On Vibration Control Of Highly-Redundant Flexible Robot And Its Chaos

Highly-redundant flexible robot with extensive prospective applications is highly coupling and nonlinear with plenty of complex kinematic and dynamic behaviours. So, it's of significance to investigate the motion features of such robot to improve its working performance. In this thesis, the vibration control and singularity avoidance of highly-redundant flexible robot are studied from the self-motion point of view as follows.Firstly, based on the finite element and the Lagrange equation, dynamic equation of a highly-redundant flexible robot is modeled by taking the unit elastic deformation as the generalized coordinates.Secondly, a modified vibration control method is developed based on the relations between the arbitrary vector in the null space and the vibration of the end-effector. In the method, to minimize the mean value of the vibration peaks in one motion cycle is the optimized goal, and the cosine rule is adopted to design the arbitrary vector for the purpose of vibration suppression. The application of the method to the vibration control of a planar 6R and a planar 8R flexible robot shows its feasibility.Finally, the self-motion state of highly-redundant flexible robot is explored by using chaos theory. The numerical simulations by means of the chaotic recognition methods show that, the self-motion of a planar 6R flexible robot under the pseudoinverse control with PD controller is chaotic when the end-effector traces a closed-path repeatedly in the workspace. It is also found that, under the same conditions, the chaotic motion of a flexible robot is more obvious than that of a planar 6R rigid robot by comparing their largest Lyapunov exponents.The dynamic modeling, optimization and simulations in this thesis are conducted utilizing Matlab.