Lower limb movement disorders caused by various reasons are an important public health problem currently facing the world. To solve this problem, a novel spatial 8R mechanism with a stable structure and motion performance for human hip joint rehabilitation is proposed. Since the human body mainly performs coronal and sagittal plane movements, a spatial 8R mechanism with 2-DOF was designed to assist patients in rehabilitation training considering their actual circumstances. Based on the analysis

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... of the Jacobian matrix and its condition number, the kinematics model and kinematics equation of the 8R mechanism in space were established. The mechanism has complete isotropic kinematics in single abduction and adduction, forward flexion and backward extension, and good dexterity and operability within the scope of the workspace; the correctness of the kinematics equation of the spatial 8R mechanism was verified by using the ADAMS software and theoretical calculation, and the regular variations of the mechanism's movement in one period under different motions were obtained. We concluded that the spatial 8R mechanism has a stable performance and can move smoothly.