Research On Measurement Method Of Internal Cavity Volume Of Solid Rocket Engine

The solid rocket motor combustion chamber is used as a place for storing and burning propellant in the solid rocket engine structure.The volume of the inner cavity and the volume of the inner cavity directly affect the charge of the propellant,thus affecting the launch performance of the solid rocket motor.In addition,the surface of the combustion chamber is coated with an ablative heat-insulating layer and a coating layer,which are soft elastic materials and have a non-contaminating requirement.In view of the above problems,this paper uses the non-contact measurement method to scan the inner cavity of the solid rocket engine in full size,and then obtain the volume of the inner cavity.The work done in this article is as follows:This paper combines the detection requirements of the system with the structural characteristics of the test object,designs the overall test plan of the system,selects the appropriate hardware equipment and builds the test platform.For the measurement accuracy of the designed system,this paper uses the standard gauge block to verify the absolute accuracy and repeatability of the system.The original signal of the laser is affected by the ambient illumination,the surface morphology of the object to be tested and the limitations of the detection device itself.The noise is inevitable.In terms of the characteristics of the noise itself,the median filtering method is used to remove the noise.In this paper,the line laser displacement sensor scanning solid rocket machine cavity contour data is converted into 3D point cloud data.In order to reduce the calculation time,this paper studies the point cloud data reduction method,and uses the string height angle method to streamline the point cloud data.The algorithm measures the data compression by giving the angular error and the chord height error.Finally,the point cloud data space is divided by the octree space division method,and the projection is performed.The volume of the solid rocket engine cavity is characterized by counting the number of pixels.In order to verify the effectiveness of the method,a standard ellipsoid is generated in MATLAB,and its volume is measured by the method mentioned in this paper.Finally,the feasibility of analyzing the measurement results using absolute error and relative error.The experimental results show that by comparing with the actual volume,the final calculated volume relative error is able to achieve accurate measurement of the volume of the tubular cavity.