Nonlinear Optimal Control of Holonomic Indoor Airship

摘要

A full-state feedback controller is proposed to fulfill the requirements for flying an indoor holonomic airship. The airship is a custom-design spherical blimp actuated by 6 propellers in a symmetric arrangement. It is capable of general translational and rotational motion. A continuous tracker is designed to follow an arbitrary reference trajectory by employing the continuous version of the linear quadratic regulator (CLQR) in finite time. The controller is implemented and tested on the airship for tracking a rectangular trajectory in a laboratory setting. With little computation cost, the CLQR controller achieves significant improvement in terms of overshoot and attitude tracking error when compared to a standard proportional-derivative controller. To provide state information to the controller, an unscented Kalman filter is used to fuse information from a Vicon motion capture system and an on-board inertial measurement unit. The filter design is combined with the CLQR and this dynamic feedback controller is tested on the airship for the same rectangular trajectory. The use of sensor fusion and filtering leads to a significant reduction in actuator effort.