Research On Measurement And Control Of Rolling Angle Of Large Inertial Test Platform

When a ship is sailing at sea,it is affected by external factors such as sea breeze,waves,ocean currents,etc.,which will cause six degrees of freedom motions of rolling,pitching,swaying,swaying,and swaying.The most harmful one is rolling,which seriously affects the ship’s structural strength,stability,ship equipment,and even endanger the safety of the whole ship.Therefore,it is particularly important to study the state of the ship’s substantial roll motion under high risk sea conditions.The ship roll test is mostly performed at sea.Due to weather and other factors,the roll angle is uncontrollable,and the cost and risk of sea experiment is high.Therefore,combined with key construction projects,it is planned to set up a rolling simulation test platform in a laboratory environment.The platform simulates the long-cycle roll motion of the ship at certain frequencies and amplitudes.Under the laboratory conditions,the driving section is used to drive the compartment to roll for a long time according to the set swing angle and period,and the actual roll motion of the compartment at sea is simulated with the purpose of testing the equipment in the cabin.In this way,it brings the advantages of effectively shortening the test cycle,saving costs,and increasing the security and controllability of the test.This paper introduces the main components of the rolling simulation test platform,analyzes the characteristics of the hydraulic drive system and the rolling compartment,establishes their respective mathematical models,and builds a whole system simulation model based on the AMESim simulation software according to the actual system parameters in order to laid the foundation for the research of control algorithm.The effective measurement of rolling angle and angular velocity for a long time is the basis of the control system.Due to the long period of the experiment and high measurement accuracy requirements,general inertial angle measurement sensors are easy to produce large drifts.Therefore,a dynamic measurement device for the rolling angle based on a MEMS compass sensor is developed in this paper.Through comparison and selection,a sensor module with appropriate performance is selected for integration and packaging.In order to reduce the influence of the electromagnetic interference in the compartment,a data processing algorithm including data filtering and fusion for measurement is proposed in this paper to improve the measurement accuracy.A large number of static tests and dedicated test benches have verified the performance of the measurement device.The device provides measurement information for the control system.The mass of the rolling simulation test platform is large and so is the inertia.The hydraulic drive system is an underpowered system.It cannot directly drive the compartment to the set angle of 45 °.Therefore,the combined torque of traction and inertia is used.The compartment gradually rolls to 45 °.Different control strategies were adopted in the rolling start-up phase and the stabilization phase.The control algorithm of double closed-loop control is proposed.The outer loop is the swing angle step plan.The swing process is divided into 5 stages through the analysis of the motor output torque and the feedback of rolling angle;the inner loop is the rolling angle following control which is realized by the fuzzy self-tuning PI controller,and the bottom layer is winch closed-loop control.The controlled objects of the rolling simulation test platform are scattered.In this paper,the control system architecture is designed in the form of upper and lower computers.The software and hardware of the control system are introduced in detail.As the actual rolling simulation test platform has not yet been completed,this paper introduces a semi-physical simulation joint system based on the semi-physical simulation system and the actual control system.Tests are designed.The control system interface,communication protocol,control strategy and algorithm,function of the system are verified.The control system and control algorithm are proved to be effective.