WAKE-up exoskeleton to assist children with Cerebral Palsy: design and preliminary evaluation in level walking.

This paper presents the modular design and control of a novel compliant lower limb multi-joint exoskeleton for the rehabilitation of ankle knee mobility and locomotion of pediatric patients with neurological diseases, such as Cerebral Palsy (CP). The device consists of an untethered powered knee-ankle-foot orthosis (KAFO), addressed as WAKE-up (Wearable Ankle Knee Exoskeleton), characterized by a position control and capable of operating synchronously and synergistically with the human musculoskeletal system. The WAKE-up mechanical system, control architecture and feature extraction are described. Two test benches were used to mechanically characterize the device. The full system showed a maximum value of hysteresis equal to 8.8 % and a maximum torque of 5.6 N m/rad. A Pre-clinical use was performed, without body weight support, by four typically developing children and three children with CP. The aims were twofold: (i) to test the structure under weight-bearing conditions and (ii) to ascertain its ability to provide appropriate assistance to the ankle and the knee during overground walking in a real environment. Results confirm the effectiveness of the WAKE-up design in providing torque assistance in accordance to the volitional movements especially in the recovery of correct foot landing at the start of the gait cycle.