Three-Dimensional Space-and-Time-Synchronized Target-Tracking Control Under Input Saturation

In this article, we present a space-and-time synchronized control method for target-tracking problems under input saturation in the three-dimensional (3-D) framework of polar coordinates. We first utilize the prescribed-distance controller to design a reference relative trajectory, aiming to formulate a synchronization of space and time. By doing this, the specified position can be approached at its predetermined instant and the relative trajectory in space is independent of time. Next, through correlating and decoupling the reference/actual kinematics between the self vehicle and the target, time and space are separated, controlled independently. To further address the existing closed-loop system errors, we propose a dynamic velocity assignment of the relative reference trajectory, which is an independent extra degree of freedom, to alleviate the negative effects caused by input saturation. Finally, numerical simulations are provided to demonstrate the effectiveness and superiority of the proposed scheme.