Ship Parameter Identification Method Based on Improved Maximum Likelihood Method and Confidence Compression Filter
A technology of maximum likelihood and confidence compression, applied in complex mathematical operations and other directions, it can solve problems such as slow convergence speed, and achieve the effects of simple calculation, avoiding particle degradation, and high filtering accuracy.
Active Publication Date: 2019-01-11
HARBIN ENG UNIV
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However, the maximum likelihood method needs a considerable number of iterations to converge to the correct result, and the convergence speed is slow.
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[0043] The present invention will be further described in detail below in conjunction with the accompanying drawings.
[0044] The present invention describes a new method for identifying ship parameters, which uses an improved maximum likelihood method and a confidence compression filtering method. figure 1 Shown. Specific steps are as follows:
[0045] (1) Use the ship's own propeller, rudder and other actuators to apply force and moment to the ship to make the ship perform a specific movement, specifically:
[0046] Control the ship’s propeller, rudder and other actuators through the controller, and record the propulsion and torque at each sampling moment; the overall motion of the ship should be determined strictly in accordance with the ship model; in order to make the ship complete a specific motion, use The additional mechanical structure imposes external forces and moments on the ship, and the applied external forces and moments must be measurable and recorded.
[0047] (2) ...
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The invention discloses a ship parameter identification method based on an improved maximum likelihood method and confidence compressed filter. The method comprises a first step of measuring the force and moment applied on a ship by an actuator, taking the force and moment as control input, collecting information of displacement and an attitude angle, taking the information as output observed quantity, setting an original state estimated value, establishing a ship model according to the control input and the output observed quantity, and obtaining parameters of the ship model to be identified; a second step of according to current sate estimated value of the ship and output observed quantity Eta, identifying the parameter estimated value of the ship model by the improved maximum likelihood method; and a third step of according to the identified parameter estimated value of the ship model, upgrading the current state estimated value by the confidence compressed filter, repeating the second step and third step till stopping outputting the output observed quantity of the ship, and acquiring the parameter estimated value of each sampling time. The method is simple in computing, has high execution efficiency and accurate identification result, and can operate online.
Description
Technical field [0001] The invention belongs to a method for identifying ship parameters, in particular to a method for identifying unknown parameters in a ship time domain state space model based on an improved maximum likelihood method and confidence compression filtering. Background technique [0002] The attitude control of a ship during sailing is a complicated problem. The ship has 6 degrees of freedom, the motion equation of the ship is highly nonlinear, and the hydrodynamic coefficients are coupled with each other; at the same time, the ship is disturbed by uncertain ocean currents, waves, wind, etc. during navigation, and the actuator has hysteresis , This has caused great difficulties in the control of ships. In order to accurately control the ship, it is generally necessary to establish an accurate ship model, and further need to identify the ship parameters including hydrodynamic coefficients to reduce the uncertainty of control. Ship parameters can be obtained thro...
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IPC IPC(8): G06F17/17
Inventor 陈虹丽王子元沈丹宋东辉宋景慧龚洛
Owner HARBIN ENG UNIV