Design And Research Of Robot Orbit Assembly Scheme For Large Space Parabolic Structure

The competition for space in the world is becoming fiercer,and the demand for largescale space structures is becoming more and more urgent.Adopting the traditional unfolding structure will greatly increase the complexity of the mechanism and reduce the reliability of the system,and it needs a larger thrust and size launch vehicle.On-orbit assembly can be constructed by robots or astronauts in space to build a larger space structure,thus breaking through the limitations of rocket size and thrust.At present,in orbit assembly schemes,there are shortcomings such as astronauts ’out-of-warehouse activities,low stiffness of tandem robots,complicated reflective surface adjustment mechanism,and excessive volume of end effectors,which are not conducive to the assembly of large-caliber space structures above 50 meters.Aiming at the above problems,this paper proposes an on-orbit assembly solution for robots with large space parabolic structures.The main research contents are as follows:1.Aiming at the problem that the truss structure is too large and heavy in on-rail assembly,a modular assembly scheme without unfolding truss is proposed.Firstly,a parabolic spiral curve is generated based on Fermat spiral,and a lattice is generated based on the golden angle of sunflower;the assembly module is generated using the lattice,and then the shape of the triangular module is optimized,so that there are few types of splicing modules,which is easy for engineering practice;Structural robot assembly plan.2.Aiming at the shortcomings such as low rigidity of tandem manipulator,a climbing hybrid on-rail assembly robot is designed.First,analyze the freedom of the hybrid robot based on the spiral theory;analyze the kinematics inverse solution based on the vector method and establish a virtual model with MATLAB and ADAMS to complete the simulation verification;derive the Jacobian matrix of the mechanism;design the joint transmission mode of the robot,and finally Perform static analysis and modal analysis on the main parts.3.Aiming at the problem of complicated kinematic coupling of the traditional parabolic reflective surface adjustment mechanism,a 3-branch parallel fine adjustment mechanism with less reflective surface is proposed.First,its degree of freedom was analyzed based on the spiral theory;then its inverse kinematics solution was analyzed,and a very concise approximation algorithm was proposed for engineering practice and combined with the ADAMS model for simulation verification;then its positive kinematics solution was analyzed.For nonlinear equations Using the Newton iteration method,a numerical algorithm that is easy for engineering practice is written,and combined with MATLAB and ADAMS for simulation verification.4.Aiming at the shortcomings of traditional space robot end effector,such as complex structure,large volume and inflexible use,design a small volume adaptive end effector based on magnetic force.Firstly,the main structure of the end effector is designed based on the principle of magnetism,and secondly,the combined design of the telecommunication interface is carried out,so that the end effector can meet the requirements of different on-rail assembly tasks.Then use Maxwell software to establish a magnetic simulation model,perform magnetic simulation at different docking distances,and obtain the magnetic curve of the passive end.Then,an ADAMS virtual model is established,and the entire docking process is simulated and analyzed to verify the end effector’s performance.Tolerance and self-adaptive characteristics;Finally,an endeffector connection force experiment was conducted to verify the large connection force characteristics of the actuator.5.Build a simulation experiment platform and design a ground experiment platform.Firstly,ADAMS was used to build a simulation experiment platform for onorbit assembly of hybrid robots,and a 6-module simulation assembly experiment was successfully carried out.The additional torque generated is small,which is conducive to large-scale on-rail assembly experiments and verifies the correctness of the on-rail assembly scheme design.In addition,the design of the ground experimental platform was carried out,including the design of the main task management platform,the design of the joint motor debugging platform and the design of the ground experimental tooling.