Autonomous Assembly of Cellular Satellite by Robot for Sustainable Space System

Paper number

IAC-05-D1.2.04

Author

Mr. Hideyuki Tanaka, University of Tokyo, Japan

Coauthor

Dr. Kazuo Machida, University of Tokyo, Japan

Coauthor

Dr. Takehisa Yairi, University of Tokyo, Japan

Coauthor

Mr. Noritaka Yamamoto, University of Tokyo, Japan

Year

2005

Abstract

"Sustainable development" is required for the future space system. One idea to achieve this concept is to make space infrastructures reusable and reconfigurable.\\
We developed a prototype of the Cellular Satellite (CellSat) for such a reconfigurable space system. The CellSat is a new concept of satellite which is the advanced version of modular satellites. It is composed of multiple cells corresponding to various missions, and is able to be assembled and reconfigured by a space robot on orbit.\\
The purpose of this research is to develop the assembly technology of the CellSat by an autonomous robot, and to verify it through the experiments. Since the assembly requires high skill, there are few researches for such applications in the field of space engineering.\\
This technology expands the utilization of the CellSat system itself, and contributes to the realization of one of the future space systems. In addition, it improves the basic ability of autonomous robots in assembly, because the precise control technique developed is widely applicable to many kinds of assembly tasks in space.\\
In this paper, we first describe the CellSat which we designed. The "cells" of the CellSat are 60mm-cubic shape and they are the components of satellites such as battery, CPU, sensor, thruster, and so on. Using space robots, we can connect these cells on orbit and assemble many kinds of small satellites. They also enable the partial replacement and reconfiguration. Therefore, the maintenance such as refuel, repair, and the hardware update is possible on orbit. The cells are designed to have robot-friendliness structurally and visually so as to be easily handled by the robots.\\
Next, we describe the assembly technology of CellSat by the robot. The connection/disconnection of two cells is performed by insertion and rotation of a connector-pin handled by small end-effectors of the robotic manipulator. Because the task includes complicated contact relations between small devices, the robot must have delicate control technique, so called the “skills”. At the same time, it must have the robustness which overcomes the little misalignments of hardware and uncertainty of environment in the real world. We achieve the skill acquisition by using the method of machine learning. The robot acquires the assembly skills by learning the relations between the states of the objects, actions of actuators, and the reaction data of the object. It is expected to realize the precise and robust control technique for the assembly task.\\
We verify this technology through the assembly experiments. The robot collects the learning data using the real hardware, and acquires the assembly skills, then connects three cells applying the skills. We show the experimental results and evaluate them.

Abstract document

IAC-05-D1.2.04.pdf

Manuscript document

IAC-05-D1.2.04.pdf (🔒 authorized access only).

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