Contact type hot-rolled steel plate thickness on-line measuring device and on-line measuring method

The invention provides a contact type hot-rolled steel plate thickness online measuring device and method, and belongs to the technical field of steel rolling production. The online measuring device comprises a track truss, a distance measuring sensor and a walking mechanism are arranged on the track truss, and servo thickness measuring calipers are arranged on the walking mechanism; the controller is used for controlling the traveling mechanism to move according to the hot-rolled steel plate position information fed back by the distance measuring sensor; the moving seat and the fixed seat are oppositely arranged, the first connecting ring and the second connecting ring are slidably connected with the moving seat and the fixed seat respectively, the first pressing head and the second pressing head are connected with the first connecting ring and the second connecting ring respectively, the first pressing head and the second pressing head clamp a hot-rolled steel plate to be measured in the thickness direction