Abstract: In order to confirm the maximum forces acting on local structural interface of the walking mobile chassis for the structural strength design, a mechanical model including all position freedom parameters of the chassis under the operating conditions is established. Furthermore, an optimization model for computing the load acting on the local structure using the bi-level optimization model based on response surface model is proposed. In the first level, the maximum forces acting on local structure of the chassis is optimized by using the sequential quadratic programming method at the given a sets of position parameters. The response surface function between maximum forces state in the local structure and position parameters is constructed by using orthogonal design. In the second level, the genetic algorithm is used to optimize the response surface function. A high precision response surface function is obtained by using an iteration procedure, in which the searching volume is reduced by using the bisection method. The results show that the response surface method is an effective technique for multi-variable optimization of the complex structural system. It is also concluded that the proposed method can provide theoretical basis for designing the walking mobile mechanism.

Key words: Response surface method, Bi-level optimization model, Orthogonal design, Walking mobile chassis