Water ship trajectory tracking control method for actuator asymmetric saturation

Abstract

The invention relates to a water ship trajectory tracking control method for actuator asymmetric saturation. The method comprises steps: 1, an expected tracking trajectory is given, an expected plane position (x<d>, y<d>) is given, an expected yaw angle psi<d> is given, and the expected trajectory is presented to be eta<d>=[ x<d>, y<d>, psi<d>]<T>; 2, a trajectory tracking error is calculated, and the error, z1=eta - eta<d>, between the actual trajectory and the expected trajectory is calculated; 3, an expected speed is calculated, and the expected speed alpha needed for eliminating the error between the expected trajectory and the actual trajectory is calculated; 4, a neural network is designed, an uncertainty delta in a kinetic equation uses the neural network delta=W<*T> phi(theta) + epsilon to be approximately expressed; 5, an auxiliary control system is designed, a Gauss error function is used, and a smooth asymmetric saturation actuator model is designed; and 6, a model control law is calculated, a control quantity tau needed for eliminating the error between the expected trajectory and the actual trajectory is calculated. The method can approximate a model uncertainty, suppress external disturbance influences, resist asymmetric saturation of an actuating mechanism, track any expected trajectory and ensure gradual stability of the system.

Description

technical field [0001] The invention provides a trajectory tracking control method of a surface ship with asymmetric saturated actuators. It provides an unmanned surface ship with actuators with asymmetric saturated nonlinear characteristics, which can suppress the influence of external disturbances and track the desired trajectory. The new control method belongs to the technical field of automatic control. Background technique [0002] An unmanned surface vessel is a vessel with robotic technology that can respond to changes in its environment and complete its mission with minimal human intervention. And it is widely used in navigation, intelligent surveillance and reconnaissance tasks, and is of great help to surveying, scientific research, search and rescue. Therefore, we need to design a controller with high performance trajectory tracking capability for unmanned surface ships, so as to realize accurate reference trajectory or virtual objects of surface ships. However,...

AI Technical Summary

Problems solved by technology

However, in the process of tracking control of surface ships, the dynamic model itself has certain uncertainties, the existing actuator saturation problem, or strong ocean disturbances will lead to system instability.

In addition, in the previous studies, the actuator saturation was assumed to be symmetrical. However, when the surface ship implements the forward trajectory tracking task, its thrusters only output positive force, or when the effectiveness of the actuator is partially lost, Asymmetrical saturation occurs

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