| Ultrasonic motor is a new type of micro-special drive device.It has the advantages of start-stop sensitivity,power-off self-locking,low noise,simple structure,no electromagnetic interference,etc.Compared with traditional motors,it is more suitable for aerospace,precision control and other fields..Ultrasonic motor technology involves a new field of multidisciplinary intersections such as material mechanics,piezoelectric materials science,nonlinear friction theory,and mechanical vibration theory.The theoretical system is complex,and there is still no perfect theoretical basis,especially in the optimization design of motor structure.The stator structure of an ultrasonic motor is one of the key factors affecting the performance of the motor.Based on ANSYS software,this paper makes a detailed simulation study on the stator structure optimization of a linear in-plane bending mode and longitudinal mode modal composite ultrasonic motor.The main work of the thesis is as follows:(1)The feasibility of ultrasonic motor structure design was studied through simulation analysis.Firstly,the simulation convergence test is carried out through modal analysis,and by comparing the reliable data,it is verified that the finite element model of the simulation construction and the boundary conditions are in line with the actual situation.After that,the whole simulation analysis of the ultrasonic motor structure is carried out,and three observation points are selected on the stator to obtain the center of the left and right ends of the stator,or the midpoint of the ridge of the stator is suitable as the driving foot.The results show that the ultrasonic motor can drive the linear motion of the mover and verify the feasibility of the structural design of the ultrasonic motor.(2)The influence of the main structural size parameters of the stator of the ultrasonic motor on the modal coupling is studied Based on the orthogonal test method,the natural frequency difference between the bending mode and the longitudinal mode and the value of the constructing function P away from the interference mode are used to optimize the structural size of the response index.Through the orthogonal test method and the step-by-step design experiment,the structure size of the piezoelectric vibrator is optimized,and the optimal piezoelectric vibrator structure size(length: 32 mm,aspect ratio: 3.8,thickness 1.2mm)is obtained.The optimized natural frequency difference between the bending mode and the longitudinal mode of the piezoelectric vibrator is only 44 Hz.The other interfering modes are not mixed in and the frequency is far from the natural frequencies of the bending mode and the longitudinal mode,which satisfies the requirements of mode degeneracy.(3)Study the influence of different common piezoelectric ceramic materials on the output performance of ultrasonic motor.Based on the optimal structure size of the stator,through the comprehensive simulation analysis of the stator of the ultrasonic motor,the ultrasonic motor structure of different piezoelectric ceramic materials is compared and the piezoelectric ceramic material of the most suitable ultrasonic motor is found as PZT5 H,and the stator structure of the ultrasonic motor is again optimization.(4)Based on the optimization of the above stator structure,the bonding method of the piezoelectric ceramic piece of the ultrasonic motor stator is improved.The original patch-type paste is changed into a piezoelectric ceramic in-line paste,which increases the contact and paste area of the piezoelectric ceramic sheet and the elastic substrate,and improves the energy conversion efficiency between the piezoelectric ceramic sheet and the elastic substrate,thereby improving output performance of the ultrasonic motor.The experimental results show that the output performance of the improved ultrasonic motor is significantly improved.The step size of the embedded ultrasonic motor is about 1.2μm and the no-load speed is 60mm/s.The stator structure of the ultrasonic motor is further optimized. |
PDF Full Text Request