Modal decoupled dynamics-velocity feed-forward motion control of multi-dof robotic spine brace

Based on the parallel robotic manipulator, this paper proposes a motion control strategy for the novel robotic spine brace for spinal rehabilitation exercises. However, several shortcomings of this parallel robotic manipulator, such as dynamic coupling in joint space, low response frequency in roll and pitch directions, and bad influence of device's gravity, result in bad effects on the performance of the robotic spine brace system. For solving these problems of parallel robotic manipulator, a new motion control structure, modal space dynamics-velocity feed-forward (MSDF) motion control strategy, is designed in this paper. A robotic spine brace system model and an actuator dynamic model are expressed using the Kane method. Stability of the robotic system with the MSDF control method is analyzed. For evaluating the performances of the proposed motion control structure, an experimental parallel robotic manipulator is built. Experimental results reveal that the presented MSDF motion control strategy can eliminate those disadvantages efficiently.