Research On Probe Radius Compensation And Equilibrium Mechanism Of Articulated CMM

Reverse Engineering (RE) as a new designing method can do a lot of things in the absorption domestic and international advanced technique, shortening the product's development period and lowering the production cost. Nowadays articulated coordinate measuring machine(ACMM) is becoming more and more popular in the field of RE and gained great interest from the field of RE, because of its a lot of advantages such as convenience to be used, portability to be carried for its small volume and light weight and flexibility to the worktable. Based on a series of previous researches in this field, a lot of researches on contact measurement based on newly developed ACMM were carried out as follow in this dissertation.Firstly, the systematic mechanical design about the links and joints for Articulated Coordinate Measuring Machine is discussed. On the basis of D-H method, the mathematical module and movement equation for probing the joint arm end were built,and the error model of joints was established; Based on the previous research for calibration arithmetic a new calibration block for calibration was designed. By the aid of a series of analysis with exact differential matrix and least squares method equations, calibration of the structure with high precision was achieved. Simultaneity, genetic algorithm is proposed for calibration.Secondly, the equilibrium mechanism used on the laboratory has carried on at present has discussed. Based on analyzing steelyard weight equilibrium mechanism, spring equilibrium mechanism and barometric pressure equilibrium mechanism, the moment equilibrium mechanism was proposed. It both had guaranteed the articulated coordinate measuring machine balance any time, and reduced the load of the joint weight in the greatest degree in the operation project, and also satisfies the request the joint stops at will.Finally,this article has studied probe radius compensation arithmetic when contact measurement. A probe radius compensation arithmetic by the curved surface division was proposed: In view of the natural quadratic surface fitting directly, merely needs several spots to fit the natural quadratic surface; When is not natural quadratic surface, a new algorithm with enveloping canker is proposed, the experiment demonstrated this algorithm practical is feasible.