Ding Fuguang

AUV local path planning based on virtual potential field

We build a local path planning algorithm using virtual force for free local minimum. Potential field is used as a basic platform for the path planning since it has the advantages of simplicity, real-time computation. However, there is one shortcoming in the potential field: it may cause local minimum whenever the curvature of the repulsive equipotential curve is less than the curvature of the attractive equipotential curve at the same configuration. To get rid of the local minimum in the presence of obstacles, we present a navigation algorithm, which integrates virtual force concept with a potential-field-based method to maneuver autonomous underwater vehicle (AUV) in unknown or unstructured environments. This study focuses on the free local minimum in potential-field based navigation. We mainly consider the potential-field method in conjunction with virtual force concept as the basis of our navigation algorithm. Simulation and experiments of our algorithm shows good performance and ability to overcome the local minimum problem associated with potential field methods.

A GA path planner based on domain knowledge for AUV

Autonomous underwater vehicle (AUV) is extensively used for marine engineering, oceanography research and some other civil area. Path planning is a necessary and fundamental technology for AUV autonomy, its goal is to search an optimized path according to some optimization criteria in a certain environment and makes AUV fulfill its mission objectives along the collision-free path. Based on the theory and the application of GA, This work presents a global path planning method for AUV based on GA and domain knowledge in a large-scale chart. The grid method is adopted to set up a discrete space model for path planning based on known chart data, and each data structure of a grid stores some property such as digital elevation, permit and so on. A kind of decimal grid-coordinate coding scheme which adopting a variable length chromosome encoding is presented. The generating method of initial population, the fitness evaluation function, the evolve strategy and some superiority genetic operators are all designed and introduced in detail. And some measures are also adopted to improve the searching capability and to speed up convergence of the algorithm. The planning results show that the GA path planner has some advantages such as more stronger ability for searching a global optimized and viable path, efficiency superiority, convergence rapidly, path described more simply and perspicuous. The GA path planner based on domain knowledge becomes an important element of AUV autonomy ability and can be potentially applied as an on-line path planner for AUV.

A nonlinear estimate filter designed for ship dynamic positioning

A nonlinear estimate filter was designed for a dynamic positioning system. The global exponential stability of estimate filter was proven using Lyapunov methods. The main advantage of the nonlinear design to Kalman filter is that the kinematics equations of motion need not be linearized. The proposed estimate filter includes an estimation of both the low-frequency position and velocity of the ship from noisy position measurements, environmental disturbance and wave filtering. The simulation results show the excellent performance of the nonlinear estimate filter.

Study on stabilizing power of dynamic positioning ship based on thrust allocation

Thrust allocation is a necessary part of the dynamic positioning system, which sends control signals to the individual thruster. In this paper, an effective strategy for stabilizing power is proposed and an artificial fish swarm algorithm will be used. The stability of power on the ship can keep electric power system stable and make other functions work normally.

The ship capability calculation of a dynamic positioning system based on Genetic Algorithms

An optimization method base on Genetic Algorithms is used to calculate the control capability of the dynamic positioning system of a ship. Real number coding is used as the code of Genetic Algorithms, and the sum of ratio which the real force of five propellers occupy each maximum force at a given wind velocity is considered as the fitness function, and roulette wheel selection is chosen as the selection methods to ensure the capability calculation Genetic Algorithms has convergence. The results of calculation show that this method owns the same accuracy as the normal capability calculation, and less time is used in the calculation process.

The advanced integrated control and display system of the manned submarine

The manipulations of the manned submarine influence the submarines performance directly. This paper introduces a kind of integrated control and display system for a deep-diving submarine. This system realizes the submarines motion controls of keeping given heading, depth and speed. The information of submarines condition is displayed on CRT synthetically and dynamically. The system has a good man-machine interface, which is very convenient for operating. The fine test result of the system had been obtained. The advanced integrated control and display system has been delivered to the user.