Preset-Trajectory-Based Tracking Control of a Class of Mismatched Uncertain Systems

Existing function augmented sliding mode control approaches based on preset trajectories are applicable only to matched uncertain systems. In this article, two preset-trajectory-based tracking control methods are proposed for a class of mismatched uncertain systems utilizing the backstepping method. The first method is the preset-trajectory-based practical prescribed-time tracking control method, which can guarantee that the output tracking error converges to a prescribed zone in a prescribed time. The second method is the preset-trajectory-based preassigned performance control method, which, in addition to guaranteeing that the output tracking error can be confined within the prescribed performance envelope, is free from the singularity problem of the control law, a problem that may appear in the existing prescribed performance control methods under some unexpected situations (e.g., sensor faults). The effectiveness of both proposed control methods is illustrated through a simulation example on the roll control of bank-to-turn missiles.