Online Trajectory Generation for Space Manipulator via Nonlinear Model Predictive Control

In this paper, a novel online trajectory planning strategy for a satellite equipped with a robotic arm is presented. This problem is tackled using a nonlinear model predictive control approach, and the result is a flexible trajectory generation strategy that is able to adapt in real time to unseen scenarios and time-varying mission objectives. First, the kinematic and dynamic equations of the system are derived with particular attention with respect to representation singularities and computational efficiency. Then, the trajectory generation problem is written in the form of a constrained optimization problem taking into account actuators saturation and potential collisions with itself and the target object to be grasped. In the last part, multiple simulation scenarios are analyzed to verify the performance and effectiveness of the proposed solution.