Design of a bioinspired cable driven actuator with clutched elastic elements for the ankle.

Bioinspiration can be used to improve the efficiency of these assistive biomechatronic devices. In this paper, a cable driven actuator for the human ankle was designed using a bioinspired approach. The torque reduction was achieved by means of force amplifying elements such as cables with pulley, and, to reduce the power requirements for the motor, the actuator mimics a muscle using a clutched parallel elastic element. The simulations to validate the model were performed using real gait data and the results prove the viability of the device to be used in anthropomorphic legs and exoskeletons. Although the losses due to friction were not considered, the simulations showed a reduction of 60% in the force peak and 40% in the power peak.

Kinect v2 based system for gait assessment of children with cerebral palsy in rehabilitation settings.

Cerebral palsy (CP) describes a group of disorders of movement, posture and balance caused by a non-progressive brain injury in the immature brain. It is the most prevalent cause of chronic motor disability in childhood, and although two thirds of CP children are able to walk, they show gait limitations. In this context, rehabilitation therapy can improve muscle balance and gait. Previous studies showed the importance of gait analysis as part of multidisciplinary tools for effective rehabilitation treatment. However, the high cost and the infrastructure required for the implementation of commercial gait analysis systems as well as the time-consuming preparation procedures, limit the access to this service. A low cost, non-restrictive, portable and of simple operation and installation system was developed based on Kinect v2 sensor. This study aims to validate it for capturing and analysing gait parameters in children with cerebral palsy. Several gait parameters from eleven CP patients with different levels of disability classified as a function of the Gross Motor Function Classification System (GMFCS) from II to III were recorded while they walked on a flat surface. The Kinect-based gait analysis system was compared with video-recording that yielded the same results. These results show the potential of Kinect to analyse gait in frail patient populations unobtrusively and with very low cost. More importantly, regarding to spatial parameters, the Kinect system was useful even for the worst case of GMFCS III that show a large gait variability with abnormal patterns.