Dynamic Modeling and Performance Analysis of a New Redundant Parallel Rehabilitation Robot

The inverse dynamic model and performance analysis of a new redundant parallel rehabilitation robot are presented in this paper. First, the kinematics of each part is analyzed based on a closed-loop vector chain method. Then, the dynamic model of each part is formulated based on the D'Alembert principle and Euler's equation. After that, the inverse dynamic formulation of the new redundant parallel robot is established by utilizing the principle of virtual work and the concept of linked Jacobian matrices. To validate the approach, dynamic simulations are implemented in ADAMS and MATLAB. The results demonstrate the correctness of this dynamic formulation. Then, the actuating forces are optimized by utilizing the weighted Moore-Penrose generalized inverse method, which determines the minimum norm of the least quadratic sum among the possible actuating force vectors. Finally, two novel dynamic performance indices are defined. The first index reflects the coupling effect of other neighboring limbs to the dominant limb; the second reflects the coupling effect of each neighboring limb to the dominant limb. The proposed approach can be used for the dynamic performance analysis in other types of redundant parallel robots and provides a reference for dynamic control strategies.