Design And Research On An Apparatus And Method Of Rotator Inertia In Place Measeurment

In the precision instruments machinery weapons systems aerospace and other fields, moment of inertia is the essential parameters, which impact the characteristics of components and systems. In the machinery industry in order to determine the working performance and features of the rotary components, measure the moment of inertia is necessary. Therefore, accurate measure of the rotary inertia has great significance to scientific research and industrial applications. But for the assemble rotary system, the system’s inertia testing always related friction torque, and the accurate test friction torque is difficulties, so inertia rotary system assembled accurately test is a key point research. Response to these problems this project propose a rotary inertia measurement method, which can reduce the impact of the friction. The project based on this measurement method developed a measuring device. Summarized as follows:1. Analysis the resistance torque factor of rotator inertia in place measurement and propose a measurement methodThe projects propose a new method of measure the moment of inertia of the falling weight system, and build the mathematical models. The method adopts two ways to solve the two friction resistance factor were resolved. One way is to adopt a pair of discs, which have the same mass but different moment of inertia. This kind of discs can eliminate the influence of friction resistance for the system by different loads factor. Another way is to find the acceleration which is in the same velocity moment to calculate the moment of inertia. In this way can eliminate the influence of friction resistance for the system by different speed.2. Build rotator inertia in pace measurement test platformThe measurement test platform is completed build. Experimental platform collect data by a encoder and a data acquisition card. Write control software by Visual Basic. Experimental platform design includes mechanical design, pneumatic circuit design, hardware circuit design and software design. Time synchronization device which improves the measure repeatability of equipment, automatic winding system can improve the degree of equipment’s automation, simplifying operation.3. Experiments of rotational inertia in place measurement deviceBased on the experiment platform, a great deal of the experimental test has been done. Such as repeatability test, the start point of calculation test, the mass of falling body test, the falling height test and the envelope angle test.Repeatability test proved that for the falling weight system, time synchronization device can effectively reduce the experimental uncertainty introduced by human factors, which improve the accuracy of the experimental results.The start point of calculation test proved the start friction torque of bearing has a great impact of the test, based of 50 repetitions test the experiment data shows that the starting point of the calculation at 20% is suitable.The mass of the falling body test proved that the weight of the falling body must match the measure object. The falling height test proved that a minimum falling height is needed when the height below this minimum height the measurement errors. The envelope angle test proved that the envelope angle has little impact to the experiment. When the test object inertia is 2.606gm2 the mass of the falling body is 150g falling height is 1.8m envelope angle is 160°,50 replications experiments, the maximum measurement error is close to 1%.The project developed the method and device of the rotating body inertia in place measurement, and reducing bearing friction resistance torque for the impact of measurement, as to the traditional measurement falling weight system the new method have improve the measurement accuracy.