Non-contact dimensional measurements are desirable in several hot-working processes, such as hot forging processes. A dimensional measurement method, used to reduce scrap and waste during forming processes, is presented, based on a spectrum selective method and stereo vision structured light technique. Using the spectrum selective method, the image of the hot forging can be obtained without interference by self-emitted radiation. A coded single pattern is projected towards the hot forging to label characteristic lines, and simplify the process of finding correspondences between image pairs. The depth can be estimated by triangulation. An ellipse is fitted to the reconstructed 3D data for calculating the diameter of the forging. Experiments in a forging workshop are conducted to measure the diameters of round forgings. The results verify the effectiveness of the presented method.

A novel six-axis heavy force sensor based on the Stewart platform is proposed. To improve the capability of load bearing, the upper platform and the lower platform of the Stewart platform is fixed to a load sharing beam. Based on the deduced force/moment mapping matrix, the isotropy and sensitivity performance indices of the sensor are analysed comprehensively by employing the performance atlases. Theory analysis and experimental research of the effects of the load sharing beam on the performance indices are conducted. The results show that the change rule of the experiments basically agrees with the curve of theory, which provides necessary references of the theory and experiment for the design of a six-axis heavy force sensor with a large measuring range.