A Sequential Interval Optimization Method for Tolerance Design

In this paper, a sequential interval optimization method for tolerance design is proposed. Through this method, not only the optimal solution is obtained, but also the allowable manufacturing errors can be provided. The manufacturing errors are depicted by the interval model, based on which the interval optimization model can be constructed. Directly solving the constructed interval optimization would encounter the double-loop nested problem, which will cause low computational efficiency. To overcome the problem, a sequential interval optimization method is proposed. At each cycle, the interval optimization is first transformed into deterministic optimization by the possible degree of the interval, and then the first-order Taylor expansion method is applied to transform the nonlinear model into the linear form. The design variables and the design manufacturing errors are updated by solving the linear optimization problem. Three examples are investigated to verify the accuracy and efficiency of the present method.