Reactionless path planning for a satellite-mounted manipulator intercepting a moving target

Manipulators, working in space, execute a wide range of tasks, such as loading or un- loading, servicing, and assembly operations. Motion of the manipulator, mounted on a free-flying satellite, creates the reaction forces and moments, which, transmitted to the base, alter its position and orientation. The Reaction Null-Space (RNS) manipula- tor path planning algorithm, which ensures reactionless manipulator motion, has been chosen to develop a trajectory for a planar satellite-mounted three-link manipulator intercepting a target. Three cases of manipulator motion, subject to different con- straints, have been studied: (1) constraints on the joint acceleration and reaction force norms at the point of interception, (2) constraints on joint accelerations at the inter- ception point, and (3) minimum joint acceleration along the whole trajectory. Three reactionless path planning algorithms corresponding to the above constraint scenarios have been implemented in MatLab. The absence of base rotational disturbances has been verified by simulating the base-manipulator system with the reactionless joint motions using MSC Adams software.Les manipulateurs, mobiles dans l'espace, r ́ealisent une large gamme de taˆches telles que le chargement ou d ́echargement, l'assemblage ou encore les services. Le mou- vement d'un manipulateur mont ́e sur un satellite cr ́e ́e une force et un moment de r ́eactions qui, transmis `a la base du satellite, en modifient la position et l'orientation. Assurant un mouvement du bras sans r ́eaction sur la base, l'algorithme de trajectoire du manipulateur Reaction Null-Space (RNS) a ́et ́e choisi pour d ́eterminer la trajec- toire d'un manipulateur tri-segment plan mont ́e sur satellite et destin ́e `a l'interception d'objets. Trois cas de mouvements, soumis `a diff ́erentes contraintes, ont ́et ́e ́etudi ́es: (1) contraintes sur les normes de l'acc ́el ́eration de l'articulation et de la force de r ́eaction au point d'interception, (2) contraintes sur l'acc ́el ́eration de l'articulation au point d'interception, et (3) minimum de l'acc ́el ́eration moyenne de l'articulation tout au long de la trajectoire. Trois algorithmes de mouvement sans r ́eaction correspon- dants aux trois cas pr ́ecit ́es ont ́et ́e cod ́es sous MatLab. L'absence de perturbation de l'orientation de la base a ́et ́e v ́erifi ́ee en simulant, `a l'aide du logiciel MSC Adams, le syst ́eme compos ́e de la base et du bras lors d'un mouvement de l'articulation