Research On Intelligent Control Algorithms For A Space Robot With The Elastic Base And Elastic Joints

With the development of social civilization and the rapid progress of science and technology,human activities on exploring and building space become more and more frequent.As important assistants,space robots have been playing an important role in the construction and exploration of space.At present,more and more aerospace powers and well-known commercial companies are engaged in the development of space robots.To meet the requirements of future space operations,more and more space robots have been developed and applied in various workplaces.Besides,to reduce the launch cost,space robots become light-weight which is a major trend in the development of space technology.However,it is worth mentioning that the utilization of various light composite materials and joint harmonic flexible wheels in robots can reduce the weight of the system,but it is prone to induce the elastic vibration of main components of the system(such as the base,joints,etc.)in the working process.It is thus obvious that solving the system dynamics control problems under the effects of elastic deformation of the base and joints has practical significance for improving the working efficiency and the operating accuracy of space robots.Therefore,the intelligent control algorithms for a space robot with the elastic base and elastic joints are studied in the paper.Firstly,based on the linear spring model descriptions on the elastic deformation of the base and joints,the momentum conservation principle and the second Lagrangian modeling method,the dynamic equations of a space robot with the elastic base and elastic joints are established.Using the singular perturbation theory,the singular perturbation decoupling operation is carried out,and the fast and slow subsystems with two time scales are obtained.Then,based on the fast and slow subsystems mentioned above,an adaptive control and elastic vibration suppression scheme based on the principle of non-certainty equivalence is designed for the system with unknown inertia parameters by introducing a new filter and redefining the system parameter regression matrix.A kind of adaptive fuzzy control and elastic vibration suppression scheme for the coordinated motion and the end-effector motion of the system with unknown inertia parameters and external disturbances is designed.To improve the real-time performance of the adaptive fuzzy control system,a new adaptive fuzzy control and elastic vibration suppression scheme is proposed.In this scheme,the ideal control input of the system is directly approximated by an adaptive fuzzy system,so that the space robot can track the desired coordinated trajectories under the complex working conditions.Besides,an error-performance-function-based adaptive fuzzy control and elastic vibration suppression scheme is designed for the system with unknown inertia parameters,external disturbances and error performance requirements.The control scheme can realize the high precision trajectory tracking of the base's attitude and the manipulator's joints.Finally,some numerical simulation experiments are carried out to verify the effectiveness of the proposed control schemes.