Dynamic response for electromechanical integrated toroidal drive to electric excitation

Xu, Lizhong,Hao, Xiuhong Techno-Press 2007 Structural Engineering and Mechanics, An Int'l Jou Vol.26 No.6

In this paper, the equivalent exciting force caused by electric excitation is derived. By dividing load and displacement vectors into mean values and time-varying ones, the dynamic equations of the system are transformed into linear ones for time-varying portion of the displacements. The analytical equations of the forced time responses of the drive system to electric excitations are obtained. Using the Laplace transformation, the transfer function of the drive system is obtained. These equations are used to analyze the time and frequency responses of the drive system to the electric excitation. It is known that electric excitation can cause forced responses of the drive system, the total dynamic responses are decided by three phase exciting voltages, exciting frequency and natural frequencies of the drive system, and the drive parameters have obvious influence on the time and frequency responses.

Forced response of the inertial piezoelectric rotary motor to electric excitation

Lizhong Xu,Jichun Xing 대한기계학회 2015 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.29 No.11

For a novel inertial piezoelectric rotary motor, the equation of the voltage response on the piezo-ceramic bimorph under the excitationsignals is deduced and the dynamic equation of the motor rotor is given. Using the equations, the voltage responses on the piezo-ceramicbimorph and the responses of the displacement, velocity and acceleration on the rotor to the sawtooth voltage excitation are investigated. The results show that when the frequency of the excitation signal is quite low, the waveform of the displacement response of the rotor isidentical to one of the excitation signal; the outer diameter of the rotor, its length and thickness, etc., have obvious effects on the inertialmoment applied to the rotor. The results are useful for design and control of the operating performance of the motor.

Effects of eccentricity on dynamic behavior of electromechanical integrated electrostatic harmonic actuator

Lizhong Xu,Xu Shi 대한기계학회 2013 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.27 No.9

The authors earlier invented an electromechanical integrated electrostatic harmonic actuator consisting of a flexible ring and segmented stator. As the dimension of the actuator decreases, the effect of ring eccentricity on the dynamic behavior of the actuator becomes significant. In this paper, the equations for the displacements of the flexible ring and the electromechanical coupled dynamic equations under eccentricity are deduced. Using these equations, changes of the natural frequencies and vibrating modes as a function of the eccentric center distance are analyzed. For different eccentric center distances, changes of the forced response along with the system parameters are given. Results show that the ring eccentricity causes significant changes of the natural frequencies and vibrating amplitudes of the flexible ring, which could cause loss of the load-carrying ability for the actuator. The flexible ring radius, thickness, and clearance and voltage between the flexible ring and stator influence the relationship between the eccentricity and the dynamic behavior of the actuator.

Displacements of the helical stator tooth for an electromechanical integrated toroidal drive

Xu, Lizhong,Zheng, Dazhou Techno-Press 2009 Interaction and multiscale mechanics Vol.2 No.4

The stator tooth is a key component of the electromechanical integrated toroidal drive system. The stator tooth is spiral in shape and the calculation of its displacements is difficult. In this paper, using the coordinate transformation method, the displacements of the stator tooth in the local coordinate system are expressed as the function of the variable in the drive coordinate system. Using the minimum potential energy principle, the equations of the displacements of the stator tooth under the loads are deduced. The displacement distributions within the stator tooth are investigated and the changes of the displacement distributions along with the main parameters are analyzed. This research can offer the basis for the strength and stiffness design of the drive system.

Force and stress for electromechanical integrated toroidal drive

Lizhong Xu,Jin Huang 국제구조공학회 2010 Structural Engineering and Mechanics, An Int'l Jou Vol.35 No.3

Double displacement coupled forced response for electromechanical integrated electrostatic harmonic drive

Lizhong Xu,Cuirong Zhu,Lei Qin 국제구조공학회 2008 Structural Engineering and Mechanics, An Int'l Jou Vol.29 No.5

In this paper, the double displacement coupled statics and dynamics of the electromechanical integrated electrostatic harmonic drive are developed. The linearization of the nonlinear dynamic equations is completed. Based on natural frequency and mode function, the double displacement coupled forced response of the drive system to voltage excitation are obtained. Changes of the forced response along with the system parameters are investigated. The voltage excitation can cause the radial and tangent coupled forced responses of the flexible ring. The flexible ring radius, ring thickness and clearance between the ring and stator have obvious influences on the double displacement coupled forced responses.

