Research On Moment Of Inertia Measurement Technology Under Damping Conditions

The moment of inertia measurement technology all has the extremely widespreadapplication in many fields. In the process of measurement, the exogenic actionrepresented by the air resistance will affect the motion of rigid body, leading todeviation. In particular for craft products with special shapes and sizes, this deviationis more obvious. However, in engineering practice, the air damping effects tend to beignored. In all kinds of methods of the moment of inertia measurement，the torsionalpendulum method is of advantages of large bearing quality and higher precision, andthe technology of moment of inertia of torsion pendulum measurement equipment ismature with complete product models, being capable of meeting the needs of variousmeasurements. On the basis of the traditional torsional pendulum method, to study theair damping on the influence of the rotational inertia measurement has importantresearch significance. Air resistance exists generally in the motion of rigid body, andthis makes the research be of certain reference value for other related technical fields.Relied on a national defense research project, the related technologies are studiedin this paper with the adoption of the torsional pendulum method to measure themoment of inertia under the condition of damping.The quantitative relationship between the air damping ratio and the moment ofinertia of objects in motion is analyzed based on the measurement principle of thetorsional pendulum method. The optimized curve fitting method is deduced on thebasis of the free attenuation method to measure the air damping ratio via theinvestigation of the existing measuring methods of the damping ratio. The principle ofthe grating displacement method is given to measure the oscillation curve in thetorsional pendulum motion with the analysis of the linear model of moment of inertia.The equipment of rotational inertia measurement hardware is set up with thedevelopment of the operating software, and flat experiment samples are designed anddeveloped to simulate the complex shaped objects in practical engineering.The experiment scheme and concrete steps are determined according to thestudied measurement technology, and a large number of experiments of moment ofinertia measurement under the condition of damping are completed with the adoption of software and hardware equipment and experimental equipment of the measurementsystem. Summarized the experimental results. The influence of air damping on theresults of rotational inertia measurement is analysed as well as the relationship and thechange rule of damping ratio with conditions of physical parameters and postureposition of the experiment object.By making use of the experimental results, the error compensation algorithm ofthe moment of inertia measurement based on air damping ratio was deduced, and thecorrection method of the measurement result was studied. By comparing theexperimental data with the correction results, the compensation effect of the algorithmwas shown in the form of chart, and the measurement accuracy was improved.