Abstract

With the release of Bombardier's new vertical take-off and landing unmanned air vehicle (VTOL UAV), the company's design team were interested in exploring new ideas for automatically landing the craft. Bombardier established guidelines and limitations on performance in order to ensure the safety of the craft and those individuals in its operating region. The cornerstone of the design revolved around navigation via DGPS data. Three issues were identified as being paramount to the success of the system. First was the need for an algorithm to locate an appropriate intercept point on the intended flight profile after a position error is found after navigation system switchover from waypoint mode, using GPS, to the more precise autoland mode, which uses DGPS. With the establishment of concrete target points, a corroborative effort between two systems was required to command vehicle motion between two arbitrary points in space. The first system, a trajectory generator, provides an ideal locus of points based on a time law, paying careful attention to the craft's acceleration. The second system involved a controller using the ideal points generated by the trajectory generator to drive the craft. An easily obtainable solution for the controller was required given project scope. The evaluation tool for theory development was a simplified version of Bombardier's overall craft dynamics model for the CL-327