Research On Comprehensive Performance Of Electro-hydraulic Vibration Test Bench

The electro-hydraulic angle vibration test bench studied in this paper is used for calibrating gyroscope.The device can output high-frequency and high-precision sinusoidal position signal without considering phase lag.The frequency response of the electro-hydraulic angle vibration test bench is influenced by many factors.The hardware factors include the frequency response of the hydraulic power mechanism,the bandwidth of the servo valve and the sensor,the hardware response time,and the mechanical resonance frequency of the test bench and so on.The software factors include sampling time and control algorithm and so on.The result caused by these factors is that the amplitude will decay rapidly and the waveform distortion will increase greatly when the electro-acoustic vibration bench works at high frequencies.Therefore,this paper focuses on designing a reasonable general planning for the electro-hydraulic angle vibration test bench,selecting the hardware that can meet the requirements of the high-frequency range work and designing a stable and reliable control algorithm,so that the electro-hydraulic angle vibration test bench can trace sinusoidal position signals with high-precision at high frequency range.This article first introduces the layout generally and working principle of the electro-hydraulic angle vibration test bench.Then,the overall design and the related parts design of the electro-hydraulic angle vibration test bench are completed according to the technical specifications,and the static mechanical analysis are performed for the important parts.After that,the nonlinear mathematical model of the electro-hydraulic vibration test bench is established based on the general planning,and the simulation analysis are performed by using Simulink.The performance of the electro-hydraulic vibration test bench is analyzed by the open-loop Bode diagram,the closed-loop zero-pole diagram and the step response of the system.It is determined that the adjustment of the control algorithm focuses on improving the hydraulic damping ratio and the system bandwidth while ensuring the stability of the system.A three-variable controller for position,velocity and dynamic pressure is designed based on the zero-pole distribution.Firstly,the parameters of the feedback element in the three-variable controller are determined by the root trajectory method.Then,the feedforward of the three-variable controller is determined according to the adjusted zero-pole distribution.Through simulation analysis,feedback is very limited to improve the bandwidth of the system.Feedforward has a certain effect on reducing the resonance of the system at high frequencies.The bench is able to meet the system performance index at 270 Hz under the three-variable controller.In order to realize the goal of amplitude error is less than 10% when the sinusoidal signal frequency is above 270 Hz and the system doesn't require the phase delay of the tracking signal in the high frequency range,the amplitude signal generator based on the least mean square algorithm is designed.Determining the step length of the minimum mean square algorithm at each frequency point by using the interpolation method,so that the controller has strong practicality and adaptability.Through simulation and analysis,the amplitude signal generator can track the sinusoidal signal with a frequency of 500 Hz and the track error can meet the technical requirements.Finally,an electro-hydraulic vibration test bench test system is built.In order to achieve a fast and accurate sampling cycle,the system application software,control algorithms and protection algorithms are designed on Windows+RTX platform.The sinusoidal frequency sweep experiment is conducted to verify the accuracy of the general planning of the electro-hydraulic angle vibration test bench.The actual mathematical model of the electro-hydraulic angular vibration test bench is obtained through system identification.Compared with the actual mathematical model,the simulation model is deficient at the low frequency range.Then,the simulation model combined with the identification results guides the controller debugging.The effectiveness of the three-state controller and the external amplitude controller is verified through debugging.