Experimental Researches And Performance Analysis Of Ultrasonic Motor Under High Speed Rotating Conditions

Guided weapons play an increasingly important role in modern warfare.Grenades,as the backbone of the national army’s weapons,are the focus of the research on the field of guided projectile.In this paper,according to the operating characteristics of high-rotation grenades,with the advantages of light and simple structure,fast response,high resolution,self-locking,direct drive,etc.,ultrasonic motor can be used as the executive mechanism of precision guided kit.However,the environment during launching and flight is very harsh.Due to the specific structure of the stator,the strong centrifugal field has a strong influence on the actuator,especially the stator,of the guidance assembly.In this research background,the dynamic model of the stator under the action of centrifugal field is established,and the warping deformation of the stator in the centrifugal field and the change of the contact force between the stator and the rotor are calculated.Finally,the rotational speed and torque of the ultrasonic motor in high revolution speed are measured in the experiment.The main contents of this paper are as follows:1.Finite element theory,semi-analytical ring element and plate shell theory were comprehensively used to derive the semi-analytical dynamic model of the stator under the centrifugal field,according to the model,the dynamic characteristics of the different material stator under the centrifugal field changes are calculated;the modal state of the stator loaded with the speed load is calculated by using finite element analysis software.The results show that the operating frequencies of phosphor bronze,65 Mn and aluminum stator are affected by the centrifugal field and the frequency increases with the increase of speed load.The simulation results of the model are consistent with the trend of ANSYS simulation results,but the results of model simulation are larger.2.The plate-shell theory was used to derive the centrifugal deflection of the stator due to the action of the centrifugal field.Through the calculation of the model,it was found that the centrifugal deflection of the stator increased with the increase of the rotational speed load;The change of contact interface force between stator and rotor caused by stator warping under centrifugal field was deduced.The change of the contact interface force between the rotors resulted in the relationship between the output torque and the centrifugal deflection.It was found that the locked-rotor torque of the motor decreases with the increase of the centrifugal deflection.And when the speed exceeds 13000r/min,the stall torque of the ultrasonic motor equipped with the 40 mm phosphor bronze stator rotates is reduced to 0N.m.3.A new type of rotation speed and torque measuring device with simple structure and high precision is designed.The speed and torque output characteristics of the ultrasonic motor under different rotating speeds are obtained.The stator parameters are analyzed using the finite element analysis software to analyze the variable parameters of the stator.Reducing its sensitivity to high rotating speed environment is instructive to the analysis of high-spinning stator and motor reliability.