Research On Trajectory Tracking Control,Test And Flexible Force Control For Space Robot Manipulator

Wtith the development of science and technology,the curiosity about unknown universe has become increasingly stronger.In space activities,the space robot manipulator is an important tool for space station assembly,maintenance and repair,operation management,load care and in-orbit operation support.This paper focuses on the issues that the overall design and kinematics modeling,trajectory tracking control,technical index testing as well as flexible force control for the space robot manipulator,which provides engineering technical support for Chinese space robot manipulator.The main contents of this paper include the following aspects:Firstly,the overall design of space robot manipulator is carried out according to the task analysis.Modular symmetry design with 7-DOF configuration scheme is adopted in this paper,where each wrist has three degrees of freedom,the elbow has 1degree of freedom,and the end-effector is installed at each end of the arm.The two end-effectors are fixed on the target adapter to realize crawling function.Then,according to the configuration of space manipulator,the forward kinematics model is established based on Craig method.Considering the accuracy,speed and in-orbit stability,the inverse kinematics model is taken via fixing one joint and solving the solution with 6-DOF robot manipulator.Secondly,the trajectory tracking control of space robot manipulator is studied.High precision trajectory tracking control is the key link of space robot manipulator to successfully complete the space mission.Considering the model uncertainties and external disturbances of space robot manipulator,an adaptive backstepping sliding mode controller based on radial basis is designed in this paper.The validity of the algorithm is verified via numerical simulation.However,this algorithm is complex on engineering application,a linear adaptive disturbance rejection trajectory tracking control algorithm is proposed.The linear extended state observer can estimate the generalized disturbance effectively.Finally,the feasibility of the algorithm is proved by numerical simulations and space robot manipulator prototype experiments,which have certain engineering application value.Thirdly,the methods of the calibration test,accuracy test,speed test and acceleration test are proposed respectively for the assembled space engineering prototype.For the irregular end claw of robot manipulator,the hand claw coordinate establishing method based on the unique geometric shape is proposed.For the internal joint axis,the circumference of each joint is established based on the circumference fitting method.Then,the linear velocity,angular velocity,linear acceleration and angular acceleration at the end of the robot manipulator are tested by taking derivative and quadratic derivative of position and pose.Finally,the solution of the combination between API and triaxial is given for the problem of optical path occlusion in practical task.The index tests of the space robot manipulator verify the satisfaction of the overall design,which provides the strong guarantee for the preliminary processing,assembly results of single machine and whole machine,as well as the subsequent tests.Finally,a flexible force control ground demonstration system of space robot manipulator is constructed for the assembly of large caliber telescope as a typical task of space manipulator in orbit.A six-dimensional force/moment sensor and its data acquisition system are built.The least square method to compensate the gravity of robot is proposed.Then the flexible force control algorithm of the robot manipulator is designed.In combination with the end movement of the external load and the end rotation of the external load moment,the V-F curve and?-M_emaxmax curve are devised to control the movement and rotation of the robot manipulator.Eventually,the flexible force control ground demonstration experiments are carried out,and the flexible force control function of the robot manipulator is realized.It has the stable operation without jitter in the process of grabbing,transporting and assembling the whole sub-mirror module,which verifies the technical process and provides technical accumulation for the following in-orbit transportation and assembly tasks.