Conceptual design of a rehabilitation device based on cam-follower and crank-rocker mechanisms hand actioned

Abstract

Several works present exoskeletons and devices acting in the hip, the knee and the ankle of patients with some kind of limitation on the lower limbs movement, aiding patients’ locomotion/rehabilitation. The challenges in exoskeletons development for paraplegics’ locomotion are related with obtaining a compact and low-mass design with long battery life. Furthermore, the robotic devices to lower limb rehabilitation are very expensive complex systems mainly due to the technology of servomotors, drivers and control system; thus, a simpler device tends to make patients feel more comfortable and safer, which is important to gain their acceptance. Hence, the aim of this paper is developing a new exoskeleton with one degree of freedom, low cost, to locomotion/rehabilitation of subjects with paralysis/motor disability in the lower limbs, powered by the user’s strength, reproducing on them the ability to walk with stability and security. This leads to decreasing the problems related to the lack of movement and the consequent improvement in the paraplegics’ life quality. The proposed device was developed using a combination of simple mechanisms to obtain the approximate human gait movement. In order to achieve the proposed objective, we present the mechanism synthesis, graphical simulations and experimental test of the simplified prototype built. The graphical simulations and the experimental results show that the proposed device performs properly on the hip and knee joints movement but with smaller amplitude.