The Theoretical And Testing Research On The Noises-Control Equipments Used In An Electro-Hydraulic Servo System

The noise of the electro-hydraulic servo system not only influences the working stability and longevity of hydraulic components, but also influences the missionary's healthy. In the worst, the accident would happen. With the hydraulic servo system development with high speed, high pressure and great power, the fluid-borne noise becomes more serious and it has become an important factor which limited the technology's evolution. So it is very important to reduce the fluid-borne noise of the electro-hydraulic servo systems. It not only can greatly improve the working environments but also can enhance the system's whole performance and longevity.In the first, an electro-hydraulic servo system was studied. In this work, the principles of the hydraulic piston pump pulsation noise, the hydraulic impact noise, the pipeline noise and the load-noise of the electro-hydraulic system were analyzed, and the range of pulsation noise frequency was brought out. In order to reduce the noises, the accumulator, hole-style muffler, soft tube and active pressure feedback-equipment were adopted. In order to guarantee the creditability of the testing data processing, this work brings forward a DP method whose error salient degree is not larger than 0.05.Secondly, with matrix methods and tube dynamic characters equations, the mathematic models of the tube's resonant specialties and the noise absorbing specialties of the accumulator in the tube system were built, and the mathematic models of the noise absorbing specialties of the soft tube and muffle were brought. With the Matlab computational tools and the simulation and the computation, the resonance-length was computed and the frequency-chart of the accumulator absorbing the pressure-pulsation and the hydraulic impact were educed. By the same method, the effecting curve according with the structural parameters of the noise absorbing specialties of the soft tube and hole-style muffle was depicted. From the research, it can be seen that mounting the accumulator before the servo valve can absorb the hydraulic pressure pulsation noise and the hydraulic impact better, increasing the size of the soft tube and hole-style muffler can broaden the strip of the noise reducing frequency.In the end, to increase the damp of the electro hydraulic servo system which exits low damp generally, the active pressure feedback-equipment was adopted. The step respond curve of the hydraulic cylinder's piston indicate that although active pressure feedback-equipment can increase the system's damp, the parameter should feet the system's needs.The theory study and experiments indicate that the model building methods which used matrix and tube dynamic characters equations can analyze the tube-system's dynamic characters. The noise reduction methods and equipments designed by the work can highly reduce the system's fluid-borne noise.