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RU-2861608-C1 - METHOD FOR NON-CONTACT MEASUREMENT OF SHAPE AND DIMENSIONS OF BODY CROSS-SECTION

RU2861608C1RU 2861608 C1RU2861608 C1RU 2861608C1RU-2861608-C1

Abstract

FIELD: control and measuring equipment. SUBSTANCE: invention relates to methods for non-contact determination of geometric parameters of cross-sections of bodies. In the method, calculating the coordinates of base points located along the length of the perimeter of an ellipse at equal distances between base points and at fixed distances from a central point located within the controlled cross-section of the body, measuring the distances from the base points to the corresponding control points on the contour of the body cross-section in the direction of the perpendiculars of the base points, calculating the distance taking into account the reflectivity of the measured body, determining the coordinates of all obtained control points and calculating the shape and dimensions of the body cross-section using known formulas. EFFECT: expanding the scope of application and increasing the accuracy of determining the geometric parameters of body cross-sections by using a new method for measuring geometric parameters. 1 cl, 2 dwg

Inventors

  • Cherednichenko Vitalii Sergeevich
  • LANKIN MIKHAIL VLADIMIROVICH

Dates

Publication Date
20260506
Application Date
20251212

Claims (7)

  1. A method for contactless measurement of the shape and dimensions of a cross-section of an object, including the placement of a base point at a fixed distance from a central point located within the controlled cross-section of the body, measuring the distances from the base point to N control points located on the contour of the cross-section of the body, determining the coordinates of all control points in a rectangular coordinate system using a mathematical apparatus, characterized in that N base points are placed around the body being measured along the length of the perimeter of an ellipse P with semi-axes A and B , at an equal distance between the base points L bases , equal to:
  2. the distance from the k -th base point ( k = 1… N ) to the control point is calculated taking into account the reflectivity of the measured body according to the expression:
  3. Where l k - the result of measuring the distance between k -base and control points;
  4. C is the value of the reflectivity of the body surface;
  5. the coordinates of all control points in a rectangular coordinate system are determined according to the expressions:
  6. Where t k - a parameter determined using an iterative algorithm in which the distance is known to be L bases between two adjacent base points t k And t k +1 calculated using the formula:
  7. in this case the parameter of the initial base point t k is set to 0, then the parameter value is changed t k +1 next base point from the value t k until the moment when L calc equal to the ratio of the perimeter of the ellipse to the number of base points with a given error, is assigned to the parameter t k meaning t k +1 , found at the previous stage, and the iterative process continues until the condition is met k > N .

Description

The invention relates to the field of control and measuring technology, namely to methods for contactless determination of geometric parameters of cross-sections of quasi-cylindrical bodies. A "Method for Inspecting Part Diameters" is known (RU Patent No. 2301968, published June 27, 2007, IPC G01B 11/08, G01B 11/24). The essence of this method is that the cross-sectional diameter of a body is determined by the size of the shadow created by the inspected body when illuminated by a light beam consisting of multiple parallel rays. The optical sensor implementing the shadow method consists of two units: an emitter and a receiver. The radiation from a semiconductor laser or LED is collimated by a lens. When the inspected object is placed in the area of the collimated beam, its shadow image is scanned by an array of photodetectors or formed by a telecentric optical system on an array of photodetectors. Based on the position of the shadow boundaries, a processor calculates the diameter of the object. The disadvantage of this method is that only the diameter of the body cross-section is determined. A known method is implemented in a device for inspecting the cross-section of an object (patent SU No. 945649, published July 23, 1982, IPC G0LB 11/08). The essence of this method is that the cross-sectional diameter of a body is determined by the size of the shadow created by the inspected body when illuminated by a light beam consisting of multiple parallel rays. This method determines multiple cross-sectional diameters of the body in different directions by scanning it using a system of mirrors. The disadvantages of the method include the complexity of its implementation, as well as the impossibility of using it to control the cross-sections of bodies with concave sections. The closest in its technical essence to the claimed method and taken as a prototype is the "Method for Determining a Set of Parameters of the Cross-Section of Quasi-Cylindrical Bodies" (patent RU No. 2645002, published on 15.02.2018, IPC G01B 11/08, G01B 11/24, IPC G01B 11/28). According to the prototype method, which includes the location of a base point at a fixed distance from a central point located within the controlled cross-section of the body, the distances are measured from the base point to control points located on the contour of the cross-section of the body, during rotation of the controlled cross-section of the body around an axis passing through the central point, at equal angular intervals. Calculation of the lengths of the segments between the central and control points as the difference between the fixed distance of the base point and the measured values and determination of the coordinates of all control points in a rectangular coordinate system using mathematical apparatus. A disadvantage of the prototype is that measurements are taken from a reference point, requiring precise positioning relative to a central point within the cross-section. Furthermore, the prototype method only determines distances at a single reference point, requiring rotation or translation of the object or device, as well as synchronizing measurements at equal angular intervals. This necessitates the use of complex mechanical drives and increases the time required for measurements. This method also does not take into account the reflectivity of the measured object, which can reduce the accuracy of the obtained data when working with objects with different surface reflectivities. Furthermore, the prototype does not allow dynamic tracking of changes in the shape and size of the cross-section of the measured object if the time required for these changes is less than the time required for the measurement. This limits the method's applicability, complicates its practical implementation, and reduces accuracy. The objective of the invention is to obtain geometric coordinates of the cross-section of bodies, eliminating the use of complex mechanical moving devices and the need for precise positioning of the measured body relative to the central point. The technical result of the invention is to increase the measurement accuracy of the method for determining the geometric parameters of the cross-section of a body by means of contactless measurement of the coordinates of a plurality of surface points, taking into account the reflectivity of the body surface. The technical result in the invention is achieved in that in the method of contactless measurement of the shape and dimensions of a body section, including the location of a base point at a fixed distance from a central point located within the controlled cross-section of the body, measuring the distances from the base point to N control points located on the contour of the cross-section of the body, determining the coordinates of all control points in a rectangular coordinate system using a mathematical apparatus, wherein N base points are located around the measured body along the length of the perimeter of an