Dynamic analysis of a short cylinder piezo motor

Lizhong Xu,Shanjie Du 대한기계학회 2014 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.28 No.8

The bar-type traveling wave ultrasonic motor is simple, inexpensive, easy to use, and suitable for miniaturization. Its operating performanceis significantly affected by the dynamic behavior of the vibrator. In this work, the analytical equations for calculating the dynamicbehavior of the motor vibrator are presented using the ring model. The natural frequencies and vibrating modes of the motor areinvestigated using the analytical equations. Changes in the natural frequencies along with the motor parameters are analyzed. The forcedresponses of the vibrator to two input signals with a phase difference of 90º are given. A FEM analysis in ANSYS is used to simulate thenatural frequencies and vibrating modes of the vibrator. A test is conducted to illustrate the analytical calculative results.

Double displacement coupled forced response for electromechanical integrated electrostatic harmonic drive

Xu, Lizhong,Zhu, Cuirong,Qin, Lei Techno-Press 2008 Structural Engineering and Mechanics, An Int'l Jou Vol.29 No.5

In this paper, the double displacement coupled statics and dynamics of the electromechanical integrated electrostatic harmonic drive are developed. The linearization of the nonlinear dynamic equations is completed. Based on natural frequency and mode function, the double displacement coupled forced response of the drive system to voltage excitation are obtained. Changes of the forced response along with the system parameters are investigated. The voltage excitation can cause the radial and tangent coupled forced responses of the flexible ring. The flexible ring radius, ring thickness and clearance between the ring and stator have obvious influences on the double displacement coupled forced responses.

Double DOF control of an electromechanical integrated toroidal drive

Xu, Lizhong,Liu, Xin Techno-Press 2007 Smart Structures and Systems, An International Jou Vol.3 No.1

The electromechanical integrated toroidal drive is a new drive system. For the control of the drive, the torque fluctuation and the steady-state errors should be removed and the fast response to the input change should be achieved. In this paper, the torque fluctuation of the drive system is analyzed and expressed as Fourier series forms. The transfer function of the torque control for the drive system is derived from its electromechanical coupled dynamic equations. A 2-DOF control method is used to control the drive system. Using definite parameter relationship of the 2-DOF control system, the steady errors of the torque control for the drive system is removed. Influences of the drive parameters on the control system are investigated. Using proper drive parameters, the response time of the control system is reduced and the quick torque response of the drive system is realized. Using a compensated input voltage, the torque fluctuation of the drive system is removed as well. The compensated input voltage can be obtained from the torque fluctuation equation and the transfer function. These research results are useful for designing control system of the new drive.

A harmonic movable tooth drive system integrated with shape memory alloys

Lizhong Xu,Zongxing Cai,Xiaodong He 국제구조공학회 2019 Smart Structures and Systems, An International Jou Vol.23 No.4

Continuous rotating SMA actuators require motion conversion mechanisms, so their structure is relatively complex and difficult to realize the miniaturization. Here, a new type of continuous rotating actuator driven by SMA is proposed. It combines the movable tooth drive with SMA drive. The structure and working principle of the integrated movable tooth drive system is introduced. The equations of temperature, stress and strain of memory alloy wires, and the output torque of drive system are given. Using these equations, the temperature, the output forces of the SMA wires, and output torque of the drive system are studied. Results show that the compact drive system could give large output torque. To obtain large output torque plus small fluctuation, large eccentricity and small diameter of the SMA wire should be taken. Combined application of ventilation cooling and high current can increase the rotary speed of the drive system.