Research On Design And Wrapping Grasping Of Continuum Manipulators With Variable Cross-section

With the increasing number of spacecraft in space,a part of the scrapped or damaged space vehicles produce a lot of space junk.Because the traditional rigid manipulator performs the grasping task through the special end-effector,it has poor versatility and is difficult to accomplish the grasping of non-cooperative targets.In this paper,a kind of continuum manipulator for space dexterous operation is developed,which has the advantage of light structure,and the variable cross-section design is adopted to further improve the dexterity of the manipulator,and it can even perform wrapping grasping,which is more suitable for all kinds of operations in unstructured environment.The kinematic-static coupling model of the continuum manipulator is established,which more accurately describes the profile of the continuum manipulator under the driving force,and proposes to use the interval analysis algorithm to solve the model,which can calculate all the solutions within the specified solution range.The solution results of interval analysis are compared with the optimization algorithm,and the two are mutually verified.Then the principle prototype of the plane configuration is made for experimental verification.Using the kinematic-static coupling model,the load capacity of different variable cross-section configurations is analyzed,the configuration with high load capacity is selected,and the variable cross-section parameters of the central backbone of the configuration and the variable cross-section parameters of the supporting plate are optimized to improve the bending and wrapping ability of the continuum manipulator.Among them,it is necessary to avoid the collision of the continuum manipulator's own structure during the wrapping simulation process,so an improved GJK algorithm is proposed to detect the self-collision of the continuum units.After determining the variable cross-section parameters,design the structure of the robotic arm,improve the connection between the supporting plate and the backbone to increase the structural strength,and select and design the rope and the rope hole to reduce the friction,and then analyze the workspace for the variable cross-section continuum manipulator.By calculating the inverse solution of the kinematic-static coupling model,the offline trajectory planning of the variable cross-section continuum manipulator is realized,and the pseudo-rigid body model of the continuum manipulator is established,and the real-time problem of trajectory planning is solved based on differential kinematics.On this basis,combined with the rope length decoupling formula,a method for wrapping and grasping of a continuous manipulator with variable cross-section is proposed.The wrapping ability of the manipulator is analyzed,and the wrapping and grasping process is simulated with a sphere as an example.The prototype integration of the variable cross-section continuum manipulator was completed,and the space trajectory accuracy test and the wrapping and grasping experiment of the manipulator were carried out to verify the theoretical model,variable cross-section design,trajectory planning algorithm,wrapping and grasping method and other contents proposed in this paper for the variable cross-section continuum manipulator.