Kinematic and Kinetic Analysis of 3-RPR Based Robotic Lumbar Brace

Human spine has functions of load-bearing, shock absorption, protection and movement. Spine deformity seriously affects the daily life of patients and reduces the quality of life. Recent ideas of using robotic braces start a new form of rehabilitation for patients with spine deformity. In this paper, we presented a robotic lumbar brace for the potential application to scoliosis rehabilitation. The robotic brace is designed based on a 3-RPR parallel mechanism and consists of three degrees of freedom: horizontal, vertical, and rotational motions of moving platform relative to the fixed platform in the coronal plane. The robotic lumbar brace interferes with the condition of the spine by changing the position of the thorax relative to the pelvis in the coronal plane in order to relieve or correct scoliosis. The linear actuator is customized to meet the need for greater correction force. Kinetic analysis and kinematic analysis which includes inverse kinematics and forward kinematics are demonstrated in detail. The force and moment of robotic lumbar brace support on thorax during the movement can be calculated timely through kinetic analysis. The proposed robotic lumbar brace may have potentials in scoliosis rehabilitation.