Design Of Precision Measurement System For Integrated Parameters Of Valve Shaft Parts

The valve is an important part of the spacecraft equipment.The quality of the valve directly affects the reliability of the spacecraft.Realizing high-precision detection of valve parts is an important technical measure to guarantee the sealing,reliability,and stability of aerospace valves,and shaft parts are indispensable components of aerospace valves,it is of great significance to realize its comprehensive parameters(diameter,taper,axis straightness error,acting diameter).In view of the low accuracy and low efficiency existing in current measurement methods,this paper proposes a set of specific measurement solutions,and designs the measurement system to achieve fast and high-precision measurement of valve shaft parts.Through the comparative study on the measurement methods for various parameters of shaft parts,combined with the measurement tasks and technical requirements of the subject,a specific measurement plan was proposed.For the diameter measurement,a specific projection imaging method is used.For the measurement of the axis straightness error,a measurement method is used to extract the coordinates of the points on the axis of the device under test by means of the standard straightness provided by the reference axis.The measurement of taper and working diameter is obtained indirectly through the measurement of other parameters.Using the scanning measurement method,simultaneous measurement of multiple parameters of the DUT is realized.The appropriate coordinate system was established and the specific mathematical model of each parameter was deduced.The axis straightness error was evaluated by iterative search algorithm.According to the measurement plan and technical requirements,the design of the hardware structure of the measurement system was completed.The tooling required for the measurement system completes the mechanical design and selects the key components involved.The position of the device under test is that the height of one end of the device under test is fixed,and the other end can adjust the height through the Z-axis slide.This structure allows the measurement system not only to complete the leveling of the device under test,but also to adapt to different sizes of the device under test.During the measurement process,the X-axis slide table is used to drive the DUT to move so that the measurement system can complete the scanning measurement of the DUT.According to the calculation method of each measured parameter,combined with the electrical structure of the system,the use of Visual Studio 2017 development tools,.NET framework sampling C # programming language to complete the preparation of special measurement software.The main functions of the measurement software are following: using the RS-232 serial port to achieve communication between the host computer and other components in the measurement system;to achieve measurement data acquisition and processing,according to the mathematical model to calculate the measured value of the measured parameters;to achieve the measurement data preservation,finding and report generation.The standard uncertainty synthesis of the system is discussed.The error source of the system is analyzed.Using the error transfer formula and the synthesis method of uncertainty,the overall uncertainty of the measurement system is calculated.It is proved that the measurement system meets the technical specifications and the specific measurement task can be completed.