Measuring method of three-dimensional position and orientation of a moving object for medical robots

A measuring method of 3-D position and orientation of a moving object has been developed, which employed a 2-D position measuring instrument (with only one camera) and three light points attached to the moving object. In order to increase the accuracy of the 3-D measurement, the positions of pupils of the optical system for the 2-D position measuring instrument were introduced to derive the theoretical equations, and the geometrical relation between three light points in the object space was determined experimentally using the 2-D position measuring instrument before conducting 3-D measurements. Based on the principle of our measuring method, static 3-D measurements were conducted. The results showed that the maximum measurement errors of the X, Y, and Z coordinates of three light points were 0.05 mm, 0.1 mm, and 3 mm respectively within the measuring range from Z=-360 mm to 2=-760 mm. The accuracy of the measurement will be increased to the resolution of the 2-D position measuring instrument by improving the experimental apparatus and method