Research On Anti-high Impact Overload Ultrasonic Motor Used In Missile-borne Servo

A novel supersonic motor with high overload resistance and being integrated with the cannonball,is designed for the purpose of accurate strike.Its behaviors under the high impact loadings same as those in the cannon barrel during firing process are experimentally studied using the porotype of the designed motor.The major loadings(forces)during firing is determined to be the axial inertial forces from the mechanical analysis.And the mechanical loadings are obtained through simulations for the acceleration curve during the process,which is further used to obtain the mechanical loadings.The comparisons are made between the “forward” and “backward” installation methods through the investigation of the interactions among the components of the supersonic motor.Transient analyses under previously obtained impact loadings are carried out and the numerical results are used to consider the advantages and disadvantages of both methods,which leads to the selection of “forward” installation method.Based on the previous numerical results,the design of the stator,which is also the weakest component in the motor,is optimized.In order to improve the impact resistance capability for the normal working state,the optimization is made by numerical analyses of the modals,the amplitude and the impact resistance behavior for the cases of various dimension parameters.Since residual stresses have been caused in the stator by the impact,the corresponding modal and harmonic response analyses are also made to study the influence of the residual stresses in the characteristics of the Ultrasonic motor behavior.After the stator design optimization,the dimensions of other components of the Ultrasonic motor like the base and rotating shaft are determined.In this way a novel Ultrasonic motor is designed.The transient analyses for this new motor are made and the results reveal that the impact resistance is significantly improved and no plastic deformation occurs after impact.Based on these works,porotype of new Ultrasonic motor is made.Marshall's drop hammer tests are carried out on the porotype to measure the mechanical behaviors and the impact resistance.The experimental results show that the output performance are stable and good even after the impact loading as high as 900 g is loaded on the motor.The study here has set the basis for the precision control of the guided cannonball and may be meaningful for other related engineering fields.