| Countries in the world are increasingly competing in the field of high-end textile equipment,and people attach great importance to its noise problem.They all take the noise situation of high-end textile equipment as an important reference for whether the equipment meets the standard.However,traditional noise abatement methods can only decrease the noise except the low-frequency band.So it cannot really eliminate the strong low-frequency noise present in high-end textile equipment.At present,the method that can eliminate low-frequency noise well is ANC method.This topic takes the tufted carpet loom in high-end textile equipment as the research object,and uses the adaptive active noise control method to study the low-frequency noise control of the tufted carpet loom.Firstly,the structure and working principle of the tufted carpet loom are analyzed.The noise generated by each component during the operation of the tufted carpet loom is analyzed.Through the Donghua test signal acquisition system,the noise signal of the tufted carpet loom was got.The time-frequency and spectrum diagram of the noise are analyzed.The noise distribution of the tufted carpet loom in each frequency band is clarified,which provides a theoretical basis for the active noise reduction of the tufted carpet loom.Then,combined with the principle of active noise control,the structure of the active noise control system of the tufted carpet loom are analyzed.A feedforward dual-channel adaptive active noise control system model for tufted carpet looms based on the Fx LMS algorithm is established,and a dual-channel adaptive active noise control algorithm for tufted carpet looms is derived in detail.The identification method of the secondary path of the tufted carpet loom is studied,and the identification error of the transfer function of the secondary path is analyzed.The off-line identification experiment of the secondary path of the tufted carpet loom was carried out by using the dual microphone method,and the secondary path identification program was written.The estimated value of the transfer function of the secondary path finally obtained has a small mean square error,which can fit ANC system requirements of the tufted carpet loom.Then,the simulation study of the feedforward dual-channel adaptive active noise control of the tufted carpet loom was carried out.Using the method of control variables,the influence of the constriction value and the length of FIR filter in the algorithm on the noise reduction are discussed.A good noise elimination effect can be achieved by selecting a reasonable FIR filter and constriction value.Finally,an experimental study on the dual-channel active noise reduction of the tufted carpet loom was carried out.Using the dual-channel Fx LMS algorithm,a dualchannel adaptive active noise control system for the tufted carpet loom based on the Lab VIEW control program is designed.A two-channel active noise control platform for tufted carpet looms is built,which can perform real-time noise control,and can achieve a good noise reduction effect in a closed space area. |
