| dc.description.abstract | Space proximity missions essentially need on the ground hardware in the loop
(HIL) testing of sensors, algorithms, and actuators. Such testing would surpass
that of software only simulations and would mature hardware and software to vastly
reduce risk of close proximity operations. Simulation of interaction dynamics in
proximity operations is very difficult. An active pendulum system can be used to
simulate these important contact dynamics. The pendulum system can be commanded
to track trajectories which represent plausible contact dynamic motions.
The pendulum system can also be used to investigate unknown contact dynamics.
With an external robot to simulate spacecraft motion, a payload on the gantry system
can be subjected to contact forces. The pendulum system actively moves the
payload to simulate planar space-like contact dynamics throughout and after the
interaction. This thesis develops high fidelity and first principle based controllers to
allow for simulation of both prescribed and unknown planar contact dynamics. A
linear quadratic integral controller is designed for trajectory tracking. This controller
is compared with a nonlinear trajectory tracking controller developed using partial
feedback linearization. To simulate unknown contact dynamics a controller is developed
using uncollocated partial feedback linearization. The three controllers are
analyzed and compared using several test cases in software simulation. The nonlinear
trajectory tracking controller is shown to outperform the linear controller. Simulation
results also indicate that the unknown contact dynamics controller outperforms
the trajectory tracking controllers in the neighborhood surrounding interactions. | en |
