Measurement Noise in PID Control LoopSnapshot of a part of the front panel of the simulator:
Description of the system to be simulatedIn this simulator a process represented by a transfer function (a seried combination of two first order systems and a time delay). You can add random (white) measurement noise. The measurement signal can be filtered by a first order filter or a dead band filter. AimThe aims of this simulator is to observe the unfortunate consequences of meadurement noise in a control loop, and to experience ways to reduce these conseqences. MotivationMeasurement noise is a problen in most practical control loops. The noise gives false or erroneous process information which, via the controller, may give unfortunate excitation of the actuator and the process to be controlled. Below are a few examples of measuremen noise:
If the noise source can not be eliminated, the noise can be attenuated by using a proper signal filter. TasksIf you use the default process parameters you can use the following PID controller parameters (found using the Ziegler-Nichols' closed loop method: Kp=2.8; Ti=1.2; Td=0.3 The controller is assumed to be in auto-mode unless otherwise stated in the tasks below. Start the simulator. Introduce random measurement noise.
Updated 18. January 2008. Developed by Finn Haugen. E-mail: finn@techteach.no. |