Analysis And Design On Hydraulic Control System Of Lifting Booms Of Aerial Work Platform

Aerial Work Platform in aerial machinery fields will bring about a bright future inChina with the rapid demands of aerial constructions. The function of Aerial WorkPlatform is to carry operator and maintaining tools getting to the position of workingplace steadily and safely, the subject of this paper comes from the technical project ofkey technique and application of Aerial Work Platform operating system inChongqing.The course of lifting is simulated through the method of computersimulation; paremters of lifting cylinders are caculated and stability of cylinders arechecked. Circults of hydraulic of lifting booms have been designed according tocharacteristics of Aerial Work Platform, simulations is done by AMESim. In order toobtain step response of leveling system, elec-hydraulic model of it is established.Finally, a distributed control scheme is given in upper and down vehicle according tocharacteristics of operationThe mainly contents of this paper are shown below:(1) The3-D model of lifting booms of folded booms of Aerial Work Platform isbuilt. The simulation of lifting booms is achieved by using multi-body dynamicssoftware MSC.ADAMS. In the paper, liftting course is simulated by pieced drivingfunction, and getting the actuator applied force, finally, parameters of cylinders arecaculated through simulation outcomes and stability of cylinders is proved.(2) Leveling of working platform, as a crtical technique, which reliability andstability will affect operator safty and riding comfort in lifting course. To ensurereliable leveling, an adavanced leveling techenique is applied in the aerial workingplatform, that is so called elec-hydraulic automatic leveling, modeling ofelec-hydraulic leveling is established, using Matlab to analyse stability of levelingthrough the frequency response method in classical control theory, at last, to obtain thebest opened-cricult amplification factor to assure system stability.(3) In order to assure the stability of speed of lifting cylinder,a kind circultowning load sensing and pressure compensator has been designed The simulation ofhydraulic system of lifting has been achieved by using AMESim, simulation resultsshow that speed of lifting cylinder will be keeped steadily, when directional valveequipped with pressure compensator is used. It will be of great significance to improvesafty and ride comfort for operator. (4) In order to realize the function of upper and down platform control, adistributed controller is designed with separated mini-controllers in operator platformand rotating platforms. Such design can make a high production efficiency and safty inwork operating.