Motion path planning and simulation for a waist rehabilitation robot based on a Stewart parallel platform

For patients with lumbar disorders requiring specialized rehabilitation intervention after clinical treatment, this paper designs a lumbar rehabilitation robot based on a 6-UPU Stewart parallel platform. First, the structural design is completed according to the physiological dimensions and range of motion of the human lumbar spine. The robot can mimic human lumbar rehabilitation movements such as flexion, extension, lateral flexion, and rotation. Subsequently, a kinematic model is established for forward and inverse kinematic analysis to validate the mechanism's rationality. Finally, based on inverse kinematics, programming in MATLAB was used to solve for the drive link lengths under different rehabilitation postures and perform kinematic simulations for various configurations. The results demonstrate that the Stewart platform exhibits smooth motion and excellent compliance during routine rehabilitation movements. Its motion errors remain within acceptable limits for human tolerance, thereby meeting the requirements for patients' daily rehabilitation training.