Design of a Lower Limb Rehabilitation Robot Based on 3-RPR Parallel Mechanism

As the population ages, the need for rehabilitation robots is becoming greater and greater. Considering that lower limb motion plays an important role in the activities of daily life. This paper focus on developing a 3-degree of freedom bionic knee lower limb exoskeleton rehabilitation robot. The exoskeleton consists of a 1-DOF hip joint and 2-DOF knee joint in the sagittal plane. According to the theory of human gait and lower limb structure, a 3-RPR (Revolute pair - Prismatic pair - Revolute pair) parallel mechanism was designed to fully accommodate the motion of the human knee joint and obtain the trajectory of lower limb. The parameters of the mechanism was optimized based on maximizing the useful work space. In order to enable people of different height to use the exoskeleton robot, we designed a leadscrew nut mechanism to adjust the length of the exoskeleton steplessly. Compared with other traditional lower limb exoskeleton robots, this robot has the characteristics of compact structure and bionic knee joint. In order to verify the feasibility of this exoskeleton, a simulation based on MATLAB and ADAMS was performed.