Online stochastic control of dimensional quality in multistation manufacturing systems

Abstract In the current paper, a control law is devised for flexible tooling element adjustments in a multistation manufacturing system based on the in-process product measurements and the state-space model of dimensional error flow through this system. The control law is devised so that the dimensional product quality at the end of the line is as close to the nominal as possible in the least squares sense, taking into account the measurement and process noise, as well as the accuracy of actuation of flexible tooling elements. The condition of controllability of product quality is introduced and dimensional quality variations of the product with and without the newly introduced stochastic quality control law are compared. It is proven that the newly proposed control algorithm reduces variations of dimensional product errors and that the controllability condition is beneficial to both the expected product quality as well as for its variations. Capabilities of the newly proposed method for stochastic control of dimensional quality in multistation manufacturing systems are illustrated in an example of a machining system used for the manufacturing of an automotive cylinder head by a major automotive manufacturer.

[1]  Daniel E. Whitney,et al.  Modeling and controlling variation propagation in mechanical assemblies using state transition models , 1999, IEEE Trans. Robotics Autom..

[2]  Darek Ceglarek,et al.  Quality-driven Sequence Planning and Line Configuration Selection for Compliant Structure Assemblies , 2005 .

[3]  Yoram Koren,et al.  Stream-of-Variation Theory for Automotive Body Assembly , 1997 .

[4]  Darek Ceglarek,et al.  Fixture Failure Diagnosis for Autobody Assembly Using Pattern Recognition , 1996 .

[5]  Yong Chen,et al.  Diagnosability Study of Multistage Manufacturing Processes Based on Linear Mixed-Effects Models , 2003, Technometrics.

[6]  Yu Ding,et al.  Fault Diagnosis of Multistage Manufacturing Processes by Using State Space Approach , 2002 .

[7]  Jionghua Jin,et al.  State Space Modeling of Sheet Metal Assembly for Dimensional Control , 1999 .

[8]  C. D. Meyer,et al.  Generalized inverses of linear transformations , 1979 .

[9]  Darek Ceglarek,et al.  Fixture Failure Diagnosis for Sheet Metal Assembly with Consideration of Measurement Noise , 1999 .

[10]  J. A. Robinson,et al.  Analysis of Variation Transmission in Manufacturing Processes—Part I , 1999 .

[11]  Daniel W. Apley,et al.  Tolerance allocation for compliant beam structure assemblies , 2003 .

[12]  Jun Ni,et al.  Measurement scheme analysis in multi-station machining systems , 2002 .

[13]  Qiang Huang,et al.  State space modeling of dimensional variation propagation in multistage machining process using differential motion vectors , 2003, IEEE Trans. Robotics Autom..

[14]  Jie Zhu,et al.  Stream of Variation Based Error Compensation Strategy in Multi-Stage Manufacturing Processes , 2005 .

[15]  Yu Ding,et al.  Diagnosability Analysis of Multi-Station Manufacturing Processes , 2002 .

[16]  Jun Ni,et al.  Measurement Scheme Synthesis in Multi-Station Machining Systems , 2004 .

[17]  Qiang Huang,et al.  Stream of Variation Modeling and Analysis of Serial-Parallel , 2004 .

[18]  Yu Ding,et al.  MODELING AND DIAGNOSIS OF MULTISTAGE MANUFACTURING PROCESSES: PART I - STATE SPACE MODEL , 2000 .

[19]  J Ni,et al.  Bayesian approach to measurement scheme analysis in multistation machining systems , 2003 .

[20]  Dariusz Ceglarek,et al.  Impact of fixture design on sheet metal assembly variation , 2004 .

[21]  Qiang Huang,et al.  Diagnosis of multi-operational machining processes through variation propagation analysis , 2002 .

[22]  Jun Ni,et al.  Stream of variation based analysis and synthesis of measurement schemes in multi-station machining systems , 2001 .

[23]  Yu Ding,et al.  Optimal sensor distribution for variation diagnosis in multistation assembly processes , 2003, IEEE Trans. Robotics Autom..

[24]  Jaime A. Camelio,et al.  Modeling Variation Propagation of Multi-Station Assembly Systems With Compliant Parts , 2003 .

[25]  Henry Stark,et al.  Probability, Random Processes, and Estimation Theory for Engineers , 1995 .

[26]  Jun Ni,et al.  Dimensional Errors of Fixtures, Locating and Measurement Datum Features in the Stream of Variation Modeling in Machining , 2003 .