Pre- and post-grasping robot motion planning to capture and stabilize a tumbling/drifting free-floater with uncertain dynamics

This paper focuses on optimal and seamless guidance of robotic manipulators, in both pre- and post-grasp phases, to capture and stabilize a tumbling and drifting free-floating object. All dynamics parameters of the object are assumed to be unknown with the exception its mass and the trace of the inertia matrix. In the pre-grasping phase, an optimal trajectory is planned to intercept a grasping point on the target with zero relative velocity subject to acceleration limit and adequate target alignment while minimizing the fly time and/or distance. In the post-grasping phase, the manipulator damps out the targets´s angular and linear momentums as quickly as possible subject to the constraint that the magnitude of the exerted force and torque remain below their pre-specified values. The unknown parameters in addition to the relative linear and angular velocities of the target needed for the motion planning are estimated by a Kalman filter estimator. Finally, an end-to-end validation of the robotic operation for grasping and stabilizing a tumbling/drifting free-floating object using the proposed robot motion planning scheme is presented by combination of experimental and simulation results.