Dynamic Analysis Of Crane Working Mechanism Based On Permanent Magnet Speed Regulation Technology

With the progress of science and technology,the concept of energy saving and green manufacturing has been put forward,the industrial heavy lifting equipment proposed a higher design requirements,low speed and high torque direct drive technology gradually applied to the working mechanism of crane.Compared with classical three-phase asynchronous motor reducer drive device structure,the variable speed permanent magnet synchronous motor drive system is simple in structure,which doesn’t need complicated deceleration transmission system,and the torque is constant,the output torque is big,it accords with the special requirements of heavy machinery applications.In this paper,the dynamic characteristics of the crane working mechanism are analyzed based on the permanent magnet direct drive technology,which provides the theoretical basis for the determination of the dynamic load coefficient of the direct drive crane.The subject has certain engineering significance.In this paper,the generalized bridge crane is used as the research object,and its driving system is changed to the new low-speed and high-speed constant-speed synchronous motor.Combined with the actual use of crane conditions,the multi-degree-of-freedom mechanical model of the crane working mechanism is established.According to the various working conditions of the crane,the initial conditions of the lifting mechanism under different working conditions are analyzed.The parameters of the hoisting mechanism are obtained by referring to the literature and using the modern mathematical calculation method to derive the quality,stiffness and damping in the model.The output torque of the permanent magnet motor is obtained by using MATLAB software to simulate the variable speed permanent magnet motor.Finally,the simulation model of hoisting mechanism is established by Simulink software in MATLAB.The dynamic load characteristics of different working conditions are simulated and the computer aided software "crane dynamic load factor analysis system" is written with VC ++ 6.0.The simulation results show that the influence of the stiffness level of the main girder on the lifting coefficient of the direct drive crane is limited,which is mainly affected by the lifting speed and the pulley group magnification.When the lifting speed is reached 20m/ min,the relationship is close to (?)2=1+v;The pulley group magnification increases by a factor of about 10%;Sudden mechanical hard braking will produce more than other conditions of the dynamic load,so the actual production to avoid this sudden situation,the combination of electric brake and mechanical brake should be taken to achieve soft braking effect.