Design, Computational Modelling and Experimental Characterization of Bistable Hybrid Soft Actuators for a Controllable-Compliance Joint of an Exoskeleton Rehabilitation Robot

This paper presents the mechatronic design of a biorobotic joint with controllable compliance, for innovative applications “assist-as-needed” robotic rehabilitation mediated by wearable and soft exoskeleton. The actuation exoskeletons can provide some relevant advantages in terms adaptivity intrinsic safety control performance robot during interaction patient. Pneumatic Artificial Muscles (PAMs), which belong to class actuators, be arranged antagonistic configuration order exploit variability their mechanical compliance optimal adaptation therapy. coupling an PAMs regulation mechanism achieve, under customized strategy, tuning exoskeleton over full ranges pressure rotation. work novel mechanism, joint, is characterized hybrid exploiting storage/release elastic energy bistable Von Mises trusses. contribution from structure improve both response pneumatic bellows actuating whole mechanism. A comprehensive set steps presented here, including optimization geometry bellows, fabrication process through 3D printing experimental tests devoted characterization actuation. replicated main operating conditions mechanism; arising were evaluated static dynamic performance, e.g., force transition thresholds linearity hysteresis actuator response.