A Study On Integral Algorithm For Acceleration Test To Get Displacement And Application

The vibration displacement plays an important role in the field of engineering anddetermining the boundary conditions and finite element analysis. However,Displacement sensor needs demanding test conditions, in many cases cannot beimplemented; Relatively，test by acceleration sensor and twice integration to getdisplacement signal is convenient and easy, but the trend-term often when interferenceacceleration integral, resulting serious displacement curve paranoid. Aimed to solvethis problem, this paper proposes a “low-frequency attenuation integration algorithm”based on the integral of the frequency domain, and uses a variety of examples on theintegration algorithm validation and error evaluation, researched the choice ofintegration parameters impact on the results; finally，We build the acceleration testbench who contains limit collision, the engineering application characteristics of theseintegration algorithm are discussed. In this thesis, the content and conclusions aresummarized as follows:(1) By the deduction of several existing acceleration integration algorithm on thetheoretical formula found their deficiencies in the integration trend term error controland effective information retention. To solve this problem, we proposed a newintegration algorithm based on the frequency domain integral called "low-frequencyattenuation integration algorithm".(2) Through the harmonic function superimposed example, forced vibration, freevibration and impact vibration simulation example to validate and error research theexisting and this paper proposed integration algorithm. The results show that: thelow-frequency attenuation integration algorithm this paper proposed is not only integralerror smaller, but also the integral control parameter selection of fault tolerance, so it iseasier to operate.(3) In order to study the characteristics of the in engineering applications forlow-frequency attenuation integration algorithm, based on a motorcycle engine, wedesigned and built an acceleration test bench who contains limit collision, and based onthe software called LABVIEW developed the control system of this bench, so thisbench can test acceleration and displacement by itself.(4) In order to correct the error of the acceleration test system, using the bench wetested the acceleration on the engine piston, and solved the theoretical value. Through several tests and the comparison of theoretical and measured values, we get the testsystem error, and correct this error by polynomial fitting.(5) Using the above bench, tested both the acceleration and displacement of the"reciprocation lever", corrected the test error on acceleration, and integrated theacceleration signal to the displacement signal respectively, compared the displacementcome from the acceleration whose test error are corrected and are not. The resultsshowed that: by the correction of test error, the integral resultant displacement signalamplitude error is significantly reduced.(6) In different motor speed, by the contrast of the displacement measured andcome from acceleration, we found that: when the signal fundamental frequency is low,the displacement come from acceleration have a big error; But with the improvement ofthe signal baseband, the error is reduced. Based on this test system, when theacceleration baseband is higher than3.8Hz, the integral peak error is less than10%,which can meet the needs of engineering test; when the acceleration baseband higherthan4.35Hz, the integral peak error is less than5%, in that case, the ideal displacementsignal can be achieved by this method.