Q. He, S. Su, and R. Du
[1] C.A. Reymondin, G. Monnier, D. Jeanneret, & U. Pelaratti,The theory of horology (Switzerland: Swiss Federation ofTechnical Colleges, 1999). [2] Y. Fu & R. Du, A study on the dynamics of Swiss leverescapement mechanism, Int. Symp. on Collaborative Researchin Applied Science, Vancouver, Canada, 2005, 8–15. [3] The official website of MicroSet: http://www.bmumford.com/microset.html. [4] Official website of Witschi Electronic Ltd., Switzerland, Ba-sic Training: http://www.witschi.com/download/Training_EN.pdf. [5] S. Su & R. Du, Signature analysis of mechanical watch move-ments, Second Asian Int. Symp. on Mechatronics, Hong Kong,December 2006, D3-1. [6] L. Cohen, Time-frequency distribution: A review, Proc. IEEE,77(7), 1989, 941–981. doi:10.1109/5.30749 [7] A. Papandreou-Suppappola, Applications in time-frequencysignal processing (Boca Raton, Florida: CRC Press, 2003). [8] N.E. Huang, Z. Shen, & S.R. Long, The empirical modedecomposition and the Hilbert transform for nonlinear andnon-stationary time series analysis, Proc. The Royal Societyof London, A(454), 1998, 903–995. [9] Y. Yang, D. Yu, & J. Cheng, A roller bearing fault diagnosismethod based on EMD energy entropy and ANN, Journal ofSound and Vibration, 294, 2006, 269–277. doi:10.1016/j.jsv.2005.11.002 [10] A. Parey, M. El Badaoui, F. Guillet, & N. Tandon, Dynamicmodelling of spur gear pair and application of empirical modedecomposition-based statistical analysis for early detection oflocalized tooth defect, Journal of Sound and Vibration, 294,2006, 547–561. doi:10.1016/j.jsv.2005.11.021 [11] J. Cheng, D. Yu, & Y. Yang, A fault diagnosis approachfor roller bearings based on EMD method and AR model,Mechanical Systems and Signal Processing, 20, 2006, 350–362. doi:10.1016/j.ymssp.2004.11.002 [12] H. Li, X. Deng, & H. Dai, Structural damage detection using thecombination method of EMD and wavelet analysis, MechanicalSystems and Signal Processing, 21, 2007, 298–306. doi:10.1016/j.ymssp.2006.05.001 [13] Z.K. Peng, P.W. Tseb, & F.L. Chu, An improved Hilbert–Huang transform and its application in vibration signal analysis,Journal of Sound and Vibration, 286, 2005, 187–205. doi:10.1016/j.jsv.2004.10.005 [14] R.L. Dequeiroz & K.R. Rao, Time-varying lapped transformsand wavelet packets, IEEE Trans. on Signal Processing, 41,1993, 3293–3305. doi:10.1109/78.258074 [15] H. Ocak, K.A. Loparo, & F.M. Discenzo, Online tracking ofbearing wear using wavelet packet decomposition and proba-bilistic modeling: A method for bearing prognostics, Journalof Sound and Vibration, 302, 2007, 951–961. doi:10.1016/j.jsv.2007.01.001 [16] X. Fan & M.J. Zuo, Gearbox fault detection using Hilbertand wavelet packet transform, Mechanical Systems and SignalProcessing, 20, 2006, 966–982. doi:10.1016/j.ymssp.2005.08.032 [17] Y. Wu & R. Du, Feature extraction and assessment usingwavelet packets for monitoring of machining processes, Me-chanical Systems and Signal Processing, 10(1), 1996, 29–53. doi:10.1006/mssp.1996.0003 [18] X. Li, L. Qu, G. Wen, & C. Li, Application of wavelet packetanalysis for fault detection in electro-mechanical systems basedon torsional vibration measurement, Mechanical Systems andSignal Processing, 17(6), 2003, 1219–1235. doi:10.1006/mssp.2002.1517 [19] Q. He, F. Kong, & R. Yan, Subspace-based gearbox conditionmonitoring by kernel principal component analysis, MechanicalSystems and Signal Processing, 21(4), 2007, 1755–1772. doi:10.1016/j.ymssp.2006.07.014 [20] B. Boashash & P. Black, An efficient real-time implementa-tion of the Wigner-Ville distribution, Processing of Acoustics,Speech, and Signal, 35, 1987, 1611–1618.Appendix A: Modal Frequencies of a MechanicalWatch MovementFinite Element Analysis (FEA) is performed to evaluatethe modal frequencies of the escapement. As shown in Fig.A1(a), the escapement consists of a balance wheel, a palletfork, and an escape wheel. SolidWorks r was used to drawthe solid model of the escapement and then to conductFEA. In the FEA, the materials of the balance wheel areset as copper and ruby, the materials of the pallet fork arealloy steel and ruby, and the material of the escape wheelis alloy steel. The boundary conditions are very importantin FEA. Take the escape wheel, for example. It can onlyrotate in the axial direction, so a frictionless support wasgiven to each end of the pivot (see Fig. A1(b)). The sameconstraints can be imposed on the balance wheel and thepallet fork. The mesh type is solid mesh. The FEA results(the modal frequencies) are summarized in Table A1.196Figure A1. FE model of the escapement.Table A1Modal Frequencies of the EscapementMechanical Parts Modal Frequencies (Hz)Balance wheel 481, 1752, 2488, 6417, 6766, 18331,18892, 20223, 21537Pallet fork 16779, 21150, 22212Escape wheel 9117, 11262, 12667, 18728, 19425
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