Improved LOS Guidance Law for Path Following of Underactuated USV with Sideslip Compensation

Abstract

In this paper, we present an improved line-ofsight guidance law (LOS) for path following of underactuated unmanned surface vehicles. In the proposed approach, the sideslip angle is treated as an unknown system state that is estimated simultaneously with the cross-track error using an augmented extended Kalman filter (AEKF). Simulation results demonstrate that the proposed guidance law exhibits faster convergence and better path following performance compared to the available LOS methods.

KF-based LOS Guidance Law for Path Following of USV: Experiments and Performance Evaluation

“…(4) By taking the time derivative of (4) and performing some algebraic manipulations, the dynamics of the cross-track error can be expressed as [5]: (5) where U = √ u 2 + v 2 is the total speed and β = atan2(υ, u) is the sideslip angle. The control objective is to ensure that lim t→∞ y e (t) = 0, which can be achieved by defining the appropriate guidance law ψ d (the desired heading angle).…”

“…The augmented state vector can be estimated by using the Extended Kalman filter (EKF), as proposed in [5]. The update equation has the following form ξ = f ( ξ) + K(y e − ŷe ),…”

“…This is achieved by treating the sideslip angle as an unknown system state and then utilizing an augmented extended Kalman filter (AEKF). The Kalman filterbased (KF-based) LOS guidance law results in faster convergence speed and improved path-following performance, as demonstrated through numerical simulations in [5].…”

“…To successfully execute these motion scenarios, it is crucial to properly design the kinematic guidance law and the heading controller. Within the guidance loop, common methods encompass line-of-sight (LOS) [3]- [5] and constant bearing guidance [6]. Meanwhile, in the heading control loop, widely employed techniques include fuzzy controller [6], PID controller [7], adaptive controller [8], neural network controller [9], sliding-mode controller [10] and modelpredictive controller [11].…”

“…Notably, among these, predictor-based methods have proven to be the most effective in terms of performance. In a recent publication [5], the authors have introduced a novel LOS guidance law for the path following of USVs with sideslip compensation. Unlike existing predictor-based approaches that use independent adaptive gains for updating the crosstrack error and sideslip angle estimations, the proposed method simultaneously estimates the sideslip angle and the cross-track error.…”