# Simulation-Based Reliability Design Optimization Method for Industrial Robot Structural Design
###### Abstract  
Robots are main elements in Industry 4.0. Research on the design optimization of robots has a great significance in manufacturing industries. There inevitably exist various uncertainties in robot design that have an important influence on the reliability of robots. At present, the design optimization of robots considering the uncertainties is mainly focused on joints design and trajectory optimization. However, for the structural design of robots, deterministic design optimization still plays a leading role. In this paper, a simulation-based reliability design optimization method is proposed to improve the reliability of robots' structural design. In the proposed method, the Latin hypercube sampling (LHS), computer simulation, response surface method (RSM) and SORA (Sequential Optimization and Reliability Assessment) algorithm are integrated to complete the structural design of the robot. Firstly, samples of the uncertainty design variables were obtained by LHS, and then, the reliability performance constraint functions were firstly constructed through the RSM in which the joint simulation of MTLAB and ANSYS was adopted. Afterwards, the reliability design optimization model was established on the basis of the probabilistic reliability theory. At last, the SORA algorithm was employed to realize the optimization. The design optimization problems of the big arm and the small arm of a 6 Kg industrial robot were considered to verify the proposed method. The results showed that the weights of the big arm and the small arm were, respectively, reduced by 7.73% and 25.70% compared with those of the original design, and the design was more effective in ensuring the reliability requirements compared with the deterministic optimization. Moreover, the results also demonstrated that the proposed method has a better computational efficiency compared with the reliability design optimization of the double-loop method. industrial robot; reliability design optimization; big arm; small arm; computer simulation 2023133776. 13.  
design, airplane design, ship design, etc. Due to its outstanding advantages, more and more design optimization methods have been developed for robot body design. [PERSON] et al. [6] proposed a surrogate-based evolutionary optimization method, in which the response surface method is integrated with a multi-objective evolutionary algorithm. Their proposed method can not only improve the robot arm performance, but also alleviate the computational burden. [PERSON] et al. [7] proposed a multi-objective design mechanism for industrial robots. In this design mechanism, the initial and running costs, the stress analysis and the vibration analysis are considered, and therefore the optimum type of material and physical dimensions can be selected for industrial robot arms. [PERSON] et al. [8] proposed a structural optimization method for robot arms, which specially considers the influences of flexible joints on robot dynamics. [PERSON] and [PERSON] [9] analyzed different robot arms designs, in which both geometry and materials are changed, and their findings showed that the cost, efficiency and motor lifetime were all improved by adopting the optimization technology. In addition to the optimization design, the simulation design is an advanced technology that is often used in modern product design. The simulation-based design is practically used to predict the behavior and results of products [10]. Benefited from the development of computer technology, computer simulation design has been widely used in modern mechanical product design, greatly improving design efficiency and product quality. Similar to most mechanical product designs, industrial robot design also extensively adopts computer simulation methods. [PERSON] et al. [11] used a commercial CAD platform to perform the initial design of a robot gripper finger. [PERSON] et al. [12] employed the dynamics simulation software ADAMS to analyze the kinematics of a five-axis industrial robotic arm. [PERSON] et al.