Dynamic Modeling and Stiffness Coefficient Analysis of a 3-DOF Flexible Joint Space Manipulator

In order to solve the problems of flexible joint space manipulators in dynamics modeling and simulation, a model with three-dimensional four-link flexible-joint manipulators is taken into account. Considering the nonlinear stiffness coefficient of the torsion-spring, and inertia coupling, the dynamics model of flexible-joint manipulators with revolute joints is established by applying the Lagrange method. The correctness of the model is tested and verified by a PD controller with continuous linear feedback loops. Meanwhile, the influence of different values of the flexible joints stiffness coefficient for system stability is taken into analysis and comparison. The results of simulation analysis show that when the stiffness coefficient is small, flexible variable of the joints is big, which is very adverse to the stability of the system. On the contrary, when the stiffness coefficient is bigger, flexible variable of the joints is smaller which is more conducive to control the system.