Control that estimates delayed manipulated variables

A non-transitory computer readable storage device transitory signal having instructions for causing a computer to implement a method, the method comprising:

• calculating and sending, via a controller, a manipulated variable via a network to control an actuator in a process;
• receiving information at the controller identifying a value which was actually applied by the actuator together with a time stamp indicating a time of applying a signal;
• receiving process data at the controller representative of a process state, the process data acquired by sensors over the network together with the time stamp indicating the time when acquisition took place;
• estimating at the controller an applied actuator input signal along with the process state, fusing received process data acquired by sensors and received information identify the value which was actually applied by the actuator arriving late within a set maximum delay;
• and
• using a difference between the calculated manipulated variable and the estimated applied signal to correct a next calculated manipulated variable prior to sending the next calculated manipulated variable to the actuator via the controller;
• wherein a correction signal is added to the controller output which is a difference between the calculated manipulated variable and the estimated applied signal.

A device comprising:

• a programmed hardware controller to calculate a manipulated variable value for an actuator in a process;
• an estimator to receive a manipulated variable value applied by the actuator, including a time stamp indicating a time of applying the actual manipulated variable value, to estimate a signal applied by the actuator, and to provide a delay via a feedback correction term to compensate for network delays in communications between the controller and the actuator, wherein the feedback correction term is driven by a difference between an estimate of actuator input applied in a previous time step estimated by a Kalman filter and a one-step delayed tentative manipulated variable, wherein the one-step delayed tentative manipulated variable comprises output of the controller without delay compensation, wherein the estimator uses a locally stored history of sent actuator inputs and a network delay distribution model to initially estimate actuator input and wherein a delay compensator is coupled to the estimator and the controller to modify the manipulated variable value based on a difference between the manipulated variable value and the estimated signal applied by the actuator;
• and
• a delay compensator coupled to the estimator and controller to modify the calculated manipulated variable responsive to the difference between the estimated actuator input signal provided by the estimator and the manipulated variable computed by the controller.