the surface fibers are very badly damaged and become unevenly distributed leaving a gap, the internal bladder may inflate through the gap and rupture. As with all pneumatic systems it is important that they are not operated when damaged. Hydraulic operation Although the technology is primarily pneumatically (gas) operated, there is nothing that prevents the technology from also being hydraulically (liquid) operated. Using an incompressible fluid increases system rigidity and reduces compliant behavior. In 2017, such a device was presented by Bridgestone and the Tokyo Institute of Technology, with a claimed strength-to-weight ratio five to ten times higher than for conventional electric motors and hydraulic cylinders. See also Artificial muscle Electroactive polymer Exoskeleton Notes External links Pneumatic Artificial Muscles: actuators for robotics and automation Bas Overvelde's ballooning muscles Pneumatic artificial muscles Biped robot powered by pneumatic artificial muscles Soft Robot Manipulators with McKibben muscles Air Muscles from Images Company Air Muscles from Shadow Robots Robotics hardware Pneumatic actuators