Structured light based wheel multiple parameter online measurement system and measurement method thereof

An online measurement method for multiple parameters of a wheel based on structured light, comprising the following steps:

• first step, installation and calibration:
• (1) installing an online measurement system for multiple parameters of a wheel based on structured light on a detection section,
• the online measurement system for multiple parameters of a wheel based on structured light comprising:
• a system controller, a wheel sensor, a first wheel online measurement device, and a second wheel online measurement device, wherein the wheel sensor, the first wheel online measurement device and the second wheel online measurement device are all connected to the system controller, and the wheel sensor, the first wheel online measurement device and the second wheel online measurement device are sequentially disposed side by side in a train forward direction;
• both the first wheel online measurement device and the second wheel online measurement device comprise a tread structured light unit, a profile structured light unit and a two-dimensional image sensor, the profile structured light unit, the tread structured light unit and the two-dimensional image sensor being arranged along the outer side of the same steel rail;
• the tread structured light unit emits n line lasers, where n≥2, and when the n line lasers are projected onto a wheel, n wheel tread contour curves are formed;
• the profile structured light unit emits m line lasers, where m≥1, and when the m line lasers are projected onto the wheel, m wheel profile contour curves are formed;
• the m wheel profile contour curves intersect with the n wheel tread contour curves in an area where a tread contour line is spaced apart from an inner side surface by 60-80 mm;
• and the n wheel tread contour curves and the m wheel profile contour curves are all within an imaging range of the two-dimensional image sensor;
• (2) calibrating structured light parameters;
• second step, train wheel parameter detection:
• (1) obtaining measured train wheel contour information:
• when the train passes, after a wheel sensor detects a wheel, operating a first wheel online measurement device and a second wheel online measurement device simultaneously, denoting profile contours of m line lasers of profile structured light units of the first and second wheel online measurement devices on the wheel as lp1-1, lp1-2, . . . , lp1-m, lp2-1, lp2-2, . . . , lp2-m, denoting tread contours of n1 line lasers of a tread structured light unit of the first wheel online measurement device on the wheel as lt1-1, lt1-2, . . . , lt1-n1, respectively, denoting tread contours of n2 line lasers of a tread structured light unit of the second wheel online measurement device on the wheel as lt2-1, lt2-2, . . . , lt2-n2, respectively, and respectively taking, by two two-dimensional image sensors, contour images P1-1 and P2-1, P1-2 and P2-2, . . . , P1-k and P2-k of two segments of profile structured light and tread structured light at the bottoms of k groups of wheels at k times, where k is a natural number;
• (2) reconstructing a first group of three-dimensional contour images:
• performing three-dimensional image reconstruction on P1-1 and P2-1 according to images P1-1 and P2-1 taken by a first group of two two-dimensional image sensors and the structured light parameters calibrated in (2) of the first step to obtain three-dimensional reconstructed tread structured light contours lt′1-1, lt′1-2, . . . , lt′1-n1, lt′2-1, lt′2-2, . . . , lt′2-n2 and three-dimensional reconstructed profile structured light contours lp′1-1, lp′1-2, . . . , lp′1-m, lp′2-1, lp′2-2, . . . , lp′2-m;
• (3) calculating a first group of measured wheel contour parameters:
• processing a first group of three-dimensional reconstructed tread structured light contours lt′1-1, lt′1-2, . . . , lt′1-n1, lt′2-1, lt′2-2, . . . , lt′2-n2 to synthesize a wheel tread curve lt′, and defining to calculate a first group of wheel rim height and rim thickness according to the tread curve lt′;
• or separately processing all n1+n2 reconstructed tread contours to obtain n1+n2 wheel rim height and rim thickness values, eliminating the rim height and rim thickness values with large errors, averaging the remaining wheel rim height and rim thickness values, and calculating the first group of wheel rim height and rim thickness;
• (4) calculating a first group of measured wheel diameters:
• fitting m circles C1, C2, . . . , Cm according to m pairs of profile structured light contours lp′1-1, and lp′2-1, lp′1-2 and lp′2-2, . . . , lp′1-m and lp′2-m after the first group of three-dimensional images is reconstructed, obtaining m diameters D1, D2, . . . , Dm according to a fitted circle equation, correcting the m fitted circle diameters D1, D2, . . . , Dm to a rolling circle according to the contour curve lt′ to obtain m rolling circle diameter values D1′, D2′, . . . , Dm′, eliminating the rolling circle diameter values with large errors, and then averaging to obtain a first group of wheel diameter values D;
• (5) when k is greater than 1, repeating steps (2) to (4) for the remaining k−1 groups of images P1-2 and P2-2, . . . , P1-k and P2-k, calculating k−1 groups of wheel rim height, rim thickness and diameter values, eliminating the values with large errors for k groups of wheel rim height, rim thickness and diameter values, and then averaging to obtain final measured wheel rim height, rim thickness and diameter values;
• (6) tread abrasion and peeling recognition:
• when there is no abrasion or peeling on a wheel set, setting all the profile structured light contours after the three-dimensional image reconstruction at k times to be continuously slowly changing arcs, and when one of the profile structured light contours is abruptly changed, judging abrasion or peeling depending on the type of abrupt change;
• and
• third step, real-time judgment alarm:
• solving differences by comparing the wheel diameter, rim height and rim thickness values measured in the second step with standard values;
• judging whether an alarm prompt is required according to the diameter difference, the rim height difference and the rim thickness difference;
• judging whether an alarm prompt is required according to whether there is abrasion or peeling;
• when all the parameters do not exceed set values and there is no abrasion or peeling, considering that it is safe;
• and when one or more parameters exceed the set values or there is abrasion or peeling, determining that a system has a hidden danger, and giving an alarm prompt.