Publications (3)1.96 Total impact
- [Show abstract] [Hide abstract] ABSTRACT: Purpose ‐ The purpose of this paper is to propose an optimization method by combining artificial immune algorithm and finite element analysis to find the optimal exciting electrode of a piezoceramic plate type ultrasonic motor vibrator. Design/methodology/approach ‐ The artificial immune algorithm is selected as optimizer for its merit of fast convergence to global optimal solution. The finite element analysis is used to calculate the motion trajectory of contact point. The objective function is the work that the vibrator does to rotor. The design variables are the boundaries of exciting electrode on piezoceramic plate vibrator surface. Findings ‐ The calculated results and the experimental results show that using this method, both the position and the size of optimal exciting electrode of this ultrasonic motor can be quickly and accurately determined. Originality/value ‐ In order to successfully design an ultrasonic motor, both the position and the size of the exciting electrode must be investigated, so as to change more electric energy into mechanical energy. In this paper, an optimization method by combining artificial immune algorithm and finite element analysis is proposed for the exciting location optimization of a piezoceramic plate type ultrasonic motor to obtain large power output.
- [Show abstract] [Hide abstract] ABSTRACT: To explore ways of obtaining large power output, a piezoceramic plate type ultrasonic motor excited by superposition of two vibration modes with different frequencies was developed and investigated. When the two working modes are superposed together, the contact point performs straight line movement, and gives the rotor a chain of intermittent unidirectional pushes. The vibrator vibration can be significantly intensified, thus the vibrator can do more work to the rotor than each single vibration mode exciting. Experimental results showing that the average output power is about 2.22 and 3.28 times as that of the two single modal exciting cases separately.
- [Show abstract] [Hide abstract] ABSTRACT: Assessing the dynamics of heart rate fluctuations can provide valuable information about heart status. In this study, regularity of heart rate variability (HRV) of heart failure patients and healthy persons using the concept of singular value decomposition entropy (SvdEn) is analyzed. SvdEn is calculated from the time series using normalized singular values. The advantage of this method is its simplicity and fast computation. It enables analysis of very short and non-stationary data sets. The results show that SvdEn of patients with congestive heart failure (CHF) shows a low value (SvdEn: 0.056 ± 0.006, p < 0.01) which can be completely separated from healthy subjects. In addition, differences of SvdEn values between day and night are found for the healthy groups. SvdEn decreases with age. The lower the SvdEn values, the higher the risk of heart disease. Moreover, SvdEn is associated with the energy of heart rhythm. The results show that using SvdEn for discriminating HRV in different physiological states for clinical applications is feasible and simple.
Shanghai Jiao Tong University
Shanghai, Shanghai Shi, China
- Department of Instrument Science and Engineering