Safe robot therapy: Adaptation and usability test of a three-position enabling device for use in robot mediated physical therapy of stroke

Safe therapeutic robot systems must be equipped with, among other, safety devices and enabling devices. Enabling devices were developed first for the operators of industrial systems for ensuring the safety thresholds during a short term presence in the safeguarded area. On the contrary, enabling devices for therapy robots must be continuously operated by the patients during the treatment session to permit therapy. The enabling devices used in therapy robotics, and in the broader sense rehabilitation robotics must adhere to different requirements than their industrial versions. The authors review the current legal framework that should be considered during the development of therapy robots. The authors analyze also the safety technologies used in key existing therapy robot systems. The central part of the paper describes the adaptation of an industrial three-position enabling device to the requirements of stroke upper limb therapy. The new device is intended to use with the REHAROB that is a robotic system for upper limb physiotherapy. The usability of the three-position enabling device was tested by 9 healthy volunteers and by 12 hemiparetic subjects with success.