| Micro-wave ultrasonic motor is a new type of motor manufactured by MEMS(Micro-Electro-Mechanical Systems)technology.It has the advantages of simple and compact structure,fast response,large torque,low noise,and strong self-locking ability.It has wide applications in aerospace,medical equipment,precision instruments,and other fields.The application of micro ultrasonic motor is usually used to achieve precise positioning or stepping drive.The starting characteristics of the microscopic motor directly determine the precision positioning and the advantages and disadvantages of stepping drive.Therefore,an in-depth study of the starting characteristics of the ultrasonic motor for the micro-ultrasonic motor The improvement of positioning accuracy plays an important role.In this paper,the micro-wave ultrasonic motor is used to investigate the variation of the speed of the micro-wave ultrasonic motor during the acceleration process,and the correctness of the theory is verified by experiments.The research content of this paper mainly has the following parts:1.Study on the formation mechanism of traveling waves.Through the piezoelectric equation,the deformation of the piezoelectric ceramic on the stator of the traveling wave ultrasonic motor under voltage excitation is analyzed.Under the action of multiple piezoelectric ceramic coverage regions,the stator will vibrate and stimulate the corresponding mode to form a standing wave.Subsequently,the two columns of standing waves are superimposed into a row of traveling waves,which realizes the traveling wave excitation of the stator of the motor.2.Drive contact characteristics and startup characteristics studies.The motion law of the surface wave point of the stator traveling wave is analyzed by Kirchhoff's thin plate law.The variation of the traveling wave waveform in the radial direction is analyzed according to the COMSOL simulation software.The contact model under the cylindrical coordinate system is established as a reference.The model is based on the analysis.The variation of the normal pressure distribution in the contact area between the traveling wave and the friction layer.Combined with the motion law of the mass point on the traveling wave,the distribution of the tangential force of the contact area is analyzed,and the change of the rotational speed of the rotor during the starting process is derived.3.Micro motor structure design.A new motor stator with a support beam at the toroidal pitch is designed to achieve a reduction in anchor loss.The annular stator model is established by using COMSOL finite element software.The stator performance is analyzed by vibration mode analysis and transient response of the motor stator,and the stator is optimized according to the analysis result.Then the pre-tightening structure between stator and rotor is designed by ANSYS finite element software to complete the structural design of the whole motor.4.Experimental verification.The stator of the micro traveling wave ultrasonic motor was fabricated by using the micro-machining technology.The experimental platform was built by laser Doppler vibrometer to test the driving frequency and traveling wave excitation of the stator.The high-speed camera is used to complete the no-load rotation experiment of the motor sample,which verifies the correctness and effectiveness of the starting theory.In this paper,a new type of stator and rotor contact model is established considering the change of the traveling wave waveform of the micro traveling wave ultrasonic motor in the radial direction,and the change of the rotational speed of the ultrasonic motor during the starting process is analyzed based on the model.It is of great significance for this type of ultrasonic motor application. |
PDF Full Text Request