Contact Dynamics Modeling for Snare Wire Type of End Effector in Capture Operation

Abstract

It is essential to perform dynamic simulation in order to verify the safety of capture operation at time of contact between the grapple fixture of the H-II Transfer Vehicle (HTV) and the Latching End Effector (LEE) of the Space Station Remote Manipulator System. This paper presents the contact dynamics model for a snare wire inside the LEE in capturing the grapple fixture of the HTV. An explicit method for modeling contact dynamics is chosen so as to achieve a simple form and low computational cost in dynamic simulation. A contact model is developed using a rigid bar (grapple fixture) and a rigid wire. Wire stiffness is derived from the simplified equation of motion of the wire. The proposed stiffness model enables one to predict contact force during capture operation. Experimental measurement of the wire stiffness in static conditions verifies the proposed stiffness model. For the verification of the proposed model in dynamic conditions, a contact dynamics experiment is conducted using an air-floating test bed, which is capable of emulating two-dimensional planar micro-gravity environment. The experiment and corresponding dynamic simulation confirm the validity and usability of the proposed contact dynamics model.

The analysis of capture strategy for redundant space manipulator when performing snare capture

“…The physical properties of flexible cable cannot be reflected by this model, and the contact force is also treated as a force impulse. Uyama et al 16 divided the flexible cable into a number of beam elements, and adjacent beam elements were connected by three tensile springs and three torsion springs. The contact force was solved based on the classical Hertz contact theory.…”

“…So far, the dynamic behavior of the end-effector can be described by equation (16), and its inertial properties can be calculated by virtue of the positive definite matrixĤ. In the following, the inertial properties perceived at the end-effector are analyzed in terms of two types of tasks in operational space: the translational task and the rotational task.…”

Contact Dynamics Analysis for HTV Capturing by SSRMS

“…As an approach of the dynamics simulator, Ou Ma developed flexible SSRMS model and conducted a simulation in which SSRMS handles some payloads 7) . And Uyama, et al developed a model of snare wire and draw a comparison with experiment 8) . If we can predict a motion of HTV depending on the telemetry data from HTV and SSRMS in real operation time, it will be useful to assure safety of the mission.…”

Motion planning and control of cooperating robotic systems in orbit

“…This procedure includes tasks such as motion identification and matching, the actual docking and even de-tumbling of the passive object, whenever this is necessary. Studies in this field have provided several theoretical approaches and experimental facilities [3], [4], [5], [6], [16], [65], [78], [89], [102], [105], [115], [116], [118], [119], [120]. Besides the already mentioned past missions of ROTEX, ETS-VII, DART and Orbital Express, several architectures and autonomous docking missions are currently at various stages of development.…”