Research On Stability Of Stereoscopic Warehouse Stacker Crane

With the progress of science and technology, research on stability of stereoscopicwarehouse stacker crane becomes to be concerned by more and more people. The vibrationof stereoscopic warehouse stacker crane in operation can cause positioning inaccuracy,running unsteadiness and the cargo insecurity of stacker crane. Seriously, stereoscopicwarehouse stacker crane and its components may be damaged by the vibration. Therefore,this paper mainly focuses on research on the stability of stereoscopic warehouse stackercrane.Static structural deformation on portal frame and axle in running mechanism ofstereoscopic warehouse stacker crane is analyzed by finite element commercial software.The deformation in X, Y, Z direction is observed for insuring positioning accuracy,running steadiness of the crane on load. The modal analysis on the running mechanism iscompleted. The natural frequencies and the vibration modes of the portal frame and axleare obtained, which provides design foundation for avoiding resonance resulting fromnature frequencies coinciding with running frequencies. Furthermore, the vibrationmagnitude of stereoscopic warehouse stacker crane is effectively suppressed.The stability problem of permanent magnet synchronous motor which is the driverunit of stereoscopic warehouse stacker crane is deeply researched. The variation of themagnetic field between no load and on load is analyzed by using ANSYS finite elementsoftware. The waveforms of radial magnetic flux density, tangential magnetic flux density,radial force density and tangential force density varying with position in air gap in thetwo situations are gained. Based on above results, the variation of the magnetic field in airgap while the rotor rotates is calculated. The waveforms of radial magnetic flux density,tangential magnetic flux density, radial force density and tangential force density changedwith time are gained. The variation of the tangential force magnitude with time iscalculated by numerical integration. The variation regulation of cogging torque ofpermanent magnet synchronous motor is ultimately obtained. One of influence factors on the stability of stereoscopic warehouse stacker crane iscogging torque of the motor. The method of reducing cogging torque by improving designparameter of the motor is presented. The cogging torque of4pole,48slot motor and6pole,54slot motor are calculated based on Finite Element Method. The conclusion is thatcogging torque of the motor can be reduced by selecting pole and slot number combinationand ratio of the pole arc to pole pitch. The influence of different length of air gap oncogging torque is also researched based on6pole,54slot motor in this paper. The coggingtorque is sharply reduced at initialization, then reduced slowly with increasing of air gap.The “inflexion point” is the optimal length of air gap. Cogging torque of the motor can beweaken effectively by taking above measures. The stability of stereoscopic warehousestacker crane can be improved.