Abstract: Traditional multidisciplinary design optimization (MDO) is a deterministic design method without taking into account the effect of uncertainty factors. In order to reduce the influence of uncertainty on system performance, the first-order reliability method (FORM) is introduced into MDO, and the mathematical model of FORM based collaborative optimization (CO) is set up. The methods of CO and FORM based CO are applied to solving the reliability based MDO for gear transmission of a reducer, and the results of the two methods show that the optimal solution obtained by the FORM based CO satisfies the requirement of reliability. Within the optimization of systematic level of the two methods, the slack variable is introduced to convert consistency equality constraints to non-equality constraints, thus making the algorithm easy to converge. The method of FORM based CO improves the reliability of the gear system, so it has practical engineering significance.

Key words: Collaborative optimization, First-order reliability method, Gear transmission, Multidisciplinary design optimization