Study On Vibration Suppression For Luffing System Of Knuckle Boom Aerial Platforms

In high-altitude operations such as high-altitude construction,maintenance and rescue,the aerial platform is playing a vital role.And as the increasing requirements for aerial work and the complexity of the working environment,the aerial platform is developing in a higher,faster and lighter direction.Higher requirements for the safety,stability and intelligence are put.Therefore,in order to improve work efficiency and ensure the safety of the staff,it is of great practical engineering significance to study the vibration suppression of the boom system of the aerial platform.In this paper,a knuckle boom aerial platform,which is easy-to-move and compact,is taken as the research object.The vibration of the boom system during the luffing process are aimed.The luffing hydraulic and boom system are modelled and analyzed respectively.And using the singular perturbation theory,the vibration control analysis is carried out from the two angles of the vibration of the changing angle and elastic vibration of the flexible boom.A hybrid control method is proposed to suppress the vibration of the boom system.The main research contents of this paper are as follows:(1)The luffing hydraulic system of the aerial platform is introduced and analyzed.The mathematical models of the hydraulic system is built and the corresponding transfer functions are obtained.The overall function of the electro-hydraulic proportional control system is constructed to get the stability of the hydraulic system.Through the response and correction analysis,the demand for response in time from electrical signals to mechanical signals is realized.(2)The boom system of the aerial platform is introduced.Based on the Lagrange equation,the multi-rigid body dynamic model and the flexible multi-body dynamic model of the boom system are established.Considering the characteristics of equal-section flexible boom and variable-section flexible boom,the modeling and simulation are carried out.Through simulation comparison,the main causes of vibration of the boom system are analyzed.(3)Based on the singular perturbation theory,the flexible multi-body system of the boom system is decomposed into a large-scale luffing slow-variable subsystem and a flexible boom end vibration fast-variable subsystem.Through the analysis of the two systems,PID control and linear quadratic optimal control are used for hybrid control.(4)The simulation model with the expected angle electrical signal as input is established.And the boom vibration control system is modeled and simulated.The effectiveness of the hybrid control for boom vibration suppression is analyzed.