Modelling and identification of a twin hull-based autonomous surface craft

Abstract

In this paper, the process and results of a parameter identification task for a maritime unmanned surface vehicle are presented. The system has been modeled using state of the art methodology, and the parameters have been estimated via a weighted least square optimization approach. The required measurement data have been taken from various maneuvre trials. For solving the optimization problem, a Particle Swarm programming approach has been used, which has reliably found the global minimum of the cost function. The results show excellent agreement between measured and simulated data.

Optimal control allocation for an ASC with two azimuth-like thrusters with limited panning range

“…The required generalized control forces (Fig. 12(a)) in order to make the ASC follow the desired trajectory are generated using the inverse of the vessel model [15]. The corresponding control variables using the original and the modified cost function are illustrated in Fig.…”

“…F i > 0 denotes forward thrust, whereas F i < 0 is attained by changing the rotational direction of the propeller in order to produce reverse thrust. The force magnitudes are estimated using a model-based approach as presented in [15]. This approach defines a simplified propeller model to determine the thrust force acting along the propeller axis, depending on the propeller rotational speed and the speed of advance.…”

“…This can be seen in Fig. 6, which exemplarily shows the value of the portside azimuth angle α 1 indicated by the color as a result of the optimization using (15). For illustration purposes F res = 1 N is kept constant, whereas φ and τ cψ are varied.…”

“…Each of the combinations requires certain force magnitudes F 1 , F 2 . By weighting the force magnitudes with an exponent m > 1, as in (15), the larger force is penalized more severely. Thus, the optimizer tries to decrease the larger force at the cost of the smaller one.…”

Robust Control and Fuzzy Logic Guidance for an Unmanned Surface Vehicle

“…The DELFIM has integrated guidance, navigation and control to carry out straightforward its tasks. In [3], the CaRoLime USV presents integration between electronic hardware in order to execute missions for limnology studies in ocean and rivers. The paper also presents a mathematical model obtained using system identification approach and least square estimation optimization.…”