of layers and the maximum stiffness was observed. A configuration with a high maximum stiffness was selected to give the robotic arm high load capabilities, and a prototype arm was built and evaluated. In the future, this type of robotic arm could safely work around humans by adjusting its stiffness in real time to ensure that it is in a safe, flexible state when contact with a person might occur.