Design and analysis of a coupled space capture gripper inspired by basket star

LI Shuxian; YU Yiyin; WANG Rugui

doi:10.16578/j.issn.1004.2539.2026.07.008

Abstract：[Objective]Aiming at the tracking and capturing challenges of non-cooperative space targets characterized by unpredictable motions and irregular geometries,which frequently cause rigid manipulators to slip,a novel biomimetic coupled space capture gripper featuring a large workspace,low requirement for relative positioning precision,and high modularity was developed based on the evolutionary predation enveloping strategy of the basket star.[Methods]Firstly,the finger structure was synthesized using a crossed four-bar linkage as the core modular cell with serially connected knuckles,into which a synchronized master-branch steering transmission scheme was embedded to execute coordinated single-actuation multi-joint linkage motions.Secondly,the spatial kinematics of a single finger were derived through the closed-loop vector loop-closure technique,and the multi-body coordinate transformations were solved via the Denavit-Hartenberg parameter method.Thirdly,singularity configurations inside and along the boundary of the operational zone were identified via the determinant of the system Jacobian matrix.Furthermore,the workspace boundaries under distinct structural designs were calculated using an analytical boundary-stitching methodology integrated with the Gauss area formulation.Finally,a physical prototype was fabricated utilizing photosensitive resin 3D printing and validated through macroscopic cage-enveloping grasping sweeps on an automated motor-driven evaluation platform.[Results]Kinematic evaluations and laboratory tests demonstrate that the single-actuator symmetric pushrod mechanism effectively governs the five-finger synchronized closure trajectories.The parameterized sweeps indicate that optimization of link proportions substantially expands the peripheral reachability boundaries.The fabricated prototype successfully accomplishes form-closed self-adaptive captures on both rigid irregular polyhedrons and complex soft targets,confirming the high reliability and control simplicity of the biomimetic layout for orbital maintenance and debris removal missions.