Space Experiment for a Tethered Space Robot by Kagawa University

Abstract

This paper describes the two kinds of space verification experiments for a tethered space robot. A tethered space robot is a new type of space robot system proposed in the previous work. The major advantage is that its attitude can be controlled under tether tension by its own link motion. One space experiment was done by a pico-satellite named “KUKAI” on the orbit (Altitude: 666 km, Inclination: 98 deg). Basic function of the tether tension control system was verified, though tether could not be extended enough. Also, the mother (4.2 kg) and the daughter satellites (3.8 kg) were separated away for several centimeters, and then, basic robot motion and sensor based feedback control were verified. The other space experiment was done by the sounding rocket S-520-25. It has a capability for launching far above 300 km altitude and provides more than 5 minutes for space flight environments. The tether was extended (more than 2 m) and kept its tension, and the attitude control of the robot (2.2 kg) was performed. The disturbed vibration of attitude was suppressed, and also it was converged on the desired attitude by arm link motion control of the robot.