Research On Active Control Of Gear Box Noise

Gear box is widely used in the application of general power machinery parts,such as widely used in aviation,shipping,automobile,industrial production or other fields.The frequency properties of gear box inherent noise(line noise)similar to rotating machinery,reciprocating mechanical and electromagnetic equipment(such as transformer,fan,compressor,engine etc.),therefore the research on active control for gear box noise has important reference value for other control occasions.In the design process,algorithm and implementation methods of the active control for line spectrum noise of gear box,this paper carried out the following research work:First of all,through the theoretical analysis on the generation mechanism of radiation noise of gear box,have a more intuitive understanding of the overall structure of the gear box and the generation of radiation noise,and predict that the spectral characteristics of the radiated noise of the gearbox will be based on the speed frequency and showing the characteristics of line-spectrum noise.After measuring the acoustic radiation,box structure vibration and sound power;find out that the active noise control objective is line-spectrum noise;provide the basis for the selection of secondary sound source.Through the coherence analysis of shell vibration and acoustic radiation,consider that the vibration acceleration signal can be used as reference signal in the active noise control system.Sound pressure method is used to measure the sound power,by which the strength of the radiation acoustic of the gear box can be fully depicted.Secondly,from two aspects of the destructive interference of sound wave and the JMC theory based on Huygens principle,describe the theoretical basis of active noise control in detail.The basic principle and implementation process of LMS and FxLMS algorithms are derived by using statistical theory and modern signal processing method.Especially,from the perspective of system analysis,explain the unique advantages of notch filter algorithm in the control of line-spectrum noise.From the engineering application point of view,derive the implementation process of notch filter algorithm and secondary path modeling based on the perturbation method.Further,the adjustment is made on the notch filtering algorithm;use the MATLAB software to simulate and compare the performance of notch filter algorithm and adjusted algorithm in terms of convergence speed and computation capacity.Then,according to the working environment of the gear box,the preliminary design of the physical configuration of the control system is made,especially the acquisition of reference signal,the secondary sound source and the layout design of the error sensor.According to the physical configuration design,make prediction on the noise reduction to judge the feasibility of the control scheme by using theoretical and experimental method.Finally,referring to the previous program design and the empirical conclusion,the final experimental scheme is formed after the modification and improvement.The active noise control experiment is carried out and the validity of notch filter algorithm is verified.Besides that,the advantages and disadvantages of the whole active noise control is summarized and analyzed.