The Adaptive Dynamic Visual Servoing Of The Free-floating Space Manipulator

Space manipulators are widely used in OOS(On-orbit Servicing)such as parking,handling,maintenance and obstacle removal.The free-floating space manipulator is composed of an uncontrolled base and a controlled robot arm with respect to the free-flying space manipulator.Free-flying robotic arm control base requires expensive fuel consumption,while in free-floating case uncontrolled base saves fuel costs,increased satellite operating time,and broadened application prospects.As a method of controlling robot motion using visual information from the camera,visual servoing can make full use of the rich information of vision to complete the traditional control task with low system complexity and cost.It is an ideal method as a manipulator control scheme in complex environments.For the space robot,the visual servo can use the camera to detect the tracked object,the error defined in the image plane,which is free from the measurement of the end-effector position,which will complete the space mission better.In this paper,we study the tracking of target visual characteristics under the hand-eye configuration of free-floating space manipulator during space-orbit service acquisition.In order to estimate the motion of the target and the depth information of the feature point,the depth independent visual Jacobi matrix is deducted and the Jacobi matrix is designed based on the depth independent visual Jacobi matrix is under the assumption that the motion of the tracked object is unknown and the dynamic parameters of the system are uncertain.The target feature point motion estimator is designed.A dynamic adaptive controller is designed to control the motion of a free-floating manipulator.The dynamic parameters are estimated and the error of the feature points is converged to zero.In this paper,the Lyapunov method is used to prove the stability of the system and the asymptotic convergence of image errors is proved.The simulation results show the effectiveness of the proposed controller in a planar manipulator and a 6-DOF three-dimensional manipulator.The main innovations of this paper are as follows:1.The depth independent matrix of the space manipulator is deducted,and the target feature point motion estimator is designed based on the depth independent matrix.2.The kinetic equation of the manipulator is deducted to overcome the difficulty of the linearization of the classical dynamic equation,and a dynamic adaptive controller is designed.3.Combined with the traditional dynamic adaptive control scheme and the depth independent matrix visual servoing scheme,a visual adaptive controller is designed to prove the stability of the system.4.Due to the high complexity of the dynamic equations of the high-DOF free-floating space manipulator,it is difficult to derive the analytical expression.The recursive visual adaptive control based on the space vector method is used to calculate the input torque.Simulation results show that the control effect.