Performance Analysis And Simulation Research Of Space Mobile Robot Based On Hybrid Mechanism

The urgent demand for large-span parabolic antennas,large-scale optical systems and other large-span and large-area space structures in future-oriented strategic reconnaissance,astronomical observations,and deep-space communications has made the on-orbit assembly technology a hot topic among aerospace giants,and the use of robotics for on-orbit assembly is an important research direction.Based on this,this paper has carried out the study of the hybrid mechanism with the integration of mobile and assembly functions,and constructed a space-movable R+2SPS/RRPRR+R three-branch hybrid mechanism,which not only has a high rigidity,compact structure,simple inverse kinematics and good dynamic performance,but also has the characteristics that can achieve high precision,high efficiency large-area plate splicing.This paper conducted an in-depth study to it,and the main contents are as follows:1.Kinematics modeling and analysis of the hybrid mechanism are performed.Firstly,the configuration and working method of the mechanism are described.The degree of freedom of the mechanism is analyzed and verified using the screw theory,then the inverse kinematics equation of mechanism is deduced using DH method and vector analysis method.On this basis,the differential transformation method is used to theoretically deduce the speed and acceleration of the mechanism,then the virtual parameterized model of the mechanism is established in ADAMS,and the multiple positions motion of the mechanism is analyzed by ADAMS.Comparing with MATLAB data,the correctness of the theoretical analysis is verified,and the quasi-Newton method is used to iteratively calculate and verify the positive solution of the mechanism.2.Work space and singularity analysis are performed on the hybrid mechanism.Firstly,the factors that affect the working space are analyzed,and then the limit boundary search algorithm is used to describe the steps of the solution,and the dexterous workspace is visualized by MATLAB.On this basis,the single variable method was used to quantitatively analyze the influence of the structural parameters of the hybrid mechanism on its workspace,and the optimal structural parameters are obtained according to the requirement of the splicing task.Then,the singularity of the mechanism was analyzed by the screw theory,and the singularity location is found out and the degree of freedom is analyzed during movement.And a solution is proposed to avoid singular points by setting the threshold of the Jacobian.3.The static and dynamic and simulation analysis of the hybrid mechanism is carried out.Firstly,the method of establishing the dynamic model of the parallel mechanism is introduced,and the static and dynamic theory of the R+2SPS/RRPRR+R hybrid mechanism is derived by virtual work.Then using the reciprocal characteristics of the velocity Jacobian matrix and the force Jacobian matrix,the mapping relationship between the end force of the mechanism and the joint driving force is established.Then based on assembly model of PRO/E,the dynamic performance of the hybrid mechanism under two specific trajectory conditions was simulated and analyzed in ADAMS,which provided a theoretical basis for motor selection,mechanism optimization design and dynamic control.4.The trajectory planning is conducted on the hybrid mechanism.Firstly,the general methods of trajectory planning are analyzed.The theoretical analysis of joint space and Cartesian space trajectory planning is carried out by cubic spline curve and equivalent shaft and angle method,and the real time motion of the mechanism is simulated in joint space,Cartesian space and multi-transition points by co-simulation of MATLAB and ADAMS.Smooth and no mutation of the planned trajectory curve are verified,which would not cause large impact on the drive joints.It laid a theoretical foundation for follow-up mechanism trajectory optimization and control strategy research.Through the above work,this paper established a mathematical model of the R+2SPS/RRPRR+R hybrid mechanism,verified the feasibility of the key technologies of the hybrid mechanism,realized the integration of mobile and assembly functions,and achieved task requirements of high precision and high efficiency large-area plate splicing.