Assistive control concepts for pneumatic soft robotic rehabilitation devices

Robot-assisted rehabilitation becomes increasingly important in neurorehabilitation since the late 90s, because treatment times of physiotherapists are limited and expensive. In orthopedic rehabilitation, for more than 30 years, continuous passive motion (CPM) machines are used to support therapists, but these simple and inexpensive devices are only guiding the patient's motion and ignoring their own effort. Novel soft fluidic actuators based on rotary elastic chambers (REC-actuators) are very suited for direct human-robot interaction and provide the basis for the development of compact, modular and cost-effective soft robotic rehabilitation devices (SRRDs) interacting with humans. In this thesis, several assistive control concepts have been developed for SRRDs based on REC-actuators, that take into account specific actuator characteristics as well as the patient's individual behavior, effort and abilities without using force/torque sensors. To identify unknown mass parameters of SRRDs as well as of human's extremities, that are required for concept realization, an approach to estimate mass parameters based on a minimal number of experimental measurements has been developed. Algorithms are first investigated in simulation and afterwards verified using several prototypes of assistive SRRDs with healthy subjects as well as exemplarily with patients in orthopedic rehabilitation. The key result of this thesis is that using fluidic soft-actuators, the assistive control concepts can be realized without using force/torque sensors. Based on existing experimental data, it can be expected that assistive controlled cost-effective and compact SRRDs have the potential to improve the effectiveness of neurological and orthopedic rehabilitation.