An Improved Development Of The Hydraulic Tube Shock Absorber Test System

As with the development of technology and the pursuit of high commercial efficiency,the requirement of measurement's high accuracy and comprehensive utilization of test data is emerging,and it is the same with shock absorber measurement system.For the air filling tube shock absorber,these examined out unqualified would be discarded in exfactory inspection.However if there is an algorithm to predict the resultant output force when it has not been sealed and the gas has not been injected,the shock absorber producer could adjust the unqualified to qualified and thus can minimize the produce loss.Another problem to be solved is that the exsting shock absorber test system still apply the static sensitivity in the dynamic situation which causes a systematic measurement error,it is necessary to adopt the preciser dynamic sensitivity to the test system.In the paper a force separation method is proposed based on each component force characteristic.The resultant force is composed of damping force,air rebound force produced by pressed air and friction force.According to the character of shock absorber,the damping force can be describled by a function of velocity of absorber's piston.The gas elastic force can be introduced in the ideal gas equation which would transfer to a function of displacement and the friction force can be regarded as a constant since it has nothing to do with neither velocity nor displacement.Arrays of resultant force and displacement data are applied in the calculation of coefficient of these functions based on least-squares-fit method.As for the force transducer dynamic calibration,a standard piezoelectric force transducer is connected with the strain force transducer in series.Through virtual instrument measurement technology a corresponding input-output matrix that is the dynamic sensitivity could be attained.The specific sensitivity coefficient could be calculated through interpolation of the input-output matrix.All the improved function would be embedded in the original LabVIEW-based test software.