With the interaction between the space robot tip and the environment, the base’s position and orientation are disturbed leading to force and trajectory control complexity. Impedance control is a technique for force and trajectory control in a robotic system. This paper presents a strategy of impedance control in a multiple cooperative space robots pulling a flexible wire. First, the control strategy was developed for one degree of freedom multiple space robots. The developed control strategy was extended to two degree of freedom cooperative space robots. A flexible wire is pulled by a group of space robots with one degree of freedom and two degree of freedoms, respectively. In the impedance-based control strategy design, the process of modulating the robot tip impedance is a very significant feature. In this work, impedance control strategy between tip and environment is applied for pulling a wire by one degree of freedom and two degree of freedoms. Impedance depends on the gain compensation for passive degree of freedom dynamics. Simulation and the animation studies are carried out to validate the proposed control scheme. The results achieved are quite satisfactory and reveal that impedance controllers in a multiple cooperative space robots with one and two degree of freedoms can limit the interaction forces to a predefined value of 8 N. The bond graph modeling methodology is used in the dynamic system model for the generation of system equations.
WITHDRAWN: Trajectory control strategy of cathodes in blisk electrochemical machining
