Research On Information Measurement Technology Of Ship Pitch Roll And Heave Based On IMU

In recent years,in the development of marine resources,marine scientific research and other activities,various marine engineering vessels have been widely used in offshore engineering operations in related fields.These ships are affected by environmental factors such as sea waves,sea breezes,and ocean currents when they are sailing and operating at sea,and will produce a variety of swaying movements.Among them,the ship's pitching,rolling and heave movements are the most harmful.Practical applications and research have shown that the accurate measurement of ship's pitch,roll and heave motion is of great significance,and it can lay a good foundation for the design of ship control and efficient wave compensation system.According to the above situation,this article has carried out the research on the measurement technology of the ship's pitch,roll and heave motion,mainly including the following aspects of research.(1)On the basis of fully understanding the basic principles of strapdown inertial navigation system and the navigation solution process,the ship's pitch,roll and heave motion measurement principles are given.According to the error equation of the strapdown inertial navigation system,the key factors influencing the ship's pitch and roll measurement are analyzed,and the key factors influencing the ship's heave measurement are analyzed according to the characteristics of Schuler oscillation and altitude channel resolution.Build an experimental environment for ship's roll and heave measurement,and provide data support and verification methods for the roll and heave measurement algorithms designed in this paper.(2)For the ship's roll measurement problem,the overall plan for roll measurement is designed.In order to obtain accurate sensor output data,an inertial device output model is established,and the inertial device is calibrated and compensated by designing a turntable experiment.Based on the quaternion extended Kalman filter algorithm,the output information of the gyroscope and accelerometer is fused to realize the vertical and horizontal measurement of the carrier,and the designed algorithm is verified through the vertical and horizontal measurement experiment.(3)Based on digital high-pass filtering,ship heave information measurement and experimental verification of the research method.The realization principle and design method of IIR digital high-pass filter are given.The influence of filter order and filter cut-off frequency on the filter performance in IIR digital high-pass filter technical index is analyzed,and then the optimal technical index of filter is designed and designed.The best IIR digital high-pass filter for ship heave measurement.The phase advance problem exists around the digital high-pass filter.The phase error problem is solved by first designing an IIR digital low-pass filter that meets the technical specifications,and then converting to a digital high-pass filter based on the complementary idea.Experiments verify the designed algorithm.feasibility.(4)In order to avoid the problem of phase advance in the measurement of ship heave information using digital high-pass filtering,this paper proposes a method for measuring ship heave information based on unscented Kalman filtering.According to the ship heave motion model,the relationship model of the ship heave motion position,speed,acceleration and frequency is established.For the frequency information that the model depends on,the fast Fourier transform and peak detection algorithm are introduced to analyze the frequency spectrum of the ship's heave acceleration signal,and then the required heave motion frequency information is obtained.The state space model of the ship heave measurement is derived,and then the state equation and measurement equation of the ship heave measurement system are established according to this model,and finally the solution is based on the unscented Kalman filter.Simulation and platform experiments prove that this method has no phase problem and can obtain accurate heave information.