An Improved Geometric Controller for Position Tracking of the Quadrotors

Abstract

The classical ‘Geometric Control (GC)’ of the quadrotors is susceptible to the 180° turnover singularity, which could result in a crash. To overcome the problem, an ‘Improved Geometric Control (IGC)’ is developed based on a proposed attitude extraction method. The controller is cascaded with a position loop and an attitude loop. The two loops are bridged by the method. It geometrically determines the desired attitude from the desired thrust direction. Attitude tilt-prioritizing can also be achieved by scarifying the yaw control. Unlike the GC with almost global stability, the IGC is proved to be globally asymptotically stable. Simulation comparisons demonstrate excellent performance even when the quadrotor confronts large initial attitude and position errors. The singular problem is thoroughly avoided.

Keywords

• Quadrotor
• improved geometric control
• position tracking