The Research On The Technology About Full Suspension Pneumatic Lifting System Based On Fuzzy-PID Control

Suspended pneumatic lifting system allows the operator to easily complete various tasks on handling,assembling and special workpiece positioning,that it is not only widely used in home appliance manufacturing,automotive assembly,weapons production and other industrial fields,but also improves production efficiency and working conditions as of such great significance.At present,the weakness of the domestic suspended pneumatic lifting system is all its shortcomings,which include low locate precision;poor operational stability,exceedingly small suspension stroke,etc.In terms of manufactures,the possibility of key technology import from abroad is still low,simply copying the structures is the only breakthrough for now.Therefore,a necessary development on a kind of pneumatic lifting system widely used in heavy lifting,material handling and full-duty suspension is vital.At the beginning of this paper,the principle of load suspension in pneumatic lifting system,and function are used to design the whole scheme of pneumatic lifting system that controlled by electrical components and driven air.The detailed analysis and calculation are used for the main part of the system.The overall control scheme of the system is designed to provide the fundamental basis of the further studies for later use.Based on the analysis using the existing friction theory,a test platform analyzing the characteristics of friction is built for a cylinder of pneumatic lifting system running at low speed,while the Stribeck friction formula is used to fit the experimental data.The results show that the Stribeck fitting curve and the experimental curve has a good degree of coincidence,so the Stribeck fitting formula can be used to characterize the actual friction force in the pneumatic lifting system.The dynamic mathematical model of pneumatic lifting system was built on matlab/simulink software.Aiming at the mathematical modeling approach,the PID controller was designed,which the simulation results showed-the response performance of the system was observably improved when kp was 1.43,ki was 0.06,and kd was 0.04.In terms of Fuzzy-PID controller designs for the system,parameters PID controls are set with the default value of Fuzzy-PID controller,and the simulation results show that: the system settling time is in the range of 0.5~0.8s,steady-state error is in the range of 0~3%.The performance test bench for the full suspension pneumatic lifting system is built with kingview configuration software in which the performance and response characteristics of the suspension system are tested.The results show that the translational motion for the load is eastablished in the vertical distance of the lifting system by sustaining the real-time gravity compensation under different operating forces,thus that the hanging load can be fully suspended during the whole course.The dynamic response performance and steady-state error of the system are close to the simulation results.The effective lifting stroke of the pneumatic lifting system is approximately 2007 mm,which meets the design requirements.