Safety and handling concept for assistive robotic devices with pneumatic rotary soft-actuators

Compliance and assistive behavior are essential properties for safe physical human-robot interaction (HRI), an illustrative example for which is robot aided motion therapy. These requirements can be easily fulfilled using inherent compliant and back-drivable (i.e. soft) actuators. This paper describes a fully functional prototype for assistive robotic knee MTD with novel inherent compliant (soft) fluidic actuators of rotary type, which has been developed for orthopedic rehabilitation purposes. Assistive acting motion therapy devices (MTD) are mainly used for neurologic treatment until now, but become increasingly important for orthopedic rehabilitation as well. Device capabilities provide human-like treatment and allow individual adjustable assistance to accomplish desired motions. Utilization of pneumatic soft-actuators demands a special safety concept which is merged with control algorithms to provide sufficient safeness and to catch any possible system errors and sudden emergency situations. A self descriptive user interface allows easy intuitive handling and the prototype can be used very comfortable due to several imperceptible working routines in the background. The same safety and handling concept is used for assistive robotic shoulder MTD, which is currently being developed.