A new adaptive MPC system

Current generation of industrial MPC technology has two main disadvantages: 1) it is very costly to implement and to maintain an MPC system; 2) the performance in disturbance reduction is low. To solve these two problems, an adaptive MPC technology is introduced. It consists of three modules, a Control Module, an Identification Module and a Monitor Module. It can perform various steps of an MPC project automatically and in a parallel manner. Thus, the efficiency of MPC commissioning and maintenance can be increased by a factor of 3 or more. In the MPC Control Module, an adaptive disturbance model is used to improve control performance and robustness. A prototype of the adaptive MPC system has been applied successfully to a PTA unit. Due to its simplicity and user friendliness, this technology may change the way MPC is applied and can make MPC feasible for all process industries, not just the refining/petrochemical industry. Recent tests have shown that the adaptive disturbance model can increase control performance considerably. A traditional adaptive MPC controller performs sample-wise identification and adaptation of both process models and disturbance models without monitoring the test condition and model quality. The new adaptive MPC system is very different from the traditional adaptive control: the process model is adapted on demand (when activated by the Monitor Module) where test signals are used in model identification; the disturbance model is adapted sample-wise without using test signals. We believe that this new scheme is more adequate for the control of large scale industrial processes than the traditional adaptive controller.