Improved Cumulative Score Control Chart Based On Cumulative Control Chart

Cumulative sum control chart(CUSUM)is an important component of statistical process control tools to monitor process and to ensure the quality of process' s operation.Traditional CUSUM chart has been more perfect.Cumulative sum improvement based on the idea of "accumulation" have been continuously proposed.And the zone control chart is one of them.But each interval scores of the traditional zone control chart are positive values.In order to optimize its performance,this paper according to the ideas of cumulative score of the bilateral zone control chart,introduces negative score for its improvement and designs a unilateral cumulative score control chart.First of all,this paper introduces the cumulative sum chart and the continuous run sum chart.Secondly,on the basis of the traditional regional score control chart,a unilateral cumulative score of control chart is presented.And by using markov chain method,we calculate the average run length(ARL)and compare it with the related control chart,and find that the result was not significant.To further optimize the improved control chart,combining with fast initial response method,set up fast response values of the improved control chart and compare it's performance with the performance of the CUSUM control chart and the continuous run sum control chart,results shows that the improved control chart has obvious superiority than others.Again,the paper studies the improved cumulative score control chart of variable sampling interval.It compares the improved control chart of variable sampling interval and the improved control chart of fixed sampling interval sampling,and the average time signal as a performance indicators;It also analyses the influence factors of average time signal.Finally,contrastive analysis in the presence of contingency factors,the effect of the improved control chart and CUSUM control chart to monitor the process.