Improved contract net protocol for job-shop rescheduling

DING Bin-chu， TANG Hong-tao
（Institute of Industrial Engineering， Zhejiang University of Technology， Hangzhou 310014， China）

Abstract： Aiming at the problem of flexible job shop rescheduling，a rescheduling algorithm which mixed Q-learning based evolutionary programming with windows rolling technology was presented. In the algorithm，local and global rolling methods were designed in the purpose of reducing the size of the problem. The process of evolution and Q-learning driven was improved by the rolling mechanism，which was easier to absorb and repair the influence of dynamic events. The learning ability of the contract net consultation mechanism which was integrated with the algorithm was improved. Finally，the feasibility of the consultation mechanism was verified by simulation example. The result shows that the improved contract net consultation mechanism and basic contract net consultation mechanism have good response ability，but improved contract net consultation mechanism has more advantages in maximum completion time and processing departure time.
Key words： flexible job shop； rescheduling； windows rolling technology； Q-learning；evolutionary programming； contract net consultation mechanism