Design And Research On Self-leveling Lifts Based On 3-RPS Parallel Mechanism

Lift is a widely used aerial work machine,the current development of the lift is mainly for the flat road,in order to solve the problem that folding arm lift cannot work well on the slopes,a design scheme of self-leveling lift based on 3-RPS parallel mechanism with equivalent spherical hinge was proposed by the use of 3-RPS parallel mechanism with leveling characteristics and the requirement of the range of the rotation angle was also taken into consideration.In this paper,the characteristics of the lift mechanism,the overall design scheme,statics,kinematics and virtual simulation were studied.The main research content are as follows:The spatial position of the move platform of 3-RPS parallel mechanism was described by the Euler angle and the rotation matrix of the Z-Y-Z Euler angle was deduced;The anti-solution analysis of the parallel mechanism was completed by using the analytical method;The general form of velocity Jacobian matrix was established and the velocity Jacobian matrix expressed by Z-Y-Z Euler angle was deduced;The static Jacobian matrix of the 3-RPS parallel mechanism with spherical hinge was established and the static Jacobian matrix of the 3-RPS parallel mechanism was further deduced.A design scheme of self-leveling lift based on 3-RPS parallel mechanism with equivalent spherical hinge was proposed by the combination of the parallel mechanism and the series mechanism as well as the requirement of the range of the rotation angle.This design not only makes the lift have the leveling function but also endowed it with the advantages of stable structure and compactness.Based on the requirement of working height and the parameters of the vehicle,the dimensions of the main parts of the lift were obtained.Based on the obtained actual size,the structures of static platform,the move platform,the equivalent spherical hinge and the support leg were designed.The strength of the folding arm was checked.The entity model of the whole machine was established by SolidWorks,the longitudinal stability and lateral stability of the lifts were analyzed theoretically.The statics model of the lift was established and the statics model of the 3-RPS parallel mechanism with the equivalent spherical hinge was further studied.The statics model of the 3-RPS parallel mechanism with equivalent spherical hinge was verified compared with the statics model of the traditional 3-RPS parallel mechanism.The parts of the equivalent spherical hinge were designed in detail and the maximum value of the axial force and radial force of the cylinder were determined,also,the corresponding method of reducing the force was given.Kinematics simulation was carried out by ADAMS,simulation results proved the validity of the theoretical analysis.The function prototype was developed and experiment was carried out.The prototype tests also showed that the proposed method was reasonable and feasible.