Trum Dynamic Modeling And The Optimal Control Of Vibration Mode Vector

Travelling-wave rotary ultrasonic motor(written briefly TRUM)is a typical kind of ultrasonic motor,which is wildly used in some high-grade,precision and advanced applications based on the advantages such as no electromagnetic interference,high torque density and direct-drive in low speed.However,ultrasonic motor is a fruit of multi-theories development,which integrates the materials,mechanical,electrical control and the other subjects,and many key technologies need further research.Here,some necessary problems of modeling,dynamic response and control will be studied deeply.1.A mixed modeling method of TRUM is proposed focusing on the two energy transmitting process and the Electric,Viberation and Force principle in them.Two sub-models,one is the “E-V” equivalent circuit model with the electric input port for the stator,the other is the “V-F” discrete contact model for the interface between the stator and the rotor which can simplify the nonlinear calculation,are combined with some interface parameters to compose the mixed model.The electric characteristics,the contact characteristics and the mechanism characteristics of the TRUM are analized with the mixed model and the accuracy of the model is verified by some experiments.2.According to the theories of space vector of electromagnetic motors,the same methods of space vector are put forward for TRUMs.The voltage resposes of vibration mode vector are analyzed from both theoretical deductions and simulations.The zero input response and the zero state response of step voltage and sinusoidal voltage are deduced by the linearized mode equation,at the same time,the simulation results are compared with the deduction,by which the relationships among the voltage,vibration mode and the torque are acquired to lay the foundation for the study of control.3.The traditional control of the voltage amplitude,frequency and phase for TRUM are researched by space vector.The motor control and the servo control methods for the TRUM are proposed in different ways.Firstly,the energy utilization ratio and voltage balance of the two phases are considered in the motor control,and the coordination control of the two-phase vibration modes is achieved by mode observer.Secondly,for the servo control of the TRUM,a novel method that named discrete dynamic predictive control of vibration mode vector is put forward to directly control the viberation mode of the motor,which is also used in the micro step control in the following part.At last,a traditional micro step control is analyzed for the comparison of the new strategy.In the new one,the two-phase vibration modes are planned by a ridge-shaped function and controlled by the predictive method mentioned abve,which are better than the existing method.4.A full bridge controller is designed in the last part,which combine a DSP and a CPLD as the core to achieve a phase-shifting PWM control logic to control the voltage amplitude,frequency and phase easily.For the power circuit,the drive structure of the H-bridge and the parameters of the high frequency power pulse transformer and the matching inductance are presented.The controller and partitial control methods are verified by experiments.