The invention discloses a method and a
system for detecting the size of a
train wheelset online. According to the invention, the
diameter of a wheel
flange vertex circle and the
train speed are acquired through
laser correlation photoelectric switches, a wheel
flange lowest point and the height between the wheel
flange lowest point and the ground are positioned through an eddy-
current sensor, points on a wheel are detected through inside and outside 1D
laser displacement sensors so as to acquire a wheel
tread contour line, and thus the wheel flange height, the wheel flange thickness and the wheel
diameter are acquired. The method disclosed by the invention is low in cost, and detection for the wheelset size such as the wheel flange height, the wheel flange thickness and the wheel
diameter can be realized by only requiring two 1D
laser displacement sensors, four laser correlation photoelectric switches and the eddy-
current sensor; and the diameter of the wheel flange vertex circle and the
train speed can be calculated by the four laser correlation photoelectric switches, the eddy-
current sensor determines the height between the wheel flange lowest point and the ground and a serial number of a sampling point at the moment, the outside 1D laser displacement sensor is combined, relative wheelset size of the detected wheel can be acquired through corresponding
algorithm processing, and the operation is simple.