Research On Vibration Control Of Fire Ladder Iruck

Nowadays,more and more tall buildings appear in the city,and the ladder truck with capabilities of high-altitude fire fighting and rescue is becoming increasingly important.However,the boom control technology of the ladder truck is not intelligent enough.When the motion control command changes drastically or the system is disturbed by external forces,the boom of the ladder truck will generate large amplitude vibration,which not only affects the work efficiency,but also poses a threat to the safety of personnel.Therefore,it is of great theoretical value and practical significance to study the stability control technology of ladder truck's boom system.The boom system of ladder is a nonlinear and strong coupling dynamic system,which can be divided into three parts:boom mechanism,hydraulic system and control system.In this paper,the boom system of the ladder truck is taken as the research object,and this work carries out study in vibration analysis and modeling of the boom mechanism,analysis and modeling of the hydraulic system and design and functional verification of the control system.The main research contents in this paper are as follows:(1)The modal analysis of the boom mechanism is carried out,and its low-order natural frequencies and corresponding vibration modes are obtained.A rigid-flexible coupling multi-body dynamics model of the boom mechanism is established using Virtual.lab Motion,which becomes the foundation of the vibration control scheme development.(2)The functions and characteristics of the hydraulic system are analyzed,and the hydraulic system model with corresponding functions is built using AMEsim.(3)The vibration mechanism of the boom is analyzed.A control scheme to improve the smoothness of the motion control command is proposed to prevent boom vibration generated by abrupt changes in operation command.The effectiveness of the control scheme is proved under the co-simulation environment by using the model of the arm structure and the hydraulic system built before.(4)Vibration experiments are implemented on a real ladder truck.The oscillating operation signal and the external force disturbance are respectively applied to stimulate the vibration of boom,and the filtered experimental data is processed using the FFT technique to obtain the frequency spectrum diagram of the critical position of the boom system during free vibration,and the vibration parameters of the boom are extracted.The proposed vibration control algorithm is introduced into the control system and the previous experiment is repeated.The two sets of experimental data are compared and analyzed to evaluate the feasibility of the vibration control scheme.(5)An active control strategy based on commandless input shaping technique is proposed for boom vibration generated by external force.In addition,a position compensator is introduced to maintain the same position of the boom.In order to verify the performance of the control strategy,a co-simulation environment of boom system based on Motion,AMESim and Simulink is established,and the external force disturbance response of the boom system is analyzed through the co-simulation.This paper provides an effective solution for the stability control of the boom system of ladder truck,and also provides a new idea for the stability control of the large boom system.