Contents lists available at ScienceDirect Acta Astronautica journal homepage: www.elsevier.com/locate/actaastro Attitude dynamics and control of a spacecraft like a robotic manipulator when implementing on-orbit servicing Ijar M. Da Fonseca a, ⁎ , Luiz C.S. Goes a , Narumi Seito a , Mayara K. da Silva Duarte a , Élcio Jeronimo de Oliveira b a ITA/Aeronautical Mechanics Division, São José dos Campos, SP, Brazil b DCTA/IAE, Department Aerodynamics, São José dos Campos, SP, Brazil ARTICLE INFO Keywords: Space robotic manipulator Attitude control Relative motion Docking/berthing ABSTRACT In space the manipulators working space is characterized by the microgravity environment. In this environment the spacecraft floats and its rotational/translational motion may be excited by any internal and external disturbances. The complete system, i.e., the spacecraft and the associated robotic manipulator, floats and is sensitive to any reaction force and torque related to the manipulator's operation. In this sense the effort done by the robot may result in torque about the system center of mass and also in forces changing its translational motion. This paper analyzes the impact of the robot manipulator dynamics on the attitude motion and the associated control effort to keep the attitude stable during the manipulator's operation. The dynamics analysis is performed in the close proximity phase of rendezvous docking/berthing operation. In such scenario the linear system equations for the translation and attitude relative motions are appropriate. The computer simulations are implemented for the relative translational and rotational motion. The equations of motion have been simulated through computer by using the MatLab software. The LQR and the PID control laws are used for linear and nonlinear control, respectively, aiming to keep the attitude stable while the robot is in and out of service. The gravity-gradient and the residual magnetic torque are considered as external disturbances. The control efforts are analyzed for the manipulator in and out of service. The control laws allow the system stabilization and good performance when the manipulator is in service. 1. Introduction The first rendezvous and docking between two spacecraft took place on March 16, 1966. At that time Neil Armstrong and Dave Scott performed a rendezvous manually in a Gemini vehicle. Since then the operation has been used in several space missions. As the space environment is dangerous for human being, the applied research and design for space Rendezvous docking/berthing took the direction of autonomous robotic operations. Early in the space conquer the soviets invested on automation for space operation and in October 1967 the Soviet vehicle Cosmos 186 and 188 docked. Only later on the 1998 decade the ETS VII implemented and demonstrated successfully an on-orbit experiment for docking operation. ETS is an acronym that stands for Engineering Test Satellite. The concept, development and implementation were done by the Japanese at the former Japan NASDA space agency, renamed to JAXA. The overall mission objectives were to conduct space robotic experiments and to demonstrate its utility for unmanned orbital operation and servicing tasks (rendezvous-docking techniques). In the rendezvous-docking experiment, the chaser satellite conducts rendezvous-docking with the target satellite by both automatic and remotely piloted controls, and in the space robotic experiments, unmanned space work is carried out by teleoperation. The autonomous target capture by an unmanned space robot is a big challenge for the space robotics community. The Japanese experiment comprised two satellites: the chaser and the target space vehicles. During the RVD operation the chaser released the target and drift away to about 9 km far. Then a maneuver carried the chaser back to the target to accomplish the docking. The chaser spacecraft was equipped with robotic platform which the assessment to the employed technologies used for i) the teleoperation taking into account the time-delayed and limited-capacity telecommunication; ii) the coordination and control of the satellite and the robot manipulator; iii) the in-orbiting satellite servicing. Since then space agencies and researchers has been investing in technologies to develop autonomous http://dx.doi.org/10.1016/j.actaastro.2016.12.020 Received 24 February 2016; Accepted 16 December 2016 ⁎ Corresponding author. E-mail addresses: ijar@ita.br (I.M. Da Fonseca), goes@ita.br (L.C.S. Goes), seito@ita.br (N. Seito), mayarakissya@yahoo.com.br (M.K. da Silva Duarte), elcioejo7@gmail.com (É.J. de Oliveira). Acta Astronautica 137 (2017) 490–497 Available online 18 December 2016 0094-5765/ © 2017 IAA. Published by Elsevier Ltd. All rights reserved. MARK