Online control calculation for models containing near colinearity and uncertainty

An apparatus for increasing robustness in a MPC controller controlling a process, the process having at least two manipulated variables, at least two controlled variables, and at least one active operation constraint, the apparatus comprising:

• a computer means coupled to the MPC controller and executed by a processor, the computer means:
• receiving a user defined robustness factor;
• identifying an ideal case optimum value for the process;
• calculating an economic objective giveaway tolerance using the user defined robustness factor;
• calculating steady-state target values for the at least two manipulated variable and the at least two controlled variable for each cycle of the process using the economic objective giveaway tolerance and the ideal case optimum value;
• detecting (i) if the at least two manipulated variables and the at least two controlled variables have a near collinear relationship with each other;
• and (ii) whether the calculated steady-state target values indicate movement of the at least two manipulated variables in a weak direction;
• and
• avoiding MPC controller movement of variables along a weak direction by adjusting the at least one active operation constraint according to the user defined robustness factor if the near collinear relationship is utilized by the MPC controller, resulting in increased robustness for the MPC controller.

A computer program product for increasing robustness in a Model Predictive Control (MPC) controller monitoring a process, the process having at least two manipulated variables, at least two controller variables, and at least one active constraint, the computer program product comprising:

• in a digital processor, a computer readable medium embodying program instructions;
• the program instructions, when executed by the digital processor causes the MPC controller to:
• receive a user defined robustness factor;
• identify an ideal case optimum value for the process;
• calculate an economic objective giveaway tolerance using the user defined robustness factor;
• calculate steady-state target values for the at least two manipulated variable and the at least two controlled variable for each cycle of the process using the economic objective giveaway tolerance and the ideal case optimum value;
• detect (i) if the at least two manipulated variables and the at least two controlled variables have a near collinear relationship and (ii) if the calculated steady-state target values indicate movement of the at least two manipulated variables in a weak direction;
• and
• avoid controller movement of variables along a weak direction by adjusting the at least one active operation constraint according to the user defined robustness factor if the near collinear relationship is utilized by the MPC controller.