Lower Limb Exoskeleton Robot Control Design Based on TP Transformation

This paper presents a method to transform a nonlinear lower limb exoskeleton robot system into a linear convex polyhedron model using tensor product (TP) model transformation. The angle and angular acceleration information of the hip joint and the knee joint of the robot are taken as variable parameters, and the dynamic equation of the flexible joint robot is divided isometric and stored in the tensor. Then, higher-order singular value decomposition (HOSVD) is used to compute the singular value of the tensor and the corresponding eigenvector. The polyhedron model’s weight function is constructed using the eigenvectors, and a linear time-invariant (LTI) system with finite vertices is obtained. Then linear matrix inequality (LMI) is used to solve the controller. Finally, a simulation of trajectory tracking is carried out, and the simulation results show the effectiveness of the proposed strategy.