Balancing optimization of U-shaped assembly lines based on stochastic chance constrained programming

To reduce the productivity loss or frequent disruption due to processing time fluctuation in the stochastic U-shaped assembly line balancing of type-II, a precedence constraint was established so as to ensure the material flow between entrance and exit of the line. A bi-objective stochastic chance-constraint programming model was formulated with two goals of improving productivity and stability simultaneously. Owing to the properties such as randomness, non-linearity and intractability of the proposed model, the stochastic chance constraint related to processing times was transformed into its deterministic equivalent, two incompatible goals were normalized and combined, and two nonlinear constraints were linearized. Therefore, a mixed-integer linear programming model was achieved, which could be solved by GAMS/Cplex. Experimental results demonstrated that under the stochastic processing times, the proposed stochastic chance-constraint program model and its solution methodology could lead to a vast promotion in the production stablity at the cost of tiny productivity loss. © 2016, Editorial Department of CIMS. All right reserved.