Feedforward Control of Multistage Assembly Processes Using Programmable Tooling

The combination of feedforward control and programmable tooling has emerged as a promising method to reduce product variation in multistage manufacturing systems. Feedforward control allows compensation of deviations on a part-by-part basis using programmable tooling. This paper addresses the problem of designing an optimal feedforward control law that improves quality. The controller design involves deviations estimation (from in-line measurements), variation propagation modeling and analysis, and process/parts constraints. Therefore, a control law is obtained using constrained optimization. A case study is conducted on a multistage assembly of a vehicle side frame to illustrate the developed methodology.