Variable stiffness adaptation to mitigate system failure in inflatable robots

Although inflatable soft robots are not yet a common robot platform, air leaking from the internal structure is a common and undesirable mode of failure for these platforms. In this paper we demonstrate a method to detect leaks in the structural chamber of an inflatable, pneumatically actuated robot. We then show that our method can adaptively lower commanded joint stiffness which slows the mass flow rate of the leak. This extends the operational life of the robot by decreasing long term error during operation by as much as 50% of the steady state error at the end effector when compared to the same leak if our adaptation method is not used. In future applications where we expect soft, inflatable robots to be useful, our methods can enable failure mitigation in resource-limited situations such as space exploration or disaster response.