Discrete optimal control using quadratic performance criterion with model transformations

The authors describe optimal process control using a quadratic performance index. The linear discrete difference model with constant coefficients is used because the digital computer as a controller is a discrete device. The quadratic performance criterion is used as the cost functional to be minimized because it is mathematically tractable and has a nice closed form solution. The multivariable representations solve some of the variable coupling effects. This is usually done through assigning proportional weights for the weighting matrices of the quadratic performance criterion