Quasi-zero Stiffness Dynamics Analysis And Design Of Rotating Traveling Wave Ultrasonic Motor Rotor

The disc-type rotating traveling wave ultrasonic motor has the advantages of compact structure,fast response,low speed and high torque,and has a good application prospect in the use of the ultrasonic motor in the missile driving system.The guided projectile will generate a huge high-impact overload during the internal ballistic phase of the launch,and the carrying capacity of the actuator will determine whether the guidance system is operating normally.In this paper,aiming at the working environment such as high overload and long-term storage requirements of internal ballistics during projectile launch,a quasi-zero-rigidity disc spring rotor of ultrasonic motor with constant external pre-pressure is proposed.The paper is based on the force transfer model and vulnerable component analysis of ultrasonic motor under high impact,the ultrasonic motor dynamics model considering the stiffness of the pre-stress system,the parameter optimization design of the disc spring rotor with quasi-zero stiffness,the prototype test and the system experiment.Research.The specific research contents are summarized as follows:1.This paper introduces the working principle and use environment of artillery-launched missiles,the research status at home and abroad,explains the control methods currently adopted by the steering gear,proposes the control methods and advantages of the piezoelectric steering gear,and introduces the working principle,advantages and existing difficulties of the ultrasonic motor.Finally,the research objectives and main contents of this paper are pointed out.2.According to the application background of the high impact environment of the guided projectile,combined with the structural mechanism of the disc ultrasonic motor,the force transmission characteristics of each part of the ultrasonic motor under the impact environment are analyzed,and the finite element analysis and the Marshall hammer test are carried out on the vulnerable parts after the impact.analysis.3.The rotor model of the ultrasonic motor considering the structural stiffness of the pre-stress system is established to explain the driving mechanism of the ultrasonic motor under the action of nonconstant pre-pressure.It is pointed out that the vibration of the rotor along the axial direction will affect the output performance of the motor.It is theoretically verified that there is a quasi-zero stiffness prepreparation.The pressure applying mechanism will effectively improve the speed characteristics.4.A quasi-zero-stiffness disc spring rotor configuration with constant pre-pressure is proposed.The ideal pre-stress system stiffness is obtained by using the slotted topology.The parametric finite element model of the selected configuration is established,and the main design variables are selected by sensitivity analysis.An optimization function is established to optimize the parameters of the disc spring rotor.The optimization results ensure that the disc spring rotor has good stiffness characteristics and strength.5.According to the optimization results,the prototype was tested,the quality comparison analysis and stiffness test were carried out on the processed disc spring rotor,and the experimental platform was built to analyze the output characteristics of the ultrasonic motor equipped with the disc spring rotor.The optimized rotor has a 11% lower quality than the flexible rotor(favorable for overload resistance)and a quasi-zero stiffness region length of 0.6 mm.The material strength requirement is met in the impact environment.The performance of the disc spring rotor ultrasonic motor is verified by experiments.