Design and analysis of n(3-RRU) deployable and reconfigurable serial-parallel manipulator for on-orbit manipulation and capture

Abstract

The advancement of on-orbit manipulation and capture capabilities is crucial for various aspects of space exploration and utilization, demanding a broader operational range, the handling of larger manipulation loads, and higher deployable/foldable during manipulation and capture. However, Traditional space robotic systems inevitably encounter the issue of substantial increases in both volume and weight to extend their operational envelope while preserving rigidity and precision. It is an urgent challenge to develop novel lightweight, high deployable/foldable ratio and reconfigurable space robotic systems. In this study, we propose a novel n(3-RRU) deployable and reconfigurable serial-parallel manipulator (DRSPM) that can be folded into a compact configuration for convenient transportation and reconfigured into a deployable configuration for achieving on-orbit large-range and high-precision manipulation and capture. Firstly, we propose a novel 3-RRU reconfigurable parallel mechanism (RPM) with bifurcated motions. The actuation arrangement of 3-RRU RPM is constructed using one motor and two springs, allowing it to exhibit single-degree-of-freedom controllable deploying motion and then switches to controllable bending motion through only one motor control, which can effectively reduce the complexity of the control system and the weight of the drive structure. The mobility, singularities, forward and inverse position solutions, and the motion trajectory of the 3-RRU RPM are analyzed and further validated through ADAMS simulations and prototype. Furthermore, we analyze the actuation arrangement and workspace of 2(3-RRU) DRSPM and 3(3-RRU) DRSPM, showing that serially connecting multiple 3-RRU RPM units significantly enlarges the workspace of the n(3-RRU) DRSPM. We fabricate prototypes of 3-RRU RPM unit and 3(3-RRU) DRSPM based on the theoretical design, where the deployable-to-foldable ratios for 3-RRU RPM unit and 3(3-RRU) DRSPM are 3.5 and 3.7, respectively. The maximum rotational angle for 3-RRU RPM unit is 37°. This indicates that the n(3-RRU) DRSPM exhibits a significant deployable-to-foldable ratio and operational workspace. Precise control of the bending motions of each 3-RRU RPM unit enables the n(3-RRU) DRSPM to achieve large-range and high-precision on-orbit manipulation and capture.